Showing papers by "Taiyuan University of Technology published in 2000"

Photoelectrocatalytic Oxidation of Rose Bengal in Aqueous Solution Using a Ti/TiO2 Mesh Electrode

Abstract: To further improve the photooxidation techniques for water and wastewater purification, a new type of photoelectrode, Ti/TiO2 mesh electrode, was successfully prepared by anodizing Ti mesh in 0.5 M H2SO4 solution. The structural and surface morphology of the Ti/TiO2 electrode was examined by Raman spectroscopy and scanning electronic microscopy (SEM), respectively. The examination results indicated that its structure and properties were affected by its growth rate in the anodization process, and anatase TiO2 was dominant in its composition. The photocatalytic (PC) oxidation and photoelectrocatalytic (PEC) oxidation of rose Bengal (RB) in aqueous solution using the Ti/TiO2 electrode were investigated and compared. The experimental results demonstrated that the PEC oxidation by applying an electrical bias between the Ti/TiO2 electrode and Pt electrode could significantly enhance the degradation rate of RB compared with the PC oxidation. It was found that the best performance of PEC oxidation was achieved by...

Study on the structure and tribological properties of CrN coating by IBED

Abstract: CrN coatings were synthesized with different levels of bombarding energy by nitrogen ions with very low N ion/Cr atom arrival ratios. The structures and compositions of these coatings were investigated by XRD, XPS and AES. The tribological properties of the coatings on AISI 52 100 steel were evaluated by ball-on-disc tests. Results indicate that the fraction of the CrN phase increases with increasing bombarding energy from 4 to 8 to 12 keV, and reaches a predominant state. For the 4 keV coating, the Cr/N ratio was >1, which indicates that Cr is involved in the coating layer. The 8 and 12 keV coatings were free of Cr phase. However, the optimum N ion/Cr atom ratio for the coating is far from the stoichiometry of 1:1 Cr/N. The tribological properties of CrN coatings with different processing parameters show that the wear mechanisms of coating/substrate systems are micro-ploughing and spalling. The films processed at a low energy level and with a low N ion/C atom ratio in this study show better tribological properties and higher fracture toughness.

Thermoelastic free vibration of clampe circular plate

Abstract: An analysis was given for the free vibration of clamped circular plate when temperature and stress fields were coupled. A nonlinear differential equation about time was obtained by using Galerkin's method. The numerical results of vibration amplitude vs time were compared with the uncoupled case. It is found that if the given initial displacement is small, the effect of thermoelastical coupling will make the natural frequency increase; if the given initial displacement is large, it will be the opposite case. Effects of some different vibration factors are also discussed.

A study of nickel-based corrosion resisting alloy layer obtained by double glow plasma surface alloying technique

Abstract: In this paper, Ni–Cr–Mo–Nb multi-element surface alloying has been investigated on a substrate of three kinds of industrial steels (industrial pure iron, low carbon steel and 304 stainless steel) by means of the double glow plasma surface alloying technique The results showed that highly alloyed nickel-based surface alloying layers were formed on the surface of the three kinds of steels The alloying layer was uniform, continuous and compact The alloying layers consisted of a γ phase or γ matrix with several precipitates (P or Laves phase, and NbC carbide, etc) A method of eliminating these precipitates has also been discussed The corrosion resistance of the nickel-based surface alloying layer was investigated by an electrochemical method in a 35% NaCl and 5% HCl solution, and 200-h exposure tests in a 20% H2SO4 and 20% HCl solution The corrosion resistance of surface alloying layer formed on stainless steel substrate was better than that of the nickel-based alloy Inconel 625 and 304 stainless steel The experimental results indicated that this is an effective way to obtain a high quality corrosion resisting surface alloying layer on the surfaces of steels using the double glow plasma surface alloying technique

Application of the mind-evolution-based machine learning in mixture-ratio calculation of raw materials cement

Abstract: Mind-evolution-based machine learning (MEBML) is an evolutionary computing algorithm. It inherits "colony" and "evolution" of evolutionism. MEBML adopts "similartaxis" and "dissimilation" operators, which possess the more rapid convergence and the higher calculation accuracy. Aiming at a difficult problem for the accurate mixture ratio of raw materials of cement processing, MEBML is proposed, which calculates the mixture ratio of raw materials of cement and overcomes the defects of general calculation methods. The simulation example is given to show that this algorithm not only has a rapid convergence rate and high calculation accuracy, but also has not the prematurity problem of a genetic algorithm. This algorithm can be applied to any mixture ratio calculation of other materials.

