Showing papers by "Nanjing University published in 2002"
TL;DR: In this article, in-situ LAM-MC-ICPMS microanalysis shows large variations in 176Hf/177Hf (up to 15 eHf units) between zircons of different growth stages within a single rock, and between zones within single zircon grains, suggesting that each of the observed magmas in both complexes developed through hybridisation of ≥2 magmas with different sources.
2,292 citations
TL;DR: The bias-variance decomposition of the error is provided in this paper, which shows that the success of GASEN may lie in that it can significantly reduce the bias as well as the variance.
1,898 citations
TL;DR: In this paper, as-prepared CuO nanoparticles with an average size of ca. 4nm have been successfully prepared by microwave irradiation, using copper (II) acetate and sodium hydroxide as the starting materials and ethanol as the solvent.
507 citations
TL;DR: In this paper, the physicochemical properties of nanoparticles were investigated by using size exclusion chromatography, FT-IR, dynamic light scattering, transmission electron microscope and zeta potential.
473 citations
472 citations
TL;DR: The pyridyltetrazolate ligand formed in situ from NaN3 and 3-cyanopyridine in the presence of ZnCl2 or CdCl2 in water affords acentric (1) or chiral (2) coordination polymers, respectively as mentioned in this paper.
Abstract: The pyridyltetrazolate ligand formed in situ from NaN3 and 3-cyanopyridine in the presence of ZnCl2 or CdCl2 in water affords acentric (1) or chiral (2) coordination polymers, respectively. The corresponding reaction of ZnCl2 with 4-cyanopyridine gives acentric 3 (not shown). Compounds 1-3 are second harmonic generation active.
470 citations
TL;DR: In this paper, the lowest energy structures and electronic properties of the clusters based on density-functional theory with local density approximation were investigated, and the most stable configurations obtained for the small clusters are amorphous instead of icosahedral or fcc-like.
Abstract: We have investigated the lowest-energy structures and electronic properties of the ${\mathrm{Au}}_{n}(n=2--20)$ clusters based on density-functional theory with local density approximation. The small ${\mathrm{Au}}_{n}$ clusters adopt planar structures up to $n=6.$ Flat cage structures are preferred in the range of $n=10--14$ and a structural transition from flat-cage-like structure to compact near-spherical structure is found around $n=15.$ The most stable configurations obtained for ${\mathrm{Au}}_{13}$ and ${\mathrm{Au}}_{19}$ clusters are amorphous instead of icosahedral or fcc like, while the electronic density of states sensitively depends on the cluster geometry. Dramatic odd-even alternative behaviors are obtained in the relative stability, highest occupied and lowest unoccupied molecular orbit gaps, and ionization potentials of gold clusters. The size evolution of the electronic properties is discussed and the theoretical ionization potentials of ${\mathrm{Au}}_{n}$ clusters compare well with experiments.
426 citations
TL;DR: The convergence of the proposed ADM method is proved under quite mild assumptions and flexible parameter conditions and the parameters to vary from iteration to iteration is proved.
Abstract: The alternating directions method (ADM) is an effective method for solving a class of variational inequalities (VI) when the proximal and penalty parameters in sub-VI problems are properly selected. In this paper, we propose a new ADM method which needs to solve two strongly monotone sub-VI problems in each iteration approximately and allows the parameters to vary from iteration to iteration. The convergence of the proposed ADM method is proved under quite mild assumptions and flexible parameter conditions.
417 citations
TL;DR: An L2 composing process model is proposed based on findings of a study on how ESL/EFL writers use their L1 when composing in their L2 (second language) and how such L1 use is affected by L2 proficiency and writing tasks.
370 citations
TL;DR: An automatic pathological diagnosis procedure named Neural Ensemble-based Detection (NED) is proposed, which utilizes an artificial neural network ensemble to identify lung cancer cells in the images of the specimens of needle biopsies obtained from the bodies of the subjects to be diagnosed.
355 citations
TL;DR: In this article, it is shown that as the flux rope rises, a piston-driven shock is formed along the envelope of the expanding CME, which sweeps the solar surface as it propagates.
Abstract: Solar coronal mass ejections (CMEs) are associated with many dynamical phenomena, among which EIT waves have always been a puzzle. In this Letter MHD processes of CME-induced wave phenomena are numerically simulated. It is shown that as the flux rope rises, a piston-driven shock is formed along the envelope of the expanding CME, which sweeps the solar surface as it propagates. We propose that the legs of the shock produce Moreton waves. Simultaneously, a slower moving wavelike structure, with an enhanced plasma region ahead, is discerned, which we propose corresponds to the observed EIT waves. The mechanism for EIT waves is therefore suggested, and their relation with Moreton waves and radio bursts is discussed.
