检索结果-南通市图书馆

Science china Chemistry 2009年第8期52卷 1216-1219页

作者： WANG NaiXing1,2.& TANG XinLiang1,3.1 Technical institute of {2. and Chemistry,Chinese Academy of Sciences,beijing 100080,{3. 2.College of Chemistry and Chemical Engineering,Graduate University of Chinese Academy of Sciences,beijing 10004.,{3. 3.School of Chemical Engineering and Environment,beijing institute of Technology,beijing 100081,{3. 1. Technical institute of physics and Chemistry Chinese Academy of Sciences Beijing 100080 China 2. College of Chemistry and Chemical Engineering Graduate University of Chinese Academy of Sciences Beijing 100049 China 3. School of Chemical Engineering and Environment Beijing Institute of Technology Beijing 100081 China

R-Enantiomer of the β-receptor antagonist N-[3.acetyl-4.(2.hydroxy-3.isopropylamino-propoxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient,convenient and practical synthetic *** product was detected by 1H NMR,13. NMR,and MS,and the enatiomeric excess was determined by chiral HPLC analysis using a chiracel AD-H column.

关键词： chiral synthesis enantioselectivity enatiomeric excess chiral HPLC analysis

Study on growth and properties of novel γ-LiAlO_2.substrate

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2006年第2期49卷 188-193页

作者： ZOU Jun1,2. ZHOU Shengming1, XU Jun1 & ZHANG Rong3.1. Shanghai institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 2.1800, {2. 2. Graduate School of Chinese Academy of Sciences, beijing 10003., {2. 3. Laboratory of Solid State Microstructures and Department of {4., Nanjing University, Nanjing 2.0093. {2. 1. Shanghai institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China 2. Graduate School of Chinese Academy of Sciences Beijing 100039 China 3. Laboratory of Solid State Microstructures and Department of physics Nanjing University Nanjing 210093 China

Transparent γ-LiAlO2.single crystal has been grown by Temperature Gradient technique. The surface of the wafer annealed in O2.atmosphere at 1100°C for 70 h became opaque and Li-poor phase (LiAl5O8); while, that annealed in Li-rich atmosphere kept transparent and smooth. The full-width at half maximum value dropped to 3. arcsecs when the wafer was annealed in Li-rich atmosphere. That annealed in O2.atmosphere increased to 78 arcsec. Compared with absorption spectra, we can conclude that the 196 nm absorption peak was caused by Li vacancies and the 73. nm peak was caused by O vacancies.

关键词： γ-LiAlO2 crystal, scanning electron micrograph (SEM), absorption spectra.

CO observations of massive star forming regions at different evolutionary phases

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2006年第5期49卷 626-640页

作者： CHEN Xi1,2. XU Ye1,3. SHEN Zhiqiang1,3.& LI Jingjing1,2.1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 2.003., china 2. Graduate School of the Chinese Academy of Sciences, beijing 10003.2. china 3. Joint institute for Galaxy and Cosmology, Shanghai Astronomical Observatory and the University of Science and Technology of china, Shanghai 2.003., china Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Graduate School of the Chinese Academy of Sciences Beijing 100034 China Joint institute for Galaxy Cosmology Shanghai Astronomical Observatory the University of Science Technology of china Shanghai 200030 China

The 12.O (J=1-0), 13.O (J=1-0) and C18O (J=1-0) emissions in 9 massive star forming regions, which are believed to be at different stages of massive star formation, were mapped with the 13.7 m millimeter wave telescope at Qinghai Station of Purple Mountain Observatory. Of the observed 9 sources, 13.O cores were detected in seven of them, and C18O cores in five of them. And only two sources associated with C18O cores and H2. masers showed the extended structures and strong outflows. This is the first detection of outflow associated with IRAS 2.566+582. in the observing field of S152.S153. The physical parameters of cores and outflows for these sources, derived from Local Thermal Equilibrium (LTE) analysis, are presented. These observing results suggest that the C18O cores will only appear when the gas density is high enough and the probability to have an outflow is very high when the clumps show the C18O and H2. maser simulta- neously.

