检索结果-南通市图书馆

Highly regio-and stereo-selective copolymerization of CO_2 with racemic propylene oxide catalyzed by unsymmetrical (S,S,S)-salenCo(Ⅲ) complexes

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2010年第8期53卷 1646-1652页

作者： REN WeiMin,ZHANG WenZhen & LU XiaoBing state key laboratory of Fine Chemicals Dalian University of Technology,Dalian 116012,China state key laboratory of Fine Chemicals Dalian University of Technology Dalian China

A novel unsymmetrical (S,S,S)-salen ligand bearing a derived chiral-BINOL was synthesized by the reaction of the condensation product of (1S,2S)-1,2-diaminocyclohexane mono(hydrogen chloride) with 3-adamanyl-5-tert-butyl-2-hydroxybenzalde-hyde and 3-formoyl-2-hydroxy-2'-alkyloxy-1,1'-binaphthyl,which originated from (S)-1,1'-bi-2-naphthol via a four-step *** cobalt complexes of this ligand,in conjunction with a nucleophilic cocatalyst,exhibited excellent activity in catalyzing asymmetric,regio-and stereo-selective copolymerization of CO2 and racemic propylene *** highest record of kinetic resolution coefficient (Krel) was obtained with the use of binary catalyst system consisting of (S,S,S)-salenCo(III) complex 1c and bulky bis(triphenylphosphine)-iminium chloride (PPNCl).The resulting poly(propylene carbonate)s have more than 99% carbonate linkages and more than 98% head-to-tail content.

关键词： carbon dioxide propylene oxide polycarbonate stereochemistry asymmetric catalysis polymerization kinetic resolution

Efficient delivery of human clotting factor IX after injection of lentiviral vectors in utero

在线全文

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2004年第6期25卷 87-91页

作者： Xiao-guang CHEN1, Huan-zhang ZHU1, Ju-li GONG, Feng LI, Jing-lun XUE2 state key laboratory of genetic Engineering, Institute of genetics, Schoolof Life Sciences, Fudan University, Shanghai 200433,China Institute of genetics School of Life Sciences Fudan University State Key Laboratory of Genetic Engineering 上海 200433

AIM: To explore gene transfer feasibility for human clotting factor IX (hFIX) mediated by recombinant lentivirus in utero. METHODS: ICR mice fetus at 17-19 d gestation were received lentiviral vectors carrying hFIX cDNA under the control of liver specific promoter by intrahepatic injection. The expression and distribution of hFIX cDNA and possible immune responses against the hFIX were assessed by ELISA, PCR, RT-PCR, and immunohistochemistry, respectively. RESULTS: The serum hFIX protein were detected at different time points in all newborn mice, the highest level of hFIX was 50 μg/L and lasted for more than 30 d. Anti-hFIX antibody was not detected. hFIX cDNA was detected in liver, spleen, and heart. The expression of hFIX cDNA was only detected in liver. Besides, no germ line transmission was found at DNA and RNA levels, and no side effect associated with gene transfer was detected. CONCLUSION: The efficient delivery of hFIX can be achieved by prenatal gene transfer. It thus shows the feasibility of gene therapy for hemophilia in utero.

关键词： lentiviral vector factor IX gene transfer techniques in utero

Zircon LA-ICPMS study and petrogenesis simulation of Dahuabei pluton in the Wulashan area,Inner Mongolia

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2009年第12期19卷 1727-1737页

作者： Dapeng Li~(a,b),Yuelong Chen~(a,*),Liemeng Chen~c,Zhong Wang~d,Jinbao Liu~d a School of Earth Sciences and resources,China University of Geosciences(Beijing),Beijing 100083,China b state key laboratory of Geological Process and Mineral resources,China University of Geosciences,Wuhan 430074,China c state key laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550002,China d Geological Survey Institute of Inner Mongolia,Hohhot 010010,China School of Earth Sciences and resources China University of Geosciences (Beijing) Beijing 100083 China state key laboratory of Geological Process and Mineral resources China University of Geosciences Wuhan 430074 China state key laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Geological Survey Institute of Inner Mongolia Hohhot 010010 China

