Experimental confirmation discussed the effect of the immediate surroundings of a pulse-powered toroidal coil on biological material which was placed in an environment without the influence of electromagnetic force.
We investigate the electron transport and conductance properties in Fibonacci quasi-periodic graphene superlat- rices with electrostatic barriers and magnetic vector potentials. It is found that a new Dirac point appe...We investigate the electron transport and conductance properties in Fibonacci quasi-periodic graphene superlat- rices with electrostatic barriers and magnetic vector potentials. It is found that a new Dirac point appears in the band structure of graphene superlattice and the position of the Dirac point is exactly located at the energy corresponding to the zero-averaged w^ve number. The magnetic and eleetr/c potentials modify the energy band structure and transmission spectrum in entirely diverse ways. In addition, the angular-dependent transmission is blocked by the potential barriers at certain incident angles due to the appearance of the evanescent states. The effects of lattice constants and different potentials on angular-averaged conductance are also discussed.展开更多
The longitudinal wave term within Faraday’s law of electromagnetic induction (Faraday’s law) underwent recovery to ensure its suitability for theoretical derivation of the equation governing longitudinal electromagn...The longitudinal wave term within Faraday’s law of electromagnetic induction (Faraday’s law) underwent recovery to ensure its suitability for theoretical derivation of the equation governing longitudinal electromagnetic (LEM) waves. The revised Maxwell’s equations include the crucial parameters being the attenuation time constants of magnetic vortex potential and electric vortex potential generated by external electromagnetic field within the propagation medium. Specific expressions for them are obtained through theoretical analysis. Subsequently, a model for propagating magnetic P-wave generated by the superposition of a left-handed photo and a right-handed photon in a vacuum is formulated based on reevaluated total current law and revised Faraday’s law, covering wave equations, energy equation, as well as propagation mode involving mutual induction and conversion between scalar magnetic field and vortex electric field. Furthermore, through theoretical derivations centered around magnetic P-wave, evidence was presented regarding its ability to absorb huge free energy through the entangled interaction between zero-point vacuum energy field and the torsion field produced by the vortex electric field.展开更多
In this work we consider the following class of elliptic problems{−Δ_(A)u+u=a(x)|u|^(q−2)u+b(x)|u|^(p−2)u in R^(N),u∈H_(A)^(1)(R^(N)),(P)with 2<q<p<2^(∗)=2N/N−2,a(x)and b(x)are functions that can change sig...In this work we consider the following class of elliptic problems{−Δ_(A)u+u=a(x)|u|^(q−2)u+b(x)|u|^(p−2)u in R^(N),u∈H_(A)^(1)(R^(N)),(P)with 2<q<p<2^(∗)=2N/N−2,a(x)and b(x)are functions that can change sign and satisfy some additional conditions;u∈H_(A)^(1)(R^(N))and A:R^(N)→R^(N) is a magnetic potential.Also using the Nehari method in combination with other complementary arguments,we discuss the existence of infinitely many solutions to the problem in question,varying the assumptions about the weight functions.展开更多
In magnetoencephalography (MEG) a primary current is activated within a bounded conductive medium, i.e., the head. The primary current excites an induction current and the total (primary plus induction) current ge...In magnetoencephalography (MEG) a primary current is activated within a bounded conductive medium, i.e., the head. The primary current excites an induction current and the total (primary plus induction) current generates a magnetic field which, outside the conductor, is irrotational and solenoidal. Consequently, the exterior magnetic field can be expressed as the gradient of a harmonic function, known as the magnetic potential. We show that for the case of a triaxial ellipsoidal conductor this potential is obtained by using integration along a specific path which is dictated by the geometrical characteristics of the ellipsoidal system as well as by utilizing special properties of ellipsoidal harmonics. The vector potential representation of the magnetic field is also obtained.展开更多
Non-vanishing electromagnetic properties of neutrinos have been predicted by many theories beyond the Standard Model, and an enhanced neutrino magnetic moment can have profound implications for fundamental physics. Th...Non-vanishing electromagnetic properties of neutrinos have been predicted by many theories beyond the Standard Model, and an enhanced neutrino magnetic moment can have profound implications for fundamental physics. The XENON1T experiment recently detected an excess of electron recoil events in the 1–7 keV energy range, which can be compatible with solar neutrino magnetic moment interaction at a most probable value of μ_(v) = 2.1 × 10^(-11)μ_(B).However, tritium backgrounds or solar axion interaction in this energy window are equally plausible causes.Upcoming multi-tonne noble liquid detectors will test these scenarios more in depth, but will continue to face similar ambiguity. We report a unique capability of future large liquid scintillator detectors to help resolve the potential neutrino magnetic moment scenario. With O(100) kton·year exposure of liquid scintillator to solar neutrinos, a sensitivity of μ_(v) < 10^(-11)μ_(B) can be reached at an energy threshold greater than 40 keV, where no tritium or solar axion events but only neutrino magnetic moment signal is still present.展开更多
