Showing papers by "Nanchang University published in 2000"

Generalized vector quasi-equilibrium problems

Abstract: The properly quasi-convexity of multivalued mappings in an ordered vector space is introduced. Existence theorems for generalized vector quasi-equilibrium problems and multivalued vector equilibrium problems are obtained.

Super Efficiency for a Vector Equilibrium in Locally Convex Topological Vector Spaces

Abstract: This paper deals with the vector equilibrium problem. The concept of super efficiency for vector equilibrium is introduced. A scalar characterization of super efficient solution for vector equilibrium is given. By using of the scalarization result, we discuss the connectedness of super efficient solutions set to the vector equilibrium problems in locally convex topological vector spaces.

Proper efficiency for set-valued vector optimization problems and vector variational inequalitiesRID="*"ID="*" This research was partially supported by the National Natural Science Foundation of P.R. China and the Natural Science Foundation of Jiangxi Province, P.R. China.

Abstract: We obtain the necessary and sufficient conditions of many kinds of proper efficiency in vector set-valued optimization by using the concept of contingent epiderivative introduced by Jahn and Rauh, also we disclose the closed relations between proper efficiency of vector set-valued optimization problem and proper efficiency of a certain kind of vector variational inequality.

Some theorems in the X-M-PN space

Abstract: A new concept of the X-M-PN space is introduced, and the acute angle principle in the X-M-PN space is proved. Meanwhile, some new results are obtained.

Subfringe integration method for automatic analysis of moire deflection tomography

Abstract: A new method of fringe analysis by subfringe integration al- gorithm (SIA) is proposed to analyze moire deflectograms and to map the phase object, in which the fringe phase is retrieved and phase object message is obtained automatically. Optical tomography is applied to the moire deflectometry for the measurement of asymmetric phase object. The convolution backprojection algorithm is used to obtain the 3-D tem- perature field. Theoretical analysis, experimental result and simulation calculations are presented. © 2000 Society of Photo-Optical Instrumentation Engi- neers. (S0091-3286(00)01310-6)

Space-like submanifolds with parallel mean curvature in de Sitter spaces

Abstract: Abstract This paper investigates complete space-like submainfold with parallel mean curvature vector in the de Sitter space. Some pinching theorems on square of the norm of the second fundamental form are given

Redundant transformation on the binary data and its applications to image coding and transmission

Abstract: Mojette transformation (MT) is the discrete domain counterpart of the Radon transformation, and the Mojette transformation on binary data has some special characteristics compared to the ones for integer data. This paper discusses the ability of reconstruction of Mojette transformation on binary data (MTBI) and finds out a group of projections by which Mojette transformation on a bilevel image of size 2/spl times/2 is reversible. Furthermore, this transformation has the ability of correcting 1 bit of error within a vector of 8 bits and some of 2-continuous-bits of errors. Finally, an application to state image coding and transmission is proposed.

Effect of microstructure on the hardening and softening behaviors of polycrystalline shape memory alloys part i:micromechanics constitutive modeling

Abstract: The effects of microstructure and its evolution on the macroscopic superelastic stress-strain response of polycrystalline Shape Memory Alloy (SMA) are studied by a microstructure-based constitutive model developed in this paper. The model is established on the following basis: (1) the transformation conditions of the unconstrained single crystal SMA microdomain (to be distinguished from the bulk single crystal), which serve as the local criterion for the derivation of overall transformation yield conditions of the polycrystal; (2) the micro- to macro-transition scheme by which the connection between the polycrystal aggregates and the single crystal microdomain is established and the macroscopic transformation conditions of the polycrystal SMA are derived; (3) the quantitative incorporation of three microstructure factors (i.e., nucleation, growth and orientation distribution of martensite) into the modeling. These microstructural factors are intrinsic of specific polycrystal SMA systems and the role of each factor in the macroscopic constitutive response is quantitatively modeled. It is demonstrated that the interplay of these factors will result in different macroscopic transformation kinematics and kinetics which are responsible for the observed macroscopic stress-strain hardening or softening response, the latter will lead to the localization and propagation of transformation bands in TiNi SMA.

