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Optimization of the imaginary time step evolution for the Dirac equation

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Science China(physics,Mechanics & Astronomy) 2011年第2期54卷 231-235页

作者： LI FangQiong1,ZHANG Ying2,LIANG HaoZhao2,3.& MENG Jie4.2,5 1Guizhou university for Nationalities,Guiyang 550025,China 2State Key Lab Nuclear physics & Technology,School of physics,{3. university,beijing 100871,China 3.nstitut de Physique Nucle’aire,IN2P3.CNRS and Universite’ Paris-Sud,F-914.6 Orsay Cedex,France 4.chool of physics and Nuclear Energy Engineering,Beihang university,beijing 100191,China 5department of physics,university of Stellenbosch,Stellenbosch,South Africa 1. Guizhou university for Nationalities Guiyang 550025 China2. State Key Lab Nuclear Physics & Technology School of Physics Peking University Beijing 100871 China3. Institut de Physique Nucléaire IN2P3-CNRS and Université Paris-Sud F-91406 Orsay Cedex France4. School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China5. Department of Physics University of Stellenbosch Stellenbosch South Africa

Taking the single neutron levels of 12C in the Fermi sea as examples,the optimization of the imaginary time step(ITS) evolution with the box size and mesh size for the Dirac equation is *** the weakly bound states,in order to reproduce the exact single-particle energies and wave functions,a relatively large box size is *** long as the exact results can be reproduced,the ITS evolution with a smaller box size converges faster,while for both the weakly and deeply bound states,the ITS evolutions are less sensitive to the mesh ***,one can find a parabola relationship between the mesh size and the corresponding critical time step,i.e.,the largest time step to guarantee the convergence,which suggests that the ITS evolution with a larger mesh size allows larger critical time step,and thus can converge faster to the exact *** conclusions are very helpful for optimizing the evolution procedure in the future self-consistent calculations.

关键词： Dirac equation Schrdinger-like equation imaginary time step method convergence

Photorefractive Effect in Poly(N-vinylcarbazole)-Based Composite Sensitised by C_(60)

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Chinese Chemical Letters 1997年第9期8卷 807-810页

作者： Zhi Jie ZHANG Yi Wang CHEN Yuan Kang HE and Hui Ying CHEN(Institute of Polymer Science, College of Chemistry, peking university, beijing, 100871)Zhi Jian CHEN Shu Feng WANG and Qi Huang GONG({3. of {4., Mesoscopic {4. Laboratory, peking U Institute of Polymer Science College of Chemistry Peking University Beijing 100871 China department of physics Mesoscopic Physics Laboratory Peking University Beijing 100871 China

A new PVK-based photorefractive polymer composite sensitized by C60 and doped with a higher content of EO chromophore was prepared. The high optical quality thin-film was formed between two ITOcovered glass electrodes. Two-beam-coupling (2BC) experiment was performed by using a He-Ne laser (at wavelength 63..8nm), and an obvious photorefractive performance was observed. The dependence of two-beamcoupling gain coefficient on the applied poling dc electric field was measured.

关键词： Photorefractive Effect in Poly Based Composite Sensitised by C N-vinylcarbazole Rev

Design of a new dynamical core for global atmospheric models based on some efficient numerical methods

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Science China Mathematics 2004年第z1期47卷 4-21页

作者： WANG Bin, WAN Hui, Jl Zhongzhen, ZHANG Xin, YU Rucong, YU Yongqiang & LIU HongtaoState Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric physics, Chinese Academy of Sciences, beijing 100029, China department of Computational Mathematics, Academy of Mathematics and System Sciences,{3.,{4., China Chinese Acad Sci Inst Atmospher Phys State Key Lab Numer Modeling Atmospher Sci & Geop Beijing 100029 Peoples R China peking Univ Acad Math & Syst Sci Dept Computat Math Beijing 100871 Peoples R China

