Lift-off velocity of saltating sand particles in wind-blown sand located at 1.0 mm above the sand bed surface was measured using a phase Doppler particle analyzer in a wind tunnel. The results show that the probabilit...Lift-off velocity of saltating sand particles in wind-blown sand located at 1.0 mm above the sand bed surface was measured using a phase Doppler particle analyzer in a wind tunnel. The results show that the probability distribution of lift-off velocity can be expressed as a lognormal function, while that of lift-off angle follows an exponential function. The probability distribution of lift-off angle conditioned for each lift-off velocity also follows an exponential function, with a slope that becomes steeper with increasing lift-off velocity. This implies that the probability distribution of lift-off velocity is strongly dependent on the lift-off angle. However, these lift-off parameters are generally treated as an independent joint probability distribution in the literature. Numerical simulations were carried out to investigate the effects of conditional versus independent joint probability distributions on the vertical sand mass flux distribution. The simulation results derived from the conditional joint probability distribution agree much better with experimental data than those from the independent ones. Thus, it is better to describe the lift-off velocity of saltating sand particles using the conditional joint probability distribution. These results improve our understanding of saltation processes in wind-blown sand.展开更多
Zero mass flux jets, synthesized by acoustic actuators, have been used for the purpose of jet mixing enhancement and jet vectoring. Zero mass flux jets composed of entirely entrained fluid allow momentum transfer into...Zero mass flux jets, synthesized by acoustic actuators, have been used for the purpose of jet mixing enhancement and jet vectoring. Zero mass flux jets composed of entirely entrained fluid allow momentum transfer into the embedding flow. In the present experiments, miniature scale high aspect ratio actuator jets are placed along the long sides and near the exit plane of a primary two dimensional jet. In different modes, the primary jet can be vectored either towards or away from the actuator jets and the jet mixing is enhanced. The disturbance of the excitation frequency is developed while the unstable frequency of the primary jet is completely suppressed.展开更多
Settling particulate matter (SPM) was collected by using sediment traps at four stations in a survey section from Qingdao to Cheju-do, across the Huanghai Sea cold water mass (HSCWM), in August 2002. The sediment ...Settling particulate matter (SPM) was collected by using sediment traps at four stations in a survey section from Qingdao to Cheju-do, across the Huanghai Sea cold water mass (HSCWM), in August 2002. The sediment traps were planted in three layers: the upper layer of the thermocline (ULT) above the HSCWM, the lower layer of the thermocline (LLT), and the bottom layer of water column (BL). To determine the particle flux, the contents of organic carbon (POC), organic nitrogen (PON), total carbon (PC), and total phosphorous (PP) in SPM were analyzed, and two flux models (Ⅰ and Ⅱ) were improved to calculate the resuspension ratio, with an assumption in Model Ⅰ that the vertical flux of SPM in the LLT equals the net vertical flux of SPM in the whole water column. An X value, i.e., the fraction of the resuspension flux originating from the surficial sediments nearby the sampling station, was deduced from Model Ⅰ to estimate the contribution of lateral currents to the total resuspension flux. The results showed that inorganic particles, fecal pellets, and miscellaneous aggregates were the major types of SPM in the HSCWM, and the contents of POC, PON, PC, and PP all decreased with water depth. A great deal of fecal pellets found in the LLT indicates that the main space producing biogenic SPM is the thermocline, and especially the LLT, where the C/N ratio is lower than that in the ULT. The resuspension ratios, 90%-96% among stations, imply strong impact ofresuspension on particle flux in the BL. These values were not significantly different between the two flux models, suggesting that the hypothesis in Model Ⅰ that the flux in the LLT equaling the net flux to the bottom is acceptable for shallow waters with stratification like the HSCWM. The POC export ratio from the HSCWM ranges from 35% to 68%. It benefits from the short sinking distance in shallow water. The upwelling in the HSCWM enhanced the POC flux through the water mass, and the lateral currents provides up to being greater than 50% ofresuspension flux in the BL according to evaluation of the X value.展开更多