ESR studies on the solvation of perfluoro-n-alkyl t-butyl nitroxides — A new scale for electronegativity of perfluoro-n-alkyl groups

Abstract: Pentafluoroethyl t-butyl nitroxides (3) have been generated by the use of electron-transfer reactions of O-benzoyl-N-t-butylhydroxylamine (1) and pentafluoropropanoyl peroxide (2) in F113 (CFCl2CF2Cl) solution. ESR measurement of aN and aF β values for 3 in 11 solvents have been carried out at 17 ± 2 °C. The aN values for 3 in 10 aprotic solvents (but not in i-PrOH) show a linear correlation with the cybotactic solvent parameter ET, i.e. aN = 3.02 × 10−2 ET ± 10.46. Together with the similar correlation analysis for trifluoromethyl t-butyl nitroxide (4) and heptafluoropropyl t-butyl nitroxide (5) reported previously, the physical significance for the slope, slope × ET, the extrapolated intercept on the aN axis, is linked to the sensitivity of the nitroxide toward solvation, the magnitude of the overall solution effect on the aN values, and the intrinsic aN values of 3, 4, 5 in the ideal gaseous state, respectively. The intercepts on the aN axis, 11.34 G, 11.56 G and 11.37 G may serve a new measure of electronegativity for CF3, C2F5 and n-C3F7, respectively. The plots of aN versus noncybotactic solvent constants, such as dipolar moment (μ) and dielectric constant (ɛ), all show random cases.

A Vector Variational-Like Inequality for Compact Acyclic Multifunctions and its Applications

Abstract: A vector variational-like inequality for compact acyclic multifunctions is presented. This is used to introduce the generalized vector quasi-variational inequality and the generalized vector quasi-complementarity problem in ordered vector spaces. Some existence theorems for these problems are proved.

Effect of microstructure on the hardening and softening behaviors of polycrystalline shape memory alloys part II numerical simulation under axisymmetrical loading

Abstract: Based on the microstructure-based constitutive model established in Part I, a detailed numerical investigation on the role of each microstructure parameter in the kinematical and kinetic evolution of polycrystalline SMA under axisymmetrical tension loading is performed. Some macroscopic constitutive features of stress-induced martensite transformation are discussed.

lambda-Level Rough Equality Relation and the Inference of Rough Paramodulation

Abstract: In the paper, it defines a λ-level rough equality relation in rough logic and establishes a rough sets on real-valued information systems with it. We obtain some related properties and relative rough paramodulation inference rules. They will be used in the approximate reasoning and deductive resolutions of rough logic. Finally, it proves that λ-level rough paramodulant reasoning is sound.

A tribological study of a ternary complex of zinc with dioxyethylenated octylphenol phosphate in water

Abstract: A novel aqueous antiwear additive, a ternary complex of zinc with dioxyethylenated octylphenol phosphate and triethanolamine (TXOZ + TEA), has been synthesised. Its tribological behaviour in water was evaluated using a four-ball tester. The results indicate that the complex in water exhibits higher load-carrying capacity than mineral oil plus ZDTP, and excellent antiwear behaviour. The elemental composition of its rubbed surface was investigated with Auger electron spectroscopy (AES), and the results of this analysis are presented in the paper. The action mechanism of the additive is also discussed.

Up-conversion luminescence from neodymium ion implantation silicon

Abstract: Strong ultra-violet and visible frequency up-conversion fluorescence spectroscopy in neodymium-ion implantation single crystalline silicon at the excitation wavelengths of 625, 650, 675 and 700 nm, was experimentally investigated. The PL intensity increased with the increase in the excitation wavelength and ion fluence. The photoluminescence excitation (PLE) spectrum in the wavelength range of 500–770 nm was also studied. For 700-nm pumping, a mechanism of two-photon absorption and radiation transition process was proposed.

