In a magnetic nanostripe, the effects of perpendicular magnetic anisotropy(PMA) on the current-driven horizontal motion of vortex wall along the stripe and the vertical motion of the vortex core are studied by micro...In a magnetic nanostripe, the effects of perpendicular magnetic anisotropy(PMA) on the current-driven horizontal motion of vortex wall along the stripe and the vertical motion of the vortex core are studied by micromagnetic simulations.The results show that the horizontal and vertical motion can generally be monotonously enhanced by PMA. However, when the current is small, a nonmonotonic phenomenon for the horizontal motion is found. Namely, the velocity of the horizontal motion firstly decreases and then increases with the increase of the PMA. We find that the reason for this is that the PMA can firstly increase and then decrease the confining force induced by the confining potential energy. In addition, the PMA always enhances the driving force induced by the current.展开更多
The relation between domain wall motion and intensity of driven current is examined in a phenomenological theory where the kinetic energy is expanded as a series of polynomial function of current density just as the L...The relation between domain wall motion and intensity of driven current is examined in a phenomenological theory where the kinetic energy is expanded as a series of polynomial function of current density just as the Landau phase transition theory. The dependency of velocity on current density is square root which degenerates into linear if the current is much higher than the critical value. The theory result is consistent with several previous experiments and also can explain the change of critical current in the presence of temperature. The role of temperature playing in the dynamics of domain wall motion is also discussed. The phase transition theory in terms of current density is employed to explain the critical behavior of domain wall motion.展开更多
The effect of mechanical properties of erythrocytes on the near-wall motion of platelets was numerically studied with the immersed boundary method. Cells were modeled as viscous-fluid-filled capsules surrounded by hyp...The effect of mechanical properties of erythrocytes on the near-wall motion of platelets was numerically studied with the immersed boundary method. Cells were modeled as viscous-fluid-filled capsules surrounded by hyper-elastic membranes with negligible thickness. The numerical results show that with the increase of hematocrit, the near-wall approaching of platelets is enhanced, with which platelets exhibit larger deformation and orientation angle of its near-wall tank-treading motion, and the lateral force pushing platelets to the wall is increased with larger fluctuation amplitude. Meanwhile the near-wall approaching is reduced by increasing the stiffness of erythrocytes.展开更多
Objective To investigate the effects of puerarin (Pur) on myocardial perfusion and ventricular wall motion in patients with acute coronary syndrome (ACS).Methods Thirty-seven patients with ACS were randomly divided in...Objective To investigate the effects of puerarin (Pur) on myocardial perfusion and ventricular wall motion in patients with acute coronary syndrome (ACS).Methods Thirty-seven patients with ACS were randomly divided into two groups:conventional treatment group (n= 17,11 males,range of age:32-80 years,average age:60.9±4.9 years) and Pur treatment group (n=20,12 males,range of age:40-76 years,average age:62.7±3.5 years).Patients in the conventional treatment group received standard treatment according to the current guidelines,while patients in the Pur treatment group received intravenous administration of Pur (500 mg/day) for 10 days plus conventional treatment.Real-time myocardial contrast echocardiography (RT-MCE) was performed to evaluate the change in myocardial perfusion index (MPI) and ventricular wall motion index (VWMI) at admission and 10 days after treatment.Results At 10 days after treatment,MPI was significantly higher (P【0.01) and VWMI significantly lower (P【0.01) in the Pur group comparing with those in the conventional group.Conclusions Puerarin might improve myocardial microcirculation perfusion and ventricular wall motion in patients with ACS.展开更多
In this paper, we study the likelihood of chaos appearance during domain wall motion induced by electronic transfer. Considering a time-varying current density theory, we proceed to a numerical investigation of the dy...In this paper, we study the likelihood of chaos appearance during domain wall motion induced by electronic transfer. Considering a time-varying current density theory, we proceed to a numerical investigation of the dynamics. Using the dissipation parameter, amplitude and frequency of current density as control parameters;we show how periodic regime as well as chaotic regime can be exhibited in nanomagnetic systems. Numerical results allow setting up the periodicity and quasi-periodicity of system and chaotic phenomena occurring during magnetization switching process in nanomagnet through electronic transfer.展开更多
Owing to the existence of the flow field boundary, the shock wave load near the boundary is different from the freefield shock wave load. In the present paper, the hull plate load subjected to underwater shock wave is...Owing to the existence of the flow field boundary, the shock wave load near the boundary is different from the freefield shock wave load. In the present paper, the hull plate load subjected to underwater shock wave is investigated based onwave motion theories; in addition, the experimental study of the hull plate load is carried out. According to the theoreticalanalysis of the hull plate pressure, we find that the hull plate pressure oscillates repeatedly and decays rapidly with timepassing, the maximum hull plate pressure is 2/(1+n) times the maximum free field pressure, where n is the ratio ofimpedance, and the impulse is much smaller than the free field impulse. Compared with the experimental study, thetheoretical results agree well with the experimental data.展开更多
