基于虚拟仪器的指针式电测仪表自动检定系统

本文提出并设计了一种硬件结构简单的基于虚拟仪器的指针式电测仪表自动检定系统，介绍了系统的组成与工作原理，论述了检定数据修约、检定结果柱状图生成、用户数据库管理等软件设计方法。系统可按照电测仪表检定规程自动产生检定点，完成检定数据自动修约，显示、保存、打印检定结果，生成、打印检定证书，大大简化指针式电测仪表的检定过程，提高检定效率，消除人为误差。     

虚拟仪器技术及其发展

虚拟仪器技术是现代仪器技术与计算机技术相结合的产物。本文较为全面系统地介绍了虚拟仪器技术的发展，包括虚拟仪器的定义、虚拟仪器系统的构成、虚拟仪器的软件开发平台以及虚拟仪器技术的具体应用。     

三表检定的不确定度评定

采用交直流标准源作为主标准器来检定模拟指示式电流表、电压表和功率表(简称三表)是目前三表检定的主要方法。本文分析了检定过程中的不确定度并给出了交直流电流、电压、功率的不确定度评定方法。     

A Self-Balancing Digital Differential Voltmeter Based on the Direct-Current Comparator

The differential voltmeter described is based on the dc comparator, so that the voltage adjustment is made by varying turns and not by selecting taps on a resistive divider. The linearity errors are, therefore, permanently less than one least significant digit. One, ten, hundred, and thousand volt ranges with impedances of 1000 ?/V are provided; also provided are high-impedance ranges of 1-10 V. Either positive or negative voltages may be measured. On all except the 10-V high-impedance range, there is a 60-percent overrange capability. The method of automatically converting the analog-input signal to a digital display, the main sources of error, and the techniques and components used to keep the error less than one least significant digit are discussed.     

基于智能手持设备的光照度计虚拟实验程序的设计与实践

为了降低传统桌面虚拟实验系统对场地、设备的需求,克服光照度计计量教学资源短缺的现状,设计并实现了基于智能手持设备的光照度计计量虚拟实验程序以满足光照度计计量教学的需要。以智能手持设备为载体,采用Multi Gen Creator软件进行实时场景建模,依托Unity 3D软件为开发平台,采用C#脚本语言来完成已建立的3D模型和场景的交互与编辑,通过Vuforia软件实现了增强现实功能。实验证明:该程序优化了教学资源,能够很好地满足光照度计计量教学的需要。     

LF Adaptor Extends Vector Voltmeter Magnitude and Phase Measurements down to 10 Hz

An IC single-sideband modulator is described that allows direct measurement of magnitude and phase of a voltage over 3 decades anywhere in the range 10 Hz to 1 MHz. Two modulators generate a leveled upper-sideband (USB) reference signal about a 1-MHz suppressed carrier acceptable to the HP 8405A vector voltmeter. Another modulator produces a double-sideband (DSB) replica of the output voltage of the test device. The vector voltmeter then measures the magnitude of the upper-sideband reference and test device signals and their phase difference.     

四声道超声波气体流量计硬件电路设计

介绍了超声波流量计的工作原理,设计出一种简单高效的四声道超声波驱动电路及回波接收电路,着重介绍了四声道电路切换的设计。信号接收电路采用集成芯片放大滤波。本系统主要应用于超声波气体流量计。最终实验结果表明发射效率高,同波信号良好。     

基于LabVIEW的宽频带电压表自动检定系统模拟器设计

根据宽频带电压表自动检定系统相关理论,在计算机的控制下,采用面向对象的可编程语言LabVIEW,设计了宽频带电压表自动检定系统模拟器,模拟宽频带电压表自动检定系统的工作过程,根据计量检定原理以及计量检定规程,实现了宽频带电压表电压刻度误差和频率附加误差的自动检定。系统选用目前国内外最先进的电压标准组合,建立频率范围从10Hz～1.2MHz,电压范围从（0～1100）V,分辨力1μV的低频电压标准量值和频率范围从10Hz～2GHz,电压范围从0.2～2V,测量不确定度为0.6%～1.5%的高频电压标准量值,提高了电压参数自动化测试水平。     

基于同态滤波的仪表图像识别方法

针对仪表面的玻璃反射造成后续处理的仪表参数缺失,提出了基于同态滤波的图像分割方法。用减影法提取出指针、刻度,进行并串结合的细化处理,用距离法判别出读数。实验证明,该算法分割效果好、实用性强,为准确判定指针位置和计算指针读数奠定了基础。     

巧用单相电能表校验装置检三相四线有功电能表

本文主要介绍用单相电能表校验装置检定三相四线电能表的方法。     

基于虚拟电能表技术的用电信息采集系统检测装置设计

针对用电信息采集系统缺乏相应检测设备的情况,设计了基于虚拟电能表技术的用电信息采集系统检测装置,论述了用电信息采集系统检测装置的技术方案和总体结构,详细介绍了主要功能模块单元的工作原理,并针对考核集中器抄读历史数据耗时太长等问题提出了虚拟电能表模块技术的测试方法.实践证明:基于虚拟电能表技术的用电信息采集系统检测装置能...     