Indian Central Water (ICW) and Subantarctic Mode Water (SAMW) formation rates are estimated from two air-sea flux products, the Comprehensive Ocean-Atmosphere Data Set (COADS) and the Southampton Oceanography Ce...Indian Central Water (ICW) and Subantarctic Mode Water (SAMW) formation rates are estimated from two air-sea flux products, the Comprehensive Ocean-Atmosphere Data Set (COADS) and the Southampton Oceanography Centre (SOC) climatology. The ICW formation is estimated to be 8 Sv (1 Sv = 106m3·s-1 ) from both products, with more contributions from freshwater flux. From the COADS product, the SAMW formation rate is estimated to be 31 Sv in the potential density range of 26.5-26.9σθ, with also a significant contribution from freshwater flux. However, the SAMW formation rate estimated from the SOC product is much smaller, which may be due to bias of the SOC heat flux. Poorer quality of the flux products in the Southern Ocean may also contribute to the difference.展开更多
Research on heat and mass flux yielded by modern seafloor hydrothermal activity is very important, because it is involved not only in the base of ocean environment research, but also in the historical evolution of sea...Research on heat and mass flux yielded by modern seafloor hydrothermal activity is very important, because it is involved not only in the base of ocean environment research, but also in the historical evolution of seawater properties. Currently, estimating heat flux is based on the observation data of hydrothermal smokers, low-temperature diffusive flow and mid-ocean ridge mainly. But there are some faults, for example, there is lack of a concurrent conductive item in estimating the heat flux by smokers and the error between the half-space cooling model and the observation data is too large. So, three kinds of methods are applied to re-estimating the heat flux of hydrothermal activity resepectively, corresponding estimation is 97. 359 GW by hydrothermal smoker and diffusive flow, 84.895 GW by hydrothermal plume, and 4. 11 TW by exponential attenuation method put forward by this paper. Research on mass flux estimation is relatively rare, the main reason for this is insufficient field observation data. Mass fluxes of different elements are calculated using hydrothermal vent fluid data from the TAG hydrothermal area on the Mid-Atlantic Ridge for the first time. Difference of estimations by different methods reflects the researching extent of hydrothermal activity, and systematically in - situ observation will help to estimate the contribution of hydrothermal activity to ocean chemical environment, ocean circulation and global climate precisely.展开更多
The present numerically study investigates the influence of the Hall current and constant heat flux on the Magneto hydrodynamic (MHD) natural convection boundary layer viscous incompressible fluid flow in the manifest...The present numerically study investigates the influence of the Hall current and constant heat flux on the Magneto hydrodynamic (MHD) natural convection boundary layer viscous incompressible fluid flow in the manifestation of transverse magnetic field near an inclined vertical permeable flat plate. It is assumed that the induced magnetic field is negligible compared with the imposed magnetic field. The governing boundary layer equations have been transferred into non-similar model by implementing similarity approaches. The physical dimensionless parameter has been set up into the model as Prandtl number, Eckert number, Magnetic parameter, Schmidt number, local Grashof number and local modified Grashof number. The numerical method of Nactsheim-Swigert shooting iteration technique together with Runge-Kutta six order iteration scheme has been used to solve the system of governing non-similar equations. The physical effects of the various parameters on dimensionless primary velocity profile, secondary velocity profile, and temperature and concentration profile are discussed graphically. Moreover, the local skin friction coefficient, the local Nusselt number and Sherwood number are shown in tabular form for various values of the parameters.展开更多
Reliable estimation of the mass-flux profiles of aeolian sediment is essential for predicting sediment transport rates accurately and designing measures to cope with wind-erosion. Vertical mass-flux profiles from seve...Reliable estimation of the mass-flux profiles of aeolian sediment is essential for predicting sediment transport rates accurately and designing measures to cope with wind-erosion. Vertical mass-flux profiles from seventeen wind-erosion events were re-evaluated using five typical models based on observed data obtained from a smooth bare field at the southern fringe of the Taklimakan Desert, China. The results showed that the exponential-function model and the logarithmic-function model exhibited the poorest fit between observed and predicted mass-flux profiles. The power-function model and the modified power-function model improved the fit to field data to