Table of Content

25 November 2006, Volume 34 Issue 11

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Mechanical Engineering

Cutting Heat Dissipation in High-Speed Machining of Carbon Steel Based on Calorimetrilc Method

Quan Yan-ming He Zhen-wei Dou Yong

2006, 34(11):  1-4. 

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The cutting heat dissipation in the chips,the workpiece,the tool and the surroundings during the highspeed machining of carbon steel was quantitatively investigated based on the calorimetric method.In the investiga-tion,water was utilized as the medium to absorb the cutting heat,a serf-designed container suitable for the highspeed lathe was used to collect the chips,and two other containers were respectively adopted to absorb the cutting heat dissipated in the workpiece and the tool.The temperature variations of the water,the chips,the workpiece,the tool and the suroundings during the closed high-speed machining were then measured.Thus,the cutting heat dissipated in each component of the cutting system,the total cutting heat as well as heat flux were calculated.More-over,the power resulting from the main cutting force was obtained according to the measured cutting force and the predetermined cutting speed.The accuracy of Cutting heat measurement by the calorimetric method was finally evaluated by comparing the total cutting heat flux with the power resuhing from the main cutting force.

Analysis of Dynamic Resistance Waveforms in Arc Welding

Xue Jia-xiang Dong Fei Wang Zhen-min Yang San-guo Hong Sen

2006, 34(11):  5-9. 

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The welding processes of two CO₂ arc-welding machines were tested and analyzed using a self-developed welding dynamic arc wavelet analyzer.The results indicate that the integrated electric characteristics of welding power can be reflected by the dynamic resistance,that the dynamic resistance should quickly increase to a stable value to make the striking successful,that the ripple interference of dynamic resistance should be reduced and the
peak value of dynamic resistance should remain constant in a certain period to realize a smooth droplet transfer in the welding process,and that the dynamic resistance should smoothly increase from the peak value to a infinite value in a transition cycle to avoid an abrupt ascend in the process of arc extinguishing.All these results lay a founda-tion for the improvement of arc welding technology and arc waveform control.

Hydroforming Process of T-Shaped Tube Driven by Axial Displacement at Tube End

Li Shuang-gao Gao Lin Wang Hui Li Bo

2006, 34(11):  10-15. 

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In order to produce high-quality parts by the tube hydroforming figuration(THF),the pressure in the tube should precisely fit the axial displacement at the tube end,and expensive hydraulic equipment is a necessary part.To solve this problem ,a simple method,namely displacement-driven THF,is presented for T-shaped tubes according to the results of finite element simulation and experiments.This method is based on the characteristic that
the tube volume continuously decreases in the THF process.The efect of overfall pressure on the forming result,as well as the reason for wrinkling,was then discussed,and the concept of safe forming zone was proposed.Experi-mental results indicate that,as the proposed method is a simple method without special requirements for equipment,the THF equipment and the process are simplified and the production cost is reduced.

Experimental Research on Jet Electroforming Oriented by Rapid Manufacturing

Chen Jin-song Huang Yin-hui Liu Zhi-dong Tian Zong-jun Zhao Yang-pei

2006, 34(11):  16-19,24. 

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The principles and system components of the jet electroforming 0rientated by rapid manufacturing were introduced,and some nanocyrstalline copper parts with simple shapes were fabricated by the introduced technology.SEM and XRD were then used to analyze the mierostructure of the nanocrystalline.The t-esuhs sh0w chat the iet kctrolorming greatly Increases the ultimate curent density,fines crystalline particles and improves the depositionquality.Moreover,the deposited copper layers are all of nanocrystalline micmstructure,with an average size of
55.6nm and a minimum size of4.4nm

Design of PFC Inductor in Variable·Frequency Air-Conditioner

Zeng Min J iang Li-xin Jiang Wei

2006, 34(11):  20-24. 

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The application of the power factor correction(PFC)circuit to the variable-frequency air-c0nditi0ner is introduced,together with discussing the advantages and the principles of a PFC module with 3.3 kW input power.Moreover,the design of an amorphous magnetic PFC inductor is analyzed in detail.including the calculati0n of the critical inductance,the selection of the magnetic material and the specification determinati0n of the magnetic core.Experimental results show that the designed inductor composed of Fe based amorl)hous magnetic material can meet the requirements of variable-frequency air-conditioner due to its high saturated magnet density and the good heat stability of the material.

