Showing papers by "Nanjing University of Science and Technology published in 2008"
TL;DR: In this article, a general approach for the preparation of graphene−metal particle nanocomposites in a water−ethylene glycol system using graphene oxide as a precursor and metal nanoparticles (Au, Pt and Pd) as building blocks.
Abstract: Graphene sheets, which possess unique nanostructure and a variety of fascinating properties, can be considered as promising nanoscale building blocks of new composites, for example, a support material for the dispersion of nanoparticles. Here, we present a general approach for the preparation of graphene−metal particle nanocomposites in a water−ethylene glycol system using graphene oxide as a precursor and metal nanoparticles (Au, Pt and Pd) as building blocks. These metal nanoparticles are adsorbed on graphene oxide sheets and play a pivotal role in catalytic reduction of graphene oxide with ethylene glycol, leading to the formation of graphene−metal particle nanocomposites. The typical methanol oxidation of graphene−Pt composites in cyclic voltammograms analyses indicated its potential application in direct methanol fuel cells, bringing graphene−particle nanocomposites close to real technological applications.
1,478 citations
TL;DR: The purpose of this article is to survey the recent results developed to analyse the asymptotic stability of time-delay systems and give special emphases to the issues of conservatism of the results and computational complexity.
Abstract: Recent years have witnessed a resurgence of research interests in analysing the stability of time-delay systems. Many results have been reported using a variety of approaches and techniques. However, much of the focus has been laid on the use of the Lyapunov-Krasovskii theory to derive sufficient stability conditions in the form of linear matrix inequalities. The purpose of this article is to survey the recent results developed to analyse the asymptotic stability of time-delay systems. Both delay-independent and delay-dependent results are reported in the article. Special emphases are given to the issues of conservatism of the results and computational complexity. Connections of certain delay-dependent stability results are also discussed.
385 citations
TL;DR: In this paper, a composite of graphite oxide (GO)-supported Co3O4nanoparticles (NPs) was prepared through a facile chemical route, and the lamellar GO sheets in this composite were exfoliated and decorated randomly by Co 3O4 particles with an average size of 100 nm.
Abstract: A composite of graphite oxide (GO)-supported Co3O4nanoparticles (NPs) was prepared through a facile chemical route. The lamellar GO sheets in this composite were exfoliated and decorated randomly by Co3O4 particles with an average size of 100 nm. The formation route to anchor Co3O4 NPs onto the exfoliated GO sheets was proposed as the intercalation and adsorption of cobalt ions into the layered GO sheets, followed by the nucleation and growth of Co3O4 crystals, resulting in the exfoliation of GO sheets. The nanocomposite reveals unusual catalytic effect for the decomposition of ammonium perchlorate due to the concerted effects of GO and Co3O4 NPs or their integrated properties. This methodology made the synthesis of GO-NP composites possible and may be further extended to prepare more complicated nanocomposites based on GO sheets for technological applications.
300 citations
TL;DR: Superfine powders of poly (methyl methacrylate) (PMMA) have been prepared by means of an emulsion polymerization method and have been used as templates in the synthesis of tetragonal phase mesoporous zirconia by the sol–gel method, usingZirconium oxychloride and oxalic acid as raw materials.
Abstract: Superfine powders of poly (methyl methacrylate) (PMMA) have been prepared by means of an emulsion polymerization method. These have been used as templates in the synthesis of tetragonal phase mesoporous zirconia by the sol–gel method, using zirconium oxychloride and oxalic acid as raw materials. The products have been characterized by infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, N2adsorption-desorption isotherms, and pore size distribution. The results indicate that the average pore size was found to be 3.7 nm.
240 citations
TL;DR: The interrelationship between the two one-dimensional ESPRIT is utilised to obtain automatically paired transmit angles and receive angle estimation without debasing the performance of angle estimation in a bistatic MIMO radar.
Abstract: Recently, it has been shown [Duofang et al.] how the ESPRIT algorithm exploited the invariance property of both the transmit array and the receive array for target direction estimation in a bistatic MIMO radar. However, this method estimates the transmit angles and the receive angles separately in each dimension, and then requires pair matching between the two-dimensional angle estimation, which requires additional computational load. In this reported work, the interrelationship between the two one-dimensional ESPRIT is utilised to obtain automatically paired transmit angles and receive angle estimation without debasing the performance of angle estimation in a bistatic MIMO radar. Simulation results are presented to verify the effectiveness of the proposed method.
