Objective To compare the efficacy of treating obese patients with abnormity of lipids and serum leptin by dilatational wave or continuous wave of electroacupuncture combined with thunder-fire moxibustion in order to p...Objective To compare the efficacy of treating obese patients with abnormity of lipids and serum leptin by dilatational wave or continuous wave of electroacupuncture combined with thunder-fire moxibustion in order to provide a clinical basis for selecting wave types of electroacupuncture for different patterns of obesity. Methods Sixty obese patients with abnormal lipids and serum leptin were randomly divided into a dilatational wave group and a continuous wave group via random number table, with 30 cases in each group. They were divided by TCM differentiation into three types： stomachintestine excessive heat, weakness of the spleen-stomach and spleen-kidney yang deficiency, treated by electroacupuncture on Tianshu （天枢 ST 25）, Daheng （大横 SP 15）, Zusanli （足三里ST 36）, Shangjuxu （上巨虚 ST 37）, Fanglong （丰隆 ST 40）, Yinlingquan （阴陵泉 SP 9）, Quchi （曲池 LI 11）, Zhigou （支沟 TE 6） and Hegu （合谷 LI 4） along with thunder-fire moxibustion. The frequency of electro-acupuncture in the dilatational wave group and the continuous wave group was 2 Hz/100 Hz and 2 Hz, respectively. Patients in the two groups were treated once a day, six times a week. The treatment lasted for 4 weeks with 3-month follow-up. Body mass and body fat percentage before and after the treatment, as well as during the follow-up, were compared. The effectiveness rates in the two groups were compared, and the efficacy statistics of patients with different TCM patterns in the dilatational wave group were also analyzed. Lipid levels of the patients in two groups before and after the treatment were measured with an automatic biochemical analyzer, and serum leptin levels were detected with flow cytometry system. Results After the treatment, the patients＇ blood lipids, serum leptin levels, body mass and body fat percentage were effectively reduced in the two groups; three months＇ follow-up witnessed continuous decline of obesity indicators （P〈0.01 or P〈0.05）, and patients in the dilatat-ional wave group improved more significantly than those in continuous wave group （P〈0.05 or P〈0.01）. The efficacy in the dilatational wave group was superior to that in the continuous wave group （P〈0.01）. The best efficacy could be found among patients with weakness of the spleen and the stomach in the dilatational wave group. Conclusion Efficacy of treating obese patients with abnormity of lipids and serum leptin by electro-acupuncture combined with thunder-fire moxibustion in the dilatational wave group was significantly better than that of the continuous wave group, and efficacy for obese patients with weakness of the spleen and the stomach was superior to that of those with stomach-intestine excessive heat and spleen-kidney yang deficiency.展开更多
The ultrasonic motor is a sort of new type of micromotor with special structure. By use of piezoelectric converse effect of ceramics, the electrical energy is transformed into mechanical energy. Its operating principl...The ultrasonic motor is a sort of new type of micromotor with special structure. By use of piezoelectric converse effect of ceramics, the electrical energy is transformed into mechanical energy. Its operating principle is quite different from that of the traditional motors. In this paper the equivalent circuits of the ring stator and even the whole motor are proposed after studying the equivalent circuit of piezoelectric vibrator. Then the paper makes detailed analyses of each part of the control system, which has been simplified by the equivalent circuit. The theory in this paper has been proved through experiments.展开更多
Owing to the stochastic behavior of earthquakes and complex crustal structure,wave type and incident direction are uncertain when seismic waves arrive at a structure.In addition,because of the different types of the s...Owing to the stochastic behavior of earthquakes and complex crustal structure,wave type and incident direction are uncertain when seismic waves arrive at a structure.In addition,because of the different types of the structures and terrains,the traveling wave effects have different influences on the dynamic response of the structures.For the tall concrete-faced rockfill dam(CFRD),it is not only built in the complex terrain such as river valley,but also its height has reached 300 m level,which puts forward higher requirements for the seismic safety of the anti-seepage system mainly comprising concrete face slabs,especially the accurate location of the weak area in seism.Considering the limitations of the traditional uniform vibration analysis method,we implemented an efficient dynamic interaction analysis between a tall