3D Numerical Simulation of Oil-W ater Separation in Hydrocyclone

Huang Si

2006, 34(11):  25-28,38. 

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The numerical simulation of the two.phase turbulent flow in a hydrocyclone is generallv carried Out for the phase with a concentration less than 10% (volume fraction)due to the limit of simulati0n models.To solve this problem,this paper develops a 3 D numerical simulation of the oil.water separation in a hydrocycl0ne bv using the Fluent software and by combining the Eulerian muhiphase.flow model with the anisotropic Reynolds.stress turbu.lence model,thus evaluating the coresponding separation eficiency.The proposed method can be applied to the simulation concerning the phase with a concentration over 10% and with an anisotropic turbulent flow.It can alsoexpose the separation,aggregation and shift of the homogeneous oil and water flow in a hydrocyclone. The corect.ness of the evaluated separation efficiency is finally verified by the measurement resuIts

Partial Least-Square Regressive Analysis and M odeling of Ultraweak Photon Emission of Fish

Liu Gui-xiong Lin Xu-hong

2006, 34(11):  29-32. 

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According to the theory of uhraweak photon emission(UPE)of organisms,the paItial least square re.glession(PLSR)method is used to analyze the major factors to affect the UPE of fish in the propagation period.An equation to evaluate the UPE is then established,and the physical meanings of all the regressive coeficients in the equation are illustrated.Moreover,the primary and secondary factors to affect the UPE of fish are determined. thus coming to the conclusions from the analysis of the PLSR model that the temperature and the gonad maturation coeffi.cient are two notable factors to afect the UPE of fish,and that the avoirdupois, the mass of gonad.the illumination and the salinity have weaker effect on the UPE,especially the latter two

Bond Graph M ethod to Investigate Coupling Dynami of Complex Flexible M ulti-body System

Wang Zhong-shuang Lu Nian-li

2006, 34(11):  33-38. 

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In order to improve the efficiency and reliability of the dynamics analysis for the cornplex Dlanar linkage containing the coupling of multiple energy domains.a method named bond graph is introduced.The general proce.dure to establish the bond graph model considering the coupling of the rigidity,the flexibility and multiple energy domains in a non-inertial coordinate system is then proposed.The unified expressions for the state.space equati0ns 0f the system and the constraint forces at the joints,which can be easily auto generated by a computer,are also de.duced．The constraint forces at the joints can be loaded on the corresponding O-junctions in the bond graph model as an unknown effort source.As a resuh,the difficult algebraic problem resulting from the nonlinear iunction struc.ture and the differential causality is solved,and the automatic modeling and simulation by a computer are realized .Through a practical example,the validity of the proposed bond graph method is finally verifie

Open Modular Design Methodology of Plastic Injector for Enterprise·Cluster M anufacturing

Hu Kai-shun Ye Bang-yah Wang Wei-ping

2006, 34(11):  39-44. 

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This paper analyzes the characteristics of the enterprise-cluster manufacturing system and proposes an open modular product design methodology by dividing the producing technologies into technology cells and by selec-ting the most valuable technology module.In the proposed methodology ,a reasonable technology division is realized by the structure-mapping function based on technologies and by the technology cell clustering based on the design structure matrix(DSM).Moreover,the selection of a valuable technology module is implemented by the relational analysis of technology modules based on a quantified DSM (QDSM)and by the evaluation of the importance of technology modules.Thus,an open modular product design methodology is presented, which is finally applied to the design of a plastic injector with open modular structure f0r enterprise-cluster manufacturing.

Clustering Algorithm of Product Architecture Modularization Based on Design Structure Matrix

Liu Jian-gang Ma An Wang Ning-sheng

2006, 34(11):  45-48,86. 

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The limitation of the current clustering algorithms of product architecture modularization is discussed in this paper,and it is overcome by a clustering algorithm based on the design structure matrix(DSM).The methods to build the product architecture DSM model are also introduced,and the model is then numericalized bv the five-point scale method.Moreover,a clustering algorithm based on the relation strength and an optimizing algorithm based on the relation cost are developed.A motorcycle engine is finally used as an example to carry out the mode-ling,clustering and optimization,obtaining an optimized clustering model.

