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A phenomenological equation of state for isospin asymmetric nuclear matter

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Science china({1.,Mechanics & Astronomy) 2009年第10期52卷 1494-1505页

作者： CHEN LieWen1.2 1.Department of physics,Shanghai Jiao Tong {1.,Shanghai 200240,china 2 Center of Theoretical Nuclear physics,National Laboratory of Heavy Ion Accelerator,lanzhou 730000,china Department of physics Shanghai Jiao Tong University Shanghai China Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou China

A phenomenological momentum-independent(MID) model is constructed to describe the equation of state(EOS) for isospin asymmetric nuclear matter,especially the density dependence of the nuclear symmetry energy Esym(ρ).This model can reasonably describe the general properties of the EOS for symmetric nuclear matter and the symmetry energy predicted by both the sophisticated isospin and momentum dependent MDI model and the Skyrme-Hartree-Fock *** find that there exists a nicely linear correlation between Ksym and L as well as between J0/K0 and K0,where L and Ksym represent,respectively,the slope and curvature parameters of the symmetry energy at the normal nuclear density ρ0,while K0 and J0 are,respectively,the incompressibility and the third-order derivative parameter of symmetric nuclear matter at ρ*** correlations together with the empirical constraints on K0,L and Esym(ρ0) lead to an estimation of -477 MeV Ksat,2 -241.MeV for the second-order isospin asymmetry expansion coefficient for the incompressibility of asymmetric nuclear matter at the saturation point.

关键词： equation of state of nuclear matter isospin the symmetry energy

The formation and stability of Si_(1.x)C_x alloys in Si implanted with carbon ions

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Chinese Science Bulletin 2001年第3期46卷 200-204页

作者： WANG Yinshu, LI Jinmin, JIN Yunfan, WANG Yutian, SUN Guosheng & LIN Lanying1. Department of physics, Beijing Normal {1., Beijing 1.0875, china 2. Institute of Semiconductors, Chinese Academy of Sciences, Beijing 1.0083. china 3. Institute of modern physics, Chinese Academy of Sciences, lanzhou 730000, china Department of physics Beijing Normal University Beijing China Institute of Semiconductors Chinese Academy of Sciences Beijing China Institute of modern {1. Chinese Academy of Sciences Lanzhou China

Si1.xCx alloys of carbon (C) concentration between 0.6%-1.0% were grown in Si by ion implantation and high temperature annealing. The formation of Si1.xCx alloys under different ion doses and their stability during annealing were studied. If the implanted dose was less than that for amorphizing Si crystals, the implanted C atoms would like to combine with defects produced during implantation and it was difficult to form Si1.xCx alloys after being annealed at 850℃. With the increment of implanted C ion doses, the lattice damage increased and it was easier to form Si1.xCx alloys. But the lattice strain would become saturate and only part of implanted carbon atoms would occupy the substitutional positions to form Si1.xCx alloys as the implanted carbon dose increased to a certain degree. Once Si1.xCx alloys were formed, they were stable at 950℃, but part of their strain would release as the annealing temperature increased to 1.000℃. Stability of the alloys became worse with the increment of carbon

关键词： ion implantation Si1.xCx alloys stability of Si1.xCx alloys.

Shell effect and capture cross sections in the synthesis of superheavy nuclei

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Science china({1.,Mechanics & Astronomy) 2009年第10期52卷 1489-1493页

作者： DU SaiSai1,2,BIAN BaoAn1,2,3.LIU Min1,2,4,FENG ZhaoQing5,6 & ZHANG FengShou1,2,6 1 Key Laboratory of Beam Technology and Material Modification of Ministry of Education,College of Nuclear Science and Technology,Beijing Normal university,Beijing 100875,china 2 Beijing Radiation Center,Beijing 100875,china 3.School of Science,Jiangnan university,Wuxi 214122,china 4 College of physics and Technology,Guangxi Normal university,Guilin 541004,china 5 Institute of modern physics,Chinese Academy of Sciences,lanzhou 730000,china 6 Center of Theoretical Nuclear physics,National Laboratory of Heavy Ion Accelerator of lanzhou,lanzhou 730000,china Key Laboratory of Beam Technology and Material Modification of Ministry of Education College of Nuclear Science and Technology Beijing Normal University Beijing China Beijing Radiation Center Beijing China School of Science Jiangnan University Wuxi China College of physics and Technology Guangxi Normal University Guilin China Institute of modern {1. Chinese Academy of Sciences Lanzhou China Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