Dahuabei pluton in the Wulashan area,Inner Mongolia,is an alkaline and peraluminous granitic ***-ICPMS U-Pb dating of zircons indicates that this pluton crystallized at 330±10 *** pluton did not experience apparent zircon *** consistent temperatures between Zr saturation(765℃) and the average zircon-rutile Ti equilibrium(780℃),together with zircon ages and their CL images,indicated that there were no inherited zircons in this *** the simulation of the dry-system crystallization process of magma cooling at 200 MPa and 1100-709℃,the phase diagram and composition evolution tendency of different phases were *** magma reached its liquidus at 1069℃.Sanidine was the first crystallized phase;at 709℃the residual magma was less than 4%,and the range of 1069-719℃should be the most suitable approach to the real *** is shown that at least some part of the pluton underwent such isobaric equilibrium crystallization processes during its crystallization.

关键词： Dahuabei pluton Petrogenesis simulation Geochemistry Zircon LA-ICPMS

Ostracod fauna across the Permian-Triassic boundary at Chongyang, Hubei Province, and its implication for the process of the mass extinction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2010年第6期53卷 810-817页

作者： LIU Hao1, WANG YongBiao1, YUAN AiHua2, YANG Hao1, SONG HaiJun1 & ZHANG SuXin21 key laboratory of Biogeology and Environmental Geology of Ministry of Education, Wuhan 430074, China 2 state key laboratory of Geological Processes and Mineral resources, Wuhan 430074, China key laboratory of Biogeology and Environmental Geology of Ministry of Education Wuhan China state key laboratory of Geological Processes and Mineral resources Wuhan China

Thirty species of 10 ostracod genera were identified from 440 fossil specimens isolated through the hot acetolysis of the rock samples collected across the Permian-Triassic boundary at Chongyang section. Twenty species of 6 genera are found to occur in the limestone of Changxing Formation, and 11 species of 7 genera above the main faunal mass extinction horizon. The os-tracod assemblages identified at the Chongyang section are obviously different from those previously reported in the contem-poraneous microbialites in Guangxi and Chongqing regions, not only in the ostracod components but also in the abundance of filter-feeding ostracods relative to the deposit-feeding ostracods, an indicator of the oxygen level of the seawater. This spatial difference in ostracod assemblages might reflect the diversity of oceanic environmental conditions after the end-Permian mass extinction. Ostracods disappear at 200 cm below and near the main mass extinction horizon, and on the top of the microbialites, respectively, showing an episodic and gradual collapse process at the Chongyang section. The carbon isotope composition is found to appear at 200 cm below the main mass extinction horizon, indicating the initial deterioration of oceanic environment. Fluctuation of the carbon isotope composition is obviously related with the episodic evolution of ostracod species, but not with the abundance of ostracods.

关键词： ostracod microbialite Permian-Triassic mass extinction Chongyang

Estimation to the turbulent kinetic energy dissipation rate and bottom shear stress in the tidal bottom boundary layer of the Yellow Sea

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第3期17卷 289-297页

作者： LIU Zhiyu and WEI Hao (key laboratory of Physical Oceanography, state Education Ministry, Ocean University of China, Qingdao 266003, China) key laboratory of Physical Oceanography Ocean University of China Qingdao 266003 China

High frequency velocity fluctuations were measured by using an acoustic Doppler velocimeter (ADV) in the tidal bottom boundary layer (BBL) of the Yellow Sea (YS) for 25 h. The turbulent kinetic energy dissipation rate and the bottom shear stress were estimated and analyzed. Results show that: (1) in the tidal BBL of the YS, the variations of the dissipation rate and the bottom shear stress during 25 hare (1.8×10-8-3.4×10 -5) W·kg-1 and (6.6×10-4-7.5×10-1) N·m - 2 respectively, indicating that there are strong dissipations in the tidal BBL of the YS; (2) in the well-mixed tidal BBL, the turbulence is mainly shear-induced locally and the production and dissipation are generally in equilibrium; (3) for the seas where the semidiurnal tidal current is dominant, both the dissipation rate and the bottom shear stress exhibit a strong quarter-diurnal variation; (4) the mean bottom drag coefficient Cd (0.45) is 0.0017 (corresponding Cd( 1.00) = 0.0015), but it has significant variations (0.0005-0.0082). The mean bottom roughness length is 2.8×10-5 m.

