婴儿辐射保暖台氧监测器的校准

近年来越来越多的婴儿辐射保暖台特别是进口婴儿辐射保暖台配备了氧气混合装置,其氧浓度是需要计量溯源的,本文填补了这一项空白,讨论了婴儿辐射保暖台氧监测器的校准方法及校准不确定度,为医疗计量的发展做出了贡献。     

婴儿辐射保暖台温度参数校准方法

婴儿辐射保暖台是医院必不可少的医疗设备,本文着重介绍婴儿辐射保暖台的温度参量的校准方法,该方法科学、简便,已经发布为地方校准规范,可作为计量部门校准、医院质量控制的技术依据.     

基于黑板温度计的婴儿辐射保暖台温度偏差校准方法

该文主要研究设计婴儿辐射保暖台的温度偏差校准方法。由于婴儿辐射保暖台使用的是非封闭式的红外辐射加热方式,因此不能使用传统的测温方式对其温度进行测量,该文作者通过多项试验数据的比较对婴儿辐射保暖台温度参数的校准进行多种试验方法的筛选,最后选择黑板温度计作为校准温度参数的标准器,根据试验需要设计出适用于试验的黑板温度计,提出一套系统的婴儿辐射保暖台的温度偏差校准方法,并且按照提出的校准方法完成数据分析及校准不确定度的讨论。试验数据分析证明所提出的辐射保暖台温度校准方法的可行性,因此该文提出的以使用黑板温度计作为标准器为基础的温度偏差校准方法是适用于实际工作的。     

婴儿辐射保暖台温度校准实验研究

针对婴儿辐射保暖台的温度校准,通过多项试验数据的比较进行了多种试验方法的筛选,最后设计出了黑板温度计,提出了一套婴儿辐射保暖台的温度检测系统方法,并且按照提出的校准方法完成了实验和数据分析。试验结论证明了所提出的辐射保暖台温度校准方法的正确性和必要性。     

婴儿辐射保暖台红外辐照度的测量

近年来婴儿辐射保暖台的测量需求越来越多,其中红外辐照度的指标会影响婴儿的生命安全,但目前还没有相关的研究,本文填补了这一项空白,讨论了婴儿辐射保暖台红外辐照度的测量方法,并提出了相应的参考指标,为医疗计量的发展做出了贡献。     

现场温湿度校准系统

介绍一套温湿度校准系统,用于多台环境试验设备温度、湿度参数的校准,其系统是由高精度的铂电阻温度传感器、湿度传感器、数据采集单元和校准软件组成,实践证明,该校准系统已经成功应用于环境试验设备的温度和湿度进行自动校准,提高了计量校准的工作效率.     

温度变送器(带传感器)现场检测影响因素探讨

文章针对温度变送器(带传感器)现场校准的影响因素,从恒温设备的温场、校准环境条件和感温端插入温场深度等方面进行实验室校准和现场校准试验,通过试验获取数据并进行分析,提出了温度变送器(带传感器)现场校准合适的环境条件、感温端插入温场深度的要求和恒温设备温场介质选择,为温度变送器(带传感器)现场校准提供了依据和参考,有利于提高温度变送器(带传感器)现场校准的准确度和可靠性。     

干式计量炉对不同类型测温传感器校准误差影响的探讨

目前干式计量炉校准测温传感器已经在工业上大量普遍使用,但相关的测量系统仍缺乏整体校准方案,存在不同装置获得的测量结果一致性较差等问题.本文通过校准不同类型测温传感器的实验,探讨了不同装置对校准测温传感器的误差影响大小.经过实验验证,干式计量炉可校准尺寸和孔径匹配的中低温热电偶传感器,且采用辅助措施减少测量误差,也可校准部分热电阻传感器.     

多通道压力传感器校准系统研制

介绍了一种多通道压力传感器校准系统,该系统通过通过自动控制和采集技术实现了多通道压力传感器校准系统研制,提高了压力传感器计量校准工作效率及工作质量。     

招远 开展计量器具检测校准

计量器具的准确与否直接关系百姓利益,近日,山东省招远市局计量工作人员深入全市各大超市及摊位开展计量器具现场检测校准。计量工作人员深入全市20个超市进行现场检测校准．检测60余台电子秤．现场对3台有轻微计量失准的电子秤进行了校准,确保其计量准确。     

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.     

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.     

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.     

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 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.     

Numerical study of methods of linearization of the output characteristics of radio-frequency sensors of the level of dielectric media

Different constructions of the sensing elements of radio-frequency level sensors based on sections of long lines are numerically investigated by means of the Matlab program for the purpose of minimizing the measurement error caused by the nonlinearity of the output characteristic. It is shown that the nonlinearity is lowest for U-shaped designs. The nonlinearity factor KN may be regulated by varying the capacitance of a correcting capacitor connected to the input of the sensing element and (or) the length of one of the sections of the long line. In selecting an optimal capacitance of the correcting capacitor KN ≤ 0.15% for control media with dielectric permittivity in the range 2.2–30.     

Possibilities of Decreasing the Errors of Determination of the Height of the Pole of a Sessile Drop of Melt

We analyze the possibilities of decreasing the errors of measuring the height of the pole of a sessile drop of melt above its equator by determining the position of the equator according to the midpoints of vertical chords of the image of the drop. The optimal distance between these chords and the edge of the image of the drop is chosen within 10–20% of the radius of the equator. The proposed method guarantees the same level of errors of evaluation of the height of the pole and the radius of the equator, which enables one to substantially increase the accuracy of evaluation of the capillary constant and the surface energy of the melt according to the geometric parameters of the sessile drop.     

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.