悬停直升机的雷达探测技术

首先对直升机旋翼的雷达回波进行建模与分析,在此基础上分析了雷达探测悬停直升机的可能性,提出了一种适用于所有直升机类型的多扫描周期积累检测系统方案,讨论了可能影响其检测性能的因素.     

前向反冲分析和非卢瑟福背散射

介绍了弹性散射分析中的另外两种分析方法——前向反冲分析和非卢瑟福背散射分析。前向反冲分析适用于材料中H和He同位素分析。高能质子和He离子背散射分析可提高对重基体中C,N和O等轻元素分析的灵敏度。给出了这两种分析方法的应用实例。     

Voltage sag compensation with minimum energy injection by use of a micro‐SMES

This paper presents a method to compensate voltage sags with minimum energy injection for a series‐connected voltage restorer using a micro‐SMES. A circuit for extracting the fundamental symmetrical components from sag voltages and a minimum energy injection algorithm is described. Simulations of voltage sag compensation have been carried out using PSCAD/EMTDC for various faults. The simulation results confirm the validity of the proposed method and show the possibility of reducing the size of energy storage devices. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(3): 70–80, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10047     

钻井液用BDY-1便携式堵漏仪

在堵漏过程中，对堵漏材料和堵漏浆配方的优选是决定堵漏成功的关键。为了能在现场对堵漏进行评价，研制出BDY－1便携式堵漏仪，该堵漏仪主要由不锈钢钢柱圈钢，压力表等加工而成，该堵漏仪体积小，重量轻，价格低，仅为国产堵漏仪的1／20。试验结果表明BDY－1便携式堵漏仪操作简便，可快速对堵漏材料进行评价并筛选出堵漏配方；数据重复性好，准确可靠，能达到进口或国产堵漏仪的水平；在模拟漏层选定后，可采用多套压力梯度，对堵漏浆封堵效果进行评价，在压力梯度选定后，可评价堵漏浆对不同类型漏层的封堵效果；如果扩大压力范围，可对封堵后的漏层进行破裂试验，从而确定合理的钻井施工参数；适用现场操作和应用。     

引进综采设备常用渐开线花键的标准及计算

根据煤矿引进的综采设备中采用不同标准渐开线花键的特点 ,提出了综采设备常用渐开线花键的测量与计算     

Use of radial forces for fault detection in tapping

A model-based method for fault detection in tapping based on torque and radial forces is proposed. The method allows the identification of faults typical of a tapping operation including axial misalignment, tap runout, tooth breakage both singly and together. The validation experiments have been run on aluminum 356 workpieces for different combinations of process faults. Results have shown that the model predictions are in good agreement with the experimental radial force and torque signals under various fault conditions.     

流量自动控制的设计与实现

文章通过分析多相流模拟井的实际工作要求 ,提出了简单实用的流量自动控制模型。应用成型的计算机数据采集和控制模块及稳定可靠的流量控制部件 ,实现了各相流量的自动控制过程。该流量自动控制系统调节精度高、速度快、整体造价低 ,在实际应用中取得了良好的效果。     

基于显微视觉的宏/微双重驱动微动台的自动标定

提出了基于压电技术的微操作系统的自动标定方法,采用混合式步进电机直接驱动的宏动平台,实现系统大行程宏动定位,安装在宏动平台上的压电陶瓷驱动的微动平台和精密光栅,实现亚微米级的分辨率和定位精度,通过以上两部分实现定位机构的全闭环反馈控制,采用显微视觉反馈获取微动台操作器在图像中的位置信息进行标定。实验结果表明:系统的动态和稳定性能良好,自动标定运算速度快,运行速度达到11 frame/s,实现了对系统的精确标定,标定精度达到0.1μm。     

Conceptual damage-sensitive features for structural health monitoring: Laboratory and field demonstrations

The use of damage-sensitive features to evaluate structural condition or health is a very critical aspect of structural health monitoring. The purpose of this paper is to investigate the potential of two different damage-sensitive features for detecting damage. Different damage scenarios are simulated on a large-scale laboratory structure and a three-span highway bridge for demonstration. The features presented in this paper are the modal flexibility-based deflection and curvature both of which are obtained directly from dynamic properties. In the literature, flexibility associated with mode shapes and mode shapes curvatures have been mostly explored. In this study, multi-input–multi-output dynamic data are used to obtain modal flexibility, which is a close approximation to the actual flexibility. A main novelty is that the curvature is calculated from the deflected shapes using the modal flexibility as opposed to using modal vectors. In this paper, the theory of the methodology is explained and then experimental studies and results are presented. For the experimental studies, the laboratory specimen and the three-span bridge were gradually damaged. It is shown that both deflection and curvature are conceptual and physically meaningful features for damage detection and localization. The issues and the requirements for these features to perform successfully are also presented.     

智能电动机控制器在电收尘通风机上的应用

对智能电动机控制器的情况作了介绍，结合工作实践提出了维护要点和建议，并对该控制器的参数设置进行了说明，这对使用该设备的工业企业有一定的指导意义。