Error Estimates for Semidiscrete Finite Element Approximations of the Stokes Equations Under Minimal Regularity Assumptions

Semidiscrete (spatially discrete) finite element approximations of the Stokes equations are studied in this paper. Properties of L ², H ¹ and H ^–1 projections onto discretely divergence-free spaces are discussed and error estimates are derived under minimal regularity assumptions on the solution.     

工程总承包公司的合同管理研究

山东鲁能工程有限责任公司开展电力工程总承包始于上世纪九十年代中期,近五年来总承包事业发展迅速,公司陆续签订了嘉峪关宏晟2×300M W电厂、重庆永川2×125M W电厂、费县2×600M W电厂脱硫、章丘2×300M W电厂脱硫、潍坊2×25M W电厂、单县1×25M W生物发电厂等一批总承包合同,均采用了国际上通行的FID IC合同条款。为规范公司的经营管理,防范合同风险,维护公司合法权益,我们研究摸索了一套适应矩阵管理的总承包公司合同管理体系,在此做简要介绍,与同行交流。一、合同管理中常见问题合同是市场经济下确定不同主体之间经济关系的重…     

Observation and computer simulation of multicomponent chemical short-range order （MCSRO） for the bulk metallic glasses

The atomic configuration of chemical short-range order (CSRO) for the Zr-base metallic glasses was investigated by using nano-diffraction and high resolution transmission electronic microscopy (HRTEM) technology with a beam size of 0.5 rim. It is illustrated that the pattern of atomic configuration of CSRO might have various compound counterparts because of the chemical interaction of bonding atoms. Some atomic configuration of MCSRO is similar to the icosahedral structure with 10-fold symmetry of very weak spots. In deed, the nano-beam technology could clearly detect the evolution of atomic configuration in nanometer scale during the transformation from the metallic melt to the primary crystallization. The local atomic configuration of CSRO is also investigated by molecular dynamics simulation (MD) for the Zr2Ni compound in a wider temperature range. The CSRO in the melt could be pictorially demonstrated as distorted coordination polyhedron of the compound structure and/or the structure similar to cubo-octahedron analogs. The MD simulation illustrates that the atomic packing of long-range order disappears just above the melting point, but the chemical interaction of bonding atoms still exists that leads to form the various CSRO with the atomic configuration similar to stable or metastable unit cell of Zr2Ni compound. The icosahedral polyhedron became more abundance as the overheating temperature was raised.     

汽车照明防眩的新技术

文章介绍了一种新颖的汽车照明防眩技术，这是汽车前照灯的脉冲化照明所带来全新功能之一。通过利用高速频闪的脉冲氙灯，配合高速液晶电光开关制成的挡光板，让对方照明效果光透过，而挡去大部进入眼睛的外部眩光，从而达到防止眩光的目的。本文详细论述了这种新颖的防眩控制技术，并给出了在实用中多车交会时的处理方法。     

Advances in selective wet oxidation of AlGaAs alloys

We review the chemistry, microstructure, and processing of buried oxides converted from AlGaAs layers using wet oxidation. Hydrogen is shown to have a central role in the oxidation reaction as the oxidizing agent and to reduce the intermediate predict As₂O₃ to As. The stable oxide is amorphous (Al_xGa_1-x) ₂O₃ which has no defects along the oxide/semiconductor interfaces but can exhibit strain at the oxide terminus due to volume shrinkage. The influence of gas flow, gas composition, temperature, Al-content, and layer thickness on the oxidation rate are characterized to establish a reproducible process. Linear oxidation rates with Arrhenius activation energies which strongly depend upon AlAs mole fraction are found. The latter produces strong oxidation selectivity between AlGaAs layers with slightly differing Al-content. Oxidation selectivity to thickness is also shown for layer thickness <60 nm. Differences between the properties of buried oxides converted from AlGaAs and AlAs layers and the impact on selectively oxidized vertical cavity laser lifetime are reported     

Microstructures of laser cladding of intermetallic-ceramic composite coatings

The microstructures of laser cladding of (Ni-24.5%(atom fraction)Al)+5O%(mass haction)WC coatingsbefore and after aging was comparetively studied by using SEM and TEM. It is shown that dissolving of WC and reprecipitating in the forms of WC and W,Coccurred during laser cladding, and intermetallic γ' (Ni3Al) orderly precipitatefrom metastable supersaturant Ni-matrix solid solution after heat treatment. The structures are favorable for coating'sproperties.     

一点对多点通讯在卫星测试无线转发系统中的应用

分析了卫星测试无线转发中一点对多点通讯系统中的关键性技术：包括硬件连接、通讯方式及有关技术，并给出了具体方案。     

矩形花键螺旋沟拉刀一次成型中的数学模拟

给出了矩形花键螺旋沟拉刀一次成型的数学模拟，并用实例验证了模拟的可靠性。     

An improved outer pipe method for expansive pressure measurement of static cracking agentsOA

Static cracking agent(SCA) is actively investigated as an alternative to explosive blasting for rock breakage due to its immense expansion property. SCA can eliminate the negative effects of shock, noise and harmful gases encountered in explosive blasting processes. Accurate measurement and deep understanding of the expansive properties of SCAs are important in their industrial application. An improved outer pipe method(OPM), termed the upper end surface method(UESM), is proposed in this paper t...     

AP-6-6型汽轮机主轴推力盘改造及运行实践

从介绍苏制 ６ Ｍ Ｗ 汽轮机主轴推力盘结构和运行中出现的问题着手,提出了改造推力盘的措施和方法。运行实践表明,机组运行的稳定性和带负荷响应能力有了明显的改善