There are two different viewpoints on the Aharonov-Bohm （A-B） effect. One asserts that the A-B effect is due to the existence of the vector potential A. The other asserts that the A-B effect is due to the interactio...There are two different viewpoints on the Aharonov-Bohm （A-B） effect. One asserts that the A-B effect is due to the existence of the vector potential A. The other asserts that the A-B effect is due to the interaction energy between the magnetic field produced by the moving charges and the magnetic field in the solenoid. The difference of these two viewpoints is analyzed in this paper. To judge which viewpoint is right, this paper suggests a new experimental method.展开更多
Invariant operator method for discrete or continuous spectrum eigenvalue and unitary transformation approach are employed to study the two-dimensional time-dependent Pauli equation in presence of the Aharonov-Bohm eff...Invariant operator method for discrete or continuous spectrum eigenvalue and unitary transformation approach are employed to study the two-dimensional time-dependent Pauli equation in presence of the Aharonov-Bohm effect （AB） and external scalar potential. For the spin particles the problem with the magnetic field is that it introduces a singularity into wave equation at the origin. A physical motivation is to replace the zero radius flux tube by one of radius R, with the additional condition that the magnetic field be confined to the surface of the tube, and then taking the limit R → 0 at the end of the computations. We point that the invariant operator must contain the step function θ（r - R）. Consequently, the problem becomes more complicated. In order to avoid this dimculty, we replace the radius R by ρ（t）R, where ρ（t） is a positive time-dependent function. Then at the end of calculations we take the limit R →0. The qualitative properties for the invariant operator spectrum are described separately for the different values of the parameter C appearing in the nonlinear auxiliary equation satisfied by p（t）, i.e., C 〉 0, C = 0, and C 〈0. Following the C＇s values the spectrum of quantum states is discrete （C 〉 0） or continuous （C ≤ 0）.展开更多
The 2D Pauli equation with Hulthen potential for spin-1/2 particle in the presence of Aharonov-Bohm （AB） field is solved analytically, on the assumption that an effective approximation is used for the centrifugal te...The 2D Pauli equation with Hulthen potential for spin-1/2 particle in the presence of Aharonov-Bohm （AB） field is solved analytically, on the assumption that an effective approximation is used for the centrifugal term. Singular and regular solutions of the problem are obtained. It is shown that the AB field lifts the degeneracy of the energy levels. The range of the flux parameter for which singular solutions are allowed is modified compared to the pure AB case. When the screening parameter vanishes, it is shown that the obtained energy spectrum becomes the same as that of the Aharonov-Bohm Coulomb problem.展开更多
The relativistic Aharonov-Bohm (AB) effect is studied using the time-dependent Dirac equation. It is shown that if the initial electron distribution is a pulse it is possible to define time-dependent signals that dist...The relativistic Aharonov-Bohm (AB) effect is studied using the time-dependent Dirac equation. It is shown that if the initial electron distribution is a pulse it is possible to define time-dependent signals that distinguish the AB effect from dipole and induced Coulomb interactions.展开更多
This article shows that in Aharonov-Bohm (AB) effect arrangements, the electron wave propagation space is doubly connected for two real coherent sources, and simply connected under certain condition for two virtual co...This article shows that in Aharonov-Bohm (AB) effect arrangements, the electron wave propagation space is doubly connected for two real coherent sources, and simply connected under certain condition for two virtual coherent sources, and all known AB experiments belong to the latter case. By the Feynman path integral method, we show that in the former case there is no AB effect, whereas in the latter case there is.展开更多
The AB(Aharonov-Bohm)effect is a pivotal quantum mechanical phenomenon that illustrates the fundamental role of the electromagnetic vector potential A in determining the phase of a charged particle’s wave function,ev...The AB(Aharonov-Bohm)effect is a pivotal quantum mechanical phenomenon that illustrates the fundamental role of the electromagnetic vector potential A in determining the phase of a charged particle’s wave function,even in regions where the magnetic field B is zero.This effect demonstrates that quantum particles are influenced not only by the fields directly present but also by the potentials associated with those fields.In the AB effect,an electron beam is split into two paths,with one path encircling a solenoid and the other bypassing it.Despite the absence of a magnetic field in the regions traversed by the beams,the vector potential A associated with the magnetic flux Φ through the solenoid induces a phase shift in the electron’s wave function.This phase shift,quantified by △φ=qΦ/hc,manifests as a change in the interference pattern observed in the detection screen.The phenomenon underscores the principle of gauge invariance in QED(quantum electrodynamics),where physical observables remain invariant under local gauge transformations of the vector and scalar potentials.This reinforces the notion that the vector potential A has a profound impact on quantum systems,beyond its classical role.This article outlines the AB effect,including its theoretical framework,experimental observations,and implications.The focus on the role of the vector potential in quantum mechanics provides a comprehensive understanding of this important phenomenon.展开更多
