Sökning: "s peng"

Hittade 4 avhandlingar innehållade orden s peng.

  1. 1. Modelling and Simulation of Reactor Pressure Vessel Failure during Severe Accidents

    Författare :Peng Yu; Weimin Ma; Walter Villanueva; Sevostian Bechta; Florian Fichot; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; RPV failure; thermo-fluid-structure coupling; creep modelling; melt pool heat transfer; severe accident; CFD; FEA; transIVR;

    Sammanfattning : This thesis aims at the development of new coupling approaches and new models for the thermo-fluid-structure coupling problem of reactor pressure vessel (RPV) failure during severe accidents and related physical phenomena. The thesis work consists of five parts: (i) development of a three-stage creep model for RPV steel 16MND5, (ii) development of a thermo-fluid-structure coupling approach for RPV failure analysis, (iii) performance comparison of the new approach that uses volume loads mapping (VLM) for data transfer with the previous approach that uses surface loads mapping (SLM), (iv) development of a lumped-parameter code for quick estimate of transient melt pool heat transfer, and (v) development of a hybrid coupling approach for efficient analysis of RPV failure. LÄS MER

  3. 2. Spark Plasma Sintering of Si3N4-based Ceramics : Sintering mechanism-Tailoring microstructure-Evaluationg properties

    Författare :Hong Peng; Zhijian (James) Shen; Mats Nygren; Michael J. Hoffmann; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spark plasma sintering; silicon nitride ceramics; grain growth kinetic; superplasiticity; liqiud phase sintering; Chemistry; Kemi;

    Sammanfattning : Spark Plasma Sintering (SPS) is a promising rapid consolidation technique that allows a better understanding and manipulating of sintering kinetics and therefore makes it possible to obtain Si3N4-based ceramics with tailored microstructures, consisting of grains with either equiaxed or elongated morphology. The presence of an extra liquid phase is necessary for forming tough interlocking microstructures in Yb/Y-stabilised α-sialon by HP. LÄS MER

  4. 3. Function of wobble nucleoside modifications in tRNAs of Salmonella enterica Serovar Typhimurium

    Författare :Peng Chen; Glenn R. Björk; Paul Agris; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Molecular biology; tRNA; wobble nucleoside; frameshifting; translation; Molekylärbiologi; Molecular biology; Molekylärbiologi; molekylärbiologi; Molecular Biology;

    Sammanfattning : Transfer RNA from all organisms has modified nucleosides and position 34 (the wobble position) is one of the most extensively modified positions. Some wobble nucleoside modifications restrict codon choice (e.g. 5-methylaminomethyl-2-thiouridine, mnm5s2U) while some extend the decoding capacity (e. LÄS MER

  5. 4. Architecture and function of the insulin granule secretion machinery

    Författare :Peng Yin; Sebastian Barg; Herbert Gaisano; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Docking; Syntaxin-1A; Voltage-gated Ca2 Channels; Exocytosis; Type-2 Diabetes;

    Sammanfattning : Insulin is released into the blood stream to normalize elevated blood glucose, for example after a meal. The hormone is synthesized by β-cells in the endocrine pancreas, and stored in small vesicles, known as secretory granules, until required. When glucose is elevated, these granules undergo regulated exocytosis and thereby secrete the hormone. LÄS MER