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24 Jul 2002TL;DR: A model of delayed dynamic systems and the effects of a Short Time Delay on System Dynamics and Periodic Motions of Nonlinear Delay Systems are modeled.
Abstract: 1 Modeling of Delayed Dynamic Systems.- 2 Fundamentals of Delay Differential Equations.- 3 Stability Analysis of Linear Delay Systems.- 4 Robust Stability of Linear Delay Systems.- 5 Effects of a Short Time Delay on System Dynamics.- 6 Dimensional Reduction of Nonlinear Delay Systems.- 7 Periodic Motions of Nonlinear Delay Systems.- 8 Delayed Control of Dynamic Systems.- References.
TL;DR: It is shown here that the proposed neural network is stable in the sense of Lyapunov and globally convergent, globally asymptotically stable, and globally exponentially stable, respectively under different conditions.
Abstract: In this paper, we present a recurrent neural network for solving the nonlinear projection formulation. It is shown here that the proposed neural network is stable in the sense of Lyapunov and globally convergent, globally asymptotically stable, and globally exponentially stable, respectively under different conditions. Compared with the existing neural network for solving the projection formulation, the proposed neural network has a single-layer structure and is amenable to parallel implementation. Moreover, the proposed neural network has no Lipschitz condition, and, thus can be applied to solve a very broad class of constrained optimization problems that are special cases of the nonlinear projection formulation. Simulation shows that the proposed neural network is effective in solving these constrained optimization problems.
TL;DR: Results demonstrated that C. longa had specifically antidepressant effects in vivo, and may be mediated in part through MAO A inhibition in mouse brain.
TL;DR: A novel renewable reagentless hydrogen peroxide (H(2)O(2)) sensor based on the direct electron transfer of horseradish peroxidase (HRP) is proposed and displayed an excellent electrocatalytic response to the reduction of H(2), without the aid of an electron mediator.
TL;DR: It has been found that the combined irradiation of two or more frequencies of ultrasound can produce a significant increase in cavitation yield compared with single frequency irradiation, and the possible mechanisms of the enhanced effect are briefly discussed.
TL;DR: In this article, the effect of substitution of rare-earth La 3+ by hexagonal ferrites has been investigated by XRD, VSM and Mossbauer spectrum, and it has been shown that the substituted amount x at the maximum value of H cJ is bigger than that of σ s.
TL;DR: A water-compatible hypercrosslinked polymeric adsorbent (NJ-8) for adsorbing and removing phenolic compounds from their aqueous solutions was prepared and Freundlich isotherm equations indicate that the adsorption of Phenolic compounds on the NJ-8 resin is a physical adsorptive process.
TL;DR: In this article, a thermal decomposition of the precursor of ZnC2O4 obtained via chemical reaction between Zn(CH3COO)2·2H2O and H2C2OCO4·2HO2O in the presence of surfactant nonyl phenyl ether (9)/(5) and NaCl flux is discussed.
TL;DR: In this article, a model describing dynamics of bidirectional associative memory (BAM) neural networks with distributed delays is considered, and sufficient criteria of global asymptotic stability and uniform stability of an equilibrium point are given.
TL;DR: A new and facile vapor deposition method has been developed for the preparation of sol-gel matrix and to immobilize horseradish peroxidase (HRP) on a glassy carbon electrode surface for the production of an amperometric hydrogen peroxide biosensor.
Abstract: A new and facile vapor deposition method has been developed for the preparation of sol-gel matrix. This method was used to form a titania sol-gel thin film and to immobilize horseradish peroxidase (HRP) on a glassy carbon electrode surface for the production of an amperometric hydrogen peroxide biosensor. This process prevented the cracking of conventional sol-gel-derived glasses. The morphologies of both titania sol-gel and the enzyme membranes were characterized using scanning electron microscopy and proved to be chemically clean, porous, and homogeneous and to have a very narrow particle size distribution. The sol-gel-derived titania-modified electrode retained the enzyme bioactivity and provided for long-term stability of the enzyme in storage. In the presence of catechol as a mediator, the sensor exhibited a rapid electrocatalytic response (less than 5 s), a linear calibration range from 0.08 to 0.56 mM with a detection limit of 1.5 microM and a high sensitivity (61.5 microA mM(-1)) for monitoring of H2O2. Effects of pH and operating potential were also explored for optimum analytical performance by using the amperometric method. The apparent Michaelis-Menten constant of the encapsulated HRP was 1.89 +/- 0.21 mM.
TL;DR: The solid-state structure and nature of 1 provide an indication of the type of materials that may be formed as intermediates in the Sharpless-Demko reaction for the generation of 5-substituted 1H-tetrazoles.