The shell effect is included in the improved isospin dependent quantum molecular dynamics model in which the shell correction energy of the system is calculated by using the deformed two-center shell model. A switch function is introduced to connect the shell correction energy of the projectile and the target with that of the compound nucleus during the dynamical fusion process. It is found that the calculated capture cross sections reproduce the experimental data quantitatively at the energy near the Coulomb barrier. The capture cross sections for reaction 3. 80 Br + 82 208 Pb → 1.7 288 X are also calculated and discussed.

关键词： superheavy nuclei transport theory shell effect cross sections

Collision dynamics of He@C_(60)+He@C_(60) at low energies

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Science china({1.,Mechanics & Astronomy) 2008年第7期51卷 765-772页

作者： ZHAO Qiang1.2, ZHANG FengShou1.2,3.& ZHOU HongYu1.2 1.Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Institute of Low Energy Nuclear {1., Beijing Normal university, Beijing 1.0875, china 2 Beijing Radiation Center, Beijing 1.0875, china 3.Center of Theoretical Nuclear {1., National Laboratory of Heavy Ion Accelerator of lanzhou, lanzhou 730000, china Key Laboratory of Beam Technology and Material Modification of Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing China Beijing Radiation Center Beijing China Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

A semi-empirical molecular dynamics model is developed. The central collisions of C60+C60 and He@C60+He@C60 at different incident energies are investigated based on this model. It is found that the dimer structures have been produced at proper incident energies and these fullerene dimers could be formed by a self-assembly of C60 fullerene and He@C60. The He atom has a significant effect at higher incident energy and this embedded He atom can enhance the stability of the dimer structure.

关键词： C60 He@C60 collision molecular dynamics

β-delayed proton decays near the proton drip line

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Science china({1.,Mechanics & Astronomy) 2005年第3期48卷 257-267页

作者： XU Shuwei 1 , LI Zhankui 1 , XIE Yuanxiang 1 , HUANG Wenxue 1 , SHU Nengchuan 2 , CHEN Yongshou 2 , XU Furong 3., WANG Kun 4 , PAN Qiangyan 1 , WANG Xudong 1 , YU Yong 1 & XING Yebing 1 1. Institute of modern physics, Chinese Academy of Sciences, lanzhou 730000,{3. 2. Nuclear physics Department,{3. Institute of Atomic Energy, Beijing 102413.{3. 3. Department of Technical physics, Peking university, Beijing 100871,{3. 4. Shanghai Institute for Nuclear Research, Shanghai 201800,{3. Institute of modern {1. Chinese Academy of Sciences Lanzhou China Nuclear physics Department China Institute of Atomic Energy Beijing China Department of Technical physics Peking University Beijing China Shanghai Institute for Nuclear Research Shanghai China

We briefly reviewed the experimental study on a-delayed proton decays near the proton drip line published by our group during the period of 1.96―2004, namely the first observation of the a-delayed proton decays of 9 new nuclides in the rare-earth region and the new measurements of a-delayed proton decays of 5 nuclides in the mass ～90 region near the N = Z line with the aid of the “p-?” coincidence in combination with a He-jet tape transport system. In the meantime some important experimental technique details were supplemented. The experimental results, including the half -lives, spins, parities, deformations and production reaction cross sections for the 1. nuclei were summarized and compared with the current nuclear-model predictions, and then the following points were represented. (1. The experimental half-lives for 85Mo and 92Rh as well as the predicted “waiting point” nuclei 89Ru and 93.d are 5―1. times longer than the theoretical predictions given by M?ller et al. using a macroscopic-microscopic model. It considerably influences the predictions of the abundances of the nuclides produced in the rp-process. (2) The current-model predictions are not consistent with the experimental assignments of the spins and parities for the proton drip-line nuclei 1.2Ho and 1.8Pm. However, the nuclear potential energy surface (PES) calculated by using a Woods- Saxon-Strutinsky method reproduced the experimental results. (3. The Alice code overestimated the production reaction cross sections of the studied 9 rare-earth nuclei by one order of magnitude or two, while HIVAP code overestimated them by one order of magnitude approximately.