an equivalent extent, while the five-parameter combined-function model with a scale constant(σ) of 0.00001 m(different from the σ value proposed by Fryear, which represented the height above which 50% of the total mass flux occurred) was verified as the best for describing the vertical aeolian sediment mass-flux profiles using goodness of fit(R2) and the Akaike Information Criterion(AIC) values to evaluate model performance. According to relationships among model parameters, the modified power model played a prominent explanatory role in describing the vertical profiles of the observed data, whereas the exponential model played a coordinating role. In addition, it was found that the vertical profiles could not be extrapolated using the five selected models or easily estimated using an efficient model without field observations by a near-surface sampler at 0 to 0.05 m.展开更多
Prediction of radon flux from the fractured zone of a propagating cave mine is basically associated with uncertainty and complexity. For instance, there is restricted access to these zones for field measure- ments, an...Prediction of radon flux from the fractured zone of a propagating cave mine is basically associated with uncertainty and complexity. For instance, there is restricted access to these zones for field measure- ments, and it is quite difficult to replicate the complex nature of both natural and induced fractures in these zones in laboratory studies. Hence, a technique for predicting radon flux from a fractured rock using a discrete fracture network (DFN) model is developed to address these difficulties. This model quantifies the contribution of fractures to the total radon flux, and estimates the fracture density from a measured radon flux considering the effects of advection, diffusion, as well as radon generation and decay. Radon generation and decay are classified as reaction processes. Therefore, the equation solved is termed as the advection-diffusion-reaction equation (ADRE). Peclet number (Pe), a conventional dimensionless parameter that indicates the ratio of mass transport by advection to diffusion, is used to classify the transport regimes. The results show that the proposed model effectively predicts radon flux from a fractured rock. An increase in fracture density for a rock sample with uniformly distributed radon generation rate can elevate radon flux significantly compared with another rock sample with an equivalent increase in radon generation rate. In addition to Pe, two other independent dimensionless parameters (derived for radon transport through fractures) significantly affect radon dimensionless flux. Findings provide insight into radon transport through fractured rocks and can be used to improve radon control measures for proactive mitigation.展开更多
On the basis of the conductivity temperature depth(CTD)observation data off the coast of the Philippines(7.5°–18°N,130°E–the east coast of the Philippines)in the fall of 2005,the water mass distributi...On the basis of the conductivity temperature depth(CTD)observation data off the coast of the Philippines(7.5°–18°N,130°E–the east coast of the Philippines)in the fall of 2005,the water mass distribution,geostrophic flow field,and heat budget are examined.Four water masses are present:the North Pacific Tropical Surface Water,the North Pacific Sub-surface Water,the North Pacific Intermediate Water,and the Antarctic Intermediate Water(AAIW).The previous three corresponded with the North Equatorial Current(NEC),the Kuroshio Current(KC),and the Mindanao Current(MC),respectively.AAIW is the source of the Mindanao Undercurrent.The mass transport of NEC,KC,and MC is 58.7,15,and 27.95Sv,respectively(relative to 1500db).NEC can be balanced by the transport across the whole transect 18°N(31.81 Sv)and 7.5°N(26.11 Sv)but not simply by KC and MC.Direct calculation is used to study the heat flux.In sum,1.45PW heat is transported outwards the observed region,which is much more than that released from the ocean to the air at the surface(0.05PW).The net heat lost decreased the water temperature by 0.75℃each month on average,and the trend agreed well with the SST change.Vertically,the heat transported by the currents is mainly completed in the upper 500 m.展开更多
Flare characteristics such as the flare occurrence number density and the distribution of peak flux as well as duration of flares occurring on either side of a coronal mass ejection(CME) onset time are studied. Whil...Flare characteristics such as the flare occurrence number density and the distribution of peak flux as well as duration of flares occurring on either side of a coronal mass ejection(CME) onset time are studied. While the flares are rather evenly distributed statistically on either side of the CME onset time,the flare peak flux and duration tend to decrease depending upon their occurrence either before or after the CME onset. This is consistent with the earlier findings that flares emit higher energy before a CME whereas the energy is less in flares occurring after a CME.展开更多