Abstract: The reaction of 4-cyanopyridine with NaN(3) in the presence of H(2)O and a Lewis acid (CdCl(2)) affords a novel 3D pillared-layered fluorescent and phosphorescent coordination polymer Cd(3)(OH)(2)Cl(2)(4-PTZ)(2) (4-PTZ = 5-(4-pyridyl)tetrazolate) (1) while the direct reaction of CdCl(2) with H-PTZ gives the simpler species Cd(4-PTZ)(2)(H(2)O)(2). The solid-state structure and nature of 1 provide an indication of the type of materials that may be formed as intermediates in the Sharpless-Demko reaction for the generation of 5-substituted 1H-tetrazoles.
TL;DR: Bismuth sulfide nanorods have been successfully prepared by a sonochemical method from an aqueous solution of bismuth nitrate and sodium thiosulfate in the presence of complexing agents as mentioned in this paper.
Abstract: Bismuth sulfide nanorods have been successfully prepared by a sonochemical method from an aqueous solution of bismuth nitrate and sodium thiosulfate in the presence of complexing agents. Bismuth su...
TL;DR: In this article, the relationship of projection-type methods for monotone nonlinear variational inequalities was investigated and improvements were made. But the work in this paper is restricted to the case where the proximal point method is the corresponding implicit method.
Abstract: In this paper, we study the relationship of some projection-type methods for monotone nonlinear variational inequalities and investigate some improvements. If we refer to the Goldstein-Levitin-Polyak projection method as the explicit method, then the proximal point method is the corresponding implicit method. Consequently, the Korpelevich extragradient method can be viewed as a prediction-correction method, which uses the explicit method in the prediction step and the implicit method in the correction step. Based on the analysis in this paper, we propose a modified prediction-correction method by using better prediction and correction stepsizes. Preliminary numerical experiments indicate that the improvements are significant.
TL;DR: In this paper, an extension of the eigenface technique, i.e. projection-combined principal component analysis, (PC)2A, is proposed and it requires less computational cost and achieves 3-5% higher accuracy on a gray-level frontal view face database where each person has only one training image.
TL;DR: In this article, the chain length dependence of excitation energies of polyene, polyphenylene, pentafulvene, cyclopentadiene, pyrrole, furan, silole, phosphole, and thiophene was studied employing the time-dependent density functional theory with B3LYP functional.
Abstract: The chain length dependence of excitation energies of oilgomers of polyene, p-phenylene, pentafulvene, cyclopentadiene, pyrrole, furan, silole, phosphole, and thiophene was studied employing the time-dependent density functional theory with B3LYP functional. Band gaps and effective conjugation lengths of the corresponding polymers were obtained by extrapolating vertical excitation energies of trimers through pentamers to infinite chain length. Polypentafulvene, polycyclopentadiene, polysilole, and polyphosphole were predicted to have smaller band gaps than polythiophene, and polypentafulvene has the smallest band gap. Among the studied cyclopentadiene-based polymers, those with the third row heteroatoms were found to have narrower band gaps than their second row counterparts.
TL;DR: The PEO/PCL ratio of copolymer was a main factor in controlling micelle size, drug‐loading content, and drug release behavior as PCL weight ratio increased, themicelle size and drug‐ loading content increased, and the drug release rate decreased.
TL;DR: In this paper, single-crystal cubic NiO nanorods with diameters of 30-80 nm and lengths of up to tens of micrometers were synthesized by using a simple precursor thermal decomposition in NaCl flux with NiCO3 as the precursor, which was prepared by one-step, solidstate reaction of NiCl2·6H2O and Na2CO3 at ambient temperature.
TL;DR: The results of thermal analysis (DSC) further confirm that the phase transition for 1 and 2 is first-order but maybe second-order for 3, and the phenomena observed in this study are similar to those of the 1-D radical systems.
Abstract: Three ion-pair complexes, [RbzPy]+[Ni(mnt)2]- (mnt2- = maleonitriledithiolate; [RbzPy]+ = 4-R-benzylpyridinium; R = Br (1), Cl (2), and NO2 (3)), with unusual magnetic properties have been synthesized and characterized. The crystal structures of 1 and 2 have been solved. The two complexes belong to the P21/c space group with Z = 4 and C20H11BrN5NiS4, a = 12.0744(17) A, b = 26.369(4) A, c = 7.440(3) A, and β = 102.63(3)° for 1 and C20H11ClN5NiS4, a = 12.105(2) A, b = 26.218(4) A, c = 7.374(2) A, and β = 102.55(2)° for 2, respectively. The [Ni(mnt)2]- anions in 1−3 form uniformly spaced one-dimensional (1-D) magnetic chains of s = 1/2 at room temperature. The temperature dependences of the susceptibility for 1−3 show that they undergo phase transitions. All three complexes are paramagnetic in their high-temperature (abbreviation HT) phase and diamagnetic in the low-temperature (abbreviation LT) phase because of strong dimerization along the stacking direction. The results of thermal analysis (DSC) further c...