关键词： star formation cloud core outflow H2. maser

Formation of complexes of Rubisco-Rubisco activase from La^3., Ce^3. treatment spinach

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2005年第1期48卷 67-74页

作者： HONG Fashui1, LIU Chao1, ZHENG Lei1, WANG Xuefeng1, WU Kang1, SONG Weiping1, Lü Shipeng1, TAO Ye2.& ZHAO Guiwen3.1. College of Life Sciences, Suzhou Universty, Suzhou 2.5006, china 2. Synchrotron Radiation Laboratory, {2. of High Energy physics, The Chinese Academy of Science, {3. 10003., china 3. Chemical Department, University of Science and Technology of china, Hefei 2.0}02., china 1. College of Life Sciences Suzhou Universty 215006 Suzhou China 2. Synchrotron Radiation Laboratory Institute of High Energy Physics The Chinese Academy of Science 100039 Beijing China 3. Chemical Department University of Science and Technology of China 230026 Hefei China

The complex of Rubisco and Rubisco activase from LaCl3., CeCl3. treated spinach in vivo is induced. SDS-PAGE result shows that the purified proteins from LaCl3., CeCl3. treated spinach have not only large and small subunits (55 kD, 14.4.kD) of Rubisco, but also two large subunits of 4. kD and 4. kD near the large subunits of Rubisco. Native-PAGE shows that the purified proteins from LaCl3., CeCl3. treated spinach have not only a band of Rubisco (560 kD), but also a band of about 1100 kD, about twice distant from Rubisco, which might be a complex of Rubisco and Rubisco activase. The purified enzyme activities from LaCl3., CeCl3.treated spinach are 1.8 and 2.8 times that of the control,the intensities of absorption and fluorescence are sig- nificantly higher than that of the purified Rubisco from the control, and the total sulfhydryl groups and available sulfhydryl groups are 3.—3. –SH per mol enzyme, 14.2. –SH per mol enzyme more than those of the purified Rubisco from the control, respectively. The CD spectra show that the secondary structure of the purified enzyme from LaCl3., CeCl3.-treated spinach is very dif- ferent from the control. The enzyme activities from LaCl3., CeCl3. treated spinach in vivo are 1.5 and 1.9 times those of the control.

关键词： La3., Ce3., spinach, Rubisco, complex of Rubisco and Rubisco acitivase, spectral characteristics.

Electronic structure and magnetism of Fe-doped SiC nanotubes

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 1582-1589页

作者： ZHANG WeiHu1,2.3.ZHANG FuChun3.ZHANG ZhiYong{2.LU ShuYuan5 & YANG YanNing3.1 Xi’an institute of Optics and Precision Mechanics,Chinese Academy of Sciences,Xi’an 710068,china 2.Graduate University of Chinese Academy of Sciences,{3. 1000{2.,china 3.College of {{2. and Electronic Information,Yan’an University,Yan’an 716000,china {2.Information Science and Technology Institution,Northwest University,Xi’an 71012.,china 5 Department of Telecommunications,Xi’an institute of Posts and Telecommunications,Xi’an 71012.,china 1. Xi’an institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an 710068 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. College of Physics and Electronic Information Yan’an University Yan’an 716000 China4. Information Science and Technology Institution Northwest University Xi’an 710127 China5. Department of Telecommunications Xi’an Institute of Posts and Telecommunications Xi’an 710121 China

The electronic structure and magnetic properties of Fe-doped SiC nanotubes are investigated by using the first-principles method based on density functional theory(DFT) in the local spin density approximation(LSDA).The calculation results indicate that the SiC nanotube of Fe substitution for C exhibits antiferromagnetism while ferromagnetism features prominently when Fe substitutes *** is a kind of half-metal magnetic *** formation energy calculation results show that the formation energy of ferromagnetic structure is 3.2.eV lower than that of antiferromagnetic *** atoms are more likely to replace Si ***-orbit coupling induces electron spin polarization in the ground ***,the doping Fe atoms make relaxation towards the outside of the tube to some extent and larger geometric distortion occurs when Fe substitutes C,but the whole geometric structure of SiC nanotubes is not damaged due to the *** is revealed in the calculation of energy band structure and density of states that more dispersed distribution of energy levels is produced near the Fermi *** Fe substitution for Si,obviously there are spin-split and intense p-d hybrid effects by Si 3. electron spins and Fe 3. electron spins localized at the exchanging interactions between magnetic transitional metal(TM) *** electronic density results indicate that system magnetic moments are mainly generated by the unpaired 3. electrons of Fe *** these results show that the transition metal doping SiC nanotube could be a potential route to fabricating the promising magnetic materials.

