检索结果-南通市图书馆

Science China Chemistry 2006年第2期49卷 162-168页

作者： CUI Wenquan1,3. LIU Li2. FENG Liangrong1, XU Chenghua1, LI Zijian1, Lü Shaojie1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China 2. Chemistry Department, Sichuan university of Science & Engineering, Zigong 643.3., China 3. Graduate school of the Chinese Academy of Sciences, Beijing 10003., China Correspondence should be addressed to Qiu Fali 1. Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 China 3. Graduate school of the Chinese Academy of Sciences Beijing 100039 China 2. Chemistry Department Sichuan University of Science & Engineering Zigong 643033 China

A layered perovskite-type oxide K2.a2.i3.10 was prepared with high-temperature solid-state reaction, and characterized with X-ray diffraction (XRD) and ultraviolet-visible diffuse re-flectance spectroscopy (UV-Vis DRS). Platinum was loaded onto K2.a2.i3.10 as a co-catalyst with different methods. The dispersion of platinum on K2.a2.i3.10 was determined with HOT method. The photocatalytic activity of Pt/K2.a2.i3.10 was studied. This catalyst showed much higher activity in hydrogen evolution reaction than Ni/K2.a2.i3.10. The effects of different amounts of loaded platinum and several preparation methods were evaluated. The best achieved hydrogen evolution rate was 2.0}.88 μmol·h?1 by Pt(2.)/K2.a2.i3.10. A possible band structure and mechanism were discussed based on the results.

关键词： photocatalysis hydrogen platinum K_2.a_2.i_3._(10) support

Determination of the Thermal Expansion Coefficient of Concrete at Early Ages by Using Temperature-stress Testing Machine

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials Science) 2006年第4期21卷 146-149页

作者：霍凯成 Hubei Key Laboratory of Roadway Bridge & Structure Engineering Wuhan University of TechnologyWuhan 430070China

By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved ： temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice.

关键词： concrete coefficient of thermal expansion temperature-stress test

Debating about the climate warming

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第1期16卷 1-6页

作者： WANG Shaowu1, LUO Yong2. ZHAO Zongci2. DONG Wenje2.and YANG Bao3.(1.Department of Atmospheric Sciences, school of Physics, Peking {2., Beijing 100871, China 2. Laboratory for Climate Studies, China Meteorological Administration, Beijing 100081, China 3. Institute of Cold and Arid Regions Environmental and Engineering, Chinese Academy of Sciences, Lanzhou 73.000, China) [a] Department of Atmospheric Sciences School of Physics Peking University Beijing China [b] Laboratory for Climate Studies China Meterological Administration Beijing China [c] Institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou China

Debating about the climate warming is reviewed. Discussions have focused on the validity of the temperature reconstruction for the last millennium made by Mann et al. Arguments against and for the reconstruction are introduced. Temperature reconstructions by other authors are examined, including the one carried out by Wang et al. in 1996. It is concluded that: (1) Ability of reproducing temperature variability of time scale less than 10 a is limited, so no sufficient evidence proves that the 1990s was the warmest decade, and 1998 was the warmest year over the last millennium. (2. All of the temperature reconstructions by different authors demonstrate the occurrence of the MWP (Medieval Warm Period) and LIA (Little Ice Age) in low frequency band of temperature variations, though the peak in the MWP and trough in LIA varies from one reconstruction to the others. Therefore, terms of MWP and LIA can be used in studies of climate change. (3. The warming from 1975 to 2.00 was significant, but we do not know if it was the strongest for the last millennium, which needs to be proved by more evidence.

关键词： climate warming MWP LIA the 2.th century.

