Showing papers by "Beijing University of Technology published in 2003"
TL;DR: In this paper, a mild hydrothermal method using an aqueous solution of bismuth nitrate and two different vanadium sources (V 2 O 5 and NaVO 3 ) was used to obtain phase pure BiVO 4 powders.
Abstract: Monoclinic bismuth vanadate (BiVO 4 ) powders were prepared by a mild hydrothermal method, using an aqueous solution of bismuth nitrate and two different vanadium sources (V 2 O 5 and NaVO 3 ) The characterization of as-prepared BiVO 4 was carried out by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) The results revealed that in the present work the temperature of 200 and 140 °C are sufficient to prepare phase pure BiVO 4 powders from V 2 O 5 and NaVO 3 , respectively The BiVO 4 sample prepared from V 2 O 5 consists of an agglomeration of small rod-like particles When BiVO 4 was prepared from NaVO 3 , monoclinic BiVO 4 powder with a plate form is obtained
186 citations
TL;DR: In this article, chemical bath deposition of zinc sulfide thin films using mixed aqueous solutions of zinc acetate, thiourea and tri-sodium citrate was used as the complexing agent.
Abstract: Crystalline zinc sulfide (ZnS) thin films were prepared by chemical bath deposition (CBD) using the mixed aqueous solutions of zinc acetate, thiourea and tri-sodium citrate, where tri-sodium citrate was used as the complexing agent. The thin films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption. The as-deposited thin films were surface homogeneous with pure wurtzite structure and the optical band gap of the film was estimated to be 3.53 eV.
145 citations
TL;DR: To the authors' knowledge this is the first report of the use of a Nd:GdVO4 crystal for mode locking with a semiconductor saturable absorber mirror.
Abstract: We report an end-pumped and passive mode-locking all-solid-state laser. The laser consists of a Nd:GdVO4 crystal and a linear resonator with a semiconductor saturable absorber mirror that yield mode locking. We achieved stable continuous-wave mode locking with an 8-ps pulse duration at a 154-MHz repetition rate. The average output power was 600 mW with 4 W of pump power. To our knowledge this is the first report of the use of a Nd:GdVO4 crystal for mode locking with a semiconductor saturable absorber mirror. (C) 2003 Optical Society of America.
80 citations
TL;DR: In this paper, a sequencing batch reactor (SBR) of biofilm formed on fibrous carriers was used for phosphorus removal from wastewater when conditions included a 30% packing ratio for the carriers and 9-h hydraulic retention time.
73 citations
19 Dec 2003
TL;DR: The model of optimum route selection used for the system is built based on the analysis of unblocked reliability and the circuitous length, which can provide the reasonable route guidance to the traveler even without real time traffic information.
Abstract: Vehicle automatic navigation system plays an important role in intelligent transportation system, the model of optimum route selection used for the system is built in the paper Considering the randomicity of traffic demand and supply, the unblocked reliability of the road is used to dispose the uncertainty of the congestion happening Taking advantage of historical data and experience, the optimum route can be decided based on the analysis of unblocked reliability and the circuitous length, which can provide the reasonable route guidance to the traveler even without real time traffic information
65 citations
TL;DR: In this article, an anisotropic Nd/sub 15.0/Fe/sub 72.7/Co/sub 3.8/Al/sub 1.0 magnet was produced by the spark plasma sintering technique.
Abstract: We have produced an anisotropic Nd/sub 15.5/Dy/sub 1.0/Fe/sub 72.7/Co/sub 3.0/B/sub 6.8/Al/sub 1.0/ magnet by the spark plasma sintering (SPS) technique and compared it with a magnet of the same composition processed by the conventional sintering method. We investigated magnetic properties, microstructure, and constituents by a B-H loop-line instrument, a scanning electron microscope, and an energy-dispersive X-ray detector, and studied the effects of processing conditions on the magnetic properties, dimensional precision, and density. We also examined the magnet's electrochemical properties in electrolytes and its corrosion behavior in oxidizing environments. We found that the microstructure of the SPS NdFeB magnet is different from that of the conventional one. In the SPS-processed magnet, the grain size is fine and uniform while the distribution of the Nd-rich phase is heterogeneous. The SPS NdFeB magnet has a maximum energy product of 240 kJ/m/sup 3/ and a coercive force of 1260 kA/m. The density of the magnet reaches 7.58 g/cm/sup 3/, and its dimensional precision is about 20 /spl mu/m. The electrochemical properties and the corrosion resistance of the SPS NdFeB magnet are better than those of the conventional one. The SPS process is a promising method for the production of NdFeB magnets with ideal overall performance.
