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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 university, beijing 100875, china 2. Institute of Semiconductors, Chinese Academy of sciences, beijing 100083. china 3. Institute of Modern Physics, Chinese Academy of sciences, Lanzhou 73.000, china department of Physics Beijing Normal University Beijing China Institute of Semiconductors Chinese Academy of Sciences Beijing China Institute of Modern Physics 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.

The onset and advance of the Asian summer monsoon

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Science Bulletin 2006年第1期51卷 80-88页

作者： Lü Junmei1,2,4, ZHANG Qingyun1, TAO Shiyan1 & JU Jianhua3.1. State Key Laboratory of Numerical Modeling for Atmospheric Sci- ences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of sciences, beijing 100029, china 2. {3. of Atmospheric sciences, Yunnan university, Kunming 650091, china 3. china Meteorological Administration Training Centre, beijing 100081, china 4. Graduate school of Chinese Academy of sciences, beijing 10003., china State 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 Atmospheric sciences Yunnan University Kunming 650091 China Graduate school of Chinese Academy of sciences Beijing 100039 China china Meteorological Administration Training Centre Beijing 100081 China

Based on the daily outgoing longwave radiation (OLR) data from National Oceanic and At- mospheric Administration (NOAA) satellites, the Cli- mate Prediction Center’s merged analysis of pre- cipitation (CMAP) data and the National Centers for environmental Prediction/National Center for At- mospheric Research (NCEP/NCAR) reanalysis dataset, the mean intraseasonal variability of the Asian summer monsoon (ASM) is investigated by using power spectrum analysis, band-pass filter, and diagnostic analyses. The processes of the onset and advance of monsoon over the southern part of Indo- china Peninsula, the east coast of Bay of Bengal, the South china Sea and the Indian subcontinent are explored. It is found that there is an abrupt change in OLR, precipitation and zonal wind during the onset and advance of the ASM. It is also indicated that the southern part of Indochina Peninsula and the adja- cent Andaman Sea is the region where the earliest onset of the ASM occurs in the 2nd pentad of May.

关键词： Asian summer monsoon intraseasonal variability onset advance.

The Self-assembling and Application of Inorganic Anti-bacterial Material Made of Natural Nanoporous Carrier

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Journal of Wuhan university of Technology(Materials Science) 2008年第6期23卷 771-774页

作者：孙春宝 school of Civil and environmental Engineering University of Science and Technology Beijing

The inorganic antimicrobial material was inhibited to the microbes with the added metal ion,*** primary wet product carrying 5%-10% zinc ion was generated under the following conditions：temperature was 95 ℃,solution zinc concentration was 1.2-2.0 mol/L,and the ratio of Zn solution to zeolite weight was 5：*** final stable product was manufactured after baking in an oven for 1-3.h at the temperature of 500-900 ℃.The baked material was tested for its disinfection effectiveness and coloring effect when mixed with paint *** on the final batch of tests,the zinc content of this anti-microbial product was further optimized.

关键词： inorganic antimicrobial nanoporous material antibacterial coating zeolite self-assembling

CONVERGENCE OF CHORIN-MARSDEN FOR MULA FOR THENAVIER-STOKES EQUATIONS ON CONVEX DOMAINS

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Journal of Computational Mathematics 1999年第1期17卷 73-88页

作者： Lung-an Ying(Research institute for Mathematical sciences, Kyoto university, Japan department of Mathematics,{3., beijing 100871, china) peking Univ Dept Math Beijing 100871 Peoples R China Kyoto Univ Math Sci Res Inst Kyoto Japan

We prove the convergence of the Chorin-Marsden product formula for solving the initial-boundary value problems of the Navier-Stokes equations on convex domains. As a particular case we consider the case of the half pl... 详细信息

关键词： Navier Stokes equation vortex method fractional step method convergence

Morita contexts on the Hopf algebroid

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Science china Mathematics 2005年第7期48卷 958-971页

作者： YIN Yanmin school of Mathematical sciences, peking university, {3. 100871, china department of Mathematics, Shandong Institute of Architecture and Engineering, Jinan 250101, china 1. school of Mathematical sciences Peking University 100871 Beijing China 2. department of Mathematics Shandong Institute of Architecture and Engineering 250101 Jinan China

We generalize the Morita theory to the Hopf algebroid and give the characterization of the surjectivity of one of the Morita context maps.

关键词： comodule algebra, generalized smash product, Morita context.

