高压物理学报

Calculation of the Strain, Stress and Elastic Energy for - Quartz Transition and Its Geological Significance

ZHOU Wen-Ge, XIE Hong-Sen, ZHAO Zhi-Dan, ZHOU Hui, GUO Jie

2002, 16(4): 241-248 . doi: 10.11858/gywlxb.2002.04.001

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Abstract:
The variations of the lattice parameters of - and -quartz at high pressure and high temperature are calculated with the compressional and thermoelastic properties of - and -quartz. Combined the data of - quartz transition experiments with the results of calculation, the lattice parameters of - and -quartz at their transition pressure and temperature are determined firstly. Then, the strains, stresses and elastic energies for - quartz transformation were evaluated according to Hooke's law. The results indicate that at the pressure of 0~1.1 GPa, the linear strains vary in the range of -0.006~0.005, the volume strains in the range of -0.016~0.012, the stresses in the range of -0.46~0.14 GPa, and the elastic energies in the range of 965~2 760 kJ/m3. At about 0.5 GPa, the strains, stresses and elastic energies achieved their minimum values. Based on the calculation, the effect of the - quartz transformation on the wall rock in the crust during the acid magma intrusion is discussed.

Synthesis of Hydroxyapatite Powder by Shock Wave Treatment Method

LIAO Qi-Long, YANG Shi-Yuan, CAI Ling-Cang, ZHOU Da-Li, YIN Guang-Fu, ZHENG Chang-Qiong

2002, 16(4): 249-253 . doi: 10.11858/gywlxb.2002.04.002

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Abstract:
Hydroxyapatite (HA) is an effective materials used in bone prostheses. HA powders were prepared in the present paper by shock-loading the mixture of CaCO3 and CaHPO42H2O. The prepared HA powders were characterized by XRD, SEM, and FT2IR. It is shown that HA powders prepared by shock wave treatment are similar to those prepared by calcinations in structure and components, and contain CO32- ions. HA powders have smaller and uniform grain size, and much higher activity because of the existing of strain and dislocation defect s of crystals. It is believed that the method of shock wave treatment may be a new method for preparing HA powders used as a kind of biomaterials.

The Structure Properties of Ca2CuO3 under High Pressure

ZHANG Gong-Mu, MAI Wen-Jie, LI Feng-Ying, CHEN Liang-Chen, LIU Jing, YU Ri-Cheng, Lü Tian-Quan, JIN Chang-Qin

2002, 16(4): 254-258 . doi: 10.11858/gywlxb.2002.04.003

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Abstract:
In situ high-pressure energy dispersive X-ray diffraction measurements on polycrystalline powder Ca2CuO3 with Cu－O chain structure have been performed by using diamond anvil cell (DAC) instrument with synchrotron radiation. The results showed that the structure of Ca2CuO3 is stable under pressure up to 34 GPa. According to Birch-Murnaghan state equation, assuming B0=4, we got bulk modulus B0=165.41.8 GPa.

Preparation of GaN Ceramic under High Temperature and High Pressure

HONG Rui-Jin, MA Xian-Feng, YAN Xue-Wei, ZHAO Wei, TANG Hua-Guo

2002, 16(4): 259-264 . doi: 10.11858/gywlxb.2002.04.004

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Abstract:
GaN ceramics have been obtained under high temperature and high pressure. The use of a pressure of NH3 changed the situations of the decomposition of GaN during sintering, and the remainder of Ga2O3 in the materials impoved the crystallization of GaN as well. The relationship between the density ratio of sintered bodies and temperature has been studied by SEM and Archimedes method.

Preliminary Studies on Response of Longitudinal and Lateral Gauges for Shock Wave

DUAN Zhuo-Ping, GUAN Zhi-Yong

2002, 16(4): 265-270 . doi: 10.11858/gywlxb.2002.04.005

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Abstract:
In this paper, different dynamic response of the longitudinal and lateral gauges in PMMA and anti-shoot ceramic were investigated by 1-D plate flying tests and theoretical analyses. The experimental results indicate that the lateral stresses can be calculated directly from the piezoresistance expression calibrated by longitudinal stresses with the method of strain remedy by constantan gauge when the lateral stresses in anti-shoot ceramic are measured. But the lateral stresses in PMMA did not be determined by this method.

Long-Distance Flight Performances of Spherical Fragments

TAN Duo-Wang, WEN Dian-Ying, ZHANG Zhong-Bin, YU Chuan, XIE Pan-Hai

2002, 16(4): 271-275 . doi: 10.11858/gywlxb.2002.04.006

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Abstract:
Using two-stage light gas gun and laser technique for velocity easurement, we studied the long-distance flight performances of spherical fragments with different materials and different diameters. The flight distance is 60～120 m, and the initial velocity is 1.2～2.2 km/s. The experimental results show that: (1) the velocity attenuation coefficient of spherical fragment is constant, and (2) the air drag coefficient is slightly affected by the initial velocity of spherical fragment, the air drag coefficient is a linear function of initial velocity.

