Recently,large-scale trapped ion systems have been realized in experiments for quantum simulation and quantum computation.They are the simplest systems for dynamical stability and parametric resonance.In this model,th...Recently,large-scale trapped ion systems have been realized in experiments for quantum simulation and quantum computation.They are the simplest systems for dynamical stability and parametric resonance.In this model,the Mathieu equation plays the most fundamental role for us to understand the stability and instability of a single ion.In this work,we investigate the dynamics of trapped ions with the Coulomb interaction based on the Hamiltonian equation.We show that the many-body interaction will not influence the phase diagram for instability.Then,the dynamics of this model in the large damping limit will also be analytically calculated using few trapped ions.Furthermore,we find that in the presence of modulation,synchronization dynamics can be observed,showing an exchange of velocities between distant ions on the left side and on the right side of the trap.These dynamics resemble that of the exchange of velocities in Newton's cradle for the collision of balls at the same time.These dynamics are independent of their initial conditions and the number of ions.As a unique feature of the interacting Mathieu equation,we hope this behavior,which leads to a quasi-periodic solution,can be measured in current experimental systems.Finally,we have also discussed the effect of anharmonic trapping potential,showing the desynchronization during the collision process.It is hoped that the dynamics in this many-body Mathieu equation with damping may find applications in quantum simulations.This model may also find interesting applications in dynamics systems as a pure mathematical problem,which may be beyond the results in the Floquet theorem.展开更多
We study the production of the X(6900)in the ultra-peripheral heavy ion collisions at the LHC energy region.The potential quantum numbers of X(6900)could be 0^(±+)and 2^(±+).We find that the transverse momen...We study the production of the X(6900)in the ultra-peripheral heavy ion collisions at the LHC energy region.The potential quantum numbers of X(6900)could be 0^(±+)and 2^(±+).We find that the transverse momentum and the polar angle distributions of X(6900)can be used to distinguish these four potential quantum numbers.These characteristic distributions originate from linearly polarized photons emitted by relativistic nuclei and can be measured by further LHC experiments.展开更多
Based on the data of meteorological elements and concentration of negative ions in the county town station,Luguhe station and Yunjishan station during 2020-2024,the temporal and spatial variations in the concentration...Based on the data of meteorological elements and concentration of negative ions in the county town station,Luguhe station and Yunjishan station during 2020-2024,the temporal and spatial variations in the concentration of negative ions and their influencing factors in Xinfeng County were analyzed.The results show that the concentration of negative ions was the highest in summer,followed by spring;it was lower in autumn and the lowest in winter.In terms of diurnal variations,it was higher in the early morning and night,and lower in the noon and afternoon,which was closely related to the diurnal variations of human activities and meteorological conditions.The factors that affect the concentration of negative ions in the air are more complex.Besides meteorological factors,vegetation,altitude,human activities and other factors should be considered.展开更多
The combined reagents of sodium N-oleoylsarcosinate(SNOS)with metal ions(Ca(Ⅱ),Mg(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ))was employed to facilitate the separation of lepidolite from feldspar.The synergistic interaction mechanism of t...The combined reagents of sodium N-oleoylsarcosinate(SNOS)with metal ions(Ca(Ⅱ),Mg(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ))was employed to facilitate the separation of lepidolite from feldspar.The synergistic interaction mechanism of this combined reagent was systematically investigated via contact angle measurements,AFM,FTIR,species distribution calculations,and DFT calculations.The results suggested that Ca(Ⅱ)exhibited the best selectivity for activating lepidolite flotation.SNOS was chemically adsorbed on the Ca(Ⅱ)-activated lepidolite surface with an adsorption energy of−1248.91 kJ/mol while a lower adsorption energy of−598.84 kJ/mol of SNOS on Ca(Ⅱ)-activated feldspar was calculated.Therefore,this combination of SNOS and Ca(Ⅱ)is a promising reagent scheme for the efficient recovery of lithium from aluminosilicate ore.展开更多
Gallium nitride(GaN)-based devices have significant potential for space applications.However,the mechanisms of radiation damage to the device,particularly from strong ionizing radiation,remains unknown.This study inve...Gallium nitride(GaN)-based devices have significant potential for space applications.However,the mechanisms of radiation damage to the device,particularly from strong ionizing radiation,remains unknown.This study investigates the effects of radiation on p-gate AlGaN/GaN high-electron-mobility transistors(HEMTs).Under a high voltage,the HEMT leakage current increased sharply and was accompanied by a rapid increase in power density that caused"thermal burnout"of the devices.In addition,a burnout signature appeared on the surface of the burned devices,proving that a single-event burnout effect occurred.Additionally,degradation,including an increase in the on-resistance and a decrease in the breakdown voltage,was observed in devices irradiated with high-energy heavy ions and without bias.The latent tracks induced by heavy ions penetrated the heterojunction interface and extended into the GaN layer.Moreover,a new type of N_(2)bubble defect was discovered inside the tracks using Fresnel analysis.The accumulation of N_(2)bubbles in the heterojunction and buffer layers is more likely to cause leakage and failure.This study indicates that electrical stress accelerates the failure rate and that improving heat dissipation is an effective reinforcement method for GaN-based devices.展开更多
