高压物理学报

Hugoniot Temperature Measurements for Metals by Using Optical Radiation MethodModel Review and Discussion

DAI Cheng-Da, TAN Hua

2006, 20(2): 113-121 . doi: 10.11858/gywlxb.2006.02.001

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Abstract:
Shock temperature and melting temperature measurements are of importance to construct complete equation-of-states of materials. In this article, we overviewed the one-dimensional heat conduction model at ideal interface and model at non-ideal interface in Hugoniot temperature measurements of metals, focusing on the reasonability or tenability of the inclusive and implicative assumptions in models, and the principal factors influencing the resultant temperature. The discussed issues deal with the assumptions of the heat conductivity at shock compression independent of temperature to derive an analytical solution to the interface temperature, that of the greybody emitter of the sample/window interface at shock compression, the transparency of window under shock temperature, the correction of apparent interface temperature to ideal interface temperature in non-ideal interface model, the measurements for melting temperature under shock compression, and the non-Flourier heat conduction at the interface. The investigations show that the metal-sample/window interfacial radiation measurements can yield an approximate Hugoniot temperature, and even an approximate melting temperature at interface pressure in the case of melting as a whole.

Explosive Synthesis of Nanometer Titanium Dioxide and Parameter Control

LI Xiao-Jie, CHEN Tao, XU Zhao-Long, LI Rui-Yong, QU Yan-Dong, WANG Zhan-Lei

2006, 20(2): 122-126 . doi: 10.11858/gywlxb.2006.02.002

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Abstract:
Some TiO2 nanoparticle samples with size range from 10 nm to 60 nm were prepared by explosive synthesis method. The influence of the preparation parameters on the size and the crystalline phase of the TiO2 crystallite were studied by means of X-ray diffraction (XRD) technique, SEM, TEM and BET. With these characterizing methods, it indicates that the explosive temperature plays a very important role in the crystalline phase transformation. With increasing the proportion of detonator, the size of TiO2 crystallite increased, and the crystalline phase transforms from the low temperature phases of anatase and brookite to the high temperature phase of rutile.

Percolation Description for the Early Stage of Void Coalescence during Dynamic Tensile Fracture in Ductile Materials

WANG Yong-Gang, HE Hong-Liang, WANG Li-Li, JING Fu-Qian

2006, 20(2): 127-132 . doi: 10.11858/gywlxb.2006.02.003

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Abstract:
Based on the frame of percolation theory, a new stress release function named as Percolation Release (PR) function has been proposed to describe the course of stress release during the early stage of void coalescence until the final or catastrophic fracture occurring. A clearly physical meaning is given for Dc0, the critical damage for the initiation of void coalescence, and Df, the fracture critical damage. Coupled with damage function model proposed previously, PR function is applied to simulate the spall behaviors of OFHC copper and 45 steel as examples. Compared with the experimental measurements, numerical results indicate that the calculated stress profile and free surface velocity profile as well as the damage distribution in the materials being studied are consistent well with the experiments, and PR function has a good ability for describing the stress release just before the catastrophic fracture occurs.

Numerical Analysis of Marginal Detonation Dynamics in a Rectangular Tube

WANG Chang-Jian, XU Sheng-Li

2006, 20(2): 133-138 . doi: 10.11858/gywlxb.2006.02.004

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Abstract:
Marginal detonation dynamics in a rectangular tube was numerically analyzed in this paper. The detailed chemical reaction model was employed to describe the heat release of detonation chemical reactions. The 2nd additive semi-implicit Runge-Kutta method and 5th order Weighted Essentially Non-Oscillatory (WENO) scheme were used to integrate the two-dimensional time-dependent reactive Euler equations. For the stoichiometric hydrogen and oxygen mixture diluted by 25% argon, as the channel width is 30 mm and the initial temperature is 300 K, the critical initial pressure for marginal detonation is 3.5 kPa. Under this critical condition, the cellular pattern, the velocity and maximum pressure along the wall and the wave evolution of marginal detonation were obtained. The difference between the marginal and ordinary detonation was discussed including the detonation velocity, average velocity, the ratio of cell width to length, transverse wave structure, unreacted gas pocket and vortex structure. The intrinsic instability and chemical dynamics characteristics of marginal detonation were deeply recognized.