CFRD and its foundation using a non-uniform wave input method with a viscous-spring artificial boundary and equivalent nodal loads.This method was then applied to investigate the dynamic stress distribution on the concrete face slabs for different seismic wave types and incident directions.The results indicate that dam-foundation interactions behave differently at different wave incident angles,and that the traveling wave effect becomes more evident in valley topography.Seismic wave type and incident direction dramatically influenced stress in the face slab,and the extreme stress values and distribution law will vary under oblique wave incidence.The influence of the incident direction on slab stress was particularly apparent when SH-waves arrived from the left bank.Specifically,the extreme stress values in the face slab increased with an increasing incident angle.Interestingly,the locations of the extreme stress values changed mainly along the axis of the dam,and did not exhibit large changes in height.The seismic safety of CFRDs is therefore lower at higher incident angles from an anti-seepage perspective.Therefore,it is necessary to consider both the seismic wave type and incident direction during seismic capacity evaluations of tall CFRDs.展开更多
The propagation of a Bleustein-Gulyaev （B-G） type wave in a structure consisting of multiple layers and a half-space of porous piezoelectric materials is theoreti- cally studied. The solutions of the problem in term...The propagation of a Bleustein-Gulyaev （B-G） type wave in a structure consisting of multiple layers and a half-space of porous piezoelectric materials is theoreti- cally studied. The solutions of the problem in terms of the mechanical displacements and electric potential functions are obtained for each layer and the half-space. The dispersion equation is obtained for electrically open and shorted boundary conditions by use of the transfer matrix method. A peculiar kind of B-G waves is investigated, which can propagate only in the layer over the half-space. The relationship between the piezoelectric constants and the dielectric constants is found for the existence of a peculiar kind of propagation modes. The numerical results in terms of the phase velocity and the electromechanical coupling factor with different thicknesses of the layer stack are presented.展开更多
In this article, we consider the global existence and decay rates of solutions for the transmission problem of Kirchhoff type wave equations consisting of two physi- cally different types of materials, one component i...In this article, we consider the global existence and decay rates of solutions for the transmission problem of Kirchhoff type wave equations consisting of two physi- cally different types of materials, one component is a Kirchhoff type wave equation with nonlinear time dependent localized dissipation which is effective only on a neighborhood of certain part of the boundary, while the other is a Kirchhoff type wave equation with nonlinear memory.展开更多
Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is u...Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is used to simulate the vibrating-sliding motion of the caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave impacts and the sliding motion on the dynamic response behaviors of caisson breakwaters are investigated and the calculation of relevant system parameters is discussed. It is shown that the dynamic responses of the caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. The amplitude of dynamic response of the caisson is lower under single peak impact excitation than that under double peak impact or shock-damping oscillation impact excitation. Though the displacement of the caisson is large due to sliding, the rotation, the sliding force and the overturning moment of the caisson are significantly reduced.展开更多
Overturning is one of principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. The mass-spring-dashpot model of caisson-foundation system is use...Overturning is one of principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. The mass-spring-dashpot model of caisson-foundation system is used to simulate the vibrating-uplift rocking motion of caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave types and the uplift rocking motion on dynamic response behaviors of caisson breakwaters are investigated. It is shown that the dynamic responses of a caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. Though the rotation of a caisson is larger due to the uplift rocking motion, the displacement, the sliding force and the overturning moment of the caisson are significantly reduced. It provides the theoretical base for the design idea that the uplift rocking motion of caisson is allowed in design.展开更多