A Method to Investigate Control Performance of Distributed Manufacturing Information System

Zhang Kai-sheng Chen Wei Sun Yan-ruing Zheng Shi-xiong

2006, 34(11):  49-54. 

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When the Ramadge-Wonham supervisor and control theory is used to investigate the control performance of distributed manufacturing inform ation system,there exist some problems such as ambiguous physical meaning of the formal language,high computational complexity and too much calculation.In order to get out of these problems,a new method is presented,which form alizes the natural language descriptions of inform ation units,gives the grammar of the form al language and introduces some constraints expressed in the form of Boolean matrix,The automata models of information units produced by the grammar fulfill the necessary control requirements.An assembly robot in the auto-manufacturing line of an enterprise is then used as an example to research the control perform ance of the automata model.It is concluded that the proposed method is of great application value due to its explicit physical meaning of the form al language and low computational complexity.

Automatic Optical Inspection of M ini-Drill Blade Based on Computer Vision Technology

Zhang Wu-jie Li Di Ye Feng

2006, 34(11):  55-59. 

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In order to realize the automatic optical inspection(AOI)of the dimensions and defects of mini.drill blades,an automatic image inspection system is proposed and the corresponding image processing algorithms are in-vestigated.In the investigation,a special lighting system is first designed based on the characteristics of mini-drill blades to obtain clear blade images with little distortion.Next,the improved Small Univalue Segment Assimilating Nucleus edge extraction algorithm is adopted to extract the image edge.Then,the extracted edge is located by the subpixel edge location algorithm based on the spatial moments to obtain a precise Subpixel location.Finally,the algo-rithms,such as the line fitting and the circle fitting,are adopted to calculate the dimensions and to inspect the de-fects of the mini-drill blades.Experimental results demonstrate that the proposed AOI method is of an inspection ac-curacy of 99.5% and a dimension precision in the scale of micron.so it can meet the requirements of dimension measurement and defect inspection of mini-drill blades.

Trajectory Tracking Control of Car-Like Mobile Robot Based on Integrated Steering

Zhao Yi-hong Zhu Jian-ying

2006, 34(11):  60-63. 

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The problem of trajectory tracking of an uncertain car-like mobile robot with nonholonomic constraints is analyzed,and an adaptive trajectory tracking control method is presented based on the analyses of kinematic mo-dels.In the Droposed control method,a state diferential feedback procedure is used to stabilize the robot and an artificial field combined with the posture error is introduced to navigate the robot.The robustness of the proposed controller is then confirmed by means of Lyapunov stability theory.Simulated results of the robot respectively tIlacking a line and a circle indicate that the proposed method enables the robot to track an ideal trajectory in the navigation.

Mathematical Sciences

Positive Solution to Asymptotically with M ultiple Critical Linear Elliptic Equation Potentials

Shen Yao-tian Liu Ai-rong Zhai Yong-hong

2006, 34(11):  105-108. 

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This paper discusses the existence of the positive solution to an asymptotically linear elliptic equation with muhiple critical potentials in Sobolev,Hardy space.As the fight term of the equation is asymptotically linear and does not satisfy the Ambrosetti-Rabinowitz condition,the Mountain Pass Theorem without Palais-Smale condition is used to prove that the equation is of at least one positive solution in a weaker condition.

Graph Classification for a Class of Quintic Algebra Curves

Wang Quart-di Zhang Jin-huan

2006, 34(11):  109-113. 

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The graph classification for a class of quintic algebra curves is carried out by means of the software Mathe-matica and the qualitative analysis method of planar dynamical system.In the classification,first,a planar dynami-cal system corresponding to the quintic algebra curves is constructed.Next,the distributions and properties of sin-gular points are studied.Then,the bifurcation curves are given on the parametric plane.Finally,the graphs of the algebral curves are drawn by using the software Mathematica.Thus,the classification is completed,dividing the graphs into twelve types.

