Applications of a constitutive framework providing compound complexity analysis and indexing of coarse-grained self-similar time series representing behavioural data are presented. A notion of behavioural entropy and ...Applications of a constitutive framework providing compound complexity analysis and indexing of coarse-grained self-similar time series representing behavioural data are presented. A notion of behavioural entropy and hysteresis is introduced as two different forms of compound measures. These measures provide clinically applicable complexity analysis of behavioural patterns yielding scalar characterisation of time-varying behaviours registered over an extended period of time. The behavioural data are obtained using body attached sensors providing non-invasive readings of heart rate, skin blood perfusion, blood oxygenation, skin temperature, movement and steps frequency. The results using compound measures of behavioural patterns of fifteen healthy individuals are presented. The application of the compound measures is shown to correlate with complexity analysis. The correlation is demonstrated using two healthy subjects compared against a control group. This indicates a possibility to use these measures in place of fractional dimensions to provide a finer characterisation of behavioural patterns observed using sensory data acquired over a long period of time.展开更多
The precessing vortex core (PVC) in a cyclone separator plays an important role in the separation performance and in further understanding of the general law of periodic unsteady flow therein. In this paper, the unste...The precessing vortex core (PVC) in a cyclone separator plays an important role in the separation performance and in further understanding of the general law of periodic unsteady flow therein. In this paper, the unsteady flow field is investigated with particle image velocimetry (PIV), and the instantaneous velocity, vorticity, tangential velocity, and radial velocity are acquired by analyzing the images of instantaneous flow. It is for the first time reported that there is a centrifugal flow region close to the dust discharge zone and its maximum value is higher than the mean radial velocity. This discovery is very important for understanding the principle of separation of particles in the area of dust discharge. Determination of the frequency and amplitude of PVC was conducted in the region where the phenomenon of PVC is remarkable. Results agree well with those obtained by hot wire anemometry. The observations of the center of vortex core and the bimodal distribution of the amplitude of the PVC indicate the vortex core precesses around the geometric axis of the cyclone in its own way.展开更多
Three-Dimensional(3D)swirling flow structures,generated by a counter-rotating dualstage swirler in a confined chamber with a confinement ratio of 1.53,were experimentally investigated at Re=2.3×10^(5)using Tomogr...Three-Dimensional(3D)swirling flow structures,generated by a counter-rotating dualstage swirler in a confined chamber with a confinement ratio of 1.53,were experimentally investigated at Re=2.3×10^(5)using Tomographic Particle Image Velocimetry(Tomo-PIV)and planar Particle Image Velocimetry(PIV).Based on the analysis of the 3D time-averaged swirling flow structures and 3D Proper Orthogonal Decomposition(POD)of the Tomo-PIV data,typical coherent flow structures,including the Corner Recirculation Zone(CRZ),Central Recirculation Zone(CTRZ),and Lip Recirculation Zone(LRZ),were extracted.The counter-rotating dual-stage swirler with a Venturi flare generates the independence process of vortex breakdown from the main stage and pilot stage,leading to the formation of an LRZ and a smaller CTRZ near the nozzle outlet.The confinement squeezes the CRZ to the corner and causes a reverse rotation flow to limit the shape of the CTRZ.A large-scale flow structure caused by the main stage features an explosive breakup,flapping,and Precessing Vortex Core(PVC).The explosive breakup mode dominates the swirling flow structures owing to the expansion and construction of the main jet,whereas the flapping mode is related to the wake perturbation.Confinement limits the expansion of PVC and causes it to contract after the impacting area.展开更多
Large eddy simulations(LES) were performed to study the non-reacting flow fields of a Cambridge swirl burner. The dynamic Smagorinsky eddy viscosity model is used as the sub-grid scale turbulence model. Comparisons of...Large eddy simulations(LES) were performed to study the non-reacting flow fields of a Cambridge swirl burner. The dynamic Smagorinsky eddy viscosity model is used as the sub-grid scale turbulence model. Comparisons of experimental data show that the LES results are capable of predicting mean and root-mean-square velocity profiles. The LES results show that the annular swirling flow has a minor impact on the formation of the bluff-body recirculation zone. The vortex structures near the shear layers, visualized by the iso-surface of Q-criterion, display ring structures in non-swirling flow and helical structures in swirling flow near the burner exit. Spectral analysis was employed to predict the occurrence of flow oscillations induced by vortex shedding and precessing vortex core(PVC). In order to extract accurately the unsteady large-scale structures in swirling flow, a three-dimensional proper orthogonal decomposition(POD) method was developed to reconstruct turbulent fluctuating velocity fields. POD analysis reveals that flow fields contain co-existing helical and toroidal shaped coherent structures. The helical structure associated with the PVC is the most energetic dynamic flow structure. The latter toroidal structure associated with vortex shedding has lower energy content which indicates that it is a secondary structure.展开更多