The paper studies the asymptotic behavior of solution to the initial boundary value problem for a nonlinear hyperbolic equation of Kirchhoff type It proves the global existence of solution by constructing a stable se...The paper studies the asymptotic behavior of solution to the initial boundary value problem for a nonlinear hyperbolic equation of Kirchhoff type It proves the global existence of solution by constructing a stable set and the energy exponential decayestimate by applying a lemma of V Komornik.展开更多
In this paper, we consider multi-symplectic Fourier pseudospectral method for a high order integrable equation of KdV type, which describes many important physical phenomena. The multi-symplectic structure are constru...In this paper, we consider multi-symplectic Fourier pseudospectral method for a high order integrable equation of KdV type, which describes many important physical phenomena. The multi-symplectic structure are constructed for the equation, and the conservation laws of the continuous equation are presented. The multisymplectic discretization of each formulation is exemplified by the multi-symplectic Fourier pseudospectral scheme. The numerical experiments are given, and the results verify the efficiency of the Fourier pseudospectral method.展开更多
It is difficult to compute far-field waves in a relative large area by using one wave generation model when a large calculation domain is needed because of large dimensions of the waterway and long distance of the req...It is difficult to compute far-field waves in a relative large area by using one wave generation model when a large calculation domain is needed because of large dimensions of the waterway and long distance of the required computing points. Variation of waterway bathymetry and nonlinearity in the far field cannot be included in a ship fixed process either. A coupled method combining a wave generation model and wave propagation model is then used in this paper to simulate the wash waves generated by the passing ship. A NURBS-based higher order panel method is adopted as the stationary wave generation model; a wave spectrum method and Boussinesq-type equation wave model are used as the wave propagation model for the constant water depth condition and variable water depth condition, respectively. The waves calculated by the NURBS-based higher order panel method in the near field are used as the input for the wave spectrum method and the Boussinesq-type equation wave model to obtain the far-field waves. With this approach it is possible to simulate the ship wash waves including the effects of water depth and waterway bathymetry. Parts of the calculated results are validated experimentally, and the agreement is demonstrated. The effects of ship wash waves on the moored ship are discussed by using a diffraction theory method. The results indicate that the prediction of the ship induced waves by coupling models is feasible.展开更多
The celebrated(1+1)-dimensional Korteweg de-Vries(KdV)equation and its(2+1)-dimensional extension,the Kadomtsev-Petviashvili(KP)equation,are two of the most important models in physical science.The KP hierarchy is exp...The celebrated(1+1)-dimensional Korteweg de-Vries(KdV)equation and its(2+1)-dimensional extension,the Kadomtsev-Petviashvili(KP)equation,are two of the most important models in physical science.The KP hierarchy is explicitly written out by means of the linearized operator of the KP equation.A novel(2+1)-dimensional KdV extension,the cKP3-4 equation,is obtained by combining the third member(KP3,the usual KP equation)and the fourth member(KP4)of the KP hierarchy.The integrability of the cKP3-4 equation is guaranteed by the existence of the Lax pair and dual Lax pair.The cKP3-4 system can be bilinearized by using Hirota's bilinear operators after introducing an additional auxiliary variable.Exact solutions of the cKP3-4 equation possess some peculiar and interesting properties which are not valid for the KP3 and KP4 equations.For instance,the soliton molecules and the missing D'Alembert type solutions(the arbitrary travelling waves moving in one direction with a fixed model dependent velocity)including periodic kink molecules,periodic kink-antikink molecules,few-cycle solitons,and envelope solitons exist for the cKP3-4 equation but not for the separated KP3 equation and the KP4 equation.展开更多
