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  • 1.
    Andersen, Ken
    et al.
    European Spallation Source ESS AB, Lund, Sweden.
    Bigault, Thierry
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Buffet, J. C.
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Correa, Jonathan
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Hall-Wilton, Richard
    European Spallation Source ESS AB, Lund, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Höglund, Carina
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Guerard, Bruno
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Khaplanov, Anton
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Kirstein, Oliver
    Linköping University.
    Piscitelli, Fransesco
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    van Esch, P.
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Vettier, Christian
    European Spallation Source, Lund, Sweden.
    10B multi-grid proportional gas counters for large area thermal neutrondetectors2013In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, Vol. 720, 116-121 p.Article in journal (Refereed)
    Abstract [en]

    3He was a popular material in neutrons detectors until its availability dropped drastically in 2008. The development of techniques based on alternative convertors is now of high priority for neutron research institutes. Thin films of 10B or 10B4C have been used in gas proportional counters to detect neutrons, but until now, only for small or medium sensitive area. We present here the multi-grid design, introduced at the ILL and developed in collaboration with ESS for LAN (large area neutron) detectors. Typically thirty 10B4C films of 1 μm thickness are used to convert neutrons into ionizing particles which are subsequently detected in a proportional gas counter. The principle and the fabrication of the multi-grid are described and some preliminary results obtained with a prototype of 200 cm×8 cm are reported; a detection efficiency of 48% has been measured at 2.5 Å with a monochromatic neutron beam line, showing the good potential of this new technique.

  • 2.
    Eriksson, Fredrik
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Johansson, GA
    Hertz, HM
    Gullikson, EM
    Kreissig, U
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    14.5% near-normal incidence reflectance of Cr/Sc x-ray multilayer mirrors for the water window2003In: Optics Letters, ISSN 0146-9592, Vol. 28, no 24, 2494-2496 p.Article in journal (Refereed)
    Abstract [en]

    Cr/Sc multilayer mirrors, synthesized by ion-assisted magnetron sputter deposition, are proved to have a high near-normal reflectivity of R = 14.5% at a grazing angle of 87.5degrees measured at the wavelength A = 3.11 nm, which is an improvement of more than 31% compared with previously published results. Elastic recoil detection analyses show that the mirrors contained as much as 15 at. % of N and traces of C and O. Soft x-ray reflectivity simulations reveal interface widths of sigma = 0.34 nm and an exceptionally small layer thickness drift of similar to1.6 X 10(-5) nm/multilayer period throughout the stack. Simulations show that a reflectivity of R = 25.6% is attainable if impurities and layer thickness drift can be eliminated. The abrupt interfaces are achieved with ion assistance with a low ion energy of 24 eV and high ion-to-metal flux ratios of 7.1 and 23.1 during Cr and Se sputter deposition, respectively. In addition, a near-normal incidence reflectivity of 5.5% for the C VI emission line (lambda = 3.374 nm) from a laser plasma source was verified. (C) 2003 Optical Society of America.

  • 3.
    Stefanescu, I.
    et al.
    Technical University of Munich, Germany .
    Abdullahi, Y.
    Technical University of Munich, Germany .
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Defendi, I.
    Technical University of Munich, Germany .
    Hall-Wilton, R.
    European Spallat Source ESS AB, Sweden .
    Hoglund, C.
    European Spallat Source ESS AB, Sweden .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Zee, M.
    Technische Universität München, D-85748 Garching, Germany.
    Zeitelhack, K.
    Technical University of Munich, Germany .
    A B-10-based neutron detector with stacked MultiWire Proportional Counters and macrostructured cathodes2013In: Journal of Instrumentation, ISSN 1748-0221, Vol. 8, no P12003Article in journal (Refereed)
    Abstract [en]

    We present the results of the measurements of the detection efficiency for a 4.7 angstrom neutron beam incident upon a detector incorporating a stack of up to five MultiWire Proportional Counters (MWPC) with Boron-coated cathodes. The cathodes were made of Aluminum and had a surface exhibiting millimeter-deep V-shaped grooves of 45 degrees, upon which the thin Boron film was deposited by DC magnetron sputtering. The incident neutrons interacting with the converter layer deposited on the sidewalls of the grooves have a higher capture probability, owing to the larger effective absorption film thickness. This leads to a higher overall detection efficiency for the grooved cathode when compared to a cathode with a flat surface. Both the experimental results and the predictions of the GEANT4 model suggests that a 5-counter detector stack with coated grooved cathodes has the same efficiency as a 7-counter stack with flat cathodes. The reduction in the number of counters in the stack without altering the detection efficiency will prove highly beneficial for large-area position-sensitive detectors for neutron scattering applications, for which the cost-effective manufacturing of the detector and associated readout electronics is an important objective. The proposed detector concept could be a technological option for one of the new chopper spectrometers and other instruments planned to be built at the future European Spallation Source in Sweden. These results with macrostructured cathodes generally apply not just to MWPCs but to other gaseous detectors as well.

  • 4.
    Hammarström, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Ali Malik, Muhammad
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Mishra, Rajesh
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Svensson, Samuel
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    A catalytic surface for amyloid fibril formation2008In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100Article in journal (Refereed)
    Abstract [en]

    A hydrophobic surface incubated in a solution of protein molecules (insulin monomers) was made into a catalytic surface for amyloid fibril formation by repeatedly incubate, rinse and dry the surface. The present contribution describes how this unexpected transformation occurred and its relation to rapid fibrillation of insulin solutions in contact with the surface. A tentative model of the properties of the catalytic surface is given, corroborated by ellipsometric measurements of the thickness of the organic layer on the surface and by atomic force microscopy. The surfaces used were spontaneously oxidized silicon made hydrophobic through treatment in dichlorodimethylsilane.

  • 5.
    Johansson, Leif
    et al.
    Linköping University, Department of Physics, Chemistry and Biology.
    Virojanadara, Chariya
    Linköping University, Department of Physics, Chemistry and Biology.
    Eickhoff, Th.
    Drube, W.
    A comparative photoemission study of polar and nonpolar SiC surfaces oxidized in N2O2004In: Surface Science, ISSN 0039-6028, Vol. 552, no 1-3, 251-259 p.Article in journal (Refereed)
    Abstract [en]

    Photoemission studies of oxidized SiC samples grown ex situ in N 2O, at a temperature of 900 °C, on the (0001), (0001̄), (112̄0) and (101̄0) surfaces are reported. Angle resolved data from the Si 1s and Si 2p core levels and the Si KL2,3L2,3 Auger transitions are analyzed and compared to data from a sample grown in O2 on the (0001) surface. The results show oxide growth and no oxy-nitride formation. The growth rate is found to be smallest for the Si-terminated (0001) surface and highest for the nonpolar (101̄0) surface. The presence of two oxidation states, Si+4 and a suboxide, are required to explain and model recorded Si 1s, Si 2p and Si KLL spectra. The SiO2 shift is found to be smaller on the (0001) surface than on the other three surfaces, which is attributed to an oxide thickness dependence of the shift. A layer attenuation model describes satisfactorily the intensity variations observed in the core level components versus electron emission angle when assuming the suboxide at the interface. Estimates made of the thickness of the oxide layers show that the oxidation rate for the (0001) surfaces is about half of that for the (101̄0) surface and that the oxidation rate for the (112̄0) and (0001̄) surfaces are similar but somewhat smaller than for the (101̄0) surface. The amount of suboxide is found to be smaller on the nonpolar than on the polar surfaces. © 2004 Elsevier B.V. All rights reserved.

  • 6.
    Sadollah Khani, Azar
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Shahid Chamran University, Iran.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Kazeminezhad, Iraj
    Shahid Chamran University, Iran.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Eriksson, Martin O.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    A detailed optical investigation of ZnO@ZnS core-shell nanoparticles and their photocatalytic activity at different pH values2015In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 41, no 5, 7174-7184 p.Article in journal (Refereed)
    Abstract [en]

    In this study zinc oxide nanoparticles (NPs) were synthesized via a co-precipitation method and were covered by zinc sulfate using a chemical approach at a temperature of 60 degrees C forming ZnO@ZnS core-shell nanoparticles (CSNPs). In order to investigate the effect of the shell thickness on the optical and photocatalytic properties, many samples were grown with different concentration of the sulfur source. The results show that, covering ZnO with ZnS leads to form a type II band alignment system. In addition, the band gap of the ZnO@ZnS CSNPs was found less than both of the core and the shell materials. Also the emission peak intensity of the ZnO NPs changes as a result of manipulating oxygen vacancies via covering. The photocatalytic activity of the ZnO@ZnS CSNPs was invpstigated for degradation of the Congo red dye. As dye pollutants can be found in mediums with different pH, the experiments were performed at three pH values to determine the best photocatalyst for each pH. Congo red dye degradation experiments indicate that the ZnO@ZnS CSNPs act more efficiently as a photcatalyst at pH values of 4 and 7 compare to the pure ZnO NPs.

  • 7. Vassiljev, A
    et al.
    Grimvall, Anders
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Mathematics, Statistics .
    Larsson, M
    A dual-porosity model for nitrogen leaching from a watershed2004In: Hydrological Sciences Journal, ISSN 0262-6667, Vol. 49, no 2, 313-322 p.Article in journal (Refereed)
    Abstract [en]

    The MASONW (MACRO + SOILN + Watershed) model describing nitrogen leaching in watersheds was developed and tested. The model is based on the MACRO and SOILN models. The dual-porosity model MACRO simulates water flow on the field scale. The SOILN model describes turnover and leaching of nitrogen. Two main features of a watershed have been added into these two models: (a) the existence of a river system, and (b) variable thickness of the aeration zone within a watershed. Good agreement between the output of the MASONW model and observed data for water discharge and nitrate concentrations were achieved in the Odense watershed (496 km2) in Denmark.

  • 8.
    Ali Soomro, Razium
    et al.
    University of Bristol, England; University of Sindh, Pakistan.
    Richard Hallam, Keith
    University of Bristol, England.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    Tahira, Aneela
    University of Sindh, Pakistan.
    Jawaid, Sana
    University of Sindh, Pakistan.
    Tufail Hussain Sherazi, Syed
    University of Sindh, Pakistan.
    Sirajjuddin,
    Univ Sindh, Natl Ctr Excellence Analyt Chem, Jamshoro 76080, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    A highly selective and sensitive electrochemical determination of melamine based on succinic acid functionalized copper oxide nanostructures2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 127, 105090-105097 p.Article in journal (Refereed)
    Abstract [en]

    This study presents the development of a highly selective and sensitive electrochemical sensor for the determination of melamine from aqueous environments. The sensor system is based on functionalised marigold-like CuO nanostructures fabricated using a controlled hydrothermal process, where the utilised succinic acid is considered to play a dual role as a functionalising and growth controlling agent (modifier). The fabricated nanostructures exhibit sharp and well-ordered structural features with dimensions (thickness) in the range of 10-50 nm. The sensor system exhibits strong linearity within the concentration range of 0.1 x 10(-9) to 5.6 x 10(-9) M and demonstrates an excellent limit of detection up to 0.1 x 10(-10) M. The extreme selectivity and sensing capability of the developed sensor is attributed to the synergy of selective interaction between succinic acid and melamine moieties, and the high surface area of marigold-like CuO nanostructures. In addition to this, the developed sensor was also utilised for the determination of melamine from real milk samples collected from different regions of Hyderabad, Pakistan. The obtained excellent recoveries proved the feasibility of the sensor for real life applications. The sensor system offers an operative measure for detecting extremely low melamine content with high selectivity in food contents.

  • 9.
    Lindahl, Daniel
    et al.
    Linköping University, Department of Management and Engineering.
    Stodell, Henric
    Linköping University, Department of Management and Engineering.
    A Human Factors Analysis of Optical Distortion in Automotive Glazing2007Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The glazing is today a part of the car design. The customer is more or less taking for granted that his or her view from inside the car is a direct mirror of the outside world. With more complex shapes, lower installation angles and thinner glass it is a great challenge to produce even better quality at a lower price. While the windscreen is regulated by law, the lack of well specified requirements for the optics in the backlight (rear window), together with the absence of direct customer complaints, is causing the optical quality of the backlight to decrease. The requirements and measuring methods used today are described in technical terms and do not correspond to the human perception of optical distortion.

    This report is a first step towards new technical requirements, for the optics of backlights, based on the driver’s perception of optical distortion. The knowledge of how optical transmission distortion occurs, how it should be measured and how it affects the driver, is essential in order to control it.

    Several databases were searched and contacts with experts were established, in order to gain knowledge. The connection between the technical requirements and the human perception of optical distortion in backlights was investigated by using psychophysical methods. A within factorial design was employed with two independent variables; viewing distance from backlight to tailing object and fixation time (viewing time). The result showed a significant difference in perception of optical distortion between 25 and 75 metres. Moreover, optical distortion is, according to the test, more disturbing during free fixation time than for fixation times of about one second.

    The requirements often used for backlights today (12 ± 5 millimetres) allow distortions that 68 percent of the test subjects perceived as disturbing. In order to please the test driver from Volvo the requirements need to be as high as 12 ± 2 millimetres, which correspond to the 96th percentile. Furthermore, the result confirms that dynamic measurements are needed to find a connection to human perception of optical distortion. The principles of a new measuring method that measures the deformation and the dynamic distortion were developed to show the possibilities of measuring what the driver perceives.

    Even if a good measuring method can help controlling the produced glazing it is not enough to optimize the quality of the production. More important is the choice of thickness and curvature of the glass, the installation angle and the manufacturing method. It is important to set about the origin of the problem and develop a good routine of how to work with optical distortions. Optical distortions in backlights, similar to the tested backlight, have a low probability to disturb the driver in such extent that it has an effect on the driving. Nevertheless, it is a source of irritation and discomfort, which do not belong in a premium car.

