Synthesis of CdS nanoplates by PAA-assisted hydrothermal approach

Triangular and hexagonal CdS nanoplates, with average size about 100 nm and average thickness range from 10 to 30 nm, have been synthesized in the presence of poly (acrylic acid) (PAA) assisted hydrothermal process at 180 °C. The structural characteristics, morphology, and optical properties of the as-prepared CdS products were investigated. UV–vis spectroscopy measurement reveals that the products show a strong quantum size effect. Based on the experiment results, the possible formation mechanism of CdS nanoplates has been proposed.     

IT、AV类电子产品阻燃试验的选择

在实践的基础上,本文主要根据GB 8898-2001<音频、视频及类似电子设备安全要求>以及GB 4943-2001<信息技术设备的安全>中的要求,结合自身在工作中的一些经验总结,来简单的探讨一下IT、AV类电子产品的阻燃材料试验的选择.     

特殊地势深基坑多种围护设计与施工

上海新浦江城122-9号地块住宅基础施工中,针对地势特殊、基础埋深较深等实际情况,采用水泥搅拌桩、钻孔灌注桩、土钉墙、混凝土围檩与钢立柱、坑内加固等多种围护结构,保证了基坑顺利开挖。施工过程中围护结构周边未出现裂缝、下沉、倾斜等现象,且降低了施工费用。     

TRD-排桩工法在深基坑围护体系中的应用分析研究

周边环境复杂且需超深止水的深基坑围护结构大多采用地下连续墙围护体系,但由于其需重型机械设备施工且周期较长,对于施工现场场地条件局促、工期紧的工程项目,则无法适用。TRD-排桩工法围护体系可弥补地下连续墙围护体系局限性。本文依托工程实例对TRD-排桩工法围护体系的施工技术、变形控制效果和技术经济性进行研究。     

触发器型压力传感器的研究

本文报道了一种触发器型压力传感器，对这类传感器的电路结构和工作原理进行了理论分析。详细讨论了影响传感器特性的四种因素。定量地分析了调控三角波电压对传感器测量灵敏度和线性范围的影响。对实验结果进行了讨论，理论分析与实验结果基本一致。     

Free convection performance of circular cavities having two active curved vertical sides and two inactive curved horizontal sides

A detailed review of the archival reveals that the heat transfer and fluid flow characteristics of circular cavities have not been investigated so far and of course their physical features are not understood. A prominent application of these cavities arises in the miniaturized packaging of electronic components that are subject to strict constraints. This paper addresses primarily steady-state laminar natural convection of air in a circular cavity of diameter H inscribed in a square cavity of side H where the corresponding sides are in contact at four points. A third cavity, an arc–square cavity whose shape lies between the square and circular cavity shapes is included in the analysis. The finite volume method is used to perform the numerical simulations. The methodology takes into account the second-order-accurate QUICK scheme for the discretization of the convective term, whereas the pressure–velocity coupling is handled with the SIMPLE scheme. Since the air is not assumed a Boussinesq gas, it was decided to take all thermophysical properties as temperature-dependent. In the end, it has been demonstrated that the circular cavity possesses a superior balance between heat transfer enhancement and size in cross-section area in comparison with the standard square cavity. The side of the square cavity is similar to the diameter of the circular cavity.     

北美流行的散热器及供暖设计方案

介绍了美国，加拿大流行的供暖设计方案及其所用的散热器，对比了国内现行的散热器在高层建筑中常用的垂直串联管系统，并提出了供国内思考参考的意见。     

A SINGULAR INTEGRAL EQUATION SOLUTION FOR THE LINEAR ELASTIC CRACK OPENING DISPLACEMENT OF AN ARBITRARILY SHAPED PLANE CRACK: PART II REGULAR INTEGRAL SOLUTIONS

Abstract— The boundary value problem for an arbitrarily shaped plane crack embedded in a 3D linear elastic solid can be reduced to a governing hyper-singular integral equation. A discretizing procedure based on a triangulation of the crack area has been offered in Part I of this work. The main goal of Part I is to introduce the analytical results for the 18 resulting finite-part integrals defined over a triangular mesh area. The finite-part integrals occur in those triangles where the source point coincides with one of the element nodes. Mostly the source point lies outside of the considered triangle. In these cases the occurring area integrals are regular.
The aim of Part II is, therefore, the derivation of the closed form expressions for the relevant 18 regular area integrals. The resulting relations are of algebraic form which can easily be coded in compact form. Their numerical proof by two different methods shows the highest accuracy and, therefore, the correctness of the final solutions. The relevant numerical results are offered in Appendix I.
With the formulae provided in Part I and Part II of the paper the determination of the coefficient matrix, necessary for the calculation of COD values from a linear equation system, is precise and needs only minimum computer time.     

建筑工程深基坑围护结构渗漏封堵技术研究

文章结合上海世茂北外滩酒店工程实例,就工程围护结构中出现的渗漏原因进行分析,根据工程特点和现场的实际情况提出采取双排注浆加固措施,严格控制施工过程的质量。实践证明,采取双排注浆加固措施很好地解决了该工程出现的渗漏问题。     

封闭腔内MWCNT纳米流体自然对流传热的数值模拟

采用Fluent软件对封闭腔内纳米流体层流自然对流换热进行了数值模拟研究.重点分析了Ra数和纳米颗粒的体积分数对自然对流换热特性的影响.数值模拟结果表明:在机油中添加多壁碳纳米管(MWCNT)粒子并没有提高基液的自然对流传热特性;对于给定的Ra数下,随着纳米颗粒体积分数的增大,纳米流体的传热特性也随之减弱;对于给定的体积分数,随着Ra数的增大,纳米流体的传热特性显著增强,但纳米流体的传热性能比机油的要弱,且在同一体积分数下随着Ra数的增大,传热性能减弱的程度要减小.