We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot （QD） ring, which is introduced as Rashba spin-orbital interaction to act locally on one component ...We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot （QD） ring, which is introduced as Rashba spin-orbital interaction to act locally on one component quantum dot. It is found that the electronic current and spin current are sensitive to the systematic parameters. The interdot spin-flip term does not play a leading role in causing electronic and spin currents. Otherwise the spin precessing terra leads to shift of the peaks of the the spin-up and spin-down electronic currents in different directions and results in the spin current. Moreover, the spin-orbital interaction suppresses the nonlocal Andreev reflection, so we cannot obtain the pure spin current.展开更多
Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition is induced by a magnetic field directed along the axis of anisotropy, while the action of the periodic field perpendicular to the...Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition is induced by a magnetic field directed along the axis of anisotropy, while the action of the periodic field perpendicular to the main magnetic field has been analyzed. Under these conditions, the characteristics of arising equilibrium PBS are uniquely determined by the frequency of the periodic field, but the solitons with other frequencies are impossible. For such structure, the entropy increase connected with dissipation is compensated by the decrease of the entropy due to the external periodic field. It is shown that the equilibrium PBS are essentially the “self-organizing systems” that can arise spotaneously in a metastable state of ferromagnet.展开更多
Spin-polarized transport through a precessing magnetic spin coupled to ferromagnetic electrodes is studied using a non-equilibrium Green＇s function approach. The characteristic of conductance is obtained at zero temp...Spin-polarized transport through a precessing magnetic spin coupled to ferromagnetic electrodes is studied using a non-equilibrium Green＇s function approach. The characteristic of conductance is obtained at zero temperature. We find that competition between spin-exchange interaction on the spin site and spin-orbit interaction in the barriers dominates the resonant behavior of conductance. In a parallel configuration, conductance peaks have identical amplitude. With the angle θ increasing, the width of resonant peaks is broadened or narrowed for different spin coherent states. In an anti-parallel case, spin-flip tunneling in the barriers will essentially enhance amplitude of the conductance peak.展开更多
文摘Applications of a constitutive framework providing compound complexity analysis and indexing of coarse-grained self-similar time series representing behavioural data are presented. A notion of behavioural entropy and hysteresis is introduced as two different forms of compound measures. These measures provide clinically applicable complexity analysis of behavioural patterns yielding scalar characterisation of time-varying behaviours registered over an extended period of time. The behavioural data are obtained using body attached sensors providing non-invasive readings of heart rate, skin blood perfusion, blood oxygenation, skin temperature, movement and steps frequency. The results using compound measures of behavioural patterns of fifteen healthy individuals are presented. The application of the compound measures is shown to correlate with complexity analysis. The correlation is demonstrated using two healthy subjects compared against a control group. This indicates a possibility to use these measures in place of fractional dimensions to provide a finer characterisation of behavioural patterns observed using sensory data acquired over a long period of time.
基金Supported by the National Natural Science Foundation of China (No.20076028)
文摘The precessing vortex core (PVC) in a cyclone separator plays an important role in the separation performance and in further understanding of the general law of periodic unsteady flow therein. In this paper, the unsteady flow field is investigated with particle image velocimetry (PIV), and the instantaneous velocity, vorticity, tangential velocity, and radial velocity are acquired by analyzing the images of instantaneous flow. It is for the first time reported that there is a centrifugal flow region close to the dust discharge zone and its maximum value is higher than the mean radial velocity. This discovery is very important for understanding the principle of separation of particles in the area of dust discharge. Determination of the frequency and amplitude of PVC was conducted in the region where the phenomenon of PVC is remarkable. Results agree well with those obtained by hot wire anemometry. The observations of the center of vortex core and the bimodal distribution of the amplitude of the PVC indicate the vortex core precesses around the geometric axis of the cyclone in its own way.
