knowledge of professional and technical personnel Notice on the organization of advanced research class on high-pressure science and new materials of engineering

2000 Vol. 14, No. 4

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A Method to Estimate Temperature Coefficient of Sound Velocity at High Pressure
GONG Zi-Zheng, HUA Jing-Song, JING Fu-Qian, XIE Hong-Sen, GUO Jie
2000, 14(4): 241-246 . doi: 10.11858/gywlxb.2000.04.001
PDF (845)
Abstract:
A method to calculate the temperature coefficients of sound velocity at high pressure were given, in terms of the definition of sound velocity and thermodynamics. For perovskite-enstatite, the calculated temperature coefficients of compression, shear and bulk wave velocities decease from 0.386, 0.251, 0.255 m/(s#8226;K) at 40 GPa to 0.298, 0.188, 0.204 m/(s#8226;K) at 80 GPa, 0.244, 0.148, 0.175 m/(s#8226;K) at 120 GPa and 0.197, 0.131, 0.162 m/(s#8226;K) at 140 GPa, respectively. Extrapolating these to zero pressure gives (dK/dT)0=-0.027 9 GPaK-1,which is consistent well with the value from hydrostatic experiment.
In Situ Energy Dispersive Diffraction under High Pressure Using Synchrotron Radiation
LIU Jing, ZHAO Jing, CHE Rong-Zheng, YANG Yang
2000, 14(4): 247-252 . doi: 10.11858/gywlxb.2000.04.002
PDF (744)
Abstract:
Synchrotron radiation can be used to measure the equation of state and phase transition of materials under high pressure. The method of energy dispersive X-ray powder diffraction in diamond cell and the in-situ process of synchrotron radiation experiments developed at Beijing Synchrotron Radiation Facility are described in this paper.
An Approximate Relation between Cubical Thermal Expansion Coefficient of Solid and Pressure
YAN Zu-Tong
2000, 14(4): 253-256 . doi: 10.11858/gywlxb.2000.04.003
PDF (1033)
Abstract:
Assuming that the Anderson-Grneisen Parameter T(T, p)=T(T, 0), an approximate relation between cubical thermal expansion coefficient of solids and pressure was derived using the modified Tait equation. Calculated results are in good agreement with experimental data for NaCl in the pressure range of 0~1 GPa and the temperature range of 300~800 K.
Shock-Wave Nanocrystallization of Fe73.5Cu1Nb3Si13.5B9 Alloy Its Characteristics
LIU Zuo-Quan, ZHANG Yuan-Di, Lü Yu-Song
2000, 14(4): 257-263 . doi: 10.11858/gywlxb.2000.04.004
PDF (704)
Abstract:
Shock-wave and annealing crystallizations of alloy FINEMET were studied using XRD, DSC and TEM. It was found that amorphous FINEMET samples transformed into nanocrystals with grain size of 30～50 nm under shock loading. Comparing with annealing crystallization, many characteristics in the shock wave crystallization can not be explained using diffusion theory. The shock wave nanocrystallization of amorphous alloy contains plentiful physical connotation.
Investigation on Shock and Heat Waves in Aluminum Irradiated by Laser
JIANG Shao-En, YANG Jia-Min, DING Yao-Nan, LIU Yong-Gang, HU Xin
2000, 14(4): 264-268 . doi: 10.11858/gywlxb.2000.04.005
PDF (708)
Abstract:
Al targets with several thickness were irradiated using 1.06 m laser on 'Xingguang Ⅱ' laser facilities. Investigation on the interactions among shock wave, heat wave and sparse wave was primarily done. It was successfully observed that shock wave is in front of heat wave. The related diagnostic methods were developed.
Cd1-xZnxTe Electrical Properties, the Equation of State and Phase Transitions under High Pressure
BAO Zhong-Xing, CHU Jun-Hao, LIU Cui-Xia, LIU Ke-Yue, WANG Jin-Yi
2000, 14(4): 269-272 . doi: 10.11858/gywlxb.2000.04.006
PDF (784)
Abstract:
Resistance-and capacitance-pressure relationships for Cd1-xZnxTe (x=0.04) at room temperature and in the pressure range up to 17 GPa were measured in a diamond anvil cell. Experimental results indicate that Cd1-xZnxTe (x=0.04) undergoes two electronic structure transitions at about 3.1 GPa and 5 GPa, and two crystal structure transitions at above 3.1 GPa and about 5.7 GPa. p-V relationship for Cd1-xZnxTe (x=0.04) at room temperature and in the pressure range up to 4.5 GPa was also obtained using a piston-cylinder type device. Experimental results show that a phase transition in Cd1-xZnxTe (x=0.04) occurs at about 3.8 GPa. Its equations of state before and after the phase transition, Grneisen parameter 0, bulk modulus B0 and the first order pressure derivative B0 of B0 are also given.
Experimental Determination of Diffusion Coefficients of Ions in Aqueous Fluids at Elevated Temperatures and Pressures