53 citations
TL;DR: In this article, the structure and morphology of the obtained γ-MnS film were characterized, and the results showed that the film was composed of asymmetric hexagonal crystals with a size of 500-1000 nm.
Abstract: Well-crystallized γ -MnS films in a pure phase have been deposited on commercial glass substrates by chemical bath deposition. The structure and morphology of the obtained γ -MnS film were characterized, and the results showed that the film was composed of asymmetric hexagonal crystals with a size of 500–1000 nm. The photoluminescence of the γ -MnS film has been studied from 295 K down to 30 K and exhibited two emission bands centered at 1.8 and 1.66 eV, respectively. The temperature dependence of photoluminescence was also observed and interpreted using the spin-wave-assist photoluminescence model.
51 citations
26 May 2003
TL;DR: An overview on the recent development in data mining applications for direct marketing for marketing discipline for business intelligence is provided.
Abstract: Direct marketing is a new business model by an interactive one-to-one communication between marketer and customer. There is great potential for data mining to make useful contributions to the marketing discipline for business intelligence. This paper provides an overview on the recent development in data mining applications for direct marketing.
41 citations
TL;DR: This paper gave central limit theorems for generalized set-valued random variables whose level sets are compact both in R d or in a Banach space under milder conditions than those obtained recently by the latter two authors.
32 citations
TL;DR: In order to achieve fuzzy control of nitrification in a Sequencing Batch Reactor (SBR) brewery wastewater, the effect of alkalinity on pH variation during nitrification was systematically studied and the variations of DO and ORP were investigated.
31 citations
TL;DR: In this paper, a numerical simulation method is used to study the effect of specimen size on interfacial behavior of the specimen in fiber pullout tests, where all materials are assumed to be linear and elastic solids, and the effects of thermal residual stress and friction between crack faces are ignored.
TL;DR: In this paper, it was shown that hour glass-shaped ZnO powders are asymmetric both in shape and stoichiometry: while the atomic ratio of O/(Zn+O) at the bigger end ranges from about 60% to 40% along the polar axis of the hour-glass-shaped crystallites, at the smaller end remains almost constant at approximately 50%.
Abstract: Well crystallized ZnO powders with various morphologies such as hour glass-shaped, shortened prismatic, flake-like and prismatic form have been synthesized by adopting the system of Zn(Ac) 2 -KOH-H 2 O via a hydrothermal process at 200°C for 2 h. It was found that the as-synthesized hour glass-shaped ZnO crystallites are asymmetric both in shape and stoichiometry: while the atomic ratio of O/(Zn+O) at the bigger end ranges from about 60% to 40% along the polar axis of the hour glass-shaped ZnO crystallites, the atomic ratio of O/(Zn+O) at the smaller end remains almost constant at approximately 50%.
TL;DR: Different morphologies of nanostructured bismuth sulfide (Bi2S3) including nanorods, nanoparticles and bundles of nanorod have been prepared successfully by an ultrasonic-assisted liquid phase method and a hydrothermal, surfactant-assisted solvothermal method, respectively as mentioned in this paper.
Patent•
31 Dec 2003TL;DR: In this paper, the authors proposed Er-containing aluminum alloys with greatly improved strength properties without significant deterioration of the toughness, and the present application provides Al-Zn−Mg−Er and Al-Mg-Er series aluminum alloy, the mechanical properties of which are improved by the addition of Er.
Abstract: The present invention relates to Er-containing aluminum alloys with greatly improved strength properties without significant deterioration of the toughness. Specifically, the present application provides Al—Zn—Mg—Er and Al—Mg—Er series aluminum alloys and Al—Mg—Li—Zr—Er series alloys, the mechanical properties of which are improved by the addition of Er.
