检索结果-南通市图书馆

Analytical method of radiation by a wave energy device with dual rectangular floating bodies

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2010年第3期29卷 106-115页

作者： WANG Wensheng YOU Yage ZHANG Yunqiu WU Bijun YE Yin Guangzhou institute of energy Conversion Chinese Academy of Sciences Guangzhou 510640 China key laboratory of Renewable energy and Gas Hydrate Chinese Academy Sciences Guangzhou 510640 China Graduate University Chinese Academy of Sciences Beijing 100049 China

The system with one floating rectangular body on the free surface and one submerged rectangular body has been applied to a wave energy conversion device in water of finite depth. The radiation problem by this device on a plane incident wave is solved by the use of an eigenfunction expansion method, and a new analytical expression for the radiation velocity potential is obtained. The wave excitation force is calculated via the known incident wave potential and the radiation potential with a theorem of Haskind employed. To verify the correctness of this method, an example is computed respectively through the bound element method and analytical method. Results show that two numerical methods. are in good agreement, which shows that the present method is applicable. In addition, the trends of hydrodynamic coefficients and wave force are analyzed under different conditions by use of the present analytical method.

关键词： wave energy device hydrodynamic coefficients wave force analytical method

low-temperature magnetic properties of horse spleen ferritin

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2010年第27期55卷 3174-3180页

作者： TIAN lanXiang 1,2,CAO ChangQian 1,2,lIU QingSong 1,2 &PAN YongXin 1,2 1key laboratory of the Earth’s Deep Interior,institute of Geology and Geophysics,chinese academy of sciences,beijing 100029,China 2Franco-chinese Biomineralization and Nano-structures laboratory,beijing 100029,China key laboratory of the Earth’s Deep Interior Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Franco-chinese Biomineralization and Nano-structures laboratory Beijing China

The magnetic properties of the antiferromagnetic cores in ferritin are of importance in the construction and improvement of ferritin-based magnetic resonance imaging systems and their application to environmental *** this study,we carry out integrated magnetic and transmission electron microscopy analyses of horse spleen ferritin(HoSF)to understand the relationships between the magnetic behavior of HoSF and temperature,applied field and grain-size *** R-value from the Wohlfarth-Cisowski test for the investigated sample at 5 K was 0.46,indicating very weak magnetostatic interactions among the nanoparticles of *** nanoparticles of HoSF show superparamagnetic properties at room temperature,while below the blocking temperature of Tb≈12 K it has a net magnetic moment that comes from the uncompensated spins of the nanoparticle surface or *** thermal relaxation process of HoSF follows the Néel-Arrhenius *** low-temperature AC susceptibility data,we calculated the effective magnetic anisotropy energy Ea=(5.52±0.16)×10-21 J;the effective magnetic anisotropy energy constant Keff=(4.65±0.14)×10 4 J/m3 and the pre-exponential frequency factor f0 =(4.52±2.93)×1011 *** values are useful in understanding the magnetic behavior of the antiferromagnetic nanoparticles and their potential application in biomedical technology.

关键词：马脾铁蛋白低温度磁性质透射电子显微镜磁各向异性常数纳米粒子生物医学技术交流磁化率

Design of a new dynamical core for global atmospheric models based on some efficient numerical methods

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2004年第Z1期47卷 4-21页

作者： WANG Bin, WAN Hui, Jl Zhongzhen, ZHANG Xin, YU Rucong, YU Yongqiang & lIU HongtaoState key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, China Department of Computational Mathematics, academy of Mathematics and System sciences, Peking University, beijing 100871, China State key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Department of Computational Mathematics Academy of Mathematics and System Sciences Peking University Beijing China

A careful study on the integral properties of the primitive hydrostatic balance equations for baroclinic atmosphere is carried out, and a new scheme todesign the global adiabatic model of atmospheric dynamics ispresented. This scheme includes a method of weighted equal-areamesh and a fully discrete finite difference method with quadraticand linear conservations for solving the primitive equationsystem. Using this scheme, we established a new dynamical corewith adjustable high resolution acceptable to the availablecomputer capability, which can be very stable without anyfiltering and smoothing. Especially, some important integralproperties are kept unchanged, such as the anti-symmetries of thehorizontal advection operators and the vertical convectionoperator, the mass conservation, the effective energy conservationunder the standard stratification approximation, and so on. Somenumerical tests on the new dynamical core, respectively regardingits global conservations and its integrated performances inclimatic modeling, incorporated with the physical packagesfrom the Community Atmospheric Model Version 2 (CAM2) of NationalCenter for Atmospheric Research (NCAR), are included.

