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The relativistic consistent angular-momentum projected shell model study of the N=Z nucleus ^(52)Fe

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Science china(physics,Mechanics & Astronomy) 2009年第10期52卷 1471-1476页

作者： LI YanSong1,2 & LONG GuiLu1,2 1 department of physics,tsinghua university,beijing 100084,china 2 center of Nuclear Theory,National Laboratory of Heavy Ion Accelerator of Lanzhou,Lanzhou 730000,china department of physics Tsinghua University Beijing China center of Nuclear Theory National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

The relativistic consistent angular-momentum projected shell model(ReCAPS) is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus *** model calculations show a reasonably good agreement with the *** backbending at 12+ is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.

关键词： ReCAPS relativistic mean field angular-momentum projection method 52Fe neutron-proton interaction

A measure for spatial heterogeneity of vegetation in the center of Inner Mongolia

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Progress in Natural Science:Materials International 2008年第3期18卷 289-295页

作者： Baimin Songa,b, Daming Huangc,d, Renqing Wanga, Shiyomi Masae d, Fei Xua, Wei Wanga, Gaosheng Zhanga, Xianqiang Zhanga, Jian Qiaoe a College of Life Science, Shandong university, Jinan 250100, china b department of Environmental Science and engineering, tsinghua university, beijing 100084, china c Institute of Ecology, department of Biological Sciences and Biotechnology, tsinghua university, beijing 100084, china d Faculty of Science, Ibaraki university, Bunkyo 2-1-1, Mito 310-8512, Japan e department of Chemical engineering, tsinghua university, beijing 100084, china College of Life Science Shandong University Jinan 250100 China department of Environmental Science and engineering Tsinghua University Beijing 100084 China Institute of Ecology Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China Faculty of Science Ibaraki University Bunkyo 2-1-1 Mito 310-8512 Japan department of Chemical engineering Tsinghua University Beijing 100084 China

This study surveyed and analyzed the vegetation heterogeneity in the center of Inner Mongolia (CIM) by a new method based on the beta-binomial distribution for each kind of vegetation. As many as 190 large quadrats of 5 mm 5 mm (representing an area of 50 km 50 km) (referred to as L-quadrats hereafter) were extracted from about an area of 475,000 km2. Each L-quadrat was divided into four small quadrats (S-quadrat) of 2.5 mm 2.5 mm (equivalent to 25 km 25 km) and the frequency of occurrence of each type of vegetation was recorded in each small quadrate. The weighted average heterogeneity from all of the vegetations composing a land- scape provides a measure at landscape level to determine the spatial intricateness of landscape composition. Our results indicated that each vegetation has its own distribution pattern and the degree of heterogeneity is different from one kind of vegetation to the other. The results proved that the beta-binomial distribution can be very useful for analyzing vegetation landscapes.

关键词： Heterogeneity Beta-binomial distribution Frequency Occurrence Inner Mongolia

The effect of hydrogen on the electronic structure of kink in bcc iron

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Science china(Technological Sciences) 2009年第5期52卷 1212-1218页

作者： CHEN LiQun1,QIU ZhengChen1,YU Tao2 & WANG ChongYu2,3,4 1 College of Sciences,Central South university of Forestry and Technology,Changsha 410004,china 2 Central Iron and Steel Research Institute,beijing 100081,china 3.department of physics,tsinghua university,beijing 100084,china 4 International center for Materials physics,Chinese Academy of Sciences,Shenyang 110016,china College of Sciences Central South University of Forestry and Technology Changsha China Central Iron and Steel Research Institute Beijing China department of physics Tsinghua University Beijing China International center for Materials physics Chinese Academy of Sciences Shenyang China

The electronic structures of kinks in the [100](010) and 1/2[111](-110) edge dislocations in bcc iron containing hydrogen are investigated by means of the first-principles DMol method and the discrete variational *** effects of hydrogen on the kinks are *** results show that hydro-gen forms weak bonding states with its neighboring host atoms,and since hydrogen draws charge from its neighboring host atoms,the interactions between most of the host atoms are weakened com-pared with those of the corresponding atomic pairs in the clean *** indicates that the migration of kink,*** motion of dislocation,is easier in the doping hydrogen kink than in the clean kink,which may be the solid solution softening effect resulting from the impurity hydrogen.