A careful study on the integral properties of the primitive hydrostatic balance equations for baroclinic atmosphere is carried out, and a new scheme todesign the global adiabatic model of atmospheric dynamics ispresented. This scheme includes a method of weighted equal-areamesh and a fully discrete finite difference method with quadraticand linear conservations for solving the primitive equationsystem. Using this scheme, we established a new dynamical corewith adjustable high resolution acceptable to the availablecomputer capability, which can be very stable without anyfiltering and smoothing. Especially, some important integralproperties are kept unchanged, such as the anti-symmetries of thehorizontal advection operators and the vertical convectionoperator, the mass conservation, the effective energy conservationunder the standard stratification approximation, and so on. Somenumerical tests on the new dynamical core, respectively regardingits global conservations and its integrated performances inclimatic modeling, incorporated with the physical packagesfrom the Community Atmospheric Model Version 2 (CAM2) of NationalCenter for Atmospheric Research (NCAR), are included.

关键词： dynamical core, equal-area mesh, anti-symmetry, effective energy conservation.

Debating about the climate warming

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Progress in Natural Science:Materials International 2006年第1期16卷 1-6页

作者： WANG Shaowu1, LUO Yong2, ZHAO Zongci2, DONG Wenje2 and YANG Bao3.(1.department of Atmospheric Sciences, School of physics, peking university,{3., China 2. Laboratory for Climate Studies, China Meteorological Administration, {4. 100081, China 3. Institute of Cold and Arid Regions Environmental and Engineering, Chinese Academy of Sciences, Lanzhou 73.000, China) [a] department of Atmospheric Sciences School of Physics Peking University Beijing China [b] Laboratory for Climate Studies China Meterological Administration Beijing China [c] Institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou China

Debating about the climate warming is reviewed. Discussions have focused on the validity of the temperature reconstruction for the last millennium made by Mann et al. Arguments against and for the reconstruction are introduced. Temperature reconstructions by other authors are examined, including the one carried out by Wang et al. in 1996. It is concluded that: (1) Ability of reproducing temperature variability of time scale less than 10 a is limited, so no sufficient evidence proves that the 1990s was the warmest decade, and 1998 was the warmest year over the last millennium. (2) All of the temperature reconstructions by different authors demonstrate the occurrence of the MWP (Medieval Warm Period) and LIA (Little Ice Age) in low frequency band of temperature variations, though the peak in the MWP and trough in LIA varies from one reconstruction to the others. Therefore, terms of MWP and LIA can be used in studies of climate change. (3. The warming from 1975 to 2000 was significant, but we do not know if it was the strongest for the last millennium, which needs to be proved by more evidence.

关键词： climate warming MWP LIA the 20th century.

Measurement　of　the　First　Hyperpolarizability　of　Substituted　Ketene　N，S－acetals　by　Hyper－Rayleigh　Scattering　in　Solution

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Chinese Journal of Lasers 1995年第5期B4卷 431-438页

作者： GAO Xingyu CHEN Jingbiao WANG Congfang ZOU Yinghua (department of physics, peking university,{3., China)ZOU Yue FENG Jun LI Jisheng YE Cheng (Institute of Chemistry, Academia Sinica, {4. 100080,China) peking Univ Beijing China

ＭｅａｓｕｒｅｍｅｎｔｏｆｔｈｅＦｉｒｓｔＨｙｐｅｒｐｏｌａｒｉｚａｂｉｌｉｔｙｏｆＳｕｂｓｔｉｔｕｔｅｄＫｅｔｅｎｅＮ，Ｓ－ａｃｅｔａｌｓｂｙＨｙｐｅｒ－ＲａｙｌｅｉｇｈＳｃａｔｔｅｒｉｎｇｉｎＳｏｌｕｔｉｏｎＧＡ... 详细信息

ＭｅａｓｕｒｅｍｅｎｔｏｆｔｈｅＦｉｒｓｔＨｙｐｅｒｐｏｌａｒｉｚａｂｉｌｉｔｙｏｆＳｕｂｓｔｉｔｕｔｅｄＫｅｔｅｎｅＮ，Ｓ－ａｃｅｔａｌｓｂｙＨｙｐｅｒ－ＲａｙｌｅｉｇｈＳｃａｔｔｅｒｉｎｇｉｎＳｏｌｕｔｉｏｎＧＡＯＸｉｎｇｙｕ；ＣＨＥＮＪｉｎｇｂ...

