JOUNAL OF XI'AN JIAOTONG UNIVERSITY
Vol.32 No.2 1998
CONTENTS
[Chinese] [Return]

(1)The Hybrid Multipole Theory-BEM in Electrostatic Field Computation
.................................................Zheng Qinhong,Sheng Jianni(1)
(2)The Current Mode Filters with Tunable Pass Band Characteristics
...................................................Zhao Luhuai,Qiu Guanyuan(5)
(3)The Effect of Pulse Electomagnetic Fields on Mouse Blood Cells
...................................Zhong Lisheng,Xu Xiaozhou,Xu Chuanxiang(9)
(4)Network Solution of Leakage Magnetic Feild Distribution of Three- Phase Trans- formers
.....................Fan Shuwei,Fang Zhiqiang,Zhang Xingzhi et al(12)
(5)Study and Application of Fuzzy Cluster Neural Network Based on Wavelet Packets and Its Application
..........Zhao Jiyuan,He Zhengjia,Meng Qingfeng et al(15)
(6)A Prediction Model for Two-Body Wear Process .....Liu Fengbi,Xie Youbai(20)
(7)The Processing of Balancing Plane Correlation on Multi-Plane Balancing
............................................. Wang Xiaosheng,Qu Liangsheng(24)
(8)Study on the Controlling Mechanism for the Anti-Drifting Welding Roller Bed
.....................................................Shen Fenggang,Xue Jin(28)
(9)Computer Simulation of Vibroimpact Absorbers
.....................................Li Wei,Chen Tianning,Hu Xuanli et al(32)
(10)The Effects of Thrust Bearing on Lateral Vibration of a Single-Mass Rotor
..........................................................Chen Wei,Zhu Jun(36)
(11)Influence of the Second Surface Metallurgy of Metallic Materials on Vacuum Break down Behaviours
..............Yang Zhimao,Ding Bingjun,Wang Xiaotian(41)
(12)Formation Mechanism of Spherical Pyrolytic Carbon in Process of Rapid CVD
.....................................................Luo Ruiying,Jin Zhihao(46)
(13)Application of COD Criterion to Steel 40CrNiMo Elastic-Plastic Fracture Under Mixed Mode I+II Loading
.............Sha Jiangbo,Deng Zengjie,Zhou Huijiu(48)
(14)Relation between ¦Ã-¦ÅMartensite Transformation Temperature and Compositio n in Fe-Mn-Si-Cr-NiSystem Shape Memory Alloys
....................................Li Chenglao,Liang Gongying,Jin Zhihao(53)
(15)Study of Surface Remelting Alloying and Cladding of Aluminium Alloy by Laser
.............................................................. Zhao Wenzhen(57)
(16)£Ò-Curve (Crack Resistance) Behaviour of Pressureless Sintering Si3N4
.............................. Wang Hongjie,Wang Yonglan,Jin Zhihao et al(62)
(17)Microstructural Analysis of the Weld Joints in 9Cr1MoVNb Steel
.................................. Guo Dazhan,Li Fenlan,Zhu Ruihua et al(66)
(18)Micro and Macro Studies on Creep-Fatigue Properties of 317 Stainless Steel
................................................. Wang ShiwenS,hen Yapeng(71)
(19)Global Attractor and Dimensional Estimate for the Coupled Fitz-Hugh-Nagumo Systems ........................................................Wu Jianhua(74)
(20)A New Continuation Method for Solving Monotone Variational Inequalities
..................................................Liang Ximing,Peng Jigen(78)
(21)An Effective Nonlinear Galerkin Scheme ...........Hou Yanren,Li Kaitai(81)
(22)Galerkin Schemes and Their Analyses for the Problem ofNaturalConvection in an Annular Cavity ..............................................Yang Xiaozhong(86)
(23)On the Convergence of an Ergodic Iteration for the Solution to Monotone Mappings Equation .................................Zhang Zhuosheng,Liu Feng(91)
(24)Preconditioning of Strictly Diagonally Dominant Symmetric Definite Matrix
........................................................... Xiang Shuhuang(94)
(25)Extraordinary Hall Effect for Dilute Magnetic Alloys ....Tian Dongping(98)
(26)The Analysis of Internal Resistance and External Force on Technological Innovation in Enterprises............................ An Liren,Xi Youmin(103)
·Research Notes·
(27)Nonlinear Adaptive Filtering in Spread Spectri Communications
......................................Li Guorong,Yan Hongsen,Zhu Shihua(108)