We need to solve a suitable exponential form of the position-dependent mass (PDM) Schr6dinger equation with a charged particle placed in the Hulthen plus Coulomb-like potential field and under the actions of the ext...We need to solve a suitable exponential form of the position-dependent mass (PDM) Schr6dinger equation with a charged particle placed in the Hulthen plus Coulomb-like potential field and under the actions of the external magnetic and Aharonov-Bohm (AB) flux fields. The bound state energies and their corresponding wave functions are calculated for the spatially-dependent mass distribution function of interest in physics. A few plots of some numerical results with respect to the energy are shown.展开更多
Almost half of the oceanic water columns exhibit double-diffusion. The importance of double-diffusion in global oceans’ salt and heat fluxes, water-mass formation and mixing, and circulation is increasingly recognize...Almost half of the oceanic water columns exhibit double-diffusion. The importance of double-diffusion in global oceans’ salt and heat fluxes, water-mass formation and mixing, and circulation is increasingly recognized. However, such an important physical process in the ocean has not been well studied. One of the reasons is the difficulty of parameterizing and quantifying the processes. The paper presented here attempts to quantify the double-diffusive fluxes of salt and heat in the ocean. Previous qualitative analysis by applying the water-mass Turner angle, mTu, to the North Pacific Intermediate Water (NPIW) layer showed a favorable condition for salt-fingering in the upper NPIW due to the overlying warm/salty water above the cold/fresh NPIW core, and a doubly-stable condition in the lower NPIW where potential temperature decreases with depth while salinity increases, inducing double stratification with respect to both potential temperature and salinity. The present study gives a quantitative estimate of double-diffusive fluxes of salt and heat contributed by salt-fingering in the upper NPIW layer.展开更多
A simple phenomenological model is developed, which indicates the existence of a direct link between the concept of rest mass of a particle and magnetodynamic energies associated to the formation of the particle. The ...A simple phenomenological model is developed, which indicates the existence of a direct link between the concept of rest mass of a particle and magnetodynamic energies associated to the formation of the particle. The model is based upon the principles of quantization and conservation of flux, well known for their application in superconductivity. The charge of particles is considered as forming vortices of superconducting currents, which we postulate are created by electromagnetic fluctuations from vacuum (or related processes). A new quantization rule gathers the size, the magnetic moment, and the rest mass of the particle and associates these quantities to the integer number of flux quanta that should be stored in the vortices corresponding to each particle. The model is applied to the electron, the muon, the proton, and the neutron. Quantitative consistency with available experimental data for these subatomic particles is obtained.展开更多
基金supported by the Fundamental Research Funds for the Central Universities of China(GK201503053)the National Natural Science Foundation of China(41601002)
文摘Lift-off velocity of saltating sand particles in wind-blown sand located at 1.0 mm above the sand bed surface was measured using a phase Doppler particle analyzer in a wind tunnel. The results show that the probability distribution of lift-off velocity can be expressed as a lognormal function, while that of lift-off angle follows an exponential function. The probability distribution of lift-off angle conditioned for each lift-off velocity also follows an exponential function, with a slope that becomes steeper with increasing lift-off velocity. This implies that the probability distribution of lift-off velocity is strongly dependent on the lift-off angle. However, these lift-off parameters are generally treated as an independent joint probability distribution in the literature. Numerical simulations were carried out to investigate the effects of conditional versus independent joint probability distributions on the vertical sand mass flux distribution. The simulation results derived from the conditional joint probability distribution agree much better with experimental data than those from the independent ones. Thus, it is better to describe the lift-off velocity of saltating sand particles using the conditional joint probability distribution. These results improve our understanding of saltation processes in wind-blown sand.