Differences in arterial stiffness between the two sides of the carotid arteries were investigated using ultrasonic radiofrequency in 88 patients with type 2 diabetes and 70 controls. The compliance coefficient（CC）, ...Differences in arterial stiffness between the two sides of the carotid arteries were investigated using ultrasonic radiofrequency in 88 patients with type 2 diabetes and 70 controls. The compliance coefficient（CC）, pulse wave velocity（PWV）, intima-media thickness（CIMT） and diameter（CCAD） of the common carotid arteries（CCAs） were measured. The ratio of the left to right CCAs was calculated to provide four indexes： CC ratio, PWV ratio, CIMT ratio and CCAD ratio. In the diabetes group, the PWV on the left side was significantly higher than that on the right side, while the CC on the left side was significantly lower than that on the right side. The bilateral CIMT was thicker and CCAD was wider, the left PWV traveled faster, and the right CC was higher in the diabetes group than in the control group. The PWV ratio between the two groups was significantly different and correlated positively with duration of diabetes and systolic blood pressure（SBP）. The differences between the two sides of CCAs in patients with diabetes suggested that disease duration and SBP were important risk factors for arterial stiffness. Identifying the difference could potentially lead to the much earlier diagnosis of arteriosclerosis.展开更多
The higher order wave equation of KdV type, which describes many important physical phenomena, has been investigated widely in last several decades. In this work, multi- symplectic formulations for the higher order wa...The higher order wave equation of KdV type, which describes many important physical phenomena, has been investigated widely in last several decades. In this work, multi- symplectic formulations for the higher order wave equation of KdV type are presented, and the local conservation laws are shown to correspond to certain well-known Hamiltonian functionals. The multi-symplectic discretization of each formulation is calculated by the multi-symplectic Fourier pseudospectral scheme. Numerical experiments are carried out, which verify the efficiency of the Fourier pseudospectral method.展开更多
A floating type pendulum wave energy converter(FPWEC) with a rotary vane pump as the power take-off system was proposed by Watabe et al.in 1998.They showed that this device had high energy conversion efficiency.In the...A floating type pendulum wave energy converter(FPWEC) with a rotary vane pump as the power take-off system was proposed by Watabe et al.in 1998.They showed that this device had high energy conversion efficiency.In the previous research,the authors conducted 2D wave tank tests in regular waves to evaluate the generating efficiency of FPWEC with a power take-off system composed of pulleys,belts and a generator.As a result,the influence of the electrical load on the generating efficiency was shown.Continuously,the load characteristics of FPWEC are pursued experimentally by using the servo motors to change the damping coefficient in this paper.In a later part of this paper,the motions of the model with the servo motors are compared with that of the case with the same power take-off system as the previous research.From the above experiment,it may be concluded that the maximum primary conversion efficiency is achieved as high as 98%at the optimal load.展开更多
For the Fisher-type wave equation, which has two stable states and one unstable state, it is proved that only in two particular cases, the corresponding travelling wave equation admits a double parameter Lie group, an...For the Fisher-type wave equation, which has two stable states and one unstable state, it is proved that only in two particular cases, the corresponding travelling wave equation admits a double parameter Lie group, and based on a method different to the traditional one, its two independent first integrals are given. It is proved further that in the two integrable cases, the different bounded and non-trivial travelling wave solutions, which are corresponding the invariant manifolds of the corresponding equation under the Lie transformation, can be expressed with elementary functions although they cannot be obtained directly from the two independent first integrals.展开更多
To maintain the calmness of the harbor,rubble mound breakwaters are one of the practical measures to protect sailing and mooring waters.This paper investigates the effect of relocated rubble mound breakwaters on tranq...To maintain the calmness of the harbor,rubble mound breakwaters are one of the practical measures to protect sailing and mooring waters.This paper investigates the effect of relocated rubble mound breakwaters on tranquillity in Busan yacht range and the impact of bridge piers at the entrance of the yacht range based on physical hydraulic modeling using multi-directional random waves.It is obtained that the sufficient tranquillity can be due to securely moored yachts,owing to newly relocated rubble mound breakwaters away from piers.The experimental results also showed the distribution of the energy difference’dependence on various wave directions.The experimental findings are valuable for the design of Busan yacht marina,and are of reference to other port projects.展开更多