The Hybrid Multipole Theory-BEM in Electrostatic Field Computation
Zheng Qinhong,Sheng Jianni
(Xi'an Jiaotong University,710049,Xi'an)
[return]

Abstract This paper deduces the hybrid MT(Multipole Theroy) BEM formula and gives the application condition for solving the electrost atic field problem. By calculating and analyzing two examples,it is proved tha t the hybrid MT?BEM is reliable and has higher accuracy than that of other me thods. It can be used to analyze the electrical field in electrical engineer ing and can also be used to solve Poisson equation of boundary-value problems.
Keywords multipole theory,boundary element method,hybrid method ,electrostatic field

The Current Mode Filters with Tunable Pass Band Characteristics
Zhao Luhuai,Qiu Guanyuan
(Xi'an Jiaotong University,710049,Xi'an)
[return]

Abstract A novel current mode integrator whose time constant is controlled dy a voltage is presented. The filters using the integrator can remedy the nonideal effects of the integrator partly or totally,and are suitable for the adaptive tuning approach. Simulations of two design examples,a 10 MHz third order elliptic low pass filter and a 15 MHz second order band pass filter,reveal that independeent tuning of the controlling voltage of the integrator can obtain better pass band characteristics.
Keywords integrator,tuning,integrated filters

The Effect of Pulse Electomagnetic Fields on Mouse Blood Cells
Zhong Lisheng,Xu Xiaozhou,Xu Chuanxiang
(Xi'an Jiaotong University,710049,Xi'an)
[return]

Abstract In this paper the effect of pulse electromagnetic fields on the mouse blood cell count and cell charging has been studied. It was found that the count of mouse leucocyte and the rate of erythrocyte electrophoresis were obviously reduced under specified pulse electromagnetic fields. Themechanism of the electromagnetic field effect has been discussed by establishing an equivalent dielectric model.
Keywords electromagnetic fields,blood cell count,cell electrophoresis

Network Solution of Leakage Magnetic FieldDistributionof Three-Phase Transformers
Fan Shuwei,Wang Gouliang
(Xi'an Jiaotong University,710049,Xi'an)
Fang ZhiqiangZhang Xingzhi
(Xi'an Power Transformer Factory)
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Abstract A new electromagnetic analysis program in whichthe reluctance model and equivalent magnetic network model are set up to obtainvarious parameters of the equivalent magnetic network is developed based on theequivalent magnetic network method (EMNM). Furthermore the method of forming node potential equations automatically with a computer is introduced. The leakage magnetic distribution curves for power transformers are solved and presented,and then the key parameter£­leakage reluctance which indicates the power transformer leakage magnetic filed is calculated with the energy method. The results are in good agreement with experimental data,which shows the validity of EMNM for power transformer leakage field analysis.
Keywords magnetic network,transformer,leakage field

Study and Application of Fuzzy Cluster Neural Network Based on Wavelet Packets and Its Application
Zhao Jiyuan,He Zhengjia,Meng Qingfeng,Lu Bingheng
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract This paper advances a new approach based on wavelet packets in tandem with the fuzzy cluster neural network. Wavelet packets decompose stationary or nonstationary signals into different bands at different levels. Fuzzy cluster processes the uncertainty problem,and MAXNET realizes selforganizing classification. The approach integrates the advantages of wavelet packets and fuzzy cluster with MAXNET,and therefore it can process uncertainty problems of stationary or nonstationary signals and carry out adaptive pattern recognition and self-organization classification. The network was use to analyse for an example,and the results indicate that it is a useful and effective intelligent classification in the field of fault diagnosis.
Keywords wavelet packets,fuzzy cluster,neural network,signal processing,fault diagnosis