Studies of the Hugoniot Curve for Fe/FeO/FeS Mixture

HUANG Hai-Jun, JING Fu-Qian, CAI Ling-Cang, BI Yan, MENG Chuan-Min

2006, 20(2): 139-144 . doi: 10.11858/gywlxb.2006.02.005

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Abstract:
Hugoniot compression curve for the mixture of Fe/FeO/FeS (58.96%/35.83%/5.21%, mass fraction) has been measured from 50 to 210 GPa, using two-stage light-gas gun and electric pin technique. The measured Hugoniot parameters are: C0＝(3.970.07) km/s, ＝1.580.03 and initial density 0＝(6.690.06) g/cm3. Based on additive volume law, the compressional curves of this mixture along Hugoniot and along 0 K isothermal were also calculated respectively according to the Hugoniot curve and 0 K isothermal relevant to the ingredients, which showed both are consistent well with the experimental Hugoniot and the 0 K isothermal deduced from the experimental Hugoniot using the Wu's method. Thus it demonstrated the rationality of this experimental Hugoniot and the applicability of the additive volume law hold for this mixture. For the letter, it also implies that no detectable chemical reactions happen between Fe, FeO, FeS ingredients while they were subjected to shock compression in this work. The above mentioned results provide a basis for investigating the candidate concentrations of Earth's outer core if it is a Fe-O-S assembly, for the further details.

Sound Velocity Measurements for Shock-Compressed LY12 Aluminum Alloy by Using VISAR Technique

YU Yu-Ying, TAN Hua, HU Jian-Bo, DAI Cheng-Da, MA Yun, CHEN Da-Nian

2006, 20(2): 145-152 . doi: 10.11858/gywlxb.2006.02.006

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Abstract:
The experimental method to measure the high-pressure sound velocity of shock-compressed LY12 aluminum alloy by VISAR technique is described. Symmetrical plate impact experiments were conducted with the two-stage light-gas gun and at peak stresses about 20, 32, 55 and 71 GPa, respectively. In each shot, a VISAR system with three different fringe-constants was used to measure the particle-velocity profile at the interface between the test sample and the single crystal LiF window. The particle velocity histories deduced from three fringe numbers in each shot coincided with each other excellently. The high signal to noise experimental records also demonstrated that the joint and the treatment of the interface between the sample and the window were very successful. Beside the longitudinal sound velocities at the initial shock stresses, also produced were the sound velocity histories along the release paths, from which the bulk sound velocities at the initial shock stresses were determined by extrapolating the plastic portion of the sound velocity history. These results were consistent with the calculations obtained through Mie-Grneisen equation of state under the assumption that =constant.

Calculation of Shock Temperature by Considering Electronic Contribution

RAN Xian-Wen, TANG Wen-Hui, TAN Hua, DAI Cheng-Da

2006, 20(2): 153-156 . doi: 10.11858/gywlxb.2006.02.007

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Abstract:
Basing on the former shock temperature calculation methods, a new method was proposed, which considered the electronic contribution and successfully avoided the difficulties of calculating 0 K EOS of materials. By applying it to aluminum and copper, the results were well consistent with experimental data. And the calculated onset of melting on the Hugoniot curves of aluminum and copper were (125.5 GPa, 4 705 K) and (231 GPa, 5 369 K), respectively, in good agreement with the presented experimental data of aluminum and copper.

