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Boundedness of solutions and existence of invariant tori for generalized pendulum type equation

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Chinese Science Bulletin 1997年第20期42卷 1673-1675页

作者： HUANG Hai and YUAN Rong1. Institute of Mathematics, Chinese Academy of Sciences, Beijing 100080, china 2. department of Mathematics, Beijing {2. university, Beijing 100875, china Institute of Mathematics Chinese Academy of Sciences Beijing China department of Mathematics Beijing Normal University Beijing China

MOTIVATED by various significant applications to non-Newtonian fluid theory, diffusion offlows in porous media, nonlinear elasticity, and theory of capillary surfaces, several authors(see refs.[1,2. and references cited therein ) have recently studied the existence of periodicsolutions and other properties for the following differential equation:

关键词： boundeduess of solutions invariant tori quasiperlodic solutions Moser’s small twist theorem.

Solvothermal synthesis of nanocrystalline FeS_2

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Science china(Physics,Mechanics & Astronomy) 2005年第2期48卷 188-200页

作者： CHEN Yanhua1, ZHENG Yufeng1, ZHANG Xiaogang2. SUN Yanfei1 & DONG Youzhong11. Physics department of Xinjiang university, Urumqi 830046,{2. 2. Institute of Applied chemistry of Xinjiang university, Urumqi 830046,{2. Physics department of Xinjiang university Urumqi 830046 China Institute of Applied chemistry of Xinjiang university Urumqi 830046 China

This paper reports on the synthesis of the nanocrystalline FeS2.via a solvent-thermal process. Using FeSO4 and NH2.SNH2.as precursors and polyvinyl- pyrrolidone (PVP) as a protective agent (dispersant), we have successfully synthesized nanocrystalline FeS2.both under acidic conditions (pH = 5) and under alkali conditions (pH = 10) at various temperatures and for different time in alcohol-water solution. X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Ultraviolet Visible (UV-VIS) spectroscopy were used to characterize the morphology, structure, particle size and optical characterization of sample synthesized under acidic condition, and the XRD pattern was refined by Rietveld method. The experimental result shows that nanocrystalline FeS2.with uniform size, highly crystallized quality and excellent dispersivity has been synthesized at 2.0℃for 36 h.

关键词： FeS2 (Pyrite), solvothermal, PVP, the Rietveld method.

Studies on the Electrochemistry of Dopamine at a Pyrocatechol Sulfonephthalein Modified Glassy Carbon Electrode

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Chemical Research in Chinese Universities 2000年第1期16卷 42-48页

作者： CAI Chen-xin and XUE Kuan-hong (department of chemistry, Nanjing {2. university, Nanjing 2.0097, P. R. china) Nanjing normal Univ Dept Chem Nanjing 210097 Peoples R China

The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported. The electrode can be used as a detector for the determination of dopamine with a high stability and a good sensitivity. The cyclic voltammetric results indicated that there was a couple of well-defined redox peaks for dopamine at the PS/GC electrode with E_(pa)= 2.0 mV, E_(pc)=95 mV and the formal potential E^(o')= 157. 5 mV(vs. SCE) at 100 mV/s in the buffer solution of pH 7. 0. The PS/GC electrode can also be used to separate the electrochemical responses of ascorbic acid and DA by 54 mV with the differential pulse voltammetry. Under the selected conditions, the oxidation peak currents are linear with DA concetration in the range of 5. 0 × 10^(-6) to 5. 0 × 10^(-4) mol/L, and the detection limit is 1. 0 ×10^(-6) mol/L at S/N=3. normalized with concentration, the relative sensitivity of dopamine to ascorbic acid reaches ca. 30. 8: 1.

关键词： Chemically modified electrode Neurotransmitter Dopamine Ascorbic acid Pyrocatechol sulfonephthalein

Smoothness for the collision local times of bifractional Brownian motions

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Science china Mathematics 2011年第9期54卷 1859-1873页

作者： SHEN GuangJun 1,2.& YAN LiTan 3 1 department of Mathematics,East china {2. of Science and Technology,Shanghai 2.02.7,china 2.department of Mathematics,Anhui normal {2.,Wuhu 2.1000,china 3 department of Mathematics,Donghua {2.,Shanghai 2.162.,china 1. department of Mathematics East China University of Science and Technology Shanghai 200237 China2. Department of Mathematics Anhui Normal University Wuhu 241000 China3. Department of Mathematics Donghua University Shanghai 201620 China

Let B^Hi,Ki ={ Bt^Hi,Ki, t ≥ 0}, i= 1, 2.be two independent bifractional Brownian motions with respective indices Hi ∈ （0, 1） and K∈ E （0, 1]. One of the main motivations of this paper is to investigate f0^Tδ（Bs^H1 ,K1 - the smoothness of the collision local time, introduced by Jiang and Wang in 2.09, IT = f0^T δ（Bs^H1,K1）ds, T 〉 0, where 6 denotes the Dirac delta function. By an elementary method, we show that iT is smooth in the sense of the Meyer-Watanabe if and only if min{H-1K1, H2.2. 〈-1/3.

