高压物理学报

Synthesis of SiCp/Al Nanocomposite under Ultra-High Pressure

LIU Hao-Zhe, HE Hong-Liang, WANG Lu-Hong, WANG Ai-Min, JIN Chang-Qing

1999, 13(1): 1-6 . doi: 10.11858/gywlxb.1999.01.001

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Abstract:
SiC nanoparticle reinforced Al-matrix composite has been synthesized under the ultra-high pressure. X-ray diffraction (XRD), high resolution electron microscopy (HREM), positron annihilation and Vickers micro-hardness measurements have been used to evaluate the chemical reaction and the bonding behavior between the reinforced phase and the matrix. Results demonstrate that ultra high pressure can effectively depress the boundary reaction, enhance the condensed density and modify the boundary bonding conditions.

Experimental Investigation on the Errors of the in Situ Magnetic Measurements in Hydrostatic High Pressure Vessel (3)－Comprehensive Consideration of Two Influences

SU Fang, SU Xiao

1999, 13(1): 7-14 . doi: 10.11858/gywlxb.1999.01.002

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Abstract:
In order to investigate the errors of the primary coil with multiple electric solenoid, we selected two samples using different slice-number (n=1, 3) of amorphous alloy Fe46.3Co0.03Ni46.5Si3.75V0.92B2.5 ribbon, inserted into the 13 layers electric solenoid and measured the magnetization, magnetic permeability curve and initial magnetization curves, separately, in the hydrostatic pressure vessel and under other four different ambient conditions. (1) We find that there exist both a demagnetic field H' of the magnetized sample and a demagnetic field H'' of the neighbor iron magnetized by leakage flux. (2) To reduce the influence of H', we take one slice of amorphous alloy ribbon as the sample, but the influence of H'' becomes serious as the errors of m and i increase to m/m=50%, i/i＝104%. (3) Comprehensively taking into account these two influences, we take three slices of amorphous alloy ribbon as the sample, although the influence of H' increases a little, the influence of H'' is weakened significantly, so the errors of m and i decrease to m/m=29%, i/i＝15.5%.

Experimental Studies of Blowoff Impulse Induced by Electron Beam with Different Materials and Different Energy Fluxes

PENG Chang-Xian, TAN Hong-Mei, HU Ze-Gen, LIN Peng, LIU Jin

1999, 13(1): 15-21 . doi: 10.11858/gywlxb.1999.01.003

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Abstract:
In this paper, the experimental studies of variation of blowoff impulse with different materials and different energy fluxes are described. The experiments are conducted on FLASH-Ⅱ electron beam equipment with the probe principle of directly measuring the specific series of time intervals and miniature transduction technique passing infrared ray. The experimental results show that the coupling coefficients of blowoff impulse for two specific materials only is 1/3 and 1/2 or so of those of LY-12 aluminum alloy, respectively, in about the same energy fluxes. This shows that the two specific materials when they are radiated possess good property which can reduce blowoff impulses.

Changes of Solubility and Rheological Property of the Isolated Soybean Protein after High Pressure Treatment and Its Mechanism

LI Bian-Sheng, ZENG Qing-Xiao, PENG Zhi-Ying, CHEN Bo-Nuan, LIANG Di-Hua

1999, 13(1): 22-29 . doi: 10.11858/gywlxb.1999.01.004

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Abstract:
The changes as well as its mechanism of solubility and rheological property of the isolated soybean protein (ISP) in water solution after high pressure treatment were studied. The solubility of ISP was improved after high pressure treatment, which had the highest increment after pressurization at 400 MPa for 15 min, for the low concentration (4.0%～6.6%) of protein solution. The apparent viscosity of the ISP solution also increased after high pressure treatment. The storage modulus G' and the loss modulus G'' were increased as the treating pressure increasing. Results of the scanning electron microscope and polyacrylamide gel electrophoresis showed that the molecular of ISP in solution had some depolymerization and unfolding after the treatment at high pressures below 400 MPa. Meanwhile, the particles of the protein decreased and the fraction of protein particles in total volume increased. The infrared spectrum analysis of the pressurized ISP solution showed an increase of charge distribution of protein. It is suggested that the changes of physical and chemical properties of the pressurized ISP solution are due to the structural changes of ISP molecule.

