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On generalized k-syzygy modules

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Science china Mathematics 2007年第5期50卷 675-682页

作者： Chong-hui HUANG & Zhao-yong HUANG Department of Mathematics, nanjing university, nanjing 210093, china College of Mathematics and Physics, Nanhua university, Hengyang 421001, china Department of Mathematics Nanjing University Nanjing China College of Mathematics and Physics Nanhua University Hengyang China

In this paper, we first introduce the notion of generalized k-syzygy modules, and then give an equivalent characterization that the class of generalized k-syzygy modules coincides with that ofω-k-torsionfree modules. We further study the extension closure of the category consisting of generalized k-syzygy modules. Some known results are obtained as corollaries.

关键词： generalized k-syzygy module ω-k-torsionfree module extension closure

IR STUDY ON MONOMOLECULAR PARTICLE AGGLOMERATES OF POLYSTYRENE OBTAINED BY FREEZE-DRYING OF ITS DILUTE SOLUTION

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Chinese Journal of Polymer Science 2002年第4期20卷 381-383页

作者： Song Wang Qing-hua Wang Rong-shi Cheng Research Center of Materials Beijing Institute of Technology Beijing 100081, china Department of Chemistry nanjing university nanjing 210093, china Research Center of Materials Beijing Institute of Technology 北京 100081 Department of Chemistry Nanjing University Nanjing 210093

The monomolecular particle agglomerates of polystyrenes were obtained by freeze-drying of its very dilute solutions of 1.3 x 10(-5)-2.0 x 10(-5) g/mL in benzene:cylcohexane (100:1) solvents, and they were annealed at room temperature for hundred days before use. According to C-13-NMR measurement the polystyrenes should be practically atactic. The number average molecular weights of the samples are 2.80 x 10(3), 2.00 x 10(4), and 1.55 x 10(6), respectively. The freeze-dried aPS with a molecular weight higher than 10(4) show two new IR absorption bands at 1098 and 1261 cm(-1), which are absent in the normal aPS and freeze-dried styrene oligomer. It was also found that the low molecular weight samples can only form powders, whereas the freeze-dried aPS with higher molecular weight form a mixture of powders and fibrils, of which the longer fibrils show a much stronger 1261 cm(-1) band than the shorter fibrils and the powder. It seems that the 1261 cm(-1) band corresponds to the stacking behavior of monomolecular particles.

关键词： monomolecular particles atactic polystyrene FTIR spectroscopy

Constraint on the counter-jet emission in gamma-ray burst afterglows from GRB 980703

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 259-261页

作者： WANG Xin,HUANG YongFeng & KONG SiWei Department of Astronomy,nanjing university,nanjing 210093,china Department of Astronomy Nanjing University Nanjing China

We present a numerical investigation of emission from the receding jet of gamma-ray *** is found that the peak time of the receding jet emission is significantly affected by synchrotron self-absorption in radio ***,the receding jet component is generally very *** is observable mainly for those nearby events in a dense *** GRB 980703 has been observed in radio wavelengths for more than 1000 days,we argue that the receding jet emission still has not been detected for this ***,it is completely submerged by the host galaxy.

关键词： gamma rays:bursts ISM:jets and outflows methods:numerical

Interfacial Tunnel-type GMR in Granular PerovskiteLa_(1-x)Sr_xMnO_3

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Journal of Materials Science & Technology 1999年第4期15卷 373-374页

作者： Ning ZHANG and Minyu ZENG(Department of Physics, nanjing Normal university, nanjing 210097, china)WeiPing DING, Wei ZHONG and Youwei DU(National Laboratory of Solid State Microstructures, nanjing university, nanjing 210093, china)To whom correspondence sh Department of Physics Nanjing Normal University Nanjing 210097 China National Laboratory of Solid State Microstructures Nanjing University Nanjing 210093 China

The spin-dependent intedecial tunneling and the corresponding tunnef-type magnetoresistance (TMR) have been observed in granular perovskite La_(1-x)Sr_xMnO_3 with x from 0.05 to *** shows that the intedecial tunneling originates from the magnetic difference between thegrain core and the sudece, and the TMR stems from the field-induced change of magnetic orderin the interface.