文摘Zero mass flux jets, synthesized by acoustic actuators, have been used for the purpose of jet mixing enhancement and jet vectoring. Zero mass flux jets composed of entirely entrained fluid allow momentum transfer into the embedding flow. In the present experiments, miniature scale high aspect ratio actuator jets are placed along the long sides and near the exit plane of a primary two dimensional jet. In different modes, the primary jet can be vectored either towards or away from the actuator jets and the jet mixing is enhanced. The disturbance of the excitation frequency is developed while the unstable frequency of the primary jet is completely suppressed.
文摘Settling particulate matter (SPM) was collected by using sediment traps at four stations in a survey section from Qingdao to Cheju-do, across the Huanghai Sea cold water mass (HSCWM), in August 2002. The sediment traps were planted in three layers: the upper layer of the thermocline (ULT) above the HSCWM, the lower layer of the thermocline (LLT), and the bottom layer of water column (BL). To determine the particle flux, the contents of organic carbon (POC), organic nitrogen (PON), total carbon (PC), and total phosphorous (PP) in SPM were analyzed, and two flux models (Ⅰ and Ⅱ) were improved to calculate the resuspension ratio, with an assumption in Model Ⅰ that the vertical flux of SPM in the LLT equals the net vertical flux of SPM in the whole water column. An X value, i.e., the fraction of the resuspension flux originating from the surficial sediments nearby the sampling station, was deduced from Model Ⅰ to estimate the contribution of lateral currents to the total resuspension flux. The results showed that inorganic particles, fecal pellets, and miscellaneous aggregates were the major types of SPM in the HSCWM, and the contents of POC, PON, PC, and PP all decreased with water depth. A great deal of fecal pellets found in the LLT indicates that the main space producing biogenic SPM is the thermocline, and especially the LLT, where the C/N ratio is lower than that in the ULT. The resuspension ratios, 90%-96% among stations, imply strong impact ofresuspension on particle flux in the BL. These values were not significantly different between the two flux models, suggesting that the hypothesis in Model Ⅰ that the flux in the LLT equaling the net flux to the bottom is acceptable for shallow waters with stratification like the HSCWM. The POC export ratio from the HSCWM ranges from 35% to 68%. It benefits from the short sinking distance in shallow water. The upwelling in the HSCWM enhanced the POC flux through the water mass, and the lateral currents provides up to being greater than 50% ofresuspension flux in the BL according to evaluation of the X value.
文摘Indian Central Water (ICW) and Subantarctic Mode Water (SAMW) formation rates are estimated from two air-sea flux products, the Comprehensive Ocean-Atmosphere Data Set (COADS) and the Southampton Oceanography Centre (SOC) climatology. The ICW formation is estimated to be 8 Sv (1 Sv = 106m3·s-1 ) from both products, with more contributions from freshwater flux. From the COADS product, the SAMW formation rate is estimated to be 31 Sv in the potential density range of 26.5-26.9σθ, with also a significant contribution from freshwater flux. However, the SAMW formation rate estimated from the SOC product is much smaller, which may be due to bias of the SOC heat flux. Poorer quality of the flux products in the Southern Ocean may also contribute to the difference.
基金This study was supported by the Major State Basic Research Program of China under contract No.G2000078503the National Natural Science Foundation of China under contract No.40246024.
文摘Research on heat and mass flux yielded by modern seafloor hydrothermal activity is very important, because it is involved not only in the base of ocean environment research, but also in the historical evolution of seawater properties. Currently, estimating heat flux is based on the observation data of hydrothermal smokers, low-temperature diffusive flow and mid-ocean ridge mainly. But there are some faults, for example, there is lack of a concurrent conductive item in estimating the heat flux by smokers and the error between the half-space cooling model and the observation data is too large. So, three kinds of methods are applied to re-estimating the heat flux of hydrothermal activity resepectively, corresponding estimation is 97. 359 GW by hydrothermal smoker and diffusive flow, 84.895 GW by hydrothermal plume, and 4. 11 TW by exponential attenuation method put forward by this paper. Research on mass flux estimation is relatively rare, the main reason for this is insufficient field observation data. Mass fluxes of different elements are calculated using hydrothermal vent fluid data from the TAG hydrothermal area on the Mid-Atlantic Ridge for the first time. Difference of estimations by different methods reflects the researching extent of hydrothermal activity, and systematically in - situ observation will help to estimate the contribution of hydrothermal activity to ocean chemical environment, ocean circulation and global climate precisely.