Fractal Analysis of Gas Diffusion Layer in PEM Fuel Cells

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials Science) 2006年第1期21卷 22-25页

作者：石英肖金生 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070ChinaSchool of Automation Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070ChinaSchool of Automotive EngineeringWuhan University of Technology Wuhan 430070China

The aim of this study is to show how fractal analysis can be effectively used to characterize the texture of porous solids. The materials under study were carbon papers, the backing material of the gas diffusion layer （GDL） in Proton Exchange Membrane Fuel Cell （PEMFC）. The fractal dimensions were calculated by analyzing data from mercury porosimetry. The polytotrafluoroethylene （PTFE） treated carbon paper shows a significantly high fractal dimension value than pare sample, and the high fractal dimension signifies that the physical complexity of the pore surface is enhanced. The fractal dimension can be used as a valid parameter to monitor the textural evolution of the samples as the treatment progresses, as this behaves in a similar way to other textural parameters. The use of fractal analysis in conjunction with the results of classical characterization methods leads to a better understanding of textural modificatious in the processing of materials.

关键词： PEMFC gas diffusion layer fractal dimension mewury porosimetry

Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

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10期17卷 1147-1151页

作者： Liu Dan1,2., Zhang Yong3.and Long Guilu1,2.1. Key Laboratory for Atomic and Molecular NanoSciences, and Department of Physics, Tsinghua university, Beijing 100084, China 2. Center of Quantum Information Science and Technology, Tsinghua National Laboratory for information Science and Technology, Beijing 100084, China 3. Institute of Physics, school of Sciences, Beijing university of Posts and Telecommunications, Beijing 100876, China) Key Laboratory for Atomic and Molecular NanoSciences and Department of Physics Tsinghua University Beijing 100084 China Center of Quantum Information Science and Technology Tsinghua National Laboratory for information Science and Technology Beijing 100084 China Institute of Physics School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ>3. namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.

关键词： Heisenberg-XY chain magnetic-current phase transition.

Orientation-Singularity Representation and Orientation-Capability Computation of a Special Class of the Gough-Stewart Parallel Mechanisms Using Unit Quaternion

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 Journal of Mechanical Engineering 2012年第6期25卷 1096-1104页

作者： LI Baokun1, 2. CAO Yi1, 3. *, ZHANG Qiuju1, and HUANG Zhen4 1 school of Mechanical Engineering, Jiangnan {2., wuxi 2.412., China 2.school of Mechanical Engineering, Anhui {2. of Science and Technology, Huainan 2.0}001, China 3.State Key Laboratory of Fluid Power Transmission and Control, Hangzhou 3.002., China 4 Robotics Research Center, Yanshan {2., Qinhuangdao 066004, China 1. school of Mechanical Engineering Jiangnan University Wuxi 214122 China 2. school of Mechanical Engineering Anhui University of Science and Technology Huainan 232001 China 3. State Key Laboratory of Fluid Power Transmission and Control Hangzhou 310027 China 4. Robotics Research Center Yanshan University Qinhuangdao 066004 China

Singular configuration seriously affects the performance of the Gough-Stewart parallel mechanism and has attracted many researchers’ attentions. However, most of existing topics often focus on the position-singularity of the mechanism for a constant-orientation, but few reports research the orientation-singularity for a given position. In order to investigate the orientation-singularity of the Gough-Stewart parallel mechanisms with two dissimilar semi-regular hexagonal platforms for a given position, after constructing the discrimination matrix of the singular configuration of the mechanism and computing the determinant of this matrix by using unit quaternion as the orientation parameters which can avoid the singularities in parameterization, a general symbolic expression representing the three-dimensional orientation-singularity locus for a given position is obtained and the three-dimensional view of the orientation-singularity locus is further described. The orientation-singularity-free void exists inside the orientation-singularity locus, but the shape of the orientation-singularity-free void is irregular and inconvenient for the design of the mechanism. The minimal inscribed sphere of the three-dimensional orientation-singularity locus namely the orientation-singularity-free ball is described. The radius of the ball orientation-capability is used as the measurement for the orientation-singularity-free void size. A new efficient algorithm is proposed for the computation of the orientation-capability. Finally, the influences of the geometry parameters and the different positions of the mechanism on the orientation-capability are discussed. A new method of the singularity analysis of the Gough-Stewart parallel mechanism is advanced based on the unit quaternion, and the research finds have important referential value for the configuration parameters optimization of this class of the parallel mechanisms with the goal of having the maximal singularity-free zone.

