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15 December 2005, Volume 26 Issue 12 Previous Issue    Next Issue
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Application of improved genetic algorithm in optimization design He, Da-Kuo (1); Wang, Fu-Li (1); Jia, Ming-Xing (1) 2005, 26 (12):  1126-1126.  DOI: - Abstract ( 301 )   HTML   PDF (182KB) ( 983 )   An improved genetic algorithm is proposed according to lots of nonlinear programming problems found in actual mechanical design optimization. Based on the analyses of simplex search and arithmetic crossover and combining both together, an improved crossover operator is presented to improve the local searching capability of genetic algorithm and lead gradually the population to the extreme point so as to implement the rapid searching. At the same time, to lead infeasible individuals to approach the feasible region so as to improve their feasibilities for the better, the penalty and repair strategies are associated with each other to form a repair operator for repairing infeasible individuals, accelerating the speed of the individuals to approach the feasible region and improving the searching efficiency and the capability in solving the nonlinear constraint. As a whole, the performance of the algorithm is therefore improved. The validity of the algorithm proposed is verified by actual applications to nonlinear programming problems. References | Related Articles | Metrics

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Study on loss-free heavy current switching power supply based on DSP Wang, An-Na (1); Zhang, Hua-Guang (1); Zhang, Shi (1) 2005, 26 (12):  1127-1130.  DOI: - Abstract ( 223 )   HTML   PDF (167KB) ( 528 )   Proposes a topological structure of loss-free heavy current switching power supply based on DSP. For such power supply the input circuit is composed of a series capacitor-switch array and output circuit is composed of a parallel capacitor-switch array. DSP which has rapid run speed and high calculating precision is used as controller, the DSP outputs controllable pulse for on-off control of switch arrays as to change correspondingly the power supply output. Thus state averaging method is used to analyze the charging and discharging processes of the switching power supply. A simulation experiment was carried out to verify the regulation ability of the switching power supply which is featured with regulatable current output. Furthermore, the switching power supply has characteristics of low harmonic, small size, and low power loss. References | Related Articles | Metrics

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Edge detection approach combining canny and wavelet transform Wang, Rong (1); Gao, Li-Qun (1); Chai, Yu-Hua (1); Tian, Lei (3) 2005, 26 (12):  1131-1133.  DOI: - Abstract ( 385 )   HTML   PDF (393KB) ( 1566 )   An edge detection approach combining Canny with wavelet transform is proposed. The source image is decomposed by wavelet and, on the different decomposition levels, the edges of low-frequency sub-images are detected using Canny operator, while the edges of high-frequency sub-images are detected using wavelet transform method. Then, the two edge images are fused into one complying with relevant rules to obtain an integrated and clear edge image. This edge detection method combines the advantages of both wavelet transform and Canny methods together to fuse the two edge information obtained by different methods, thus suppressing effectively the noises with the consecutive and clear edges kept up. Experimental results showed that the approach is superior to either Canny method or wavelet transform method used alone. References | Related Articles | Metrics

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PSO-based water consumption determination for secondary cooling zone during continuous casting Wu, Rong-Yang (1); Wu, Guo-Hua (2); Xie, Zhi (1); Liu, Yu-Gui (3) 2005, 26 (12):  1134-1137.  DOI: - Abstract ( 253 )   HTML   PDF (959KB) ( 781 )   To determine the water consumption in the secondary cooling zone during continuous casting, which will affect the internal quality of CC billets, a new approach is proposed to it on the basis of particle swarm optimizer (PSO). A mathematical model of solidification process is thus developed according to the principle of solidification with volume controlled, and the model is verified by measuring billet shell thickness through nail shooting and sulfur printing. Then, the flattening temperature, reheating temperature and its rise/drop limits are taken as objectives in the artificial intelligent PSO to optimize the water consumption in the secondary cooling zone during continuous casting. Applying the model to the steel Q235, the results showed that the core crack is improved to Grade 0.5 from 1.5 with porosity rate reduced by 7.2% and cracks reduced by 3.6%. It shows the effectiveness of the model. References | Related Articles | Metrics