  • 10.
    Lindgren, D
    et al.
    Lund University, Solid State Physics and the Nanometer Structure Consortium, Sweden.
    Heurlin, M
    Lund University, Solid State Physics and the Nanometer Structure Consortium, Sweden.
    Kawaguchi, K
    Lund University, Solid State Physics and the Nanometer Structure Consortium, Sweden.
    Borgström, M T
    Lund University, Solid State Physics and the Nanometer Structure Consortium, Sweden.
    Pistol, M-E
    Lund University, Solid State Physics and the Nanometer Structure Consortium, Sweden.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology. Lund University, Sweden.
    Samuelson, L
    Lund University, Solid State Physics and the Nanometer Structure Consortium, Sweden.
    Gustafsson, A
    Lund University, Solid State Physics and the Nanometer Structure Consortium, Sweden.
    A luminescence study of doping effects in InP-based radial nanowire structures2013In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 471, no 1, 012040Article in journal (Refereed)
    Abstract [en]

    We have used micro-photo- and cathodo-luminescence at low temperatures to study the effects of sulphur doping in InP and radial InP/InAs/InP structured nanowires. Samples with pure wurtzite crystal structure, with modulated wurtzite/zincblende crystal structure and with different radial InAs growth times were investigated. We observed a doping concentration gradient along the nanowires, the location of segments of different crystal structure and thickness fluctuations on the monolayer scale of the InAs layer.

  • 11.
    Båvall, Lennart
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    A measurement approach to determination of coating thickness with eddy currents and to a capacitive person detector for robot safety2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research presented in this thesis is about coating thickness measurements using eddy currents, and a capacitive detector for detecting humans, for safety in industry.

    A method for determination of coating thickness of a copper-plated steel wire by measurement of the internal wire impedance, when this is forced by a constant, sinusoidal current, is presented. An electromagnetic model describes how the internal impedance depends on the thickness of the coat, taking into account non-linear effects in the steel. Numerical calculations based on the model are compared with results from measurements.

    Determination of coating thickness on plane samples using an elliptically shaped coil is the objective of two investigations. The first is about determination of thickness of silver coatings on a flat brass substrate by measuring the impedance of a thin elliptic test coil. An electromagnetic model based on a dyadic Green function formulation of the problem is described. A Green function expansion in elliptic vector wave functions is derived, from which the electric field and hence the impedance is evaluated by scattering superposition. The model uses an elliptical co-ordinate system and gives an expression of the coil impedance in closed form. Results from calculations using this model and experimental measurements are presented for different values of the eccentricity of the coil and the thickness of the coating for some chosen frequencies. The second investigation also deals with determination of coating thickness with a thin elliptic coil, but is applied for a flat steel substrate, where the coating was made of copper. Thedescribed model, which allows the sample also to be permeable, is in this case based on a second-order potential formulation from which the magnetic vector potential and hence the coil impedance is evaluated. The derivation utilizes a proper choice of transversal field, giving a scalar Helmholtz equation from which the solution to the boundary value problem is separated. The resulting integral equation is expressed in closed form. Performed calculations and experimentsshow how the model can be used to model a steel surface with a coating of copper to find the impedance as a function of the coating thickness and the eccentricity.

    Finally capacitive detection of humans for safeguarding in industry has been studied. The work describes how the electric and magnetic fields change when a human body, approximated by a dielectric prolate spheroid, is placed in an originally uniform homogeneous electric field. The evaluation of the fields utilizes a potential solution, arising from the Laplace equation, giving the fields in terms of the Legendre polynomials, from which the reactive power impinging into the detector volume is calculated. Numerical calculations and experiments have beenperformed both in a full-scale prototype for detection of humans and in a small-scale model with paraffin and aluminium bodies.

    List of papers
    1. Determination of coating thickness of a copper-plated steel wire by measurement of the internal wire impedance
    Open this publication in new window or tab >>Determination of coating thickness of a copper-plated steel wire by measurement of the internal wire impedance
    1998 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, Vol. 47, no 4, 1013-1019 p.Article in journal (Refereed) Published
    Abstract [en]

    A measurement of the internal impedance of a copper-cladded steel wire by a quote measurement of the voltage across and current through the wire can be used as a method to determine the cladding thickness. An electromagnetic model accounting for the internal impedance with different values of the coating thickness on a steel wire is described. Numerical calculations based on this model have been carried out and compared with measurements. An example shows how the method can be used to model a steel wire with a coating of copper to find the expected impedance as a function of coating thickness

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-87163 (URN)10.1109/19.744660 (DOI)
    Available from: 2013-01-11 Created: 2013-01-11 Last updated: 2013-01-11
    2. Determination of thickness of silver coatings on brass by measuring the impedance of a thin elliptic coil
    Open this publication in new window or tab >>Determination of thickness of silver coatings on brass by measuring the impedance of a thin elliptic coil
    2007 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, Vol. 56, no 3, 790-799 p.Article in journal (Refereed) Published
    Abstract [en]

    To measure the impedance of a thin elliptically shaped coil, in presence of a flat plate with a coat of metal, can be an instrument for determination of the cladding thickness. An electromagnetic field from the coil is then forced to the object, producing eddy currents inside the object. These are influenced by the characteristics of the object and the coil and give rise to an impedance change, which can be detected and correlated to the thickness of the coating. An electromagnetic model accounting for the impedance of the elliptic coil with different values on the numerical eccentricity and the coating thickness is described. The model is based on a dyadic Green function formulation of the problem from which the electric field and hence the impedance is evaluated by utilizing the method of scattering super position. Numerical calculations based on the model and experimental measurements have been taken. An example shows how the model can be used to model a brass surface with a coat of silver to find expected impedance as function of the coating thickness

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-39222 (URN)10.1109/TIM.2007.894891 (DOI)47446 (Local ID)47446 (Archive number)47446 (OAI)
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2013-01-11
    3. Determination of the thickness of copper coatings on steel by measuring the impedance of a thin elliptic coil
    Open this publication in new window or tab >>Determination of the thickness of copper coatings on steel by measuring the impedance of a thin elliptic coil
    2002 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 13, no 4, 510-519 p.Article in journal (Refereed) Published
    Abstract [en]

    When a thin elliptically shaped coil is placed above a flat plate with a coat of metal, the magnetic fields in the vicinity of the coil is altered by eddy currents in the plate and the coat. The thickness of the coat influences the magnetic field and can be determined by measuring the coil impedance. An electromagnetic model utilizing an elliptic cylinder coordinate system accounting for the coil impedance with different values on the numerical eccentricity and the coating thickness is described. The model is based on a potential formulation of the problem from which the magnetic vector potential and hence the impedance is evaluated. The derivation utilizes a proper choice of the transversal field, giving a scalar Helmholtz equation in which the solution to the boundary value problem is separated. The resulting integral equation is expressed in closed form in terms of Mathieu functions. Numerical calculations and experimental measurements show how the model can be used to model a steel surface with a coat of copper to find expected impedance as function of the coating thickness.

    Keyword
    elliptic coil, thickness measuring, eddy current testing, coil impedance
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-48917 (URN)10.1088/0957-0233/13/4/313 (DOI)
    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2013-01-11
    4. Capacitive detection of humans for safety in industry: a numerical and experimental investigation
    Open this publication in new window or tab >>Capacitive detection of humans for safety in industry: a numerical and experimental investigation
    1998 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 9, no 3, 505-509 p.Article in journal (Refereed) Published
    Abstract [en]

    The detection of humans for their own safety in an industrial environment is vital, especially with increases in the flexibility and velocity of automated working machines. A capacitive detector for the detection of humans in guarded zones has been designed. An electromagnetic model accounting for bodies of different permittivity in the vicinity of the sensor is described. Numerical calculations based on the electromagnetic model have been made and experimental measurements have been taken. An example shows how the electromagnetic model can be used to model the output of the person detector.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-87164 (URN)10.1088/0957-0233/9/3/027 (DOI)
    Available from: 2013-01-11 Created: 2013-01-11 Last updated: 2013-01-11
  • 12.
    Ederth, Thomas
    et al.
    Phys and Theoret Chem Lab, Oxford OX1 3QZ, England.
    Thomas, R K
    Phys and Theoret Chem Lab, Oxford OX1 3QZ, England; .
    A neutron reflectivity study of drainage and stratification of AOT foam films2003In: Langmuir, ISSN 0743-7463, Vol. 19, no 19, 7727-7733 p.Article in journal (Refereed)
    Abstract [en]

    Structural properties of Aerosol-OT (AOT) foam films were studied by neutron reflectometry. The drainage of large (10 cm(2)), horizontally oriented AOT films under zero applied external pressure is slow and proceeds from thick colored or gray films to black films of approximately 200 Angstrom thickness over many hours, resulting in quasi-static conditions over the time scales required for the acquisition of reflectivity profiles throughout the whole drainage process. After formation of the foam film-while still showing colored interference fringes-and during the early stages of thinning, the appearance of Bragg diffraction peaks demonstrates that the film contains multilamellar structure, in agreement with studies at free air/water interfaces. Upon further reduction of the film thickness, below approximately 250 Angstrom, the reflectivity profile is well fitted by a three-layer slab model with two surfactant layers and an aqueous core with a high surfactant content. The composition of the aqueous core and the manner in which the reflectivity during the latter stages of draining evolves from Bragg peaks to a Kiessig fringe structure indicate stratification within the thin foam film.

  • 13.
    Mikhelashvili, V.
    et al.
    Technion Israel Institute Technology, Israel.
    Meyler, B.
    Technion Israel Institute Technology, Israel.
    Yofis, S.
    Technion Israel Institute Technology, Israel.
    Salzman, J.
    Technion Israel Institute Technology, Israel.
    Garbrecht, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Cohen-Hyams, T.
    Technion Israel Institute Technology, Israel.
    Kaplan, W. D.
    Technion Israel Institute Technology, Israel.
    Eisenstein, G.
    Technion Israel Institute Technology, Israel.
    A Nonvolatile Memory Capacitor Based on a Double Gold Nanocrystal Storing Layer and High-k Dielectric Tunneling and Control Layers2010In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 157, no 4, H463-H469 p.Article in journal (Refereed)
    Abstract [en]

    We present a metal-insulator-semiconductor nonvolatile memory capacitor based on two gold nanoparticle charge storage layers, two HfO(2) layers, and a multilayer HfNO/HfTiO stack. The device exhibits an equivalent oxide thickness of 7.3 nm, a hysteresis of 15 V at a gate voltage of +11 to -8 V, and a storage charge density of 2.75x10(13) cm(-2). A leakage of 3.6x10(-5) A/cm(2) at -10 V, a breakdown voltage of 13.3 V, and good retention properties with a hysteresis window of 10 V following more than 10 h of consecutive write/erase operations with a +/- 7 V swing were demonstrated. The capacitor characteristics are frequency-independent in the 10 kHz-1 MHz range.

  • 14.
    Danielsson, Pär
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Fredriksson, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Plastic Surgery, Hand Surgery and Burns. Linköping University, Faculty of Health Sciences.
    Huss, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    A Novel Concept for Treating Large Necrotizing Fasciitis Wounds With Bilayer Dermal Matrix, Split-thickness Skin Grafts, and Negative Pressure Wound Therapy2009In: Wounds (King of Prussia, Pa.), ISSN 1044-7946, Vol. 21, no 8, 215-220 p.Article in journal (Refereed)
    Abstract [en]

    Treatment of necrotizing fasciitis (NF) includes radical surgical debridement often resulting in large wounds that need to be closed with methods including split-thickness skin grafts (STSG), local flaps, or guided tissue regeneration procedures. In this case report, a 45 year-old Caucasian male was surgically treated for a benign left groin hernia, developed NF, and was transferred to the authors burn unit. The wound was treated initially with wide debridement and with a brief delay before finally closing the wound. A collagen matrix such as Integra (R) Dermal Regeneration Template (Integra LifeSciences, Plainsboro, NJ) in combination with STSG and negative pressure wound treatment, can provide fast recovery resulting in pliable, functional skin.

  • 15.
    Psoma, Sotiria D.
    et al.
    Cranfield University, Cranfield Health, Cranfield, Bedfordshire, UK.
    D. van der Wal, Peter
    EPFL, IMT-SAMLAB, Switzerland.
    Frey, Olivier
    EPFL, IMT-SAMLAB, Switzerland.
    de Rooij, Nicolaas F.
    EPFL, IMT-SAMLAB, Switzerland.
    Turner, Anthony P. F.
    Cranfield University, UK.
    A novel enzyme entrapment in SU-8 microfabricated films for glucose micro-biosensors2010In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 26, no 4, 1582-1587 p.Article in journal (Refereed)
    Abstract [en]

    The present work investigates the utilisation of the widely used SU-8 photoresist as an immobilisation matrix for glucose oxidase (GOx) for the development of glucose micro-biosensors. The strong advantage of the proposed approach is the simultaneous enzyme entrapment during the microfabrication process within a single step, which is of high importance for the simplification of the BioMEMS procedures. Successful encapsulation of the enzyme GOx in "customised" SU-8 microfabricated structures was achieved through optimisation of the one-step microfabrication process. Although the process involved contact with organic solvents, UV-light exposure, heating for pre- and post-bake and enzyme entrapment in a hard and rigid epoxy resin matrix, the enzyme retained its activity after encapsulation in SU-8. Measurements of the immobilised enzymes activity inside the SU-8 matrix were carried out using amperometric detection of hydrogen peroxide in a 3-electrode setup. Films without enzyme showed negligible variation in current upon the addition of glucose, as opposed to films with encapsulated enzyme which showed a very clear increase in current. Experiments using films of increased thickness or enzyme concentration, showed a higher response, thus proving that the enzyme remained active not only on the films surface, but also inside the matrix as well. The proposed enzyme immobilisation in SU-8 films opens up new possibilities for combining BioMEMS with biosensors and organic electronics.