This paper investigates the dynamics of dark solitons in a Bose-Einstein condensate with a magnetic trap and an optical lattice (OL) trap, and analyses the effects of the periodic OL potential on the dynamics by app...This paper investigates the dynamics of dark solitons in a Bose-Einstein condensate with a magnetic trap and an optical lattice (OL) trap, and analyses the effects of the periodic OL potential on the dynamics by applying the variational approach based on the renormalized integrals of motion. The results show that the dark soliton becomes only a standing-wave and free propagation of the dark soliton is not possible when the periodic length of the OL potential is approximately equal to the effective width of the dark soliton. When the periodic length is very small or very large, the effects of the OL potential on the dark soliton will be sharply reduced. Finally, the numerical results confirm these theoretical findings.展开更多
Magnetic shielding is very important in the design of a high-power dc comparator. This paper addressed the application of magnetic circuit method to calculate the magnetic shielding effectiveness of high-power dc comp...Magnetic shielding is very important in the design of a high-power dc comparator. This paper addressed the application of magnetic circuit method to calculate the magnetic shielding effectiveness of high-power dc comparators when an external radial magnetic field is added. The mathematical relationship between the magnetic shielding effectiveness and the parameters of the magnetic shielding body were obtained. To verify the validity of the calculation method, we developped a procedure to measure the magnetic shielding effectiveness of the magnetic body by measuring the induction voltage of the detection winding instead of the magnetic intensity at a point in the magnetic shielding body, making the manipulation much easier. The result calculated with the magnetic circuit method turns out to be closer to the measured one compared with that calculated with a conventional algorithm proposed by Ren, suggesting that the magnetic circuit method is an applicable tool for estimating the toroidal cavity magnetic shielding effectiveness of a heavy current comparator when a radial magnetic field is added.展开更多
Excellent fits were obtained by Talantsev (MPLB 33, 1950195, 2019) to the temperature (T)-dependent upper critical field (H<sub>c</sub><sub>2</sub>(T)) data of H<sub>3</sub>S report...Excellent fits were obtained by Talantsev (MPLB 33, 1950195, 2019) to the temperature (T)-dependent upper critical field (H<sub>c</sub><sub>2</sub>(T)) data of H<sub>3</sub>S reported by Mozaffari et al. [Nature Communications 10, 2522 (2019)] by employing four alternative phenomenological models, each of which invoked two or more properties from its sample-specific set S<sub>1</sub> = {T<sub>c</sub>, gap, coherence length, penetration depth, jump in sp.ht.} and a single value of the effective mass (m*) of an electron. Based on the premise that the variation of H<sub>c</sub><sub>2</sub>(T) is due to the variation of the chemical potential μ(T), we report here fits to the same data by employing a T-, μ- and m*-dependent equation for H<sub>c</sub><sub>2</sub>(T) and three models of μ(T), viz. the linear, the parabolic and the concave-upward model. For temperatures up to which the data are available, each of these provides a good fit. However, for lower values of T, their predictions differ. Notably, the predicted values of H<sub>c</sub><sub>2</sub>(0) are much higher than in any of the models dealt with by Talantsev. In sum, we show here that the addressed data are explicable in a framework comprising the set S<sub>2</sub> = {μ, m*, interaction parameter λ<sub>m</sub>, Landau index N<sub>L</sub>}, which is altogether different from S<sub>1</sub>.展开更多
Two-dimensional(2D) numerical simulations of thermochemical nonequilibrium inductively coupled plasma(ICP) flows inside a 10-kW inductively coupled plasma wind tunnel(ICPWT) were carried out with nitrogen as the...Two-dimensional(2D) numerical simulations of thermochemical nonequilibrium inductively coupled plasma(ICP) flows inside a 10-kW inductively coupled plasma wind tunnel(ICPWT) were carried out with nitrogen as the working gas.Compressible axisymmetric NavierStokes(N-S) equations coupled with magnetic vector potential equations were solved.A fourtemperature model including an improved electron-vibration relaxation time was used to model the internal energy exchange between electron and heavy particles.The third-order accuracy electron transport properties(3rd AETP) were applied to the simulations.A hybrid chemical kinetic model was adopted to model the chemical nonequilibrium process.The flow characteristics such as thermal nonequilibrium,inductive discharge,effects of Lorentz force were made clear through the present study.It was clarified that the thermal nonequilibrium model played an important role in properly predicting the temperature field.The prediction accuracy can be improved by applying the 3rd AETP to the simulation for this ICPWT.展开更多