A trust region algorithm for bilevel programing problems

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Chinese Science Bulletin 1998年第10期43卷 820-824页

作者： LIU Guoshan 1, HAN Jiye 2 and WANG Shouyang 3.1. department of Mathematics, beijing Normal university, beijing 100875, china 2. Institute of Applied Mathematics, Chinese Academy of sciences, beijing 100080, china 3. Institute of Systems Science, Chi department of Mathematics Beijing Normal University Beijing China Institute of Applied Mathematics Chinese Academy of Sciences Beijing China Institute of Systems Science Chinese Academy of Sciences Beijing China

A trust region algorithm is proposed for solving bilevel programming problems where the lower level programming problem is a strongly convex programming problem with linear constraints. This algorithm is based on a tr... 详细信息

关键词： bilevel programming problem trust region algorithm global convergence.

Abrupt climate change and collapse of ancient civilizations at 2200BC-2000BC

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Progress in Natural Science:Materials International 2005年第10期15卷 46-52页

作者： WANG Shaowu (department of Atmospheric Science, school of Physics, peking university, {3. 100871, china) department of Atmospheric Science School of Physics Peking University Beijing 100871 China

Plentiful evidence of historical, archaeological and palaeoclimatic studies proved that an abrupt change from wetter to drier climate occurred over the Nile Valley,the Mesopotamia, the Indus Valley and Huanghe River Valley at 2200BC-2000BC. The abrupt change was developed based on the general lowering of temperature in the middle latitudes, and was a strong cold event since the beginning of the Megathermal (8.5-3.0 kaBP). Collapse of Nile civilization appeared at the First Intermediate Period (2181BC-2040BC). Civilization of Mesopotamia began collapse following the disintegration of Akkadian Empire. This process lasted to the foundation of Babylon Kingdom from 2200BC to 1900BC. Indus civilization abruptly fell off at 1800BC. A widespread alternation of archaeological cultures happened in china at ca. 2000BC except only in its central part. Longsheng culture was replaced by the Erlitou culture, which is now acknowledged in china as Xia Culture. Foundation of Xia Dynasty at 2070BC opened a new chapter in the development of Chinese civilization. Studies indicated that abrupt climate change may be caused by the weakening of the Thermohaline Circulation (THC).

关键词： 2200BC-2000BC abrupt climate change collapse of ancient civilization.

Pretreatment of Chrysotile With Rare Earth Compounds Lowered Its Cytotoxicity by Lessening Surface Charges

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Biomedical and environmental sciences 1998年第2期11卷 125-132页

作者： FAN JING-GUANG WANG QI-EN LIU SHI-JIE WU WEI-DONG JIA GUANG AND ZHOU LI-LI(National Institute for occupational Safety and health, Ministry of Labour, beijing 100029, {3. department of occupational health, school of Public health, beijing Medical Univers Minist Labor Natl Inst Occupat Safety & Hlth Beijing 100029 Peoples R China beijing Med Univ Sch Publ Hlth Dept Occupat Hlth Beijing 100083 Peoples R China Natl Sports Med Inst Beijing 100029 Peoples R China

Pathological effects of asbestos are probably dependent on the special surface properties of the fibers, such as surface charge, surface metal ions. The present study was designed to determine whether the pretreatment of chrysotile asbestos fibers (CAF) with rare earth compounds (REC) solution can reduce their pathogenicity. The results showed that REC-pretreated CAF induced less nitrogen oxide (NO) production by alveolar macrophages (AM). In addition, the pretreatment lowered the capacity of hemolysis and the methylene blue (MB) adsorption of the native CAF. These findings suggested that the pretreatment of CAF with REC solution reduced the in vitro toxicity of CAF by lessening its surface charges. Nevertheless, the pathogenicity and the carcinogenicity of REC-pretreated CAF in vivo remain to be investigated.

关键词： Br Pretreatment of Chrysotile With Rare Earth Compounds Lowered Its Cytotoxicity by Lessening Surface Charges

Fluxes of NH_3.and HNO_3.over heathland in the Netherlands:implications for chemical interactions

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Journal of environmental sciences 1997年第1期9卷 49-58页

作者： Zhang Yuanhang Center of environmental sciences,peking {3.,beijing 100871,china Center of environmental sciences Peking University Beijing 100871 China

The surface exchange of NH_3.and HNO_3.gases over heathland was measured with the aerodynamic gradient method in Leende,the Netherlands during April 25 and May 9,*** to reactions in the system NH_3.HNO_3.and NH_4NO_3.the NH_3.deposition flux is overestimated,while HNO_3.shows apparent emission fluxes mostly during the field *** reveal that NH_3.gradients are influenced slightly by HNO_3.and the HNO_3.gradients are strongly controlled by the NH_3.A clear relationship between NH_3.and HNO_3.gradient is suggested by the Leende experiment. Before the late afternoon,NH_3.deposition gradients will cause HNO_3.upward gradients,meanwhile the NH_3.gradients themselves will become *** the HNO_3.upward gradient reaches maxi- mum,the NH_3.deposition gradients will be enlarged or the emission gradients depressed,while the HNO_3.upward gradients become smaller.

关键词： dry deposition ammonia nitric acid equilibrium,fluxes.