Loading...

Table of Content

    25 February 2010, Volume 38 Issue 2
    Previous Issue    Next Issue
    Chemistry & Chemical Engineering
    Modification of Aluminum Pigments via Encapsulation with Polyacrylate and Silicon Dioxide
    Gao Ai-huan Pi Pi-hui Lu Yang Wen Xiu-fang Cheng Jiang Yang Zhuo-ru
    2010, 38(2):  1-5.  doi:10.3969/j.issn.1000-565X.2010.02.001
    Asbtract ( 759 )   PDF (332KB) ( 1022 )  
    Related Articles | Metrics

    In order to enhance the corrosion resistance and resin consistence of aluminum pigments, SiO2 and polyacrylate were used to encapsulate the pigments by means of the sol-gel method and the in-situ polymerization, respectively. Then, the mechanism of encapsulation was analyzed, and the surface morphology and structure of the encapsulated pigments were characterized by means of FT-IR, XPS and ESEM. Moreover, the influences of encap- sulating conditions on the properties of the coating films containing encapsulated aluminum pigments were investigated. The results show that, with a monomer dosage of 0. 7 g, the aluminum pigments encapsulated at 85 ℃ for 4 - 5 h is of significantly-improved dispersibility and adhesion, which enables the coating film to possess good appearance, high glossiness, and strong acid resistance.

    Effects of Synthesis Conditions on Morphology and Structure of Hollow Mesoporous Silica Microspheres
    Liao Shi-jun Yang Xu Liang Hua-gen Du Li
    2010, 38(2):  6-11.  doi:10.3969/j.issn.1000-565X.2010.02.002
    Asbtract ( 639 )   PDF (358KB) ( 1167 )  
    Related Articles | Metrics

    Hollow silica spheres material（HSSM） with mesoporous wall and a specific surface area up to 951 m2/g were successfully synthesized, with dodecyl amine as the main template and with polyethylene glycol 1000 as the co-template. The effects of such synthesis conditions as temperature, concentration and solvent on the structure and morphology of HSSM were then investigated. The results show that   both the temperature and the solvent obviously influence the morphology and structure of HSSM;   at the optimal volume ratio of water to ethanol, namely 5： 2, hollow microspheres with smooth surface and high structure-ordering degree can be obtained;   a volume ratio higher than 6：1 or lower than 4：3 may result in irregular bulk with low ordering degree or mesoporous material with high ordering degree, respectively;   when the synthesis temperature is lower than the optimal one, namely 30 to 40 ℃, hollow microspheres cannot be obtained, while hollow microspheres may be destroyed when the temperature is higher than the optimal one; and   only when the mixed template concentration increases to 0. 038 mol/L can hollow microspheres-but not solid microspheres-be synthesized.

    Synthesis and Photoelectric Properties of N-Ethylcarbazole-Based Dendrimer
    Zhu Zhi-bo
    2010, 38(2):  12-16.  doi:10.3969/j.issn.1000-565X.2010.02.003
    Asbtract ( 681 )   PDF (317KB) ( 863 )  
    Related Articles | Metrics

    In this paper, first, amorphous N-ethylcarbazole dendrimers were synthesized by means of both bromination （iodination） reaction and Ullmann coupling reaction. Then, the HOMO （ -5. 16eV） and LUMO （ - 1.59eV） energy levels of the product were obtained at a B3LYP/6-31G（d,p） level via the theoretical analysis based on the density functional theory. The calculated results accord well with the experimental ones. Moreover, the photophysical properties of the product were investigated. It was found that the compound had a maximum absorption at 292 nm and a maximum emission at 394 nm. Finally, the electrochemical properties of the compound were analyzed by means of cyclic vohammetry. The results show that reversible dual-oxidation peak with an onset oxidation potential of 0. 74V can be found in the N-ethylcarbazole dendrimers with a two-photon absorption cross section of 13.86×1050cm4·s·（photon） -1.