Phase Transitions and Electronic Properties of La1.65Sr0.35CaCu2O4+Cly under High Pressure

BAO Zhong-Xing, XU Li-Wen, CHE Guang-Can, LIU Cui-Xia, CHEN Hong, WU Fei, ZHAO Zhong-Xian

1999, 13(1): 30-33 . doi: 10.11858/gywlxb.1999.01.005

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Abstract:
The pressure-induced phase transitions, including some irreversible transitions from crystallite to noncrystallite, of copper oxy-chloride superconductor La1.65Sr0.35CaCu2O4+Cly were studied by both the measurements of electronic resistance (R) dependence on pressure (p) and X-ray diffraction techniques. The R-p experiments were performed in the diamond anvil cell by resistance measurement technique at room temperature under pressures up to 22 GPa. The interesting results were obtained and are presented first in this paper.

Pressure-Induced Structural Phase Transition of Ba3Bi3Ti4NbO18

HAN Jie, ZOU Guang-Tian, CUI Tian

1999, 13(1): 34-36 . doi: 10.11858/gywlxb.1999.01.006

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Abstract:
The pressure-induced structural phase transition of the layered ferroelectrics Ba3Bi3Ti4NbO18 and its variation of Raman spectra under 8.87 GPa have been studied. The internal modes of Ba3Bi3Ti4NbO18 have been assigned according to the internal mode approach. It was found that Ba3Bi3Ti4NbO18 experienced a structural phase transition at 4.54 GPa.

Volume Adding Model and Thermodynamic Self-Consistency for Equation of State of Mixtures

WANG Zheng-Yan, LI Mao-Sheng, CHEN Dong-Quan, XU Xi-Shen

1999, 13(1): 37-41 . doi: 10.11858/gywlxb.1999.01.007

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Abstract:
In this article we present a volume-adding model to calculate EOS of mixture numerically using tabulated EOS data for its constituents with volume-pressure iterative method. Meanwhile, it is proved that if each of the constituent EOS satisfies the thermodynamic self-consistency, their mixture EOS will do also. Finally EOS of atmosphere and of Xe-D2 are calculated as the examples.

The Determination of Lagrangian Sound Velocities for 93W Alloy under Shock Loading and Its Application

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

1999, 13(1): 42-49 . doi: 10.11858/gywlxb.1999.01.008

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Abstract:
It is believed that material always has a finite strength before reaching its shock melting point. In other words, shear strength will not equal to zero at the initial shock compression states before shock melting occurs. In the classical shock pressure experimental measurements, however, we often take it for granted that the normal stress along the direction of shock wave propagation equals the mean stress, or the pressure. This will introduce definitely some uncertainty in the fine equation of state construction. In this paper, we measured the shock loading-reloading and unloading particle velocity history of 93W alloy at the sample/window (Al2O3) interface by using a time resolved velocity measurement technique (VISAR). The longitudinal and bulk Lagrangian sound velocities were deduced from the measured particle velocity history. From the relation of sound velocity vs the strain, we obtained the initial shear stress 0 (ranged from 0.11 to 2.02 GPa), critical shear stress c (ranged from 0.63 to 2.40 GPa), shear modulus G, at three initial shock pressure points of 16, 32 and 95 GPa. And a revised shock Hugoniot curve of 93W alloy taking into account of its material strength effects at shock pressures up to 100 GPa is also presented.

Research on the High Transformation Ratio of Graphite to Diamond by the Static Pressure Method

YI Jian-Hong

1999, 13(1): 50-54 . doi: 10.11858/gywlxb.1999.01.009

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Abstract:
Catalystic materials play an important role in the diamond synthesis. It can reduce the pressure and temperature required to transform graphite into diamond. By using Ni-Mn-C powder catalyst, the diamond synthesis with a transformation ratio of 90% from graphite has been achieved in this paper.