关键词： dynamical core, equal-area mesh, anti-symmetry, effective energy conservation.

Refraction of light in media

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2007年第5期50卷 591-600页

作者： ZHANG Tao key laboratory of Beam Technology and Material Modification of Ministry of Education, institute of low energy Nuclear physics, beijing Normal University, beijing 100875, China beijing Radiation Center, beijing 100875, China key laboratory of Beam Technology and Material Modification of Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing China beijing Radiation Center Beijing China

The roles of the magnetic field and electric field of the light are investigated when the light is refracted in the medium. The model of the electron cloud conductor is presented. Electron cloud in a molecule is treated as a conductor and the Faraday’s law is applied to this conductor that is in the alternating magnetic field of the light. dBM/dt of the light gives rise to an alternating induced current on the electron cloud conductor, and the light exchanges energy, i.e. the refractive energy, with the elec- tron cloud conductor. Formulas of refractive index, which is the ratio of light speed in vacuum to that in the medium, are derived with this model. These formulas are tested with several mediums and langevin’s diamagnetic susceptibility of helium gas, and the results are in good agreement with the measured data. The anisotropy and the nonlinearity of the refractive index are explained with the theory described in this work.

关键词： refractive index, light, speed, medium, propagation

BOUNDARY FEEDBACK STABIlIZATION OF NONUNIFORM TIMOSHENKO BEAM WITH A TIPlOAD

在线全文

学校读者我要写书评

暂无评论

chinese Annals of Mathematics,Series B 2001年第4期22卷 485-494页

作者： YAN QINGXU, FENG DEXING institute of Systems Science, academy of Mathematics and Systems Science, chinese academy of sciences, beijing 100080, China. institute of Systems Science, academy of Mathematics and Systems Science, chinese academy of sciences, Be institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

The boundary stabilization problem of a Timoshenko beam attached with a mass at one end is studied. First, with linear boundary force feedback and moment control simultaneously at the end attached with the load, the energy corresponding to the closed loop system is proven to be exponentially convergent to zero as time t →∞. Then, some counterexamples are given to show that, in other casest the corresponding closed loop system is, in general, not stable asymtotically, let alone exponentially.

关键词： Timoshenko beam Boundary feedback control C0 semigroups Exponential stability Multiplier method

Impact of volcanism on the formation and hydrocarbon generation of organic-rich shale in the Jiyang Depression, Bohai Bay Basin, China

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 1539-1551页

作者： Jia-Hong Gao Xin-Ping liang Zhi-Jun Jin Quan-You liu Chang-rong li xiao-Wei Huang Ju-Ye Shi Peng li State key laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development Institute of EnergyPeking University Petroleum Exploration and Production Research institute SINOPECBeijing100871 China School of energy Resources China University of Geosciences Beijing100083 China

Globally,most organic-rich shales are deposited with volcanic ash *** ash,a source for many sedimentary basins,can affect the sedimentary water environment,alter the primary productivity,and preserve the organic matter(OM)through physical,chemical,and biological *** an increasing number of breakthroughs in shale oil exploration in the Bohai Bay Basin in recent years,less attention has been paid to the crucial role of volcanic impact especially its influence on the OM enrichment and hydrocarbon ***,we studied the petrology,mineralogy,and geochemical characteristics of the organic-rich shale in the upper submember of the fourth member(Es_(4)^(1))and the lower submember of the third member(Es_(3)^(3))of the Shahejie Formation,aiming to better understand the volcanic impact on organic-rich shale *** results show that total organic carbon is higher in the upper shale intervals rich in volcanic ash with enriched light rare earth elements and moderate Eu *** indicates that volcanism promoted OM formation before or after the *** positive correlation between Eu/Eu*and Post-Archean Australian Shale indicates hydrothermal activity before the volcanic *** plane graph of the hydrocarbon-generating intensity(S1+S2)suggests that the heat released by volcanism promoted hydrocarbon ***,the nutrients carried by volcanic ash promoted biological blooms during Es_(4)^(1 )and Es_(3)^(3) deposition,yielding a high primary *** blooms consume large amounts of oxygen and form anoxic environments conducive to the burial and preservation of ***,this study helps to further understand the organic-inorganic interactions caused by typical geological events and provides a guide for the next step of shale oil exploration and development in other lacustrine basins in China.

