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  • 1.
    Kuei, Chun-Fu
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Transmission electron microscopy study on the formation of SiNX interlayer during InAlN growth on Si (111) substrate2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ternary indium aluminum nitride (InXAl1-XN) semiconductor is an attractive material with a wide-range bandgap energy varied from ultraviolet (Eg(AlN): 6.2 eV) to near infrared (Eg(InN): 0.7 eV). With tuning composition, it can be widely used to many optoelectronic device applications. In this thesis, I have studied InXAl1-XN film deposited on Si (111) substrate using natural and isotopically enriched nitrogen as reactive gas by reactive magnetron sputter epitaxy (MSE). Four series of experiments were performed, which are I. InAlN presputtering, II. InAlN sputter deposition, III. InAlN direct deposition, and IV. InAlN direct deposition using isotopically enriched nitrogen. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The θ-2θ XRD scan confirms that the designed composition x = 0.17 of InXAl1-XN film was obtained. TEM images shows that an amorphous interlayer with a thickness ranging from 1.2 nm to 1.5 nm was formed between Si substrate and InXAl1-XN film. However, high-resolution TEM shows that the interlayer actually contains partial crystalline structures. EDX line profile indicates that the chemical composition of the amorphous interlayer is silicon nitride (SiNX). By comparing d-spacing measurement of partial crystalline structures with EDX line profile, it reveals that partial SiNX crystal is formed in the interlayer. Nonetheless, the samples (IAD01, IAD02, IAD03, IAD04), grown without presputtering procedure, contain both crystalline SiNX and InXAl1-XN embedded in the amorphous interlayer. It means that SiNX and InXAl1-XN film can be directly grown on the substrate in the beginning of deposition. Moreover, the samples (IAD01, IAD03), quenched directly after deposition, have less crystalline structures in the interlayer then the samples (IAD02, IAD04), maintained at 800℃ for 20 min.

  • 2.
    Aevan, Nadjib Danial
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems.
    MDO Framework for Design of Human PoweredPropellers using Multi-Objective Genetic Algorithm2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis showcases the challenges, downsides and advantages to building a MultiDisciplinary Optimization (MDO) framework to automate the generation of an efficientpropeller design built for lightly loaded operation, more specifically for humanpowered aircrafts. Two years ago, a human powered aircraft project was initiatedat Linköping University. With the help of several courses, various students performedconceptional design, calculated and finally manufactured a propeller bymeans of various materials and manufacturing techniques. The performance ofthe current propeller is utilized for benchmarking and comparing results obtainedby the MDO process.The developed MDO framework is constructed as a modeFRONITER project wereseveral Computer Aided Engineering softwares (CAE) such as MATLAB, CATIAand XFOIL are connected to perform multiple consequent optimization subprocesses.The user is presented with several design constraints such as blade quantity,required input power, segment-wise airfoil thickness, desired lift coefficientetc. Also, 6 global search optimization algorithms are investigated to determinethe one which generate most efficient result according to several set standards.The optimization process is thereafter initialized by identifying the most efficientchord distribution with a help of an initial blade cross-section which has been previouslyused in other human powered propellers, the findings are thereafter usedto determine the flow conditions at different propeller stations. Two different aerodynamicoptimized shapes are generated with the help of consecutively performedsubprocesses. The optimized propeller requires 7.5 W less input power to generatenearly equivalent thrust as the original propeller with a total efficiency exceedingthe 90 % mark (90.25 %). Moreover, the MDO framework include an automationprocess to generate a CAD design of the optimized propeller. The generatedCAD file illustrates a individual surface blade decrease of 12.5 % compared tothe original design, the lightweight design and lower input power yield an overallpropulsion system which is less tedious to operate.

  • 3.
    Tardif, Jean-Claude
    et al.
    Université de Montréal Beaulieu-Saucier Pharmacogenomics, Centre Montreal, Quebec, Canada.
    Rhéaume, Eric
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Lemieux Perreault, Louis-Philippe
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Grégoire, Jean C
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Feroz Zada, Yassamin
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Asselin, Géraldine
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Provost, Sylvie
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Barhdadi, Amina
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Rhainds, David
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    L'Allier, Philippe L
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Ibrahim, Reda
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Upmanyu, Ruchi
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Niesor, Eric J
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Benghozi, Renée
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Suchankova, Gabriela
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Laghrissi-Thode, Fouzia
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Guertin, Marie-Claude
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Olsson, Anders G
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Mongrain, Ian
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Schwartz, Gregory G
    University of Colorado, Denver, USA and F. Hoffmann-La Roche, Basel, Switzerland.
    Dubé, Marie-Pierre
    Université de Montréal Beaulieu-Saucier Pharmacogenomics, Centre Montreal, Quebec, Canada.
    Pharmacogenomic determinants of the cardiovascular effects of dalcetrapib.2015In: Circulation: Cardiovascular Genetics, ISSN 1942-325X, E-ISSN 1942-3268, Vol. 8, no 2, 372-382 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Dalcetrapib did not improve clinical outcomes, despite increasing high-density lipoprotein cholesterol by 30%. These results differ from other evidence supporting high-density lipoprotein as a therapeutic target. Responses to dalcetrapib may vary according to patients' genetic profile.

    METHODS AND RESULTS: We conducted a pharmacogenomic evaluation using a genome-wide approach in the dal-OUTCOMES study (discovery cohort, n=5749) and a targeted genotyping panel in the dal-PLAQUE-2 imaging trial (support cohort, n=386). The primary endpoint for the discovery cohort was a composite of cardiovascular events. The change from baseline in carotid intima-media thickness on ultrasonography at 6 and 12 months was evaluated as supporting evidence. A single-nucleotide polymorphism was found to be associated with cardiovascular events in the dalcetrapib arm, identifying the ADCY9 gene on chromosome 16 (rs1967309; P=2.41×10(-8)), with 8 polymorphisms providing P<10(-6) in this gene. Considering patients with genotype AA at rs1967309, there was a 39% reduction in the composite cardiovascular endpoint with dalcetrapib compared with placebo (hazard ratio, 0.61; 95% confidence interval, 0.41-0.92). In patients with genotype GG, there was a 27% increase in events with dalcetrapib versus placebo. Ten single-nucleotide polymorphism in the ADCY9 gene, the majority in linkage disequilibrium with rs1967309, were associated with the effect of dalcetrapib on intima-media thickness (P<0.05). Marker rs2238448 in ADCY9, in linkage disequilibrium with rs1967309 (r(2)=0.8), was associated with both the effects of dalcetrapib on intima-media thickness in dal-PLAQUE-2 (P=0.009) and events in dal-OUTCOMES (P=8.88×10(-8); hazard ratio, 0.67; 95% confidence interval, 0.58-0.78).

    CONCLUSIONS: The effects of dalcetrapib on atherosclerotic outcomes are determined by correlated polymorphisms in the ADCY9 gene.

    CLINICAL TRIAL INFORMATION: URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00658515 and NCT01059682.

  • 4.
    Fernlund, Eva
    et al.
    Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Paediatrics in Linköping. Lund University, Sweden.
    Schlegel, Todd T.
    Karolinska Institute, Sweden; Karolinska University Hospital, Sweden.
    Platonov, Pyotr G.
    Lund University, Sweden.
    Carlson, Jonas
    Lund University, Sweden.
    Carlsson, Marcus
    Lund University, Sweden.
    Liuba, Petru
    Lund University, Sweden.
    Peripheral microvascular function is altered in young individuals at risk for hypertrophic cardiomyopathy and correlates with myocardial diastolic function2015In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 308, no 11, H1351-H1358 p.Article in journal (Refereed)
    Abstract [en]

    Hypertrophic cardiomyopathy (HCM) is a major cause of sudden cardiac death in the young. Based on previous reports of functional abnormalities in not only coronary but also peripheral vessels in adults with HCM, we aimed to assess both peripheral vascular and myocardial diastolic function in young individuals with an early stage of HCM and in individuals at risk for HCM. Children, adolescents, and young adults (mean age: 12 yr) with a family history of HCM who either had (HCM group; n = 36) or did not have (HCM-risk group; n = 30) echocardiography-documented left ventricular (LV) hypertrophy as well as healthy matched controls (n = 85) and healthy young athletes (n = 12) were included in the study. All underwent assessment with 12-lead electrocardiography, two-dimensional echocardiography, tissue Doppler imaging and laser Doppler with transdermal iontophoresis of ACh and sodium nitroprusside. LV thickness and mass were increased in HCM and athlete groups compared with control and HCM-risk groups. The mitral E-to-e ratio, measured via tissue Doppler, was increased in HCM (P less than 0.0001) and HCM-risk (P less than 0.01) groups compared with control and athlete groups, as were microvascular responses to ACh (HCM group: P less than 0.045 and HCM- risk group: P less than 0.02). Responses to ACh correlated with the E-to-e ratio (r = 0.5, P = 0.001). Microvascular responses to sodium nitroprusside were similar in all groups (P = 0.2). HCM-causing mutations or its familial history are associated with changes in cardiac diastolic function and peripheral microvascular function even before the onset of myocardial hypertrophy. Tissue Doppler can be used to differentiate HCM from physiological LV hypertrophy in young athletes.

