Development of three-electrode type micro-electrochemical reactor on anodized aluminum with photon rupture and electrochemistry

Photon rupture with a focused single pulse of pulsed YAG-laser irradiation was used to fabricate an aluminum electrochemical micro-reactor. Porous type anodic oxide film formed on aluminum specimens was irradiated in solutions with a pulsed Nd-YAG laser beam through a convex lens to fabricate micro-channels, micro-electrode, and through holes (for reference electrode, solution inlet, and outlet). During irradiation, specimens were moved by a computer controlled XYZ stage. After irradiation, the surface of the micro-channel and through hole were again treated to form anodic oxide film and the surface of the micro-electrode was treated electrochemically to provide an Au layer. The calculated volume of the micro-reactor including micro-channel and through holes is about 1.5 μl. The cyclic voltammogram of the micro-electrochemical cell was measured in K₃Fe(CN)₆/K₄Fe(CN)₆ with both static and flowing solution at different scanning rates. The anodic and cathodic peak currents were measured and the values depended on scanning rate and ion concentration when the solution was static. With the flowing solution, limiting currents were observed and the anodic limiting current was increased with the cubic root of the solution flow rate.     

基于最大后验概率的熔融态物料结构的层析图像提取法

以聚合物挤出过程中的熔融态物料为对象，在比较层析图像与反射式光强图像的成像特点基础上，叙述了基于最大后验概率的熔融态物料多特征结构的层析图像提取方法，并介绍了层析图像提取实验的结果，理论与实验表明，该方法能有效地分割熔融态物料，细化熔融态结构,实现对熔融态物料特征结构的提取和测量。     

开关电源高频变压器超声波测量装置设计

高频变压器是开关电源的核心元器件,在开关电源高频的趋势中,如何测量高频变压器的高频噪音成为业界所面临的棘手问题。提出一种开关电源高频变压器超声波测量装置,可以精确、便捷地测量超出人耳听觉范围的超声波,并通过微处理器处理分析测量信息后,在显示屏中得到所选定高频噪音频率段的平均功率等级。     

数控车床定位精度的激光检测法

数控机床的定位精度是反映数控机床控制特性和加工质量的重要指标,直接决定着零件的加工精度。如果机床的定位精度超差,则会导致加工出的零件不合格,这也直接影响了数控机床性能与功能的发挥。为了快速、准确检测出机床的定位误差并进行误差补偿,阐述了利用双频激光干涉仪进行数控机床定位精度检测的方法。     

EVALUATION OF A METHOD FOR MEASURING MIXING TIME USING NUMERICAL SIMULATION AND EXPERIMENTAL DATA

A method for measuring mixing performance in large-scale vessels is investigated. The method is evaluated experimentally in a pilotscale reactor and by using a model based on the three-dimensional calculation of the flow field. The method is based on injection of a tracer and measuring the concentration with several detectors at different locations. The mixing performance is measured as the decay rate of the difference between the concentration at the detectors and the final concentration.

The model predicts a strong dependence on injection point. The assumption of a first-order decay rate of the concentration deviation is more appropriate for some injection points.     

用激光技术测定液体中的声速和等熵压缩性系数

本文应用根据激光光声原理和技术建立的流体热力学性质测量实验装置，测定了七个温度下苯、四氯化碳液体中，苯与四氯化碳二元溶液中的声速（ｕ）、密度（ρ），计算了等熵压缩性系数（Ｋ＿ｓ）等热力学数据。用多项幂级数，以最小二乘法拟合声速ｕ与温度ｔ的数学关系。实测的声速值与文献值比较，相对误差小于０．０４％，等熵压缩性系数与文献数据也相当吻合。     

Measurement and modeling solubility of bioactive coumarin and its derivatives in supercritical carbon dioxide

To design a supercritical fluid extraction process for the separation of bioactive substances from natural products, a quantitative knowledge of phase equilibria between target biosolutes and solvent is necessary. How-ever, mostly no such information is available in literature to date. Thus in the present study, illustratively the solubility of bioactive coumarin and its various derivatives (i.e., hydroxy-, methyl-, and methoxy-derivatives) in supercritical CO₂ were measured at 308.15–328.15 K and 10–30 MPa. Also, the pure physical properties such as normal boiling point, critical constants, acentric factor, molar volume and standard vapor pressure for coumarin and its derivatives were estimated. By these estimated information, the measured solubilities were quantitatively correlated by an approximate lattice equation of state proposed recently by the present authors.     

Evaluation of nucleation activation energy in metal CVD processes

A new approach to evaluate activation energy for nucleation in metal chemical vapor deposition (CVD) is presented. Deposition is performed by laser induced chemical vapor deposition (LCVD) using a low laser power and a high scan speed, so that only discrete particles in the initial nucleation stage are formed. The nucleation activation energy is then obtained from a relationship between the laser-induced surface temperature distribution and the particle distribution. The activation energy is directly related to the nucleation barrier, and hence the difference in the nucleation activation energies on different substrates may be used to explain the chemical selectivity which is often observed during metal CVD processes. This approach is experimentally applied to aluminum CVD using dimethylethylamine alane (DMEAA) precursor, and its nucleation activation energy is found to be 25kcal/mol on silicon surface.     

浅谈汽车四轮定位检测与调整技术

四轮定位对汽车的正常行驶起着十分重要的作用。对汽车四轮定位参数进行检测和调整,不仅能确保汽车的正常行驶,还能延长轮胎的使用寿命,同时节省油耗。重点研究了汽车四轮定位的检测方法和调整技术。     

激光遥感图像高速滤波器算法的FPGA实现

针对激光遥感信号高速高精度的要求,利用FPGA的多任务、高速并行性设计系统进行滤波。考虑到激光光电传感器设计的滤波器会有很大的信号衰减,且具有精度要求高的特点,提出了基于 FPGA内部基本逻辑单元、乘法器、存储器,经过乘法分解和时序设计,实现具有可移植性的图像高速分辨的方法。系统采用FPGA设计平台,并用Verilog语言设计程序。试验结果验证,该滤波器对激光遥感信号具有高速、精确滤波功能,同时表明利用低端FPGA设计激光滤波器必将成为未来发展趋势。