    Local Heat Transfer Performance of Shell Side of Axial-Flow Shell-and-Tube Heat Exchanger with MPC
    Zeng Wen-liang Deng Xian-he Li Zhi-wu
    2010, 38(2):  17-22.  doi:10.3969/j.issn.1000-565X.2010.02.004
    Asbtract ( 653 )   PDF (387KB) ( 1100 )  
    Related Articles | Metrics

    In this paper, the local heat transfer performance of the shell side of an axial-flow shell-and-tube heat exchanger with multi-parallel-channel inlet/outlet （MPC） was experimentally studied, with or without distributed baffles being set in the inlet region at the shell side. The investigation includes such aspects as （ 1 ） the distribution of local surface Nusseh number （Nu） in the inlet region; （2） the correlation between the local-mean surface Nusseh number and the tube bundle location as well as the Reynolds number （Re） ; （3） the variations of mean Nusseh number and Reynolds number of the inlet region and the heat exchanger; （4） the distribution rule of the local surface Nusselt number of the inlet region at the shell side ; and （5） a reasonable mechanism analysis of the abovementioned statements. The results indicate that distributed baffles effectively improve the fluid flow distribution and enhance the overall heat transfer performance of the shell side of the heat exchange.

    Solubility of Cellulose in ZnCl2 Aqueous Solution and Structure of Regenerated Cellulose
    Xiong Jian Ye Jun Zhao Xing-fei
    2010, 38(2):  23-27.  doi:10.3969/j.issn.1000-565X.2010.02.005
    Asbtract ( 853 )   PDF (323KB) ( 1610 )  
    Related Articles | Metrics

    The paper deals with the dissolving ability of ZnCl2 aqueous solutions with various mass fractions for cellulose with different degrees of polymerization （DP）. It is found out that （ 1 ） ZnCl2 aqueous solutions cannot dissolve cellulose unless the salt mass fraction is higher than 65.0% ; （ 2 ） when ZnCl2 content is not less than 65.0% , the Zn 2＋ ions unsaturated by water molecules connect with the hydroxyl groups of cellulose, which makes the cellulose to dissolve; and （3） ZnCl2aqueous solution with a content of 65.0% is of the best dissolving ability for cellulose, and the ability decreases with the increase in DP. It is also indicated by WAXD results that the regenerated cellulose is the crystalline transformation of cellulose Ⅱ. Moreover, FT-IR results show that ZnCl2 aqueous solution is a direct solvent for cellulose, and that the intramolecular hydrogen bond of regenerated cellulose weakens after the dissolution.

    Totally-Chlorine-Free Bleaching of Bagasse Pulp
    Liu Yan-lan Chen Ke-fu Li Jun Xu Jun Wang Zhao-jiang Li Wei-wei
    2010, 38(2):  28-31，66.  doi:10.3969/j.issn.1000-565X.2010.02.006
    Asbtract ( 636 )   PDF (349KB) ( 1076 )  
    Related Articles | Metrics

    A short bleaching sequence for bagasse pulp, which includes the oxygen delignification enhanced with hydrogen peroxide（ OP ）, the chelating pretreatment （Q） and the hydrogen peroxide bleaching with pressure （PO）,was investigated. The possibility of obtaining bleached pulp with a brightness of 82% ISO and substituting sodium silicate with non-silica stabilizer in the hydrogen peroxide bleaching was explored. The results indicate that （ 1 ） non-silica stabilizers PP-1 and PP-2 are both suitable for hydrogen peroxide bleaching owing to their resistance to high temperature and pressure ; （2） with a sodium hydroxide dosage of 2. 0% （ relative to oven dry pulp, the same below） and a hydrogen peroxide dosage of O. 5% in Op section, and with a hydrogen peroxide dosage of 3.0%, a PP-1 dosage of 0. 1% and a PP-2 dosage of 0. 5% in Po section, the bleached pulp is of a brightness of 85% ISO;and （3） as no adsorbable organic halogens are found in the OPQPO process, the bleaching effluent can be successfully degraded by organisms.

    Performance of Carboxymethyl Starch Paste and Factors Affecting Paste Transparency
    Zhong Zhen-sheng Sun Ang
    2010, 38(2):  32-38.  doi:10.3969/j.issn.1000-565X.2010.02.007
    Asbtract ( 618 )   PDF (477KB) ( 1277 )  
    Related Articles | Metrics

    Carboxymethyl starch （CMS） with a degree of substitution （DS） of 0. 8901 and with a transparency of 89. 2% was synthesized from potato starch, with ethanol as the solvent. Then, the structure and morphology of potato starch and CMS were characterized by means of FT-IR and ESEM, and the effects of synthesis factors on the transparency of the CMS paste were analyzed. The results indicate that （ 1 ） the transparency of CMS paste is influenced by both the DS and the etherification uniformity; （2） after the carboxymethylation, the transparency of CMS paste increases by 53.8% and the freeze-thaw stability as well as the storage stability improves; （3） the transparency of CMS paste changes slightly in alkaline condition but gradually descends with the increase of acidity ; （4） as for the acid-resistant performance, the CMS with high DS is superior to that with low DS; and （5） as for the influences of food additives, sodium chloride and citric acid both reduce the paste transparency, while glucose and sucrose have an opposite effect.

