难熔金属及硅化物薄膜制备技术研究

本文对难熔金属及其硅化物的形成、特性进行了研究．主要对难熔金属Mo、难熔金属硅化物TiSi2、PtSi2等进行了探讨．采用溅射难熔金属、热硅化反应的手段，对解决VLSI工艺的某些问题，如：解决由于MOS电路图形尺寸缩小带来的概电阻增大的问题以及采用硅化物（如PtSi2）一阻挡层（W、MO、Ti等）一Al多层金属布线、解决欧姆接触和铝的电迁移问题起了极好的作用．     

不同沉淀剂对铈锆复合稀土氧化物性能的影响

通过选用不同的沉淀剂,利用共沉淀法制备出掺杂过渡金属元素（Fe,Mn,Cu）的CeO_2^-ZrO₂多元稀土复合氧化物。样品用X射线衍射（XRD）,液氮吸附法（BET）测定比表面积和H2程序升温还原(H_2^-TPR)等进行了表征。研究结果表明：以碳酸铵作为反应的沉淀剂制得的样品,可以较好的形成固溶体,并且该固溶体具有大的比表面积,良好的低温还原性能以及高的储氧能力。样品经过1000℃,4h处理后,会发生烧结,其高温热稳定性需要进一步的加强。     

金属硅化物在电阻薄膜材料中的应用

研究了金属硅化物在电阻薄膜材料中的应用．用真空感应熔炼精密浇铸方法制备含铬和镍的硅化物，作为溅射沉积电阻薄膜的溅射阴极靶材．发现随着硅含量的增加，溅射得到的薄膜电阻值变大，Ｓｉ含量在５０％（质量分数）以上时，溅射阴极靶材的组成由ＣｒＳｉ２，ＮｉＳｉ两相变成Ｓｉ，ＣｒＳｉ２和ＮｉＳｉ２三相．所研制的三种型号的溅射阴极靶材适用于不同电阻值范围的电阻薄膜的溅射沉积，可在金属膜和金属氧化膜电阻器上应用．     

Single-crystal metallic nanowires and metal/semiconductor nanowire heterostructures

Substantial effort has been placed on developing semiconducting carbon nanotubes and nanowires as building blocks for electronic devices--such as field-effect transistors--that could replace conventional silicon transistors in hybrid electronics or lead to stand-alone nanosystems. Attaching electric contacts to individual devices is a first step towards integration, and this step has been addressed using lithographically defined metal electrodes. Yet, these metal contacts define a size scale that is much larger than the nanometre-scale building blocks, thus limiting many potential advantages. Here we report an integrated contact and interconnection solution that overcomes this size constraint through selective transformation of silicon nanowires into metallic nickel silicide (NiSi) nanowires. Electrical measurements show that the single crystal nickel silicide nanowires have ideal resistivities of about 10 microOmega cm and remarkably high failure-current densities, >10(8) A cm(-2). In addition, we demonstrate the fabrication of nickel silicide/silicon (NiSi/Si) nanowire heterostructures with atomically sharp metal-semiconductor interfaces. We produce field-effect transistors based on those heterostructures in which the source-drain contacts are defined by the metallic NiSi nanowire regions. Our approach is fully compatible with conventional planar silicon electronics and extendable to the 10-nm scale using a crossed-nanowire architecture.     

硅微透镜阵列与红外焦平面阵列的单片集成

基于标量衍射理论 ,考虑焦距长度与微透镜尺寸的关系 ,提出了一种新的制作二元光学衍射微透镜的方法———部分刻蚀法 .利用这种方法制作了 2 5 6× 2 5 6硅微透镜阵列 ,并将其与PtSi红外焦平面阵列单片集成在一起 ,使红外焦平面阵列的灵敏度R和比探测率D 都提高了 1.7倍     

Microstructure and growth kinetics of Ce and Y jointly modified silicide coatings for Nb–Ti–Si based ultrahigh temperature alloy