The gravitational Aharonov-Bohm(GAB)effect serves as the gravitational counterpart to the electromagnetic Aharonov-Bohm effect.Despite the concept’s inception in 1967,a rigorous experimental test of the GAB effect re...The gravitational Aharonov-Bohm(GAB)effect serves as the gravitational counterpart to the electromagnetic Aharonov-Bohm effect.Despite the concept’s inception in 1967,a rigorous experimental test of the GAB effect remains elusive.While recent endeavors with ground-based apparatus show promise in uncovering hints of the GAB effect,we propose a precise yet practical experiment to deterministically measure the GAB phase shift using cold atom interferometry in a microgravity environment,such as an orbital space station or drop tower.We conduct a thorough analysis of the experiment’s principles and derive key parameters.Our calculations suggest that it is feasible to precisely measure a significant GAB phase shift within known engineering constraints.Additionally,our design of the cold atom interferometer possesses a unique sensitivity to potential but insensitivity to force,which can be further refined to effectively mitigate adverse effects associated with nonzero inertial forces acting on the cold atoms.These endeavors will ultimately pave the way for experimental exploration into the quantum nature of gravity.展开更多
The Aharonov-Bohm(AB)effect is an important discovery of quantum theory.It serves as a surprising quantum phenomenon in which an electrically charged particle can be affected by an electromagnetic potential,despite be...The Aharonov-Bohm(AB)effect is an important discovery of quantum theory.It serves as a surprising quantum phenomenon in which an electrically charged particle can be affected by an electromagnetic potential,despite being confined to a region in which both the magnetic field and electric field are zero.This fact gives the electromagnetic potentials greater significance in quantum physics than in classical physics.The original AB effect belongs to an“electromagnetic type”.A certain vector potential is crucial for building a certain type of AB effect.In this work,we focus on the“spin”,which is an intrinsic property of microscopic particles that has been widely accepted nowadays.First,we propose the hypothesis of spin vector potential by considering a particle with a spin operator.Second,to verify the existence of such a spin vector potential,we present a gedanken double-slit interference experiment(i.e.,the spin AB effect),which is possible to be observed in the lab.Third,we apply the spin vector potential to naturally explain why there were the Dzyaloshinsky-Moriya-type interaction and the dipole-dipole interaction between spins,and also predict a new type of spin-orbital interaction.展开更多
Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms lig...Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms ligand bonds or hydrogen bonds with sulfur ions in lithium polysulfides(LiPSs),thus inhibiting the shuttle effect.Electrochemical analyses demonstrated that lithium‑sulfur(Li‑S)batteries employing the NH2‑SS interlayer exhibited discharge specific capacities of 1048 and 789 mAh·g^(-1) at 0.2C and 2C,respectively,and even at 4C,the initial discharge specific capacity remained at 590 mAh·g^(-1),outperforming the Li‑S battery with unmodified SS as the interlayer.展开更多
The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF...The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.展开更多
Agglomeration supports the high-quality development of the manufacturing industry,and its associated resource and environmental effects play a crucial role in driving green economic development.Based on data from pref...Agglomeration supports the high-quality development of the manufacturing industry,and its associated resource and environmental effects play a crucial role in driving green economic development.Based on data from prefecture-level cities in China from 2005 to 2019,this study employs the inverse distance weighting method,the bivariate local indicator of spatial association model,the spatial Durbin model,and other techniques to explore the relationship between manufacturing agglomeration and PM_(2.5)concentrations,and to assess the impact of its manufacturing agglomeration.Four correlation patterns are observed:high-high,low-low,high-low,and low-high.Among these,high-high and low-low patterns dominate in terms of number of cities.These correlation patterns demonstrate strong temporal stability,with a clear“Matthew effect”.The effect of manufacturing agglomeration on PM_(2.5)levels is significantly negative and helps reduce concentrations regionally,indicating the need to further enhance agglomeration levels regionally.However,it can increase PM_(2.5)levels in neighboring areas due to a siphon effect,and the impact of varies across regions.Compared with levels in 2005-2013,the significance of the relationship between manufacturing agglomeration and PM_(2.5)weakened in the 2013-2019 period.Accordingly,this study proposes countermeasures and policy recommendations aimed at strengthening regional collaborative governance and inspiring differentiated agglomeration strategies to support sustainable economic development in China.展开更多
