浅谈建筑物变形缝的设置与施工措施

针对建筑物变形缝的设置．主要从“抗”和“防”以及“抗’’和“调’’两个方面,给出伸缩缝和沉降缝的施工措施。     

Thermal Properties of Maleated Polyethylene/Layered Silicate Nanocomposites

Nanocomposites are a new class of composites in which the reinforcing phase dimensions are on the order of nanometer scale. In particular, the layered silicates are considered to be good candidates for the preparation of polymer-inorganic nanocomposites. The mechanical and thermal properties of polymer can be altered by adding a few vol% of the nano-particles. The effect of the nano-sized particles on thermophysical properties such as melting and crystallization, coefficient of thermal expansion, and thermal conductivity was studied. After preparing the PEMA/layered silicate nanocomposites, the thermophysical properties were investigated by the differential scanning calorimetry and 3 methods. The content of layered silicate was varied from 0.5 to 5 vol%.     

Density and Thermal Expansion of Liquid Au-Cu Alloys

The density of liquid Cu-Au alloys is measured using the technique of electromagnetic levitation, which entails producing a shadow image of the sample. The shadow is recorded by a digital CCD-camera, and the volume of the sample is calculated by an image processing algorithm. The density and thermal expansion of several alloys and the pure elements copper and gold are investigated at various temperatures above their melting points. In addition, the densities are also investigated as a function of the gold concentration at constant temperature. The measured values agree with literature data and with predictions obtained by molecular dynamics. It was found from data analysis that the ideal solution model applies.     

Thermophysical Properties of Fluids: From Realistic to Simple Models and Their Applications

Recent systematic and extensive computer simulations on realistic models of polar and associating fluids have shown that the long-range interactions have only marginal effect on the properties of these fluids. This finding leads to short-range models upon which a perturbation theory may be developed. An attempt to develop a methodology to construct such models (called primitive models) directly from the parent realistic models without resorting to (or reducing at least to minimum) ad hoc adjustments is presented and exemplified by constructing models of methanol, water, and carbon dioxide. It is shown that the structural properties of the primitive model fluids obtained by means of purely theoretical considerations compare well with those of their realistic counterparts.     

Global controllability of linear autonomous systems: A geometric consideration

The global controllability in finite time of a linear autonomous system with restrained controls is investigated. Necessary and sufficient conditions are obtained by an approach based on the consideration of geometric properties of the system.     

Microstructural Design and Properties of LaCoO3/La2(Zr,Y)2O7−δ Composites

LaCoO_3–/La₂(Zr,Y)₂O₇-based composites were designed in view of three main properties: electrical conductivity, thermal expansion and resistance to thermal cycling. Composition and processing conditions were investigated on the basis of an experimental plan according to the Taguchi method. The phase distribution was estimated from image analysis and related to electrical and thermo-mechanical behavior. Results indicate that an homogeneous and fine grained phase distribution is essential in order to obtain materials with the desired thermal expansion, electrical properties and thermomechanical properties.     

散乱点云的三角划分算法研究

通过对当前的三角网格划分方法进行比较分析,提出了一种散乱点云的3D三角网格划分算法。该算法不需如同二维划分方法那样要对散乱点云对应的自由曲面分片投影,而是直接在3D空间,根据离散点集所对应的曲面形态变化,利用网格扩展、边界环分裂和边界环封闭,逐层收缩生成三角网格。该算法能方便地处理空间多种曲面的散乱点云数据,并且生成的三角网格形态优良,布局合理。     

Linux内核系统调用扩展研究

系统调用是操作系统内核提供给用户使用内核服务的接口。Linux操作系统由于其自由开放性,用户可在原有基础上,添加新的系统调用,以便提供更多的服务。基于Linux2.4内核,文中研究了Linux操作系统系统调用的实现机制,并以基于数据库的文件系统功能扩展为例,说明系统调用扩展的实现过程。     

地下室防渗控制

地下室工程采用UEA混凝土技术，用膨胀加强带替代后浇缝，通过调整UEA掺量改善混凝土收缩变形，控制裂缝出现，降低混凝土浇筑温度，合理配筋，加强养护，确保地下室无渗漏。