  • 16.
    Broitman, Esteban
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Becker, Richard
    Studsvik Nuclear AB.
    Dozaki, Koji
    The Japan Atomic Power Company.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    A Novel Oxide Characterization Method of Nickel Base Alloy 600 Used in Nuclear Plant Reactors2013In: / [ed] F. Marquis, Hoboken, NJ, USA: John Wiley & Sons, 2013, 415- p.Conference paper (Refereed)
    Abstract [en]

    The Alloy 600 is a polycrystalline nickel base alloy used in pressurized water reactors (PWR) of nuclear power plants. Long term exposure of the alloy to primary water of PWR generates an oxide film that strongly influences the stress corrosion cracking behavior of the alloy. Recently, it has been shown that the oxide film structure, composition and thickness depend on the dissolved hydrogen content in the primary water. In this work we have explored a novel approach which enables a high spatial resolution oxide thickness measurement by nanomechanical testing. Oxide films have been grown on Alloy 600 specimens exposed between 5000 and 35000 hours at 320-330°C with hydrogen levels in the range 5 to 25 mL H2/kg H2O. A Triboindenter TI-950 from Hysitron was used to measure the change of nanomechanical properties in polished cross-sections. The increase of hardness has been correlated to the presence of oxides.

  • 17.
    Gustafsson, Mikael
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    A novel principle for quantitation of fast intracellular calcium changes using Fura-2 and a modified image processing system: applications in studies of neutrophil motility and phagocytosis1992In: Cell Calcium, ISSN 0143-4160, E-ISSN 1532-1991, Vol. 13, no 8, 473-486 p.Article in journal (Refereed)
    Abstract [en]

    A new principle is described for imaging intracellular free calcium [Ca2+]i changes in single, living cells utilizing the fluorescent probe Fura-2. It is based upon video color mixing in real time and allows high-speed visualization, at maximum image resolution, of [Ca2+]i changes without digital image ratioing. The epifluorescence images produced by 340 and 380 nm excitations are stored in two memory buffers of a personal computer-based image processing system. Two video signals are generated independently from each buffer and connected to the red and green inputs of a video display. An image is this way created, in which [Ca2+]i shows up as a specific hue, whereas changes in dye concentration, light intensity, cell thickness show up as variations in brightness of the imaged cells. The method has advantages over conventional ratio imaging, notably simplicity and speed, since no calculations are made. Yet it can be combined with traditional digital image processing. The imaging technique allows monitoring of [Ca2+]i changes in rapidly moving cells, like neutrophils. It is demonstrated that during random locomotion on serum-coated glass surfaces, [Ca2+]i levels appeared to oscillate and that the frequency of the oscillations are related to locomotive activity. Furthermore, in Ca2+ free medium, the cells continue to move and phagocytose in the presence of Ca2+ ionophore (ionomycin) and 2 mM EGTA. In the presence of 1 mM extracellular Ca2+, ionomycin-treated cells were not able to move or phagocytose.

  • 18.
    Johansson, Leif
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Virojanadara, Chariya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Eickhoff, T
    Hamburger Synchrotronstrahlungslabor HASYLAB am Deutschen Elektronen-Synchrotron DESY, Hamburg, Germany.
    Drube, W
    Hamburger Synchrotronstrahlungslabor HASYLAB am Deutschen Elektronen-Synchrotron DESY, Hamburg, Germany.
    A photoemission study of polar and non-polar SiC surfaces oxidized in N2O.2004In: SILICON CARBIDE AND RELATED MATERIALS 2003, PRTS 1 AND 2, Trans Tech Publications Inc., 2004, Vol. 457-460, 1329-1332 p.Conference paper (Refereed)
    Abstract [en]

    Angle resolved photoemission studies of SiO2/SiC samples grown ex situ in N2O on polar and non-polar 4H-SiC surfaces are reported. Data from the Si 1s and Si 2p core levels and the Si KL2,3L2,3 Auger transitions are analyzed and compared to data from a sample grown in O-2 on the (0001) surface. The results show oxide growth without nitride or oxy-nitride formation. Presence of two oxidation states, SiO2 and a sub-oxide explains recorded Si 1s. Si 2p and Si KLL spectra. Estimates of the oxide layer thickness show that the oxidation rate is highest for the (10 (1) under bar0) surface, somewhat smaller and similar for the (11 (2) under bar0) and (000 (1) under bar) surfaces, and smaller by a factor of about two for the (0001) surface.

  • 19.
    Usman Ali, Syed
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. NED University of Engineering and Technology, Pakistan.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Kashif, Muhammad
    University of Malaysia Perlis, Malaysia.
    Hashim, Uda
    University of Malaysia Perlis, Malaysia.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    A Potentiometric Indirect Uric Acid Sensor Based on ZnO Nanoflakes and Immobilized Uricase2012In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 12, no 3, 2787-2797 p.Article in journal (Refereed)
    Abstract [en]

    In the present work zinc oxide nanoflakes (ZnO-NF) structures with a wall thickness around 50 to 100 nm were synthesized on a gold coated glass substrate using a low temperature hydrothermal method. The enzyme uricase was electrostatically immobilized in conjunction with Nafion membrane on the surface of well oriented ZnO-NFs, resulting in a sensitive, selective, stable and reproducible uric acid sensor. The electrochemical response of the ZnO-NF-based sensor vs. a Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (500 nM to 1.5 mM). In addition, the ZnO-NF structures demonstrate vast surface area that allow high enzyme loading which results provided a higher sensitivity. The proposed ZnO-NF array-based sensor exhibited a high sensitivity of similar to 66 mV/ decade in test electrolyte solutions of uric acid, with fast response time. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea.

  • 20.
    Jennersjö, Pär
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Guldbrand, Hans
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, West County Primary Health Care.
    Björne, Stefan
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Thoracic and Vascular Surgery. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Fredrikson, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Lindström, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Endocrinology.
    Wijkman, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in East Östergötland, Department of Internal Medicine in Norrköping.
    Östgren, Carl Johan
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in West Östergötland, "Primary Health Care in Motala".
    Nyström, Fredrik H
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Endocrinology.
    A prospective observational study of all-cause mortality in relation to serum 25-OH vitamin D-3 and parathyroid hormone levels in patients with type 2 diabetes2015In: Diabetology and Metabolic Syndrome, ISSN 1758-5996, E-ISSN 1758-5996, Vol. 7, no 53Article in journal (Refereed)
    Abstract [en]

    Background: Low levels of vitamin D have been related to increased mortality and morbidity in several non-diabetic studies. We aimed to prospectively study relationships between serum 25-OH vitamin D-3 (vitamin D) and of serum parathyroid hormone (PTH) to total mortality in type 2 diabetes. We also aimed to compare the levels of these potential risk-factors in patients with and without diabetes. Methods: The main study design was prospective and observational. We used baseline data from 472 men and 245 women who participated in the "Cardiovascular Risk factors in Patients with Diabetes-a Prospective study in Primary care" study. Patients were 55-66 years old at recruitment, and an age-matched non-diabetic sample of 129 individuals constituted controls for the baseline data. Carotid-femoral pulse-wave velocity (PWV) was measured with applanation-tonometry and carotid intima-media thickness (IMT) with ultrasound. Patients with diabetes were followed for all-cause mortality using the national Swedish Cause of Death Registry. Results: Levels of vitamin D were lower in patients with diabetes than in controls, also after correction for age and obesity, while PTH levels did not differ. Nine women and 24 men died during 6 years of median follow up of the final cohort (n = 698). Vitamin D levels were negatively related to all-cause mortality in men independently of age, PTH, HbA1c, waist circumference, 24-h systolic ambulatory-blood pressure (ABP) and serum-apoB (p = 0.049). This finding was also statistically significant when PWV and IMT were added to the analyses (p = 0.028) and was not affected statistically when medications were also included in the regression-analysis (p = 0.01). In the women with type 2 diabetes, levels of PTH were positively related with all-cause mortality in the corresponding calculations (p = 0.016 without PWV and IMT, p = 0.006 with PWV and IMT, p = 0.045 when also adding medications to the analysis), while levels of vitamin D was without statistical significance (p greater than 0.9). Conclusions: Serum vitamin D in men and serum PTH in women give prognostic information in terms of total-mortality that are independent of regular risk factors in addition to levels of ABP, IMT and PWV.

  • 21.
    Ullman, Gustaf
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Sandborg, Michael
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    Dance, David R.
    Joint Department of Physics, The Royal Marsden NHS Trust, London, UK.
    Yaffe, Martin
    Department of Medical Biophysics, University of Toronto, Sunnybrook and Women's College Health Sciences Centre, Ontario, Canada.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences.
    A search for optimal x‐ray spectra in iodine contrast media mammography2005In: Physics in medicine and biology, ISSN 0031-9155, Vol. 50, no 13, 3143-3152 p.Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to search for the optimal x-ray tube voltage and anode–filter combination in digital iodine contrast media mammography. In the optimization, two entities were of interest: the average glandular dose, AGD, and the signal-to-noise ratio, SNR, for detection of diluted iodine contrast medium. The optimum is defined as the technique maximizing the figure of merit, SNR2/AGD. A Monte Carlo computer program was used which simulates the transport of photons from the x-ray tube through the compression plate, breast, breast support plate, anti-scatter grid and image detector. It computes the AGD and the SNR of an iodine detail inside the compressed breast. The breast thickness was varied between 2 and 8 cm with 10–90% glandularity. The tube voltage was varied between 20 and 55 kV for each anode material (Rh, Mo and W) in combination with either 25 µm Rh or 0.05–0.5 mm Cu added filtration. The x-ray spectra were calculated with MCNP4C (Monte Carlo N-Particle Transport Code System, version 4C). A CsI scintillator was used as the image detector. The results for Rh/0.3mmCu, Mo/0.3mmCu and W/0.3mmCu were similar. For all breast thicknesses, a maximum in the figure of merit was found at approximately 45 kV for the Rh/Cu, Mo/Cu and W/Cu combinations. The corresponding results for the Rh/Rh combination gave a figure of merit that was typically lower and more slowly varying with tube voltage. For a 4 cm breast at 45 kV, the SNR2/AGD was 3.5 times higher for the Rh/0.3mmCu combination compared with the Rh/Rh combination. The difference is even larger for thicker breasts. The SNR2/AGD increases slowly with increasing Cu-filter thickness. We conclude that tube voltages between 41 and 55 kV and added Cu-filtration will result in significant dose advantage in digital iodine contrast media mammography compared to using the Rh/Rh anode/filter combination at 25–32 kV.

  • 22. Liu, Yuwen
    et al.
    Gan, Lisha
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Ophthalmology.
    Carlsson, David J
    Fagerholm, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Ophthalmology. Östergötlands Läns Landsting, Reconstruction Centre, Department of Ophthalmology UHL.
    Lagali, Neil
    University of Ottawa.
    Watsky, Mitchell A
    Munger, Rejean
    Hodge, William G
    Priest, David
    Griffith, May
    A simple, cross-linked collagen tissue substitute for corneal implantation2006In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, Vol. 47, no 5, 1869-1875 p.Article in journal (Refereed)
    Abstract [en]

    PURPOSE. To develop a simple corneal substitute from crosslinked collagen. METHODS. Porcine type I collagen (10%, pH 5), was mixed with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The final homogenous solution was molded to corneal dimensions, cured, and then implanted into rabbits and minipigs by lamellar keratoplasty. The implants were followed for up to 6 months after surgery. Clinical examinations of the cornea included detailed slit lamp biomicroscopy, in vivo confocal microscopy, topography and esthesiometry for nerve function. Histopathologic examinations were also performed on rabbit corneas harvested after 6 months. RESULTS. Cross-linked collagen (refractive index, 1.35) had optical clarity superior to human corneas. Implanted into rabbit and porcine corneas, only 1 of 24 of the surgical corneas showed a slight haze at 6 months after surgery. All other implants showed no adverse reactions and remained optically clear. Topography showed a smooth surface and a profile similar to that of the contralateral nonsurgical eye. The implanted matrices promoted regeneration of corneal cells, tear film, and nerves. Touch sensitivity was restored, indicating some restoration of function. The corneas with implants showed no significant loss of thickness and demonstrated stable host- graft integration. CONCLUSIONS. Collagen can be adequately stabilized, using water soluble carbodiimides as protein cross-linking reagents, in the fabrication of corneal matrix substitutes for implantation. The simple cross-linking methodology would allow for easy fabrication of matrices for transplantation in centers where there is a shortage of corneas, or where there is need for temporary patches to repair perforations in emergency situations. Copyright © Association for Research in Vision and Ophthalmology.

  • 23.
    Lindström, Jan
    et al.
    Radiation Physics Department, Borås Hospital, Borås.
    Alm Carlsson, Gudrun
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    A simple model for estimating the particle size dependence of absolute efficiency of fluorescent screens1999In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 44, no 5, 1353-67 p.Article in journal (Refereed)
    Abstract [en]

    The absolute efficiency of a phosphor screen is the ratio of the light energy per unit area at the screen surface to the incident x-ray energy fluence. Particle size is a critical factor in determining the absolute efficiency, but in most models its influence is not accounted for. To allow derivation of the particle size dependence, a model is proposed that describes the optical properties of the screen by means of a single parameter, the light extinction factor, xi, and assumes that the intrinsic efficiency (light energy/energy imparted to the phosphor material) is independent of particle size. The value of xi depends on the type of screen (phosphor, reflective backing, coating and binder) and has to be determined from measurements on at least two screens with known particle size and thickness. The absolute efficiency can then be calculated for an extended range of particle sizes and/or screen thicknesses. To test the model, experimental data from the literature were used to derive values of xi for screens of La2O2S:Tb, LaOBr:Tm and ZnCdS:Ag. The extinction factor was found to vary between -6 and +20%. The non-physical negative value for xi, found from one set of experiments on La2O2S:Tb screens, may be explained as resulting from a lack of accurate knowledge of the actual tube potential, influencing calculated values of the energy imparted to the screen. The results are promising but further well-controlled experiments (including improved dosimetric calculations to account forescape of K-radiation from the screen) are needed to confirm the model.

