高压物理学报

Measurement of Radiation Temperature in Hohlraum with Shock Wave Method on 'Shenguang Ⅱ' Laser Facility

JIANG Shao-En, LI Wen-Hong, SUN Ke-Xi, JIANG Xiao-Hua, LIU Yong-Gang, CUI Yan-Li, CHEN Jiu-Sen, DING Yong-Kun, ZHENG Zhi-Jian

2005, 19(4): 289-292 . doi: 10.11858/gywlxb.2005.04.001

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Abstract:
The D shaped cavity has been used to measure the radiation temperature in Hollraum on Shenguang Ⅱ laser facility. The radiation temperature was measured using two methods. One method measured the shock wave velocity produced in low-Z materials such as Al driven by the emission from hohlraum. The shock velocity was detected using optical streaked camera to observe the optical signal emitted from the rear of a step Al placed over a hole in the cavity wall. The second method measured the re-radiated X-ray flux from the cavity wave viewing through another hole in the cavity with soft X-ray spectrometer. Both methods have been shown to provide a consistent characterization of the X-ray drive in the cavity target. The experimental results were analyzed using a model that was based on heat wave similarity and energy conversation law.

Elastic P Wave Velocity and Attenuation in Dunite up to 4.0 GPa

LIU Wei, DU Jian-Guo, XIE Hong-Sen, ZHOU Wen-Ge, GUO Jie

2005, 19(4): 293-298 . doi: 10.11858/gywlxb.2005.04.002

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Abstract:
Elastic P wave velocity (vP) and quality factor value (QP, on behalf of attenuation) of dunite are determined using ultrasonic pulse transmission and spectral ratio methods in a multi-anvil apparatus up to 4.0 GPa at room temperature. During the experimental pressure range (0.4~4.0 GPa), vP and QP increase about 11.8% (from 7.6 km/s to 8.5 km/s) and 393.3% (from 54 to 266.4). The experimental results show that vP and QP are pressure dependent and a greater rising rate at the lower pressures than that at higher pressures: the increase rate of QP at 0.4~2.4 GPa is 358.5%, while only 7.6% at 2.4~4.0 GPa. At the lower pressures, the pores with low aspect ratio in rocks are easy to close, and almost all of them would close with the pressure increasing. As a result, the samples show the internal inherent elasticity of the whole constituent minerals themselves and the increasing rate of vP turns lower at the higher pressures. As the pressure rising (0.4~2.4 GPa), QP of dunite increases because the energy loss in the pores and between the surfaces of cracks and the mineral boundaries is reduced due to the porosity decreasing and the mineral boundaries contact more tightly. While at higher pressures (2.4~4.0 GPa), most microcracks in dunite have been closed and mineral grains are compacted very tightly, as a result the internal frictional energy loss due to the relative motion at the grain boundaries and across crack surfaces became less, which results in small change of elastic wave attenuation in dunite.

The Application of Quartz Transducer Technique in SHPB

LIN Yu-Liang, LU Fang-Yun, LU Li

2005, 19(4): 299-304 . doi: 10.11858/gywlxb.2005.04.003

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Abstract:
During testing low impedance materials (so-called soft materials) by a conventional split Hopkinson pressure bar (SHPB), the transmission strain pulse is too weak to be collected correctly. In addition, the soft material specimen will not deform homogeneously during the testing, which makes it impossible to get valid data. In this paper, a polyurethane foam material was tested by SHPB using a quartz transducer technique. The stress equilibrium in the specimen was monitored by quartz transducer mounted at two end faces of the specimen. Experimental results showed that the amplitude of transmitted signals were increased greatly. Meanwhile, we used a pulse-shaper technique to increase the rise time of the incident pulse, which could ensure stress equilibrium and homogeneous deformation in the specimen. Compressive stress-strain behaviors of the foam showed that there was little effects of strain rates on the material properties at strain-rate of 1 000~4 000 s-1.

Pressure Induced Rice Mutation and ISSR Analysis of the Mutants

XU Shi-Ping, GUO Li-Xiu, WENG Ke-Nan, DUAN Jun, Lü Guang-Cai

2005, 19(4): 305-311 . doi: 10.11858/gywlxb.2005.04.004

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Abstract:
After up to 10 generations of purification by strict self-fertilizing, seeds of two rice varieties (Oryza sativa L.), Yuexiangzhan and Bijing-38 were treated with high hydrostatic pressure during last 5 years, and 5 contemporaneous mutants and 4 descendant natural mutants were obtained with high reproducibility for the contemporaneous mutants. To verify if the mutation was take place at DNA level, Inter Simple Sequence Repeat (ISSR) analysis of the original rice varieties and mutants was conducted. The analysis revealed that the genetic substance (DNA) had been altered. Evidently, the mutation was induced by high hydrostatic pressure treatment. Generally, the mutation took place contemporaneously and the new characters are of high genetic stability; the further the genetic distance between the mutant and the original is, the higher the genetic stability of the mutant is.

