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  • 1.
    Rastgoo Lahrood, Atena
    et al.
    Technical University of Munich, Germany; Nanosyst Initiat Munich, Germany; Centre NanoScience, Germany.
    Björk, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Chemistry. Linköping University, Faculty of Science & Engineering.
    Heckl, Wolfgang M.
    Technical University of Munich, Germany; Nanosyst Initiat Munich, Germany; Centre NanoScience, Germany; Deutsch Museum, Germany.
    Lackinger, Markus
    Technical University of Munich, Germany; Nanosyst Initiat Munich, Germany; Centre NanoScience, Germany; Deutsch Museum, Germany.
    1,3-Diiodobenzene on Cu(111) - an exceptional case of on-surface Ullmann coupling2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 68, 13301-13304 p.Article in journal (Refereed)
    Abstract [en]

    Ullmann coupling of 1,3-diiodobenzene is studied on Cu(111) surfaces in ultra-high vacuum (UHV). In situ Scanning Tunneling Microscopy (STM) at room temperature revealed an unexpected ordered arrangement of highly uniform reaction products adsorbed atop a closed iodine monolayer.

  • 2.
    Zhang, Xuanjun
    et al.
    Structure Research Laboratory and Department of Chemistry, University of Science and Technology of China.
    Xie, Yi
    Structure Research Laboratory and Department of Chemistry, University of Science and Technology of China.
    Zhao, Qingrui
    Structure Research Laboratory and Department of Chemistry, University of Science and Technology of China.
    Tian, Yupeng
    Department of Chemistry, Anhui University, China.
    1-D coordination polymer template approach to CdS and HgS aligned-nanowire bundles2003In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 27, no 5, 827-830 p.Article in journal (Refereed)
    Abstract [en]

    A 1D inorganic coordination polymer template route was firstly developed to synthesize metal sulfide aligned-nanowire bundles. Based on this strategy, CdS and HgS aligned-nanowire bundles with high yields were successfully prepared in a water system at room temperature using KCd(NCS)3 as a soft template. The results revealed that the morphologies of the MS (M=Cd, Hg) aligned-nanowire bundles were uniform with lengths of several microns and the diameters of each single wire were ca. 10–30 nm and 60–80 nm for CdS and HgS, respectively.

  • 3.
    Seppänen, Timo
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    248 nm cathodoluminescence in Al1-xInxN (0001) thin films grown on lattice-matched Ti1-yZryN (111) seed layers by low temperature magnetron sputter epitaxy2006In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 89, no 18Article in journal (Refereed)
    Abstract [en]

    Single-crystal Al0.8 In0.2 N (0001) thin films were grown epitaxially onto lattice-matched Ti0.2 Zr0.8 N (111) seed layers on MgO(111) substrates at 300 °C by magnetron sputter epitaxy. Low-energy ion-assisted epitaxial growth conditions were achieved by applying a substrate potential of -15 V. Cross-sectional high-resolution electron microscopy verified the epitaxy and high-resolution x-ray diffraction ω -rocking scans of the Al0.8 In0.2 N 0002 peak (full width at half maximum ∼2400 arc sec) indicated a high structural quality of the films. Cathodoluminescence measurements performed in a scanning electron microscope at 5 K revealed Al0.8 In0.2 N luminescence at 248 nm, or equivalently 5.0 eV, showing that Al0.8 In0.2 N is a promising material for deep-ultraviolet optoelectronic devices. © 2006 American Institute of Physics.

  • 4.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics.
    24th Anniversary World Congress on Biosensors – Biosensors 20142014Conference proceedings (editor) (Refereed)
    Abstract [en]

    Welcome to Biosensors 2014 and welcome to Melbourne, ranked as the world's most liveable city!

    This is the 24th anniversary edition of the World Congress on Biosensors and we continue to evolve, adapt and grow into new roles to serve the analytical needs of a rapidly changing society. Advances in telecommunications, expert systems and distributed diagnostics are prompting us to question the conventional ways we deliver healthcare, while robust industrial sensors are facilitating new paradigms in R&D and production. Personalisation of everything from medicine to environmental control, is giving new impetus to consumer choice and ownership of information, and will inevitably generate new payment structures and business models. Moreover, a deeper understanding of the bio/electronic interface leads us towards new horizons in areas such as bionics, power generation and computing.  Wearable, mobile and integrated sensors are becoming common place, but most current products have taken the easy path of incorporating physical sensors for parameters such as temperature, pressure, orientation or position. There is still a glaring absence of suitably robust and convenient commercial biosensors for body chemistries and ecosystems, and therein lies the real opportunities for progress.  We are a still-emerging technology that is fuelling scientific discovery and underpinning new products to enhance the length and quality of life.

    Always in a new country and always with fresh plenary speakers, we aim to reflect the latest and the best in Biosensors. This three-day event, organised by Elsevier in association with Biosensors & Bioelectronics, consists of two daily plenary presentations from leading figures in the field, followed by four parallel sessions, comprising a rigorously refereed selection of submitted papers. This year, we received 1,156 submissions of which 124 with be presented as regular Oral papers, with an additional 20 singled out as Invited talks and a further 12 selected for extended Keynote talks. The Keynote speakers have also been invited to submit full papers for consideration for the Biosensors and Bioelectronics Prize for the most original contribution to the Congress and the winners will be announced at the conference banquet on Thursday night. There will also be poster awards and you will find voting slips for each of the three days in your delegate bags. The winners of these awards and a prize draw, sponsored by Linköping University and Acreo Swedish ICT, will be announced at the closing ceremony on Friday. In order to enhance the valued medium of poster presentation, this year we have introduced a new Poster in my Pocket Ap.  Poster presenters have been able to upload a PDF of their poster prior to the conference to help increase the exposure of their work. This compliments the other new Ap introduced this year to place the full programme at your fingertips. Selected oral presentations will also have the opportunity to upload their talks online for future viewing.

    The academic programme, as usual, is enhanced by a fine collection of commercial exhibits and in addition to browsing their stands; you will be able to hear short elevator pitches during the breaks. We must thank our main commercial sponsor, Ercon for their generous and continued support of our congress. Thanks also to New Tools for Health for sponsoring the pre-congress Networking Event.  Now a regular feature for Biosensors, we have a pre-congress school, this year on Optical Biosensors, which is brought to you by Profs Fran Ligler and Tanya Monro. Last, but not least I must thank our marvellous Local Organising Committee chaired by Prof Justin Gooding, our hard working main Organising Committee, all the speakers and delegates, and the Elsevier team for all their support.

    Our delegates come from the four corners of the globe to hear the science, to grasp the opportunities and to meet the people; it’s going to be the best meeting yet. Enjoy and don’t forget to join us again in Gothenburg, Sweden, 24-27 May for Biosensor 2016!

  • 5. Brosselard, P.
    et al.
    Camara, N.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Jordà, X.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Montserrat, J.
    Millán, J.
    3.3 kV-10A 4H-SiC PiN diodes2009In: Materials Science Forum, Vols. 600-603, Trans Tech Publ. , 2009, 991-994 p.Conference paper (Refereed)
    Abstract [en]

    An innovative process has been developed by Linköping University to prepare the 4HSiC substrate surface before epitaxial growth. The processed PiN diodes have been characterized in forward and reverse mode at different temperature. The larger diodes (2.56 mm2) have a very low leakage current around 20 nA @ 500V for temperatures up to 300°C. A performant yield (68%) was obtained on these larger diodes have a breakdown voltage superior to 500V. Electroluminescence characteristics have been done on these devices and they show that there is no generation of Stacking Faults during the bipolar conduction.

  • 6.
    Lofgren, PM
    et al.
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    Hallin, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Gu, CY
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    Ji, W
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    3-d thermal and flow modeling of hot wall epitaxial chemical vapor deposition reactors, heated by induction2000In: Materials Science Forum, ISSN 0255-5476, Vol. 338-3, 153-156 p.Article in journal (Refereed)
    Abstract [en]

    A three dimensional computational model for temperature and flow predictions in hot wall chemical vapor deposition (CVD) reactors, heated by induction, is presented. It includes heating by a Radio Frequency (RF) coil, flow and heat transfer. Thermal radiation is modeled by a modified Monte Carlo method. Model predictions are compared to full scale experiments at Linkoping CVD reactor for epitaxial growth of silicon carbide (SIC). Both streamwise and spanwise temperature gradients are well predicted, with the temperature maximum location shifted slightly upstream compared to the measured. Additionally, the model succeeds in predicting a recirculation zone just downstream of the susceptor. It is demonstrated how thermal gradients can be greatly reduced by simple geometrical changes.

