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Positive elementary operators compressing spectrum

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Chinese Science Bulletin 1997年第4期42卷 270-274页

作者： Zhang, XL Hou, JC Department of Mathematics Shanxi Teachers University Linfen 041004 China

LET H be an infinite-dimensional complex Hilbert space with inner product and B(H) the von Neumann algebra of all bounded linear operators on H. For T∈B(H), σ(T), as usual, will denote the spectrum of T. Let Φ be a linear map from B(H) into itself. Φ is spectrum-preserving if σ(Φ(T))=σ(T) for all T∈B(H); Φ is spectrum-compressing

关键词： elementary operators spectrum preserver positive linear maps.

Effect of Phosphorus Level on the Availability of Some Micronutrients in a Vertic Argiudoll Soil under No-Tillage System in Argentina

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Journal of Environmental Science and Engineering(A) 2012年第2期1卷 202-208页

作者： Marcelo Beltran Emilia Rivero Gustavo Cruzate Tomas Boscot Antonio Mallarino Soil Institute National Institute of Agricultural Technology （1NTA） Castelar 1712 Argentina Department of Agronomy Iowa State University Ames Iowa 52240 USA

There are interactions between phosphorus （P） and some micronutrients which can affect their availability if P is applied as a fertilizer in high concentrations. There are many mechanisms of interactions between P and micronutrients and changes in pH values caused by phosphate fertilization is one of them. These interactions between nutrients might be more pronounced under a no-tillage system which produces stratification and accumulation of few mobile nutrients as P in the surface horizons due to the lack of soil removement. The objectives of this study were：（1） to evaluate the effect of P concentration on the availability ofCu, Zn, Fe and Mn in soil under no-tillage system; （2） to produce maps.of nutrients availability and to analyze whether an interaction between nutrients spatial distribution exists. The study was carried out in Parana, province of Entre Rios, in a soil classified as Vertic Argiudol in two consecutive growing seasons （2006 and 2007）. A plot of 1 （one） hectare under no-tillage system with a double-cropped wheat-soybean rotation in sequence （soybean sowing after wheat harvest） was sampled by the grid methods. The results of this study suggest which tillage regime and phosphate fertilization increased P levels in superficial horizons and this produced a negative relationship between micronutrients and P. Regarding the nutrients map distributions, the negative interaction between P and micronutrients was clearly seen in the case ofFe_ Mn and Zn.

关键词： Phosphorus micronutrients relationship fertilization tillage maps.

Local connectivity of the Julia set for geometrically finite rational maps

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Science China Mathematics 1996年第1期39卷 39-47页

作者：谭蕾尹永成 UMPA UMR 128 CNRS Ecole Nonnale Superieure de Lyon 46 allee d'Italie 69364 Lyon Cedex 07 France Institute of Mathematics Zhejiang University Hangzhou 310027 China

It is proved that each (eventually) periodic connected component of the Julia set of a geometrically finite rational map is locally connected.

关键词： Julia set local connectivity finite rational maps.

Generalized Landau-Lifshitz systems and harmonic maps

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Science China Mathematics 1996年第12期39卷 1242-1257页

作者：郭柏灵王友德 (Center for Nonlinear Studies Institute of Applied Physics and Computational Mathematics Beijing 100088 China) (Institute of Mathematics Chinese Academy of Sciences Beijing 100080 China)

The existence of global weak (smooth) solutions to the generalized Landau-Lifshitz systems of the ferromagnetic spin chain type from a Riemarm surface onto a unit sphere is established and some relation between harmon... 详细信息

关键词： generalized Landau-Lifshitz systems Riemannian manifold→Sn-1 harmonic maps.