Unification of viscose models for powder suspension system

The viscose models for powder suspension system was reviewed and analysed.It is found that by introducing modification function f(φ）in the differential form of classical Einstein‘s viscosity law,all of viscose models can be unified if f(φ） takes suitable form,Some rational forms of the function f(φ） were discussed according to functional approximation method,and a new rheological model contained two undetermined parameters was consequently developed,more suitable for high partical concentration dispersing system,The experimental results show that this new model is of better consistence.     

金属注射成形中的高技术,新概念

较系统地阐述和分析了金属注射成形粉末冶金学科中的发展过程，特别是近年来在这一领域中出现的高技术、新概念，对其产生发展的背景和主要技术特点作了较全面的分析。     

超硬无机材料纳米粉末CVD合成热力学分析

通过热力学分析研究了超硬无机材料，如ＳｉＣ、Ｓｉ３Ｎ４、ＴｉＣ、ＴｉＮ等纳米粉末的化学气相沉积（ＣＶＤ）合成反应过程和核化过程的有关热力学规律。结果表明：合成物以共价键和以金属键为主的合成反应和化学反应过程对温度、压力均比较敏感，热力学驱动力随温度变化增加比较明显，对外压的敏感表现为增大压力对合成反应不利。合成物以离子键为主时，反应的热力学驱动力随温度变化不明显，外压的影响也不显著。对于核化过程，合成物以金属键和离子键为主的体系，核化所需临界过饱和度较低，ｌｇ（ｐ／ｐ０）在１～１０之间，而对合成物以共价键为主的体系，核化所需过饱和度较高，ｌｇ（ｐ／ｐ０）约在１５～２０之间，因实验过程很难达到这样高的过饱和度，因此合成粉体常以非晶态形式存在，以降低核化阻力     

碱性铝电池用合金阳极研究进展

从铝电池合金阳极的活化机理,合金元素（稀土金属）,热处理工艺以及缓蚀剂等方面,综述了国内外铝电池合金阳极的发展情况,并指出了铝阳极电池的发展方向。     

微型燃料电池充电器

燃料电池技术在20世纪90年代开始进入实用开发阶段,最早推出产品的是微型燃料电池充电器。在5 a时间内,先后有若干款微型燃料电池充电器产品进入市场,虽然销量不如锂离子电池产品,但有更高的能量密度及更长的使用寿命。     

氮掺杂碳纳米纤维包覆超细碳化钼/氮化钼异质结构用于碱性条件下电催化析氢

高效非贵金属催化剂对于推进析氢反应(HER)的大规模工业化至关重要.碳化钼(Mo₂C)因其类似铂的能带密度和优良的中间产物吸附特性,有望替代贵金属基材料成为具有前景的催化剂.然而,它在常规制备过程中存在严重的晶体过度生长和团聚问题,导致催化效率低.本研究利用三聚氰胺辅助法制备了含有丰富表面和界面的超细碳化钼/氮化钼(Mo₂C/Mo₂N)异质结构,并同时将其嵌入到氮掺杂碳纳米纤维(CNFs)中.Mo₂C/Mo₂N异质结构的协同作用与超细纳米晶表面暴露的丰富活性位点共同提高了电催化活性,而氮掺杂碳纳米纤维框架保证了快速的电荷转移和良好的结构稳定性.此外,原位形成的Mo₂C/Mo₂N晶体与碳基质之间存在较强的界面耦合作用,进一步提高了电子电导率和电催化活性.得益于这些优势,Mo₂C/Mo₂N@N-CNFs在碱性溶液中表现出优异的电催化析氢性能,在电流密度10 mV cm^-2时具有75 mV的低过电势,优于单相Mo₂C@N-CNFs对比样以及近期报道的Mo₂C/Mo₂N基催化剂.这个合成方法集成了异质结构、纳米化和碳修饰策略,为设计高效率电催化材料提供了新的参考.     

Structure and mechanical properties of ZrO2-mullite nano-ceramics in SiO2-Al2O3-ZrO2 system

ZrO2-mullite nano-ceramics were fabricated by in-situ controlled crystallizing from SiO2-Al2O3-ZrO2 amorphous bulk. The thermal transformation sequences of the SiO2-Al2O3-ZrO2 amorphous bulk were investigated by X-ray diffraction, infrared spectrum, scanning electron microscope and differential scanning calorimetric. And the mechanical properties of the nano-ceramics were studied. The results show that the bulks are still in amorphous state at 900 ℃ and the t-ZrO2 forms at about 950 ℃ with a faint spinel-like phase which changes into mullite on further heating. ZrO2 and mullite become major phases at 1 100 ℃ and an amount of m-ZrO2 occur at the same time. The sample heated at 950 ℃ for 2 h and then at 1 100 ℃ for 1 h shows very dense and homogenous microstructure with ball-like grains in size of 20-50 nm. With the increase of crystallization temperature up to 1 350 ℃, the grains grow quickly and some grow into lath-shaped grains with major diameter of 5 μm. After two-step treatment the highest micro-hardness, flexural strength and fracture toughness of the samples are 13.72 GPa, 520 MPa and 5.13 MPa·m1/2, respectively.     

New development of Einstein＇s viscose law for powder suspension systems

Through the analysis of the present situation of the rheology of suspension disperse systems, the classical Einstein‘s viscosity law was developed into the generalized Einstein‘s viscosity law which can be further developed into universalized form, called the universalized Einstein‘s viscosity law by introducing modification function f(φ). Some rational forms of the function f(φ) were discussed according to functional approximation method, and were consequently developed into a few suspension disperse system rheological equations suitable for high particle concentration. These equations all keep good consistence with the models acquired in experiments or other mathematical physics analysis.     

铝合金阳极性能影响因素的研究进展

在铝合金阳极的活化机理的基础上,探讨了合金元素(稀土金属)、热处理、轧制工艺以及缓蚀剂等方面对铝阳极性能的影响,综述了国内外铝合金阳极的发展情况,并指出了铝阳极材料的发展方向和前景.