阶跃阻抗谐振器结构的双频差分天线

提出了一种采用阶跃阻抗谐振器(SIR)结构设计的同轴馈电双频差分天线.天线具有对称结构,其传输线模型包含两个谐振单元.通过对谐振单元的简化和分析,证明了谐振单元类似于标准的1/4波长SIR,并导出了谐振单元的电长度和阻抗比与双频天线工作频率的关系.依照该方法设计了一个2.4/5.2 GHz的双频差分天线,同时用模型仿真...     

基于虚拟仪器的虚拟包装实验室构建

阐述了目前高校包装实验的教学现状,论述基于虚拟仪器构建虚拟包装实验室的可行性,详细介绍系统的硬件结构和软件模块.指出基于虚拟仪器进行实验教学将会成为包装实验教学的发展趋势.     

基于可持续设计理念的停车收费咪表设计

目的运用"从摇篮到摇篮"的设计方法对停车收费咪表进行设计与研究,以期促进现代城市交通的可持续发展。方法通过对"从摇篮到摇篮"的设计方法和原则的探讨,结合停车收费咪表的设计案例,分析了停车收费咪表可持续设计的策略和方法,并对停车收费咪表的设计进行了评价。最后,对停车收费咪表的可持续设计与研究进行了总结和展望。结论通过对停车收费咪表设计案例的研究,在城市停车设施特别是停车收费咪表系统中实施可持续性设计具有光明的前景。     

四米槽式太阳能真空集热管镀膜设备的发展概述

本文主要介绍了制备四米槽式太阳能真空集热管的间歇式单体镀膜机和自动连续镀膜线,对两种类型设备的优缺点和存在的问题进行了对比分析,可以为其他行业镀膜设备的设计改进提供借鉴.     

Instrumentation and Measurement of a Power Distribution System Laboratory for Meter Placement and Network Reconfiguration Studies

At Drexel University, instrumentation and measurement of the reconfigurable distribution automation and control laboratory include hardware and software instruments which together form an automated measurement and control system. This system contains special features that were included to enable meter placement and network reconfiguration studies. This paper presents an outline of the measurement and control system for the general laboratory and then focuses on the capabilities purposely added for the meter placement and network reconfiguration studies.     

Low Force Measurement Based on Impedance of a Piezo-resonator

Piezoelectric transducers have effectively been used for force measurement due to their inherently large stiffness. The primary transduction parameter of piezoelectric transducer is voltage which is used mostly for dynamic and sometimes for quasi-static force measurement. Other parameters of piezoelectric transducers such as resonant frequency, electrical impedance, etc. have also been used for force measurement. In the present work, precision measurement of conductance of a radial mode piezo-resonator has been carried out under different static loading and the resultant change in resonant conductance of the resonator have been evaluated as a function of loading force. This method based on resonant conductance measurement can prove to be effective in measuring forces between two interfaces which is an important requirement in many scientific and technical problems.     

Paragraph Vector Representation Based on Word to Vector and CNN Learning

Document processing in natural language includes retrieval, sentiment analysis, theme extraction, etc. Classical methods for handling these tasks are based on models of probability, semantics and networks for machine learning. The probability model is loss of semantic information in essential, and it influences the processing accuracy. Machine learning approaches include supervised, unsupervised, and semi-supervised approaches, labeled corpora is necessary for semantics model and supervised learning. The method for achieving a reliably labeled corpus is done manually, it is costly and time-consuming because people have to read each document and annotate the label of each document. Recently, the continuous CBOW model is efficient for learning high-quality distributed vector representations, and it can capture a large number of precise syntactic and semantic word relationships, this model can be easily extended to learn paragraph vector, but it is not precise. Towards these problems, this paper is devoted to developing a new model for learning paragraph vector, we combine the CBOW model and CNNs to establish a new deep learning model. Experimental results show that paragraph vector generated by the new model is better than the paragraph vector generated by CBOW model in semantic relativeness and accuracy.     

基于TRIZ理论的微欧计创新设计

目的从微欧计的结构和工作原理出发,采用先进的TRIZ创新方法理论,对现有的微欧计进行创新设计,达到提高精度和自动化程度、降低控制系统的复杂性的目的。方法采用TRIZ工具的技术矛盾工具,通过查找矛盾矩阵表和应用发明原理解决测量控制方案复杂的技术矛盾。采用物场分析的工具,建立物场模型,找到对应的标准解法,得出自动化程度不高的解决方案。结果通过TRIZ理论的技术矛盾和物场分析理论,实现了微欧计自动量程切换且保证相对误差在±0.1%读数±5个字的标准。结论利用TRIZ理论的矛盾分析理论和物场分析理论能找到产品创新设计方案,使微欧计精度更高,控制系统更简单,制作成本更低,自动化程度更高。     

采用特性阻抗匹配的半主动组合吸声材料与结构

由于主动吸声在低频声波入射时方有吸声效果,而在中高频声波入射时,吸声效果不明显。鉴此,采用一种新的半主动吸声方法;即由一层吸声材料和可移动的刚性壁组合结构,改变刚性壁移动的速度,使吸声材料的表面声阻抗与空气的阻抗相匹配,从而使吸声材料的吸声系数达到最大。最后,对平面入射声波进行了数值计算与实验,结果表明：在100～2 000 Hz时,吸声系数能达到0.8～1.0,而对于更高频率的入射声波,用此方法进行纯主动吸声的效果改善不明显。