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  • 4801.
    Zhou, Nian
    et al.
    Dept of Materials Science, Dalarna University, Sweden.
    Peng, Ru
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska fakulteten.
    Pettersson, Rachel
    KTH och Jernkontoret, Stockholm.
    Schönning, Mikael
    Corrosion Dept, Avesta Research Centre, Outokumpu Stainless AB, Avesta.
    Residual Stress in Stainless Steels after Surface Grinding and its Effect on Chloride Induced SCC2017Ingår i: Residual Stresses 2016: ICRS-10, Materials Research Proceedings 2 (2017), Materials Research Forum , 2017, Vol. 2, 289-294 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The induced residual stresses in stainless steels as a consequence of surface grinding as well as their influence on the chloride induced stress corrosion cracking (SCC) susceptibility have been investigated. Three types of materials were studied: 304L austenitic stainless steel, 509 ferritic stainless steel and 2304 duplex stainless steel. Surface grinding using 60# and 180# grit size abrasives was performed for each material. Residual stress depth profiles were measured using X-ray diffraction. The susceptibility to stress corrosion cracking was evaluated in boiling MgCl2 according to ASTM G36. Specimens were exposed without applying any external loading to evaluate the risk for SCC caused solely by residual stresses. Induced residual stresses and corrosion behavior were compared between the austenitic, ferritic and duplex stainless steels to elucidate the role of the duplex structure. For all materials, the grinding operation generated tensile residual stresses in the surface along the grinding direction but compressive residual stresses perpendicular to the grinding direction. In the subsurface region, compressive stresses in both directions were present. Microcracks initiated due to high grinding-induced tensile residual stresses in the surface layer were observed in austenitic 304L and duplex 2304, but not in the ferritic 4509. The surface residual stresses decreased significantly after exposure for all specimens.

  • 4802.
    Zhou, Nian
    et al.
    Dept of Materials Science, Dalarna University, Sweden.
    Peng, Ru
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska fakulteten.
    Schönning, Mikael
    Corrosion Dept, Avesta Research Centre, Outokumpu Stainless AB, Avesta.
    Pettersson, Rachel
    KTH och Jernkontoret, Stockholm.
    SCC of 2304 Duplex Stainless Steel - Microstructure, Residual Stress and Surface Grinding Effects2017Ingår i: Materials, ISSN 1996-1944, Vol. 10, nr 221Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental.

  • 4803.
    Zhou, Nian
    et al.
    Dept of Materials Science, Dalarna University, Sweden.
    Pettersson, Rachel
    KTH och Jernkontoret, Stockholm.
    Peng, Ru Lin
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska fakulteten.
    Schönning, Mikael
    Corrosion Dept, Avesta Research Centre, Outokumpu Stainless AB, Avesta.
    Effect of Surface Grinding on Chloride Induced SCC of 304L2016Ingår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 658, 50-59 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of surface grinding on the stress corrosion cracking (SCC) behavior of 304L austenitic stainless steel in boiling magnesium chloride has been investigated. SCC tests were conducted both without external loading and with varied levels of four-point bend loading for as-delivered material and for specimens which had been ground parallel or perpendicular to the loading direction. Residual stresses due to the grinding operation were measured using the X-ray diffraction technique. In addition, surface stress measurements under applied load were performed before exposure to evaluate the deviation between actual applied loading and calculated values according to ASTM G39. Micro-cracks initiated by a high level of tensile residual stress in the surface layer were observed for all the ground specimens but not those in the as-delivered condition. Grinding along the loading direction increased the susceptibility to chloride induced SCC; while grinding perpendicular to the loading direction improved SCC resistance. Surface tensile residual stresses were largely relieved after the initiation of cracks.

  • 4804.
    Zhou, Shuai
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten. Beijing University of Posts and Telecommun, Peoples R China; China International Telecommunication Construction Group Design Institute Co., Ltd, Beijing, Peoples R China.
    Liu, Yumin
    Beijing University of Posts and Telecommun, Peoples R China.
    Wang, Donglin
    Beijing University of Posts and Telecommun, Peoples R China.
    Yu, Zhongyuan
    Beijing University of Posts and Telecommun, Peoples R China.
    Zhao, Wei
    China Int Telecommun Construct Grp Design Institute Co, Peoples R China.
    Le, Lifeng
    China Int Telecommun Construct Grp Design Institute Co, Peoples R China.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    The calculation of InGaN quantum dot formation mechanism on GaN pyramid2015Ingår i: Superlattices and Microstructures, ISSN 0749-6036, E-ISSN 1096-3677, Vol. 84, 72-79 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An equilibrium approach is used to calculate the free energy and composition distribution of InGaN/GaN quantum dot located on the InGaN/GaN pyramid. The energy balance method is adopted to predict critical conditions for quantum dot formation. We find that the formation of QD depends strongly on the size of pyramid top surface. The results can fit our experiment qualitatively.

  • 4805.
    Zhou, Xiaowei
    et al.
    Ocean University of China, China.
    Zhong, Guoqiang
    Ocean University of China, China.
    Qi, Lin
    Ocean University of China, China.
    Dong, Junyu
    Ocean University of China, China.
    Pham, Tuan
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Mao, Jianzhou
    Macau Univ. of Science and Technology, China.
    Surface height map estimation from a single image using convolutional neural networks2017Ingår i: Proceedings of SPIE, Eighth International Conference on Graphic and Image Processing, SPIE - International Society for Optical Engineering, 2017, Vol. 10225, UNSP 1022524-1Konferensbidrag (Refereegranskat)
  • 4806.
    Zhou, Yi
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Antenehe Gedefaw, Desta
    University of Addis Ababa.
    Hellstrom, Stefan
    Chalmers.
    Kratschmer, Ilse
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Mammo, Wendimagegn
    University of Addis Ababa.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats R
    Chalmers.
    Black Polymers in Bulk-Heterojunction Solar Cells2010Ingår i: IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, ISSN 1077-260X, Vol. 16, nr 6, 1565-1572 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The active materials in polymer solar cells have a decisive role on the performance of the cells. Polymers with extended absorption, i.e., black polymers with absorption covering the whole visible region are desired in order to capture the important parts of the solar irradiation. Different ways of achieving black active materials are discussed and two new alternating polyfluorene (APFO) copolymers with broad absorption, APFO-Black 1 and APFO-Black 2, using two different design strategies are described. The UV-Vis absorption spectra of the polymers extend to approximately 850 nm, and the polymers were used as donors and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM)[60] or PCBM[70] as acceptors in solar cell devices in various mixing ratios. The best combinations yielded an overall power conversion efficiency of 1.2% for APFO-Black 1 and 1.5% for APFO-Black 2.

  • 4807.
    Zhou, Yi
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Tvingstedt, Kristofer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Du, Chunxia
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Ni, Wei-Xin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats R
    Chalmers, Dept Chem & Biol Engn.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Observation of a Charge Transfer State in Low-Bandgap Polymer/Fullerene Blend Systems by Photoluminescence and Electroluminescence Studies2009Ingår i: ADVANCED FUNCTIONAL MATERIALS, ISSN 1616-301X, Vol. 19, nr 20, 3293-3299 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The presence of charge transfer states generated by the interaction between the fullerene acceptor PCBM and two alternating copolymers of fluorene with donor-acceptor-donor comonomers are reported; the generation leads to modifications in the polymer bandgap and electronic structure. In one of polymer/fullerene blends, the driving; force for photocurrent generation, i.e., the gap between the lowest unoccupied molecular orbitals of the donor and acceptor, is only 0.1 eV, but photocurrent is generated. It is shown that the presence of a charge transfer state is more important than the driving force. The charge transfer states are visible through new emission peaks in the photoluminescence spectra and through electroluminescence at a forward bias. The photoluminescence can be quenched under reverse bias, and can be directly correlated to the mechanism of photocurrent generation. The excited charge transfer state is easily dissociated into free charge carriers, and is an important intermediate state through which free charge carriers are generated.

  • 4808.
    Zhou, Yinhua
    et al.
    Jilin University.
    Li, Fenghong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Barrau, Sophie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Tian, Wenjing
    Jilin University.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Inverted and transparent polymer solar cells prepared with vacuum-free processing2009Ingår i: SOLAR ENERGY MATERIALS AND SOLAR CELLS, ISSN 0927-0248, Vol. 93, nr 4, 497-500 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Inverted transparent polymer solar cells were fabricated by sequentially depositing several organic layers from fluids, on ITO/glass substrates. ITO was used as a cathode to collect electrons. The photovoltage of these diodes can be increased by up to 400 mV by inserting a buffer layer of polyethylene oxide between ITO and the active layers, which results in 4-fold enhancement of power conversion efficiency under the illumination of 100 mW/cm(2) simulated AM1.5 solar light. The enhancement of V., is consistent with the work function change between ITO and ITO/PEO measured by photoelectron spectroscopy. Solar cell production without vacuum processing may lower production costs.

