闪光光源有效光强标准测量装置研究与建立

建立了可溯源到国家照度工作标准的有效光强标准装置,该装置由闪光光源、中性滤光片、光度探测器、波形采集和处理单元组成,可定标相关测量仪器。分析了氙灯闪光灯和测试LED闪光灯,LED闪光灯具有上升沿陡峭、稳定性好等优点,可进一步优化作为有效光强标准灯。对影响实验的因素进行了分析,结果表明整套装置测量有效光强的不确定度水平达到2.4%(k=2)。     

LED光源双应力交叉加速寿命试验

在LED光源的特性和寿命试验原理的基础上,基于单一应力的加速寿命测试方法,结合温度应力与电应力,提出LED光源双应力交叉加速寿命试验的方法,并详细阐述了加速寿命试验与测量系统架设,建立寿命试验的数学模型,根据参数测量与分步计算进行寿命评估与可靠性分析。该方法可大大缩短试验周期,具有较高的实用性,为LED光源的寿命评估和可靠性分析提供一种高效实用的方法。     

一种基于PXI总线的便携式电学多参数校准装置研究

根据公司专用测试设备的量值溯源要求,本文研制了一种基于PXI总线的便携式电学多参数校准装置,解决了专测设备在现场的电压、电流、电阻和时间等参数的溯源问题,并具有良好的可扩展性。     

普通照明用非定向自镇流LED灯光通维持率校准方法的探讨

正一、实验装置1.实验方法及配套设备本次实验采用的实验装置:积分球法,测量光源的初始光通量、电功率、光通维持率等参数。测试时,屏蔽周围环境光,使用的电源及监测仪表应符合GB24824-2009《普通照明用LED模块测试方法》中的要求。光通维持率测试结果应满足GB/T24908-2014《普通照明用非定向自镇流LED灯性能要求》中的要求。     

介质谐振器介电参数频响特性及频率温度系数的测量

本文讨论了微波介质谐振器介电参数频响特性和频率温度系数的测试方法、测试装置和测试系统。用Q值较高的TE0mn模作为测试介电参数的工作模式 ,取不同下标m和n的TE0mn模式进行测量 ,以获得介电参数的频响特性。为克服常规测试方法因耦合方式不当激励起杂模干扰高次TE0mn 模测试的问题 ,提出了新的耦合方式 ,研制了测试装置。同时 ,还研制了结构巧妙的频率温度系数测试装置。实测表明 ,该测试方法、测试装置和测试系统能对介电参数频响特性及频率温度系数进行快速、准确、可靠、无损伤和批量的自动测试。     

多参量电测设备自动校准装置的研究

多参量电测设备是各计量测试部门和企业普遍使用的一类设备,为保证其量值有效溯源,我们研制了多参量电测设备自动校准装置.该装置通过采用发热区和恒温区隔离技术,并设计无源的、高准确度的小型V/V变换器和I/V变换器,解决了国内现有校准设备普遍存在的量程范围窄、小电压（流）和大电压（流）信号输出稳定性差的问题;通过设计切换控制模块实现了多参量电测设备的输出/测量功能在一个装置上完成校准的问题;通过开发自动校准软件实时采集数据并自动进行分析处理、误差计算,记录打印等,实现了多参量电测设备的自动校准.     

一种闪光动态参数校准方法

建立了闪光测量理论模型,提出了一种利用亮度阶跃信号校准闪光动态参数的方法,分析了闪光持续时间、动态亮度和闪光强度测量误差的来源,阐述了通过静态亮度和时间参数实现闪光动态参数量值溯源的方法。利用LED光源发出的亮度阶跃信号测定了闪光测量系统的阶跃响应,分别计算了闪光参数的各误差分量,推导了测量不确定度计算公式,测量了氙灯闪光参数并给出了测量不确定度。结果表明该方法可实现闪光动态参数的计量校准和量值溯源。     

激光辐射探测器特性测试研究

本文介绍一种以稳定的He-Ne激光器、CW-YAG激光器和CO_2激光器为测试光源的激光探测器特性测试装置,用来评价激光探测器的参数质量。     

手指静脉识别系统矩形阵列光源特性分析及优化设计

手指静脉图像质量的高低直接影响手指静脉的识别效率。针对单个近红外LED的光照均匀度相对较差,如何利用多个近红外LED构造一个高质量的光源进行了研究。讨论了矩形阵列光源的结构、空间、形状等参数对静脉图像影响,利用斯派罗法则对各种参数极值找出最优解,再结合手指个体的差异和指型特性,设计照度面为25mm×25mm矩形光源阵列。通过对比实验,利用最优参数设计的阵列光源,能够采集到高质量的手指静脉图像,为手指静脉采集设备光源设计提供参考,同时为后续的手指静脉图像的识别打下基础。     

新一代光源LED的特性及检测方法

LED被誉为是白炽灯、荧光灯后新一代光源。因其众多优点,如今在普通照明领域取代传统光源的步伐已经越来越快。LED的发光机理和传统光源有着很大的差异,也就使得它们的光、电、热等特性有着很大的不同,相应的检测方法也就有所不同。下面的文章将对此作一介绍。     

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)。