  • 5. Varelogianni, Georgia
    et al.
    Hussain, Rashida
    Strid, Hilja
    Oliynyk, Igor
    Roomans, Godfried M
    Johannesson, Marie
    The effect of ambroxol on chloride transport, CFTR and ENaC in cystic fibrosis airway epithelial cells.2013In: Cell Biology International, ISSN 1065-6995, E-ISSN 1095-8355, Vol. 37, no 11, 1149-1156 p.Article in journal (Refereed)
    Abstract [en]

    Ambroxol, a mucokinetic anti-inflammatory drug, has been used for treatment of cystic fibrosis (CF). The respiratory epithelium is covered by the airway surface liquid (ASL), the thickness and composition of which is determined by Cl(-) efflux via the cystic fibrosis transmembrane conductance regulator (CFTR) and Na(+) influx via the epithelial Na(+) channel (ENaC). In cells expressing wt-CFTR, ambroxol increased the Cl(-) conductance, but not the bicarbonate conductance of the CFTR channels. We investigated whether treatment with ambroxol enhances chloride transport and/or CFTR and ENaC expression in CF airway epithelial cells (CFBE) cells. CFBE cells were treated with 100 µM ambroxol for 2, 4 or 8 h. mRNA expression for CFTR and ENaC subunits was analysed by real-time polymerase chain reaction (RT-PCR); protein expression was measured by Western blot. The effect of ambroxol on Cl(-) transport was measured by Cl(-) efflux measurements with a fluorescent chloride probe. Ambroxol significantly stimulated Cl(-) efflux from CFBE cells (a sixfold increase after 8 h treatment), and enhanced the expression of the mRNA of CFTR and α-ENaC, and of the CFTR protein. No significant difference was observed in β-ENaC after exposure to ambroxol, whereas mRNA expression of γ-ENaC was reduced. No significant effects of ambroxol on the ENaC subunits were observed by Western blot. Ambroxol did not significantly affect the intracellular Ca(2+) concentration. Upregulation of CFTR and enhanced Cl(-) efflux after ambroxol treatment should promote transepithelial ion and water transport, which may improve hydration of the mucus, and therefore be beneficial to CF-patients.

  • 6.
    Olsson, Joel
    et al.
    Linköping University, Department of Management and Engineering, Solid Mechanics.
    Lindholm, Jim
    Linköping University, Department of Management and Engineering, Solid Mechanics.
    Statisk hållfasthetsanalys av bärplansstag2014Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    In the course TMMT06, Mechanical engineering – project course, a mandatory project is carried out in a group, while a bachelor’s degree work is, in unison, carried out in pairs. The project, which in this case is shared by three pairs, aim to investigate the dimensioning of hydrofoils and their performance. This document is part of one of those bachelor’s degree works, and is focused on a static structural analysis of hydrofoil support struts under the influence of lift and drag forces.

    The goal with this work is to create a construction foundation to be used in the shared project. The aim of the work is to find guidelines for the selection of strut and hydrofoil assembly angles, as well as strut dimensions, depending on the size and shape of the hydrofoil.

    With the use of generally established equations for lift and drag forces, and data for hydrofoils the forces and stresses crucial to the dimensioning of the strut cross-section and assembly angles are analyzed.

    Two streamlined struts, thickness 15 mm and width 100 mm, with the hydrofoil section design Eppler 818 mounted, are studied in a static structural case without dimensioning for unexpected events, such as collisions. Within the span of velocities that are probable for a boat it was found that there never occurs any danger of buckling. Within the same span, plastic deformation does not occur either, although the stress is high enough that the safety margin is relatively small.

    The danger of buckling does not increase as the assembly angles are changed from a perpendicular position, and buckling ceases to be a factor for angles of attack lower than −4°. The stresses and the risk for plastic deformation, however, can increase as the assembly angles deviate from perpendicularity. By making the struts bigger, the construction will be able to use more demanding assembly angles, but to have anything but perpendicular struts is to be avoided. The analysis also shows that the boat should not be allowed to pitch more than 6° at high speeds to avoid large stresses in the struts.

    The largest dimensioning stress in a strut acts at the connection point with the hull or with the hydrofoil. In order to minimize the total thickness of the strut, and thus lowering the drag, it can be made thicker at the connection points while keeping it thin otherwise. The analysis also shows that an increase in strut cross-section area will give large positive outcomes in terms of safety margins against buckling and deformation.

    Eppler 818 was the only hydrofoil studied during the analysis, but the results provide good guidelines for construction of support struts in regards of strength.

  • 7.
    Andersson, Tommy
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Redesign av reduktionsutrustning i asselvalsverk inom stålindustri: Ett examensarbete utfört på konstruktionsbyrån BEKAB mot stålindustriföretaget Ovako2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The interest in seamless steel tubes with large outside diameters in relation to thin wall thickness has increased along with the strength improvements in various steel grades. This makes it possible to produce lighter, cheaper and more material-efficient steel products with the same or greater strength as before.

    These new development directions bring changes and challenges in one of the company Ovako's production lines in Tube Mill 5 Hofors, which they need to cooperate with the design agency BEKAB to evaluate and develop.

    In Ovako's production line in Tube Mill 5 there is a part of an assel mill called "förreducerare". Ovako sees a lot of interest in evaluating and developing this part of the assel mill in order to better adapt to the new development directions. A well-known challenge of the existing reduction equipment is that it was initially developed to reduce a quality issue with the tube products called funnel formation. The project therefore immerses itself into the funnel formation in order to better understand the foundations of the current design of the reduction equipment and to then implement a redesign of the reduction equipment.

    A situation analysis of the current reduction equipment reveals a number of different production issues with their accompanying quality issues in the tube products. The project thus chooses to focus on the production issues that would have the greatest impact on the reduction equipment if they were resolved. This results in a new product concept of the reduction equipment in the form of a visual 3D-CAD-model with associated strength calculations and material optimization.

    The study covers topics such as design, engineering, product development, material strength calculations and material optimization.

  • 8.
    Khajavizadeh, Lida
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Growth and structural characterization of ScN/CrN periodic and quasi-periodic superlattices for thermoelectric application2014Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    The aim of this diploma work is the deposition and characterization of ScN/CrN superlattices with both periodic and quasi-periodic structures. ScN as semiconductor material with (2eV) band gap energy was selected due to its thermal and mechanical stability and its hardness. High resistivity against oxidation and high wear resistance were the reasons for choosing CrN as another candidate for the superlattices. The Rudin Shapiro structure was selected as quasi-periodic structure because of its more random structure.

    In this research both periodic and Rudin Shapiro as quasi-periodic structures have been deposited and investigated. The best optimized temperature for the deposition was 835°C and the selected periodic thickness was 6 nm for periodic structure with each ScN and CrN layers having each a thickness of 3 nm. The material ratio of Rudin Shapiro superlattices was kept the same as periodic samples. Evaluation of quasi-periodic and periodic superlattices was performed by X-ray diffraction measurements. Five peaks were recorded for superlattices measurement of periodic structure by diffraction. The envelope of the diffraction pattern represents two separated peaks in investigation of Rudin Shapiro investigation.

    The results of the X-ay measurements showed low quality of the superlattices for both deposited structures which suggest the need for further optimization of the deposition process or the use of other materials of superlattices.

  • 9.
    Backlund, Emma
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Assessment of ventricular morphology using echocardiography in Ornate tinamous (Nothoprocta ornata) and domestic chickens (Gallus domesticus)2014Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    The Ornate Tinamou (Nothoprocta ornata), an ancient bird, has adapted to life at high altitude (>2.400 m.a.s.l) for a longer period than the domestic chicken (Gallus domesticus), which came to South America with the Spanish conquerors. Ornate tinamous have a smaller heart in relation to body size than domestic chickens. This study was made to evaluate heart morphometric measurements comparing Ornate Tinamou and domestic chicken using echocardiography measurements to determine wall thickness and chamber size and to evaluate whether it can retrieve measurements consistent with previous results on dissected hearts. I was also interested in evaluating potential adaptations of the Ornate Tinamou to life in hypoxic environments by exposing the heart to positive inotropic stimulation. The results were compared with those previously obtained on dissected hearts. The results showed that the chamber size of the domestic chicken was significantly larger than in Ornate Tinamou, both in conscious and anesthetized birds. Injection of 1µg/kg isoproterenol caused domestic chickens’ systolic chamber size to decrease significantly and fractional shortening to increase significantly. The same changes were seen in the Ornate Tinamou but they were not significant. In conclusion, this study confirms that echocardiography is a valid method for retrieving cardiac measurements without euthanizing animals, opening for the possibility of taking several measurements at different ages.

  • 10.
    Morad, Antoni
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Travancic, Faruk
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Control for Cold Rolling Mills2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report contains the details in a final research thesis work done rolling mill technology. The work is carried out at Heat Transfer located at Finspång. The main objective of this work is to evaluate thickness and flatness data from the profile to give an optimal start value for the pressure and force applied on the machine and the speed as well, so that the profiles produced, have the right thickness and best possible flatness.

    Thickness, start value for power, the degree of bending the profiles are set up and sent down to the control system.

    The report starts with a theory part describing the heating and cooling during process for aluminium profiles. A practical part describes experiments conducted on the rolling mill process under various conditions.

    The thesis work shows that the quality can be improved by rolling the slab in Aluminium industry by executing band tests and analysing graphs as 3-sigma, outward thickness and 3Dgraphs and its flatness.

  • 11.
    Wadeasa, Amal
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Charge transport in low-band gap polymers studied with the CELIV technique2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Charge transport is one of the most important properties in both organic and inorganic opto-electronic devices. Few experimental methods are typically used to measure this parameter in organic materials field, such as Time of flight method (TOF) and the recently proposed charge extraction in linear increase voltage (CELIV).

    In this project, we aim to design the experimental setup for the CELIV method in the laboratory at ITN. The thesis starts with simple definition for the conjugated polymers and materials used and then describe the theoretical part of the method to be able to extract some important parameters such as sample thickness, mobility, conductivity and electric field. The estimation of the thickness of the sample is compared with other well-established techniques as X-ray diffraction (XRD), Atomic force microscope (AFM), Ellipsometery and DekTak. Measured values of mobility and conductivity are compared to TOF results. We vary different parameters, such as polymer solution concentration, input bias, delay time, temperature and electric field. Poly (3-hexyl thiophene) or P3HT and Poly (Para-Phenylenevinylene) or PPV are the polymers characterized in this project because they have different chemical properties (side group) and physical one (regularity of the chain) and they are well-studied materials via other techniques.