  • 4809.
    Zhu, Baiwei
    et al.
    Jonköping University, Sweden.
    Seifeddine, Salem
    Jonköping University, Sweden.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Jarfors, Anders E. W.
    Jonköping University, Sweden.
    Leisner, Peter
    Jonköping University, Sweden; SP Technical Research Institute Sweden, Sweden.
    Zanella, Caterina
    Jonköping University, Sweden.
    A study of formation and growth of the anodised surface layer on cast Al-Si alloys based on different analytical techniques2016Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 101, 254-262 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper aims to investigate the mechanisms of formation and growth of the anodised surface layer on Al-Si castings by applying different analytical techniques such as optical microscopy, scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and X-ray computer tomography (X-ray CT) scanning. Three different Al alloys with various Si content (2.43%, 3.53% and 5.45%) were investigated. Si particle morphological modification by Sr addition, as well as directional solidification, was used to vary the microstructural coarseness in a controlled manner to study the influence of these parameters on the growth behaviour of the oxide layer. This study observed residual unanodised Al phases trapped beneath or between Si particles in the oxide layer. It was found, depending on the geometry and morphology of Si particles, that Al can be shielded by Si particles and prevented from oxidising. (C) 2016 Elsevier Ltd. All rights reserved.

  • 4810.
    Zhu, Yurong
    Linköpings universitet, Matematiska institutionen, Matematisk statistik. Linköpings universitet, Tekniska fakulteten.
    Large Deviations on Longest Runs2016Studentarbete övrigt, 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The study on the longest stretch of consecutive successes in \random" trials dates back to 1916 when the German philosopher Karl Marbe wrote a paper concerning the longest stretch of consecutive births of children of the same sex as appearing in the birth register of a Bavarian town. The result was actually used by parents to \predict" the sex of their children. The longest stretch of same-sex births during that time in 200 thousand birth registrations was actually 17 t log2(200 103): During the past century, the research of longest stretch of consecutive successes (longest runs) has found applications in various areas, especially in the theory of reliability. The aim of this thesis is to study large deviations on longest runs in the setting of Markov chains. More precisely, we establish a general large deviation principle for the longest success run in a two-state (success or failure) Markov chain. Our tool is based on a recent result regarding a general large deviation for the longest success run in Bernoulli trails. It turns out that the main ingredient in the proof is to implement several global and local estimates of the cumulative distribution function of the longest success run.

  • 4811.
    Zhuang, Wenliu
    et al.
    Chalmers, Sweden .
    Zhen, Hongyu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Kroon, Renee
    Chalmers, Sweden .
    Tang, Zheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Hellstrom, Stefan
    Chalmers, Sweden .
    Hou, Lintao
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Wang, Ergang
    Chalmers, Sweden .
    Gedefaw, Desta
    Chalmers, Sweden .
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats R.
    Chalmers, Sweden .
    Molecular orbital energy level modulation through incorporation of selenium and fluorine into conjugated polymers for organic photovoltaic cells2013Ingår i: JOURNAL OF MATERIALS CHEMISTRY A, ISSN 2050-7488, Vol. 1, nr 43, 13422-13425 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrated an effective chemical approach to modulate the energy levels of conjugated polymers by synergistically combining fluorine substitution and thiophene-selenophene exchange. Such modifications from TQ1 resulted in a significantly enhanced open-circuit voltage up to 1.0 V while retaining high photovoltaic performance.

  • 4812.
    Zhybak, Mikael T
    et al.
    Institute of Molecular Biology and Genetics, NAS of Ukraine, Ukraine.
    Fayura, L.Y.
    Institute of Cell Biology, NAS of Ukraine, Ukraine.
    Boretsky, Yu R
    Institute of Cell Biology, NAS of Ukraine, Ukraine.
    Dempsey, Eithne
    Centre for Research in Electroanalytical Technologies, Ireland.
    Gonchar, M.V.
    Institute of Cell Biology, NAS of Ukraine, Ukraine.
    Sibirny, A.A.
    Institute of Cell Biology, NAS of Ukraine, Ukraine.
    Turner, Anthony
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Korpan, Yaroslav
    Institute of Molecular Biology and Genetics, NAS of Ukraine, Ukraine.
    Novel L-arginine amperometric assay based on recombinant arginine deiminase and Nafion/PANi composite2016Ingår i: Biosensors 2016 – The World Congress on Biosensors, Elsevier, 2016Konferensbidrag (Övrigt vetenskapligt)
  • 4813.
    Zhybak, M.T.
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten. Laboratory of Biomolecular Electronics, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine.
    Beni, Valerio
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemiska och optiska sensorsystem. Linköpings universitet, Tekniska fakulteten.
    Dempsey, Eithne
    Centre for Research in Electroanalytical Technologies, Department of Science, ITT Dublin, Tallaght, Dublin, Ireland.
    Turner, Anthony
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Korpan, Y
    Laboratory of Biomolecular Electronics, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine,Kyiv, Ukraine.
    Creatinine and urea biosensors based on a novel ammonium ion-selective copper-polyaniline nano-composite2016Ingår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 77, 505-511 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of a novel ammonium ion-specific copper-polyaniline nano-composite as transducer for hydrolase-based biosensors is proposed. In this work, a combination of creatinine deaminase and urease has been chosen as a model system to demonstrate the construction of urea and creatinine biosensors to illustrate the principle. Immobilisation of enzymes was shown to be a crucial step in the development of the biosensors; the use of glycerol and lactitol as stabilisers resulted in a significant improvement, especially in the case of the creatinine, of the operational stability of the biosensors (from few hours to at least 3 days). The developed biosensors exhibited high selectivity towards creatinine and urea. The sensitivity was found to be 85±3.4 mA M−1 cm−2 for the creatinine biosensor and 112±3.36 mA M−1 cm−2 for the urea biosensor, with apparent Michaelis–Menten constants (KM,app), obtained from the creatinine and urea calibration curves, of 0.163 mM for creatinine deaminase and 0.139 mM for urease, respectively. The biosensors responded linearly over the concentration range 1–125 µM, with a limit of detection of 0.5 µM and a response time of 15 s.

    The performance of the biosensors in a real sample matrix, serum, was evaluated and a good correlation with standard spectrophotometric clinical laboratory techniques was found.

  • 4814.
    Zhybak, Mykhailo T.
    et al.
    National Academic Science Ukraine, Ukraine.
    Fayura, Lyubov Y.
    NAS Ukraine, Ukraine.
    Boretsky, Yuriy R.
    Lviv State University of Phys Culture, Ukraine.
    Gonchar, Mykhailo V.
    NAS Ukraine, Ukraine.
    Sibirny, Andriy A.
    NAS Ukraine, Ukraine; Rzeszow University, Poland.
    Dempsey, Eithne
    ITT Dublin, Ireland.
    Turner, Anthony
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Korpan, Yaroslav I.
    National Academic Science Ukraine, Ukraine.
    Amperometric L-arginine biosensor based on a novel recombinant arginine deiminase2017Ingår i: Microchimica Acta, ISSN 0026-3672, E-ISSN 1436-5073, Vol. 184, nr 8, 2679-2686 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The authors describe an amperometric biosensor for the amino acid L-arginine (L-Arg). It is based on the use of a Nafion/Polyaniline (PANi) composite on a platinum screen-printed electrode (Pt-SPE) using a novel recombinant arginine deiminase isolated from Mycoplasma hominis. The protein was over-expressed, purified and employed as a biorecognition element of the sensor. Enzymatic hydrolysis of L-Arg leads to the formation of ammonium ions which diffuse into the Nafion/PANi layer and induce the electroreduction of PANi at a potential of -0.35 V (vs Ag/AgCl). L-Arg sensitivity is 684 +/- 32 A.M-1.m(-2), and the apparent Michaelis-Menten constant K-M(app)) is 0.31 +/- 0.05 mM. The calibration plot is linear over the range 3-200 mu M L-Arg, the limit of detection is 1 mu M, and the response time (for 90% of the total signal change to occur) is 15 s. The sensor is selective and exhibits good storage stability (amp;gt; 1 month without loss in signal). The biosensor was applied to the analysis of L-Arg in pharmaceutical samples and of ammonium and L-Arg in spiked human plasma obtained from blood of healthy volunteers and those with a hepatic disorder. Data generated were found to be in good agreement with a reference fluorometric enzymatic assay.

