低α精密电阻材料

本文介绍一种航天航空等高技术产品中精密电位器用的低电阻温度系数电阻合金，材料的电阻率和电阻温度系数是相互矛盾的物理量，要同时降低这两个参数是困难的，这正是本研究要解决的关键。本研究除根据有关资料设计了最佳合金成分外，着重研究了氧含量对合金电性能的影响，所研究的连续除气熔炼工艺使合金中氧含量降低到最低限度，从而使合金的电阻率保持在０．２６μΩ．ｍ时，电阻温度系数降低到１０×１０＾－６／℃以下。     

关于负温度系数热敏电阻R—T特性的探讨

本文介绍了几种求解负温度系数热敏电阻R-T关系的方法,并对各种方法的应用范围、特点等进行了分析.     

金属材料常温冲击吸收功的测量不确定度评定

为了掌握金属材料的冲击韧性,量化冲击吸收功指标,以便于更好的提供设计选材和研制新材料的技术依据,从而保证材料的使用安全性和合理性。根据GB/T229-2007《金属材料夏比摆锤冲击试验方法》及不确定度评定方法的要求,对金属试样常温冲击吸收功测量结果进行不确定度评定。     

Temperature Coefficient of Electrical Resistance of Simple Liquid Metals

The temperature coefficient of electrical resistance has for the first time been numerically determined for 15 simple liquid metals in view of the third-order term with respect to the pseudopotential of electron–ion interaction. The perturbation theory series for electrical resistance is constructed by the asymptotic expansion method. For all metals, the third-order term turns out to be positive and ranges from several percent to several tens of percent of the second-order term. Its inclusion improves considerably the agreement between the theoretical and experimental values of the temperature coefficient.     

Modeling of Thermal Processes in Thermal Resistors with a Positive Temperature Coefficient of Resistance

The space-time temperature distribution in materials with a positive temperature coefficient of resistance under the action of electric current on them has been analyzed by numerical methods. The nonstationary boundary-value heat-conduction problem with a nonlinearity of the third kind has been solved. The results obtained theoretically have been compared to experimental data. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 4, pp. 97–101, July–August, 2005.     

实验室标准传声器静压和温度修正系数的测量

为测量实验室标准传声器的静压和温度修正系数,在耦合腔互易法声压基准的基础上建立了静压调节系统和温度控制装置。对不同静压和温度条件下利用耦合腔互易法获得的传声器声压灵敏度进行线性拟合,得到不同频率条件下的静压修正系数和温度修正系数。实验结果表明低频段静压修正系数和温度修正系数基本保持不变,频率值在传声器膜片谐振频率值的1/2处,静压修正系数和温度修正系数分别存在最大值和最小值。     

Dynamic Measurements of the Temperature Coefficient of Resistance in the Transient Plane Source Sensor

The extended dynamic plane source (EDPS) method is one of the transient methods for measurements of the thermal conductivity and thermal diffusivity in solids. This technique uses a transient plane source (TPS) sensor, which serves as the heat source and thermometer. Its calibration consists of measuring the temperature dependence of the TPS sensor resistance and computing the temperature coefficient of resistance (TCR) using least-squares (LS) estimation. The goal of this study is to calibrate the TPS sensor directly in the apparatus for the EDPS method. The article presents an uncertainty assessment of the TCR measurement. The main sources of uncertainty stem from resistance measurements of the constant resistor and platinum thermometer calibration. The LS estimate of the TCR in a nickel TPS sensor is 4.83 × 10⁻³ K⁻¹ at 20 °C and 4.57 × 10⁻³ K⁻¹ at 45 °C with a combined standard uncertainty better than 0.04 × 10⁻³ K⁻¹, which is 0.7 %.     

Measurement of the Thermal Diffusivity of Metallic Foils and Films by the Photoacoustic Method1

The thermal diffusivities of four kinds of metallic foils from 20 to 200m in thickness were measured by a photoacoustic method on the basis of the Rosencwaig and Gersho theory. The measured data for continuous foils of uniform microscopic structure almost agreed with the literature values. Measurements were also carried out on two kinds of metallic thin films with of 10m thickness produced by sputtering. The difference in thermal diffusivity between the foils and the sputtered films depended on the uniformity of the microscopic structure.     

铌掺杂氧化锡陶瓷的电阻负温度系数特性

利用共沉淀方法合成了Nb掺杂SnO2材料,通过X射线衍射分析了材料的相组成,利用电阻-温度特性测试仪研究了材料的电阻温度特性,并利用半导体热力学理论分析了材料的NTC机理.结果表明,600℃煅烧能获得高纯的四方结晶相掺杂SnO2,粉体晶粒平均尺寸为10.5nm;Nb掺杂SnO2体现出良好的电阻负温度系数(NTC)效应,材料常数为3662K.     

Research on the Temperature and Emissivity Measurement of the Metallic Thermal Protection Blanket

The temperatures and emissivities of the metallic thermal protection blanket at (900–1,300) °C are investigated experimentally by using a multi-wavelength pyrometer. A linear relation between the emissivity and true temperature at different wavelengths is assumed. Based on this assumption, the true temperatures and spectral emissivities of the metallic thermal protection blanket at the two temperature measurement points can be calculated simultaneously. Some experimental results for the practical data processing of measurements performed on the metallic thermal protection blanket show that the difference between the calculated temperature and the temperature measured by a standard thermocouple is within  ±  10°C.     

