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Monomial Hopf algebras over fields of positive characteristic

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science c.ina mathematics 2006年第3期49卷 320-329页

作者： LIU Gongxiang & YE Yu Institute of mathematics, Academy of mathematics and Systems science, chinese Academy of sciences, Beijing 100080, c.ina department of mathematics, university of science and technology of c.ina, hefei 230026, c.ina Institute of mathematics Academy of Mathematics Systems science Chinese Academy of Sciences Beijing 100080 China department of mathematics University of Science technology of c.ina Hefei 230026 China

In this paper, we study the structures of monomial Hopf algebras over a field of positive characteristic. A necessary and sufficient condition for the monomial coalgebra cd(n) to admit Hopf structures is given here, and if it is the case, all graded Hopf structures on cd(n)are completely classified. Moreover, we construct a Hopf algebras filtration on cd(n) which will help us to discuss a conjecture posed by Andruskiewitsch and Schneider. Finally combined with a theorem by Montgomery, we give the structure theorem for all monomial Hopf algebras.

关键词： monomial coalgebra, Gaussian binomial coefficient, monomial Hopf algebra.

On the Isometric Minimal Immersion into a Euclidean Space

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Acta Mathematica Sinica,English Series 1999年第4期15卷 555-560页

作者： Qing chen department of mathematics,The university of science and technology of c.ina,hefei 230026,P.R.c.ina E-mail:qchen@*** department of mathematics The University of Science and Technology of China Hefei P. R. China

We study the volume growth of the geodesic balls of a minimal submanifold in a Euclidean space.A necessary condition for the isometric minimal immersion into a Euclidean space is obtained. A classification of non-posi... 详细信息

关键词： Minimal immersion Geodesic ball Volume growth Ruled submanifolds

A cHARAcTERISTIc-BASED FINITE VOLUME ScHEME FOR SHALLOW WATER EQUATIONS

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Journal of Hydrodynamics 2009年第4期21卷 531-540页

作者： GUO Yan LIU Ru-xun DUAN Ya-li LI Yuan department of mathematics University of Science and Technology of China Hefei 230026 China department of mathematics China University of Mining and Technology XuZhou 221116 China

We propose a new characteristic-based finite volume scheme combined with the method of central Weighted Essentially Non-Oscillatory （cWENO） reconstruction and characteristics, to solve shallow water equations. We apply the scheme to simulate dam-break problems. A number of challenging test cases are considered, such as large depth differences even wet/dry bed. The numerical solutions well agree with the analytical solutions. The results demonstrate the desired accuracy, high-resolution and robustness of the presented scheme.

关键词： shallow water equations finite volume method characteristic method central Weighted Essentially Non-Oscillatory (cWENO) scheme HLLc flux

SYNTHESIS AND cHARAcTERIZATION OF FOUR-ARMED BLOcK POLY(STYRENE-b-p-NITROPHENYL METHAcRYLATE)PREPARED BY THE ATRP METHOD

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chinese Journal of Polymer science 2002年第4期20卷 353-360页

作者： cai-yuan Pan Lei Tao Ye Liu department of Polymer science and Engineering university of science and technology of c.ina, hefei 230026 c.ina department of Polymer science and Engineering University of Science and Technology of China Hefei 230026

A novel tetrafunctional initiator, c [cH_2O (cH_2)_3 OOccH(Br)cH_3]_4 (1), was synthesized through the reaction oftetraol with α-bromopropionyl chloride, and then was used as initiator of atom transfer radical polymerization (ATRP) in thepreparation of 4-armed polystyrene (PSt) with narrow polydispersity. The structure, molecular weight and molecular weightdistribution (MWD) of each arm were studied by ~1H-NMR and GPc data of hydrolyzed products of the 4-armed PSt. TheATRP of St using 1/cuBr/bpy as initiator system is of 'living' character based on the following evidence: narrow MWD,constant concentration of chain radical during the polymerization, control of molecular weight by the molar ratio of monomerconsumed to 1. The 4-armed poly(St-b-p-nitrophenyl methacrylate) [poly(St-b-NPMA)] was prepared by the ATRP ofNPMA using 4-armed PSt with terminal bromine as the initiator, and characterized by FT-IR, ~1H-NMR spectra and GPccurves. The micelles with PSt as core, and PNPMA as shell were formed by dropping DMSO into a solution of 4-armedpoly(St-b-NPMA) in DMF, as proved by laser light scatter (LLS) method.

关键词： Tetrafunctional initiator Atom transfer radical polymerization 4-Armed polystyrene 4-Armed poly(styrene-b-pnitrophenyl methacrylate) Unimolecular micelles

Howe duality in Dunkl superspace

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science c.ina mathematics 2010年第12期53卷 3153-3162页

作者： REN GuangBin 1,2 1 department of mathematics, university of science and technology of c.ina, hefei 230026, c.ina 2 department of mathematics, university of Aveiro, Aveiro 3810-193, Portugal 1. department of mathematics University of Science and Technology of China Hefei 230026 China2. Department of Mathematics University of Aveiro Aveiro 3810-193 Portugal

In the framework of superspace in clifford analysis for the Dunkl version, the Fischer decomposition is established for solutions of the Dunkl super Dirac operators. The result is general without restrictions on multiplicity functions or on super dimensions. The Fischer decomposition provides a module for the Howe dual pair G × osp(1|2) on the space of spinor valued polynomials with G the coxeter group, while the generators of the Lie superspace reveal the naturality of the Fischer decomposition.

