共查询到18条相似文献,搜索用时 78 毫秒
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建立起热脉冲法的新理论模型,分析了相应的测试技术问题。利用研制的微机测试系统 种材料的热扩散系数和导热系数进行了测定,得到了满意的结果,表明本文所提出的测试广阔进可信的。 相似文献
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基于热电比拟分析的理论,建立了地源热泵土壤热物性热电比拟的测试模型,并搭建了地源热泵土壤热物性测试实验台;对实验数据进行分析后,得出了西安地区土壤热物性参数的数据,验证了热电比拟模型测试土壤热物性参数的准确性。文中提出的热电比拟模型为土壤热物性测试提供了一个新的途径,对地源热泵的推广有积极的意义。 相似文献
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利用物质熔化与凝固过程中导热逆(或反)问题原理,在建立了相界面移动与两相热物理性质关系的基础上,提出了一种新颖的热物性动态测试方法,即由相变速率动态测试热物性参数。由于是对熔点高的金属进行测试,故不能采用解析求解,而是运用数值求解;并用铅、锌、铝等已知热物性的金属对此方法进行了评定,测试结果与参照值误差不超过3%;还对相变导热系数未知的铅锑、铅锡、铋锡、铝硅、铝铜5种共晶合金进行了测试,其结果具有较高的参考价值。该方法的优点在于测试过程中所求热物性参数与相界面位置是由精确的传热方程所约束,故测量较简便,结果准确、可靠、误差小,并可测得多个热物性数据。 相似文献
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K. Kobayasi 《International Journal of Thermophysics》1986,7(1):181-195
A method for the simultaneous measurement of thermal diffusivity and specific heat by a single rectangular heating pulse on a finite cylindrical specimen is described. The method takes into account radiation losses from all the surfaces of the specimen. The theoretical principle of the technique was studied by solving the transient heat conduction equation for a finite disk heated on the front surface by a single rectangular radiant energy pulse. An apparatus was constructed to comply with the theoretical conditions and was connected to a personal computer. Thermal diffusivity and specific heat were determined from the data obtained on the temperature response of the back surface of the specimen and from the theoretical results. This method can be applied to materials having a wide range of thermal conductivity values and has a good accuracy at high temperatures. Examples of the measurements are presented.Invited paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A. 相似文献
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L. P. Phylippov S. N. Nefedov S. N. Kravchoon 《International Journal of Thermophysics》1980,1(2):141-146
A method and an instrument for the measurement of a number of the thermophysical properties (thermal conductivity, thermal activity, volumetric specific heat, thermal diffusivity) are described. The results obtained for thermal conductivity and specific heat of toluene, over a temperature range 30–350°C and pressures of up to 30 MPa, are presented. 相似文献
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利用有限元方法对瞬态热线法导热系数测量进行了数值模拟,对各种因素如加热功率、热线半径以及实验温度等对测量过程的影响进行了分析,并将模拟得到的温升曲线与实验测量得到的温升曲线进行了比较,结果表明:通过选择适当的参数值,模拟曲线可以与实测曲线吻合得很好,实验值与模拟值的偏差小于实验结果的不确定度.本结果的获得对进一步理解瞬态热线法导热系数测量过程,提高导热系数测量技术水平具有借鉴意义. 相似文献
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B. L. Zhou 《International Journal of Thermophysics》1986,7(4):731-742
Various aspects of the importance of thermophysical property (TPP) studies to science and technology in China are discussed. Several stages of the development of experimental principles and equipment are described. Some examples of TPP applications in economic practice are presented. Theoretical and methodological studies in this field are summarized. The presentations are limited mostly to work on solids.Invited paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A. 相似文献
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采用苯胺化学氧化聚合制得盐酸掺杂态聚苯胺(PANI-HCl),考察了导电率以及介电常数随热处理温度的变化,并通过FT-IR、TGA、DSC和XRD等测试手段研究了空气气氛中不同热处理温度对PANI-HCl的掺杂程度以及微观结构的影响.结果表明:PANI-HCl在低于100℃的热处理保持优异的电导率和介电常数,电导率的数量级在100,介电损耗角正切tgδε≈0.35~0.49,当温度上升至160℃,电导率数量级下降到10-7,tgδε在0.1以下,其原因是由于热处理对掺杂态聚苯胺进行了脱掺杂,而且改变了聚苯胺的微观结构. 相似文献
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The errors in measuring the thermal diffusivity by the plane thermal wave method are considered as a function of the thermal
flux power density. The minimum values of the thermal flux power density required for measurements with a specified error
and the optimum parameters of the samples and of the heat source are determined.
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Translated from Izmeritel’naya Tekhnika, No. 8, pp. 44–46, August, 2007. 相似文献