  • 7.
    Sundberg, Carina
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Al-Soud, Waleed A.
    University of Copenhagen, Denmark .
    Larsson, Madeleine
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Alm, Erik
    SMI, Sweden .
    Shakeri Yekta, Sepehr
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sorensen, Soren J.
    University of Copenhagen, Denmark .
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    454 pyrosequencing analyses of bacterial and archaeal richness in 21 full-scale biogas digesters2013In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 85, no 3, 612-626 p.Article in journal (Refereed)
    Abstract [en]

    The microbial community of 21 full-scale biogas reactors was examined using 454 pyrosequencing of 16S rRNA gene sequences. These reactors included seven (six mesophilic and one thermophilic) digesting sewage sludge (SS) and 14 (ten mesophilic and four thermophilic) codigesting (CD) various combinations of wastes from slaughterhouses, restaurants, households, etc. The pyrosequencing generated more than 160 000 sequences representing 11 phyla, 23 classes, and 95 genera of Bacteria and Archaea. The bacterial community was always both more abundant and more diverse than the archaeal community. At the phylum level, the foremost populations in the SS reactors included Actinobacteria, Proteobacteria, Chloroflexi, Spirochetes, and Euryarchaeota, while Firmicutes was the most prevalent in the CD reactors. The main bacterial class in all reactors was Clostridia. Acetoclastic methanogens were detected in the SS, but not in the CD reactors. Their absence suggests that methane formation from acetate takes place mainly via syntrophic acetate oxidation in the CD reactors. A principal component analysis of the communities at genus level revealed three clusters: SS reactors, mesophilic CD reactors (including one thermophilic CD and one SS), and thermophilic CD reactors. Thus, the microbial composition was mainly governed by the substrate differences and the process temperature.

  • 8.
    Wahab, Qamar Ul
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Kosugi, H
    Kyoto Univ, Dept Electron Sci & Engn, Kyoto, Japan Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden.
    Yano, H
    Kyoto Univ, Dept Electron Sci & Engn, Kyoto, Japan Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden.
    Hallin, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Kimoto, T
    Kyoto Univ, Dept Electron Sci & Engn, Kyoto, Japan Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden.
    Matsunami, H
    Kyoto Univ, Dept Electron Sci & Engn, Kyoto, Japan Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden.
    4H-and 6H-SiC MOSFETs fabricated on sloped sidewalls formed by molten KOH etching2002In: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, 1215-1218 p.Conference paper (Refereed)
    Abstract [en]

    Vertical 4H- and 6H-SiC MOSFETs have been fabricated on sloped sidewalls formed by molten KOH etching, which is expected to be free from the damage onto a channel region caused by a dry etching process. The slope angle could be controlled by adjusting etching temperature, and the anisotropy of inversion channel mobility was investigated. A higher inversion channel mobility and a lower threshold voltage were observed with increasing slope angle of channel region toward (1 (1) over bar 00) or (11 (2) over bar0). The highest mobility was 32 cm(2)/Vs for 6H-SiC, which is relatively high as an inversion channel mobility of UMOSFETs compared to previous works. The dependence of device performance on the slope angle and crystal orientation is discussed.

  • 9. Robert, T.
    et al.
    Marinova, M.
    Juillaguet, S.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Polychroniadis, E.K.
    Camassel, J.
    6H-type zigzag faults in low-doped 4H-SiC epitaxial layers.2010In: Mat. Sci. Forum, Vols. 645-648, 2010, 347-350 p.Conference paper (Refereed)
    Abstract [en]

    A new type of 6H zigzag faults has been identified from high resolution transmission electron microscopy (HRTEM) measurements performed on low-doped 4H-SiC homoepitaxial layer grown on off-axis substrates in a hot-wall CVD reactor. They are made of half unit cells of 6H with corresponding low temperature photoluminescence (LTPL) response ranging from about 3 eV to 2.5 eV at liquid helium temperature.

  • 10.
    Murugesan, Murali
    et al.
    Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Gothenburg, Sweden.
    Zanden, Carl
    Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Gothenburg, Sweden.
    Luo, Xin
    Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Gothenburg, Sweden; School of Mechatronics and Mechanical Engineering, Key Laboratory of New Displays and System Integration, Shanghai University, China .
    Ye, Lilei
    SHT Smart High-Tech AB, Gothenburg, Sweden.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liu, Johan
    Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Gothenburg, Sweden; School of Mechatronics and Mechanical Engineering, Key Laboratory of New Displays and System Integration, Shanghai University, China .
    A carbon fiber solder matrix composite for thermalmanagement of microelectronic devices2014In: Journal of Materials Chemistry C, ISSN 2050-7526, Vol. 2, no 35, 7184-7187 p.Article in journal (Refereed)
    Abstract [en]

    A carbon fiber based tin-silver-copper alloy matrix composite (CF-TIM) was developed via electrospinning of a mesophase pitch with polyimide and carbonization at 1000 °C, followed by sputter coating with titanium and gold, and alloy infiltration. The carbonized fibers, in film form, showed a thermal conductivity of ∼4 W m-1 K-1 and the CF-TIM showed an anisotropic thermal conductivity of 41 ± 2 W m-1 K-1 in-plane and 20 ± 3 W m-1 K-1 through-plane. The thermal contact resistance of the CF-TIM was estimated to be below 1 K mm2 W-1. The CF-TIM showed no reduction in effective through-plane thermal conductivity after 1000 temperature cycles, which indicates the potential use of CF-TIM in thermal management applications.

  • 11.
    Filla, Reno
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, The Institute of Technology.
    Olsson, Erik M. G.
    Dept. of Public Health and caring Sciences, Uppsala University, Sweden.
    Schéele, Bo H. C. von
    Stress Medicien AB, Bergvik, Sweden.
    Ohlsson, Kjell
    Linköping University, Department of Management and Engineering, Industrial ergonomics. Linköping University, The Institute of Technology.
    A Case Study on Quantifying the Workload of Working Machine Operators by Means of Psychophysiological MeasurementsManuscript (preprint) (Other academic)
    Abstract [en]

    In this study of eighteen wheel loader operators, test-driving a machine in three different traction force settings, we examine if a workload index derived from psychophysiological measurements of heart rate, finger temperature, skin conductance, respiration rate and end-tidal CO2-concentration in exhaled air can be used to assess operator workload in sufficient detail to use it as a complement to traditional subjective evaluations, and also to use such measurements in a workload-adaptive operator assistance system in a longer perspective.

  • 12.
    Li, Songjun
    et al.
    Central China Normal University.
    Ge, Yi
    Cranfield University, UK.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    A Catalytic and Positively Thermosensitive Molecularly Imprinted Polymer2011In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 21, no 6, 1194-1200 p.Article in journal (Refereed)
    Abstract [en]

    A catalytic and positively thermosensitive molecularly imprinted polymer is reported. This unique imprinted polymer was composed of 4-nitrophenyl phosphate-imprinted networks that exhibited a thermosensitive interpolymer interaction between poly(2-trifluoromethylacrylic acid) (PTFMA) and poly(1-vinylimidazole) (PVI), which contains catalytically active sites. At a relatively low temperature (such as 20 degrees C), this imprinted polymer did not demonstrate significant catalytic activity for the hydrolysis of 4-nitrophenyl acetate due to the interpolymer complexation between PVI and PTFMA, which blocked access to the active sites of PVI and caused shrinking of the polymer. Conversely, at higher temperatures (such as 40 degrees C), this polymer showed significant catalytic activity resulting from the dissociation of the interpolymer complexes between PVI and PTFMA, which facilitated access to the active sites of PVI and inflated the polymer. Unlike previously reported poly(N-isopropylacrylamide)-based molecularly imprinted polymers, which demonstrated decreased molecular recognition and catalytic activity with increased temperatures, i.e., negatively thermosensitive molecular recognition and catalysis abilities, this imprinted polymer exploits the unique interpolymer interaction between PVI and PTFMA, enabling the reversed thermal responsiveness.

