Rev. High Pressure Sci. Technol.

Vol.8  No.4(1998) Abstract

Rev. High Pressure Sci. Technol. 8-4,243-250(1998)
Monte Carlo Simulation for Supercritical Fluids + High-Boiling Compounds Systems
山本盛夫   岩井芳夫
The Monte Carlo method has been applied to calculate the solubilities (gas-solid equilibria) of high-boiling compounds (aromatic compounds, higher alcohols, and higher fatty acids) in supercritical fluids. Supercritical fluids were treated as single site molecules, and high-boiling compounds were treated as multisite molecules. The solubilities of aromatic isomers in supercritical carbon dioxide can be quantitatively distinguished by a group contribution site model without any binary interaction parameters. The structures of supercritical carbon dioxide around aromatic isomers are found to be different because of the screen effect of the substituents. The radial distribution functions of supercritical fluids and mean-square end-to-end separations for chain molecules have been reported as fundamental knowledge of the microstructure of chain molecules in the supercritical fluid phase.

[Monte Carlo Simulation, Supercritical Fluid, Solubility, High-boiling Compound, Radial Distribution Function]
〒812-8581 福岡市東区箱崎6-10-1 九州大学大学院工学研究科化学システム工学専攻
Department of Chemical Systems and Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan

Rev. High Pressure Sci. Technol. 8-4,251-259(1998)
Numerical Simulations of Shocks in Fluids and Solids
片山 雅英
After an overview of the formulation of hydrocodes applied to the numerical simulation of the shock and pressure waves in solid, liquid and gas phases of materials, several examples of hypervelocity impact and explosion analyses are shown and discussed partly as compared with corresponding experimental results.

[hydrocode, Eulerian, Lagrangian, explicit solution scheme, smoothed particle hydrodynamics, hypervelocity impact, detonation, space debris]
〒136-8581 東京都江東区南砂2-7-5 (株)CRC総合研究所
CRC Research Institute, Inc., 2-7-5 Minamisuna, Koto-ku, Tokyo 136-8581

Rev. High Pressure Sci. Technol. 8-4,260-267(1998)
Simulation of Powder Behaviour during Compaction based on Continuum and Discrete Modelling
島 進  小寺 秀俊
Susumu SHIMA Hidetoshi KOTERA
In powder forming processes, the behaviour of powders during compaction, such as the mechanisms of density increase, density distribution, evolution of anisotropy, the shape of compacts in isostatic compaction, etc. significantly influence the quality of the products, dimensional and geometrical accuracy and material consumption. Further, the compacts that have been compacted at room temperature are subject to a sintering process; they undergo dimensional and geometrical change during the process; these are affected by the previous compaction process and density distribution. In recent years, the demand has been increasing for accuracy in the dimensions and shapes of products. Simulation of compaction behaviour of powders is, thus, of great importance for near net shape production. To simulate the behaviours of powders or granular materials, there are two approaches: one is to treat the powder based on continuum mechanics, and the other is to observe the movement of individual particles. In this article, we shall overview the state of the art regarding both types of simulation.

[simulation, FEM, discrete modelling, powder compaction, isostatic pressing, die pressing, constitutive equations]
〒606-8501 京都市左京区吉田本町 京都大学大学院工学研究科機械工学専攻
Department of Mechanical Engineering, Kyoto University Sakyo-ku, Kyoto, 606-8501, Japan

Rev. High Pressure Sci. Technol. 8-4,268-272(1998)
Theoretical Design of BCN Heterodiamond
常行 真司 館山 佳尚
A computational-physics approach to design and prediction of hypothetical BCN heterodiamonds is reviewed. A probable heterodiamond BC2N structure that can be obtained from the compression of graphitic BC2N at low temperature is proposed using first-principles calculations. The structure, which has a large bulk modulus comparable to that of diamond as well as a wide band gap, can also be synthesized from a superlattice of graphite and hexagonal BN monolayers, suggesting that we could design a variety of polytypes.

[diamond, high-pressure synthesis, computer-aided design, structural transformation, electronic structure]
〒106-8666 港区六本木7-22-1 東京大学物性研究所
Institute for Solid State Physics, University of Tokyo, Roppongi, Minato-ku, Tokyo 106-8666

Rev. High Pressure Sci. Technol. 8-4,273-279(1998)
Estimation of Stress Distribution of Pressure Media in a Flat Belt Type High Pressure Apparatus by the Rigid Plastic Method
佐藤 周一 中島 猛 中村 裕一*
A stress distribution of pressure media in the high pressure apparatus, flat belt type, was estimated by rigid plastic method. Since it was so difficult to estimate the stress distribution of that primarily, because of the complicated inner structure of the pressure media, we tried to estimate stress distribution in diamond anvil cell that had a simple structure. Various kinds of pressure media , copper, pyrophyllite and salt , were used to study the effect of friction factors. The estimated stress distribution of copper in a diamond anvil cell was quite similar to the observed one, when the friction factor was supposed to be a constant at any inner pressure. On the other hand, the estimated stress distribution of pyrophyllite became equal to the observed one, when the friction factor was supposed to be proportional to the 3rd power of an inner pressure.
Finally, the estimated stress distribution of pressure media in the high pressure apparatus could be equal to the observed one using supposition of the friction factor being proportional to the 3rd power of an inner pressure.

