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Synthesize TiO_2 microspheres self-assembled from nanorods via hydrothermal treatment

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Science china Chemistry 2007年第2期50卷 175-178页

作者： ZHANG YiBing1,2,FENG XinJian3 & JIANG Lei2,3 1 Shangrao Teachers’ College,Shangrao 334001,china 2 National Center for Nanoscience and Nanotechnology,beijing 100080,china 3 institute of Chemistry,Chinese Academy of Sciences,beijing 100080,china 1. Shangrao Teachers’ College Shangrao 334001 China 2. National Center for Nanoscience and Nanotechnology Beijing 100080 China 3. institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

The TiO2 microspheres were deposited on the glass substrates under certain conditions via hydro-thermal reaction using 0.15 mol·L?1 TiCl3 saturated NaCl aqueous solution adding urea as an additive. The TiO2 is characterized rutile by results of SEM,TEM and XRD techniques,the TiO2 microspheres are large scale assembled from TiO2 nanorods. The affections on the products by the factors of the con-tents of urea being an additive(the key techniques) ,the reaction temperature,the reaction time and the concentration of TiCl3 were studied. The optimum condition was found,and the mechanism of reac-tions was discussed also.

关键词： TiO2 self-assembly nanorods microsphere hydrothermal reaction

MD simulation of the effect of contact area and tip radius on nanoindentation

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Science china(Physics,Mechanics & Astronomy) 2004年第1期47卷 101-112页

作者： CHEN Shangda1,2 & KE Fujiu1,2 1. Department of Applied Physics, beijing University of Aeronautics and Astronautics, beijing 100083, china 2. State Key Laboratory of Non-linear Mechanics (LNM), institute of Mechanics, Chinese Academy of Sciences, beijing 100080, china Correspondence should be addressed to Chen Shangda (email: chensd@***) Received August 27, 2003 1. Department of Applied Physics Beijing University of Aeronautics and Astronautics 100083 Beijing China 2. State Key Laboratory of Non-linear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences 100080 Beijing China

Molecular dynamics simulations of nanoindentation are performed on monocrystal copper. A new contact atoms method is presented for calculating the contact area. Compared with conventional methods, this method can provide the contact area more accurately not only for sink-in but also for pile-up situation. The effect of tip radius on indentation is investigated too. The results indicate that the measured hardness of the material will become higher as the tip radius increases.

关键词： nanoindentation, molecular dynamics, contact area, zero point of penetration depth, nano- hardness.

6-Membered ring intermediates in polymerization of N-carboxyanhydride-L-α-arginine in H_2O

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Science china Chemistry 2009年第8期52卷 1220-1226页

作者： XIN Liang1,REN Jie1,XIANG JunFeng2,YAN Qin1,XIE Yi1,WANG KongJiang1,LAI PingAn3 & BAI YaDuo3 1 institute of Biophysics,Chinese Academy of Sciences,beijing 100101,china 2 beijing National Laboratory for Molecular Sciences(BNLMS),Centre for Molecular Sciences,institute of Chemistry,Chinese Academy of Sciences,beijing 100080,china 3 beijing Entry-Exit Inspection and Quarantine,beijing 100026,china 1. institute of Biophysics Chinese Academy of Sciences Beijing 100101 China 2. beijing National Laboratory for Molecular Sciences (BNLMS) Centre for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China 3. beijing Entry-Exit Inspection and Quarantine Beijing 100026 China

In polymerization of N-carboxyanhydride-L-α-arginine(L-Arg-NCA) in H2O,nucleophilic reaction of guanidine group with the carbonyl group of L-Arg-NCA leads to quick intramolecular rearrangement,yielding a 6-membered ring intermediate 1-amidino-3-amino-2-piperidone,which is either elongated by another L-Arg-NCA yielding arginyl-1-amidino-3-amino-2-piperidone or hydrolyzed to L-α-*** oligoarginines are formed mainly through hydrolysis of *** is a unique pathway in polymerization of L-Arg-NCA with regard to the usual pathway of elongations by reaction of N-carboxyanhydride-L-α-amino acid with L-α-amino acid or oligopeptides.