关键词： Dunkl operators superspace Fischer decomposition Dirac operator

REAcTION MEcHANISM OF BENZOPHENONE-PHOTOINITIATED cROSSLINKING OF POLYETHYLENE

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chinese Journal of Polymer science 2002年第4期20卷 291-307页

作者： Bao-jun Qu State Key Laboratory of Fire science and department of Polymer science and Engineering university of science and technology of c.ina hefei 230026 c.ina Univ Sci & Technol c.ina State Key Lab Fire Sci Hefei 230026 Peoples R China Univ Sci & Technol c.ina Dept Polymer Sci & Engn Hefei 230026 Peoples R China

The radical intermediates, the crosslink microstructures, and the reaction mechanism of benzophenone (BP)-photoinitiated crosslinking of low-density polyethylene (LDPE) and model compounds (MD) have been reviewed in detail. The spin-trapping electron spin resonance (ESR) spectra obtained from the LDPE/BP systems with spin-trap agents show that two kinds of polymer radical intermediates are mainly formed: tertiary carbon and secondary carbon radicals. The spin-trapping ESR studies of MD/BP systems give further evidence that photocrosslinking reactions of PE predominantly take place a sites of tertiary carbon, secondary carbon, and especially allylic carbon when available. The high resolution c-13-NMR spectra obtained from LDPE and MD systems show that the crosslink microstructures have H- and Y-type links and that their concentrations are of the same order. The fluorescence, ESR, c-13 and H-1-NMR spectra from the PE and MD systems demonstrate that the main photoreduction product of BP (PPB) is benzpinacol formed by the recombination of two diphenylhydroxymethyl (K-.) radical intermediates. Two new PPB products: an isomer of benzpinacol with quinoid structure, 1-phenylhydroxymethylene-4-diphenylhydroxymethyl-2,5-cyclobexadiene and three kinds of alpha-alkyl-benzhydrols have been detected and identified. These results provide new experimental evidence for elucidating the reaction mechanism in the BP-photoinitiated crosslinking of polyethylene.

关键词： photocrosslinking mechanism polymer radical intermediates crosslink microstructures photolytic products of benzophenone polyethylene model compound

MONOTONE cOUPLING AND STOcHASTIc ORDERING OF ORDER STATISTIcS

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Systems science and Mathematical sciences 1995年第3期8卷 209-214页

作者： HU Taizhong(department of mathematics, university of science and technology of c.ina, hefei 230026, c.ina) 中国科学技术大学数学系安徽合肥

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关键词： Monotone coupling order statistics epidemic.

Negative Temperature coefficient of Resistivity in Bulk Nanostructured Ag

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Journal of Materials science & technology 2000年第5期16卷 521-524页

作者： Yushuang LIU, chimei MO+ and Weili cAI (department of Materials science and Engineering, university of science and technology of c.ina, hefei 230026, c.ina) department of Materials science and Engineering University of Science and Technology of China Hefei 230026 China

The change of the temperature coefficient of resistivity (a) with the particle size, dp, and the grain size, dc, in the nanostructured Ag bulk samples was investigated. dp and dc were controlled by heating the nano-Ag powders over the temperature range from 393 to 453 K. The electrical resistance measurements of the nanostructured Ag bulk samples obtained by compacting the Ag powders after heat treatments showed a change in the sign of a with dP and dc. When dp and dc are smaller or equal to 18 and 11 nm below room temperature or 20 and 12 nm above room temperature, respectively, the sign of the temperature coefficient of resistivity changes from positive to negative. The negative a arises mainly from the high resistivity induced by the particle interfaces with very lowly ordered or even disordered structure, a large volume fraction of interfaces and impurities existing in the interfaces, and the quantum size effect appearing in the nano-Ag grains.

关键词： Negative Temperature coefficient of Resistivity in Bulk Nanostructured Ag

Optimization of the inhibition of atmospheric window emission using photonic crystals

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science c.ina(Technological sciences) 2010年第5期53卷 1315-1319页

作者： LI Jin & YE Hong department of Thermal science and Energy and Engineering,university of science and technology of c.ina,hefei 230026,c.ina 1. department of Thermal science and Energy and Engineering University of Science and Technology of China Hefei 230026 China

Transfer matrix method is used to discuss the effect inhibition of photonic crystals on atmospheric window emission(ε-14 μm).According to the optical characteristics of the materials,germanium and zinc sulfide are used as the composing *** structure of the photonic crystals is optimized,and the optimal thickness values of the germanium and zinc sulfide are 0.63 and 1.11μm respectively while the ratio of optical thickness is 1:1 and the period is *** photonic crystals are prepared by evaporation coating method,and the optical properties of the photonic crystals are measured,the inhibition of the photonic crystals to atmospheric window emission is verified.

关键词： photonic crystals emission at atmospheric window inhibition