  • 12.
    Nworah, Nnamdi Felix
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Fabrication and Characterization of Individually Addressable Polypyrrole Trilayer Microactuators2012Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Conjugated polymers are organic polymers that can conduct electricity. They undergo a volume change upon redox reaction and can be used as an active material in some micro- actuator system. Micro-actuators are useful in biomedical and electronic application. We have fabricated a patterned Polypyrrole (PPy) trilayer microactuator device that has individually addressable microactuators (a micro walker) which can operate in air. Furthermore, the PPy trilayer microactuator device is fabricated using standard microfabrication method called photolithography to pattern PPy on PVDF membrane material. An etching process was used to achieve the patterning process. We presented the result of characterization of speed as a function of voltage and thickness of PPy film. Secondly, distance as a function of applied voltage and thirdly, the work density as a function of applied voltage. The procedures for fabrication of PPy microactuator device, using clean room facility is detailed in this thesis.

  • 13.
    Karlsson, Marlene
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    CFRP strengthening of existing building structures2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Most of the building structures needed in twenty years from now is already built. Building structures are ageing and they deteriorate and often the demands on the structure changes over time. It is often needed to reinforce the structure, especially when reconstructing, repairing or renovating a building. The traditional strengthening methods that are used today are strengthening the structure with beams and columns of steel. The beams and columns often require much space and problems might occur if there are a lot of installations. There is another more modern technique where a composite plate, sheet, grid or bar of relatively small thickness is bonded with an epoxy adhesive to the structure. These reinforcements don’t change the cross-section of the structure. The most common type of fibre reinforcement that is used for strengthening in the building industry is carbon fibre.

    The carbon fibre products are much more expensive when comparing to steel. Therefore the object of this report is to show when it is economically motivated to use carbon fibre instead of the more traditional material steel. To do this I have studied five real cases brought to me by WSP Construction in Linköping, Sweden. The study shows that in the cases where it’s possible to use composites strengthening the building structure it is also economically motivated to do so. Even if the material is more expensive than the more traditional materials the total cost is in the same price class as the traditional ones because of the short time of construction. But there is still a problem with only a few consultants and entrepreneurs that have the knowledge and the experience to work with composites when strengthening a structure. If the knowledge will be spread to the consultants I will say that carbon fibre composites are the materials of tomorrow even in the building industry.

  • 14.
    Skårman, Karl
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Packning av lera2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The ”upper fill” is today compressed with a vibratorplate mounted on a excavator. “Anläggnings AMA” show different kinds of tools for compressing soil and thickness of the layer over the pipe to prevent it from breaking or deforming. “Anläggnings AMA” also shows how thick layers each of the equipment for compressing soil have capacity of.

    The excavator-mounted vibrator plate isn’t included in that equipment in “Anläggnings AMA”. The aim of this report is to research how different thickness of layers affects the deformation of the pipe and how the stability of the clay is affected.

    The first test was performed without any bigger problems and the results where easy to evaluate. No damage or deformation to the pipe came up with a layer thickness of 35 cm and 55 cm above the head of the pipe.

    In the other test which was much more complex then the first, were five different graves compress with different layer thickness and with different equipment. For evaluation of the compaction, a cone penetration test was used. The results from these tests were hard to evaluate though. My interpretation of the results is that a layer thickness of 45 cm gives a good compaction. Eventually you can increase the thickness but 70 cm is a little bit to much.

  • 15.
    Ekeroth, Sebastian
    Linköping University, Department of Physics, Chemistry and Biology.
    Study of protein adsorption on structured surfaces using ellipsometry2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to measure the thickness of a protein layer on a structured surface of silicon rubber, we have used ellipsometry and Fourier transform infrared (FTIR)-spectroscopy. The aim was to determine whether this type of measurement method can be used on protein layers or not. By hot-embossing a specific pattern of micrometre-sized pillars was created on the surface of the silicon rubber, which then was exposed to a phosphate buffer solution (PBS) containing human serum albumin (HSA) protein. FTIR measurements confirmed that proteins had attached to the surface. Ellipsometric studies were made and even though the protein layer was too thin to be measured, a simulation was made that revealed that a protein layer needs to be at least 1,5 nm to be measured properly with this method. We can also see that the protein molecules can get out of the solution, to find their way into the small pits of the samples.

  • 16.
    Raja, Visakha
    Linköping University, Department of Management and Engineering, Solid Mechanics.
    Sub-Modelling of a Jet Engine Component  and Creation of Stiffness Interval Based on Cast Dimensional Variations2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    While designing jet-engine components information about the loads that the component will be subjected to, is critical. For this, a full system analysis of the engine is often performed with every component put together in a large finite element model, which is called the whole engine model (WEM). This model will mostly be composed of lower order shell elements with a few thousands of elements. At the design level of a component, the FE model is detailed with several hundred thousand higher order solid elements. The detailed model cannot be directly put into the whole engine model due to excessive run times. Therefore there must be a simpler representation of the component -a sub-model- with much fewer elements so that it can be assembled into the whole engine model. This simple model must have the same stiffness (load/displacement) in chosen directions, the same mass and the basic mode shapes and frequencies should also be the same with the detailed model. 4 different structural optimisation schemes were studied to prepare a model: sizing optimisation, optimisation with material properties as design variables, combined sizing and material property optimisation and free-size optimisation. Among these free-size optimisation where each element in the model has its own design variable -thickness- was found to be the most effective method. The stiffness could be matched to the detailed model as close as 5% and so also could the first two fundamental mode shapes and frequencies. Additionally, the initial sub-model prepared was used to do a preliminary study on how variations in casting dimensions would affect the stiffness of the component in a certain direction. This was done by creating a design of experiments (DoE) for the stiffness. A response surface for the stiffness was created in terms of the dimensions that have the most significant effect. This was later used to predict an interval for the stiffness based on variations in the cast dimensions with a confidence level of 99.7%.

  • 17.
    Lai, Chung-Chuan
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics .
    Growth and Phase Stability of Titanium Aluminum Nitride Deposited by High Power Impulse Magnetron Sputtering2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    In this work, we investigate the relation between the diffusion behavior of Ti1-xAlxN at elevated temperatures and the microstructure. Thinfilm samples are synthesized by reactive co-sputtering with two cathodes. One cathode equipped with Ti target is connected to a highpower impulse magnetron sputtering (HiPIMS) power supply, and the other cathode equipped with Al target is operated with a directcurrent power source. The spinodal decomposition of cubic metastable Ti1-xAlxN controlled by thermally activated diffusion is observe fordiffusion behavior. Various HiPIMS pulsing frequencies are used to achieve different microstructure, while altered power applied to Altarget is used to change the Al content in films. In the phase composition analysis achieved by GI-XRD, the right-shift of (111) film peakalong with increasing Al-power is observed. A saturation of the right-shift and h-AlN peaks are also observed at certain Al-power. Thechemical composition determined by ERDA shows trends of reducing Al solubility limit in metastable phase and O contamination upondecreasing the pulsing frequency. More N deficiency is found in samples deposited with higher frequency. In the 500 Hz and 250 Hzsamples deposited into similar composition and thickness, no apparent difference of the microstructure is observed from the SEM crosssectionalimages. From HT-XRD, we observe higher intensity of TiO2 and h-AlN peaks in 500 Hz sample at elevated temperature ascompared with 250 Hz one. From the reduction of O contamination, denser Ti1-xAlxN films are able to be deposited with lower HiPIMSpulsing frequency. In addition, the higher intensity observed in HT-XRD patterns indicates that the 500 Hz sample is more open todiffusion and therefore allows the new formed phases to grow in larger grains.

  • 18.
    Chang, Yan
    Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Impacts of Climate Changeson Reservoirs in Northern Sweden: case study of Akkajaure reservoir by modelling2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Since the middle of the 20th century, the average temperature of the atmosphere near Earthsurface has increased. The global warming causes many effects in hydrological systems, suchas changes in thermal structure, water quality, aquatic ecosystems, etc. This thesis studies theimpact of climate change on Akkajaure reservoir, the second largest regulated reservoir inSweden, by simulating a predicted temperature rise based on the climate and hydrologicalconditions of Akkajaure in 1998-2002. The congeal duration, ice thickness and the turbulentkinetic energy (TKE) in the lake were calculated by the catchment hydrological model and thelake model. The movement of phytoplankton and their mean net production (MeanNP) rateare simulated by the dispersion model and the photosynthesis model. By comparing thesimulation results of past situation and three predicted scenarios, it is obtained that theincreases of temperature shorten the congeal duration, which is a lead factor for shortening thetrough period and amplification of peak value of TKE. The comparison of plankton particlesposition illustrates that the particles stay in a deeper position for a longer time because of thechanges of TKE. Though the plankton stays in euphotic zone longer as the temperatureincreases, the comparison of the mean production rate between the real scenario and thepredicted scenarios concludes that the mean production rate grows as the temperatureincreases because the shortened ice cover period makes the duration of absorbed sunlightincreases in lake. The effects of global warming may influence the distribution of microalgaein on high latitude lakes and reservoirs. The phytoplankton will stay in deeper water layers fora longer time.

  • 19.
    Larsson, Emanuel
    Linköping University, Department of Physics, Chemistry and Biology, Biotechnology .
    Quantitative Analysis of Bone Tissue Engineering Scaffolds and Skull Bones by means of Synchrotron and Conventional X-ray Computed Microtomography2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The study of internal structure of materials has always been an essential issue in a variety of application fields, from the medical radiology to the materials science. X-ray computed microtomography (with both conventional and synchrotron radiation sources) has a great potential for these purposes because its three-dimensional and non destructive nature as well as the fact that it does not require any sample preparation and it allows to study samples under stress or after consecutive treatments.

    The recent developments of new X-ray sources with innovative imaging techniques, as well as novel high resolution detectors, allow moving forward the maximum achievable resolution of this technique to a few micrometers or even less. This contributed to increase its application in biomedical purposes, but also to raise the need for quantitative analysis of the reconstructed data.

