Measurements of the Thermal Conductivity and Electrical Conductivity of Carbon Nanofibers

（1）在不同的制造条件下测量了单个碳纤维的热导率。阐明了热处理温度对导热系数的影响。测试结果表明，随着热处理温度的升高，导热系数显著增大，在700 ~ 3000℃温度范围内，导热系数增大了几百倍。阐明了热处理温度对单根碳纤维横截面微观结构的影响。（2）测量了不同填充密度下碳纤维的导热系数和热扩散系数。填充碳纤维的导热系数很大程度上取决于填充密度。阐明了导热系数与填充密度之间的关系，并进一步测定了填充碳纤维的电导率。 ...更多信息 准确地说（3）利用微电子机械系统（MEMS）技术，对碳纤维探针进行了微型化处理，使之适用于纳米尺度样品的测量。成功制备了宽100 nm、厚40 nm、热线部分长6 μm的纳米薄膜探针。已经证实，这种纳米探针可以用于测量直径为几十纳米的碳纳米管的热导率。(4)By在国立先进工业科学技术研究所的操作SEM内使用局部聚焦电子束照射，碳纳米管的一端已经成功地附着到纳米探针的中心部分，以制造T型纳米传感器。（5）在测量单个碳纳米管的热导率之前，必须知道铂纳米膜的热导率和电导率，并且这些值已经被精确测量。发现纳米膜的两个当前测量值小于本体值的一半。（6）在100-320 K温度范围内，利用液氮恒温器测量了不同直径的单根纳米管的热导率。已经证实，碳纳米管在300 K附近具有约2000 W/mK的渐近值。（7）对碳纳米管导热系数的测量结果进行了不确定度分析。本方法的适用性已得到证实，并发表了一些关于测量值的新知识。少

(1)Measurements of the thermal conductivity of individual carbon fibers under different manufacturing conditions have been carried out. The effects of heat treatment temperature on the thermal conductivity have been clarified. The measured results show that the thermal conductivity greatly increases as the heat treatment temperature increases, and even up to several hundred times when the temperature is changed from 700℃ to 3000℃. The effects of heat treatment temperature on the microstructure of the cross-sectional surface of individual carbon fibers have been clarified.(2)Measurements of the thermal conductivity and thermal diffusivity of packed carbon fibers at the different packed densities have been carried out. The thermal conductivity of the packed carbon fibers depends greatly on the packed density. The relationship between the thermal conductivity and the packed density has been clarified, and further the electrical conductivity of the packed carbon fibers has been measured ac … More curately.(3)With the help of Micro-Electro-Mechanical Systems (MEMS), the probe used for carbon fibers has been microminiaturized to be applicable for measurements of the nanoscale samples. The nanofilm probe with 100 nm wide, 40 nm thick, and 6 μm long in the part of hot wire has been micro fabricated successfully. It has been confirmed that this nanoprobe can be used to measure the thermal conductivity of a carbon nanotube with its diameter at the dozens of nanometers.(4)By using local focused electron beam irradiation inside a manipulation SEM of the National Institute of Advanced Industrial Science and Technology, one end of the carbon nanotube has been successfully attached to the center part of the nanoprobe to make a T-type nanosensor.(5)Before measuring the thermal conductivity of individual carbon nanotubes, the thermal conductivity and electrical conductivity of the platinum nanofilm must be known and these values have been measured accurately. The both of present measured values for the nanofilm are found to be less than half of the bulk values.(6)Using the variable temperature liquid nitrogen cryostat, the thermal conductivity of individual nanotubes with different diameters has been measured in the range of 100-320 K. It has been confirmed that the carbon nanotube has an asymptotic value of about 2000 W/mK near 300 K.(7)Uncertainty analysis for the measurements of the thermal conductivity of carbon nanofiber and nanotube has been performed. The applicability of the present method has been confirmed and some new knowledge on the measured values has been published. Less