As a typical contact-free manipulation technique that removes friction and contamination risk,levitation has gradually become a preferred candidate for various applications.Magnetic levitation using diamagnetism,beyon...As a typical contact-free manipulation technique that removes friction and contamination risk,levitation has gradually become a preferred candidate for various applications.Magnetic levitation using diamagnetism,beyond Earnshaw’s theorem,is a kind of passive stable levitation that can be achieved at normal temperatures with no energy input.Appealingly,most seemingly nonmagnetic materials can be levitated in a magnetic field and can stabilize free levitation of magnetic materials.This review focuses on the fundamental principles of magnetic levitation using diamagnetism,with emphasis on its burgeoning applications.The theoretical basis associated with the magnetic levitation using diamagnetism is discussed by elucidating the characteristics of diamagnetic materials,and the key levitation mechanisms are clarified.Afterwards,state-of-the-art applications in various aspects,including sensing and measurement,actuating and micromanipulation,energy harvesting and magnetic gravity compensation,are summarized and compared.Finally,the review concludes with a brief outlook on future perspectives.展开更多
In this study,we present a comprehensive evaluation of the magnetic field measurements from the Vector Field Magnetometer(VFM)aboard the recently launched Macao Science Satellite-1(MSS-1).One-year data from November 2...In this study,we present a comprehensive evaluation of the magnetic field measurements from the Vector Field Magnetometer(VFM)aboard the recently launched Macao Science Satellite-1(MSS-1).One-year data from November 2,2023,to November 1,2024,are considered.The MSS-1 flies with a low inclination(41°)and is designed to provide high-resolution magnetic field measurements,especially for monitoring the evolution of the South Atlantic Anomaly.Earlier studies confirmed the possibility of using MSS-1A data to model the Earth’s main magnetic field(e.g.,Jiang Y et al.,2024).Therefore,in this study we focus on the magnetic signatures related to the external field,which are primarily associated with magnetospheric and ionospheric currents.The global distributions of the magnetic residuals from MSS-1A show a pattern consistent with that derived from the European Space Agency’s Swarm A satellite.A statistical survey of the conjugated observations(withΔt<5 min andΔR<150 km)between the two satellites showed that the difference between their magnetic residuals is within±3 nanoteslas.By separating the magnetic residuals at the noon and midnight hours,we see that the MSS-1A data can effectively capture features of the magnetospheric and ionospheric currents,such as the magnetospheric ring current and ionospheric equatorial electrojet.Moreover,the magnetic residuals from MSS-1A show a diamagnetic effect caused by post-sunset equatorial plasma bubbles,which also suggests that the MSS-1A data have the potential to reveal the ionospheric structures.The comprehensive evaluations performed within this study demonstrate that the MSS-1A provides high-quality magnetic field data reaching the level of the Swarm satellite,which enables a deeper understanding of the modeling of Earth’s magnetic field as well as monitoring of the magnetic environment.展开更多
At low temperature and under weak magnetic field, non-interacting Fermi gases reveal both Pauli paramagnetism and Landau diamagnetism, and the magnitude of the diamagnetic susceptibility is 1/3 of that of the paramagn...At low temperature and under weak magnetic field, non-interacting Fermi gases reveal both Pauli paramagnetism and Landau diamagnetism, and the magnitude of the diamagnetic susceptibility is 1/3 of that of the paramagnetic one. When the temperature is finite and the magnetic field is also finite, we demonstrate that the paramagnetism and diamagnetism start to deviate from the ratio 1/3. For understanding the magnetic properties of an ideal Fermi gas at quite low temperature and under quite weak magnetic field, we work out explicitly the third-order magnetic susceptibility in three cases, from intrinsic spin, orbital motion and in total. An interesting property is in third-order magnetic susceptibilities: when viewing individually, they are both diamagnetic, but in total it is paramagnetic.展开更多
The Fock-Darwin system is studied in noncommutative quantum mechanics. We not only obtain its energy eigenvalues and eigenstates in noncommutative phase space, but also give an electron orbit description as well as th...The Fock-Darwin system is studied in noncommutative quantum mechanics. We not only obtain its energy eigenvalues and eigenstates in noncommutative phase space, but also give an electron orbit description as well as the general expressions of the magnetization and the susceptibility in a noncommutative situation. Further, we discuss two particular cases of temperature and present some interesting results different from those obtained from usual quantum mechanics such as the susceptibility dependent on a magnetic field at high temperatures, the occurrence of the magnetization in a zero magnetic field and zero temperature limit, and so on.展开更多
With time-of-flight and electric field ionization detection technique, we investigate the motional Stark effect for highly excited Rydberg barium in high magnetic field and its active cancellation experimentally. In t...With time-of-flight and electric field ionization detection technique, we investigate the motional Stark effect for highly excited Rydberg barium in high magnetic field and its active cancellation experimentally. In the experiment, the atom beam is aligned at a small angle of 15° with respect to the magnetic field. The motional Stark effect cancellation is demonstrated on two sets of. circularly polarized spectra in static magnetic field B = 1.00000 Tesla and B = 1.70000 Tesla, respectively, although the effect is very small （- 3.5 Vcm^-1） in our apparatus configuration.展开更多