SU Gen-Li, XIE Hong-Sen, DING Dong-Ye, GUO Jie, SUN Qiang
2000, 14(4): 273-279 . doi: 10.11858/gywlxb.2000.04.007
PDF (778)
Abstract:
Diffusion coefficients of ions in aqueous fluids are used to predict mass transfer in many geochemical processes quantitatively. The limited molar conductivities of dilute aqueous potassium chloride solutions were determined by electrical conductance measurements from 100 to 500 ℃ and pressure up to 1 200 MPa. Tracer diffusion coefficients were calculated from the limited molar conductivities of ions using Nernst-Einstein equation. The tracer diffusion coefficients increase with temperature and decrease slightly with increasing pressure.
LS Method in Body-Fitted Coordinate System for Multi-Dimensional Non-Ideal Detonation Propagation
CHEN Sen-Hua, ZHANG Xu, BAI Jin-Song
2000, 14(4): 280-284 . doi: 10.11858/gywlxb.2000.04.008
PDF (861)
Abstract:
An algorithm in body-fitted coordinate system for multi-dimensional non-ideal detonation propagation is studied. Stable ENO difference scheme, the treatment of boundary conditions and numerical results are described. The algorithm is of special benefit for computing non-ideal detonation propagation in explosives with curve surfaces.
The Effect of Shock-Heated Gaseous Helium and Argon on Pin Shortening
TANG Jing-You, WU Shao-Zhen, WANG Fan-Hou, GU Yan, DONG Qing-Dong
2000, 14(4): 285-290 . doi: 10.11858/gywlxb.2000.04.009
PDF (565)
Abstract:
Different signals from pins in shock-heated gaseous helium and argon were observed. Assuming that shock wave in gases was one-dimensional and local equilibrium of thermodynamic was reached during shock loading, the state parameters of these two gases were calculated. It is shown that ionization degree for argon exceed 1% when the velocities of flyers ranged from 3 to 5 km/s, this ionization may cause pins shortening before flyers impact pins. However, helium gas was hardly ionized, in which pins work normally.
Electrical Response of PVDF Film under Shock Loading
WEN Dian-Ying, LIN Qi-Wen
2000, 14(4): 291-297 . doi: 10.11858/gywlxb.2000.04.010
PDF (768)
Abstract:
The electrical response of PVDF film along polarization direction under shock loading was studied experimentally and numerically. The release charge profiles, q(t), from PVDF under loading were obtained. The relation between maximum released charge and peak pressure was given. Also, the numerical simulation method for PVDF response for shock loading was developed.
Structures and the Equation of State of Hg1-xCdxTe under High Pressure
GU Hui-Cheng, CHEN Liang-Chen, CHU Jun-Hao, BAO Zhong-Xing, LIU Ke-Yue, WANG Jin-Yi, ZHENG Kang-Li
2000, 14(4): 298-301 . doi: 10.11858/gywlxb.2000.04.011
PDF (927)
Abstract:
Phase transitions of Hg1-xCdxTe (x=0.19) were observed by X-ray powder diffract ion technique with a diamond anvil cell (DAC) at pressures up to 10.1 GPa. At ambient pressure Hg1-xCdxTe (x=0.19) has zinc-blended structure. Two phase transitions in Hg1-xCdxTe (x=0.19) we observed experimentally. The first appears at ～3 GPa, and the second between 6.8 and 8.3 GPa. The second phase transition is believed to be related with metallization of Hg1-xCdxTe (x=0.19). Based on our experimental results, its equation of state in the pressure range of 0~3 GPa was also obtained.
Monopropellant Droplet Microexplosions under High Pressure and Temperature
YU Yong-Gang, JIN Zhi-Ming
2000, 14(4): 302-308 . doi: 10.11858/gywlxb.2000.04.012
PDF (622)
Abstract:
The properties of micro-explosions of monopropellant LP1846 droplets in ambient conditions of 0.2～4.0 MPa, 673～973 K were investigated using a suspended droplet apparatus and a high speed camera. Three modes of micro-explosions, i.e., slight fragmentation of droplets before ignition, part and full fragmentations of droplets during burning period, were observed under different pressure and temperature, and characteristic photographs of droplet micro-explosions were given. Micro-explosion delay time, temperature and diameter of droplets were also measured quantitatively. Droplet micro-explosion mechanisms were analyzed primarily. It is suggested that the mechanisms of the three modes are the overheating of water component for the first mode, and liquid phase reactions, respectively. The results are of reference value to control combustion stability of LP1846 and design interior ballistics of regenerative liquid propellant guns.

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