Journal of the Japanese Society for Experimental Mechanics
Print ISSN : 1346-4930
ISSN-L : 1346-4930
Current issue
Special Issue on Considering Material Characterization Technology Finding from the Past
Displaying 1-9 of 9 articles from this issue
Foreword
Special Issue on Considering Material Characterization Technology Finding from the Past
Review
  • Hidemasa TSUNEISHI
    2025 Volume 25 Issue 1 Pages 3-7
    Published: 2025
    Released on J-STAGE: July 15, 2025
    JOURNAL FREE ACCESS

    Scanning probe microscopy, which includes scanning tunneling microscopy and atomic force microscopy, is used as a technique for observing surface morphology with high spatial resolution. In recent years, by taking advantage of the characteristic of being able to touch extremely small areas with a solid probe, it has been used not only for microscopy but also as a method for evaluating material properties. In this article, we use lithium-ion batteries as an example to introduce an analysis example of the causes of increased electrical resistance inside composite materials, as well as an analysis example of the mechanical properties of materials in the case of single particle samples and pressed powder samples.

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Original Papers
  • Tsuyoshi NISHI, Satoru NISHIWAKI, Hiromichi OHTA, Chihiro IWAMOTO, Kot ...
    2025 Volume 25 Issue 1 Pages 8-13
    Published: March 19, 2025
    Released on J-STAGE: July 15, 2025
    JOURNAL FREE ACCESS

    BaTiO3/epoxy composite, which is expected to generate power through temperature changes, is currently being researched and developed for practical applications. However, the temperature dependence of their thermophysical properties, such as the thermal conductivity and thermal expansion coefficient, remains to be elucidated. In this study, we measured the thermal diffusivity and specific heat capacity using the flash method, and measured the density using the Archimedes method, and used all the measured values to determine the thermal conductivity of the BaTiO3/epoxy composite. Using the results of thermal conductivity, the temperature dependence of thermal conductivity and volume fraction of the filler (BaTiO3 particles) were determined. Subsequently, the thermal conductivities of the BaTiO3/epoxy composite were estimated to be using a theoretical model. In this result, Kananari's model was found to be effective for estimating the thermal conductivities of these samples.

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  • Yuna NAKAYAMA, Naoto KUDO, Naoki KUROIWA, Rie ENDO, Hiromichi OHTA, Ts ...
    2025 Volume 25 Issue 1 Pages 14-17
    Published: March 19, 2025
    Released on J-STAGE: July 15, 2025
    JOURNAL FREE ACCESS

    Accurate measurement of the thermophysical properties of lunar regolith is essential for the success of lunar missions. However, reliable data on the specific heat of lunar regolith simulants, such as FJS-1 and JSC-1A, are currently unavailable. Wakabayashi et al. measured the specific heat (Cp) of FJS-1. The specific heat of JSC-1A can be calculated from the volumetric heat capacity (ρCp) reported by Pinheiro et al. and the density (ρ) reported by Meurisse et al. A comparison of the specific heat values for FJS-1 and JSC-1A revealed significant discrepancies even though both of them simulate mare regolith. In this study, the accuracy of specific heat measurements was first validated using single-crystal silicon with temperature-modulated differential scanning calorimetry (TM-DSC). Then, the specific heat of FJS-1 and JSC-1A was measured using both TM-DSC and the adiabatic continuous method. As a result, the specific heat values for FJS-1 and JSC-1A obtained using the two methods were consistent. It was also found that the specific heat of the two simulants was nearly identical within the tested temperature range. This consistency suggests that the specific heat values obtained by TM-DSC are reliable, as there is no significant difference in the specific heat of FJS-1 and JSC-1A.

