In this paper,the local fractional natural decomposition method(LFNDM)is used for solving a local fractional Poisson equation.The local fractional Poisson equation plays a significant role in the study of a potential ...In this paper,the local fractional natural decomposition method(LFNDM)is used for solving a local fractional Poisson equation.The local fractional Poisson equation plays a significant role in the study of a potential field due to a fixed electric charge or mass density distribution.Numerical examples with computer simulations are presented in this paper.The obtained results show that LFNDM is effective and convenient for application.展开更多
Any polyhedron accommodates a type of potential theoretic skeleton called a mother body. The study of such mother bodies was originally from Mathematical Physics, initiated by Zidarov [1] and developed by Bjö...Any polyhedron accommodates a type of potential theoretic skeleton called a mother body. The study of such mother bodies was originally from Mathematical Physics, initiated by Zidarov [1] and developed by Björn Gustafson and Makoto Sakai [2]. In this paper, we attempt to apply the brilliant idea of mother body to Electrostatics to compute the potentials of electric fields.展开更多
The national standardization technical committee on electrostatics,SAC/TC 597,was set up by Standardization Administration of China(SAC)recently.The Ministry of Industry and Information Technology(MIIT)is in charge of...The national standardization technical committee on electrostatics,SAC/TC 597,was set up by Standardization Administration of China(SAC)recently.The Ministry of Industry and Information Technology(MIIT)is in charge of its routine management and operational guidance,and China Electronics Standardization Institute(CESl)undertakes the secretariat.展开更多
Non-hermiticity presents a vast newly opened territory that harbors new physics and applications such as lasing and sensing.However,only non-Hermitian systems with real eigenenergies are stable,and great efforts have ...Non-hermiticity presents a vast newly opened territory that harbors new physics and applications such as lasing and sensing.However,only non-Hermitian systems with real eigenenergies are stable,and great efforts have been devoted in designing them through enforcing parity-time(PT)symmetry.In this work,we exploit a lesser-known dynamical mechanism for enforcing real-spectra,and develop a comprehensive and versatile approach for designing new classes of parent Hamiltonians with real spectra.Our design approach is based on a new electrostatics analogy for modifed non-Hermitian bulk-boundary correspondence,where electrostatic charge corresponds to density of states and electric felds correspond to complex spectral fow.As such,Hamiltonians of any desired spectra and state localization profle can be reverse-engineered,particularly those without any guiding symmetry principles.By recasting the diagonalization of non-Hermitian Hamiltonians as a Poisson boundary value problem,our electrostatics analogy also transcends the gain/loss-induced compounding of foating-point errors in traditional numerical methods,thereby allowing access to far larger system sizes.展开更多
We present a novel method for designing transformation optical devices based on electrostatics.An arbi-trary transformation of electrostatic field can lead to a new refractive index distribution,where wave-fronts and ...We present a novel method for designing transformation optical devices based on electrostatics.An arbi-trary transformation of electrostatic field can lead to a new refractive index distribution,where wave-fronts and energy flux lines correspond to equipotential surfaces and electrostatic flux lines,respectively.Owing to scalar wave propagating exactly following an eikonal equation,wave optics and geometric optics share the same solutions in the devices.The method is utilized to design multipole lenses derived from multipoles in electrostatics.The source and drain in optics are considered as corre-sponding to positive charge and negative charge in the static field.By defining winding numbers in vir-tual and physical spaces,we explain the reason for some multipole lenses with illusion effects.Besides,we introduce an equipotential absorber to replace the drain to correspond to a negative charge with a grounded conductor.Therefore,it is a very general platform to design intriguing devices based on the combination of electrostatics and transformation optics.展开更多