A Prediction Model for Two Body Wear Process
Liu Fengbi,Xie Youbai
(Xi'an Jiaotong University,710049,Xi'an)
[return]

Abstract Based on the plastic hypothesis a mathematical model is given for predicting the wear and the change of roughnesses of two nominal flat surfaces sliding against each other.Main results obtained are as follows:(1)The roughness and the linear wear of any pointion the surfaces vary not only with rubbing distance or time but also with its position the surfaces in the relative moving direction.(2)The contours of the surfaces tend to be of specific shapes.(3)Volume loss is approximately proportional the rubbing distance for both surfaces.
Keywords wear,surfaces roughness,probabilty distribution

The Processing of Balancing Plane Correlationon Multi-Plane Balancing
Wang Xiaosheng,Qu Liangsheng
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract In this paper we discussed the problem of balancing plane correlation on multi?plane balancing and advanced a method to solvethe problem which is based on truncated singular value decomposition technology (TSVD). Compared with existing method,it was found that the new method has a better adaptive and an acceptable calculating efficiency. The result of applying it to balancing is good.
Keywords rotor balancing,collineation (correlation),singular value decomposition

Study on the Controlling Mechanism for the Anti-Drifting Welding Roller Bed
Shen Fenggang,Xue Jin
(Xi'an Jiaotong University,710049,Xi'an)
[return]

Abstract One type of adjusting methods for the anti?drifting of the cylinder is analysed in the paper,based on the basic theory of theaxial drifting of the cylider on a welding roller bed. It is shown that the spiral ratio of the cylinder axial motion is equal to the mean value of the tangent of the spiral angle between the cylinder and rollers,and if adjusting the position of a driven roller properly,the relative position between the cylinder and the roller will be changed so that an additional spiral angle will be produced for the relative axial motion of the cylinder to be controlled effectively. At the same time,a nonlinear control method with displacement and velocity negative feedback is presented. The system stability is analysed with the phase plane method,and the results of analysis are in agreement with those obtained by the model experiment. Therefore it is applicable to control system of antidrifting welding roller bed.
Keywords welding roller bed,axial motion,adjusting mechanism,nonlinear control

Computer Simulation of Vibroimpact Absorbers
Li Wei,Chen Tianning,Hu Xuanli,Huang Xieqing
(Xi'an Jiaotong University,710049,Xi'an)
[return]

Abstract The mechanical model of discrete element method(DEM) for vibroimpact absorbers was developed by using the Hertz's contact theory,and computer simulation was made by the mothod of DEM. The result of simulation was in agreement with that of the experiment. The effect of the parameter variation of vibroimpact absorbers on the performance of vibroimpact absorbing was then studied to provide theoretical principles for guiding the design of vibroimpact absorbers.
Keywords vibroimpact,absorber,DEM,computer simulation

The Effects of Thrust Bearing on Lateral Vibration of a Single-Mass Rotor
Chen Wei,Zhu Jun
(Xi'an Jiaotong University,710049,Xi'an)
[return]

Abstract Due to the lateral vibration of the rotor,a group of dynamic reacting forces and moments in the thrust bearing set in a systemwould couple with lateral vibration of the rotor,and therefore the vibration state of the rotor could be changed by these forces and moments of thrust bearing. To investigate the coupling effects of the thrust bearing on lateral vibrationof rotor,the governing equation in which the dynamic performances of the thrust bearing was taken into account was presented. The effect of the thrust bearing on the system damping of defferent rotors,the effect of axial clearence of the thrust bearing and the effect of the thrust bearing on the vibration state of rotor systems with different journal bearing were analyzed respectively. The results show that the effect of thrust bearing on lateral vibration state of the rotor depends on some factors,such as the shape of rotor and journal bearing,etc..
Keywords thrust bearing,rotor dynamics,lateral vibration

