高压物理学报

A Co-Relation of Dynamic Fragmental Fractal Dimension with the Loading

ZHANG Guan-Ren

1997, 11(2): 81-84 . doi: 10.11858/gywlxb.1997.02.001

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Abstract:
By using the generalized Mott formula deduced by Grady and Kipp, the formulae describing the fragment distribution under dynamic loading and the fractal dimension are obtained and presented in this paper. Furthermore, their connection with the loading and loading time is established. On the basis of these connections, the physical meaning of the fractal dimension of the fragments distribution is better understood than before.

A Study on Polyaniline FTIR and Its Resistance under High Pressure

XIAO Wan-Sheng, WENG Ke-Nan, PENG Wen-Shi, BAO Zhong-Xing, LIU Cui-Xia, ZENG Xing-Rong

1997, 11(2): 85-89 . doi: 10.11858/gywlxb.1997.02.002

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Abstract:
A Mao-Bell type of diamond anvil cell with Ⅱ-Type Diamond as anvil and infrared window has been used to study in situ Fourier transform infrared (FTIR) spectra of polyaniline under high pressures from 0 to 8.4 GPa. It shows that, between 4.8 and 5.2 GPa, areas of infrared absorption peaks standing for quinoid vibrations decrease compared to those caused by benzenoid vibrations, and this indicates that the structure of polyaniline has changed, and this kind of structural change is inconvertible. Resistance measurements of polyaniline under high pressures between 0 and 14.5 GPa show that resistance reduces dramatically with pressure increasing up to 7.5 GPa, at which a minimum of resistance-pressure curve occurs. These results suggest that polyaniline is a kind of electron conductive material, and its structural change leads to a minimum of resistance.

Shock Synthesis of Zinc Ferrite and Its Photocatalytic Activity in Dehydrogenation of H2S

LIU Jian-Jun, TAN Hua, XU Kang, HE Hong-Liang

1997, 11(2): 90-97 . doi: 10.11858/gywlxb.1997.02.003

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Abstract:
Zinc ferrite fine powders were synthesized from a very uniform mixture of nanometer zinc oxide and nanometer ferric oxide powders, by using shock compression techniques up to pressures 37 GPa, or by conventional high temperature calcination at 700 ℃ for 10 h. Both types of samples were used as a photo-catalyst in the dehydrogenation of H2S. Results show that shock synthesized zinc ferrite exhibits much higher photo catalytic activity and is a factor of 3 larger than that of the calcinated, which increase with the shock pressures under which the catalyst was synthesized. In contrast, photo catalytic activity of single component catalyst of ZnO and Fe2O3 decreases as the shock conditioning pressure increases. Characteristics of the XRD patterns of shock synthesized zinc ferrite along with its TEM features and Mossbauer spectra indicate that the enhancement in catalytic activity of photo-dehydrogenation may be attributed to the formation of the very fine and highly non-stoichiometric zinc ferrite during shock synthesis processing.

A Theoretical Calculation for the Hugoniots and Temperatures of Water Using the Exponential-Six Reference Potential

YANG Xiang-Dong, WU Bao-Jian, HU Dong, JING Fu-Qian

1997, 11(2): 98-102 . doi: 10.11858/gywlxb.1997.02.004

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Abstract:
With the exponential six reference potential, the shock Hugoniots and temperatures of water are calculated by using Ree's improved WCA theory and Ross' variational fluid perturbation theory. Our calculation results agree well with the experimental data.

Multi-Stage Air-Gap Fiber Optic Probe

FANG Qing, TAN Xian-Xiang

1997, 11(2): 103-109 . doi: 10.11858/gywlxb.1997.02.005

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Abstract:
Multi-stage air-gap fiber optic probe (MAFOP) is used to measure detonation velocity for solid and liquid explosives. The MAFOP is made of plastic fiber with 0.8 mm in diameter, 10 meters in length and 0.25 in numerical aperture. There are four holes drilled on the input end of the fiber which are used as the air-gaps of the probe. The diameter of the holes is 0.25 mm and the distance between holes can be changed as needed. When the air-gaps of the MAFOP are inserted into the solid or liquid explosives and detonation wave propagates and reaches the probe, the air-gaps will light intensively. The output ends of the fibers are put on the slit of image converter streak camera. A transient analyzer consisted of photocamera and micro-processor stores and processes the image data on the image tube phosphor screen. The measured results used MAFOP for TNT/RDX (40/60, =1.70 g/cm3) and nitromethane are presented in the paper. The results also show that the MAFOP is very useful in studying of explosive detonation when combined with image converter camera.

Using Mach Reflection Effect in Synthesis of Ultrafine Diamond by Detonation Wave Method

ZHAO Sheng, YUN Shou-Rong, CHEN Quan, MA Feng, CHEN Peng-Wan

1997, 11(2): 110-116 . doi: 10.11858/gywlxb.1997.02.006

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Abstract:
This paper proposes a method to use Mach effect in explosive detonation to enhance the yield of ultrafine diamond. The detonation parameters on Mach rod were computed by Whitham method. The cylindrical charge in experiment was TNT wrapped with TNT/RDX (30/70) charges. Ultrafine diamond can be obtained from the soot of detonation product in a nitrogen-filled chamber, the yield is 6%; if this charge is wrapped with salt, the yield can be more than 10%.

