By truncating the Painleve expansion at the constant level term,the Hirota bilinear form is obtainedfor a (3+1)-dimensional variable-coefficient Kadomtsev-Petviashvili equation.Based on its bilinear form,solitary-wave...By truncating the Painleve expansion at the constant level term,the Hirota bilinear form is obtainedfor a (3+1)-dimensional variable-coefficient Kadomtsev-Petviashvili equation.Based on its bilinear form,solitary-wavesolutions are constructed via the ε-expansion method and the corresponding graphical analysis is given.Furthermore,the exact solution in the Wronskian form is presented and proved by direct substitution into the bilinear equation.展开更多
Weak signal detection based on stochastic resonance （SR） can hardly succeed when noise intensity exceeds the optimal value of SR. This paper explores a novel parallel bistable SR array mechanism by decomposed multi-...Weak signal detection based on stochastic resonance （SR） can hardly succeed when noise intensity exceeds the optimal value of SR. This paper explores a novel parallel bistable SR array mechanism by decomposed multi-scale noises from input signal. A smoother output with lower noise is obtained from the combination of colored noise SR ellect and parallel bistable SR array. The influence of noise intensity and array size on the SR effect and output noise intensity is analyzed through numerical simu- lation. A signal detection method based on the new SR mechanism and normalized scale transform is proposed for the case of heavy background noise. Simulation is conducted to confirm the effectiveness of parameter tuning and amplitude tuning of normalized scale transform on the proposed SR model. The proposed method has three advantages： the input noise intensity of each unit is reduced by wavelet decomposition; the output noise level decreases due to array ensemble average; the SR effect of each unit is optimized by normalized scale transform for high frequency signal. Experiment on bearing inner and outer race fault diagnosis has verified the effectiveness and advantages of the proposed SR model in comparison with traditional SR method and kurlogram.展开更多
Microfluidic droplets have emerged as novel platforms for chemical and biological applications. Manipulation of droplets has thus attracted increasing attention. Different from solid particles, deformable droplets can...Microfluidic droplets have emerged as novel platforms for chemical and biological applications. Manipulation of droplets has thus attracted increasing attention. Different from solid particles, deformable droplets cannot be efficiently controlled by inertia-driven approaches. Here, we report a study on the lateral migration of dual droplet trains in a double spiral microchannel at low Reynolds numbers. The dominant driving mechanism is elucidated as wall effect originated from the droplet deformation. Three types of migration modes are observed with varying Reynolds numbers and the size-dependent mode is intensively investigated. We obtain empirical formulas by relating the migration to Reynolds numbers and droplet sizes. The effect of droplet deformability on the migration and the detailed migration behavior along the double spiral channel are discussed. Numerical simulations are also performed and yielded in qualitative agreement with the experiments. could be a promising alternative to existing inertia-driven approaches bio-particles. This proposed low Re approach based on lateral migration especially concerning deformable entities and susceptible展开更多
1 Introduction Although partial differential equations that govern the motion of solitons are nonlinear, many of them can be put into the bilinear form. Hirota, in 1971, developed an ingenious method to obtain exact ...1 Introduction Although partial differential equations that govern the motion of solitons are nonlinear, many of them can be put into the bilinear form. Hirota, in 1971, developed an ingenious method to obtain exact solutions to nonlinear partial differential equations in the soliton theory, such as the KdV equation, the Boussinesq equation and the KP equation （see [1-2]）.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.60772023the Open Fund of the State Key Laboratory of Software Development Environment under Grant No.BUAA-SKLSDE-09KF-04+1 种基金Beijing University of Aeronautics and Astronautics,by the National Basic Research Program of China (973 Program) under Grant No.2005CB321901the Specialized Research Fund for the Doctoral Program of Higher Education under Grant Nos.20060006024 and 200800130006,the Ministry of Education
文摘By truncating the Painleve expansion at the constant level term,the Hirota bilinear form is obtainedfor a (3+1)-dimensional variable-coefficient Kadomtsev-Petviashvili equation.Based on its bilinear form,solitary-wavesolutions are constructed via the ε-expansion method and the corresponding graphical analysis is given.Furthermore,the exact solution in the Wronskian form is presented and proved by direct substitution into the bilinear equation.
基金supported by the National Natural Science Foundation of China (Grant Nos. 5107539, 51105366 and 51205401)the Research Project of National University of Defense Technology (Grant No. JC12-03-02)
文摘Weak signal detection based on stochastic resonance （SR） can hardly succeed when noise intensity exceeds the optimal value of SR. This paper explores a novel parallel bistable SR array mechanism by decomposed multi-scale noises from input signal. A smoother output with lower noise is obtained from the combination of colored noise SR ellect and parallel bistable SR array. The influence of noise intensity and array size on the SR effect and output noise intensity is analyzed through numerical simu- lation. A signal detection method based on the new SR mechanism and normalized scale transform is proposed for the case of heavy background noise. Simulation is conducted to confirm the effectiveness of parameter tuning and amplitude tuning of normalized scale transform on the proposed SR model. The proposed method has three advantages： the input noise intensity of each unit is reduced by wavelet decomposition; the output noise level decreases due to array ensemble average; the SR effect of each unit is optimized by normalized scale transform for high frequency signal. Experiment on bearing inner and outer race fault diagnosis has verified the effectiveness and advantages of the proposed SR model in comparison with traditional SR method and kurlogram.
基金supported by the National Natural Science Foundation of China(Grant Nos.11572334,11272321 and 11402274)
文摘Microfluidic droplets have emerged as novel platforms for chemical and biological applications. Manipulation of droplets has thus attracted increasing attention. Different from solid particles, deformable droplets cannot be efficiently controlled by inertia-driven approaches. Here, we report a study on the lateral migration of dual droplet trains in a double spiral microchannel at low Reynolds numbers. The dominant driving mechanism is elucidated as wall effect originated from the droplet deformation. Three types of migration modes are observed with varying Reynolds numbers and the size-dependent mode is intensively investigated. We obtain empirical formulas by relating the migration to Reynolds numbers and droplet sizes. The effect of droplet deformability on the migration and the detailed migration behavior along the double spiral channel are discussed. Numerical simulations are also performed and yielded in qualitative agreement with the experiments. could be a promising alternative to existing inertia-driven approaches bio-particles. This proposed low Re approach based on lateral migration especially concerning deformable entities and susceptible
基金Project supported by the State Administration of Foreign Experts Affairs of Chinathe National Natural Science Foundation of China (Nos. 10831003,61072147,11071159)+2 种基金the Shanghai Municipal Natural Science Foundation (No. 09ZR1410800)the Shanghai Leading Academic Discipline Project (No.J50101)TUBITAK (the Scientific and Technological Research Council of Turkey) for its financial support and grant for the research entitled "Integrable Systems and Soliton Theory" at University of South Florida
文摘1 Introduction Although partial differential equations that govern the motion of solitons are nonlinear, many of them can be put into the bilinear form. Hirota, in 1971, developed an ingenious method to obtain exact solutions to nonlinear partial differential equations in the soliton theory, such as the KdV equation, the Boussinesq equation and the KP equation （see [1-2]）.
