高压物理学报

Molecular Analysis of Stable Mutagenesis Rice Cultivar Induced by High Hydrostatic Pressure

SHEN Si-Le, XU Shi-Ping, WENG Ke-Nan, TAN Mei, ZHANG Jian-Feng, LONG Guo-Hui, JIA Xiao-Peng, CHI Yuan-Bin, LIU Bao, ZOU Guang-Tian

2004, 18(4): 289-294 . doi: 10.11858/gywlxb.2004.04.001

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Abstract:
By using high hydrostatic pressure treatment, two genetically stable rice lines were obtained from the japonica rice cultivar Bijing 38. Mutant 1 is characterized by its lower segregation frequency and 20 d less of maturation period than the original cultivar. Mutant 2 is characterized by its significantly increased height, increased tillering efficiency and elongated kernels which is similar to what has been seen for indica rice. ISSR and RAPD analyses of these two mutants and the original cultivar revealed that there exists significant genetic variation between the two mutants and the original cultivar, each with 28.57% and 45.98% polymorphic bands respectively. The genetic diversity in Mutant 2 is significantly higher than in Mutant 1. ISSR analysis indicated that the mean absolute distance coefficient between the original cultivar and the Mutant 1 is 0.030 3, while that between the original cultivar and the Mutant 2 is 0.261 3. RAPD analysis demonstrated that the mean absolute distance coefficient between the original cultivar and the Mutant 1 is 0.084 5, while that between the original cultivar and the Mutant 2 is 0.416 7. These studies have provided strong evidence that high hydrostatic pressure could induce mutagenesis during seed germination and the phenotypes, and genetic traits can be stably passed on to the progeny. This is the first time we have shown at molecular level that treatment by high hydrostatic pressure can induce genetically stable mutations in higher plants. In addition to a variety of chemical and X-ray mutagenic methods, high hydrostatic pressure might as well be proven as another efficient method for mutagenesis.

Numerical Simulation of the Instability of the Jelly Surfaces under the Imploding Drives

BAI Jing-Song, LI Ping, CHEN Sen-Hua, LIAO Hai-Dong, YANG Li-Bing, JIANG Yang

2004, 18(4): 295-301 . doi: 10.11858/gywlxb.2004.04.002

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Abstract:
In this paper, we applied the high-resolution compressible multi-fluid PPM method to simulation of the instability of the jelly surfaces under the imploding drives. The outer and the inner surfaces of the jelly are set initially by model 10, 1 mm in top-top and top-bottom disturbance amplitude. Shape, position, velocity and acceleration of the outer and the inner surfaces of the jelly computational results are given. The numerical images are in excellent agreement with the basic physical phenomena.

A Theoretical Study on the Penetration of Rocks Struck by Rigid Projectiles

WEN He-Ming, XU Hai-Bin

2004, 18(4): 302-308 . doi: 10.11858/gywlxb.2004.04.003

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Abstract:
Rocks as natural building materials have been widely used in protective engineering and military fortification/installations. Hence, it is of great significance to carry out studies on the penetration of rock targets by projectiles. This paper contains two parts. The first part is an overview of the previous work with emphasis being placed on the formulas for the depth of penetration; the second part is a further development of the penetration model proposed by Wen by modifying the shear strength (Y) which has been found to be a function of both projectile diameter and target unconfined compressive strength based on the experimental observations. It is shown that the model correlates well with the penetration data for the limestone targets impacted by ogival-nosed projectiles.

Subsolidus Phase Relation and Crystal Structure in the Pr1-xBa2-yCax+yCu3O7 System

