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991.
Jianfeng Gao Xiangjun Xu Junpin Lin Xiping Song Yanli Wang Guoliang Chen 《北京科技大学学报(英文版)》2005,12(6):535-539
The effect of strain rate on the yield strength of high Nb containing TiAl alloy was studied. The results show that the strain rate sensitivity varies with the test temperature, and the yield strength is not sensitive to the strain rate at room temperature but significantly sensitive to the strain rate at high temperature. An increase of the strain rate or a decrease of the temperature results in an obvious change of fracture mode. It is found that the strain rate sensitivity of this alloy varying with temperature is due to the dislocation climb generated at high temperature. 相似文献
992.
Guiying Xu Yanping Gao Changchun Ge Weiping Shen 《北京科技大学学报(英文版)》2005,12(4):347-350
The p-type (Bi0.15Sb0.85)2Te3 and PbTe are typical thermoelectric materials used for low and middle temperature range and functional graded materials (FGM) is an inevitable way to widen the working temperature range. Here two segments graded thermoelectric materials (GTM) consisting of (Bi0.15Sb0.85)2Te3, PbTe and different barriers were fabricated by the common hot pressure method. Metals Fe, Mg and Ni were used as barriers between the two segments. The diffusion of different barriers between the barriers and bases were analyzed by electron microprobe analysis (EMA). The phase and crystal structures were determined by X-ray diffraction analysis (XRD). The thermoelectric properties were measured at 303 K along the direction parallel to the pressing direction. The results show that the compositional diffusion occurs when there is no barrier at the interface of the two segments, and the diffusion of Pb is most obvious; as the barrier material, the diffusion of metals Fe, Mg and Ni between different bases is not very obvious, and the thermoelectric properties of GTM is much better than that of the original segment. 相似文献
993.
994.
Evaluating Acceleration Ability of Electrons of SiO_2 and ZnS in ZnS∶Er Electroluminescence 总被引:1,自引:0,他引:1
SinceCoeyandSun[1]discoveredtheinterstitial compoundSm2Fe17Nx,ithasattractedmanyresearch ers′attention.Asakindofpermanentmagneticmate rial,Sm2Fe17Nxexhibitsfairlyhighsaturationmagneti zation(1.54T)[2],highanisotropyfield(14T)under roomtemperatureandhighC… 相似文献
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997.
尽管连续铸钢技术已经在全世界广泛、成功地应用,然而通过现存所选择的工艺和设计参数来生产高质量产品还有一些障碍。近年来,通过冶金工作者的不断努力,取得了一些突破性成就。 相似文献
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1000.
A refined beam theory based on the refined plate theory 总被引:5,自引:0,他引:5
Summary Based on the refined plate theory, a refined theory of rectangular beams is derived by using the Papkovich-Neuber solution and Lur’e method without ad hoc assumptions. It is shown that the displacements and stresses of the beam can be represented by the angle of rotation and the deflection of the neutral surface. The solutions based on the new theory are the same as the exact solutions of elasticity theory. In three examples it is shown that the new theory provides as good or better results than Levinson’s beam theory when compared to those obtained from the linear theory of elasticity. 相似文献