A new VMD plugin that interfaces with DelPhi to provide ensemble-averaged electrostatic calculations using the Poisson-Boltzmann equation is presented.The general theory and context of this approach are discussed,and ...A new VMD plugin that interfaces with DelPhi to provide ensemble-averaged electrostatic calculations using the Poisson-Boltzmann equation is presented.The general theory and context of this approach are discussed,and examples of the plugin interface and calculations are presented.This new tool is applied to systems of current biological interest,obtaining the ensemble-averaged electrostatic properties of the two major influenza virus glycoproteins,hemagglutinin and neuraminidase,from explicitly solvated all-atom molecular dynamics trajectories.The differences between the ensemble-averaged electrostatics and those obtained from a single structure are examined in detail for these examples,revealing how the plugin can be a powerful tool in facilitating the modeling of electrostatic interactions in biological systems.展开更多
Wepresent a new approach to constructmachine-learned interatomic potentials including long-range electrostatic interactions based on a charge equilibration scheme.This new approach can accurately describe the potentia...Wepresent a new approach to constructmachine-learned interatomic potentials including long-range electrostatic interactions based on a charge equilibration scheme.This new approach can accurately describe the potential energy surface of systems with ionic and covalent interactions as well as systems with multiple charge states.Moreover,it can either be regressed against known atomic charge decompositions or trained without charge targets,without compromising the accuracy of energy and forces.We benchmark our approach against other state-of-the-art models and prove it to have equivalent performances on a set of simple reference systems while being less computationally expensive.Finally,we demonstrate the accuracy of our approach on complex systems:solid and liquid state sodium chloride.We attain accuracy in energy and forces better than the model based on local descriptors and show that our electrostatic approach can capture the density functional theory tail of the potential energy surface of the isolated Na-Cl dimer,which the local descriptor-based model fails to describe.展开更多
A mobile Coulomb gas permeating a fixed background crystalline lattice of charged colloidal crystals is subject to an electrostatic-elastic coupling,which we study on the continuum level by introducing a minimal coupl...A mobile Coulomb gas permeating a fixed background crystalline lattice of charged colloidal crystals is subject to an electrostatic-elastic coupling,which we study on the continuum level by introducing a minimal coupling between electrostatic and displacement fields.We derive linearized,Debye–Hückel-like mean-field equations that can be analytically solved,incorporating the minimal coupling between electrostatic and displacement fields leading to an additional effective attractive interaction between mobile charges that depends in general on the strength of the coupling between the electrostatic and displacement fields.By analyzing the Gaussian fluctuations around the mean-field solution we also identify and quantify the region of its stability in terms of the electrostatic-elastic screening length.This detailed continuum theory incorporating the standard lattice elasticity and electrostatics of mobile charges provides a baseline to investigate the electrostatic-elastic coupling for microscopic models in colloid science and materials science.展开更多
Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent.Multi-component interface engineering is con...Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent.Multi-component interface engineering is considered an effective means to achieve high-efficiency EMW absorption.However,interface modulation engineering has not been fully discussed and has great potential in the field of EMW absorption.In this study,multi-component tin compound fiber composites based on carbon fiber(CF)substrate were prepared by electrospinning,hydrothermal synthesis,and high-temperature thermal reduction.By utilizing the different properties of different substances,rich heterogeneous interfaces are constructed.This effectively promotes charge transfer and enhances interfacial polarization and conduction loss.The prepared SnS/SnS_(2)/SnO_(2)/CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt%in epoxy resin.The minimum reflection loss(RL)is−46.74 dB and the maximum effective absorption bandwidth is 5.28 GHz.Moreover,SnS/SnS_(2)/SnO_(2)/CF epoxy composite coatings exhibited long-term corrosion resistance on Q235 steel surfaces.Therefore,this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments.展开更多
Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundame...Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundamental understanding on how they control the electrochemical performances.Herein,by harnessing the electrostatic adsorption of one-dimensional nanofiller(i.e.,surface-charged halloysite nanotubes,d-HNTs),we successfully fabricate a high-performance polymer nanocomposite electrolyte enabled by strong surface adsorption,referred as adsorption-state polymer electrolyte(ASPE).This ASPE shows fast ion transport(0.71±0.05 mS cm^(-1)at room temperature),high mechanical strength and toughness(10.3±0.05 MPa;15.73 MJ m^(-3)),improved lithium-ion transference number,and long cycle life with lithium metal anode,in comparison with the sample without the d-HNT adsorption effect.To fundamentally understand these high performances,an anion-rich asymmetric solvent structure model is further proposed and evidenced by both experiments and simulation studies.Results show that the electrostatic adsorption among the d-HNT,ionic liquid electrolyte,and polymer chain generates a nano filler-supported fast ion-conduction pathway with asymmetric Li+-coordination microenvironment.Meanwhile,the anion-rich asymmetric solvent structure model of ASPE also generates a fast de-solvation and anion-derived stable solid-electrolyte interphase for lithium metal anode.The high performance and understanding of the mechanism for ASPE provide a promising path to develop advanced polymer electrolytes.展开更多
Cerium oxide(CeO_(2)) has attracted much attention in recent years owing to its reversible switch ability in Ce^(3+)/Ce^(4+)redox to produce improved antioxidation properties for biomedical applications.Here,we report...Cerium oxide(CeO_(2)) has attracted much attention in recent years owing to its reversible switch ability in Ce^(3+)/Ce^(4+)redox to produce improved antioxidation properties for biomedical applications.Here,we report to embed the CeO_(2)nanospheres into the organic polymer network using electrostatic spinning technology to prepare polyvinyl alcohol(PVA)-encapsulated CeO_(2)nanospheres composite nanofibrous membranes(PVA-CeO_(2)) for the first time,which is beneficial to improving the dispersion and biocompatibility of CeO_(2)nanosphere without altering the original antioxidant properties of CeO_(2).Detailed characterization of the as-prepared composite nanofibrous membranes reveals that CeO_(2)was successfully introduced into the PVA fibers with strong interactions,thus enhancing the thermal stability and fracture toughness of the nanoifbers.As a result,PVA-CeO_(2)exhibits superior UV shielding performance,antioxidant performance and bacteriostatic performance.Meaningfully,PVA-CeO_(2)has strong absorbance in both UVA and UVB bands when the CeO_(2)concentration in the nanoifber membrane reaches 1.5 wt%,and shows an excellent scavenging effect on the 2,2-diphenyl-1-picrylhydrazyl(DPPH)radicals with a scavenging rate of 86.52%.Moreover,the Kirby-Bauer(K-B) method of agar diffusion test further confirms that PVA-CeO_(2)has antimicrobial ability against three types of representative strains,including Gram-positive bacteria(Staphylococcus aureus),Gram-negative bacteria(Escherichia coli) and fungi(Candida albicans).Importantly,no obvious cytotoxicity is observed for PVA-CeO_(2)even though the amount of embedded CeO_(2)nanosphere reaches as high as 1.5 wt%.This study reveals new avenues for improving the future smart design of CeO_(2)-based nanoifber membrane composite materials for biological antioxidants.展开更多
To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying ...To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying method.The morphology,structure and thermal decomposition properties of the samples were analyzed using scanning electron microscopy(SEM),X-ray energy spectroscopy(EDS),infrared spectroscopy(FT-IR),and simultaneous thermal analyzer(TG-DSC).Additionally,the combustion process of the samples was tested using a high-speed camera.The results show that the addition of nano-Si contributes to the formation of composite explosives with regular morphology and smaller particle size.The Si/NC/CL-20 composite explosive has better and more uniform sphericity,with an average particle size of 73.4 nm,compared to the NC/CL-20 composite explosive.The Si/NC/CL-20 composite explosive