One of the detection objectives of the Chinese Asteroid Exploration mission is to investigate the space environment near the Main-belt Comet(MBC,Active Asteroid)311P/PANSTARRS.This paper outlines the scientific object...One of the detection objectives of the Chinese Asteroid Exploration mission is to investigate the space environment near the Main-belt Comet(MBC,Active Asteroid)311P/PANSTARRS.This paper outlines the scientific objectives,measurement targets,and measurement requirements for the proposed Gas and Ion Analyzer(GIA).The GIA is designed for in-situ mass spectrometry of neutral gases and low-energy ions,such as hydrogen,carbon,and oxygen,in the vicinity of 311P.Ion sampling techniques are essential for the GIA's Time-of-Flight(TOF)mass analysis capabilities.In this paper,we present an enhanced ion sampling technique through the development of an ion attraction model and an ion source model.The ion attraction model demonstrates that adjusting attraction grid voltage can enhance the detection efficiency of low-energy ions and mitigate the repulsive force of ions during sampling,which is influenced by the satellite's surface positive charging.The ion source model simulates the processes of gas ionization and ion multiplication.Simulation results indicate that the GIA can achieve a lower pressure limit below 10-13Pa and possess a dynamic range exceeding 10~9.These performances ensure the generation of ions with stable and consistent current,which is crucial for high-resolution and broad dynamic range mass spectrometer analysis.Preliminary testing experiments have verified GIA's capability to detect gas compositions such as H2O and N2.In-situ measurements near 311P using GIA are expected to significantly contribute to our understanding of asteroid activity mechanisms,the evolution of the atmospheric and ionized environments of main-belt comets,the interactions with solar wind,and the origin of Earth's water.展开更多
The extracellular polymeric substances（EPS） of Acidithiobacillus ferrooxidans ATCC 23270,and iron and copper enclosed in EPS were extracted by ultrasonication and centrifugation methods to determine the interaction ...The extracellular polymeric substances（EPS） of Acidithiobacillus ferrooxidans ATCC 23270,and iron and copper enclosed in EPS were extracted by ultrasonication and centrifugation methods to determine the interaction mechanism of Cu2＋,Fe3＋ and EPS during bioleaching chalcopyrite.Generally,Cu2＋ ions can stimulate bacteria to produce more EPS than Fe3＋ ions.The mass ratio of Fe3＋/Cu2＋ enclosed in EPS decreased gradually from about 4：1 to about 2：1 when the concentration of Cu2＋ ions increased from 0.01 to 0.04 mol/L.The amount of iron and copper bound together by EPS in ferrous-free 9K medium containing 1% chalcopyrite was about 2 times of that in 9K medium containing 0.04 mol/L Cu2＋ ions.It was inferred that the EPS with jarosites on the surface of chalcopyrite gradually acted as a weak diffusion barrier for Cu2＋,Fe3＋ ions transference during bioleaching chalcopyrite.展开更多
The effects of copper ions and calcium ions on the depression of chlorite using CMC（carboxymethyl cellulose） as a depressant were studied through flotation tests,adsorption measurements,ζ potential tests and co-pre...The effects of copper ions and calcium ions on the depression of chlorite using CMC（carboxymethyl cellulose） as a depressant were studied through flotation tests,adsorption measurements,ζ potential tests and co-precipitation experiments.The results show that the electrostatic repulsion between the CMC molecules and the chlorite surfaces hinders the approach of the CMC to the chlorite while the presence of copper ions and calcium ions enhances the adsorption density of CMC.The action mechanisms of these two types of ions are different.Calcium ions can not adsorb onto the mineral surfaces,but they can interact with the CMC molecules,thus reducing the charge of the CMC and enhancing adsorption density.Copper ions can adsorb onto the mineral surfaces,which facilitates the CMC adsorption through acid/base interaction.The enhanced adsorption density is also attributed to the decreased electrostatic repulsion between the CMC and mineral surfaces as copper ions reduce the surface charge of both the mineral surfaces and the CMC molecules.展开更多
To address the temperature cross-talk issue in detecting heavy metal ions in natural waters, a highly-integrated and fully fiber-optic metal ion sensing system capable of temperature-concentration decoupling measureme...To address the temperature cross-talk issue in detecting heavy metal ions in natural waters, a highly-integrated and fully fiber-optic metal ion sensing system capable of temperature-concentration decoupling measurement has been designed. This system integrates a fluidic detection structure assisted by side-polished fibers(SPFs) with a Sagnac interferometer.展开更多
The nano-MOF-303 synthesized by microwave method exhibited efficient adsorption capacity(232 mg/g)toward Ag^(+),in which the adsorption behaviors were fitted by the pseudo-second-order kinetic and the Freundlich isoth...The nano-MOF-303 synthesized by microwave method exhibited efficient adsorption capacity(232 mg/g)toward Ag^(+),in which the adsorption behaviors were fitted by the pseudo-second-order kinetic and the Freundlich isotherm model.The outstanding Ag^(+)sorption ability of nano-MOF-303 could be contributed to electrostatic interactions,weak coordination interaction of Ag-N,and Ag Cl precipitates originating from the stored Cl^(-)in nano-MOF-303.Besides the adsorbent regeneration,the formed Ag/Ag Cl onto nano-MOF-303 could produce Ag/Ag Cl/MOF-303 as a photocatalyst for sulfamethoxazole degradation under visible light.In this work,both the adsorption and photocatalysis mechanisms were clarified,which might provide insight to develop more effective adsorbents for mining the critical resource from the wastewater.展开更多
Ti6Al4V alloy has been widely used in dental applications,such as orthodontic mini-implants.However,it has been reported that fluoride ions could obviously accelerate the corrosion of implant materials and affect thei...Ti6Al4V alloy has been widely used in dental applications,such as orthodontic mini-implants.However,it has been reported that fluoride ions could obviously accelerate the corrosion of implant materials and affect their performance.This work aimed to improve the F^(−)erosion resistance of Ti6Al4V alloy through the strategy of both Cu addition and grain refinement.As contrasted with Ti6Al4V alloy,both the coarse-and ultrafine-grained Ti6Al4V-5Cu alloys effectively mitigated the acceleration of the fluoride ions to the anode process,because Cu substituents blocked the continuous damage of F·_(O) doped in the passive film.Furthermore,grain refinement enhanced the protective ability of the passive film,more oxides and less adsorption amount of fluorides presented in the passive film of ultrafine-grained Ti6Al4V-5Cu alloy than those of coarse-grained Ti6Al4V-5Cu alloy.Under the combination of Cu alloying and grain refinement,the ultrafine-grained Ti6Al4V-5Cu alloy is greatly appropriate for the fabrication of orthodontic devices.展开更多