文摘The present numerically study investigates the influence of the Hall current and constant heat flux on the Magneto hydrodynamic (MHD) natural convection boundary layer viscous incompressible fluid flow in the manifestation of transverse magnetic field near an inclined vertical permeable flat plate. It is assumed that the induced magnetic field is negligible compared with the imposed magnetic field. The governing boundary layer equations have been transferred into non-similar model by implementing similarity approaches. The physical dimensionless parameter has been set up into the model as Prandtl number, Eckert number, Magnetic parameter, Schmidt number, local Grashof number and local modified Grashof number. The numerical method of Nactsheim-Swigert shooting iteration technique together with Runge-Kutta six order iteration scheme has been used to solve the system of governing non-similar equations. The physical effects of the various parameters on dimensionless primary velocity profile, secondary velocity profile, and temperature and concentration profile are discussed graphically. Moreover, the local skin friction coefficient, the local Nusselt number and Sherwood number are shown in tabular form for various values of the parameters.
基金financially supported by the Special Scientific Research Fund of Meteorological Public Welfare Profession of China (GYHY201106025)the National Natural Science Foundation of China (41471031)
文摘Reliable estimation of the mass-flux profiles of aeolian sediment is essential for predicting sediment transport rates accurately and designing measures to cope with wind-erosion. Vertical mass-flux profiles from seventeen wind-erosion events were re-evaluated using five typical models based on observed data obtained from a smooth bare field at the southern fringe of the Taklimakan Desert, China. The results showed that the exponential-function model and the logarithmic-function model exhibited the poorest fit between observed and predicted mass-flux profiles. The power-function model and the modified power-function model improved the fit to field data to an equivalent extent, while the five-parameter combined-function model with a scale constant(σ) of 0.00001 m(different from the σ value proposed by Fryear, which represented the height above which 50% of the total mass flux occurred) was verified as the best for describing the vertical aeolian sediment mass-flux profiles using goodness of fit(R2) and the Akaike Information Criterion(AIC) values to evaluate model performance. According to relationships among model parameters, the modified power model played a prominent explanatory role in describing the vertical profiles of the observed data, whereas the exponential model played a coordinating role. In addition, it was found that the vertical profiles could not be extrapolated using the five selected models or easily estimated using an efficient model without field observations by a near-surface sampler at 0 to 0.05 m.
基金the financial support from the National Institute for Occupational Safety and Health(NIOSH)(200-2014-59613)for conducting this research
文摘Prediction of radon flux from the fractured zone of a propagating cave mine is basically associated with uncertainty and complexity. For instance, there is restricted access to these zones for field measure- ments, and it is quite difficult to replicate the complex nature of both natural and induced fractures in these zones in laboratory studies. Hence, a technique for predicting radon flux from a fractured rock using a discrete fracture network (DFN) model is developed to address these difficulties. This model quantifies the contribution of fractures to the total radon flux, and estimates the fracture density from a measured radon flux considering the effects of advection, diffusion, as well as radon generation and decay. Radon generation and decay are classified as reaction processes. Therefore, the equation solved is termed as the advection-diffusion-reaction equation (ADRE). Peclet number (Pe), a conventional dimensionless parameter that indicates the ratio of mass transport by advection to diffusion, is used to classify the transport regimes. The results show that the proposed model effectively predicts radon flux from a fractured rock. An increase in fracture density for a rock sample with uniformly distributed radon generation rate can elevate radon flux significantly compared with another rock sample with an equivalent increase in radon generation rate. In addition to Pe, two other independent dimensionless parameters (derived for radon transport through fractures) significantly affect radon dimensionless flux. Findings provide insight into radon transport through fractured rocks and can be used to improve radon control measures for proactive mitigation.