Blow-Up Rate of a Degenerate Reaction-Difusion System

Du Li-li Xia An-yin Fan Ming-shu

2006, 34(11):  114-116. 

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This paper,in which the blow-up rate of the blow-up solutions is evaluated with appropriate hypotheses,considers the blow-up rate of a degenerate reaction-diffusion system with homogeneous Dirichlet boundary condi-tions.

Liquidity Risk-Adjusted Credit Default Swap Pricing

Ren Zhao-zhang Li Peng

2006, 34(11):  117-122. 

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A pricing model of defaultable bond considering the liquidity risk is proposed according to the empirical literature concerning the credit spread puzzle.This model separates default risk and the liquidity risk involved in bond prices,thus resulting in a liquidity risk-adjusted credit default swap pricing.As the disturbance from the liquidity risk is eliminated,the pricing of the credit default swap with great accuracy is implemented.Meanwhile,the default strength parameters with and without liquidity risk are respectively considered according to the data from Chinese corporate bond market,and the corresponding credit default swap prices are calculated.The results indi-cate that the neglect of liquidity risk will results in the overestimation of default probability of high-rated bonds,especially those with short maturities,thus further resulting in an overestimation of initial credit default swap prices

Application of Fractal W avelet to Foreign Exchange Investment M arket

Xi Zhen-fel Song Guo-xiang

2006, 34(11):  123-126. 

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in order to analyze and evaluate the tendency of foreign exchange market and to provide decision basis the foreign exchange control,two methods,namely the wavelet transform and the multi.differentiation analysis.are adopted tO reveal a self-similarity and a fractal characteristic of the variation of foreign exchange prices. Then,a fractal interpolation model is put forward for the foreign exchange sequencing ,and an interpolated iterative algo-rithm is presented to predict the tendency of the foreign exchange market.The analysis of practical cases shows that the proposed fractal interpolation method is better than the traditional interpolation methods in the approaching to the foreign exchange curve.it makes possible the prediction of future foreign exchange market

Architecture & Civil Engineering

Fire Resistance of High-Strength Concrete Column

Wu Bo Hong Zhou

2006, 34(11):  64-69. 

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A full-process analytical proposed,in which the effect of expl bility of the program is validated by parameters on the fire resistances of program for high-strength concrete columns subjected to high temperature is osive spalling of high-strength concrete is approximately considered.The relia-the test results of other researchers．In order to reveal the effects of the main high-strength concrete columns.480 specimens with different axial loading ratios,cross-section dimensions,reinforcement ratios and load eccentricity ratios are selected to analyze the high-tem-perature reaction of the high·strength concrete columns.The results are then compared with those of common con-crete columns.Moreover,a simplified way to quantitatively determine the fire resistance of high-strength concrete columns is presented based on the simulated results.It is indicated that the explosive spalling has significant influence on the fire resistance of high-strength concrete columns,and that the fire resistance of the high-strength concrete columns with both central axial loading and eccentric axial loading can be effectively improved by reducing the axial loading ratio and the load eccentricity ratio,and by increasing the cross-section dimension.

Experimental Investigation into Draining Consolidation Behavior of Soda Residue Soil Under Vacuum Preloading-Electro-Osmosis

Fang Ying-guang Xu Min Zhu Zhong-wei

2006, 34(11):  70-75. 

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This paper deals with some contrast experiments to compare the draining consolidation eficiency of the vacuum preloading(VP)method and the vacuum preloading-electro-osmosis(VPE)method with soda residue soil as the medium.and analyzes the mechanism of draining consolidation caused by the VPE method.It is indicated by indoor model tests that both the two methods are of obvious draining effect on soda residue soil,especially the VPE method,that the VPE method possesses obvious draining effect even after the drainage has been finished,and that the mechanism of draining consolidation caused by the VPE method lies in the seepage flow under waterhead gradi-ent and electric field,which results in a higher draining velocity and a larger consolidation amount.The cxpcrimcntal results on the soda residue soil are also useful to the foundation consolidation of soft soil.

Integrated Evaluation of Factors to Afect Liquefaction of Sandy Soil Based on BP Neural Network

Pan Jian Liu Li-yan Lin Hui-chang

2006, 34(11):  76-80. 