    Publikationen är tillgänglig i fulltext från 2018-05-02 12:48
  • 4815.
    Zhybak, Mykhailo T.
    et al.
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för fysik, kemi och biologi. Institute of Molecular Biology and Genetics, NAS of Ukraine, Kyiv, 03680, Ukraine .
    Vagin, Mikhail Yu.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Beni, Valerio
    ACREO Swedish ICT, -601 74, Norrköping, SE, Sweden .
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Dempsey, Eithne
    Centre for Research in Electroanalytical Technologies, Department of Science, Institute of Technology Tallaght, Tallaght, Dublin, Ireland .
    Turner, Anthony P. F.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Korpan, Yaroslav I.
    Institute of Molecular Biology and Genetics, NAS of Ukraine, Kyiv, 03680, Ukraine .
    Direct detection of ammonium ion by means of oxygen electrocatalysis at a copper-polyaniline composite on a screen-printed electrode.2016Ingår i: Microchimica Acta, ISSN 0026-3672, E-ISSN 1436-5073, Vol. 183, nr 6, 1981-1987 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel electrocatalytic material for oxygen reduction, based on polyaniline in combinationwith copper, was developed and utilised for the direct voltammetric quantification of ammonium ions. Consecutive electrode modification by electrodeposited copper, a Nafion membrane and electropolymerised polyaniline resulted in an electrocatalytic composite material which the retained conductivity at neutral pH. Ammonia complex formation with Cu (I) caused the appearance of oxygen electrocatalysis, which was observed as an increase in cathodic current. This Faradaic phenomenon offered the advantage of direct voltammetric detection and was utilised for ammonium electroanalysis. The developed quantification protocol was applied for ammonium assay in human serum and compared with the routine approach for clinical analysis.

  • 4816.
    Zidar, Josefina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    The relationship between personality and cognitionin the fowl, Gallus gallus2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    To cope with a changing environment, animals have traditionally been considered to behave adaptively to each situation faced. Yet, individual behavioural responses can both differ widely within populations, and show between-individual consistency (i.e. describing variation in animal personality). In this thesis, I focus on individual differences in animal personality and cognition (i.e. how animals perceive, process, store and act on environmental stimuli), and explore the possibility that they are interlinked. I use domestic- and red junglefowl (Gallus gallus ssp.), a species that is cognitively, behaviourally and socially complex, to explore these aspects of behaviour, through a series of studies.

    Animal personality and coping styles are frequently used terms to describe within- and between-individual differences in behaviour, which are consistent over time and across various situations. The terms are often used as synonyms, even though they differ in some respects. In paper I, I show that animal personality and coping styles can be measured in red junglefowl, and that behavioural flexibility might be an important aspect for both. Further, I show that the terms should not be used as synonyms since they describe different aspects of behavioural variation.

    In paper II, I observe large individual variation in both personality traits and learning speed in both chicks and adult red junglefowl. Interestingly, learning performance does not correlate across tasks, contrasting what has been found in humans and rodents. Thus, individuals that learn rapidly in one task are not necessarily fast learners in another task. I observe a relationship between personality and cognition that is task- and age-dependent, in which exploration relates to learning speed, but in opposite directions for chicks compared to adult females. In paper III, I show that red junglefowl chicks that are more behaviourally flexible have a stronger preference for new generalised stimuli, than less behaviourally flexible chicks. Behavioural flexibility was associated with fearfulness, indicating variation in reactive-proactive coping styles. In paper IV, I show that early cognitive stimulation to some extent can affect adult personality, thus showing a causal relationship between personality and cognition. Not all personality traits were affected, which might depend on the type of cognitive stimulation chicks were exposed to.

    Important cognitive processes like perception and decision-making, can contain biases. One such bias is called judgment bias, which describes how individuals interpret ambiguous stimuli on a scale from positive to negative (optimism to pessimism). In paper V, I show that alteration of emotional state can influence such biases. Here, unpredictable stress influence judgment bias negatively, when individuals are housed in simpler, but not in complex environments, suggesting that there is an effect of additive stress that lead to reduced optimism. Complexity instead seems to buffer against negative effects of stress, since individuals in complex environments remained optimistic after stress exposure. Furthermore, increased dopamine activity was associated with optimism in chicks. In paper VI, I find that aspects of personality associate with how chicks judge ambiguity. Highly active individuals are more likely to approach cues than less active individuals, and when approaching, individuals that are slow to approach ambiguous cues are more vigilant when assayed in personality assays. Vigilant individuals might be more worried and reactive, which suggest that emotional traits can influence responses in a judgment bias task.

    Taken together, I show consistent behavioural differences among individuals describing personality and coping styles, and variation in cognition. I show that these traits are related, and that there is an interplay between them, in which cognition can influence personality, and vice versa. I further show that judgment may be affected by the individual’s current affective state and personality. Thus, I show a complex relationship between personality and cognition that in combination with environmental effects can help explain behavioural variation.

  • 4817.
    Zidar, Josefina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Balogh, Alexandra
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska högskolan.
    Favati, Anna
    Stockholm University, Sweden.
    Jensen, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Leimar, Olof
    Stockholm University, Sweden.
    Lovlie, Hanne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    A comparison of animal personality and coping styles in the red junglefowl2017Ingår i: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 130, 209-220 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is an increased focus in biology on consistent behavioural variation. Several terms are used to describe this variation, including animal personality and coping style. Both terms describe between individual consistency in behavioural variation; however, they differ in the behavioural assays typically used, the expected distribution of response variables, and whether they incorporate variation in behavioural flexibility. Despite these differences, the terms are often used interchangeably. We conducted experiments using juvenile and adult red junglefowl, Gallus gallus, as subjects to explore the degree to which animal personality and coping styles overlap. We demonstrate that animal personality and coping styles can be described in this species, and that shyer individuals had more flexible responses, as expected for coping styles. Behavioural responses from both personality and coping style assays had continuous distributions, and were not clearly separated into two types. Behavioural traits were not correlated and, hence, there was no evidence of a behavioural syndrome. Further, behavioural responses obtained in personality assays did not correlate with those from coping style tests. Animal personality and coping styles are therefore not synonymous in the red junglefowl. We suggest that the terms animal personality and coping style are not equivalent and should not be used interchangeably. (C) 2017 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

    Publikationen är tillgänglig i fulltext från 2019-07-22 15:41
  • 4818.
    Zidar, Josefina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Sorato, Enrico
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Malmqvist, Ann-Marie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Jansson, Emelie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Rosher, Charlotte
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten. Faculty of Life Sciences, University of Manchester, Manchester, UK.
    Jensen, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Favati, Anna
    Department of Zoology, Stockholm University, Stockholm, Sweden.
    Løvlie, Hanne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Early experience affects adult personality in the red junglefowl: a role for cognitive stimulation?2017Ingår i: Behavioural Processes, ISSN 0376-6357, E-ISSN 1872-8308, Vol. 134, 78-86 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite intense research efforts, biologists are still puzzled by the existence of animal personality. While recent studies support a link between cognition and personality, the directionality of this relationship still needs to be clarified. Early-life experiences can affect adult behaviour, and among these, cognitive stimulation has been suggested theoretically to influence personality. Yet, the influence of early cognitive stimulation has rarely been explored in empirical investigations of animal behaviour and personality. We investigated the effect of early cognitive stimulation on adult personality in the red junglefowl (Gallus gallus). To this end, we assessed adult behaviour across a number of personality assays and compared behaviour of individuals previously exposed to a series of learning tasks as chicks, with that of control individuals lacking this experience. We found that individuals exposed to early stimulation as adults were more vigilant and performed fewer escape attempts in personality assays. Other behaviours describing personality traits in the fowl were not affected. We conclude that our results support the hypothesis that early stimulation can affect aspects of adult behaviour and personality, suggesting a hitherto underappreciated causality link between cognition and personality. Future research should aim to confirm these findings and resolve their underlying dynamics and proximate mechanisms.

    Publikationen är tillgänglig i fulltext från 2017-12-18 15:24
  • 4819.
    Ziemke, Tom
    Linköpings universitet, Institutionen för datavetenskap, Interaktiva och kognitiva system. Linköpings universitet, Tekniska fakulteten. Interaction Lab, School of Informatics, University of Skövde, Skövde, Swede.
    The body of knowledge: On the role of the living body in grounding embodied cognition2016Ingår i: Biosystems (Amsterdam. Print), ISSN 0303-2647, E-ISSN 1872-8324, Vol. 148, 4-11 s.Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Embodied cognition is a hot topic in both cognitive science and AI, despite the fact that there still is relatively little consensus regarding what exactly constitutes ‘embodiment’. While most embodied AI and cognitive robotics research views the body as the physical/sensorimotor interface that allows to ground computational cognitive processes in sensorimotor interactions with the environment, more biologically-based notions of embodied cognition emphasize the fundamental role that the living body – and more specifically its homeostatic/allostatic self-regulation – plays in grounding both sensorimotor interactions and embodied cognitive processes. Adopting the latter position – a multi-tiered affectively embodied view of cognition in living systems – it is further argued that modeling organisms as layered networks of bodily self-regulation mechanisms can make significant contributions to our scientific understanding of embodied cognition.

