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Showing papers by "Nanchang University published in 2002"


Journal ArticleDOI
TL;DR: The propagation of a pulse through one-dimensional photonic crystals that contain a dispersive and absorptive defect layer doped with two-level atoms is discussed and superluminal negative group velocity is discovered.
Abstract: The propagation of a pulse through one-dimensional photonic crystals that contain a dispersive and absorptive defect layer doped with two-level atoms is discussed. The dynamical evolution of the pulse inside the photonic crystal is presented. Superluminal negative group velocity (the peak appears at the exit end before it reaches the input end) is discovered. Although the group velocity is larger than c and even negative, the velocity of energy propagation never exceeds the vacuum light speed. The appearance of the superluminal advance or subluminal delay of the pulse peak inside the photonic crystal or at the exit end is due to the wave interference from Bragg reflections.

151 citations


Journal ArticleDOI
TL;DR: A neutral receptor with a rigid hydrazine spacer, N-p-(dimethylamino)benzamido-N'-phenylthiourea, was prepared and its dual fluorescence in acetonitrile was found to show response toward the presence of anions with high sensitivity and selectivity toward AcO(-).

130 citations


Journal ArticleDOI
TL;DR: In this paper, the photocatalytic transformation of rhodamine B (Rh B) and its effect on the hydrogen evolution over Pt/TiO2 have been examined.
Abstract: In the presence of electron donors, oxalic acid, ethanol and disodium ethylene-diamine tetraacetate (EDTA), the photocatalytic transformation of rhodamine B (Rh B) and its effect on photocatalytic hydrogen evolution over Pt/TiO2 have been examined. UV–Vis and fast atom bombardment mass spectrometry (FABMS) evidences demonstrate that two reductive reaction paths (photocatalytic hydrogenation and additive combination of Rh B with ethanol radical) take place over Pt/TiO2 in the reaction system. The adsorption behavior of Rh B on Pt/TiO2 with coexisting electron donors is a key factor for the transformation. As a result of the hydrogenation and the addition of ethanol radical, the rates of photocatalytic hydrogen generation by the donors decrease notably. A possible reaction mechanism is discussed.

100 citations


Journal ArticleDOI
TL;DR: In this article, the authors used an orthogonal array design to build a calibration data set consisting of absorption spectra collected in the 370-760nm range from solution mixtures containing the five metal ions earlier.

69 citations


Journal ArticleDOI
TL;DR: In this paper, a simple straightforward proof is presented to show that Hencky's elasticity model is exactly a hyperelasticity model, derivable from a quadratic potential function of the H-strain tensor.
Abstract: Hencky's elasticity model is an isotropic finite elasticity model assuming a linear relation between the Kirchhoff stress tensor and the Hencky or logarithmic strain tensor. It is a direct generalization of the classical Hooke's law for isotropic infinitesimal elasticity by replacing the Cauchy stress tensor and the infinitesmal strain tensor with the foregoing stress and strain tensors. A simple, straightforward proof is presented to show that Hencky's elasticity model is exactly a hyperelasticity model, derivable from a quadratic potential function of the Hencky strain tensor. Generally, Hill's isotropic linear hyperelastic relation between any given Doyle-Ericksen or Seth-Hill strain tensor and its work-conjugate stress tensor is studied. A straightforward, explicit expression of this general relation is derived in terms of the Kirchhoff stress and left Cauchy-Green strain tensors. Certain remarkable properties of Hencky's model are indicated from both theorectical and experimental points of view.

64 citations


Journal ArticleDOI
TL;DR: In this article, the intramolecular charge transfer (ICT) dual fluorescence of p -dimethylaminobenzamide (DMABA) in acetonitrile was found to show highly sensitive response to HSO 4 − over several other anions such as H 2 PO 4 −,AcO − and ClO 4 −.

62 citations


Journal ArticleDOI
TL;DR: A more general form of vector equilibrium problems with a moving ordering cone and set-valued mappings is introduced, and some existence theorems for generalizedvector equilibrium problems are obtained, which extend and unify some existence results for similar problems.
Abstract: In this paper, we introduce a more general form of vector equilibrium problems with a moving ordering cone and set-valued mappings, and obtain some existence theorems for generalized vector equilibrium problems, which extend and unify some existence results for similar problems.