Influence of the Second Surface Metallurgy of Metallic Materials on Vacuum Breakdown Behaviours
Yang Zhimao,Ding Bingjun,Wang Xiaotian
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract The influence of surface second metallurgy and microstruture of surface melt layer on vacuum breakdown is investigated. In this paper,the dielectric strength of CuCr50,CuCr1,pure Cu and Cu50CrWC was measured. Experimental results show that the vacuum breakdown occurs first on the Cr particles. The arc conditioning is the process of second metallugy on the surface of contacts. The addition of WC to CuCr alloys increases the dielectric strength of Cr particles. The relation of hardness and dielectric strength is also discussed.
Keywords vacuum breakdown,microstructure,metallic materials

Formation Mechanism of Spherical PyrolyticCarbon in Process of Rapid CVD
Luo Ruiying,Jin Zhihao (
Xi'an Jiaotong University,710049,Xi'an)
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Abstract Formation mechanism of spherical pyrolytic carbon was discussed in the process of rapid chemical vapour deposition. It has been found experimentally that at deposition temperature 950 ¡æ,and furnace pressure 6.6 KPa,deposition gas flow is smaller than 0.1 m3/h,and pyrolytic carbon is of layered structure. but when deposition gas flow rate is0.4 ¡«0.8 m3/h,pyrolytic carbon is spherical£®The change in shape of the growth features with the changing technological of condition is due to changes in superª²saturation of carbon deposited before its deposition on the substrate.
Keywords rapid CVD,spherical pyrolytic carbon,formation mechanism

Application of COD Criterion to Steel 40CrNiMo Elastic Plastic Fracture Under Mixed Mode I+II Loading
Sha Jiangbo,Deng Zengjie,Zhou Huijiu
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract Based on the blunting model proposed by Rice,the crack opening displacement (COD) b,the crack tip opening displacement(CTOD) bt and the crack tip slipping displacement(CTSD) bs  under mixed I+II mode loading were defined,where(CTOD) bt and(CTSD) bs are the mode I and mode II components of(COD)b respectively. The b parameter was used to analyse the behavior of mixed I+II elasticª²plastic fracture of 40CrNiMo steel,and the relationships between b and J-integral for different mixed ratios were also discussed. The results show that: 1) the initiation of bi of 40CrNiMo decreases with an increasing of mode II component,and the bi of pure mode I loading is 2.5 times of bi of pure mode ¢òloading ; 2) the b,bt,bs and J-integral for different mixed ratios satisfy the linear relations.
Keywords mixed mode loading,COD,criterion elasticª²plastic fracture,J-integral

Relation between ¦Ã-¦Å Martensite Transformation Temperature and Composition in Fe-Mn-Si-Cr-NiSystem Shape Memory Alloys
Li Chenglao,Liang Gongying,Jin Zhihao
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract The empirical expressions for the relationship between the r-f martensite transformation temperatures M,£Á,the hysteresis (A£­M) and the com positions of the alloys have been obtained by using the multipe linear regression method based on existing experimental data in Fe-Mn-Si and Fe-Mn-Si- Cr-Ni systems of shape memory alloys. It has been demonstrated that addition of Mn,Cr and Ni elements tends to lower the martensite transformation temperatures M and £Á,but Si element tends to increase them remarkably,which agrees quite well with the previous result by Schramm,who proposed that Mn,Cr and Ni elements increase the stacking fault energy of the alloys while Si element decreases it. Regression analysisalso indicates that the transformation hysteresis increases with increasing the Cr and Si concentration in Fe-Mn-Si-Cr- Ni system shape memory alloy. The above mentioned result is useful for the composition designing of this type of alloy.
Keywords shape memory alloy,martensite transformation,phase transformation driving force