The in-depth study of the transport properties of the solid electrolyte interface(SEI)is crucial for the development of ultra-high-rate,and long lifespan sodium-ion batteries(SIBs).However,there remains a lack of theo...The in-depth study of the transport properties of the solid electrolyte interface(SEI)is crucial for the development of ultra-high-rate,and long lifespan sodium-ion batteries(SIBs).However,there remains a lack of theoretical investigation into the transport mechanisms of the main inorganic components of the SEI,namely Na F,Na_(2)O,and Na_(2)CO_(3).To address this research gap,we performed classical molecular dynamics simulations in this work to study the diffusion mechanisms of sodium ions in these inorganic components of the SEI,with special emphasis on the impact of the amorphous SEI environment on the diffusion behavior of sodium ions.The results have shown that amorphous SEI components significantly enhance the diffusion rate of sodium ions at room temperature compared to crystalline components.Within these amorphous SEI components,we reveal that the diffusion coefficients of sodium ions in amorphous Na_(2)O and Na_(2)CO_(3)are more than an order of magnitude higher than that of Na F,suggesting that amorphous Na_(2)O and Na_(2)CO_(3)are more effective in facilitating the Na ion diffusion.Analysis of the local atomic structure indicates that the amorphous local structures are dominant in Na_(2)O and Na_(2)CO_(3)at room temperature,maintaining a disordered amorphous phase.In contrast,amorphous Na F undergoes a spontaneously transformation into an ordered structure,exhibiting crystalline characteristics that restrict the diffusion of sodium ions.In summary,our work provides atomic insights into the impact of local amorphous environments on Na ion diffusion in SEI and suggests that amorphous SEI components play a critical role in improving battery performance.展开更多
Here,the effect of cerium and terbium ions substitution on structural,optical,dielectric,and electrical properties of Ca_(0.95)Y_(0.05)Fe_(12)O_(19)M-type hexaferrite prepared by solvent free method i.e.,auto co mbust...Here,the effect of cerium and terbium ions substitution on structural,optical,dielectric,and electrical properties of Ca_(0.95)Y_(0.05)Fe_(12)O_(19)M-type hexaferrite prepared by solvent free method i.e.,auto co mbustion method was reported.The X-ray diffraction technique was used for the structural examination.The hexagonal structure of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples is confirmed by X-ray diffraction(XRD)pattern analysis.The crystallite size of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)(x=0.0,0.5,1.0,1.5,and 2.0)samples ranges from 28.37 to 39.12 nm.The Fourier transform infrared spectroscopy(FTIR)spectra confirm the lattice vibration at the octahedral and tetrahedral sites.The strong emission peaks of 3.40 eV are seen at 364 nm.It is found that photoluminescence intensity reduces with Ce-Tb substitution,which is associated with a reduction in electron-hole recombination.In the temperature range of room temperature(23℃)to 200℃,the dielectric constant,dielectric loss,and AC conductivity were computed over a broad frequency range of 10^(2)-10^(5) Hz.Maxwell-Wagner's two-laye r model explains the frequency dependent dielectric behaviour of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples.The dielectric constant increases for the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples as the Ce-Tb concentration increases up to x=1.0,and with further increasing the Ce^(3+)and Tb^(3+)ions up to x=2.0 the dielectric constant decreases.All of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples exhibit non-Debye type relaxation behaviour,according to the impedance measurement.The substitution of Ce^(3+)and Tb^(3+)ions reduces the grain boundary density,resulting in the low values of the impedance at the grain boundaries.It is found that the multiple hopping conduction process is the main mechanism in the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)compounds.展开更多
The ionization chamber produces significant space-charge and ion recombination effects at ultra-high dose rates,posing achallenge for dose monitoring.In addition,there is no generally accepted ion correction model for...The ionization chamber produces significant space-charge and ion recombination effects at ultra-high dose rates,posing achallenge for dose monitoring.In addition,there is no generally accepted ion correction model for dosimetry in FLASHradiotherapy,making it crucial to monitor the dose at ultra-high dose rates accurately and in real time.In this study,the airpressure of the ionization chamber was reduced to perform real-time beam monitoring,and a Faraday cup was used for calibrationfor active dosimetry.To study the saturation effect of the ionization chamber,the drift,attachment,recombination,anddiffusion processes of the electron-ion pairs were modeled using finite-element analysis based on physical phenomenologicalprinciples,and the correction factor was calculated.The experimental results showed that the FLASH ionization chambermeasures good dose linearity at a dose rate of approximately 0.2 Gy/s.When the air pressure of the chamber was adjustedto 10 mbar,the response of the FLASH ionization chamber was linear at a dose rate of approximately 50 Gy/s,with theresiduals within 2%.Furthermore,by using physical phenomenology to resolve the process of electron-ion pair motion inthe sensitive volume of the ionization chamber,the analytical model better describes the saturation effect of carbon ions atultra-high dose rates.The maximum deviation in the calculated correction factor is less than 10%.We studied the saturationeffect in dose measurement,achieving accurate and fast dose and profile position measurement across different dose ratesin a wide range based on the Heavy Ion Research Facility in Lanzhou.展开更多
Tuberculosis,an infectious disease,causes considerable morbidity and mortality.Within the host immune system,transition metals play vital roles in combating Mycobacterium tuberculosis(MTB),acting as catalytic cofactor...Tuberculosis,an infectious disease,causes considerable morbidity and mortality.Within the host immune system,transition metals play vital roles in combating Mycobacterium tuberculosis(MTB),acting as catalytic cofactors,mediating electron transport,and catalyzing antimicrobial radical formation.Both the host and MTB have developed mechanisms to maintain metal homeostasis.Flavonoids,important herbal materials with potent iron-chelating ability,have gained attention for their antitubercular and anti-inflammatory effects,making them a promising treatment option.This review explores how trace metals restrict MTB and the dynamic balance between pathogen and host,revealing innovative perspectives for therapeutic interventions.展开更多