  • 13.
    Tucker, Mark
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Bilek, Marcela M. M.
    University of Sydney, Australia .
    McKenzie, David R.
    University of Sydney, Australia .
    A combinatorial investigation of sputtered Ta-Al-C thin films2014In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 558, 99-103 p.Article in journal (Refereed)
    Abstract [en]

    We describe a combinatorial experiment investigating the Ta-Al-C material system, conducted with the aim of determining why the tantalum-containing M-n + (1)AX(n) phases have so far proved to be not amenable to thin-film synthesis. Samples were deposited onto (0001) Al2O3 wafers at 850 degrees C and characterized by X-ray diffraction wafer maps, scanning electron microscopy, and surface optical scattering. Elemental Ta, the binary phases TaC, Ta2C, and TaAl3, and the ternary phases Ta3Al2C and Ta5Al3C were identified. The morphology, phase composition and preferred orientation of the films deposited were found to be highly sensitive to the Ta fraction of the incident flux during deposition. No MAX phase material was observed, indicating that the Ta-containing MAX phases do not form under the deposition conditions investigated. Explanations associated with inadequate coverage of stochiometries, preferential sputtering, and thermodynamic instability have been ruled out. An explanation based on reduced surface diffusion of Ta during growth is proposed. A substantially higher substrate temperature during deposition is likely to be required to synthesize Ta-containing MAX phases.

  • 14.
    Sjöqvist, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    González-Cano, Rafael C.
    University of Málaga, Spain.
    López Navarette, Juan T.
    University of Málaga, Spain.
    Casado, Juan
    University of Málaga, Spain.
    Ruiz Delgado, M. Carmen
    University of Málaga, Spain.
    Linares, Mathieu
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Norman, Patrick
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    A combined MD/QM and experimental exploration of conformational richness in branched oligothiophenes2014In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 45, 24841-24852 p.Article in journal (Refereed)
    Abstract [en]

    Infrared (IR) absorption and vibrational Raman spectra of a family of branched oligothiophenes have been determined experimentally as well as theoretically. The molecular spectra have been compared to those of the linear analogues, with identification made of spectral features due to structural properties that are valued in organic solar cell applications. The theoretical spectra have been obtained through a newly developed method in which individual conformer spectra, calculated at the time-dependent DFT level in this work, are weighted by statistics extracted from classical molecular dynamics trajectories. The agreement with experiment for the resulting averaged spectra is at least as good as, and often better than, what is observed for Boltzmann-weighted spectra. As the weights are available before the costly step of spectrum calculation, the method has the additional advantage of enabling efficient approximations. For simulating the molecular dynamics of the studied α,β-linked thiophenes and 2-methylthiophenes, high quality parameters have been derived for the CHARMM force field. Furthermore, the temperature dependence of the IR and Raman spectra have been investigated, both experimentally and theoretically.

  • 15.
    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.

  • 16.
    Schmidt, Susann
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Czigany, Zsolt
    Hungarian Academic Science, Hungary.
    Wissting, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    A comparative study of direct current magnetron sputtering and high power impulse magnetron sputtering processes for CNX thin film growth with different inert gases2016In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 64, 13-26 p.Article in journal (Refereed)
    Abstract [en]

    Reactive direct current magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS) discharges of carbon in different inert gas mixtures (N-2/Ne, N-2/Ar, and N-2/Kr) were investigated for the growth of carbon-nitride (CNX) thin films. Ion mass spectrometry showed that energies of abundant plasma cations are governed by the inert gas and the N-2-to-inert gas flow ratios. The population of ion species depends on the sputter mode; HiPIMS yields approximately ten times higher flux ratios of ions originating from the target to process gas ions than DCMS. Exceptional are discharges in Ne with N-2-to-Ne flow ratios <20%. Here, cation energies and the amount of target ions are highest without influence on the sputter mode. CNX thin films were deposited in 14% N-2/inert gas mixtures at substrate temperatures of 110 degrees C and 430 degrees C. The film properties show a correlation to the substrate temperature, the applied inert gas and sputter mode. The mechanical performance of the films is mainly governed by their morphology and composition, but not by their microstructure. Amorphous and fullerene-like CN0.14 films exhibiting a hardness of similar to 15 GPa and an elastic recovery of similar to 90% were deposited at 110 degrees C in reactive Kr atmosphere by DCMS and HiPIMS.

  • 17.
    Karlsson, Laila
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    Milberg, Per
    Linköping University, Department of Physics, Chemistry and Biology, Ecology . Linköping University, The Institute of Technology.
    A Comparative Study of Germination Ecology of Four Papaver Taxa2007In: Annals of Botany, ISSN 0305-7364, Vol. 99, no 5, 935-946 p.Article in journal (Refereed)
    Abstract [en]

    Background and Aims: Comparative studies of closely related taxa can increase understanding of adaptations and changes in seed dormancy and germination preferences in an evolutionary perspective. For such studies, a method to describe and compare the performance of taxa in a general way is needed. The germination ecology of four Papaver taxa was studied with the aim of describing and comparing their responses to different seasonal temperature regimes.

    Methods: Germination of Papaver argemone, P. rhoeas, P. dubium ssp. dubium and P. dubium ssp. lecoqii was investigated in three different artificial climates over 2.5 years. Seeds were collected in southern Sweden, and samples from different populations were used as replicates of taxa.

    Key Results: Despite substantial intra-taxa variation, there were clear taxon-specific responses. Most germination occurred in the warmest climate. In general, the warmer the climate the more germination occurred in autumn instead of spring. Papaver argemone, phylogenetically most distant from the others, was, in contrast to the other taxa, restricted to germinating only at lower temperatures.

    Conclusions: Seed dormancy and germination may be described by dormancy pattern, germination preferences and dormancy strength. The general dormancy pattern was a common feature for these taxa and therefore probably an evolutionary conservative character. Germination preferences varied between taxa, resulting in different temperature optima and intervals for germination, and dormancy strength was to some extent taxon-specific, but highly variable. The dormancy pattern explained how the taxa can perform as winter annuals in warmer climates, but mainly as summer annuals in colder climates. Hence, there is no need to interpret the within-taxon temporal differences in seedling emergence as local adaptations. In the field, an entire seed cohort will not germinate during a single season. Instead, emergence will be distributed over several seasons, regardless of local climate, weather and soil cultivation methods.

  • 18.
    Sultana, Kishwar
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    ul Hasan, Kamran
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Alvi, N, H.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Klason, P.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A comparative study of the electrodeposition and the aqueous chemical growth techniques for the utilization of ZnO nanorods on p-GaN for white light emitting diodes2011In: Superlattices and Microstructures, ISSN 0749-6036, E-ISSN 1096-3677, Vol. 49, no 1, 32-42 p.Article in journal (Refereed)
    Abstract [en]

    Vertically well aligned zinc oxide nanorods (ZnO NRs) were grown on p-GaN by electrodeposition (ED) and aqueous chemical growth (ACG) techniques and the structures were employed to fabricate white light emitting diodes (LEDs). Room temperature current voltage (IV), photoluminescence (PL), and electroluminescence (EL) measurements were performed to investigate and compare both LEDs. In general, the IV characteristics and the PL spectra of both LEDs were rather similar. Nevertheless, the EL of the ED samples showed an extra emission peak shoulder at 730 nm. Moreover, at the same injection current, the EL spectrum of the ED light emitting diode showed a small UV shift of 12 nm and its white peak was found to be broader when compared to the ACG grown LED. The broadening of the EL spectrum of the LED grown by ED is due to the introduction of more radiative deep level defects. The presented LEDs have shown excellent color rendering indexes reaching a value as high as 95. These results indicate that the ZnO nanorods grown by both techniques possess very interesting electrical and optical properties but the ED is found to be faster and more suitable for the fabrication of white LEDs.