Critical Curves of Binary Systems Vapor-Liquid

TIAN Yi-Ling, SONG Ying, REN Xiao-Wen, ZHANG Feng-Cai

1997, 11(2): 117-123 . doi: 10.11858/gywlxb.1997.02.007

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Abstract:
Six basic types of gas-liquid critical curves for binary systems have been analyzed and described. By the equation of state obtained from hard-ball model which is suitable for high temperature and high pressure, critical curves of four systems are calculated. In calculations, there are only three adjustable parameters for each system. The calculated results are identical with the experimental values.

A Kind of Low Temperature Target System and Its Application in Shock Compression Studying of Liquid

SUN Yue, CHEN Xian-Meng, CHEN Pan-Sen, LIU Fu-Sheng, ZHOU Xue-Fen, ZHANG Qing-Fu

1997, 11(2): 124-129 . doi: 10.11858/gywlxb.1997.02.008

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Abstract:
This paper presents a kind of low temperature target system (temperature between 180～290 K) for the two-stage light gas gun and the technique for preparing molecular liquid samples of high purity at low temperatures. This technique was successfully used in preparing liquid CO2 samples. The shock compression results show that these samples totally meet the needs of shock wave experiments. We obtained seven shock-compression data points between 20～60 GPa. The results indicate that shock compressions induced a phase transition of liquid CO2 at 30 GPa.

A Study on High Velocity Impact of Spherical Projectile against Steel and Aluminium Target Plates and the Scaling Relation

WEN Dian-Ying

1997, 11(2): 130-136 . doi: 10.11858/gywlxb.1997.02.009

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Abstract:
The data of cratering in the penetration of high velocity impact of tungsten, steel, zirconium and titanium ball projectiles against steel and aluminium target plates are given; the corresponding scaling relations are discussed.

Diamond Synthesis from a System of Silicon-Carbide and Iron

JIANG Jin-Chun, LI Liang-Bin, HONG Shi-Ming, ZHONG Yu-Mao, ZHANG Xin-Yuan, WEI Jian-Jun

1997, 11(2): 137-141 . doi: 10.11858/gywlxb.1997.02.010

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Abstract:
In order to ascertain the mechanism of the effect of catalysts on the process of diamond formation from SiC, it is necessary to investigate the behaviour of the SiC admixed with different metallic catalysts under high pressure and high temperature. In this work, SiC and iron powders were mixed in weight ratio of 1∶6, and then treated at high pressure of 5.4～6.0 GPa and temperature of 1 300～1 500 ℃ for 20 min. X-ray diffraction of the samples showed that SiC decomposed, and Fe3C and Fe3Si formed respectively in the all experiments. The decomposition of SiC carried more thoroughly under higher temperature. Diamond and graphite prectipitated clearly above 1 375 ℃ with the decrease of Fe3C. Observation in a scanning electron microscope showed that diamond crystals obtained at 6.0 GPa and 1 500 ℃ have perfect octahedron shape, the average grain size is about 50 m.

A Study on the Pressure-Resistance of Coliform Group in Raw Milk

CHI Yuan-Bin, MA Xiao-Fan, LIU Bo, CUI Qi-Liang, JIN Zeng-Sun, LUO Wei

1997, 11(2): 142-144 . doi: 10.11858/gywlxb.1997.02.011

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Abstract:
In order to investigate the pressure-resistance of the coliforms, the milk samples inoculated with coliforms were treated at 20 ℃ and the pressures ranging from 0.1 to 430 MPa for 5 or 15 min. Results show that the most coliforms can survive at 40MPa.More than 70% of the coliforms, however, were killed under pressure of 100 MPa for 5 min. A few of pressure-proof coliforms still survived at pressures up to 430 MPa.

Experimental Studies of Alumina Ceramic against a Shaped-Charge Jet Penetration

TAN Duo-Wang, XIE Pan-Hai

1997, 11(2): 145-149 . doi: 10.11858/gywlxb.1997.02.012

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Abstract:
The interaction between an alumina ceramic target and a shaped-charge jet is observed by means of flash X-ray photography. The results show that the crater collapse occurs during jet penetration, which results in the disalignment and break-up of the jet and hence lower down its penetration capacity.

Effect and Mechanism of the Solution Carbon in Ni-Mn Powder Catalyst

YI Jian-Hong, MA Fu-Kang, Lü Hai-Bo

1997, 11(2): 150-155 . doi: 10.11858/gywlxb.1997.02.013

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Abstract:
Effects of solution carbon in Ni-Mn powder catalyst on diamond synthesis were investigated by using a cubic press. The behavior of the solution carbon in the synthesizing process was examined. Experiment results show that the solution carbon in the powder catalyst can increase not only the yields of diamond, enhance the synthesis efficiency, but also the nucleation rate, promoting the formation of better shape (perfect) crystals. A discussion of the mechanism of the effects of the solution carbon in the catalyst powder was presented.

The Projectile Impacting Velocity Measurement Technique with Splitting Laser Beams

ZHANG Guang-Jun, TIAN Chang-Jin, HE Peng

1997, 11(2): 156-160 . doi: 10.11858/gywlxb.1997.02.014

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Abstract:
We designed and developed an element, which can split a single laser beam produced by a He-Ne laser device of 4 mV power into ten paralleled laser beams with an equal space-distance of 5 mm between each beam pair. We have developed a photo-electric transformer, which is of high sensitivity, waveform synthesized and has a single output channel. When combined with the digital oscilloscope and personal computer, we have the system can be used to measure the impacting velocity of the projectile launched by a gas gun.

1997 Vol. 11, No. 2

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