A New Pulse Hot Strip Sensor for Measuring Thermal Conductivity and Thermal Diffusivity of Solids

The pulse hot strip method is a newly developed dynamic method to measure the thermal conductivity and thermal diffusivity of solids. It is based on monitoring the temperature response of a sample to a very short heat pulse liberated by a strip heat source. The instrument's uncertainty is estimated to be less than 3% for both quantities.     

碳／碳复合材料高温多热物性参数测量系统

提出一种将多光谱辐射测温技术、激光狭缝扫描检测技术和对试样通电加热至稳态技术相结合的新方法,可对碳/碳复合材料在高温下的多个热物性参数进行测试.利用大电流快速将棒状碳/碳复合材料加热至稳态.通过辐射高温计对试样表面温度分布的测量和激光狭缝扫描检测仪对膨胀量的测量,根据流过试样的电流、电压就可计算出被测试样的电阻率、热膨胀系数、导热系数、比热、全波长半球向全发射率和多个光谱下的法向光谱发射率.该装置主要包括高温环境实验箱,加热供电回路、高速光学高温计、激光狭缝扫描检测仪等部件,介绍了各组成部分及其工作原理.激光狭缝扫描检测仪的最大测量误差小于±3um,两套温度计的测量精度都优于1%.     

点热源热脉冲法测算生物流体的热物性参数

采用微珠状热敏电阻作为点热源和测温元件，在一维点源脉冲传热模型的基础上建立一种同时测量生物流体热扩散系数、导热系数和热容的瞬态方法。运用非线性参数拟合，直接从感温热敏电阻对热脉冲温度响应中同时获取待测的热物性参数。实验中设计了一个高灵敏度的温度测量电路，测试结果表明，本方法测量误差小于4％。此外，还讨论了测量数据的处理和影响测量的因素。     

Variational Methods for Experimental Investigation of Thermophysical Properties and Thermal Analysis of Various Objects

The methods of automated determination of the thermophysical properties and thermal analysis of various objects (solid bodies,dispersed materials, and liquids) are substantiated. They are based on program variation of thermal fields in the experiment.     

“Thermal Mirror” Method for Measuring Physical Properties of Multilayered Coatings

In this study theoretical principles underlying the photothermal displacement (“thermal mirror”) method for measuring physical properties of opaque multilayered and functionally graded coatings with low thermal conductivity are analyzed. In this method, the specimen is locally heated by a power laser beam, and a two-dimensional transient temperature field is formed in a specimen. The physical basis for the photothermal displacement method is the non-stationary buckling and displacement of an irradiated surface due to a non-uniform thermal expansion. The surface is monitored by a low-power probe beam of a second laser, which is reflected from the specimen, i.e., the system operates as a convex “thermal mirror.” The photoinduced displacement varies with time, and the probe beam is reflected at a different angle depending on the slope of the displacement. The deflection angle is measured as a function of time by a position sensor, and the results of these measurements are compared with the theoretical dependence of the deflection angle on time and physical properties of a coating. This dependence was determined analytically from the solution of the two-dimensional thermal elasticity problem. It is shown that for the specimen composed of a substrate and a coating it is feasible to determine the properties of the coating, e.g., the thermal diffusivity and coefficient of linear thermal expansion provided that the analogous properties of the substrate are previously measured or otherwise known.     

铝合金隔热型材隔热性能检测方法及测量不确定度评定

传热系数测试是评价铝合金隔热型材隔热性能指标的重要途径,建立了铝合金隔热型材检测方法,分析了影响铝合金隔热型材传热系数测量的不确定度来源,对隔热型材传热系数测量不确定度进行评定分析,结果表明在（2．90—0．06）至（2．90＋0．06）W·m-2·K-1的区间包含了传热系数K测量结果可能值的95％,并提出了测量传热系数的注意事项。     

用于非接触测量的光学传感器

本文介绍了一种用于批量零件进行公差带测量的传感器．由一个双光束投射系统将具有互补色的光带投射到被测零件表面，通过显微系统接收后，由视场中光带的颜色即可判定该被测零件是否合格，并可判定被测件尺寸的超差方向。由于该传感器采用的是光学非接触测量法，所以适用于橡胶、塑料以及软金属的测量．     

A Method of Measuring the Angular Coordinates for Objects Moving in a Group

A method is proposed for measuring the angular coordinates of objects moving in a group. It is based on the statistical characteristics of the complex reflection coefficients of a group and the errors of measuring the velocities of the members. Inverse antenna aperture synthesis is used to increase the angular resolution.Translated from Izmeritel’naya Tekhnika, No. 3, pp. 12–18, March, 2005.     

