计算机控制的SEESR实验系统的研制

SEESR(Simultaneous Electrochemical ESR)是研究电极过程中的自由基中间体行为的理想和方便的手段。在以前研制的ESR仪数据系统的基础上,我们应用IBM-PC/XT微机与JES-FE1XG型(JEOL产)ESR谱仪及HDV-7型恒电位仪研制了一套由计算机控制的SEESR实验装置。该系统可以完成包括循环伏安法、电流阶跃、电位阶跃及电位反转等多种电化学方法的SEESR实验。系统还具有包括数据平滑、曲线拟合等功能的多种数据处理软件,使用方便。我们应用模型化合物对该系统进行了实际测量,所得结果与文献报道一致。     

ZS1756振动筛动态分析

应用ＳＡＰ５Ｐ软件计算矿用振动筛前４０阶固有模态，从提高寿命观点看，第１阶，第３－４阶和第６阶模态应采取抑制措施；从队噪观点看，前６阶模态应给予注意。     

一种六辊矫直机电气控制系统设计

根据六辊矫直机的工程实例,结合矫直机的控制工艺以及控制特点,介绍了六辊矫直机控制系统的设计方法以及自动控制系统的实现方法;使用西门子S7-300PLC进行自动控制,对西门子MM440变频器进行PROFIBUS组态,以及通过西门子DI模块对绝对值型脉冲编码器的数据进行读取;解决了矫直机设备的自动运行与矫直速度的实时监控,以及上下辊间距的精确测量的问题;实验结果表明,控制系统运行稳定,辊间距测量精确无误,增加了矫直控制的精确性和稳定性,实现棒料矫直的自动化生产。     

Top-Down方法在成型模具设计中的应用

介绍模具Top—Down设计的基本思想、设计流程及其主要特点，并基于Pro/Engineer软件平台，以一鞋楦模具为设计对象，例示出模具Top—Down设计方法的主要设计过程。采用先进的Top-Down模具设计方法可以帮助设计者提高设计速度，避免一般设计中容易发生的错误，降低设计制造成本，加快交货期限。     

3D打印模型切片及路径规划研究综述

3D打印包括建模、分层切片、路径规划及打印等过程。对3D打印中三维模型数据处理技术核心--切片和路径规划进行综述。介绍3D打印切片软件中针对单材料不同格式的模型切片处理方法,阐明了3D打印中的不同工艺参数影响下的切片算法,包括各类分层切片算法和扫描填充算法,说明每种算法的优缺点,并对现有的单相均质模型切片算法进行对比分析与评价,总结模型切片处理算法的不足,提出改进方向以及未来研究多材料3D打印模型数据处理的切入点。     

A code-pattern-driven digital background calibration technique for SAR ADCs

The article presents the buck converter for the application on headlights of vehicle with chip-level design. The LED components are used as for lighting source, which near/far lights are controlled with high-current switching circuit in the chip. The level-shift circuit and its current driver is proposed to control the input of high-voltage power MOS. The bypass method is presented to reduce the transient time as load current changes suddenly. The input voltage widely ranges from 8 to 21 V while keeping a stable output voltage with 6 V. The chip current can output from 20 to 1500 mA with excellent regulation. This chip had been implemented with TSMC0.25 µm HV- process, and the size of the circuit layout is about 8.6 mm², where includes power switch and far/near lighting switches. Measurements show that peak efficiency can achieve 86.3%. The power regulation is excellent, where the load regulation is only 0.3%, and the line regulation is only 0.5%.

     

蜂窝网中协作定位技术

蜂窝网中的协作定位技术作为一种高性能的定位技术,改善了非视距传输(Non Line of Sight)和多径效应对移动终端(Mobile Station)定位的影响,扩展了定位服务范围。文中综述了协作定位技术原理与蜂窝网中协作定位技术的研究现状和应用,对现阶段的协作定位技术进行了分析比较,并展望了其发展方向。     

Feasibility study of the application of voltage contrast to printed circuit board

Voltage contrast (VC) has been a powerful tool for the failure analysis of integrated circuits and multichip module. As the packing density of printed circuit board (PCB) is increasing, conventional failure analysis methods to detect open or short circuit in PCBs are no longer adequate, and voltage contrast method could be a method for this purpose. However, unlike the cases of integrated circuits and multichip module, there are many areas in PCB that will produce serious charging effect when examine under the scanning electron microscope. One of the areas is the presence of solder mask on PCB.This work examines the feasibility of using voltage contrast for PCB failure analysis. Specially designed PCB is used for experimentation, and it is found that positive bias on one track and zero bias on another copper track provide a better image contrast as compared to negative and zero biases on the tracks. Also, the variation of the image contrast with different spacing between inter copper tracks has studied. It is found that the variation depends on the presence of solder mask and its location. The variation can be very different for negative bias case as compared to the positive bias case.Finite element analysis is also performed to explain the experimental observations. All the observations can be well explained by the charging effect of the solder masks. The charging effect of solder mask is indeed very significant in affecting the image contrast, and it could reduce the contrast to almost zero in some cases.     

振动筛振动方向角的调整

建立振动筛力学模型和运动微分方程，推导出振动方向角的表达式，通过分析影响振动方向角的因素，提出振动方向角的调整方法。     

电晕离子流对先导放电路径的影响

为探明当空气中含有电晕产生的离子时(离子背景),对雷电先导的发展、击穿过程和路径的选择有何影响,分别采用两种不同的实验方法研究了正、负离子流对先导放电进展路径影响的特点及规律,两种方法得出的一致结果表明,有离子背景的雷电先导放电路径具有选择负离子背景而回避正离子背景的特点和规律并运用电子崩发展和电场作用两方面原理,分析了离子背景的影响机制。这对于特高压输电线路与设备的防雷及其绝缘设计的进一步研究具有重要参考意义。