  • 4820.
    Zimmermann, F.
    et al.
    TU Bergakad Freiberg, Germany.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Gaertner, G.
    TU Bergakad Freiberg, Germany.
    Roeder, C.
    TU Bergakad Freiberg, Germany.
    Nguyen, Son Tien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Vesela, D.
    Research Centre Rez, Czech Republic.
    Lorincik, J.
    Research Centre Rez, Czech Republic.
    Hofmann, P.
    NaMLab gGmbH, Germany.
    Krupinski, M.
    NaMLab gGmbH, Germany.
    Mikolajick, T.
    NaMLab gGmbH, Germany; Technical University of Dresden, Germany.
    Habel, F.
    Freiberger Compound Mat GmbH, Germany.
    Leibiger, G.
    Freiberger Compound Mat GmbH, Germany.
    Heitmann, J.
    TU Bergakad Freiberg, Germany.
    Origin of orange color in nominally undoped HVPE GaN crystals2017Ingår i: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 70, 127-130 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this article we investigated unintentionally doped (UID) GaN grown by hydride vapor phase epitaxy (HVPE) with respect to point defects and impurity concentration. The samples were orange tinted to different extent. Optical analysis was performed by micro-photoluminescence and absorption spectroscopy. Absorption measurements revealed an absorption peak at 1.5 eV related to an internal transition in Mn3+ impurities and a second band with low energy onset at 1.9 eV, both increasing with the extent of orange color. Electron paramagnetic resonance investigations showed the presence of Mn2+ and Fe3+ in the colored crystals. The overall impurity concentration was verified by secondary ion mass spectrometry. Orange tint is associated with an increase of transition metal contamination, especially Mn. Based on these observations we suggest that the orange coloring in the investigated UID HVPE GaN samples is caused by the presence of Mn impurities. (C) 2017 Elsevier B.V. All rights reserved.

  • 4821.
    Zitinski Elias, Paula
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Gooran, Sasan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Nyström, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Multilevel Halftoning and Color Separation for Eight-Channel Printing2016Ingår i: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 60, nr 5, 50403Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multichannel printing employs additional colorants to achieve higher quality reproduction, assuming their physical overlap restrictions are met. These restrictions are commonly overcome in the printing workflow by controlling the colorant choice at each point. Our multilevel halftoning algorithm bundles inks of same hues in one channel with no overlap, separating them into eight channels, consequentially benefitting of increased ink options at each point. In this article, implementation and analysis of the algorithm is carried out. Color separation is performed using the cellular Yule‐Nielsen modified spectral Neugebauer model. The channels are binarized with the multilevel halftoning algorithm. The workflow is evaluated with an eight-channel inkjet at 600 dpi resulting in mean and maximum ΔE 94 color differences around 1 and 2, respectively. The halftoning algorithm is analyzed using S-CIELAB, thus involving the human visual system, in which multilevel halftoning showed improvement in terms of image quality compared to the conventional approach.

  • 4822.
    Zitinski Elias, Paula
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Gooran, Sasan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Nyström, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    MULTILEVEL HALFTONING AS AN ALGORITHM TO CONTROL INK OVERLAP IN MULTI-CHANNEL PRINTING2015Ingår i: 2015 COLOUR AND VISUAL COMPUTING SYMPOSIUM (CVCS), IEEE , 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    A multilevel halftoning algorithm can be used to overcome some of the challenges of multi-channel printing. In this algorithm, each channel is processed so that it can be printed using multiple inks of approximately the same hue, achieving a single ink layer. The computation of the threshold values required for ink separation and dot gain compensation pose an interesting challenge. Since the dot gain depends on the specific combination of ink, paper and print resolution, compensating the original image for multilevel halftoning means expressing the dot gain of multiple inks of same hue in terms of the coverage of a single ink. The applicability of the proposed multilevel halftoning workflow is demonstrated using chromatic inks while avoiding dot overlap and accounting for dot gain. The results indicate that the multilevel halftoned image is visually improved in terms of graininess when compared to bi-level halftoned images.

  • 4823.
    Zitinski Elias, Paula
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Nyström, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Gooran, Sasan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Color separation for improved perceived image quality in terms of graininess and gamut2017Ingår i: Color Research and Application, ISSN 0361-2317, E-ISSN 1520-6378, Vol. 42, nr 4, 486-497 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multi-channel printing employs additional inks to improve the perceived image quality by reducing the graininess and augmenting the printer gamut. It also requires a color separation that deals with the one-to-many mapping problem imposed when using more than three inks. The proposed separation model incorporates a multilevel halftoning algorithm, reducing the complexity of the print characterization by grouping inks of similar hues in the same channel. In addition, a cost function is proposed that weights selected factors influencing the print and perceived image quality, namely color accuracy, graininess and ink consumption. The graininess perception is qualitatively assessed using S-CIELAB, a spatial low-pass filtering mimicking the human visual system. By applying it to a large set of samples, a generalized prediction quantifying the perceived graininess is carried out and incorporated as a criterion in the color separation. The results of the proposed model are compared with the separation giving the best colorimetric match, showing improvements in the perceived image quality in terms of graininess at a small cost of color accuracy and ink consumption. (c) 2016 Wiley Periodicals, Inc.

  • 4824.
    Zobel, Valentin
    et al.
    Leipzig University, Leipzig, Germany.
    Reininghaus, Jan
    Institute of Science and Technology Austria, Klosterneuburg, Austria.
    Hotz, Ingrid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Visualizing Symmetric Indefinite 2D Tensor Fields using the Heat Kernel Signature2015Ingår i: Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data / [ed] Ingrid Hotz, Thomas Schultz, Cham: Springer, 2015, 257-267 s.Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The Heat Kernel Signature (HKS) is a scalar quantity which is derived from the heat kernel of a given shape. Due to its robustness, isometry invariance, and multiscale nature, it has been successfully applied in many geometric applications. From a more general point of view, the HKS can be considered as a descriptor of the metric of a Riemannian manifold. Given a symmetric positive definite tensor field we may interpret it as the metric of some Riemannian manifold and thereby apply the HKS to visualize and analyze the given tensor data. In this paper, we propose a generalization of this approach that enables the treatment of indefinite tensor fields, like the stress tensor, by interpreting them as a generator of a positive definite tensor field. To investigate the usefulness of this approach we consider the stress tensor from the two-point-load model example and from a mechanical work piece.

  • 4825.
    Zoulis, Georgios
    et al.
    Groupe d’Etudes des Semiconducteurs, Université Montpellier 2 and CNRS, cc 074‐GES, 34095 Montpellier Cedex 5, France.
    Sun, Jian Wu
    Groupe d’Etudes des Semiconducteurs, Université Montpellier 2 and CNRS, cc 074‐GES, 34095 Montpellier Cedex 5, France.
    Beshkova, Milena
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Vasiliauskas, Remigijus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Juillaguet, S.
    Groupe d’Etudes des Semiconducteurs, Université Montpellier 2 and CNRS, cc 074‐GES, 34095 Montpellier Cedex 5, France.
    Peyre, H.
    Groupe d’Etudes des Semiconducteurs, Université Montpellier 2 and CNRS, cc 074‐GES, 34095 Montpellier Cedex 5, France.
    Syväjärvi, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Camassel, J.
    Groupe d’Etudes des Semiconducteurs, Université Montpellier 2 and CNRS, cc 074‐GES, 34095 Montpellier Cedex 5, France.
    Investigation of Low Doped n-Type and p-Type 3C-SiC Layers Grown on 6H-SiC Substrates by Sublimation Epitaxy2010Ingår i: Silicon Carbide and Related Materials 2009, 2010, Vol. 645, 179-182 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Both, n-type and p-type 3C-SiC samples grown on 6H-SiC substrates by sublimation epitaxy have been investigated. From low temperature photoluminescence studies, we demonstrate a low level of residual (n and/or p-type) doping with weak compensation, which is confirmed by secondary ion mass spectroscopy in the case of p-type samples.

  • 4826.
    Zuo, Guangzheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Abdalla, Hassan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Kemerink, Martijn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Impact of doping on the density of states and the mobility in organic semiconductors2016Ingår i: PHYSICAL REVIEW B, ISSN 2469-9950, Vol. 93, nr 23, 235203- s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We experimentally investigated conductivity and mobility of poly(3-hexylthiophene) (P3HT) doped with tetrafluorotetracyanoquinodimethane (F(4)TCNQ) for various relative doping concentrations ranging from ultralow (10(-5)) to high (10(-1)) and various active layer thicknesses. Although the measured conductivity monotonously increases with increasing doping concentration, the mobilities decrease, in agreement with previously published work. Additionally, we developed a simple yet quantitative model to rationalize the results on basis of a modification of the density of states (DOS) by the Coulomb potentials of ionized dopants. The DOS was integrated in a three-dimensional (3D) hopping formalism in which parameters such as energetic disorder, intersite distance, energy level difference, and temperature were varied. We compared predictions of our model as well as those of a previously developed model to kinetic Monte Carlo (MC) modeling and found that only the former model accurately reproduces the mobility of MC modeling in a large part of the parameter space. Importantly, both our model and MC simulations are in good agreement with experiments; the crucial ingredient to both is the formation of a deep trap tail in the Gaussian DOS with increasing doping concentration.