232 citations
197 citations
TL;DR: The reduced conservatism of the proposed stability result is shown through a numerical example, while the applicability of the time-delayed controller design method is demonstrated by an inverted pendulum system.
186 citations
TL;DR: Synthesis of SiC nanoparticles with diameters of tens of nanometers shows emission in the blue-to-UV range and the observed emissions can be ascribed to some surface or defect states in the SiC nanostructures.
Abstract: Quantum dots are superior to dye molecules in many aspects from size-tunable fluorescence and resistance to photobleaching and they have thus been widely used in biology as fluorescent probes. However, the cytotoxicity of some quantum dots limits their use in biological systems, and exploiting green nanoparticles with low cytotoxicity has become one major concern in this field. Silicon carbide, one well-known power electronic semiconductor material, is considered one of the best biocompatible materials, especially to blood. In addition, it has superior properties such as low density, high hardness, high strength, and chemical inertness. In recent years, much effort has been made to synthesize nanocrystalline SiC and study its photoluminescence (PL) properties. Some synthesized SiC nanostructures showed emission in the blue-to-UV range with their properties depending sensitively on the fabrication method and even on specific experiments. Although some variations have been reported, in general the observed emissions can be ascribed to some surface or defect states in the SiC nanostructures. However, owing to their relatively large size, low emission intensity, lack of controlled synthesis, and variable optical properties, these interconnected SiC nanostructures can hardly be used as fluorescent biological labels. Kassiba and co-workers synthesized SiC nanoparticles with diameters of tens of nanometers
175 citations
TL;DR: This paper attempts to present research focusing on a complex incomplete information system-the incomplete ordered information system, where all attributes are considered as criterions and classification analysis in such incomplete information systems is conducted.
175 citations
TL;DR: Zhang et al. as mentioned in this paper put forward a new method of co-occurrence matrix to describe image features, which can express the spatial correlation of textons, and quantized the original images into 256 colors and computed color gradient from the RGB vector space.
163 citations
TL;DR: In this article, 2D hierarchical cellular materials made up of sandwich walls are predicted to have superior mechanical properties compared with solid-wall cellular materials, including stiffness, buckling strength, plastic collapse strength, brittle failure strength and fracture toughness.
TL;DR: In this paper, the design and measured results of a 2 times 2 microstrip line-fed U-slot rectangular antenna array are presented, where the U slot patches and the feeding network are placed on the same layer, resulting in a very simple structure.
Abstract: The design and measured results of a 2 times 2 microstrip line fed U-slot rectangular antenna array are presented. The U-slot patches and the feeding network are placed on the same layer, resulting in a very simple structure. The advantage of the microstrip line fed U-slot patch is that it is easy to form the array. An impedance bandwidth (VSWR < 2) of 18% ranging from 5.65 GHz to 6.78 GHz is achieved. The radiation performance including radiation pattern, cross polarization, and gain is also satisfactory within this bandwidth. The measured peak gain of the array is 11.5 dBi. The agreement between simulated results and the measurement ones is good. The 2 times 2 array may be used as a module to form larger array.
TL;DR: In this paper, the effects of counterface materials on the tribological behavior of composites were investigated and it was found that chromium sulfide and tungsten carbide were formed in the composite by adding molybdenum disulfide and graphite, which were responsible for lowfriction and high wear-resistance at elevated temperatures, respectively.
TL;DR: In this article, a Nd:YAG laser was used to generate micropores on T8 steel surface and the structure and morphology features of surface micropore were observed.
TL;DR: The results reveal the channels of as-synthesized mesoporous silica are essentially grafted with abundant amino groups and loaded with Cr(VI).
TL;DR: A delay-dependent condition guaranteeing the global exponential stability of the concerned neural network is obtained in terms of a linear matrix inequality, which is less conservative than some previous ones in the literature.
TL;DR: It is found that not only phase matching but also loss matching plays an important role in leaky mode coupling and some perturbation in dispersion curves for the two phase matching leaky modes when their losses are not equal.
