检索结果-南通市图书馆

MULTIVARIATE FOURIER SERIES OVER A CLASS OF NON TENSOR-PRODUCT PARTITION DOMAINS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2003年第1期21卷 53-62页

作者： Jiachang Sun(Parallel Computing Division, institute of Software, chinese academy of Sciences, {3. 100080, china) Parallel Computing Division Institute of Software Chinese Academy of Sciences 北京 100080

This paper finds a way to extend the well-known Fourier methods, to so-called n+1 directions partition domains in n-dimension. In particular, in 2-D and 3.D cases, we study Fourier methods over 3.direction parallel hexagon partitions and 4-direction parallel parallelogram dodecahedron partitions, respectively. It has pointed that, the most concepts and results of Fourier methods on tensor-product case, such as periodicity,orthogonality of Fourier basis system, partial sum of Fourier series and its approximation behavior, can be moved on the new non tensor-product partition case.

关键词： Multivariate Fourier methods Non tensor-product partitions Multivariate Fourier series

Analysis of tandem repeats in the genome of chinese shrimp Fenneropenaeus chinensis

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2005年第14期50卷 1462-1469页

作者： KONG Jie1 & GAO Huan2,3.1. Key Laboratory for Sustainable Utilization of Marine Fisheries Re- sources, Ministry of Agriculture, Yellow Sea Fisheris Research Insti- tute, chinese academy of Fishery Sciences, Qingdao 266071, china 2. {3. of Oceanology, chinese academy of Sciences, Qingdao 266071, china 3. The Graduate School of the chinese academy of Sciences, beijing 10003., china Key Laboratory for Sustainable Utilization of Marine Fisheries resources Ministry of Agriculture Yellow Sea Fisheris Research Institute Chinese Academy of Fishery Sciences Qingdao China institute of Oceanology Chinese Academy of Sciences Qingdao China The Graduate School of the chinese academy of Sciences Beijing China

Through random sequencing, we found a total of 884000 base-pairs (bp) of random genomic sequences in the genome of chinese shrimp (Fenneropenaeus chinensis). Using bio-soft Tandem Repeat Finder (TRF) software, 2159 tandem repeats were found, in which there were 1714 mi- crosatellites and 445 minisatellites, accounting for 79.4% and 20.6% of repeat sequences, respectively. The cumulative length of repeat sequences was found to be 116685 bp, ac- counting for 13.2% of the total DNA sequence; the cumula- tive length of microsatellites occupied 9.78% of the total DNA sequence, and that of minisatellites occupied 3.42%. In decreasing order, the 20 most abundant repeat sequence classes were as follows: AT (557), AC (471), AG (274), AAT (92), A (56), AAG (28), ATC (27), ATAG (27), AGG (18), ACT (15), C (11), AAC (11), ACAT (11), CAGA (10), AGAA (9), AGGG (7), CAAA (7), CGCA (6), ATAA (6), AGAGAA (6). Dinucleotide repeats, not only in the aspect of the number, but also in cumulative length, were the preponderant repeat type. There were few classes and low copy numbers of repeat units of the pentanucleotide repeat type, which included only three classes: AGAGA, GAGGC and AAAGA. The classes and copy numbers of heptanucleotide, eleven-nucleotide and thirteen-nucleotide primer-number-composed repeats were distinctly less than that of repeat types beside them.

关键词：虾遗传特性遗传基因 DNA

An improved method for evaluating the seasonal variability of total suspended sediment flux field in the Yellow and East china Seas

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2011年第1期26卷 1-14页

The suspended sediment flux field in the Yellow and East china Seas(YECS) displays its seasonal variability.A new method is introduced in this paper to obtain the flux field via retrieval of ocean color remote sensing data,statistical analysis of historical suspended sediment concentration data,and numerical simulation of three-dimensional(3.) flow *** components of the sediment flux field include(i) surface suspended sediment concentration inverted from ocean color remote sensing data;(ii) vertical distribution of suspended sediment concentration obtained by statistical analysis of historical observation data;and(iii) 3. flow field modeled by a numerical *** the improved method,the 3. suspended sediment flux field in the YECS has been *** comparison with the suspended sediment flux field solely based on the numerical simulation of a suspended sediment transport model,the suspended sediment flux field obtained by the improved method is found to be more *** 3. suspended sediment flux field from ocean colour remote sensing and in situ observation are more closer to the ***,by quantitatively analyzing the newly obtained suspended sediment flux field,the quantity of sediment erosion and deposition within the different regions can be *** sediment exchange between the Yellow Sea and the East china Sea can be *** mechanism of suspended sediment transport in the YECS can be better *** particular,it is suggested that the long-term transport of suspended sediment is controlled mainly by the circulation pattern,especially the current in winter.

关键词： Suspended sediment flux field Seasonal variability Yellow and East china Seas Regression equation Numerical simulation

Application of asymptotic waveform approximation technique to hybrid FE/BI method for 3. scattering

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 in china(Series F) 2007年第1期50卷 124-134页

作者： PENG Zhen1,2,3.& SHENG XinQing2 1 institute of Electronics, chinese academy of Sciences, {3. 100080, china 2 Department of Electronic Engineering, {3. institute of Technology, {3. 100081, china 3.Graduated University of chinese academy of Sciences, beijing 10003., china 1. institute of Electronics Chinese Academy of Sciences Beijing 100080 China 2. Department of Electronic Engineering Beijing Institute of Technology Beijing 100081 China 3. Graduated University of chinese academy of Sciences Beijing 100039 China

The asymptotic waveform evaluation （AWE） technique is a rational function approximation method in computational mathemetics, which is used in many appllcations in computational electromagnetlca. In this paper, the performance of the AWE technique in conjunction with hybrid finite element/boundary integral （FE/BI） method is firstly Inveetlgeted. The formuletlon of the AWE applied in hybrid FE/BI method is given in detail. The characteristic implementation of the application of the AWE to the hybrid FE/BI method is discussed. Numarlcel results demonstrate that the AWE technique can greatly speed up the hybrid FE/BI method to acquire wide-band and wide-angle backecatter radar-cross-section （RCS） by complex targets.