59 citations


Journal ArticleDOI
TL;DR: In this paper, a new approach was proposed to find the optimal gate and vent locations for two-dimensional or two-and-a half-dimensional parts based on the mesh distance concept, with the objective of minimizing the maximum distance between gates and vents and avoiding dry spot formation.
Abstract: Resin transfer molding (RTM) is considered a promising manufacturing process for high performance composite materials. In the RTM process, gate/vent location is one of the most important variables in process design. It has a great impact on mold filling time and resin flow pattern, thus affects the process efficiency and product quality. Many studies have been conducted on optimization of RTM mold filling process to determine the locations of gates and vents. Most of them approached the optimum process design problem via numerical method-based process simulations. Due to the extensive computations involved, such approaches are difficult to be implemented for large and complex parts. This paper introduces a new approach to optimum arrangement of gates and vents for two-dimensional or two and a half-dimensional parts based on the mesh distance concept. With the assumption that the resin first fills the nodes closest to gates, the vent locations that minimize the area of trapped air can be determined. With the objective of minimizing the maximum distance between gates and vents and avoiding dry spot formation, genetic algorithm was employed to carry out the gate location optimization. The new RTM process design approach was tested on numerous cases obtained from the literature. It was found that the new approach was very efficient and effective in finding the optimal locations for gates and vents. The resulting gate and vent locations lead to satisfactory process performance as indicated by the optimal process performance index. The computational time required by the new approach was only a fraction of that reported by those simulation-based methods in the literature.

58 citations


Journal ArticleDOI
TL;DR: In this article, the influence of quantum degeneracy on the performance of a Stirling refrigeration cycle is investigated, based on the equation of state of an ideal Fermi gas.

47 citations


Journal ArticleDOI
TL;DR: In this article, the thermodynamic properties of dielectric materials are analyzed in detail, based on the Curie law, Curie-Weiss law and other relations between the electrical polarization and the electric field strength.

36 citations


Journal ArticleDOI
TL;DR: In this paper, the performance of the Fermi Ericsson refrigeration cycle using an ideal Fermis gas as the working substance was examined, and the inherent regenerative losses and the coefficient of performance (COP) of the cycle were calculated.
Abstract: The performance of the Ericsson refrigeration cycle using an ideal Fermi gas as the working substance, which is simply referred to as the Fermi Ericsson refrigeration cycle, is examined, based on the equation of state of an ideal Fermi gas. The inherent regenerative losses and the coefficient of performance (COP) of the cycle are calculated. Three special cases are discussed in detail. It is found that under the conditions of low and high temperatures, the COP of the cycle is only a function of temperature, while under other conditions, the COP of the cycle is not only a function of temperature, but also is dependent on the pressures and other parameters. The results obtained here may reveal the general performance characteristics of the Fermi Ericsson refrigeration cycle.

Journal ArticleDOI
Xiaoshu Zeng1, Xiaogang Sun1, Guoan Cheng1, Xiaosong Yan1, Xianliang Xu1 
TL;DR: In this article, the authors discussed the influence of reactor diameters, catalyst constitution, and precursor flows on the yield and quality of the multi-walled carbon nanotubes (MWNTS).
Abstract: In this paper, we discussed the influence of reactor diameters, catalyst constitution, and precursor flows on the yield and quality of the multi-walled carbon nanotubes (MWNTS). The reactor diameters will affect the production efficiency of MWNT and make the quality of MWNT uneven. It will enhance the yield and improve the quality of the MWNT if the precursors are evenly sent into reactors along the direction of axis of reactors. Catalysts play an important role in promoting the yield and controlling the diameters of MWNT. The effect of catalysts will vary with different carbon precursors.

Journal ArticleDOI
01 Dec 2002-EPL
TL;DR: In this article, it was shown that the superluminal or sublumininal pulse propagation originates essentially from the interference of the different frequency components of the pulse, and that the coherence of the various frequency components plays an important role in superluminous propagation.
Abstract: The propagation of pulses through dispersive media was investigated by solving Maxwell's equations without any approximation. It was demonstrated that the superluminal or subluminal pulse propagation originates essentially from the interference of the different frequency components of the pulse. The coherence of the different frequency components plays an important role in superluminal propagation. When the pulse becomes partially coherent, the propagation changes from superluminal to subluminal. Since superluminality always exists as long as the spectrum of the coherent pulse is within the anomalously dispersive region whatever the shape of the pulse is, such a coherent pulse must be transmitted superluminally.

Journal ArticleDOI
TL;DR: In this article, the rheological behavior for thixocasting of semi-solid aluminum alloy (A356) is pseudoplastic at the shear rate of 2×103 to 104−s−1.

Book ChapterDOI
TL;DR: This paper presents an approach to reasoning about information granules based on a form of rough logic with formulas and constructed granules that are interpreted in the context of rough set theory.
Abstract: This paper presents an approach to reasoning about information granules based on a form of rough logic with formulas and constructed granules that are interpreted in the context of rough set theory. Rough logic is defined over a given information system IS=(U, A). The propositions (or predicates) of this logic are logical formulas defined by attributes in IS. The semantics of such propositions is defined in the context of subsets of the universe U.