关键词： electronic structure dislocation kink impurity

Performance of Polarizers and Coupler in an All Polarization Maintaining Fiber Interferometer

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Chinese Journal of Lasers 2000年第2期9卷 148-154页

作者： CHEN Zhe LIAO Yanbiao HU Yongming LI Xiujian MENG Zhou ( department of Electronic engineering, tsinghua university, beijing 100084, china department of Applied physics, National university of Defense Technology, Changsha 410073, china ) 清华大学北京 100084 国防科学技术大学湖南长沙

It is given mathematical models and analyze the performance of polarizers and coupler in an all polarization maintaining fiber (PMF) Michelson interferometer. The optical coherent signal to noise ratio (CSNR) of the i... 详细信息

关键词： polarization maintaining fiber interferometer optical fiber polarizer optical fiber coupler Jones matrix

Molecular dynamics simulation of kink in 〈100〉 edge dislocation in body centred cubic iron

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Chinese Science Bulletin 2007年第16期52卷 2291-2296页

作者： CHEN LiQun1,2,WANG ChongYu2,3,4 & YU Tao2 1 College of Sciences,Central South university of Forestry & Technology,Changsha 410004,china 2 Central Iron and Steel Research Institute,beijing 100081,china 3.department of physics,tsinghua university,beijing 100084,china 4 International center for Materials physics,Chinese Academy of Sciences,Shenyang 110016,china College of Sciences Central South University of Forestry & Technology Changsha China Central Iron and Steel Research Institute Beijing China department of physics Tsinghua University Beijing China International center for Materials physics Chinese Academy of Sciences Shenyang China

Using the molecular dynamics method,we have constructed two kink models corresponding to the 〈100〉{010} and 〈100〉{011} edge dislocations (EDs) in body centred cubic (bcc) Fe. It is found that the geometric structure of a kink depends on the type of edge dislocation and the structural energies of the atoms sites in the dislocation core region. The formation energies,migration energies and widths of the kinks in different types of EDs are calculated. The results show that formation and migration of the kink in the 〈100〉{010} edge dislocation are difficult. The 〈100〉{011} edge dislocation moves primarily through kink nucleation,rather than kink migration.

关键词：分子动力学边缘位移铁纽结结构

Discovery of a high confidence soft lag from an X-ray flare of Markarian 421

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 224-227页

作者： ZHANG YouHong1,HOU ZhengTian2,SHAO Li3 & ZHANG Peng1 1 department of physics and tsinghua center for astrophysics(THCA),tsinghua university,beijing 100084,china 2 Group of Mathematics and physics,Shangqiu Medical College,Shangqiu 476100,china 3 Max-Planck-Institut für extraterrestrische Physik,Postfach 1312,Garching 85741,Germany department of physics and tsinghua center for astrophysics (THCA) Tsinghua University Beijing China Group of Mathematics and physics Shangqiu Medical College Shangqiu China Max-Planck-Institut für extraterrestrische Physik Garching Germany

We present the X-ray variability properties of the X-ray and TeV bright blazar Mrk 421 with a-60 ks long XMM-Newton observation performed on November 9-10,*** source experienced a pronounced flare,of which the inter-band time lags were determined with a very high confidence *** soft(0.6-0.8 keV) X-ray variations lagged the hard(4-10 keV) ones by 1.09+0.11-0.12 ks,and the soft lag increases with increasing difference in the photon *** energy-dependent soft lags can be well fitted with the difference of the energy-dependent cooling timescales of the relativistic electron distribution responsible for the observed X-ray emission,which constrains the magnetic field strength and Doppler factor of the emitting region to be Bδ 1/3-1.78 Gauss.