A boundary integral method was developed for simulating the motion and deformation of a viscous drop in an axisymmetric ambient Stokes flow near a rigid wall and for direct calculating the stress on the wall. Numerica...A boundary integral method was developed for simulating the motion and deformation of a viscous drop in an axisymmetric ambient Stokes flow near a rigid wall and for direct calculating the stress on the wall. Numerical experiments by the method were performed for different initial stand-off distances of the drop to the wall, viscosity ratios, combined surface tension and buoyancy parameters and ambient flow parameters. Numerical results show that due to the action of ambient flow and buoyancy the drop is compressed and stretched respectively in axial and radial directions when time goes. When the ambient flow action is weaker than that of the buoyancy the drop raises and bends upward and the stress on the wall induced by drop motion decreases when time advances. When the ambient flow action is stronger than that of the buoyancy the drop descends and becomes flatter and flatter as time goes. In this case when the initial stand-off distance is large the stress on the wall increases as the drop evolutes but when the stand-off distance is small the stress on the wall decreases as a result of combined effects of ambient flow, buoyancy and the stronger wall action to the flow. The action of the stress on the wall induced by drop motion is restricted in an area near the symmetric axis, which increases when the initial stand-off distance increases. When the initial stand-off distance increases the stress induced by drop motion decreases substantially. The surface tension effects resist the deformation and smooth the profile of the drop surfaces. The drop viscosity will reduce the deformation and migration of the drop.展开更多
A random synthesis procedure based on finite fault model is adopted for near field strong ground motion simulation in this paper. The fault plane of the source is divided into a number of sub-sources, the whole moment...A random synthesis procedure based on finite fault model is adopted for near field strong ground motion simulation in this paper. The fault plane of the source is divided into a number of sub-sources, the whole moment magnitude is also divided into more sub-events. The Fourier spectrum of ground motion caused by a sub-event in given sub-source, then can be derived by means of taking the point source spectrum, attenuation with distance, energy dissipation, and near surface effect, into account. A time history is synthesized from this amplitude spectrum and a random phase spectrum, and being combined with an envelope function. The ground motion is worked out by superposition of all time histories from each sub-event in each sub-source, with time lags determining by the differences between the triggering times of sub-events and distances of the sub-sources. From the example of simulations at 21 near field points in a scenario earthquake with 4 dip angles of the fault plane, it is illustrated that the procedure can describe the rupture directivity and hanging wall effect very well. To validate the procedure, the response spectra and time histories recorded at three near fault stations MCN, LV3 and PCD during the Northridge earthquake in 1994, are compared with the simulated ones.展开更多
A problem of couple motion between vessel wall and blood in the entrance regionof a tapered vessel is considered in this paper A mathematical model of co-coupleaction is formed for both motion of vessel wall and blood...A problem of couple motion between vessel wall and blood in the entrance regionof a tapered vessel is considered in this paper A mathematical model of co-coupleaction is formed for both motion of vessel wall and blood flow in the entrance regance regionof elastic vessel with tapered angle. Under the situation that the relative boundary conditions are satisfied a.set of velocity distribution formula. pressure distributionformula for the blood flow in a tapered elastic vessel are derived. Some importantconclusions are obtained.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11247026 and 11374253)
文摘In a magnetic nanostripe, the effects of perpendicular magnetic anisotropy(PMA) on the current-driven horizontal motion of vortex wall along the stripe and the vertical motion of the vortex core are studied by micromagnetic simulations.The results show that the horizontal and vertical motion can generally be monotonously enhanced by PMA. However, when the current is small, a nonmonotonic phenomenon for the horizontal motion is found. Namely, the velocity of the horizontal motion firstly decreases and then increases with the increase of the PMA. We find that the reason for this is that the PMA can firstly increase and then decrease the confining force induced by the confining potential energy. In addition, the PMA always enhances the driving force induced by the current.
文摘The relation between domain wall motion and intensity of driven current is examined in a phenomenological theory where the kinetic energy is expanded as a series of polynomial function of current density just as the Landau phase transition theory. The dependency of velocity on current density is square root which degenerates into linear if the current is much higher than the critical value. The theory result is consistent with several previous experiments and also can explain the change of critical current in the presence of temperature. The role of temperature playing in the dynamics of domain wall motion is also discussed. The phase transition theory in terms of current density is employed to explain the critical behavior of domain wall motion.
基金supported by the National Natural Science Foundation of China(11072155 and 11232010)Doctoral Fund of Ministry of Education of China(20100073120009)
文摘The effect of mechanical properties of erythrocytes on the near-wall motion of platelets was numerically studied with the immersed boundary method. Cells were modeled as viscous-fluid-filled capsules surrounded by hyper-elastic membranes with negligible thickness. The numerical results show that with the increase of hematocrit, the near-wall approaching of platelets is enhanced, with which platelets exhibit larger deformation and orientation angle of its near-wall tank-treading motion, and the lateral force pushing platelets to the wall is increased with larger fluctuation amplitude. Meanwhile the near-wall approaching is reduced by increasing the stiffness of erythrocytes.