Abstract: It is possible for core leaky mode to couple with cladding defect leaky mode when the cladding defect is close to fiber core. Dispersion properties and propagation loss of core mode will be affected in some extent once the coupling occurs. But a complete coupling between two leaky modes not always happens even the phase matching condition is satisfied. Leaky mode coupling in photonic crystal fiber with a hybrid cladding which includes low-index and high-index inclusions at the same time is numerically investigated based on a full vector finite element method. It is found that not only phase matching but also loss matching plays an important role in leaky mode coupling. The originally intersecting dispersion curves for the two leaky modes will split and become another two new curves due to the anti-crossing effect when both the real and imaginary parts of their mode effective refractive indices are equal. There is not splitting but some perturbation in dispersion curves for the two phase matching leaky modes when their losses are not equal. A theoretic explanation is also given to these phenomena.
TL;DR: Experimental results demonstrated that NaOH concentrations in initial gel played an important role in synthesis of pure-form zeolite A using fly ash as raw materials, and it was found that the higher NaOH concentration was used, the shorter crystallization time of zeolites A was required and the narrower particle size distribution of zeolia A was achieved.
15 Dec 2008
TL;DR: The class information is incorporated into the framework of CCA, and a novel method of combined feature extraction for multimodal recognition, called discriminative canonical correlation analysis (DCCA), is proposed and the experiments show that DCCA outperforms some related methods of both unimodal Recognition and multimodAL recognition.
Abstract: Multimodal recognition is an emerging technique to overcome the non-robustness of the unimodal recognition in real applications. Canonical correlation analysis (CCA) has been employed as a powerful tool for feature fusion in the realization of such multimodal system. However, CCA is the unsupervised feature extraction and it does not utilize the class information of the samples, resulting in the constraint of the recognition performance. In this paper, the class information is incorporated into the framework of CCA for combined feature extraction, and a novel method of combined feature extraction for multimodal recognition, called discriminative canonical correlation analysis (DCCA), is proposed. The experiments show that DCCA outperforms some related methods of both unimodal recognition and multimodal recognition.
TL;DR: The simulation results demonstrate that the maximal applications of quarantining and isolation strategies in the early stage of the epidemic are of very critical impacts in both cases of optimal and sub-optimal control.
TL;DR: In this paper, a delay-dependent bounded real lemma (BRL) for singular systems with a time delay is proposed, which guarantees a singular system to be regular, impulse free and stable while satisfying a prescribed H∞ performance level for any delays smaller than a given upper bound.
Abstract: This paper is concerned with establishing a delay-dependent bounded real lemma (BRL) for singular systems with a time delay. Without resorting to any bounding techniques for some cross terms and model transformation, a new version of BRL for such systems is proposed, which guarantees a singular system to be regular, impulse free and stable while satisfying a prescribed H∞ performance level for any delays smaller than a given upper bound. Based on this, an H∞ state feedback controller is designed via a linear matrix inequality approach. The BRL, stability as well as H∞ results developed in this paper are less conservative than existing ones in the literature, which is demonstrated by providing some numerical examples. Copyright © 2007 John Wiley & Sons, Ltd.
TL;DR: A new effective multiple kernel learning algorithm that can maximally correlate the m views in the transformed coordinates and introduces a special term called Inter-Function Similarity Loss RIFSI into the existing regularization framework so as to guarantee the agreement of multiview outputs.
Abstract: In this paper, we develop a new effective multiple kernel learning algorithm. First, we map the input data into m different feature spaces by m empirical kernels, where each generated feature space is taken as one view of the input space. Then, through borrowing the motivating argument from Canonical Correlation Analysis (CCA) that can maximally correlate the m views in the transformed coordinates, we introduce a special term called Inter-Function Similarity Loss RIFSI. into the existing regularization framework so as to guarantee the agreement of multiview outputs. In implementation, we select the Modification of Ho-Kashyap algorithm with Squared approximation of the misclassification errors (MHKS) as the incorporated paradigm and the experimental results on benchmark data sets demonstrate the feasibility and effectiveness of the proposed algorithm named MultiK-MHKS.
TL;DR: In this article, the results of a study on identifying the thermal conduction mechanism of nano-sized SiC/diglycidyl ether of bisphenol-A glycidol ether epoxy resin/2-ethyl-4-methylimidazole (nano-SiC/DGEBA/EMI-2,4) composites were presented.