    Mechanical Engineering
    Energy Consumption Analysis of Injection Molding Process with Hydraulic Pulsation
    Zhao Xiao-qiang Qu Jin-ping Wang Quan
    2010, 38(2):  39-43.  doi:10.3969/j.issn.1000-565X.2010.02.008
    Asbtract ( 601 )   PDF (315KB) ( 797 )  
    Related Articles | Metrics

    In order to reduce the overall energy consumption of the injection molding process with hydraulic pulsation, the effect of axial vibration of screw on the energy consumption of each stage in the molding process is investigated. Then, a mathematical model is established to describe the melted plastic crossing through the pipe runner, and the corresponding energy consumption formula is deduced. Moreover, the influence of axial vibration amplitude of screw on the overall energy consumption is analyzed. Theoretical analysis and experimental results show that （ 1 ） the overall energy consumption of the injection molding process decreases due to the introduction of vibration force field; （2） the energy consumption decreases with the increase in axial vibration amplitude in a certain range; and （3） there is an optimal amplitude corresponding to the lowest energy-consumption.

    Effect of Vibration Force Filed on Power Consumption Dynamic Processing of Polymers
    Yang Zhi-tao Qu Jin-ping Wei Bao-hua
    2010, 38(2):  44-48.  doi:10.3969/j.issn.1000-565X.2010.02.009
    Asbtract ( 591 )   PDF (326KB) ( 965 )  
    Related Articles | Metrics

    In order to explore the influence law of dynamic processing parameters of polymers on the power consumption, the response of electromotor power consumption of a self-designed coaxial-barrel dynamic rheometer （CBDR） to the vibration force field was analyzed based on the melt conveying model, and a theoretical model describing the power difference between the dynamic output and the steady output was established. Then, the electromotor power consumption of the CBDR was measured and was compared with the theoretical one. It is found that the proposed theoretical model is effective in predicting the change of practical electromotor power consumption with vibration parameters. The experimental and theoretical results indicate that the power consumption decreases with the increase in vibration frequency and amplitude. Moreover, the feasibility of the proposed model is verified by the actual change of energy consumption of vibration injection machine.

    Spin-Forming Mechanism of Cup-Shaped Thin-Walled Trapezoidal Inner Gear
    Sun Ling-yan Ye Bang-yan Hao Shao-hua Xia Qin-xiang
    2010, 38(2):  49-54.  doi:10.3969/j.issn.1000-565X.2010.02.010
    Asbtract ( 663 )   PDF (448KB) ( 832 )  
    Related Articles | Metrics

    As compared with the conventional flow forming of tube-shaped parts, the spin-forming of cup-shaped thin-walled trapezoidal inner gear is more complicated. In order to improve the forming quality of inner gears and lay a foundation for the selection of forming parameters, numerical simulation and processing experiment were performed to analyze the material flow during the spinning and the corresponding forming mechanism. The results show that （ 1 ） the spin-forming of inner gears is an upset-extrusion process ; （2） the deformation distribution is periodical, nonuniform and dissymmetric ; （3） the forming of gear tooth is influenced by the rotation direction of the main spindle, and forming defects easily occur during the spinning.

    Effect of Large Cutting Deformation on Microstructure and Hardness of Material
    Wu Chun-ling Ye Bang-yan Wu Bo
    2010, 38(2):  55-59.  doi:10.3969/j.issn.1000-565X.2010.02.011
    Asbtract ( 618 )   PDF (344KB) ( 954 )  
    Related Articles | Metrics

    During the metal cutting process, ultrafine-grained chips may form owing to the severe shear deformation, thus resulting in higher hardness and strength for the chips. In this paper, the variations of the shear strain imposed on the chips as well as on the microstrueture and the hardness of chips under the condition of different tool rake angles and various cutting velocities are investigated for different metals and alloys. Experimental results indicate that   with the decrease of the tool rake angle, the microstructure of chips are significantly refined and the hardness of chips is greatly improved;   the effect of the cutting velocity on the microstructure and the hardness is opposite to that of the tool rake angle ;   ultrafine-grained chip materials with high hardness can be obtained by cutting with a negative tool rake angle at a lower cutting velocity; and   the increase in cutting velocity alleviates the improvement of hardness owing to the large shear deformation.