SONG Gong-Bao, LIANG Jing-Kui, RAO Guang-Hui

2004, 18(4): 309-314 . doi: 10.11858/gywlxb.2004.04.004

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Abstract:
Subsolidus phase relation and crystal structure in the Pr1-xBa2-yCax+yCu3O7 system were studied by X-ray diffraction combined with Rietveld structure refinement. The results indicate that all of the Pr1-xBa2-yCax+yCu3O7 (y=0) samples contain a BaCuO2 phase besides the Pr123 (PrBa2Cu3O7) phase under 950 ℃ in the air. Furthermore, the content of the BaCuO2 phase increases with increasing Ca content. The samples of Pr1-xBa2-yCax+yCu3O7 (x=0) (y=0.1, 0.2, 0.3, 0.4) contain only one phase, Pr123, except for the sample with y=0.5 which contains three phases, Pr123, Ca2CuO3 and Pr4Ca10Cu24O41. Otherwise, the Pr123 structure takes place the orthorhombic-tetragonal transition in the Pr1-xBa2-yCax+yCu3O7 (x=0) system (y=0.1, 0.2, 0.3, 0.4) with increasing Ca ion content. The structure of the Pr1-xBa2-yCax+yCu3O7 (x=0) samples with y=0.1 and 0.2 is orthorhombic. The lattice parameters are a=0.390 33(4)~0.389 36(1) nm, b=0.389 53(4)~0.387 73(1) nm, c=1.173 38(4)~1.168 20(2) nm; The structure of the Pr1-xBa2-yCax+yCu3O7 (x=0) samples with x=0.3 and 0.4 is tetragonal. The lattice parameters are a=b=0.387 80(0), 0.387 67(0) nm, c=1.166 00(2), 1.165 20 (2) nm. In the Pr123 structure, Ba ions could be replaced by Pr ions, but could not be replaced by Ca ions. Ca ions partially occupy the sites of Pr ions. The ionic radius plays a more important role than the chemical properties in the mutual substitution of Pr, Ba and Ca ions in the Pr123 structure of the Pr1-xBa2-yCax+yCu3O7. The highest content of Ca ions in the Pr1-xBa2-yCax+yCu3O7 system is x=0, y=0.4 under 950 ℃ in air.

Experimental Study on Hypervelocity Flyer Driven by Strong Detonation at Low Vacuum Conditions

WEN Shang-Gang, ZHAO Feng, SUN Cheng-Wei, DENG Wen-Rong, ZHANG Zhen-Tao, PANG Yong, HUANG Wen-Bin, ZHANG Xiao-Lin

2004, 18(4): 315-318 . doi: 10.11858/gywlxb.2004.04.005

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Abstract:
The problem of accelerating metallic flyers to ultra-high speed by multi-stage detonation system at low vacuum conditions is studied in this paper by means of X-rays photography and electrical-pins technique. The pictures of the secondary flyer impacting static target at different time are obtained. The experimental results show that the secondary flyer accelerated by multi-stage detonation system at low vacuum conditions has an advantage of high velocity and good planarity.

Molecular Dynamic Study of Liquid Nitromethane under High-Pressure

LIU Hong, WEI Dong-Qing, ZHAO Ji-Jun, GUO Yong-Xin, GONG Zi-Zheng

2004, 18(4): 319-327 . doi: 10.11858/gywlxb.2004.04.006

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Abstract:
The thermodynamic properties of liquid nitromethane under high-pressure have been determined using molecular dynamic (MD) simulations based on classical empirical potentials and first-principles Car-Parrinello method (CPMD). Classical MD simulations were carried out to study the structural and thermodynamics properties of nitromethane under high pressure, and the theoretical Hugoniot was obtained up to 14.2 GPa. For some thermodynamic functions, such as total energy, particle velocity, the classical MD simulations agree well with experimental results. However, it predicts a higher Hugoniot pressure at given density. The CPMD simulations were performed at several selected densities. The radial pair correlation functions, velocity auto-correlation functions, vibration spectra, and other thermodynamic properties have been obtained and compared with the results of classical MD. The careful analysis of the pair correlation functions reveals that the short-range part of the classical potential may be too stiff. There are substantial differences for pair correlation functions between CPMD and classical simulations, while such difference can be attributed as quantum effects. The vibration spectra of liquid nitromethane were obtained from CPMD simulations at ambient conditions and at high pressure. The pressure-induced shifts of vibrations to high frequency predicted by CPMD are consistent with the experimental observation.

Research on Dynamic Compressive Testing and Mechanical Properties of Silicon Rubber

ZHAO Xi-Jin, LU Fang-Yun, LIN Yu-Liang

2004, 18(4): 328-332 . doi: 10.11858/gywlxb.2004.04.007

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Abstract:
By use of split Hopkinson pressure bars (SHPB) technique, a kind of silicon rubber is investigated for understanding its dynamic constitutive behaviors at high strain rates. Experimental results show that silicon rubber is strain-rate sensitive. It shows viscoelastic characteristics at room temperature and high strain rates. Pulse shaping technique is utilized to ensure the dynamic stress equilibrium in the specimen and to obtain a constant strain rate. Quartz crystal is used to monitor the stress equilibrium and to measure the weak signal in the experiments of silicon rubber.