We study the effects of the perpendicular magnetic and Aharonov-Bohm (AB) flux fields on the energy levels of a two-dimensional (2D) Klein Gordon (KG) particle subjected to an equal scalar and vector pseudo-harm...We study the effects of the perpendicular magnetic and Aharonov-Bohm (AB) flux fields on the energy levels of a two-dimensional (2D) Klein Gordon (KG) particle subjected to an equal scalar and vector pseudo-harmonic oscillator (PHO). We calculate the exact energy eigenvalues and normalized wave functions in terms of chemical potential param- eter, magnetic field strength, AB flux field, and magnetic quantum number by means of the Nikiforov Uvarov (NU) method. The non-relativistic limit, PHO, and harmonic oscillator solutions in the existence and absence of external fields are also obtained.展开更多
We investigated the electronic energy band and transport features of graphene superlattice with periodically modulated magnetic vector potential and electrostatic potential. It is found that both parallel magnetic vec...We investigated the electronic energy band and transport features of graphene superlattice with periodically modulated magnetic vector potential and electrostatic potential. It is found that both parallel magnetic vector potential and electrostatic potential can decisively shift Dirac point in a different way, which may be an efficient way to achieve electron or hole filter. We a/so find that applying modulated parallel and anti-parallel magnetic vector potential to the electrons can efficiently change electronic states between pass and stop states, which can be useful in designing electron or hole switches and lead to large magneto-resistance.展开更多
The combination of electroencephalogram (EEG) and functional magnetic resonance imaging(fMRI) is a very attractive aim in neuroscience in order to achieve both high temporal and spatial resolution for the non-invasive...The combination of electroencephalogram (EEG) and functional magnetic resonance imaging(fMRI) is a very attractive aim in neuroscience in order to achieve both high temporal and spatial resolution for the non-invasive study of cognitive brain function. In this paper, we record simultaneous EEG-fMRI of the same subject in emotional processing experiment in order to explore the characteristics of different emotional picture processing, and try to find the difference of the subjects' brain hemisphere while viewing different valence emotional pictures. The late positive potential(LPP) is a reliable electrophysiological index of emotional perception in humans. According to the analysis results, the slow-wave LPP and visual cortical blood oxygen level-dependent (BOLD) signals are both modulated by the rated intensity of picture arousal. The amplitude of the LPP correlate significantly with BOLD intensity in visual cortex, amygdala, temporal area, prefrontal and central areas across picture contents.展开更多
Aiming at the air-gap magnetic field excited by wall armatures,Laplace’s partial differential equation of air-gap magnetic potential is achieved by means of the electromagnetic field theory.According to the magnetic ...Aiming at the air-gap magnetic field excited by wall armatures,Laplace’s partial differential equation of air-gap magnetic potential is achieved by means of the electromagnetic field theory.According to the magnetic boundary conditions and the method of separation of variables,the magnetic potential of the air-gap magnetic field is obtained.Based on the magnetization force model and Lorentz force of ferromagnetic thin-walled structures,and introducing the electromagnetic constitutive relations and boundary conditions,the calculation model of electromagnetic force of the soft ferromagnetic thin plate moving in air-gap magnetic field is established.Considering geometric nonlinearity,expressions of strain energy and kinetic energy of the elastic thin plate and the work of forces are given,respectively.The magnetic-structure coupling nonlinear vibration equations of ferromagnetic thin plate parallel moving in the air-gap magnetic field excited by armatures are obtained by using the Hamilton principle,which can be of the characterization of the system dynamics model with electro-magneto-velocity-mechanical interaction.Through numerical examples,primary resonance characteristics of the strip thin plate under the action of air-gap magnetic force are obtained.The results show that the two stable amplitude values will increase as amplitude of magnetic potential increases and thickness of air-gap decreases,and the amplitude’s multi-valued region will change due to the varieties of magnetic potential,air-gap and velocity.The model established in this paper is a theoretical reference for investigation on the multi-field coupling dynamic behaviors of structures moving in complex electromagnetic fields.展开更多
