检索结果-南通市图书馆

Ultrafast excitation relaxation in light-harvesting complex LH2.from *** 601

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2004年第3期47卷 192-199页

作者： GUO Lijun1,2. LIU Yuan3, LIU Weimin2. GUO Junhua1, XU Chunhe3 & QIAN Shixiong2.1. school of Physics and Information Optoelectronics, Henan University, Kaifeng 475001, china 2. Physics Department, Fudan University, {2. 2.0433, china 3. {2. Institute of Plant Physiology, Chinese Academy of Sciences, {2. 2.0032. china school of Physics and Information Optoelectronics Henan University Kaifeng 475001 China

The energy relaxation and kinetic evolution of transient spectra of bacteriochloro- phylls (BChls) in light-harvesting complex LH2.from Rb. sphaeroides 601 were investigated using femtosecond pump-probe technique. Upon 783 nm excitation, the energy at B800 BChls ex-periences an intramolecular redistribution with 0.35 ps time constant before transferring to B850 BChls. With tuning the excitation wavelength, the dynamical evolution of excited BChls was clearly observed, which indicates an obvious competition between the ground state bleaching and excited state absorption (ESA) of BChls involved and an isosbestic point near 818 nm, and also demonstrates that from the lower electronic excited state of B800 BChls to the higher exci-tonic state of B850 BChls is an efficient routine for energy transfer. The excitation energy in higher excitonic states of B850 BChls relaxes rapidly to the next lowest excitonic state by inter-conversion, delocalization to adjacent molecular, populating the lowest excitonic state and the change of molecular conformation.

关键词： photosynthesis, light-harvesting complex, energy transfer, ultrafast, dynamics, purple bacteria.

Sulfonic Acid Modified Hollow Silica Spheres and Its Application in Proton Exchange Membranes

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) 2011年第5期26卷 837-842页

作者：朱敏袁俊杰 school of Materials Science and engineering Tongji University Key Laboratory of Advanced Civil engineering Materials Minstry of EduationTongji University

In order to improve the proton conductivity of hollow silica spheres （HSS）/perfluorosulfonic acid ion-exchange （PFSA） composite membranes as proton exchange membrane,sulfonic acid groups were grafted onto the surfaces of HSS via post grafting *** images and FT-IR spectra of the obtained sulfonic acid groups modified hollow silica spheres （SAMHSS） illustrated that the sulfonic acid groups were successfully grafted onto the surfaces of *** uptake and swelling degree of SAMHSS/PFSA composite membranes were found much higher than those of HSS/PFSA membranes due to the introduction of hydrophilic sulfonic acid *** a range from 50 ℃ to 130 ℃,the highest conductivity of composite membranes was obtained when 5 wt% SAMHSS was *** maximum conductivity reached 7.5×10-2.S·cm-1 at 100 ℃ and 100% relative humidity,even the temperature increased to 130 ℃,the conductivity of composite membranes with 5 wt% SAMHSS could reach 3.7×10-2.S·cm-1 at 100 % relative humidity,while the conductivity of the recast PFSA was only 2.2.10-3 S·cm-1.

关键词： composite hollow silica spheres proton exchange membrane sulfonation conductivity

New Mg_2.i based Alloy for Automobile Engine Cylinder Liner

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) 2011年第4期26卷 797-800页

作者：张道文 school of transportation and Automotive {2. Xihua University

New Mg2.i based alloy were prepared by mechanical alloying. Sintering temperature was from 82. to 865K, which indicated that few Mg2.i were produced at lower temperature while MgO were produced at higher temperature. Microstructure image showed that at sintering temperature of 855K, Mg2.i were mostly synthesized with the reaction of purity magnesia powder and silicon powder. Hardness and wear tests proved that the new synthetic silicon magnesium alloy had higher hardness and good wear resistance. Under the same testing conditions, it is found that the hardness of the new material is 42..50, and pure magnesium is only *** the same experiments it is also found that under the same pressure, pure magnesium alloys than silicon wearing capacity of pure magnesium is 2.times as high that of Mg2.i based alloy. It shows that Mg2.i based alloy is the ideal material for the wear parts of car engine cylinder liner because of its small density, stable dimension, high hardness and wear-resisting.