    Simulation of Cathode Modification for Electrochemical Machining of Blade Based on Neural Network
    Zhu Dong Zhu Di Xu Zheng-yang
    2010, 38(2):  60-66.  doi:10.3969/j.issn.1000-565X.2010.02.012
    Asbtract ( 594 )   PDF (465KB) ( 976 )  
    Related Articles | Metrics

    The accurate design and modification of cathode is one of the key problems in electrochemical machining （ECM）. In this paper, a digital cathode modification model is established based on the improved BP neural network, which substitutes a digital modification, changes the conventional manual correction method and remarkably increases the efficiency of the cathode modification process. In this study, the correction value of the cathode surface is predicted according to the data of multiple cathode modifications. The results show that the proposed model is effective in cathode modification, with a maximum absolute error between the predicted correction value and the actual one of only about 0. 015 mm, and that it can be widely used to the digital cathode modification of complex surfaces such as aeroengine blade, with greatly-reduced modification time and modification period as well as an improved electrochemical machining accuracy.

    Application of Neural Network to Fault Diagnosis of Hoist
    Lei Yong-tao Yang Zhao-jian
    2010, 38(2):  67-72.  doi:10.3969/j.issn.1000-565X.2010.02.013
    Asbtract ( 559 )   PDF (393KB) ( 1424 )  
    Related Articles | Metrics

    Proposed in this paper is a two-level fault diagnosis procedure of hoist. In the first-level diagnosis, fault samples of hoist are collected and designed based on the experience and knowledge of experts and on a fault tree of the brake system, and seven kinds of failure modes of the brake system are automatically classified with SOM network. In the second-level diagnosis, a fault tree of sub-system-hydraulic station is built and the corresponding fault samples are collected and designed. Afterwards, the cause and degree of the hydraulic station fault are determined based on the diagnosis with BP network, BP network state classifier and Elman network. Test results of the hydraulic station fault show that （ 1 ） the structures, the intelligent algorithm trainlm, the inputs and outputs of the three above-mentioned networks all meet the requirements of fault diagnosis and prediction ; （2） Elman network is of the most stable diagnosis performance slightly affected by the number of hidden layer neurons; and （3） BP network state classifier is of the highest test precision while Elman network is of the lowest one.

    Parameter Identification of On-Orbit-Servicing Dual-Arm Space Robot
    Tian Fu-yang Wu Hong-tao Zhao Da-xu Cheng Shi-li Sun Hong-li
    2010, 38(2):  73-77，84.  doi:10.3969/j.issn.1000-565X.2010.02.014
    Asbtract ( 634 )   PDF (373KB) ( 964 )  
    Related Articles | Metrics

    This paper is concerned with the on-orbit-servicing free-floating dual-arm space robot and performs parameter identifications respectively for the robot base and the handling process of an unknown target satellite by one manipulator with the other manipulator hanging in the space. The identification is based on the conservation laws of linear and angular momentums, and it takes into consideration the linear and angle velocities of robot base centroid measured by the sensor that is mounted on the robot base. In the investigation, the space robot is symbolically modeled. Some methods to avoid the singularity of a set of linear equations during the identification of inertias are presented, and the effects of robot parameters on the identification are revealed. A numerical simulation is finally performed to verify the feasibility and effectiveness of the proposed parameter identification methods.

    Resource Trade in Manufacturing Grid Based on Perfect Bayesian Equilibrium
    Zhang Hai-jun Hu Ye-fa Zhou Zu-de
    2010, 38(2):  78-84.  doi:10.3969/j.issn.1000-565X.2010.02.015
    Asbtract ( 574 )   PDF (464KB) ( 772 )  
    Related Articles | Metrics

    In the manufacturing grid （MGrid） resource market, some resource service providers （RSPs） with resource information superiority tend to make a pooling equilibrium. Therefore, resource service demanders （RSDs） cannot evaluate resource quality owing to the imperfect information. In order to solve this problem, this paper proposes a resource trading approach of manufacturing grid based on the perfect Bayesian equilibrium. In this approach, with the support of MGrid system architecture, RSPs promise a compensation for the display of resource quality, thus achieving in separating equilibrium and preventing low-quality RSPs from sending out a higher compensation that high-quality RSPs would promise. Simulated results show that the proposed game model achieves a stable, reasonable and perfect Bayesian separating equilibrium, from which RSPs would not deviate initiatively.