Chitosan(CTS)was grafted onto the surface of amino‑functionalized silver chloride silicon dioxide(AgCl@SiO_(2)‑NH_(2))cores to obtain AgCl@SiO_(2)/CTS hybrid nanoparticles.The as‑obtained AgCl@SiO_(2)/CTS nanoparticle...Chitosan(CTS)was grafted onto the surface of amino‑functionalized silver chloride silicon dioxide(AgCl@SiO_(2)‑NH_(2))cores to obtain AgCl@SiO_(2)/CTS hybrid nanoparticles.The as‑obtained AgCl@SiO_(2)/CTS nanoparticles were chlorinated by NaClO solution to get AgCl@SiO_(2)/CTS‑based chloramine nano‑hybrid materials,denoted as AgCl@SiO_(2)/CTS‑Cl.A transmission electron microscope was used to observe the morphology of the as‑prepared samples AgCl@SiO_(2)/CTS and AgCl@SiO_(2)/CTS‑Cl.At the same time,an X‑ray diffractometer and an infrared spectroscope were utilized to characterize their crystal and chemical structures.Besides,ζpotentials were measured to elucidate the surface modification of AgCl nanoparticles by—NH_(2),the antibacterial mechanism of AgCl@SiO_(2)/CTS‑Cl was investigated by scanning electron microscopy,and Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were used as the to‑be‑tested strains to evaluate the antimicrobial activity of samples AgCl@SiO_(2)/CTS and AgCl@SiO_(2)/CTS‑Cl.Findings demonstrate that sample AgCl@SiO_(2)/CTS exhibits a chain‑like structure ascribed to the interaction between—NH_(2),and each AgCl@SiO_(2)/CTS hybrid nanoparticle contains several AgCl cores.In the meantime,sample AgCl@SiO_(2)/CTS‑Cl exhibits excellent antibacterial activity against E.coli and S.aureus,which is attributed to the synergistic antibacterial effect of Ag^(+)and Cl^(-).Sample AgCl@SiO_(2)/CTS‑Cl with a dosage of 640.00μg·mL^(-1) could completely kill the two kinds of tested bacteria in 12 h of incubation;it retains a high antibacterial efficiency even after 10 cycles of antibacterial tests.展开更多
Rechargeable Zn/Sn-air batteries have received considerable attention as promising energy storage devices.However,the electrochemical performance of these batteries is significantly constrained by the sluggish electro...Rechargeable Zn/Sn-air batteries have received considerable attention as promising energy storage devices.However,the electrochemical performance of these batteries is significantly constrained by the sluggish electrocatalytic reaction kinetics at the cathode.The integration of light energy into Zn/Sn-air batteries is a promising strategy for enhancing their performance.However,the photothermal and photoelectric effects generate heat in the battery under prolonged solar irradiation,leading to air cathode instability.This paper presents the first design and synthesis of Ni_(2)-1,5-diamino-4,8-dihydroxyanthraquinone(Ni_(2)DDA),an electronically conductiveπ-d conjugated metal-organic framework(MOF).Ni_(2)DDA exhibits both photoelectric and photothermal effects,with an optical band gap of~1.14 eV.Under illumination,Ni_(2)DDA achieves excellent oxygen evolution reaction performance(with an overpotential of 245 mV vs.reversible hydrogen electrode at 10 mA cm^(−2))and photothermal stability.These properties result from the synergy between the photoelectric and photothermal effects of Ni_(2)DDA.Upon integration into Zn/Sn-air batteries,Ni_(2)DDA ensures excellent cycling stability under light and exhibits remarkable performance in high-temperature environments up to 80℃.This study experimentally confirms the stable operation of photo-assisted Zn/Sn-air batteries under high-temperature conditions for the first time and provides novel insights into the application of electronically conductive MOFs in photoelectrocatalysis and photothermal catalysis.展开更多
The efficient electrocatalytic oxidation of glycerol(GLY)is one of the most promising routes for the valorization of GLY.Doping has emerged as a powerful strategy to tailor the electrocatalytic performance of silver n...The efficient electrocatalytic oxidation of glycerol(GLY)is one of the most promising routes for the valorization of GLY.Doping has emerged as a powerful strategy to tailor the electrocatalytic performance of silver nanoclusters(Ag NCs),yet the effects of doping mode(surface vs.core)and the interface environment(e.g.,electrolyte concentration)on the electrocatalytic performance for Ag NCs toward GLY oxidation remain understood.In this work,surface-doped Ag_(4)M_(2)(SR)_(8) and core-doped Ag_(24)M(SR)_(18)(M=Ni,Pd,Pt;SR=SPhMe_(2))NCs were synthesized for electrocatalytic GLY oxidation.The results revealed a strong dependence of selectivity on doping mode and electrolyte concentration:under low KOH concentration,Pd-and Pt-doped Ag_(4)M_(2) NCs exhibited 100%selectivity toward oxalic acid(OA),whereas Pd-and Pt-doped Ag_(24)M NCs delivered>95%selectivity for formic acid(FA).In contrast,under high KOH concentration,Pd-and Pt-doped Ag_(4)M_(2) NCs gave rise to>80%FA,while Pd-and Pt-doped Ag_(24)M NCs produced>45%FA.Mechanism studies indicated that Ni doping predominantly enhanced catalytic activity via lowering the activation barrier of the initial reaction step(GLY→glyceraldehyde),whereas Pd and Pt doping modulated selectivity through reducing the energy barrier of the selective branch step(glyceric acid→OA,OA→FA).High KOH concentration promoted the oxidation by increasing the electrochemical active surface area and facilitating electron transfer of Ag NCs.This study provides clear guidance for designing high-performance Ag-based electrocatalysts for biomass valorization.展开更多
In the lattice system,when the synthetic flux reaches aπphase along a closed loop under the synthetic gauge field,destructive interference occurs and gives rise to the localization phenomenon.This is known as the Aha...In the lattice system,when the synthetic flux reaches aπphase along a closed loop under the synthetic gauge field,destructive interference occurs and gives rise to the localization phenomenon.This is known as the Aharonov-Bohm(AB)caging effect.It provides a powerful tool for the study of quantum transport and dynamical effects.In the system where lattice sites possess internal structure and the underlying gauge field is non-Abelian,localization can also occur,forming the non-Abelian AB caging.Here,we propose an experimental scheme to synthesize non-Abelian gauge fields with a single trapped ion by coupling multiple internal levels and Fock states in its motion via laser fields.In contrast to the Abelian AB caging,we numerically observe that the non-Abelian AB caging occurs either when the interference matrix is nilpotent,or when the initial state is specifically set.Our experimental scheme broadens the study of localization phenomena and provides a novel tool for the study of non-Abelian physics.展开更多