关键词： Hyper-Rayleigh scattering first hyperpolarizability

Nuclear Effect on Gluon Distribution Function and Associate Production of J/Ψ and y with Large P_T in High Energy p-Fe Collision

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Chinese journal of nuclear physics 1995年第3期17卷 205-208页

作者： Zhang Shu~2 He Zhe-min~(1,2) Peng Hong-an~(1,3. Duan Chun-gui~21 CCAST(World Laboratory)P.O.Box 873.,Biejing 1000802 physics department,Hebei Normal {4.,Shijiazhuang,0500163.physics department,peking {4.,beijing 100871 Hebei Normal Univ Shijiazhuang China

With three theoretical models of nuclear effects on gluon distribution functions,the differentialcross sections and the total cross sections for associate production of J/ψ and γ with large P_T in high energyp-Fe co... 详细信息

关键词： Gluon distribution function Nuclear effect J/Ψ production

A DOMINANT DEFECT AT THE Si/SiO_2 INTERFACE IN MOS STRUCTURE

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Science China Mathematics 1989年第12期32卷 1458-1468页

作者：陈开茅卢殿通 department of physics Peking University Institute of Low Energy Nuclear physics of beijing Normal university

The interface defects at the Si/SiO_2 interface in ρ-type silicon (111) MOS structures have been studied by the DLTS method. A dominant defect H_(it),(0.503. at the Si/SiO_2 interface has been found. Its characteristics are (i) the average hole ionization Gibbs free energy △G_p≥0.503.eV; (ii) by changing the gate bias when the distance from Fermi level to the top of Si valence band at the Si/SiO_2 interface is less than △G_p there is still the strong DLTS peak; (iii) its hole apparent activation energy increases with the dectease of the height of semiconductor surface potential barrier; and (iv) its hole capture process causes the multiexponential capacitance transience as a function of pulse width and the H_(it)(0.503. level are very difficult to be fully filled with the holes introduced by thepulst with alimited width. All above show that there is a continuous transition energy band between the energy bands of the covalent crystal silicon and the SiO_2 in the Si/SiO_2 systems formed by thermal oxidation; the dominant defect H_(it)(0.503. is distributed in the transition region, and the distance of H_(it)(0.503. level from the top of the valence band increases with the distance from the silicon surface.

关键词： interface defects MOS structure physics model of Si/SiO_2 interface.

Calculating the Activity Coefficient of Phosphate in Various Diluent by the UNIFAC Method

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Chemical Journal of Chinese Universities 1988年第3期 34-39页

作者： Wang Liya Zhong Yunxiao(department of technical physics,{3., {4.)

This paper extends the UNIFAC method to calculate tne pnospnate-_ diluents systems. The parameters of interaction between (-O)3.P-O and CH2, CCl4., CHCl3. ACH, ACCl, CH-O, H2O etc. are determined with the experimental data of Tri-iso-butylphosphate(TiBp)-diluents and Tri-(2-ethyl)hexylphosphate(TEHP)-diluents systems. These parameters were applied to calculate the activity coefficient of TBP-diluents and TEHP-diluents systems. The result agrees excellently with experimental data.

关键词： UNIFAC method Phosphate Activity coefficients

The research of below-cloud scavenging of rainwater in Guilin City

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Journal of Environmental Sciences 1994年第3期6卷 322-329页

作者： Bai Yuhua Yao Rongkui Li Xin Tang Xiaoyan(The department of technical Physies and The Center of Environmental Science,peking {3.,{4., China)

Sequential samples of single precipitation event were collected by the use of specially de-signed semi-automatic sequential precipitation collector in the spring of 1988 in Guilin City. ThePH value and soluble chemical species such as SO, NO, NH, Ca￣(2+), Mg￣(2+), Na￣+, K`+, F￣- andCl￣- were analyzed. An apparent decrease in the concentration of all ions except H￣+ and NO wasobserved at the initial portion of the events. The relative acidity increased as the event *** concentration of H￣+ was the result of comprehensive actions of all ions. The average scavengingratio of events was calculated and it is found that SO was the major contributor for acid rain inGuilin and Ca￣(2+) was the important neutralizer.

关键词： acid rain, sequential sample below-cloud scavenging precipitation event.