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Journal of Thermal Analysis and Calorimetry
Authors: T. Tanaka, J. Magoshi, Y. Magoshi, S. ichi Inoue, M. Kobayashi, H. Tsuda, M. Becker, and Sh. Nakamura

Abstract  

The thermal properties of liquid silk from domestic and wild silkworms are investigated. Liquid silks obtained from the silk gland of the domesticated silkworm, Bombyx mori and four wild silkworms, Samia cynthia ricini, Dictyoploca japonica, Antheraea pernyi and Antheraea yamamai were used. The DSC curves for the liquid silk from the domestic silkworm have weak endothermic peaks corresponding to the breaking of hydrogen bonds in the β-form or to the untangling of physical network. The DSC curves for the wild silkworm silks, however, show clear exothermic peaks corresponding to a phase transition from the α-helix conformation to the β-form. Liquid silk from all the different silkworms undergoes a characteristic irreversible phase transition.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Y Kobayashi, M. Kubo, Y. Yamada, T. Saito, H. Ueno, H. Ogawa, W. Sato, K. Yoneda, H. Watanabe, N. Imai, H. Miyoshi, and K. Asahi

Abstract  

In-beam Mössbauer spectra of 57Fe, decayed from short-lived 57Mn (T1/2 = 1.45 min) implanted into potassium permanganate, KMnO4, were measured at temperatures between 11 K and 130 K. This is the first application of a secondary RI beam to the study of valence states after nuclear transformation. The in-beam Mössbauer spectra obtained below 90 K could be analyzed with two components, a doublet and a singlet. From the calculations of the molecular orbital wave functions, the singlet is suggested to be substitutional 57Fe atoms for Mn-sites in tetrahedral [MnO4] with an unusually high valence state of Fe8+.

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Journal of Thermal Analysis and Calorimetry
Authors: T. Tanaka, J. Magoshi, Y. Magoshi, B. Lotz, S.-I. Inoue, M. Kobayashi, H. Tsuda, M. Becker, Zh. Han, and Sh. Nakamura

Abstract  

The crystal structure, thermal properties and growth rates of spherulites of the Tussah silk fibroin, produced upon drying of the silk taken directly from the lumen which is essentially a poly(L-alanine)polypeptide, are investigated. Depending on casting conditions, spherulites with either αhelical chain conformation or β parallel sheet structure are produced. The growth rates display a strong positive temperature coefficient, with an apparent transition, which however cannot be related with the formation of two different crystal structures at this stage.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: W. Sato, H. Ueno, H. Watanabe, H. Ogawa, H. Miyoshi, N. Imai, A. Yoshimi, K. Yoneda, D. Kameda, Y. Kobayashi, and K. Asahi

Abstract  

A new 19F probe disintegrated from short-lived 19O has been developed for the first time for time-differential perturbed angular correlation method. The angular correlation coefficient for the relevant cascade has been experimentally estimated to be A22 = -0.17±0.01. As the first application of this technique to condensed matter physics, the probe was implanted in polycrystalline fullerene C60. We have observed two contrastive perturbations acting on the probe nuclei, which reflect electrostatic and dynamic interactions with the extranuclear field.

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Journal of Thermal Analysis and Calorimetry
Authors: M. Wang, Y. Sawada, K. Saito, S. Horie, T. Uchida, M. Ohtsuka, S. Seki, S. Kobayashi, T. Arii, A. Kishi, T. Takahashi, Y. Nishimoto, T. Wakimoto, K. Monzen, I. Kashima, T. Nishikiori, L. Sun, and R. Ozao

Abstract  

The thermal change of the tris(8-hydroxyquinolinato)aluminum (Alq3) is currently investigated by XRD-DSC and TG. The phase transition of Alq3 from α-phase to γ-phase takes place at 643–669 K. A very sharp peak with the peak temperature at approx. 709 K is ascribed to the melting of the Alq3. The decomposition of the Alq3 was observed accompanied with the melting and evaporation at >703K. The effect of the atmospheres on the mass loss procedure was studied by TG. It was found that thermal process of Alq3 was strongly influenced by the partial pressure of water vapor in the atmosphere instead of oxygen.

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