Electricity and magnetism are common features of our world. The subject of electromagnetic fields in empty space populated only by point charges or smooth charge distributions in space is well understood. In that case...Electricity and magnetism are common features of our world. The subject of electromagnetic fields in empty space populated only by point charges or smooth charge distributions in space is well understood. In that case, one deals with the classical theory of electrodynamics developed by J.C. Maxwell in 1864. Electromagnetism in the presence of matter is, however, a completely different problem. Microscopic electric behavior of homogeneous substances can in general be characterized fairly simply and completely. The theory that enables us to do this is fairly well understood. Sadly the situation is quite different for magnetism in matter. The study there is phenomenological. That is, the substance is characterized by a number of parameters and the experimentally determined relations among them. We are not aware of any successful microscopic theory of magnetism in matter. The microscopic theory of magnetic substances, a topic of fundamental and technological importance, is the subject of this paper.展开更多
Existence of the magnetic field of Saturn and the temperature around 70 - 100 K nearby of it bring us to the idea of diamagnetism and superconductivity of the rings particles. The rings could emerge from the icy parti...Existence of the magnetic field of Saturn and the temperature around 70 - 100 K nearby of it bring us to the idea of diamagnetism and superconductivity of the rings particles. The rings could emerge from the icy particles moving on chaotic orbits around Saturn within protoplanetary cloud. After appearance of the magnetic field of Saturn all chaotic orbits of icy particles start to shift to the magnetic equator plane, where there is a minimum of the particles magnetic energy, due to diamagnetic force of expulsion like Meissner phenomenon. Each particle comes to the stable position preventing its own horizontal and vertical shift. Particles are locked within three-dimensional magnetic well due to Abrikosov quantum vortex phenomenon for superconductor. This mechanism is valid and it works even particles have a small fraction of superconductor. Final picture is similar to the picture of iron particles forms the same shape around a magnet on laboratory table. Any other phenomena like gravity resonances, dusty plasma and others may bring some peculiarities to the final picture of the rings. It follows that magnetic field of Saturn and low temperature around of it are the main reason for the rings origin and the rings is product of the early time of the magnetic field of Saturn appearance. Additional matter to the rings also may come from the frozen water particles generated from the Saturn sputniks geysers due to magnetic coupling between planet and satellites. The data of Cassini mission to Saturn rings are conforming suggested theory of their origin and existence.展开更多
We consider the effect of a magnetic field on the motion of an atomic electron in its orbit. The usual treatment deals with the change in magnetic dipole moment assuming the electron's speed changes but the radius...We consider the effect of a magnetic field on the motion of an atomic electron in its orbit. The usual treatment deals with the change in magnetic dipole moment assuming the electron's speed changes but the radius of its orbit remains unchanged. We derive the change in the magnetic dipole moment allowing both the speed and the radius to change. The cases of fixed radius on one hand and of fixed speed on the other are treated as special cases of our general case.展开更多
The first part of this investigation analyzes the deep earthquake occurrences in Nazca subducting under South America. The depth taken is to get information about possible influences from the unknown materials and for...The first part of this investigation analyzes the deep earthquake occurrences in Nazca subducting under South America. The depth taken is to get information about possible influences from the unknown materials and formations under the crust. The results revealed the presence of malleable material, which is unbreakable and, therefore, unable to trigger earthquakes. The structure of those elements is diamagnetic, attracting ionized particles from the Van Allen belt region in the ionosphere. The charged particles travel towards Earth’s surface, enhanced during the geomagnetic storms. The South Atlantic Magnetic Anomaly (SAMA) found that the deformation suffered by the anomaly moving from South Africa to South America is, possibly due to a bulge of unknown flexible material buried underneath the oceanic and continental crust. The continental part is strengthening in weakness because the background also has a high amount of diamagnetic material in this region, and it would not happen over the Atlantic Ocean, where part of the deformation is placed.展开更多
Cassini measurements suggest that ice bodies of Saturn’s visible dense rings have diamagnetic properties. Recently, JWST confirmed the existence of water around forming planets and showed that the magnetic field play...Cassini measurements suggest that ice bodies of Saturn’s visible dense rings have diamagnetic properties. Recently, JWST confirmed the existence of water around forming planets and showed that the magnetic field plays an important role in the formation of planets. It follows that Saturn’s visible dense rings could arise from the ice bodies of a protoplanetary cloud the radius of the Roche limit under the mutual action of a diamagnetic expulsion force created by Saturn’s magnetic field, together with the action of Saturn’s gravitational and centrifugal forces. As a result, the Kepler’s orbits of the ice bodies of the protoplanetary cloud move into the plane of Saturn’s equator and origin highly compressed stable system of the visible dense rings with separate individual ice bodies. With the same orientation of magnetic moment of ice bodies, their repulsion and separation occur due to their magnetization by Saturn’s magnetic field. Ice bodies are also attracted to each other due to their own gravity. At the balance of the both forces, the ice bodies remain at an equilibrium distance between them. This provides important evidence of the nature of J. C. Maxwell’s discovery in 1856 that the visible dense rings of Saturn are not continuous, but composed of individual bodies. This theory can provide an explanation of the origin of Saturn’s visible dense rings and their structure observed by Cassini probe in 2004-2017. It could also improve purely gravitational models of the origin of Saturn’s visible dense rings, which can only show how additional ice could penetrate the visible dense rings, and cannot explain convincingly their origin and structure.展开更多