关键词： parallel mechanism unit quaternion orientation-singularity orientation-singularity-free void orientation-capability

Analysis of the Resveratrol-binding Protein using Phage-displayed Random Peptide Library

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2006年第5期38卷 342-348页

作者： Lei FENG Jian JIN Lian-Feng ZHANG Ting YAN Wen-Yi TAO The Key Laboratory of Industrial biotechnology,Ministry of Education,southern{2. {3.,wuxi 2.403.,China TheKeyLaboratoryofIndustrialbiotechnology MinistryofEducationSouthernYangtzeUniversityWuxi214036China

Resveratrol,a plant polyphenol,is found in significant amounts in the skin of grapes and insome traditional *** is reported to exert different biological activities,such as inhibiting lipid peroxidation,scavenging free radicals,inhibiting platelet aggregation,and anticancer *** order to screen theresveratrol-binding proteins,we synthesized biotinylated resveratrol,purified by liquid chromatography andimmobilized it into streptavidin-coated microplate wells.3.(4,5-Demethylthiazol-)-2.5-diphenyl tetrazoliumbromide assay showed little change in the anticancer activity of biotinylated resveratrol in vitro.A randomlibrary of phage-displayed peptides was screened for binding to immobilized resveratrol to isolate resveratrol-binding *** peptides were found to bind to resveratrol specifically,which was proven byenzyme-linked immunosorbent *** amino acid sequence analysis of the selected peptides andhuman proteins using the BLAST program,the results showed that resveratrol has an affinity for variousproteins such as breast cancer-associated antigen,breast cancer resistance protein,death-associatedtranscription factor,and human cyclin-dependent *** results demonstrate that our study providesa feasible method for the study of binding proteins of natural compounds using a phage-displayed randompeptide library.

关键词： resveratrol binding protein phage display anticancer activity

The steady-state solution of dendritic growth from the undercooled binary alloy melt with the far field flow

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) 2009年第8期52卷 2280-2287页

作者： CHEN MingWen1,2. WANG ZiDong2.& XU JianJun2.3.4 1 school of Applied Sciences, {2. of Science and Technology Beijing, Beijing 100083. China 2.school of Materials Science and Engineering, {2. of Science and Technology Beijing, Beijing 100083. China 3.school of Mathematical Sciences, Nankai {2., Tianjin 3.0071, China 4 Department of Mathematics and Statistics, McGill {2., Montreal H3. 2.6, Canada school of Applied Sciences University of Science and Technology Beijing Beijing 100083 China school of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China school of Mathematical Sciences Nankai University Tianjin 300071 China Department of Mathematics and Statistics McGill University Montreal H3A 2K6 Canada

The steady-state dendritic growth from the undercooled binary alloy melt with the far field flow is considered. By neglecting the interface energy, interface kinetics and buoyancy effects in the system, we obtaine the steady-state solution for the case of the large Schmidt number, in terms of the multiple variable expansion method. The changes of the temperature and concentration fields, the morphology of the interface, the normalization parameter and the Peclet number of the system induced by uniform external flow are derived. The results show that, compared with the system of dendritic growth from undercooled pure melt, the convective flow in the system of growth from undercooled binary alloy has stronger effects on the morphology of the interface. Nevertheless, the shape of the interface still remains nearly a paraboloid.

关键词： binary alloy melt convection dendritic growth interfaces steady-state solution multiple variable expansion method

Sm-Nd and zircon SHRIMP U-Pb dating of Huilanshan mafic granulite in the Dabie Mountains and its zircon trace element geochemistry

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2005年第12期48卷 2081-2091页

作者： HOU Zhenhui1, LI Shuguang1, CHEN Nengsong2. LI Qiuli1 & LIU Xiaoming3.1. school of Earth and Space Sciences, {2. of Science and Technology of China, Hefei 2.0}02., China 2. The Key Laboratory of Continental Dynamics of the Ministry of Education, Northwest {2., Xi’an 710069, China 3. Faculty of Earth Sciences, China {2. of Geosciences, Wuhan 43.074, China 1. school of Earth and Space Sciences University of Science and Technology of China 230026 Hefei China 2. The Key Laboratory of Continental Dynamics of the Ministry of Education Northwest University 710069 Xi’an China 3. Faculty of Earth Sciences China University of Geosciences 430074 Wuhan China

