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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 china,{3., china) 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 3.3.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 china(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 china,hefei 2.002.,china 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

Lie bialgebras of generalized Witt type

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science china Mathematics 2006年第4期49卷 533-544页

作者： SONG Guang’ai & SU Yucai College of Mathematics and Information science, Shandong Institute of Business and technology, Yantai 264005, china {3. of Mathematics, university of science and technology of china, hefei 2.002., china {3. of Mathematics, Shanghai Jiaotong university, Shanghai 200240, china College of Mathematics Information science Shandong Institute of Business technology Yantai 264005 China department of Mathematics University of Science technology of china Hefei 230026 China department of Mathematics Shanghai Jiaotong University Shanghai 200240 China

In this paper, all Lie bialgebra structures on the Lie algebras of generalized Witt type are considered. It is proved that, for any Lie algebra W of generalized Witt type, all Lie bialgebras on W are the coboundary triangular Lie bialgebras. As a by-product, it is also proved that the first cohomology group H1(W, W(?)W) is trivial.

关键词： Lie bialgebras, Yang-Baxter equation, Lie algebra of generalized Witt type.

CONTROLLED RADICAL COPOLYMERIZATION OF STYRENE AND MALEIC ANHYDRIDE UNDER GAMMA RADIATION IN THE PRESENCE OF BENZYL DITHIOBENZOATE

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Chinese Journal of Polymer science 2002年第6期20卷 525-530页

作者： De-cheng Wu Ying-fang Zou Cai-yuan Pan department of Polymer science and Engineering university of science and technology of china,{3., china Univ Sci & Technol china Dept Polymer Sci & Engn Hefei 230026 Peoples R China

The copolymerization of styrene (St) with maleic anhydride (MAh) under gamma radiation at room temperature in the presence of benzyl dithiobenzoate (BDTB) was found to display 'living' nature evidenced by constant concentration of chain radicals during the copolymerization, linear evolution of molecular weights with conversion and narrow molecular weight distribution (M-w/M-n = 1.23.1.3.). The compositional analysis and the sequence structural information of the copolymers obtained from DEPT (Distortionless Enhancement by Polarization Transfer) experiments demonstrate that the copolymers obtained also possess strictly alternating structure.

关键词： controlled radical polymerization alternating copolymer maleic anhydride styrene

Some new results about Jacobi forms

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Chinese science Bulletin 1997年第3期42卷 181-183页

作者： WANG Jupingdepartment of Mathematics, university of science and technology of china, hefei 2.002.,{3. department of Mathematics University of Science and Technology of China Hefei China

THE one-dimensional Jacobi forms were first systematically investigated by Eichler and Zagier, and a similar theory in a higher-dimensional case was developed by Ziegler, who gave the precise definition and some basic properties of higher-dimensional Jacobi forms. This note tries to give a satisfactory classification for a large kind of spaces of Jacobi forms. To be a little more explicit, we get a rank formula for Jacobi forms and then show that either all the

关键词： Jacobi forms rank coefficient estimation.

Effective temperature and exergy of monochromic blackbody radiation

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Progress in Natural science:Materials International 2007年第10期17卷 1250-1254页

作者： Chen Zeshao and Mo Songping(department of Thermal science and Energy Engineering, university of science and technology of china,{3., china) department of Thermal science and Energy Engineering University of Science and Technology of China Hefei 230027 China

A new parameter named monochromic effective temperature Tλ is proposed, which represents the thermodynamic quality of monochromic blackbody radiation. The exergy of the monochromic blackbody radiation is expressed by Tλ. The monochromic effective temperature equation is developed, which shows that the product of Tλ and the wavelength is constant, which equals 5.3.016×10-3.m·K. The exergy function of monochromic blackbody radiation is presented. The cause of the view that there is negative entropy production in photosynthesis can be explained by the results of this work.

关键词： photon monochromic effective temperature exergy of monochromic radiation.