By using a rigid bulky carboxylic ligand a-cyanocinnamic acid(CCA),a dinuclear dysprosium(Ⅲ) complex [Dy_(2)(CCA)_(6)(MeOH)_(4)](1) was synthesized.Single crystal X-ray crystallography reveals that the two eight-coor...By using a rigid bulky carboxylic ligand a-cyanocinnamic acid(CCA),a dinuclear dysprosium(Ⅲ) complex [Dy_(2)(CCA)_(6)(MeOH)_(4)](1) was synthesized.Single crystal X-ray crystallography reveals that the two eight-coordinate dysprosium ions are bridged by four deprotonated carboxyl groups,forming a centrosymmetric paddle-wheel-1ike structure.Dynamic magnetic property measurements indicate that complex 1 displays field-induced slow magnetic relaxation.The temperature-dependent relaxation times can be fitted using Orbach and Raman processes with parameters of n=2.8(2),C=27(8) s^(-1)/K^(n),τ_(0)=5(2) × 10^(-10) s and U_(eff)=40(3) cm^(-1).Magnetic studies on the diamagnetic Y~Ⅲ-diluted analogue[Dy_(0.206)Y_(1.794)(CCA)_(6)(MeOH)_(4)](2) reveal its slow magnetic relaxation behavior without external dc field and the antiferromagnetic coupling between the Dy^(Ⅲ) ions in 1.Fits on the obtained relaxation times of 2lead to the parameters of n=4.5(3),C=0.7(2) s^(-1)/K^(n),τ_0=2.8(2) × 10^(-9) s and U_(eff)=38(2) cm^(-1).The results suggest that slow magnetic relaxation originates from the single-ion relaxation of Dy^(Ⅲ) ions.Moreover,the diamagnetic dilution can suppress other fast relaxation pathways at low temperature,on account of the elimination of magnetic coupling and dipolar interaction.Ab initio calculations were then performed on the single Dy^(Ⅲ) ion species {YDy} and indicate that the first excited Kramers doublets(KDs)lie at ca.76 cm^(-1),which is slightly higher than the experimental U_(eff) value.The intramolecular magnetic interactions were also calculated and indicate a weak ferromagnetic dipole-diploe magnetic interaction and an antiferromagnetic exchange coupling.展开更多
Zero resistance and Meissner effect are two crucial experimental evidences of superconductivity in determining a new kind of superconductor, which can be detected by transport and diamagnetic measurements. In this pap...Zero resistance and Meissner effect are two crucial experimental evidences of superconductivity in determining a new kind of superconductor, which can be detected by transport and diamagnetic measurements. In this paper, we briefly review the main transport and magnetization results on the one unit cell （1-UC） FeSe films grown on SrTiO3 （STO） substrates from our team in recent years, which identify the high temperature superconductivity in 1-UC FeSe films.展开更多
Simultaneous effects of conduction band non-parabolicity and hydrostatic pressure on the binding energies of 1S, 2S, and 2P states along with diamagnetic susceptibility of an on-center hydrogenic impurity confined in ...Simultaneous effects of conduction band non-parabolicity and hydrostatic pressure on the binding energies of 1S, 2S, and 2P states along with diamagnetic susceptibility of an on-center hydrogenic impurity confined in typical GaAs/Alx- Ga1-x As spherical quantum dots are theoretically investigated using the matrix diagonalization method. In this regard, the effect of band non-parabolieity has been performed using the Luttinger-Kohn effective mass equation. The binding energies and the diamagnetic susceptibility of the hydrogenic impurity are computed as a function of the dot radius and different values of the pressure in the presence of conduction band non-parabolicity effect. The results we arrived at are as follows： the incorporation of the band edge non-parabolicity increases the binding energies and decreases the absolute value of the diamagnetic susceptibility for a given pressure and radius; the binding energies increase and the magnitude of the diamagnetic susceptibility reduces with increasing pressure.展开更多
Chou and Chen’s report in the 1970s suggested conformational protein adaptation (CPA) might be influenced by low frequency phonons acting as “a possible information system”. This report proposes the universal force...Chou and Chen’s report in the 1970s suggested conformational protein adaptation (CPA) might be influenced by low frequency phonons acting as “a possible information system”. This report proposes the universal force of electromagnetism initiates the phonon system they cited as it per-turbs paramagnetic/diamagnetic dampers within the protein matrix to produce a quantized low frequency phonon signal series. (http://www.phy.ilstu.edu/~ren/phononsims/page3.html) The signal series is iteratively processed by the protein beta sub-unit, the system, to posi-tion the alpha sub-unit, the outcome, a classic non-linear resonance system resulting in con-formational protein adaptation (CPA). CPA “priming” enables a secondary ATP/redox driven power system to complete cell activity. The evolutionary appearance of these two systems reflects their hierarchy: 1) a low energy phonon driven information control circuit governed by principles of physics that, along with proteins, may have preceded planet earth, and 2), an ATP/redox power completion circuit directed by principles of chemistry that evolved in living systems 1 billion or more years after earth formed.展开更多
As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical sys...As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical systems.The foundation of a diamagnetic levitation system is mathematical modeling,which is essential for operating performance optimization and stability prediction.However,few studies on systematic mathematical modeling have been reported.In this study,a systematic mathematical model for a disc-shaped diamagnetically levitated rotor on a permanent magnet array is proposed.Based on the proposed model,the magnetic field distribution characteristics,diamagnetic levitation force characteristics(i.e.,levitation height and stiffness),and optimized theoretical conditions for realizing stable levitation are determined.Experiments are conducted to verify the feasibility of the proposed mathematical model.Theoretical predictions and experimental results indicate that increasing the levitation height enlarges the stable region.Moreover,with a further increase in the rotor radius,the stable regions of the rotor gradually diminish and even vanish.Thus,when the levitation height is fixed,a moderate rotor radius permits stable levitation.This study proposes a mathematical modeling method for a diamagnetic levitation system that has potential applications in miniaturized mechanical systems.展开更多
