高压物理学报

Numerical Simulation on the Spallation of a Steel Cylindrical Shell Imploded under Slipping Detonation

DONG Yu-Bin, SU Lin-Xiang, CHEN Da-Nian, JING Fu-Qian, HAN Jun-Wan, FENG Jia-Bo

1989, 3(1): 1-10 . doi: 10.11858/gywlxb.1989.01.001

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Abstract:
The spallation experiment of a steel cylindrical shell imploded under slipping detonation was reported by Иванов et al., but the measured and calculated results, showed in that paper, are not in accord very well in values. In this paper, we utilized the method of damage-level function to carry out the numerical studies for the above experiment. The calculated spall locations are quite in accord with that of the Ивановs experiment. It is illustrated that the method of damage-level function we adopted has a certain universal applicability for studying the dynamic fracture problems. The implosion processes of the steel cylindrical shell used in the Ивановs experiments were also analyzed numerically in this paper. The influences of the critical damage-level c values adopted on the spall locations, the implosion trajectories, and the shell velocity histories were discussed, and the importance of reasonable selection of c value for analyzing the interface-instability problems was also illustrated.

Research on Transparent Boron-Skin Diamond Formed with Natural Diamond

ZHANG Qing-Fu, GOU Qing-Quan, LIU Lü-Hua, HE Ming

1989, 3(1): 11-17 . doi: 10.11858/gywlxb.1989.01.002

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Abstract:
This paper presents a little boron permeated on the surface of natural diamond to form boron skin with the ion implantation method. Tests are done to find whether its heat resistance might be improved. A low-energy ion-implantation device has been designed and improved. Two sources (B2O3 and pure boron) have been implanted to the natural diamond with four energies (8.0, 6.5, 4.5 and 2.5 keV). Boron-skin forms on the surface of diamond. The surface of diamond remains to be colorless and transparent after implantation. On the surface of the natural diamond the B1s peak can't be found by XPS test. It is assumed that no boron atoms exist on the diamond surface. But after ion implanting, obvious B1s peak is found on the surface of natural diamond, then its surface structure is analyzed with the surface testing. Tests show that boron atoms and carbon atoms on diamond surface form a boron-carbon structure. After TGA tests, the heat resistance has been improved in almost the same degree when four kinds of energy are used. But it is better when pure B is used than B2O3. It also shows that heat resistance of boron-skin diamond is only dependent upon the B atoms on the surface and is not upon the B atoms below the surface.

Pressure Effect on Structural Relaxation of Zr70Cu30 Amorphous Alloy on Annealing

CHEN Gui-Yun, YIN Xiu-Jun, ZHANG Yun, LIU Zhi-Yi, SHEN Zhong-Yi

1989, 3(1): 18-24 . doi: 10.11858/gywlxb.1989.01.003

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Abstract:
The relaxation behavior of superconducting transition temperature (Tc), which to a great extent may characterize the geometric short-range ordering process in amorphous alloys was examined on Zr70Cu30 metglas on pressure annealing below its gasification temperature. The obtained results show that Tc degradates on raising of annealing temperature and prolongation of tempering. Pressure shows a relation effect to Tc relaxation process, while it still remain a logarithmic character in kinetics as at normal pressure. This behavior could be explained by the reduction of local expanded region in amorphous structure during external pressing.

Study on the High Pressure Synthesis of Transparent Boron Skin Diamond

GOU Qing-Quan, CAO Guo-Ying, DING Li-Ye, LIU Xiao-Ping

1989, 3(1): 25-30 . doi: 10.11858/gywlxb.1989.01.004

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Abstract:
According to the theoretical model of boron skin diamond, a new kind of transparent light-yellow diamond has been produced from graphite by micro doping with boron to a certain content and distribution. It has high strength and good thermal stability and its antioxidation temperature is 200 ℃ higher than that of yellow diamond.

Resistivity and Hugoniot Measurements of Polytetrofluoroethylene (Teflon) under Shock Compression

GU Cheng-Gang, JING Fu-Qian, XIE Pan-Hai, WANG Jin-Gui

1989, 3(1): 31-41 . doi: 10.11858/gywlxb.1989.01.005

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Abstract:
Experimental results of resistivity and Hugoniot measurements for the Teflon of home-made (SFB-1) in the pressure range of 10~45 GPa are reported in this paper. The main results are: the resistivity is a monotonous decrease function of pressure, from 2.45105 #8226;cm at 10 GPa to 1.73103 #8226;cm at 45 GPa, and the corresponding shock adiabat may be expressed as D=1.571+1.961u-0.0537u2 (D, u are shock velocity and particle velocity, respectively, both units are in km/s). In comparison with the data reported by others, it is found that there exists definite difference in the values of resistivity of the Teflon samples made by different factories, but in the shock adiabat expressed as D-u relation there is no detectable difference.