Grouting represents a reliable method for strengthening fractured rock masses and preventing seawater infiltration in subsea tunnel engineering. However, grouting composites are continuously subjected to harsh marine ...Grouting represents a reliable method for strengthening fractured rock masses and preventing seawater infiltration in subsea tunnel engineering. However, grouting composites are continuously subjected to harsh marine environments,experiencing both chemical and physical effects from high-concentration erosive seawater ions, elevated water pressure, and complex flow fields. This multi-factor erosion deterioration diminishes the waterproofing capabilities of grouting composites and threatens the service life of subsea tunnel linings. To investigate the erosion deteriortion mechanism induced by sulfate, erosion weakening experiments were conducted using a seawater flow simulation device. The research examined the compressive strength and permeability coefficient of grouting composites under different erosion durations, water-cement ratios, and grouting pressures. In the later stages of the experiment, the strength of grouting composites in the static water erosion control group(SEG) and dynamic water erosion group(DEG) decreased by 31.2% and 18.8%, respectively, compared to the freshwater control group(FG). Futhermore, the permeability coefficient exhibited significant increases. Subsequent microscopic analyses of the eroded grouting composites were performed. This research elucidated the erosion-weakening mechanism of grouting composites subjected to sulfate-induced degradation in complex marine environments. The study emphasizes the critical role of erosion resistance and durability in design and implementation. From practical perspective, this work establishes a foundation for developing enhanced strategies to improve the long-term performance and integrity of grouting composites in subsea tunnel applications.展开更多
Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;...Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;AEU for Army Engineering University of PLA),was synthesized,which shows good water and chemical stabilities.Significantly,due to channel constriction accompanied by the polar window caused by introducing nitrate ions,AEU-1 exhibits high C_(2)H_(6)/C_(2)H_(4)adsorption selectivity comparable to many famous C_(2)H_(6)-selective MOFs,making it a promising candidate for the purification of methanol-to-olefin(MTO)products.Furthermore,theoretical investigations reveal that the introduced nitrate ions in AEU-1 as the main adsorption sites could provide strong interactions between the framework and C2H6/C3H6 in the full-contacting mode,leading to an increase in the adsorption enthalpies(Qst)of C_(2)H_(6)and C_(3)H_(6),and thus further improving the C_(2)H_(6)/C_(2)H_(4)and C_(3)H_(6)/C_(2)H_(4)adsorption selectivity.Our work could open up a new avenue for constructing MOFs with inorganic polar moieties as adsorption sites for one-step C_(2)H_(4)purification and C3H6 recovery from MTO mixtures with high selectivity.展开更多
State-selective single-and double-electron capture processes in collisions of S^(5+)ions with helium at energies ranging from 50.8 keV to 100 keV were investigated using cold target recoil ion momentum spectroscopy(CO...State-selective single-and double-electron capture processes in collisions of S^(5+)ions with helium at energies ranging from 50.8 keV to 100 keV were investigated using cold target recoil ion momentum spectroscopy(COLTRIMS).Q-value spectra and projectile scattering angle distributions were obtained.For single-electron capture,single electron capture into n=3 states of the projectile ion is dominant.As the projectile energy increases,the contribution of single electron capture into n=4 states is observed.Experimental relative cross-sections for single-electron capture into different projectile final states were compared with theoretical predictions based on the molecular orbital close-coupling(MOCC)method.In double-electron capture,two-electron populating into the 3s^(2)3p and 3s3p^(2)states of projectile dominates.The reaction window calculated from the classical molecular Coulombic barrier model can qualitatively explain the experimental results.The scattering angle distribution of the multi-peak structure of the double-electron capture process is observed.The database is openly available in Science Data Bank at https://doi.org/10.57760/sciencedb.j00113.00233.展开更多
As an important sustainable energy source,Li-ion batteries have been widely used in mobile phones,electric vehicles,large-scale energy storage and aerospace.However,due to the inevitable safety risks of traditional li...As an important sustainable energy source,Li-ion batteries have been widely used in mobile phones,electric vehicles,large-scale energy storage and aerospace.However,due to the inevitable safety risks of traditional liquid Li-ion batteries,the use of all-solid-state batteries to replace organic liquid electrolytes has become one of the most effective ways to solve safety problem.Solid-state electrolyte(SSE)is the core part of allsolid-state Li-ion battery,and ideal SSE has the characteristics of high ionic conductivity,wide enough electrochemical stability window,suitable mechanical strength and excellent chemical stability,the first among which is particularly an essential prerequisite.While,so far only a few SSEs exhibit the Li ionic conductivities higher than 10^(-4) S/cm at room temperature.展开更多
We study the fragmentation of NO^(q+)(q=2,3)molecular ions produced by collisions between 96 keV O^(6+)ions and neutral nitric oxide(NO)molecules,using the cold target recoil ion momentum spectrometer(COLTRIMS).The ki...We study the fragmentation of NO^(q+)(q=2,3)molecular ions produced by collisions between 96 keV O^(6+)ions and neutral nitric oxide(NO)molecules,using the cold target recoil ion momentum spectrometer(COLTRIMS).The kinetic energy release(KER)for various dissociation channels is obtained.For the channel NO^(2+)→N^(+)+O^(+),double-electron capture followed by autoionization of the projectile ions is the dominant process,which can be explained by the recapture of loosely bound electrons into highly excited states of the target.For NO3+trication,two dissociation channels,i.e.,(a)N^(+)+O^(2+)and(b)N^(2+)+O^(+),are observed,where channel(b)is the dominant channel.Moreover,for dissociation channels originating from the same parent molecular ion,the dissociation channel with a higher charge for the oxygen ion fragment exhibits a higher most probable KER,which is consistent with studies of CO fragmentation by Rajput et al.Additionally,it is observed that as capture stability increases,the average KER shifts to higher values.展开更多