关键词： tidal bottom boundary layer turbulent kinetic energy dissipation rate bottom shear stress ADV the Yellow Sea.

Use of Magic Angle Spinning ~1H NMR Spectroscopy to Monitor Reactions in Solid-Phase Synthesis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1997年第12期8卷 0-0页

作者： Ai Ming YU Hua Zheng YANG(The state key laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071)Ping Chuan SUN Zhen Pu ZHANG Ming LI(The state key laboratory of Functional Polymeric Materials for Adsorption and Separation,Nankai Uni state key Lab. Elemento-Organ. Chem. Nartkai University Tianjin 300071 China state key Lab. Funct. P.M.A./S. Nankai University Tianjin 300071 China

Proton NMR-spectra of Wang resin bound compounds were obtained using the magic angle spinning 1HNMR technique with standard equipment. It was possible to analyse the spectra to evaluate their utility in solid-phase ch... 详细信息

关键词： NMR Spectroscopy to Monitor Reactions in Solid-Phase Synthesis Use of Magic Angle Spinning DCC DCM

ANALYSIS OF SOLUBLE CHEMICAL TRANSFER BY RUNOFF WATER IN FIELD

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2008年第3期20卷 382-390页

作者： TONG Ju-xiu YANG Jin-zhong state key laboratory of Water resources and Hydropower Engineering Science Wuhan University Wuhan430072 China

In order to determine the main factors influencing soluble chemical transfer and corresponding techniques for reducing fertilizer loss caused by runoff in irrigated fields, a physically based two-layer model was developed with incomplete mixing theory. Different forms of incomplete mixing parameters were introduced in the model, which was successfully verified with previous published experimental data. According to comparison, the chemicals loss of fertilizer is very sensitive to the runoff-related parameter while it is not sensitive to the infiltration-related parameter. The calculated results show that the chemicals in infiltration water play an important role in the early time of rainfall even with saturated soil, and it is mainly in the runoff flow in the late rainfall. Therefore, prevention of shallow subsurface drainage in the early rainfall is an effective way to reduce fertilizer loss, and the coverage on soil surface is another effective way.

关键词： soluble chemical transfer runoff incomplete mixing sensitive infiltration

A new method for designing a developable surface utilizing the surface pencil through a given curve

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第1期18卷 105-110页

作者： Hongyan Zhao,Guojin Wang* Department of Mathematics and state key laboratory of CAD&CG,Zhejiang University,Hangzhou 310027,China Department of Mathematics and state key laboratory of CAD&CG Zhejiang University Hangzhou 310027 China

This paper proposes a new method for designing a developable surface by constructing a surface pencil passing through a given curve, which is quite in accord with the practice in industry design and *** utilizing the Frenet trihedron frame,we derive the necessary and suffcient conditions to construct a developable surface through a given *** the requirements in shoemak- ing and garment-manufacture industries,we also study the special case of specifying the given curve as a *** given geodesic can be classified into three types corresponding to each type of developable *** also present the polynomial representation of the developable *** algorithm is convenient and effcient for applications in engineering.

关键词： CAD/CAM Developable surface Geodesic Frenet frame

Research and development on transonic compressor of high pressure ratio turbocharger for vehicle internal combustion engines

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2010年第7期53卷 1817-1823页

作者： ZHENG XinQian, ZHANG YangJun & YANG MingYang state key laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China state key laboratory of Automotive Safety and Energy Tsinghua University Beijing China

The pressure ratio required for a turbocharger centrifugal compressor increases with internal combustion engine power density. High pressure ratio causes a transonic flow field at the impeller inducer. Transonic flow narrows the stable flow range and de-teriorates stage efficiency. In this work, an advanced high pressure ratio transonic compressor was designed. The experimental results show that the maximum pressure ratio of this turbocharger is about 4.2, the maximum efficiency is above 80% and the stable flow range at the designed rotating speed is up to 34%. A turbocharger with this transonic compressor has been applied to some vehicle research actually, and improved power density by 40%.

关键词： turbocharger internal combustion (IC) engine compressor high pressure ratio transonic