which produced by the electrostatic spraying method,achieves physically uniform distribution of the components including NC,CL-20,Si.The addition of Si promotes the thermal decomposition of CL-20.In comparison to the NC/CL-20 composite explosive,the activation energy of the Si/NC/CL-20 composite explosive decreases by 16.78 kJ/mol,and the self-accelerated decomposition temperature and the critical temperature of thermal explosion decreases by 3.12 K and 2.61 K,respectively.Furthermore,Si/NC/CL-20 composite explosive has shorter ignition delay time and faster combustion rate compared to the NC/CL-20 composite explosive,which shows that Si can improve the combustion performance of CL-20.展开更多
Preferential oxidation of CO(CO-PROX)in H_(2)-rich streams is highly important for purifying the industrial grade H_(2)used in proton-exchange-membrane fuel cells(PEMFC),but it is still limited to a relatively narrow ...Preferential oxidation of CO(CO-PROX)in H_(2)-rich streams is highly important for purifying the industrial grade H_(2)used in proton-exchange-membrane fuel cells(PEMFC),but it is still limited to a relatively narrow operation temperature window.In this study,the trace amounts of Cu are used to modify a Pt/Al_(2)O_(3)catalyst.The introduced Cu_(2+)species are atomically anchored on Pt nanoparticles through strong electrostatic adsorption.展开更多
The liquid Zr_(100-x)V_(x)(x=8.6,16.5,30)alloys were undercooled to the maximum undercooling of 364 K(0.18 T_(L)),405 K(0.21 T_(L)),and 375 K(0.21 T_(L)),respectively,by using electrostatic levitation technique.The Zr...The liquid Zr_(100-x)V_(x)(x=8.6,16.5,30)alloys were undercooled to the maximum undercooling of 364 K(0.18 T_(L)),405 K(0.21 T_(L)),and 375 K(0.21 T_(L)),respectively,by using electrostatic levitation technique.The Zr_(91.4)V_(8.6) and Zr_(83.5)V_(16.5) alloys present only one recalescence during liquid/solid phase transition,while the Zr_(70)V_(30) alloy presents a transformation from two recalescence to one recalescence phenomenon with a critical undercooling of approximately 300 K.According to the LKT/BCT model,the calculated results of the primary β-Zr dendrite growth velocity in undercooled liquid Zr_(91.4)V_(8.6) and Zr_(83.5)V_(16.5) alloys agree well with the experiments.The velocity inflection points at 119 K of Zr_(91.4)V_(8.6) alloy and 201 K of Zr_(83.5)V_(16.5) alloy could be explained by the competition between solutal undercooling control and thermal undercooling control modes.For Zr_(70)V_(30) alloy solidified in the P1 with twice recalescence,a critical second undercooling of 253 K and corresponding undercooling of 65 and 244 K are obtained.When the un-dercooling is in the range of 65-244 K,the second undercooling would be greater than 253 K,and the residual liquid phase would solidify into anomalous eutectic microstructure for Zr_(70)V_(30) alloy.The Vickers hardness of Zr_(100-x)V_(x)(x=8.6,16.5,30)alloys all show a quadratic relationship with undercooling.Under electrostatic levitation condition,the mechanical property of Zr-V alloys could be significantly regulated through solidifying the alloys at different undercoolings.展开更多
To explore the electrostatic discharge behavior of charged powders in industrial silos,discharge experiments are conducted based on a full-size industrial silo discharge platform.Electrostatic discharge mode,frequency...To explore the electrostatic discharge behavior of charged powders in industrial silos,discharge experiments are conducted based on a full-size industrial silo discharge platform.Electrostatic discharge mode,frequency,and energy are investigated for powders of different polarities.Although the powders have low charge-to-mass ratios(+0.087μC/kg for the positively charged powders and−0.26μC/kg for the negatively charged ones),electrostatic discharges occur approximately every 10 s,with the maximum discharge energy being 800 mJ.Powder polarity considerably influences discharge energy.The positive powders exhibit higher discharge energy than the negative ones,although discharge frequency remains similar for both.Effects of powder charge,humidity,and mass flow on discharge frequency and discharge energy are quantitatively analyzed,providing important insights for the improvement of safety in industrial powder handling.展开更多