Spiral waves have been observed in the biological experiments on rat cortex perfused with drugs which can block inhibitory synapse and switch neuron excitability from type II to type I. To simulate the spiral waves ob...Spiral waves have been observed in the biological experiments on rat cortex perfused with drugs which can block inhibitory synapse and switch neuron excitability from type II to type I. To simulate the spiral waves observed in the experiment, the spatiotemporal patterns are investigated in a network composed of neurons with type I and II excitabilities and excitatory coupling. Spiral waves emerge when the percentage(p) of neurons with type I excitability in the network is at middle levels, which is dependent on the coupling strength. Compared with other spatial patterns which appear at different p values, spiral waves exhibit optimal spatial correlation at a certain spatial frequency, implying the occurrence of spatial coherence resonance-like phenomenon. Some dynamical characteristics of the network such as mean firing frequency and synchronous degree can be well interpreted with distinct properties between type I excitability and type II excitability. The results not only identify dynamics of spiral waves in neuronal networks composed of neurons with different excitabilities, but also are helpful to understanding the emergence of spiral waves observed in the biological experiment.展开更多
基金Supported by Guangxi Natural Science Foundation Project:2010 GXNSFA 013210
文摘Objective To compare the efficacy of treating obese patients with abnormity of lipids and serum leptin by dilatational wave or continuous wave of electroacupuncture combined with thunder-fire moxibustion in order to provide a clinical basis for selecting wave types of electroacupuncture for different patterns of obesity. Methods Sixty obese patients with abnormal lipids and serum leptin were randomly divided into a dilatational wave group and a continuous wave group via random number table, with 30 cases in each group. They were divided by TCM differentiation into three types： stomachintestine excessive heat, weakness of the spleen-stomach and spleen-kidney yang deficiency, treated by electroacupuncture on Tianshu （天枢 ST 25）, Daheng （大横 SP 15）, Zusanli （足三里ST 36）, Shangjuxu （上巨虚 ST 37）, Fanglong （丰隆 ST 40）, Yinlingquan （阴陵泉 SP 9）, Quchi （曲池 LI 11）, Zhigou （支沟 TE 6） and Hegu （合谷 LI 4） along with thunder-fire moxibustion. The frequency of electro-acupuncture in the dilatational wave group and the continuous wave group was 2 Hz/100 Hz and 2 Hz, respectively. Patients in the two groups were treated once a day, six times a week. The treatment lasted for 4 weeks with 3-month follow-up. Body mass and body fat percentage before and after the treatment, as well as during the follow-up, were compared. The effectiveness rates in the two groups were compared, and the efficacy statistics of patients with different TCM patterns in the dilatational wave group were also analyzed. Lipid levels of the patients in two groups before and after the treatment were measured with an automatic biochemical analyzer, and serum leptin levels were detected with flow cytometry system. Results After the treatment, the patients＇ blood lipids, serum leptin levels, body mass and body fat percentage were effectively reduced in the two groups; three months＇ follow-up witnessed continuous decline of obesity indicators （P〈0.01 or P〈0.05）, and patients in the dilatat-ional wave group improved more significantly than those in continuous wave group （P〈0.05 or P〈0.01）. The efficacy in the dilatational wave group was superior to that in the continuous wave group （P〈0.01）. The best efficacy could be found among patients with weakness of the spleen and the stomach in the dilatational wave group. Conclusion Efficacy of treating obese patients with abnormity of lipids and serum leptin by electro-acupuncture combined with thunder-fire moxibustion in the dilatational wave group was significantly better than that of the continuous wave group, and efficacy for obese patients with weakness of the spleen and the stomach was superior to that of those with stomach-intestine excessive heat and spleen-kidney yang deficiency.
文摘The ultrasonic motor is a sort of new type of micromotor with special structure. By use of piezoelectric converse effect of ceramics, the electrical energy is transformed into mechanical energy. Its operating principle is quite different from that of the traditional motors. In this paper the equivalent circuits of the ring stator and even the whole motor are proposed after studying the equivalent circuit of piezoelectric vibrator. Then the paper makes detailed analyses of each part of the control system, which has been simplified by the equivalent circuit. The theory in this paper has been proved through experiments.