关键词： N-carboxyanhydride L-Arg-NCA intermediates L-α-arginine polymerization

A one-dimensional heat transfer model of the Antarctic Ice Sheet and modeling of snow temperatures at Dome A, the summit of Antarctic Plateau

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Science china Earth Sciences 2010年第5期53卷 763-772页

作者： CHEN BaiLian1,3, ZHANG RenHe2, SUN ShuFen1, BIAN LinGen2, XIAO CunDe4,2 & ZHANG TingJun5 1 institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china 2 Chinese Academy of Meteorological Sciences, beijing 100081, china 3 Graduate University of Chinese Academy of Sciences, beijing 100049, china 4 Cold and Arid Regions Environmental and Engineering research institute, Chinese Academy of Sciences, Lanzhou 730000, china 5 The National Snow and Ice Data Center, University of Colorado, Boulder, CO 80309-0449, USA 1. institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Chinese Academy of Meteorological Sciences Beijing 100081 China4. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China5. The National Snow and Ice Data Center University of Colorado Boulder CO 80309-0449 USA

A vertical one-dimensional numerical model for heat transferring within the near-surface snow layer of the Antarctic Ice Sheet was developed based on simplified parameterizations of associated physical processes for the atmosphere, radiation, and snow/ice systems. Using the meteorological data of an automatic weather station (AWS) at Dome A (80°22′S, 70°22′E), we applied the model to simulate the seasonal temperature variation within a depth of 20 m. Comparison of modeled results with observed snow temperatures at 4 measurement depths (0.1, 1, 3, 10 m) shows good agreement and consistent seasonal variations. The model results reveal the vertical temperature structure within the near-surface snow layer and its seasonal variance with more details than those by limited measurements. Analyses on the model outputs of the surface energy fluxes show that: 1) the surface energy balance at Dome A is characterized by the compensation between negative net radiation and the positive sensible fluxes, and 2) the sensible heat is on average transported from the atmosphere to the snow, and has an evident increase in spring. The results are considered well representative for the highest interior Antarctic Plateau.

关键词： Antarctic Ice Sheet near-surface layer energy transfer numerical model

Quantitative estimation of the shrub canopy LAI from atmosphere-corrected HJ-1 CCD data in Mu Us Sandland

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Science china Earth Sciences 2010年第S1期53卷 26-33页

The leaf area index(LAI) is an important ecological parameter that characterizes the interface between vegetation canopy and the *** addition,it is used by most process-oriented ecosystem *** paper investigates the potential of HJ-1 CCD data combined with linear spectral unmixing and an inverted geometric-optical model for the retrieval of the shrub LAI in Wushen Banner of Inner Mongolia in the Mu Us ***(Moderate Resolution Atmospheric Radiance and Transmittance Model) was used for atmospheric *** was extracted using the threshold of the normalized difference vegetation index,with which water bodies and farmland were separated,in combination with a vegetation map of the People's Republic of china(1:1000000).Using the geometric-optical model,we derive the per-pixel reflectance as a simple linear combination of two components,namely sunlit background and *** fraction of sunlit background is related to the shrub *** the support of HJ-1 CCD data,we employ linear spectral unmixing to obtain the fraction of sunlit background in an atmospherically corrected HJ *** addition,we use the measured shrub canopy structural parameters for shrub communities to invert the geometric-optical model and retrieve the pixel-based shrub *** total,18 sample plots collected in Wushen Banner of Inner Mongolia are used for *** results of the shrub LAI show good agreement with R2 of 0.817 and a root-mean-squared error of 0.173.