Three-dimensional Dirac semimetal Cd_(3)As_(2)has been considered as an excellent candidate for applications of electronic devices owing to its ultrahigh mobility and air-stability.However,current researches are focus...Three-dimensional Dirac semimetal Cd_(3)As_(2)has been considered as an excellent candidate for applications of electronic devices owing to its ultrahigh mobility and air-stability.However,current researches are focused mainly on the use of gate-voltage to control its carrier transport tunability,while the manipulation of transport properties by element-doping is quite limited.Here we report the tunable magneto-transport properties by adjusting Mn-doping in the Cd_(3)As_(2)compound.We find that Mnelement doping has a strong influence on the Fermi level positions,and the Fermi energy approaches to Dirac point with higher Mn-doping.More importantly,the introduction of Mn atoms transforms diamagnetic Cd_(3)As_(2)to anti ferromagnetic(Cd,Mn)_(3)As_(2),which provides an approach to control topological protected Dirac materials by ma nipulating antiferro magnetic order parameters.The Shubnikov-de Hass oscillation originates from the surface states,and the Landau fan diagram yields a nontrivial Berry phase,indicating the existence of massless Dirac fermions in the(Cd_(1-x)Mn_x)_(3)AS_(2)compounds.Our present results may pave a way for further investigating anti ferromagnetic topological Dirac semimetal and expand the potential applications in optoelectronics and spintronics.展开更多
The spectra of Rydberg hydrogen atom in magnetic fields have been calculated using linear variational method with B-splines basis functions [Acta Phys. Sin. 55 （2006） 3380]. Based on these calculations we have done...The spectra of Rydberg hydrogen atom in magnetic fields have been calculated using linear variational method with B-splines basis functions [Acta Phys. Sin. 55 （2006） 3380]. Based on these calculations we have done some statistics analysis about the high Rydberg energy levels. The nearest-neighbor energy spacing distribution and the 3-statistics have been shown about diamagnetic Rydberg hydrogen atom with the magnetic field being 0.6 T and 6 T. The phenomena of multiply crossing, multiply anti-crossing, and the mixed of crossing and anti-crossing of energy levels have appeared in this paper. For both cases, in range of lower energy, the energy 1evel statistics properties close to Poisson distribution. With the increasing of the energy, the energy level statistics properties are away to Poisson distribution and tend to Wigner distribution step by step.展开更多
With the development of superconducting technology, the superconducting magnet, which can produce a stable large gradient high magnetic field (LG-HMF) environment to
A new long-pulse high electron temperature(Te)regime has been achieved on experimental advanced superconducting tokamak by pure radio frequency heating.In this new scenario,there are mainly two confinement states invo...A new long-pulse high electron temperature(Te)regime has been achieved on experimental advanced superconducting tokamak by pure radio frequency heating.In this new scenario,there are mainly two confinement states involving two magneto-hydrodynamic(MHD)modes,one of which is identified as m/n=1/1 kink mode(where m and n are the poloidal and toroidal mode numbers,respectively).The frequency evolution of the kink mode is investigated through the three-dimensional,toroidal,and nonlinear Hall-MHD code CLT.We firstly find that the frequency of the m/n=1/1 kink mode significantly increases during each sawtooth crash and then confirmed it through the experimental data.The simulation results indicate that the increase of the mode frequency is mainly due to the significant increase of the electron diamagnetic frequency nearby the reconnection region.We have also observed the internal transport barrier(ITB)during the m/n=1/1 kink mode.To further investigate this m/n=1/1 kink mode in this new regime,the multi-scale interactions between the m/n=1/1 kink mode and turbulence are discussed.展开更多
Generation of zonal flows by small-scale drift-Alfven modes is investigated by adopting the approach of parametric instability with the electron polarization drift included. The zonal mode can be excited by primary mo...Generation of zonal flows by small-scale drift-Alfven modes is investigated by adopting the approach of parametric instability with the electron polarization drift included. The zonal mode can be excited by primary modes propagating at both electron and ion diamagnetic drift directions in contrast to the assertion in previous studies that only primary modes propagating in the ion diamagnetic drift directions can drive zonal instabilities. Generally, the growth rate of the driven zonal mode is in the same order as that in previous study. However, different from the previous work, the growth rate is no longer proportional to the difference between the diamagnetic drift frequencies of electrons and ions.展开更多
基金supported by the Innovation Program of Shanghai Municipal Education Commission(Grant No.2019-01-07-00-02-E00030)the National Science Fund for Distinguished Young Scholars(Grant No.11625208)the Program of Shanghai Academic/Technology Research Leader(Grant No.19XD1421600)。
文摘As a typical contact-free manipulation technique that removes friction and contamination risk,levitation has gradually become a preferred candidate for various applications.Magnetic levitation using diamagnetism,beyond Earnshaw’s theorem,is a kind of passive stable levitation that can be achieved at normal temperatures with no energy input.Appealingly,most seemingly nonmagnetic materials can be levitated in a magnetic field and can stabilize free levitation of magnetic materials.This review focuses on the fundamental principles of magnetic levitation using diamagnetism,with emphasis on its burgeoning applications.The theoretical basis associated with the magnetic levitation using diamagnetism is discussed by elucidating the characteristics of diamagnetic materials,and the key levitation mechanisms are clarified.Afterwards,state-of-the-art applications in various aspects,including sensing and measurement,actuating and micromanipulation,energy harvesting and magnetic gravity compensation,are summarized and compared.Finally,the review concludes with a brief outlook on future perspectives.