The Damage Evolution Equation and the Spallation Criterion of Al-Li Alloy

GUO Yang, LI Yong-Chi, CAO Jie-Dong, LI Jian-Guang

2005, 19(4): 312-318 . doi: 10.11858/gywlxb.2005.04.005

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Abstract:
The spallation experiments of Al-Li alloy have been carried out and the free surface velocity temporal curves for the spallation events have been measured. Based on the microscopics statistics and phenomenological analysis, a damage evolution equation is developed, which involves the effects of the growth and nucleation of microcavities as well as the effects of the material's compressibility. Inserting the constitutive equation and Murnagham state equation of Al-Li alloy and the damage evolution equation into ANWP, which is a special program for one-dimension strain wave, and by the numerical simulation of the free-surface velocity temporal curve for the spallation events in the gas gun experiments, we have obtained the related parameters in the damage evolution equation and the spallation criterion.

Propagation of Stress wave and Spallation of Cylindrical Tube under External Explosive Loading

SUN Yu-Xin, ZHANG Jin, LI Yong-Chi, HU Shi-Sheng, DONG Jie

2005, 19(4): 319-324 . doi: 10.11858/gywlxb.2005.04.006

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Abstract:
The deformation and spalling behavior of the cylindrical steel tube under external explosive loading was studied. On the basis of the damage evolution equations and considering damage and temperature softening effects, we obtained the explicit plastic constitutive relations. Numerical simulations were carried out and the computational results were analyzed. The satisfactory agreement between the computational results and the experimental ones shows that the constitutive relations and computational method presented in this paper are reasonable and of important in practical usage.

A Numerical Simulation to Dynamic Buckling of Magnetically Imploding Liner

SONG Sheng-Yi, CHEN Gang

2005, 19(4): 325-330 . doi: 10.11858/gywlxb.2005.04.007

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Abstract:
With the aid of instant nonlinear finite element method, a numerical simulation to dynamic buckling of the implosion liner driven by magnetic pressure has been carried out. The principle of the method and the results of simulation has been introduced and discussed. The comparison of simulation results with experimental ones indicated that the simulation method established by this paper are validated and can be used as a useful tool for the study of liner implosion buckling.

Pressure Effects on the Elastic Properties of the hcp Lithuim

CHEN Chang-Bo, CUI Tian, LIU Zhi-Ming, ZOU Guang-Tian, WEI Meng-Fu, CHEN Chang-An

2005, 19(4): 331-336 . doi: 10.11858/gywlxb.2005.04.008

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Abstract:
The elastic constants of bulk lithium with hexagonal close-packed (hcp) structure under high pressures have been calculated, by using Density Functional Theory and the relationship between stress and strain. From our results, C12 and C13 increase linearly with pressures, but pressure effects on C44 and C66 are not obvious. At each pressure, C33 is bigger than C11, indicating rigidity of lithium in z direction is harder than that in x, y direction. It has been found that C11 and C33 have step-like changes in the phase transition zone. The results of the compressional wave anisotropy (p) show that p is equal to 1 at zero pressure and still near 1 under high pressure, meaning hcp lithium have the compressional elastic isotropy. The shear wave anisotropy (s1, s2) are away from 1 and this tendency increases with the increasing of pressure, showing the shear elastic anisotropy. Pressure effects on the Cauchy relations and the normalized elastic constants of hcp lithium are also discussed in this paper.

Micro-Failure Mechanism Analysis and Test Study for Rock Failure Surface under Water Jet Impact

LI Gen-Sheng, LIAO Hua-Lin

2005, 19(4): 337-342 . doi: 10.11858/gywlxb.2005.04.009

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Abstract:
The rock breaking mechanism by water jets impact has not been clearly recognized as yet for complicated process of rock damage. The test of cutting rocks with submerged high-pressure water jets impact by a numerical controlling jet cutting machine are conducted. Then, the test for the pattern of failure surface of cutting slots and dilapidated slices are performed with scanning electron microscope (SEM) to study micro failure mechanism of rocks with water jets impinging. The result shows two types of rectangle shape and shallow funnel shape craters in the rock matrixes. The analysis shows that the micro-mechanism of rock failure due to water jets impingement is a brittle fracture in the condition of tensile and shearing stress.