分形基片上无序金属薄膜的阻-温特性

研究了沉积在具有无规分形结构的α－Al2O3陶瓷基底上的两侧非平整无序Pt和Au薄膜的异常R－T特性。实验结果表明：在12～200K的温区内，当薄膜的方块电阻减小至102～103Ω量级时，基底上的分形结构开始对样品的R－T特性产生明显的影响，电阻温度系数由正向负急剧转化。分析认为，在低温区的此种异常现象是由薄膜中的电子－电子相互作用和电子的弱局域化效应引起的。     

全金属孔板叠层换热器流动阻力的测试

全金属孔板叠层换热器是由铜制孔板和不锈钢隔片相间叠置，采用扩散焊工艺焊接而成。该换热器横断面为长方形，采用指型流道。作者对三个样品进行了室温下的流动阻力测试，得出了摩擦因子随雷诺数变化的关系曲线，并用最小二乘法整理成摩擦因子计算公式。     

Multimode Sapphire Resonator for the Measurement of Surface Resistance of HTS Films

A multimode sapphire resonator is developed for multiple frequency surface resistance measurement of a single piece of high-temperature superconductor thin film. Simple formulas are used for the calculations of surface resistances. On this sapphire resonator, three modes, TE_011+ε , TE_012+δ and TE_021+ξ (0<ε,δ,ξ<1), which had resonances at 11.84, 17.49 and 31.99 GHz were used simultaneously and the measured surface resistances at these frequencies were 0.553, 1.32 and 3.75 mΩ, respectively. The measured result matches the theory very well.     

连续金属薄膜的电阻率研究

运用玻耳兹曼方程研究金属薄膜中的电子输运 ,考虑了来自表面和晶粒间界的散射 ,计算连续金属薄膜的平行电阻率。得到的电阻率理论曲线与实验曲线符合得很好。弥补了F S理论在较薄厚度时电阻率理论结果与实验结果不相符的缺陷。     

Electrical Resistance Measurement of Glass Transition and Crystallization Characteristics of Zr—Al—Cu—Ni Metallic Glasses

In this paper,glass transition and thermal stability of the Zr-Al-Cu-Ni metallic glasses were investigated by using electrical resistance measurement(ERM),DSC and X-ray diffraction techniques.The experimental results show that the ERM is capable of detecting the glass transition of the amorphous alloys and can help to distinguish the crystallization products of the Zr-Al-Cu-Ni metallic glasses owing to the difference of the electrical resistivity between the precipitation phases.     

低温电阻应变式传感器测量技术的研究

电阻应变片是广泛应用的传感元件之一,已成为电测技术中重要的检测手段。将其制成电阻应变式传感器可以用来测量多种参数。但是,常用的电阻应变式传感器主要是在室温环境条件下使用,对于在低温环境条件下使用的电阻应变式传感器的研究很少。本文旨在针对低温,主要是在液氮(-196℃)温区下开展电阻应变式传感器测量技术的研究,通过将试验结果同理论计算结果相比较来分析该电阻应变式传感器在液氮温区下的测量性能。结果表明,在应变片正确粘贴及良好固化的情况下,低温电阻应变式传感器能够在液氮温区给出较高精度的测量结果。     

工业用铂热电阻温度电阻值测量结果的不确定度评定

本文详细介绍了A级铂热电阻温度电阻值测量结果的不确定度评定方法.     

基于热电模块实验的低温下塞贝克系数的测量

利用热电发电器（TEG）进行温差发电是LNG冷能利用的方式之一,而目前低温下热电材料塞贝克系数（α）研究的缺失给低温TEG的设计带来了障碍。因此,本文提出一种通过TEG模块的实验得到低温下该模块所用热电材料α的测量方法,并测试了热电材料Bi2Te3在90~180 K温度范围内的α。结果表明：Bi2Te3在低温下的α随温度的降低而减小,温度从180 K降至90 K,塞贝克系数从124.6 μV/K降至49.3 μV/K,且与温度成二次函数关系。     

Influence of Resistance Method on Motor Winding Temperature Rise Measurement

The objective of this article is presentation of influences when measuring the motor winding temperature rise in the scope of safety testing of electrical appliances, with respect to conformity assessment. The temperature measurement in testing is one of the most defined fields of measurement, but it is very important how the measurement is performed. Standards only describe that the resistance method shall be used for determination of the temperature rise (heating) of the winding. The temperature rise is defined as the average temperature rise of the windings above the ambient (surrounding) temperature, at the specified load of the unit under test. It is not explicitly defined how to approach this measurement when using cooling characteristics of the winding for determination of the temperature rise. Since the extrapolation curve is used, the procedure is also very important to obtain a result as accurate as possible. It is important that measurement results and their associated uncertainties are correctly evaluated, and on that basis, appropriate conclusions of conformity of the product with specifications are made. The resistance method influence on the motor winding temperature rise measurement is a case study in this article. The article focuses on the measurement of the temperature rise of electrical motors used in electrical appliances according to the standard EN 60335-1, clause 11 (2002) (identical as standard IEC 60335-1, 2001). In this article, the influencing parameters are analyzed when measuring the temperature rise of electromotor winding. As a case study, concrete measurements are presented. The optimal time after which the performer has to start measurement of the cooling characteristics is analyzed, since the motors are typically mounted deep into appliances. Especially for a collector motor winding, it takes some time for a performer to be able to connect the measuring instrument to collector??s lamellas because this contact has an important influence on extrapolation results.