关键词： BL Lacertae objects:individual:Mrk-421 galaxies:active radiation mechanisms:non-thermal X-rays:galaxies

Bitstream decoding and SEU-induced failure analysis in SRAM-based FPGAs

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Science china(Information Sciences) 2012年第4期55卷 971-982页

作者： WANG ZhongMing 1,2,YAO ZhiBin 2,GUO HongXia 2 & LV Min 1 1 department of engineering physics,tsinghua university,beijing 100084,china 2 Northwest Institute of Nuclear Technology,Xi'an 710024,china department of engineering physics Tsinghua University Beijing China Northwest Institute of Nuclear Technology Xi’an China

Reconfigurable SRAM-based FPGAs are highly susceptible to radiation induced single-event upsets (SEUs) in space *** bit flip in FPGAs configuration memory may alter user circuit permanently without proper bitstream reparation,which is a completely different phenomenon from upsets in traditional memory *** is important to find the relationship between a programmable resource and corresponding control bit in order to understand the impact of this *** this paper,a method is proposed to decode the bitstream of FPGAs from Xilinx Corporation,and then an analysis program is developed to parse the netlist of a specific design to get the configuration state of occupied programmable logic and *** that,an SEU propagation rule is established according to the resource type to identify critical logic nodes and paths,which could destroy the circuit topological *** decoded relationship is stored in a *** database is queried to get the sensitive bits of a specific *** result can be used to represent the vulnerability of the system and predict the on orbit system failure *** analysis tool was validated through fault injection and accelerator irradiation experiment.

关键词： radiation effect single-event effect single-event upset SRAM-based FPGA fault injection

Local and non-local sources of airborne particulate pollution at beijing——The ratio of Mg/Al as an element tracer for estimating the contributions of mineral aerosols from outside beijing

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Science china Chemistry 2005年第3期48卷 253-264页

作者： HAN Lihui1, ZHUANG Guoshun1,2,3, SUN Yele1 & WANG Zifa3 1. The center for Atmospheric Environmental Study, department of Chemistry, beijing Normal university, beijing 100875, china 2. center for Atmospheric Chemistry Study, department of Environmental Science & engineering, Fudan university, Shanghai 200433, china 3. LAPC/NZC, Institute of Atmospheric physics, CAS, beijing 100029, china The center for Atmospheric Environmental Study Department of Chemistry Beijing Normal University Beijing China center for Atmospheric Chemistry Study Department of Environmental Science & Engineering Fudan University Shanghai China Institute of Atmospheric physics CAS LAPC/NZC Beijing China

A new element tracer technique has firstly been established to estimate the contri-butions of mineral aerosols from both inside and outside beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles （TSP）, 10%―70% of fine particles （PM2.5）, and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside beijing contributed 62% （38%―86%） of the total mineral aerosols in TSP, 69% （52%―90%） in PM10, and 76% （59%―93%） in PM2.5 in spring, and 69% （52%―83%）, 79% （52%―93%）, and 45% （7%―79%） in TSP, PM10, and PM2.5, respectively, in winter, while only20% in summer and autumn. The sources from outside beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in beijing. The contributions from outside Bei-jing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.

关键词： mineral aerosol local sources non-local sources dust storm re-suspended dust element tracer technique.

Optimizing Concurrent Product Development Process Using Genetic Algorithm

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Systems Science and Systems engineering 2000年第4期10卷 503-510页

作者： YAN Ji\|hong,\ WU Cheng CIMS center, department of Automation, tsinghua university, beijing 100084, china

Scheduling concurrent activities is of great significance to shorten development lead time and minimize the cost, a heuristic optimization scheduling approach therefore is proposed for concurrent product development process, in which some uncertain crucial parameters are determined by genetic algorithm (GA). To ensure the optimal concurrent scheduling and the effective utilization of resources along with the fluent delivery of information, some key factors such as time order, information, resources, lead time and overlapping time of activities are taken into account adequately, and the weights of these factors are fixed by GA. In addition, role allocation and feedback revision process are realized in optimization module. The simulation example is a part of a certain product development process, and the results show the feasibility of the algorithm.

关键词： concurrent engineering product development process optimization scheduling