高压物理学报

The Sensitivity of Manganin Stress Gauge

ZHANG Guan-Ren

1988, 2(3): 193-201 . doi: 10.11858/gywlxb.1988.03.001

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Abstract:
According to the theory of the resistivity of manganin alloy given by K. Yosida, the resistivity is proportional to the following quantities: VDS/Ef, where Ef is the Fermi energy of an electron, V is the volume of the conductor, S is the spin of the manganese ion, D is the exchange integral function. Substituting into the formula of resistance, it is given R/R=D/D－Ef/Ef+S/S+2V/(3V). Then the autor derives the relations of the former three terms in the right hand of this equation to V/V, and by means of the hydrostatic compression curve, gets the relation of R/R with respect to as following R/R0=2.41105p (Pa), the relation with the dynamical pressure is R/R0=2.8105p (Pa). The results are compared with the experimental works both abroad and at home, they are very in accord with each other.

Calculations of Diamagnetic Susceptibilities for Noble Gas Atoms with the Modified Thomas-Fermi Models (Ⅰ)

FENG Xiao-Dong

1988, 2(3): 202-210 . doi: 10.11858/gywlxb.1988.03.002

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Abstract:
The diamagnetic susceptibilities of noble gas atoms: Ne, Ar, Kr, Xe, Rn are calculated in this paper with the Thomas-Fermi (TF), Thomas-Fermi-Amadi (TFA), TFAD and SICTFD models. The Jensen's trial density function is used and the asymptotic behavior of density determined by the TF model and its modified version is taken into account. The calculated results are better than those given by Jensen, Csavinzky and Donnamaria et al.

An Isothermal Equation of State for Solid (Ⅴ)－Equation of state at High Temperature

XU Ji-An

1988, 2(3): 211-217 . doi: 10.11858/gywlxb.1988.03.003

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Abstract:
In present work, using NaCl as an example, we proved that the equations of state of solid (EOS) at various temperatures can be considered in our px pressure coordinate as one EOS, in which they start at different points. Then the EOS of any material at high temperature can be estimated from the data of its EOS at room temperature and thermal expansion at atmosphere.

Experimental Studies on the Attenuation of Shock Waves in LY12-M Aluminum

TANG Wen-Hui, ZHANG Ruo-Qi, CHEN Xue-Fang

1988, 2(3): 218-226 . doi: 10.11858/gywlxb.1988.03.004

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Abstract:
The attenuation of planar shock waves in LY12-M aluminum was measured with the manganin piezoresistive gages. The peak pressure of shock waves initially is 4.92 GPa. Both the positron lifetimes and the vickers microhardness were measured. The influences of dislocations and other crystal defects on the nonhydrodynamic attenuation of shock waves as well as the shock hardening effect in LY12-M aluminum are discussed.

The Equation of State for Gun Propellant Gases under High Pressure

CHAO Gui-Tong, YU Yu-Hua, WU Shan-Nan, QU Yong-De

1988, 2(3): 227-236 . doi: 10.11858/gywlxb.1988.03.005

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Abstract:
Based on the kinetic theory of molecules and in consideration of high density molecular collision and molecular interaction at high temperature, we propose a simplified model of three molecular collision and introduce the shielding effect of the molecule. In this way, an equation of state of polynomial type is set up that describes the real performance of gun propellant gas under high pressure. We calculated the pressure up to 800 MPa for the gun propellants with different composition. The calculated pressure is in excellent agreement with the experimental data and is better than those calculated by the BLAKE code and used by the US Army.

The Luminescence Characters of High-Pressure Synthesized Europium (2)－Activated Strontium of Borate

XU Wei, SU Wen-Hui, CUI Shuo-Jing, WU Dai-Ming

1988, 2(3): 237-247 . doi: 10.11858/gywlxb.1988.03.006

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Abstract:
Sr3B2O6:Eu2+, Sr2B2O5:Eu2+ and SrB4O7:Eu2+ were synthesized by the high-pressure method for the first time, and luminescence measurements of them and SrB2O4:Eu2+ were carried out. The luminescence characters were compared with those under atmosphere. The structures and emission bands of Sr3B2O6:Eu2+ and Sr2B2O5:Eu2+ have been changed due to the high pressure processing. Under an appropriate pressure (2.8 GPa) the emission intensity of SrB2O4:Eu2+ drastically increased. Its quantum efficency at the optinium excitation 313 nm is above 80 times higher than the previous one.

