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Nonlinear boundary value problems for discontinuous delayed differential equations

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Applied Mathematics(A Journal of Chinese Universities) 2010年第1期25卷 9-17页

作者： SUN Wu-jun department of Finance & Insurance, Business School of nanjing university, nanjing 210093, china department of Finance and Insurance Business School of Nanjing University Nanjing China

In this paper nonlinear boundary value problems for discontinuous delayed differen- tial equations are considered. Some existence and boundedness results of solutions are obtained via the method of upper and lower solutions, which may be discontinuous. Our analysis can be applied to those phenomena from physics and control theory which have been successfully described by delayed differential equations with discontinuous functions, such as electric, pneu- matic, and hydraulic networks. It is also an important step to precede the design of control signals when finite-time or practical stability control are concerned.

关键词： Nonlinear boundary value problems upper and lower solutions discontinuous delayed differentialequations Carath^odory conditions existence of solutions.

Anion Adsorption on an Au Colloid Monolayer Based Cysteamine-Modified Gold Electrode

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Chemical Research in Chinese Universities 2001年第2期17卷 159-167页

作者： HU Xiao-ya, XIAO Yi and CHEN Hong-yuan (department of chemistry, The State Key Laboratory of Coordination chemistry, nanjing university, nanjing 210093, P. R. china) nanjing Univ Dept Chem State Key Lab Coordinat Chem Nanjing 210093 Peoples R China

Anion adsorption behavior on Au colloid surface was investigated in virture of depositing monolayers of Au colloid on the self-assembled monolayers of cysteamine on a gold electrode. Po- tential-dependent anion adsorption-desorption waves via the nonfaradaic current were obtained by means of cyclic voltammetry at Au coltoid-modified gold electrodes in the potential range of -2 00-600 mV. The adsorption sequence in the order of adsorption peak potentials (Epa) is OH- >citrate3 ->H2PO4- >Cl->SO42->ClO4->NO3-. Among them, citrate3- exhibited an en- tirely irreversible adsorption. A rise in temperature can increase the rates of adsorption-desorp- tion and improve the reversibility of the adsorption-desorption of Cl-, SO42-, ClO4-, NO3- and H2PO-4. The adsorption peak potentials shifted more negatively for Ca. 63 mV as the anion con- centrations were increased by a decade factor. The change of pH from 7 to 1 slightly affected the adsorption peak potentials of Cl- and NO3-. Au colloids with a smaller size (16 nm) gave rise to a better reversibility of the adsorption-desorption process and lower adsorption currents. The ex- perimental results of citrate ions adsorption on Au colloid surface show that Au colloids with a smaller size prepared by sodium citrate method exhibited a higher stability in the solution in com- parison to those with larger sizes because of its higher ratio of charge/mass. In other words, the smaller gold nanoparticles are covered with citrate ions monolayer that can also be formed at larg- er gold nanoparticles by means of electrochemical scan.

关键词： Colloidal gold Self-assembled monolayer Gold electrode Electrode dynamics

Quantitativ　estructure－activity　relationships　for　studying　alkyl（1－phenylsulfonyl）　cycloalkane－carboxylates

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Journal of Environmental Sciences 1996年第2期8卷 157-166页

作者： He Yibing Wang Liansheng (department of Environmental Science and Engineering, nanjing university, nanjing 210093, china) department of Environmental Science Nanjing University Nanjing 210093 China

Octanol/water partition coefficients,adsorption coefficients for soils and sediments and acute toxicities to Daphnia magna of 28 alkyl (1-phenylsulfonyl) cycloalkane-carboxylates were measured. These properties were correlated by linear solvation energy relationship (LSER) and chromatographic retention data determined by reverse-phase high performance liquid chromatography (RP-HPLC). The accuracy and range of applicability of these two quantitative structure-activity relationship (QSAR) methods were compared in this paper.

关键词： alkyl (1-phenylsulfonyl) cycloalkane-carboxylates LSER R-PHPLC.

Representation dimension for Hopf actions

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Science china Mathematics 2012年第4期55卷 695-700页

作者： SUN JuXiang & LIU GongXiang department of Mathematics,nanjing university,nanjing 210093,china 1. department of Mathematics Nanjing University Nanjing 210093 China

Let H be a finite-dimensional Hopf algebra and assume that both H and H＊ are semisimple. The main result of this paper is to show that the representation dimension is an invariant under cleft extensions of H, that is... 详细信息

关键词： representation dimension finite representation type crossed product

Effect of Conversion Efficiency on Gamma-Ray Burst Energy

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Chinese Journal of Astronomy and Astrophysics 2004年第3期4卷 267-274页

