离线用线缆计米器校准方法研究

随着国家对定量包装商品净含量监督力度的加大 ,全国各地市质量监督部门依据ＪＪＦ１０７０ -２０００《定量包装商品净含量计量检验规则》的要求 ,陆续配置了用于测量成卷电线电缆长度的计米器。质监部门和部分线缆生产企业出厂检验用的计米器 ,通常由测长仪表和绕线装置两部分组成 ,离线使用 ,以绝对法测量被测件的长度。测量原理如下图所示 :在测量轮同轴处 ,装上一只等分分度盘（遮光盘）和光电编码器 ,与线缆同步运动。光电编码器接受的每个脉冲与一定长度线缆相对应 ,即线缆长度等于脉冲乘以综合系数 ,可以通过读数装置直接读出。测量…     

一种线缆计米器在线校准的新方法

本文介绍了一种能准确、快捷地对线缆生产企业使用的计来器进行在线校准的新方法     

线缆计米器非接触式在线校准

<正>0引言线缆计米器(以下简称"计米器")作为线缆生产企业用于测量电线电缆长度的计量器具,一般是接触式计米器,其种类很多,有带压紧轮防滑装置的计米器、带印字装置的计米器等,尤其在生产线末端用于定量包装的计米器对企业至关重要。计米器的准确度受测量轮的磨损、打滑、线缆外套材料、线缆张力、人员操作等因素影响,计量技术机构对     

线缆计米器检定方法及注意事项问题探讨

本文介绍了线缆计米器的工作原理和线缆计米器的检定方法,分析了线缆计米器误差产生的原因,提出了线缆计米器计量检定中的注意事项,为计量同行提供参考。     

线缆计米器的检定方法及误差分析

本文设计了线缆计米器的检定方法及误差分析,以此规范和保护线缆计米器使用者及生产者的行为和利益。     

JJG 987-2004《线缆计米器检定规程》的探讨

0引言JJG987-2004《线缆计米器检定规程》(以下简称"规程")施行已有6年,规程中对线缆计米器(以下简称"计米器")的介绍,以及对测量轮直径差、读数装置示值误差变动性检定的规定等存在着问题,易导致检定人员在具体执行中产生疑问。笔者作为     

标准线缆计米器的研究

JJG 987-2004《线缆计米器国家检定规程》根据线缆计米器的准确度不同,把线缆计米器分为标准计米器和工作计米器两种,标准计米器可以作为标准器用来检定工作用计米器,使用标准计米器作为标准器可以更方便,效率更高的检定生产线上的工作计米器,大大减少生产线的停工、停产时间。本文中研制的一种新型履带对压线缆计米器,可以更好的解决线缆打滑、折弯问题,同时采用编码器作为传感器,有效的提高了计米器的分辨力。     

线缆计米器误差原因分析及消除办法

高速自动成圈型线缆计米器（以下简称“计米器”）目前广泛应用于电线及小截面电缆的生产。对线缆生产厂家来说，计米器是线缆成圈的生产设备．又是对电线电缆长度进行计量的重要器具。计米器计量准确与否将直接影响到定量包装线缆的计量准确性。自JJG987—2004《线缆计米器》检定规程实施后，笔者通过对各种类型的计米器的观察和分析．结合其工作原理以及分析．计量误差产生的原因提出了相应的消除方法，供大家参考。     

激光计米器垂直对准装置的设计

激光计米器测量应用的准确度要达到0.05%,其安装定位尤为关键。在确定安装距离后,需控制仪器定位的垂直角度偏差在1°以内。针对安装定位的要求,本文设计了一款对准装置,其垂直定位测量的测量不确定度可达0.04°,能确保仪器测量应用的准确度。     

医用吸引器校准方法研究

文章从医用吸引器的计量特性、校准项目和校准方法及校准结果的处理等方面对医用吸引器的校准进行了研究探讨。     

A hybrid method for calibrating acoustic arrays

A method to calibrate the elements of large arrays devoted to underwater applications is presented. The goal is to measure the sensitivity and directivity of the elements over their full bandwidth. The main constraint comes from the bounded geometry of the experimental setups that limits the duration of the time windows available for analyzing the received signals. Using a short wideband pulse is detrimental to obtaining high signal-to-noise ratios. A classical method for handling this problem is time-delay spectrometry (TDS), which is based on the transmission of a linear frequency- modulated signal combined with a sliding frequency filter. An alternative, hybrid method based on the transmission of a sequence of time-frequency-limited signals is proposed. This hybrid method is shown to provide the same spectral density as TDS in the frequency scanning, but the filtering process is quite different. The transmitted signals are designed to take advantage of the coherent sums of the received signals to track the time of flight of the direct paths between the source and the elements. In addition, a fitting process based on the calibration geometry of data acquisition enables the boundaries of the interference-free time windows to be precisely delineated. An example of the application is described.     