关键词： Volcanic ash Hydrocarbon generation Organic-rich shale Shahejie Formation Jiyang Depression

Stochastic particle Acceleration in Blazar Jets

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Astronomy and astrophysics 2002年第1期2卷 1-7页

作者： Jian-Cheng Wang Yunnan Observatory Chinse academy of sciences, Kunming 650011 National Astronomical Observatories, chinese academy of sciences, beijing 100012 United laboratory of Optical Astronomy chinese academy of sciences Extragalactic astronomy Recei Yunnan Observatory Chinese Academy of Sciences Kunming 650011 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 United laboratory of Optical Astronomy Chinese Academy of Sciences

The bulk kinetic energy of jets can be dissipated via generating tur- bulen plasma waves. We examine stochastic particle acceleration in blazar jets to explain the emissions of all blazars. We show that acceleration of electrons by plasma turbulence wavs with a spectrum W(k) ~ k^(-4/3) produces a nonthermal population of relativistic electrons whose peak frequency of synchrotron emission can fit the observational trends in the spectral energy distribution of all blazars. The plasma nonlinear processes responsible for the formation of turbulent spectrum are investigated. Increases in the ioteraction time of turbulent waves can produce a fiatter spectrum leading to efficient particle acceleration.

关键词： acceleration of paxticles - blazars: theory - plasma: turbulence - radiation mechanism: nonthermal

A preliminary study on fingerprinting approach in marine sediment dynamics with the rare earth elements

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2010年第4期29卷 62-77页

作者： ZHOU xiaojing lI Anchun JIANG Fuqing MENG Qingyong key laboratory of Marine Geology ＆ Environment Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China Graduate School of the chinese academy of sciences Beijing 100039 China

locating the quantitized natural sediment fingerprints is an important work for marine sediment dynamics *** total of 146 sediment samples were collected from the Shelf of the East China Sea and five rivers,including Huanghe （Yellow）,Changjiang （Yangtze）,Qiantang,Ou and Min *** sediment grain size and the contents of rare earth elements （REEs） were measured with laser particle size analyzer and ICP-MS *** results show that absolute REE content （ΣREE） and the concentration ratio of light REEs to heavy REEs （l/HREE） are different in the sediments among those *** are higher REE contents in being less than 2 m and 2–31 μm fractions in the Changjiang Estuary surface *** REE contents of bulk sediment are dominated by the corresponding values of those leading *** of sediment is higher close to the estuaries and declines seaward on the inner shelf of the East China Sea （ECS）.The l/HREE ratio has a tendency of increase southward from 28 ？ *** conditions plays a predominate role on spacial distributions of the surficial sediment’s REE *** some situations,the currents tend to remove the coarser light grains from initial populations,as well as the deposit of the finer heavy mineral *** other situations,the currents will change the ratio of sediment constituents,such as ratio between silts and clays in the *** a result,the various values of REE or l/HREE ratio in different bulk sediments are more affected by the change of size-fractions than source *** the long-term stable hydrodynamic environment,i.e.,the East China Sea Shelf,new sediment transport model based on the size and density gradation concept may help to understand the spatial distribution patterns of REE parameters.

关键词： rare earth elements fingerprints East China Sea Shelf sediment transport

Structural phase transitions of tellurium nanoplates under pressure

在线全文

学校读者我要写书评

暂无评论

chinese physics B 2015年第3期24卷 280-283页

作者：李超 Arfan Bukhtiar 沈希孔盼盼王伟鹏赵豪飞姚湲邹炳锁李延春李晓东刘景靳常青禹日成 beijing National laboratory for Condensed Matter physics Institute of PhysicsChinese Academy of Sciences beijing key laboratory of Nanophotonics and Ultrafine Optoelectronic Systems Beijing Institute of Technology institute of high energy physics Chinese Academy of Sciences

In situ high-pressure angle dispersive x-ray diffraction experiments using synchrotron radiation on Te nanoplates were carried out with a diamond anvil cell at room temperature. The results show that Te-Ⅰ with a trigonal structure transforms to triclinic Te-Ⅱ at about 4.9 GPa, Te-Ⅱ transforms to monoclinic Te-Ⅲ at about 8.0 GPa, Te-Ⅲ turns to rhombohedral Te-Ⅳ at about 23.8 GPa, and Te-Ⅳ changes to body centered cubic Te-Ⅴ at 27.6 GPa. The bulk moduli B0 of Te nanoplates are higher than those of Te bulk materials.

关键词： tellurium nanoplates phase transition high pressure