基金supported by the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0301200,2021ZD0303200,and 2021ZD0301500)the Alliance of International Science Organizations(ANSO)。
文摘Recently,large-scale trapped ion systems have been realized in experiments for quantum simulation and quantum computation.They are the simplest systems for dynamical stability and parametric resonance.In this model,the Mathieu equation plays the most fundamental role for us to understand the stability and instability of a single ion.In this work,we investigate the dynamics of trapped ions with the Coulomb interaction based on the Hamiltonian equation.We show that the many-body interaction will not influence the phase diagram for instability.Then,the dynamics of this model in the large damping limit will also be analytically calculated using few trapped ions.Furthermore,we find that in the presence of modulation,synchronization dynamics can be observed,showing an exchange of velocities between distant ions on the left side and on the right side of the trap.These dynamics resemble that of the exchange of velocities in Newton's cradle for the collision of balls at the same time.These dynamics are independent of their initial conditions and the number of ions.As a unique feature of the interacting Mathieu equation,we hope this behavior,which leads to a quasi-periodic solution,can be measured in current experimental systems.Finally,we have also discussed the effect of anharmonic trapping potential,showing the desynchronization during the collision process.It is hoped that the dynamics in this many-body Mathieu equation with damping may find applications in quantum simulations.This model may also find interesting applications in dynamics systems as a pure mathematical problem,which may be beyond the results in the Floquet theorem.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant Nos.2020B0301030008 and 2023A1515010416)the National Natural Science Foundation of China(Grant Nos.12375073,12275091,12147128,and 12035007).
文摘We study the production of the X(6900)in the ultra-peripheral heavy ion collisions at the LHC energy region.The potential quantum numbers of X(6900)could be 0^(±+)and 2^(±+).We find that the transverse momentum and the polar angle distributions of X(6900)can be used to distinguish these four potential quantum numbers.These characteristic distributions originate from linearly polarized photons emitted by relativistic nuclei and can be measured by further LHC experiments.
文摘Based on the data of meteorological elements and concentration of negative ions in the county town station,Luguhe station and Yunjishan station during 2020-2024,the temporal and spatial variations in the concentration of negative ions and their influencing factors in Xinfeng County were analyzed.The results show that the concentration of negative ions was the highest in summer,followed by spring;it was lower in autumn and the lowest in winter.In terms of diurnal variations,it was higher in the early morning and night,and lower in the noon and afternoon,which was closely related to the diurnal variations of human activities and meteorological conditions.The factors that affect the concentration of negative ions in the air are more complex.Besides meteorological factors,vegetation,altitude,human activities and other factors should be considered.
基金financial support from the National Natural Science Foundation of China(Nos.U2067201,52204300)the National 111 Project,China(No.B14034)the Fundamental Research Funds for the Central Universities of Central South University,China(No.2021zzts0297).
文摘The combined reagents of sodium N-oleoylsarcosinate(SNOS)with metal ions(Ca(Ⅱ),Mg(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ))was employed to facilitate the separation of lepidolite from feldspar.The synergistic interaction mechanism of this combined reagent was systematically investigated via contact angle measurements,AFM,FTIR,species distribution calculations,and DFT calculations.The results suggested that Ca(Ⅱ)exhibited the best selectivity for activating lepidolite flotation.SNOS was chemically adsorbed on the Ca(Ⅱ)-activated lepidolite surface with an adsorption energy of−1248.91 kJ/mol while a lower adsorption energy of−598.84 kJ/mol of SNOS on Ca(Ⅱ)-activated feldspar was calculated.Therefore,this combination of SNOS and Ca(Ⅱ)is a promising reagent scheme for the efficient recovery of lithium from aluminosilicate ore.
基金supported by the National Natural Science Foundation of China(Nos.12035019,62234013,12205350,12075290,12175287)the China National Postdoctoral Program for Innovative Talents(BX20200340)+1 种基金the fund of Innovation Center of Radiation Application(No.KFZC2022020601)the Chinese Academy of Sciences(CAS)“Light of West China"Program hosted by Jian Zeng.
文摘Gallium nitride(GaN)-based devices have significant potential for space applications.However,the mechanisms of radiation damage to the device,particularly from strong ionizing radiation,remains unknown.This study investigates the effects of radiation on p-gate AlGaN/GaN high-electron-mobility transistors(HEMTs).Under a high voltage,the HEMT leakage current increased sharply and was accompanied by a rapid increase in power density that caused"thermal burnout"of the devices.In addition,a burnout signature appeared on the surface of the burned devices,proving that a single-event burnout effect occurred.Additionally,degradation,including an increase in the on-resistance and a decrease in the breakdown voltage,was observed in devices irradiated with high-energy heavy ions and without bias.The latent tracks induced by heavy ions penetrated the heterojunction interface and extended into the GaN layer.Moreover,a new type of N_(2)bubble defect was discovered inside the tracks using Fresnel analysis.The accumulation of N_(2)bubbles in the heterojunction and buffer layers is more likely to cause leakage and failure.This study indicates that electrical stress accelerates the failure rate and that improving heat dissipation is an effective reinforcement method for GaN-based devices.