In order to protect Nb-Ti-Si based ultrahigh temperature alloy from oxidation, pack cementation processes were utilized to prepare Ce and Y jointly modified silicide coatings. The Ce and Y jointly modified silicide coating has a double-layer structure: a relatively thick (Nb, X)Si2 (X represents Ti, Cr and Hf elements) outer layer and a thin (Ti, Nb)5Si4 transitional layer. The pack cementation experiments at 1150 ℃ for 8 h proved that the addition of certain amounts of CeO2 and Y2O3 powders in the packs distinctly influenced the coating thickness, the contents of Si, Ce and Y in the (Nb, X)Si2 outer layers, and the density of cavities in the coatings. In order to study the effects of Ce and Y joint modification in the silicide coatings, both only Ce and only Y modified silicide coatings were also prepared for comparison. The mechanisms of the beneficial effects of Ce and Y are discussed. A pack mixture containing 1.5CeO2-0.75Y2O3 (wt%) powders was employed to investigate the growth kinetics of the Ce and Y jointly modified silicide coating at 1050, 1150 and 1250 ℃. It has been found that the growth kinetics obeyed parabolic laws and the parabolic rate constants were 109.20 mm2/h at 1050 ℃, 366.75 mm2/h at 1150 ℃ and 569.78 mm2/h at 1250 ℃, and the activation energy for the growth of the Ce and Y jointly modified silicide coating was 197.53 kJ/mol.     

ASP网站设计的安全探讨

从系统与应用程序设计两个层面探讨ASP网站设计中的安全问题。一方面，在系统层上通过下载最新补丁程序和采用MTFS格式等措施来提高ASP网站安全性；另一方面，在应用程序设计中通过身份认证与加密来解决ASP网站安全问题。     

Influence of reaction stresses induced by dislocation slips on the orientation evolution in bcc metals

A plastic deformation model for bcc metals is proposed in consideration of reaction stresses.The shear strains and the corresponding reaction stresses induced by the activation of dislocations are calculated in the model,which will influence the following dislocation activation.The rolling texture in bcc metals is simulated up tp 80% reduction,whille the ratio of critcal resolved shear stresses between the dislocations slippingon the {110}and{112}planes is chosen as 0.95.The corresponding calculation is also conducted with the activation of second dislocation,if the difference between the orientation factor of the two dislocations with maximal orientation factors is lower than 5%.It is shown that the simulated texture is closer to that of the 80% rolled interstitial free steels than other modeling.It is believed that the new model can give more attention to both of the strain and stress continuities during the plastic deformation of polycrystalline metals,and therefore approaches closer to the real deformation process in bcc metals.     

一种全文索引自动答疑系统的设计与实现

提出一种基于自然语言提问的自动答疑系统的设计思想,引入Lucene的全文检索模型.采用浏览器/服务器模式,设计并实现基于Lucene的自动答疑系统,通过对提问信息进一步的加工和提取,可实现浏览、搜索、提问等功能.该系统能够胜任一定领域内的,基于自然语言的自动答疑需求,并充分考虑了系统的开放性和可维护性的要求.然而,知识库还不具备自动学习功能,且对用户问题只进行简单的关键词拆分,没有进行语义分析,这使得系统还不具有完全的智能化特性.     

城市垃圾焚烧飞灰理化性质及处理技术

焚烧法处理城市垃圾已在世界先进发达国家广泛采用,而城市垃圾焚烧处理引起的二次污染问题已引起人们的高度关注,特别是垃圾焚烧飞灰的安全有效处置成为急需解决的环境和社会问题．通过分析垃圾焚烧飞灰的物理化学性质,对目前国内外城市垃圾焚烧飞灰处理技术进行了系统分析和讨论,归纳出目前国内垃圾焚烧飞灰处理的主要方式为安全填埋、固化稳定化和重金属提取,提出适合于中国垃圾焚烧飞灰无害化处理的途径和方式：开发先进的焚烧炉,加强对入炉垃圾的控制：研究稳定效果好、处理成本低的化学稳定剂以及有效的重金属分离提取方法,以减少垃圾焚烧飞灰中重金属造成的二次污染．