A Nanowatt Smart Temperature Sensor for Dynamic Thermal Management

The amazing integration densities achieved by current submicron technologies pay the price of increasing static power dissipation with the corresponding rise in heat density. Dynamic Thermal Management (DTM) techniques provide thermal-efficient solutions to balance or equally distribute possible on-chip hot spots. Accurate sensing of on-chip temperature is required by optimally allocating smart temperature sensors in the silicon. In this paper, we introduce an ultra low-power (1.05–65.5 nW at 5 samples/s) tiny (10250 $mu {rm m}^{2}$) CMOS smart temperature sensor based on the thermal dependency of the leakage current. The proposed sensor outperforms all previous works, as far as area and power consumption are concerned (more than 85% reduction in both cases), while still meeting the accuracy constraints imposed by target application domains. Furthermore, a specific interface based on the use of a logarithmic counter has been implemented to digitalize the temperature sensing. These facts, in conjunction with the full compatibility of the sensor with standard CMOS processes, allow the easy integration of many of these tiny sensors in any VLSI layout, making them specially suitable for modern DTM implementations.      

A Monolithic CMOS Autocompensated Sensor Transducer for Capacitive Measuring Systems

In this paper, a monolithic complimentary metal-oxide-semiconductor (CMOS) autocompensated sensor transducer for capacitive measuring systems is newly presented. The proposed converter is compact and robust to integrate in capacitive measuring systems. The proposed autocompensated sensor transducer is attractive due to the fact that a digitized signal is produced without realizing the analog-to-digital converter. Hence, the hardware cost could be reduced. Furthermore, the output signal of the proposed transducer is a pulse stream; it could be easily sent over a wide range of transmission media, such as package switch networks (PSNs), radios, and optical, infrared (IR), and ultrasonic media. Another innovation is that the proposed automatic compensation circuits enhance and compensate the linear relation between the variable capacitance of the detected sensor and the output digital frequency over a wide dynamic frequency range. Measurement results have successfully verified the functions and the performance of the proposed autocompensated sensor transducer and confirmed that it is possible to apply it to the air pressure sensor. The area of this chip is 940 times 1080 mum², and the power consumption is 6.4 mW. The proposed transducer is not only suitable for capacitive measuring systems but also practical for application in the front-end systems of the wireless sensor network.     

A Novel Comparative Photothermal Method for Measuring Thermal Diffusivity

A novel comparative method has been developed at the National Physical Laboratory (NPL) to measure the thermal diffusivity of semi-infinite samples without a priori knowledge of the boundary conditions. It is based on photothermal radiometry, and involves the detection of modulated thermal radiance from a target irradiated by a modulated, focused diode laser beam with a power of 1W. The technique exploits the fact that the frequency response of the surface temperature modulation scales with thermal diffusivity for a given target geometry (this is a fundamental property of the heat diffusion equation). In the process two samples are measured, one of which is known, and the diffusivity of the second material is derived from scaling the results over frequency. Measurements on samples of platinum and Inconel have shown the validity of the methodology but also raised issues concerning the difficulty of accurate measurements due to surface coatings or roughness.Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22--27, 2003, Boulder, Colorado, U.S.A.     