基金supported by the National Natural Science Foundation of China(Grant Nos.42474200 and 42174186)Chao Xiong is supported by the Dragon 6 cooperation 2024-2028(Project No.95437).
文摘In this study,we present a comprehensive evaluation of the magnetic field measurements from the Vector Field Magnetometer(VFM)aboard the recently launched Macao Science Satellite-1(MSS-1).One-year data from November 2,2023,to November 1,2024,are considered.The MSS-1 flies with a low inclination(41°)and is designed to provide high-resolution magnetic field measurements,especially for monitoring the evolution of the South Atlantic Anomaly.Earlier studies confirmed the possibility of using MSS-1A data to model the Earth’s main magnetic field(e.g.,Jiang Y et al.,2024).Therefore,in this study we focus on the magnetic signatures related to the external field,which are primarily associated with magnetospheric and ionospheric currents.The global distributions of the magnetic residuals from MSS-1A show a pattern consistent with that derived from the European Space Agency’s Swarm A satellite.A statistical survey of the conjugated observations(withΔt<5 min andΔR<150 km)between the two satellites showed that the difference between their magnetic residuals is within±3 nanoteslas.By separating the magnetic residuals at the noon and midnight hours,we see that the MSS-1A data can effectively capture features of the magnetospheric and ionospheric currents,such as the magnetospheric ring current and ionospheric equatorial electrojet.Moreover,the magnetic residuals from MSS-1A show a diamagnetic effect caused by post-sunset equatorial plasma bubbles,which also suggests that the MSS-1A data have the potential to reveal the ionospheric structures.The comprehensive evaluations performed within this study demonstrate that the MSS-1A provides high-quality magnetic field data reaching the level of the Swarm satellite,which enables a deeper understanding of the modeling of Earth’s magnetic field as well as monitoring of the magnetic environment.
基金Supported by National Natural Science Foundation of China under Grant No.11675051
文摘At low temperature and under weak magnetic field, non-interacting Fermi gases reveal both Pauli paramagnetism and Landau diamagnetism, and the magnitude of the diamagnetic susceptibility is 1/3 of that of the paramagnetic one. When the temperature is finite and the magnetic field is also finite, we demonstrate that the paramagnetism and diamagnetism start to deviate from the ratio 1/3. For understanding the magnetic properties of an ideal Fermi gas at quite low temperature and under quite weak magnetic field, we work out explicitly the third-order magnetic susceptibility in three cases, from intrinsic spin, orbital motion and in total. An interesting property is in third-order magnetic susceptibilities: when viewing individually, they are both diamagnetic, but in total it is paramagnetic.
基金supported by the National Natural Science Foundation of China (Grant Nos 10575026 and 10875035)the Natural Science Foundation of Zhejiang Province,China (Grant No Y607437)
文摘The Fock-Darwin system is studied in noncommutative quantum mechanics. We not only obtain its energy eigenvalues and eigenstates in noncommutative phase space, but also give an electron orbit description as well as the general expressions of the magnetization and the susceptibility in a noncommutative situation. Further, we discuss two particular cases of temperature and present some interesting results different from those obtained from usual quantum mechanics such as the susceptibility dependent on a magnetic field at high temperatures, the occurrence of the magnetization in a zero magnetic field and zero temperature limit, and so on.
基金Supported by the National Natural Science Foundation of China under Grant No 10404033.
文摘With time-of-flight and electric field ionization detection technique, we investigate the motional Stark effect for highly excited Rydberg barium in high magnetic field and its active cancellation experimentally. In the experiment, the atom beam is aligned at a small angle of 15° with respect to the magnetic field. The motional Stark effect cancellation is demonstrated on two sets of. circularly polarized spectra in static magnetic field B = 1.00000 Tesla and B = 1.70000 Tesla, respectively, although the effect is very small （- 3.5 Vcm^-1） in our apparatus configuration.
