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

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 {2., Qingdao 2.6071, china 2. department of chemistry, tsinghua university, beijing 100084, china 3. department of Physics, Qingdao {2., Qingdao 2.6071, 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 3Y-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 3Y-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 3Y-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： 3Y-TZP, suspension, stability, DLVO theory, interparticle potential energy.

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Surface effects of monolayer-protected gold nanoparticles on the redox reactions between ferricyanide and thiosulfate

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Science china chemistry 2005年第5期48卷 424-430页

作者： LI Di1, SUN Chunyan1, HUANG Yunjie1, LI Jinghong1,2.& CHEN Shaowei3 1. State Key Laboratory of Electroanalytical chemistry, Changchun Institute of Applied chemistry, Chinese Academy of Sciences, Changchun 13002.,{2. 2. department of chemistry, tsinghua university, beijing 100084,{2. 3. department of chemistry, university of California, Santa Cruz, Santa Cruz, CA 95064, USA State Key Laboratory of Electroanalytical chemistry Changchun Institute of Applied chemistry Chinese Academy of Sciences Changchun China department of chemistry Tsinghua University Beijing China department of chemistry University of California Santa Cruz Santa Cruz USA

Electron transfer through the self-assembled monolayers (SAMs) on gold nanopar-ticles is investigated by using the monolayer protected gold nanoclusters (MPCs) as elec-tron-transfer mediators. 3-Mercaptopropionic acid (MPA) and 11-meraptoundecanoic acid (MUA) MPCs were employed to catalyze the redox reaction between potassium ferricyanide and sodium thiosulfate. The catalytic mechanism was proposed that the MPCs act as diffusing elec-tron-mediators and electron transfers to and from the MPCs surface. Therefore the electron transfer rate through the capping layers would be proportional to the MPCs catalyzed reaction rate, which was monitored by the UV absorbance of ferricyanide. The calculated apparent rate constant was orders of magnitude smaller than that of the maximum of tunneling current, which was attributed to the splited energy level of the nanoscale particles.

关键词： electron transfer, three-dimensional self-assembled monolayers, redox reaction, electron transfer mediator, surface effect.

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二正丁基锡双(二茂铁硫代甲酸酯)配合物的红外光谱和核磁共振谱

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分析测试学报 2002年第2期21卷 70-72页

作者：卢文贯陶家洵韶关大学化学系广东韶关512005 清华大学化学系北京100084

合成了二正丁基锡新型配合物(n_Bu)2.n(FcCOS)2.Fc= (η_C5H5)Fe(1_5_η_C5H4)—] ;研究了该配合物的红外光谱和核磁共振(1H、13C、119Sn)谱。

关键词：红外光谱核磁共振谱分子结构抗癌药物二正丁基锡双(二苯铁硫代甲酸酯)配合物

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催化剂Ni/Y_2._3上低温乙醇水蒸气重整制氢研究——氢气预还原对催化剂性能的影响

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燃料化学学报 2004年第5期32卷 590-595页

作者：孙杰邱新平吴锋王国庆陈实北京理工大学化工与环境学院北京100081 清华大学化学系

用浸渍-热分解-氢还原法(IHDHR)和浸渍-热分解法(IHD)分别制备了两种纳米尺寸的Ni Y2.3催化剂,并应用X 光电子能谱、X 射线衍射、BET比表面测试等分析技术对两种催化剂的结构进行了表征和比较。采用固定床反应器对两种催化剂的催化性能... 详细信息

用浸渍-热分解-氢还原法(IHDHR)和浸渍-热分解法(IHD)分别制备了两种纳米尺寸的Ni Y2.3催化剂,并应用X 光电子能谱、X 射线衍射、BET比表面测试等分析技术对两种催化剂的结构进行了表征和比较。采用固定床反应器对两种催化剂的催化性能进行实验测试。结果表明,氢气预还原与否对该纳米Ni Y2.3催化剂的催化性能有一定的影响,经过氢气预还原的催化剂对低温乙醇水蒸气重整反应表现出较高的活性和稳定性,2.0℃时,乙醇的转化率达到81.9%;32.℃时,乙醇的转化率达到95.3%,对氢气的选择性为53.6%。对经过氢预还原的Ni Y2.3催化剂进行了60h的稳定性测试。