关键词： proton drip line, β-delayed proton decay, He-jet tape transport system, "p-γ" coincidence, spin, parity, deformation, production reaction cross section.

Simulation of energy and water balance in Soil-Vegetation-Atmosphere Transfer system in the mountain area of Heihe River Basin at Hexi Corridor of northwest china

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Science china Earth Sciences 2005年第4期48卷 538-548页

作者： KANG Ersi1. CHENG Guodong1. , SONG Kechao1. JIN Bowen1. , LIU Xiande3.2 3.& WANG Jinye3.1. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, lanzhou 730000, china 2. State Key Laboratory of Frozen Soil Engineering, Chinese Academy of Sciences, lanzhou 730000, china 3. Academy of Water Resources Conservation Forest of Qilian Mountains, Gansu Province, Zhangye 73.000, china Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China State Key Laboratory of Frozen nSoil Engineering Chinese Academy of Sciences Lanzhou China Academy of Water Resources Conservation Forest of Qilian Mountains Gansu Province Zhangye China

In the mountain area of inland Heihe River Basin at Hexi Corridor of northwest china during the vegetation growing season from May to September, the Simultaneous Heat and Water (SHAW) model of Soil-Vegetation-Atmosphere Transfer (SVAT) system is applied to simulating and studying energy and water balance of the soil-residue-plant canopy layers in the Picea crassifolia forest and the grassland by the forest at the shaded slope and the grassland at the sun-facing slope. The simulation of energy balance indicates that net radiation of the grass- land at the sun-facing slope is more than that of the Picea crassifolia forest and the grassland by the forest at the shaded slope. The energy outgoing components are the first latent heat and next sensible heat from the grassland both at the shaded slope and the sun-facing slope, but those at the former are less. The energy outgoing components are the first sensible heat and next latent heat from the Picea crassifolia forest. The composition and distribution of energy in the soil-residue-plant canopy layers in the Picea crassifolia forest and the grassland by the forest at the shaded slope make the soil layer receive less energy, which therefore, especially the forest possesses the energy conditions for soil water conservation. The simulation of water balance indicates that the water loss of the grassland at the sun-facing slope is mainly caused by soil evaporation, while evapotranspiration of the Picea crassifolia forest and the grassland by the forest at the shaded slope is less than that of the grassland at the sun-facing slope. Half of the evapotranspiration of the Picea crassifolia forest and the grassland by the forest at the shaded slope is consumed by transpiration. After precipitation, the soil water storage is increased much more for the Picea crassifolia forest and also more for the grassland by the forest at the shaded slope. Therefore the shaded slope vegetation, especially the forest is favorable for soil water s

关键词： inland rivers, mountain vegetation zone, Soil-Vegetation-Atmosphere Transfer (SVAT) system, energyand water balance, simulation.

Nonlinear local Lyapunov exponent and atmospheric predictability research

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Science china Earth Sciences 2006年第10期49卷 1111-1120页

作者： CHEN Baohua1. LI Jianping1.2 & DING Ruiqiang2 1. College of Atmospheric Sciences, lanzhou university,{1., china 2. State Key Laboratory of Numerical Modeling for Atmospheric Science and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric {3., Chinese Academy of Sciences, Beijing 1.0029, china College of Atmospheric Sciences Lanzhou University Lanzhou China State Key Laboratory of Numerical Modeling for Atmospheric Science and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