作者： Lei Xu Zi-Gao Dai department of Astronomy nanjing university nanjing 210093 department of Astronomy Nanjing University Nanjing 210093

Beaming effect makes it possible that gamma-ray bursts have a standardenergy, but the gamma-ray energy release is sensitive to some parameters. Our attention is focusedon the effect of the gamma ray conversion efficiency (η_γ), which may range between 0.01 and 0.9,and which probably has a random value for different GRBs under certain conditions. Making use of theafterglow data from the literature, we carried out a complete correction to the conical openingangle formula. Within the framework of the conical jet model, we ran a simple Monte Carlo simulationfor random values of η_γ, and found that the gamma-ray energy release is narrowly clustered,whether we use a constant value of η_γ or random values for different gamma-ray bursts.

关键词： gamma rays: bursts ISM: jets

Rank of K_2 of elliptic curves

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Science china Mathematics 2009年第10期52卷 2107-2120页

作者： JI QingZhong & QIN HouRong department of Mathematics, nanjing university, nanjing 210093, china 1. department of Mathematics Nanjing University Nanjing 210093 China

We prove that (i) rank(K2(E)) 1 for all elliptic curves E defined over Q with a rational torsion point of exact order N 4; (ii) rank(K2(E)) 1 for all but at most one R-isomorphism class of elliptic curves E defined ov... 详细信息

关键词： elliptic curve regulator map Né ron model

IMPEDANCE CHARACTERISTICS OF POLYFURAN FILMS

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Chinese Journal of Polymer Science 2002年第5期20卷 419-423页

作者： Liang Li Xiao-bo Wan Gi Xue department of Polymer the State Key Laboratory of Coordination chemistry nanjing university nanjing 210093. china nanjing Univ Dept Polymer State Key Lab Coordinat Chem Nanjing 210093 Peoples R China

Electrochemical impedance spectroscopy (EIS) was first used for the characterization of polyfuran (PFu) films that had been formed electrochemically on an Au electrode. The polyfuran was measured in high oxidation state, intermediate oxidation state and reduction state, respectively. As the oxidation level is increased, the ionic conductivity of PFu/BF4- increases. And impedance studies on PFu show that the anion BF4- appears to be mobile with a high diffusion coefficient of approximately 10(-8) cm(2).s(-1).

关键词： polyfuran electrochemical impedance spectroscopy capacitance

Precession of the Orbital Plane of Binary Pulsars and Significant Variabilities

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Chinese Journal of Astronomy and Astrophysics 2005年第4期5卷 379-398页

作者： Bi-Ping Gong department of Astronomy, nanjing university, nanjing 210093 bpgong@*** department of Astronomy Nanjing University Nanjing 210093

There are two ways of expressing the precession of orbital plane of a binary pulsar system, given by Barker ＆ O＇Connell, Apostolatos et al. and Kidder, respectively. We point out that these two ways actually come from the same Lagrangian under different degrees of freedom. Damour ＆ Schaefer and Wex Kopeikin applied Barker ＆ O＇Connell＇s orbital precession velocity in pulsar timing measurement. This paper applies Apostolatos et al.＇s and Kidder＇s orbital precession velocity. We show that Damour ＆ Schaefer＇s treatment corresponds to negligible Spin-Orbit induced precession of periastron, while Wex ＆ Kopeikin and this paper both found significant （but not equivalent） effects. The observational data of two typical binary pulsars, PSR J2051-0827 and PSR J1713＋0747, apparently support a significant Spin-Orbit coupling effect. Specific binary pulsars with orbital plane nearly edge on could discriminate between Wex ＆ Kopeikin and this paper： if the orbital period derivative of the double-pulsar system PSRs J0737-3039 A and B, with orbital inclination angle i=87.7-29^＋17 deg, is much larger than that of the gravitational radiation induced one, then the expression in this paper is supported, otherwise Wex ＆= Kopeikin＇s is supported.

关键词： pulsars: binary pulsars - geodetic precession: individual (PSR J2051-0827 PSR J1713+0747 PSRs J0737-3039 A and B)

PREPARATION　OF　SPHERICAL，　MONODISPERSED　NANOMETER　Eu_2O_3　PARTICLES

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Chinese Chemical Letters 1995年第10期6卷 915-918页

作者： Jun MA Qi Jie YAN(department of chemistry, nanjing university, nanjing 210093) nanjing Univ Dept Chem Nanjing 210093 Peoples R China

Spherical, monodispersed europium hydroxycarbonate particles wereobtained by homogeneous precipitation with urea in aqueous solution of Eu.(NO3)3at elevated *** particles were readily converted to the uniformEu2O3 wit... 详细信息

关键词： Eu2O3 MONODISPERSED NANOMETER OF PARTICLES