  • 24.
    Brändström, H.
    et al.
    Department of Medical Sciences, Uppsala University, Sweden.
    Stiger, F.
    Department of Medical Sciences, Uppsala University, Sweden.
    Kahan, T.
    Division of Internal Medicine, Karolinska Institutet, Danderyd Hospital, Stockholm, Sweden.
    Melhus, H.
    Department of Medical Sciences, Uppsala University, Sweden.
    Nyström, Fredrik
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Öhman, K.P.
    Linköping University, Department of Medicine and Care. Linköping University, Faculty of Health Sciences. Departments of Experimental and Clinical Science, Astra Zeneca R&D Mölndal, Sweden.
    Malmqvist, K.
    Division of Internal Medicine, Karolinska Institutet, Danderyd Hospital, Stockholm, Sweden.
    Lind, L.
    Department of Medical Sciences, Uppsala University, Sweden.
    Kindmark, A.
    Department of Medical Sciences, Uppsala University, Sweden and Departments of Experimental and Clinical Science, Astra Zeneca R&D Mölndal, Sweden.
    A single nucleotide polymorphism in the promoter region of the osteoprotegerin gene is related to intima-media thickness of the carotid artery in hypertensive patients. The Swedish Irbesartan Left Ventricular Hypertrophy Investigation vs Atenolol (SILVHIA)2004In: Blood Pressure, ISSN 0803-7051, Vol. 13, no 3, 152-157 p.Article in journal (Refereed)
    Abstract [en]

    Osteoprotegerin (OPG) is a secreted member of the tumor necrosis factor receptor family, and in previous studies has been shown to regulate osteoclast activity and differentiation. Ablation of the OPG gene in mice results in calcification of the aorta and renal arteries. We have previously reported an association between a single nucleotide polymorphism in the promoter region of OPG and vascular morphology and function in healthy humans. The objective with this study was to confirm our previous results in a larger population, and in addition, to study subjects with hypertension. The OPG genotype was determined by restriction fragment length and the intima-media thickness (IMT) of the common carotid artery was measured by ultrasound in 100 patients with hypertension and left ventricular hypertrophy, and 75 healthy normotensive control subjects. In the hypertensive group subjects with the CC genotype (n = 24) showed a significantly increased IMT compared to those with the TC (n = 52, p = 0.007) and TT (n = 24, p = 0.009) genotype, in the hypertensive group only (mean ± SD for TT = 0.88 ± 0.21 mm, TC = 0.90 ± 0.16 mm, CC = 1.05 ± 0.31 mm). The allele distribution did not differ between hypertensive and control individuals. The present study confirms our previous finding and shows that polymorphism in the promoter region of OPG is associated with vascular morphology in hypertensive subjects. © 2004 Taylor & Francis on licence from Blood Pressure.

  • 25.
    Björnsson Hallgren, Hanna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics. Linköping University, Faculty of Health Sciences.
    Holmgren, Theresa
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    Öberg, Birgitta
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    Johansson, Kajsa
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    Adolfsson, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    A specific exercise strategy for patients with subacromial pain significantly reduced the need for surgery: one-year results of a randomised controlled studyManuscript (preprint) (Other academic)
    Abstract [en]

    Background: A specific exercise strategy focusing on eccentric exercises, for treating sbacromial pain has in a previous study been found effective at three-month followup.

    The aim of the present study was to investigate if the positive short-term results were maintained after one year. A further aim was to examine if baseline clinical score, rotator cuff status and radiological findings influenced the choice of surgery.

    Methods: 97 patients on the waiting-list for arthroscopic subacromial decompression were in the first study randomized to a three-month specific exercise strategy or unspecific exercises (controls). Patients were examined with radiology, ultrasound and assessed with clinical scores: primary Constant-Murley score. After three months of exercises the patients were asked if they still wanted surgery and this option was available until the one-year follow-up. All patients were re-assessed with clinical scores one year after inclusion or one year after surgical intervention and the number of patients that had chosen surgery in each group was compared. The baseline Constant-Murley score and the status of subacromial structures were analyzed in relation to patient's choice of surgery.

    Results: The positive short-term effect (improved shoulder function and pain) of the specific exercises was maintained after one-year. Compared to the three-month followup all patients had improved significantly (p < 0.0001) in Constant-Murley score. The number of patients that had chosen surgery in the control exercise group (63%) was significantly larger (p < 0.0001) than in the specific exercise group (24%). Patients that had chosen surgery had a significantly lower baseline Constant-Murley score and significantly more often a full-thickness tear. Patients with partial-thickness tears did not differ from those with intact cuff tendons.

    Conclusions: The positive short-term outcomes after specific exercises were maintained after one year and reduced the need of surgery significantly more than the unspecific control exercises. Patients with low baseline clinical score and/or a full-thickness tear significantly more often chose surgery.

    Level of evidence: I, Randomized controlled trail according to Consort statement.

  • 26.
    Björnsson Hallgren, Hanna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Holmgren, Theresa
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Health Sciences.
    Öberg, Birgitta
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Health Sciences.
    Johansson, Kajsa
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Health Sciences.
    Adolfsson, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    A specific exercise strategy reduced the need for surgery in subacromial pain patients2014In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 48, no 19, 1431-1436 p.Article in journal (Refereed)
    Abstract [en]

    Background and purpose A programme based on eccentric exercises for treating subacromial pain was in a previous study found effective at 3-month follow-up. The purposes of the present study were to investigate whether the results were maintained after 1 year and whether the baseline Constant-Murley score, rotator cuff status and radiological findings influenced the outcome. Patients and methods 97 patients on the waiting list for arthroscopic subacromial decompression had been randomised to a specific exercise programme or unspecific exercises (controls). After 3 months of exercises, the patients were asked whether they still wanted surgery and this option was available until a 1-year follow-up. 1 year after inclusion or 1 year after surgery, the number of patients who decided to have surgery in each group was compared. The choice of surgery was related to the baseline Constant-Murley score, ultrasound and radiographs taken at inclusion. Results All patients had improved significantly (pless than0.0001) in the Constant-Murley score at the 1-year follow-up. Significantly more patients in the control group decided to have surgery (63%) than those in the specific exercise group (24%; pless than0.0001). Patients who decided to have surgery had a significantly lower baseline Constant-Murley score and more often a full-thickness tear. Patients with partial tears did not differ from those with intact tendons. Interpretation The positive short-term results of specific exercises were maintained after 1 year, and this exercise strategy reduces the need for surgery. Full-thickness tear and a low baseline Constant-Murley score appear to be a predictive marker for a less good outcome.

  • 27.
    Johansson, Anders
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Sundqvist, Tommy
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Kuiper, J.-H.
    Keele University School of Medicine, Keele, UK .
    Öberg, Åke
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    A spectroscopic approach to imaging and quantification of cartilage lesions in human knee joints2011In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 56, no 6, 1865-1878 p.Article in journal (Refereed)
    Abstract [en]

    We have previously described a technology based on diffuse reflectance of broadband light for measuring joint articular cartilage thickness, utilizing that optical absorption is different in cartilage and subchondral bone. This study is the first evaluation of the technology in human material. We also investigated the prospects of cartilage lesion imaging, with the specific aim of arthroscopic integration. Cartilage thickness was studied ex vivo in a number of sites (n = 87) on human knee joint condyles, removed from nine patients during total knee replacement surgery. A reflectance spectrum was taken at each site and the cartilage thickness was estimated using the blue, green, red and near-infrared regions of the spectrum, respectively. Estimated values were compared with reference cartilage thickness values (taken after sample slicing) using an exponential model. Two-dimensional Monte Carlo simulations were performed in a theoretical analysis of the experimental results. The reference cartilage thickness of the investigated sites was 1.60 ± 1.30 mm (mean ± SD) in the range 0–4.2 mm. Highest correlation coefficients were seen for the calculations based on the near-infrared region after normalization to the red region (r = 0.86) and for the green region (r = 0.80).

  • 28.
    Vicente, Antonio T.
    et al.
    University of Nova Lisboa, Portugal; CEMOP UNINOVA, Portugal.
    Wojcik, Pawel
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. University of Nova Lisboa, Portugal; CEMOP UNINOVA, Portugal.
    Mendes, Manuel J.
    University of Nova Lisboa, Portugal; CEMOP UNINOVA, Portugal.
    Aguas, Hugo
    University of Nova Lisboa, Portugal; CEMOP UNINOVA, Portugal.
    Fortunato, Elvira
    University of Nova Lisboa, Portugal; CEMOP UNINOVA, Portugal.
    Martins, Rodrigo
    University of Nova Lisboa, Portugal; CEMOP UNINOVA, Portugal.
    A statistics modeling approach for the optimization of thin film photovoltaic devices2017In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 144, 232-243 p.Article in journal (Refereed)
    Abstract [en]

    The growing interest in exploring thin film technologies to produce low cost devices such as n-i-p silicon solar cells, with outstanding performances and capability to address the highly relevant energy market, turns the optimization of their fabrication process a key area of development. The usual one-dimensional analysis of the involved parameters makes it difficult and time consuming to find the optimal set of conditions. To overcome these difficulties, the combination of experimental design and statistical analysis provides the tools to explore in a multidimensional fashion the interactions between fabrication parameters and expected experimental outputs. Design of Experiment and Multivariate Analysis are demonstrated here for the optimization of: (1) the low temperature deposition (150 degrees C) of high quality intrinsic amorphous silicon (i-a-Si:H); and (2) the matching of the n-, i-, and p-silicon layers thickness to maximize the efficiency of thin film solar cells. The multiple regression method applied, validated through analysis of variance and evaluated against exact numerical simulations, is shown to predict the overall intrinsic layer properties and the devices performance. The results confirm that experimental design and statistical data analysis are effective approaches to improve, within a minimum time frame and high certainty, the properties of silicon thin films, and subsequently the layer structure of solar cells.(C) 2017 Published by Elsevier Ltd.

  • 29.
    Carlsson, Karin
    Linköping University, Department of Management and Engineering.
    A Study of Failure Development in Thick Thermal Barrier Coatings2007Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    Thermal barrier coatings (TBC) are used for reduction of component temperatures in gas turbines. The service temperature for turbines can be as high as 1100ºC and the components are exposed to thermal cycling and gases that will cause the component to oxidize and corrode. The coatings are designed to protect the substrate material from this, but eventually it will lead to failure of the TBC. It is important to have knowledge about when this failure is expected, since it is detrimental for the gas turbine.

    The scope of this thesis has been to see if an existing life model for thin TBC also is valid for thick TBC. In order to do so, a thermal cycling fatigue test, a tensile test and finite element calculation have been performed. The thermal cycling fatigue test and finite element calculation were done to find correlations between the damage due to thermal cycling, the number of thermal cycles and the energy release rate. The tensile test was preformed to find the amount accumulated strain until damage.

    The thermal cycling lead to failure of the TBC at the bond coat/top coat interface. The measurment of damage, porosity and thickness of thermally grown oxide were unsatisfying due to problems with the specimen preparation. However, a tendency for the damage development were seen. The finite element calculations gave values for the energy release rate the stress intensity factors in mode~I and mode~II that can be used in the life model. The tensile test showed that the failure mechanism is dependent of the coating thickness and it gave a rough value of the maximum strain acceptable.

  • 30.
    Lebedev, Alexander
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Zelenin, V.V.
    Abramov, P.L.
    Bogdanova, E.V.
    Lebedev, S.P.
    Nel¿son, D.K.
    Razbirin, B.S.
    Shcheglov, M.P.
    Tregubova, A.S.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    A study of thick 3C-SiC epitaxial layers grown on 6H-SiC substrates by sublimation epitaxy in vacuum2007In: Semiconductors (Woodbury, N.Y.), ISSN 1063-7826, Vol. 41, no 3, 263-265 p.Article in journal (Refereed)
    Abstract [en]

    3C-SiC epitaxial layers with a thickness of up to 100 μm were grown on 6H-SiC hexagonal substrates by sublimation epitaxy in vacuum. The n-type epitaxial layers with the area in the range 0.3-0.5 cm2 and uncompensated donor concentration N d - N a ∼ (10 17-1018) cm-3 were produced at maximum growth rates of up to 200 μm/h. An X-ray analysis demonstrated that the epitaxial layers are composed of the 3C-SiC polytype, without inclusions of other polytypes. The photoluminescence (PL) spectrum of the layers was found to be dominated by the donor-acceptor (Al-N) recombination band peaked at hv ≈ 2.12 eV. The PL spectrum measured at 6 K was analyzed in detail. It is concluded that the epitaxial layers obtained can serve as substrates for 3C-SiC-based electronic devices. © Nauka/Interperiodica 2007.

  • 31.
    Sarri, Gianluca
    et al.
    Queen's University Belfast, Northern Ireland, UK.
    Schumaker, W.
    University of Michigan, USA.
    Di Piazza, A.
    Max-Planck-Institut für Kernphysik, Heidelberg, Germany.
    Vargas, M.
    University of Michigan, USA.
    Dromey, Brendan
    University of Michigan, USA.
    Dieckmann, Mark Eric
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Queen's University Belfast, Northern Ireland, UK.
    Chvykov, V.
    University of Michigan, USA.
    Maksimchuk, A.
    University of Michigan, USA.
    Yanovsky, V.
    University of Michigan, USA.
    He, ZH
    University of Michigan, USA.
    Hou, BX
    University of Michigan, USA.
    Nees, J.A.
    University of Michigan, USA.
    Thomas, A.G.R.
    University of Michigan, USA.
    Keitel, C.H.
    University of Michigan, USA.
    Zepf, Matt
    Queen's University Belfast, Northern Ireland, UK.
    Krushelnick, K.
    University of Michigan, USA.
    A table-top laser-based source of short, collimated, ultra-relativistic positron beams2013In: Laser Acceleration of Electrons, Protons, and Ions II; and Medical Applications of Laser-Generated Beams of Particles II; and Harnessing Relativistic Plasma Waves III / [ed] Eric Esarey, SPIE - International Society for Optical Engineering, 2013, 87790Z-1-87790Z-7 p.Conference paper (Refereed)
    Abstract [en]

    An ultra-relativistic electron beam passing through a thick, high-Z solid target triggers an electromagnetic cascade, whereby a large number of high energy photons and electron-positron pairs are produced. By exploiting this physical process, we present here the first experimental evidence of the generation of ultra-short, highly collimated and ultra-relativistic positron beams following the interaction of a laser-wakefield accelerated electron beam with high-Z solid targets. Clear evidence has also been obtained of the generation of GeV electron-positron jets with variable composition depending on the solid target material and thickness. The percentage of positrons in the overall leptonic beam has been observed to vary from a few per cent up to almost fifty per cent, implying a quasi-neutral electron-positron beam. We anticipate that these beams will be of direct relevance to the laboratory study of astrophysical leptonic jets and their interaction with the interstellar medium

  • 32.
    Dahlén, Elsa M
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Clinchy, Birgitta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Ernerudh, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Nyström, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology.
    Östgren, Carl Johan
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, West County Primary Health Care.
    Abdominal Obesity and low grade Systemic Inflammation as Markers for Subclinical Organ Damage in type 2 diabetes2014In: Diabetes & Metabolism, ISSN 1262-3636, Vol. 40, no 1, 76-81 p.Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to explore associations between abdominal obesity, inflammatory markers, and subclinical organ damage in 740 patients with type 2 diabetes. Waist circumference (WC) and sagittal abdominal diameter (SAD) was measured. Blood samples were analyzed for; C-reactive protein (CRP), interleukin (IL) -1β and IL-6. Carotid intimamedia thickness (IMT) was evaluated by ultrasonography. Aortic pulse wave velocity (PWV) was measured with applanation tonometry.