    Self-Organization of Networked Manufacturing Information System
    Zhang Kai-sheng Liu Gui-jie Zhang Qing-li Sun Yan-ming
    2010, 38(2):  85-89.  doi:10.3969/j.issn.1000-565X.2010.02.016
    Asbtract ( 595 )   PDF (466KB) ( 935 )  
    Related Articles | Metrics

    This paper investigates the self-organization conditions and process of networked manufacturing information system （NMIS） based on the self-organization theory and methods. In order to analyze the relationship between macroscopic relative stability and unit action and to reveal the self-organization essentials of NMIS, a servo constraint function is proposed and is then used to illustrate the servo function of macroscopic order parameters for the units＇ self-interaction and interaction. Moreover, by taking the information system of a mould production line in a manufacturing enterprise as the platform, a comparison between the simulation and the operation results is performed, by which the effectiveness of the proposed model is verified. The proposed model can be used to analyze, plan, optimize, and design the information system to be constructed, and it helps to accelerate the informatization of manufacturing enterprises as well as promote the quality of their work.

    Simulation Modeling of Nitrogen-Inflating Hydraulic Hammer
    Ding Wen-si Huang Xiao-dong
    2010, 38(2):  90-94.  doi:10.3969/j.issn.1000-565X.2010.02.017
    Asbtract ( 752 )   PDF (320KB) ( 979 )  
    Related Articles | Metrics

    In order to analyze the impact energy-controlling performance of nitrogen-inflating hydraulic hammer, the power bond graphs of both the stroke and the backhaul are presented based on the theory of power bond, and the state equations of the nitrogen-inflating hydraulic hammer are established. Afterwards, a simulation model, which takes into consideration the high-frequency variation of motion state of hydraulic hammer and realizes the fast calculation of main simulation parameters, is built in the AMESIM system. Then, a simulation is performed using the existing design parameters of DBS500 hydraulic hammer, and the error between the simulated and the test results is found to be less then 6%. It is thus concluded that the proposed model is basically correct and reliable.

    Calculation of Leakage Dynamic Seals and Friction of Combined Based on ADINA
    Cui Xiao Dong Yan-liang Zhao Ke-ding
    2010, 38(2):  95-100.  doi:10.3969/j.issn.1000-565X.2010.02.018
    Asbtract ( 601 )   PDF (420KB) ( 1049 )  
    Related Articles | Metrics

    In order to quantitatively analyze the internal leakage of high-precision electrohydraulic servomotor, a numerical method to solve the oil-film control equation is proposed based on the finite element method. In this method, the contact stress on the seal surface is calculated with the finite element software ADINA; the oil film thickness is obtained by solving the one-dimension Reynolds equation with the inverse method; and the leakage and the friction are also calculated. Then, in order to overcome the difficulty in determining the inflection point of the two-order derivative pressure function, a cubic polynomial is used to fit the pressure at the inlet. Moreover, the effects of O-ring pre-compression ratio, medium pressure, rotor radius, motor velocity and temperature on the leakage and the friction are analyzed. The results indicate that the proposed numerical method is more stable and effective than the conventional iterative method. It is applicable for the calculation of leakage and friction of electrohydraulic servomotor, and it lays a theoretical foundation for the design of elastomeric seals.

    Electronics, Communication & Automation Technology
    Performance of Cognitive Radio Networks with Different Packet Level Policies
    Zhang Min Wei Gang He Chun-xiong Wang Hong-jiang
    2010, 38(2):  101-105,131.  doi:10.3969/j.issn.1000-565X.2010.02.019
    Asbtract ( 712 )   PDF (321KB) ( 1025 )  
    Related Articles | Metrics

    In this paper, the performances of cognitive radio networks with different packet level policies for secondary users are analyzed, and two models for cognitive radio networks are proposed to derive the formulas of packet loss ratio, packet delay, throughput and spectrum utilization for secondary users. Moreover, a performance simulation is carried out to evaluate the accuracy of the proposed theoretical models. Analysis and simulation results indicate that （ 1 ） the proposed models can accurately evaluate the performance of cognitive radio networks ; （2） the packet loss ratio, packet delay and spectrum utilization of secondary users all increase with the arrival rates of services; （3） cognitive radio networks help to improve the spectrum utilization remarkably; and （4） the difference in packet level policy of secondary users affects the spectrum utilization slightly but it exerts significant effects on the throughput.