    Indeed in most of the cases a quantitative characterization of the samples microstructures is needed to better understand their physical and chemical behavior, the effects of manufacturing process or the response to stress. Dedicated software packages have been developed to perform a geometrical and morphological characterization of the samples texture and to evaluate some typical parameters commonly used to classify porous media such as porosity, cell size distribution, connectivity and anisotropy.

    In this work two case studies have been considered for the application of a quantitative analysis approach to microtomography datasets: the first concerns the characterization of bone ingrowth within tissue engineering scaffolds, while the second is related to the extraction of morphological descriptors for the architecture of human skull bones.

    It will be shown how suitable image processing and analysis techniques are able to effectively quantify significant parameters such as the trabecular thickness of the skull bones as well as the porosity and the degree of connectivity of bone tissue engineering scaffolds. Similar quantitative analysis methods applied to microtomography images have to be considered as an effective methodology for a comprehensive characterization of other biomedical samples.

  • 20.
    Faghani, Farshad
    Linköping University, Department of Science and Technology, Physics and Electronics.
    Thermal conductivity Measurement of PEDOT:PSS by 3-omega Technique2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Conducting polymers (CP) have received great attention in both academic and industrial areas in recent years. They exhibit unique characteristics (electrical conductivity, solution processability, light weight and flexibility) which make them promising candidates for being used in many electronic applications. Recently, there is a renewed interest to consider those materials for thermoelectric generators that is for energy harvesting purposes. Therefore, it is of great importance to have in depth understanding of their thermal and electrical characteristics. In this diploma work, the thermal conductivity of PEDOT:PSS is investigated by applying 3-omega technique which is accounted for a transient method of measuring thermal conductivity and specific heat.

    To validate the measurement setup, two benchmark substrates with known properties are explored and the results for thermal conductivity are nicely in agreement with their actual values with a reasonable error percentage. All measurements are carried out inside a Cryogenic probe station with vacuum condition. Then a bulk scale of PEDOT:PSS with sufficient thickness is made and investigated. Although, it is a great challenge to make a thick layer of this polymer since it needs to be both solid state and has as smooth surface as possible for further gold deposition.

    The results display a thermal conductivity range between 0.20 and 0.25 (W.m-1.K-1) at room temperature which is a nice approximation of what has been reported so far. The discrepancy is mainly due to some uncertainty about the exact value of temperature coefficient of resistance (TCR) of the heater and also heat losses especially in case of heaters with larger surface area. Moreover, thermal conductivity of PEDOT:PSS is studied over a wide temperature band ranging from 223 - 373 K.

  • 21.
    Kedsongpanya, Sit
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University.
    Nanolaminated Thin Films for Thermoelectrics2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Energy harvesting is an interesting topic for today since we face running out of energy source, a serious problem in the world. Thermoelectric devices are a good candidate. They can convert heat (i.e. temperature gradient) to electricity. This result leads us to use them to harvest waste heat from engines or in power plants to generate electricity. Moreover, thermoelectric devices also perform cooling by applied voltage to device. This process is clean, which means that no greenhouse gases are emitted during the process. However, the converting efficiency of thermoelectrics are very low compare to a home refrigerator. The thermoelectric figure of merit (ZTm) is a number which defines the converting efficiency of thermoelectric materials and devices. ZTm is defined by Seebeck coefficient, electrical conductivity and thermal conductivity. To improve the converting efficiency, nanolaminated materials are good candidate.

     

    This thesis studies TiN/ScN artificial nanolaminates, or superlattices were grown by reactive dc magnetron sputtering from Ti and Sc targets. For TiN/ScN superlattice, X-ray diffraction (XRD) and reciprocal space map (RSM) show that we can obtain single crystal TiN/ScN superlattice. X-ray reflectivity (XRR) shows the superlattice films have a rough surface, supported by transmission electron microscopy (TEM). Also, TiN/ScN superlattices grew by TiN as starting layer has better crystalline quality than ScN as starting layer. The electrical measurement shows that our superlattice films are conductive films.

     

    Ca-Co-O system for inherently nanolaminated materials were grown by reactive rf magnetron sputtering from Ca/Co alloy target. The XRD shows we maybe get the [Ca2CoO3]xCoO2 phase, so far. The energy dispersive X-ray spectroscopy (EDX) reported that our films have Al conmination. We also discovered unexpected behavior when the film grown at high temperature showed larger thickness instead of thinner, which would have been expected due to possible Ca evaporation. The Ca-Co-O system requires further studies.

  • 22.
    Lin, Yuan-Chih
    Linköping University. Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    SiC Homoepitaxial Growth at High Rate by Chloride-based CVD2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    SiC is an attractive material since it has remarkable properties. For several years efforts have been put primarily in electronic applications. High power and high frequency devices can be fabricated on SiC due to its wide band gap, high breakdown field and high thermal conductivity. SiC devices can be used in harsh environment since its operation temperature is significantly high (about 1200 ). SiC bulk growth has been improved by seeded physical vapour transport (PVT) during last decades. However, the quality and doping concentration of SiC bulk are not good enough to be used as an active layer for devices. SiC epilayer growth by chemical vapour deposition (CVD) was established in the last three decades. Only about 5 µm/h growth rate is achieved by CVD with a standard process. Long deposition time is required to grow ≥100µm thick epilayer for high voltage devices. The main problem in standard CVD is the formation of silicon (Si) droplets due to supersaturation of Si-species on the growth surface or in the gas-phase, which is detrimental for devices performance. To solve the problem of Si-droplets, chloride-based CVD was introduced. Chlorinated species can dissolve the silicon aggregates through the formation of strong bonds to silicon species compared to Si-Si bonds. Typical chlorinated precursors are hydrogen chloride (HCl) and methyltrichlorosilane (MTS). In this thesis study, HCl was mainly used as chlorinated precursors. Distinct chlorinated precursors result in different chemical reactions which affect the epilayer growth appreciably. The Cl/Si ratio, which is the ratio of the amount of chlorinated precursors to silicon precursors, is a very critical growth parameter for morphology, growth rate and background doping concentration. The C/Si ratio and Si/H2 ratio also affect the epilayer growth appreciably. Besides, growth temperature, growth pressure and temperature ramp up condition are other important growth parameters. In the CVD reaction chamber, the temperature profile and gas species distribution are not uniform along the whole susceptor length, which leads to different thickness of epilayer, morphology and doping concentration at different area of the reaction chamber. The polarity and off-angle of substrates can bring about complete different grown epilayers. Epitaxial defects are mainly replicated from the substrate. Therefore, the quality of substrates is very important as well. Deep energy levels can be introduced by adding transition metal such as vanadium (V), chromium (Cr) or tungsten (W). There are some limits which are needed to be overcome for a complete development of SiC. 4” SiC wafers are commercially available on the market, larger diameter would be very useful for the industrial development of SiC. High growth rate and good quality with controlled uniformity are desired for electronic applications. In this thesis, the influences of growth parameters such as C/Si and Cl/Si ratios, comparison between different precursors, growth condition in different areas of reaction chamber and effects of substrate polarity are discussed. Intentional incorporation of tungsten atoms is investigated by deep-level transient spectroscopy measurement and thermodynamic analysis.

  • 23.
    Tseng, Wei-Min
    Linköping University, Department of Science and Technology.
    Investigation of vertical organic transistor geometries and materials for printable applications2010Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The  discovery  of  organic  electronics  has  opened  many  new  possibilities  for electronic industries and systems. For organic field effect transistors (OFETs), many advantages,  such  as  high  flexibility,  low-cost  production  and  large  area  processing, can be used in many applications. Even though OFET cannot replace the conventional FET to lead the electronic industries, there are still many possibilities of OFET that conventional FET cannot approach.  In transistor development, scaling down the devices has been the main challenge for  a  long  time.  By  scaling  down  the  size,  transistors  become  faster,  smaller,  less power  consumption,  and  are  cheaper  for  fabrication.  Shortening  the  channel  of transistors is a main problem in reducing the device size. To address this, processing of a vertically structured OFET is a much easier way of shortening the channel length compared to using the ordinary lateral channel structure of OFET.    In this thesis, two methods were used for processing vertically  separated drain and  source  electrodes:  one  is  the  dry-etching  method,  and  the  other  one  is  the oblique-incidence depositing method. Au as conducting material of drain and source electrodes,  P3HT  as  semiconductor,  PSSH  as  electrolyte,  and  the  Ti/probe  of  FET station  as  gate  material  were  chosen  for  the  experiments.  For  insulating  material,  a polyvinylidene  fluoride  copolymer  was  used  in  dry-etching  method  and  SU-8 photoresist was used in oblique-incidence depositing method. The channel length in this thesis depended on the thickness of the insulating layer. A channel of around 10 µm was processed using the dry-etching method with a yield of almost 95 percent and a  channel  smaller  than  1  µm  was  processed  using  the  oblique-incidence  depositing method with a yield of around 80 percent.

  • 24.
    Tang, Zheng
    Linköping University, Department of Physics, Chemistry and Biology.
    Studies of Inverted Organic Solar Cells Fabricated by Doctor Blading Technique2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Over the last few decades, bulk-heterojunction organic photovoltaic devices comprising an intimately mixed donor-acceptor blend have gained serious attention due to their potential for being cheap, light weight, flexible and environmentally friendly. In this thesis, APFO-3/PCBM bulk-heterojunction based organic photovoltaic devices with an inverted layer sequence were investigated systematically. Doctor blade coating is a technique that is roll-to-roll compatible and cost efficient and has been used to fabricate the solar cells.

