试验桌对辐射骚扰测量的影响

通过实验研究试验桌对辐射骚扰试验的影响,寻找测试数据差异产生的原因及解决方法。实验结果表明,辐射骚扰测试时应使用介电常数低的测试桌以减小不确定度。该研究对于电磁兼容测试中的辐射骚扰测量具有一定的参考价值和指导意义。     

电磁辐射骚扰测量的不确定度评定

电磁辐射骚扰测试是电磁兼容中的重要项目,在给出测试结果的同时要求给出测量不确定度。本文分析了1～6GHz电磁辐射骚扰项目的不确定来源,重点对试验桌引入的不确定度要素进行详细评定,最后进行了合成标准不确定度的计算,为电磁兼容实验室的不确定度报告的评定提供了参考。     

基于3米法半电波暗室中30MHz到1GHz的辐射骚扰检测的测量不确定度评定

根据GB/T 6113.402-2006的要求,系统地考虑了频率范围为30MHz到1GHz的辐射骚扰检测过程中的不确定度来源,分析影响测量结果的不确定度各个因素,建立测量结果不确定度评定的测量模型,并计算评定了频率范围为30MHz到1GHz的辐射骚扰检测测量结果的不确定度。     

电磁兼容辐射骚扰场强测试能力验证的探讨

为减小不同实验室辐射骚扰场强测试结果的差异,保证测试结果的量值统一,研究电磁兼容辐射骚扰场强测试能力验证。从测试方法、测试场地、测试系统、测试人员等方面系统分析测试结果的主要影响因素,提出具体的实施方法,提高测试结果的可靠性。实践证明:该方法有助于主导实验室和参比实验室对电磁兼容辐射骚扰场强测试能力验证活动的顺利实施和执行;同时,可提升电磁兼容检测实验室的检测能力。     

利用吉赫兹横电磁波室实现电能表辐射骚扰测量

一个能进行30~1000MHz频率范围电能表辐射骚扰测量装置已在中国测试技术研究院电子所初步建成。该装置成功利用吉赫兹横电磁波小室(GTEM小室)作为测量场地与骚扰能量接收装置,其特点是占地少、造价低、使用方便,特别适用于各种单、三相电子式电能表及其他便携式仪表的测量。如采用较高频段的信号源和接收机(或频谱分析仪),该装置的频率范围可方便地扩展到2GHz甚至3GHz,能满足当前及今后相当长时期内国家标准及IEC标准对骚扰频率范围的测量要求。其测量不确定度主要受限于所使用的干扰接收机或频谱分析仪,在低频段(100MHz以下)还受限于GTEM小室接收系数AF的测量与校准。     

机载龙伯透镜天线用聚苯乙烯泡沫塑料的制备及介电常数调控

针对雷达通讯微波频段新型轻质介电复合材料的迫切需求,开展高介电性能复合材料的研究具有现实意义。采用悬浮聚合法制备不同密度的聚苯乙烯泡沫,研究了聚苯乙烯泡沫的介电常数与密度之间的关系,分析了钛酸钡粉末的介电性能。采用干混法添加钛酸钡粉末制备介电常数可调控的轻质钛酸钡/聚苯乙烯复合泡沫。聚苯乙烯泡沫的介电常数随密度增大,表现出弱的频率依赖性和低介电损耗。钛酸钡粉末具有高的介电常数和较低的介电损耗。BaTiO_3/PS复合材料的介电常数随着BaTiO_3含量的增加而升高。相同介电常数的BaTiO_3/PS复合材料和聚苯乙烯泡沫相比,密度显著下降,说明添加BaTiO_3可以实现介电材料的轻质化。     

预电磁兼容实验室辐射骚扰测试的误差分析与改进方法

为了减小预电磁兼容实验室和标准试验室在辐射骚扰测试时的误差,本文通过对预兼容实验室和标准试验室结构和在其进行的辐射骚扰测试过程进行分析,找到了引起测量误差的几个重要因素,提出了减少测量误差的可行方法并通过引入实验室校准因子对测试结果进行修正,通过大量的测试验证了方法的可行性。     

30MHz～1GHz辐射骚扰测量不确定度评定

正一、简述30MHz~1GHz辐射骚扰测量是在5m法半电波暗室内,使用ESU26测量接收机通过电缆连接到Schwarzbeck VULB9163宽频对数周期天线进行测量,将天线系数及电缆的衰减叠加到测试接收机的读数上来获得实际的辐射骚扰值。1.测量方法被测设备工作时产生的辐射骚扰信号在半电波     

标准ANSIC63.4-2014新要求

介绍美国电磁兼容标准ANSI C63.4-2014的新要求,包括天线、测试场地、1 GHz以上辐射骚扰测量及其他特殊要求,并对复合型天线的验证及场地归一化衰减的最新方法进行重点阐述。     

带状线法测试辐射骚扰的方法浅析

针对常规天线法辐射骚扰测量中，接收天线的位置和被测件不同极化方向影响测试结果的问题，采用带状线法进行辐射骚扰测试的方法，使辐射骚扰的测试过程更为简单便捷。     

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.     

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.     

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.     

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)。