13 Oct 2003
TL;DR: This work builds a customer model based on Bayesian network by learning from customer shopping history data and presents a recommendation algorithm based on probability inference in combination with the last shopping action of the customer which can effectively and in real time generate a recommendation set of commodity.
Abstract: As e-commerce developing rapidly, it is becoming a research focus about how to capture or find customer's behavior patterns and realize commerce intelligence by use of Web mining technology. Recommendation system in electronic commerce is one of the successful applications that are based on such mechanism. We present a new framework in recommendation system by finding customer model from business data. This framework formalizes the recommending process as knowledge representation of the customer shopping information and uncertainty knowledge inference process. In our approach, we firstly build a customer model based on Bayesian network by learning from customer shopping history data, then we present a recommendation algorithm based on probability inference in combination with the last shopping action of the customer, which can effectively and in real time generate a recommendation set of commodity.
TL;DR: In the 44 complexes tested including enzyme-inhibitor, antibody-antigen and other complexes, native-like structures were all found, of which 30 were ranked in the top 20 and has the potential to predict protein-protein recognition.
Abstract: An efficient 'soft docking' algorithm is described to assist the prediction of protein-protein association using three-dimensional structures of molecules. The basic tools are the 'simplified protein' model and the docking algorithm of Wodak and Janin. The side chain flexibility of Arg, Lys, Asp, Glu and Met residues at the protein surface is taken into account. The complex type-dependent filtering technique on the basis of the geometric matching, hydrophobicity and electrostatic complementarity is used to select candidate binding modes. Subsequently, we calculate a scoring function which includes electrostatic and desolvation energy terms. In the 44 complexes tested including enzyme-inhibitor, antibody-antigen and other complexes, native-like structures were all found, of which 30 were ranked in the top 20. Thus, our soft docking algorithm has the potential to predict protein-protein recognition.
TL;DR: In this article, a fuzzy risk assessment method was proposed for a petroleum-contaminated site, which consists of three parts: (i) calculation of fuzzy steadystate contaminant concentrations in the aquifer based on an analytical solute transport model, (ii) possibilistic analysis of fuzzy criteria for different risk levels, and (iii) environmental risk assessment based on the Euclidean method.
Abstract: Subsurface contamination at petroleum-contaminated sites is posing a serious threat to the environment and the public and is acquiring more and more attention by governments and industries. This paper proposed a fuzzy risk assessment method and its application to a petroleum-contaminated site. The method consists of three parts: (i) calculation of fuzzy steady-state contaminant concentrations in the aquifer based on an analytical solute transport model, (ii) possibilistic analysis of fuzzy criteria for different risk levels, and (iii) environmental risk assessment based on the Euclidean method. The method can effectively reflect fuzzy natures of environmental quality at a site and evaluation criteria for different risk levels. Results of an illustrative case study indicate that environmental risks at a petroleum-contaminated site can be effectively evaluated through the developed methodology. The assessment results are useful for the related site remediation and management decision.
02 Nov 2003
TL;DR: A new application of rough set to ECG recognition is presented and the recognition rules for characteristic points in ECG are reduced by using rough set theory and used as restriction conditions of eigenvalue determination arithmetic which is presented in this paper and employed in recognizing characteristic pointsIn ECG.
Abstract: When recognizing and analyzing wave signals in electrocardiogram (ECG) automatically, present methods have some limitation and do not meet physicians' expectations. A new application of rough set to ECG recognition is presented. Firstly the recognition rules for characteristic points in ECG are reduced by using rough set theory. Then the reduced rules are used as restriction conditions of eigenvalue determination arithmetic which is presented in this paper and employed in recognizing characteristic points in ECG. There are some discussions about correlative arithmetic such as sizer method, difference method and how to choose difference parameters. Also in this paper, an example of this new application is discussed. We adopt MIT-BIH data to verify R wave recognition and the detection rate is proved higher than the one of routine recognition method.