Because atmosphere itself is a nonlinear system and there exist some problems using the linearized equations to study the initial error growth, in this paper we try to use the error nonlinear growth theory to discuss its evolution, based on which we first put forward a new concept: nonlinear local Lyapunov exponent. It is quite different from the classic Lyapunov exponent because it may characterize the finite time error local average growth and its value depends on the initial condition, initial error, variables, evolution time, temporal and spatial scales. Based on its definition and the at-mospheric features, we provide a reasonable algorithm to the exponent for the experimental data, obtain the atmospheric initial error growth in finite time and gain the maximal prediction time. Lastly, taking 500 hPa height field as example, we discuss the application of the nonlinear local Lyapunov exponent in the study of atmospheric predictability and get some reliable results: atmospheric predictability has a distinct spatial structure. Overall, predictability shows a zonal distribution. Prediction time achieves the maximum over tropics, the second near the regions of Antarctic, it is also longer next to the Arctic and in subtropics and the mid-latitude the predictability is lowest. Particularly speaking, the average prediction time near the equation is 1. days and the maximum is located in the tropical Indian, Indonesia and the neighborhood, tropical eastern Pacific Ocean, on these regions the prediction time is about two weeks. Antarctic has a higher predictability than the neighboring latitudes and the prediction time is about 9 days. This feature is more obvious on Southern Hemispheric summer. In Arctic, the predictability is also higher than the one over mid-high latitudes but it is not pronounced as in Antarctic. Mid-high latitude of both Hemispheres (3.°S―60°S, 3.°―60°N) have the lowest predictability and the mean prediction time is just 3.4 d. In addition, predictab

关键词： nonlinear, local, Lyapunov exponent, atmospheric predictability, maximal prediction time.

Direct CP violation in hadronic B decays

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Science china({1.,Mechanics & Astronomy) 2006年第3期49卷 357-366页

作者： HONG Bihai1.2 & Lü Caidian3.1. Department of {1., Lishui university, Lishui 3.3.00,china 2. Department of {1., Shanghai Jiaotong university, Shanghai 20003., china 3. Institute of High Energy {1., Beijing 1.0049,china Department of physics Lishui University Lishui China Department of physics Shanghai Jiaotong University Shanghai China Institute of High Energy physics Beijing China

There are different approaches for the hadronic B decay calculations, recently. In this paper, we upgrade three of them, namely factorization, QCD factorization and the perturbative QCD approach based on kT factorization, using new parameters and full wave functions. Although they get similar results for many of the branching ratios, the direct CP asymmetries predicted by them are different, which can be tested by recent experimental measurements of B factories.

关键词： CP violation hadronic B decay factorization.

Three-dimensional decomposition method of global atmospheric circulation

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Science china Earth Sciences 2008年第3期51卷 386-402页

作者： LIU HaiTao1.2,3. HU ShuJuan4, XU Ming5 & CHOU JiFan6,7 1.State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric {1., Chinese Academy of Sciences, Beijing 1.0029, china 2 Graduate university of Chinese Academy of Sciences, Beijing 1.0049, china 3.Beijing Climate Center, Beijing 1.0089, china 4 Department of Mathematics, lanzhou university, lanzhou 730000, china 5 Shanghai Typhoon Institute, Shanghai 20003., china 6 Department of Atmospheric Sciences, lanzhou university, lanzhou 730000, china 7 china Meteorological Administration Training Center, Beijing 1.0089, china State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate university of Chinese Academy of Sciences Beijing China Beijing Climate Center Beijing China Department of Mathematics Lanzhou University Lanzhou China Shanghai Typhoon Institute Shanghai China Department of Atmospheric Sciences Lanzhou University Lanzhou China china Meteorological Administration Training Center Beijing China

By adopting the idea of three-dimensional Walker, Hadley and Rossby stream functions, the global atmospheric circulation can be considered as the sum of three stream functions from a global perspective. Therefore, a m... 详细信息

关键词： three-dimensional decomposition of the global atmospheric circulation generalized Walker Hadley and Rossby stream functions existence and uniqueness vertical motion