Mind-evolution-based machine learning and applications

Abstract: This paper describes the foundation of proposing MEBML (mind-evolution-based machine learning) that was recently presented. Then the paper analyses the performance mechanism of MEBML which is different from GA (genetic algorithm), and its characteristics. With its own distinctive mechanism MEBML improved the efficiency and convergence rate greatly compared with GA. The paper also summarizes the recent development of researches on MEBML, which includes several different strategies of similarity and dissimilarity, the proof of convergence of MEBML and its applications. In addition the authors discuss the future work of MEBML.

Age-hardening of surface age high speed steel on high carbon steel after plasma decarbonizing

Abstract: Steel T8 treated by plasma surface decarburizing is alloyed by the Xu-Tec process with Co, W and Mo. An alloying layer of FeCoWMo with low carbon content is formed on the surface of the high carbon steel, which is an advanced gradient composite. The specimens after alloying are treated by the solution and aging treatments. The characteristics of age-hardening of the alloying layer are studied. The surface alloying layer of FeCoWMo possesses a very strong ability of age-hardening. The hardness of the surface layer is increased from 200 to 1070 Hv after the solution treatment at 1190°C and aging 30 min at 400°C. The experimental results show that the surface aged high speed steel possesses not only high surface hardness, but also enough strength of the bulk material, so it will be used widely in the fields of tool, mould and others where high wear-resistance is required.

Mind-evolution-based machine learning: an efficient approach of evolution computation

Abstract: This paper analyses mind-evolution-based machine learning (MEBML) that has been proposed recently. The paper first discusses the practical problems in the implement of MEBML in numerical optimization. Then the paper gives the criterion used to judge whether a group is mature, also the paper proposes a adaptive method to adjust the parameters in similar taxis. The results of the experiment of numerical optimization are given. The experiment shows that the global convergence rate and computation efficiency are both improved above 20% compared with standard genetic algorithm. The improvement in convergence rate and efficiency is due to the distinctive structure of MEBML and the introduction of similar taxis and dissimilation.

Synthesis of aluminum nitride films by activated reactive ion plating with a cathodic arc source

Abstract: A new type of method, which synthesized aluminum nitride (AlN) films by activated reactive ion plating with a cathodic arc source, was introduced. Using aluminum and nitrogen gas as source materials, the aluminum nitride films were deposited on Si(100), Mo and stainless steel substrates, and the deposition rate was varied from 4.7 to 20.2 nm/s. The structure and morphology of the synthesized films were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared reflection absorption spectroscopy (IRAS). The morphology of the films was cauliflower. A transition zone was detected between the film and the substrate.

Preparation of Y/MCM-41 composite materials

Abstract: A composite material (denoted as Y/MCM-41) composed of a core of zeolite Y particle and a thin layer of MCM-41 have been prepared by the crystallization of the reaction mixture of MCM-41 and zeolite Y particles. The Y/MCM-41 particle size increases with the increase of the SiO2/Al2O3 ratio of MCM-41. Introduction of hydroxymethyl fiber into the zeolite Y particle favors the significant increase of its strength, but zeolite p easily formed. The adsorption property of Y/MCM-41 is different from those of zeolite Y and MCM-41. H(Y/MCM-41) as a catalyst is highly selective to C4-C5hydrocarbons and slowly deactivated in the cracking of n-heptane compared to the mechanical mixture particles of HY and HMCM-41 (designated as H(Y+MCM-41)).

Plasma surface alloying of spheroidal graphite iron

Abstract: Spheroidal graphite iron is chosen as a substrate material on which plasma WMo and NiCr surface alloying are carried out by the Xu-Tec process. The experimental results show that WMo surface alloying increases the surface hardness of the cast iron from approximately 200 to 1500 HV while NiCr alloying enhances the surface hardness to 600 HV or above and also the corrosion-resistance of the cast iron. The alloy content and hardness of the alloyed layer manifest a gradually decreasing tendency from surface to the inside of the substrate, an ideal profile which is beneficial to the cohesion of the surface modification layer with the bulk material. The microstructures, alloy contents and surface hardnesses of the alloyed layers are presented. Effects of processing conditions and carbon, silicon content of the specimens on the alloying results are also discussed.