GaN: Si Single Crystal Films Grown on Sapphire Substrates by MOCVD

Abstract: Si-doped GaN was grown by MOCVD method using a home-made vertical reactor operating at atmospheric pressure. To prevent parasitic reactions in the gas phase, reagents were mixed at 20mm before reaching the substrate. The growth was carried out on (0001 ) oriented sapphire substrates using Trimethylgallium(TMGa) and blue-ammonia(NHs) as Ga and N sources, respectively. The doping reagents was the diluted silane(SiH4). The mixed gases of hydrogen and nitrogen were used as the carrier gases. A thin buffer layer with thickness of about 15um was grown at 520℃ and recrystallized at 1 060℃for 6 minutes. The Sidoped GaN films were grown at 1 060℃with the [ V ]/[ Ⅲ] ratio of 1 000: 1 The growth time was an hour with the growth rate in the rage of 1. 8 - 4. 0 um/h. The photoluminescence (PL ), the Van der Pauw Hall method, and the double-crystal X-ray diffraction(DXRD) were used to measure the optical, electrical, and structural data of these films at room temperature. Table 1 is the characterization data of the Si-doped GaN films. Fig. 1 shows the electron carrier concentration and mobility of Si-doped GaN as a function of SiH4/ TMGa ratio. The carrier concentration varies between 1 ×1017 and 4 ×1019cm - 3. The relationship between the carrier concentration and the flow rate ratio of SiH4/TMGa is approximately linear. Fig. 2 shows the photoluminescence (PL) spectra of Si-doped GaN as a function of the SiH4/TMGa ratio at 300K. The excitation-source was a 15mW He-Cd laser. The band-edge emission and deep-level emission were observed around 370um and 550um, respectively. Very strong band-edge emission without yellow band(limited by the apparatus)was observed in Fig. 2-D. Fig.3 shows the intensity of band-edge emission, the intensity ratio between band-edge emission and deep-level emission as a function of the carrier concentration of Si-doped GaN films. The intensity of bandedge emission was highly enhanced and the intensity of yellow emission was restrained with the increasing ofcarrier concentration. As shown in Fig. 3, Si-doped GaN films, with carrier concentration of 2 ×1019cm-3 were obtained. For this kind of film, the intensity of band edge emission is as high as one hundred times of that of unintentional doped GaN and no yellow luminescence can be found. Fig.4 shows the relationships between the SiH4/TMGa ratio and the FWHM of double-crystal x-ray diffraction (DXRD ) and the growth rate of Si- doped GaN films. The FWHM of DXRD of GaN films became wider when SiH4/TMGa ratio increased. However, the growth rate decreased from 4 um/h to 1 .7um/h with increasing SiH4/TMGa ratio. This phenomenon has not been reported to our knowledge. In this paper, Si-doped GaN films with carrier concentration of 2 ×1019 cm-3, electron mobility of 120.m2/V.s can be obtained. FOr this kind of film, FWHM of the band edge emission at room temperature is only 60meV, and no yellow emission can be observed. In this work, the optimum flow ratio of SiH4/TMGa was 2 ×10 -4.

Experimental study on elastoplastic buckling strength of web in i-section girder

Abstract: The elastoplastic buckling strength of the web in I-section steel girder under pure bending was studied experimentally, the comparison between experimental and theoretical results was made. The influence of stiffness of longitudinal stiffener on buckling coefficients of the girder web was analyzed. And the reasonable ratios of height to thickness of the web were given and some items of the Chinese "Code for Design of Steel Structures" were discussed.

Super efficiency and its scalarization in topological vector space

Abstract: In this paper, we give a characterization of super efficiency, and obtain a scalarization result for super efficiency in locally convex locally bounded topological vector spaces. The proof given here is substantially different from that given by Borwein and Zhuang.

Simplifications of formulas for calculating transmission losses and incremental transmission losses in rectangular coordinate impedance matrix method

Abstract: The comparatively complete formulas for calculating incremental transmission losses with rectangular coordinate impedance matrix method are derived in this paper. Then according to assumptions, the formulas are simplified in seven ways and the double summing items in some of them are eliminated or omitted. In addition, the formulas for calculating transmission losses are also simplified.

Surface properties of Nb+C ion co-implanted stainless steel

Abstract: The surface properties of Nb+C co-implanted stainless steel have been studied. The co-implantation of Nb+C ions was carried out using a modified cathode of a metal vapor vacuum arc (MEVVA) source ion implanter. The results of the experiment showed that the properties of wear resistance and the hardness in the co-implanted surface layer were improved. The dislocation network and tangle were observed by TEM. The dispersion hardening phases were determined by XRD and TEM to be Fe2Nb, Cr23C6, Cr3C2 and Fe5C2. Therefore, dispersion hardening and dislocation hardening were expected. The results were also compared with those of Nb+C ion dual implantation. This showed that there were some unique advantages to co-implantation.