  • 19. Olafsson, HO
    et al.
    Hallin, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Sveinbjornsson, EO
    A comparison between SiO2/4H-SiC interface traps on (0001) and (1120) faces2004In: Materials Science Forum, ISSN 0255-5476, Vol. 457-460, 1305-1308 p.Article in journal (Refereed)
    Abstract [en]

    We present thermally stimulated current (TSC) measurements made on metal-oxide-semiconductor (MOS) structures fabricated on off-axis (0001) or on-axis (1120) face n-type 4H-SiC with wet or dry oxides. The TSC measurements show the interface trap spectra of traps with activation energies in the range from 0.1 to 0.6 eV. Varying the charging and discharging conditions, we are able to distinguish between two types of traps which are both present on (0001) and (1120) face samples. One type is sensitive to the electric field during discharging but is insensitive to the charging temperature, while the other type is insensitive to the electric field during discharging but can not capture electrons at low temperatures. We find that, compared to the (0001) face, the traps at the (1120) face are shifted in energy about 0.1 eV towards higher activation energies. In all cases, For wet or dry oxides made on the (0001) or the (1120) face, the number density of traps is above 7x10(12) cm(-2).

  • 20.
    Esamai, Fabian
    et al.
    Department of Child Health and Paediatrics, Faculty of Health Sciences, Moi University, Eldoret, Kenya.
    Mining, Simeon
    Department of Child Health and Paediatrics, Faculty of Health Sciences, Moi University, Eldoret, Kenya.
    Forsberg, Pia
    Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
    Lewis, David H.
    A comparison of brain, core and skin temperature in children with complicated and uncomplicated malaria2001In: Journal of Tropical Pediatrics, ISSN 0142-6338, E-ISSN 1465-3664, Vol. 47, no 3, 170-175 p.Article in journal (Refereed)
    Abstract [en]

    A prospective study was carried out in which brain, core and skin temperatures were studied in children with cerebral malaria (n = 23), uncomplicated malaria (n = 12) and normal children (n = 9) using the zero heat flow method. Patients with cerebral or uncomplicated malaria were admitted to the paediatric wards (mean age, 6 years 8 months ± 2 years 8 months). Normal children, children of the investigators, of the same age group, served as controls. Parasitaemia levels were similar in the cerebral and uncomplicated malaria cases. Higher brain than core temperatures would have been expected in cerebral malaria but not in uncomplicated malaria but this was not the case in this study. There was no statistical difference in brain, core and skin temperature between cerebral and uncomplicated malaria patients. However, there was a highly significant difference between normal children and cerebral and uncomplicated malaria patients. Brain temperature was 0.02–0.2°C below core temperature in all the groups with larger differences during the febrile period. Mean differences of brain minus core, brain minus skin and core minus skin between the two groups of patients were not statistically significant. There was no correlation between temperature and the level of coma or parasitaemia for cerebral and uncomplicated malaria patients. There was a positive correlation between brain and core temperature in both groups of patients during the febrile phase. Brain temperature remained lower than core temperature in cerebral and uncomplicated malaria as in normal children. Normal thermoregulation appears to be maintained in cerebral malaria.

  • 21.
    Esamai, Fabian
    et al.
    Department of Child Health and Paediatrics, Faculty of Health Sciences, Moi University, Eldoret, Kenya.
    Jivaji, S.
    Department of Human Pathology, Faculty of Health Sciences, Moi University, Eldoret, Kenya.
    Forsberg, Pia
    Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
    Lewis, David H.
    Anabwani, G. M.
    Department of Child Health and Paediatrics, Faculty of Health Sciences, Moi University, Eldoret, Kenya.
    A comparison of core and skin temperature among normal and febrile children with cerebral malaria, uncomplicated malaria, and measles1995In: Pathophysiology, ISSN 0928-4680, Vol. 2, no 1, 55-59 p.Article in journal (Refereed)
    Abstract [en]

    Forty-four children were studied to compare the pathogenesis of fever in cerebral malaria, uncomplicated malaria and measles at the Eldoret District Hospital (EDH). A control group of normal children was used. The three patient groups were studied for three consecutive days measuring skin and core temperature three-times a day using the Liquid Crystal Device (LCD) thermometer. A statistical analysis of the results within and between the groups was carried out for core and skin temperature over the study period. No statistical differences were found between the groups for either the skin or the core temperature, but a significant statistical difference was demonstrated between the core and the skin temperature for all of the groups for each of the three days. No statistical difference was found when the differences between the core and skin temperature were compared between cerebral malaria and uncomplicated malaria. The possible roles of fever in morbidity and mortality are discussed, with special reference to cerebral malaria.

  • 22.
    Diószegi, Attila
    et al.
    Department of Mechanical Engineering and Industrial Organisation / Component Technology, Jönköping University, Jönköping.
    Svensson, Ingvar L
    Department of Mechanical Engineering and Industrial Organisation / Component Technology, Jönköping University, Jönköping.
    A comparison of Fourier vs. Newtonian thermal analyse and its influence on the inverse kinetic growth calculationManuscript (preprint) (Other academic)
    Abstract [en]

    Thermal analysis of cooling curves is a metallurgical process control tool. Any phase transformations and their kinetics are reflected in the cooling rate. An interpretation of the cooling rate and temperatures is coupled to critical parameters, which are needed to assure correct quality of the melt and to give recommendations to modify the melt. This paper was inspired by the question, how well does a thermal ana lysis with one or two thermocouples and subsequent numerical analysis reflect the real phase transformations which occur?

    Inverse kinetic analysis using Fourier Thermal Analysis and Newtonian Thermal Analysis has been investigated using simulated cooling curves. The present study uses a direct simulation including a kinetic model for simulation of a eutectic phase. In this case, since the solidification sequence is well defined the inverse kinetic analysis should recreate the relation between the growth rate and supercooling of the eutectic phase. The Newtonian Thermal Analysis is based on an interpretation of a single thermal point with respect to solidification and contains a series of assumptions which are not entirely undoubted physically.

    Consequently the inverse kinetic analysis results in random quality growth parameters. The Fourier Thermal Analysis is based on interpretation of temperature differences between two thermal points with respect to solidification. The calculations conducted, in combination with the inverse kinetic analysis reveal a stable procedure. The decisive parameter determining the quality of inverse analysis is the distance between the thermal points analysed. Closely situated thermal points assure the best quality. The Fourier Thermal Analysis reflects the solidification most correctly.

  • 23.
    Ullbrand, Jennifer
    Linköping University, Department of Physics, Chemistry and Biology.
    A comparison of SPS  and HP sintered, electroless copper plated carbon nanofibre composites for heat sink applications2009Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    The aim of this study is to synthesize a material with high thermal conductivity and a low coefficient of thermal expansion (CTE), useful as a heat sink. Carbon nanofibres (CNF) are first coated with copper by an electroless plating technique and then sintered to a solid sample by either spark plasma sintering (SPS) or hot pressing (HP). The final product is a carbon nanofibre reinforced copper composite. Two different fibre structures are considered: platlet (PL) and herringbone (HB). The influence of the amount of CNF reinforcement (6-24 %wt), on the thermal conductivity and CTE is studied. CNF has an excellent thermal conductivity in the direction along the fibre while it is poor in the transverse direction. The CTE is close to zero in the temperature range of interest. The adhesion of Cu to the CNF surface is in general poor and thus improving the the wetting of the copper by surface modifications of the fibres are of interest such that thermal gaps in the microstructure can be avoided. The poor wetting results in CNF agglomerates, resulting in an inhomogeneous microstructure. In this report a combination of three different types of surface modifications has been tested: (1) electroless deposition of copper was used to improve Cu impregnation of CNF; (2) heat treatment of CNF to improve wetting; and (3) introduction of a Cr buffer layer to further enhance wetting. The obtained composite microstructures are characterized in terms of chemical composition, grain size and degree of agglomeration. In addition their densities are also reported. The thermal properties were evaluated in terms of thermal diffusivity, thermal conductivity and CTE. Cr/Cu coated platelet fibres (6wt% of CNF reinforcement) sintered by SPS is the sample with the highest thermal conductivity, ~200 W/Km. The thermal conductivity is found to decrease with increasing content of CNFs.