    Abdominal obesity were significantly correlated with; IL-6, CRP (both p= <0.001, WC and SAD, respectively), IMT (WC p=0.012, SAD p=0.003) and PWV (p<0.001, for WC and SAD, respectively). In multiple linear regressions with IMT as dependent variable and age, sex, statins, systolic blood pressure (SBP), Body Mass Index (BMI), CRP and HbA1c, as independent variables, SAD (p=0.047) but not WC, remained associated with IMT. In stepwise linear regression, entering both SAD and WC, the association between SAD and PWV was stronger than the association between WC and PWV.

    We conclude that SAD and WC are feasible measures of obesity that provides information on inflammation, atherosclerosis and arterial stiffness in type 2 diabetes. However, SAD was slightly more robustly associated to subclinical organ damage, compared with WC.

  • 33.
    Fallqvist, Amie
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Aberration-Corrected Analytical Electron Microscopy of Transition Metal Nitride and Silicon Nitride Multilayers2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Two multilayer thin films have been studied: TiN/SiNx and ZrN/SiNx. A double-corrected transmission electron microscope (TEM) was utilized for imaging and spectroscopy. Imaging was carried out in scanning mode (STEM) for all samples. Energy dispersive X-ray (EDX) spectrometry was used for chemical mapping of the ZrN/SiNx samples and electron energy loss spectrometry (EELS) for atomic coordination of the nitrogen in the TiN/SiNx samples.

    In the TiN/SiNx multilayer the structure of the epitaxially stabilized cubic SiNx was investigated. The high-resolution STEM images were compared with image simulations of SiNx in B1 (sodium chloride) and B3 (zinc blende) configurations and were found to be most similar to the B1 configuration. Core-loss EEL spectra were compared with calculated spectra and corroborated a resemblance with the B1 configuration.

    The ZrN/SiNx multilayers were initially believed to show a similarity to TiN/SiNx but further investigations with STEM showed that the SiNx is amorphous. For samples deposited at 800 °C a SiNx layer thickness ≤6 Å the SiNx forms precipitates at grain boundaries and surface defects of the ZrN resulting in a columnar distribution of the SiNx, which was further revealed by EDX. For such samples the ZrN grows by epitaxial lateral overgrowth. For samples deposited at 800 °C but with a SiNx layer thickness of 6 Å the SiNx starts to form more laterally extending layers and for thicknesses ≥8 Å the SiNx grows into continuous, amorphous layers causing the following ZrN layers to assume a polycrystalline microstructure. The transition from epitaxial ZrN with columnar, amorphous SiNx, to multilayers of polycrystalline ZrN and amorphous SiNx layers appears at an even smaller thickness of SiNx if the  deposition temperature is lowered, which is explained by the lowered adatom mobility.

    List of papers
    1. Evidence for B1-cubic SiNx by Aberration-Corrected Analytical STEM
    Open this publication in new window or tab >>Evidence for B1-cubic SiNx by Aberration-Corrected Analytical STEM
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The crystal structure of epitaxially stabilized SiNx layers on TiN(001) was investigated by analytical aberration corrected electron microscopy. Atomically resolved images of the structure, which were acquired by scanning transmission electron microscopy using high angle annular dark field and annular bright field detectors, are used to identify the B1-cubic structure of SiNx. To corroborate the acquired images, image simulations were performed using candidate structures. Complementary to imaging, spatially resolved electron energy loss spectroscopy of the epitaxial SiNx layers was performed to acquire the symmetry specific nitrogen near edge fine-structure. Finally, full potential calculations performed to determine the near edge structure from candidate crystal structures confirms the existence of B1-cubic SiNx.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-102172 (URN)
    Available from: 2013-12-02 Created: 2013-12-02 Last updated: 2016-08-31Bibliographically approved
    2. Self-organization during Growth of ZrN/SiNx Multilayers by Epitaxial Lateral Overgrowth
    Open this publication in new window or tab >>Self-organization during Growth of ZrN/SiNx Multilayers by Epitaxial Lateral Overgrowth
    Show others...
    2013 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 114, no 224302Article in journal (Refereed) Published
    Abstract [en]

    ZrN/SiNx nanoscale multilayers were deposited on ZrN seed layers grown on top of MgO(001) substrates by dc magnetron sputtering with a constant ZrN thickness of 40 Å and with an intended SiNx thickness of 2, 4, 6, 8, and 15 Å at a substrate temperature of 800 °C and 6 Å at 500 °C. The films were investigated by X-ray diffraction, high-resolution scanning transmission electron microscopy, and energy dispersive X-ray spectroscopy. The investigations show that the SiNx is amorphous and that the ZrN layers are crystalline. Growth of epitaxial cubic SiNx – known to take place on TiN(001) – on ZrN(001) is excluded to the monolayer resolution of this study. During the course of SiNx deposition, the material segregates to form surface precipitates in discontinuous layers for SiNx thicknesses ≤ 6 Å that coalesce into continuous layers for 8 and 15 Å thickness at 800 °C, and for 6 Å at 500 °C. The SiNx precipitates are aligned vertically. The ZrN layers in turn grow by epitaxial lateral overgrowth on the discontinuous SiNx in samples deposited at 800 °C with up to 6 Å thick SiNx layers. Effectively a self-organized nanostructure can be grown consisting of strings of 1-3 nm large SiNx precipitates along apparent column boundaries in the epitaxial ZrN.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-102173 (URN)10.1063/1.4838495 (DOI)000329090400072 ()
    Available from: 2013-12-02 Created: 2013-12-02 Last updated: 2016-08-31Bibliographically approved
  • 34.
    Lee, Chih Feng
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Manzie, Chris
    University of Melbourne, Australia.
    Active Brake Judder Attenuation Using an Electromechanical Brake-by-Wire System2017In: IEEE/ASME transactions on mechatronics, ISSN 1083-4435, E-ISSN 1941-014X, Vol. 21, no 6, 2964-2976 p.Article in journal (Refereed)
    Abstract [en]

    Brake judder is an undesirable phenomenon in passenger vehicles whereby disk thickness variations lead to brake torque variations (BTVs) during light braking events with a consequence of reduced braking performance and driver satisfaction. Most solutions involve passive approaches; however, in this study, a novel active brake judder attenuation strategy utilizing the capabilities of a prototype electromechanical brake (EMB) is proposed. Two attenuation algorithms with different sensor requirements are presented, where compensating clamp force commands are generated to cancel the judder causing BTV arises during light braking. The first approach is founded on the linear parameter-varying (LPV) control structure, which is designed using the output regulation theory and scheduled using wheel angular speed and acceleration. The second approach examines the adaptive feedforward compensation, where the compensator is scheduled using wheel angular position, speed, and acceleration. Experimental investigations showed favorable results for the LPV compensator, albeit with high sampling rate requirements. On the other hand, the adaptive compensator demonstrated lower sampling rate requirements with better BTV attenuation, but required wheel position measurements. These results highlight the applicability of EMBin judder reduction and the advantage of having wheel measurements.

  • 35.
    Wijkman, Magnus
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Acute, ambulatory and central blood pressure measurements in diabetes2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: In patients with diabetes, high blood pressure is an established risk factor for cardiovascular disease. The aim of this thesis was to explore the associations between blood pressure levels measured with different techniques and during different circumstances, and the degree of cardiovascular organ damage and subsequent prognosis in patients with diabetes.

    Methods: We analysed baseline data from patients with type 2 diabetes who participated in the observational cohort study CARDIPP (Cardiovascular Risk factors in Patients with Diabetes – a Prospective study in Primary care), and longitudinal data from patients registered in the Swedish national quality registry RIKS-HIA (Register of Information and Knowledge about Swedish Heart Intensive care Admissions). Patients in CARDIPP underwent nurse-recorded, 24-hour ambulatory and non-invasive central blood pressure measurements. Patients in RIKS-HIA had their systolic blood pressure measured upon hospitalisation for acute chest pain.

    Results: In CARDIPP, nearly one in three patients with office normotension (<130/80 mmHg) were hypertensive during the night (≥120/70 mmHg). This phenomenon, masked nocturnal hypertension, was significantly associated with increased arterial stiffness and increased central blood pressure. Furthermore, nearly one in five CARDIPP patients with office normotension had high central pulse pressure (≥50 mmHg), and there was a significant association between high central pulse pressure and increased carotid intima-media thickness and increased arterial stiffness. Among CARDIPP patients who used at least one antihypertensive drug, those who used beta blockers had significantly higher central pulse pressure than those who used other antihypertensive drugs, but there were no significant between-group differences concerning office or ambulatory pulse pressures. In CARDIPP patients with or without antihypertensive treatment, ambulatory systolic blood pressure levels were significantly associated with left ventricular mass, independently of central systolic blood pressure levels. When RIKS-HIA patients, admitted to hospital for chest pain, were stratified in quartiles according to admission systolic blood pressure levels, the risk for all-cause one-year mortality was significantly lower in patients with admission systolic blood pressure in the highest quartile (≥163 mmHg) than in patients with admission systolic blood pressure in the reference quartile (128-144 mmHg). This finding remained unaltered when the analysis was restricted to include only patients with previously known diabetes.

    Conclusions: In patients with type 2 diabetes, ambulatory or central blood pressure measurements identified patients with residual risk factors despite excellent office blood pressure control or despite ongoing antihypertensive treatment. Ambulatory systolic blood pressure predicted left ventricular mass independently of central systolic blood pressure. In patients with previously known diabetes who were hospitalised for acute chest pain, there was an inverse relationship between systolic blood pressure measured at admission and the risk for one-year all-cause mortality.

    List of papers
    1. Masked nocturnal hypertension - a novel marker of risk in type 2 diabetes.
    Open this publication in new window or tab >>Masked nocturnal hypertension - a novel marker of risk in type 2 diabetes.
    Show others...
    2009 (English)In: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 52, no 7, 1258-64 p.Article in journal (Refereed) Published
    Abstract [en]

    AIMS/HYPOTHESIS: This study was designed to evaluate the prevalence of masked nocturnal hypertension (MNHT) and its impact on arterial stiffness and central blood pressure in patients with type 2 diabetes. METHODS: Middle-aged patients (n = 414) with type 2 diabetes underwent clinic and ambulatory BP measurements and applanation tonometry. RESULTS: MNHT (clinic BP < 130/80 mmHg and night-time BP > or = 120/70 mmHg) was found in 7.2% of patients (n = 30). Compared with patients with both clinical and nocturnal normotension (n = 70), patients with MNHT had higher aortic pulse wave velocity (PWV) (10.2 +/- 1.8 m/s vs 9.4 +/- 1.7 m/s; p = 0.03) and higher central BP (117.6 +/- 13.9/74.0 +/- 9.1 mmHg vs 110.4 +/- 16.4/69.7 +/- 9.6 mmHg, p = 0.04). In patients with clinical normotension, night-time systolic BP correlated significantly with PWV. CONCLUSIONS/INTERPRETATION: Thirty per cent of patients with clinical normotension had nocturnal hypertension. This was accompanied by increased arterial stiffness and higher central BP. We conclude that in clinically normotensive patients with type 2 diabetes, ambulatory BP measurement may help clinicians to identify patients with increased cardiovascular risk.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-18981 (URN)10.1007/s00125-009-1369-9 (DOI)19396423 (PubMedID)
    Available from: 2009-06-07 Created: 2009-06-07 Last updated: 2017-03-27Bibliographically approved
    2. Association between admission supine systolic blood pressure and 1-year mortality in patients admitted to the intensive care unit for acute chest pain.
    Open this publication in new window or tab >>Association between admission supine systolic blood pressure and 1-year mortality in patients admitted to the intensive care unit for acute chest pain.
    2010 (English)In: Journal of the American Medical Association (JAMA), ISSN 0098-7484, E-ISSN 1538-3598, Vol. 303, no 12, 1167-1172 p.Article in journal (Refereed) Published
    Abstract [en]