关键词： Sr x)SrxMnO3 MnO GMR Interfacial Tunnel-type GMR in Granular PerovskiteLa type

The Blow-up of Solutions for Two-Dimensional Irrotational Compressible Euler Equations

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Acta Mathematica Sinica,English Series 2001年第2期17卷 217-228页

作者： Hui Cheng YIN Qin ZHENG Shu Ze JIN Department of Mathematics, nanjing university. nanjing 210093, P. R. china Department of Mathematics Nanjing University Nanjing 210093 P. R. China

For two-dimensional irrotational compressible Euler equations with initial data where that is a small perturbation from a constant state, we prove that the first-order derivatives of ρ, υ blow-up at the blow-up time... 详细信息

关键词： Lifespan Commutator method Nash-Moser iteration.

LIMIT CYCLES AND BIFURCATION CURVES FOR THE QUADRATIC DIFFERENTIAL SYSTEM (III)_(m=0) HAVING THREE ANTI-SADDLES (I)

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Chinese Annals of Mathematics,Series B 1996年第2期17卷 167-174页

作者： YE YANQIAN Department of Mathematics, nanjing university, nanjing 210008, china. 南京大学数学系江苏南京

For the quadratic system: x=-y+δx + lx2 + ny2, y=x(1+ax-y) under conditions -10 the author draws in the (a, ()) parameter plane the global bifurcationdiagram of trajectories around O(0,0). Notice that when na2+l < 0 ... 详细信息

关键词： Quadrtic systen Anti-saddle Bifurcation curve Limit cycle

A COLUMN RECURRENCE ALGORITHM FOR SOLVING LINEAR LEAST SQUARES PROBLEM

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Journal of Computational Mathematics 1996年第4期14卷 301-310页

作者： J.X. Zhao(Department of Mathematics, nanjing university, nanjing china) 南京大学数学系江苏南京

A new column recurrence algorithm based on the classical Greville method and modified Huang update is proposed for computing generalized inverse matrix and least squares solution. The numerical results have shown the ... 详细信息

关键词： Math A COLUMN RECURRENCE ALGORITHM FOR SOLVING LINEAR LEAST SQUARES PROBLEM ABS

ω-Gorenstein injective modules and dimensions

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Science china Mathematics 2011年第3期54卷 421-436页

作者： ZHU HaiYan1,2 & DING NanQing3 1Department of Mathematics, Zhejiang university, Zhejiang 310027, china 2Department of Mathematics, Zhejiang university of Technology, Zhejiang 310023, china 3Department of Mathematics, nanjing university, nanjing 210093, china Department of Mathematics Zhejiang University Zhejiang China Department of Mathematics Zhejiang University of Technology Zhejiang China Department of Mathematics Nanjing University Nanjing China

Gorenstein injective modules and dimensions have been studied extensively by many authors. In this paper, we investigate Gorenstein injective modules and dimensions relative to a Wakamatsu tilting module.

关键词： Wakamatsu tilting module ω-Gorenstein injective module ω-Gorenstein injective dimension cotilting module

FERROMAGNETIC RESONANCE STUDIES OF Co/CoFe_2O_4 MULTILAYERS

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Acta Metallurgica Sinica(English Letters) 1999年第2期12卷 181-184页

作者： B.X. Gu(Department of Physics, nanjing university, nanjing 210093, china)H. Wang(Department of Physics, Southeastern university, nanjing 210008, china)Manuscript receivedin revised form 12 October 1998) nanjing Univ Nanjing China

The Co/CoFe2O4 multilayers have been grown on the glass substrate using sputtering techniques. In these films the Co layers were measured to have the fcc structure with [11] axis perpendicular to the film plane, and the CoFe2O4 layers are amorphous. Ferromagnetic resonance measurements have been made as a function of the external magnetic field orientation in a plane perpendicular to the film. The effective magnetization, effective anisotropy constant and interface anisotropy constant have been determined. The influence of Co layers thickness on magnetic properties was discussed.

关键词： Co/CoFe_2O_4 multilayer ferromagnetic resonance magnetic property