Investigation of fusion reactions in palladium and titanium tritide using galvanostatic,coulometric, and hydrogen permeation techniques

We describe several electrochemical methods used to investigate the possibility of cold fusion phenomena in palladium and titanium tritide cathodes. We performed long-term (up to 77 days) electrolysis experiments with electrochemical cells of the University of Utah type at current densities as high as 1 A/cm², while monitoring neutron and tritium levels. With some cells, we pulsed the current to determine if neutron bursts would result. In another cell, we used titanium tritide as the cathode to determine if D-T reactions yielding neutrons would occur. In no instance were levels of neutrons or tritium significantly above background except in the titanium tritide cell where isotopic exchange, occcurring between the electrode and the electrolyte, resulted in significant tritium levels. We also combined x-ray photoelectron spectroscopy (XPS) and electrochemical hydrogen permeation experiments to determine the effectiveness of various Pd surface treatment procedures on the resultant electrochemical hydrogen absorption efficiency. Electroanalytical and thermal desorption/gas analysis techniques indicated the maximum loading of H in Pd was to a ratio of HPd=0.8.     

An implicit enthalpy scheme for one-phase Stefan problems

A compact finite-difference scheme to solve one-phase Stefan problems in one dimension is described. Numerical experiments indicate that the moving interface is obtained withO(t) accuracy when 3–4 iterations per time step are used to solve the nonlinear implicit scheme. The scheme can be adapted to ADI methods in higher dimensions.     

云计算安全需求分析研究

云计算是当下发展迅速的信息技术之一。由于其外包式的服务方式,云计算中的安全问题受到人们格外关注。只有妥善地保障云计算的安全,才不会掣肘云计算的发展和推广。鉴于云计算的复杂性和多面性,文章着眼云计算有别于传统技术的新特点、新趋势,首先提出了考量云计算安全需求的多维视角,随后围绕云计算具体实施过程中的若干关键技术,对云计算中的安全需求进行了细致全面的分析和阐释。     

Measurement of the heat of fusion of titanium and a titanium alloy (90Ti-6Al-4V) by a microsecond-resolution transient technique

A microsecond-resolution pulse heating technique was used for the measurement of the heat of fusion of titanium and a titanium alloy (90Ti-6Al-4V). The method is based on rapid (50- to 100-s) resistive self-heating of the specimen by a high-current pulse from a capacitor discharge system and measuring, as functions of time, current through the specimen, voltage across the specimen, and radiance of the specimen. Melting of the specimen is manifested by a plateau in the measured radiance. The time integral of the net power absorbed by the specimen during melting yields the heat of fusion. The values obtained for heat of fusion were 272 J · g^–1 (13.0 kJ · mol^–1) for titanium and 286 J · g^–1 for the alloy 90Ti-6Al-4V, with an estimated maximum uncertainty of ±6% in each value.Paper presented at the Second Workshop on Subsecond Thermophysics, September 20–21, 1990, Torino, Italy.     

Web服务器安全威胁与防范技巧

WEB服务器主要是面向互联网的,随着人们对互联网服务的需求不断扩大,各种互联网应用服务日益增多,Web服务器便成为众多信息化应用中最容易遭受攻击的对象。文章中主要介绍了几种常见的Web服务器安全威胁,并提出了相应的安全防范技巧。     

类金刚石膜的制备及其影响因素

概述了近年来制类金刚石膜的新技术如双射频辉光放电（RF－RF）法，射频－直流辉光放电（RF－DC）法和微波－射频（MW－RF）法等，并且对影响类金刚石膜制备及性能的因素如基体材料，制备类金刚石膜时在膜中添加元素，类金刚石膜与基材之间的中间层等进行了较全面的分析。     

Preparation of alumina-doped yttria-stabilized zirconia nanopowders by microwave-assisted peroxyl-complex coprecipitation

Alumina-doped yttria-stabilized zirconia （ADYSZ） nanopowders were prepared by microwave-assisted peroxyl-complex coprecipitation （MAPCC） using ZrOCl2-8H2O, Y2O3 and AICly6H2O as starting materials, NH2-H2O as precipitant and H2O2 as complexant. The effects of adding H2O2 and microwave drying on the preparation and properties of ADYSZ were investigated. The precursors and nanopowders were studied by EDX, XRD, SEM and TEM techniques. The results show that the uniformity of component distribution within ADYSZ nanopowders is improved by adding appropriate dosage of H2O2. Complexing reaction between H2O2 and Zr^4＋ ion restrains the hydrolyzation and precipitation of Zr^4＋ ion. With the addition of H2O2, Al^3＋, y^3＋ and Zr^4＋ ions can be precipitated synchronously in a relatively narrow range of pH value. H2O2 also improves the filterability of the wet precipitate. The highly hydrophilic precipitates can be quickly and effectively separated from aqueous solution. During microwave drying process, the moisture of wet precursors is selectively heated. Quick expansion of steam vapor within the wet colloidal particles causes the aggregations burst into numerous tiny lumps. Compared with oven drying, microwave drying can not only shorten drying time but also reduce aggregation intensity of the resultant ADYSZ nanopowders.     

喷雾干燥法制备的Yb2O3(Al2O3)-8YSZ超细粉的性能

研究了用喷雾干燥法处理Yb2O3掺杂的氧化锆超细粉的性能。采用LS800型激光衍射粒度分析仪、JB-1型氮吸附比表面仪、Rigaku-DmaxⅡ型X射线衍射仪（XRD）和JSM-6700F型扫描电镜（SEM）分析了喷雾干燥法制备的Ybn（Al2O3）-8YSZ超细粉的粒度分布和比表面积，研究了粉末微观形貌特征。结果表明，制备的是球形颗粒、分散性好．晶粒尺寸均匀的超微细2％Yb2O3（Al2O3）-8YSZ（摩尔分数）粉末。     

快干涂料铸渗法获得铸件表面复合层的研究

对快干涂料法铸渗工艺进行了研究。查明了影响铸件表面复合层质量的主要工艺因素,确定了最佳工艺参数,为生产实践提供了依据。     

钢结硬质合金材料的研究进展

介绍了钢结硬质合金的性能特点及制备工艺,简述了近年来在钢结硬质合金领域开展的研究与取得的进展,对钢结硬质合金的应用进行了分类归纳,展望了其发展前景。