快速凝固 Al-Fe 合金中准晶相的研究

在快速凝固Ａｌ－Ｆｅ－Ｖ－Ｓｉ合金棒材中发现了１种圆形准晶相,尺寸为０２～０５μｍ,成分为Ａｌ－８０ａｔ％Ｆｅ－２．１ａｔ％Ｖ－３．２ａｔ％Ｓｉ。对此准晶进行了透射电镜、Ｘ－光衍射结构分析,并对准晶的形成机制进行了讨论。     

J557GR 高韧性焊条的研制及应用

研究了碱性焊条工艺性的影响因素,探讨了焊缝金属的含氢量、焊条药皮的吸湿性、焊缝金属的强韧化特性等。在此基础上研制了高韧性、超低氢及操作工艺性优良的、适用于屈服极限为４００～４５０Ｎ／ｍｍ２级的低合金钢用Ｊ５５７ＧＲ高韧性焊条。     

论原子与原子能态

用原子负能态的物理基础论证了“正能态原子”概念的错误,对原子的光谱线系限外连续带的产生机理提出了新的观点．     

铜蒸气激光器的热设计

本文系统阐述了铜蒸气激光器的设计过程.在大量实验资料的基础上,给出了激光器放电管尺寸、输入功率密度的选择原则,通过分析放电管内气体温度分布、激光管径向热导损耗,建立了一套确定保温层厚度的方法.分析了光束"黑心"的原因,进而提出了解决途径.以上的设计思想在我们新近研制5W器件上得到验证.     

Generation of tunable, narrow-band mid-infrared radiation through a 532-nm-pumped KTP optical parametric amplifier

We report generation of broadly tunable (2.5-4 μm), narrow-band (0.04-0.35 cm-1) pulsed infrared radiation through a nanosecond optical parametric amplifier based on potassium titanyl phosphate (KTP) pumped by the second harmonic of a 10-Hz Nd:YAG laser. Input radiation at signal wavelengths of 615-662 nm was derived from a pulsed tunable dye laser system. Advantages of this device are simplicity, the broad range of infrared wavelengths to which a single dye in the dye laser provides access, and conversion efficiencies >10% at modest levels (<150 μJ) of input radiation.     

Estimation of optical constants of thin film by the use of artificial neural networks

A system for analyzing single-layer optical thin films has been formulated by the use of artificial neural networks. The training data sets stem from the computational results of the physical model of thin films, and they are used to train the artificial neural network, which, when done, can give values of film parameters in the millisecond time regime. The fast backpropagation algorithm is employed during training. The results of training are also given.     

Relationship between fracture parameters from two parameter fracture model and from size effect model

This paper studies the relationship between the two parameter fracture model and the size effect model. An equivalency between two models is first established based on infinitely large size specimens. Based on this equivalency, relationships between material fracture parameters (K _Ic ^s , CTOD_c) and (G _f, c_f) are derived. Using these relationships, values of (K _Ic ^s , CTOD_c) and (G _f, c_f) can be predicted from each other. It is found that the relationship betweenCTOD _c andc _f theoretically depends on both specimen geometry and initial crack length. However this dependency is numerically insignificant, except for tensile plate with a short center notch. The obtained results may explain why both the two parameter fracture model and the size effect model can reasonably predict fracture behavior of quasi-brittle materials.     

Roles of solution conductivity mismatch in transient current and fluid transport in electrolyte displacement by electro-osmotic flow

Electro-osmotically driven displacement between two solutions having a conductivity mismatch is theoretically examined. Internal pressures induced by the conductivity mismatch can affect the propagation of the solution interface and the behavior of the transient current. Combining Ohm’s law and fluid mass conservation, we derive a coupled set of length-averaged equations accounting for how the electric current and the traveling distance of the solution interface vary with time, electric field, and the solution conductivities. Extension to successive displacements involving multiple solution zones is made to reveal non-monotonic and stagewise changes in transient currents. For the first time, critical roles of surface conductance on displacements in highly charged channels are unraveled. We show that if the lower conductivity solution has a greater valence than the higher one, the effective conductivity of the former can exceed that of the latter when the channel height is below some critical value. The resulting transient current behavior can turn opposite to that usually observed in the large-channel case, offering a new paradigm for gauging the importance of surface conductance in submicron charged channels. Possible impacts of diffusion smearing and hydrodynamic dispersion are also discussed by including the additional mixing zone into the analysis. Having shown good agreement with the existing experimental data, our analysis not only captures the natures of solution displacement by electro-osmotic flow (EOF), but also extends the applicability of the current monitoring method for measuring surface zeta potentials of microchannels.     

Supporting rapid design and evaluation of pervasive applications: challenges and solutions

Along with the improvement of the key technologies for pervasive computing, the design of applications itself has emerged as a notable research area. A design should decide which features go into the application of supporting its context-awareness and ascertaining how well those features add value for users with an acceptable user experience. This paper initially identifies the challenges in designing and evaluating pervasive applications. It then presents a condensed survey of prototyping techniques and existing toolkits with the aim of understanding how the design issues have been addressed by research prototypes. At the end, we describe various open issues with suggestions of possible ways to extend the capabilities of current prototyping toolkits.     

基于机器视觉的高密度电路板缺陷检测系统

为减少高密度电路板的缺陷误报率,研究一种新型自动光学检测系统(AOI);系统采用自行研制的多色LED照明系统,利用机器视觉获取被测PCB的图像,通过图像处理软件系统快速准确地识别出各种缺陷;系统利用获取的彩色图像信息,根据各种缺陷的特征信息不同,采用OPENCV对各种缺陷的检测算法进行改进,使得系统性能有很大改进;对30块同类HDI型PCB的36300个检测点进行测试,测试结果证明,系统PCB缺陷的检出率高达99.87%,误报率只有0.32%。