  • 24.
    Fornander, H.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Dannetun, Helen
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Ekedahl, L.-G.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    A comparison of the CO and D2 oxidation reactions on Pd supported on MgO(100), MgO(110) and MgO(111)1999In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 440, no 3, 375-386 p.Article in journal (Refereed)
    Abstract [en]

    Oxidation of D2 and CO on oxygen pre-exposed 200 nm thick Pd films, epitaxially grown on MgO(100), MgO(110) and MgO(111), has been investigated in the temperature range 100–300°C. Oxygen initial sticking coefficients have been determined to be close to 1 for the 100 and 110 films, and around 0.8 for the 111 film. The sticking coefficient and reactive sticking coefficient for CO oxidation on Pd/MgO(100) is also close to 1, and the maximum reactive sticking coefficient for hydrogen oxidation is determined to be around 0.9 at temperatures above 200°C. It is shown that the reactivities for the different surfaces vary strongly with surface and oxygen coverage, and the consequence of this for supported particle catalysts is pointed out.

  • 25.
    Nguyen, Son Tien
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Lindström, J. L.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    A complex defect related to the carbon vacancy in 4H and 6H SiC1999In: Physica Scripta, ISSN 0031-8949, Vol. T79, 46-49 p.Article in journal (Refereed)
    Abstract [en]

     Electron paramagnetic resonance (EPR) was used to study defects in 4H and 6H SiC irradiated with 2.5 MeV electrons at room temperature. When the dose of irradiation reaches ~ 5 × 1017 electrons/cm2, an EPR spectrum appears. In both 4H and 6H SiC, the defect associated with this spectrum has C1h symmetry with an effective electron spin S = 1 and an isotropic g-value of 2.0063 ± 0.0002. The crystal-field parameter was determined as D = 1.65 and D = 1.67 GHz for 4H and 6H SiC, respectively. The principal crystal-field axis lies in the (11bar 20) plane and makes an angle of ~ 46° with the c-axis for both polytypes. A clear hyperfine structure from 29Si due to the interaction with four nearest silicon neighbours was observed, confirming that the defect is related to the carbon vacancy. The similarity in all respects including the annealing behaviour of the spectrum in both polytypes suggests that it belongs to the same defect. Based on the formation and its electronic structure, the defect is suggested to be a complex with one of the components being the carbon vacancy.

  • 26.
    Johansson, Jonas
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Belov, Ilja
    Jönköping University, School of Engineering, Department of Mechanical Engineering, Jönköping.
    Johnson, Erland
    SP Technical Research Institute of Sweden, Borås, Sweden.
    Leisner, Peter
    SP Technical Research Institute of Sweden, Borås, Sweden.
    A computational method for evaluating the damage in a solder joint of an electronic package subjected to thermal loadsManuscript (preprint) (Other academic)
    Abstract [en]

    Purpose – The purpose of this paper is to introduce a novel computational method to evaluate damage accumulation in a solder joint of an electronic package, when exposed to operating temperature environment. A procedure to implement the method is suggested, and a discussion of the method and its possible applications is provided in the paper.

    Originality/value – The method enables increased accuracy in thermal fatigue life prediction of solder joints. Combined with other failure mechanisms, it may contribute to the accuracy of reliability assessment of electronic packages.

    Design/methodology/approach – Methodologically, interpolated response surfaces based on specially designed finite element simulation runs, are employed to compute a damage metric at regular time intervals of an operating temperature profile. The developed method has been evaluated on a finite-element model of a lead-free PBGA256 package, and accumulated creep strain energy density has been chosen as damage metric.

    Findings – The method has proven to be two orders of magnitude more computationally efficient compared to finite element simulation. A general agreement within 3% has been found between the results predicted with the new method, and finite element simulations when tested on a number of temperature profiles from an avionic application. The solder joint temperature ranges between +25°C and +75°C.

    Practical implications – The method can be implemented as part of reliability assessment of electronic packages in the design phase.

  • 27.
    Bengtsson, Mikael
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    A Control-Oriented 0D Model of a Turbocharger Gas Stand Including Heat Transfer2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A turbocharger’s performance is measured in a gas stand in order to provide information of the components characteristics. The measurement procedure is a very time consuming process and it is thus desired to make it more time-efficient.

    To allow for development of an enhanced control strategy used during the measurements, a 0D model of a gas stand is developed. The physical gas stand components are modeled and validated against measurements, all showing a reasonable result. Turbocharger heat transfers are investigated and modeled using a lumped capacitance approach. The heat transfer models shows approximative results when comparing with measurements which is explained by the lack of temperature measurement made on the bearing housing.

    When the complete gas stand model is validated against measurements, an improvement of the measurement procedure is examined. By adding an idealized heat source with the possibility to heat the compressor housing, it is possible to reduce the time it takes to reach an equilibrium when switching between two steady state operating points. 

  • 28.
    Öberg, Per
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    A DAE Formulation for Multi-Zone Thermodynamic Models and its Application to CVCP Engines2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the automotive area there are ever increasing demands from legislators and customers on low emissions and good fuel economy. In the process of developing and investigating new technologies, that can meet these demands, modeling and simulation have become important as standard engineering tools. To improve the modeling process new concepts and tools are also being developed.

    A formulation of a differential algebraic equation (DAE) that can be used for simulation of multi-zone in-cylinder models is extended and analyzed. Special emphasis is placed on the separation between thermodynamic state equations and the thermodynamic properties. This enables implementations with easy reuse of model components and analysis of simulation results in a structured manner which gives the possibility to use the formulation in a large number of applications. The introduction and depletion of zones are handled and it is shown that the DAE formulation has a unique solution as long as the gas model fulfills a number of basic criteria. Further, an example setup is used to validate that energy, mass, and volume are preserved when using the formulation in computer simulations. In other words, the numerical solution obeys the thermodynamic state equation and the first law of thermodynamics, and the results are consistent and converge as tolerances are tightened. As example applications, the DAE formulation is used to simulate spark ignited SI and Diesel engines as well as simple control volumes and 1-dimensional pipes. It is thus shown that the DAE formulation is able to adapt to the different requirements of the SI and Diesel engine models.

    An interesting application is the SI engine with continuously variable cam phasing (CVCP), which is a technology that reduces the fuel consumption. It influences the amount of air and residual gases in the engine in a non trivial manner and this SI application is used to evaluate three control oriented models for cylinder air charge and residual mass fraction for a CVCP-engine both for static and transient conditions. The models are: a simple generalized flow restriction model created with physical insight and two variants of a model that is based on an energy balance at intake valve closing (IVC). The two latter models require measurement of cylinder pressure and one also requires an air mass flow measurement. Using the SI model as reference it is shown that transients in cam positions have a large impact on air charge and residual mass fraction, and the ability of the models to capture these effects is evaluated. The main advantages of the generalized flow restriction model are that it is simple and does not require measurement of the cylinder pressure but it is also the model with the largest errors for static operating points and highest sensitivity in transients. The two models that use an energy balance at IVC both handle the transient cycles well. They are, however, sensitive to the temperature at IVC. For static cycles it is therefore advantageous to use the model with air mass flow measurement since it is less sensitive to input data. During transients however, if the external measurement is delayed, it is better to use the model that does not require the air mass flow.

    The conclusion is that the DAE formulation is a flexible, robust, tool, and that it is well suited for multi-zone in-cylinder models as well as models for manifolds and pipes outside the cylinder.

    List of papers
    1. Control Oriented Modeling of the Gas Exchange Process in Variable Cam Timing Engines
    Open this publication in new window or tab >>Control Oriented Modeling of the Gas Exchange Process in Variable Cam Timing Engines
    2006 (English)In: SAE Technical Paper 2006-01-0660, SAE , 2006Conference paper, Published paper (Refereed)
    Abstract [en]

    Variable cam timing engines pose new questions for engine control system designers. The cam timing directly influences cylinder air charge and residual mass fraction. Three models that predict residual mass fraction are investigated for a turbocharged dual independent Variable Cam Timing (VCT) engine. The three models (Fox et. al. 1993, Ponti et. al. 2002, and Mladek et. al. 2000) that all have real time capabilities are evaluated and validated against data from a crank angle based reference model. None of these models have previously been validated to cover this engine type. It is shown that all three models can be extended to dual independent VCT engines and that they also give a good description of the residual gas fraction. However, it is shown that the two most advanced models, based on a thermodynamic energy balance, are very sensitive to the model inputs and proper care must therefore be taken when these models are used

    Place, publisher, year, edition, pages
    SAE, 2006
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-18306 (URN)
    Available from: 2009-05-18 Created: 2009-05-18 Last updated: 2009-10-14Bibliographically approved
    2. Control Oriented Gas Exchange Models for CVCP Engines and their Transient Sensitivity
    Open this publication in new window or tab >>Control Oriented Gas Exchange Models for CVCP Engines and their Transient Sensitivity
    2007 (English)In: Oil & gas science and technology, ISSN 1294-4475, Vol. 62, no 4, 573-584 p.Article in journal (Refereed) Published
    Abstract [en]

    The paper analyzes a set of control oriented models for the gas exchange phase in engines with continuously variable cam phasing (CVCP). These models describe the mass flow of fresh gases and the residual gases caught in the cylinder during the gas exchange phase. Simulations with CVCP transients are also performed to analyze the models performance during transients.