基金supported by the National Natural Science Foundation of China(Nos.52192674,U1965206,U2240211)the Fundamental Research Funds for the Central Universities(No.DUT21TD106)。
文摘Owing to the stochastic behavior of earthquakes and complex crustal structure,wave type and incident direction are uncertain when seismic waves arrive at a structure.In addition,because of the different types of the structures and terrains,the traveling wave effects have different influences on the dynamic response of the structures.For the tall concrete-faced rockfill dam(CFRD),it is not only built in the complex terrain such as river valley,but also its height has reached 300 m level,which puts forward higher requirements for the seismic safety of the anti-seepage system mainly comprising concrete face slabs,especially the accurate location of the weak area in seism.Considering the limitations of the traditional uniform vibration analysis method,we implemented an efficient dynamic interaction analysis between a tall CFRD and its foundation using a non-uniform wave input method with a viscous-spring artificial boundary and equivalent nodal loads.This method was then applied to investigate the dynamic stress distribution on the concrete face slabs for different seismic wave types and incident directions.The results indicate that dam-foundation interactions behave differently at different wave incident angles,and that the traveling wave effect becomes more evident in valley topography.Seismic wave type and incident direction dramatically influenced stress in the face slab,and the extreme stress values and distribution law will vary under oblique wave incidence.The influence of the incident direction on slab stress was particularly apparent when SH-waves arrived from the left bank.Specifically,the extreme stress values in the face slab increased with an increasing incident angle.Interestingly,the locations of the extreme stress values changed mainly along the axis of the dam,and did not exhibit large changes in height.The seismic safety of CFRDs is therefore lower at higher incident angles from an anti-seepage perspective.Therefore,it is necessary to consider both the seismic wave type and incident direction during seismic capacity evaluations of tall CFRDs.
基金Project supported by the Council of Scientific and Industrial Research of India(No.09/105(0162)/2008-EMR-I)
文摘The propagation of a Bleustein-Gulyaev （B-G） type wave in a structure consisting of multiple layers and a half-space of porous piezoelectric materials is theoreti- cally studied. The solutions of the problem in terms of the mechanical displacements and electric potential functions are obtained for each layer and the half-space. The dispersion equation is obtained for electrically open and shorted boundary conditions by use of the transfer matrix method. A peculiar kind of B-G waves is investigated, which can propagate only in the layer over the half-space. The relationship between the piezoelectric constants and the dielectric constants is found for the existence of a peculiar kind of propagation modes. The numerical results in terms of the phase velocity and the electromechanical coupling factor with different thicknesses of the layer stack are presented.
文摘In this article, we consider the global existence and decay rates of solutions for the transmission problem of Kirchhoff type wave equations consisting of two physi- cally different types of materials, one component is a Kirchhoff type wave equation with nonlinear time dependent localized dissipation which is effective only on a neighborhood of certain part of the boundary, while the other is a Kirchhoff type wave equation with nonlinear memory.
基金This project was financially supported by the National Natural Science Foundation of China(Grant No.50279027)
文摘Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is used to simulate the vibrating-sliding motion of the caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave impacts and the sliding motion on the dynamic response behaviors of caisson breakwaters are investigated and the calculation of relevant system parameters is discussed. It is shown that the dynamic responses of the caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. The amplitude of dynamic response of the caisson is lower under single peak impact excitation than that under double peak impact or shock-damping oscillation impact excitation. Though the displacement of the caisson is large due to sliding, the rotation, the sliding force and the overturning moment of the caisson are significantly reduced.
基金theNationalNaturalScienceFoundationofChina (No .50 2 790 2 7)andtheScienceFoundationofTianjinMunicipalCommissionofScienceandTechnology (No .0 43 1 1 4 71 1 )
文摘Overturning is one of principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. The mass-spring-dashpot model of caisson-foundation system is used to simulate the vibrating-uplift rocking motion of caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave types and the uplift rocking motion on dynamic response behaviors of caisson breakwaters are investigated. It is shown that the dynamic responses of a caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. Though the rotation of a caisson is larger due to the uplift rocking motion, the displacement, the sliding force and the overturning moment of the caisson are significantly reduced. It provides the theoretical base for the design idea that the uplift rocking motion of caisson is allowed in design.