    Real-time Intra-Task Voltage Scheduling Algorithm for Wireless Sensor Networks
    Chen Jie Yi Ben-shun Fang Yan-jun Yue Lin
    2010, 38(2):  106-110.  doi:10.3969/j.issn.1000-565X.2010.02.020
    Asbtract ( 641 )   PDF (357KB) ( 821 )  
    Related Articles | Metrics

    This paper proposes a low power real-time dynamic voltage scaling algorithm with low power consumption for the energy-efficient design in the applications of wireless sensor networks which require collaborative processing executed in parallel on sensor nodes. In this algorithm, a single-task processing model of nodes is established and used to reflect the influences of associated communication events on the processing of tasks, and an optimal intratask voltage scheduling strategy is introduced to obtain the ideal operation frequency （or voltage ） of each basic block in the model. Afterwards, a frequency split method is proposed to effectively eliminate the slack time between the task completion time and the deadline. The implementation method of the proposed algorithm is also presented and the effectiveness of the algorithm in reducing the energy consumption of nodes is finally verified through a simulation.

    An Adaptive Modulation OFDM Algorithm with Data Spread
    Zhang Yan-ling Sun Xian-pu Li Jian-dong
    2010, 38(2):  111-115.  doi:10.3969/j.issn.1000-565X.2010.02.021
    Asbtract ( 617 )   PDF (311KB) ( 782 )  
    Related Articles | Metrics

    In traditional orthogonal frequency division multiplexing （OFDM） systems, the realization of adaptive modulation needs to transfer a great deal of sub-carrier modulation parameters, which may decrease the transmission efficiency. In order to solve this problem, this paper analyzes the characteristics of adaptive modulation OFDM systems with data spread, and points out that an optimal algorithm is to assign the bits and power among original data symbols averagely. From this viewpoint, an adaptive modulation algorithm orientated to users＇ requirements with a minimum total power is proposed. In this new algorithm, two different constellations are adopted at most to assign the original data symbols in order. Thus, the complexity of the algorithm is greatly reduced and the transmission of modulation parameters is obviously decreased. Simulated results indicate that the proposed algorithm is good in performance, and that it saves about 2 dB power （represented by the average signal-to-noise ratio of the sub-carrier） , as compared with the traditional adaptive power control-based OFDM system with similar complexity.

    Fast Synchronization for M-Ary Orthogonal Spread Spectrum
    Xiong Hai-liang Li Wen-gang Sun De-chun Yang Hong Yi Ke-chu
    2010, 38(2):  116-120.  doi:10.3969/j.issn.1000-565X.2010.02.022
    Asbtract ( 642 )   PDF (338KB) ( 890 )  
    Related Articles | Metrics

    Proposed in this paper is a novel method of M-ary orthogonal spread spectrum, with which the potential periodicity of transmitted signals is eliminated and the data are hard to detect or intercept. Thus, both the anti-jamming and the anti-intercept capabilities of the system are well guaranteed. In the condition of long pseudo code and large carrier Doppler frequency shift, the number of FFT points in the conventional synchronous acquisition algorithm is too large, the complex multiplication is of high computational complexity and large time cost, and the parameter evaluation acquired in a long duration is not applicable for carrier tracking because it is too old. In order to solve these problems, an improved fast synchronous acquisition algorithm is proposed, which helps to search for the code synchronization point and estimate the cartier frequency offset for correction, with the computational complexity obviously reduced.