The mafic granulites from Huilanshan are outcropped on the center of the Luotian dome in the northern Dabie Mountains. The Sm-Nd isochron defined by granulite-facies meta-morphic minerals (garnet + clinopyroxene + hypersthene) yields an age of 13. ± 18 Ma indicating the early Cretaceous granulite-facies metamorphism. The cathodoluminescence (CL) images of zircons from the granulite show clearly core-mantle-rim structures. The zircon cores are charac-terized by typical oscillatory zoning and highly HREE enriched patterns, which suggests their magma origin. Some zircon cores among them with little Pb loss give SHRIMP U-Pb ages rang-ing from 753.to 780 Ma, which suggests that the protolith of Huilanshan granulite is Neopro-terozoic mafic rocks. The zircon mantles usually cut across the oscillatory zone of the zircon cores have 3.10 times lower REE, Th, U, Y, Nb and Ta contents than the igneous zircon cores but have high common Pb contents. These characteristics suggest that they were formed by hydrothermal alteration of the igneous zircons. The part of zircon mantles with little Pb loss give a similar SHRIMP U-Pb age (716―780 Ma) to the igneous zircon cores, which implies that the hydrothermal events occurred closely to the magmatic emplacement. In view of the strong early Cretaceous magmatism in the Luotian dome, consequently, the Huilanshan mafic granulite was formed by heating of the Neoproterozoic mafic rocks in mid-low crust, which caused the granu-lite-facies metamorphism underneath the Dabie Mountains. The similarity between the granulite metamorphic age (13. ± 18 Ma) defined by Sm-Nd isochron and K-Ar age of 12.0}12. Ma given by amphible from the gneiss in Luotian dome suggests a rapid uplifting of the Luotian dome, which may result in further exhumation of the ultrahigh pressure metamorphic rocks in the Dabie Mountains.

关键词： Dabie orogen, granulite, zircon U-Pb ages, Sm-Nd age.

Mechanisms of antiprostate cancer by gum mastic:NF-κB signal as target

在线全文

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2007年第3期28卷 446-452页

作者： Mei-lan HE~(2.4) Ang LI~2.Chun-su XU~2.Shun-li WANG~3.Meng-jie ZHANG~2.Hua GU~2.Yao-qin YANG~3.Hui-hong TAO~3.~2.nstitute of Cancer Research,Life Science and Technology school,Tongji university,Shanghai 2.0092.China ~3.ellular Morphology Center,Medical school,Tongji university,Shanghai 2.0092.China Institute of Cancer Research Life Science and Technology School Tongji University Shanghai 200092 China Cellular Morphology Center Medical School Tongji University Shanghai 200092 China

Aim:To study the effect of gum mastic,a natural resin,on the proliferation ofandrogen-independent prostate cancer PC-3.cells,and further investigate themechanisms involved in this regulatory system,taking nuclear factor κB(NF-κB)signal as the ***:3.(4,5-dimethylthiazol-2.yl)-2.5-diphenyltetrazoliumbromide(MTT)assay and a flow cytometer were used to detect the effect of gummastic on the proliferation of PC-3.***,reporter gene assay,RT-PCR,andWestern blotting were carried out to study the effects of gum mastic on the NF-κBprotein level and the NF-κB signal *** expression of genes involved inthe NF-κB signal pathway,including cyclin D1,inhibitors of κBs(IκBα),andphosphorylated Akt(p-AKT),were *** addition,transient transfectionassays with the 5×NF-κB consensus sequence promoter was also used to test theeffects of gum ***:Gum mastic inhibited PC-3.cell growth and blockedthe PC-3.cell cycle in the G1 *** mastic also suppressed NF-κB activity inthe PC-3.*** expression of cyclin D1,a crucial cell cycle regulator and anNF-κB downstream target gene,was reduced as ***,gum masticdecreased the p-AKT protein level and increased the IκBα protein ***:Gum mastic inhibited the proliferation and blocked the cell cycleprogression in PC-3.cells by suppressing NF-κB activity and the NF-κB signalpathway.

关键词： gum mastic prostate cancer NF-κB signal