Analysis of Two Stages Explosive/Flyer System

WEN Shang-Gang, DENG Wen-Rong, ZHAO Feng, SUN Cheng-Wei

2005, 19(4): 343-347 . doi: 10.11858/gywlxb.2005.04.010

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Abstract:
The driving abilities of strong detonation in two stages explosive/flyer system have been studied by both analysis and experiments. Under certain condition, the system's geometric parameters are optimized in order to drive final flyer to high speed. The abilities of strongly detonating explosive slab in driving metallic flyers to high speed are shown in our calculation model. Calculated results agree with experimental results. The performances of strong detonation are illustrated. And numerical calculation shows that converging detonation can be an effective method to accelerate a flyer up to high speed.

Contribution of Lattice Vibration and Hot Electron to the Shock Compression Behavior of Porous Metal

YANG Mei-Xia, LIU Fu-Sheng, SUN Yu-Huai, ZHANG Dai-Yu

2005, 19(4): 348-352 . doi: 10.11858/gywlxb.2005.04.011

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Abstract:
Based on the Debye mode, electron gas model, and Grneisen equation of sate, new formula were deduced which describe the individual contributions of lattice vibration and hot electron to shock temperature, shock pressure and compression volume of porous metals. It is found that the contribution of lattice vibration to shock compression volume accord with W-J equation; meanwhile, the contribution of hot electron to shock compression volume also can be calculated by the improved equation. In this paper, we especially discussed the reliability and the physical meaning of the new equations.

Density-Functional Calculation of the EOS and Adiabatic Elastic Properties for Solid Argon

MENG Chuan-Min, JI Guang-Fu, HUANG Hai-Jun

2005, 19(4): 353-356 . doi: 10.11858/gywlxb.2005.04.012

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Abstract:
DFT-LDA method has been performed on calculations for fcc structure solid agon. The equation of state and adiabatic elastic properties of solid argon has been calculated up to 82 GPa. The results are in good agreement with the experimental data. The calculation indicates that the elastic properties and p-V relationship of solid argon can be obtained with local density approximation. If the parameters for calculation can be chosen properly, the elastic properties and p-V relationship of solid argon can be calculated exactly and save large of resource of computation at the same time.

Pressure Induced Phase Transition of Nano Zinc Sulfide Shell

WANG Lin, LIU Bing-Bing, WANG Hui, HOU Yuan-Yuan, AI Xiao-Lei, PAN Yue-Wu, CUI Qi-Liang, ZOU Guang-Tian, LIU Hong-Jiang, NI Yong-Hong, et al.

2005, 19(4): 357-360 . doi: 10.11858/gywlxb.2005.04.013

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Abstract:
In situ energy dispersive X-ray diffraction measurements on nano zinc sulfide shell have been carried out by using diamond anvil cell with synchrotron radiation. The highest pressure is 33.3 GPa in the experiment. The raw materials contain two structures of ZnS, which are wurtzite and zinc blende respectively. With increasing pressure, the wurtzite structre was transformed to zinc blende structure at 11.2 GPa. A phase transition from zinc blende structure to rocksalt structure occurred as the pressure reached to 16.0 GPa. Two unknown diffraction peaks were found in the range of pressure from 17.5 GPa to 21.0 GPa. The rocksalt structure existed as the pressure reached to 33.3 GPa. Both of the phase transitions are reversible.

Simulating the Dynamic Release Behavior of Copper

PENG Jian-Xiang, ZHOU Xian-Ming, SONG Ping, ZHANG Lin, WANG Li-Li, JING Fu-Qian

2005, 19(4): 361-364 . doi: 10.11858/gywlxb.2005.04.014

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Abstract:
The dynamic release behavior of OFHC copper under 10~20 GPa shock pressure was simulated by using the Johnson-Cook (JC) constitutive model and Steinberg-Cochran-Guinan (SCG) constitutive model, respectively. Comparisons between the simulations and the experimental results show that the strain rate effect during the release process of copper under such shock pressure ranges is still obvious. And the simulation of JC model gives better agreement with experimental results than the simulation of SCG model in which the strain rate effect is ignored.

