Analysis of the detectivity for triple-layer heterojunction GaSb/GaInAsSb infrared detectors

In this paper, the detectivity is calculated and analyzed with the front-or backside illuminated case for both N-GaSb/p₂-Ga_0.8In_0.2As_0.19Sb_0.81/p₁-Ga_0.9In_0.1As_0.09Sb_0.91 and N₁-GaSb/n₂-Ga_0.9In_0.1As_0.09Sb_0.91/p-Ga_0.8In_0.2As_0.19Sb_0.81 infrared photovoltaic detectors, respectively. The analysis results show that the main absorption appears in the p-type Ga_0.8In_0.2As_0.19Sb_0.81 material with either front- or backside illuminated case for above two structures. In each structure, the carrier concentration obviously affects the detectivity. The carrier concentration in the wide-bandgap material for the isotype heterojunction should be reduced as low as possible to reduce the tunneling rate at the isotype heterointerface. Moreover, the change of the detectivity with the p-side surface recombination velocity for the N₁-n₂-p structure is more sensitive than that with the p₁-side surface recombination velocity for the N-p₂-p₁ structure. In the N-p₂-p₁ structure with the incident light from the p₁-side surface, two-color detection is achieved.     

微波热液法制备光催化TiO2功能材料

采用微波加热法，研究了钛配离子热分解水解反应的规律。结果表明，水解产物在大气气氛和300℃下煅烧2h，所得产物为锐钛型TiO2粉末。在紫外线照射下，乙酸经Ti02光催化反应12h后，残余量小于初始量的20％。     

Cohesive stresses and size effect in quasi-brittle materials

A novel approach to the derivation of Bažant’s size effect law is presented. Contrarily to the original Lagrangian derivation which hinged on energetic consideration, a Newtonian approach based on local stress intensity factors is presented. Through this approach, it is shown that Bažant’s size effect law is the first (and dominant) term in a series expansion for the nominal stress. Furthermore, analytical expressions forB are derived for selected specimen geometries.     

如何正确选择合适的耐蚀材料

文章较全面的介绍了如何根据设备、装置、构件所处的工作环境及使用条件进行防腐蚀设计,及其防腐蚀设计的内容和注意事项,选择合适的防腐蚀材料,确保产品的使用寿命     

弹性筛管防砂技术

弹性筛管防砂技术是根据稠油油藏高轮次吞吐和蒸汽驱井防砂生产需要而研制的筛管防砂新技术。进行了筛管结构优化、加厚过滤单元外罩设计、固定方式研究、弹性过滤材料筛选、防腐实验研究等。室内试验表明，筛管的过流能力在900cm^2／m以上、渗透率在100μm^2以上、筛管抗内、外压强度达到20MPa、防砂粒径在0.1mm以上、耐温350℃、pH值在3～12之间不被腐蚀。现场试验证明，该技术防砂和抗堵塞性能好，防砂有效期长，地层适应性强，施工简便，防砂生产效果明显，具有良好的应用前景。     

焦化生产中含硫容器自燃氧化倾向性分析

分析了炼焦化工生产过程中硫的分布和存在形态、硫铁化合物自燃的影响因素,提出了防止储罐、管道等设备自燃事故的安全控制方法.     

Development of sealing compositions with nanostructure iron-based fillers

The possibility of utilizing nanopowders of iron and Fe-Co-Ni produced bu a thermochemical method in the fabrication of sealing composition materials is investigated. It is established that such hermetic sealing composition materials function reliably under extremal conditions and guarantee elevated strength of adhesion to the surface of the metal and high corrosion and temperature stability. __________ Translated from Poroshkaya Metallurgiya, Nos. 3–4(448), pp. 112–117, March–April, 2006.     

纳米镍粉的制备工艺及产业化研究进展

综述了纳米镍粉的制备方法(包括物理法和化学法)及产业化现状,对纳米镍粉的各种制备方法进行了分析和评价。与物理法相比,化学法的产量高、成本低廉,能制备出性能优异的纳米镍粉,适合规模化生产;使用化学法制备的纳米镍粉的纯度、粒径及成本的控制仍需进一步加强。同时,对今后纳米镍粉的制备和产业化发展提出了建议。     

电解多功能天车打壳机构非正常失效的分析及解决方案

主要分析了电解多功能天车打壳机构中打击头、夹套、拉杆非正常失效的原因,并提出了解决的方案.