Study of Surface Remelting Alloying and Cladding of Aluminium Alloy by Laser
Zhao Wenzhen
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract Surface remelting,surface alloying,and surface cladding are 3 essential processes in the surface modification of aluminium alloy by laser. They are distinctive,but there are some relations between each other,too. Their micros- tructures and hardening effects are investigated and contrasted experimentally. The study provides guidance for the application of surface strengthening processes of aluminium alloy by laser.
Keywords aluminium alloy,remelting,alloying,cladding

R-Curve(Crack Resistance) Behaviour of Pressureless Sintering Si3N4
Wang Hongjie,Wang Yonglan,Jin Zhihao,Zhou Huijiu
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract ª«R-curve(crack resistance) behaviour of three kinds of Si3N4 materials was studied using the combination of the indentation crack size with indentation strength method. The results show that the rising R-curve of the material containing Y2O3 and Al3O4(No.1) is more obvious than the material containing ZrO2(No.2),and the R-curve of the material containing AlN(No.3) varies the least . Combined the fracture surface analysis,we find that the R-curve of the materi al is closely related to their microstructure.
Keywords silicon nitride,presureless sintering,R-curve

Microstructural Analysis of the Weld Joints in 9Cr-1Mo-V-Nb Steel
Guo Dazhan,Li FenlanZhu Ruihua
(Xi'an Jiaotong University,710049,Xi'an)
Tong Zheng
(Dongfang Boiler Works)
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Abstract This paper analyses the microstructure of the weld joints formed by combining 9Cr-1Mo-V-Nb with several common heatª²resistant steel. The experimental results indicate that the mechanical properties of the tested weld joints are good. The microstructure of the weld zone of all joints after tempering is of tempered martensite. It is similar to the microstructure of 9Cr-1Mo-V-Nb steel normalized at 1040 ¡æ and tempered at 780 ¡æ,but the grains are bigger. The microstructure of the superheat zone of the weld joints formed in 9Cr-1Mo-V-Nb steel is tempered martensite with a little ¦Äferrite. Compared with the weld joints formed in 9Cr-1Mo-V-Nb steel,the crystalline grains of the superheat zone of weld joints formed by combining 9Cr-1Mo-V-Nb with low alloy steel are bigger,and carbide coarsening and stacking are more apparent.
Keywords heatª²resistant steel,weld joint,microstructure

Micro and Macro Studies on Creep-Fatigue Properties of 317 Stainless Steel
Wang Shiwen,Shen Yapeng
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract The micro and macro behavior of 317 stainless steel (317SS) under creep and fatigue load spectrum is studied in this paper. Test results show that early initiation and late propagation of creep voids are the main factors leading to the fracture of structures.
Keywords creep,fatigue,micromechanism

Global Attractor and Dimensional Estimate for the Coupled Fitz-Hugh-Nagumo Systems
Wu Jianhua
(Xi' an Jiaotong University,710049,Xi' an)
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Abstract The longtime behavior for the coupled Fitz?Hugh?Nagumo systems is considered in the paper. By use of Green's formula and embedding theorem,the paper first proves the cxistence of the global attractor for the coupled FHN model; and then by use of Sobolev-Limb-Thirring inequalities and calculation of the trace for the linearized operator,the paper also gives its dimensional estimate. The longtime behavior for the coupled FHN model has not been studied before,and the restriction of ¡°invariant region¡± imposed by some authors is removed in the proof.
Keywords coupled FHN model,global attractor,dimensional estimate,Green's formula

A New Continuation Method for Solving
MonotoneVariational Inequalities
Liang Ximing,Peng Jigen
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract In this paper a new continuation method for monotone variational inequalities with the general nonempty closed convex set is presented. It is proved that the convergence of the algorithm is equivalent to the solvability of the variational inequality,and the accumulation point of the trajectory generated by the proposed algorithm is not only the solution but also the least twoª²norm solution of the variational inequality.
Keywords variational inequality,continuation method,convergence

