Micro-pore is a very common material defect. In the present paper, the temperature fields of medium carbon steel joints with and without micro-pore defect during linear friction welding （LFW） were investigated by us...Micro-pore is a very common material defect. In the present paper, the temperature fields of medium carbon steel joints with and without micro-pore defect during linear friction welding （LFW） were investigated by using finite element method. The effect of micro-pore defect on the axial shortening of joints during LFW was examined. The x- and y-direction displacements of micro-pore during the LFW process were also studied. In addition, the shape of micro-pore after LFW was observed. The heat conducted from the weld inteace to the specimen interior. The fluctuation range of the temperature curves for the joint with micro-pore is larger than that without micro-pore. Position of micro-pore changes with the change of the friction time. The circular shape of micro-pore becomes oval after welding.展开更多
To investigate a novel macro and micro driven linear piezoelectric motor composed of an ultrasonic motor with macro movement and a piezoelectric actuator with micro movement,a digital signal processing(DSP)based macro...To investigate a novel macro and micro driven linear piezoelectric motor composed of an ultrasonic motor with macro movement and a piezoelectric actuator with micro movement,a digital signal processing(DSP)based macro and micro power supply is designed,which fits the new linear piezoelectric motor.The power supply comprises a control circuit,a voltage conversion circuit,an amplifier circuit,a half-bridge module,an optical isolatorsdrive circuit,etc,where the DSP of TMS320F28335 is used as the controller.When the linear piezoelectric motor working in a macro driven state,the power supply outputs alternating currents with high frequency and high voltage,which drives the linear piezoelectric motor dynamically at an ultrasonic frequency;while working in the micro driven state,the power supply outputs direct currents with high voltage,which drives the linear piezoelectric motor in micro driven statically.Here a prototype of the macro-micro power supply is designed.After a series of experiments on the power supply with and without loads,the results show that the power supply can drive and control the macro micro driven linear piezoelectric motor,and realizes quick and seamless switch between macro and micro drive.In addition,the power supply can drive and control the ultrasonic motor or piezoelectric ceramic micro actuator individually.The power supply achieves the multiple parameters of output signals adjustable simultaneously and exhibits good control characteristics.展开更多
The non-linear Fokker-Planck equation arises in describing the evolution of stochastic system, which is a variant of the Boltzmann equation modeling the evolution of the random system with Brownian motion, where the c...The non-linear Fokker-Planck equation arises in describing the evolution of stochastic system, which is a variant of the Boltzmann equation modeling the evolution of the random system with Brownian motion, where the collision term is replaced by a drift-diffusion operator. This model conserves mass, momentum and energy;the dissipation is much weaker than that in a simplified model we considered before which conserved only mass, thus more difficult to analyze. The macro-micro decomposition of the solution around the local Maxwellian introduced by T.-P. Liu, T. Yang and S.-H. Yu for Boltzmann equation is used, to reformulate the model into a fluid-type system incorporate viscosity and heat diffusion terms, coupled with an equation of the microscopic part. The viscosity and heat diffusion terms can give dissipative mechanism for the analysis of the model.展开更多
Deformable micro-continua of highly localized nature are found to exactly exhibit all quantum effects commonly known for quantum entities at microscopic scale.At every instant,the spatial configuration of each such mi...Deformable micro-continua of highly localized nature are found to exactly exhibit all quantum effects commonly known for quantum entities at microscopic scale.At every instant,the spatial configuration of each such micro-continuum is prescribed by four spatial distributions of the mass,the velocity,the internal stress,and the intrinsic angular momentum.The deformability features of such micro-continua in response to all configuration changes are identified with a constitutive equation that specifies how the internal stress responds to the mass density field.It is shown that these microcontinua are endowed with the following unique response features:(i)the coupled system of the nonlinear field equations governing their dynamic responses to any given force and torque fields is exactly reducible to a linear dynamic equation governing a complex field variable;(ii)this fundamental dynamic equation and this complex field variable are just the Schrodinger equation and the complex wave function in quantum theory;and,accordingly,(iii)the latter two and all quantum effects known for quantum entities are in a natural and unified manner incorporated as the inherent response features of the micro-continua discovered,thus following objective and deterministic response patterns for quantum entities,in which the physical origins and meanings of the wave function and the Schrodinger equation become self-evident and,in particular,any probabilistic indeterminacy becomes irrelevant.展开更多
A Mathemataical model for a modified micro- cylinder electrode in which polyphenol oxidase ( PPO) occurs for all values of the concentration of catechol and o-quinone is analysed. This model is based on system of reac...A Mathemataical model for a modified micro- cylinder electrode in which polyphenol oxidase ( PPO) occurs for all values of the concentration of catechol and o-quinone is analysed. This model is based on system of reaction-diffusion Equations containing a non-linear term related to Michaelis Menten kinetics of the enzymatic reaction. Here a new analytical technique Homotopy Perturbation Method is used to solve the system of non-linear differential Equations that describe the diffusion coupled with a Michaelis-Menten kinetics law. Here we report an analytical expressions pretaining to the concentration of catechol and o-quinone and corresponding current in terms of dimensionless reaction-diffusion parameters in closed form. An excellent agreement with available limiting case is noticed.展开更多
基金The authors would like to appreeiate the National Natural Science Foundation of China （51005180）, the Fok Ying-Tong Educalion Fuundalion for Young Teachers in the Higher Education Institutions of China （131052） , the Fundamental Research Fund of NPU（JC201233） , and the 111 Project of China （B08040）.