基金Jiangsu Bureau of Traditimal Chinese Medicine (No.H05105)
文摘Objective To investigate the effects of puerarin (Pur) on myocardial perfusion and ventricular wall motion in patients with acute coronary syndrome (ACS).Methods Thirty-seven patients with ACS were randomly divided into two groups:conventional treatment group (n= 17,11 males,range of age:32-80 years,average age:60.9±4.9 years) and Pur treatment group (n=20,12 males,range of age:40-76 years,average age:62.7±3.5 years).Patients in the conventional treatment group received standard treatment according to the current guidelines,while patients in the Pur treatment group received intravenous administration of Pur (500 mg/day) for 10 days plus conventional treatment.Real-time myocardial contrast echocardiography (RT-MCE) was performed to evaluate the change in myocardial perfusion index (MPI) and ventricular wall motion index (VWMI) at admission and 10 days after treatment.Results At 10 days after treatment,MPI was significantly higher (P【0.01) and VWMI significantly lower (P【0.01) in the Pur group comparing with those in the conventional group.Conclusions Puerarin might improve myocardial microcirculation perfusion and ventricular wall motion in patients with ACS.
文摘In this paper, we study the likelihood of chaos appearance during domain wall motion induced by electronic transfer. Considering a time-varying current density theory, we proceed to a numerical investigation of the dynamics. Using the dissipation parameter, amplitude and frequency of current density as control parameters;we show how periodic regime as well as chaotic regime can be exhibited in nanomagnetic systems. Numerical results allow setting up the periodicity and quasi-periodicity of system and chaotic phenomena occurring during magnetization switching process in nanomagnet through electronic transfer.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51279038 and 51109042)the Natural Science Foundation of Heilongjiang Province of China(Grant No.E201124)
文摘Owing to the existence of the flow field boundary, the shock wave load near the boundary is different from the freefield shock wave load. In the present paper, the hull plate load subjected to underwater shock wave is investigated based onwave motion theories; in addition, the experimental study of the hull plate load is carried out. According to the theoreticalanalysis of the hull plate pressure, we find that the hull plate pressure oscillates repeatedly and decays rapidly with timepassing, the maximum hull plate pressure is 2/(1+n) times the maximum free field pressure, where n is the ratio ofimpedance, and the impulse is much smaller than the free field impulse. Compared with the experimental study, thetheoretical results agree well with the experimental data.
基金Project supported by the National Natural Science Foundation of China (No. 10272032)
文摘A boundary integral method was developed for simulating the motion and deformation of a viscous drop in an axisymmetric ambient Stokes flow near a rigid wall and for direct calculating the stress on the wall. Numerical experiments by the method were performed for different initial stand-off distances of the drop to the wall, viscosity ratios, combined surface tension and buoyancy parameters and ambient flow parameters. Numerical results show that due to the action of ambient flow and buoyancy the drop is compressed and stretched respectively in axial and radial directions when time goes. When the ambient flow action is weaker than that of the buoyancy the drop raises and bends upward and the stress on the wall induced by drop motion decreases when time advances. When the ambient flow action is stronger than that of the buoyancy the drop descends and becomes flatter and flatter as time goes. In this case when the initial stand-off distance is large the stress on the wall increases as the drop evolutes but when the stand-off distance is small the stress on the wall decreases as a result of combined effects of ambient flow, buoyancy and the stronger wall action to the flow. The action of the stress on the wall induced by drop motion is restricted in an area near the symmetric axis, which increases when the initial stand-off distance increases. When the initial stand-off distance increases the stress induced by drop motion decreases substantially. The surface tension effects resist the deformation and smooth the profile of the drop surfaces. The drop viscosity will reduce the deformation and migration of the drop.
基金Earthquake Science Foundation under Contract No.201009
文摘A random synthesis procedure based on finite fault model is adopted for near field strong ground motion simulation in this paper. The fault plane of the source is divided into a number of sub-sources, the whole moment magnitude is also divided into more sub-events. The Fourier spectrum of ground motion caused by a sub-event in given sub-source, then can be derived by means of taking the point source spectrum, attenuation with distance, energy dissipation, and near surface effect, into account. A time history is synthesized from this amplitude spectrum and a random phase spectrum, and being combined with an envelope function. The ground motion is worked out by superposition of all time histories from each sub-event in each sub-source, with time lags determining by the differences between the triggering times of sub-events and distances of the sub-sources. From the example of simulations at 21 near field points in a scenario earthquake with 4 dip angles of the fault plane, it is illustrated that the procedure can describe the rupture directivity and hanging wall effect very well. To validate the procedure, the response spectra and time histories recorded at three near fault stations MCN, LV3 and PCD during the Northridge earthquake in 1994, are compared with the simulated ones.
文摘A problem of couple motion between vessel wall and blood in the entrance regionof a tapered vessel is considered in this paper A mathematical model of co-coupleaction is formed for both motion of vessel wall and blood flow in the entrance regance regionof elastic vessel with tapered angle. Under the situation that the relative boundary conditions are satisfied a.set of velocity distribution formula. pressure distributionformula for the blood flow in a tapered elastic vessel are derived. Some importantconclusions are obtained.