Search for dissertations about: "W. Wei"

Showing result 1 - 5 of 9 swedish dissertations containing the words W. Wei.

  2. 1. Ageing behavior of plastics used in automotive fuel systems

    Author : Xin-Feng Wei; Mikael S. Hedenqvist; Richard Olsson; Ulf W Gedde; Pieter Gijsman; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Automotive; Ageing; Polyamide; Diesel; Biodiesel; Diffusion; Oxidation; Plasticizer migration; Mechanical properties; Fracture behavior.; Fordon; Åldrande; Polyamid; Diesel; Biodiesel; Diffusion; Oxidation; Mjukgöraravgång; Mekaniska egenskaper; Brottegenskaper;

    Abstract : The increase in service temperature and the use of biobased fuels, such as biodiesel, have raised concerns on the short/long-term performance of plastic components used in automotive fuel systems.In this work the ageing behavior of unreinforced and glass-fibre reinforced polyamide 12 (PA12), exposed to three different fuels (petroleum diesel, biodiesel, and a mixture of these (80/20)) at high temperature, was investigated. READ MORE

  4. 2. Electro-thermal simulations and measurements of silicon carbide power transistors

    Author : Wei Liu; Carl-Mikael Zetterling; Nicholas G. Wright; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electronics; silicon carbide; power device; metal semiconductor field-effect transistor; bipolar junction transistor; electro-thermal simulation; Elektronik; Electronics; Elektronik;

    Abstract : The temperature dependent electrical characteristics of silicon carbide power transistors – 4H-SiC metal semiconductor field-effect transistors (MESFETs) and 4H-SiC bipolar junction transistors (BJTs) have been investigated through simulation and experimental approaches. Junction temperatures and temperature distributions in devices under large power densities have been estimated. READ MORE

  5. 3. Regeneration in the adult brain after focal cerebral ischemia : exploration of neurogenesis and angiogenesis

    Author : Wei Jiang; Jukka Jolkkonen; Umeå universitet; []
    Keywords : LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; neurogenesis; angiogenesis; rats; mice; gliosis; BrdU; CBF; protein synthesis; ATP; penumbra; reperfusion; VEGF; 3-D confocal; photothrombosis; MCAO; Medicine; Medicin;

    Abstract : Background: Ischemic stroke ranks as the third major cause of clinical mortality and the leading cause of handicap in adults. Each year, stroke occurs in about 30,000 Swedes. The severity of an acute ischemic stroke depends mainly on the degree and duration of local cerebral blood flow (lCBF) reduction. READ MORE

  6. 4. Effect of metal ion irradiation on hard coating synthesis by physical vapor deposition

    Author : Tun-Wei Hsu; Magnus Odén; Grzegorz Greczynski; Sven Ulrich; Linköpings universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : The aim of this thesis is to understand and control how the ions in the plasma influence the film growth during thin film deposition processes. Two physical vapor deposition (PVD) techniques are investigated, namely magnetron sputtering and cathodic arc evaporation. READ MORE

  7. 5. Toward Energy-efficient Physical Vapor Deposition : Routes for Replacing Substrate Heating during Magnetron Sputtering by Employing Metal Ion Irradiation

    Author : Xiao Li; Grzegorz Greczynski; Ivan Petrov; Lars Hultman; Jyh-Wei Lee; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; PVD; Magnetron sputtering; Thin films; HiPIMS; TiAlN; Energy efficiency;

    Abstract : In this Thesis, magnetron sputtering is perfected as an environmental-friendly deposition technique. I performed systematic studies of a novel approach - hybrid high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) with metal-ion-synchronized substrate bias pulses. READ MORE