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In order to investigate various factors to affect the liquefaction of sandy soil.different BP neural network models for liquefaction evaluation were established based on different combinationS 0f the input neurons.A BP neural network-based program,namely SLV,was then presented for the liquefaction evaluation of saturated sandv soil.Some comparison analyses were finally carried out according to the results of field observation.It is shown that the earthquake action is a direct cause of the liquefaction ,that the saturation state of sandy soil is the precondition of the liquefaction,and that the standard penetration blow.count,the non.uniformity coefficient and the shearing stress ratio are the main influencing factors of the liquefaction.Moreover , it is indicated that the proposed BP neural net.work model can efectively evaluate the factors to affect the liquefaction of sandy soil due to its strong classifying and distinguishing ability.

Response Modification Factors of Shear W alls in Diferent Performance Levels

2006, 34(11):  81-86. 

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In this paper,the response modification factors(RMFs)of reinforced concrete shear walls in different performance levels are first determ ined according to the difference in seismic capacity of the walls under different perform ance statuses.Next,on the basis of the edge strain statuses of the concrete and the vertical steel in the plas-tic hinge region,the flexure destruction response of a single cantilever ductility shear wall is divided into four per-form ance levels,and the calculation methods of the corresponding RMFs are put forward.Then,the perform ance level lying behind the conventional seismic design procedures is manifested according to the calculated edge strain by imposing the equivalent load of the earthquake action on the shear walls.It is finally concluded that,in the per-formance-based seismic design.the RMFs of the shear walls can be used to adjust the equivalent load of the earth-quake action,SO that the perform ance level can be approximately obtained by following the conventional seismic de-sign procedures.

Experimental Investigation into Axial Compressive Behavior of L-Shaped Concrete-Filled Steel Tubular Stub Columns with Binding Bars

Long Yue-ling Cai Jian

2006, 34(11):  87-92. 

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The axial compressive experiments of seven L-shaped concrete-filled steel tubular stub columns.six with and one without binding bars,were carried out.The efects of tube wall thickness,the diameter and spacing of the binding bars on the axial compressive behavior of the columns are analyzed.Experimental results indicate that the ultimate strength of the columns with binding bars increases,and that the setting of binding bars improves the con-finement of the concrete core,delays or even avoids the local buckling of the steel tube before the stress attains the yield strength.The ductility of the columns is greatly increased.

Low Flow Simulation of the Dongjiang Basin Based on Xinanjiang Watershed Hydrological Model

Huang Guo-ru Chen Yong-qin

2006, 34(11):  93-98. 

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The daily flow hydrographs of the four catchments in the Dongjiang basin are simulated based on the Xin-anjiang watershed hydrological model,with the aim of revealing the feasibility and precision of the low flow simula-tion using the Xinanjiang watershed hydrological model.The simulated results are then approximately analyzed in terms of the conventional evaluating items,Moreover.the ability of the model to simulate the low flow is assessed bv investigating several low flow characteristic parameters, such as the minimum average flow at different intervals,the baseflow separation results,the simulated results in the low flow period and the flow duration curves. The resuhs of the four catchments indicate that the Xinanjiang watershed hydrological model can effectively evaluate the low flow of the Dongiiang basin concerning the conventional items and the low flow criteria because of its high precision.

Numerical Analysis of Singular Heat Flux Field(Ⅰ):Eignenproblems of Heat Conduction

Wang Hai-tao Yang Xiao-mei

2006, 34(11):  99-104. 

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In order to get a finite element formulation to analyze singular heat flux fields,the weak form of basic equations and boundary conditions describing the 2D heat conduction eigenproblems is derived for the sectorial domains in the vicinity of the interfacial crack tip.By using the eigenfunction expansion technique,a one-dimension finite element formulation i8 then developed to determ ine the eigensolutions to the 2D heat conduction problem at the crack tip,which discretizes the sectorial domain circumferenially.A global equation is finally obtained as a second’order characteristic matrix equation.By solving this second-order matrix equation,the eigensolutions to the 2D heat conduction problems in singular heat flux fields can be obtained.Numerical examples demonstrate the cor.rectness and efficiency of the proposed method.

Contents

2006, 34(11):  0. 

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