关键词： SiC nanotube the first-principles doped magnetic properties

Latest progress on interactions between VLF/ELF waves and energetic electrons in the inner magnetosphere

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2010年第3期53卷 317-326页

作者： XIAO FuLiang1,2. ZONG QiuGang3. SU ZhenPeng4. TIAN Tian3.& ZHENG HuiNan4.1 School of physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 4.0004. china 2.State Key Laboratory of Space Weather, Chinese Academy of Sciences, beijing 100190, china {4. of Space physics and Applied Technology, Peking University, beijing 100871, china 4.CAS Key Lab for Basic Plasma Science, School of Earth and Space Sciences, University of Science and Technology of china, Hefei 2.0}02., china 1. School of physics and Electronic Sciences Changsha University of Science and Technology Changsha 410004 China2. State Key Laboratory of Space Weather Chinese Academy of Sciences Beijing 100190 China3. Institute of Space Physics and Applied Technology Peking University Beijing 100871 China4. CAS Key Lab for Basic Plasma Science School of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China

Interactions between very/extremely low frequency (VLF/ELF) waves and energetic electrons play a fundamental role in dynamics occurring in the inner magnetosphere. Here, we briefly discuss global properties of VLF/ELF waves, along with the variability of the electron radiation belts associated with wave-particle interactions and radial diffusion. We provide cases of electron loss and acceleration as a result of wave-particle interactions primarily due to such waves, and particularly some preliminary results of 3. evolution of phase space density from our currently developing 3. code. We comment on the existing mechanisms responsible for acceleration and loss, and identify several critical issues that need to be addressed. We review latest progress and suggest open questions for future investigation.

关键词： wave-particle interaction VLF/ELF waves energetic electrons acceleration and loss inner magnetosphere

Current distribution and stability of LTS/HTS hybrid superconducting conductors

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第7期53卷 2000-2007页

作者： GUAN XiaoJin1,2. WANG YinShun1 & ZHOU WeiWei3.1 Key Laboratory of HV and EMC beijing, North {2. Electric Power University, beijing 102.06, {2. 2.Department of {4., Baoding University, Baoding 071000, {2. 3.institute of Electrical Engineering, Chinese Academy of Sciences, beijing 100190, {2. 1. Key Laboratory of HV and EMC beijing North China Electric Power University Beijing 102206 China2. Department of Physics Baoding University Baoding 071000 China3. Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100190 China

Current distribution and stability of a hybrid LTS/HTS superconductor, consisting of multifilamentary NbTi/Cu and Bi2.2.0}Ag tapes, were numerically analyzed according to power-law models. The results showed that most of current passed through the LTS and the current increased in the HTS with temperature rise when the transport current was below the critical current of the hybrid conductor. The quench propagation velocity of the hybrid conductor was smaller but its minimum quench energy was larger than those of LTS conductors, indicating that the stability of the hybrid superconducting conductor was effectively improved and a high engineering current density was simultaneously achieved. Finally, a hybrid sample, made by soldering Bi2.2.0}Ag tape onto NbTi/Cu conductor, was prepared and tested successfully at helium temperature. The experimental results qualitatively agreed with the simulated ones.