Investigations on Combustion and Explosion Process of Suspended Aluminum Particles in a Large Combustion Tube

CHEN Zhi-Hua, FAN Bao-Chun, LI Hong-Zhi

2006, 20(2): 157-162 . doi: 10.11858/gywlxb.2006.02.008

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Abstract:
The combustion and acceleration mechanism of aluminum particles has always been the focus of some related research institutes, due to its potential application value. In the present paper, to further the investigation of combustion and propagation characteristics of aluminum particles in a limited space, the two-fluid model, turbulent k- model and combustion model of aluminum particles have been introduced to simulate the combustion propagation of aluminum suspension flow in a large horizontal tube. The SIMPLE scheme has been adopted as the main calculating method to simulate the whole propagation process of two-phase, aluminum particles-air flow in a large and long horizontal tube. The time history of all parameters of two-phase flow during the combustion and propagation process has been revealed based on our calculated results, which agrees well with our previous experimental results.

Modelling Synthesis in Laboratory of Coesite in the Earth's Crust and Its Formation Mechanism

LIU Shu-E, XU Da-Peng, LIU Xiao-Mei, SU Wen-Hui, XUE Yan-Feng, SUN Jing-Shu

2006, 20(2): 163-171 . doi: 10.11858/gywlxb.2006.02.009

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Abstract:
The factors of collision and shear stress in the coesite formation has not been considered in the condition of high static pressure that was the base of the hypothesis of subduction-return of slab in the Earth. After considered these factors, a laboratory method of combining the high-energy mechanical ball milling ( HEMBM ) and high static pressure was suggested in this paper for modelling synthesis of coesite in the Earth's crust. A mechanical collision-induced intermediate phase of -quartz has been discovered. Its condition of easily crystallizing into coesite induced by high static pressure is 3.0 GPa, 932 K, and 1.0 min. The Raman peaks for the coesite synthesized by the present method have covered over the all information of those natural and synthesized coesite obtained before. This implicated that the coesite in the Earth's crust and subduction-return of slab maybe not come from as deep as common accepted value because of its lower pressure 3.0 GPa than that suggested by Jr. L . Coes. However, according to the fact discovered in this paper that the coesite could be synthesized under a condition of very short time (about 10 s) by the high static pressure after pre-treated of HEMBM, the intermediate phase of -quartz could be transformed into coesite instantaneously by the interaction of an earthquake wave and/or stress. Therefore we suggest some other possible formation mechanisms for coesite in the Earth's crust and show that the coesite in the Earth's crust could record some information about the collision dynamics of plates and an earthquake wave.

Numerical Simulation of Shock Wave Structure in Single Crystal Copper

DENG Xiao-Liang, ZHU Wen-Jun, LUO Jin, HE Hong-Liang, WU Deng-Xue, JING Fu-Qian

2006, 20(2): 172-178 . doi: 10.11858/gywlxb.2006.02.010

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Abstract:
The structure of shock wave in single crystal copper has been studied by means of molecular dynamics (MD) method with a realistic embedded atom potential at initial condition of zero temperature. The simulation results indicate that the after-shock state will evolve to thermodynamic equilibrium state even initial state is zero temperature. By means of local analysis and calculation, time history of the distribution of pressure, particle velocity, strain and kinetic temperature after the shock front were obtained. The pressure, particle velocity, and strain increase and arrive at the stable condition within time period about 1 ps when shock pressure is about 262 GPa. The kinetic temperature always keeps maximum value in shock wave front and the nonzero temperature region broadens behind the shock wave as time passes by. After evolution of a critical time, the particle velocity in the after-shock region reaches a typical Maxwell distribution which means it reaches equilibrium state. The further analysis indicates that local equilibrium is an elemental course when the whole system evolves to thermodynamic equilibrium state.