关键词： cylinder liner Mg2.i based alloy hardness wear-resisting

NUMERICAL ANALYSIS OF THE 3-D FLOW FIELD OF PRESSURE ATOMIZERS WITH V-SHAPED CUT AT ORIFICE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第2期23卷 187-192页

作者： ZHOU Hua school of Aerospace engineering and Applied Mechanics Tongji University Shanghai 200092 China

Axisymmetric liquid jets have been studied extensively for more than one century, while non-axisymmetric jets are also very common in engineering applications but attract less concern. Based on Eulerian fluid-fluid model in Fluent software, this article analysizes the 3-D flow fields of pressure atomizers with V-shaped cut at orifice, which will result in a non-axisymmetric liquid jet. Flow rate analysis and jet structure analysis are carried out, the results show that the flow rate can be formulated by adding a correction coefficient to the formula of inviscid axisymmetric jets in atomization regime, when the Weber number is low enough to make the flow fall out of atomization regime, and the jet structure together with the flow rate formula will change. Analysis shows that the evolution of the spray and therefore the structure of the liquid jet are affected much by relative velocity and the local volume fraction of liquid phase.

关键词： flow rate fraction distribution gas-liquid interference non-axisymmetric liquid jet pressure atomizer

New Receiving Mode of Extinction for Determining Particle Size and Density without Convex Lens

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Lasers 2002年第1期11卷 46-51页

作者： WU Weiliang CHEN Hanping (school of Power and Energy engineering, {2. Jiao Tong University, {2. 2.0030, china) CAI Xiaoshu WANG Naining (school of Power and Energy engineering, University of {2. for Science and Technology, {2. 2 school of Power and Energy engineering Shanghai Jiao Tong University 上海 200030 school of Power and Energy engineering University of Shanghai for Science and Technology 上海 200093

In this article a new receiving mode for scattering light by particle is theoretically discussed. Using this receiving mode the convex lens can be omitted during determining the extinction of particle. Therefore the extinction coefficient of sphere particles is redefined by extrapolating the conventional one. In terms of the calculation results of light scattering the definition of near-field extinction coefficient of a swarm particle is depicted. Through the error analysis it is proved that the error coming from the new definition of extinction coefficient is acceptable for engineering application. In addition, a technique for determining the particle size and density is presented in this article and the advantage using this receiving mode is described.

关键词： extinction of particle light scattering fluctuation method particle size particle density

Anticoagulation property and security of artificial heart valve material

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) 2005年第2期48卷 145-162页

作者： WANG Xianghui1, , LIU Xianghuai1,2., 3, ZHANG Feng2. LI Changrong2. YU Liujiang2. ZHENG Zhihong2. WANG Xi2. JIANG Zhenbin4, CHEN Anqing4 & XU Jingfang3 1. Department of Physics, East china Normal University, shanghai 2.0062. china 2. Ion Beam Lab, shanghai Institute of Mini-system and information, Chinese Academy of Sciences,shanghai 2.0050, china 3. Department of Electronics, school of Information Science and Technology, East china Normal Univer- sity, shanghai 2.0062. china 4. shanghai Cardiovascular Institute, Zhongshan Hospital, shanghai 2.0032. china Arctic & Antarctic Res Inst Dept Geophys St Petersburg 199226 Russia Department of Physics East China Normal University Shanghai 200062 China

Heart valve diseases threaten human health. One reliable way to save lives of such patients is to replace the pathologically changed heart valves by artificial ones. Over 2.million patients have received LTI-carbon heart valve’s implantation. However, the thrombosis after the implantation is one of the difficulties that need to be solved. In order to improve the blood compatibility and security of mechanical heart valves, ion beam technology was used to modify the surface properties of the materials. The investigation results have been summarized in this paper.

关键词： artificial heart valve, ion implantation, plasma immersed ion implantation, ion beam enhanced deposition.

