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MINIMAL INVERSION AND ITS ALGORITHMS OF DISCRETE-TIME NONLINEAR SYSTEMS

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Journal of Systems Science & Complexity 2005年第3期18卷 383-395页

作者： ZHENG Yufan Department of Electrical and Electronic engineering, The university of Melbourne, Parkville, Vic. 3010, Australia institute of Systems Science, east china normal university, shanghai 200062, china. Department of Electrical and Electronic engineering The University of Mellbourne Australia

The left-inverse system with minimal order and its algorithms of discrete-time nonlinear systems are studied in a linear algebraic framework. The general structure of left-inverse system is described and computed in s... 详细信息

关键词： left-inverse discrete-time system nonlinear system symbolic computation

FREE-SURFACE WAVES AND FAR WAKES GENERATED BY A FLOATING BODY IN A VISCOUS FLUID

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Journal of Hydrodynamics 2003年第4期15卷 10-16页

作者： Lu Dong-qiang Department of Mechanical engineering, The university of Hong Kong, Hong Kong, china shanghai institute of Applied Mathematics and Mechanics, shanghai university, shanghai 200072, china Dept. of Mech. Eng. Univ. of Hong Kong Hong Kong Hong Kong Inst. of Appl. Math. and Mech. Shanghai Univ. Shanghai 200072 China

The free-surface waves and the flow field due to a body moving on the surfaceof an incompressible viscous fluid of infinite depth were studied analytically. The floating bodywas modeled as a normal point pressure on the free surface. Based on the Oseen approximation forgoverning equations and the linearity assumption for boundary conditions, the exact solutions inintegral form for the free-surface elevation, the velocities and the pressure were given. Byemploying Lighthill's two-stage scheme, the asymptotic representations in far field for largeReynolds numbers were derived explicitly. The effect of viscosity on the wave profiles was expressedby an exponential decay factor, which removes the singular behavior predicted by the potentialtheory.

关键词： free-surface waves velocity distribution floating body viscosity asymptotic representation light-hill's two-stage scheme

Harmonic maps with potential from complete manifolds

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Chinese Science Bulletin 1998年第21期43卷 1780-1786页

作者： CHEN Qun Mathematics Department, Central china normal university, Wuhan 430079, china institute of Mathematics, Fudan university, shanghai 200433, china Mathematics Department Central China Normal University Wuhan China institute of Mathematics Fudan University Shanghai China

Harmonic maps with potential from complete manifolds are considered. This is a new kind of maps more general than the usual harmonic maps relating to many interesting problems such as equilibrium system of ferromagnetic spin chain and Neumann motion. Aiming at the general properties, the author derives basic gradient estimates and then Liouville type results for these maps, which are interesting in constrast to those of the usual harmonic maps for the presence of potentials.

关键词： harmonic maps potential ferromagnetic chain gradient estimate.

The Bedload Movement in the Changjiang Estuary

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china Ocean engineering 1993年第4期8卷 441-450页

作者： Li Jiufa, Shi Weirong, Shen Huanting Xu Haigen and Doeke Eisma Associate Professor, institute of Estuarine & Coastal Research (1ECR), east china normal university, shanghai200062 Professor, IECR, east china normal university, shanghai 200062 Professor, Netherlands institute for Sea Research, P. O. Box 59 1790 AB, Den Burg, Texel, The Netherlands institute of Estuarine & Coastal Research (IECR) East China Normal University Shanghai 200062 China

Sandwaves in the Changjiang estuary were measured with a shallow sediment profiler and an echosounder from 1978 to 1988. The data, together with grain size and bedform of sediment indicates that the bedload movement by rolling and saltation is of great significance to sediment transport and is the principal factor responsible for sandwave and sandbody development in the estuary. The sandwaves were found well-developed, which is related to the tidal range and the velocity of ebb current. However, the further growth is restricted by strong flood current prevailing in the estuary. Because of the significant bedload, the sandbodies shift obviously and frequently, and sometimes the exchange of position occurs between the sandbodies and tidal channels. As a result, ships are regularly forced to change their navigation course.