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Method to identify risk probability of virtual enterprise Huang, Min (1); Xu, Fei (1); Wang, Xing-Wei (1) 2005, 26 (12):  1138-1140.  DOI: - Abstract ( 247 )   HTML   PDF (131KB) ( 533 )   According to the uncertain characteristics of information in virtual enterprise, the Bayesian network is used to identify its risk probability. Discussing the way to construct and analyze the Bayesian network, the dependency relationship of various information variables of such an enterprise is described with Bayesian network, so as to identify the different risk probabilities. Simulation results suggested that Bayesian network could effectively describe the dependency relationship of the uncertain information variables of a virtual enterprise, i.e., an effective method to identify risk probability. References | Related Articles | Metrics

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Fast algorithm for 2-D DOA estimation Liu, Fu-Lai (1); Bai, Zhan-Li (2); Wang, Jin-Kuan (1); Yu, Ge (1) 2005, 26 (12):  1141-1144.  DOI: - Abstract ( 287 )   HTML   PDF (177KB) ( 838 )   Proposes a fast algorithm for two-dimensional (2-D) direction-of-arrival (DOA) estimation of multipath narrow-band sources impinging on the far field of a twin parallel uniform linear array (ULA), analyzing the features and performance of the 2-D DOA estimation algorithms in wireless network communication environment. Compared with the previous work, the proposed algorithm requires a lower computational complexity because the relevant eigenvalue decomposition needed is just for smaller size matrices, and it is available to get the incident beams to which the different azimuth or elevation angles are close with each other. It utilizes the eigenvalues to estimate 2-D DOAs and their corresponding eigenvectors to solve the pairing problem of the estimated 2-D DOAs. Simulation results showed the effectiveness of the proposed algorithm, such as smaller estimation error and higher robustness to SNR. References | Related Articles | Metrics

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Fusion of Bayesian networks to forecast oil reservoir distribution Xu, Ye (1); Zhao, Hai (1); Su, Wei-Ji (1); Zhang, Wen-Bo (1) 2005, 26 (12):  1145-1148.  DOI: - Abstract ( 238 )   HTML   PDF (157KB) ( 668 )   A Bayesian fusion model is put foreword with a corresponding algorithm designed to forecast the oil reservoir distribution A clustering analysis algorithm, k-mean algorithm, is expanded and optimized to avoid errors due to data classifying in various professional fields, such as geology, logging and shaft drilling. Eventually, a conclusion is drawn the way the fusion center processes the output from Bayesian network as objective probability knowledge in combination with the subjective knowledge provided by experts in different fields. Experimental results showed that the method has successfully solved many problems which the conventional single-neuron network-modeling method was hard to resolve, such as difficult to design, long training cycles, low forecasting speed and inexact classifying results, thus meeting the requirements for such a forecast. References | Related Articles | Metrics

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Influence of induced current on magnetic flux density in soft-contact mold Deng, An-Yuan (1); Wang, En-Gang (1); He, Ji-Cheng (1) 2005, 26 (12):  1149-1152.  DOI: - Abstract ( 198 )   HTML   PDF (180KB) ( 640 )   FEM is used to simulate numerically the magnetic flux density and induced current distribution in a rectangular soft-contact electromagnetic continuous casting (EMCC) mold. Investigates the influences of such parameters as power frequency, electric conductivity of mold material and mold construction on the magnetic flux density and induced current, as well as the effect of induced current on the magnetic flux density in the mold. The simulative results show that the magnetic flux density due to induced current formed on mold segment affects greatly the magnetic flux density in mold, and utilizing reasonably the induced current can enhance the magnetic flux density in mold so as to save energy. For slit mold, within a certain frequency band, the magnetic flux density due to induced current can enhance the magnetic flux density in mold, but, if the frequency is beyond the band, the enhancement is not obvious. In the high-frequency EMCC process, the magnetic flux density in mold mainly comes out of the penetration of magnetic flux density due to the induction of outer coil, while in case of low frequency how to utilize fully the induced or secondary field to enhance the magnetic field in mold should be taken into account. References | Related Articles | Metrics