TL;DR: In this article, a transfer matrix method of linear multibody system (MSTMM) is proposed to solve the eigenvalue problem of linear hybrid multi-body systems.
Abstract: A new method for linear hybrid multibody system dynamics is proposed in this paper. This method, named as transfer matrix method of linear multibody system (MSTMM), expands the advantages of the traditional transfer matrix method (TMM). The concepts of augmented eigenvector and equation of motion of linear hybrid multibody system are presented at first to find the orthogonality and to analyze the responses of the hybrid multibody system using modal method. If using this method, the global dynamics equation is not needed in the study of linear hybrid multibody system dynamics. The MSTMM has a small size of matrix and higher computational speed, and can be applied to linear multi-rigid-body system dynamics, linear multi-flexible-body system dynamics and linear hybrid multibody system dynamics. This method is simple, straightforward, practical, and provides a powerful tool for the study on linear hybrid multibody system dynamics. This method can be used in the following: (1) Solve the eigenvalue problem of linear hybrid multibody systems. (2) Obtain the orthogonality of eigenvectors of linear hybrid multibody systems. (3) Realize the accurate analysis of the dynamics response of linear hybrid multibody systems. (4) Find the connected parameters between bodies used in the computation of linear hybrid multibody systems. A practical engineering system is taken as an example of linear multi-rigid-flexible-body system, the dynamics model, the transfer equations and transfer matrices of various bodies and hinges; the overall transfer equation and overall transfer matrix of the system are developed. Numerical example shows that the results of the vibration characteristics and the response of the hybrid multibody system received by MSTMM and by experiment have good agreements. These validate the proposed method.
TL;DR: In this article, the analytical equivalence of the SIW and the RW of the solid wall is established on comparing the surface impedances along the side walls, of the SiW and of an RW through analytical continuation.
Abstract: Rectangular waveguide (RW) with sidewalls of vertical conducting cylinders (i.e. SIW, substrate-integrated waveguide) becomes popular with the advent of low-temperature co-fired ceramic structure; its analysis is usually numerical, or modal, leading to empirical design formulas. However, its analytical equivalence to the common RW of the solidwall is identified; in other words, analytical design formulas of the SIW and the equivalent RW of solid sidewalls are the same. The equivalence is established on comparing the surface impedances along the side walls, of the SIW and of an RW through analytical continuation. The equivalence formulas, propagation and cut off frequency show very good agreement with the results from both numerical simulations and measurements of hardware experiments, and over wide frequencies. The good agreements are easily understood on the basis of the conformal maps and the variational principle.
TL;DR: A series of curcumin analogues with more stable chemical structures were synthesized and several compounds showed an enhanced ability to inhibit lipopolysaccharide (LPS)-induced TNF-alpha and IL-6 synthesis in macrophages.
TL;DR: It was observed that part of the derivatives displayed significant activity when compared with curcumin and most of them exhibited activity against the ampicillin-resisted Enterobacter cloacae.
Abstract: The synthesis of three series of curcumin analogues with mono-carbonyl is described. Their in vitro anti-bacterial activities against seven Gram-positive and Gram-negative bacteria were tested and the effect of substituents on the aryl ring and the space structure of the linking strain were discussed. It was observed that part of the derivatives displayed significant activity when compared with curcumin and most of them exhibited activity against the ampicillin-resisted Enterobacter cloacae. Compounds A12, B09, B13, B14 and C09 show remarkable antibacterial activity in vitro. The result showed that heterocycle or long-chain substituents may enhance the activity of curcumin analogues.
TL;DR: In this article, a basic functionalized ionic liquid, 1-butyl-3-methyl imidazolium hydroxide ([bmim]OH), catalyzed three-component condensation reaction of aromatic aldehydes, malononitrile and α- or β-naphthol was used.
TL;DR: In this paper, a task-specific ionic liquid was synthesized and used as catalyst in the Knoevenagel condensation reaction of various kinds of aromatic aldehydes with ethyl cyanoacetate or malononitrile.
TL;DR: In this article, the twin lamella angle follows a normal distribution with the maximum along the loading axis in tension but not in compression, and different textured samples preparation via two different routes follow the Hall-Petch relation with similar slopes but exhibit an ∼50 MPa gap in yield stress.