关键词： bifractional Brownian motion collision local time intersection local time chaos expansion

Image interpretation of weak-coupling N-mer adsorbate's STM system

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Chinese Science Bulletin 1997年第5期42卷 371-374页

作者： HUANG Xintang, Ql Shouren, LI Xinjiao and LI Yongping1 department of Physics, Central china {2. university, Wuhan 430070, china department of Solid State Electronics, Huazhong university of Science and Technology, Wuhan 430074, china 2. department of Physics, university of Science and Technology of china, Hefei 2.002., china department of Physics Central China Normal University Wuhan China department of Solid State Electronics Huazhong University of Science and Techndogy Wuhan China department of Physics University of Science and Technology of China Hefei China

Up to now, there have been many indistinctive points in the image interpretation of scanning tunnelhng microscopy (STM) system, and the problems have attracted almost all STM scientists’ attention. In 1992. Kenkre proposed the new programme which describes the behaviour of the electrons moving in the STM tunnelling by the method of exciton dynamics, and the programme not only breaks through the restrictions of Tersoff-Hamann theory, but also can be applied conveniently to discussing the effects of the tip structure, adsorbate structure, substrate structure, temperature, tunneling voltage, and the degree of coherence of elec-

关键词： weak-coupling N-mer adsorbates STM image interpretation exciton dynamics method.

A local spin evaluation into the active site models of [2.e2.] ferrodoxin [Fe2.2.SR）4]2. （R=-H, -CH3）

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Science china chemistry 2007年第3期 327-334页

作者： WEI JiChong1,2. WANG Yan3 & JU GuanZhi2.3 1 department of chemistry,{2., Haikou 571158, china 2.State Key Laboratory of Theoretical and Computational chemistry, Jilin university, Changchun 13002., china 3 department of chemistry, Nanjing university, Nanjing 2.0093, china

To test the feasibility of local spin theory of Davidson and Clark for ferrodoxin clusters, the models [Fe2.2.SR）4]2. （R=-H, -CH3） are chosen for evaluation. This purpose is realized by calculating the local spin expectation valuesA·SB>,A2., and mA and discussing the connection between these expected values and the Heisenberg spin model （HSM） and the Noodleman broken-symmetry approach. In practical calculation, the spin-unrestricted Hartree-Fock （UHF） and spin-polarized density functional theory （DFT） are used and the calculational qualities of these two methods are also discussed. In addition, the theoretical magnetic coupling constants JAB of these models are calculated by various computational schemes for comparison with both theoretical and experimental results previously reported.

关键词： local spin iron-sulfur protein model density function theory magnetic coupling constant

Synthesis and Herbicidal Activities of N'-(substituted pyrimidin-2.yl)-N-Substituted Phenoxyacetyl Thiourea Derivatives

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Chinese Chemical Letters 2000年第1期11卷 19-20页

作者： Si Jia XUE Jin Shan ZOU Hai Jian YANG (department of chemistry, Central{2. normal university, Wuhan 430079) Cent china normal Univ Dept Chem Wuhan 430079 Peoples R China

Fifteen N'-(substituted pyrimidin-2.y1)-N-substituted phenoxyacetyl thioureas were synthesized and tested for biological activities. All of them are new compounds and their structures were confirmed by IR. IHNMR. MS and elemental analysis. Some of the target compounds showed excellent inhibitory activities against root and stalk of dicotyledon plant (such as radish). and selective on monoctyledon plant (such as rice).

关键词： 4-Nitrophenoxyacetyl thiourea 2.4-dichlorophenoxyacetyl thiourea synthesis 2.chlorophenoxyacetyl thiourea 2.amino pyrimidine herbicidal activity

γ-Radiation synthesis of nanocrystalline nickel powder from nickel (Ⅱ ) -ammonia complex solution

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Chinese Science Bulletin 1997年第8期42卷 644-648页

作者： ZHU Yingjie, QIAN Yitai and ZHANG Manwei1. department of Applied chemistry, {2. of Science and Technology of china, Hefei 2.002., china 2. Structure Research Laboratory, {2. of Science and Technology of china, Hefei 2.002., china Departnient of Applied chemistry University of Scirnce and Technology of China Hefei China Structure Research I.aboratory University of Science and Technology of China Hefei China

NANOCRYSTALLINE nickel is very important for its applications in the fields such as catalysis andmagnetic *** usual method used for preparing nanocrystalline nickel is inert gas e-vaporation,which requires high ***,high temperature easily leads tothe growth or oxidation of nickel *** et *** the nickel microaggre-gates dispersed in solution produced by γ-irradiating a dilute solution of Ni2.

关键词： nickel nanocrystalline powder γ-radiation.

Properties of meso-tetrakis (4-n-alkanoyloxyphenyl) porphyrin liquid crystal Co and Ni complexes

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Science china chemistry 2007年第4期50卷 488-493页

作者： LIU Wei1,2.& SHI TongShun2.1 College of Materials Science and Engineering, Shandong university of Technology, Zibo 2.5049, china 2.{2. of chemistry, Jilin university, Changchun 13002., china 1. College of Materials Science and Engineering Shandong University of Technology Zibo 255049 China 2. department of chemistry Jilin University Changchun 130023 China

Six series of meso-tetrakis (4-n-alkanoyloxyphenyl) porphyrin Co and Ni complexes (12.kinds) were reported. Nine of the compounds were found to exhibit liquid crystal properties and display a hexagonal columnar discotic columnar (Colh) phase. Molecular structure of all synthesized compounds was confirmed by IR, UV, MS, 1H NIVR, and elemental analysis. These liquid crystalline compounds have been studied by cyclic voltammetry, luminescence, and surface photovoltage spectroscopy.

关键词： porphyrin liquid crystal cyclic voltammetry luminescence surface photovoltage spectroscopy