用非接触式电涡流传感器测量磁致伸缩系数

介绍了非接触式电涡流传感器的工作原理及用电涡流传感器测量位移的方法.在原有电阻应变法的基础上,用电涡流传感器代替电阻应变仪测量位移,改进和优化原有的硬件和软件.本测量仪与传统的电阻应变测量仪相比,能够整体直接测量稀土铁磁棒体材料的磁致伸缩系数,重复性好,可靠性高.     

基于光栅传感器的位移测量仪的研制

本文介绍一种基于光栅传感器的位移测量仪。它通过硬件电路对2个光栅传感器输出的信号分别进行20细分,然后对细分后的信号分别进行辨向和计数,再使用一个微处理器对辨向信号和计数信号进行处理,得到X-Y工作台在坐标X和坐标Y方向的位移值,最后根据误差修正算法对位移测量值进行修正,得到该仪器的测量分辨率为1μm且测量精度达±2μm(1σ)。此外,所研制的测量仪具有可靠、易于扩展和调试方便的特点。     

一种角位移测量仪的研制

介绍一种用于光学测量投影仪的角位移测量仪。它通过硬件电路对一个旋转编码器输出的角位移信号进行辨向和计数,再使用一个微处理器对辨向信号和计数信号进行处理,得到被测工件在Z旋转方向的位移值,最后对位移测量值进行误差修正,得到该仪器的测量分辨率为1’且测量精度为±3．9’。实验表明：所研制的角位移测量仪具有准确、可靠的特点。     

BSIA失真度测量仪稳定性浅析

在对电测量的各种检定装置电源进行检定的工作中，装置输出的失真度是一个必检的重要指标，规程对此已明确规定。而失真度测量仪本身的准确度及正确的操作，则是准确测量的关键。我室早在1990年就在全国电力系统中率先建立了失真度测量仪检定标准，开展对失真度测量仪的周期检定，从而保证了失真度测量仪的准确性。目前，我省系统内使用的失真度测量仪大多为北京无线电仪器厂生产的BSIA型失真度测量仪，这种失真度测量仪在同类产品中具有误差小、测量频率范围宽的特点，但也有许多不足之处，如笨重、体积大等，尤其是仪器测量时稳定性较差…     

基于图像识别的电力测量仪表计量误差校正技术

<正>电力测量仪表的计量精准度是满足电力企业收集电力信息需求的关键。针对计量误差问题，技术人员设计了多种校正技术。本文结合图像识别的技术优势，开发了新的电力测量仪表计量误差校正技术。1电力测量仪表计量误差校正技术设计1.1核定电力测量仪表计量的相位偏移在电力测量仪表计量的过程中，由于电压与电流的相位差，容易增加电容、电感计量的滞后性，影响误差校正效果。本文将电力测量仪表的有功计量偏差与无功计量偏差进行校正，     

光电式脉搏传感器及由其组成的血压测量仪

本叙述了光电式脉搏传感器的结构及工作原理，介绍了血压压力传感 及由它们组成的血压测量仪，该血压测量仪以ＭＳＣ－５１单片机为控制核心，用液晶显示器显示结果，测量仪具有体积小，功耗低，使用灵活等特点。     

6～35KV电网电容电流补偿失谐测量仪

６～３５ｋＶ电网电容电流补偿失谐测量仪俄罗斯有关杂志报道了人们关注的装有手动调谐消弧线圈的６—３５ｋＶ电网电容电流补偿失谐测量仪，介绍了失谐测量仪的结构原理。电容电流补偿失谐测量仪的结构如附图所示。图中包括：带有限制电平Ｈ的继电器网络１，加法器“＋”...     

便携式自由曲面曲率测量仪控制装置研究

针对自由曲面曲率测量的需要,本文设计了一种曲率测量仪控制装置,介绍了其设计原理,结构及测量方法。该控制装置主要由传感器、信号处理电路、ARM处理器、LCM显示4部分组成。根据空间几何性质推算出了任意曲面的曲率公式,采用容栅式位移传感器测量出所需要的量,通过电平转换电路,将数据送到ARM处理器,再由ARM处理器对数据进行相应的运算,最后由LCM液晶显示器把所测到的曲率显示在屏幕上。所设计的曲率测量仪具有体积小、测量精度高、操作简便的特点。     

