Netsu Sokutei
Online ISSN : 1884-1899
Print ISSN : 0386-2615
ISSN-L : 0386-2615
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Volume 36, Issue 2
Displaying 1-8 of 8 articles from this issue
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Preface
Review
  • Calorimetric Investigations of Molecular Recognition in Solution
    Takayoshi Kimura
    2009 Volume 36 Issue 2 Pages 72-82
    Published: March 31, 2009
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.36.2_72
    JOURNAL FREE ACCESS
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    In order to clarify the molecular recognition appeared as total of the interaction between molecules in solution, it is very important to understand the interaction between molecules based on the slightly different in the molecular structure. Excess enthalpies of systems of enantiomers, o-, m-, p-isomers, isotopes have been measured by precise microcalorimetry. The results were contributed to verify the solution theory and summarize between the structures of the molecules constituted solution and the properties of solution. The major interactions of these systems were classified from cohesive energy density or dipole-dipole interaction parameters. Moreover, the effect of non-polar interactions and polar interactions were clarified from the enthalpies of mixing with amphipathic FAMSO and DMSO and compounds which designed systematically polar functional groups and non-polar ones such as aliphatic compounds, and the results about the molecular structure of the aliphatic compound in solution were introduced.
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  • Novel High-Temperature Fixed Points of Metal-Carbon Alloys
    Naohiko Sasajima
    2009 Volume 36 Issue 2 Pages 83-90
    Published: March 31, 2009
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.36.2_83
    JOURNAL FREE ACCESS
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    Above the freezing temperature of silver, the International Temperature Scale of 1990 (ITS-90) is defined using Planck's law of blackbody radiation. Since the temperature is determined by ratio of its emitted radiance against the radiance from Ag, Au, or Cu freezing-point blackbody, uncertainty of the scale increases rapidly with increasing temperature. To solve this problem, AIST has been developing high-temperature fixed points of metal-carbon alloys. In this text, introduction of ITS-90 and high-temperature fixed point using metal-carbon alloys, melting and freezing behaviors of these fixed points under various conditions, and application of these fixed points for thermocouple calibration are presented.
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  • Phase Transition of Frustrated Spin Systems
    Shu Tanaka, Norikazu Todoroki
    2009 Volume 36 Issue 2 Pages 91-97
    Published: March 31, 2009
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.36.2_91
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    Phase transition of frustrated systems is very important topic and interesting phenomenon. In frustrated systems, the specific heat shows characteristic behavior due to many degenerate ground states. We review the feature of the phase transition and that of frustrated systems in a viewpoint of the entropy. We also review interesting phenomena of the stacked triangular antiferromagnets and that of the kagome antiferromagnets with easy axis anisotropy. Finally, we show recent studies of frustrated spin systems.
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  • Ionic Liquids from the Viewpoint of Thermal Phenomena : Unique Thermal Behaviors on Melting and Crystallization
    Keiko Nishikawa, Takatsugu Endo
    2009 Volume 36 Issue 2 Pages 98-104
    Published: March 31, 2009
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.36.2_98
    JOURNAL FREE ACCESS
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    We studied melting and crystallization behaviors of some imidazolium-based ionic liquids using a laboratory-made differential scanning calorimeter (DSC) with nano-Watt stability and sensitivity. In addition to common behaviors for many ionic liquids such as pre-melting over a wide temperature range and excessive super-cooling, we observed unique thermal phenomena: reversible phase transitions of domains in the pre-melting region, rhythmic crystallization and melting, and intermittent crystallization. The last two phenomena of them were observed in the experiments at extremely slow heating/cooling rates. It is considered that they occur because an imidazolium-based cation is capable of taking plural stable conformations and the conformational changes occur linking with melting and crystallization. We interpret these curious phenomena as the phase changes of the locally melted domains composed of different conformers, which significantly hinders the phase changes.
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  • An Insect Life during Dry Season － Glassy Trehalose Acts as Water Replacement －
    Takao Furuki, Takashi Okuda, Takahiro Kikawada, Minoru Sakurai
    2009 Volume 36 Issue 2 Pages 105-111
    Published: March 31, 2009
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.36.2_105
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    Anhydrobiosis is an extremely dehydrated state in which organisms show no detectable metabolism with the ability to revive upon immersion into water. Larvae of an African chironomid, Polypedilum vanderplanki, are the largest multicellular animal capable of anhydrobiosis. Recently we have successfully clarified the physicochemical mechanism of their anhydrobiosis. When larvae of P. vanderplanki fell into an anhydrobiotic state, they accumulated endogenously non-reducing disaccharide, α,α-trehalose, as high as 25 % of their dry body mass, which was found to be uniformly distributed throughout the dehydrated body by Fourier transform infrared (FT-IR) microscopic mapping image. Differential scanning calorimetry measurements indicated that the anhydrobiotic larvae were in a glassy state up to ca. 65 ℃. Changing from the glassy to rubbery state by either heating or allowing slight moisture uptake led to their very poor survival ability. FT-IR spectra showed that the cellular membrane of the anhydrobiotic larvae remained in the liquid-crystalline state throughout formation of hydrogen bonds between its phospholipids and the endogenous trehalose. Taken these findings together we concluded that trehalose plays important roles in biological glass formation as the water replacement, although other compounds would be also involved in these phenomena.
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  • Characterization of Frozen Aqueous Solution for Formulation and Process Design of Freeze-dried Pharmaceuticals
    Ken-ichi Izutsu
    2009 Volume 36 Issue 2 Pages 112-120
    Published: March 31, 2009
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.36.2_112
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    Freezing of aqueous solutions concentrates solutes into highly viscose phases surrounding ice crystals. Various solutes have different tendencies to crystallize or remain amorphous in the frozen solutions. Thermal analysis of the frozen solutions shows highest critical product temperatures (Tg', Tc, Teu) required to retain the products from physical collapse or melt-back phenomena during the primary drying process. Hydrogen-bondings and electrostatic interactions between multiple solutes affect the eutectic crystallization and the transition temperatures of frozen solutions. Application of the thermal analysis to formulation and process design of freeze-dried pharmaceuticals was discussed.
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