For nano-collision, regulating the interaction between nanoparticles(NPs) and electrode interfaces is crucial for the precise analysis of individual NPs. However, existing ultramicroelectrodes(UMEs) suffer from narrow...For nano-collision, regulating the interaction between nanoparticles(NPs) and electrode interfaces is crucial for the precise analysis of individual NPs. However, existing ultramicroelectrodes(UMEs) suffer from narrow electrochemical window and poor electrode interface adhesion, severely hindering the application of precise single NP analysis. Here, we propose a simple and effective interface modification strategy. By electrochemically self-assembling poly(diallyldimethylammonium chloride)(PC) on the surface of carbon nanocone electrodes(CNCEs), we successfully prepared PC-modified CNCEs(PC–CNCEs). These electrodes not only possess sufficiently wide electrochemical window but also exhibit strong adhesion to negatively charged Ag NPs on their surfaces. Surface physical analysis and electrochemical molecule detection validated the high-density loading of PC on the modified electrodes. Furthermore, the working principle of PC–CNCEs for single Ag NP collision detection was further verified through the techniques of nanocollision and double-potential steps. Leveraging these significant advantages, PC–CNCEs not only achieved precise measurements of single or mixed-sized Ag NPs but also detected Ag NP solutions at concentrations as low as fmol/L levels. This advancement offers a new strategy for the rapid and precise analysis of NP colloids.展开更多
Lanthanum ferrite is a representative perovskite-structured rare earth-based bimetallic oxide,which has been widely studied in magnetic materials,sensors,catalysts and batteries.Herein,we designed and prepared polyoxo...Lanthanum ferrite is a representative perovskite-structured rare earth-based bimetallic oxide,which has been widely studied in magnetic materials,sensors,catalysts and batteries.Herein,we designed and prepared polyoxometalate electron acceptor decorated LaFeO_(3)gas-sensitive composite materials with one-dimensional nanoribbons morphology by electrospinning.The effects of different mass fraction of Keggin type phosphotungstic acid(PW_(12)) on the gas-sensitive properties of LaFeO_(3)nanoribbons were investigated.The results show that the response value of LaFeO_(3)/PW_(12)sensor to acetone gas first increases and then decreases with the increase of PW_(12)content.The LaFeO_(3)/3%PW_(12)sensor exhibits a maximum response of 3.35-5 ppm acetone at 250℃,a 2.6 times increase in response value and a 90℃reduction in operating temperature compared to pure LaFeO_(3)nanoribbons.The LaFeO_(3)/3%PW_(12)sensor exhibits good linear relation in ppb-level concentrations and the lowest detection concentration is100 ppb.The sensors also show good repeatability in 6 tests and excellent long-term stability in 30 d.The improvement of the gas sensitive properties of the composite can be attributed to the synergistic effect between the two components.As an electron acceptor,PW_(12) promotes carrier migration between PW_(12)and LaFeO_(3),thereby improving the gas sensing performance of LaFeO_(3).This work promotes the practical application of polyoxometalate to promote rare earth-based gas sensitive materials in sensing field.展开更多
The notorious shuttle effect of polyiodides in aqueous Zinc-iodine(Zn-I2)batteries impedes their practical application,which renders it imperative to address this issue.Here,we report natural gelatin as an advanced aq...The notorious shuttle effect of polyiodides in aqueous Zinc-iodine(Zn-I2)batteries impedes their practical application,which renders it imperative to address this issue.Here,we report natural gelatin as an advanced aqueous binder for iodine-loading cathode to enable stable and efficient Zn-I_(2) batteries.The positively charged region in gelatin presents electrostatic attraction to the iodine species,while the electron-rich regions could donate electrons to form physical or even covalent bonds with iodine species,thus inhibiting polyiodides shuttle effect and boosting redox reaction.A high reversible capacity of 138 mAh g^(-1) after 3000 cycles at 2C and an ultra-long cycling stability of 30000 cycles at 25C with 107 mAh g^(-1) capacity was achieved.Gelatin binder also can accommodate high iodine-loading(~10 mg)cathode,punch cells,and severe temperature conditions(-10℃ and 60℃).In-situ UV-vis absorption spectroscopy,in-situ Raman spectra and theoretical calculation revealed the critical role of gelatin binder in suppressing polyiodide shuttling and accelerating reaction kinetics.This work uncovers the potential of natural low-cost binder material in advanced Zn-I_(2) batteries and drives future study of designing functional binders.展开更多
