FeOT-CaO-SiO2-Al2O3渣系中铅及其氯化物蒸汽压测定

利用Knudsen喷射法测试FeOT?CaO?SiO2?Al2O3渣系中铅及其氯化物的蒸汽压。结果显示该复杂体系中铅及其氯化物的蒸汽压随温度升高而升高。对于不含氯元素的渣系,铅的挥发气体种类为PbO 和金属Pb。二者蒸汽压的对数(lnp)与温度的倒数(1/T)之间呈良好的线性关系。金属 Pb 蒸汽形成比例越高,总的蒸汽压越高。铅的蒸汽压随FeOT?CaO?SiO2?Al2O3渣系碱度的升高、随FeO含量及w(Fe2+)/w(Fe3+)比例的升高而升高。对于含有Cl元素的渣系,铅的挥发气体种类为PbCl2和PbCl,二者总的蒸汽压随渣碱度及FeO含量的降低而升高。     

Switched-capacitor discrete Fourier analyser with window function circuit

An analogue window function circuit is realized by using switched-capacitor techniques. In order to verify the effect of this window, a novel switched-capacitor analogue discrete Fourier analyser is proposed. The window function circuit is included in this analyser as the ratios of capacitances. This switched-capacitor discrete Fourier analyser is very simple in construction, namely, only two elemental circuits based on the integral feedback capacitance circuit are connected in series. Agreement between the experimental and the theoretical values is confirmed.     

Scaling of cylindrical shells under axial impact

A technique of correcting scaled strain rate sensitive structures subject to dynamic loads is described and applied to a shell under axial impact. The prototype and models responses were simulated using finite element method. Final deformed shape, collapse mode, displacement at the top of the shell and maximum force of scaled models are compared to the respective prototype. It is shown that the models response are quite different from the prototype if no correction is performed. By correcting the initial impact velocity, the models scale quite well and it is even possible to obtain the transition phenomenon between global and progressive buckling of shells subject to the axial impact of a mass.     

Influence of sub-micrometer notches on the fracture of single crystal silicon thin films

The influence of notches on the fracture of single crystal silicon thin films was investigated. The tests were conducted on notched and smooth tensile specimens micromachined on a silicon wafer. The specimen geometry was 100 μm long, 50 μm wide and 5 μm thick. For the notched specimen, a V‐shaped sub‐micrometer notch was introduced on one edge of it by using a focused ion beam (FIB) process. The notch lengths ranged from 0.07 to 1.3 μm. Four types of specimens with different surfaces and tensile orientations were tested. The smooth specimens showed scattered fracture strengths and ‘collapsed’ fractures. For the restrictive‐shaped notches, the critical length was 0.5 μm. The short‐notched (<0.5 μm) specimens also showed ‘collapsed’ fractures, and the stress concentrations on notch tips decreased their fracture strengths. For the long‐notched (>0.5 μm) specimens, the notch was equivalent to a crack in the Griffith model and the crack mainly propagated on {111} cleaved planes.     

A Microcomputer System for Spatiotemporal Visual Receptive Field Analysis

A microcomputer system was developed to measure visual spatiotemporal receptive fields. The system performs three functions: 1) generation of a binary spatiotemporal white-noise stimulus, 2) acquisition of spike discharges from retinal ganglion cells, and 3) extraction of the linear part of the spatiotemporal receptive flelds by cross correlating the input against the output. We have applied this system to the measurement of the spatiotemporal receptive fields of cat and catfish retinal ganglion cells.     

Nanostructured coatings produced by a novel ultrasonic-assisted method: Coating characterisation and formation mechanism

In this study, we introduce a novel method of mechanical plating to produce nanopowder coatings on a number of metal substrates by using TiN nanopowder as a representative example. This method, proposed earlier by the authors, allows a coating to be applied at room temperatures and atmospheric pressure in a relatively short time. These coatings were characterised for microhardness, roughness, and scratch adhesion. Their micro- and nanostructures were investigated by SEM and TEM. On the basis of the results of these analyses, possible mechanisms of coating formation were tentatively proposed and discussed. To further elucidate the coating formation mechanisms and to estimate the process capability, a mathematical model was developed and verified against the experimental results.     

黏滞阻尼器的优化布置及其在高层钢结构加固中的应用

阻尼器优化布置是结构减震设计过程中的重要环节,通常需要通过多次动力响应计算来完成。为此,提出了一种通过结构静力分析确定阻尼器合理布置位置的方法,并能够快速计算出优化方案的附加阻尼比。将该方法应用于一栋位于日本东京都新宿区29层钢结构建筑的减震加固设计中,分析了该建筑的强震观测系统在日本“311地震”中采集到的部分楼层加速度时程数据,并基于分析结果验证了所建立的非线性数值分析模型的可靠性。采用所提方法对结构进行减震加固,得到双向共64个阻尼器的优化布置方案及其附加阻尼比,并通过动力方法对结果进行了验证。同时针对长周期及长持时特性的地震波,对减震结构进行动力弹塑性时程分析,评估其抗震性能。分析结果表明：减震优化方案的减震效果明显,结构整体地震反应和构件损伤较非减震方案都大大减小;减震优化方案有效改善了高层钢结构楼层变形不均匀的情况,层间位移角均满足小于1/100的性能要求;通过减震优化后大部分钢支撑和钢梁的塑性率都降低至小于1。     

Transcutaneous Blood Flow Measurement by Electromagnetic Induction

A new induction flowmeter which can measure the blood flow from the skin surface is discussed theoretically and experimentally. A pair of electrodes placed on the skin detect the EMF induced by the interaction of the blood flow and a magnetic field applied from outside the skin. The relation between the EMF and the flow rate, which is obtained theoretically, is also confirmed experimentally within the error of 10 percent.