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  • Yuichiro KOIDE, Chihaya FUJIWARA, Tomoko SHIRAHASE, Kazutaka ISODA
    2025 Volume 25 Issue 1 Pages 18-22
    Published: March 19, 2025
    Released on J-STAGE: July 15, 2025
    JOURNAL FREE ACCESS

    In this study, a film was made by melt-kneading TiO2 with PC for the purpose of evaluating the haze of opaque samples. In the existing haze standard ISO14782 (JIS K 7136), all opaque samples showed the same value of about 100%. Based on the definition of haze value and scattering theory, measurements were performed under the hypothesis that haze evaluation would be possible by using a light source in the infrared range, which has a longer wavelength than the visible light range. As a result, opaque samples showed haze values corresponding to the amount of TiO2 compounded. To examine the factors that made haze measurement possible, the size of the filler contained in each sample was compared with the measurement wavelength, and it was confirmed that haze measurement was possible by using a wavelength larger than the filler size. From these findings, it was clarified that haze evaluation of opaque samples, which is difficult to evaluate using existing standards, can be performed by measuring haze using infrared rays, and that the value can obtain information that reflects the internal state of the composite material.

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  • Daiki TANISAWA, Yoshiyuki SHINOZAKI, Masayuki TAKASHIRI
    2025 Volume 25 Issue 1 Pages 23-28
    Published: March 19, 2025
    Released on J-STAGE: July 15, 2025
    JOURNAL FREE ACCESS

    Amorphous and nanocrystalline silicon are valuable materials in many fields such as semiconductors, sensors, and thermoelectric devices. The thermal transport properties of silicon are not well understood compared to its electrical transport properties. Although it is known that thermal conductivity increases during the phase transition from amorphous to nanocrystalline silicon, the detailed mechanism of the increase has not been investigated. Therefore, we investigated detailed thermal transport properties of silicon by 3ω method and nanoindentation. The amorphous silicon thin films were deposited using pressure-gradient sputtering without substrate heating. The nanocrystalline silicon thin films were formed by the post-thermal annealing at 1000°C. The thermal conductivity increased during the phase transition from amorphous to nanocrystalline because the phonon mean free path increased while the sound velocity did not change significantly. The results are useful for understanding the thermal transport properties at phase transitions of many materials.

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  • Taichi MURAKAMI, Masaki SHIMOFURI, Toshiyuki TSUCHIYA, Shugo MIYAKE
    2025 Volume 25 Issue 1 Pages 29-32
    Published: March 19, 2025
    Released on J-STAGE: July 15, 2025
    JOURNAL FREE ACCESS

    In this study, as an approach to improve the potential problem of a noncontact temperature measurement based on Thermoreflectance (TR) method, we attempted to apply a two-wavelength thermoreflectance (2WTR) method to improve sensitivity and uncertainty of measured temperature value. First, we developed an optical system for reflectance measurement by using two laser beams which enable us to measure the two laser beams simultaneously and separately. And then, we try to measure 200 nm thick Au film on Silicon substrate and investigate the temperature dependency of the reflectance coefficient. The measurement results show 1.22 times increase in measurement sensitivity and a 15.8% reduction in temperature uncertainty compared to conventional one wavelength measurements.

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Technical Note
  • Seiichiro SANDOH, Hiromichi OHTA, Tsuyoshi NISHI
    2025 Volume 25 Issue 1 Pages 33-36
    Published: March 19, 2025
    Released on J-STAGE: July 15, 2025
    JOURNAL FREE ACCESS

    In case of the thermal diffusivity measurement such as laser spot periodic heating radiation thermometry method which has laser heating system and non-contact detection system, blackening layer on surface helps heating process but it affects thermal diffusivity analysis because there is interfacial thermal resistance between blackening and sample. In this research, FEM (finite elements method) is applied for replication of interfacial thermal resistance between blackening layer and sample by a laser spot periodic heating radiation thermometry method. The phase difference between periodic heating signals and periodic radiation thermometry signals due to interfacial thermal resistance is observed. It is confirmed that change of the phase difference can be qualitatively replicated by calculation whose parameter is interfacial thermal resistance.

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