Calculation of the Heat Flux on the First Wall During Disruption on Tokamak

Disruptions are the most dangerous instabilities in tokamak plasma. During plasma disruption, the large amounts of energy will be deposited on Plasma Facing Components (PFCs) which is a damaging threat for the divertor target and the first wall materials. Therefore, studying the characteristic of heat deposition on the first wall is very significant. The Infrared (IR) camera is an effective tool to measure the surface temperature profile on the first wall on the Experimental Advanced Superconducting Tokamak (EAST). With a finite difference method, the heat flux arrived to the divertor can be calculated from the surface temperature. However, the surface layer on the divertor has a great influence on the calculation of the heat flux on the divertor. The numerical method for solving heat conduction for semi-infinite model is given in this paper. And the thermal resistance of surface layers is considered in this numerical method. In addition, the distribution of heat flux on the divertor during disruption is also shown.     

基于材性的混凝土结构及构件冻融损伤模型试验研究

基于蔡昊模型,通过理论推导并结合既有冻融材性试验数据,对模型中最大静水压力计算方法进行改进。进行9组材性试验,建立了混凝土水灰比和最大结冰速率之间的拟合关系,推导出最大静水压力的简化解析计算公式。采用ANSYS有限元软件,对构件截面温度场分布进行了模拟,得到考虑温度场修正的冻融损伤模型。最后,设计2组试件,对改进冻融损伤模型的准确性与可靠性进行试验验证,结果表明：修正后的采用动弹模损伤作为物理损伤指标的冻融损伤模型,可为RC构件与结构层面冻融损伤机理研究提供理论支撑。     

基于OLED 的图形发生器信号主机 硬件设计与研究

本文描述了OLED图形发生器信号主机的硬件实施方案,该方案通过对硬件系统架构、硬件模块间的协作、模 块的输入和输出端口的描述来明确设计方向,同时为每个硬件模块的进一步设计、硬件集成测试、售后维护等工作提供依据。     

网络数据库安全机制研究

随着计算机技术及互联网技术的快速发展,人们逐渐进入现代化信息时代。利用各种现代化信息手段,人们 的工作及生活都变得更加便利。但同时,也有不法分子利用网络的便利性不断进行网络安全攻击,使网络数据库安全受到威 胁,信息的传输及处理受到影响,为此就需制定一套完善的网络数据库安全机制以保证网络数据库的安全性。文章简单概述 了网络数据库安全机制的基本概念、网络数据库的模式及其安全机制模型,分析了网络数据库各层的安全机制,并讨论了利用 DBMS 安全机制来防范网络攻击问题,旨在为提高网络数据库的安全性提供若干建议。     

基于CVT二次信号的行波故障定位系统

介绍基于电压信号的行波定位原理,并阐述基于这种原理的行波故障定位系统构成,硬件和软件系统的设计原则及关键环节。行波故障定位系统采用自动定位与手动定位相结合的方法,实现了定位的灵活性与协调性,满足运行现场的不同需求。     

邻氯苯基荧光酮光度法测定聚烯烃树脂中的钛

研究了以邻氯苯基荧光酮-十六烷基三甲基溴化铵为显色体系,在表面活性剂十六烷基三甲基溴化铵存在下,钛（Ⅳ）和邻氯苯基荧光酮所形成橙红色的络合物,实验结果表明,在酸性介质中钛（Ⅳ）最大吸收波长位于560nm,含量在0～12μg/25mL范围内符合比尔定律,其表观摩尔吸光系数ε560=1.2×10~5L·mol^-1·cm~（-1）。聚烯烃树脂的人工合成样中钛（Ⅳ）的平均回收率为101.9%,相对标准偏差为0.36%。采用抗坏血酸掩蔽剂消除了被测样中干扰离子的影响,实验结果表明聚乙烯和聚丙烯中钛（Ⅳ）的含量分别为0.1760μg·g^-1、0.6855μg·g^-1,其加标平均回收率分别为101.7%、99.8%。相对标准偏差分别为1.48%、2.43%。本方法选择性好,灵敏度高,简便易行。     

一种高精度主轴的磨削方法

通过改进中心孔结构,减少定位误差,在普通外圆磨床上磨削高精度主轴,圆度可稳定地达到1μm,甚至可达0．5μm。     

Silicon,flake graphite and phenolic resin-pyrolyzed carbon based Si/C composites as anode material for lithium-ion batteries

Si/C composites, based on nano-Si, flake graphite and phenolic resin-pyrolyzed amorphous carbon, were synthesized by liquid solidification and subsequent pyrolysis. The performances of the prepared Si/C composites are investigated by means of thermogravimetric analysis (TG–DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and galvanostatic cell cycling, as well as cyclic voltammograms. The results indicate that the initial charge capacity of the composites is 640.51 mA h g^?1 at a current density of 100 mA g^?1 and the initial coulombic efficiency is 73.82%. The Si/C composites also exhibit excellent cycling performances when cycled at different discharge/charge rates.     

The nature of Schwertmannite and Jarosite mediated by two strains of Acidithiobacillus ferrooxidans with different ferrous oxidation ability

Jarosite and Schwertmannite are iron-oxyhydroxysulfate materials. These materials gain increasing interest in geological and metallurgical fields. Especially, for it can effectively scavenge heavy metals, less toxic ions and better biocompatibility, the application potential in environment becomes more and more intriguing. In this study, the nature of Jarosite and Schwertmannite mediates synthesized by two strains of Acidithiobacillus ferrooxidans with different ferrous oxidation ability is investigated. The precipitates are characterized by SEM, XRD, FTIR, and TG/DSC analysis. The materials are varied in color, shape, surface area, elemental composition and crystallinity. The crystallinity of precipitate produced by A. ferrooxidans 23270 with lower oxidation ability in optimized medium is significantly better than the precipitate produced by A. ferrooxidans Gf. A. ferrooxidans Gf will tend to mediate the formation of Schwertmannite with the decreasing of monovalent cation concentration in optimized medium. Cr(VI) adsorption capacity difference exists among the four materials. The adsorption efficiency of Schwertmannite is higher than Jarosite. Adsorption capacity of the materials formed by A. ferrooxidans Gf is higher than that of A. ferrooxidans 23270. Adsorption capacity decreases with the increasing of crystallinity.     

Reliability assessment and mechanical characterization of Cu and Au ball bonds in BGA package

Extended reliability and mechanical characterisation of Au and Pd-coated Cu (Cu) ball bonds are useful technical information for Au and Cu wire deployment in semiconductor device packaging. This paper discusses the influence of wire type on the package reliability and mechanical performance after several component reliability stress tests. Failure analysis has been conducted to identify the associated failure mechanisms of Au and Cu ball bonds after reliability tests. Wire pull strength and ball bond shear (with its break modes) of both wire types are investigated after unbiased highly accelerated temperature and humidity stress test (UHAST), temperature cycling (TC) and high temperature storage life test (HTSL) at various aging temperatures. Reliability Weibull plots have been plotted for each reliability stresses. Obviously Au ball bond is found with longer time-to-failure in Unbiased HAST stress compare to Cu ball bonds. Cu wire exhibits equivalent package and or better reliability margin compare to Au ball bonds in TC and HTSL tests. Failure mechanisms of UHAST and HTSL have been proposed and its mean-time-to failure (t₅₀), characteristics life (t_63.2, η) and shape parameter (ß) have been discussed in this paper.