红外体温检测手环的温度补偿研究

精准的腕部可穿戴测温设备,对于健康检测、疾病防控具有重大意义。外界环境因素对红外测温传感器的测量干扰较大,需要进行温度补偿。为此,设计一款基于MLX90614的红外体温检测手环,并对其温度补偿方法进行分析与研究。对环境温度、测量距离等因素进行实验,建立了腋下温度、腕部温度、环境温度之间的数学模型。最终证明该方法能够良好修正腕部温度的测量误差,在一定的环境温度范围内,最大温度偏差不超过0.1℃。     

背景影响下涡轮叶片温度测量及修正技术研究

在采用辐射温度计测量航空发动机涡轮叶片温度时,为了减小背景辐射对测温结果造成的影响,基于Planck定律建立包含背景辐射影响的测温方程,借助有效发射率计算得到被测目标的真实温度.通过设计背景辐射影响模拟试验,利用两个高温辐射源分别加热选定样品和模拟高温背景,采用扫描式涡轮叶片温度场测量装置对选定样品进行温度测量.结果发现,当目标设定为800℃、背景设定为1000℃时,目标在背景影响修正前后的最大温差为27.2℃,温差相对修正前温度的比例最大为3.82%,而修正后的目标温度明显更加接近无背景影响温度,从而验证了该修正计算方法的可行性和可靠性,对发动机研制过程中的温度监测工作具有重要应用价值.     

面向非稳态传热的热像仪相对测温性能评估

提出了一种热像仪相对测温的性能评价方法。将薄片热电偶的热节点固定在温度场均匀的加热单元表面,作为标准辐射温度发生单元,被待评价的热像仪观测和测温,对比热像仪观测的热电偶热节点表面温度场数据和热电偶自身测得的温度数据的相似度,对热像仪相对测温性能进行评价。基于国内外4个品牌的7款不同规格热像仪进行测试,结果表明热像仪的相对测温误差和绝对测温误差相差较大,相对测温误差通常介于噪声等效温差和绝对测温误差之间,同时发现6号热像仪性能较差,温漂严重,通过装置中的A、B两靶标同时测试热像仪性能,评价结果的标准差均在8%以内,这表明该方法具有较高的可靠性,对热像仪相对测温性能评价研究有一定的参考意义。     

热像仪示值校准和测温一致性测试实验研究

本文介绍了对凝视型红外热像仪的示值校准和测温一致性测试的实验研究。实验研究表明,在校准中,每次测量前进行热像仪自校正,可准确测量黑体辐射源的温度。使用稳定且温场均匀的腔式黑体辐射源和面辐射源进行热像仪测温一致性进行测试,得到较一致的结果。     

辐射测温坐标系的数学完备性分析

谱色测温法是一种无需发射率标定及空间几何标定的二维真实温度场的辐射测温法,适用对象为在测量窄波段内具有上述发射率表征的连续辐射的物体,由温度和发射率两个标尺构成的辐射测温坐标系是谱色测温法的重要特征之一.基于已有研究,对辐射测温坐标系的数学完备性进行讨论,在理论上验证了温度标尺、发射率标尺在测温坐标系中的单调连续性;并对二者进行了数值模拟,给出了一定测量条件下的辐射测温坐标系的理论分布,定量地分析了测量标尺的分布规律.这些理论与数值模拟工作可为测温坐标系在辐射测温中的应用提供必要的理论依据.     

测量距离对大型圆口径天线方向图影响的研究

本文运用互易原理导出了圆口径分布的天线近区辐射方向图与测量距离的关系。以圆口径指数型分布为例,计算了在不同测量距离下的辐射特性,从而研究了测量距离对天线方向图旁瓣特性的影响,给出了第一旁瓣测量误差与测量距离的关系曲线。最后,用5m环焦天线测量结果验证了理论分析和计算的正确性。     

影响红外测温的主要因素分析研究

红外测温在钢铁企业应用越来越广泛，成为钢企温度在线测量的关键设备。但在实际工作中，红外测温受到诸多因素影响，导致测温不准，影响产品质量控制。文章通过自主实验研究影响红外测温准确度最重要的发射率参数以及使用中安装距离等问题，综合确定几种钢材最佳发射率约为0.96(测温仪型号C316),使实验的几种钢种测量精度均能达到测量值的0.25%+1 K,并通过距离实验表明，即使在测试距离符合距离系数(D:S)的前提下，不同距离测量误差可能不同。本实验装置和方法可以为三钢不同的钢种或其它材料提供发射率测试，对测温仪发射率进行标定。     

焦炉炭化室侧壁连续测温系统的设计

文章阐述了辐射测温和比色测温的基本原理,在此基础上提出了一种适用于焦炉炭化室温度测量的光纤比色温度测量系统;利用双包层石英光纤解决工作环境温度高的难题,以STC12C5A60S2单片机为核心,采用MAX195AD转换器构成系统。该系统运用比色测温法克服外界干扰,提高了系统的温度精度和稳定性,达到了测温现场的指标要求,证明了理论研究的正确性。     

辐射测温仪表的原理和应用

辐射测温仪表是一种被广泛使用的非接触式测温仪器。本文概述辐射测温仪表的工作原理和结构特点,着重叙述辐射测温仪表的有效发射率设定、距离系数选择和环境条件对温度测量结果带来的影响,并介绍了辐射测温技术的应用和发展。     

地球红外辐射对大气层外红外测温的影响

针对环境辐射对弹道导弹防御(BMD)系统大气层外红外测温精度的影响问题,本文提出了分析地球红外辐射对红外测温精度的影响的方法.该方法根据双波段红外测温的原理,导出了考虑目标反射的地球红外辐射后,红外传感器对目标测量的色温计算公式,并给出了测量误差的分析方法.然后本文以BMD系统大气层外杀伤器(EKⅥ红外传感器为例,利用蒙特卡洛方法,分析了在假定的典型场景下,地球红外辐射对测温精度的影响程度.分析表明,地球红外辐射将使EKV红外测温的精度明显降低.     

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.     

Assessment of intakes of mixtures of radionuclides

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.     

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。     

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.     

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.     

Analysis of anisotropy of properties on the basis of studies of texture of coarse-grained ingots of thermoelectric materials

An analysis of anisotropy of the properties of a Bi₂Se_0.3Te_2.7 solid solution was carried out using construction of demonstrative surfaces for thermoelectric effectiveness and thermal expansion coefficients. It is shown that the texture is an important factor forming anisotropy of properties and technological fitness of ingots for manufacturing modules. Anisotropy of properties based on the studies of the ingot textures obtained using the float-zone method and Bridgman method (growing thermoelectric plates in a flat cavity) was studied.