高压物理学报

Theoretical Problems of Temperature Measurement in Sample under Shock Wave

ZHANG Guan-Ren

1992, 6(4): 241-246 . doi: 10.11858/gywlxb.1992.04.001

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Abstract:
In this paper, the theoretical methods of thermal relaxation at interface following shock compression are reviewed. In contrast to the method adopted by R. Grover and P. A. Urtiew, the author solved the problem by the method of non-Fourier heat conduction. The result is in good accord with the experimental result which is difficult to interpret by the method of Fourier heat conduction theory, and when the time approaches infinite; both methods are coincident with each other. The interpretation of the physical reasons is discussed as well.

Flattening of Cylindrical Shells under External Uniform Pressure at Creep

Shesterikov S A, Lokochtchenko A M

1992, 6(4): 247-253 . doi: 10.11858/gywlxb.1992.04.002

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Abstract:
Experimental studies of the deformation of cylindrical shells under creep to fracture conditions are described in this paper. Analyses of three series of test shells are given and experimental and theoretical results are compared with each other.

Equation of State of Solid Argon under High-Pressure up to 100 GPa

XIN Bing, ZOU Guang-Tian

1992, 6(4): 254-263 . doi: 10.11858/gywlxb.1992.04.003

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Abstract:
Based on the latest X-ray diffraction experiment data and the atomic elastic differential cross-section measurement of argon, we obtained Ar-Ar interaction potential and the equation of state (EOS) for solid argon under 350 GPa. This EOS may be used as the ultrahigh pressure gauge above 150 GPa, which is urgently required in current high-pressure research. Solid argon can not only be used as the pressure transmitting medium for quasi-static hydraulic pressure, but also as a pressure gauge for high-pressure X-ray diffraction measurement. In this paper, we also calculated the value of Grneisen parameter, Debye character temperature, constant volume specific heat, isothermal bulk modulus and their pressure dependence for solid argon in the pressure range from 0~150 GPa.

The Launching Technique of Hypervelocity Projectiles in Two-Stage Light Gas Gun

WANG Jin-Gui

1992, 6(4): 264-272 . doi: 10.11858/gywlxb.1992.04.004

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Abstract:
The launching technique to enhance the projectile velocities of a two-stage light gas gun was studied in this paper. The effects of various filling parameters on the projectile velocities were discussed in detail by numerical calculation. We find that higher projectile velocities can be obtained with less powder charges by reducing the projectile mass, piston mass and gas pressures. Presently, we have obtained velocities of 7.2 km/s, 5.7 km/s and 7.4 km/s for projectiles with weight of 30 g, 60 g and 26 g respectively, when the powder charge is 5 kg. When the filling is 3.5 kg, a projectile weighing 10.3 g achieves a velocity of 8.1 km/s.

Growth Mechanism of cBN by Metal Films

ZHANG Tie-Chen, MA Wen-Jun, GUO Wei-Li, XU Xiao-Wei, ZOU Guang-Tian

1992, 6(4): 273-278 . doi: 10.11858/gywlxb.1992.04.005

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Abstract:
By using Ca3B2N4 as catalyst and treating hBN-Ca3B2N4 under high pressure and high temperature, we obtained cBN crystals covered with metal films at the junction of hBN and catalyst layer. This shows that the formation mechanism of cBN is similar to that of diamond. In this way, nuclei of cBN formed first at the contact face between hBN and catalyst wherein existed, the metal films between the cBN and solvent. The cBN cells move through the films and precipitate on the nuclei of cBN. As the films move toward the solvent, the cBN crystals become larger and larger. The films play an important role in the transfer of cBN cells.

Study of Mg3N2 and Mg3B2N4 Catalysts in cBN Synthesis

XU Xiao-Wei, ZOU Guang-Tian, ZHANG Tie-Chen, GUO Wei-Li, MA Wen-Jun, GUO Xue-Bin

1992, 6(4): 279-284 . doi: 10.11858/gywlxb.1992.04.006

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Abstract:
This study confirms experimentally that both of the low pressure phase of the Mg3B2N4 and Mg3N2-BN will convert to the same high pressure phase of Mg3B2N4 under high pressures and high temperatures. The similarities and the differences between Mg3B2N4 and Mg3N2 catalysts are discussed. We point out that the low pressure phase of Mg3B2N4 will be favorable to the synthesis of cBN.

The Influence of High Pressures on the Luminescence of Ion Exchanged Eu(Ⅲ)NaA and Eu(Ⅲ)NaY Zeolite

LIU Xiao-Yang, SU Wen-Hui, SUN Jia-Yue, PANG Wen-Qin

1992, 6(4): 285-290 . doi: 10.11858/gywlxb.1992.04.007

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Abstract:
The phase transitions of aluminosilicated microporous materials under high pressure have been investigated. The influence of pressure on the luminescence of exchanged Eu(Ⅲ)NaA and Eu(Ⅲ)NaY is discussed. Experiment shows that pressure has a notable influence on the Eu(Ⅲ) ions spectral structures. For the sample of exchanged Eu(Ⅲ)NaY, the value of Im/Ie decreases with increasing of pressure, and for the exchanged Eu(Ⅲ)NaA, the value of Im/Ie increases with increasing of pressure. This difference is due to the different base materials.

Synthesis of Jadeite Jewel and Its Thermal Behavior and Stability

ZHAO Ting-He, YAN Xue-Wei, CUI Shuo-Jing, CHEN Jiu-Hua, LIU Li-Jun, NIU Wei, ZHAO Wei

1992, 6(4): 291-296 . doi: 10.11858/gywlxb.1992.04.008

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Abstract:
Jadeite is synthesized at pressure of 3.0~5.0 GPa, temperature of 1 200~1 550 ℃, for a time duration of 5~240 min from its glass composition of NaAlSi2O6. The jadeite jewel is obtained in our experiment with a size of 12 mm in diameter and 6 mm in thickness. The melting points are studied by DTA and high temperature quenching at high pressure. The thermal stability is studied by quenching, annealing, and aging experiment, which shows that the synthetic jadeite jewel, whose optimum crystalline conditions are over 4.5 GPa, 1 400 ℃, 60 min, has been same thermal stability as that of natural jadeite.

Effects of Series Sharp Laser Pulse on the Melting and Heat Force of Aluminum Alloy Plates

ZHANG Ke-Xing, LIU Xu-Fa, LIU Chang-Ling, SUN Cheng-Wei

1992, 6(4): 297-306 . doi: 10.11858/gywlxb.1992.04.009

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Abstract:
By use of the metalloscopy and scanning electron microscopy, we have studied the fracture mechanism of aluminum-alloys (LY12CZ and LF6M) plates when irradiated by a quasi-condinuous laser beam with series of sharp pulses. Melt pool formed in the laser radiation region, and many cracks appeared, due to the laser induced thermal stress. The relationship of the thermal stress and crack spreading stress with the incident laser intensity were obtained by this investigation.

1992 Vol. 6, No. 4

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