  • 4827.
    Zuo, Guangzheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Li, Zhaojun
    Chalmers, Sweden.
    Andersson, Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Abdalla, Hassan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Wang, Ergang
    Chalmers, Sweden.
    Kemerink, Martijn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Molecular Doping and Trap Filling in Organic Semiconductor Host-Guest Systems2017Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, nr 14, 7767-7775 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate conductivity and mobility of different hosts mixed with different electron-withdrawing guests in concentrations ranging from ultralow to high. The effect of the guest material on the mobility and conductivity of the host material varies systematically with the guests LUMO energy relative to the host HOMO, in quantitative agreement with a recently developed model. For guests with a LUMO within similar to 0.5 eV of the host HOMO the dominant process governing transport is the competition between the formation of a deep tail in the host DOS and state filling. In other cases, the interaction with the host is dominated by any polar side groups on the guest and changes in the host morphology. For relatively amorphous hosts the latter interaction can lead to a suppression of deep traps, causing a surprising mobility increase by 1-2 orders of magnitude. In order to analyze our data, we developed a simple method to diagnose both the presence and the filling of traps.

    Publikationen är tillgänglig i fulltext från 2018-03-13 15:22
  • 4828.
    Zuo, Xiao
    et al.
    Chinese Academic Science, Peoples R China; Chinese Academic Science, Peoples R China.
    Ke, Peiling
    Chinese Academic Science, Peoples R China; Chinese Academic Science, Peoples R China.
    Chen, Rende
    Chinese Academic Science, Peoples R China.
    Li, Xiaowei
    Chinese Academic Science, Peoples R China.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Wang, Aiying
    Chinese Academic Science, Peoples R China; Chinese Academic Science, Peoples R China.
    Discharge state transition and cathode fall thickness evolution during chromium HiPIMS discharge2017Ingår i: Physics of Plasmas, ISSN 1070-664X, E-ISSN 1089-7674, Vol. 24, nr 8, 083507Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The temporal evolutions of target voltage and current waveforms under different pulse voltage and working pressure conditions were studied during Cr high power impulse magnetron sputtering discharges. Target voltage and current characteristics demonstrated that when the pulse width was set as 200 mu s, HiPIMS discharge went through a four-stage sequence during each pulse, Townsend discharge, glow discharge, afterglow, and pulse-off stages. A discharge state transition in the glow discharge stage happened at high pulse voltage and working pressure conditions. Furthermore, the dependence of reduced cathode fall thickness pdcon pulse voltage, working pressure, and normalized current density j/p(2) was presented. It was found that gas rarefaction leads to a change of relationship between pd(c) and j/p(2). A noticeable increase of the cathode fall thickness caused by gas rarefaction has been found. Published by AIP Publishing.

  • 4829.
    Zupan, Manja
    et al.
    Swedish University of Agricultural Sciences, Department of Animal Environment and Health, Box 7068, Uppsala, SE-750 07, Uppsala, Sweden.
    Buskas, Julia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Altimiras, Jordi
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Keeling, Linda J.
    Swedish University of Agricultural Sciences, Department of Animal Environment and Health, Box 7068, Uppsala, SE-750 07, Uppsala, Sweden.
    Assessing positive emotional states in dogs using heart rate and heartrate variability2016Ingår i: Physiology and Behavior, ISSN 0031-9384, E-ISSN 1873-507X, Vol. 155, 102-111 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Since most animal species have been recognized as sentient beings, emotional state may be a good indicator ofwelfare in animals. The goal of this study was to manipulate the environment of nine beagle research dogs tohighlight physiological responses indicative of different emotional experiences. Stimuli were selected to be amore or a less positive food (meatball or food pellet) or social reward (familiar person or less familiar person).That all the stimuli were positive and of different reward value was confirmed in a runway motivation test.Dogs were tested individually while standing facing a display theatre where the different stimuli could beshown by lifting a shutter. The dogs approached and remained voluntarily in the test system. They were testedin four sessions (of 20 s each) for each of the four stimuli. A test session consisted of four presentation phases(1st exposure to stimulus, post exposure, 2nd exposure, and access to reward). Heart rate (HR) and heart ratevariability (HRV) responses were recorded during testing in the experimental room and also when lying restingin a quiet familiar room. A newmethod of ‘stitching’ short periods of HRV data together was used in the analysis.When testing different stimuli, no significant differenceswere observed in HR and LF:HF ratio (relative power inlow frequency (LF) and the high-frequency (HF) range), implying that the sympathetic tone was activated similarlyfor all the stimuli and may suggest that dogs were in a state of positive arousal. A decrease of HF was associatedwith the meatball stimulus compared to the food pellet and the reward phase (interacting with the personor eating the food) was associated with a decrease in HF and RMSSD (root mean square of successive differencesof inter-beat intervals) compared to the preceding phase (looking at the person or food). This suggests that parasympatheticdeactivation is associated with a more positive emotional state in the dog. A similar reduction in HFandRMSSDwas found in the test situation compared to the resting situation. This is congruentwith the expectedautonomic effects related to postural shift i.e. sympathetic activation and parasympathetic withdrawal, duringstanding versus lying, but it cannot explain the parasympathetic deactivation in response to the more positivestimuli since the dogs were always standing in the test situation.Wediscuss the systematic pattern of responses,which support that increased HRand LF:HF ratio are associatedwithemotional arousal, but add the newproposalthat a combined decrease inRMSSD and HFmay reflect a more positively valencedemotional state evenwhen anindividual is already in a positive psychological state.

  • 4830.
    Äng, Oscar
    et al.
    Linköpings universitet, Matematiska institutionen. Linköpings universitet, Tekniska fakulteten.
    Trygg, Alexander
    Linköpings universitet, Matematiska institutionen. Linköpings universitet, Tekniska fakulteten.
    Planering av stränggjutningsproduktion: En heruistisk metod2017Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Detta arbete syftar till att undersöka om det är möjligt att med en heuristisk metod skapa giltiga lösningar till ett problem vid planering av stränggjutningsproduktion på SSAB. Planeringsproblemet uppstår när stål av olika sorter ska gjutas under samma dag. Beroende på i vilken ordning olika kundordrar av stål gjuts uppstår spill av olika storlek. Detta spill ska minimeras och tidigare arbete har genomförts på detta problem och resulterat i en matematisk modell för att skapa lösningar till problemet. Det tar i praktiken lång tid att hitta bra lösningar med modellen och frågeställningen är om det går att göra detta med en heuristisk metod för att kunna generera bra lösningar snabbare.

    Med inspiration från Variable Neighbourhood Search, Simulated Annealing och tabusökning har heuristiker skapats, implementerats och utvärderats mot den matematiska modellen. En av heuristikerna presterar bättre än den matematiska modellen gör på 10 minuter. Matematiska modellens resultat efter 60 minuter körtid är bättre än den utvecklade heuristiken, men resultaten är nära varandra. Körtiden för heuristiken tar signifikant mindre tid än 10 minuter.

  • 4831.
    Åkerlind, Christina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska fakulteten. Swedish Defence Research Agency (FOI), Linköping .
    Arwin, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan.
    Jakobsson, Fredrik L.E.
    Linköpings universitet.
    Kariis, Hans
    Swedish Defence Research Agency (FOI), Linköping .
    Järrendahl, Kenneth
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska högskolan.
    Optical Properties and Switching of a Rose Bengal Derivativ2009Konferensbidrag (Refereegranskat)
  • 4832.
    Åkerlind, Christina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten. FOI, Linköping, Sweden.
    Fagerström, Jan
    FOI, Linköping, Sweden.
    Hallberg, Tomas
    FOI, Linköping, Sweden.
    Kariis, Hans
    FOI, Linköping, Sweden.
    Evaluation criteria for spectral design of camouflage2015Ingår i: Proc. SPIE 9653, Target and Background Signatures / [ed] Karin U. Stein; Ric H. M. A. Schleijpen, SPIE - International Society for Optical Engineering, 2015, Vol. 9653, Art.no: 9653-2- s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In development of visual (VIS) and infrared (IR) camouflage for signature management, the aim is the design of surface properties of an object to spectrally match or adapt to a background and thereby minimizing the contrast perceived by a threatening sensor. The so called 'ladder model" relates the requirements for task measure of effectiveness with surface structure properties through the steps signature effectiveness and object signature. It is intended to link materials properties via platform signature to military utility and vice versa. Spectral design of a surface intends to give it a desired wavelength dependent optical response to fit a specific application of interest. Six evaluation criteria were stated, with the aim to aid the process to put requirement on camouflage and for evaluation. The six criteria correspond to properties such as reflectance, gloss, emissivity, and degree of polarization as well as dynamic properties, and broadband or multispectral properties. These criteria have previously been exemplified on different kinds of materials and investigated separately. Anderson and Åkerlind further point out that the six criteria rarely were considered or described all together in one and same publication previously. The specific level of requirement of the different properties must be specified individually for each specific situation and environment to minimize the contrast between target and a background. The criteria or properties are not totally independent of one another. How they are correlated is part of the theme of this paper. However, prioritization has been made due to the limit of space. Therefore all of the interconnections between the six criteria will not be considered in the work of this report. The ladder step previous to digging into the different material composition possibilities and choice of suitable materials and structures (not covered here), includes the object signature and decision of what the spectral response should be, when intended for a specific environment. The chosen spectral response should give a low detection probability (DP). How detection probability connects to image analysis tools and implementation of the six criteria is part of this work.