基金Foundation item： Supported by the National Natural Science Foundation of China（11271336）
文摘The paper studies the asymptotic behavior of solution to the initial boundary value problem for a nonlinear hyperbolic equation of Kirchhoff type It proves the global existence of solution by constructing a stable set and the energy exponential decayestimate by applying a lemma of V Komornik.
文摘In this paper, we consider multi-symplectic Fourier pseudospectral method for a high order integrable equation of KdV type, which describes many important physical phenomena. The multi-symplectic structure are constructed for the equation, and the conservation laws of the continuous equation are presented. The multisymplectic discretization of each formulation is exemplified by the multi-symplectic Fourier pseudospectral scheme. The numerical experiments are given, and the results verify the efficiency of the Fourier pseudospectral method.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.50879066 and 51409201)the Research Fund for the Doctoral Program of Higher Education of China(Grant No.200804970009)
文摘It is difficult to compute far-field waves in a relative large area by using one wave generation model when a large calculation domain is needed because of large dimensions of the waterway and long distance of the required computing points. Variation of waterway bathymetry and nonlinearity in the far field cannot be included in a ship fixed process either. A coupled method combining a wave generation model and wave propagation model is then used in this paper to simulate the wash waves generated by the passing ship. A NURBS-based higher order panel method is adopted as the stationary wave generation model; a wave spectrum method and Boussinesq-type equation wave model are used as the wave propagation model for the constant water depth condition and variable water depth condition, respectively. The waves calculated by the NURBS-based higher order panel method in the near field are used as the input for the wave spectrum method and the Boussinesq-type equation wave model to obtain the far-field waves. With this approach it is possible to simulate the ship wash waves including the effects of water depth and waterway bathymetry. Parts of the calculated results are validated experimentally, and the agreement is demonstrated. The effects of ship wash waves on the moored ship are discussed by using a diffraction theory method. The results indicate that the prediction of the ship induced waves by coupling models is feasible.
基金the National Natural Science Foundation of China(Grant Nos.11975131 and 11435005)and K.C.Wong Magna Fund in Ningbo University.
文摘The celebrated(1+1)-dimensional Korteweg de-Vries(KdV)equation and its(2+1)-dimensional extension,the Kadomtsev-Petviashvili(KP)equation,are two of the most important models in physical science.The KP hierarchy is explicitly written out by means of the linearized operator of the KP equation.A novel(2+1)-dimensional KdV extension,the cKP3-4 equation,is obtained by combining the third member(KP3,the usual KP equation)and the fourth member(KP4)of the KP hierarchy.The integrability of the cKP3-4 equation is guaranteed by the existence of the Lax pair and dual Lax pair.The cKP3-4 system can be bilinearized by using Hirota's bilinear operators after introducing an additional auxiliary variable.Exact solutions of the cKP3-4 equation possess some peculiar and interesting properties which are not valid for the KP3 and KP4 equations.For instance,the soliton molecules and the missing D'Alembert type solutions(the arbitrary travelling waves moving in one direction with a fixed model dependent velocity)including periodic kink molecules,periodic kink-antikink molecules,few-cycle solitons,and envelope solitons exist for the cKP3-4 equation but not for the separated KP3 equation and the KP4 equation.
基金supported by grants from the Shanghai Health and Family Planning Commission Fund of China(No.201440290)Shanghai Science and Technology Committee Fund of China(No.15411969100)Shanghai Jiaotong University Interdisciplinary Projects of Medicine and Engineering,China(No.YG2015MS28)
文摘Differences in arterial stiffness between the two sides of the carotid arteries were investigated using ultrasonic radiofrequency in 88 patients with type 2 diabetes and 70 controls. The compliance coefficient（CC）, pulse wave velocity（PWV）, intima-media thickness（CIMT） and diameter（CCAD） of the common carotid arteries（CCAs） were measured. The ratio of the left to right CCAs was calculated to provide four indexes： CC ratio, PWV ratio, CIMT ratio and CCAD ratio. In the diabetes group, the PWV on the left side was significantly higher than that on the right side, while the CC on the left side was significantly lower than that on the right side. The bilateral CIMT was thicker and CCAD was wider, the left PWV traveled faster, and the right CC was higher in the diabetes group than in the control group. The PWV ratio between the two groups was significantly different and correlated positively with duration of diabetes and systolic blood pressure（SBP）. The differences between the two sides of CCAs in patients with diabetes suggested that disease duration and SBP were important risk factors for arterial stiffness. Identifying the difference could potentially lead to the much earlier diagnosis of arteriosclerosis.