    Place, publisher, year, edition, pages
    IFP, 2007
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-18307 (URN)10.2516/ogst:2007041 (DOI)
    Available from: 2009-05-18 Created: 2009-05-18 Last updated: 2009-05-18Bibliographically approved
  • 29.
    Berntsson, Fredrik
    et al.
    Linköping University, Department of Mathematics, Applied Mathematics. Linköping University, The Institute of Technology.
    Mpinganzima, Lydie
    National University of Rwanda, Box 117, Butare, Rwanda.
    A Data Assimilation Approach to Coefficient Identification2011Report (Other academic)
    Abstract [en]

    The thermal conductivity properties of a material can be determined experimentally by using temperature measurements taken at specified locations inside the material. We examine a situation where the properties of a (previously known) material changed locally. Mathematically we aim to find the coefficient k(x) in the stationary heat equation (kTx)x = 0;under the assumption that the function k(x) can be parametrized using only a few degrees of freedom.

    The coefficient identification problem is solved using a least squares approach; where the (non-linear) control functional is weighted according to the distribution of the measurement locations. Though we only discuss the 1D case the ideas extend naturally to 2D or 3D. Experimentsdemonstrate that the proposed method works well.

     

     

     

     

  • 30.
    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.

  • 31.
    Johansson, Jimmy
    Linköping University, Department of Physics, Chemistry and Biology.
    A first principles study of the thermodynamics of phase separating systems -The examples RhPd and AlZn-2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A screened GPM approach in an EMTO-CPA framework was investigated in order to study its ability of describing transition temperatures in phase separating systems, i. e. systems giving either a random or a cluster structure depending on the temperature and the relative concentration of the ingoing atoms of the binary alloy used for the study. A motivation for the study is that the method works well for ordering systems, i. e. systems giving either a random or ordered structure dependent on the temperature and the relative concentration of the components in the binary alloy. Thereby is it of interest to find out the methods capacity in phase separating systems. The so called GPM potentials derived in the approach were applied in statistical Monte Carlo simulations for this purpose. The systems chosen for the investigation were the RhPd and the AlZn binary alloy systems. For both systems the method showed acceptable accuracy when properties as lattice parameter and mixing enthalpy were calculated. The quality of the derived GPM potentials has also been checked by calculating ordering energy for different ordered structures; directly from first principles calculations and from the GPM approach. The results were in acceptable agreement and thereby indicating that the GPM potentials were reliable. The transition temperatures in the RhPd phase diagram, derived by the statistical Monte Carlo simulations showed anyway deviation from experimental results. The error in the predictions might be due to the existing concentration dependencies in the GPM potentials.The conclusion from this study is that the Monte Carlo scheme might be inconvenient in order to handle the concentration dependencies seen in the GPM potentials.

  • 32.
    Klarbring, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    A first-principles non-equilibrium molecular dynamicsstudy of oxygen diffusion in Sm-doped ceria2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Solid oxide fuel cells are considered as one of the main alternatives for future sources of clean energy. To further improve their performance, theoretical methods able to describe the diffusion process in candidate electrolyte materials at finite temperatures are needed. The method of choice for simulating systems at finite temperature is molecular dynamics. However, if the forces are calculated directly from the Schrödinger equation (first-principles molecular dynamics) the computational expense is too high to allow long enough simulations to properly capture the diffusion process in most materials.

    This thesis introduces a method to deal with this problem using an external force field to speed up the diffusion process in the simulation. The method is applied to study the diffusion of oxygen ions in Sm-doped ceria, which has showed promise in its use as an electrolyte. Good agreement with experimental data is demonstrated, indicating high potential for future applications of the method.

  • 33.
    Satti Osman, Eiman
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Chey, Chan Oeurn
    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.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    A flexible anisotropic self-powered piezoelectric direction sensor based on double sided ZnO nanowires configuration2015In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 26, no 9, 095502Article in journal (Refereed)
    Abstract [en]

    We have successfully synthesized highly dense and well aligned zinc oxide nanowires (NWs) on the two sides of a PEDOT: PSS substrate by a single step low temperature hydrothermal method. The grown sample was used to fabricate a double sided piezoelectric nanogenerator (NG). The maximum harvested output power density from the fabricated double sided NG configuration was about 4.44 mW cm(-2). The results obtained from the present double sided NG were approximately double the output from a single side. In addition to that, the voltage polarity of the harvested voltage from the two sides of the NG has been investigated. The results showed that upon bending, an anisotropic voltage polarity is generated on the two sides. Indicating that, this double sided NG can be used as a self-powered voltage polarity based direction sensor. The results of the present flexible double sided NG is very promising for harvesting energy from irregular mechanical energy sources in the surrounding environment. In addition, the fabricated configuration showed stability for sensing and can be used in surveillance and security applications.

  • 34.
    Diaz de Zerio Mendaza, Amaia
    et al.
    Chalmers, Sweden.
    Melianas, Armantas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Nugroho, Ferry A. A.
    Chalmers, Sweden.
    Backe, Olof
    Chalmers, Sweden.
    Olsson, Eva
    Chalmers, Sweden.
    Langhammer, Christoph
    Chalmers, Sweden.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mueller, Christian
    Chalmers, Sweden.
    A fullerene alloy based photovoltaic blend with a glass transition temperature above 200 degrees C2017In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 8, 4156-4162 p.Article in journal (Refereed)
    Abstract [en]

    Organic solar cells with a high degree of thermal stability require bulk-heterojunction blends that feature a high glass transition, which must occur considerably above the temperatures encountered during device fabrication and operation. Here, we demonstrate for the first time a polymer : fullerene blend with a glass transition temperature above 200 degrees C, which we determine by plasmonic nanospectroscopy. We achieve this strong tendency for glass formation through the use of an alloy of neat, unsubstituted C-60 and C-70, which we combine with the fluorothieno-benzodithiophene copolymer PTB7. A stable photovoltaic performance of PTB7 : C60 : C70 ternary blends is preserved despite annealing the active layer at up to 180 degrees C, which coincides with the onset of the glass transition. Rapid deterioration of the power conversion efficiency from initially above 5% only occurs upon exceeding the glass transition temperature of 224 degrees C of the ternary blend.

  • 35.
    Harikumar, Prakash
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Wikner, Jacob
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    A fully-differential OTA in 28 nm UTBB FDSOI CMOS for PGA applications2015In: 2015 European Conference on Circuit Theory and Design (ECCTD), IEEE , 2015, 13-16 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a fully-differential operational transconductance amplifier (OTA) designed in a 28 nm ultra-thin box and body (UTBB) fully-depleted silicon-on-insulator (FDSOI) CMOS process. An overview of the features of the 28 nm UTBB FDSOI process which are relevant for the design of analog/mixed-signal circuits is provided. The OTA which features continuous-time CMFB circuits will be employed in the programmable gain amplifier (PGA) for a 9-bit, 1 kS/s SAR ADC. The reverse body bias (RBB) feature of the FDSOI process is used to enhance the DC gain by 6 dB. The OTA achieves rail-to-rail output swing and provides DC gain = 70 dB, unity-gain frequency = 4.3 MHz and phase margin = 68ï¿œ while consuming 2.9 μW with a Vdd = 1 V. A high linearity > 12 bits without the use of degeneration resistors and a settling time of 5.8 μs (11-bit accuracy) are obtained under nominal operating conditions. The OTA maintains satisfactory performance over all process corners and a temperature range of [-20oC +85oC].

