Development of ac Calorimetric Method for Thermal Diffusivity Measurement I. Contribution of Thermocouple Attachment in a Thin Sample

Hatta, Ichiro; Kato, Ryo; Maesono, Akikazu

doi:10.1143/jjap.25.l493

Cited by 31 publications

(11 citation statements)

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“…One disadvantage of the 3 technique is that for a layered, anisotropic crystal the heater's oscillating temperature will be a function of the geometric mean of the "in-plane" and transverse thermal conductivities, 15 so the two components are not separately determined; in addition, it may be difficult to apply a low-noise Joule heater to some organic materials without damaging the material. Alternatively, other investigators have used chopped light to apply oscillating power to one surface of the sample and measured the oscillating temperature at different positions and/or frequencies; [6][7][8][9][10][12][13][14] the frequency dependent response is a function of the thermal diffusivity, D  /c, where c is the specific heat,  the mass density, and  the thermal conductivity. Most commonly, the oscillating temperature is measured on the opposite surface as a function of the lateral distance from the light, either by screening the light from part of the sample [8][9][10]14 or by using a laser to illuminate a small spot.…”

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confidence: 99%

Interlayer thermal conductivity of rubrene measured by ac-calorimetry

Zhang

Brill

2013

Journal of Applied Physics

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We have measured the interlayer thermal conductivity of crystals of the organic semiconductor rubrene, using ac-calorimetry. Since ac-calorimetry is most commonly used for measurements of the heat capacity, we include a discussion of its extension for measurements of the transverse thermal conductivity of thin crystals of poor thermal conductors, including the limitations of the technique. For rubrene, we find that the interlayer thermal conductivity,  0.7 mW/cm·K, is several times smaller than the (previously measured) in-layer value, but its temperature dependence indicates that the interlayer mean free path is at least a few layers.2

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confidence: 99%

Interlayer thermal conductivity of rubrene measured by ac-calorimetry

Zhang

Brill

2013

Journal of Applied Physics

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“…The contribution of an adhesive that attaches the thermocouple to the sample is discussed. 12 Another non-negligible effect when a thermocouple is used as the temperature detector is the time delay in measuring the temperature. Based on system design that takes into account the time delay affect, when the impulse thermal energy, represented by Eq.…”

Section: ͑20͒mentioning

confidence: 99%

Thermal diffusivity measurement of single fibers by an ac calorimetric method

Yamane

Katayama

Todoki

et al. 1996

Journal of Applied Physics

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Analysis of ac temperature wave during the measurement of thermal diffusivity of twolayered platelike samples An ac calorimetric method is applied to the direct measurement of thermal diffusivity of single fibers. Theoretical analysis is presented, taking into account the two-dimensional ac thermal wave for cylindrical systems and the effect of time delay at the temperature detecting system. Experimental tests are performed using nickel and stainless steel wires about 20 m in diameter. The thermal conductivity of fibers about 10 m in diameter of the advanced materials, polyacrylonitrile-based carbon, TORAYCA, and aramide, Kevlar, is determined. The relationship between the thermal conductivity and electric conductivity and the crystalline size of these fibers is discussed. For composite materials made of carbon fibers, the observed thermal conductivity agrees with the thermal conductivity estimated using the values determined by the present method.

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“…An AC calorimetry technique was first developed for the determination of thermal diffusivity of metal film by Hatta et al (1985Hatta et al ( , 1986Hatta et al ( , 1987. The thermal diffusivity of polypyrrole has been determined using a modified AC calorimetry technique, where a small bead thermistor was employed as the temperature sensor.…”

Section: Are Conducting Polymers Metals?mentioning

confidence: 99%

Technical Review : Conducting Polymer Electronics

Unsworth¹,

Lunn²,

Innis³

et al. 1992

Journal of Intelligent Material Systems and Structures

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Before conducting polymers can be employed in many applications, some of the intrinsic properties of these materials need to be better understood. An overview of the research and development of conducting polymers being undertaken at UTS is presented. Because conducting polymers are difficult to process once fabricated, an understanding of synthesis parameters and the use of synthesis techniques to produce conducting polymer films with desired properties is of the upmost importance. Descriptions of the galvanostatic and potentiostatic techniques employed to produce polyheterocyclics are presented. Thermal properties such as thermal diffusivity, thermal conductivity and specific heat are being investigated. Preliminary results reveal that the thermal diffusivity of polypyrrole is higher than that achieved with traditional polymers. The nature of contacts and junctions with polypyrrole and poly(3-methylthiophene) are discussed. High work function metals form ohmic junctions with polypyrrole while aluminium forms a Schottky barrier with poly(3-methylthiophene). Microwave studies on polypyrrole films reveal that the microwave transmission and reflection are dependent upon the doping level of the film. Applications of the conducting polymers in data security modules and for light weight electrically conducting wires are also illustrated.

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Development of ac Calorimetric Method for Thermal Diffusivity Measurement I. Contribution of Thermocouple Attachment in a Thin Sample

Cited by 31 publications

References 1 publication

Interlayer thermal conductivity of rubrene measured by ac-calorimetry

Interlayer thermal conductivity of rubrene measured by ac-calorimetry

Thermal diffusivity measurement of single fibers by an ac calorimetric method

Technical Review : Conducting Polymer Electronics

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