  • 4833.
    Åklint, Richard
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Khan, Muhammad Farhan
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Multidimensional Visualization of News Articles2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Large data sets are difficult to visualize. For a human to find structures and understand the data, good visualization tools are required. In this project a technique will be developed that makes it possible for a user to look at complex data at different scales. This technique is obvious when viewing geographical data where zooming in and out gives a good feeling for the spatial relationships in map data or satellite images. However, for other types of data it is not obvious how much scaling should be done.

    In this project, an experimental application is developed that visualizes data in multiple dimensions from a large news article database. Using this experimental application, the user can select multiple keywords on different axis and then can create a visualization containing news articles with those keywords.

    The user is able to move around the visualization. If the camera is far away from the document icons then they are clustered using red coloured spheres. If the user moves the camera closer to the clusters they will pop up into single document icons. If the camera is very close to the document icons it is possible to read the news articles

  • 4834.
    Ålund, Oskar
    et al.
    Linköpings universitet, Matematiska institutionen, Beräkningsmatematik. Linköpings universitet, Tekniska fakulteten.
    Nordström, Jan
    Linköpings universitet, Matematiska institutionen, Beräkningsmatematik. Linköpings universitet, Tekniska fakulteten.
    A provably stable, non-iterative domain decomposition technique for the advection-diffusion equation2016Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We describe an efficient, non-iterative domain decomposition approach for the onedimensional advection–diffusion equation based on the Summation-by-Parts technique in both time and space. A fully discrete multidomain analogue of the continuous equation is formulated and a linear system consisting only of the solution components involved in the coupling between the subdomain interfaces is isolated. Once the coupling system is solved, the full solution is found by computing linear combinations of known vectors, weighted by the coupling components. Both stability and invertibility of the discrete scheme is proved using standard Summation-by-Parts procedures.

    In a numerical study we show that perfunctory implementations of monodomain Summation-by-Parts based time integration can be improved upon significantly. Using our proposed method we are able to reduce execution time and memory footprint by up to 80% and 95% respectively. Similar improvements in execution time is shown also when compared against explicit Runge–Kutta time integration.

  • 4835.
    Åslund, Andreas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Sigurdson, Christina J
    Institute of Neuropathology, Department of Pathology, Universitätsspital Zürich, Schmelzbergstrasse 12, CH-8091 Zürich, Switzerland.
    Klingstedt, Therése
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Grathwohl, Stefan
    Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, University of Tuebingen, D-72076 Tuebingen, Germany.
    Bolmont, Tristan
    Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, University of Tuebingen, D-72076 Tuebingen, Germany.
    Dickstein, Dara L
    Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, USA.
    Glimsdal, Eirik
    Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
    Prokop, Stefan
    Department of Neuropathology, Charité-Universitätsmedizin Berlin, D-13353 Berlin, Germany.
    Lindgren, Mikael
    Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Holtzman, David M
    Department of Neurology, Alzheimer’s Disease Research Center, Washington University, St. Louis, Missouri 63110, USA.
    Hof, Patrick R
    Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, USA.
    Heppner, Frank L
    Department of Neuropathology, Charité-Universitätsmedizin Berlin, D-13353 Berlin, Germany.
    Gandy, Samuel
    Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York 10029, USA.
    Jucker, Mathias
    Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, University of Tuebingen, D-72076 Tuebingen, Germany.
    Aguzzi, Adriano
    Institute of Neuropathology, Department of Pathology, Universitätsspital Zürich, Schmelzbergstrasse 12, CH-8091 Zürich, Switzerland.
    Hammarström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biokemi. Linköpings universitet, Tekniska högskolan.
    Nilsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Novel Pentameric Thiophene Derivatives for in Vitro and in Vivo Optical Imaging of a Plethora of Protein Aggregates in Cerebral Amyloidoses2009Ingår i: ACS CHEMICAL BIOLOGY, ISSN 1554-8929, Vol. 4, nr 8, 673-684 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Molecular probes for selective Identification of protein aggregates are important to advance our understanding of the molecular pathogenesis underlying cerebral amyloidoses. Here we report the chemical design of pentameric thiophene derivatives, denoted luminescent conjugated oligothiophenes (LCOs), which could be used for real-time visualization of cerebral protein aggregates in transgenic mouse models of neurodegenerative diseases by multiphoton microscopy. One of the LCOs, p-FTAA, could be utilized for ex vivo spectral assignment of distinct prion deposits from two, mouse-adapted prion strains. p-FTAA also revealed a transient soluble pre-fibrillar non-thioflavinophilic A beta-assemblies during in vitro fibrillation of A beta peptides. In brain tissue samples, A beta deposits and neurofibrillary tangles (NFTs) were readily identified by a strong fluorescence from p-FTAA and the LCO staining showed complete co-localliation with conventional antibodies (6E10 and AT8). In addition, a patchy islet-like staining of individual A beta plaque was unveiled by the anti-oligomer A11 antibody during co-staining with p-FTAA. The major hallmarks of Alzheimers disease, namely, A beta aggregates versus NFTs, could also be distinguished because of distinct emission spectra from p-FTAA. Overall, we demonstrate that LCOs can be utilized as powerful practical research tools for studying protein aggregation diseases and facilitate the study of amyloid origin, evolution and maturation, A beta-tau interactions, and pathogenesis both ex vivo and in vivo.

  • 4836.
    Åström, Freddie
    et al.
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska fakulteten.
    Felsberg, Michael
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska fakulteten.
    On the Choice of Tensor Estimation for Corner Detection, Optical Flow and Denoising2015Ingår i: COMPUTER VISION - ACCV 2014 WORKSHOPS, PT II / [ed] C.V. Jawahar and Shiguang Shan, Springer, 2015, Vol. 9009, 15 s.16-30 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Many image processing methods such as corner detection,optical flow and iterative enhancement make use of image tensors. Generally, these tensors are estimated using the structure tensor. In this work we show that the gradient energy tensor can be used as an alternativeto the structure tensor in several cases. We apply the gradient energy tensor to common image problem applications such as corner detection, optical flow and image enhancement. Our experimental results suggest that the gradient energy tensor enables real-time tensor-based image enhancement using the graphical processing unit (GPU) and we obtain 40% increase of frame rate without loss of image quality.

  • 4837.
    Åström, Freddie
    et al.
    Heidelberg University, Germany.
    Felsberg, Michael
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Baravdish, George
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Mapping-Based Image Diffusion2017Ingår i: Journal of Mathematical Imaging and Vision, ISSN 0924-9907, E-ISSN 1573-7683, Vol. 57, nr 3, 293-323 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, we introduce a novel tensor-based functional for targeted image enhancement and denoising. Via explicit regularization, our formulation incorporates application-dependent and contextual information using first principles. Few works in literature treat variational models that describe both application-dependent information and contextual knowledge of the denoising problem. We prove the existence of a minimizer and present results on tensor symmetry constraints, convexity, and geometric interpretation of the proposed functional. We show that our framework excels in applications where nonlinear functions are present such as in gamma correction and targeted value range filtering. We also study general denoising performance where we show comparable results to dedicated PDE-based state-of-the-art methods.

  • 4838.
    Åström, Freddie
    et al.
    Heidelberg Collaboratory for Image Processing Heidelberg University Heidelberg, Germany.
    Felsberg, Michael
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Scharr, Hanno
    BG-2: Plant Sciences Forschungszentrum Jülich 52425, Jülich, Germany.
    Adaptive sharpening of multimodal distributions2015Ingår i: Colour and Visual Computing Symposium (CVCS), 2015 / [ed] Marius Pedersen and Jean-Baptiste Thomas, IEEE , 2015, 1-4 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work we derive a novel framework rendering measured distributions into approximated distributions of their mean. This is achieved by exploiting constraints imposed by the Gauss-Markov theorem from estimation theory, being valid for mono-modal Gaussian distributions. It formulates the relation between the variance of measured samples and the so-called standard error, being the standard deviation of their mean. However, multi-modal distributions are present in numerous image processing scenarios, e.g. local gray value or color distributions at object edges, or orientation or displacement distributions at occlusion boundaries in motion estimation or stereo. Our method not only aims at estimating the modes of these distributions together with their standard error, but at describing the whole multi-modal distribution. We utilize the method of channel representation, a kind of soft histogram also known as population codes, to represent distributions in a non-parametric, generic fashion. Here we apply the proposed scheme to general mono- and multimodal Gaussian distributions to illustrate its effectiveness and compliance with the Gauss-Markov theorem.