High Pressure Study on the Absorption Spectra of Lithium Doped in Solid H2

MA Yan-Ming, CUI Tian, HE Wen-Jiong, YIN Hong-Wei, ZOU Guang-Tian

2002, 16(4): 276-282 . doi: 10.11858/gywlxb.2002.04.007

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Abstract:
We employ quantum path-integral Monte Carlo method to investigate the pressure-induced absorption spectra of Li in solid H2 at T=5 K and pressure ranging from 0 to 2.4 GPa, based on Lax's semiclassical spectral line theory. The pressure-induced effects on Li atomic absorption spectra associate with an increase in half-width and a centroid spectral shift, which experiences a blue shift below a turning pressure (pt) and a red shift above pt under study. For lower symmetrical trapping site structures, application of pressure also results in a change in absorption line shape from a low symmetrical triplet feature to a doublet plus singlet pattern, in which the doublet to singlet splitting increases remarkably with the increasing of pressure.

Study on Emulsification Mechanism of Benzene and Water Mixture

Sun Yue, Yang Yan-Heng, Wu Guo-Dong, Yang Xiang-Dong

2002, 16(4): 283-290 . doi: 10.11858/gywlxb.2002.04.008

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Abstract:
With the final objective of developing shock-compression equation and phase-transition mechanism for mixed liquid material under extreme condition, such as high temperature and high pressure, several parameters, for instance, surface tension, stability and granularity distribution in benzene-water-emulsion three-body uniform mixture were measured at normal conditions. Experiments show that mixture liquid belongs to an unstable thermodynamic system. Surface tension is between that of benzene and water, and is not equal to their mean, which agrees with those references. The suitable circumstance temperature for preparation, storage and employing of the emulsified mixture is under 53 ℃. Moreover, the granularity distribution of the mixture liquid is narrowed after treatment by ult rasonic wave pulverizer, but it saverage diameter nearly unchanged. To solve the quantificational problem of liquid mixture in the initial state of the samples for detonation experiment, especially for multiple element solution which are difficult to dissolve reciprocally, the experiment results presented here provide some reliable data and the conclusions are valuable for preparing analogous experiment.

Phase Transformation on PZT-95/5 Ceramics with Low Density under Hydrostatic Pressure

ZHANG Yan-Yu, DU Jin-Mei, YUAN Wan-Zong

2002, 16(4): 291-296 . doi: 10.11858/gywlxb.2002.04.009

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Abstract:
The phase transformation of PZT-95/5 ceramics with low density under hydrostatic pressure were investigated experimentally. Experimental results show that ferroelectric to antiferroelectric phase transformation is closely related to pores in ceramics. Pore-collapse theory or Lateral-shear-stress hypothesis gives a qualitative illustration for the results. All the experimental results correspond to those given previously.

Pulsed Laser Deposition of Explosion Boron Nitride at Ambient Temperature

REN Zhi-Ang, ZHANG Can-Yun, ZHONG Xiang-Li, WANG Jin-Bin, YANG Guo-Wei

2002, 16(4): 297-300 . doi: 10.11858/gywlxb.2002.04.010

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Abstract:
In this study, explosion boron nitride (E-BN) was found in the process of depositing cubic boron nitride (cBN) thin film by Plasma Enhanced Pulsed Laser Deposition (PEPLD) method at room temperature. The E-BN thin film was identified using SEM, FTIR and X-ray diffraction techniques. The thermodynamic parameters and time parameter for preparing high-quality E-BN thin film were obtained. This has supported the existing formation theory of the structure of E-BN.

Reaction Mechanism of Na2B4O7 with NH4Cl in hBN Synthesis

ZHAO Hong-Mei, XU Xiao-Wei, LI Yu-Ping, WANG Bi-Yan

2002, 16(4): 301-304 . doi: 10.11858/gywlxb.2002.04.011

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Abstract:
The reaction mechanism in synthesis of hBN using Na2B4O7 and NH4Cl as the raw materials in the gas of NH3 under high-temperature and pressure was studied. The main function of NH4Cl in the reaction is to form a layer of membrane of high melting-point which can prevent Na2B4O7 particles from assembling. Meanwhile the NH3 gas provides much active molecules at high temperature to increase reaction ratio in the synthesis of hBN, and the newly formed hBN exists as separator stopping the appearance of glass phase.

Monte-Carlo Simulation for Thermal Resistance of Contact Surfaces

ZHONG Ming, CHENG Shu-Xia, SUN Cheng-Wei, HE Li-Qun

2002, 16(4): 305-308 . doi: 10.11858/gywlxb.2002.04.012

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Abstract:
Thermal resistance of contact interfaces of solids was simulated using Monte-Carlo method. Assuming that asperity heights obey Gauss distribution, the thermal resistance of contact surfaces was obtained by summarizing all the single point contact thermal resistances calculated. The results simulated using Monte-Carlo method are in better agreement with experimental data, relative to using normal integral method.

2002 Vol. 16, No. 4

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