Raman and infrared spectra, conformational stability, normal coordinate analysis andab initio calculations of 3-chloro-1-butene

Abstract: The Raman and infrared spectra (3300–30 cm−1) of gaseous and solid 3-chloro-1-butene, H2C=CHCCl (CH3)H, were recorded. Additionally, the Raman spectrum (3300–30 cm−1) of the liquid was recorded. All three conformers were observed in the fluid phases and the conformer with the hydrogen atom eclipsing the double bond (HE form) was identified as the most predominant. From variable-temperature measurements in liquified xenon, the enthalpy differences between the HE form and the two less stable conformers, i.e. the methyl group eclipsing the double bond (ME form) and the chlorine atom eclipsing the double bond (ClE form), were determined to be 75 ± 8 cm−1 (214 ± 23 cal mol−1) and 197 ± 37 cm−1 (563 ± 106 cal mol−1), respectively. Nearly complete vibrational assignments are proposed for all three conformers, which are consistent with the predicted wavenumbers utilizing the force constants from ab initio MP2/6–31G(d) calculations. Both the infrared intensities and the Raman activities and depolarization values were obtained from the ab initio calculations. Complete equilibrium geometries were determined by ab initio calculations employing the 6–31G(d) and 6–311++G(d,p) basis sets with full electron correlation by the Moller–Plesset (MP2) perturbation method to second order. The structural parameters obtained with the larger basis set are comparable to those obtained from a previously reported electron diffraction study. The results are discussed and the theoretical values are compared with the experimental values when appropriate. Copyright © 2000 John Wiley & Sons, Ltd.

The multi-parameter combination mind-evolutionary-based machine learning and its application

Abstract: Based on mind-evolutionary-based machine learning (MEBML), four conceptions: degree of interaction, individual similartaxis, group similartaxis and dead band space are defined in this paper. Consequently, the multi-parameter combination mind-evolutionary-based machine learning (MPCMEBML) is established. MPCMEBML can solve efficiently the searching problem of the multi-dimension parameter space. In MDPMEML, the whole parameter space is separated and combined into several sub parameter spaces and the global billboard is endowed with the interactive function. Not every single group searches the whole parameter spaces. Information exchange will supplement the insufficient knowledge that not every group can get by itself. The new fuzzy logic controller is constructed by using MPCMEBML. Simulation results show that MPCMEBML is possessed of a strong ability of searching in the multi-dimension parameter space and the new FLC has good performance.

A high-resolution magnetostratigraphy study on the nihewan group at xujiayao

Abstract: A high-resolution paleomagnetism study was made at two parallel sections of Nihewan group at Xujiayao Paleolithic site. More than 10m reversed polarities were found at the middle-low parts of both sections. According to the K-Arages of volcanic beaus near by the sections, it is derived that the reversed polarities should be the Matuyama reversed polarity zone. The Blake reversed excursion reported previously was denied.

The single-neural cascade control system of intelligent switch regulating devices and its application

Abstract: A regulating device which consists of a main regulator, sub-regulator and regulating valve, is proposed. The control device has a structure of double-loop cascade control that can realize intelligent switching. At the same time, a supervisory Hebbian rule based single-neural PSD adaptive controller is designed for the controlled objects with nonlinear parameter loads. Under the condition of configuration using the functional blocks of Bailey Controls' CLC-04 programmable regulator, we controlled the reheated steam temperature of the 670T/H boiler at the 200 MW Shanxi Shentou power plant unit for 78 hours. The results obtained indicate that the single-neural cascade compound control system, which consists of an intelligent switch for the regulating devices, gives good controllability and robustness.

Gray image segmentation on MEBML frame

Abstract: A segmentation technique of gray images is built on the framework of MEBML (mind-evolution-based machine learning). Both gray-level homogeneity and geometric connection of pixels are measured in the method, and it is more sophisticated than ordinary thresholding techniques.