[high pressure apparatus, rigid plastic method, finite element method, pressure media, friction factor]
〒664-0016兵庫県伊丹市昆陽北1-1-1 住友電気工業株式会社 伊丹研究所
Itami Research Laboratories, Sumitomo Electric Industries LTD, 1-1-1,koyakita,Itami, Hyogo, 664-0016
*〒514-8507 津市上浜町 1515 三重大学工学部 物理工学科 ナノプロセッシング
Faculty of Engineering, MIE University, 1515, Kamihama-cho ,Tsu, Mie, 514-8507

Rev. High Pressure Sci. Technol. 8-4,280-286(1998)
―混合原子価錯体 Cs2AuIAuIIIX6 の結晶構造―
Single Crystal X-Ray Structure Analysis under High Pressure Using He Gas as a Pressure
Transmitting Medium ― Crystal Structure of Mixed-Valence Complexes Cs2AuIAuIIIX6
In this report, a technique of single crystal X-ray diffraction measurements under high pressures, using a diamond-anvil-cell with helium gas as an inert and hydrostatic pressure-transmitting medium, is introduced. The technique has been applied to three-dimensional halogen-bridged mixed-valence gold complexes, Cs2AuIAuIIIX6 (X=Cl, I) to investigate the mixed-valence state and the crystal structure under high pressures up to 18 GPa and 7.5 GPa, respectively. The pressure dependences of the unit cell parameters indicate that structural phase transitions occur from tetragonal to cubic at 12.5 GPa for the Cl-bridged complex, and from tetragonal to monoclinic at 6.0 GPa for the I-bridged complex. The Cl-bridged complex in the higher pressure phase has a space group, Pm3m and the cubic Perovskite-type structure.

[DAC, high pressure, helium gas pressure-transmitting medium, single crystal, X-ray diffraction, mixed valence, gold complexes, Perovskite structure, phase transition]
〒153-8902 東京都目黒区駒場3-8-1 東京大学大学院総合文化研究科広域科学専攻相関基礎科学系・化学
Department of Chemistry, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, 3-8-1, Meguro, Tokyo 153-8902

Rev. High Pressure Sci. Technol. 8-4,287-293(1998)
溶液中における一重項酸素の寿命と反応性― 高圧力効果からのアプローチ
Lifetime and Reactivity of Singlet Oxygen in Solution - Approach from High Pressure Study
Singlet oxygen, 1O2(1△g), which is the lowest electronically excited state of the oxygen molecule, is quenched by various compounds. In this article, the pressure effects on the physical quenching of 1O2(1△g) by solvent molecules and amines, and also on the chemical reactions of 1O2(1△g) with furans and tetramethylethylene (TME) (ene reaction) in liquid solution are reviewed. For these systems, the quenching mechanism is described.

[singlet oxygen(1△g), high pressure, bleaching of DPBF, luminescence, physical quenching, chemical reaction]
〒606-8585 京都市左京区松ケ崎橋上町 京都工芸繊維大学工芸学部
Faculty of Engineering and Design, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585

Rev. High Pressure Sci. Technol. 8-4,294-301(1998)

  Microbial Activities under High Pressure: Calorimetry of Pressure-Shocked Yeast and Biostimulation Effect of Laser Irradiation
田村勝弘 宮下充雄
Biocalorimetry is one of powerful and convenient tools to evaluate microbial activities under high pressure. The method is mainly based on the fact that the heat evolved is strictly proportional to the metabolic activity, and the magnitude of calorimetric signal is employed as an index to express the biological activities. This method was adopted in order to investigate the thermotolerance of heat- and pressure-shocked yeast. The effects of the non-reducing disaccharide trehalose on the stress response of yeast were also studied by colony counting method and calorimetry. The biostimulation effect of He-Ne laser was used for the recovery of yeast activity under high pressure up to 100MPa. At 50MPa and 30℃, the growth of unirradiated yeasts was inhibited entirely, however, the viable cell numbers of irradiated ones were increased and the rate of the increase in number of viable cells corresponded to that of the inrradiated ones at 0.1MPa.

[calorimetry, yeast, pressure shock, laser, thermotolerance, trehalose, microbial activity, heat shock]
〒770-8506 徳島市南常三島町 2-1 徳島大学工学部化学応用工学科
Department of Chemical Science and Technology, Faculty of Engineering, The University of Tokushima, Minamijosanjima-cho, Tokushima 770-8506

Rev. High Pressure Sci. Technol. 8-4,302-305(1998)
Dynamic strength of spherical shells under internal explosive loading
A. G. Ivanov, M. A. Syrunin, A. G. Fedorenko
The paper presents the results of experiments for determination of response of spherical shells having load-bearing layer from fiber glass under radially symmetrical inner explosive loading. We carried out assessment of dynamic strength of two shell types with diameter of 500 mm, which differed in the scheme of fiber glass layer coiling. It was demonstrated that a shell with more even theikness (of 15-20 mm)of load-bearing fiber glass layer has significant advantage. Such a sheath has approximately twofold reserve of strength during explosion of a charge equal in energy to 1.4 kg of trinitrotoluene in its geometrical center. It has been found that transition from one-axial strains, which are reallized under explosive loading of a cylindrical shell, to two-axial strains, when spherical shells are used, does not change the value of limiting strains of fiber glass(on the destruction threshold). This value is determined by limiting strains of a glass thread. It is equal to 4-5 %. Tested spherical shells from fiber glass reinforced by steel layer allow to obtain record high value of the explosion-proofness property, i, e. relation between the high-explosive charge mass, where explosion of this high-explosive charge is confined inside of the sheath caviity, and mass of this shell. It is equal to 3-6 %.

[shell, fiber glass, explosive loading, strain, deformation, strength, container]
All-Russian Scientific Research Institute of Experimental Physics, 607190, Sarov, Nizhni Novgorod region, Russia

Rev. High Pressure Sci. Technol. 8-4,306-308(1998)
Superdense State of Metals Compressed by Shock Waves
R. F. Trunin
The paper presents explosive devices designs for generation of strong shock waves. Record values of specific internal energy of shock-compressed iron are obtained with use of them.

[compression, shock waves, energy, pressures, iron]
RFNC-VNIEF. Sarov. Russia

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