便携式高速电气参数测量仪的研制

介绍并口EPP模式，设计了基于EPP模式的缓冲存储器扩展电路，并用于便携式电气参数测量仪中，实现PC机对缓冲存储器的高速读写操作和批量数据交换，给出了接口硬件电路和配套操作程序及实际测量仪框图。     

探析电测置仪表检修维护工作的基本规律和技术要点

结合电力系统常用电气测量仪表的检修、校验和安装工作，进行了经验总结，对照国家和行业技术规范和标准，提出电气测量仪表维护工作的一般要求，并对具体到某类型仪表的校验指出技术要点。     

Numerical Investigation of a Molecular Switch Based on Conformational Change, with the Inclusion of Contacts

We discuss the possibility of implementing a switch based on a conformational change, consisting in a relative rotation of a molecule containing two benzene rings, functionalized with proper substituents. Contacts are simulated with three-atom gold clusters, which are connected to the rest of the molecule via a thiol group. Relative rotation of the two rings, induced by a transverse electric field, determines a variation of the height of the potential barrier separating them, due to the change in the amount of conjugation of the π orbitals. The action of such a barrier is evaluated by computing the shift of the electron density as a function of a longitudinal electric field.     

典型半潜式平台结构的微振子捕能特性研究北大核心CSCD

半潜式平台在海洋资源开发领域应用前景广阔,但存在平台设备能源供给不足的问题。本研究把常见的半潜式平台简化为三种典型的浮式基础,将波浪能发电装置集成至浮式基础,建立浮式基础与浮子耦合的运动方程,利用水动力仿真软件AQWA开展数值模拟和参数化分析,获得了波浪方向、浮式基础的截面形状、浮子直径以及浮子与浮式基础间距等因素对浮子捕能特性的影响规律。结果表明,四棱柱浮式基础在特定波浪方向下能够增强微阵列浮子的捕能效果,三棱柱浮式基础使微阵列浮子更好地适应各个方向的波浪激励,圆柱浮式基础以遮蔽效应为主,较大程度上减弱了浮子的捕能特性;不同波浪方向对四棱柱浮式基础、三棱柱浮式基础周围的浮子影响较大,而对基于圆柱浮式基础的微阵列浮子影响不大;通过增加浮子的直径以及浮子距圆柱浮式基础的距离,能够有效提高微阵列浮子平均输出功率。本研究可为半潜式平台与波浪能发电装置的集成提供参考。     

换热器管壁圆形泄漏口空间辐射声场分布特征数值研究

根据可分离辐射源的声辐射，利用叠加原理和无穷级数迭代求和，建立了换热器管道壁面圆形口非分离泄漏声辐射源的空间声场分布数学模型。计算了圆形口均匀幅度非分离声辐射源的空间声场远场分布，给出了其远场相对声压级和位相的空间分布图案。与方形口均匀可分离辐射源的空间声场分布特征相比，发现两种情况具有相同的空间指向性特征，在较高频率时辐射声场空间分布出现盲区，在x—y平面内声场分布与泄漏口形状无关，但与辐射频率有密切关系。     

具有特殊地形条件的长距离供水工程水锤防护

在长距离供水工程中输水管道一般按地形走势布置。针对一些地形条件特殊的供水工程,本文提出了一种空气罐与出口溢流池联合设置的水锤防护方案,并建立了出口溢流池的数学模型。在空气罐体型一定时,给出了出口溢流池截面积的理论计算公式,有效地减小了在溢流池体型初期选取过程中的盲目性和工作量。结合某长距离输水工程,对比分析了空气罐和出口溢流池联合防护与单纯的空气罐防护对水锤的影响。结果表明空气罐与出口溢流池联合防护方案在前陡后缓的长距离供水工程中能够取得良好的水锤防护效果,且溢流池的溢流水位越高,其对负压的防护效果越好。     

Periodic steady-state solution of a synchronous generator based on a voltage-behind-reactance formulation and the Poincaré map method

A powerful blend based on a voltage-behind-reactance (VBR) model and the Poincaré map method, suitable to carry-out harmonic oriented analyses, is presented in this paper to compute the periodic steady-state solution of a synchronous generator. The VBR model, as originally conceived, is modified and instead a per-unit version, tailored to the acceleration procedure, is used. The acceleration of the convergence to the periodic steady-state is accomplished with a Newton method and the Poincaré map. A Numerical Differentiation approach allows the computation of the transition matrix involved in the acceleration procedure using a sequential perturbation of the state variables. The periodic steady-state solution of synchronous generators is reported for a set of operating conditions such as change of load, a three-phase fault and a single-phase fault. Furthermore, the harmonic analysis of a system comprising a RLC circuit with a varying degree of unbalance, fed from a synchronous generator is carried-out with the acceleration procedure. Important speedup factors up to 145 are reported for large turbine generators. The application of a Newton based acceleration procedure to a VBR synchronous machine model yields important benefits for the efficient computation of periodic steady-state solutions and it is particularly useful for test cases involving large rotary machines with an inherently large inertia.     

