Ultrafast measurement of transient electroosmotic flow in microfluidics

We present a non-intrusive molecular dye based method, i.e., laser-induced fluorescence photobleaching anemometer (LIFPA), to significantly increase temporal resolution (TR) for velocity measurement of fast transient electrokinetic flows. To our knowledge, the TR has been for the first time achieved to 5–10 μs, about 100 times better than that published from state-of-the-art micro particle image velocimetry (μPIV), which is currently the most widely used velocimetry in the microfluidics community. The new method provides us with new opportunities to study experimentally the fundamental phenomena of unsteady electrokinetics (EK) and to validate relevant theoretical models. One application of the new method is demonstrated by measuring the rise time of DC electroosmotic flows (EOFs) in a microcapillary of 10 μm in diameter.     

Surface tension calculation of the Ni3S2---FeS---Cu2S mattes

The surface tension of the Ni₃S₂-FeS-Cu₂S ternary mattes have been calculated from those of the Ni₃S₂-FeS·FeS-Cu₂S and Cu₂S-Ni₃S₂ pseudo-binary boundary systems by using geometric models (Kohler and Toop model) and a general solution model (Chou model). Taking account of the experimental accuracy of ±2.5%, the respective calculated results are in agreement with the experimental data. At the same time, surface tensions of molten Ni₃S₂-FeS-Cu₂S mattes and their pseudo-binary boundary systems are predicted based on Butler's original treatment with great attention to the model parameter β. The predicted results also agree with the experimental data. Therefore, the resulting iso-surface tension curves in molten Ni₃S₂-FeS-Cu₂S mattes at 1473K, especially calculated by using Kohler, Toop and Chou models, are generally acceptable.     

A MEMS Thermal Biosensor for Metabolic Monitoring Applications

This paper presents a microelectromechanical systems (MEMS) differential thermal biosensor integrated with microfluidics for metabolite measurements in either flow-injection or flow-through mode. The MEMS device consists of two identical freestanding polymer diaphragms, resistive heaters, and a thermopile between the diaphragms. Integrated with polymer-based microfluidic measurement chambers, the device allows sensitive measurement of small volumes of liquid samples. Enzymes specific to a metabolic analyte system are immobilized on microbeads packed in the chambers. When a sample solution containing the analyte is introduced to the device, the heat released from the enzymatic reactions of the analyte is detected by the thermopile. The device has been tested with glucose solutions at physiologically relevant concentrations. In flow-injection mode, the device demonstrates a sensitivity of approximately 2.1 muV/mM and a resolution of about 0.025 mM. In flow-through mode with a perfusion flow rate of 0.5 mL/h, the sensitivity and resolution of the device are determined to be approximately 0.24 muV/mM and 0.4 mM, respectively. These results illustrate that the device, when integrated with subcutaneous sampling methods, can potentially allow for continuous monitoring of glucose and other metabolites.     

Design and application of a new series of gallbladder endoscopes that facilitate gallstone removal without gallbladder excision

In recent years, some Chinese doctors have proposed a new concept, gallstone removal without gallbladder excision, along with transition of the medical model. As there is no specialized endoscope for gallstone removal without gallbladder excision, we designed and produced a new series of gallbladder endoscopes and accessories that have already been given a Chinese invention patent (No. ZL200810199041.2). The design of these gallbladder endoscopes was based on the anatomy and physiology of the gallbladder, characteristics of gallbladder disease, ergonomics, and industrial design. This series of gallbladder endoscopes underwent clinical trials in two hospitals appointed by the State Administration of Traditional Chinese Medicine. The clinical trials showed that surgeries of gallstones, gallbladder polyps, and cystic duct calculus could be smoothly performed with these products. In summary, this series of gallbladder endoscopes is safe, reliable, and effective for gallstone removal without gallbladder excision. This note comprehensively introduces the research and design of this series of gallbladder endoscopes.     

机载电缆作战损毁后智能化诊断系统

从技战术实际需要出发,给出了某型飞机作战损毁后机载电缆的智能化诊断系统的硬件结构框图。根据硬件系统模拟开关组件的原理,定义了电缆的连接矩阵、测量矩阵以及断口的映像矩阵运算,给出了断头查找的算法。计算表明,系统可在20 min内完成一个循环的断头查找并给出故障定位。     

Explicit local buckling analysis and design of fiber–reinforced plastic composite structural shapes

Pultruded fiber–reinforced plastic (FRP) composite structural shapes (beams and columns) are thin-walled open or closed sections consisting of assemblies of flat plates and commonly made of E-glass fiber and either polyester or vinylester resins. Due to high strength-to-stiffness ratio of composites and thin-walled sectional geometry of FRP shapes, buckling is the most likely mode of failure before material failure. In this paper, explicit analyses of local buckling of rectangular orthotropic composite plates with various unloaded edge boundary conditions (i.e., (1) rotationally restrained along both unloaded edges (RR), and (2) one rotationally restrained and the other free along the unloaded edges (RF)) and subjected to uniform in-plane axial action at simply-supported loaded edges are first presented. A variational formulation of the Ritz method is used to establish an eigenvalue problem, and explicit solutions of plate local buckling coefficients in term of the rotational restraint stiffness (k) are obtained. The two cases of rotationally restrained plates (i.e., the RR and RF plates) are further treated as discrete plates of closed and open sections, and by considering the effect of elastic restraints at the joint connections of flanges and webs, the local buckling of different FRP shapes under uniform axial compression is studied. The approximate expressions of the rotational restraint stiffness (k) for various common FRP sections are provided, and their application to sectional local buckling predictions is illustrated. The explicit local buckling formulas of rotationally restrained plates are validated with the exact transcendental solutions. The analytical predictions for local buckling of various FRP profiles based on the present discrete plate analysis and considering the elastic restraints of the flange–web connections are in excellent agreements with available experimental results and finite element eigenvalue analyses. A design guideline for local buckling prediction and related performance improvement is proposed. The present explicit formulation can be applied effectively to determine the local buckling capacities of composite plates with elastic restraints along the unloaded edges and can be further used to predict the local buckling strength of FRP shapes.     

C语言中嵌套选择语句的逻辑关系浅析

本文介绍了如何用分析嵌套选择语句的逻辑关系，主要方法是借助分裂图画出N-S图，最后再根据IF…ELSE…语句配对原理分析出各子句的关系。     

迎接信息产业发展的第二个春天——''''98国家经济信息系统工作会议综述

５月的厦门，白鹭翩翩，春光灿灿。来自全国３０个省（区、市）、计划单列市、各信息协作网团体、各专业媒体的代表们从祖国的四面八方汇集到这里，参加’９８国家经济信息系统工作会议。与往年的信息系统工作会议不同，今年的会议有太多的背景可资评说。背景之一，本次会...     

酒钢3~#焦炉计算机加热控制系统

介绍了酒泉钢铁公司新建3#焦炉计算机加热控制系统的方案，硬件和软件配置；系统实际运行情况。     

基于矢量合成的平衡机最小可达剩余不平衡度测试方法的研究

通过对国标规定的平衡机最小可达剩余不平衡度评定方法的分析和研究，指出了该方法在原理和方法上所存在的问题，并且提出了一种全新的评定方法。这种基于矢量分析的新的评定方法能够快速、准确地计算出转子的最小可达剩余不平衡度，提高平衡机测试的准确性和现场测试效率，为更加客观地评价被测平衡机的综合性能提供了依据。