文摘Electricity and magnetism are common features of our world. The subject of electromagnetic fields in empty space populated only by point charges or smooth charge distributions in space is well understood. In that case, one deals with the classical theory of electrodynamics developed by J.C. Maxwell in 1864. Electromagnetism in the presence of matter is, however, a completely different problem. Microscopic electric behavior of homogeneous substances can in general be characterized fairly simply and completely. The theory that enables us to do this is fairly well understood. Sadly the situation is quite different for magnetism in matter. The study there is phenomenological. That is, the substance is characterized by a number of parameters and the experimentally determined relations among them. We are not aware of any successful microscopic theory of magnetism in matter. The microscopic theory of magnetic substances, a topic of fundamental and technological importance, is the subject of this paper.
文摘Existence of the magnetic field of Saturn and the temperature around 70 - 100 K nearby of it bring us to the idea of diamagnetism and superconductivity of the rings particles. The rings could emerge from the icy particles moving on chaotic orbits around Saturn within protoplanetary cloud. After appearance of the magnetic field of Saturn all chaotic orbits of icy particles start to shift to the magnetic equator plane, where there is a minimum of the particles magnetic energy, due to diamagnetic force of expulsion like Meissner phenomenon. Each particle comes to the stable position preventing its own horizontal and vertical shift. Particles are locked within three-dimensional magnetic well due to Abrikosov quantum vortex phenomenon for superconductor. This mechanism is valid and it works even particles have a small fraction of superconductor. Final picture is similar to the picture of iron particles forms the same shape around a magnet on laboratory table. Any other phenomena like gravity resonances, dusty plasma and others may bring some peculiarities to the final picture of the rings. It follows that magnetic field of Saturn and low temperature around of it are the main reason for the rings origin and the rings is product of the early time of the magnetic field of Saturn appearance. Additional matter to the rings also may come from the frozen water particles generated from the Saturn sputniks geysers due to magnetic coupling between planet and satellites. The data of Cassini mission to Saturn rings are conforming suggested theory of their origin and existence.
文摘We consider the effect of a magnetic field on the motion of an atomic electron in its orbit. The usual treatment deals with the change in magnetic dipole moment assuming the electron's speed changes but the radius of its orbit remains unchanged. We derive the change in the magnetic dipole moment allowing both the speed and the radius to change. The cases of fixed radius on one hand and of fixed speed on the other are treated as special cases of our general case.
文摘The first part of this investigation analyzes the deep earthquake occurrences in Nazca subducting under South America. The depth taken is to get information about possible influences from the unknown materials and formations under the crust. The results revealed the presence of malleable material, which is unbreakable and, therefore, unable to trigger earthquakes. The structure of those elements is diamagnetic, attracting ionized particles from the Van Allen belt region in the ionosphere. The charged particles travel towards Earth’s surface, enhanced during the geomagnetic storms. The South Atlantic Magnetic Anomaly (SAMA) found that the deformation suffered by the anomaly moving from South Africa to South America is, possibly due to a bulge of unknown flexible material buried underneath the oceanic and continental crust. The continental part is strengthening in weakness because the background also has a high amount of diamagnetic material in this region, and it would not happen over the Atlantic Ocean, where part of the deformation is placed.
文摘Cassini measurements suggest that ice bodies of Saturn’s visible dense rings have diamagnetic properties. Recently, JWST confirmed the existence of water around forming planets and showed that the magnetic field plays an important role in the formation of planets. It follows that Saturn’s visible dense rings could arise from the ice bodies of a protoplanetary cloud the radius of the Roche limit under the mutual action of a diamagnetic expulsion force created by Saturn’s magnetic field, together with the action of Saturn’s gravitational and centrifugal forces. As a result, the Kepler’s orbits of the ice bodies of the protoplanetary cloud move into the plane of Saturn’s equator and origin highly compressed stable system of the visible dense rings with separate individual ice bodies. With the same orientation of magnetic moment of ice bodies, their repulsion and separation occur due to their magnetization by Saturn’s magnetic field. Ice bodies are also attracted to each other due to their own gravity. At the balance of the both forces, the ice bodies remain at an equilibrium distance between them. This provides important evidence of the nature of J. C. Maxwell’s discovery in 1856 that the visible dense rings of Saturn are not continuous, but composed of individual bodies. This theory can provide an explanation of the origin of Saturn’s visible dense rings and their structure observed by Cassini probe in 2004-2017. It could also improve purely gravitational models of the origin of Saturn’s visible dense rings, which can only show how additional ice could penetrate the visible dense rings, and cannot explain convincingly their origin and structure.
