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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.

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.

Superconductivity of small metal grains

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Science china.Physics,Mechanics & Astronomy) 2005年第4期48卷 431-441页

作者： ZHENG Renrong1 chen Zhiqian2 & ZHU Shunquan1,3 1. department of Physics, shanghai normal university, shanghai 200234, china.2. department of Physics, Southwest normal university, Chongqing 400715, china.3. department of Computer and Electric Technology, shanghai Business School, shanghai 201400, china department of Physics Shanghai Normal University Shanghai China department of Physics Southwest Normal University Chongqing China department of Computer and Electric Technology Shanghai Business School Shanghai China

The formulas of the energy gap and superconducting critical temperature appropriate for systems with both odd and even number of electrons are derived; the bases of the derivations are BCS theory and energy level statistics. Numerical results qualitatively agree with the experimental phenomena. i.e., the superconductivity of small metallic grains will first enhance then decrease to zero when the grain are getting smaller and smaller. The calculations indicate that the above phenomena happen in the metallic grains belonging to Gaussian Orthogonal Ensemble (GOE) and Gaussian Unitary ensemble (GUE) with zero spin; The superconductivity of small metallic grains in Gaussian Symplectic Ensemble (GSE) will monotonically decrease to zero with the decreasing of the grain size. The analyses suggest that the superconductivity enhancements come from pairing and the balance of the strengths between spin-orbital coupling and external magnetic field. In order to take the latter into account, it is necessary to include the level statistics given by Random Matrix Theory (RMT) in describing small metallic grains.

关键词： size effect, superconductivity enhancements, small metallic grains.

A Note on Schwarz-Pick Estimate

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Chinese Annals of mathematics,Series B 2010年第3期31卷 343-346页

作者： Yang LIU Zhihua chen department of mathematics Zhejiang Normal University Jinhua 321004 Zhejiang China. department of mathematics Tongji University Shanghai 200092 China

A Schwarz-Pick estimate of higher order derivative for holomorphic functions with positive real part on Bn is presented. This improves the earlier work on Schwarz-Pick estimate of higher order derivatives for holomorp... 详细信息

关键词： Schwarz-Pick estimate Holomorphic function Taylor expansion

A NOTE ON THE RELATIVE CANONICAL IMAGE OF A NON-HYPERELLIPTIC FIBRATION OF GENUS

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Chinese Annals of mathematics,Series B 1994年第2期15卷 157-164页

作者： chen ZHIJIE(department of Matehematics,East normal university, shanghai 00062, china. E china.normal UNIV DEPT MATHSHANGHAI 200062PEOPLES R CHINA

This paper investigates the relative 1-canonical images of non-hyperelliptic fibrations of genus 4. It is proved that if a fibre of the relative 1-canonical image ∑ is not a complete intersection in 3 , then the var... 详细信息

关键词： Genus Non-hyperelliptic fibration Canonical image Algebraic variety.

Schwarz-Pick estimates for positive real part holomorphic functions on unit ball and polydisc

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Science china.mathematics 2010年第4期53卷 1017-1024页

作者： LIU Yang 1,& chen ZhiHua 2 1 department of mathematics,Zhejiang normal university,Jinhua 321004,china.2 department of mathematics,Tongji university,shanghai 200092,china department of mathematics Zhejiang Normal University Jinhua China department of mathematics Tongji University Shanghai China

We give higher order derivatives Schwarz-Pick estimates for all positive real part holomorphic functions on Bn and D n,and generalize early work on Schwarz-Pick estimate of higher order derivatives for holomorphic fun... 详细信息

关键词： Schwarz-Pick estimate holomorphic function Taylor expansion

SCHWARZ-PICK ESTIMATES FOR BOUNDED HOLOMORPHIC FUNCTIONS ON CLASSICAL DOMAINS

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Acta Mathematica Scientia 2011年第4期31卷 1377-1382页

作者：刘洋陈志华 department of mathematics Zhejiang Normal University department of mathematics Tongji University

In this paper, Schwarz-Pick estimates for high order Fr′echet derivatives of bounded holomorphic functions on three kinds of classical domains are presented. We generalize the early work on Schwarz-Pick estimates of ... 详细信息

关键词： Schwarz-Pick estimate holomorphic functions classical domains

Impact on the Yangtze (Changjiang) Estuary from its drainage basin: Sediment load and discharge

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Chinese Science Bulletin 2001年第S1期46卷 73-80页

作者： chen Zhongyuan & ZHAO YiwenState Key Laboratory for Estuarine and Coastal Research, East china.normal university, shanghai 200062, china.department of Geography, East china.normal university, shanghai 200062, china State Key Laboratory for Estuarine and Coastal Research East China Normal University Shanghai China department of Geography East China Normal University Shanghai China

This paper focuses on the sediment transport and freshwater discharging from upper Yangtze drainage basin downstream, primarily on the basis of multiyear hy-drological data collected from three major hydrological gauge stations (Yichang, Hankou and Datong). Data indicate highest sediment load in Yichang (5.6×108 t/a), lowest in Hankou (5.1×108t) and second highest in Datong (5.4×108 t). This fluctuations are identical with what has been observed from the annual flood season. About one thirds of the sediment load are trapped in the middle Yangtze River course, where meandering river pattern prevails; rest of them are directly transported to the river mouth area via lower Yangtze River channel, where the river is typically confined by the exposed base rock and almost none is being trapped, instead, minor being drained to the mainstream from the local tributaries. To recognize this sediment delivery and river flow media is vital, because it can highlight morphologic/topographic correlation between the

关键词： sediment load discharge estuarine impact the Yangtze River.

Effect of osmotic shock on the redox system in plasma membrane of Dunaliella salina

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Cell Research 1996年第1期6卷 31-38页

作者： chen SI XUE CHI CHIONG YEN XIN ZHI JIAO (Institute of Plant Physiology, Chinese Academy of Sciences, shanghai 200032, china.)(Biology department, East china.normal university,shanghai 200062, china.) Institute of Plant Physiology Chinese Academy of Sciences Shanghai China Biology department East China Normal University Shanghai China

The unicellular halotolerant alga Dunaliella salina had the ability to oxidize NADH and reduce Fe(CN)63-. The redox reactions were to some extent stimulated by slight hyperosmotic shock (2.0 mol/L → 2.6 mol/L NaCl), butmarkably inhibited by abrupt hyperosmotic shock (2.0mol/L → 3.5 mol/L NaCl) and hypoosmotic shock (2.0mol/L → 1.0 mol/L NaCl; 2.0 mol/L→0.67 mol/L NaCl).With the adaptation of algal cells to osmotic shock by accumulating or degrading intracellular glycerol, the plasmalemma redox activities were also restored. The O2 uptake stimulated by NADH could be promoted by FA and SHAM. Hypoosmotic shock increases the basal respiration rate of alga cells, but weakened the stimulating effects of NADH, FA and SHAM on O2 uptake. On the other hand, hyperosmotic shock reduced the basal respiration rate, but relatively enhanced the above effects of NADH, FA and SHAM. H+ extrusion of alga cells was inhibited by NADH and stimulated by Fe(CN)63- Vanadate and DES could inhibit H+ efflux, but had little effect in the presence of NADH and Fe(CN)63-. Both hyperand hypoosmotic shock stimulated H+ extrusion. This effect could be totally inhibited by vanadate and DES, but almost unaffected by 8-hydroxyquinoline. It was suggested that H+-ATPase probably played a more important role in H+ extrusion and osmoregulation under the conditions of osmotic shock.

关键词： Osmotic shock Dunaliella salina plasmalemma redox system