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Sharpness on the Lower Bound of the lifespan of Solutions to Nonlinear Wave Equations

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Chinese Annals of Mathematics,Series B 2011年第4期32卷 521-526页

作者： Yi ZHOU 1 Wei HAN 2.1 Nonlinear Mathematical Modeling and Methods Laboratory shanghai Key Laboratory for Contem- porary Applied Mathematics school of Mathematical {2., fudan university, shanghai 2.0433, China. 2.school of Mathematical {2., fudan university, shanghai 2.0433, China Department of Mathematics, North university of China, Taiyuan 030051, China. Nonlinear Mathematical Modeling and Methods Laboratory Shanghai Key Laboratory for Contemporary Applied Mathematics School of Mathematical Sciences Fudan University Shanghai 200433 China

This paper is devoted to proving the sharpness on the lower bound of the lifespan of classical solutions to general nonlinear wave equations with small initial data in the case n = 2.and cubic nonlinearity （see the results of T. T. Li and Y. M. Chen in 1992.. For this purpose, the authors consider the following Cauchy problem： { where □=δt^2.∑i=1n δx^^2. is the wave operator, g（x）（≡/） 0 is a smooth non-negative function with compact support, and ε 〉 0 is a small parameter. It is shown that the solution blows up in a finite time, and the lifespan T（ε） of solutions has an upper bound T（ε） ≤ exp（Aε-2. with a positive constant A independent of ε, which belongs to the same kind of the lower bound of the lifespan.

关键词： Nonlinear wave equation Cauchy problem lifespan

Local Existence of Smooth Solutions to the FENE Dumbbell Model

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Chinese Annals of Mathematics,Series B 2012年第4期33卷 501-520页

作者： Ge YANG11school of Mathematical sciences,{2., shanghai 2.0433, China. school of Mathematical sciences Fudan University Shanghai 200433 China

The author proves the local existence of smooth solutions to the finite extensible nonlinear elasticity (FENE) dumbbell model of polymeric flows in some weighted spaces if the non-dimensional parameter b > 2.

关键词： Fokker-Planck equation FENE model Degenerate parabolic equations Regularity

Identification and Characterization of hmr19 Gene Encoding a Multidrug Resistance Efflux Protein from Streptomyces hygroscopicus *** Strain 10-2.

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Acta Biochimica et Biophysica Sinica 2004年第8期36卷 519-528页

作者： Lei QIN , Heng-An WANG1 , Zhong-Qin WU, Xiao-Feng ZHANG, Mei-Lei JIN,Zi-Xin DENG2. and Guo-Ping ZHAOshanghaiResearch Center of Biotechnology, shanghai Institute for Biological {2., Chinese Academy of {2.,Graduate school of the Chinese Academy of {2., shanghai 2.02.3, China 1school of Agriculture and Biology, shanghai Jiaotong university, shanghai 2.1101, China 2.4} of {12. Science and Biotechnology, shanghai Jiaotong university, shanghai 2.0030, China shanghaiResearch Center of Biotechnology Shanghai Institute for Biological Sciences Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences school of Agriculture and Biology Shanghai Jiaotong University

The hmr19 gene was cloned from Streptomyces hygroscopicus subsp. yingchengensis strain 10- 2., a bacterium strain producing agricultural antibiotics. Sequence similarity comparison indicates that hmr19 gene may encode a predicted protein with 14 putative transmembrane α-helical spanners, belonging to the drug:H+ antiporter-2.family of the major facilitator superfamily. The expression of hmr19 in the mycelium of strain 10-2. was detected by Western blotting analysis. Gene replacement technology was employed to construct an hmr19 disruption mutant. The growth inhibition test against different antibiotics indicated that the mutant strain was 5–2. fold more susceptible to tetracycline, vancomycin and mitomycin C than the parental wild type strain. The mutant took up tetracycline much faster and accumulated more antibiotics than the wild type strain 10-2.. While with the addition of an energy uncoupler, carbonyl cyanide m- chlorophenylhydrazone, the characteristics of the accumulation of [3H]tetracycline in these two strains were almost the same. It was thus concluded that hmr19 encoded a multidrug resistance efflux protein.

关键词： multidrug resistance (MDR) gene replacement (knockout) Streptomyces Streptomyces hygroscopicus subsp. yingchengensis strain 10-2.

Semantic Search among Heterogeneous Biological Databases Based on Gene Ontology

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Acta Biochimica et Biophysica Sinica 2004年第5期36卷 365-370页

作者： Shun-Liang CAO, Lei QIN1, Wei-Zhong HE1, Yang ZHONG2. Yang-Yong ZHU, and Yi-Xue LI1,3* Department of Computing and Information Technology, fudan university, shanghai 2.0433, China {2. Center for Bioinformation 1 Technology, {2. 2.02.5, China school of life {6., fudan university, shanghai 2.0433, China Bioinformation Center of {2. Institutes for Biological {6., the Chinese Academy of {6., {2. 2.0031, China Department of Computing and Information Technology Fudan University Shanghai China

Semantic search is a key issue in integration of heterogeneous biological databases. In this paper, we present a methodology for implementing semantic search in BioDW, an integrated biological data warehouse. Two tables are presented: the DB2.O table to correlate Gene Ontology (GO) annotated entries from BioDW data sources with GO, and the semantic similarity table to record similarity scores derived from any pair of GO terms. Based on the two tables, multifarious ways for semantic search are provided and the corresponding entries in heterogeneous biological databases in semantic terms can be expediently searched.