New Paleomagnetic Results about the Age of Ni‐ Hewan Group and Paleolithic Layer At Xujiayao Paleolithic Site

Abstract: The age of the lacustrine Nihewan Group has been a matter of dispute for decades. An initial Early Pleistocene age was extended to Late Pleistocene based on palaeolithic evidence and mammal fossils. The presence of a short reversed polarity zone proposed to represent the Blake geomagnetic excursion (0.117Ma B.P) apparently confirmed this age[1]. We report on a new, high-resolution paleomagnetic record from two parallel sections at Xujiayao revealing a Normal polarity zone at the middle-upper section and an extensive reversed polarity zone within the middle-lower part of the section. K-A ages (0.45±0.08 B.P and 0:38±0:07Ma B.P) of basalt underlying the lacustrine sediments nearby whose horizon can be correlated to the layer with normal polarity at the paleolithic section suggest the normal and reversed polarities should be Brunhes and Matuyama Chron. The Blake reversed excursion was denied. The Nihewan Group at Xujiayao and the paleolithic layers within the lacustrine sediments must hence be much older than Late Pleistocene.

Structural characteristics of boron nitride thin films synthesized by the technique of unequal-potential hollow-cathode effect

Abstract: Boron nitride thin films were synthesized on Si(100) substrates in (5% B 2 H 6 +He)/N 2 /H 2 gas mixtures by the technique of unequal-potential hollow-cathode effect (UPHCE). Because of the electric current magnification function of UPHCE, the reactive gas mixture (N 2 , B 2 H 6 , etc.) was activated and ionized effectively. The structure characteristics of the films were investigated by X-ray diffraction (XRD) and infrared reflection absorption spectroscopy (IRAS). Results show that the phases of BN thin films, which contain cBN phase and hBN phase, are changed with the difference of the flow ratio of reactive gases.

Modeling analysis for the temperature system using rough sets

Abstract: The knowledge reduction algorithm of rough sets (RS) theory is employed to qualitatively analyze the main working condition factors, which influence the model parameters of a superheated steam temperature system in modeling. After reduction, the data that reduced from 19 to 4 clearly shows the relationship between the factors and the parameters. Then, a different classification method was used to classify the decision attributes, and the result shows that different attribute classifications will simplify the problem but not change the property of the problem.

A MEBML-based adaptive fuzzy logic controller

Abstract: In this paper, a new adaptive fuzzy logic controller with online tuning the scaling factor is proposed. By using the information from the fuzzy logic controller and experience rules, the output scaling factor and transforming functions from the fuzzy universal discourse to the basic one in the fuzzy logic controller, are decided. In this way, the controller possesses an adaptive ability. Furthermore, a new evolutionary computing method, called the mind-evolutionary-based machine learning (MEBML), is adopted in this paper. MEBML inherits "colony" and "evolution" of the evolutionism. It jumps the traces of the gene and solves successfully the encoding problem of the genetic algorithm. Simulation illustrates that this new adaptive fizzy controller not only can self-tune the parameters of the controllers online and increase control system qualities, but its algorithm is also simple and easy to be established.

A low cost display, alarm and control circuit for distributed computer monitoring and control system

Abstract: Introduces the method of the low cost display, alarm and control circuit for a distributed computer monitoring and control system. This circuit has the characteristic of making full use of the hardware resource, flexibility and low cost. The method is not only useful for distributed computer monitoring and control system but also can be used for an intelligent instrument to reduce its cost and reduce its volume. The case study on a coalmine distributed computer monitoring and control system shows the high efficiency and low cost of this method.

Anomalous dynamics response of nonlinear elastic bar

Abstract: The dynamics behaviour of tension bar with periodic tension velocity was presented. Melnikov method was used to study the dynamic system. The results show that material nonlinear may result in anomalous dynamics response. The subharmonic bifurcation and chaos may occur in the determined system when the tension velocity exceeds the critical value.

Single neuron self-adaptive PSD control and its application in reheat steam temperature control system

Abstract: A new cascade feedback control system with load feed-forward of reheat steam temperature is proposed in this paper. Single-neuron self-adaptive PSD algorithm controller applied to outer loop and double-degree PID controller is applied to inner loop. The methodologies of design and configuration the implementation was made with single-loop digitizer regulator CLC-04 of Bailey Inc. The simulation and practical results show the satisfactory control results have been achieved.

An analysis on microstructures of alloyed layer by double glow plasma W-Mo alloying process after carburizing

Abstract: The surface high speed steel and its high propeties are obtained by surface alloying with W Mo, carburizing, quenching and tempering. W Mo alloy layer is formed by double glow plasma alloying process. To dissolve the intermetallics which precipitated from the matrix of the layer, a solution heat treatment is conducted. The carburized alloyed layer possesses high density of finery and dispersed alloy carbides for the high concentrations of W, Mo and their affinities with carbon. Microstructures of the carburized alloyed layer are analysised in detail by TEM.