铝锅蒸屉零件冲孔成形模设计与制造

该零件原采用先成形后冲孔两道加工工序,经对零件进行工艺分析后,改为冲孔成形一道加工工序.改进后的模具结构合理、效率高、产品零件稳定性可靠.     

CoSb3基Skutterudite化合物拉曼光谱研究

Skutterudite材料因具有特殊的晶体结构成为当前最有前途的热电材料之一,为深入研究填充Skutterudite化合物的热传导机制,对化合物的声子振动模式及置换、填充原子对声子模的影响进行了研究.通过对CoSb3,Co3.5Fe0.5Sb12的偏振拉曼谱研究,确认了一个Ag模,且与理论计算吻合较好.对CoSb3,Co3.5Fe0.5Sb12和La0.6Co3.5Fe0.5Sb12拉曼谱的对比研究表明,单纯Fe置换对拉曼谱影响很小,而La部分填充则使部分拉曼峰明显展宽,分析认为,这一现象主要源于填充原子在晶格空隙中的扰动.     

中南大学学科布局及结构调整研究

学科结构及布局关系到高等学校整体功能的发挥和全局的发展 ,它直接影响人才培养的质量、规格、类型 ,关系到科研与创新能力和水平 ,最终影响到学校发展目标的实现。本文根据中南大学“综合性研究型大学”的发展目标 ,就中南大学学科布局和结构调整进行了研究。     

变粘度条件下静压支承滑靴副的理论研究

本文对变粘度条件下的静压支承滑靴副进行了一定的理论研究和分析，通过计算机仿真，得出了滑靴副泄漏流量和支承反力不仅与中心油室压力有关，而且还与流体的粘温系数、粘压系数、密度和比热容等有关的结论，为高速高压轴向柱塞泵的设计提供了一定的理论依据。     

多轴精密数控电火花成形机的研制

从机床结构、脉冲电源系统、数控系统、精密分度轴等几方面介绍了采用引进消化吸收、再创新后的研究成果--多轴精密数控电火花成形机,并用典型的加工实验验证了该机床达到的技术水平和丰富的功能,为精密复杂模具和零件的电火花加工提供了良好的制作母机.     

超超临界锅炉用SA-335P92钢的焊接工艺性能研究

通过铁研试验及热模拟试验等对超超临界锅炉用SA-335P92钢的焊接性进行了研究.铁研试验表明,材料焊前钨极氩弧焊时预热温度≥150℃,焊条电弧焊和埋弧焊时预热温度≥200 ℃可以保证焊接不出现裂纹.通过焊缝粗晶区冲击试验,确定了合理的焊接热处理规范.进行了相应的使用焊接性试验,给出了SA-335P92材料的焊接工艺要点.     

碳化钨对常压烧结氮化硅陶瓷致密化的影响

研究碳化钨对常压烧结Si3N4-MgO－CeO2陶瓷致密化和性能的影响，通过球磨引入适量的碳化钨对烧结氮化硅陶瓷的致密化和性能是有利的，通过控制球磨时间和球料比可控制磨入的碳化钨的含量，当碳化钨含量为3．9wt％时，效果最好，烧结氮化硅陶瓷的相对密度为98．5％，室温抗弯强度为948MPa。     

模态分析技术及其在锻压工程中的应用前景

本文介绍了模态分析技术的概念、目的、内容和方法,论述了模态分析技术在锻压工程中的应用前景,以及它在建立锻压机械动态设计理论中的作用。     

Characterization of microstructure of Nano-TiO2 coating deposited by vacuum cold spraying

Control of the microstructure of TiO₂ coatings through preparation methods significantly influences the coating performance. In this study, a vacuum cold-spray process, as a new coating technology, is used to deposit nanocrystalline TiO₂ coatings on conducting glass and stainless steel substrates. TiO₂ deposits were formed using two types of nanocrystalline TiO₂ powders with mean particle diameters of 200 and 25 nm. Coating microstructures were characterized by scanning electron microscopy and x-ray diffraction analysis. Results demonstrate that a thick nanocrystalline TiO₂ coating can be deposited by the vacuum cold-spray process. The coating was found to consist of particles stacked as agglomerates that build up to several hundred nanometers. The coating also presents a mesoporous microstructure that could be effective in such applications as photocatalytic degradation and dye-sensitized solar cells. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

Facile regeneration vitreous microfibrous entrapped supported ZnO sorbent with high contacting efficiency for bulk H2S removal from reformate streams in fuel cell applications

In this study, a microfibrous carrier consisting of 3 vol.% of 8 μm (diameter) glass fibers is used to entrap 45 vol.% of 150 to 250 μm (diameter) SiO₂ support particulates. ZnO is then nanodispersed onto the support by impregnation at the loading of 17 wt.%. At equivalent bed volumes, ZnO/SiO₂-entrapped materials provide twofold longer breakthrough times for H₂S (with a 67% reduction in sorbent loading) compared with packed beds of 1 to 2 mm commercial extrudates. Five-log reductions in H₂S concentration with up to 75% ZnO utilization at breakthrough are achieved. H₂S concentrations from 60 to 2000 parts per million in volume (ppmv) can be reduced to as little as 0.6 ppmv at 400°C in 30% H₂O at a face velocity of 1.7 cm/s for layers as thin as 1.0 mm. At 500 to 600°C, ZnO/SiO₂-entrapped materials provide much higher regenerability in air than do 1 to 2 mm commercial extrudates. The use of glass fibers permits greater than 50 regeneration cycles. This paper was presented at the ASM Materials Solutions Conference & Show held October 18–21, 2004 in Columbus, OH.