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Constant permeability of amorphous Fe78Si9B13 alloy Zhi, Qi-Zheng (1); Chen, Wen-Zhi (2); Jiang, Zhen-Chun (1); He, Kai-Yuan (1) 2005, 26 (12):  1153-1156.  DOI: - Abstract ( 248 )   HTML   PDF (820KB) ( 746 )   The effect of normal annealing process on the magnetic properties of amorphous Fe78Si9B13 alloy was investigated experimentally. It was found that when a moderate amount of crystalline α-Fe(Si) phase precipitates, the induced magnetic anisotropy forms, of which the easy magnetization direction is perpendicular to the alloy ribbon surface. A good constant permeability is provided for the alloy if annealed at 470°C for 120 min or 480°C for 60 min. According to the relation of residual induction ratio Br/B800 to annealing temperature/time, the influence of crystallization behavior in the alloy's surface layer and matrix on transversely induced magnetic anisotropy resulting from magnetoelastic coupling was also discussed. References | Related Articles | Metrics

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Study on Fe-C-MoS2/CuSn alloy-based composites Ru, Hong-Qiang (1); He, Feng-Ming (1); Huo, Di (1); Jia, Ji-Xiang (1) 2005, 26 (12):  1157-1160.  DOI: - Abstract ( 235 )   HTML   PDF (395KB) ( 606 )   The Fe-C-MoS2/CuSn alloy-based antifriction composites were prepared through powder metallurgy, of which the microstructure and mechanical properties were studied. The results showed that the CuSn alloy provides good electric conductivity for the composites, and its strength is higher than that of the sintered materials of the same alloying elements. The wettabilities of CuSn alloy and Fe are so high that accelerate the alloying process of sintering so as to improve greatly the strength, hardness and notch toughness. The thermal expansion coefficient of free carbon distributed in matrix is higher than that of the matrix itself and plays a role of antifriction in the composites. Meanwhile, the MoS2 homogenously distributed in matrix also plays evidently the role of antifriction at high temperature. If the mass fraction of Fe is up to 15%, the toughness is 20.6 J/cm2, tensile strength 163.2 MPa and HB hardness 53.8, i.e., properties of this composites have been up to even exceeded the standard TB/T1842.1-2002 for the slides made via powder metallurgy for electric locomotives. The composites thus become a new material for the pantograph slides of high-speed locomotives. References | Related Articles | Metrics

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Simulation of temperature field during hot plate rolling Zhou, Xiao-Guang (1); Wu, Di (1); Zhao, Zhong (1); Wang, Ping-Ji (2) 2005, 26 (12):  1161-1163.  DOI: - Abstract ( 263 )   HTML   PDF (286KB) ( 998 )   It is difficult to determine precisely the temperature field in plate rolling process to which the error of calculated result is too great with tiresome calculating procedure if using conventional temperature models. So, based on the heat transfer theory, a thermal balance equation as model is developed using the implicit difference method to simulate the temperature variation of plate core/surface in hot rolling and cooling processes for plate production. Some conclusions are thus reached: (1) the plate surface temperature decreases sharply during rolling, but it tends to increase in the interval between intermittent rolling passes. During cooling, the plate surface temperature decreases quickly. (2) The calculated plate surface temperature is in agreement with that measured and, therefore, the model is available to simulate the temperature variation in plate rolling process. References | Related Articles | Metrics

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Investigation on formability and nonaxisymmetric distortions during hole-flanging of TC2M1.5 titanium alloy sheet Zhang, Ling-Yun (1); Cui, Jian-Zhong (1) 2005, 26 (12):  1164-1167.  DOI: - Abstract ( 276 )   HTML   PDF (221KB) ( 765 )   To make sure of the effect of anisotropy on the shape/size precision of workpiece, a series of hole-flanging experiments were carried out at room temperature and 600°C, with 1.5 mm-thick TC2M titanium alloy sheet as specimens on which pre-drilled holes were provided at the center. It was found that there are some nonaxisymmetric distortions such as peripheral flange warpage, elliptical opening shape, uneven lip surface of the finished hole and ununiformly distributed wall thickness after unloading in addition to the normal rupture at lip edge when the initial hole diameter is smaller than the minimum size. The flanging process at high temperature can improve effectively formability, get rid of peripheral warpage and elliptical opening, but the lip surface and wall thickness can not be evened yet. The ultimate hole-flanging coefficient is given in two different states, while the nonaxisymmetric distortions are quantitatively described and analyzed. References | Related Articles | Metrics