    CONTEXT: High resting blood pressure (BP) is among the best studied and established risk factors for cardiovascular disease. However, little is known about the relationship between BP under acute stress, such as in acute chest pain, and subsequent mortality. OBJECTIVE: To study long-term mortality related to supine BP in patients admitted to the medical intensive care unit (ICU) for acute chest pain. DESIGN, SETTING, AND PARTICIPANTS: Data from the RIKS-HIA (Registry of Information and Knowledge About Swedish Heart Intensive Care Admissions) was used to analyze the mortality in relation to supine admission systolic BP in 119,151 participants who were treated at the ICU for the symptom of chest pain from 1997 through 2007. Results from this prospective cohort study were presented according to systolic BP quartiles: Q1, less than 128 mm Hg; Q2, from 128 to 144 mm Hg; Q3, from 145 to 162 mm Hg; and Q4, at or above 163 mm Hg. MAIN OUTCOME MEASURE: Total mortality. RESULTS: Mean (SD) follow-up time was 2.47 (1.5) years (range, 1-10 years). One-year mortality rate by Cox proportional hazard model (adjusted for age, sex, smoking, diastolic BP, use of antihypertensive medication at admission and discharge, and use of lipid-lowering and antiplatelet medication at discharge) showed that participants in Q4 had the best prognosis (hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.72-0.80, Q4 compared with Q2; corresponding risks for Q1 were HR, 1.46; 95% CI, 1.39-1.52, and for Q3, HR, 0.83; 95% CI, 0.79-0.87). Patients in Q4 had a 21.7% lower absolute risk compared with Q2, patients in Q3 had a 15.2% lower risk than in Q2, and patients in Q1 had a 40.3% higher risk for mortality than in Q2. The worse prognosis in Q2 compared with Q4 was independent of body mass index and previous diagnoses and similar when analysis was restricted to patients with a final diagnosis of angina or myocardial infarction (HR, 0.75; 95% CI, 0.71-0.80, Q4 compared with Q2). CONCLUSION: Among patients admitted to the ICU for chest pain, there is an inverse association between admission supine systolic BP and 1-year mortality rate.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-58765 (URN)10.1001/jama.2010.314 (DOI)20332402 (PubMedID)
    Available from: 2010-08-26 Created: 2010-08-26 Last updated: 2013-09-10
    3. ß-blocker Treatment is Associated with High Augmentation Index and with High Aortic, but not Brachial, Pulse Pressure in Type 2 Diabetes
    Open this publication in new window or tab >>ß-blocker Treatment is Associated with High Augmentation Index and with High Aortic, but not Brachial, Pulse Pressure in Type 2 Diabetes
    Show others...
    2010 (English)In: The journal of clinical metabolism and diabetes, Vol. 1, no 1, 55-62 p.Article in journal (Refereed) Published
    Abstract [en]

    Aims: To explore the associations between ß-blocker treatment and clinic, ambulatory, and central pulse pressure (PP) and central augmentation index (AIx), and left ventricular mass index (LVMI), respectively, in patients with type 2 diabetes.Methods: In 124 middle-aged patients with type 2 diabetes who were treated in primary care and used at least one antihypertensive drug, we measured clinic PP (mean value of three nurse-recorded measurements in the sitting position) and ambulatory PP (24-hour ambulatory measurements with the Spacelab 90217 measurement device). Central PP was measured non-invasively, using applanation tonometry (SphygmoCor), which also yielded values of AIx. LVMI was determined echocardiographically in all patients.Results: Patients whose antihypertensive drug regimen included a ß-blocker (n=67) had significantly higher central PP compared with patients whose antihypertensive drug regimen did not include a ß-blocker (ß-blocker: 49.6±12.2 mmHg, no ß-blocker: 45.1±10.2 mmHg; p=0.03) despite having similar clinic PP (ß-blocker: 60.4±16.3 mmHg, no ß-blocker: 58.9±13.1 mmHg; p=0.59) and similar ambulatory PP (ß-blocker: 55.2±9.1 mmHg, no ß-blocker: 54.8±10.6 mmHg; p=0.40). Patients treated with ß-blockers also had significantly higher AIx (ß-blocker: 30.7±8.4%, no ß-blocker: 25.8±8.8%; p<0.01) and higher LVMI (ß-blocker: 129.5±29.7 g/m2, no ß-blocker: 117.4±27.4 g/m2; p=0.02) compared with patients who were not treated with ß-blockers.Conclusions: In our cohort, ß-blocker use was associated with high central but not brachial PP and with high central AIx and high LVMI. Non-invasive measurement of central hemodynamic parameters may improve the evaluation of antihypertensive treatment efficacy in patients with type 2 diabetes.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-66160 (URN)
    Available from: 2011-03-04 Created: 2011-03-04 Last updated: 2017-03-27Bibliographically approved
    4. Central pulse pressure elevation is common in patients with type 2 diabetes and office normotension, and is associated with markers of atherosclerosis
    Open this publication in new window or tab >>Central pulse pressure elevation is common in patients with type 2 diabetes and office normotension, and is associated with markers of atherosclerosis
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    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The aim of this study was to describe the prevalence of elevated central pulsepressure (CPP) in patients with type 2 diabetes and office normotension, and to investigatewhether elevated CPP was associated with markers of atherosclerosis in these patients. Wedetermined office and central blood pressure, carotid intima-media thickness (IMT) and aorticpulse wave velocity (PWV) in 167 patients with type 2 diabetes and office normotension(<130/80 mmHg). Patients with office normotension and CPP ≥50 mmHg (n=32) hadsignificantly higher carotid IMT (0.76±0.2 mm vs 0.71±0.1 mm, p=0.041) and aortic PWV(11.0±2.5 m/s vs 9.5±1.8 m/s, p<0.01) than patients with office normotension and CPP <50mmHg (n=135). We conclude that almost one in five patients with type 2 diabetes and officenormotension had elevated CPP, and that this was associated with markers of both structuraland functional atherosclerosis.

    Keyword
    Type 2 diabetes, central pulse pressure, hypertension, pulse wave velocity
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-76136 (URN)
    Available from: 2012-03-28 Created: 2012-03-28 Last updated: 2017-03-27Bibliographically approved
    5. Ambulatory systolic blood pressure predicts left ventricular mass in type 2 diabetes, independently of central systolic blood pressure
    Open this publication in new window or tab >>Ambulatory systolic blood pressure predicts left ventricular mass in type 2 diabetes, independently of central systolic blood pressure
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    2012 (English)In: Blood Pressure Monitoring, ISSN 1359-5237, E-ISSN 1473-5725, Vol. 17, no 4, 139-144 p.Article in journal (Refereed) Published
    Abstract [en]

    Objectives: Both ambulatory and central blood pressures have been reported to correlate more closely than office blood pressure with left ventricular mass index (LVMI). The aim of this study was to test whether ambulatory systolic blood pressure (SBP) predicts LVMI independently of central SBP in patients with type 2 diabetes.

    Methods: We determined office, ambulatory and central blood pressures and performed echocardiography in 460 patients with type 2 diabetes, who participated in the CARDIPP (Cardiovascular Risk factors in Patients with Diabetes – a Prospective study in Primary care) study (ClinicalTrials.gov number NCT 01049737).

    Results: In separate multivariable regression models, both 24-hour ambulatory SBP, ambulatory day-time SBP, and ambulatory night-time SBP were significantly associated with LVMI, independently of central SBP, age, sex, BMI, ambulatory 24-hour heart rate, duration of known diabetes and presence or absence of any antihypertensive medications (r = 0.19, 0.17 and 0.18, respectively, P <0.01). All ambulatory SBP parameters, but not central SBP, were significantly associated with LVMI independently of office SBP.

    Conclusions: Ambulatory SBP predicted LVMI independently of central SBP in patients with type 2 diabetes. The use of ambulatory blood pressure measurements may be encouraged as a tool for refined risk stratification of patients with type 2 diabetes.

    Place, publisher, year, edition, pages
    Lippincott Williams & Wilkins, 2012
    Keyword
    ambulatory blood pressure, central blood pressure, hypertension, left ventricular hypertrophy, target organ damage, type 2 diabetes
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-76137 (URN)10.1097/MBP.0b013e328355fdfb (DOI)000306330300001 ()
    Available from: 2012-03-28 Created: 2012-03-28 Last updated: 2017-03-27Bibliographically approved
  • 36.
    Steinvall, Ingrid
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Bak, Zoltan
    Linköping University, Department of Medicine and Health Sciences, Anesthesiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Surgery UHL.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Unit . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Acute kidney injury is common, parallels organ dysfunction or failure, and carries appreciable mortality in patients with major burns: a prospective exploratory cohort study2008In: Critical Care, ISSN 1364-8535, Vol. 12, no R124Article in journal (Refereed)
    Abstract [en]

    Introduction: The purpose of this study was to determine the incidence, time course, and outcome of acute kidney injury after major burns and to evaluate the impact of possible predisposing factors ( age, gender, and depth and extent of injury) and the relation to other dysfunctioning organs and sepsis.

    Method: We performed an explorative cohort study on patients with a TBSA% (percentage burned of total body surface area) of 20% or more who were admitted to a national burn centre. Acute kidney injury was classified according to the international consensus classification of RIFLE ( Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease). Prospectively collected clinical and laboratory data were used for assessing organ dysfunction, systemic inflammatory response, and sepsis.

    Results: The incidence of acute kidney injury among major burns was 0.11 per 100,000 people per year. Of 127 patients, 31 (24%) developed acute kidney injury (12% Risk, 8% Injury, and 5% Failure). Mean age was 40.6 years (95% confidence interval [CI] 36.7 to 44.5), TBSA% was 38.6% (95% CI 35.5% to 41.6%), and 25% were women. Mortality was 14% and increased with increasing RIFLE class (7% normal, 13% Risk, 40% Injury, and 83% Failure). Renal dysfunction occurred within 7 days in 55% of the patients and recovered among all survivors. Age, TBSA%, and extent of full thickness burns were higher among the patients who developed acute kidney injury. Pulmonary dysfunction and systemic inflammatory response syndrome were present in all of the patients with acute kidney injury and developed before the acute kidney injury. Sepsis was a possible aggravating factor in acute kidney injury in 48%. Extensive deep burns (25% or more full thickness burn) increased the risk for developing acute kidney injury early (risk ratio 2.25).

    Conclusions: Acute kidney injury is common, develops soon after the burn, and parallels other dysfunctioning organs. Although acute kidney injury recovered in all survivors, in higher acute kidney injury groups, together with cardiovascular dysfunction, it correlated with mortality.

  • 37.
    Huang-Link, Yu-Min
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology.
    Al-Hawasi, Abbas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Ophthalmology in Linköping.
    Lindehammar, Hans
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Clinical Neurophysiology.
    Acute optic neuritis: retinal ganglion cell loss precedes retinal nerve fiber thinning.2015In: Neurological Sciences, ISSN 1590-1874, E-ISSN 1590-3478, Vol. 36, no 4, 617-620 p.Article in journal (Refereed)
    Abstract [en]

    Optic neuritis (ON) causes axonal loss as reflected by thinning of retinal nerve fiber layer (RNFL) and can be tracked by optical coherence tomography (OCT) about 6 months after ON onset, when swelling of optic nerve head (ONH) has vanished. Changes of macular ganglion cell layer (GCL) thickness provide another window to track the disease process in ON. GCL thinning over time in relation to RNFL change after ON remains elusive. Using OCT, we followed 4 patients with acute unilateral isolated ON for more than 9 months. A diagnosis of multiple sclerosis (MS) was established in all 4 patients. First follow-up was 2-3 weeks after ON onset, and thereafter every 2-3 months. RNFL swelling peaked during first month after acute ON, followed by rapidly reduced swelling (pseudoatrophy) during following 2 months, and thereafter successively vanished 6 months after ON onset. GCL thinning was observed 1-3 months after ON onset, i.e. already during optic disk swelling and before real RNFL thinning. The results imply that quantifying GCL thickness provides opportunities to monitor early axonal loss and ON-to-MS progression, and facilitates distinguishing real atrophy from pseudoatrophy of RNFL after acute ON.

  • 38.
    Valyukh, Sergiy
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Adaptive liquid crystal lenses for display applications2012In: SID-ME Spring Meeting 2012, 2012Conference paper (Other academic)
    Abstract [en]

    This work is devoted to study of adaptive liquid (LC) lens arrays utilized as a switcher between 2D and 3D autostereoscopic displays. In addition, the adaptive lens array can set and control viewing zones of an autostereoscopic display. The needed spatial distribution of LC director caused the lens effect can be achieved due to a non-uniform electric field or inhomogeneous alignment. In order to obtain a non-uniform electric field, it is necessary a pattered structure of electrodes or a specific design, e.g. non-uniform thickness of a dielectric layer sandwiched between the electrodes and LC. The inhomogeneous alignment is achieved due to a non-uniform distribution of the pre-tilt angle or anchoring energy. Analysis of adaptive LC lenses based on a non-uniform electric field and inhomogeneous alignment is done.

  • 39.
    Eita, Mohamed
    et al.
    Royal Institute Technology KTH.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Granberg, Hjalmar
    Innventia AB.
    Wagberg, Lars
    Royal Institute Technology KTH.
    Addition of silica nanoparticles to tailor the mechanical properties of nanofibrillated cellulose thin films2011In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 363, no 2, 566-572 p.Article in journal (Refereed)
    Abstract [en]

    Over the last decade, the use of nanocellulose in advanced technological applications has been promoted both due the excellent properties of this material in combination with its renewability. In this study, multilayered thin films composed of nanofibrillated cellulose (NFC), polyvinyl amine (PVAm) and silica nanoparticles were fabricated on polydimethylsiloxane (PDMS) using a layer-by-layer adsorption technique. The multilayer build-up was followed in situ by quartz crystal microbalance with dissipation, which indicated that the PVAm-SiO(2)-PVAm-NFC system adsorbs twice as much wet mass material compared to the PVAm-NFC system for the same number of bilayers. This is accompanied with a higher viscoelasticity for the PVAm-SiO(2)-PVAm-NFC system. Ellipsometry indicated a dry-state thickness of 2.2 and 3.4 nm per bilayer for the PVAm-NFC system and the PVAm-SiO(2)-PVAm-NFC system, respectively. Atomic force microscopy height images indicate that in both systems, a porous network structure is achieved. Youngs modulus of these thin films was determined by the Strain-Induced Elastic Buckling Instability for Mechanical Measurements (SIEBIMM) technique. The Youngs modulus of the PVAm/NFC films was doubled, from 1 to 2 GPa, upon incorporation of silica nanoparticles in the films. The introduction of the silica nanoparticles lowered the refractive index of the films, most probably due to an increased porosity of the films.