The UV-2600 ultraviolet(UV)spectrophotometer and the UV sunscreen index analyzer SolarLight Model 601 were used to test the UV absorption capacity and the UV damage alleviating effect of commonly used raw materials,an...The UV-2600 ultraviolet(UV)spectrophotometer and the UV sunscreen index analyzer SolarLight Model 601 were used to test the UV absorption capacity and the UV damage alleviating effect of commonly used raw materials,and the Hen’s Egg Test-Chorioallantoic Membrane were also processed to assess the mildness.As a result,bisabolol,pongamia pinnata seed extract,pterocarpus marsupium bark extract and other materials were screened as the effective and gentle sunscreen synergistic ingredients.展开更多
The dried fruit of Forsythia suspensa(Oleaceae),also known as Forsythia,is a traditional Chinese medicinal herb known for its heat-clearing and detoxifying properties.It is used to disperse nodules,reduce swelling,rem...The dried fruit of Forsythia suspensa(Oleaceae),also known as Forsythia,is a traditional Chinese medicinal herb known for its heat-clearing and detoxifying properties.It is used to disperse nodules,reduce swelling,remove toxins,clear heat,and alleviate wind-heat syndromes.It also has hepatoprotective,anti-inflammatory,antiviral,antibacterial,anticancer,antioxidant,antiaging,and anti-obesity effects,as well as potential therapeutic effects on Alzheimer’s disease and diabetic nephropathy.It is used to treat scrofula,mastitis,wind-heat common cold,and other ailments.The review summarizes the chemical constituents and pharmacological effects of F.suspensa,aiming to provide a scientific foundation for its future development,research,and clinical utilization.展开更多
The Zeeman effect,a fundamental quantum phenomenon,demonstrates the interaction between magnetic fields and atomic systems.While precise spectroscopic measurements of this effect have advanced significantly,there rema...The Zeeman effect,a fundamental quantum phenomenon,demonstrates the interaction between magnetic fields and atomic systems.While precise spectroscopic measurements of this effect have advanced significantly,there remains a lack of simple,visually accessible demonstration for educational purposes.Here,we present a low-cost experiment that allows for direct visual observation of the Zeeman effect.Our setup involves a flame containing sodium(from table salt)placed in front of a sodium vapor lamp.When a magnetic field is applied to the flame,the shadow cast by the flame noticeably lightens,providing a clear,naked-eye demonstration of the Zeeman effect.Furthermore,we conduct two quantitative experiments using this setup,examining the effects of varying magnetic field strength and sodium concentration.This innovative approach not only enriches the experimental demonstration for teaching atomic physics at undergraduate and high school levels but also provides an open platform for students to explore the Zeeman effect through hands-on experience.展开更多
Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based met...Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based methods,tracking on a single CPU core,or parallelizing the computation across multiple cores via the message passing interface(MPI).Although these approaches work well for single-bunch tracking,scaling them to multiple bunches significantly increases the computational load,which often necessitates the use of a dedicated multi-CPU cluster.To address this challenge,alternative methods leveraging General-Purpose computing on Graphics Processing Units(GPGPU)have been proposed,enabling tracking studies on a standalone desktop personal computer(PC).However,frequent CPU-GPU interactions,including data transfers and synchronization operations during tracking,can introduce communication overheads,potentially reducing the overall effectiveness of GPU-based computations.In this study,we propose a novel approach that eliminates this overhead by performing the entire tracking simulation process exclusively on the GPU,thereby enabling the simultaneous processing of all bunches and their macro-particles.Specifically,we introduce MBTRACK2-CUDA,a Compute Unified Device Architecture(CUDA)ported version of MBTRACK2,which facilitates efficient tracking of single-and multi-bunch collective effects by leveraging the full GPU-resident computation.展开更多
Kagome magnets are of growing interest due to their topological electronic structures and unconventional magnetic behavior.Here,we report on the anomalous Hall effect(AHE)in the kagome ferromagnet MgMn_(6)Sn_(6),which...Kagome magnets are of growing interest due to their topological electronic structures and unconventional magnetic behavior.Here,we report on the anomalous Hall effect(AHE)in the kagome ferromagnet MgMn_(6)Sn_(6),which has a Curie temperature of~290 K and an in-plane easy magnetization axis.Magnetotransport measurements show a positive magnetoresistance(MR)below 50 K,which becomes negative at higher temperatures.An intrinsic anomalous Hall conductivity of 114 S·cm^(-1)is observed in MgMn_(6)Sn_(6) single crystals,consistent with ab initio calculations.Moreover,theoretical predictions indicate that shifting the Fermi level(EF)upward by~70 meV could enhance the AHE to~528 S·cm^(-1).These results position MgMn_(6)Sn_(6) as a promising and tunable platform for exploring topological magnetism and related electronic phenomena.展开更多
基金supported by Science and Technology Foundation of Beijing Jiaotong University (Grant No 2005sm058)
文摘There are two different viewpoints on the Aharonov-Bohm （A-B） effect. One asserts that the A-B effect is due to the existence of the vector potential A. The other asserts that the A-B effect is due to the interaction energy between the magnetic field produced by the moving charges and the magnetic field in the solenoid. The difference of these two viewpoints is analyzed in this paper. To judge which viewpoint is right, this paper suggests a new experimental method.