  • 4839.
    Öberg, Elisabet
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Appelqvist, Hanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Nilsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Non-fused Phospholes as Fluorescent Probes for Imaging of Lipid Droplets in Living Cells2017Ingår i: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 5, 28Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Molecular tools for fluorescent imaging of specific compartments in cells are essential for understanding the function and activity of cells. Here, we report the synthesis of a series of pyridyl- and thienyl-substituted phospholes and the evaluation of these dyes for fluorescent imaging of cells. The thienyl-substituted phospholes proved to be successful for staining of cultured normal and malignant cells due to their fluorescent properties and low toxicity. Co-staining experiments demonstrated that these probes target lipid droplets, which are, lipid-storage organelles found in the cytosol of nearly all cell types. Our findings confirm that thienyl-substituted phospholes can be utilized as fluorescent tools for vital staining of cells, and we foresee that these fluorescent dyes might be used in studies to unravel the roles that lipid droplets play in cellular physiology and in diseases.

  • 4840.
    Öberg, Rebecka
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Carl Malmsten - furniture studies. Linköpings universitet, Tekniska fakulteten.
    Oasen i arbetsplatsen: Ett designförslag om hur en restorativ zon kan berika vår arbetsmiljö2015Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Oasen i arbetsplatsen är ett designförslag på hur en restorativ zon i våra arbetsmiljöer skulle kunna gestaltas. Oasen är en tillgänglig plats för daglig återhämtning. En källa som är kravlös, stimulerar och omhändertar våra sinnen. Många i arbete väntar på att de ska känna sig trötta innan de tar paus, men det behöver inte betyda att hjärnan inte är trött. Att utveckla en plats för återhämtning leder till mer genomtänkta beslut och mer energi i vårt dagliga arbete. I förslaget har tre produkter utvecklats: en pedestal för växter, en gungsoffa och skärmvägg.

    Idag finns det få etablerade zoner för återhämtning i våra arbetsplatser. Forskning visar att det effektivaste sättet att återhämta sig i arbete är inte sömn utan s.k. vaken vila. Vaken vila kan vara när vi låter blicken vila på något utan koppling till prestation. I den vakna vilan rensas och bearbetas undertryckta tankar, vilket vi får ny mental energi. Den miljö människan återhämtar sig som allra bäst är i naturen. Vi har lättare för återhämtning i naturen eftersom den innehåller många element vi upplever som positiva: det handlar om att naturen ställer färre krav på oss människor, vi blir fascinerade, naturen har en vidd och en läsbarhet vilket vi finner trygghet i.

    Inom landskapsarkitekturen finns en forskningsgren i miljöpsykologi där naturintryckens restorativa påverkan på människan studeras för att kunna utveckla ex, rehabiliteringsträdgårdar. Restorativa naturintyck i vår interiör är fortfarande ett oexploaterat område inom designforskning. Idag har vi börjat inse värdet av sådan typ av forskning, eftersom vår innemiljö betyder mycket för vårt välbefinnande. Ännu finns ingen metod för att kunna säkerställa och kvalificera den typ av restorativa effekter en sådan interiör skulle kunna ge. Därför kommer detta arbete fungera som ett bidrag till den diskussionen.

    I arbetet har jag tittat framförallt på tre forskare inom restorativa naturteorier: Rachel och Stephen Kaplan samt Roger S. Ulrich. I min undersökning har jag även frågat människor om deras tankar kring produkter och miljöer. I slutet av undersökningen finns en intervju med Madeleine Stjärne, inredningsarkitekt på Sweco. Hon arbetar med ett forskningsprojekt tillsammans med SLU som handlar om ”restorativa naturintryck i interiörer”. I slutet på rapporten har jag även tagit fram ett designförslag på en restorativzon i arbetsplatsen.

  • 4841.
    Ödling, Mattias
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    How Provider Value is Perceived in regards to Integrated Product Service Offerings and why: A case study2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    As companies grow larger and become more international, it is likely that it comes to a point where it would be cheaper to produce on site, or at least have distribution centers, rather than having a centralized production that requires long range shipping. As this occurs, there is a wide range of challenges that the company must face, however these challenges are by now well documented and while not to be underestimated and called “easy” it is nothing new as a wide range of companies have done it before. One aspect that however is less known is the influence that external differences has, in other words factors that would produce a differing result even with the exact same internal setup, on the perceived aspects (referred to as Values in this work) from the providers point of view. In particular what is interesting is the perceived positive impacts above expectations that is gained from having external differences. To be able to better understand and quantify this impact the term “Provider Value” has been created and is being researched towards understanding what Values exist and how they are being affected.Provider Value (PV) is a cutting edge concept within eco-design research that this work is based on and in particular ProVa – Provider Value Evaluation for Integrated Product Service Offerings (Matschewsky et al. 2015) is the latest step to date towards creating the tools needed to increase the utilization, and reap the benefits, of PVs. Another interesting and relevant aspect to PV is how Product/Service System (PSS) could be an essential part in paving a new way of avoiding increased environmental impact while having economic growth. This is done by adding services on top of already existing products (Sakao et al. 2009).To find out more about what kind of external factors that might be behind the differences a case study was conducted, interviewing employees at two companies within one concern in Sweden and Japan. The results of this work indicates that if the company want its PVs to remain the same the main obstacle is external economic differences. In this particular study it is also clear that differences in business model and company structure has a big impact. With all the discussion regarding environment it was on a surprisingly low level of interest at both companies and what mattered was that the products cleared the minimum requirements, nothing more, as “any additional return is hard to estimate”. If PV keeps growing and tools are made to assist, this could not only help simplify the transitioning to other countries and help utilizing existing Values from the start, it could also increase the utilization in general, in particularly in regards to the Environment.

  • 4842.
    Ödling, Sara
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Is there a correlation between the nutrient content and variation in the HvNAM-2 gene in Hordeum vulgare?2015Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Barley is one of the most important cereal crops in the world and a better understanding of the factors that regulates the nutrient content in the grain is of high interest. The industrial breeding during the last century has led to bigger yield but possibly a decrease in nutrient content. In wheat, the NAM-B1 gene is a well-studied gene that affects the grain protein and micronutrient content. Two orthologue genes in barley HvNAM-1 and HvNAM-2 are candidate genes to play a similar role in the barley senescence process.

    I have looked for a correlation between the diversity in the HvNAM-2 gene and nutrient content in 37 Nordic barley accessions. The samples were sequenced and then aligned and analyzed for variation. I found three haplotypes which were compared in nutrient content and in micronutrient content. No significant difference between the haplotypes was found, which can be due to small sample size or that no correlation exists between the grain protein content and the HvNAM-2 gene variation. Significant correlation was however found between the nitrogen content and the micronutrient contents that indicate that the pathways of all the nutrients’ mobilizations are tightly coupled. For future research a bigger number of accessions, preferably at least 100, need to be analyzed to be able to give any conclusions. The molecular mechanisms in the cells during senescence also need further investigation.

  • 4843.
    Öfjäll, Kristoffer
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Adaptive Supervision Online Learning for Vision Based Autonomous Systems2016Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Driver assistance systems in modern cars now show clear steps towards autonomous driving and improvements are presented in a steady pace. The total number of sensors has also decreased from the vehicles of the initial DARPA challenge, more resembling a pile of sensors with a car underneath. Still, anyone driving a tele-operated toy using a video link is a demonstration that a single camera provides enough information about the surronding world.  

    Most lane assist systems are developed for highway use and depend on visible lane markers. However, lane markers may not be visible due to snow or wear, and there are roads without lane markers. With a slightly different approach, autonomous road following can be obtained on almost any kind of road. Using realtime online machine learning, a human driver can demonstrate driving on a road type unknown to the system and after some training, the system can seamlessly take over. The demonstrator system presented in this work has shown capability of learning to follow different types of roads as well as learning to follow a person. The system is based solely on vision, mapping camera images directly to control signals.  

    Such systems need the ability to handle multiple-hypothesis outputs as there may be several plausible options in similar situations. If there is an obstacle in the middle of the road, the obstacle can be avoided by going on either side. However the average action, going straight ahead, is not a viable option. Similarly, at an intersection, the system should follow one road, not the average of all roads.  

    To this end, an online machine learning framework is presented where inputs and outputs are represented using the channel representation. The learning system is structurally simple and computationally light, based on neuropsychological ideas presented by Donald Hebb over 60 years ago. Nonetheless the system has shown a cabability to learn advanced tasks. Furthermore, the structure of the system permits a statistical interpretation where a non-parametric representation of the joint distribution of input and output is generated. Prediction generates the conditional distribution of the output, given the input.  

    The statistical interpretation motivates the introduction of priors. In cases with multiple options, such as at intersections, a prior can select one mode in the multimodal distribution of possible actions. In addition to the ability to learn from demonstration, a possibility for immediate reinforcement feedback is presented. This allows for a system where the teacher can choose the most appropriate way of training the system, at any time and at her own discretion.  