基金Supported by the National Natural Science Foundation of China(42474239,41204128)China National Space Administration(Pre-research project on Civil Aerospace Technologies No.D010301)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA17010303)。
文摘One of the detection objectives of the Chinese Asteroid Exploration mission is to investigate the space environment near the Main-belt Comet(MBC,Active Asteroid)311P/PANSTARRS.This paper outlines the scientific objectives,measurement targets,and measurement requirements for the proposed Gas and Ion Analyzer(GIA).The GIA is designed for in-situ mass spectrometry of neutral gases and low-energy ions,such as hydrogen,carbon,and oxygen,in the vicinity of 311P.Ion sampling techniques are essential for the GIA's Time-of-Flight(TOF)mass analysis capabilities.In this paper,we present an enhanced ion sampling technique through the development of an ion attraction model and an ion source model.The ion attraction model demonstrates that adjusting attraction grid voltage can enhance the detection efficiency of low-energy ions and mitigate the repulsive force of ions during sampling,which is influenced by the satellite's surface positive charging.The ion source model simulates the processes of gas ionization and ion multiplication.Simulation results indicate that the GIA can achieve a lower pressure limit below 10-13Pa and possess a dynamic range exceeding 10~9.These performances ensure the generation of ions with stable and consistent current,which is crucial for high-resolution and broad dynamic range mass spectrometer analysis.Preliminary testing experiments have verified GIA's capability to detect gas compositions such as H2O and N2.In-situ measurements near 311P using GIA are expected to significantly contribute to our understanding of asteroid activity mechanisms,the evolution of the atmospheric and ionized environments of main-belt comets,the interactions with solar wind,and the origin of Earth's water.
基金Project(50621063) supported by the National Natural Science Foundation of ChinaProject(2010CB630903) supported by the National Basic Research Program of China
文摘The extracellular polymeric substances（EPS） of Acidithiobacillus ferrooxidans ATCC 23270,and iron and copper enclosed in EPS were extracted by ultrasonication and centrifugation methods to determine the interaction mechanism of Cu2＋,Fe3＋ and EPS during bioleaching chalcopyrite.Generally,Cu2＋ ions can stimulate bacteria to produce more EPS than Fe3＋ ions.The mass ratio of Fe3＋/Cu2＋ enclosed in EPS decreased gradually from about 4：1 to about 2：1 when the concentration of Cu2＋ ions increased from 0.01 to 0.04 mol/L.The amount of iron and copper bound together by EPS in ferrous-free 9K medium containing 1% chalcopyrite was about 2 times of that in 9K medium containing 0.04 mol/L Cu2＋ ions.It was inferred that the EPS with jarosites on the surface of chalcopyrite gradually acted as a weak diffusion barrier for Cu2＋,Fe3＋ ions transference during bioleaching chalcopyrite.
基金Project(51174229) supported by the National Natural Science Foundation of China
文摘The effects of copper ions and calcium ions on the depression of chlorite using CMC（carboxymethyl cellulose） as a depressant were studied through flotation tests,adsorption measurements,ζ potential tests and co-precipitation experiments.The results show that the electrostatic repulsion between the CMC molecules and the chlorite surfaces hinders the approach of the CMC to the chlorite while the presence of copper ions and calcium ions enhances the adsorption density of CMC.The action mechanisms of these two types of ions are different.Calcium ions can not adsorb onto the mineral surfaces,but they can interact with the CMC molecules,thus reducing the charge of the CMC and enhancing adsorption density.Copper ions can adsorb onto the mineral surfaces,which facilitates the CMC adsorption through acid/base interaction.The enhanced adsorption density is also attributed to the decreased electrostatic repulsion between the CMC and mineral surfaces as copper ions reduce the surface charge of both the mineral surfaces and the CMC molecules.
基金supported by the National Natural Science Foundation of China(Nos.61705027,62375031 and 52075131)the Chongqing Science and Technology Commission Basic Research Project(No.CSTC-2020jcyj-msxm0603)the Chongqing Municipal Education Commission Science and Technology Research Program(No.KJQN202000609)。
文摘To address the temperature cross-talk issue in detecting heavy metal ions in natural waters, a highly-integrated and fully fiber-optic metal ion sensing system capable of temperature-concentration decoupling measurement has been designed. This system integrates a fluidic detection structure assisted by side-polished fibers(SPFs) with a Sagnac interferometer.
基金supported by National Natural Science Foundation of China(Nos.22176012,51878023)BUCEA Post Graduate Innovation Project(No.PG2023057)BUCEA Doctor Graduate Scientific Research Ability Improvement Project(No.DG2024022)。
文摘The nano-MOF-303 synthesized by microwave method exhibited efficient adsorption capacity(232 mg/g)toward Ag^(+),in which the adsorption behaviors were fitted by the pseudo-second-order kinetic and the Freundlich isotherm model.The outstanding Ag^(+)sorption ability of nano-MOF-303 could be contributed to electrostatic interactions,weak coordination interaction of Ag-N,and Ag Cl precipitates originating from the stored Cl^(-)in nano-MOF-303.Besides the adsorbent regeneration,the formed Ag/Ag Cl onto nano-MOF-303 could produce Ag/Ag Cl/MOF-303 as a photocatalyst for sulfamethoxazole degradation under visible light.In this work,both the adsorption and photocatalysis mechanisms were clarified,which might provide insight to develop more effective adsorbents for mining the critical resource from the wastewater.
基金supported by the Liaoning Provincial Science and Technology Program-Excellent Youth Fund Program(2023JH3/10200002)National Key Research and Development Program of China(2022YFC2406000)+1 种基金National Natural Science Foundation of China(52301308)IMR Innovation fund(2023-PY15).