Study on the Synthesized Black Low-Magnetism Diamond

PENG Fang, ZHANG Mei-Guang, CHEN Chao, WANG Jiang-Hua, SUN Gang, LUO Xiang-Jie

2006, 20(2): 179-182 . doi: 10.11858/gywlxb.2006.02.011

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Abstract:
Based on the testing of the magnetic susceptibility of the raw materials and the final products: graphite, Ni70Mn25Co5, general diamond, black diamond and melting NiMnCoC in the synthesis of diamond and the analyzing of the fracture surface of black diamond and general diamond by the Scanning Electron Microscope, it is found that the magnetism of the synthetic diamond is caused by NiMnCoC inclusions. There are many inclusions in the fracture surface of general diamond, but there are no inclusions in the fracture surface of black diamond, merely many cavities existed. The low magnetism existing in black diamond is from the poor quality and more-cracked diamond caused by higher temperature and lower pressure in the synthesis of diamond. A lot of cracks exit between diamond surface and inclusion. Because the magnetic catalyst inclusions are removed by acids through the cracks during the process of chemical treatment, the black diamond has low magnetism.

Effect of High Pressure Treating Catharanthus Roseus Seeds on Enhancing Content of Vinblastine in the Plant

CHEN Li-Ying, WU Xue-Hua, LIU Xiu-Ru, SU Lei, HONG Shi-Ming, LIANG Heng-Xing, GUO Li

2006, 20(2): 183-188 . doi: 10.11858/gywlxb.2006.02.012

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Abstract:
Three groups of short annual Catharanthus roseus seeds were treated in high pressure nitrogen gas for 4 h at room temperature; the pressure was 10, 20 and 30 MPa, respectively. Other untreated seeds were regarded as a control group (abbreviated to CP). All seeds were planted under same condition. The vegetal character of the Catharanthus roseus was observed in detail and contents of Vinblastine and Vincristine in the plants were detected by HPLC. Experimental results indicated that the contents of Vinblastine increased remarkably and Vincristine tended to increase in the plants of the pressure treated groups in comparison to CP. It is also noticed that distributions of variance of the flowers and ill aftergrowth plants are corresponding approximately to that of the contents of Vinblastine. Mechanism of the effects of pressure treatment was discussed qualitatively.

The Effect of Engraving Force of Projectile on Interior Ballistic Performance of DAVIS Gun

DUAN Ji-Yuan, WANG Yan-Ping, LIU Cang-Li, YU Chuan

2006, 20(2): 189-193 . doi: 10.11858/gywlxb.2006.02.013

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Abstract:
The engraving force of projectile of a DAVIS gun through the way of project and interior ballistics during engraving has been calculated, and its effect on interior ballistic performance has been analyzed. The experiential value for theoretic model was determined, which simplified the calculation, but wih good experimental precision. Our analysis provided a ground for building interior ballistic model and experiment of such gun.

Single-Domain Nanosphere Observation and Ferromagnetic/Antiferromagnetic Coupling of Ni/NiO

LIU Xian-Song, ZHANG Cheng-Wen, ZHOU Sheng-Qiang, YIN Ping, Udi Meridor, Aviad Frydman, Aharon Gedanken

2006, 20(2): 194-201 . doi: 10.11858/gywlxb.2006.02.014

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Abstract:
Magnetic force microscopy (MFM) measurements were performed on monodispersed single-domain nickel nanospheres fabricated by the microwave-assisted (MW) polyol method. As found by MFM, a relevant characteristic of these spheres with a size distribution in the 100~180 nm range is the magnetic stripe domain structure. The obtained highly globular nanostructures of NicoreNiOshell were measured by XRD, TEM, XPS, and EDAX. The ferromagnet/antiferromagnet interface coupling is discussed with the results of VSM and SQUID. The relation of the exchange-coupling field with particles sizes is evaluated.