关键词： Changjiang Estuary bed load sand ripple sediment

Microfossils, carbonate lysocline and compensation depth in surface sediments of the northeastern South china Sea

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Acta Oceanologica Sinica 2003年第4期22卷 597-606页

作者： Chen Ronghua1, Xu Jian2, Meng Yi3, Wang Dongjun1 Liu Chuanlian2, Huang Baoqi2, Zhang Fuyuan1 1. Key Laboratory of Submarine Geosciences of State Oceanic Administration, Hangzhou 310012, china 2. Laboratory of Marine Geology, Tongji university, shanghai 200092, china 3. institute of Estuarine and Coastal Research, east china normal university, shanghai 200062, china Key Lab. of Submarine Geosci. State Hangzhou 310012 China Laboratory of Marine Geology Tongji University Shanghai 200092 China institute of Estuarine/Coastal Res. East China Normal University Shanghai 200062 China

Based on the quantitative analyses of abundance of planktonic foraminifera, benthic foraminifera, calcareous nannofossils, the ratios of calcareous to siliceous microfossils, and the determination of carbonate contents in the surface sediments of the northeastern South china Sea, it has been found that the carbonate contents, the abundance of planktonic foraminifera and calcareous nannoplankton, and the ratio of calcareous microfossils decrease rapidly while the ratio of the benthic foraminifera to the total foraminiferal fauna, specific value of siliceous microfossils, and the percentage of the agglutinated tests in the benthic foraminiferal fauna increase with the water depth. The results indicate that the microfossils abundance and ratio, and the carbonate content are closely related to the carbonate lysocline and carbonate compensation depth (CCD) in the study area. In addition, the carbonate lysocline and the CCD are different between the southern and northern parts of the South china Sea. Both the lysocline and the CCD are deeper in the south with 2 600 and 3 600 m than in the north with 2 200 and 3 400 m, respectively.

关键词： microfossils carbonate lysocline depth carbonate compensation depth (CCD) surface sediments South china Sea (SCS)

Identification of human dopamine D1-like receptor agonist using a cellbased functional assay

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Acta Pharmacologica Sinica 2005年第10期26卷 1181-1186页

作者： Nan JIANG~2, Ke-qing OU-YANG~3, Shao-xi CAI~3, Ying-he HU~2, Zhi-liang XU~(2,4) ~2 shanghai institute of Brain Functional Genomics and Key Lab of Brain Functional Genomics, Ministry of Education, Science and Technology Commission of shanghai Municipality, east china normal Uuiversitv, shanghai 200062 ~3 College of Bioengineering, Chongqing university, Chongqing 400044, china shanghai institute of Brain Functional Genomics and Key Lab of Brain Functional Genomics Ministry of Education Science and Technology Commission of Shanghai Municipality East China Normal University Shanghai China College of Bioengineering Chongqing University Chongqing China

Aim: To establish a cell-based assay to screen human dopamine D1 and D5 receptor agonists against compounds from a natural product compound library. Methods: Synthetic responsive elements 6xcAMP response elements （CRE） and a mini promoter containing a TATA box were inserted into the pGL3 basic vector to generate the reporter gene construct pCRE/TA/Luci. CHO cells were co-trans- fected with the reporter gene construct and human D1 or D5 receptor cDNA in mammalian expression vectors. Stable cell lines were established for agonist screening. A natural product compound library from over 300 herbs has been established. The extracts from these herbs were used for human D1 and D5 receptor agonist screenings. Results: A number of extracts were identified thatactivated both D1 and D5 receptors. One of the herb extracts, SBG492, demonstrated distinct pharmacological characteristics with human D1 and D5 receptors. The EC50values of SBG492 were 342.7 μg/mL for the D1 receptor and 31.7 μg/mL for the D5 receptor. Conclusion: We have established a cell-based assay for high-throughput drug screening to identify D1-like receptor agonists from natural products. Several extracts that can active D1-like receptors were discovered. These compounds could be useful tools for studies onthe functions of these receptors in the brain and could potentially be developed into therapeutic drugs for the treatment of central nervous system diseases.

