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51.
总结了近年来本课题组在外加强化相非晶复合材料制备方面取得的主要研究结果。通过制备过程凝固控制获得了性能优异的非晶复合材料,其中金属W/Zr基非晶合金双连续相复合材料压缩强度达到3450MPa,压缩应变为48%;金属Ti/Mg基非晶合金双连续相复合材料压缩强度达到1750MPa,塑性应变为30%;8%Nb颗粒/Mg基非晶复合材料压缩强度达到900MPa,塑性应变为12.1%;6%SiC颗粒/Zr基非晶复合材料压缩强度达到2230MPa,塑性应变为3%。 相似文献
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Yang Wang Yu Sui Xianjie Wang Wenhui Su Xiaoyang Liu Hong Jin Fan 《Acta Materialia》2010,58(19):6306-6316
The thermal transport properties of a series of electron-doped CaMnO3 perovskites have been investigated. Throughout the temperature range 5–300 K, phonon thermal conductivity is dominant, and both electron and spin wave contributions are negligible. The short phonon mean free paths in this system result in the relatively low thermal conductivities. The strong phonon scatterings stem from the A-site mismatch and bond-length fluctuations induced by local distortions of MnO6 octahedra. The thermal conductivity in the magnetically ordered state is enhanced as a result of the decrease in spin–phonon scattering. The results also indicate that above the magnetic ordering temperature, observable thermal excitation of optical phonons occurs. The contribution of optical phonons to thermal conductivity becomes non-negligible and is proposed to play an important role in the glass-like thermal transport behavior (i.e. positive temperature dependence of the thermal conductivity) in the paramagnetic state. These features can be understood in terms of an expression of thermal conductivity that includes both acoustic and optical phonon terms. 相似文献
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The size effects on the charge ordering (CO) and magnetic properties in La0.25Ca0.75MnO3 with mean particle size ranging from 40 to 2000 nm were studied. With decreasing particle size the CO transition temperature shifts to lower temperature and the transition width becomes increasingly wide, indicating the weakening of the CO state. Meanwhile the ferromagnetic (FM) cluster glass state appears and the magnetization at low temperature increases significantly. The behaviour is due to the increasing uncompensated surface spins which weaken the antiferromagnetic interaction and disfavour the formation of the CO state. The suppression of the CO state and appearance of the FM cluster glass state are also found in La0.25Ca0.75MnO3 nanowires fabricated by a sol–gel template method. These results indicate that the CO state can be modulated effectively by varying particle size, which has an important implication for nano-device applications of manganites. 相似文献
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Cu2O/Cu nanocomposites (NCs) are synthesized using a two-step hydrothermal method, their different phase compositions are obtained by adjusting the reaction time, and then, they are used as photocatalysts to degrade dye Procion Red MX-5B (PR), methylene blue (MB) and methyl orange (MO) under visible-light. Experimental results indicate Cu2O/Cu NCs exhibit a much higher photocatalytic activity than pure Cu2O, they remain almost unchanged in their phase compositions in the long photocatalytic reaction process, except for partial oxidation of particle surface. They still exhibit a high photocatalytic activity even at the end of four photocatalytic reaction cycles. It can therefore be concluded that Cu2O/Cu nanocomposites are good candidates for processing of pollutant water. 相似文献
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The second part of this review of developments over the life span of electroless plating continues with the period of rapid development (1980–99), describing the upsurge of large scale application, research into ternary and multi-component alloys and composites, the rapid development in China – now the world’s biggest consumer of electroless Ni – and the development of electroless deposition of Fe–B based alloys. Since the new millennium began many fundamental mechanistic studies have been conducted and the development of nano-electroless plating has occurred. 相似文献
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桥面铺面防水粘结层胶结材料洒布量的确定方法 总被引:1,自引:1,他引:1
为确定桥面铺面防水粘结层胶结材料洒布量,采用橡胶沥青和两种典型的沥青混合料,通过设计直向剪切试验和斜向剪切试验研究桥面防水粘结层的力学性能,分析不同因素对于防水粘结层剪切性能的影响.试验结果表明,加载速率的提高,粘结层最大剪切应力有呈线性增大的趋势;采用不同温度的对比试验,同样发现随温度的升高,其抗剪切能力显著衰减.可以通过剪切试验的剪应力和变形能两个指标评价其剪切性能. 相似文献