基金Project supported by the National Natural Science Foundation of China (21805048,22005069)the Natural Science Foundation of Guangdong Province (2022A1515011145,2023A1515010602)+2 种基金the Science and Technology Research Project of Guangzhou (202102080023,202201020166)the Project for Key Areas of Ordinary Colleges and Universities of Guangdong Province(2022ZDZX4035)the "Climbing Program" Special Funds of Guangdong Province (pdjh 2023b0389)。
文摘By using a rigid bulky carboxylic ligand a-cyanocinnamic acid(CCA),a dinuclear dysprosium(Ⅲ) complex [Dy_(2)(CCA)_(6)(MeOH)_(4)](1) was synthesized.Single crystal X-ray crystallography reveals that the two eight-coordinate dysprosium ions are bridged by four deprotonated carboxyl groups,forming a centrosymmetric paddle-wheel-1ike structure.Dynamic magnetic property measurements indicate that complex 1 displays field-induced slow magnetic relaxation.The temperature-dependent relaxation times can be fitted using Orbach and Raman processes with parameters of n=2.8(2),C=27(8) s^(-1)/K^(n),τ_(0)=5(2) × 10^(-10) s and U_(eff)=40(3) cm^(-1).Magnetic studies on the diamagnetic Y~Ⅲ-diluted analogue[Dy_(0.206)Y_(1.794)(CCA)_(6)(MeOH)_(4)](2) reveal its slow magnetic relaxation behavior without external dc field and the antiferromagnetic coupling between the Dy^(Ⅲ) ions in 1.Fits on the obtained relaxation times of 2lead to the parameters of n=4.5(3),C=0.7(2) s^(-1)/K^(n),τ_0=2.8(2) × 10^(-9) s and U_(eff)=38(2) cm^(-1).The results suggest that slow magnetic relaxation originates from the single-ion relaxation of Dy^(Ⅲ) ions.Moreover,the diamagnetic dilution can suppress other fast relaxation pathways at low temperature,on account of the elimination of magnetic coupling and dipolar interaction.Ab initio calculations were then performed on the single Dy^(Ⅲ) ion species {YDy} and indicate that the first excited Kramers doublets(KDs)lie at ca.76 cm^(-1),which is slightly higher than the experimental U_(eff) value.The intramolecular magnetic interactions were also calculated and indicate a weak ferromagnetic dipole-diploe magnetic interaction and an antiferromagnetic exchange coupling.
基金supported by the National Basic Research Program of China(Grant Nos.2013CB934600 and 2012CB921300)the National Natural Science Foundation of China(Grant Nos.11222434 and 11174007)the Research Fund for the Doctoral Program of Higher Education(RFDP)of China
文摘Zero resistance and Meissner effect are two crucial experimental evidences of superconductivity in determining a new kind of superconductor, which can be detected by transport and diamagnetic measurements. In this paper, we briefly review the main transport and magnetization results on the one unit cell （1-UC） FeSe films grown on SrTiO3 （STO） substrates from our team in recent years, which identify the high temperature superconductivity in 1-UC FeSe films.
文摘Simultaneous effects of conduction band non-parabolicity and hydrostatic pressure on the binding energies of 1S, 2S, and 2P states along with diamagnetic susceptibility of an on-center hydrogenic impurity confined in typical GaAs/Alx- Ga1-x As spherical quantum dots are theoretically investigated using the matrix diagonalization method. In this regard, the effect of band non-parabolieity has been performed using the Luttinger-Kohn effective mass equation. The binding energies and the diamagnetic susceptibility of the hydrogenic impurity are computed as a function of the dot radius and different values of the pressure in the presence of conduction band non-parabolicity effect. The results we arrived at are as follows： the incorporation of the band edge non-parabolicity increases the binding energies and decreases the absolute value of the diamagnetic susceptibility for a given pressure and radius; the binding energies increase and the magnitude of the diamagnetic susceptibility reduces with increasing pressure.
文摘Chou and Chen’s report in the 1970s suggested conformational protein adaptation (CPA) might be influenced by low frequency phonons acting as “a possible information system”. This report proposes the universal force of electromagnetism initiates the phonon system they cited as it per-turbs paramagnetic/diamagnetic dampers within the protein matrix to produce a quantized low frequency phonon signal series. (http://www.phy.ilstu.edu/~ren/phononsims/page3.html) The signal series is iteratively processed by the protein beta sub-unit, the system, to posi-tion the alpha sub-unit, the outcome, a classic non-linear resonance system resulting in con-formational protein adaptation (CPA). CPA “priming” enables a secondary ATP/redox driven power system to complete cell activity. The evolutionary appearance of these two systems reflects their hierarchy: 1) a low energy phonon driven information control circuit governed by principles of physics that, along with proteins, may have preceded planet earth, and 2), an ATP/redox power completion circuit directed by principles of chemistry that evolved in living systems 1 billion or more years after earth formed.
基金Supported by National Natural Science Foundation of China (Grant No.52275537)Nanjing Major Scientific and Technological Project of China (Grant No.202209011)。
文摘As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical systems.The foundation of a diamagnetic levitation system is mathematical modeling,which is essential for operating performance optimization and stability prediction.However,few studies on systematic mathematical modeling have been reported.In this study,a systematic mathematical model for a disc-shaped diamagnetically levitated rotor on a permanent magnet array is proposed.Based on the proposed model,the magnetic field distribution characteristics,diamagnetic levitation force characteristics(i.e.,levitation height and stiffness),and optimized theoretical conditions for realizing stable levitation are determined.Experiments are conducted to verify the feasibility of the proposed mathematical model.Theoretical predictions and experimental results indicate that increasing the levitation height enlarges the stable region.Moreover,with a further increase in the rotor radius,the stable regions of the rotor gradually diminish and even vanish.Thus,when the levitation height is fixed,a moderate rotor radius permits stable levitation.This study proposes a mathematical modeling method for a diamagnetic levitation system that has potential applications in miniaturized mechanical systems.
