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941.
942.
943.
S. K. Liu L. Yang D. G. Zhu J. Zhang 《Metallurgical and Materials Transactions A》1994,25(9):1991-2000
A series of Fe-C-X and Fe-C-X1-X2 alloys in which X, X1 and X2 either raise or depress the activity of C iny were investigated by autodilatometer, optical microscopy, and transmission electron microscopy (TEM) to reveal the relations
among the chemical composition, transformation kinetics, and morphology of ferrite plates. The incubation time of austenite
decomposition at the nose temperature in the time-temperature-transformation (TTT) diagrams, the concentration of C in y in
contact with theα/gg boundary, and the growth rate of ferrite were evaluated to estimate the magnitude of the solute drag-like
effect (SDLE) for the different alloying elements used. All the results are consistent qualitatively with the SDLE hypothesis.
This article is based on a presentation made at the Pacific Rim Conference on the “Roles of Shear and Diffusion in the Formation
of Plate-Shaped Transformation Products,” held December 18-22, 1992, in Kona, Hawaii, under the auspices of ASM INTERNATIONAL’S
Phase Transformations Committee. 相似文献
944.
论述了平板玻璃包装技术改进对提高包装质量和企业经济效益的影响,介绍了平板玻璃包装箱(架)的性能,简述了计算机辅助设计及计算机辅助管理在玻璃包装结构设计及包装质量管理中的效用。 相似文献
945.
本文介绍核孔膜生产线,重点描述了膜微孔制备工艺的实验研究。对于PC和PES膜,已得到32种工况下的扩孔公式,其形式为D=A+Bt,其中D——孔径,t——扩孔时间,A,B为特定工艺参数下的常数值.通过实验。得到了膜孔密度N与300~#核反应堆功率P、热柱辐照位置L的经验公式,即N=6.97×10~5×10~3×101~(1.18L).在本生产线上可生产最大幅面为3 140mm×240mm,孔径为0.04~10 μm的多系列多规格的核孔膜产品。 相似文献
946.
Pleiotrophin (PTN) is a heparin-binding cytokine that functions as a neurite outgrowth promoting and mitogenic activity in vitro. PTN is highly conserved and its gene is widely expressed in mammalian tissues during development, suggesting important roles of PTN in vivo. However, the mechanisms by which PTN mediates its functional activities are unknown. We now report that an approximately 200 kDa (p200) protein is phosphorylated (pp200) in PTN stimulated NIH 3T3 and NB41A3 cells five minutes after stimulation with PTN. Phosphorylation is maximum at 15 minutes and is PTN concentration dependent. pp200 is recognized by antiphosphotyrosine antibodies and contains both phosphotyrosine and phosphoserine by phosphoamino acid analysis. The results suggest that PTN functions in part through activation of protein kinase(s) in NIH 3T3 and NB41A3 cells. 相似文献
947.
A finite element (FE) based formulation is utilized to represent the damage-dependent response of laminated composite structures. An internal-state-variable (ISV) approach provides a definition of the stiffness reduction caused by intralaminar crack propagation at the ply level. These ISVs are combined with simple stress criteria to accommodate ply property changes caused by fiber fracture, fiber microbuckling and interior delaminations. A set of orthogonal Ritz vectors are chosen as basis vectors to transform the dynamical equations of motion to a reduced coordinate space. The reduced basis form of the equations provides significant numerical efficiencies, especially for large ordered systems. Furthermore, damping and its variation with damage can be generally represented in any number of vibratory modes. The Newmark integration operator is used to solve the dynamic equations of motion, and equilibrium iterations are performed in each incremental time step to assure convergence. Results are given for laminated beam and plate geometries subjected to dynamic loads. 相似文献
948.
多媒体音频设备驱动程序的结构和原理 总被引:4,自引:2,他引:2
李国辉 《小型微型计算机系统》1994,15(5):8-12
本文以波形音频输入输出为样本,剖析了Windows音频设备驱动程序的结构和原理。Windows设备驱动程序为应用提供了可扩展,设备无关,一致的接口。本文给出了数字波形数据I/O的处理过程,以及应用程序,驱动程序和音频硬件的层次关系。 相似文献
949.
Responses of cytotoxic T-cells (Tc) to human cytomegalovirus (CMV) represent the predominant mechanism by which hosts resist CMV infection. The CMV major immediate-early protein (IE) is present throughout the virus replicative cycle. Studies were performed to determine whether Tc specific for IE effectively lyse CMV-infected targets and are thus capable of providing protective immunity against infection. After in vitro stimulation of peripheral blood mononuclear cells with CMV-infected autologous fibroblasts, Tc specific for IE were not readily detectable in CMV-reactive polyclonal Tc lines. However, after stimulation of peripheral blood mononuclear cells with cells selectively expressing IE, weak but detectable IE-specific Tc responses were observed. The frequency of IE-specific Tc clones derived from cultures stimulated with IE-expressing cells was 50 to 100 times lower than the frequency of Tc clones specific for other CMV proteins isolated from cultures stimulated with CMV-infected cells. All of the IE-specific Tc clones, which efficiently lysed targets selectively expressing IE, demonstrated minimal lysis of CMV-infected fibroblasts, despite abundant IE expression in these target cells. In contrast to these results with IE, other viral proteins were efficiently presented during all phases of CMV infection. These data suggest that CMV has evolved a unique mechanism for selectively limiting the presentation of the potentially immunogenic IE protein, which may preclude IE-specific Tc from providing protective immunity to CMV infection. 相似文献
950.
StudyonFactorsAffectingtheStructureofHighSpeedSteelIngotProducedbyESRLiZhengbang;CheXiangqianAbstract:Theinfluenceofthemetalp... 相似文献