Structural Design and Experimental Study on Forward Shaped Charge and Explosion-Proof Body for Tandem Warhead

DUAN Jian, YANG Qian-Long, ZHOU Gang, CHU Zhe, TIAN Ya-Jun, ZHANG Ying

2006, 20(2): 202-206 . doi: 10.11858/gywlxb.2006.02.015

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Abstract:
The forward shaped charge's penetrative technology and the two-stage explosion-proof technology are two key technologies in the studies of tandem warhead. Based on theoretic analysis and experimental study, we have analyzed the forward charge's structure and its blast effect on the follow-through penetrator, and conducted a design for the experiments of forward shaped charge penetrating concrete target by using porous aluminum as explosion-proof measure. The experimental results show that the forward charge penetrating concrete target forms a hole of 8.2 and 0.4～0.6 times the size of forward charge's diameter in depth and in diameter, repectively; and porous aluminum explosion-proof body effectively protects the follow-through penetrator being damaged from the forward charge's blast impact.

Study of the Uncertainty of the Ejected Mass Measured by ASAY Foil Method

MA Yun, WANG Xiao-Song, LI Xin-Zhu, HU Shao-Lou, LI Jia-Bo, CHEN Hong, WENG Ji-Dong

2006, 20(2): 207-210 . doi: 10.11858/gywlxb.2006.02.016

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Abstract:
The thin foil Doppler laser interferometry named ASAY foil method that can measure the mass of the ejection was described. The measurement accuracy of ASAY foil method had been tested on a predetermined ejection called Simulated Standard Ejection that a well defined thin layer of aluminium powder was bond on a polished stainless steel plate by vacuum grease. The experimental results show that the relative uncertainty of mass measured by ASAY foil method is less than 50%.

Preparation and Structure Characters of Nano-Powder of Ti1-xCexO2 System

LI Jian, SONG Gong-Bao, WANG Mei-Li, ZHANG Bao-Shu

2006, 20(2): 211-216 . doi: 10.11858/gywlxb.2006.02.017

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Abstract:
The series samples of Ti1-xCexO2 (x=0, 0.01, 0.02, 0.04, 0.06, 0.07 and 0.09) were prepared by Sol-Gel process. The particle sizes, morphologies, solid solution range and phase relations of Ti1-xCexO2 samples were studied by XRD, TEM and HR-TEM. Meanwhile, the Rietveld refinement method was employed to study the effect of Ce doped to crystal structure of TiO2. The results show that the solid solution of Ti1-xCexO2 can be formed by doping of Ce to TiO2, and x=0~0.06. The crystallization size of Ti1-xCexO2 is about 5~10 nm, its average particle size is about 35 nm, and they are uniform.

Charge Release Characterization of PZT95/5 Ferroelectric Ceramics under Tilted Shock Wave Compression

ZHANG Fu-Ping, ZHANG Yi, DU Jin-Mei, WANG Hai-Yan, HE Hong-Liang

2006, 20(2): 217-219 . doi: 10.11858/gywlxb.2006.02.018

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Abstract:
The current waveform of Ferroelectric ceramics PZT95/5 depoling under tilted shock wave compression has been studied. Analytic model was established to analyze the effects of incident angle on the rising time, duration and peak amplitude of the depoling current. Experiments were conducted as well to confirm these effects. Results indicted that with the increasing of incident angle, the depoling current rises with longer time, pulse duration becomes broad and the peak amplitude keeps constant until the waveform decays into triangular form.

Study on the Synthesis of New Energetic Fullerene Derivative

JIN Bo, PENG Ru-Fang, SHU Yuan-Jie, ZHONG Fa-Chun, CHU Shi-Jin

2006, 20(2): 220-224 . doi: 10.11858/gywlxb.2006.02.019

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Abstract:
A new fullerene derivative 1 which contains energy-producing groups was prepared by the Prato reaction, and the reaction conditions affecting the yield of product 1 were investigated. The optimized reaction conditions which afforded 65.8% (based on consumed C60) of product 1 are: molar ratio of C60, 2, 4-dinitrobenzaldehyde and N-methylglycine 1∶2∶6, reaction temperature 95 ℃, reaction time 40 h. The structure of product 1 was characterized by UV-vis, FT-IR, 1H NMR and MS. Further study on the property and application of 1 is under way.

2006 Vol. 20, No. 2

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