For electromagnetic governing equations formulated by magnetic vector potential and electric scalar potential,its detailed numerical implementation is achieved by using meshless method and Galerkin approach.And essent...For electromagnetic governing equations formulated by magnetic vector potential and electric scalar potential,its detailed numerical implementation is achieved by using meshless method and Galerkin approach.And essential boundary and interface condition of electromagnetic field are imposed by means of Lagrange multiplier method.Furthermore,the influences of interpolation point number at essential boundary and interface on computational results are also discussed.Examples are given to validate the effects of meshless method and Lagrange multiplier approach for electromagnetic field.展开更多
We consider there is a vacancy in the plasma in the solar system,and calculate the vector potential produced by the magnetic field frozen in the plasma.The result shows that,in the vacancy,the vector potential produce...We consider there is a vacancy in the plasma in the solar system,and calculate the vector potential produced by the magnetic field frozen in the plasma.The result shows that,in the vacancy,the vector potential produced by the magnetic field frozen in the plasma is much less than the large scale cosmic vector potential.This means if our earth is in such a vacancy,the total vector potential on the surface of the earth is dominated by the cosmic magnetic vector potential,which gives a further support of the reliability of the limit on photon mass given by rotating torsion balance experiment [Phys.Rev.Lett.90(2003) 081801].展开更多
The charged vector ρ mesons in the presence of external magnetic fields at finite temperature T and chemical potential μ have been investigated in the framework of the Nambu-Jona-Lasinio model.We compute the masses ...The charged vector ρ mesons in the presence of external magnetic fields at finite temperature T and chemical potential μ have been investigated in the framework of the Nambu-Jona-Lasinio model.We compute the masses of charged ρ mesons numerically as a function of the magnetic field for different values of temperature and chemical potential.The self-energy of the ρ meson contains the quark-loop contribution,i.e.the leading order contribution in 1/NC expansion.The charged ρ meson mass decreases with the magnetic field and drops to zero at a critical magnetic field eBc,which indicates that the charged vector meson condensation,i.e.the electromagnetic superconductor can be induced above the critical magnetic field.Surprisingly,it is found that the charged ρ condensation can even survive at high temperature and density.At zero temperature,the critical magnetic field just increases slightly with the chemical potential,which indicates that charged ρ condensation might occur inside compact stars.At zero density,in the temperature range 0.2 — 0.5 GeV,the critical magnetic field for charged ρ condensation is in the range of 0.2 — 0.6 GeV^2,which indicates that a high temperature electromagnetic superconductor might be created at LHC.展开更多
文摘Experimental confirmation discussed the effect of the immediate surroundings of a pulse-powered toroidal coil on biological material which was placed in an environment without the influence of electromagnetic force.
文摘We investigate the electron transport and conductance properties in Fibonacci quasi-periodic graphene superlat- rices with electrostatic barriers and magnetic vector potentials. It is found that a new Dirac point appears in the band structure of graphene superlattice and the position of the Dirac point is exactly located at the energy corresponding to the zero-averaged w^ve number. The magnetic and eleetr/c potentials modify the energy band structure and transmission spectrum in entirely diverse ways. In addition, the angular-dependent transmission is blocked by the potential barriers at certain incident angles due to the appearance of the evanescent states. The effects of lattice constants and different potentials on angular-averaged conductance are also discussed.
文摘The longitudinal wave term within Faraday’s law of electromagnetic induction (Faraday’s law) underwent recovery to ensure its suitability for theoretical derivation of the equation governing longitudinal electromagnetic (LEM) waves. The revised Maxwell’s equations include the crucial parameters being the attenuation time constants of magnetic vortex potential and electric vortex potential generated by external electromagnetic field within the propagation medium. Specific expressions for them are obtained through theoretical analysis. Subsequently, a model for propagating magnetic P-wave generated by the superposition of a left-handed photo and a right-handed photon in a vacuum is formulated based on reevaluated total current law and revised Faraday’s law, covering wave equations, energy equation, as well as propagation mode involving mutual induction and conversion between scalar magnetic field and vortex electric field. Furthermore, through theoretical derivations centered around magnetic P-wave, evidence was presented regarding its ability to absorb huge free energy through the entangled interaction between zero-point vacuum energy field and the torsion field produced by the vortex electric field.