Elastic Modulus of 304 Stainless Steel Coating by Cold Gas Dynamic Spraying

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第3期19卷 73-78页

作者： HAN Wei1, MENG Xian-ming1, ZHANG Jun-bao2. ZHAO Jie1 (1. school of Material Science and engineering, Dalian University of Technology, Dalian 116085, Liaoning, {2. 2. Baoshan Iron and Steel Company Limited, Baosteel Research Institute, shanghai 2.1900, {2.) school of Material Science and engineering Dalian University of Technology Dalian Liaoning China Baoshan Iron and Steel Company Limited Baosteel Research Institute Shanghai China

304 stainless steel coating was deposited on the IF steel substrate by cold gas dynamic spraying （CGDS）, and the elastic modulus of the 304 stainless steel coating was studied. The elastic modulus of cold sprayed 304 stain- less steel coating was measured using the three-point bend testing and the compound beam theory, and the other me- chanic parameters （such as the equivalent flexural rigidity and the moment of inertia of area） of the coatings were also calculated using this compound beam theory. It is found that the calculated results using the above methods are accu- rate and reliable. The elastic modulus value of the cold sprayed 304 stainless steel coating is 1. 179 X 105 MPa, and it is slightly lower than the 304 stainless steel plate （about 2.X 105 MPa）. It indicates that the elastic modulus of the cold sprayed coatings was quite different from the comparable bulk materials. The main reason is that the pores and other defects are existed in the coatings, and the elastic modulus of the coatings also depends on varies parameters such as the feed stock particle size, porosity, and processing parameters.

关键词： cold gas dynamic spraying 304 stainless steel coating three-point bend testing compound beam theory elastic modulus

Diatomaceous silica filter aid filtration for the effective separation of colloidal Cr（OH）＿3 precipitate from tanning wastewater

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 1995年第2期7卷 151-156页

作者： Zhao Youcai Xi Diming Chen Shaowei(school of Environrnental engineering , {2. University, shanghai 2.0092 , china)

ＤｉａｔｏｍａｃｅｏｕｓｓｉｌｉｃａｆｉｌｔｅｒａｉｄｆｉｌｔｒａｔｉｏｎｆｏｒｔｈｅｅｆｆｅｃｔｉｖｅｓｅｐａｒａｔｉｏｎｏｆｃｏｌｌｏｉｄａｌＣｒ（ＯＨ）＿３ｐｒｅｃｉｐｉｔａｔｅｆｒｏｍｔａｎｎｉｎｇｗａｓｔｅ... 详细信息

ＤｉａｔｏｍａｃｅｏｕｓｓｉｌｉｃａｆｉｌｔｅｒａｉｄｆｉｌｔｒａｔｉｏｎｆｏｒｔｈｅｅｆｆｅｃｔｉｖｅｓｅｐａｒａｔｉｏｎｏｆｃｏｌｌｏｉｄａｌＣｒ（ＯＨ）＿３ｐｒｅｃｉｐｉｔａｔｅｆｒｏｍｔａｎｎｉｎｇｗａｓｔｅｗａｔｅｒＺｈａｏＹｏｕｃａｉ；Ｘ...

关键词： diatornaceous silica filter acid filtration tanning wastewater colloidal Cr(OH)_3 precipitate.

Preparation and Magnetic Properties of Mn-Zn Ferrites by the Co-precipitation Method

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) 2009年第6期24卷 875-878页

作者：李雪张俊喜 school of Environmental and Chemical engineering Shanghai University Electrochemical Research Group Shanghai University of Electric PowerKey Laboratory of State Power Corporation of China

Mn-Zn ferrites （Mn1-xZnxFe2.4） with different compositions were prepared by the coprecipitation method, and the influences of such synthesis conditions as pH value, composition and volume ratio （R） of the mixed solution and NH4HCO3 solution on their microstructures and magnetic properties were discussed. The samples were characterized by X-ray diffraction （XRD） and magnetization measurement instrument. Lattice parameters and average crystalline size of the synthesized materials were calculated from the corresponding XRD patterns with the related software Jade.5. For samples of different pH values, only one phase was found when pH values were 7.0, 8.0 and 9.0. The sample with pH value of 7.0 exhibited the highest saturation magnetic induction, the lowest coercive force, and crystallized best. For samples of different R values with pH value of 7.0, only one phase was observed in all samples, and the sample with R value of 2.3 exhibited the highest saturation magnetic induction and the lowest coercive force. The composition has mainly afected the magnetic properties, and the saturation magnetic induction increases with the increase of the content of Zn （x）, but decreases when x is beyond 0.6. The trend of coercive force is on the contrary. However, no magnetism is exhibited when the x value is up to 0.8.

关键词： co-precipitation method microstructure magnetic property Mn-Zn ferrite