文摘Invariant operator method for discrete or continuous spectrum eigenvalue and unitary transformation approach are employed to study the two-dimensional time-dependent Pauli equation in presence of the Aharonov-Bohm effect （AB） and external scalar potential. For the spin particles the problem with the magnetic field is that it introduces a singularity into wave equation at the origin. A physical motivation is to replace the zero radius flux tube by one of radius R, with the additional condition that the magnetic field be confined to the surface of the tube, and then taking the limit R → 0 at the end of the computations. We point that the invariant operator must contain the step function θ（r - R）. Consequently, the problem becomes more complicated. In order to avoid this dimculty, we replace the radius R by ρ（t）R, where ρ（t） is a positive time-dependent function. Then at the end of calculations we take the limit R →0. The qualitative properties for the invariant operator spectrum are described separately for the different values of the parameter C appearing in the nonlinear auxiliary equation satisfied by p（t）, i.e., C 〉 0, C = 0, and C 〈0. Following the C＇s values the spectrum of quantum states is discrete （C 〉 0） or continuous （C ≤ 0）.
基金Supported by the Algerian Ministry of Higher Education and Scientific Research(MESRS)
文摘The 2D Pauli equation with Hulthen potential for spin-1/2 particle in the presence of Aharonov-Bohm （AB） field is solved analytically, on the assumption that an effective approximation is used for the centrifugal term. Singular and regular solutions of the problem are obtained. It is shown that the AB field lifts the degeneracy of the energy levels. The range of the flux parameter for which singular solutions are allowed is modified compared to the pure AB case. When the screening parameter vanishes, it is shown that the obtained energy spectrum becomes the same as that of the Aharonov-Bohm Coulomb problem.
文摘The relativistic Aharonov-Bohm (AB) effect is studied using the time-dependent Dirac equation. It is shown that if the initial electron distribution is a pulse it is possible to define time-dependent signals that distinguish the AB effect from dipole and induced Coulomb interactions.
文摘This article shows that in Aharonov-Bohm (AB) effect arrangements, the electron wave propagation space is doubly connected for two real coherent sources, and simply connected under certain condition for two virtual coherent sources, and all known AB experiments belong to the latter case. By the Feynman path integral method, we show that in the former case there is no AB effect, whereas in the latter case there is.
文摘The AB(Aharonov-Bohm)effect is a pivotal quantum mechanical phenomenon that illustrates the fundamental role of the electromagnetic vector potential A in determining the phase of a charged particle’s wave function,even in regions where the magnetic field B is zero.This effect demonstrates that quantum particles are influenced not only by the fields directly present but also by the potentials associated with those fields.In the AB effect,an electron beam is split into two paths,with one path encircling a solenoid and the other bypassing it.Despite the absence of a magnetic field in the regions traversed by the beams,the vector potential A associated with the magnetic flux Φ through the solenoid induces a phase shift in the electron’s wave function.This phase shift,quantified by △φ=qΦ/hc,manifests as a change in the interference pattern observed in the detection screen.The phenomenon underscores the principle of gauge invariance in QED(quantum electrodynamics),where physical observables remain invariant under local gauge transformations of the vector and scalar potentials.This reinforces the notion that the vector potential A has a profound impact on quantum systems,beyond its classical role.This article outlines the AB effect,including its theoretical framework,experimental observations,and implications.The focus on the role of the vector potential in quantum mechanics provides a comprehensive understanding of this important phenomenon.
基金the support provided by the National Natural Science Foundation of China(92165107)the fundamental research program of the Chinese Academy of Sciences,the China Manned Space Engineering Office,and the National Key R&D Program of China(2016YFA0301504).