基金grants from FAPESP 2017/16108-6grants from FAPESP 2019/24901-3 and CNPq 307061/2018-3supported by CAPES/Brazil and the paper was completed while the second author was visiting the Departament of Mathematics of UFJF whose hospitality she gratefully acknowledges.
文摘In this work we consider the following class of elliptic problems{−Δ_(A)u+u=a(x)|u|^(q−2)u+b(x)|u|^(p−2)u in R^(N),u∈H_(A)^(1)(R^(N)),(P)with 2<q<p<2^(∗)=2N/N−2,a(x)and b(x)are functions that can change sign and satisfy some additional conditions;u∈H_(A)^(1)(R^(N))and A:R^(N)→R^(N) is a magnetic potential.Also using the Nehari method in combination with other complementary arguments,we discuss the existence of infinitely many solutions to the problem in question,varying the assumptions about the weight functions.
文摘In magnetoencephalography (MEG) a primary current is activated within a bounded conductive medium, i.e., the head. The primary current excites an induction current and the total (primary plus induction) current generates a magnetic field which, outside the conductor, is irrotational and solenoidal. Consequently, the exterior magnetic field can be expressed as the gradient of a harmonic function, known as the magnetic potential. We show that for the case of a triaxial ellipsoidal conductor this potential is obtained by using integration along a specific path which is dictated by the geometrical characteristics of the ellipsoidal system as well as by utilizing special properties of ellipsoidal harmonics. The vector potential representation of the magnetic field is also obtained.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA10010800)the Double First Class Start-up Fund (WF220442603) provided by Shanghai Jiao Tong Universitysupport from the CAS Center for Excellence in Particle Physics (CCEPP)。
文摘Non-vanishing electromagnetic properties of neutrinos have been predicted by many theories beyond the Standard Model, and an enhanced neutrino magnetic moment can have profound implications for fundamental physics. The XENON1T experiment recently detected an excess of electron recoil events in the 1–7 keV energy range, which can be compatible with solar neutrino magnetic moment interaction at a most probable value of μ_(v) = 2.1 × 10^(-11)μ_(B).However, tritium backgrounds or solar axion interaction in this energy window are equally plausible causes.Upcoming multi-tonne noble liquid detectors will test these scenarios more in depth, but will continue to face similar ambiguity. We report a unique capability of future large liquid scintillator detectors to help resolve the potential neutrino magnetic moment scenario. With O(100) kton·year exposure of liquid scintillator to solar neutrinos, a sensitivity of μ_(v) < 10^(-11)μ_(B) can be reached at an energy threshold greater than 40 keV, where no tritium or solar axion events but only neutrino magnetic moment signal is still present.
基金Project supported by the Research Program of the Hong Kong Polytechnic University (Grant No A-PA2Q)the Scientific and Technological Research Program of Education Department of Hubei Province, China (Grant No Z200722001)
文摘This paper investigates the dynamics of dark solitons in a Bose-Einstein condensate with a magnetic trap and an optical lattice (OL) trap, and analyses the effects of the periodic OL potential on the dynamics by applying the variational approach based on the renormalized integrals of motion. The results show that the dark soliton becomes only a standing-wave and free propagation of the dark soliton is not possible when the periodic length of the OL potential is approximately equal to the effective width of the dark soliton. When the periodic length is very small or very large, the effects of the OL potential on the dark soliton will be sharply reduced. Finally, the numerical results confirm these theoretical findings.
基金Funded by the Natural Science Foundation of China under the grant number 50277018.
文摘Magnetic shielding is very important in the design of a high-power dc comparator. This paper addressed the application of magnetic circuit method to calculate the magnetic shielding effectiveness of high-power dc comparators when an external radial magnetic field is added. The mathematical relationship between the magnetic shielding effectiveness and the parameters of the magnetic shielding body were obtained. To verify the validity of the calculation method, we developped a procedure to measure the magnetic shielding effectiveness of the magnetic body by measuring the induction voltage of the detection winding instead of the magnetic intensity at a point in the magnetic shielding body, making the manipulation much easier. The result calculated with the magnetic circuit method turns out to be closer to the measured one compared with that calculated with a conventional algorithm proposed by Ren, suggesting that the magnetic circuit method is an applicable tool for estimating the toroidal cavity magnetic shielding effectiveness of a heavy current comparator when a radial magnetic field is added.