Proceedings ArticleDOI
Qing Liu1, Qun Liu
04 Nov 2002
TL;DR: The paper proposes a granular logic which defines the syntax and semantics of the logic, and the formula in the logic is a granule or any Boolean combination of the granules.
Abstract: The paper proposes a granular logic which defines the syntax and semantics of the logic. The formula in the logic is a granule or any Boolean combination of the granules. We discuss a reasoning based on the granular computing. The reasoning is used in expert systems, and is also an extension of matching reasoning in production rules. The inclusion and closeness degree between granules are defined in the paper. Finding the match among granules satisfying the given closeness degree completes the approximate reasoning. The paper defines the granular operation based on both logic and the set theory. Finally, the matching reasoning and deductive inference is illustrated with real examples.

Proceedings ArticleDOI
19 Sep 2002
TL;DR: In this article, zone plates were designed and fabricated by photographic processing, which were used as radial shearing devices, and they were detected by a CCD camera and processed by a PC computer, and the fringe phase of shearing interferogram is evaluated by Fast Fourier transform (FFT) algorithm.
Abstract: In this paper, aspheric surface testing technique with radial shearing interferometer has been developed. Zone plates are proposed to construct radial shearing interferometer because of its stability and simplicity. Zone plates were designed and fabricated by photographic processing, which is used as radial shearing devices. Radial shearing interferogram are detected by a CCD camera and processed by a PC computer. Fringe phase of shearing interferogram is evaluated by Fast Fourier transform (FFT) algorithm. Wave aberration estimation method of aspheric surface is also presented, which is depended on polynomial expansion fitting. Some errors of interferometer are discussed. Finally, theoretical analysis and experimental results are compared, which shows its accuracy is less than λ/20.

Journal ArticleDOI
TL;DR: A method of estimating the critical rate of temperature rise for thermal explosion of first-order autocatalytic decomposition reaction systems using non-isothermal DSC is presented.

Journal ArticleDOI
TL;DR: Lanthanum orthoniobate (LaNbO4) has been synthesized through a new coprecipitation approach, and added to alumina to produce the composites by hot-press sintering as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, Fourier transform evaluation for moire deflectogram is proposed to automatically map the temperature field, which is generated by conventional deflectometer and analyzed by means of Fourier transformation algorithm.
Abstract: Fourier transform evaluation for moire deflectogram is proposed to automatically map the temperature field. The moire deflectogram is generated by conventional deflectometer and is analyzed by means of Fourier transform algorithm. The convolution backprojection algorithm is used for the optical tomography. Asymmetric 3-D gas temperature distribution for a given layer is reconstructed.

Journal ArticleDOI
TL;DR: In this article, a planar texture on top of the fiber texture was developed by applying a uniaxial strain during the thin film deposition process and some structural and kinetic features of the process were identified.

Journal ArticleDOI
TL;DR: In this paper, an iterative target transformation factor analysis (ITTFA) is explored to resolve the spectral interferences produced by the ultra-high-purity rare-earth matrices so as to facilitate the determination of the trace calcium.
Abstract: When trace elements present in complex matrices are analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES) correction must be made for the background if it overlaps with the desired trace analyte spectrum. However, often this is difficult to achieve because the required pure materials for the complex background matrix cannot be obtained, and hence the standard spectra are unavailable. A chemometrics solution to resolve the overlapping ICP-OES spectra of some such systems (gray systems) is proposed in this paper so as to obviate the need for the background standards. The case considered involves trace calcium in the presence of a large rare-earths background: Pr–Ca, Nd–Ca, Tb–Ca, Ho–Ca and Er–Ca. The application of iterative target transformation factor analysis (ITTFA) is explored to resolve the spectral interferences produced by the ultra-high-purity rare-earth matrices so as to facilitate the determination of the trace calcium. Once the ITTFA method has extracted the required background spectrum, a Kalman filter (KF) procedure is then used for the quantitative determination of the trace element. The calcium results are compared with those estimated by the conventional standard addition method, and improved results are observed. In addition, while in the absence of suitable standards such an approach is essential for the problem of the determination of the trace calcium in the rare-earth matrix described, this method should also be applicable to white systems, thereby often reducing costs of analysis as well as labour associated with the preparation of background material standards.

Journal ArticleDOI
TL;DR: In this paper, high concentration erbium doping in silicon-rich SiO2 thin films is demonstrated using metal vapor vacuum arc ion source implantation with relatively low ion energy, strong flux and very high dose.