关键词： shrub leaf area index inversion HJ-1 data geometric-optical model MODTRAN Mu Us Sandland

NEW DEVELOPMENT IN DOUBLE GLOW SURFACE ALLOYING technology

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Chinese Journal of Mechanical Engineering 2002年第2期15卷 186-188页

作者： Xu Zhong Liu Xiaoping Li Zhonghou research institute of Surface Engineering, Taiyuan University of technology, Taiyuan 030024, chinaXie Xishan Zhang Xu University of Science and technology beijing *** research institute of Surface Engineering Taiyuan University of Technology Taiyuan 030024 China

Several kinds of special alloys are produced on the surfaces of iron andsteels by using double glow surface alloying technology. Surface Ni-Cr-Mo-Nb alloy, surfaceprecipitation hardening high speed steel and surface p... 详细信息

关键词： Precipitation hardening Alloying Hardness Corrosion resistance

Vibration-Induced Friction Temperature Field Analysis Under Different Working Condition of Heavy Load Bolt

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Journal of Iron and Steel research International 2011年第S1期18卷 641-645页

作者： LIANG Feng-rui,SU Hang,YANG Cai-fu (institute for Structural Materials,Central Iron and Steel research institute,beijing 100081,china) Cent Iron & Steel Res Inst Inst Struct Mat Beijing 100081 Peoples R China

Based on thermal-stress coupling analysis and material properties studies,the vibration-induced friction process of a special used heavy-load bolt has been *** temperature distribution of the bolt has been calculate with heat radiation and heat convection *** a solid lubricant,polytetrafluoroethylene (PTFE) has bee considered to reduce the friction heat *** result shows that,there are very strong heat effect while no lubracant considered,the temperature of the bolt joint increased sharply and up to 700℃,which exceed the allowable temperature range of the *** PTFE lubricant has been applied,the temperature of the bolt joint increased to 260 ℃,and the bolt steel can by applied in this *** results provide important guidance for the bolt structure modification and material selection.

关键词： friction heat temperature field materials phase transition solid lubrication thermal-stress coupling analysis

Climate change tendency and grassland vegetation response during the growth season in Three-River Source Region

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Science china Earth Sciences 2010年第10期53卷 1506-1512页

作者： QIAN Shuan1,FU Yang2 & PAN FeiFei3 1 National Meteorological Center,beijing 100081,china 2 Qinghai Meteorological research institute,Xining 810001,china 3 Department of Geography,University of North Texas,Denton,TX 76203,USA 1. National Meteorological Center Beijing 100081 China2. Qinghai Meteorological Research Institute Xining 810001 China3. Department of Geography University of North Texas Denton TX 76203 USA

Climate change,climate suitablity change for grassland vegetation,and grassland response to climate change during the growth season are studied systematically by using meteorological data of temperature,precipitation,and length of sunlight from 1961 to 2007,NOAA/AVHRR NDVI from 1982 to 2006,and observations of grass height,biomass,and coverage in enclosed grassland from 1994 to *** models are developed to evaluate climate change and the climatic suitability of grassland vegetation *** temperature,accumulative precipitation,and length of sunlight during the growth season increased from 1961 to 2007 at rates of 0.24°C/10 yr,2.32 mm/10 yr,and 2.81 h/10 yr,*** increase rates of ave-rage temperature between April and May,and between June and August are 0.17 and 0.30°C/10 yr;accumulative rainfall between April and May increased at a rate of 2.80 mm/10 yr,and accumulative rainfall between June and August decreased at a rate of 0.38 mm/10 yr;the increase rates of accumulative length of sunlight between April and May,and between June and August are 2.15 and 1.2 h/10 *** climatic suitability of grassland vegetation growth showed an increasing trend,and the increase rate between April and May is greater than that between June and *** NDVI observations from 1982 to 2006 and measurements of grass height,dry biomass,and coverage from 1994 to 2006 show that the climate change has resulted in an increase in plant productivity of the grassland in Three-River Source *** some protection measures are taken as soon as possible,the deteriorated grassland in Three-River Source Region can recover.

关键词： climate change climate suitability change grassland vegetation Three-River Source Region

Two special topics on the avian influenza virus and on epigenetics,have drawn much attention

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Science china(Life Sciences) 2010年第12期53卷 1483-1484页

作者： HU YongLin institute of Biophysics,Chinese Academy of Sciences,beijing 100101,china 1. institute of Biophysics Chinese Academy of Sciences Beijing 100101 China

Several excellent well-organized reviews and research papers on two special topics, "The challenges of avian influenza virus: mechanism, epidemiology, and control" and "Molecular

关键词： APOBEC gene Two special topics on the avian influenza virus and on epigenetics,have drawn much attention