Melting Temperatures of OFHC Copper under Shock Compression Measured by Optical Radiometry Techniques

ZHANG Ling-Yun, DAI Cheng-Da, XU Can-Hua, TAN Hua

2005, 19(4): 365-370 . doi: 10.11858/gywlxb.2005.04.015

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Abstract:
Melting temperatures of OFHC (Oxygen-Free High Conductivity) copper at pressures ranging from 110 GPa to 140 GPa were measured on a two-stage light-gas gun by optical radiometry techniques and using LiF single crystal as window, based on such a conclusion that the melting temperatures at the sample/window interface pressure is equal to the release temperature, and close to the interfacial temperature if the OFHC copper sample is initially shocked or released into the region adjacent to the liquidus. The obtained data are consistent with the experimental results of high-pressure sound velocity measurements and theoretical predictions, and the melting behavior of OFHC copper at high pressure can be approximately described with Lindemann melting law. The method for melting temperature measurements we proposed in this paper avoided derivation of Hugoniot temperature, which simplified the determination of melting temperature, and provided a potential approach for melting temperature measurements of metals.

Stability of n-Pentane under High Pressure

QIAO Er-Wei, ZHENG Hai-Fei

2005, 19(4): 371-376 . doi: 10.11858/gywlxb.2005.04.016

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Abstract:
Raman scattering spectroscopy was used to investigate stability of n-pentane in Moissanite anvil cell from 0.07 GPa up to 4.77 GPa at ambient temperature. The result shows that CH3 symmetric and asymmetric stretching vibration, CH2 symmetric and asymmetric stretching vibration and －(CH2)n － in-phase twist mode at 2 877 cm-1, 2 964 cm-1, 2 856 cm-1, 2 935 cm-1 and 1 303 cm-1, respectively, shifted to higher frequency according to quasi-linearity with pressure increase, and an abrupt visible change was taken place, indicating that it is a sort of phenomenon of freezing at overpressurization. In addition, a high-pressure transition phase may appear in crystallized n-pentane in the range of 2.84~4.77 GPa. The equilibrium freezing pressure of n-pentane is (1.900.05) GPa at 27 ℃ by measuring with the method of crystal-liquid coexistence.

First-Principle Calculation of the Static Structure and Phase Transition of Aluminium

HOU Yong, ZHANG Dong-Wen, YUAN Jian-Min

2005, 19(4): 377-380 . doi: 10.11858/gywlxb.2005.04.017

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Abstract:
In the framework of density functional theory, the static structure properties and phase transition of aluminium are calculated using the augmented plane wave plus local orbitals (APW+lo) method with generalized gradient approximation (GGA) for the exchang-correlation energy. The critical values for the phase transitions (fcc－hcp, fcc－bcc, hcp－bcc) are 220 GPa, 300 GPa and 380 GPa, respectively. Our results are in consistent with existing data obtained from different methods and also in good agreement with experiments.

Structural Stability and Electrical Properties of CMR Material Sr2CrWO6 under High Pressure

LI Jian-Ru, YANG Liu-Xiang, LI Jie, YU Ri-Cheng, LI Feng-Ying, BAO Zhong-Xing, LIU Jing, JIN Chang-Qing

2005, 19(4): 381-384 . doi: 10.11858/gywlxb.2005.04.018

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Abstract:
The spectra of energy dispersive X-ray diffraction with synchrotron radiation of double perovskite compound Sr2CrWO6 have been studied in situ high pressure pressure up to 34.5 GPa using a diamond anvil cell at room temperature. The experimental results indicate that the sample undergoes a crystal structural change at about 9 GPa. The resistance-pressure and capacitance-pressure relationships in the pressure range of 0~20 GPa show that there is an electronic structural change in Sr2CrWO6 in the pressure range of 2~5 GPa.

Application of the Coupling Method in Simulating the Hypervelocity Impact

WU Yu-Yu, HE Yuan-Hang, LI Jin-Zhu

2005, 19(4): 385-389 . doi: 10.11858/gywlxb.2005.04.019

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Abstract:
Compared to the traditional numerical methods, meshless SPH method is more suitable to simulate the hypervelocity impact in that it can simulate the material interface clearly and overcome the numerical instability due to the large mesh deformation in the Lagrange method. In SPH, in order to get the physical value of one nodal at time t, it is firstly required to find the neighboring nodes interacting with it, so the calculation speed is slower and the calculation time is longer than that of the FEM. This paper adopts the coupling method of SPH and Lagrange to simulate the 3D hypervelocity impact problem. The results show that the coupling method can save largely time while keep the accuracy approximately to that of SPH.

Introduction of the 4th International Symposium on Supercritical Fluid Technology for Energy, Environment and Electronics Applications

SU Lei

2005, 19(4): 390-392 . doi: 10.11858/gywlxb.2005.04.020

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Abstract:
The 4th International Symposium on Supercritical Fluid Technology for Energy, Environment and Electronics Applications was introduced in this report. Progresses on supercritical fluid technology for energy, environment and electronics applications in recent years was described, respectively.

2005 Vol. 19, No. 4

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