TL;DR: This study suggests that the application of stress on the intestinal tissue will change the angle and content of collagen fiber, and the method of calculating ratios of different pixel values to estimate collagen fiber angle was practical and reliable.
Abstract: Collagen fiber angle in the submucosa of small intestine and its application in gastroenterology
01 Jan 2003
TL;DR: In this paper, a model of parametrically excited two-degree-of-freedom nonlinear system with the quadratic and cubic nonlinearities is established to explore the periodic and quasiperiodic motions as well as the bifurcations and chaotic dynamics of the system.
Abstract: In this two-part paper, we investigate nonlinear dynamics in the rotor-active magnetic bearings (AMB) system with 8-pole legs and the time-varying stiffness. The model of parametrically excited two-degree-of-freedom nonlinear system with the quadratic and cubic nonlinearities is established to explore the periodic and quasiperiodic motions as well as the bifurcations and chaotic dynamics of the system. The method of multiple scales is used to obtain the averaged equations in the case of primary parameter resonance and 1/2 subharmonic resonance. In Part I of the companion paper, numerical approach is applied to the averaged equations to find the periodic, quasiperiodic solutions and local bifurcations. It is found that there exist 2-period, 3-period, 4-period, 5-period, multi-period and quasiperiodic solutions in the rotor-AMB system with 8-pole legs and the time-varying stiffness. The catastrophic phenomena for the amplitude of nonlinear oscillations are first observed in the rotor-AMB system with 8-pole legs and the time-varying stiffness. The procedures of motion from the transient state chaotic motion to the steady state periodic and quasiperiodic motions are also found. The results obtained here show that there exists the ability of autocontrolling transient state chaos to the steady state periodic and quasiperiodic motions in the rotor-AMB system with 8-pole legs and the time-varying stiffness.Copyright © 2003 by ASME
TL;DR: In this paper, the imminent prediction on a group of strong earthquakes that occurred in Xinjiang, China in April 1997 is introduced in detail, based on comprehensive analyses on the results obtained by multiple innovative methods including measurements of crustal stress, observation of infrasonic wave in an ultra low frequency range, and recording of abnormal behavior of certain animals.
Abstract: . The imminent prediction on a group of strong earthquakes that occurred in Xinjiang, China in April 1997 is introduced in detail. The prediction was made on the basis of comprehensive analyses on the results obtained by multiple innovative methods including measurements of crustal stress, observation of infrasonic wave in an ultra low frequency range, and recording of abnormal behavior of certain animals. Other successful examples of prediction are also enumerated. The statistics shows that above 40% of 20 total predictions jointly presented by J. Z. Li, Z. Q. Ren and others since 1995 can be regarded as effective. With the above methods, precursors of almost every strong earthquake around the world that occurred in recent years were recorded in our laboratory. However, the physical mechanisms of the observed precursors are yet impossible to explain at this stage.
13 Oct 2003
TL;DR: The algorithm of attribute reduction, which is based on the combination of rough set theory with the boosting algorithm, is applied to the linear model of market value functions.
Abstract: The linear model of market value functions is a new method for direct marketing. Just like other methods in direct marketing, attribute reduction is very important to deal with large databases. We apply the algorithm of attribute reduction, which is based on the combination of rough set theory with the boosting algorithm, to the linear model of market value functions. Experimental results compared with the ELSA/ANN model show that the proposed algorithms can be used effectively in the linear model of market value functions.
TL;DR: The soft docking algorithm is described, which produced models where more than half of the antigen residues forming the epitope were correctly predicted, albeit with a wrong VHH domain orientation, and is a promising tool for predicting antibody‐antigen recognition.
Abstract: An efficient soft docking algorithm is described for predicting the mode of binding between an antibody and its antigen based on the three-dimensional structures of the molecules. The basic tools are the "simplified protein" model and the docking algorithm of Wodak and Janin. The side-chain flexibility of Arg, Lys, Asp, Glu, and Met residues on the protein surface is taken into account. A combined filtering technique is used to select candidate binding modes. After energy minimization, we calculate a scoring function, which includes electrostatic and desolvation energy terms. This procedure was applied to targets 04, 05, and 06 of CAPRI, which are complexes of three different camelid antibody VHH variable domains with pig alpha-amylase. For target 06, two native-like structures with a root-mean-square deviation < 4.0 A relative to the X-ray structure were found within the five top ranking structures. For targets 04 and 05, our procedure produced models where more than half of the antigen residues forming the epitope were correctly predicted, albeit with a wrong VHH domain orientation. Thus, our soft docking algorithm is a promising tool for predicting antibody-antigen recognition.