    Initial studies focused on optimization of the electrodes. A thin film of the conductive polymer PEDOT:PSS was chosen to be the transparent anode. Different PEDOT:PSS films with respect to the film thickness and deposition temperature were characterized in terms of conductivity and transmission. Decent conductance and transmittance were obtained in the films deposited with wet film thickness setting of 35 μm, The cathode was fabricated from a metal bilayer comprising Al and Ti with an area about 1 cm2, and the best-working cathodes contained a 70 nm thick Al layer covered by a thin Ti layer of about 10 -15 nm.

    Optimized coating temperature and wet film thickness settings for the active layer and PEDOT:PSS layer were experimentally determined. The highest efficiency of the APFO-3/PCBM based inverted solar cells fabricated by doctor blading was 0.69%, which exceeded the efficiency of spin-coated inverted cells.

    A higher efficiency (0.8 %) was achieved by adding a small amount of high molecular weight polystyrene to the active layer. Morphological changes after adding of the polystyrene were observed by optical microscopy and AFM. A coating temperature dependent phase separation of the APFO-3/PCBM/polystyrene blend was found.

     

  • 25.
    Qiu, Li
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Polygonal models from range scanned trees2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    3D Models of botanical trees are very important in video games, simulation, virtual reality, digital city modeling and other fields of computer graphics. However, since the early days of computer graphics, the modeling of trees has been challenging, because of the huge dynamical range between its smallest and largest structures and their geometrical complexity. Trees are also ubiquitous which makes it even hard to model them in a realistic way, Current techniques are limited in that they model a tree either in a rule-based way or in an approximated way. These methods emphasize appearance while sacrificing its real structure. Recent development in range scanners are making 3D aquisition feasible for large and complex objects. This report presents the semi-automatic technique developed for modeling laser-scanned trees. First, the user draws a few strokes on the depth image plane generated from the dataset. Branches are then extracted through the 2D Curve detection algorithm originally developed. Afterwards, those short branches are connected together to generate the skeleton of the tree by forming a Minimum Spanning Tree (MST). Finally, the geometry of the tree skeleton is produced using allometric rules for branch thickness and branching angles.

  • 26.
    van den Bos, B
    et al.
    CSM Mat Teknik, S-58113 Linkoping, Sweden.
    Sahlen, S
    CSM Mat Teknik, S-58113 Linkoping, Sweden.
    Andersson, J
    Automatic scanning with multi-frequency eddy current on multilayered structures2001In: Insight (Northampton), ISSN 1354-2575, Vol. 43, no 3, 163-166 p.Article in journal (Refereed)
    Abstract [en]

    Eddy current testing is a frequently used NDT method at Saab/CSm but until recently only single frequency testing has bern used. Through the participation of Saab/CSM in a Brite-Euram project, 'CANDIA', it has been possible for Its to learn about multi-frequency testing and also to combine it with a flexible scanner developed in a preceding Brite-Euram project. The purpose of our work was to increase both testing speed and sensitivity ht: using multi-frequency eddy current testing, combined with a scanning system for corrosion detection in multi-layered structures. The wing of the Saab 2000 aircraft was one specific example for which several samples were manufactured with both artificial (chemically etched) corrosion of various severity and cracks. After optimising single frequencies, multi-frequency testing was adopted Using the previously determined optimal single frequency as a start, frequency combinations were determined to give increased detectability for the different structures and defects. The influence of different disturbing signals, for example signals from rivets, thickness variations, noise, and how to reduce them using the multi-frequency technique, was studied. A scanner was adapted to make it compatible with the eddy current instrument, resulting in a complete scanning system. During the project, tests were also made in 'field' conditions to evaluate the system. Components with real corrosion have also been tested with promising results. The possibility to produce scans from the mixed multi-frequency signals was very fruitful. The goals to increase testing speed and sensitivity have been reached. The combination of an advanced multi-frequency instrument with a scanning system will result in faster inspections and yield better results than could be achieved previously at Saab and CSM. These developments will increase the use of eddy current inspections.

  • 27.
    Avdic, Nermin
    Linköping University, Department of Management and Engineering, Assembly technology .
    Automatisering av flexibel fixtur2009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis was conducted at Linköping University and SAAB Aerostructures, Linköping, and focuses on the automation of flexible fixturing in machining applications. At Linköping University a project called "Koofix" is conducted with support from Strategiska stiftelsen and several manufacturing industries including SAAB Aerostructures. The purpose of this project is to develop a more cost-effective, flexible, technique for fixation of workpieces during processing and assembly.

    Fixtures are an important part during the machining process, especially if you process the parts with high accuracy. Today a large number of fixtures are used at SAAB and they would prefer to reduce the number of fixtures by using flexible fixtures instead. SAAB uses one fixture for each article and this result in a high fixture cost and it also takes time to design and construct a new fixture.

    There are several advantages with using a flexible fixture such as that you can process workpieces with different length, height and thickness in the same fixture. Bigger workpieces takes time to fasten in the fixture because the machine operator must tighten the clamps by hand. By automating the fixture with for example grippers or clamping cylinders the set time would be reduced because the clamping process is automatic.

    In this report there is also a mapping of various flexible fixture components such as grippers, clamping cylinders and linear units. These components are quite common today in the processing industry and are also used in fixtures. The idea of flexible components is to provide a more flexible and automated fixture then the currently used at SAAB. These components were also linked to a concept idea and based on this idea, several concepts were sketched. The result of the concept idea was two concepts that were generated in the CAD program CATIA.

    The first concept uses grippers for the clamping process and for additional flexibility the grippers can also be rotated with rotary actuators. Linear units are used to automatically position the beams to reduce the set time. The second concept uses clamping cylinders and rotary grippers to clamp the workpiece. Beams are positioned by an operator, but linear units could also be used in this concept as well.

    Finally, the concepts were evaluated according to a method from Ullman with a so called decision matrix. The concept that fulfilled the criteria best was concept 1, which uses grippers and linear units. Another method that was used from Ullman was a QFD (Quality Function Deployment) chart and this chart shows the design requirements that are important and that should be fulfilled.

    The components that are presented in this report have not been tested. This could be a suggestion in an upcoming work to test these components. For example the pneumatic linear units with passive or active brake could be tested to make sure that the braking force is sufficient.

  • 28.
    Rung, A
    et al.
    Uppsala Univ, Div Solid State Phys, Angstrom Lab, SE-75121 Uppsala, Sweden Swedish Dewf Res Agcy, Dept Funct Mat, SE-58111 Linkoping, Sweden.
    Ribbing, CG
    Uppsala Univ, Div Solid State Phys, Angstrom Lab, SE-75121 Uppsala, Sweden Swedish Dewf Res Agcy, Dept Funct Mat, SE-58111 Linkoping, Sweden.
    Calculated photonic structures for infrared emittance control2002In: Applied Optics, ISSN 0003-6935, Vol. 41, no 16, 3327-3331 p.Article in journal (Refereed)
    Abstract [en]

    Using an available program package based on the transfer-matrix method, we calculated the photonic band structure for two different structures: a quasi-three-dimensional crystal of square air rods in a high-index matrix and an opal structure of high-index spheres in a matrix of low index, epsilon = 1.5. The high index used is representative of gallium arsenide in the thermal infrared range. The geometric parameters of the rod dimension, sphere radius, and lattice constants were chosen to give total reflectance for normal incidence, i.e., minimum thermal emittance, in either one of the two infrared atmospheric windows. For these four photonic crystals, the bulk reflectance spectra and the wavelength-averaged thermal emittance as a function of crystal thickness were calculated. The results reveal that potentially useful thermal signature suppression is obtained for crystals as thin as 20-50 mum, i.e., comparable with that of a paint layer. (C) 2002 Optical Society of America.

  • 29.
    Papachristos, V.D.
    et al.
    Laboratory of Physical Metallurgy, Natl. Tech. Univ. Athens, 157 80 Z., Athens, Greece.
    Panagopoulos, C.N.
    Laboratory of Physical Metallurgy, Natl. Tech. Univ. Athens, 157 80 Z., Athens, Greece.
    Wahlstrom, U.
    Industrial Microelectronics Center, 581 83, Linkoping, Sweden.
    Christoffersen, L.W.
    Technical University of Denmark, 2800, Lyngby, Denmark.
    Leisner, P.
    Industrial Microelectronics Center, 581 83, Linkoping, Sweden.
    Effect of annealing on the structure and hardness of Ni-P-W multilayered alloy coatings produced by pulse plating2000In: Materials Science & Engineering: A, ISSN 0921-5093, Vol. 279, no 1-2, 217-230 p.Article in journal (Refereed)
    Abstract [en]

    Ni-P-W multilayered alloy coatings were deposited on copper foils by pulse plating, using a rotating cylinder electrode. They consisted of layers of high (Ni-5 wt.% P-45 wt.% W) and low (Ni-8 wt.% P-15 wt.% W) W content. The wavelengths studied were 8, 40 and 400 nm and the total thickness of the coatings was approximately 25 µm. The multilayered coatings were annealed in the temperature range between 200 and 800°C and the effect of annealing on their structure was studied by using X-ray diffraction, cross-sectional transmission electron microscopy equipped with selected area electron diffraction facility, and differential thermal analysis. The initially amorphous multilayered coatings crystallise in steps as the annealing temperature increases (first the low-W crystallise layers and then the high-W layers), and the layered structure is lost around 600°C. The main crystalline phases formed during annealing are Ni-W solid solution and Ni3P. The wavelength of the coatings seems to affect the onset temperature of the crystallisation processes. The hardness of the coatings initially increases reaching a maximum in the 500-600°C range, and then decreases as the annealing temperature increases. (C) 2000 Elsevier Science S.A. All rights reserved.Ni-P-W multilayered alloy coatings were deposited on copper foils by pulse plating, using a rotating cylinder electrode. They consisted of layers of high (Ni-5 wt.% P-45 wt.% W) and low (Ni-8 wt.% P-15 wt.% W) W content. The wavelengths studied were 8, 40 and 400 nm and the total thickness of the coatings was approximately 25 µm. The multilayered coatings were annealed in the temperature range between 200 and 800°C and the effect of annealing on their structure was studied by using X-ray diffraction, cross-sectional transmission electron microscopy equipped with selected area electron diffraction facility, and differential thermal analysis. The initially amorphous multilayered coatings crystallise in steps as the annealing temperature increases (first the low-W crystallise layers and then the high-W layers), and the layered structure is lost around 600°C. The main crystalline phases formed during annealing are Ni-W solid solution and Ni3P. The wavelength of the coatings seems to affect the onset temperature of the crystallisation processes. The hardness of the coatings initially increases reaching a maximum in the 500-600°C range, and then decreases as the annealing temperature increases.