文摘The gravitational Aharonov-Bohm(GAB)effect serves as the gravitational counterpart to the electromagnetic Aharonov-Bohm effect.Despite the concept’s inception in 1967,a rigorous experimental test of the GAB effect remains elusive.While recent endeavors with ground-based apparatus show promise in uncovering hints of the GAB effect,we propose a precise yet practical experiment to deterministically measure the GAB phase shift using cold atom interferometry in a microgravity environment,such as an orbital space station or drop tower.We conduct a thorough analysis of the experiment’s principles and derive key parameters.Our calculations suggest that it is feasible to precisely measure a significant GAB phase shift within known engineering constraints.Additionally,our design of the cold atom interferometer possesses a unique sensitivity to potential but insensitivity to force,which can be further refined to effectively mitigate adverse effects associated with nonzero inertial forces acting on the cold atoms.These endeavors will ultimately pave the way for experimental exploration into the quantum nature of gravity.
基金supported by the National Natural Science Foundation of China(12275136 and 12075001)the 111 Project of B23045supported by the Nankai Zhide Foundations.
文摘The Aharonov-Bohm(AB)effect is an important discovery of quantum theory.It serves as a surprising quantum phenomenon in which an electrically charged particle can be affected by an electromagnetic potential,despite being confined to a region in which both the magnetic field and electric field are zero.This fact gives the electromagnetic potentials greater significance in quantum physics than in classical physics.The original AB effect belongs to an“electromagnetic type”.A certain vector potential is crucial for building a certain type of AB effect.In this work,we focus on the“spin”,which is an intrinsic property of microscopic particles that has been widely accepted nowadays.First,we propose the hypothesis of spin vector potential by considering a particle with a spin operator.Second,to verify the existence of such a spin vector potential,we present a gedanken double-slit interference experiment(i.e.,the spin AB effect),which is possible to be observed in the lab.Third,we apply the spin vector potential to naturally explain why there were the Dzyaloshinsky-Moriya-type interaction and the dipole-dipole interaction between spins,and also predict a new type of spin-orbital interaction.
文摘Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms ligand bonds or hydrogen bonds with sulfur ions in lithium polysulfides(LiPSs),thus inhibiting the shuttle effect.Electrochemical analyses demonstrated that lithium‑sulfur(Li‑S)batteries employing the NH2‑SS interlayer exhibited discharge specific capacities of 1048 and 789 mAh·g^(-1) at 0.2C and 2C,respectively,and even at 4C,the initial discharge specific capacity remained at 590 mAh·g^(-1),outperforming the Li‑S battery with unmodified SS as the interlayer.
基金National Natural Science Foundation of China(11875039)Shanxi Scholarship Council of China(2023-033)+2 种基金Fundamental Research Program of Shanxi Province(202303021221071)China Baowu Low Carbon Metallurgical Innovation Foundation(2022)2023 Anhui Major Industrial Innovation Plan Project。
文摘The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.
基金supported by the National Natural Science Foundation of China“Research on the Multi-scale Regional Industrial Spatial Evolution Mechanism,Resource and Environmental Effects,and Green Transformation in the Yellow River Basin”[Grant No.42371194]Taishan Scholar Foundation of Shandong Province[Grant Nos.tsqn202408148 and tstp20240821].
文摘Agglomeration supports the high-quality development of the manufacturing industry,and its associated resource and environmental effects play a crucial role in driving green economic development.Based on data from prefecture-level cities in China from 2005 to 2019,this study employs the inverse distance weighting method,the bivariate local indicator of spatial association model,the spatial Durbin model,and other techniques to explore the relationship between manufacturing agglomeration and PM_(2.5)concentrations,and to assess the impact of its manufacturing agglomeration.Four correlation patterns are observed:high-high,low-low,high-low,and low-high.Among these,high-high and low-low patterns dominate in terms of number of cities.These correlation patterns demonstrate strong temporal stability,with a clear“Matthew effect”.The effect of manufacturing agglomeration on PM_(2.5)levels is significantly negative and helps reduce concentrations regionally,indicating the need to further enhance agglomeration levels regionally.However,it can increase PM_(2.5)levels in neighboring areas due to a siphon effect,and the impact of varies across regions.Compared with levels in 2005-2013,the significance of the relationship between manufacturing agglomeration and PM_(2.5)weakened in the 2013-2019 period.Accordingly,this study proposes countermeasures and policy recommendations aimed at strengthening regional collaborative governance and inspiring differentiated agglomeration strategies to support sustainable economic development in China.
文摘Chitosan(CTS)was grafted onto the surface of amino‑functionalized silver chloride silicon dioxide(AgCl@SiO_(2)‑NH_(2))cores to obtain AgCl@SiO_(2)/CTS hybrid nanoparticles.The as‑obtained AgCl@SiO_(2)/CTS nanoparticles were chlorinated by NaClO solution to get AgCl@SiO_(2)/CTS‑based chloramine nano‑hybrid materials,denoted as AgCl@SiO_(2)/CTS‑Cl.A transmission electron microscope was used to observe the morphology of the as‑prepared samples AgCl@SiO_(2)/CTS and AgCl@SiO_(2)/CTS‑Cl.At the same time,an X‑ray diffractometer and an infrared spectroscope were utilized to characterize their crystal and chemical structures.Besides,ζpotentials were measured to elucidate the surface modification of AgCl nanoparticles by—NH_(2),the antibacterial mechanism of AgCl@SiO_(2)/CTS‑Cl was investigated by scanning electron microscopy,and Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were used as the to‑be‑tested strains to evaluate the antimicrobial activity of samples AgCl@SiO_(2)/CTS and AgCl@SiO_(2)/CTS‑Cl.Findings demonstrate that sample AgCl@SiO_(2)/CTS exhibits a chain‑like structure ascribed to the interaction between—NH_(2),and each AgCl@SiO_(2)/CTS hybrid nanoparticle contains several AgCl cores.In the meantime,sample AgCl@SiO_(2)/CTS‑Cl exhibits excellent antibacterial activity against E.coli and S.aureus,which is attributed to the synergistic antibacterial effect of Ag^(+)and Cl^(-).Sample AgCl@SiO_(2)/CTS‑Cl with a dosage of 640.00μg·mL^(-1) could completely kill the two kinds of tested bacteria in 12 h of incubation;it retains a high antibacterial efficiency even after 10 cycles of antibacterial tests.
