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Study on the two and three-parameter working stability regions of 3.-TZP suspension

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Science China(Technological Sciences) 2006年第5期49卷 547-568页

作者： CHEN Youqiang1, 2, ZHANG Xinni3. CHEN Sha’ou3.& QI Ping3.1. Department of chemistry, Qingdao university, Qingdao 266071, China 2. Department of chemistry, {3. university, beijing 100084, China 3. Department of Physics, Qingdao university, Qingdao 266071, China Department of chemistry Qingdao University Qingdao China Department of chemistry Tsinghua University Beijing China Department of Physics Qingdao University Qingdao China

We determined the variation tendency of viscosity (η) at various solids load- ing (α) for 3.-TZP suspension as a function of dispersant concentration (Cw) using vis- cosity measurement, measured the diameter of particles as a function of Cw in very dilute suspension using light scattering method, and obtained the surface features of the sedi- ment of suspension with different Cw using SEM. We also discussed the influence of the microstructure of adsorbed polymer layers on particles and their interactions in the dis- persing medium on the stability of suspension. Then two different stable states and two different unstable states for 3.-TZP suspension were given. Accordingly, the (Cw, η), (Cw, α), and (α, η) two-parameter, and (Cw, α, η) three-parameter stability maps were con- structed. Based on the DLVO theory calculations, the dispersant concentration, particle distance (r), and interparticle potential energy (VT) maps with various solids loading for 3.-TZP aqueous suspension were also constructed. In (Cw, r) two-parameter coordinate system, the stable motion region map for particles was established. The Cw, α, and VT,max (the highest potential energy) surface of the potential barrier map was obtained through calculation and simulation on the basis of the surfaces of Cw, r, VT maps introduced above. The (Cw, α) two-parameter stability map was then obtained from the Cw, α, VT,max map. The results showed that this theoretical map can qualitatively prove the experimentally obtained results—the existence of different dispersed states of particles in suspension system and the variation tendency of suspension stability with changing each parame- ter—were reasonable.

关键词： 3.-TZP, suspension, stability, DLVO theory, interparticle potential energy.

A MESSAGE-DRIVING FORMALISM FOR MODELING AND SIMULATION OF MULTI-AGENT SUPPLY CHAIN SYSTEMS

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Journal of Systems Science and Systems Engineering 2011年第4期20卷 385-399页

作者： Wenzhe TAN1 Yueting CHAI2 Yi LIU3.1Department of Automation, tsinghua university, beijing, {3., China 2Department of Automation, tsinghua university, beijing, {3., China 3.epartment of Automation, tsinghua university, beijing, {3., China Department of Automation Tsinghua University Beijing China

To acquire a competitive advantage in the expanding market, manufacturing enterprises should be able to manage their supply chains as effectively as possible. It is now becoming popular to model supply chains as multi-agent systems and use discrete event simulation to learn more about their behaviors or investigate the implications of alternative configurations. In order to enhance the computational efficiency and keep the simulation credibility, this paper proposes a message-driving formalism for the simulation of multi-agent supply chain systems. Through the message-driving formalism, the problem of shared variables is addressed and the parallel operation of agents is implemented. Simulation experiments with a prototype implementation show that the message-driving formalism is able to provide credible results in significantly less simulation time.

关键词： Supply chain multi-agent system modeling and simulation parallel discrete event simulation message-driving formalism

Luminescence of Eu^(2+) in Strontium Aluminum Oxide System with Long Decay Property

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Chinese Chemical Letters 1998年第4期9卷 401-402页

作者： Yong QIU and Hai Tao SUN(Department of chemistry, tsinghua university, {3. 100084) Department of chemistry Tsinghua University Beijing 100084 China

A long decay luminescent powder based upon the strontium aluminum oxide system with Eu2+ as the activator was produced. It was found that the variation of the molar ratio of Al to Sr leads to a change in emission colo... 详细信息

关键词： luminescence of Eu^(2+) strontium aluminum oxide emission

SIMULATION　CALCULATION　FOR　CHEMICAL　SPECIATION　OF　LEAD　BY　FEEDBACK　NEURAL　NETWORK

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Chinese Chemical Letters 1996年第3期7卷 265-266页

作者： Hua MO Bo DENG(Department of chemistry, tsinghua university, {3., 100084.) Department of chemistry Tsinghua University Beijing 100084

The chemical speciations of Ph2+ in the aqueous solution can becalculated using a Feedback Neural Network. The effects of CO3.2-), random errorand temperature on the simulation results were discussed. The results show... 详细信息

关键词： LEAD OF SPECIATION FEEDBACK CALCULATION BY

Coacervate Structures of CdI_2 Thin Film Grown during Phase Transformation

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Journal of Materials Science & Technology 1997年第4期13卷 296-298页

作者： Xiaoyan YE and Lili CAO(Dept. of chemistry, tsinghua university, {3. 100084, China)Jizhong ZHANG and Hengde LI(Dept. of Materials Scieuce & Engineering, tsinghua university, {3. 100084, China) Dept. of chemistry Tsinghua University Beijing 100084 China Dept. of Materials Science and Engineering Tsinghua University Beijing 100084 China