基金supported by the National Natural Science Foundation of China (Nos. 41676004, 41506034, 41376001, 41376038, 41806123, 41430963)the Basic Scientific Fund for National Public Research Institutes of China (No. GY0213G02)+1 种基金the National Major Scientific Research Program (No. 2015CB954300)the National Science and Technology Major Project (No. 2016ZX05057015)
文摘On the basis of the conductivity temperature depth(CTD)observation data off the coast of the Philippines(7.5°–18°N,130°E–the east coast of the Philippines)in the fall of 2005,the water mass distribution,geostrophic flow field,and heat budget are examined.Four water masses are present:the North Pacific Tropical Surface Water,the North Pacific Sub-surface Water,the North Pacific Intermediate Water,and the Antarctic Intermediate Water(AAIW).The previous three corresponded with the North Equatorial Current(NEC),the Kuroshio Current(KC),and the Mindanao Current(MC),respectively.AAIW is the source of the Mindanao Undercurrent.The mass transport of NEC,KC,and MC is 58.7,15,and 27.95Sv,respectively(relative to 1500db).NEC can be balanced by the transport across the whole transect 18°N(31.81 Sv)and 7.5°N(26.11 Sv)but not simply by KC and MC.Direct calculation is used to study the heat flux.In sum,1.45PW heat is transported outwards the observed region,which is much more than that released from the ocean to the air at the surface(0.05PW).The net heat lost decreased the water temperature by 0.75℃each month on average,and the trend agreed well with the SST change.Vertically,the heat transported by the currents is mainly completed in the upper 500 m.
文摘Flare characteristics such as the flare occurrence number density and the distribution of peak flux as well as duration of flares occurring on either side of a coronal mass ejection(CME) onset time are studied. While the flares are rather evenly distributed statistically on either side of the CME onset time,the flare peak flux and duration tend to decrease depending upon their occurrence either before or after the CME onset. This is consistent with the earlier findings that flares emit higher energy before a CME whereas the energy is less in flares occurring after a CME.
文摘We need to solve a suitable exponential form of the position-dependent mass (PDM) Schr6dinger equation with a charged particle placed in the Hulthen plus Coulomb-like potential field and under the actions of the external magnetic and Aharonov-Bohm (AB) flux fields. The bound state energies and their corresponding wave functions are calculated for the spatially-dependent mass distribution function of interest in physics. A few plots of some numerical results with respect to the energy are shown.
基金a result of my short visit to the Physical Oceanography Laboratory of Ocean University of ChinaQingdao with support from the Foundation for Open Projects of the Key Lab.of Physical Oceanography,the Ministry of Education,China(No.200401).
文摘Almost half of the oceanic water columns exhibit double-diffusion. The importance of double-diffusion in global oceans’ salt and heat fluxes, water-mass formation and mixing, and circulation is increasingly recognized. However, such an important physical process in the ocean has not been well studied. One of the reasons is the difficulty of parameterizing and quantifying the processes. The paper presented here attempts to quantify the double-diffusive fluxes of salt and heat in the ocean. Previous qualitative analysis by applying the water-mass Turner angle, mTu, to the North Pacific Intermediate Water (NPIW) layer showed a favorable condition for salt-fingering in the upper NPIW due to the overlying warm/salty water above the cold/fresh NPIW core, and a doubly-stable condition in the lower NPIW where potential temperature decreases with depth while salinity increases, inducing double stratification with respect to both potential temperature and salinity. The present study gives a quantitative estimate of double-diffusive fluxes of salt and heat contributed by salt-fingering in the upper NPIW layer.
文摘A simple phenomenological model is developed, which indicates the existence of a direct link between the concept of rest mass of a particle and magnetodynamic energies associated to the formation of the particle. The model is based upon the principles of quantization and conservation of flux, well known for their application in superconductivity. The charge of particles is considered as forming vortices of superconducting currents, which we postulate are created by electromagnetic fluctuations from vacuum (or related processes). A new quantization rule gathers the size, the magnetic moment, and the rest mass of the particle and associates these quantities to the integer number of flux quanta that should be stored in the vortices corresponding to each particle. The model is applied to the electron, the muon, the proton, and the neutron. Quantitative consistency with available experimental data for these subatomic particles is obtained.