  • 40.
    Sani, Negar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Addressability and GHz Operation in Flexible Electronics2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The discovery of conductive polymers in 1977 opened up a whole new path for flexible electronics. Conducting polymers and organic semiconductors are carbon rich compounds that are able to conduct charges while flexed and are compatible with low-cost and large-scale processes including printing and coating techniques. The conducting polymer has aided the rapidly expanding field of flexible electronics, leading to many new applications such as electronic skin, RFID tags, smart labels, flexible displays, implantable medical devices, and flexible sensors.

    However, there are several remaining challenges in the production and implementation of flexible electronic materials and devices. The  conductivity of organic conductors and semiconductors is still orders of magnitude lower compared to their inorganic counterparts. In addition, non-flexible inorganic semiconductors still remain the materials of choice for high frequency applications; since the charge carrier mobility and thus operational speed of the organic materials are limited. Therefore, there remains a high demand to combine the high frequency operation of inorganic semiconductors with the flexible fabrication methods of organic systems for future electronics.

    In addition to the challenges in the choice of materials in flexible electronics, the upscaling of the flexible devices and implementing them in circuits can also be complicated. Lack of non-linearity is an issue that arises when flexible devices with linear behavior need to be incorporated in an array or matrix form. Non-linearity is important for applications such as displays and memory arrays, where the devices are arranged as matrix cells addressed by their row and column number. If the behavior of cells in the matrix is linear, addressing each cell affects the adjacent cells. Therefore, inducing non-linearity and, consequently, addressability in such linear devices is the first step before scaling up into matrix schemes.

    In this work, non-linear organic/inorganic hybrid devices are produced to overcome the limitations mentioned above and leverage the advantages of both organic and inorganic materials. Two novel methods are developed to incorporate non-flexible inorganic semiconductors into ultra-high frequency (UHF) flexible devices. In the first method, Si is ground into a powder with micrometer-sized particles and printed through standard screen printing. For the first time, allprinted flexible diodes operating in the GHz range are produced. The energy harvesting application of the printed diodes is demonstrated in a flexible circuit coupling an antenna and the display to the diode.

    A second and simpler room-temperature method based on lamination was later developed, which further improves device performance and operational frequency. For the first time, a flexible semiconducting composite film consisting of Si micro-particles, glycerol, and nano-fibrillated cellulose is produced and used as the semiconducting layer of the UHF diode.

    The diodes fabricated through both mentioned processes are demonstrated in energy harvesting applications in the GHz range; however, they can also serve as rectifiers or non-linear elements in any other flexible and UHF circuit.

    Furthermore, a new approach is developed to induce non-linearity and hence addressability in linear devices in order to make their implementation in flexible matrix form feasible. This is accomplished by depositing a ferroelectric layer on a device electrode and thus controlling charge transfer through the electrode. The electrode current becomes limited to the charge displacement current established in the ferroelectric layer during polarization. Thus, the current does not follow the voltage linearly and non-linearity is induced in the device. The polarization voltage is dictated by the thickness of the ferroelectric layer. Therefore, the switching voltage of the device can be tuned by adjusting the ferroelectric layer thickness. In this work, the organic ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) is used due to its distinctive properties such as stability, high polarizability and simple processability. The polarization of P(VDF-TrFE) through an electrolyte and an electrophoretic liquid is investigated. In addition, a simple model is presented in order to understand the field and potential distribution, and the ferroelectric polarization, in the P(VDF-TrFE)-electrolyte contact. The induction of non-linearity through P(VDF-TrFE) is successfully demonstrated in novel addressable and bistable devices and memory elements such as non-linear electrophoretic display cells, organic ferroelectrochromic displays (FeOECDs), and ferroelectrochemical organic transistors (FeOECTs).

    List of papers
    1. All-printed diode operating at 1.6 GHz
    Open this publication in new window or tab >>All-printed diode operating at 1.6 GHz
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    2014 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 111, no 33, 11943-11948 p.Article in journal (Refereed) Published
    Abstract [en]

    Printed electronics are considered for wireless electronic tags and sensors within the future Internet-of-things (IoT) concept. As a consequence of the low charge carrier mobility of present printable organic and inorganic semiconductors, the operational frequency of printed rectifiers is not high enough to enable direct communication and powering between mobile phones and printed e-tags. Here, we report an all-printed diode operating up to 1.6 GHz. The device, based on two stacked layers of Si and NbSi2 particles, is manufactured on a flexible substrate at low temperature and in ambient atmosphere. The high charge carrier mobility of the Si microparticles allows device operation to occur in the charge injection-limited regime. The asymmetry of the oxide layers in the resulting device stack leads to rectification of tunneling current. Printed diodes were combined with antennas and electrochromic displays to form an all-printed e-tag. The harvested signal from a Global System for Mobile Communications mobile phone was used to update the display. Our findings demonstrate a new communication pathway for printed electronics within IoT applications.

    Place, publisher, year, edition, pages
    National Academy of Sciences, 2014
    Keyword
    UHF; silicon particle
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-110476 (URN)10.1073/pnas.1401676111 (DOI)000340438800027 ()25002504 (PubMedID)
    Note

    Funding Agencies|Knut and Alice Wallenberg Foundation (Power Paper Project) [KAW 2011.0050]; Onnesjo Foundation; Swedish Research Council Linnaeus Grant LiLi-NFM; European Regional Development Fund through Tillvaxtverket (Project PEA-PPP)

    Available from: 2014-09-15 Created: 2014-09-12 Last updated: 2017-02-03Bibliographically approved
    2. Polarization of ferroelectric films through electrolyte
    Open this publication in new window or tab >>Polarization of ferroelectric films through electrolyte
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    2016 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 28, no 10, 105901Article in journal (Refereed) Published
    Abstract [en]

    A simplified model is developed to understand the field and potential distribution through devices based on a ferroelectric film in direct contact with an electrolyte. Devices based on the ferroelectric polymer polyvinylidenefluoride-trifluoroethylene (PVDF-TrFE) were produced – in metalferroelectric-metal, metal-ferroelectric-dielectric-metal, and metal-ferroelectric-electrolyte-metal architectures – and used to test the model, and simulations based on the model and these fabricated devices were performed. From these simulations we find indication of progressive polarization of the films. Furthermore, the model implies that there is a relation between the separation of charge within the devices and the observed open circuit voltage. This relation is confirmed experimentally. The ability to polarize ferroelectric polymer films through aqueous electrolytes, combined with the strong correlation between the properties of the electrolyte double layer and the device potential, opens the door to a variety of new applications for ferroelectric technologies, e.g., regulation of cell culture growth and release, steering molecular self-assembly, or other large area applications requiring aqueous environments.

    Place, publisher, year, edition, pages
    Institute of Physics (IOP), 2016
    National Category
    Physical Sciences Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-121802 (URN)10.1088/0953-8984/28/10/105901 (DOI)000371007800015 ()
    Note

    Funding agencies:  Swedish Governmental Agency for Innovation Systems (VINNOVA) [2010-00507]; Knut and Alice Wallenberg Foundation; Advanced Functional Materials Center at Linkoping University; Onnesjo Foundation

    Available from: 2015-10-07 Created: 2015-10-07 Last updated: 2017-02-03Bibliographically approved
  • 41.
    Persson, P.
    et al.
    Uppsala University, Sweden.
    Friederich-Persson, M.
    Uppsala University, Sweden.
    Fasching, A.
    Uppsala University, Sweden.
    Hansell, P.
    Uppsala University, Sweden.
    Inagi, R.
    University of Tokyo, Japan.
    Palm, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Uppsala University, Sweden.
    Adenosine A(2)a receptor stimulation prevents proteinuria in diabetic rats by promoting an anti-inflammatory phenotype without affecting oxidative stress2015In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 214, no 3, 311-318 p.Article in journal (Refereed)
    Abstract [en]

    AimDiabetic patients are at increased risk for kidney disease. There is presently no clinical treatment available that effectively protects kidney function in diabetics. This study investigates whether chronic stimulation of the adenosine A(2a) receptor (A(2a)AR) protects kidney function in insulinopenic diabetic rats. MethodsStreptozotocin-induced diabetic rats and corresponding controls were chronically treated with the adenosine A(2a)AR agonist CGS21680 throughout the four-week diabetes duration. Kidney function was thereafter investigated, and urine and plasma samples were collected for analysis of protein, oxidative stress and inflammatory markers. ResultsGlomerular filtration rate, renal blood flow, filtration fraction and diabetes-induced kidney hypoxia were all unaffected by chronic A(2a)AR stimulation. Furthermore, diabetic rats had increased oxidative stress, which was further increased by chronic A(2a)AR stimulation. However, the 10-fold increased urinary protein excretion observed in the diabetic rats was completely prevented by chronic A(2a)AR stimulation. These beneficial effects were accompanied by reduced levels of the pro-inflammatory TNF- and increased levels of the anti-inflammatory IL-10 as well as decreased infiltration of macrophages, glomerular damage and basement membrane thickness. ConclusionChronic A(2a)AR stimulation prevents proteinuria and glomerular damage in experimental diabetes via an anti-inflammatory mechanism independent of oxidative stress and kidney hypoxia.

  • 42.
    Karlsson, L M
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Adsorption of human serum albumin in porous silicon gradients2003Conference paper (Other academic)
    Abstract [en]

    Backside etching has been utilized to produce gradients of pore size and layer thickness in porous silicon. Human serum albumin (HSA) was adsorbed on such gradients at two different pH values: 4.9, the pI of HSA, and 7.4, the physiological pH. The samples were investigated by scanning electron microscopy, spectroscopic ellipsometry, and autoradiography. The results show that the protein adsorbed displays a gradient along with the pore size and the thickness gradient. The higher than current density used during etching, the more sway-back shaped curves were seen for the protein adsorption pattern, independent of pH. When 50 mA/cm2 current density was used during etching, the quota between the maximal intensity value and the plateau value seen after adsorption of the HSA increased for pH 7.4.

  • 43.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Adsorption of Proteins at Solid Surfaces2014In: Ellipsometry of Functional Surfaces and Films / [ed] Hinrichs, Karsten; Eichhorn Klaus-Jochen, Springer Berlin/Heidelberg, 2014, 29-46 p.Chapter in book (Refereed)
    Abstract [en]

    Ellipsometry has a very high thin film sensitivity and can resolve sub-nm changes in the thickness of a protein film on a solid substrates. Being a technique based on photons in and photons out it can also be applied at solid-liquid interfaces. Ellipsometry has therefore found many in situ applications on protein layer dynamics but studies of protein layer structure are also frequent. Numerous ex situ applications on detection and quantification of protein layers are found and several biosensing concepts have been proposed. In this chapter, the use of ellipsometry in the above mentioned areas is reviewed and experimental methodology including cell design is briefly discussed. The classical ellipsometric challenge to determine both thickness and refractive index of a thin film is addressed and an overview of strategies to determine surface mass density is given. Included is also a discussion about spectral representations of optical properties of a protein layer in terms of a model dielectric function concept and its use for analysis of protein layer structure.

  • 44.
    Åstrand, Håkan
    et al.
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences.
    Rydén-Ahlgren, Åsa
    Department of Clinical Physiology, University Hospital Malmö, University of Lund.
    Sandgren, Thomas
    Department of Surgery, Helsingborg Hospital.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences.
    Age-related increase in wall stress of the human abdominal aorta: An in vivo study2005In: Journal of Vascular Surgery, ISSN 0741-5214, Vol. 42, no 5, 926-931 p.Article in journal (Refereed)
    Abstract [en]

    Background

    The regulation of wall stress in the abdominal aorta (AA) of humans might be of specific interest, because the AA is the most common site for aneurysm formation in which wall stress seems to be an important pathophysiological factor. We studied the age-related changes in wall stress of the AA in healthy subjects, with the common carotid artery (CCA) as a comparison.

    Methods

    A total of 111 healthy subjects were examined with B-mode ultrasonography to determine the lumen diameter and intima-media thickness (IMT) in the AA and the CCA.

    Results

    Aortic IMT was affected by age in men and by both age and lumen diameter in women. Carotid IMT was affected by age and pulse pressure in both men and women. Wall stress was higher in the AA than in the CCA (P < .001), and men had higher wall stress than women in both the AA (P < .001) and the CCA (P < .05). Furthermore, wall stress was constant during life in the CCA of men and women and in the AA of women. In the male aorta, however, wall stress increased with age (P < 0.01).

    Conclusions

    Arterial diameters increase with age, and a compensatory thickening of the arterial wall prevents the circumferential wall stress from increasing. However, this compensatory response is insufficient in the male AA and results in an increase in stress with age. These findings might explain the propensity for aneurysms to develop in the AA of men.

  • 45.
    Germundsson, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Karanis, Georgios
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Fagerholm, Per
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Ophthalmology in Linköping.
    Lagali, Neil
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Ophthalmology in Linköping.
    Age-Related Thinning of Bowman's Layer in the Human Cornea In Vivo2013In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, Vol. 54, no 9, 6143-6149 p.Article in journal (Refereed)
    Abstract [en]

    Purpose. To determine the thickness of Bowman's layer (BL) in vivo in a healthy population and to determine its variation with age.

    Methods. Eighty-two subjects aged 15 to 88 years with clear, healthy corneas were examined bilaterally with laser scanning in vivo confocal microscopy (IVCM). Bowman's layer thickness was determined from IVCM images of anterior and posterior BL boundaries. For a given eye, BL thickness was averaged across four central locations by two independent observers. In addition, central corneal thickness was measured by time-domain optical coherence tomography.

    Results. A significant negative correlation of BL thickness with age was found in right eyes (Pearson r = −0.579, P < 0.0001) and in left eyes (r = −0.558, P < 0.0001). Linear regression analysis yielded a decline in BL thickness of 0.06 μm per year. In 41 older subjects (mean age, 64.4 years), BL thickness was significantly thinner (mean ± SD, 8.6 ± 1.7 μm in right eyes) than that in 41 younger subjects (mean age, 31.6 years) (mean ± SD, 10.7 ± 1.6 μm in right eyes) (P < 0.001). No correlation of corneal thickness with age or of BL thickness with corneal thickness was observed. Strong intereye correlations in BL thickness (r = 0.771, P < 0.0001) and corneal thickness (r = 0.969, P < 0.001) were found.