Review and Look Forward to the Progress of VLW Equation of State

WU Xiong, LONG Xin-Ping, HE Bi, JIANG Xiao-Hua

1999, 13(1): 55-58 . doi: 10.11858/gywlxb.1999.01.010

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Abstract:
The background of the establishment of VLW equation of state (EOS) has been reviewed in this paper. Comments on the fact that the third item of VLW EOS has been proved theoretically after VLW EOS proposed about ten years was made. The future progress of it is forecasted.

Raman Scattering of Ultrafine Diamond Obtained from Detonation

CHEN Peng-Wan, YUN Shou-Rong, HUANG Feng-Lei, CHEN Quan, MA Feng

1999, 13(1): 59-63 . doi: 10.11858/gywlxb.1999.01.011

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Abstract:
Raman spectra of ultrafine diamond obtained from detonation are measured. The characteristic Raman bands assigned to sp3 diamond and sp2 graphite have been observed at around 1 321 cm-1 and 1 600 cm-1, respectively, in which the sp3 diamond band is asymmetric with the half-peak width of about 30 cm-1, with a tail towards lower Raman frequency and a shift of about -10 cm-1. The results obtained from Raman spectrum agree with that from X-ray diffraction.

Investigation on Impact Sensitivity of Explosive with Fractal Geometry

LIN Qi-Wen, XIA Xian-Gui, YANG Guang-Zhi, ZHANG Guan-Ren, LIAO Han-Ning

1999, 13(1): 64-70 . doi: 10.11858/gywlxb.1999.01.012

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Abstract:
The framing photographs of explosive samples under drop hammer test exhibit a fractal structure, in which the fractal dimension is related to the explosive's impact sensitivity. Based on the perimeter-area relation in fractal geometry and the linear recurrent analysis, fractal dimension calculations have been done for six kinds of explosive samples (e.g. TATB). We find that the fractal dimensions of the inert explosives are greater than that of the others. Besides, the sequential orders of the fractal dimension for the six kinds of explosives are in agreement with that of the drop hammer height. Therefore, we consider that it is possible and feasible to characterize the impact sensitivity of explosive with its fractal dimension.

Diffuse Reflectivity of Shock-Compressed Tungsten Target to 514.5 nm Laser

LI Ze-Ren, LIU Jun, CHENG Xiao-Feng, MA Ru-Chao, YAO Jian-Quan

1999, 13(1): 71-75 . doi: 10.11858/gywlxb.1999.01.013

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Abstract:
A series of experiments of flat impact between copper flyer and tungsten target has been done on a two stage light gas gun and the diffuse reflectivity of tungsten target to 514.5 nm incident laser was measured under 85～250 GPa shock pressure. The experimental results show that shock compression degrades the reflecting ability of target surface, but the reflectivity doesn't reduce monotonously while shock pressure rises.

Explosive Bulge Test for Metal Tube of Magnetic Flux Compression Generator (MFCG)

YAN Cheng-Li, YU Chuan, LI Liang-Zhong, TONG Yan-Jin

1999, 13(1): 76-80 . doi: 10.11858/gywlxb.1999.01.014

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Abstract:
Metal tube is the important part of MFCG. Its expansive characteristic driven by detonation product is the important basis of the MFCG design. In this paper, the detonation velocity of RDX explosive powder in copper tube was measured by electric method. We derived the detonation velocity of RDX powder (the density was 1.09 g/cm3) was 6.42 km/s. By means of measuring the distance between two electric pins in the metal tube and the time interval of detonation wave traveling, the expansive process of copper tube was measured by optical method with high-speed camera. The average values of expansive angle of the metal tube in three shots were 26.4, 28.5 and 27.3, respectively. Expansive velocity along radius direction was 1.51~1.63 km/s. We have not found any fracture of the tube within the range of the metal tube expanding to two times of the original radius. The results show that the characteristic of the metal tube satisfies the MFCG designs.

1999 Vol. 13, No. 1

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