    Detection Model of Geometric Shape of Lip Based on PS-Level Set
    Feng Xiao-hui He Qian-hua Wang Wei-ning Yan Le-pin
    2010, 38(2):  121-125.  doi:10.3969/j.issn.1000-565X.2010.02.023
    Asbtract ( 630 )   PDF (371KB) ( 993 )  
    Related Articles | Metrics

    In order to overcome the overconvergence and the premature convergence of lip boundary caused by the level set model for geometric shape detection, an improved level set model based on the prior shape （ PS-Level Set） is proposed. In this model, the prior shape information of lip is incorporated into an improved differential energy function, and the differences between the evolution shape curve and the prior shape curve are repeatedly compared during the curve-evolving process, which enables the evolution shape to gradually approach the prior one and to converge to the target object more accurately. Experimental results show that, as compared with the conventional level set model, the proposed model improves the detection accuracy by 8.38%.

    Feature Extraction Algorithm of Block Edge Pattern Based on H. 264 I-Frame Coding
    Feng Jie Chen Yao-wu
    2010, 38(2):  126-131.  doi:10.3969/j.issn.1000-565X.2010.02.024
    Asbtract ( 648 )   PDF (423KB) ( 1027 )  
    Related Articles | Metrics

    This paper proposes a feature extraction algorithm for the block edge pattern from H. 264 I-frame bit streams and verifies the extracted features by image retrieval applications. In the proposed algorithm, five block edge patterns are extracted based on the intra prediction mode and the prediction coefficients from H. 264 bit streams, which accord with the edge descriptor in MPEG-7 and are suitable for content-based image retrieval algorithms. Experimental results show that the image retrieval based on the extracted features is relatively precise, and the average precision is 5.07% higher than that of the retrieval based only on the texture descriptor of intra prediction mode.

    Corner Detection of Image Based on Product of Two Bending Degrees
    Liao Wen-zhi Pi You-guo
    2010, 38(2):  132-136,148.  doi:10.3969/j.issn.1000-565X.2010.02.025
    Asbtract ( 858 )   PDF (364KB) ( 1405 )  
    Related Articles | Metrics

    As the difference in bending degree between comer points and non-corner points is not large enough for image detection, an algorithm of image comer detection based on the product of two bending degrees is proposed. The proposed algorithm enlarges the differences in bending degree by multiplying the first bending degree and the second bending degree. Then, the comer detection for digital images is conducted. Experimental results show that the proposed algorithm is simple and effective, and that it helps to detect image comers with good stability and high precision.

    Optimal Control of Wastewater Treatment Process Based on Novel Immune Algorithm
    Ye Hong-tao Luo Fei Xu Yu-ge Yang Hong Liang Jin
    2010, 38(2):  137-141.  doi:10.3969/j.issn.1000-565X.2010.02.026
    Asbtract ( 726 )   PDF (310KB) ( 1191 )  
    Related Articles | Metrics

    In order to improve the distribution diversity of antibodies, a novel immune selection operator combining the antibody concentration and the sufficiency vector distance is proposed, and a scale-variable hybrid mutation operator, which introduces the mutative scale method in the hybrid mutation, is designed to improve the search efficiency. The convergence, stability and complexity of the algorithm are then analyzed, and an optimal control of operation cost is performed with the algorithm for wastewater treatment. Experimental results indicate that the proposed method is of high effectiveness, global convergence reliability and velocity.

    A Multiple-RBF Neural Network Model to Set Rolling Force Based on Wavelet Analysis
    Chen Zhi-ming Luo Fei Cao Jian-zhong
    2010, 38(2):  142-148.  doi:10.3969/j.issn.1000-565X.2010.02.027
    Asbtract ( 645 )   PDF (465KB) ( 785 )  
    Related Articles | Metrics

    During the setting of rolling factors with complicated correlation. It force in continuous hot strip rolling, force signals are influenced by is, therefore, difficult to establish an accurate model to describe the various rolling mechanism. In order to solve this problem, a multi-RBF neural network model is proposed. In this new model, the multi-resolution wavelet analysis method is employed to separate the rolling force signal into several sub-signals corresponding to different factors, and several RBF neural networks are established, each for a certain sub-signal. All the outputs of the sub-networks are integrated into a rolling force signal, and both the input and the output of each network relate to the affecting factors of the corresponding sub-signal. Thus, the sub-networks can well reflect the variation mechanism of the rolling force. Simulated results show that the proposed model decreases the number of system dimensions, improves the learning ability of the network, and reduces the error rate of rolling force setting from the original 10% in BP neural network model to 5%.

News
 
More>>
Featured Article
More>>
Most Read
More>>
Most Download
More>>
Most Cited
More>>
Links
More>>