In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion s...In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion source.Through the finite element analysis method,the electrostatic analyses of insulators and grid plates were carried out,the material and structure parameters of insulators were determined.The maximum electric field around each insulator is about 4 kV/mm,and the maximum electric field between grids is about 14 kV/mm,which can meet the 120 keV withstand voltage holding.The insulation system for the positive ion source accelerator with 120 keV is designed,and the connection and basic parameters of insulators and support flanges are analyzed and determined.展开更多
Magnetic metal has broad application prospects in the field of electromagnetic wave(EMW)absorption due to its excellent dielectric and magnetic properties.However,high density and poor chemical stability constrain the...Magnetic metal has broad application prospects in the field of electromagnetic wave(EMW)absorption due to its excellent dielectric and magnetic properties.However,high density and poor chemical stability constrain their development potential.The combination of magnetic metals with other lightweight carbon materials is an effective solution.In this work,magnetic nanoparticle fiber composites were prepared by electrostatic spinning and high-temperature annealing processes.By adjusting the preparation process and annealing temperature,Co/Co7 Fe_(3)/CF-800 fiber composites containing double-shell hollow structured nanocubes were cleverly synthesized.The material is mixed with paraffin wax and has a minimum reflection loss(RL)of-52.14 dB and a maximum effective absorption bandwidth(EAB)of 6.16 GHz at a load of 10 wt%.By analyzing the electromagnetic parameters of the material,it was demonstrated that the material absorbs EMW through the synergistic effect of dielectric and magnetic losses.Electrochemical testing in a simulated seawater environment demonstrated that the material also has a degree of self-anticorrosion capability.This work provides new strategies for designing materials with excellent electromagnetic wave absorption and self-anticorrosion properties.展开更多
文摘In this paper,the local fractional natural decomposition method(LFNDM)is used for solving a local fractional Poisson equation.The local fractional Poisson equation plays a significant role in the study of a potential field due to a fixed electric charge or mass density distribution.Numerical examples with computer simulations are presented in this paper.The obtained results show that LFNDM is effective and convenient for application.
文摘Any polyhedron accommodates a type of potential theoretic skeleton called a mother body. The study of such mother bodies was originally from Mathematical Physics, initiated by Zidarov [1] and developed by Björn Gustafson and Makoto Sakai [2]. In this paper, we attempt to apply the brilliant idea of mother body to Electrostatics to compute the potentials of electric fields.
文摘The national standardization technical committee on electrostatics,SAC/TC 597,was set up by Standardization Administration of China(SAC)recently.The Ministry of Industry and Information Technology(MIIT)is in charge of its routine management and operational guidance,and China Electronics Standardization Institute(CESl)undertakes the secretariat.
基金supported by Singapore’s MOE Tier I grant WBS No.A-800022-00-00。
文摘Non-hermiticity presents a vast newly opened territory that harbors new physics and applications such as lasing and sensing.However,only non-Hermitian systems with real eigenenergies are stable,and great efforts have been devoted in designing them through enforcing parity-time(PT)symmetry.In this work,we exploit a lesser-known dynamical mechanism for enforcing real-spectra,and develop a comprehensive and versatile approach for designing new classes of parent Hamiltonians with real spectra.Our design approach is based on a new electrostatics analogy for modifed non-Hermitian bulk-boundary correspondence,where electrostatic charge corresponds to density of states and electric felds correspond to complex spectral fow.As such,Hamiltonians of any desired spectra and state localization profle can be reverse-engineered,particularly those without any guiding symmetry principles.By recasting the diagonalization of non-Hermitian Hamiltonians as a Poisson boundary value problem,our electrostatics analogy also transcends the gain/loss-induced compounding of foating-point errors in traditional numerical methods,thereby allowing access to far larger system sizes.