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Analysis of eco-efficiency of steel industry Dai, Tie-Jun (1); Lu, Zhong-Wu (1) 2005, 26 (12):  1168-1173.  DOI: - Abstract ( 453 )   HTML   PDF (301KB) ( 1324 )   Defining the product from the angle of industrial ecology, the three indices of eco-efficiency are given, i.e., resources efficiency, energy efficiency and environment efficiency, to analyze the eco-efficiency of steel industry. Taking the data of a steel enterprise as example, an input/output balance sheet was worked out by way of industrial metabolism to make sure of the sorts and amounts of resources, energy, products, wastes and pollutants and analyze the eco-efficiency of the steel enterprise. Discusses the influence of symbiotic relationship among the wastes/pollutants utilized mutually by different enterprises on the three efficiencies mentioned above. It was found that the formation of such a symbiotic relationship is an important way to solve the increasingly serious problems of resources, energy and environment in China's steel industry. References | Related Articles | Metrics

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Assessment based on nonlinear parameters of EEG α waves for human-body fatigues Wang, Li (1); Yu, Tao (1); Wen, Bang-Chun (1) 2005, 26 (12):  1174-1177.  DOI: - Abstract ( 310 )   HTML   PDF (265KB) ( 1677 )   Based on the three calculated nonlinear parameters of the waves, i.e., maximum Lyapunov exponents, complexity and approximate entropy, which are extracted from the original electroencephalograph (EEG) signals with wavelet transform technique, a comprehensive criterion is proposed to assess the human-body fatigue levels. The three nonlinear parameters are available to quantitatively reflect human's physiological activities and, further, evaluate the fatigue level of human body. Computing and analyzing statistically the existing EEG data, a comprehensive assessment criterion is set up for fatigue levels in terms of the nonlinear parameters as above. For the known 18 sets of different EEG signal data measured, the assessment results are obtained correspondingly. Compare with actualities, the identification accuracy of fatigue got in this way tends to 100%. However, the accuracy to differ being a bit tired from medium tiredness or being extremely fatigued is relatively lower than expected. References | Related Articles | Metrics

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Calculating natural frequency characteristics by integrated transfer matrix of complete set of rotary machines Li, Yong-Qiang (1); Zhu, Liang (1); Liu, Yu (2); Liu, Jie (2) 2005, 26 (12):  1178-1180.  DOI: - Abstract ( 308 )   HTML   PDF (158KB) ( 897 )   Sub-structure transfer matrix is often used to analyze the natural characteristics of multi-rotor systems. But, it is not easy to develop a versatile program for the transfer matrix because of its complexity in calculation and diversity of structures. A calculation procedure is thus given to integrate all the state vectors of individual rotors together so as to form a systematical state vector to link all rotors together through coupling elements. In this way no unknown internal force and displacement will be introduced in and no balance equations or conditions to coordinate different deformations are required at division points. Derives the transfer matrix of isotropic coupling element with some examples given to verify it, and results showed that the integrated transfer matrix is higher in computational accuracy and available to keep such advantages of conventional transfer matrix as easy to program, small workload and high operating speed. Thus, it provides an effective way to develop a versatile program. References | Related Articles | Metrics

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Position/force control based on fuzzy prediction in unknown environment Wang, Lei (1); Liu, Hong-Yi (1); Wang, Fei (1) 2005, 26 (12):  1181-1184.  DOI: - Abstract ( 281 )   HTML   PDF (255KB) ( 781 )   A fuzzy prediction algorithm arising from conventional hybrid position/force control model is developed to deal with a force-controlled execution of compliant robot tasks in an unknown environment. According to the known contacting path of the manipulator's end effector and its motional direction, the algorithm makes use of the three prediction factors (satisfiability, curvature adaptability and reference proportion) to predict and readjust the desired trajectory given in hybrid position/force control model when sampling in future. The last prediction shall be re-evaluated first once a prediction starts and, at the same time, the environmental change in curvature and stiffness should be taken into account. The algorithm is also available to be applied to impedance control model. The simulation results verify that the proposed fuzzy prediction will result in better force control in different control models and has high adaptability to unknown environment in changing. References | Related Articles | Metrics