  • 30.
    Filippini, D.
    et al.
    Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
    Weiss, T.
    Weiß, T., Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
    Aragon, R.
    Aragón, R., Laboratorio de Películas Delgadas, Facultad de Ingeniería, Universidad de Buenos Aires and Prinso-Conicet-Citefa, Paseo Colón 850 (1063), Capital Federal, Argentina.
    Weimar, U.
    Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, Division of Applied Physics, Department of Physics and Measurement Technology, Linkoping University, SE-581 83 Linkoping, Sweden.
    New NO2 sensor based on Au gate field effect devices2001In: Sensors and actuators. B, Chemical, ISSN 0925-4005, Vol. 78, no 1-3, 195-201 p.Article in journal (Refereed)
    Abstract [en]

    A new NO2 field effect gas sensor based on Au gates is demonstrated and the influence of gate morphology on sensor response is evaluated. A sensitization mechanism, for non-catalytic continuous gates, based on grain boundary diffusion is proposed. The sensors are fabricated as MOS (metal-oxide-semiconductor) capacitors with sputtered or thermal evaporated Au gates (at different substrate temperatures) with thickness between 75 and 960 nm. The devices' sensitivity, in the range of 15-200 ppm of NO2 in dry air, depends strongly on gate morphology, shorter response times and larger voltage shifts are correlated with smaller grain sizes. Scanning-electron-microscope (SEM) images show that the microstructure is very stable after 5 months of gas exposure at temperatures up to 200°C. The sensors are selective to NO2 (with NO, H2 and CO as interfering gases) and selectivity depends also on gate structure. © 2001 Elsevier Science B.V. All rights reserved.

  • 31.
    Podskochy, A.
    et al.
    St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
    Fagerholm, P.
    St. Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
    The expression of fas ligand protein in ultraviolet-exposed rabbit corneas2002In: Cornea, ISSN 0277-3740, E-ISSN 1536-4798, Vol. 21, no 1, 91-94 p.Article in journal (Refereed)
    Abstract [en]

    Purpose. Keratocytes undergo apoptosis during various pathologic conditions and after exposure to ultraviolet radiation (UVR). It was reported that the Fas/Fas ligand system is involved in modulating keratocyte apoptosis. The expression of Fas ligand (FasL) protein was studied in rabbit corneas after photokeratitis induced by different UV wavelengths. Methods. Six New Zealand albino rabbit corneas were exposed to 280- and 310-nm UVR in 10-nm full wavebands at doses producing biomicroscopically significant keratitis (0.12 J/cm2 for 280 nm and 0.47 J/cm2 for 310 nm). Animals were killed 24 hours after exposure. Immunohistochemistry was performed to localize FasL protein in paraffin sections of rabbit corneas. Primary antibody was polyclonal goat anti-FasL IgG. Results. FasL protein was uniformly detected in epithelial and endothelial layers of all UVR-exposed and control, nonexposed corneas. The positive staining of keratocytes was confined to the anterior stroma of corneas that were exposed to 280-nm UVR. Corneas exposed to 310-nm UVR showed positively stained keratocytes throughout the entire thickness of the stroma. Conclusions. These data strongly suggest that the Fas/FasL system may play an important role in apoptosis of corneal cells after UVR. The FasL expression in the corneal stroma was more extensive after exposures at 310-nm UVR than at 280-nm UVR.

  • 32. Schifano, R.
    et al.
    Vinattieri, A.
    Department of Physics, University of Florence, Via Sansone 1, I-50019 Sesto Fiorentino, Italy.
    Bruzzi, M.
    Department of Energetics, Istituto Nazionale di Física Nucleare (INFN), University of Florence, Via di Santa Marta 3, I-50139 Florence, Italy.
    Miglio, S.
    Department of Energetics, Istituto Nazionale di Física Nucleare (INFN), University of Florence, Via di Santa Marta 3, I-50139 Florence, Italy.
    Lagomarsino, S.
    Department of Energetics, Istituto Nazionale di Física Nucleare (INFN), University of Florence, Via di Santa Marta 3, I-50139 Florence, Italy.
    Sciortino, S.
    Department of Energetics, Istituto Nazionale di Física Nucleare (INFN), University of Florence, Via di Santa Marta 3, I-50139 Florence, Italy.
    Nava, F.
    Department of Physics, University of Modena, Via Campi 213A, I-41100 Modena, Italy.
    Electrical and optical characterization of 4H-SiC diodes for particle detection2005In: Journal of Applied Physics, ISSN 0021-8979, Vol. 97, no 10, 103539- p.Article in journal (Refereed)
    Abstract [en]

    The electronic and optical properties of several (medium to high quality) 4H-SiC epitaxial sensors for particle detection have been studied. The samples are n -doped Schottky diodes with different nitrogen concentrations (6× 1013 cm-3 -5× 1015 cm-3) and thicknesses (20-40 µm). A full electrical and optical characterization has been performed by capacitance versus voltage measurements and near-band-edge low-temperature photoluminescence. The effective doping along the epilayer and the depletion width have been determined and data are consistent with the charge collection efficiency characterization performed with a minimum ionizing ? -source. All the investigated samples exhibit a 100% collection efficiency. In particular, the best samples yield a highly reproducible signal, well separated from the pedestal. Photoluminescence results show a linear relationship between the effective doping and the ratio of nitrogen-bound excitonic emission (Q0) and free excitonic line (I76), in agreement with a previous work on 4H-SiC with a higher doping concentration [I. G. Ivanov, C. Hallin, A. Henry, O. Kordina, and E. Janzn, J. Appl. Phys. 80, 3504 (1996)]. Moreover we show that the dependence of the major spectral features as a function of the penetration depth of the exciting laser beam can quantitatively provide information on substrate contribution to the photoluminescence. In conclusion, we bring evidence that a detailed characterization of SiC-based detectors, by all optical techniques, yields an accurate value for the net doping and gives a qualitative information on the epilayer thickness prior to any electrical wafer tests. © 2005 American Institute of Physics.

  • 33.
    Wright, D
    et al.
    IFM Linköpings universitet.
    Kerje, S
    Dept of Medical Science Uppsala University.
    Lundström, K.
    Dep of Food Science Swedish University of Agricultural Science.
    Babol, J.
    Dep of Food Science Swedish University of Agriculture Science, Uppsala.
    Schultz, K.
    Dep of Animal Environment and Health Swedish University of Agricultural Sciences, Uppsala.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    Andersson, L.
    Dep of Animal Breeding and Genetics Swedish University of Agricultural Sciences, Uppsala.
    Quantitative trait loci analysis of egg and meat production traits in a red junglefowl · White Leghorn cross2006In: Animal Genetics, ISSN 0268-9146, E-ISSN 1365-2052, Vol. 37, no 6, 529-534 p.Article in journal (Refereed)
    Abstract [en]

    Egg and production traits are of considerable economic importance in chickens. Using a White Leghorn × red junglefowl F2 intercross, standard production measures of liver weight and colour, egg size, eggshell thickness, egg taste and meat quality were taken. A total of 160 markers covering 29 autosomes and the Z chromosome were genotyped on 175–243 individuals, depending on the trait under consideration. A total of nine significant quantitative trait loci (QTL) and three suggestive QTL were found on chicken chromosomes 1, 2, 4, 5, 7, 8, 10, 12, E47W24 and E22C19W28.

  • 34.
    Båvall, Lennart
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Determination of thickness of silver coatings on brass by measuring the impedance of a thin elliptic coil2007In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, Vol. 56, no 3, 790-799 p.Article in journal (Refereed)
    Abstract [en]

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

  • 35.
    Persson, Nils-Krister
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, Xiangjun
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Optical limitations in thin-film low-band-gap polymer/fullerene bulk heterojunction devices2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 8, 083503- p.Article in journal (Refereed)
    Abstract [en]

    Photovoltaic devices from the low-band-gap alternating copolymer APFO-Green1, blended with the fullerene derivative BTPF70 as electron acceptor, show a pronounced variation of the external quantum efficiency with varying thickness. Device simulation, based on ellipsometric characterization, reveals that this behavior is to be expected and valid also for most low-band-gap polymers and that it can be explained by optical interference. Requirements for materials suitable for wide spectral coverage in thin-film organic solar cells are delineated. Furthermore, the internal quantum efficiency is calculated to be ≈ 0.4.