High-Pressure and Temperature Syntheses and Structural Stability Studies of Some Rare-Earth Oxides

LI Qiang-Min, SU Wen-Hui, LONG Xiang, WU Dai-Ming, GAO Zhong-Min

1989, 3(1): 42-50 . doi: 10.11858/gywlxb.1989.01.006

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Abstract:
By using high pressure and temperature method for the first time and under the conditions of 3.2~4.0 GPa, 1 000~1 300 ℃, the synthetic experiments for the rare earth oxide systems of CeO2-R2O3 (R=Eu, Gd), CeO2-Tb4O11, Pr6O11-Tb4O7 were made, and the products of F-CeEuO3.5, -CeGdO3.5, -CeTbO3.5; B-CeEuO3, -CeGdO3, -CeTbO3 and B-PrTbO3, P-PrTbO3 were obtained. The PrTbO3 is a new material which has not been discovered in natural world up to date. The structural stability of the above products and NdYbO3, PrTmO3 has been measured by using high and low temperature X-ray powder diffraction method. The results indicated that some structural transformations from B-CeROx to F-CeROx (R=Eu, Gd, Tb) and from B-PrTbO3 to C-PrTbO3 occur at the temperature going from 300 ℃ to 1 000 ℃. The F-CeROx belongs to a fluorite-type structure with oxygen deficiency.

Molecular Dynamics Study on Equation of State

ZHANG Chun-Bin

1989, 3(1): 51-57 . doi: 10.11858/gywlxb.1989.01.007

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Abstract:
We discussed principal problems in studying equation of state by use of molecular dynamics method and calculated EOS of Ar with MD code developed by ourselves (three dimension continuous potential). The calculated results are in agreement with experimental data very well.

Fe26 Equation of State Calculations for Hot Dense Matter at Arbitrary Density and Temperature

XUE Fu-Zeng, LI Zhao-Ning, PAN Shou-Fu

1989, 3(1): 58-66 . doi: 10.11858/gywlxb.1989.01.008

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Abstract:
In the spherical lattice cell, central-field and relativistic Fermi statistics approximations, an algorithm is presented with average atom model to calculate electron levels and the equation of state for hot and dense matter at arbitrary density and temperature. Zink's analytic potential is chosen as starting potential to solve Dirac-Slater equation satisfying the Wigner-Seitz boundary condition. The pressure ionization effects are included by level degeneracy as a founction of density for dense matter. Results are show for Fe26 atom.

Experimental Studies of Hugoniot for Powder Mixture of BaCO3 and TiO2 and Shock Wave Synthesis of BaTiO3

CHEN Xu, JIN Xiao-Gang, YANG Mu-Song

1989, 3(1): 67-77 . doi: 10.11858/gywlxb.1989.01.009

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Abstract:
Hugoniot data for powder mixture of BaCO3 and TiO2 have been measured in the range 10 to 100 GPa according to impedance match principle using chemical explosive driven shock wave and flash gap slit sweeping photography of high speed rotating mirror camera. Recovery experiments with axial symmetric and planar configurations and X-ray diffraction of recovered sample in order to examine shock synthesis of BaTiO3 have conducted as well. Measured Hugoniot curves show obvious discontinuities at about 30 and 45 GPa. Hugoniot data combined with X-ray diffraction analyses show that those discontinuities correspond to the phase transition of TiO2 in the mentioned mixture from the anatase to the -TiO2 phase and synthesized BaTiO3 reaction between BaCO3 and TiO2, respectively. Moreover, X-ray diffraction analyses of recovered samples using ammonium nitrate charge indicate that the very complete transition of TiO2 from the anatase phase to the rutile phase occurred.

Studies of Piezoelectric Behaviors for PVF2 under Dynamic Loadings

SUN Zhu-Mei, HU Dong

1989, 3(1): 78-84 . doi: 10.11858/gywlxb.1989.01.010

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Abstract:
The piezoelectric behaviors of PVF2 (polyvinylidene fluoride) under dynamic loadings (0.01~4 MPa) are studied by means of explosion shock tube. It is found in the experiments that the piezoelectric sensitivity abruptly decreases for the loading pressures larger than 0.25 MPa, and approaches a constant. The crystalline feature of PVF2 under dynamic loadings were observed with a X-ray diffractometer. The results show that it is not obviously changed even undergoing shock loadings of 3~4 MPa for many times.

Bimetallic-Junction Shock Pressure Sensors

ZHANG En-Guan

1989, 3(1): 85-92 . doi: 10.11858/gywlxb.1989.01.011

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Abstract:
This paper briefly describes the behaviors, feature, construction and application of the bimetallic junction sensor. It also presents the construction parameters for three combined types of sensors and their V-p curves under the experimental conditions, which show that there principally exists a linear dependence in the pressure range. Their fitting formulae are also given. The diversity of the experimental results are less than 12% at the pressure of 45 GPa and less than 8% at 80 GPa and 116 GPa, respectively. The pressures induced by the double shock waves and their time interval were measured by type Ⅲ sensor. The obtained results are in good agreement with the predicted values.

1989 Vol. 3, No. 1

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