关键词： hybrid FE/BI AWE electromagnetic scattering RCS

Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2,ZHANG Lei1,3.& XU JianZhong1,2 1 institute of Engineering Thermophysics,chinese academy of Sciences,{3. 100190,china 2 Key Laboratory of Wind Energy Utilization,chinese academy of Sciences,{3. 100190,china 3.Graduate School of chinese academy of Sciences,{3. 100190,china 1. institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China2. Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing 100190 China3. Graduate School of Chinese Academy of Sciences Beijing 100190 China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2-250 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge

Inertial theory of the mean Hadley circulation under the condition of nonstatic equilibrium

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第5期49卷 546-553页

作者： CHAO Jiping1 & LIU Fei2,3.1. National Marine Environmental Forecasting Center, beijing 100081, china 2. Key Laboratory Regional Climate-Environment for Temperate East Asia, institute of Atmospheric Physics, {3. academy of Sciences, beijing 100029, china 3. Graduate University of {3. academy of Sciences, beijing 100049, china 1. National Marine Environmental Forecasting Center Beijing 100081 China 2. Key Laboratory Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 3. Graduate University of chinese academy of Sciences Beijing 100049 China

Tropical atmosphere is divided into two layers, the layer near the ground is the planet boundary layer, where the motion is linear, if the radiation equilibrium temperature is given at the top of the boundary layer, the vertical motion there can be obtained. It is the non-viscous ideal atmos- pheric layer above the boundary one, where the motion is nonlinear. After getting the conservation laws of angular momentum, potential temperature and potential vortex, the inertial theory of the Hadley circulation driven by the vertical motion of the boundary layer is established, followed by sev- eral examples of its application.

关键词： Hadley circulation, inertial theory, conservation laws of angular momentum, potential temperature and potential vortex.

Transformations and non-degenerate maps

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2005年第z1期48卷 195-205页

作者： LI Baokui & WANG Yuefei institute of Mathematics, academy of Mathematics and System Sciences, chinese academy of Sciences, beijing 100080, china Graduate School, chinese academy of Sciences, beijing 100080, china 1. institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences 100080 Beijing China 2. Graduate School Chinese Academy of Sciences 100080 Beijing China

We shall prove the equivalences of a non-degenerate circle-preserving map and a M(o)bius transformation in ^Rn, of a non-degenerate geodesic-preserving map and an isometry in Hn of a non-degenerate line-preserving map and an affine transformation in Rn. That a map is non-degenerate means that the image of the whole space under the map is not a circle, or geodesic or line respectively. These results hold without either injective or surjective, or even continuous assumptions, which are new and of a fundamental nature in geometry.

关键词： M(o)bius transformation, circle-preserving map, non-degenerate map.

Uncertainty in magnetic activity indices

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2008年第10期51卷 1659-1664页

作者： XU WenYao institute of Geology and Geophysics, chinese academy of Sciences, {3. 100029, china institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Magnetic activity indices are widely used in theoretical studies of solar-terrestrial coupling and space weather prediction. However, the indices suffer from various uncertainties, which limit their application and even mislead to incorrect conclu-sion. In this paper we analyze three most popular indices, Kp, AE and Dst. Three categories of uncertainties in magnetic indices are discussed: "data uncertainty" originating from inadequate data processing, "station uncertainty" caused by in-complete station covering, and "physical uncertainty" stemming from unclear physical mechanism. A comparison between magnetic disturbances and related indices indicate that the residual Sq will cause an uncertainty of 1―2 in K meas-urement, the uncertainty in saturated AE is as much as 50%, and the uncertainty in Dst index caused by the partial ring currents is about a half of the partial ring cur-rent.

关键词： magnetic activity indices Kp AE Dst solar-terrestrial coupling space weather

Variation properties of ionospheric eclipse factor and ionospheric influence factor

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第6期15卷 573-576页

作者： ZHAO Chunmei 1,2 *, YUAN Yunbin1, OU Jikun1 and CHEN Jinping3.1. institute of Geodesy and Geophysics, chinese academy of Sciences, Wuhan 43.077,{3. 2. Graduate School of chinese academy of Sciences, beijing 10003.,{3. 3. Department of Precision Instrument and Mechanology, Tsinghua University, beijing 100084,{3.) institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Graduate School of chinese academy of Sciences Beijing 100039 China Department of Precision Instrument and Mechanology Tsinghua University Beijing 100084 China

The concepts and calculation methods of ionospheric eclipse factor (IEF) and ionospheric influence factor (IFF) are further illustrated. The temporal and spacial variation properties of IEF and IFF are studied, which shows that the properties are influenced by the geographic position and season. The possibility of improving the precision of using GPS data to determine ionospheric delay based on the above variation properties is also analysed.

关键词： GPS ionospheric eclipse factor ionospheric influence factor