  • 36. Gustafson, Carl-Johan
    et al.
    Birgisson, Agust
    Junker, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Plastic Surgery, Hand Surgery and Burns.
    Huss, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of surgery. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Salemark, Lars
    Johnson, Hans
    Kratz, Gunnar
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of surgery. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Employing human keratinocytes cultured on macroporous gelatin spheres to treat full thickness-wounds: An in vivo study on athymic rats2007In: Burns, ISSN 0305-4179, Vol. 33, no 6, 726-735 p.Article in journal (Refereed)
    Abstract [en]

    Providing cutaneous wounds with sufficient epidermis to prevent infections and fluid loss is one of the most challenging tasks associated with surgical treatment of burns. Recently, application of cultured keratinocytes in this context has allowed this challenge to be met without several of the limitations connected with the use of split-thickness skin grafts. The continuous development of this novel approach has now revealed that transplantation of cultured autologous keratinocytes as single-cell suspensions exhibits several advantages over the use of cultured epidermal grafts. However, a number of methodological problems remain to be solved, primarily with regards to the complexity of culturing these cells, loss of viability and other negative effects during their preparation and transportation, the relatively long period of time required following transplantation to obtain a sufficiently protective epidermis. In the present investigation we attempted to eliminate these limitations by culturing the keratinocytes on macroporous gelatin spheres. Accordingly, the efficacies of normal human keratinocytes in single-cell suspension or growing on macroporous gelatin spheres, as well as of split-thickness skin grafts in healing wounds on athymic rats were compared. Human keratinocytes were found to adhere and proliferate efficiently both on the surface and within the pores of such spheres. Transplantation of such cells adherent to the spheres resulted in significantly more rapid formation of a stratified epidermis than did transplantation of single-cell suspensions or spheres alone. Twenty-three days after transplantation, the epidermis formed from the cells bound to the spheres was not as thick as the epidermis on wounds covered with split-thickness skin grafts, but significantly thicker than on wounds to which single-cell suspensions, spheres alone or no transplant at all was applied. Furthermore, fluorescence in situ hybridisation revealed that the transplanted keratinocytes, both those adherent to gelatin spheres and those in single-cell suspension, were components of the newly formed epidermis. These findings indicate that application of biodegradable macroporous spheres may prove to be of considerable value in designing cell-based therapies for the treatment of acute and persistent wounds. © 2006 Elsevier Ltd and ISBI.

  • 37.
    Zhang, Fengling
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Ceder, M.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Enhancing the photovoltage of polymer solar cells by using a modified cathode2007In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 19, no 14, 1835-1838 p.Article in journal (Refereed)
    Abstract [en]

    A method to increase the open-circuit voltage (Voc) up to 200 mV and the power conversion efficiency (PCE) by 50%, by using a thin layer of poly(ethylene oxide) (PEO) to modify the cathode in polymer solar cells, was reported. An enhanced photocurrent of polymer solar cells by bending a small amount of PEO and LiCF3SO3 into the active layer was also demonstrated. The results show that the value of open-circuit voltage increases in all diodes with PEO by 150 to 200 mV while the fill factor (FF) increases with a decrease of the thickness of PEO. The thickness of the PEO layers on Si wafers measured by using ellipsometry shows that the thickness are 3.8 nm for 1000 rmp, 2.1 nm for 3000 rmp, and 1.4 nm for 5000 rmp. The quantitative similarity of the J-V characteristics in the dark between the diodes containing PEO and LiF shows that PEO has an analogous function in the device as LiF.

  • 38.
    Lebedev, Alexander
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Zelenin, V.V.
    Abramov, P.L.
    Bogdanova, E.V.
    Lebedev, S.P.
    Nel¿son, D.K.
    Razbirin, B.S.
    Shcheglov, M.P.
    Tregubova, A.S.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    A study of thick 3C-SiC epitaxial layers grown on 6H-SiC substrates by sublimation epitaxy in vacuum2007In: Semiconductors (Woodbury, N.Y.), ISSN 1063-7826, Vol. 41, no 3, 263-265 p.Article in journal (Refereed)
    Abstract [en]

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

  • 39.
    Lattemann, Martina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics .
    Ulrich, S.
    Forschungszentrum Karlsruhe.
    Investigation of structure and mechanical properties of magnetron sputtered monolayer and multilayer coatings in the ternary system Si-B-C2007In: Surface & Coatings Technology, ISSN 0257-8972, Vol. 201, no 9-11 SPEC. ISS., 5564-5569 p.Article in journal (Refereed)
    Abstract [en]

    In the present work SiC and B4C monolayers as well as SiC/B4C multilayer coatings have been investigated with respect to their composition and mechanical properties. The coatings have been deposited on silicon substrates and polished cemented carbide inserts by non-reactive dual radio frequency (r.f.) magnetron sputtering from stoichiometric, high-purity silicon carbide (99.5%) and boron carbide (99.9%) targets. Amorphous stoichiometric SiC and B4C have been achieved with high hardness of 2950 HV0.01 and 4160 HV0.01 with a residual stress of - 3.4 GPa and - 2.9 GPa, respectively. The number of monolayers in the multilayer system with a constant total layer thickness has been varied in order to investigate the influence of the number of interfaces on film composition and properties. Additionally, the monolayer thickness ratio for a constant modulation period (double layer thickness) was varied. In this multilayer system no notable hardness enhancement could be observed. Despite the absence of the hardness enhancement, the toughness is expected to be enhanced due to stress relaxation and a reduction of crack propagation by crack dissipation along the interfaces. An abrupt interface is considered to be an indispensable requirement. However, the strain fields and the difference of the mechanical properties in the interfacial region are also of importance. © 2006 Elsevier B.V. All rights reserved.

  • 40.
    Zhou, Ye
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Gorochovceva, Natalija
    Polymer chemistry Vilnius University.
    Makuska, Ricardas
    Polymer Chemistry Vilnius University.
    Dedinaite, Andra
    Surface Chemistry KTH.
    Claesson, Per M.
    Surface Chemistry KTH.
    Chitosan-N-poly(ethylene oxide) brush polymers for reduced nonspecific protein adsorption2007In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 305, no 1, 62-71 p.Article in journal (Refereed)
    Abstract [en]

    The possibility of using a novel comb polymer consisting of a chitosan backbone with grafted 44 units long poly(ethylene oxide) side chains for reducing nonspecific protein adsorption to gold surfaces functionalized by COOH-terminated thiols has been explored. The comb polymer was attached to the surface in three different ways: by solution adsorption, covalent coupling, and microcontact printing. The protein repellant properties were tested by monitoring the adsorption of bovine serum albumin and fibrinogen employing surface plasmon resonance and imaging null ellipsometry. It was found that a significant reduction in protein adsorption is achieved as the comb polymer layer is sufficiently dense. For solution adsorption this was achieved by adsorption from high pH solutions. On the other hand, the best performance of the microcontact printed surfaces was obtained when the stamp was inked either at low or at high pH. For a given comb polymer layer thickness/poly(ethylene oxide) density, significant differences in protein repellant properties were observed between the different preparation methods, and it is suggested that a reduction in the mobility of the comb polymer layer generated by covalent attachment favors a reduced protein adsorption. © 2006 Elsevier Inc. All rights reserved.

  • 41.
    Lattemann, Martina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics .
    Ulrich, S.
    Forschungszentrum Karlsruhe.
    Ye, J.
    Forschungszentrum Karlsruhe.
    New approach in depositing thick, layered cubic boron nitride coatings by oxygen addition-structural and compositional analysis2006In: Thin solid films : an international journal on the science and technology of thin and thick films, Vol. 515, no 3, 1058-1062 p.Article in journal (Refereed)
    Abstract [en]

    Cubic boron nitride (c-BN) can be produced by PVD and PA-CVD techniques by intensive ion bombardment leading to highly stressed films limiting its use in industrial applications. Various attempts have been undertaken to reduce the compressive stress of c-BN thin films. A significant reduction in compressive stress and a substantially improved adhesion was achieved by a new coating concept consisting of a two-step adhesion-promoting base layer, a compositional-graded nucleation layer obtained by a stepwise decrease of the oxygen content in the Ar/N2/O2 atmosphere and a low-stressed c-BN:O top layer with controlled oxygen addition. The four-layer c-BN:O film with a thickness of 3 ìm was deposited by unbalanced radio frequency magnetron sputtering of a hot-pressed hexagonal boron nitride target on silicon substrates. The adhesion layer was deposited in a mixed Ar/O2 atmosphere of 0.26 Pa with a stepwise increased nitrogen gas flow and a subsequent increase of the ion energy by increasing the substrate bias from 0 to − 250 V. The c-BN nucleation was gradually initiated by decreasing the O2 gas flow. The present study was focused on the investigation of the morphology, the microstructure on the nanoscale, and the bonding structure using scanning electron microscopy (SEM), Fourier-Transmission infra-red spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) employing analytical scanning transmission electron microscopy (ASTEM). The HRTEM images revealed a four-layer coating consisting of a gradual nucleation of t-BN, on which a gradual nucleation of c-BN was achieved by decreasing the oxygen gas flow.

  • 42.
    Hemmingsson, Carl
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Heuken, M.
    Schineller, B.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Growth of bulk GaN in a vertical hydride vapour phase epitaxy reactor2006In: Superlattices and Microstructures, ISSN 0749-6036, Vol. 40, no 4-6 SPEC. ISS., 205-213 p.Article in journal (Refereed)
    Abstract [en]

    Using the hydride vapour phase epitaxy technique, we have grown 2-inch diameter bulk GaN material with a thickness up to 2 mm. The growth was performed in a vertical hot-walled reactor at atmospheric pressure. In this geometry, the process gases are distributed from the bottom upwards through the reactor. We present recent results on growth and characterization of the bulk GaN material. The structural and optical properties of the layers have been studied using decorative etching, optical microscopy, scanning electron microscopy, X-ray diffraction, cathodoluminescence, and low temperature photoluminescence. © 2006 Elsevier Ltd. All rights reserved.

  • 43.
    Moshfegh, Ramin
    et al.
    Hållfasthetslära Tekniska fakultetet.
    Li, Xiangdong
    Nilsson, Larsgunnar
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Solid Mechanics.
    Gradient-based refinement indicators in adaptive finite element analysis with special reference to sheet metal forming2000In: Engineering computations, ISSN 0264-4401, Vol. 17, no 8, 910-932 p.Article in journal (Refereed)
    Abstract [en]

    Two mesh refinement indicators based on the gradients of effective stress (GSIG) and effective plastic strain (GEPS), respectively, are proposed for adaptive finite element analysis of the large deformation, quasi-static or dynamic response of shell structures. The mesh refinement indicators are based on equi-distributing the variation of stresses or plastic strains over the elements of the mesh. A program module is developed and implemented in the non-linear explicit finite element code LS-DYNA. This module provides element-wise refinement evaluations so that selective mesh refinements are carried out in regions of the mesh where the values of local indicators exceed a user-specified tolerance. The FE model of a conventional deep drawing process is used as a numerical model, including both material and geometrical non-linearities, in order to demonstrate the versatility of the two refinement indicators. Four different refinement indicators, based on angle change, thickness change, GSIG and GEPS, are applied in this investigation. The numerical results are compared with experimental results regarding the thickness distribution versus cup height, cup height variation versus circumference angle, effective plastic strain in the deformed sheet and punch force. It is shown that the proposed indicators can identify finite elements which have high gradients of effective stress or effective plastic strain so that the mesh is refined in the regions undergoing the most severe deformations and the numerical results are improved.