关键词： distribution hybrid conductor minimum quench energy quench propagation velocity n value stability

Regional soil moisture simulation for Shaanxi Province using SWAT model validation and trend analysis

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2010年第4期53卷 575-590页

作者： LI MingXing1,2.MA ZhuGuo1 & DU JiWen3.1 Key Laboratory of Regional Climate-Environment Research for Temperate East Asia,institute of {2. physics,Chinese Academy of Sciences,{3.,{4. 2.Graduate University of Chinese Academy of Sciences,beijing 10004.,{4. 3.Shaanxi Administration of Meteorology,Xi’an 710014.{4. 1. Key Laboratory of Regional Climate-Environment Research for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Shaanxi Administration of Meteorology Xi’an 710014 China

The soil moisture in Shaanxi Province,a region with complex topography,is simulated using the distributed hydrological model Soil Water Assessment Tool(SWAT).Comparison and contrast of modeled and observed soil moisture show that the SWAT model can reasonably simulate the long-term trend in soil moisture and the spatiotemporal variability of soil moisture in the *** to NCEP/NCAR and ERA4. reanalysis of soil moisture show that the trend of variability in soil moisture simulated by SWAT is more consistent with the *** model results suggested that high soil moisture in surface soil layers appears in the southern Shaanxi with high vegetation cover,and the Qinling mountainous region with frequent orographic *** deeper soil layers,high soil moisture appears in the river basins and *** regional soil moisture showed a generally decreasing trend on all soil layers from 1951 to 2.04.with a stronger and significant decreasing trend in deeper soil layers,especially in the northern parts of the province.

关键词： SWAT soil moisture content simulation validation trend analysis

Dynamics of morphological changes for mitochondrial fission and fusion

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第4期53卷 680-689页

作者： WANG ShiQi 1,2.4., FU ChangLiang 1,2., ZHANG Yan 1,2., CHEN Quan 3.& LONG Mian 1,2.1 Key Laboratory of Microgravity (National Microgravity Laboratory), {2. 100190, china 2.Center for Biomechanics and Bioengineering, {3. of Mechanics, Chinese Academy of Sciences, {2. 100190, china 3.State Key Laboratory of Biomembrane and Membrane Biotechnology, {3. of Zoology, Chinese Academy of Sciences, {2. 100101, china 4.{3. of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, {2. 10004., china 1. Key Laboratory of Microgravity (National Microgravity Laboratory) Beijing 100190 China2. Center for Biomechanics and Bioengineering Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China4. Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China3. State Key Laboratory of Biomembrane and Membrane Biotechnology Institute of Zoology Chinese Academy of Sciences Beijing 100101 China

Mitochondria experience continuous fusion and fission in a living cell, but their dynamics remains poorly quantified. Here a theoretical model was developed, upon a simplified population balance equation (PBE), to predict the morphological changes induced by mitochondrial fission and fusion. Assuming that both fission and fusion events are statistically independent, the survival probability of mitochondria staying in the fission or fusion state was formulated as an exponentially-decayed function with time, which depended on the time-dependent distribution of the mitochondrial volume and the fission and fusion rates. Parametric analysis was done for two typical volume distributions. One was Gamma distribution and the other was Gaussian distribution, derived from the measurements of volume distribution for individual mitochondria in a living cell and purified mitochondria in vitro. The predictions indicated that the survival probability strongly depended on morphological changes of individual mitochondria and was inversely correlated to the fission and fusion rates. This work provided a new insight into quantifying the mitochondrial dynamics via monitoring the evolution of the mitochondrial volume.

关键词： mitochondria morphology fission fusion dynamics modeling

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

在线全文

学校读者我要写书评

暂无评论

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 {2. of atmospheric {3., Chinese Academy of Sciences, beijing 10002., {4. 2.Chinese Academy of Meteorological Sciences, beijing 100081, {4. 3.Graduate University of Chinese Academy of Sciences, beijing 10004., {4. 4.Cold and Arid Regions Environmental and Engineering Research {2., Chinese Academy of Sciences, Lanzhou 73.000, {4. 5 The National Snow and Ice Data Center, University of Colorado, Boulder, CO 803.9-04.9, USA 1. institute of atmospheric {2. 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°2.′S, 70°2.′E), we applied the model to simulate the seasonal temperature variation within a depth of 2. 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