用于机器人关节的柔性压力触觉传感器设计

分析了碳纤维/硅橡胶导电复合材料的拉伸、弯曲及压敏特性,基于上述特性设计了一种新型的应用于机器人关节等活动部位的柔性压力触觉传感器。通过解耦算法解决了拉伸、弯曲引起的干扰问题,构建了求解接触压力的数学模型。实验结果表明,该柔性触觉传感器具有拉伸和弯曲性,并消除了拉伸和弯曲对接触压力的检测的干扰,可应用于机器人关节。     

A Calorimeter for Measuring the Total Thermal Resistance of Textile Materials

The operating principle and construction of a calorimeter to determine the total thermal resistance of textile materials are considered. The choice and calculations of the main parameters of the individual units of the calorimeter are validated. Formulas for processing the results of measurements are presented.     

Hot-Ball Method for Measuring Thermal Conductivity

This article deals with the theory and performance of a sensor for measuring thermal conductivity. The sensor, in the form of a small ball, generates heat and simultaneously measures its temperature response. An ideal model of the hollow sphere in an infinite medium furnishes a working equation of the hot-ball method. A constant heat flux through the surface of the ball generates the temperature field. The thermal conductivity of the surrounding medium is to be determined by the stabilized value of the temperature response, i.e., when the steady-state regime is attained. Error components of the sensor are discussed due to analysis of the deviations of the real hot-ball construction from the ideal model. The functionality of a set of hot balls has been tested, and the calibration for a limited range of thermal conductivities was performed. A working range of thermal conductivities of tested materials has been estimated to be from 0.06 W· m⁻¹ · K⁻¹ up to 1 W· m⁻¹ · K⁻¹.     

A Transient Heating Technique for Measuring the Thermal Diffusivity of Metals

A transient heating technique, improving the constant-rate-heating technique for the measurements of thermal diffusivities of metals, is proposed. For a physical model of a specimen to be measured, the transient heat-conduction equation was solved with some boundary conditions, and the solution obtained was used as the principle of the present transient heating technique for determining the thermal diffusivity of the specimen. Additionally, a thermal analysis was made to satisfy a boundary condition involved in the principle, that is, the condition of radiative thermal insulation at the two end surfaces of the specimen. To verify the validity of the present technique, the thermal diffusivity of iron, whose thermophysical properties are well-known, was measured with the same apparatus as used in our previous work, and the experimental results are discussed. Moreover, thermal diffusivities of thermocouple materials, namely, constantan, chromel, and alumel, were measured by the technique in the temperature range of 360 to 680 K.     

Determination of the Effect of Variability of the Thermal Properties of Materials When Measuring Thermal Conductivity Using Steady-State Thermal Methods

The corrections for distortion of the temperature field are determined by solving a nonlinear differential equation under conditions when the thermal properties of the material are variable, and the thermal conductivity is calculated for calorimeters operating under steady-state thermal conditions. The condition under which these corrections are zero is obtained.     

一种机器人光电式滑觉传感器的研究

为实现机械手对易碎物品的无损伤抓取,要求机械手具有滑觉检测功能,本文设计了一种光电式滑觉传感器,它由红外光电器件和一个具有反射镜面的弹性体组成,当物体有相对滑 时会引起反射镜面的振动,由此引起光电传感器的输出信号发生变化,对传感器信号进行一定的数学处理,就可以判别物体的相对滑动。本文通过实验分析,建立了滑动程序判别模型,利用这个模型在电伺服机械手上实现了对鸡蛋等易碎物吕的无损伤抓取     

A Radar System for Measuring the Wave-Forming Properties of Ships

A measuring system which uses a shore-based radar station and standard computers is considered. It is shown that, using semiexperimental computer modeling, the accuracy of the radar measuring system is quite acceptable for estimating the wave-forming properties of ships.Translated from Izmeritel’naya Tekhnika, No. 3, pp. 46–48, March, 2005.     

R410A热力性质的拟合计算

采用拟合关联式简便计算方法,对制冷剂R22主要替代工质之一的R410A的热力性质在饱和温度-40～60℃,过热度0～60℃范围内进行了拟合,并分析了误差。结果表明：采用该方法得到的拟合模型与参考数据源相比,在保证物性计算速度和稳定性的前提下,精度满足工程计算所需的要求,适用于系统的仿真和优化计算以及过程的实时控制。