文摘The higher order wave equation of KdV type, which describes many important physical phenomena, has been investigated widely in last several decades. In this work, multi- symplectic formulations for the higher order wave equation of KdV type are presented, and the local conservation laws are shown to correspond to certain well-known Hamiltonian functionals. The multi-symplectic discretization of each formulation is calculated by the multi-symplectic Fourier pseudospectral scheme. Numerical experiments are carried out, which verify the efficiency of the Fourier pseudospectral method.
文摘A floating type pendulum wave energy converter(FPWEC) with a rotary vane pump as the power take-off system was proposed by Watabe et al.in 1998.They showed that this device had high energy conversion efficiency.In the previous research,the authors conducted 2D wave tank tests in regular waves to evaluate the generating efficiency of FPWEC with a power take-off system composed of pulleys,belts and a generator.As a result,the influence of the electrical load on the generating efficiency was shown.Continuously,the load characteristics of FPWEC are pursued experimentally by using the servo motors to change the damping coefficient in this paper.In a later part of this paper,the motions of the model with the servo motors are compared with that of the case with the same power take-off system as the previous research.From the above experiment,it may be concluded that the maximum primary conversion efficiency is achieved as high as 98%at the optimal load.
文摘For the Fisher-type wave equation, which has two stable states and one unstable state, it is proved that only in two particular cases, the corresponding travelling wave equation admits a double parameter Lie group, and based on a method different to the traditional one, its two independent first integrals are given. It is proved further that in the two integrable cases, the different bounded and non-trivial travelling wave solutions, which are corresponding the invariant manifolds of the corresponding equation under the Lie transformation, can be expressed with elementary functions although they cannot be obtained directly from the two independent first integrals.
基金supported for two years by Pusan National University Research Grant BK21 PLUS.
文摘To maintain the calmness of the harbor,rubble mound breakwaters are one of the practical measures to protect sailing and mooring waters.This paper investigates the effect of relocated rubble mound breakwaters on tranquillity in Busan yacht range and the impact of bridge piers at the entrance of the yacht range based on physical hydraulic modeling using multi-directional random waves.It is obtained that the sufficient tranquillity can be due to securely moored yachts,owing to newly relocated rubble mound breakwaters away from piers.The experimental results also showed the distribution of the energy difference’dependence on various wave directions.The experimental findings are valuable for the design of Busan yacht marina,and are of reference to other port projects.
基金supported by the National Natural Science Foundation of China(Grant Nos.11372224&11572225)
文摘Spiral waves have been observed in the biological experiments on rat cortex perfused with drugs which can block inhibitory synapse and switch neuron excitability from type II to type I. To simulate the spiral waves observed in the experiment, the spatiotemporal patterns are investigated in a network composed of neurons with type I and II excitabilities and excitatory coupling. Spiral waves emerge when the percentage(p) of neurons with type I excitability in the network is at middle levels, which is dependent on the coupling strength. Compared with other spatial patterns which appear at different p values, spiral waves exhibit optimal spatial correlation at a certain spatial frequency, implying the occurrence of spatial coherence resonance-like phenomenon. Some dynamical characteristics of the network such as mean firing frequency and synchronous degree can be well interpreted with distinct properties between type I excitability and type II excitability. The results not only identify dynamics of spiral waves in neuronal networks composed of neurons with different excitabilities, but also are helpful to understanding the emergence of spiral waves observed in the biological experiment.