  • 36.
    Gokulakrishnan, P
    et al.
    Queens University, Canada.
    Lawrence, David
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    McLellan, PJ
    Queens University, Canada.
    Grandmaison, EW
    Queens University, Canada.
    A functional-PCA approach for analyzing and reducing complex chemical mechanisms2006In: Computers and Chemical Engineering, ISSN 0098-1354, Vol. 30, no 07-Jun, 1093-1101 p.Article in journal (Refereed)
    Abstract [en]

    In industrial reactive flow systems such as furnaces and gas turbines, there are considerable variations in the temperature and concentrations of species along different spatial directions. Functional principal component analysis (fPCA) can be used to study the temporal (or spatial) evolution of reactions in a reactive flow system, and to develop simplified kinetic models to describe this behaviour. A comprehensive kinetic mechanism for CO oxidation is used to demonstrate application of fPCA to identify important reactions as a function of time. In conventional PCA, the eigenvalue-eigenvector decomposition specifically transforms the variations associated with the time (or spatial directions) and species into loadings that represent only the reactions. However, fPCA produces functional loading vectors (xi) over bar (1)(t) which are functions of time or distance, whose elements are referred to as functional loadings. The functional loading vectors are the eigenfunctions of the covariance matrix associated with the sensitivity trajectories. The functional loadings are used to identify reactions playing a significant role, possibly as a function of time, and are used to develop a reduced kinetic scheme from a detailed kinetic mechanism.

  • 37.
    Lunner, Thomas
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences. Eriksholm Research Centre, Oticon A/S, Snekkersten, Denmark.
    A hearing aid system comprising EEG electrodes.2013Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The invention relates to a hearing aid system for obtaining an ambulatory electroencephalogram, EEG, comprising two or more electric terminals in the surface of a hearing instrument shell where it contacts the skin inside or outside the ear canal. The electrical terminals may all serve the same purpose (e.g. measuring EEG) or different purposes (e.g. three for measuring EEG and one for measuring body temperature).

  • 38.
    He, Zhiyuan
    et al.
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, The Institute of Technology.
    Peng, Zebo
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, The Institute of Technology.
    Eles, Petru Ion
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, The Institute of Technology.
    A heuristic for thermal-safe SoC test scheduling2007In: IEEE International Test Conference, 2007, IEEE , 2007, 116-125 p.Conference paper (Refereed)
    Abstract [en]

    High temperature has become a technological barrier to the testing of high performance systems-on-chip, especially when deep submicron technologies are employed. In order to reduce test time while keeping the temperature of the cores under test within a safe range, thermal-aware test scheduling techniques are required. In this paper, we address the test time minimization problem as how to generate the shortest test schedule such that the temperature limits of individual cores and the limit on the test-bus bandwidth are satisfied. In order to avoid overheating during the test, we partition test sets into shorter test sub-sequences and add cooling periods in between, such that continuously applying a test sub-sequence will not drive the core temperature going beyond the limit. Further more, based on the test partitioning scheme, we interleave the test sub-sequences from different test sets in such a manner that a cooling period reserved for one core is utilized for the test transportation and application of another core. We have proposed a heuristic to minimize the test application time by exploring alternative test partitioning and interleaving schemes with variable length of test sub-sequences and cooling periods. Experimental results have shown the efficiency of the proposed heuristic.

  • 39.
    Berg, Kirsti
    et al.
    Norwegian University of Science and Technology, Trondheim, Norway.
    Ericsson, Madelene
    Umeå University, Sweden.
    Lindgren, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology. Norwegian University of Science and Technology, Trondheim, Norway.
    Gustafsson, Håkan
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Biomedical Engineering.
    A High Precision Method for Quantitative Measurements of Reactive Oxygen Species in Frozen Biopsies2014In: PLoS ONE, ISSN 1932-6203, Vol. 9, no 3Article in journal (Refereed)
    Abstract [en]

    Objective

    An electron paramagnetic resonance (EPR) technique using the spin probe cyclic hydroxylamine 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetr​amethylpyrrolidine(CMH) was introduced as a versatile method for high precision quantification of reactive oxygen species, including the superoxide radical in frozen biological samples such as cell suspensions, blood or biopsies.

    Materials and Methods

    Loss of measurement precision and accuracy due to variations in sample size and shape were minimized by assembling the sample in a well-defined volume. Measurement was carried out at low temperature (150 K) using a nitrogen flow Dewar. The signal intensity was measured from the EPR 1st derivative amplitude, and related to a sample, 3-carboxy-proxyl (CP•) with known spin concentration.

    Results

    The absolute spin concentration could be quantified with a precision and accuracy better than ±10 µM (k = 1). The spin concentration of samples stored at −80°C could be reproduced after 6 months of storage well within the same error estimate.

    Conclusion

    The absolute spin concentration in wet biological samples such as biopsies, water solutions and cell cultures could be quantified with higher precision and accuracy than normally achievable using common techniques such as flat cells, tissue cells and various capillary tubes. In addition; biological samples could be collected and stored for future incubation with spin probe, and also further stored up to at least six months before EPR analysis, without loss of signal intensity. This opens for the possibility to store and transport incubated biological samples with known accuracy of the spin concentration over time.

  • 40.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    A hybrid equation for simulation of perfused tissue during thermal treatment2001In: International Journal of Hyperthermia, ISSN 0265-6736, Vol. 17, no 6, 483-498 p.Article in journal (Refereed)
    Abstract [en]

    Bio-heat equations (BHEs) are necessary for predicting tissue temperature during thermal treatment. For some applications, however, existing BHEs describe the convective heat transfer by the blood perfusion in an unsatisfactory way. The two most frequently used equations, the BHE of Pennes and the keff equation, use for instance either a heat sink or an increased thermal conductivity in order to account for the blood perfusion. Both these methods introduce modelling inaccuracies when applied to an ordinary tissue continuum with a variety of vessel sizes. In this study, a hybrid equation that includes both an increased thermal conductivity and a heat sink is proposed. The equation relies on the different thermal characteristics associated with small, intermediate and large sized vessels together with the possibilities of modelling these vessels using an effective thermal conductivity in combination with a heat sink. The relative importance of these two terms is accounted for by a coefficient ▀. For ▀ = 0 and ▀ = 1, the hybrid equation coincides with the BHE of Pennes and the keff equation, respectively. The hybrid equation is used here in order to simulate temperature fields for two tissue models. The temperature field is greatly affected by ▀, and the effect is dependent on, e.g. the boundary conditions and the power supply. Since the BHE of Pennes and the keff equation are included in the hybrid equation, this equation can also be useful for evaluation of the included equations. Both these heat transfer modes are included in the proposed equation, which enables implementation in standard thermal simulation programmes.

  • 41.
    Sahlberg, Jörgen
    Swedish Meteorological and Hydrological Institute, Norrköping, Sweden.
    A Hydrodynamical Model for Calculating the Vertical Temperature Profile in Lakes During Cooling1983In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 14, no 4, 239-254 p.Article in journal (Refereed)
    Abstract [en]

    A one-dimensional hydrodynamical model is used for simulating the vertical temperature profile in a lake during cooling conditions. The vertical mixing rate is calculated by solving the equations for turbulent kinetic energy, k, and dissipation of energy, ε. The heat exchange between the water and atmosphere consists of the radiation fluxes, sensible and latent heat flux. Temperature measurements from Lake Väsman during November-December, 1981, were used in the verification study. The agreement between calculated and measured temperature profiles is very good. This indicates that both the mixing processes and the net heat flux are well described in the model.

  • 42. Fogelberg, J.
    et al.
    Dannetun, Helen
    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.
    Petersson, L.-G.
    A hydrogen sensitive palladium metal-oxide-semiconductor device as sensor for dissociating NO in H2-atmospheres1990In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 41, 705- p.Article in journal (Refereed)
    Abstract [en]

    A Pd-MOS structure can be used as a sensitive analytical tool in the study of dissociating oxygen containing molecules. Nitric oxide has been studied as a test case. Initially NO adsorbs very effectively and dissociatively on polycrystalline Pd at temperatures above 473 K. At this temperature H2O, N2O and N2 desorbs during an NO exposure in a hydrogen background. After such exposure the surface is probably left with only residual nitrogen atoms adsorbed on the surface. Below 390 K the dissociation probability is insignificant.