  • 44.
    Olhager, Elisabeth
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Pediatrics. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Forsum, Elisabet
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of surgery.
    Assessment of total body fat using the skinfold technique in full-term and preterm infants2006In: Acta Paediatrica, ISSN 0803-5253, Vol. 95, no 1, 21-28 p.Article in journal (Refereed)
    Abstract [en]

    Background: Assessment of body composition may be of interest when the nutritional status of infants is evaluated but is often difficult since simple and valid methods are lacking. With appropriate validation, measurements based on skinfold thickness (SFT) may be useful for this purpose. Aims: To evaluate the potential of a published method, based on measurements of SFT, to assess total body fat (TBF) of infants, and to calculate the fat content of adipose tissue (AT) in infants using previously published information regarding AT volume and total body water. Subjects and methods: Forty-five full-term infants and eight infants born in gestational weeks 31-33 were studied at a postnatal age of 4-131 and 44-75 d, respectively. The body water dilution method was used to obtain reference estimates of TBF (TBF-BWD). Results: In full-term infants, TBF assessed using the skinfold method (TBF-SFT) minus TBF-BWD was 1.5±10.8% (mean±2 SD). Furthermore, TBF-SFT minus TBF-BWD (%, y) was correlated (p <0.0001) with the average of TBF-SFT and TBF-BWD (%, x), showing that TBF-SFT was too high in lean infants and too low in infants with more TBF. In the full-term infants, AT contained 0.68±0.14 g fat/ml. In the premature infants, TBF-SFT (%), TBF-BWD (%) and the AT fat content were similar to the corresponding figures in nine full-term newborns. Conclusion: The results indicate that the SFT method produced inaccurate and biased estimates of TBF in infants. A considerable variation between infants regarding their AT fat content may be an important reason for these findings. © 2006 Taylor & Francis.

  • 45. Paskova, T.
    et al.
    Hommel, D.
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Darakchieva, Vanya
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Bockowski, M.
    Suski, T.
    Grzegory, I.
    Tuomisto, T.
    Saarinen, K.
    Ashkenov, N.
    Schubert, M.
    Effect of high-temperature annealing on the residual strain and bending of freestanding GaN films grown by hydride vapor phase epitaxy2006In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 88, no 14, 141909- p.Article in journal (Refereed)
    Abstract [en]

    The effect of high-temperature high-pressure annealing on the residual strain, bending, and point defect redistribution of freestanding hydride vapor phase epitaxial GaN films was studied. The bending was found to be determined by the difference in the in-plane lattice parameters in the two faces of the films. The results showed a tendency of equalizing the lattice parameters in the two faces with increasing annealing temperature, leading to uniform strain distribution across the film thickness. A nonmonotonic behavior of structural parameters with increasing annealing temperature was revealed and related to the change in the point defect content under the high-temperature treatment. © 2006 American Institute of Physics.

  • 46.
    Laska, Matthias
    et al.
    University of Munich Medical School.
    Rivas Bautista, Rosa Mariela
    Instituto de Neuro-Etologia Universidad Veracruzana, Mexico.
    Hernandez Salazar, Laura Teresa
    Instituto de Neuro-Etologia Universidad Veracruzana, Mexico.
    Olfactory Sensitivity for Aliphatic Alcohols and Aldehydes in Spider Monkeys (Ateles geoffroyi)2006In: American Journal of Physical Anthropology, ISSN 0002-9483, E-ISSN 1096-8644, Vol. 129, 112-120 p.Article in journal (Refereed)
    Abstract [en]

    A simple and general method for the preparation of ultrathin, large-area, free-standing films of nanofibrous composite materials was developed. First, positively charged cadmium hydroxide nanostrands of 1.9 nm in diameter and micrometers in length were prepared by mixing dilute aqueous solutions of cadmium chloride and aminoethanol. Negatively charged dye molecules, proteins, nanoparticles, and watersoluble fullerene or carbon nanotubes were mixed with the nanostrands to give a well-dispersed solution of the corresponding nanofibrous composites. After filtration of the dispersions with a polycarbonate membrane filter, uniform films with a thickness of a few tens to hundreds of nanometers and a diameter of a few centimeters were obtained. The films were readily peeled off from the membrane filter by immersion in ethanol. The resultant free-standing films could be further transferred to other substrates, such as quartz plate, gold electrode, and porous alumina membrane, and were characterized by scanning and transmission electron microscopies. We provide herein various nanofibrous free-standing films with optical, biological, metallic, and magnetic properties.

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

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

  • 48.
    Nyström, Fredrik
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Internal Medicine. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Malmqvist, K
    KI, Stockholm.
    Lind, L
    Universitetssjukhuset i Uppsala.
    Kahan, T
    KI, Stockholm.
    Nurse-recorded clinic and ambulatory blood pressures correlate equally well with left ventricular mass and carotid intima-media thickness2005In: Journal of Internal Medicine, ISSN 0954-6820, Vol. 257, no 6, 514-522 p.Article in journal (Refereed)
    Abstract [en]

    Objective. To assess relationships between noninvasive ambulatory blood pressure (BP), clinic BP (mean value of three readings in the seated position measured by nurses), structural cardiac indices, intima-media thickness of the common carotid artery and several hormones. Design. Cross-sectional study of 75 subjects with hypertension and left ventricular hypertrophy (HTH) according to echocardiography, 35 subjects with hypertension and normal left ventricular dimensions (HT) and 23 normotensive subjects (NT). Results. We found an excellent correlation between mean 24-h ambulatory BP and clinic BP, the r-value for systolic BP being 0.82 and for diastolic levels 0.78 (both P < 0.0001). Clinic and ambulatory BP correlated equally well with left ventricular (LV) mass index (r-values between 0.55 and 0.64, all P < 0.0001) and to intima-media thickness of the carotid artery (r = 0.18-0.34, P < 0.01). The systolic white-coat effect (clinic BP - day-time BP) was higher in the HTH and HT compared with NT and was weakly correlated to LV mass index (r = 0.18, P = 0.04). Nondippers (mean arterial night/day BP ratio of >0.9) had higher brain (6.1 ± 7.5 pmol L-1 vs. 3.7 ± 3.2 pmol L-1, P = 0.01) and atrial (14 ± 3.4 pmol L-1 vs. 9.3 ± 5.4 pmol L-1, P = 0.04) natriuretic peptide levels, and also exhibited a lower ejection fraction (49 ± 8% vs. 57 ± 9%, P = 0.006), than dippers. Conclusion. Clinic BP recordings performed by nurses as three measurements 1 min apart provide excellent relationship to target organ damage. Nondippers exhibited signs of a more advanced hypertensive organ damage than dippers which corresponds well with the poor prognosis linked to this condition. © 2005 Blackwell Publishing Ltd.

  • 49.
    Jonsson, Rolf
    et al.
    FOI, Linköping.
    Wahab, Qamar Ul
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Rudner, Staffan
    FOI, Linköping.
    Svensson, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronic Devices.
    Computational load pull simulations of SiC microwave power transistors2003In: Solid-State Electronics, ISSN 0038-1101, Vol. 47, no 11, 1921-1926 p.Article in journal (Refereed)
    Abstract [en]

    The design of power transistors for microwave applications requires a good understanding of their large signal behaviour in a real circuit context. The computational load-pull simulation technique is a powerful new way to evaluate the full time-domain voltages and currents of microwave power transistors during realistic operation. With this method it is possible to relate details in the time domain voltages and currents to corresponding variations in carrier densities, electrical field, etc. in the device. We have utilised the standard device simulator Medici, directly driven by sine voltage sources on both input and output. The resulting data from the simulations was then analysed using Matlab. Several 4H-SiC MESFET structures were evaluated by this technique and we found the p-type buffer layer doping and thickness to be crucial to obtain an optimum RF power. A 4H-SiC MESFET structure was found to have an output power of 6.2 W/mm at 1 GHz. ⌐ 2003 Elsevier Ltd. All rights reserved.

  • 50.
    Edman Jönsson, Gustav
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Sputtring av Ti-Si-C-Ag beläggningar från sammansatta sputterkällor2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today gold is used as contact material on electric contacts for low current applications. Gold, however,has low wear resistance, is expensive and environmentally stressful to produce. An alternative contactmaterial to gold is nano composite Ti-Si-C-Ag deposited with DC-magnetron sputtering. Nanocomposite Ti-Si-C-Ag has so far been deposited by a compound Ti-Si-C sputter source with a separateAg source.

    In this work films have been deposited by three different compound Ti-Si-C-Ag sources with threedifferent carbon contents. The films have been deposited in two separate PVD systems: Oneconventional batch loaded and one sequential with a load-lock.

    The phase- and elemental composition of the films has been studied with XRD and EDX respectively.Thickness and microstructure have been analysed with SEM. Adhesion and resistivity has beenanalysed with Rockwell indentation and surface resistivity measurement with four point probe. Contactresistance has also been studied to a limited extent.

    The work shows that the increment of carbon content in the source yields more carbon rich films withlarger titanium carbide crystallites. The resistivity is increasing due to an increased amorphous phasebetween the crystallites but the contact resistance is decreasing due to a more ductile film.

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