Self-Consistent Field Calculation of Electron Pressure for Dense Plasmas with Medium-Low Temperature

ZHU Xi-Rui, MENG Xu-Jun

2004, 18(4): 333-338 . doi: 10.11858/gywlxb.2004.04.008

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Abstract:
Criterion for determining free electrons in general SCF average atomic model is revised to describe well the existence of the potential in condensed matter, and, partial wave and Fermi-Dirac statistics are employed for dealing with the resonant electrons and free electrons, individually. The electron pressure is acquired by taking into account the contribution of the resonant states and that of exchange and Coulomb correlations among electrons. The electron pressures for Ni and Cu at zero-temperature are calculated and compared with experiments. Applicability of the model is shown via calculations of pressure for Fe and Pb at definite low temperature and some densities.

Magnetic Behavior of Oxygen-Doped T-R2CuO4 (R=Nd~Tm) at Low Temperature

WU Yun-Long, XIONG Yu-Feng, DAI Wen, LI Ke-Qiang, YAO Yu-Shu, JIN Duo

2004, 18(4): 339-344 . doi: 10.11858/gywlxb.2004.04.009

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Abstract:
The weak ferromagnetic behavior arises from the size effects, which gives rise to the distortion of the T-R2CuO4 structure. In this paper, we study magnetic properties on rare-earth cuprates, R2CuO4 (R=Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Tm), synthesized under high oxygen pressure (6 GPa) at elevated-temperature. The magnetic susceptibility measurements show a new weak-magnetic component near a characteristic temperature of 28 K. Appearances of the low temperature weak-magnetism are independent of the rare-earth components and are a common behavior of all oxygen-doped T-R2CuO4 cuprates. We argue that (1) the weak ferromagnetic behavior occurred near 28 K couldn't be attributed to the size effects, but to the formation of ferromagnetic clusters in CuO2 planes caused by the oxygendoping under high pressure; (2) superconductivity and weak ferromagnetism seem to be exclusive in T-R2CuO4 compounds, i. e., the ferromagnetic clusters in CuO2 planes seems to be incompatible with superconductivity in these system.

An Investigation on the Entropy Argument in Detonation Models

HU Shao-Ming, LI Chen-Fang

2004, 18(4): 345-352 . doi: 10.11858/gywlxb.2004.04.010

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Abstract:
Detonation science has been annoyed for a long time with the argument that the entropy has a minimum at the process end of detonation models. Neglecting thermodynamics, Newton mechanics that is invariant for the substitution t-t may create thermodynamic mistake in describing detonation phenomena. The order assumption in CJ and ZND models, which considers all particles of detonation products march orderly in one direction, implies low entropy and thermodynamic non-equilibrium. Overstating CJ and ZND model, or even treating them as the objective reality of detonation process itself hinders the development of detonation science.

Chemical Reaction of CuO-Al System in Preparation of Al2O3/Cu Composite

WANG Wu-Xiao, JIE Wan-Qi, YUAN Sen

2004, 18(4): 353-358 . doi: 10.11858/gywlxb.2004.04.011

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Abstract:
Chemical reaction in CuO-Al pre-fabricated blocks is controlled at different temperatures. Thermal analysis curves were determined and X-ray diffraction was used to carry out phase analysis of samples after their reactions, whereby the reaction temperature for producing heat explosion and reaction products at different temperatures were obtained. The results indicate that as the medium temperature rises, three different regions of reaction in the CuO-Al system can be classified. When the temperature is less than 1 200 K, there is no chemical reaction; when the temperature is in the range 1 200~1 437 K, a partial chemical reaction takes place whose products are Cu2O, CuAlO2 and Al2O3; when the temperature is over 1 473 K, chemical reaction occurs in the CuO-Al system and the reaction products are Cu and Al2O3. It is in this latter region that thermal explosion is occurs readily.