An Effective Nonlinear Galerkin Scheme
Hou Yanren,Li Kaitai
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract Based on Marion&Temam type of nonlinear Galerkin method,a kind of full discrete form of improved nonlinear Galerkin method is studied.By theoretical demonstration¡¡and numercal examination,we in tend to indicate that it is a stable and high performance scheme. Keywords Navier-Stokes equations,nonlinear Galerkin method,Fourier method Galerkin Schemes and Their Analyses for the Problem of Natural Convection in an Annular Cavity Yang Xiaozhong (Xi'an Jiaotong University,710049,Xi'an) Abstract Four fully discrete Galerkin FEM schemes are established for a Boussinesq equation of stream function which governs the problem of natural convection in annular cavity. Under some conditions,stability and convergence of these schemes are analyzed,and error estimation is presented.
Keywords Boussinesq equations of stream function,fully Galerkin discrete scheme,stablity,convergence

Galerkin Schemes and Their Analyses for the Problem of Natural Convection in an Annular Cavity
Yang Xiaozhong
(Xi'an Jiaotong University,710049,Xi'an)
[return]

Abstract Four fully discrete Galerkin FEM schemes are established for a Boussinesq equation of stream function which governs the problem of natural convection in annular cavity. Under some conditions,stability and convergence of these schemes are analyzed,and error estimation is presented.
Keywords Boussinesq equations of stream function,fully Galerkin discrete scheme,stablity,convergence

On the Convergence of an Ergodic Iteration for the Solution to Monotone Mappings Equation
Zhang Zhuosheng,Liu Feng
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract In this paper an ergodic iteration scheme is considered to find zeros of monotone mappings. The global weak convergence theorems are obtained for the iteration scheme of the monotone mappings,which are bounded and satisfy a linear growth condition. These results have been directly applied to pseudoª²contractive operators.
Keywords monotone mapping,Hilbert space,ergodic iteration scheme

Preconditioning of Strictly Diagonally
Dominant Symmetric Definite Matrix
Xiang Shuhuang
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract Much interest has been shown in the use of incomplete factorization of matrices in conjugation with applications of the generalized conjugate gradient method for approximate solutions to large sparse systems of linear equations. This paper presents a modified incomplete factorization for real symmetric positive definite strictly diagonally dominant matrix,M-matrix,and H-matrix (MSSOR method),and gives estimations of the condition number of the preconditioned matrices.
Keywords conjugate gradient method,preconditioning,condition number,H-matrix

Extraordinary Hall Effect for Dilute Magnetic Alloys
Tian Dongping
(Xi'an Jaotong University,710049,Xi'an)
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Abstract The extraordinary Hall effect due to the skew scattering is the characteristic of electrons in dilute magnetic alloys. An extended single impurity infinite-U(Intra-atomic coulomb interaction)Anderson Model was used,and a first- order field approximation was performed for a small applied magnetic field. Within the approximation the extraordinary Hall coefficient was calculated using the non? crossing approximation at the low temperature. The numerical results are in qualitative agreement with the experimental results,which account for the main features of the Hall effect in dilute magnetic alloys.
Keywords Hall effect,scattering amplitude,transport coefficient

The Analysis of Internal Resistance and External Force on Technological Innovation in Enterprises
An Liren,Xi Youmin
(Xi'an Jiaotong University,710049,Xi'an)
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Abstract The factors of internal resisitance to technolo gical innovation in enterprises are grouped under three heads: R & D,risk and ¡°inertia¡±.Based on this viewpoint ,the model of internal resistance to technol ogical innovation in enterprises is structured,and the form and the effect of t he three factors are discussed using the model. Then the external force on techn ological innovation in enterprises is analysed with the focus on the market envi ronment,policy and law environment,and technological enviroment.
Keywords technological innovation of enterprise,sinternal resistance,external force

Ninlinear Adaptive Filtering in Spread Spectri Communications
[return]

Li Guorong,Yan Hongsen,Zhu Shihua
(Xi'an Jaotong University,710049,Xi'an)