基金supported by the National Natural Science Foundation of China(Nos.12232002,12072017,12002199,and 11721202)。
文摘Three-Dimensional(3D)swirling flow structures,generated by a counter-rotating dualstage swirler in a confined chamber with a confinement ratio of 1.53,were experimentally investigated at Re=2.3×10^(5)using Tomographic Particle Image Velocimetry(Tomo-PIV)and planar Particle Image Velocimetry(PIV).Based on the analysis of the 3D time-averaged swirling flow structures and 3D Proper Orthogonal Decomposition(POD)of the Tomo-PIV data,typical coherent flow structures,including the Corner Recirculation Zone(CRZ),Central Recirculation Zone(CTRZ),and Lip Recirculation Zone(LRZ),were extracted.The counter-rotating dual-stage swirler with a Venturi flare generates the independence process of vortex breakdown from the main stage and pilot stage,leading to the formation of an LRZ and a smaller CTRZ near the nozzle outlet.The confinement squeezes the CRZ to the corner and causes a reverse rotation flow to limit the shape of the CTRZ.A large-scale flow structure caused by the main stage features an explosive breakup,flapping,and Precessing Vortex Core(PVC).The explosive breakup mode dominates the swirling flow structures owing to the expansion and construction of the main jet,whereas the flapping mode is related to the wake perturbation.Confinement limits the expansion of PVC and causes it to contract after the impacting area.
基金supported by the National Natural Science Foundation of China(Grant Nos.51176178&91441117)the Key Program of National Natural Science Foundation of China(Grant No.50936005)
文摘Large eddy simulations(LES) were performed to study the non-reacting flow fields of a Cambridge swirl burner. The dynamic Smagorinsky eddy viscosity model is used as the sub-grid scale turbulence model. Comparisons of experimental data show that the LES results are capable of predicting mean and root-mean-square velocity profiles. The LES results show that the annular swirling flow has a minor impact on the formation of the bluff-body recirculation zone. The vortex structures near the shear layers, visualized by the iso-surface of Q-criterion, display ring structures in non-swirling flow and helical structures in swirling flow near the burner exit. Spectral analysis was employed to predict the occurrence of flow oscillations induced by vortex shedding and precessing vortex core(PVC). In order to extract accurately the unsteady large-scale structures in swirling flow, a three-dimensional proper orthogonal decomposition(POD) method was developed to reconstruct turbulent fluctuating velocity fields. POD analysis reveals that flow fields contain co-existing helical and toroidal shaped coherent structures. The helical structure associated with the PVC is the most energetic dynamic flow structure. The latter toroidal structure associated with vortex shedding has lower energy content which indicates that it is a secondary structure.
基金Project supported by the Natural Science Foundation of Education Bureau of Jiangsu Province of China (Grant Nos. 08KJB140002 and 09KJD430004)
文摘We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot （QD） ring, which is introduced as Rashba spin-orbital interaction to act locally on one component quantum dot. It is found that the electronic current and spin current are sensitive to the systematic parameters. The interdot spin-flip term does not play a leading role in causing electronic and spin currents. Otherwise the spin precessing terra leads to shift of the peaks of the the spin-up and spin-down electronic currents in different directions and results in the spin current. Moreover, the spin-orbital interaction suppresses the nonlocal Andreev reflection, so we cannot obtain the pure spin current.
文摘Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition is induced by a magnetic field directed along the axis of anisotropy, while the action of the periodic field perpendicular to the main magnetic field has been analyzed. Under these conditions, the characteristics of arising equilibrium PBS are uniquely determined by the frequency of the periodic field, but the solitons with other frequencies are impossible. For such structure, the entropy increase connected with dissipation is compensated by the decrease of the entropy due to the external periodic field. It is shown that the equilibrium PBS are essentially the “self-organizing systems” that can arise spotaneously in a metastable state of ferromagnet.
文摘Spin-polarized transport through a precessing magnetic spin coupled to ferromagnetic electrodes is studied using a non-equilibrium Green＇s function approach. The characteristic of conductance is obtained at zero temperature. We find that competition between spin-exchange interaction on the spin site and spin-orbit interaction in the barriers dominates the resonant behavior of conductance. In a parallel configuration, conductance peaks have identical amplitude. With the angle θ increasing, the width of resonant peaks is broadened or narrowed for different spin coherent states. In an anti-parallel case, spin-flip tunneling in the barriers will essentially enhance amplitude of the conductance peak.