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Normal and inverse pose solutions to 3-RPS parallel robot based on ADAMS Wang, Dan (1); Guo, Hui (1); Sun, Zhi-Li (1) 2005, 26 (12):  1185-1187.  DOI: - Abstract ( 317 )   HTML   PDF (194KB) ( 1265 )   Based on ADAMS software, a way to get both normal and inverse pose solutions to 3-RPS parallel robot was put forward. With the pose of manipulator given first, the time-dependent curves of driving link can be obtained through simulation. Then, the curves are processed by a postprocessing module of ADAMS to get the spline function of driving link displacement, thus getting the inverse solutions. Adding the inverse solutions as a drive to the driving link with a simulation conducted, the pose of manipulator can be gotten. The normal solution is got the way the displacement curve of manipulator, measured via simulation, is processed by the postprocessing module, so as to determine the spline function of manipulator's pose hence the normal solution. In such a way no big amount of workload is required in programming and computation, featured with fast, convenient and exact, and both normal solution and inverse solution can be used in practice. References | Related Articles | Metrics

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CIMS-oriented information tracking/monitoring system for workshop production process Sui, Tian-Zhong (1); Cui, Hong-Wen (2); Zhao, Hong-Yu (3) 2005, 26 (12):  1188-1191.  DOI: - Abstract ( 322 )   HTML   PDF (219KB) ( 1156 )   Analyzes the operation process flow of the management that track the whole production process in workshop, and takes the development of manufacturing-process management and resource optimizing configuration system in an enterprise as the background. Thus, the functional and information models are established to track/monitor the whole production process in workshop and, based on it, a production-oriented process tracking/monitoring system is developed for manufacturing workshop in QMS environment utilizing COM+ and distributed Web technologies. It has been applied in actual production. At the same time, the integration of this system with other CIMS subsystems has been realized to upgrade the running/managing level as a whole in manufacturing workshops. References | Related Articles | Metrics

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- - 2005, 26 (12):  1192-1195.  DOI: - Abstract ( 254 )   HTML   PDF (163KB) ( 542 )   - References | Related Articles | Metrics

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- - 2005, 26 (12):  1196-1199.  DOI: - Abstract ( 241 )   HTML   PDF (183KB) ( 1283 )   - References | Related Articles | Metrics

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Preparation of Co3O4/Fe2O3 core-shell particles and their optic properties Zhang, Xia (1); Zhao, Yan (2); Zhang, Cai-Bei (1); Li, Yan-Hua (3) 2005, 26 (12):  1200-1203.  DOI: - Abstract ( 194 )   HTML   PDF (357KB) ( 810 )   The amorphous Co(OH)2 obtained from the hydrolysis of CoCl2 under the catalysis of ammoniac base could be deposited on the surface of monodispersed pseudo-spherical α-Fe2O3 nanoparticles to form core-shell particles. After the heat treatment at 500°C, the structure of shell layer crystallized into cubic Co3O4 with a thickness about 6 nm. Different ammoniac bases and their concentrations would affect the structure of the core-shell particles, and it became homogeneous if catalyzed in 1 mol · L-1 urea solution. TEM and XRD were used to analyze the structure of the core-shell particles. Compared to pure α-Fe2O3 nanoparticles, the UV-Vis spectrum of the core-shell particles showed that their optic properties were changed under photoexcitation and a new absorption peak with maximum absorbance appeared in visible region. References | Related Articles | Metrics

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Synthesis of the inclusion complex 1-MCP/β-CD and its spectral characteristics He, Yi (1); Sun, Ting (1); Yang, Gui-Qiu (1); Liu, Jia-Nu (1) 2005, 26 (12):  1204-1206.  DOI: - Abstract ( 293 )   HTML   PDF (104KB) ( 965 )   The low stability of 1-Methylclopropene (1-MCP) as an receptor inhibitor for ethylene was investigated for improvement. An inclusion complex, 1-MCP synthesized with β-Cyclodextrin (β-CD), was therefore prepared through solubilization utilizing the unique special structure of β-CD, i.e., internally hydrophobic and externally hydrophilic. In the inclusion complex, the β-CD can play the role in improving the stability with the penetration guest molecule. The inclusion complex was characterized by X-ray powder diffraction (X-RPD), differential thermal analyzer (DTA) and UV/IR absorption spectrometry. The difference between β-CD and the inclusion complex was found by spectral comparison and analysis, which verify the formation of the inclusion complex. References | Related Articles | Metrics