Computer aided type test system for electric machine

Abstract: A microcomputer is adopted as the measure and control center of a computer-aided type test system. This paper introduces the structure and principle of the system and emphasises the untouched temperature testing technology for rotor.

Research in the application of ASVG in Jiangxi Electric Power System

Abstract: Aiming at the defects of low voltage level and poor transient stability, the authors choose advanced static VAr generation (ASVG), one of the key devices in flexible alternating current transmission systems (FACTS), to study the effect of the application of FACTS on China's Jiangxi electric power system. In this paper, the Power System Toolbox (POWERSYS) of MATLAB is used to construct an ASVG control system. With this system, the steady state operation of ASVG under balanced system voltage and the reactive power controller of ASVG is simulated. The User Program Interface of the Power System Application Software Package (PSASP/UPI) developed by EPRI of China is used to work out the user program of ASVG, and the result of its application in the Jiangxi electric power system is satisfactory.

Phase transformation of a CuZnAl alloy during friction

Abstract: Changes in compositions and microstructures in the surface layer of a Cu-Zn-Al shape memory alloy during friction were investigated by means of scanning electron microscopy, electron probe microanalysis (EPMA), X-ray diffraction, and transmission electron microscopy. It has been found that in friction, single M18R martensite β′ transforms into α+β, with the shape and distribution of the new phases varying with the conditions of friction. In mild friction, Zn and Al diffuse over short distances along the sliding direction, resulting in a structure in which needlelike β and α alternate along the sliding surface. In severe friction, where higher surface temperatures and temperature gradients are expected, Zn and Al make long-distance uphill diffusion from inside toward the surface. Consequently, Zn and Al are concentrated on the surface and depleted in the subsurface, and the phase layers present from the outmost surface inward are β, α, α+β, cross-martensite, and the matrix.

La-implanted Si-based emitting film materials

Abstract: The photoluminescence (PL) spectra at room temperature for monocrystal Si wafer thermal oxide Si samples doped by La ion implantation are measured. The results show that all the samples possess blue-violet photoluminescence properties under the UV light excitation and its light emission is stable. The intensity of PL peaks increases with the increasing of La ion dose during ion beam synthesis within a certain limits. Moreover, PL is closely related to the temperature of rapid thermal annealing. Besides, the feature and appearance of the samples was surveyed, with atomic force microscopy. The photoluminescence mechanisms for our samples is also discussed.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A method developed for predicting potential precursors of earthquakes

Abstract: This paper describes the methodology used to eliminate environmental effects to a time series of short distance (24m) leveling across a geological fault in order to detect potential precursors of earthquakes from the residual time series. First, linear trends and periodic signals are removed from the observations with the help of a recursive least squares method. Then, a controlled autoregression model is used to predict the environmental contribution due to precipitation and evaporation. The difference between the leveling data and these predictions are considered to be due to endogenic crustal processes. Applying this methodology to leveling data of approximately 13 years at Niukouyu crustal deformation station near Beijing reveals an anomalous deformation before the Tangshan earthquake (M7.8), which has its epicenter about 180 km from the survey site. However, in the time period considered, another anomaly occurred which cannot be related directly to a seismic event.

A speedup method for fractal encoding of digital signals

Abstract: A fast fractal encoding method for one dimensional digital signals is given, in which the local extremum points of the data sequence to be encoded are firstly determined, and then the optimum interpolation points for fractal encoding are searched in the extremum-points pool. In this way, the search space of the interpolation points is considerably reduced. Experimental results show that the encoding speed is greatly increased, whereas the signal compression ratio and the reconstruction quality of signals are comparable to that of similar researches.

The existence and uniqueness of solutions of generalized variational inequalities arising from elasticity with friction

Abstract: The existence and uniqueness of solutions of generalized variational inequalities arising from elasticity with friction, which is equivalent to corresponding elemental problems, is elucidated in detail, and then FEM approximation and discrete methods are proposed.