高压物理学报

Shock Wave and Condensation of Fractal Clusters

ZHANG Guan-Ren

1997, 11(4): 241-244 . doi: 10.11858/gywlxb.1997.04.001

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Abstract:
The properties of the fractal cluster and the effects of shock wave are described in this paper. The author also analyzed the condensation speed of the fractal clusters in fluids or gases after shocking. The conclusion is that shock wave can speed up condensation. Finally, illustrations for the treatments of contaminated water by shock waves are presented and the problems of the present method are pointed out by the author.

The Effect of High Pressure on the Defect Structure in the Nanocomposite Oxide Materials

SUI Yu, ZHENG Fan-Lei, XU Da-Peng, SU Wen-Hui, GUO Ying-Huan, YANG Hua, WANG Yun-Yu

1997, 11(4): 245-249 . doi: 10.11858/gywlxb.1997.04.002

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Abstract:
In this paper, the positron annihilation lifetime spectra of NiFe2O4 nanocrystalline materials compacted under different pressures (0～4.5 GPa) were measured. The variations of the defect structure of NiFe2O4 nanocrystalline with compacting pressure were analyzed and compared with those of La0.7Sr0.3MnO3 nanosolids with different microstructural characteristics. The size of the interface free volume and the microvoid in NiFe2O4 nanocrystalline were all compressed measurably under high pressure, but the former has higher compressibility. These changes mean that the arrangement degree of order of the interface atoms of NiFe2O4 nanocrystalline is enhanced gradually with the increasing of compacting pressure.

Theoretical Studies of EOS and Phase Transitions of Carbon under High Pressure and High Temperature

YANG Xiang-Dong, ZHANG Hong, HU Dong, JING Fu-Qian

1997, 11(4): 250-253 . doi: 10.11858/gywlxb.1997.04.003

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Abstract:
Equation of state (EOS) of three-phase carbon (graphite, diamond, and liquid), including solid-solid phase transition from graphite to diamond under high pressure and melting line of graphite and diamond under high temperature has been studied. The melting-curve of diamond we obtained has a positive slope, and the graphite-diamond-liquid triple point is about 4 400 K, 14 GPa.

Determination of the Yield Strength of 93W Alloys by Using AC Techniques

ZHANG Jiang-Yue, TAN Hua, YU Ji-Lin

1997, 11(4): 254-259 . doi: 10.11858/gywlxb.1997.04.004

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Abstract:
Contrary to the ordinary plate impact experiments which only gives the uniaxial response of the material under shock loading, this study uses the general plate impact technique but a new data processing method, and give us some information about the strength of the material being impacted. Multiple flyer impact technique is used in this experiment in order to generate the loading-reloading or loading-unloading process in a tungsten alloy (93W). VISAR (Velocity Interferometer System for Any Reflector) technique is used to get the particle velocity-time profile at the sample/window interface. From the shock-reshock or shock release particle velocity-time profile obtained from the experiments, and using a self-consistence data processing technique developed in the research, we obtained the strength of the tungsten alloy at 11 GPa, 32 GPa and 96 GPa, which is 1.8 GPa, 2.6 GPa and 4.9 GPa respectively. Based on which we find that although the yield strength of 93W increases as the shock pressure increases, but the ratio of the yield strength to the shock pressure decreases.

A Thermodynamic Study on the Crystallization Processes of Amorphous (Fe0.99,Mo0.01)78Si9B13 Alloy under High Pressrue

LIN Xiao-Min, YAO Bin, SU Wen-Hui

1997, 11(4): 260-265 . doi: 10.11858/gywlxb.1997.04.005

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Abstract:
Amorphous (Fe0.99,Mo0.01)78Si9B13 alloys were annealed for 30 min at a temperature between 600 K and 930 K under pressures of normal pressure to 7 GPa. It was found that precipitation temperature of their crystallization products of -Fe(Mo,Si), Fe3B and Fe2B alloys are related closely to the pressure used. Crystallization temperature of amorphous alloy and precipitation temperature of the metastable phase Fe3B decrease with increasing pressure at the present pressure condition. At certain temperature and pressure, the Fe3B alloy will transform into a stable phase Fe2B and its transition temperature changes with pressure. A thermodynamic mechanism on the crystallization of the amorphous (Fe0.99,Mo0.01)78Si9B13 alloy and the phase transition of the Fe3B to the Fe2B was discussed, and an equation of the phase transition from the Fe3B to the Fe2B was given.

A Study on the Diamond Synthesis by B4C under High Temperature and High Pressure

LUO Xiang-Jie, DING Li-Ye, LIU Qiang, YE Li, LUO Bo-Cheng

1997, 11(4): 266-269 . doi: 10.11858/gywlxb.1997.04.006

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Abstract:
Diamond was synthesized by using B4C as the carbon source in the Ni70Mn25Co5-B4C system under 5.7～6.0 GPa and 1 370～1 500 ℃.This is the first example using pure B4C as the carbon source to synthesize diamonds, which is dark and contains more than 1wt% of boron. The synthesized diamond has a grain-size of about 20 m, is mainly a combination of cubic and octahedral bodies. After reaction, Ni2B compounds are found to exist in the metallic catalyst left, and B13C2 compounds with rich boron in the non-metallic remainders.