Journal Article•
TL;DR: In this paper, the authors combine the wavelet smoothing method and random weighting method to obtain an approximation of wavelet estimates for parametric components in the semiparametric regression model.
Abstract: Combining the wavelet smoothing method and random weighting method, we obtain that the rates of random weighting approximation of wavelet estimates for parametric components in the semiparametric regression model can attain the accuracy of o(n-1/2) under suitable conditions.
TL;DR: Using Visual C++, a computer-aided software based on Image-Pro Plus (IPP), a software development platform, is developed that has shown its high stability, reliability and ease of utility in 34 clinical studies.
TL;DR: In this paper, the solution polymerization behaviors of organic monomer in cement paste and its effect on cement properties have been studied and the results show that the organic monomers used in the experiment can well polymerize themselves in cement pastes by solution polymerisation effect under common conditions.
13 Oct 2003
TL;DR: A new facial feature extraction method based on linear combination model that locates feature points in facial images precisely and uses the knowledge of prototypic faces to interpret novel faces has been proposed.
Abstract: A new facial feature extraction method is proposed. Based on linear combination model, the method locates feature points in facial images precisely. The model uses the knowledge of prototypic faces to interpret novel faces. To get the knowledge, the prototypes are labeled manually on the feature points. Generally, the construction of the linear combination model depends on pixel-wise alignments of prototypes, and the alignments are computed by an optical flow algorithm or bootstrapping algorithm which is a full-scale optimization and not includes local information such as facial feature points. To combine local facial feature with the linear combination model, a restrained optical flow algorithm is proposed to compute the pixel-wise alignments. With the information of labeled feature points, the model matches the input facial images and extracts the feature points automatically. Implementing the feature extraction method on the MPI face database, the experimental results show that the method has good performance.
15 Dec 2003
TL;DR: A semantic clustering learning technique is proposed, which collects the relevance feedback image retrieval transaction and uses hypergraph to represent images correlation ship, then obtains the semantic clusters by hypergraph partitioning.
Abstract: Semantic clustering is an important and challenging task for content-based image database management. This paper proposes a semantic clustering learning technique, which collects the relevance feedback image retrieval transaction and uses hypergraph to represent images correlation ship, then obtains the semantic clusters by hypergraph partitioning. Experiments show that it is efficient and simple.
TL;DR: In this paper, a mode-locked diode-end-pumped Nd:YAG laser with a semiconductor saturable absorber mirror (SESAM) achieved a 10 ps pulse duration at 150 MHz repetition rate.
Abstract: We report the experimental results of a mode-locked diode-end-pumped Nd:YAG laser with a semiconductor saturable absorber mirror (SESAM) from which we achieved a 10 ps pulse duration at 150 MHz repetition rate. The SESAM was grown by metal organic chemical vapour deposition at low temperature. The recovery time was measured to be 0.5 ps, indicating the potential pulse compression to sub-picoseconds.
TL;DR: In this paper, an inverse design problem of a general eigenvalue of a dynamic system where the elements of the rigidity and mass matrices are linear with respect to a design vector b is studied.
Abstract: This paper studies an inverse design problem of a general eigenvalue of a dynamic system where the elements of the rigidity and mass matrices are linear with respect to a design vector b. The coefficients of spring and mass of a lumped parameters structure, the length and width, the radius, etc play the role of design parameters. For some specified eigenvalues and eigenvectors, the design parameter vector can be obtained and the rigidity and mass matrices of an initially designed structure can be reconstructed by solving linear algebra equations. The theory and method can not only be used for an in-line system, but it can also be used for an inverse vibration design of a complex structure.