关键词：三氧化二钇负载镍催化剂乙醇水蒸气重整氢气预还原催化性能氢能清洁能源

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Observation on Etch Pits of Single Crystal Copper

Observation on Etch Pits of Single Crystal Copper

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第15届全国晶体生长与材料学术会议

作者： Youxin. Lou 1, Wenxun. Yan 2.,Qqiang. Li 2.,Jiyang. Wang 1 1.State key lab of crystal material, Shandong university,Jinan 2.0100, china {2. .tsinghua university, beijing100084,china

Copper single crystals are grown by czochraski method under the protection of gas Ar at more or less 1 atm. The single crystal direction is determined by X-Ray Diffraction. The characters of morphological Pyramids have been examined by Metallurgical Microscope and Scanning Electron Microscope technology. It is discovered that some irregular morphology appearing on the surface is related with some regulars. Finally the dislocation density is calculated up to 107/cm2..

关键词： chemical etching dislocation density copper czochraski method

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一种活性高、热稳定性好的甲醇合成催化剂

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天然气化工—C1化学与化工 2004年第2期29卷 16-19页

作者：王兆谦潘伟雄李晋鲁青海大学应用化学系西宁810016 清华大学化学系北京100084

甲醇合成催化剂中添加第4组分Zr,制得Cu Zn Al Zr催化剂,研究了制备方法对4组分甲醇合成催化剂性能的影响。用改进沉淀法所得催化剂活性最高,在2.0℃,3 0MPa,5500ml/(g cat·h)空速的温和条件下,甲醇时空产率达到0 978g/(g cat·h),活... 详细信息

甲醇合成催化剂中添加第4组分Zr,制得Cu Zn Al Zr催化剂,研究了制备方法对4组分甲醇合成催化剂性能的影响。用改进沉淀法所得催化剂活性最高,在2.0℃,3 0MPa,5500ml/(g cat·h)空速的温和条件下,甲醇时空产率达到0 978g/(g cat·h),活性和热稳定性均优于两种工业化催化剂C301和APCI。尤其是在2.0℃的较低温度下,活性是它们的两倍。XRD结果表明催化活性与前驱体结构密切相关。

关键词：甲醇合成铜基催化剂 XRD

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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, {2., 100084, china 2.0} of Automation, tsinghua university, {2., 100084, china 3department of Automation, tsinghua university, {2., 100084, 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

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Closed and endoreversible chemical oscillation

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Chinese Journal of chemistry 1994年第3期12卷 199-205页

作者： LI, Ru-Shengdepartment of chemistry,{2., beijing 100084, china department of chemistry Tsinghua University Beijing 100084 China

Based on a simple nonideal chemical reaction model, the closed system with reversible nonideal reactions and illumination is shown to be able to exhibit sustained oscillation. The essential points in the occurrence of such oscillations are the nonideality of reacting media, which gives rise to multiple chemical equilibria, and the energy flow through illumination and heat conduction, which gives rise to spontaneous transitions repeatedly between the multiple equilibrium states. During the oscillation, reacting media undergo only reversible chemical transformation and all irreversibilities are restricted to the coupling of the system to external world. This oscillation provides an example of the so-called endoreversible machine and a possible way to convert radiation energy of the light directly into mechanical energy.

关键词： Chemical oscillation closed system nonideality endoreversible machine illumination.

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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 {2.,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.

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THE EXISTENCE OF J-HOLOMORPHIC CURVES AND APPLICATIONS TO THE WEINSTEIN CONJECTURE

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Chinese Annals of Mathematics,Series B 1999年第4期20卷 425-434页

作者： MA RENYI(department of Applied Mathmatics, tsinghua university,{2., china) department of Applied Mathmatics Tsinghua University Beijing 100084 China

The author first proves the existences of J-holomorphic curves in the symplectizations of Legendre fibrations and then as an application confirms the Weinstein conjectures on contact manifolds of Legendre fibrations. As a corollary a new proof on the theorem due to Hofer,Viterbo, Gluck, Ziller, Weinstein and Ljusternik-Fet Theorem is provided, which is quite different from their original proofs.

关键词： Symplectic geometry J-holomorphic curves Periodic orbit

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