关键词： Gene Ontology semantic search BioDW

Optimal variational principle for backward stochastic control systems associated with Lévy processes

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Science China Mathematics 2012年第4期55卷 745-761页

作者： TANG MaoNing 1 & ZHANG Qi 2.1 Department of Mathematical sciences,Huzhou university,Huzhou 313000,China 2.{2. of Mathematical sciences,fudan university,{6. 2.0433,China 1. Department of Mathematical sciences Huzhou University Huzhou 313000 China2. School of Mathematical Sciences Fudan University Shanghai 200433 China

The paper is concerned with optimal control of backward stochastic differentiM equation （BSDE） driven by Teugel＇s martingales and an independent multi-dimensional Brownian motion, where Teugel＇s martingales are a family of pairwise strongly orthonormal martingales associated with L6.y processes （see e.g., Nualart and Schoutens＇ paper in 2.00）. We derive the necessary and sufficient conditions for the existence of the optimal control by means of convex variation methods and duality techniques. As an application, the optimal control problem of linear backward stochastic differential equation with a quadratic cost criteria （or backward linear-quadratic problem, or BLQ problem for short） is discussed and characterized by a stochastic Hamilton system.

关键词： stochastic control stochastic maximum principle Ldvy processes Teugel's martingales backwardstochastic differential equations

RADIAL BASIS FUNCTION INTERPOLATION IN SOBOLEV SPACES AND ITS APPLICATIONS

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Journal of Computational Mathematics 2007年第2期25卷 201-210页

作者： Manping Zhang (school of Mathematical sciences,{2. university,shanghai 2.0433,China Institute of Computational Mathematics,Chinese Academy of sciences,Beijing 100080,China school of Mathematical sciences Fudan University Shanghai 200433 China Institute of Computational Mathematics Chinese Academy of Sciences Beijing 100080 China

In this paper we study the method of interpolation by radial basis functions and give some error estimates in Sobolev space H^k（Ω）（k 〉 1）. With a special kind of radial basis function, we construct a basis in H^k（Ω） and derive a meshless method for solving elliptic partial differential equations. We also propose a method for computing the global data density.

关键词： Sobolev space Radial basis function Global data density Meshless method

A new scheme of digital communication using chaotic signals in MIMO channels

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Science China(Information sciences) 2012年第10期55卷 2183-2193页

作者： MA HuanFei 1 & KAN HaiBin 2.1 school of Mathematical sciences,Soochow {2.,Suzhou 2.5006.China 2.school of Computer Science,fudan {2.,{6. 2.0433,China 1. school of Mathematical sciences Soochow University Suzhou 215006 China 2. school of Computer Science Fudan University Shanghai 200433 China

This paper proposes a new digital communication scheme,which uses chaotic signals based on the adaptive synchronization and parameter identification technique of chaotic systems reported *** to the multi signal character,this scheme combines the chaotic signal transmission with the MIMO channel technique in a wireless environment,which is different from the traditional chaotic communication *** a practical perspective,an outline of modulation,channel model,demodulation and non-coherent detection is ***,system performance is evaluated by simulations,and improvements on this scheme are also discussed.

关键词： chaotic modulation chaotic digital communication mapping parameters MIMO channel

Hyperbolic positive mass theorem under modified energy condition

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Science China Mathematics 2008年第12期51卷 2189-2197页

作者： XIE NaQing Institute of Mathematics, school of Mathematical sciences,{2., shanghai 2.0433, China Institute of Mathematics School of Mathematical Sciences Fudan University Shanghai 200433 China

We provide two new positive mass theorems under respective modified energy conditions allowing T00 negative on some compact set for certain modified asymptotically hyperbolic manifolds. This work is analogous to Zhang... 详细信息

关键词： positive mass theorem modified energy condition modified asymptotically hyperbolic 83C40 53C2.

Metalloproteins/metalloenzymes for the synthesis of acetyl-CoA in the Wood-Ljungdahl pathway

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Science China Chemistry 2009年第12期52卷 2071-2082页

作者： ZHU XiaoFei1 & TAN XiangShi1,2.1 Department of Chemistry,fudan university,{2. 2.0433,China 2.Institutes of Biomedical sciences,fudan university,{2. 2.0433,China 1. Department of Chemistry Fudan University Shanghai 200433 China 2. Institutes of Biomedical sciences Fudan University Shanghai 200433 China

This paper focuses on the group of metalloproteins/metalloenzymes in the acetyl-coenzyme A synthesis pathway of anaerobic microbes called Wood-Ljungdahl pathway,including formate dehydrogenase (FDH),corrinoid iron sulfur protein (CoFeSP),acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH). FDH,a key metalloenzyme involved in the conversion of carbon dioxide to methyltetrahydrofolate,catalyzes the reversible oxidation of formate to carbon dioxide. CoFeSP,as a methyl group transformer,accepts the methyl group from CH3-H4 folate and then transfers it to ACS. CODH reversibly catalyzes the reduction of CO2.to CO and ACS functions for acetyl-coenzyme A synthesis through condensation of the methyl group,CO and coenzyme A,to finish the whole pathway. This paper introduces the structure,function and reaction mechanisms of these enzymes.

关键词： Wood-Ljungdahl pathway formate dehydrogenase corrinoid iron sulfur protein acetyl-CoA synthase CO dehydrogenase