DIRECT NUMERICAL SIMULATIONS OF TURBULENT CHANNEL FLOWS WITH CONSIDERATION OF THE BUOYANCY EFFECT OF THE BUBBLE PHASE

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Journal of Hydrodynamics 2011年第3期23卷 282-288页

作者： LIU Nan-sheng CHENG Bao-guo QUE Xia LU Xi-yun department of Modem Mechanics University of Science and Technology of China Hefei 230026 China department of Computer science and technology Hefei University of Technology Hefei 230009 China

Turbulent channel flows with consideration of the buoyancy effect of the bubble phase is investigated by means of the Direct Numerical Simulation （DNS）. This two-phase system is solved by a two-way coupling Lagrangian-Eulerian approach. The Reynolds number based on the friction velocity and the half-width of the channel is 194, and the gravitational acceleration varies from -0.5 to 0.5, ranging from the upflow to the downflow cases. This study aims to reveal the influence of buoyancy on the turbulence behavior and the bubble motion. Some typical statistical quantities, including the averaged velocities and velocity fluctuations for the fluid and bubble phases, as well as the flow structures of the turbulence fluctuations, are analyzed.

关键词： Direct Numerical Simulations (DNS) turbulent bubbly flow upflow/downflow turbulence fluctuations bubble statistics turbulence structures

Syntheses of amphiphilic biodegradable copolymers of poly(ethyl ethylene phosphate) and poly(3.hydroxybutyrate) for drug delivery

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science china Chemistry 2009年第7期52卷 961-968页

作者： CHENG Jing1 & WANG Jun2 1 department of Polymer science and Engineering, university of science and technology of china,{3., china 2 hefei National Laboratory for Physical sciences at Microscale, School of Life sciences, university of science and technology of china,{3., china department of Polymer science and Engineering University of Science and Technology of China Hefei 230026 China hefei National Laboratory for Physical sciences at Microscale School of Life Sciences University of Science and Technology of China Hefei 230027 China

Biodegradable and amphiphilic triblock copolymers poly(ethyl ethylene phosphate)-poly(3.hydroxybutyrate)-poly(ethyl ethylene phosphate) (PEEP-b-PHB-b-PEEP) have been successfully synthesized through ring-opening polymerization. The structures are confirmed by gel permeation chromatography and NMR analyses. Crystallization investigated by X-ray diffraction reveals that the block copolymer with higher content of poly(ethyl ethylene phosphate) (PEEP) is more amorphous, showing decreased crystallizability. The obtained copolymers self-assemble into biodegradable nanoparticles with a coreshell micellar structure in aqueous solution, verified by the probe-based fluorescence measurements and transmission electronic microscopy (TEM) observation. The hydrophobic poly(3.hydroxybutyrate) (PHB) block serves as the core of the micelles and the micelles are stabilized by the hydrophilic PEEP block. The size and size distribution are related to the compositions of the copolymers. Paclitaxel (PTX) has been encapsulated into the micelles as a model drug and a sustained drug release from the micelles is observed. MTT assay also demonstrates that the block copolymers are biocompatible, rendering these copolymers attractive for drug delivery.

关键词： poly(3.hydroxybutyrate) polyphosphoester drug delivery polymeric nanoparticles

Existence and Non-Existence of Periodic Solutions of Generalized Lineard Equations with Damping of No Lower Bound

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Acta Mathematica Sinica,English Series 1996年第4期12卷 361-371页

作者： Jiang Jifa department of Mathematics university of science and technology of china hefei, {3. china department of Mathematics University of Science and Technology of China Hefei China

This paper establishes criteria for the existence and non-existence of nonzero periodic solutions of the generalized Lienard equation （?）+f（x,（?））（?）+g（x）=*** main goal is to study to what extent the damping f can be small so as to guarantee the existence of nonzero periodic solutions of such a system. With some standard edditional assumptions we prove that if for a small |x|, ∫±∞|f（x,y）|-1dy=±∞, then the system has at least one nonzero periodic solution, otherwise, the system has no nonzero periodic solution. Many classical and well-known results can be proved as corollaries to ours.

关键词： Generalized Lienard equation Limit cycle