  • 43.
    Jirstrand, Mats
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Spångéus, Per
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    A Linear Programming Approach to the Design of Thermostat Controllers of Interconnected Thermal Systems1998Report (Other academic)
    Abstract [en]

    We investigate how to tune the thermostat hysteresis for a system of interconnected thermal processes. Using linear programming techniques and the worst-case analysis we compute switch levels for the controller to make the system stay close to the desired temperature levels. Both the cases with and without amplitude bounded disturbances are treated. The same technique can also be applied to a system of interconnected tanks despite the fact that such a system is nonlinear.

  • 44.
    Jirstrand, Mats
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Spångéus, Per
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    A Linear Programming Approach to the Design of Thermostat Controllers of Interconnected Thermal Systems1998In: Proceedings of the First Conference on Computer Science and Systems Engineering, 1998, 47-54 p.Conference paper (Other academic)
    Abstract [en]

    In this note we investigate how to tune the thermostat hysteresis for a system of interconnected thermal processes. Using linear programming techniques and worst-case analysis we compute switch levels for the controller to make the system stay close to desired temperature levels. Both the case with and without amplitude bounded disturbances are treated. The same technique can also be applied to a system of interconnected tanks despite the fact that such a system is nonlinear.

  • 45.
    Jirstrand, Mats
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Spångéus, Per
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    A Linear Programming Approach to the Design of Thermostat Controllers of Interconnected Thermal Systems1998In: Proceedings of the 37th IEEE Conference on Decision and Control, 1998, 449-454 p.Conference paper (Refereed)
    Abstract [en]

    We investigate how to tune the thermostat hysteresis for a system of interconnected thermal processes. Using linear programming techniques and the worst-case analysis we compute switch levels for the controller to make the system stay close to the desired temperature levels. Both the cases with and without amplitude bounded disturbances are treated. The same technique can also be applied to a system of interconnected tanks despite the fact that such a system is nonlinear.

  • 46.
    Lundström, Erik
    et al.
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, The Institute of Technology.
    Simonsson, Kjell
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, The Institute of Technology.
    Gustafsson, David
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, The Institute of Technology.
    Månsson, T.
    GKN Aerospace Engine Systems, Trollhättan, Sweden.
    A load history dependent model for fatigue crack propagation in Inconel 718 under hold time conditions2014In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 118, 17-30 p.Article in journal (Refereed)
    Abstract [en]

    Modelling of high temperature fatigue crack growth in Inconel 718 under the interaction of fast cyclic loading and hold times at maximum load has been conducted. A model, based on the concept of a damaged zone in front of the crack tip has been applied for three different temperatures, 550, 600 and 650 ◦C, with good agreement for both calibration and validation tests. A statistical evaluation of 22 tests in total was also conducted, which shows that the developed model gives a reasonable scatter factor at a probability of failure of 0.1 %.

  • 47.
    Mesgarzadeh, Behzad
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Sadeghifar, Mohammad Reza
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Fredriksson, P.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Jansson, C.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Niklaus, F.
    FAUN AB.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A low-noise readout circuit in 0.35-μm CMOS for low-cost uncooled FPA infrared network camera2009In: Proceedings of SPIE - The International Society for Optical Engineering, vol 7298, SPIE - International Society for Optical Engineering, 2009, Vol. 7298, 72982F- p.Conference paper (Refereed)
    Abstract [en]

    This paper describes a differential readout circuit technique for uncooled Infrared Focal Plane Arrays (IRFPA) sensors. The differential operation allows an efficient rejection of the common-mode noise during the biasing and readout of the detectors. This has been enabled by utilizing a number of blind and thermally-isolated IR bolometers as reference detectors. In addition, a pixel-wise detector calibration capability has been provided in order to allow efficient error corrections using digital signal processing techniques. The readout circuit for a 64×64 test bolometer-array has been designed in a standard 0.35-μm CMOS process. Circuit simulations show that the analog readout at 60 frames/s consumes 30 mW from a 3.3-V supply and results in a noise equivalent temperature difference (NETD) of 125 mK for f/1 infrared optics.

  • 48.
    Meshkian, Rahele
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ingason, Arni Sigurdur
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Arnalds, U. B.
    University of Iceland, Iceland.
    Magnus, F.
    Uppsala University, Sweden.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    A magnetic atomic laminate from thin film synthesis: (Mo0.5Mn0.5)2GaC2015In: APL MATERIALS, ISSN 2166-532X, Vol. 3, no 7, 076102Article in journal (Refereed)
    Abstract [en]

    We present synthesis and characterization of a new magnetic atomic laminate: (Mo0.5Mn0.5)(2)GaC. High quality crystalline films were synthesized on MgO(111) substrates at a temperature of similar to 530 degrees C. The films display a magnetic response, evaluated by vibrating sample magnetometry, in a temperature range 3-300 K and in a field up to 5 T. The response ranges from ferromagnetic to paramagnetic with change in temperature, with an acquired 5T-moment and remanent moment at 3 K of 0.66 and 0.35 mu(B) per metal atom (Mo and Mn), respectively. The remanent moment and the coercive field (0.06 T) exceed all values reported to date for the family of magnetic laminates based on so called MAX phases.

  • 49.
    Ingeström, Victor
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Hansson, John
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    A Method for Estimating Soot Load in a DPF using an RF-based Sensor2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The European emission standard is an EU directive which describes what emission limits car manufactures are required to meet. In order to meet these requirements car manufacturers use different techniques and components. In a modern diesel automobile a Diesel Particulate Filter (DPF) is used to gather soot from the exhausts. As soot accumulates in the DPF, the back pressure increases and the capability to hold more soot decreases. Therefore the DPF continuously needs to get rid of the stored soot. The soot is removed through a process called regeneration. In order to optimize when to perform regeneration, it is vital to know the amount of soot in the filter.

    A method for estimating the soot mass in a DPF using a radio frequency-based sensor has been developed. The sensor that has been studied is the Accusolve soot sensor from General Electric. A parameter study has been performed to evaluate the parameters that affects the sensor’s output. Parameters that have been studied include positioning of the sensor, temperature in the DPF, flow rate through the DPF and distribution of soot in the DPF. Different models for estimation of soot mass in the DPF has been developed and analyzed.

    An uncertainty caused by removing the coaxial cable connectors when weighing the DPF has been identified and methods for minimizing this uncertainty has been presented. Results show that the sensor output is sensitive to temperature, soot distribution and position, and also show some sensitivity to the flow rate. An ARX model, with only one state, is proposed to estimate the soot mass in the DPF, since it gives the best prediction of soot mass and showed good resistance to bias errors and noise in all the input signals.

  • 50.
    Rejmstad, Peter
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, Faculty of Science & Engineering.
    Johansson, Johannes D.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, Faculty of Science & Engineering.
    Haj-Hosseini, Neda
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, Faculty of Science & Engineering.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, Faculty of Science & Engineering.
    A method for monitoring of oxygen saturation changes in brain tissue using diffuse reflectance spectroscopy2017In: Journal of Biophotonics, ISSN 1864-063X, E-ISSN 1864-0648, Vol. 10, no 3, 446-455 p.Article in journal (Refereed)
    Abstract [en]

    Continuous measurement of local brain oxygen saturation (SO2) can be used to monitor the status of brain trauma patients in the neurocritical care unit. Currently, micro-oxygen-electrodes are considered as the “gold standard” in measuring cerebral oxygen pressure (pO2), which is closely related to SO2 through the oxygen dissociation curve (ODC) of hemoglobin, but with the drawback of slow in response time. The present study suggests estimation of SO2 in brain tissue using diffuse reflectance spectroscopy (DRS) for finding an analytical relation between measured spectra and the SO2 for different blood concentrations. The P3 diffusion approximation is used to generate a set of spectra simulating brain tissue for various levels of blood concentrations in order to estimate SO2. The algorithm is evaluated on optical phantoms mimicking white brain matter (blood volume of 0.5–2%) where pO2 and temperature is controlled and on clinical data collected during brain surgery. The suggested method is capable of estimating the blood fraction and oxygen saturation changes from the spectroscopic signal and the hemoglobin absorption profile.

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