Journal ArticleDOI
TL;DR: In this paper, the effect of samarium on Ni/sepiolite catalyst was investigated by benzene hydrogenation, methanation of carbon dioxide, CO chemisorption, XPS and CS2 poisoning, respectively.
Abstract: The effect of samarium on Ni/sepiolite catalyst was investigated by benzene hydrogenation, methanation of carbon dioxide, CO chemisorption, XPS and CS2 poisoning, respectively. The result indicates that a proper amount and impregnation order of samarium in the preparation of Ni-Sm/sepiolite catalyst are very efficient to improve the catalytic activity and anti-sulfur ability. At the same time, the mechanism of samarium improving hydrogenation activity of Ni/sepiolite is presented.

Journal Article
Wan Guo-jin1
TL;DR: A new way for image segmentation is introduced which using dynamic threshold combined with global threshold works better than the other two ways.
Abstract: The paper firstly discussed two ways for image segmentation:image segmentation by global threshold and image segmentation by dynamic threshold.If the background of an image is constant throughout the image,a global threshold may work well.In many cases,the background gray level is not constant,and the contrast of an object varies within the image.In these cases,we may use a threshold which is a slowly varied function of position in the image,that is,use a dynamic threshold.Because we must divide the image into sectors,the image divided by simple dynamic threshold usually includes shadow and man-made boundaries.To improve the effect of image segmentation,the paper introduced a new way for image segmentation which using dynamic threshold combined with global threshold.Examinations indicate that this way works better than the other two ways.

Journal ArticleDOI
TL;DR: Erbium and silicon were dual implanted into thermally grown SiO2 film on Si by a metal vapor vacuum arc ion source, followed by rapid thermal annealing at 900-1100°C for 20 minutes as discussed by the authors.

Journal Article
TL;DR: The chemical components of the leaves of Cyclocarya paliurus were investigated by solvent extraction and column chromatography and compounds I, II, III and IV were obtained for the first time from this plant.
Abstract: Objective To investigate the chemical components of the leaves of Cyclocarya paliurus Method The chemical components were isolated by solvent extraction and column chromatography The chemical structures were identified on the basis of physic-chemical constant and spectral data Result Six compounds were isolated and identified as kaempferol(I), quercetin(II), isoquercitrin(III), ellagic acid(IV), daucosterol(V) and cyclocaric acid B(VI) Conclusion Compounds I, II, III and IV were obtained for the first time from this plant

Journal ArticleDOI
TL;DR: In this article, 15 tris[(4-fluorophenyldimethylsilyl)methyl]tin O,O-dialkyldithiophosphates were synthesized and characterized by IR, 1H NMR, MS spectroscopy, x-ray diffraction, and elemental analysis.
Abstract: Fifteen new tris[(4-fluorophenyldimethylsilyl)methyl]tin O,O-dialkyldithiophosphates were synthesized and characterized by IR, 1 H NMR, MS spectroscopy, x-ray diffraction, and elemental analysis. The crystal structure of [(4-FC 6 H 4 SiMe 2 CH 2 ) 3 Sn] 2 O has been determined. The structure consists of four-coordinated tin atoms in a slightly distorted tetrahedral geometry with an O atom bridge between the two Sn atoms.

Journal Article
Huang Ju-hua1
TL;DR: The presented GA generates initial population in the searching set evenly when taking experience into account, can calculate fitness values of individuals adaptively, executes crossover operation using composite methods, can adapt rates of mutation and crossover dynamically and dwindles searching space adaptively.
Abstract: On the basis of comparing,analyzing and synthesizing some available modifications,this paper presents a series of modifications to SGA,and forms a highly effective synthetic GAThe presented GA generates initial population in the searching set evenly when taking experience into account,can calculate fitness values of individuals adaptively,executes crossover operation using composite methods,can adapt rates of mutation and crossover dynamically and dwindles searching space adaptivelyFinally,the validity of the presented GA is testified by two examples

Journal Article
TL;DR: The result showed that the could be successful for RAPD, when the concentration of EDTA in the extraction is 125mM 50μg DNA could be obtained from every gram Mycelia(wet weight) of Monascus and its molecular weight is about 25kb.
Abstract: The method of extraction and purification of DNA from Monascus with benzyl chloride was improved Furthermore,the influencing factors of the DNA extraction were studied,including the concentration of EDTA and other factors The result showed that the could be successful for RAPD,when the concentration of EDTA in the extraction is 125mM 50μg DNA could be obtained from every gram Mycelia(wet weight)of Monascus and its molecular weight is about 25kb The optimal amplification condition for RAPD-PCR was determined by orthogonal test:Mg 2+ 2 0mmol/l,dNTPs 0 15mmol/l,Taq polymerase enzyme 0 05U/μl,template DNA 1 2ng/μl,primer 0 36μmol/l,Tris-HCl 10mmol/l,pH 9 0,KCl 50mmol/l,Nonidet P40 0 1%