基金supported by the National Natural Science Foundation of China(No.62464010)Spring City Plan-Special Program for Young Talents(K202005007)+2 种基金Yunnan Talents Support Plan for Young Talents(XDYC-QNRC-2022-0482)Yunnan Local Colleges Applied Basic Research Projects(202101BA070001-138)Frontier Research Team of Kunming University 2023.
文摘Rechargeable Zn/Sn-air batteries have received considerable attention as promising energy storage devices.However,the electrochemical performance of these batteries is significantly constrained by the sluggish electrocatalytic reaction kinetics at the cathode.The integration of light energy into Zn/Sn-air batteries is a promising strategy for enhancing their performance.However,the photothermal and photoelectric effects generate heat in the battery under prolonged solar irradiation,leading to air cathode instability.This paper presents the first design and synthesis of Ni_(2)-1,5-diamino-4,8-dihydroxyanthraquinone(Ni_(2)DDA),an electronically conductiveπ-d conjugated metal-organic framework(MOF).Ni_(2)DDA exhibits both photoelectric and photothermal effects,with an optical band gap of~1.14 eV.Under illumination,Ni_(2)DDA achieves excellent oxygen evolution reaction performance(with an overpotential of 245 mV vs.reversible hydrogen electrode at 10 mA cm^(−2))and photothermal stability.These properties result from the synergy between the photoelectric and photothermal effects of Ni_(2)DDA.Upon integration into Zn/Sn-air batteries,Ni_(2)DDA ensures excellent cycling stability under light and exhibits remarkable performance in high-temperature environments up to 80℃.This study experimentally confirms the stable operation of photo-assisted Zn/Sn-air batteries under high-temperature conditions for the first time and provides novel insights into the application of electronically conductive MOFs in photoelectrocatalysis and photothermal catalysis.
基金support from the Jiangsu Natural Science Foundation of China(BK20230329)the National Natural Science Foundation of China(22401147,22361132540,and 22178161)the Russian Science Foundation(23-73-30007).
文摘The efficient electrocatalytic oxidation of glycerol(GLY)is one of the most promising routes for the valorization of GLY.Doping has emerged as a powerful strategy to tailor the electrocatalytic performance of silver nanoclusters(Ag NCs),yet the effects of doping mode(surface vs.core)and the interface environment(e.g.,electrolyte concentration)on the electrocatalytic performance for Ag NCs toward GLY oxidation remain understood.In this work,surface-doped Ag_(4)M_(2)(SR)_(8) and core-doped Ag_(24)M(SR)_(18)(M=Ni,Pd,Pt;SR=SPhMe_(2))NCs were synthesized for electrocatalytic GLY oxidation.The results revealed a strong dependence of selectivity on doping mode and electrolyte concentration:under low KOH concentration,Pd-and Pt-doped Ag_(4)M_(2) NCs exhibited 100%selectivity toward oxalic acid(OA),whereas Pd-and Pt-doped Ag_(24)M NCs delivered>95%selectivity for formic acid(FA).In contrast,under high KOH concentration,Pd-and Pt-doped Ag_(4)M_(2) NCs gave rise to>80%FA,while Pd-and Pt-doped Ag_(24)M NCs produced>45%FA.Mechanism studies indicated that Ni doping predominantly enhanced catalytic activity via lowering the activation barrier of the initial reaction step(GLY→glyceraldehyde),whereas Pd and Pt doping modulated selectivity through reducing the energy barrier of the selective branch step(glyceric acid→OA,OA→FA).High KOH concentration promoted the oxidation by increasing the electrochemical active surface area and facilitating electron transfer of Ag NCs.This study provides clear guidance for designing high-performance Ag-based electrocatalysts for biomass valorization.