A new definition of the rainflow cycle counting method

A new equivalent definition of the rainflow cycle counting method is presented, which expresses the rainflow cycle amplitudes in explicit analytical formulae. The method attaches to each maximum of the strain function the amplitude of a corresponding cycle or two half cycles, which are evaluated independently from each other. This definition is more convenient for the statistical analysis of rainflow cycle amplitudes for a random loading process.     

一种新型的碎石料检测统计方法

为提高工业设备中石料级配的效率和经济性,文章提出了采用图像处理方法检测混合石料中大小石比例的思路,用于调节连续投料设备的石料配比。文章在总结碎石图像基本特征的基础上,提出一种基于边缘检测、边缘生长和倾侧光照的图像处理方法,实现了碎石料的边界分割与特征参数估计。此技术有望替代传统的碎石筛分方法,从而提高工业设备的性能,降低石料级配的成本。     

A new method of calibrating strain release coefficients in measuring welding stresses

The measured values of welding residual stresses often exceed material yield strength (σ_y) or tensile strength (σ_t), in measuring welding residual stresses in the welded joints of low carbon steel or stainless steel by drilling a blind hole. It is quite evident that measured values do not represent reality. Local plastic strain caused by residual stress concentrations round the blind hole has a main effect on the measuring error of welding residual stresses. This article presents a new method of calibrating strain coefficients A and B for eliminating influence of local plastic strain. In calibrating strain release coefficients A and B, calibrating stresses applied on the specimen were increased so that material round the blind hole produced local plastic deformation, ie coefficients A and B contained a component of the plastic strain. Numerial values of coefficients A and B were classified into four grades. Every grade coefficient contained a different quantity of the plastic strain for offseting the influence of the plastic strain round the blind hole. Test results have proved that by adopting these coefficients more satisfactory values for residual stresses can be obtained in practical engineering. The measuring average error in stainless steel (1Cr18Ni9Ti) reduces from 109% to 1.52%. The measuring average error in low carbon steel reduces from 54.69% to 3.21%.     

Technology for long cable erection of a thousand meter scale cable stayed bridge

In the background of the constrction of Su-tong Yangtze River bridge, the cable construction method and techniques of a thousand-meter scale cable-stayed bridge are introduced. Some key construction techniques, such as outspreading cable on deck, installing cable at pylon, pulling and fixing cable at the attachment with decks and cable PE protection, are discussed.     

千米级斜拉桥长索架设技术

以苏通长江公路大桥为饲介绍了千米级斜拉桥斜拉索安装方法及其施工要点.论述了斜拉索的桥面展开、塔端挂设、梁端牵引锚固以及PE保护等长索安装施丁的关键技术问题.长索桥面的展开采用立式放索,梁端牵引锚固采用卷扬机、钢绞线以及张拉杆共同组成的三级组合牵引方式,长索张拉在梁端进行.     

一种新型机车动轮弛缓在线监测及报警方案

本文介绍了一种新型机车制动热抱弛缓在线监测方案。该方案以轮箍温度及轮箍和轮辋的相对位移为对象，在线监控机车运行状态，提示司机机车的意外情况，确保机车行车安全。     

A new method of on-line multiparameter amplitude analysis with compression

An algorithm of on-line multidimensional amplitude analysis with compression using fast adaptive orthogonal transform is presented in the paper. The method is based on a direct modification of multiplication coefficients of the signal flow graph of the fast Cooley-Tukey's algorithm. The coefficients are modified according to a reference vector representing the processed data. The method has been tested to compress three parameter experimental nuclear data. The efficiency of the derived adaptive transform is compared with classical orthogonal transforms.     

A method for calibrating the line-focus-beam acoustic microscopy system

Absolute accuracy of the line-focus-beam (LFB) acoustic microscopy system is investigated for measurements of the leaky surface acoustic wave (LSAW) velocity and attenuation, and a method of system calibration is proposed. In order to discuss the accuracy, it is necessary to introduce a standard specimen whose bulk acoustic properties, (e.g., the independent elastic constants and density) are measured with high accuracy. Single crystal substrates of gadolinium gallium garnet (GGG) are taken as standard specimens. The LSAW propagation characteristics are measured and compared with the calculated results using the measured bulk acoustic properties. Calibration is demonstrated for the system using two LFB acoustic lens devices with a cylindrical concave surface of 1-mm radius in the frequency range 100 to 300 MHz.