文摘Micro-pore is a very common material defect. In the present paper, the temperature fields of medium carbon steel joints with and without micro-pore defect during linear friction welding （LFW） were investigated by using finite element method. The effect of micro-pore defect on the axial shortening of joints during LFW was examined. The x- and y-direction displacements of micro-pore during the LFW process were also studied. In addition, the shape of micro-pore after LFW was observed. The heat conducted from the weld inteace to the specimen interior. The fluctuation range of the temperature curves for the joint with micro-pore is larger than that without micro-pore. Position of micro-pore changes with the change of the friction time. The circular shape of micro-pore becomes oval after welding.
基金supported by the National Natural Science Foundation of China(No.51177053)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.2012CXZD0016)+1 种基金the Key Project of Department of Education of Guangdong Province(No.20124404110003)Guangzhou Science and Technology Project(No.201510010227)
文摘To investigate a novel macro and micro driven linear piezoelectric motor composed of an ultrasonic motor with macro movement and a piezoelectric actuator with micro movement,a digital signal processing(DSP)based macro and micro power supply is designed,which fits the new linear piezoelectric motor.The power supply comprises a control circuit,a voltage conversion circuit,an amplifier circuit,a half-bridge module,an optical isolatorsdrive circuit,etc,where the DSP of TMS320F28335 is used as the controller.When the linear piezoelectric motor working in a macro driven state,the power supply outputs alternating currents with high frequency and high voltage,which drives the linear piezoelectric motor dynamically at an ultrasonic frequency;while working in the micro driven state,the power supply outputs direct currents with high voltage,which drives the linear piezoelectric motor in micro driven statically.Here a prototype of the macro-micro power supply is designed.After a series of experiments on the power supply with and without loads,the results show that the power supply can drive and control the macro micro driven linear piezoelectric motor,and realizes quick and seamless switch between macro and micro drive.In addition,the power supply can drive and control the ultrasonic motor or piezoelectric ceramic micro actuator individually.The power supply achieves the multiple parameters of output signals adjustable simultaneously and exhibits good control characteristics.
文摘The non-linear Fokker-Planck equation arises in describing the evolution of stochastic system, which is a variant of the Boltzmann equation modeling the evolution of the random system with Brownian motion, where the collision term is replaced by a drift-diffusion operator. This model conserves mass, momentum and energy;the dissipation is much weaker than that in a simplified model we considered before which conserved only mass, thus more difficult to analyze. The macro-micro decomposition of the solution around the local Maxwellian introduced by T.-P. Liu, T. Yang and S.-H. Yu for Boltzmann equation is used, to reformulate the model into a fluid-type system incorporate viscosity and heat diffusion terms, coupled with an equation of the microscopic part. The viscosity and heat diffusion terms can give dissipative mechanism for the analysis of the model.
基金Project supported by the National Natural Science Foundation of China(No.11372172)
文摘Deformable micro-continua of highly localized nature are found to exactly exhibit all quantum effects commonly known for quantum entities at microscopic scale.At every instant,the spatial configuration of each such micro-continuum is prescribed by four spatial distributions of the mass,the velocity,the internal stress,and the intrinsic angular momentum.The deformability features of such micro-continua in response to all configuration changes are identified with a constitutive equation that specifies how the internal stress responds to the mass density field.It is shown that these microcontinua are endowed with the following unique response features:(i)the coupled system of the nonlinear field equations governing their dynamic responses to any given force and torque fields is exactly reducible to a linear dynamic equation governing a complex field variable;(ii)this fundamental dynamic equation and this complex field variable are just the Schrodinger equation and the complex wave function in quantum theory;and,accordingly,(iii)the latter two and all quantum effects known for quantum entities are in a natural and unified manner incorporated as the inherent response features of the micro-continua discovered,thus following objective and deterministic response patterns for quantum entities,in which the physical origins and meanings of the wave function and the Schrodinger equation become self-evident and,in particular,any probabilistic indeterminacy becomes irrelevant.
文摘A Mathemataical model for a modified micro- cylinder electrode in which polyphenol oxidase ( PPO) occurs for all values of the concentration of catechol and o-quinone is analysed. This model is based on system of reaction-diffusion Equations containing a non-linear term related to Michaelis Menten kinetics of the enzymatic reaction. Here a new analytical technique Homotopy Perturbation Method is used to solve the system of non-linear differential Equations that describe the diffusion coupled with a Michaelis-Menten kinetics law. Here we report an analytical expressions pretaining to the concentration of catechol and o-quinone and corresponding current in terms of dimensionless reaction-diffusion parameters in closed form. An excellent agreement with available limiting case is noticed.