基金supported by the National Natural Science Foundation of China(Grant Nos.92165206,12275090,and 12304554)the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0301603 and 2021ZD0302303)。
文摘In the lattice system,when the synthetic flux reaches aπphase along a closed loop under the synthetic gauge field,destructive interference occurs and gives rise to the localization phenomenon.This is known as the Aharonov-Bohm(AB)caging effect.It provides a powerful tool for the study of quantum transport and dynamical effects.In the system where lattice sites possess internal structure and the underlying gauge field is non-Abelian,localization can also occur,forming the non-Abelian AB caging.Here,we propose an experimental scheme to synthesize non-Abelian gauge fields with a single trapped ion by coupling multiple internal levels and Fock states in its motion via laser fields.In contrast to the Abelian AB caging,we numerically observe that the non-Abelian AB caging occurs either when the interference matrix is nilpotent,or when the initial state is specifically set.Our experimental scheme broadens the study of localization phenomena and provides a novel tool for the study of non-Abelian physics.
文摘The UV-2600 ultraviolet(UV)spectrophotometer and the UV sunscreen index analyzer SolarLight Model 601 were used to test the UV absorption capacity and the UV damage alleviating effect of commonly used raw materials,and the Hen’s Egg Test-Chorioallantoic Membrane were also processed to assess the mildness.As a result,bisabolol,pongamia pinnata seed extract,pterocarpus marsupium bark extract and other materials were screened as the effective and gentle sunscreen synergistic ingredients.
文摘The dried fruit of Forsythia suspensa(Oleaceae),also known as Forsythia,is a traditional Chinese medicinal herb known for its heat-clearing and detoxifying properties.It is used to disperse nodules,reduce swelling,remove toxins,clear heat,and alleviate wind-heat syndromes.It also has hepatoprotective,anti-inflammatory,antiviral,antibacterial,anticancer,antioxidant,antiaging,and anti-obesity effects,as well as potential therapeutic effects on Alzheimer’s disease and diabetic nephropathy.It is used to treat scrofula,mastitis,wind-heat common cold,and other ailments.The review summarizes the chemical constituents and pharmacological effects of F.suspensa,aiming to provide a scientific foundation for its future development,research,and clinical utilization.
基金the National Natural Science Foundation of China for support under grant No.12305037the Fundamental Research Funds for the Central Universities under grant No.2023NTST017。
文摘The Zeeman effect,a fundamental quantum phenomenon,demonstrates the interaction between magnetic fields and atomic systems.While precise spectroscopic measurements of this effect have advanced significantly,there remains a lack of simple,visually accessible demonstration for educational purposes.Here,we present a low-cost experiment that allows for direct visual observation of the Zeeman effect.Our setup involves a flame containing sodium(from table salt)placed in front of a sodium vapor lamp.When a magnetic field is applied to the flame,the shadow cast by the flame noticeably lightens,providing a clear,naked-eye demonstration of the Zeeman effect.Furthermore,we conduct two quantitative experiments using this setup,examining the effects of varying magnetic field strength and sodium concentration.This innovative approach not only enriches the experimental demonstration for teaching atomic physics at undergraduate and high school levels but also provides an open platform for students to explore the Zeeman effect through hands-on experience.
基金supported by the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(MSIT)(No.RS-2022-00143178)the Ministry of Education(MOE)(Nos.2022R1A6A3A13053896 and 2022R1F1A1074616),Republic of Korea.
文摘Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based methods,tracking on a single CPU core,or parallelizing the computation across multiple cores via the message passing interface(MPI).Although these approaches work well for single-bunch tracking,scaling them to multiple bunches significantly increases the computational load,which often necessitates the use of a dedicated multi-CPU cluster.To address this challenge,alternative methods leveraging General-Purpose computing on Graphics Processing Units(GPGPU)have been proposed,enabling tracking studies on a standalone desktop personal computer(PC).However,frequent CPU-GPU interactions,including data transfers and synchronization operations during tracking,can introduce communication overheads,potentially reducing the overall effectiveness of GPU-based computations.In this study,we propose a novel approach that eliminates this overhead by performing the entire tracking simulation process exclusively on the GPU,thereby enabling the simultaneous processing of all bunches and their macro-particles.Specifically,we introduce MBTRACK2-CUDA,a Compute Unified Device Architecture(CUDA)ported version of MBTRACK2,which facilitates efficient tracking of single-and multi-bunch collective effects by leveraging the full GPU-resident computation.
基金Project supported by the National Natural Science Foundation of China(Grant No.12204347)National Key Research and Development Program of China(Grant No.2022YFA1402600)the Fund from Beijing National Laboratory for Condensed Matter Physics(Grant No.2023BNLCMPKF011)。
文摘Kagome magnets are of growing interest due to their topological electronic structures and unconventional magnetic behavior.Here,we report on the anomalous Hall effect(AHE)in the kagome ferromagnet MgMn_(6)Sn_(6),which has a Curie temperature of~290 K and an in-plane easy magnetization axis.Magnetotransport measurements show a positive magnetoresistance(MR)below 50 K,which becomes negative at higher temperatures.An intrinsic anomalous Hall conductivity of 114 S·cm^(-1)is observed in MgMn_(6)Sn_(6) single crystals,consistent with ab initio calculations.Moreover,theoretical predictions indicate that shifting the Fermi level(EF)upward by~70 meV could enhance the AHE to~528 S·cm^(-1).These results position MgMn_(6)Sn_(6) as a promising and tunable platform for exploring topological magnetism and related electronic phenomena.
