Netsu Sokutei
Online ISSN : 1884-1899
Print ISSN : 0386-2615
ISSN-L : 0386-2615
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Volume 40, Issue 3
Displaying 1-6 of 6 articles from this issue
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Review
  • Simultaneous Acquisition of Temperature and Structural Information by X-Ray Diffraction and DSC
    Akira Kishi
    2013 Volume 40 Issue 3 Pages 92-99
    Published: July 25, 2013
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.40.3_92
    JOURNAL FREE ACCESS
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    Simultaneous measuring instrument for X-ray diffractometry and DSC has been developed to simultaneously acquire temperature and structural information. This instrument, XRD-DSC, is very effective especially for the R&D of pharmaceuticals, and organic and inorganic molecules. 5 to 10mg powder specimen is used for XRD-DSC measurement in the temperature range of -40 to maXimum 350 ℃. X-ray scanning range is 1.5 to 60°/2θ. Using XRD-DSC many kinds of specimen can be measured not only under dry gas flow, but also under high humidity nitrogen gas flow. Besides conventional scintillation counter, high sensitive one- and two-dimensional detectors are widely used today. In this paper following applications are introduced: Different phase transition behavior of tolbutamide deposited from two different solvents. Phase transition of n-dotriacontane and liquid crystal TBBA. Influence of humidity on de-hydration and re-hydration of trehalose. Detail observation of phase change reaction of tripalmitin by two-dimensional X-ray detector.
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  • Study of Ion Conductors by Using in situ Measurements of Synchrotron X-ray and Neutron
    Takanori Itoh
    2013 Volume 40 Issue 3 Pages 100-106
    Published: July 25, 2013
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.40.3_100
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    Recently, Solid Oxide Fuel Cell (SOFC) with high efficiency is promising for improving energy problems. However, the prevalence of using SOFC has important technical issues. One of the most important issue is to make the operating temperature lower under 600 ℃. It is indispensable for solving this issue to understand the conduction mechanism of SOFC materials. However, it has not been sufficient for discussing it to estimate materials properties yet. Especially, there are few reports on the study of the conduction mechanism for SOFC materials by estimating detailed crystal and local structure. In this study, the conduction mechanism in cathode of perovskite materials, as bottleneck for operating at low temperature, is discussed by the results of Rietveld refinements and Maximum Entropy Method, using diffraction data of synchrotron X-ray and neutron, X-ray absorption spectra of in situ measurements and first principle calculations.
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  • Cyclic Oligomers via Hydrogen Bonds in Organic Liquids
    Shigenori Nagatomo, Yasuhisa Yamamura, Kazuya Saito
    2013 Volume 40 Issue 3 Pages 107-113
    Published: July 25, 2013
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.40.3_107
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    Molecular association is ubiquitous in hydrogen-bonding (H-bonding) liquids and is believed to play crucial roles in the determination of their physical properties. Although systems consisting of small and simple molecules are generally preferable for detailed studies from the basic point of view, this is not the case here because such molecules possibly form extending networkand/or chains through H-bonds, thus resulting in complexity and difficulty. Based on a thermodynamic discussion, a simple model is proposed of associating liquids in which small cyclic oligomers are preferably formed. Characteristic temperature dependences in thermodynamic, dielectric and spectroscopic (FT-IR and 1H NMR) properties of liquids of some alcohols with bulky substituents are well described by the model.
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  • Computer Simulation of Solubilization
    Kazushi Fujimoto
    2013 Volume 40 Issue 3 Pages 114-119
    Published: July 25, 2013
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.40.3_114
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    In order to clarify the solubilization at a molecular level, free energy of transfer of methane, ethane, butane, hexane, and octane as well as amphiphilic molecule such as methylamine, octylamine, methanol, and octanol from water phase to a sodium dodecyl sulfate (SDS) micelle has been calculated by thermodynamic integration method combined with molecular dynamics calculations. The free energy of transfer of all alkanes was negative, that is, the alkanes in the SDS micelle are more stable than in the water phase avoiding contact with water molecules. Further, the free energy decreases almost linearly as a function of the number of carbon atoms of alkanes with a decrement of 3.3 kJ mol-1 per one methylene group. The free energy of methylamine, octylamine, methanol, and octanol from the water phase to the SDS micelle is all negative. Further the methane and octane molecule are found in the SDS micelle core. The methylamine was adsorbed on the SDS micelle surface. The methanol is found everywhere in the system from the SDS micelle core to the water phase. The octylamine and octanol are solubilized in the SDS micelle with palisade layer structure.
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  • Thermodynamic Behavior of Quantum Spin Liquid State with Gapless Excitation Structure in Molecule Based Dimer Mott Insulators
    Satoshi Yamashita
    2013 Volume 40 Issue 3 Pages 120-126
    Published: July 25, 2013
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.40.3_120
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    This article introduces the thermodynamic properties of a quantum spin liquid state. In strongly frustrated antiferromagnetic spin systems, there is possibility of a quantum fluctuated ground state called “quantum spin liquid state”. The absence of candidate materials prevents an intrinsic experimental study of spin liquid problem for more than 30 years. However, in this decade, the quantum spin liquid behavior had been observed in two molecule based charge transfer salts, which form dimerized structure in crystal and show Mott insulating behavior at low temperature. Recently, thermodynamic studies succeeded to discover gapless excitation structure in the quantum spin liquid state in two molecule based charge transfer salts. Since accurate heat capacity measurements can estimate absolute values of heat capacity, the quantitative discussion on coefficient γ in heat capacity had also unveiled Fermi liquid character of quantum spin liquid state despite that this state is insulating in terms of conductivity. These thermodynamic observations would promote quantum spin liquid study to new stage.
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