文摘Excellent fits were obtained by Talantsev (MPLB 33, 1950195, 2019) to the temperature (T)-dependent upper critical field (H<sub>c</sub><sub>2</sub>(T)) data of H<sub>3</sub>S reported by Mozaffari et al. [Nature Communications 10, 2522 (2019)] by employing four alternative phenomenological models, each of which invoked two or more properties from its sample-specific set S<sub>1</sub> = {T<sub>c</sub>, gap, coherence length, penetration depth, jump in sp.ht.} and a single value of the effective mass (m*) of an electron. Based on the premise that the variation of H<sub>c</sub><sub>2</sub>(T) is due to the variation of the chemical potential μ(T), we report here fits to the same data by employing a T-, μ- and m*-dependent equation for H<sub>c</sub><sub>2</sub>(T) and three models of μ(T), viz. the linear, the parabolic and the concave-upward model. For temperatures up to which the data are available, each of these provides a good fit. However, for lower values of T, their predictions differ. Notably, the predicted values of H<sub>c</sub><sub>2</sub>(0) are much higher than in any of the models dealt with by Talantsev. In sum, we show here that the addressed data are explicable in a framework comprising the set S<sub>2</sub> = {μ, m*, interaction parameter λ<sub>m</sub>, Landau index N<sub>L</sub>}, which is altogether different from S<sub>1</sub>.
基金supported by Grant-in-Aid for Scientific Research(No.23560954)sponsored by the Japan Society for the Promotion of Science
文摘Two-dimensional(2D) numerical simulations of thermochemical nonequilibrium inductively coupled plasma(ICP) flows inside a 10-kW inductively coupled plasma wind tunnel(ICPWT) were carried out with nitrogen as the working gas.Compressible axisymmetric NavierStokes(N-S) equations coupled with magnetic vector potential equations were solved.A fourtemperature model including an improved electron-vibration relaxation time was used to model the internal energy exchange between electron and heavy particles.The third-order accuracy electron transport properties(3rd AETP) were applied to the simulations.A hybrid chemical kinetic model was adopted to model the chemical nonequilibrium process.The flow characteristics such as thermal nonequilibrium,inductive discharge,effects of Lorentz force were made clear through the present study.It was clarified that the thermal nonequilibrium model played an important role in properly predicting the temperature field.The prediction accuracy can be improved by applying the 3rd AETP to the simulation for this ICPWT.
文摘We study the effects of the perpendicular magnetic and Aharonov-Bohm (AB) flux fields on the energy levels of a two-dimensional (2D) Klein Gordon (KG) particle subjected to an equal scalar and vector pseudo-harmonic oscillator (PHO). We calculate the exact energy eigenvalues and normalized wave functions in terms of chemical potential param- eter, magnetic field strength, AB flux field, and magnetic quantum number by means of the Nikiforov Uvarov (NU) method. The non-relativistic limit, PHO, and harmonic oscillator solutions in the existence and absence of external fields are also obtained.
基金Supported by the Key Program of the National Natural Science Foundation of China under Grant No. 10832005
文摘We investigated the electronic energy band and transport features of graphene superlattice with periodically modulated magnetic vector potential and electrostatic potential. It is found that both parallel magnetic vector potential and electrostatic potential can decisively shift Dirac point in a different way, which may be an efficient way to achieve electron or hole filter. We a/so find that applying modulated parallel and anti-parallel magnetic vector potential to the electrons can efficiently change electronic states between pass and stop states, which can be useful in designing electron or hole switches and lead to large magneto-resistance.
基金The Open Project of the State Key Laboratory of Robotics and System at Harbin Institute of Technologygrant number:SKLRS-2010-2D-09,SKLRS-2010-MS-10+5 种基金National Natural Science Foundation of Chinagrant number:61201096Natural Science Foundation of Changzhou Citygrant number:CJ20110023Changzhou High-tech Reasearch Key Laboratory Projectgrant number:CM20123006
文摘The combination of electroencephalogram (EEG) and functional magnetic resonance imaging(fMRI) is a very attractive aim in neuroscience in order to achieve both high temporal and spatial resolution for the non-invasive study of cognitive brain function. In this paper, we record simultaneous EEG-fMRI of the same subject in emotional processing experiment in order to explore the characteristics of different emotional picture processing, and try to find the difference of the subjects' brain hemisphere while viewing different valence emotional pictures. The late positive potential(LPP) is a reliable electrophysiological index of emotional perception in humans. According to the analysis results, the slow-wave LPP and visual cortical blood oxygen level-dependent (BOLD) signals are both modulated by the rated intensity of picture arousal. The amplitude of the LPP correlate significantly with BOLD intensity in visual cortex, amygdala, temporal area, prefrontal and central areas across picture contents.