文摘Ti6Al4V alloy has been widely used in dental applications,such as orthodontic mini-implants.However,it has been reported that fluoride ions could obviously accelerate the corrosion of implant materials and affect their performance.This work aimed to improve the F^(−)erosion resistance of Ti6Al4V alloy through the strategy of both Cu addition and grain refinement.As contrasted with Ti6Al4V alloy,both the coarse-and ultrafine-grained Ti6Al4V-5Cu alloys effectively mitigated the acceleration of the fluoride ions to the anode process,because Cu substituents blocked the continuous damage of F·_(O) doped in the passive film.Furthermore,grain refinement enhanced the protective ability of the passive film,more oxides and less adsorption amount of fluorides presented in the passive film of ultrafine-grained Ti6Al4V-5Cu alloy than those of coarse-grained Ti6Al4V-5Cu alloy.Under the combination of Cu alloying and grain refinement,the ultrafine-grained Ti6Al4V-5Cu alloy is greatly appropriate for the fabrication of orthodontic devices.
基金financial support from the National Key Research and Development Project of China(No.2022YFE0113800)the Natural Science Foundation of Zhejiang Province(No.LY23E020010)+1 种基金the National Natural Science Foundation of China(Nos.U21A20174 and 52225208)the funding from China Postdoctoral Science Foundation(No.2023M743098)。
文摘The in-depth study of the transport properties of the solid electrolyte interface(SEI)is crucial for the development of ultra-high-rate,and long lifespan sodium-ion batteries(SIBs).However,there remains a lack of theoretical investigation into the transport mechanisms of the main inorganic components of the SEI,namely Na F,Na_(2)O,and Na_(2)CO_(3).To address this research gap,we performed classical molecular dynamics simulations in this work to study the diffusion mechanisms of sodium ions in these inorganic components of the SEI,with special emphasis on the impact of the amorphous SEI environment on the diffusion behavior of sodium ions.The results have shown that amorphous SEI components significantly enhance the diffusion rate of sodium ions at room temperature compared to crystalline components.Within these amorphous SEI components,we reveal that the diffusion coefficients of sodium ions in amorphous Na_(2)O and Na_(2)CO_(3)are more than an order of magnitude higher than that of Na F,suggesting that amorphous Na_(2)O and Na_(2)CO_(3)are more effective in facilitating the Na ion diffusion.Analysis of the local atomic structure indicates that the amorphous local structures are dominant in Na_(2)O and Na_(2)CO_(3)at room temperature,maintaining a disordered amorphous phase.In contrast,amorphous Na F undergoes a spontaneously transformation into an ordered structure,exhibiting crystalline characteristics that restrict the diffusion of sodium ions.In summary,our work provides atomic insights into the impact of local amorphous environments on Na ion diffusion in SEI and suggests that amorphous SEI components play a critical role in improving battery performance.
文摘Here,the effect of cerium and terbium ions substitution on structural,optical,dielectric,and electrical properties of Ca_(0.95)Y_(0.05)Fe_(12)O_(19)M-type hexaferrite prepared by solvent free method i.e.,auto co mbustion method was reported.The X-ray diffraction technique was used for the structural examination.The hexagonal structure of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples is confirmed by X-ray diffraction(XRD)pattern analysis.The crystallite size of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)(x=0.0,0.5,1.0,1.5,and 2.0)samples ranges from 28.37 to 39.12 nm.The Fourier transform infrared spectroscopy(FTIR)spectra confirm the lattice vibration at the octahedral and tetrahedral sites.The strong emission peaks of 3.40 eV are seen at 364 nm.It is found that photoluminescence intensity reduces with Ce-Tb substitution,which is associated with a reduction in electron-hole recombination.In the temperature range of room temperature(23℃)to 200℃,the dielectric constant,dielectric loss,and AC conductivity were computed over a broad frequency range of 10^(2)-10^(5) Hz.Maxwell-Wagner's two-laye r model explains the frequency dependent dielectric behaviour of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples.The dielectric constant increases for the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples as the Ce-Tb concentration increases up to x=1.0,and with further increasing the Ce^(3+)and Tb^(3+)ions up to x=2.0 the dielectric constant decreases.All of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples exhibit non-Debye type relaxation behaviour,according to the impedance measurement.The substitution of Ce^(3+)and Tb^(3+)ions reduces the grain boundary density,resulting in the low values of the impedance at the grain boundaries.It is found that the multiple hopping conduction process is the main mechanism in the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)compounds.
文摘The ionization chamber produces significant space-charge and ion recombination effects at ultra-high dose rates,posing achallenge for dose monitoring.In addition,there is no generally accepted ion correction model for dosimetry in FLASHradiotherapy,making it crucial to monitor the dose at ultra-high dose rates accurately and in real time.In this study,the airpressure of the ionization chamber was reduced to perform real-time beam monitoring,and a Faraday cup was used for calibrationfor active dosimetry.To study the saturation effect of the ionization chamber,the drift,attachment,recombination,anddiffusion processes of the electron-ion pairs were modeled using finite-element analysis based on physical phenomenologicalprinciples,and the correction factor was calculated.The experimental results showed that the FLASH ionization chambermeasures good dose linearity at a dose rate of approximately 0.2 Gy/s.When the air pressure of the chamber was adjustedto 10 mbar,the response of the FLASH ionization chamber was linear at a dose rate of approximately 50 Gy/s,with theresiduals within 2%.Furthermore,by using physical phenomenology to resolve the process of electron-ion pair motion inthe sensitive volume of the ionization chamber,the analytical model better describes the saturation effect of carbon ions atultra-high dose rates.The maximum deviation in the calculated correction factor is less than 10%.We studied the saturationeffect in dose measurement,achieving accurate and fast dose and profile position measurement across different dose ratesin a wide range based on the Heavy Ion Research Facility in Lanzhou.