    Conclusions. Bowman's layer thins with age in the normal cornea, losing one-third of its thickness between the ages of 20 and 80 years. In vivo measurement of BL thickness by IVCM could aid in clinical assessment and planned treatments of the anterior cornea.

  • 46.
    Wikner, Jacob
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Zötterman, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Jalili, Armin
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Aiming for the cloud - a study of implanted battery-free temperature sensors using NFC2016In: 2016 INTERNATIONAL SYMPOSIUM ON INTEGRATED CIRCUITS (ISIC), IEEE , 2016Conference paper (Refereed)
    Abstract [en]

    In this paper we present results based on measurements of implantable devices which can be powered externally and communicated with using the near-field communication (NFC) infrastructure. NFC allows us to not have a dedicated gateway and intra-body communication to bridge the data from sensors to phone. In our trials, we have used commercially available sub-components and mounted them on a thin plastic with printed interconnections and coated them for bio-compatibility. Devices were implanted in porcine models during one week. We could during this time measure the in-vivo body temperature through skin and subcutaneous tissue ranging in thickness from some mm to a couple of cm. The implanted sensor devices are mounted on thin, printed-electronics plastic sheets where the coils and conductors are designed with different types of materials. The choice of materials is done in order to offer a low-cost solution to read out data from in-vivo sensors. We compile measured data, practical results and guidelines, together with theoretical results referring to the design of the implanted inductive NFC coil as well as the energy transfer from one mobile device to another.

  • 47.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lundskog, Anders
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ivanov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kakanakova-Georgieva, Anelia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Forsberg, Urban
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    AlGaN Multiple Quantum Wells and AlN Grown in a Hot-wall MOCVD for Deep UV Applications2009In: ECS Transactions, Vol. 25, Iss. 8, ECS , 2009, 837-844 p.Conference paper (Refereed)
    Abstract [en]

    AlxGa1-xN multiple quantum wells (MQW) were grown on AlN epilayer grown on 4H-SiC substrate. The growth was performed without interruption in a horizontal hot-wall MOCVD reactor using a mixture of hydrogen and nitrogen as carrier gases. The precursors were ammonia, trimethylaluminum and trimethylgallium. Results obtained from X-ray diffraction and infra-red reflectance were used to obtain the composition of the films when growing simple AlxGa1 xN layer. Visible reflectance was used to evaluate the thickness of the films. Finally the MQW parameters as thicknesses and composition variation were obtained by scanning transmission electron microscopy and demonstrated an agreement with the growth parameters used

  • 48.
    Yazdi, Gholamreza
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gogova, D
    Leibniz Institute Crystal Growth.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Aligned AlN nanowires by self-organized vapor-solid growth2009In: NANOTECHNOLOGY, ISSN 0957-4484, Vol. 20, no 49, 495304- p.Article in journal (Refereed)
    Abstract [en]

    Highly oriented AlN single crystal nanowires with aspect ratio up to 600, diameter in the range of 40-500 nm, and 100 mu m lengths, have been synthesized via a vapor-solid growth mechanism. The results were obtained at 1750 degrees C and 850 mbar nitrogen pressure on vicinal SiC substrates pretreated by SiC sublimation epitaxy in order to attain distinguishable terraces. It was found that the nanowires change in thickness after they have reached a critical length, and this fact contributes to an understanding of the growth mechanism of AlN nanowires. The nanowires are hexagonally shaped and perfectly aligned along the [0001] direction with a small tilt given by the substrate vicinality. Under nitrogen excess a preferential growth along the c-axis of the wurtzite structure takes place while below some critical value of nitrogen pressure the growth mode switches to lateral. The AlN nanowires are shown to have a dislocation free wurtzite crystal structure. Some possible applications are discussed.

  • 49.
    Johansson, Joakim
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Department of Anesthesia and Intensive Care, Östersund Hospital, Östersund, Sweden.
    Steinvall, Ingrid
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Herwald, Heiko
    Lund University, Sweden.
    Lindbom, Lennart
    Karolinska Institute, Sweden.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Alteration of Leukocyte Count Correlates With Increased Pulmonary Vascular Permeability and Decreased PaO2:FiO(2) Ratio Early After Major Burns2015In: Journal of Burn Care & Research, ISSN 1559-047X, E-ISSN 1559-0488, Vol. 36, no 4, 484-492 p.Article in journal (Refereed)
    Abstract [en]

    Leukocytes are activated systemically and their numbers increase soon after a burn followed by a rapid decline to low normal or subnormal levels, possibly by increased extravasation. Experimental data support that an important target for such extravasation is the lungs and that leukocytes when they adhere to endothelial cells cause an increase in vascular permeability. The authors investigated a possible relation between early increased pulmonary vascular permeability or a decreased PaO2:FiO(2) ratio and the dynamic change in concentration of blood leukocytes after a burn. This is a prospective, exploratory, single-center study. The authors measured the dynamic changes of leukocytes in blood starting early after the burn, pulmonary vascular permeability index by thermodilution, and PaO2:FiO(2)-ratios in 20 patients during the first 21 days after a major burn (greater than20% TBSA%). Median TBSA was 40% interquartile range (IQR, 25-52) and full thickness burn 28% (IQR, 2-39). There was a correlation between the early (less than24 hours) alteration in white blood cell count and both early increased pulmonary vascular permeability (r = .63, P = .004) and the decreased oxygenation index defined as PaO2:FiO(2) less than 27 kPa (P = .004). The authors have documented a correlation between dynamic change of blood leukocytes and pulmonary failure early after burns.

  • 50.
    Wallin, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics . Linköping University, The Institute of Technology.
    Alumina Thin Film Growth: Experiments and Modeling2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work presented in this thesis deals with experimental and theoretical studies related to the growth of crystalline alumina thin films. Alumina, Al2O3, is a polymorphic material utilized in a variety of applications, e.g., in the form of thin films. Many of the possibilities of alumina, and the problems associated with thin film synthesis of the material, are due to the existence of a range of different crystalline phases. Controlling the formation of the desired phase and the transformations between the polymorphs is often difficult.

    In the experimental part of this work, it was shown that the thermodynamically stable alpha phase, which normally is synthesized at substrate temperatures of around 1000 °C, can be grown using reactive sputtering at a substrate temperature of 500 °C by controlling the nucleation surface. This was done by predepositing a Cr2O3 nucleation layer. Moreover, it was found that an additional requirement for the formation of the α phase is that the depositions are carried out at low enough total pressure and high enough oxygen partial pressure. Based on these observations, it was concluded that energetic bombardment, plausibly originating from energetic oxygen, is necessary for the formation of α alumina (in addition to the effect of the chromia nucleation layer). Further, the effects of impurities, especially residual water, on the growth of crystalline films were investigated by varying the partial pressure of water in the ultra high vacuum (UHV) chamber. Films deposited onto chromia nucleation layers exhibited a columnar structure and consisted of crystalline α-alumina if deposited under UHV conditions. However, as water to a partial pressure of 1x10-5 Torr was introduced, the columnar growth was interrupted. Instead, a microstructure consisting of small, equiaxed grains was formed, and the gamma-alumina content was found to increase with increasing film thickness. When gamma-alumina was formed under UHV conditions, no effects of residual water on the phase formation was observed. Moreover, the H content was found to be low (< 1 at. %) in all films. Consequently, this shows that effects of residual gases during sputter deposition of oxides can be considerable, also in cases where the impurity incorporation in the films is found to be low.

    In the modeling part of the thesis, density functional theory based computational studies of adsorption of Al, O, AlO, and O2 on different alpha-alumina (0001) surfaces have been performed. The results give possible reasons for the difficulties in growing the α phase at low temperatures through the identification of several metastable adsorption sites, and also provide insights related to the effects of hydrogen on alumina growth.

    List of papers
    1. Phase control of Al2O3 thin films grown at low temperatures
    Open this publication in new window or tab >>Phase control of Al2O3 thin films grown at low temperatures
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    2006 (English)In: Thin Solid Films, ISSN 0040-6090, Vol. 513, no 1-2, 57-59 p.Article in journal (Refereed) Published
    Abstract [en]

    Low-temperature growth (500 °C) of α-Al2O3 thin films by reactive magnetron sputtering was achieved for the first time. The films were grown onto Cr2O3 nucleation layers and the effects of the total and O2 partial pressures were investigated. At 0.33 Pa total pressure and ≥ 16 mPa O2 partial pressure α-Al2O3 films formed, while at lower O2 pressure or higher total pressure (0.67 Pa), only γ phase was detected in the films (which were all stoichiometric). Based on these results we suggest that α phase formation was promoted by a high energetic bombardment of the growth surface. This implies that the phase content of Al2O3 films can be controlled by controlling the energy of the depositing species. The effect of residual H2O (10− 4 Pa) on the films was also studied, showing no change in phase content and no incorporated H (< 0.1%). Overall, these results are of fundamental importance in the further development of low-temperature Al2O3 growth processes.

    Place, publisher, year, edition, pages
    Elsevier, 2006
    Keyword
    Aluminum oxide, Chromium oxide, Sputtering, Ion bombardment, X-ray diffraction
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-14318 (URN)10.1016/j.tsf.2006.01.016 (DOI)
    Note
    Original publication: Andersson, J.M., Wallin, E., Helmersson, U., Kreissig, U. and Münger, E.P., Phase control of Al2O3 thin films grown at low temperatures, 2006, Thin Solid Films, (513), 1-2, 57-59. http://dx.doi.org/10.1016/j.tsf.2006.01.016. Copyright: Elsevier B.V., http://www.elsevier.com/ Available from: 2007-03-02 Created: 2007-03-02 Last updated: 2013-10-30Bibliographically approved
    2. Ab initio studies of Al, O, and O2 adsorption on α-Al2O3 (0001) surfaces
    Open this publication in new window or tab >>Ab initio studies of Al, O, and O2 adsorption on α-Al2O3 (0001) surfaces
    Show others...
    2006 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 74, no 12, 125409-1-125409-9 p.Article in journal (Refereed) Published
    Abstract [en]

    The interactions of Al, O, and O2 with different α- Al2O3 (0001) surfaces have been studied using ab initio density functional theory methods. All three surface terminations obtainable by cleaving the bulk structure [single Al-layer (AlO), double Al-layer (AlAl), and O terminations] have been considered, as well as a completely hydrogenated O-terminated surface. Adsorbed Al shows strong ioniclike interaction with the AlO - and O-terminated surfaces, and several metastable adsorption sites are identified on the O-terminated surface. On the completely hydrogenated surface, however, Al adsorption in the bulk position is found to be unstable or very weak for the studied configurations of surface H atoms. Atomic O is found to interact strongly with the AlAl -terminated surface, where also O2 dissociative adsorption without any appreciable barrier is observed. In contrast, O adsorption on the AlO -terminated surface is metastable relative to molecular O2. On the O-terminated surface, we find the creation of O surface vacancies to be plausible, especially upon exposure to atomic O at elevated temperatures. The results are mainly discussed in the context of alumina thin film growth and provide insight into phenomena related to, e.g., preferred adsorption sites and effects of hydrogen on the growth.

    Place, publisher, year, edition, pages
    College Park, MD, United States: American Physical Society, 2006
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-10427 (URN)10.1103/PhysRevB.74.125409 (DOI)000240872500080 ()
    Note

    Original publication: E. Wallin, J.M. Andersson, E.P. Münger, V. Chirita & U. Helmersson, Ab initio studies of Al, O, and O2 adsorption on α- Al2 O3 (0001) surfaces, 2006, Physical Review B, (74), 125409. http://dx.doi.org/10.1103/PhysRevB.74.125409. Copyright: The America Physical Society, http://prb.aps.org/

    Available from: 2007-12-12 Created: 2007-12-12 Last updated: 2014-06-18Bibliographically approved
    3. Influence of residual water on magnetron sputter deposited crystalline Al2O3 thin films
    Open this publication in new window or tab >>Influence of residual water on magnetron sputter deposited crystalline Al2O3 thin films
    2008 (English)In: Thin Solid Films, ISSN 0040-6090, Vol. 516, no 12, 3877-3883 p.Article in journal (Refereed) Published
    Abstract [en]

    The effects of residual water on the phase formation, composition, and microstructure evolution of magnetron sputter deposited crystalline alumina thin films have been investigated. To mimic different vacuum conditions, depositions have been carried out with varying partial pressures of H2O. Films have been grown both with and without chromia nucleation layers. It is shown that films deposited onto chromia nucleation layers at relatively low temperatures (500 °C) consists of crystalline alpha-alumina if deposited at a low enough total pressure under ultra high vacuum (UHV) conditions. However, as water was introduced a gradual increase of the gamma phase content in the film with increasing film thickness was observed. At the same time, the microstructure changed drastically from a dense columnar structure to a structure with small, equiaxed grains. Based on mass spectrometry measurements and previous ab initio calculations, we suggest that either bombardment of energetic negative (or later neutralized) species being accelerated over the target sheath voltage, adsorbed hydrogen on growth surfaces, or a combination of these effects, is responsible for the change in structure. For films containing the metastable gamma phase under UHV conditions, no influence of residual water on the phase content was observed. The amounts of hydrogen incorporated into the films, as determined by elastic recoil detection analysis, were shown to be low. Overall, the results demonstrate that residual water present during film growth drastically affects film properties, also in cases where the hydrogen incorporation is found to be low.

    Place, publisher, year, edition, pages
    ScienceDirect, 2008
    Keyword
    Aluminum oxide, Phase formation, Sputtering, Water
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-11476 (URN)10.1016/j.tsf.2007.07.135 (DOI)
    Note
    Original publication: E. Wallin, J.M. Andersson, M. Lattemann, and U. Helmersson, Influence of residual water on magnetron sputter deposited crystalline Al2O3 thin films, 2008, Thin Solid Films, (516), 12, 3877-3883. http://dx.doi.org/10.1016/j.tsf.2007.07.135. Copyright: Elsevier B.V., http://www.elsevier.com/Available from: 2008-04-03 Created: 2008-04-03 Last updated: 2013-10-30Bibliographically approved
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