基金the National Natural Science Foundation of China(Grant Nos.12172321 and 11472239)the Hebei Provincial Natural Science Foundation of China(Grant No.A2020203007).
文摘Aiming at the air-gap magnetic field excited by wall armatures,Laplace’s partial differential equation of air-gap magnetic potential is achieved by means of the electromagnetic field theory.According to the magnetic boundary conditions and the method of separation of variables,the magnetic potential of the air-gap magnetic field is obtained.Based on the magnetization force model and Lorentz force of ferromagnetic thin-walled structures,and introducing the electromagnetic constitutive relations and boundary conditions,the calculation model of electromagnetic force of the soft ferromagnetic thin plate moving in air-gap magnetic field is established.Considering geometric nonlinearity,expressions of strain energy and kinetic energy of the elastic thin plate and the work of forces are given,respectively.The magnetic-structure coupling nonlinear vibration equations of ferromagnetic thin plate parallel moving in the air-gap magnetic field excited by armatures are obtained by using the Hamilton principle,which can be of the characterization of the system dynamics model with electro-magneto-velocity-mechanical interaction.Through numerical examples,primary resonance characteristics of the strip thin plate under the action of air-gap magnetic force are obtained.The results show that the two stable amplitude values will increase as amplitude of magnetic potential increases and thickness of air-gap decreases,and the amplitude’s multi-valued region will change due to the varieties of magnetic potential,air-gap and velocity.The model established in this paper is a theoretical reference for investigation on the multi-field coupling dynamic behaviors of structures moving in complex electromagnetic fields.
基金the National Natural Science Foundation of China(No.50875169)
文摘For electromagnetic governing equations formulated by magnetic vector potential and electric scalar potential,its detailed numerical implementation is achieved by using meshless method and Galerkin approach.And essential boundary and interface condition of electromagnetic field are imposed by means of Lagrange multiplier method.Furthermore,the influences of interpolation point number at essential boundary and interface on computational results are also discussed.Examples are given to validate the effects of meshless method and Lagrange multiplier approach for electromagnetic field.
文摘We consider there is a vacancy in the plasma in the solar system,and calculate the vector potential produced by the magnetic field frozen in the plasma.The result shows that,in the vacancy,the vector potential produced by the magnetic field frozen in the plasma is much less than the large scale cosmic vector potential.This means if our earth is in such a vacancy,the total vector potential on the surface of the earth is dominated by the cosmic magnetic vector potential,which gives a further support of the reliability of the limit on photon mass given by rotating torsion balance experiment [Phys.Rev.Lett.90(2003) 081801].
基金Supported by the NSFC(11275213,11261130311)(CRC 110 by DFG and NSFC)CAS Key Project(KJCX2-EW-N01)+1 种基金Youth Innovation Promotion Association of CASPartially Supported by China Postdoctoral Science Foundation(2014M550841)
文摘The charged vector ρ mesons in the presence of external magnetic fields at finite temperature T and chemical potential μ have been investigated in the framework of the Nambu-Jona-Lasinio model.We compute the masses of charged ρ mesons numerically as a function of the magnetic field for different values of temperature and chemical potential.The self-energy of the ρ meson contains the quark-loop contribution,i.e.the leading order contribution in 1/NC expansion.The charged ρ meson mass decreases with the magnetic field and drops to zero at a critical magnetic field eBc,which indicates that the charged vector meson condensation,i.e.the electromagnetic superconductor can be induced above the critical magnetic field.Surprisingly,it is found that the charged ρ condensation can even survive at high temperature and density.At zero temperature,the critical magnetic field just increases slightly with the chemical potential,which indicates that charged ρ condensation might occur inside compact stars.At zero density,in the temperature range 0.2 — 0.5 GeV,the critical magnetic field for charged ρ condensation is in the range of 0.2 — 0.6 GeV^2,which indicates that a high temperature electromagnetic superconductor might be created at LHC.