The Review of High Pressure Science and Technology
Online ISSN : 1348-1940
Print ISSN : 0917-639X
ISSN-L : 0917-639X
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Volume 22, Issue 2
Displaying 1-13 of 13 articles from this issue
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Foreword
Reviews—Recent Developments of the Studies on the Creation of Nanomaterials by High-Pressure Techniques—
  • Supercritical Hydrothermal Synthesis of Nanoparticles for Hybrid Materials
    —Super Hybrid Materials through Organic Surface Modification—
    Tadafumi ADSCHIRI, Tomohiro ARAI, Yosizumi ISHIKAWA, Masataka UENO, Ma ...
    2012 Volume 22 Issue 2 Pages 89-96
    Published: 2012
    Released on J-STAGE: May 31, 2012
    DOIhttps://doi.org/10.4131/jshpreview.22.89
    JOURNAL FREE ACCESS
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      This paper describes the specific features of supercritical hydrothermal synthesis method for organic modified nanoparticles synthesis and their applications for hybrid materials with polymers. Under the supercritical state, water-organic molecules-inorganic precursors form a homogeneous phase with high concentration, and the water molecule works as an acid or base catalyst. This leads to form optimum conditions for synthesizing organic modified nanoparticles with high concentrations. Also, this method can control the exposed surface, which leads to fabricate a new active catalyst. The formed nanoparticles can be mixed with organic solvents or with polymers, and thus, this method can fabricate new hybrid polymers.
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  • Preparation of Nano-Sized Materials with Pulsed Power Irradiation in Supercritical Fluids
    Mitsuru SASAKI, WAHYUDIONO, Siti MACHMUDAH, Motonobu GOTO
    2012 Volume 22 Issue 2 Pages 97-103
    Published: 2012
    Released on J-STAGE: May 31, 2012
    DOIhttps://doi.org/10.4131/jshpreview.22.97
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      In this paper, we introduce novel findings that we have obtained through the several experimental techniques with high-voltage pulsed power in high-density fluids (such as subcritical water, supercritical carbon dioxide or supercritical argon). In laser ablation in supercritical carbon dioxide, we succeeded in the synthesis of gold nanoparticles from gold substrate. Next, we were able to produce hard amorphous carbon thin film from typical organic chemicals such as phenol and aniline. Furthermore, by using a novel technique “electro-spinning in supercritical carbon dioxide”, we succeeded to prepare unique morphology fibers such as hollow or balloon-like structures in one step.
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  • Development of Particle Coating Technique Using Ultrasonic Cavitation in High-Pressure CO2
    Kiyoshi MATSUYAMA, Kenji MISHIMA
    2012 Volume 22 Issue 2 Pages 104-112
    Published: 2012
    Released on J-STAGE: May 31, 2012
    DOIhttps://doi.org/10.4131/jshpreview.22.104
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      We describe particle coating using ultrasonic irradiation in high-pressure carbon dioxide (CO2). Host microparticles were coated with guest nanoparticles. Shock waves generated by collapsing cavitation bubbles induced with ultrasonic irradiation accelerated the deagglomeration and dispersion of guest nanoparticles, and achieved dry particle coating in liquid CO2. Host microparticles coated with guest nanoparticles were observed using scanning electron microscopy (SEM). This revealed that the guest particles were completely coated with guest nanoparticles, and a smooth coating surface was obtained.
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  • Development of Continuous Production Method of Metal Oxide Nanoparticles Using a Micromixer and High-Temperature and High-Pressure Water
    Kiwamu SUE, Shin-ichiro KAWASAKI
    2012 Volume 22 Issue 2 Pages 113-120
    Published: 2012
    Released on J-STAGE: May 31, 2012
    DOIhttps://doi.org/10.4131/jshpreview.22.113
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      In this article, recent advances in development of continuous production method of high crystallinity metal oxide nanoparticles (NPs) through hydrothermal synthesis using micromixers and high-temperature and high-pressure water are summarized. This method has been attracting much attention as an innovative production technology of desired amount of NPs having desired particle properties for reducing development period of products using NPs and increasing application fields of NPs. Fundamental principle of this method, optimization of mixing condition, reaction rate and equilibrium of hydrothermal synthesis, and advantages of developed micromixers are described.
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  • High-Pressure Synthesis and Properties of Nano-Polycrystalline Super-Hard Materials
    Hitoshi SUMIYA
    2012 Volume 22 Issue 2 Pages 121-128
    Published: 2012
    Released on J-STAGE: May 31, 2012
    DOIhttps://doi.org/10.4131/jshpreview.22.121
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      Single-phase super-hard polycrystalline cBN and diamond have been synthesized by direct conversion sintering from hBN and graphite, respectively, under static high pressure and high temperature. The polycrystalline cBN and diamond consist of fine grains of several tens or hundreds nano-meters, having high hardnesses which are higher than those of their single crystals. They also have high transverse rupture strengths (TRSs) which are much higher than those of conventional sintered compacts containing binder materials. The fine microstructure features without any secondary phases and surpassing mechanical properties of the single-phase super-hard polycrystalline cBN and diamond are promising for applications in next-generation high-precision and high-efficiency cutting tools.
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  • Solvothermal Synthesis of ITO Nanoparticles and Their Application to the Transparent Conductive Film
    Noritsugu KOMETANI, Masaya FUJII
    2012 Volume 22 Issue 2 Pages 129-134
    Published: 2012
    Released on J-STAGE: May 31, 2012
    DOIhttps://doi.org/10.4131/jshpreview.22.129
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      Indium tin oxide (ITO) nanoparticles have been synthesized from the mixed ethylene glycol solution of indium (III) chloride, tin (II) chloride and sodium hydroxide by the solvothermal process with the addition of oleylamine or oleic acid as a protective reagent. The x-ray diffraction patterns of particles synthesized at 250°C show that the ITO begins to be produced after the reaction duration of 6 h when oleylamine is added to the reaction solution, indicating a promoting effect on the ITO formation, whereas only indium oxyhydroxide is formed when oleic acid is used. The transmission electron microscopic observation has revealed that ITO nanoparticles obtained by the addition of oleylamine are monodisperse and their size increases from 4-5 nm to 50-60 nm with elongating reaction duration from 6 to 96 h. ITO thin films are prepared by the multiple deposition of a collodion membrane incorporating synthesized ITO nanoparticles on the glass substrate followed by sintering at 400-500°C. They exhibit a good transparency in the visible region and a specific resistivity as low as 1.0 Ω·cm.
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Review: 2011 JSHPST Award
Review: 2011 JSHPST Award for Young Scientists
Review: 2011 Bridgman Award
  • In Situ High-Pressure Experiment Using the KMA Equipped with Sintered Diamond Anvils
    Eiji ITO
    2012 Volume 22 Issue 2 Pages 164-169
    Published: 2012
    Released on J-STAGE: May 31, 2012
    DOIhttps://doi.org/10.4131/jshpreview.22.164
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      Pressure range of in situ x-ray observation has been extended very close to 100 GPa, by interfacing the Kawai-type multi-anvil apparatus (KMA) equipped with sintered diamond anvils with the synchrotron radiation at SPring-8. High-pressure phase equilibria in Fe2O3 and MgGeO3 are summarized. Isostructural reduction in electrical resistance of hematite by three orders of magnitude at pressures 54-56 GPa strongly suggests the occurrence of a Mott transition. In MgGeO3, special attention was paid to the dP/dT slope of the phase boundary between perovskite and post-perovskite phases. Spin transition of Fe2+ in (Mg0.83Fe0.17)O is also briefly reported.
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