    The theoretical contributions include a deeper analysis of the channel representation. A geometrical analysis illustrates the cause of decoding bias commonly present in neurologically inspired representations, and measures to counteract it. Confidence values are analyzed and interpreted as evidence and coherence. Further, the use of the truncated cosine basis function is motivated.  

    Finally, a selection of applications is presented, such as autonomous road following by online learning and head pose estimation. A method founded on the same basic principles is used for visual tracking, where the probabilistic representation of target pixel values allows for changes in target appearance.

  • 4844.
    Öfjäll, Kristoffer
    et al.
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Felsberg, Michael
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Online learning of autonomous driving using channel representations of multi-modal joint distributions2015Ingår i: Proceedings of SSBA, Swedish Symposium on Image Analysis, 2015, Swedish Society for automated image analysis , 2015Konferensbidrag (Övrigt vetenskapligt)
  • 4845.
    Öfjäll, Kristoffer
    et al.
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Felsberg, Michael
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Robinson, Andreas
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Visual Autonomous Road Following by Symbiotic Online Learning2016Ingår i: Intelligent Vehicles Symposium (IV), 2016 IEEE, 2016, 136-143 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recent years have shown great progress in driving assistance systems, approaching autonomous driving step by step. Many approaches rely on lane markers however, which limits the system to larger paved roads and poses problems during winter. In this work we explore an alternative approach to visual road following based on online learning. The system learns the current visual appearance of the road while the vehicle is operated by a human. When driving onto a new type of road, the human driver will drive for a minute while the system learns. After training, the human driver can let go of the controls. The present work proposes a novel approach to online perception-action learning for the specific problem of road following, which makes interchangeably use of supervised learning (by demonstration), instantaneous reinforcement learning, and unsupervised learning (self-reinforcement learning). The proposed method, symbiotic online learning of associations and regression (SOLAR), extends previous work on qHebb-learning in three ways: priors are introduced to enforce mode selection and to drive learning towards particular goals, the qHebb-learning methods is complemented with a reinforcement variant, and a self-assessment method based on predictive coding is proposed. The SOLAR algorithm is compared to qHebb-learning and deep learning for the task of road following, implemented on a model RC-car. The system demonstrates an ability to learn to follow paved and gravel roads outdoors. Further, the system is evaluated in a controlled indoor environment which provides quantifiable results. The experiments show that the SOLAR algorithm results in autonomous capabilities that go beyond those of existing methods with respect to speed, accuracy, and functionality. 

  • 4846.
    Öhlin, Andreas
    Linköpings universitet, Institutionen för systemteknik, Datorteknik. Linköpings universitet, Tekniska fakulteten.
    Real-Time Multi-Dimensional Fast Fourier Transforms on FPGAs2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Den här uppsatsen presenterar ett sätt att utföra multidimensionell fouriertransformi en omgivning med kontinuerligt flödande sample genom att beräkna transformenav varje dimension för sig i en pipeline. Resultatet är en tredimensionellpipelinad fouriertransform som är implementerad på en Stratix III FPGA. Dennaklarar av att beräkna fouriertransformen av en indatastorlek på 2563 samplersom är 32 bitar breda. Den största utmaningen och centrala delen av designen ärdatapermutation, denna del använder sig av DDR2 SDRAM och inbyggda BRAMför att spara och permutera data mellan de endimensionella transformmodulerna.Utvärderingen visar att designen är hårdvarueffektiv och att fördröjningen ärrelativt låg och ligger på 84.2 ms.

  • 4847.
    Öhlund, Elinor
    et al.
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Wang, William
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Phung, Gullis
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Olsson, Jonas
    Lundqvist, Felix
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Hultberg, Dag
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Fixcher, Max
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Back, Hampus
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska fakulteten.
    Design och implementation av en e-butik med en personifierbar produkt för att uppnå nytta och effektivitet: Utveckling av e-butiken Coffe Creation2017Självständigt arbete på grundnivå (kandidatexamen), 12 poäng / 18 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Syftet med den här studien är att finna faktorer som gör en e-butik med personifierbara produkter användbar i form av effektivitet och nytta. Processen fram till slutprodukten har gjorts med en iterationsbaserad user-centered design-metod där utvecklarna under arbetets gång har haft en kontinuerlig dialog med slutanvändaren. Designmässiga val har gjorts utifrån återkoppling från användartester vilket har resulterat i en slutsats om att det finns fem faktorer som är viktiga att ha i åtanke då en e-butik för personifierbara produkter ska utvecklas. Att applikationens syfte och funktion presenteras för användaren visade sig vara viktigt för såväl nytta som effektivitet. Användarens förståelse om hur ett val som tas i applikationen kommer att påverka produkten är kopplat till nytta, och applikationens återkoppling kring ett val som har gjorts är kopplat till effektivitet. En väl utarbetad hierarki för det flöde användaren går igenom vid anpassning av en personifierad produkt är en kritisk faktor för effektivitet. Den sista faktorn är relaterad till ett begrepp som har benämnts alternativa köpflöden. Detta handlar främst om att det kan finnas en användarnytta med att utgå från förinställda produkter vid anpassning, istället för att skapa en ny produkt från grunden.

  • 4848.
    Örn, Daniel
    et al.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Szilassy, Martin
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Dil, Bram
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Gustafsson, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    A Novel Multi-Step Algorithm for Low-Energy Positioning Using GPS2016Ingår i: Fusion 2016, 19th International Conference on Information Fusion: Proceedings, 2016, 1469-1476 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    GPS is widely used for localization and tracking, however traditional GPS receivers consume too much energy for many applications. This paper implements and evaluates the performance of a low-energy GPS prototype. The main difference is that a traditional GPS needs to sample signals transmitted by satellites for 30 seconds to estimate its position. Our prototype reduces this time by three orders of magnitude and it can compute positions from only 2 milliseconds of data. We present a new algorithm that increases robustness by filtering on estimated residuals instead of using an altitude database. In addition, we show that our new algorithm works with both fixed and moving targets. The solution consists of (1) a portable device that samples the GPS signal and (2) a server that utilizes Doppler navigation and Coarse Time Navigation to estimate positions. We performed tests in a wide variety of environments and situations. These tests show that our prototype provides a median positioning error of roughly 40 meters even when the GPS receiver is moving at 80 kilometres per hour.

  • 4849.
    Örtenberg, Alexander
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Parallelization of DIRA and CTmod Using OpenMP and OpenCL2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Parallelization is the answer to the ever-growing demands of computing power by taking advantage of multi-core processor technology and modern many-core graphics compute units. Multi-core CPUs and many-core GPUs have the potential to substantially reduce the execution time of a program but it is often a challenging task to ensure that all available hardware is utilized. OpenMP and OpenCL are two parallel programming frameworks that have been developed to allow programmers to focus on high-level parallelism rather than dealing with low-level thread creation and management. This thesis applies these frameworks to the area of computed tomography by parallelizing the image reconstruction algorithm DIRA and the photon transport simulation toolkit CTmod. DIRA is a model-based iterative reconstruction algorithm in dual-energy computed tomography, which has the potential to improve the accuracy of dose planning in radiation therapy. CTmod is a toolkit for simulating primary and scatter projections in computed tomography to optimize scanner design and image reconstruction algorithms. The results presented in this thesis show that parallelization combined with computational optimization substantially decreased execution times of these codes. For DIRA the execution time was reduced from two minutes to just eight seconds when using four iterations and a 16-core CPU so a speedup of 15 was achieved. CTmod produced similar results with a speedup of 14 when using a 16-core CPU. The results also showed that for these particular problems GPU computing was not the best solution.

  • 4850.
    Örtenberg, Alexander
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Medicinska fakulteten.
    Magnusson, Maria
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Medicinska fakulteten.
    Sandborg, Michael
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Alm Carlsson, Gudrun
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Malusek, Alexandr
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten.
    PARALLELISATION OF THE MODEL-BASED ITERATIVE RECONSTRUCTION ALGORITHM DIRA2016Ingår i: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 169, nr 1-4, 405-409 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New paradigms for parallel programming have been devised to simplify software development on multi-core processors and many-core graphical processing units (GPU). Despite their obvious benefits, the parallelisation of existing computer programs is not an easy task. In this work, the use of the Open Multiprocessing (OpenMP) and Open Computing Language (OpenCL) frameworks is considered for the parallelisation of the model-based iterative reconstruction algorithm DIRA with the aim to significantly shorten the code’s execution time. Selected routines were parallelised using OpenMP and OpenCL libraries; some routines were converted from MATLAB to C and optimised. Parallelisation of the code with the OpenMP was easy and resulted in an overall speedup of 15 on a 16-core computer. Parallelisation with OpenCL was more difficult owing to differences between the central processing unit and GPU architectures. The resulting speedup was substantially lower than the theoretical peak performance of the GPU; the cause was explained.

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