基金the National Natural Science Foundation of China(No.51771197)the Chinese Academy of Sciences(No.KJZD-EW-M05)the Liaoning Revitalization Talents Program(No.XLYC1807122)。
文摘Three-dimensional Dirac semimetal Cd_(3)As_(2)has been considered as an excellent candidate for applications of electronic devices owing to its ultrahigh mobility and air-stability.However,current researches are focused mainly on the use of gate-voltage to control its carrier transport tunability,while the manipulation of transport properties by element-doping is quite limited.Here we report the tunable magneto-transport properties by adjusting Mn-doping in the Cd_(3)As_(2)compound.We find that Mnelement doping has a strong influence on the Fermi level positions,and the Fermi energy approaches to Dirac point with higher Mn-doping.More importantly,the introduction of Mn atoms transforms diamagnetic Cd_(3)As_(2)to anti ferromagnetic(Cd,Mn)_(3)As_(2),which provides an approach to control topological protected Dirac materials by ma nipulating antiferro magnetic order parameters.The Shubnikov-de Hass oscillation originates from the surface states,and the Landau fan diagram yields a nontrivial Berry phase,indicating the existence of massless Dirac fermions in the(Cd_(1-x)Mn_x)_(3)AS_(2)compounds.Our present results may pave a way for further investigating anti ferromagnetic topological Dirac semimetal and expand the potential applications in optoelectronics and spintronics.
基金Supported by the National Natural Science Foundation of China under Grant No.10774042
文摘The spectra of Rydberg hydrogen atom in magnetic fields have been calculated using linear variational method with B-splines basis functions [Acta Phys. Sin. 55 （2006） 3380]. Based on these calculations we have done some statistics analysis about the high Rydberg energy levels. The nearest-neighbor energy spacing distribution and the 3-statistics have been shown about diamagnetic Rydberg hydrogen atom with the magnetic field being 0.6 T and 6 T. The phenomena of multiply crossing, multiply anti-crossing, and the mixed of crossing and anti-crossing of energy levels have appeared in this paper. For both cases, in range of lower energy, the energy 1evel statistics properties close to Poisson distribution. With the increasing of the energy, the energy level statistics properties are away to Poisson distribution and tend to Wigner distribution step by step.
基金supported by National Natural Foundation of China (No. 30670520)the National High-Tech R&D Program (863) of China (Key Program, 2008AA12A220)
文摘With the development of superconducting technology, the superconducting magnet, which can produce a stable large gradient high magnetic field (LG-HMF) environment to
基金supported by the National Magnetic Confinement Fusion Science Program of China (No. 11505226)National Natural Science Foundation of China (Nos. 11975273 and 12005185)+2 种基金the Fundamental Research Fund for Chinese Central Universities (No. 2021FZZX003-03-02)the Science Foundation of Institute of Plasma Physics, Chinese Academy of Sciences (Nos. DSJJ-202103 and DSJJ-2021-08)the National Key R&D Program of China (No. 2019YFE03010002)
文摘A new long-pulse high electron temperature(Te)regime has been achieved on experimental advanced superconducting tokamak by pure radio frequency heating.In this new scenario,there are mainly two confinement states involving two magneto-hydrodynamic(MHD)modes,one of which is identified as m/n=1/1 kink mode(where m and n are the poloidal and toroidal mode numbers,respectively).The frequency evolution of the kink mode is investigated through the three-dimensional,toroidal,and nonlinear Hall-MHD code CLT.We firstly find that the frequency of the m/n=1/1 kink mode significantly increases during each sawtooth crash and then confirmed it through the experimental data.The simulation results indicate that the increase of the mode frequency is mainly due to the significant increase of the electron diamagnetic frequency nearby the reconnection region.We have also observed the internal transport barrier(ITB)during the m/n=1/1 kink mode.To further investigate this m/n=1/1 kink mode in this new regime,the multi-scale interactions between the m/n=1/1 kink mode and turbulence are discussed.
基金supported by National Natural Science Foundation of China (No. 10775137)by the Ministry of Science and Technology of China (No. 2009CB105001)partly by the JSPS-CAS Core-University Program in the field of Plasma and Nuclear Fusion
文摘Generation of zonal flows by small-scale drift-Alfven modes is investigated by adopting the approach of parametric instability with the electron polarization drift included. The zonal mode can be excited by primary modes propagating at both electron and ion diamagnetic drift directions in contrast to the assertion in previous studies that only primary modes propagating in the ion diamagnetic drift directions can drive zonal instabilities. Generally, the growth rate of the driven zonal mode is in the same order as that in previous study. However, different from the previous work, the growth rate is no longer proportional to the difference between the diamagnetic drift frequencies of electrons and ions.