关键词： dopamine DI receptors drug screening Chinese herbal drugs

Fredholm operators in Toeplitz algebras associated with discrete abelian groups

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Chinese Science Bulletin 1998年第14期43卷 1175-1179页

作者： XU Qingxiang 1 and CHEN Xiaoman 2 1. Department of Mathematics, shanghai normal university, shanghai 200234, china 2. Laboratory of Mathematics for Nonlinear Sciences and institute of Mathematics, Fudan university, shanghai 200433, china Department of Mathematics Shanghai Normal University Shanghai China Laboratory of Mathematics for Nonlinear Sciences and institute of Mathematics Fudan University Shanghai China

The locally finite below sets are introduced and the Fredholm operators in Toeplitz algebras associated with discrete abelian groups are studied.

关键词： discrete abelian group quasi_ordered group Toeplitz operator Fredholm operator.

Density functional theory study on the structural and electronic properties of Ag-adsorbed (MgO)_n clusters

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Science china(Physics,Mechanics & Astronomy) 2009年第5期52卷 734-741页

作者： GE GuiXian1, JING Qun1 & LUO YouHua2,3 1 Key Laboratory of Ecophysics and Department of Physics, normal College, Shihezi university, Shihezi 832003, china 2 School of Science, east china university of Science and Technology, shanghai 200237, china 3 institute for Theoretical Physics, Henan university, Kaifeng 475004, china Key Laboratory of Ecophysics and Department of Physics Normal College Shihezi University Shihezi China School of Science East China University of Science and Technology Shanghai China institute for Theoretical Physics Henan University Kaifeng China

Equilibrium geometries, charge distributions, stabilities and electronic properties of the Ag-adsorbed (MgO)n (n = 1-8) clusters have been investigated by density functional theory (DFT) with generalized gradient approximation (GGA) for exchange-correlation functional. The results show that hollow site is energetically preferred for n≥4, and the incoming Ag atoms tend to cluster on the existing Ag cluster. The Mulliken populations indicate that the interaction between the Ag atom and Magnesia clusters is mainly induced by a weak atomic polarization. The adsorbed Ag atom only causes charge redistributions of the atoms near itself. The effect of the adsorbed Ag atom on the bonding natures and structural features of Magnesia clusters is minor. Furthermore, the investigations on the first energy difference, fragmentation energies and electron affinities show that the Ag(MgO)4 and Ag(MgO)6 are the most stable among studied clusters.

关键词： Ag (MgO)_n clusters geometries electronic properties

Experimental Study of Motion of Nitrogen Taylor Bubbles and Liquid Slugs in Inclined Tubes

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Chinese Journal of Aeronautics 2009年第4期22卷 349-354页

作者： Zhang Hua,Wang Shuhua,Wang Jing institute of engineering Thermo-physics,shanghai Jiao Tong university,shanghai 200240,china institute of engineering Thermo-physics Shanghai Jiao Tong University Shanghai 200240 China

This article studies rising velocity of Taylor bubbles and liquid slugs in liquid nitrogen at different axial positions in upward inclined tubes by means of a high speed motion analyzer. The bottom-closed tubes in the experiments are 1.0 m long with an inner diameter of 0.014 m or 0.018 m. The tube inclines upward from 0~ to 50~ with respect to the normal. Statistical method is used to analyze the data of the Taylor bubble and the liquid slug velocity. Reflecting the effects of the inclination angle on the rising velocity of Taylor bubbles and liquid slugs, the experimental results indicate the similar trend the Taylor bubble velocity and the liquid slug velocity have： it increases first, and then decreases with the increase of the inclination angle. Moreover, with the increase of the inclination angle, the liquid slug velocity becomes greater than Taylor bubble velocity.

关键词： cryogenic two-phase flow rising velocity high speed motion analyzer liquid nitrogen Taylor bubble liquid slug inclined tube