LabView在数字心电图机计量检定中的应用

数字心电图机是临床使用最广泛的、心脏疾病相关的检测设备。现行使用的数字心电图机检定规程,通过给心电图机一个已知信号,测量其描记的信号幅值,与已知信号对比,从而确定心电图机波形识别能力是否合格。检定过程中,测量所描记心电信号的幅值时,由于测量精度高且数据繁杂,通常要花费检定员很长时间。本文主要研究通过LabView的图像处理技术,对心电图机描记的波形幅值实现更方便、更快速、更准确的测量和计算。     

心电图机的计量检定体会及建议

实时测量人体表面心脏电位的模拟单通道、多通道心电图机的计量检定须按照JJG543-2008《心电图机》检定规程进行。而具有非线性系统及信号处理和用于特殊用途的心电图机(如数字心电图机、向量心电图机等)应根据各自具体情况进行检定。一、心电图机检定中应注意的问题由于心电图机的灵敏度较高,因此检定前一定要做好准备工作,检定过程中要规范操作,避免由于检定工作的错误影响对检定结果的判断。1.做好常规检查。其生产厂名、型号、出厂日期、编     

数字心电图机检定中常见问题探讨

一、数字心电图机的主要检定方法1.内定标电压内定标电压是数字心电图机的一个重要指标,在日常检定中,若内定标电压波形幅度出现按指数规律衰减甚至锯齿状,通常是滤波器接入所致,可断开滤波器后进行内定标电压的检定。2.输入电压范围输入电压范围是被检心电图机所能检测的输入信号的最小值和最大值。在日常检定中发现,滤波器接入时所显示的幅值偏小。     

光电数字心电图机计量检定心率不显示问题的探讨

正一、现状分析及存在的问题针对数字心电图机的检测,目前国内大部分计量技术机构采用的是由呼和浩特市某计量技术研究所生产的EGC-2011智能心脑电图仪检定装置。数字心电图机的检定依据是JJG1041-2008《数字心电图机检定规程》,规程6.3.11对心率测量误差的检测方法做了详细的介绍,调节信号发生器输     

心电图机检定的测量不确定度评定

心电图机的检定,是由一函数信号发生器通过有关人体参数模拟电路和导联选择网络（三者组成心脑电图机检定仪）,产生检定所需要的标准幅度信号和频率信号,由被检心电图机记录描记。其测量不确定度的评定主要从电压幅度（定标电压）和信号频率（走纸速度）两个方面分别进行。一、定标电压的测量不确定度评定（一）数学模型、方差及传播系数被检心电图机定标电压误差为：e＝Ud-Uo因为U＝kh所以e=k（hd－h0）式中：Ud——被检心电图机定标电压的显示值;Uo——检定仪输出标准电压在被检心电图机上的描记值;k——被检心电图机的灵敏度;h＿…     

心电图机内定标电压示值误差测量结果的不确定度评定

本文针对国内广泛使用的内蒙古计量所生产的EGC-1B心脑电图机检定仪，在检定心电图机内定标电压示值误差时的不确定度评定方法进行了探讨，并系统地研究了影响测量结果的各分量及函数传递关系，得出了典型心电图机内定标电压示值误差不确定度。可供从事心电图机检测工作的相关人员参考。     

心电图机时间常数检定方法的分析

<正>模拟心电图机的检定依据JJG543-2008《心电图机检定规程》,数字心电图机的检定依据JJG1041-2008《数字心电图机检定规程》。这两个规程中,心电图机时间常数的检定从表述和具体操作上差别较大,但实质上是否相同呢,本文对此作较为详细的分析。一、时间常数检定在两个规程中的表述和操作在JJG543-2008中,时间常数的检定方法如下:检     

心电图机计量检定的几点体会

自1996年我院建立心电图机检测标准以来，我们每年都对全院心电图机进行年度计量检定。目前，我院使用的是内蒙古计量测试研究所研制生产的98新款EGC-1B智能化心脑电图机、心电监护仪检定仪，检定的依据是JJG543-1996《心脑电图机》检定规程。使用该仪器不仅可以准确了解心电图机是否处于良好状态，还可用于对心电图机的故障检测维修。     

心电图机测量结果的不确定度评定

本文针对内蒙古计量院研发的ECG-1C型心脑电图机检定仪的特性,在心电图机检定中对电压信号和信号频率测量的不确定度评定进行了探讨,并得出了相应的相对扩展不确定度。     

心电图机的定标电压及走纸速度超差的调修

心电图机是用来描绘和记录心脏活动引发人体表面规定部位生物信号转化成电信号的一种医用电子诊断仪器。随着科学技术发展,心电图机已经广泛应用于临床,在心电图机的使用过程中经常遇到定标电压超差或走纸速度超差等问题,心电图机某一项指标超差,应当及时调修。不同指标的超差,调整方法是不同的,下面主要介绍定标电压超差及走纸速度超差的调修方法:一、lmV定标电压超差最常见一般由整机工作点不对或机内标准电压输出偏差造成。首先,用万用表测量机内标准电压输出,判断其是否正常。如不正常(1.35V电池电压不足),则需对此电压进行调整或更换…     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。