Analysis of Graphite-Hexagonal Boron Nitride (g-hBN) Micro-Crystal Mixture Treated under High-Pressure and High-Temperature

LUO Xiang-Jie, LUO Bo-Cheng, PENG Fang, CHEN Hao, DING Li-Ye

2004, 18(4): 359-363 . doi: 10.11858/gywlxb.2004.04.012

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Abstract:
For further research of the regularity of B-C-N material prepared by ball-milling method, the micro-crystal mixture of graphite-hexagonal boron nitride (g-hBN) is heat-treated under the pressure of 4.5~5.8 GPa and the temperature of 800 ℃~1 300 ℃. XRD, XPS and FT-IR analysis of the heattreated products shows: at 4.5 GPa and 800 ℃, there is partial crystallization of hexagonal boron nitride (hBN) in samples, but the graphite keeps the status of micro-crystallization; and at 1 300 ℃, samples not only have crystallization of hBN but also have ternary compound of B-C-N, which is analogous to graphite structure. We considered that the new compound was approximate to BC3N when we had compared with correlative information of studies. When the pressure is up to 5.8 GPa and the temperature stays at 1 300 ℃, the changes of result are less.

Simulation of Magnetohydrodynamics for Plasma Jetting on Wire Pinch

WANG Gang-Hua, HU Xi-Jing, SUN Cheng-Wei

2004, 18(4): 364-367 . doi: 10.11858/gywlxb.2004.04.013

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Abstract:
We have worked out one dimensional double region MHD programs for Z-pinch simulation. One of our calculated results of tungsten load has been discussed in the article. The dynamic phenomenon of double wire pinch is presented. The current distribution between the two liners after collision was given. According to our simulation results, 120 GW of X-ray power and 1.0 kJ of X-ray energy are produced in the pinch.

Raman Spectroscopic Studies on Methanol as Pressure Gauge

QIAO Er-Wei, ZHENG Hai-Fei, SUN Qiang

2004, 18(4): 368-373 . doi: 10.11858/gywlxb.2004.04.014

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Abstract:
This paper mainly studies Raman spectroscopy of CH stretching vibrational mode of methanol at 2 835 cm-1 from 169.2 up to 713.8 MPa under the temperature of 301 K using cubic zirconium oxide Anvil Cell. The result shows that methanol is stable at the experimental pressure, and the Raman shift of methanol at 2 835 cm-1 shows a linear dependence with pressure. The correlation between pressure and frequency shift of the 2 835 cm-1 Raman line of methanol is described by p= -3.508 9[(p)2 835]2+135.17 (p)2 835+54.397, where 0.1

Research on Raman Spectra of Water as a Pressure Gauge at High Pressure and Room Temperature

LI Min, ZHENG Hai-Fei

2004, 18(4): 374-378 . doi: 10.11858/gywlxb.2004.04.015

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Abstract:
This paper has discussed the reliability of the Raman spectra of water as a pressure gauge for the hydrothermal diamond anvil cell (HDAC) at pressures of 39~1 150 MPa and a temperature of 26 ℃. The results show a linear relation between pressure and the frequency of the fitted peak: p (MPa)=32.9(p)3 244+200.7 (3 215 cm-1 3 2443 244 cm-1).

Effect of High Pressure Nitrogen Gas Treatments of Mini-Tomato Seeds on Its Growth Characteristics

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

2004, 18(4): 379-384 . doi: 10.11858/gywlxb.2004.04.016

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Abstract:
In this work, mini-tomato seeds (Red Cherry) were separated random into four groups, three of them pretreated by 10, 20 and 30 MPa high pressure nitrogen gas for 4 h respectively, and the untreated one as a comparison group (abbreviated to CP). All seeds were planted under same conditions. Through observing and comparing these plants during the whole life period, 33 chosen random from each group, we learned some effects of the high pressure treatment on its growth characteristics. Additionally, we tested fifteen kinds of nutrition contents in tomato fruits. Outcomes: In contrast with CP, germination stage, seedling stage and flowering stage of the treated groups were shorten. The treated groups suffered lower disease death rate than CP. Furthermore three abnormally high plants occurred in the treated groups, one in 20 MPa group and two in 30 MPa. Nevertheless, no markable differences were found in the average height and average caudexes diameter between the groups, as well as in average fruit yield and the nutrition contents.

2004 Vol. 18, No. 4

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