Calculations of the Energy and Polarizability for the H-Like Atom under High Pressures

GOU Bing-Cong, GOU Qing-Quan

1988, 2(3): 248-253 . doi: 10.11858/gywlxb.1988.03.007

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Abstract:
The hydrogen-like atom, enclosed in a spherical box of radius r0, has been used as the model of the compressed hydrogen-like atom. The boundary condition that the wave function (r) must be zero as r approaches to infinite is replaced by the condition that (r) have a zero point at a finite r=r0. From the wave function for this model, the energy and polarizability are calculated as the functions of r0 and the corresponding pressure.

Comperssibilities and Pressure-Induced Crystallization Phenomena of Metallic Glasses Cu100-xZrx

WANG Li-Jun, HAN Shun-Hui

1988, 2(3): 254-258 . doi: 10.11858/gywlxb.1988.03.008

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Abstract:
The determination of the compressibilities of metallic glasses Cu100-xZrx in a diamond anvil cell by the X-ray diffraction technique is described in this paper. The line compressibilities determined for Cu30Zr70 and Cu25Zr75 are 2.710-3 GPa-1 and 2.310-3 GPa-1 respectively. The highest experimental pressure is over 30 GPa. The pressure-induced crystallization of metallic glasses Cu100-xZrx at room temperature was firstly observed in this experiment.

A Measurement of the Curie Temperature in Ferromagnetic Materials

YIN Xiu-Jun, SHEN Zhong-Yi, ZHANG Yun, HONG Jing-Xin

1988, 2(3): 259-263 . doi: 10.11858/gywlxb.1988.03.009

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Abstract:
A measurement of the Curie temperature for the ferromagnetic meterial pressed by the piston in a cylindric pressure vessel. The system has higher sensitivity so that the small samples could be measured, though it consists only of simple measuring circuits and without precise instruments such as the phase lock amplifier. The measurement turns out a success due to the reasonable configuration for getting high pressure. The measurement data show that the repetability error is less than 1 ℃.

The Catalytic Materials Used in Synthesis of Cubic Boron Nitride under High Pressure

MA Xian-Feng, YAN Xue-Wei, NI Jia-Zuan, CUI Shuo-Jing, SU Wen-Hui, QIAN Zheng-Nan, WANG Yi-Feng

1988, 2(3): 264-269 . doi: 10.11858/gywlxb.1988.03.010

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Abstract:
The preparation of catalytic materials Mg3B2N4 and Ca3B2N4 used in synthesis of cubic boron nitride under high pressure and their stability and catalysis are discussed in this paper. The crystalline of the hBN and the synthesis temperature time process and circumstance have important influence on the quality and stability of the catalysts. With these catalysis, the cBN was synthesized under high pressure and high temperature. These catalysts are characterized as lower synthesis pressure, higher transformation radio, wider range of synthesis pressure and temperature, lower impurity content and higher strength.

Image Processing for Flash X-Ray Cineradiography in Detonation Experiments

LI Chun-Mei

1988, 2(3): 270-276 . doi: 10.11858/gywlxb.1988.03.011

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Abstract:
A digital technique of image processing using a microcomputer for flash X-ray cineradiography in detonation experiments system is described in this paper. A set of flash X-ray films were treated with this technique and the transformed images have been improved.

An Instantaneous Optical Pyrometer with Six Channels for the Shock Temperature Measurement in Materials

WANG Gui-Chao, YU Quan-You, Lü Xiu-Sheng, WANG Da-Quan

1988, 2(3): 277-284 . doi: 10.11858/gywlxb.1988.03.012

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Abstract:
An instantaneous optical pyrometer to measure the spectral radiance of the materials shoched to high pressures has been developed. Thermal radiation emitted by the source is sampled at six wavelength bands from visible to near infrared spectrum, and the signal for each channel is separately transited though the optical fiber and then detected by photomultipliers and oscilloscopes with a time resolution of 20 ns. Shock temperatures ranging from 2 400 K to 9 000 K could been reliably measured with an error less than 3%. The results of some experiments on air and NaI crystals are also given.

A Study on the Relation between Dielectric Characteristics and Mechanical Strength of Synthetic Diamond

CHEN Shu-Xin

1988, 2(3): 285-287 . doi: 10.11858/gywlxb.1988.03.013

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Abstract:
The dielectric characteristics of synthetic diamond are related to its structural defects and mechanical strength. Experiments performed in this work showed that for the diamond being used as medium of a capacitor the more complete the crystal form is, the less increase of the capacitance is.

1988 Vol. 2, No. 3

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