文摘Tuberculosis,an infectious disease,causes considerable morbidity and mortality.Within the host immune system,transition metals play vital roles in combating Mycobacterium tuberculosis(MTB),acting as catalytic cofactors,mediating electron transport,and catalyzing antimicrobial radical formation.Both the host and MTB have developed mechanisms to maintain metal homeostasis.Flavonoids,important herbal materials with potent iron-chelating ability,have gained attention for their antitubercular and anti-inflammatory effects,making them a promising treatment option.This review explores how trace metals restrict MTB and the dynamic balance between pathogen and host,revealing innovative perspectives for therapeutic interventions.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 42477194 and 52279115)Fundamental Research Funds for the Central Universities (Grant No. 202441008)。
文摘Grouting represents a reliable method for strengthening fractured rock masses and preventing seawater infiltration in subsea tunnel engineering. However, grouting composites are continuously subjected to harsh marine environments,experiencing both chemical and physical effects from high-concentration erosive seawater ions, elevated water pressure, and complex flow fields. This multi-factor erosion deterioration diminishes the waterproofing capabilities of grouting composites and threatens the service life of subsea tunnel linings. To investigate the erosion deteriortion mechanism induced by sulfate, erosion weakening experiments were conducted using a seawater flow simulation device. The research examined the compressive strength and permeability coefficient of grouting composites under different erosion durations, water-cement ratios, and grouting pressures. In the later stages of the experiment, the strength of grouting composites in the static water erosion control group(SEG) and dynamic water erosion group(DEG) decreased by 31.2% and 18.8%, respectively, compared to the freshwater control group(FG). Futhermore, the permeability coefficient exhibited significant increases. Subsequent microscopic analyses of the eroded grouting composites were performed. This research elucidated the erosion-weakening mechanism of grouting composites subjected to sulfate-induced degradation in complex marine environments. The study emphasizes the critical role of erosion resistance and durability in design and implementation. From practical perspective, this work establishes a foundation for developing enhanced strategies to improve the long-term performance and integrity of grouting composites in subsea tunnel applications.
基金supported by the Youth Autonomous Innovation Funding from Army Engineering University of PLA(KYJBJKQTZQ23005)the Basic Discipline Incubation Funding from Army Engineering University of PLA(KYJBJKQTZK23011).
文摘Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;AEU for Army Engineering University of PLA),was synthesized,which shows good water and chemical stabilities.Significantly,due to channel constriction accompanied by the polar window caused by introducing nitrate ions,AEU-1 exhibits high C_(2)H_(6)/C_(2)H_(4)adsorption selectivity comparable to many famous C_(2)H_(6)-selective MOFs,making it a promising candidate for the purification of methanol-to-olefin(MTO)products.Furthermore,theoretical investigations reveal that the introduced nitrate ions in AEU-1 as the main adsorption sites could provide strong interactions between the framework and C2H6/C3H6 in the full-contacting mode,leading to an increase in the adsorption enthalpies(Qst)of C_(2)H_(6)and C_(3)H_(6),and thus further improving the C_(2)H_(6)/C_(2)H_(4)and C_(3)H_(6)/C_(2)H_(4)adsorption selectivity.Our work could open up a new avenue for constructing MOFs with inorganic polar moieties as adsorption sites for one-step C_(2)H_(4)purification and C3H6 recovery from MTO mixtures with high selectivity.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFA1602500)the National Natural Science Foundation of China(Grant No.11974358)。
文摘State-selective single-and double-electron capture processes in collisions of S^(5+)ions with helium at energies ranging from 50.8 keV to 100 keV were investigated using cold target recoil ion momentum spectroscopy(COLTRIMS).Q-value spectra and projectile scattering angle distributions were obtained.For single-electron capture,single electron capture into n=3 states of the projectile ion is dominant.As the projectile energy increases,the contribution of single electron capture into n=4 states is observed.Experimental relative cross-sections for single-electron capture into different projectile final states were compared with theoretical predictions based on the molecular orbital close-coupling(MOCC)method.In double-electron capture,two-electron populating into the 3s^(2)3p and 3s3p^(2)states of projectile dominates.The reaction window calculated from the classical molecular Coulombic barrier model can qualitatively explain the experimental results.The scattering angle distribution of the multi-peak structure of the double-electron capture process is observed.The database is openly available in Science Data Bank at https://doi.org/10.57760/sciencedb.j00113.00233.
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2020MB049)the Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(No.AMGM2023A07)。
文摘As an important sustainable energy source,Li-ion batteries have been widely used in mobile phones,electric vehicles,large-scale energy storage and aerospace.However,due to the inevitable safety risks of traditional liquid Li-ion batteries,the use of all-solid-state batteries to replace organic liquid electrolytes has become one of the most effective ways to solve safety problem.Solid-state electrolyte(SSE)is the core part of allsolid-state Li-ion battery,and ideal SSE has the characteristics of high ionic conductivity,wide enough electrochemical stability window,suitable mechanical strength and excellent chemical stability,the first among which is particularly an essential prerequisite.While,so far only a few SSEs exhibit the Li ionic conductivities higher than 10^(-4) S/cm at room temperature.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1602500)the National Natural Science Foundation of China(Grant Nos.11934004,12064040,and 11974358)Strategic Key Research Program of the Chinese Academy of Sciences(Grant No.XDB34020000).
文摘We study the fragmentation of NO^(q+)(q=2,3)molecular ions produced by collisions between 96 keV O^(6+)ions and neutral nitric oxide(NO)molecules,using the cold target recoil ion momentum spectrometer(COLTRIMS).The kinetic energy release(KER)for various dissociation channels is obtained.For the channel NO^(2+)→N^(+)+O^(+),double-electron capture followed by autoionization of the projectile ions is the dominant process,which can be explained by the recapture of loosely bound electrons into highly excited states of the target.For NO3+trication,two dissociation channels,i.e.,(a)N^(+)+O^(2+)and(b)N^(2+)+O^(+),are observed,where channel(b)is the dominant channel.Moreover,for dissociation channels originating from the same parent molecular ion,the dissociation channel with a higher charge for the oxygen ion fragment exhibits a higher most probable KER,which is consistent with studies of CO fragmentation by Rajput et al.Additionally,it is observed that as capture stability increases,the average KER shifts to higher values.