The microstructure of CdI2 thin film grown during vapor-phase deposition was investigated by scanning electron microscopy (SEM). The thin film deposited on Si crystal consists of numerous sunflower-like aggregates. These aggregates display well self-assembly characteristics. The size of Sunflower-like aggregates is between 12 and 44 μm. Each sunflower-like aggregate is surrounded with many adjacent wings-'petals'. The structure of central region of the 'sunflower' is obviously difFerent from that of the 'petal'. Electron spectroscopy for chemical analysis (ESCA) was employed in determining the chemical valence of the thin film. Self-organization efFect is used to explain the coring growth process of CdI2 thin film

关键词： Thin Coacervate Structures of CdI2 Thin Film Grown during Phase Transformation

Hexafluoro-2-propanol as a potent cosolvent for chemical ligation of membrane proteins

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Science China chemistry 2011年第1期54卷 110-116页

作者： SHEN Fei,TANG Shan & LIU Lei Department of chemistry,university of Science and Technology of China,Hefei 23.026,China Key Laboratory of Bioorganic Phosphorus chemistry and Chemical Biology,Ministry of Education Department of chemistry,tsinghua university.beijing 100084,China Department of chemistry University of Science and Technology of China Hefei China Key Laboratory of Bioorganic Phosphorus chemistry and Chemical Biology Ministry of Education Department of chemistry Tsinghua University Beijing China

The study on membrane proteins is an important challenge mainly because of their very poor solubility in various *** traditional recombinant expression strategy and the native chemical ligation method both have difficulty in generating sufficient amounts of desired proteins with high *** studies have shown that multiply fluorinated alcohols exhibit good ability to dissolve difficult peptide sequences,especially hexafluoro-2-propanol (HFIP).In the present study we systematically studied the capability of solvents containing different percentage of HFIP in dissolving transmembrane *** both HPLC and UV analyses we concluded that 60% HFIP/8 M urea constituted a good solvent *** this solvent system we also optimized conditions to perform native chemical ligation (NCL).Under the optimized conditions we successfully achieved NCL’s for both dipeptide formation and the synthesis of a model protein (Trifolitoxin).These results suggested that HFIP was a potential cosolvent that could be used in the ligation of poorly soluble peptides for the generation of membrane proteins.

关键词： membrane protein native chemical ligation alternative solvent hexafluoro-2-propanol

HIGH ACCURACY NUMERICAL METHOD OF THIN-FILM PROBLEMS IN MICROMAGNETICS

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Journal of Computational Mathematics 2003年第1期21卷 33-40页

作者： Zhongyi Huang (Deft, of Mathematical Sciences, tsinghua university, beijing, {3., China) Dept. of Mathematical Sciences Tsinghua University 北京 100084

In this paper, a new high accuracy numerical method for the thin-film problems of micron and submicron size ferromagnetic elements is proposed. For the computation of stray field, we use the finite element method(FEM) by introducing a semi-discrete artificial boundary condition [1, 2]. In our numerical experiments about the domain patterns and their movement, we can see that the results are accordant to that of experiments and other numerical methods. Our method are very convenient to deal with arbitrary shape of thin films such as a polygon with high accuracy.

关键词： Thin-film Micromagnetics stray field Semi-discrete artificial boundary condition.

SOME PROPERTIES OF LSQR FOR LARGE SPARSE LINEAR LEAST SQUARES PROBLEMS

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Journal of Systems Science & Complexity 2010年第4期23卷 815-821页

作者： Zhongxiao JIA Department of Mathematical Sciences,tsinghua university.beijing 100084,China. Department of Mathematical Sciences Tsinghua University Beijing China

It is well-known that many Krylov solvers for linear systems,eigenvalue problems,andsingular value decomposition problems have very simple and elegant formulas for residual *** not only allow us to further understand the methods theoretically but also can be usedas cheap stopping criteria without forming approximate solutions and residuals at each step beforeconvergence takes *** for large sparse linear least squares problems is based on the Lanczosbidiagonalization process and is a Krylov ***,there has not yet been an analogouslyelegant formula for residual *** paper derives such kind of *** addition,the authorgets some other properties of LSQR and its mathematically equivalent CGLS.

关键词： CGLS krylov subspace lanczos bidiagonalization least squares lsqr normal equations.

SYNTHESIS OF NOVEL SOLUBLE AROMATIC POLYPYROMELLITIMIDE CONTAINING ORDERED 1,2,4-TRIAZINE IN THE MAIN CHAIN

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Chinese Journal of Polymer Science 2002年第3期20卷 219-224页

作者： Xiao-bing Yi Guo-shi Wu Feng-cai Lu Department of chemistry tsinghua university, {3. 100084 China Institute of chemistry Chinese Academy of Sciences, {3. 100080, China Department of chemistry Tsinghua University 北京 100084 Institute of chemistry Chinese Academy of Sciences 北京 100080

A new heat-resistant, soluble polymer, poly(phenyl-1,2,4-triazine imide), has been prepared via a two-step method of polycondensation of N,N'-bis(4-benzil)pyromellitimide and terephthalamidrazone in cresol, followed by curing at higher temperature. The rigid 1,2,4-triazine group increases the solubility of the polyimide so that the polymer is soluble in cresol, N-methyl-2-pyrrolidone (NMP), trifluoroacetic acid and concentrated sulfuric acid, etc. Thermogravimetric analysis (TGA) indicates that this novel polyimide has good thermal stability with a high decomposition temperature of 447degreesC in air and of 423.degreesC in N-2, It has a tensile strength of 107.4 MI'a with an elongation at break of around 7.6%.

关键词： polyimides N,N '-bis(4-benzil)pyromellitimide rigid-rod group 1,2,4-triazine