Explosive Logic Element－Asynchronous and Logic Gate

JIANG De-Chun, ZENG Fan-Qun, TAN Duo-Wang, YANG Bin

1997, 11(4): 270-275 . doi: 10.11858/gywlxb.1997.04.007

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Abstract:
With four explosive NULL gate, an asynchronous explosive AND gate is designed. Compared with synchronous explosive AND gate, it requires no synchrony and time sequencing to its two inputs, thus extends its application area and improves its reliability of normal function. Probability window of safty/reliability for the parameters of the explosive NULL gate is given and the time sequencing relationship of the asynchronous AND gate is also discussed.

A Glassy Al-Fe Based Alloy Formed by Solid State Reaction between Al and Amorphous Fe-Mo-Si-B Alloy under High Pressure

LI Fu-Shan, SUN Qi-Mei, YAO Bin, SU Wen-Hui

1997, 11(4): 276-282 . doi: 10.11858/gywlxb.1997.04.008

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Abstract:
A solid state reaction between Al and amorphous (Fe0.99, Mo0.01)78Si9B13 alloy was investigated under 4 GPa, at temperatures ranging from 780 K to 900 K. The microstructures of the diffusion bands formed by the reaction on the interfaces of Al and the amorphous (Fe0.99, Mo0.01)78Si9B13 alloy were studied by use of transmission electron microscope, X-ray diffractometer and scanning electron microscope. And a glassy Al-Fe based alloy was observed in the diffusion bands produced at temperature of 780 K to 840 K. Its crystallization temperature is estimated to be about 870 K. The formation mechanisms of the Al-Fe based glass are discussed.

Fluid Dynamic Numerical Simulation of an Explosive-Gas-Compression Generator

HONG Yan-Ji, XUE Hong-Lu

1997, 11(4): 283-291 . doi: 10.11858/gywlxb.1997.04.009

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Abstract:
In this paper, the Fluid in Cell method is used to numerically simulate two-dimensional, axisymmetric and time-dependent motion for the compressible flow of a fluid which was in the sharp angle regions between the fly-plate and the wall of the compression-chamber. Compression properties of the fluid in the gas compression chamber, and motion properties of the high-temperature plasma in the outlet-tube, were studied and discussed. The distributions of plasmas variables were obtained, which were comprised with reported experimental data.

Solid State Reaction in Nanocrystalline Ti60Si40 Mixture under High Pressure

ZHANG Fu-Xiang, YU Wen, HE Duan-Wei, WANG Wen-Kui

1997, 11(4): 292-295 . doi: 10.11858/gywlxb.1997.04.010

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Abstract:
Nanocrystalline mixture of Ti60Si40 was prepared by ball milling and the solid state reactions between Ti and Si have been studied under different pressures. The phase composition of the samples were identified by X-ray diffraction and electromicrocopy. The results indicated that the amount of a new phase formed during milling grown up at certain pressure and temperature, while its growth rate decreases with increasing pressure. No reactions occur and only the growth of nanocrystals in the same sample when treated under the same conditions at normal pressure.

Experimental Study on the Laser Thermal Stress of Aluminum Target

ZHANG Ke-Xing, LIU Xu-Fa, LIU Cang-Li, SUN Cheng-Wei, ZHANG Ning

1997, 11(4): 296-302 . doi: 10.11858/gywlxb.1997.04.011

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Abstract:
The laser thermal stress induced in the aluminum alloy plate irradiated by CW/COIL was investigated by high temperature straingauge and thermocouple gauge and other diagnostic techniques in this paper. When the laser intensity irradiated on the target surface is about 1 000 W/cm2, the laser thermal stress descends rapidly with the increase of target thickness; for the target thickness h=1.00 mm irradiated by laser beams, and the laser intensity I=640～980 W/cm2, the laser thermal stress increases with the increase of laser intensity irradiated on the target surface. Both types of the laser thermal stress-time curves become complicated with the decrease of the target thickness or with the increase of laser intensity irradiated on the target surface. When target thickness h2.50 mm and laser intensity I800 W/cm2, the laser thermal stress strength is greater than the material fracture strength in the laser irradiation zone, holes and fracture strips occur and materials damage.

A Study of the Heat Resistance of N+ Implanted Synthetic Diamond

LI Peng-Yuan, GENG Man, TIE Jun, HUANG Pei-Ji, CUI Xi-Rong, YAN Bing, WANG Jing-Quan, JIANG Yuan-Qi

1997, 11(4): 303-306 . doi: 10.11858/gywlxb.1997.04.012

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Abstract:
Synthetic diamond crystals implanted with 20～70 keV N+ have been investigated. The heat resistance of the implanted synthetic diamond crystals was measured by DTA. It shows that its heat resistance increased with the ion doses, though this enhancement slows down as the ion energy increases, it also shows that transformation of the ion implanted diamond into graphite under high temperature condition was greatly improved.

1997 Vol. 11, No. 4

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