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Strong uniqueness of best approximations in spaces of bounded linear operators

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Science China Mathematics 2004年第3期47卷 339-351页

作者： LI Chong HE Jinsu Department of Mathematics, Zhejiang University Hangzhou 310027, China Department of Mathematics, Zhejiang Normal University Jinhua 321004, China Department of Mathematics Zhejiang University Hangzhou China Department of Mathematics Zhejiang Normal University Jinhua China

The present paper is concerned with problems of the strong uniqueness of the best approximation and the characterization of a uniqueness element.in operator *** results on the strong uniqueness of the best approximation operatorfrom RS-sets are proved and the uniqueness element.of a sun in the compactoperator space from c0 to c0 is characterized by the strict Kolmogorov's *** recent results due to Lewicki and others are extended and improved.

关键词： best approximation operator, RS-set, sun, strong uniqueness, uniqueness element.

Nonstandard decision methods for the solvability of real polynomial equations

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Science China Mathematics 1999年第12期42卷 1251-1261页

作者：曾广兴 Department of Mathematics Nanchang University Nanchang China

For a multivariate polynomial equation with coefficients in a computable ordered field, two criteria of this equation having real solutions are given. Based on the criteria, decision methods for the existence of real zeros and the semidefiniteness of binaly polynomials are provided. With the aid of computers, these methods are used to solve several examples. The technique is to extend the original field involved in the question to a computable non-Archimedean ordered field containing infinitesimal element..

关键词： computational algebraic geometry polynomial with real coefficients solvability semidefiniteness infinitesimal element.

(Not) an element.ry question:How to mobilize the iron in the wall?

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Molecular Plant 2021年第10期14卷 1610-1611页

作者： Stephan Clemens Department of Plant Physiology and Faculty of Life Sciences:Food Nutrition and HealthUniversity of BayreuthUniversitätsstrasse 3095440 BayreuthGermany

Photosynthesis,respiration,and countless other processes are dependent on proteins that carry iron(Fe)as an essential *** Fe was recruited for biological functions early in evolution,it was an available *** Earth's at... 详细信息

关键词： element. element.ry sulfide

Numerical analysis of crack-tip fields of piezoelectric media by hybrid finite element

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Chinese Science Bulletin 1999年第11期44卷 995-1000页

作者： Ming Liu Changchun Wu Univ Sci & Technol China Dept Modern Mech Anhua 230026 Peoples R China

A hybrid model, piezoelectric P-S element. is developed for electro-elastic crack analysis. The model is used to investigate coupling crack-tip fields. The obtained numerical solutions recover the 1/r1/2 singularity, and it is in good consistence with the real ones. The results offer a valuable basis for studying the mechanism of coupling fracture.

关键词： piezoelectric media fracture hybrid finite element.

Structure and regulatory function of plant transcription factors

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Chinese Science Bulletin 2001年第4期46卷 271-278页

作者： LIU Qiang, ZHANG Guiyou & CHEN ShouyiDepartment of Biological Science and Biotechnology, Tsinghua Univorsity, Beijing 100084, China Department of Biological Science and Biotechnology, State Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China Institute of Genetics, Chinese Academy of Sciences, Beijing 100101, China Department of Biological Science and Biotechnology Tsinghua University Beijing China Department of Biological Science and Biotechnology State Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing China Institute of Genetics Chinese Academy of Sciences Beijing China

The expression of inducible genes in plants is regulated by specific transcription factors at the transcrip-tional level. A typical transcription factor usually contains a DNA-binding domain, a transcription regulation domain, a dimerization site and a nuclear localization domain. These functional domains define the characteristic, localization and regulatory role of a transcription factor. Transcription factors recognize and bind to specific cis-acting element. or interact with other proteins, and then activate or repress the transcription of target genes by their functional domains. In recent years, elucidation on the structure and function of transcription factors has become an important subject in plant molecular biology.

关键词： transcription factor DNA-binding domain cis-acting element.

Solution to Equivalent Power element.of a Six Degrees of Freedom Simulator

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Journal of Donghua University(English Edition) 2002年第3期19卷 63-67页

作者：赵强李洪人王栋梁 Mechatron. Eng. Coll. Harbin Inst. of Technol. Harbin 150001 China

The dynamical equation of a six degrees of freedom(DOF) Stewart-type simulator with load and impact force is derived. By associating the direct solution to acceleration with the inverse solution to force, an equivalent power element.model of the simulator is further presented, which offers the basis for analysis and design of the control system of the simulator.

关键词： six DOF simulator, Stewart platform, direct solution to acceleration, Newton-Euler method, power element.

A study on determining the location of groundwater divide using a mathematical morphology method

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Science China(Technological Sciences) 2006年第Z2期49卷 141-148页

作者： PAN Yun, GONG Huili, DUAN Fuzhou & HU Zhuowei Key Laboratory of 3D Information Acquisition and Application, Ministry of Education, Capital Normal University, Beijing 100037, China Key Laboratory of Resource Environment and GIS of Beijing, Capital Normal University, Beijing 100037, China Capital Normal Univ Minist Educ Key Lab D Informat Acquisit & Applicat 3 Beijing 100037 Peoples R China Capital Normal Univ Key Lab Resource Environm Beijing 100037 Peoples R China Capital Normal Univ GIS Beijing Beijing 100037 Peoples R China

Placement of a groundwater divide indicates sink areas and spatial distribution, knowledge of which helps in the mapping of regional aquifer properties and the management of groundwater resources. By applying mathematical morphology to a conceptual model of a watershed and characteristic erosion and dilation operations, this paper proposes a structuring element.with which to extract the shape and location of groundwater divide. With due consideration to watershed linearity, a structuring element.with three origins is designed to connect watershed points. After erosion, closing, and dilation operations, the groundwater divide is determined; the results indicate this method's feasibility and accuracy.

关键词： groundwater divide, mathematical morphology, structuring element.

Characterization of the classical domains by Caratheodory volume element. and Eisenman-Kobayashi volume element.

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Science China Mathematics 2003年第2期46卷 239-244页

作者：赵振刚殷慰萍 Department of Mathematics Capital Normal University

We give a sufficient and necessary condition that a domain is biholomorphic to the classical domain.

关键词： Carathèodory volume element. Eisenman-Kobayashi volume element. the classical domain.

On the Classification of AF-Algebras and Their Dimension Groups

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Chinese Science Bulletin 1993年第2期38卷 103-106页

作者：黄昭波 Institute of Mathematics Fudan University Shanghai 200433 PRC

1 Introduction The classification is an important subject in studying operator algebras. Many works have been done for the classification of Von Neumann algebras. In the last two decades, with the development of operator K-theory, more and more attention has been paid to this problem for C~*-algebras, but we have not seen any great progress for its complex

关键词： AF-algebra dimension group functional Archimedean element.