Inspection system for railway facilities using a continuously scanned image

A continuously scanned image (CSI) gives convenient image data for inspection of elongated facilities in railways, such as tracks, rolling stocks, and so on. We have developed a system named ConSIS to take the CSI at a high data rate of 40 M pixel/s. The system comprises a line-sensor camera and a data-recorder. As the result of field tests taking the CSI of tracks, rolling stock, and tunnel walls, the feasibility of an inspection system using the CSI was confirmed. Additionally, we have developed a prototype image database system to examine effective use of the CSI, in which useful functions, such as normalizing a scale of the CSI, scrolling a continuous image, and zooming a fine image for observation, are implemented. Further, we have developed a method to extract cracks on a concrete surface for automatic inspection using the CSI and a computer. © 1998 Scripta Technica, Electr Eng Jpn, 125(2): 52–64, 1998     

靶场光雷测量数据融合定位方法研究及应用

在靶场测量中,光电经纬仪由于测量直观、可靠性好、测量精度高等特点,一直被作为外弹道跟踪测量的重要设备,但是其不具备单站定位功能且双站交会受布站等因素限制。针对这种情况,为充分利用测量数据,将部署在经纬仪附近的具有作用距离远的雷达系统与光电经纬仪建立联合定位模型。首先对雷达和经纬仪的测量数据进行时间和空间配准,然后通过单站定位方法得到目标的位置。应用结果表明,其定位精度明显优于雷达单站定位精度,该方法可以作为计算弹道坐标的一种补充。     

Single transistor high linearity and wide dynamic range active inductor

In this paper, an active inductor (AI) with high linearity and high dynamic range, including a minimum number of components, is presented. The AI is composed by a single transistor, and by a passive compensation network; the latter allows the control of the values of both the inductance and the series resistance. In order to show the feasibility of the proposed AI for filter applications, a prototype board on a TLX8 substrate with a first‐order active band‐pass filter has been fabricated and tested. The filter has a center frequency of 2470 MHz (useful for Bluetooth applications) and a measured noise figure (NF) of 9 dB with a ?5 dBm P₁dB compression point, and a 75 dB dynamic range. Copyright © 2013 John Wiley & Sons, Ltd.     

A Fixed-frequency Series-parallel Resonant Converter with Capacitive Output Filter: Analysis,Design, Simulation,and Experimental Results

In this article, a fixed-frequency phase-shift-controlled full-bridge series-parallel (or LCC-type) resonant converter that uses a capacitive output filter is proposed. Steady-state analysis of this converter is performed by using a complex AC circuit analysis approach. Based on the analysis, a simple design procedure is given and exemplified with a design example of a 200- to 220-V DC input, 300-W, 100-V output converter. The relationship between the design parameters, switch stresses, and converter size is illustrated. Both computer simulation and experimental results on a lab prototype converter are presented to verify the performance of the designed converter for varying input voltage and load conditions. It is shown that this converter requires a narrow variation in pulse width for a wide variation in the load, while the peak current through the switches decreases with the load current. One typical application of this converter is for use as a second stage for AC-to-DC converters.     

Self-regulated self-excited brushless three-phase synchronous generator

For lightweight and compact implementation of a generation set, many attempts have been made by some researchers to develop a brushless self-excited synchronous generator without an ac exciter. A previous paper proposed a novel self-excitation scheme by which the second-space harmonic component of armature mmf is used for exciting the rotor field system. In this excitation scheme the effect of the series excitation characteristic, as well as a self-excited and brushless implementation without an ac exciter is automatically obtained. However, in the case of system configuration of the generator already reported, voltage regulation in the inductive load condition was very large. To remove this problem, this paper presents a new system configuration of the generator with a self-regulating feature that can compensate voltage regulation automatically. The new generator consists of a stator installing two three-phase windings, externally connected to a load and a capacitor bank, respectively, and a rotor with field and harmonic windings. In this paper the system configuration and theoretical concepts of the presented generator are described and detailed experimental investigations with a laboratory machine are also shown.