基金the National Natural Science Foundation of China(92050102)the National Key Research and Development Program of China(2020YFA0710100)+1 种基金the National Natural Science Foundation of China(11874311)the FundamentalResearch Funds for the Central Universities(20720200074 and20720190049)。
文摘We present a novel method for designing transformation optical devices based on electrostatics.An arbi-trary transformation of electrostatic field can lead to a new refractive index distribution,where wave-fronts and energy flux lines correspond to equipotential surfaces and electrostatic flux lines,respectively.Owing to scalar wave propagating exactly following an eikonal equation,wave optics and geometric optics share the same solutions in the devices.The method is utilized to design multipole lenses derived from multipoles in electrostatics.The source and drain in optics are considered as corre-sponding to positive charge and negative charge in the static field.By defining winding numbers in vir-tual and physical spaces,we explain the reason for some multipole lenses with illusion effects.Besides,we introduce an equipotential absorber to replace the drain to correspond to a negative charge with a grounded conductor.Therefore,it is a very general platform to design intriguing devices based on the combination of electrostatics and transformation optics.
基金funded in part by the National Institutes of Health through the NIH Director’s New Innovator Award Program 1-DP2-OD007237through the NSF TeraGrid Supercomputer resources grant LRAC CHE060073N to R.E.A.supported by a grant from the Institute of General Medical Sciences,National Institutes of Health,award number 1R01GM093937-01.
文摘A new VMD plugin that interfaces with DelPhi to provide ensemble-averaged electrostatic calculations using the Poisson-Boltzmann equation is presented.The general theory and context of this approach are discussed,and examples of the plugin interface and calculations are presented.This new tool is applied to systems of current biological interest,obtaining the ensemble-averaged electrostatic properties of the two major influenza virus glycoproteins,hemagglutinin and neuraminidase,from explicitly solvated all-atom molecular dynamics trajectories.The differences between the ensemble-averaged electrostatics and those obtained from a single structure are examined in detail for these examples,revealing how the plugin can be a powerful tool in facilitating the modeling of electrostatic interactions in biological systems.
基金supported by the European Commission through the MaX Centre of Excellence(grant number 824143)supported by the European Commission through the MAX Centre of Excellence for supercomputing applications(grant numbers 10109337 and 824143)by the Italian MUR,through the Italian National Centre from HPC,Big Data,and Quantum Computing(grant number CN00000013).
文摘Wepresent a new approach to constructmachine-learned interatomic potentials including long-range electrostatic interactions based on a charge equilibration scheme.This new approach can accurately describe the potential energy surface of systems with ionic and covalent interactions as well as systems with multiple charge states.Moreover,it can either be regressed against known atomic charge decompositions or trained without charge targets,without compromising the accuracy of energy and forces.We benchmark our approach against other state-of-the-art models and prove it to have equivalent performances on a set of simple reference systems while being less computationally expensive.Finally,we demonstrate the accuracy of our approach on complex systems:solid and liquid state sodium chloride.We attain accuracy in energy and forces better than the model based on local descriptors and show that our electrostatic approach can capture the density functional theory tail of the potential energy surface of the isolated Na-Cl dimer,which the local descriptor-based model fails to describe.
基金HW is partially supported by the open research fund of Songshan Lake Materials Laboratory No.2023SLABFN20the General Program of National Natural Science Foundation of China(NSFC)under Grant No.12374210+2 种基金the startup fund under Grant No.WIUCASQD2022005 from Wenzhou Institute University of Chinese Academy of Sciences(WIU-CAS)Z-CO-Y was supported by the Major Program of the NSFC under Grant No.22193032RP acknowledges the support of UCAS and funding from the Key Program of NSFC under Grant No.12034019.
文摘A mobile Coulomb gas permeating a fixed background crystalline lattice of charged colloidal crystals is subject to an electrostatic-elastic coupling,which we study on the continuum level by introducing a minimal coupling between electrostatic and displacement fields.We derive linearized,Debye–Hückel-like mean-field equations that can be analytically solved,incorporating the minimal coupling between electrostatic and displacement fields leading to an additional effective attractive interaction between mobile charges that depends in general on the strength of the coupling between the electrostatic and displacement fields.By analyzing the Gaussian fluctuations around the mean-field solution we also identify and quantify the region of its stability in terms of the electrostatic-elastic screening length.This detailed continuum theory incorporating the standard lattice elasticity and electrostatics of mobile charges provides a baseline to investigate the electrostatic-elastic coupling for microscopic models in colloid science and materials science.
基金financially supported by the National Natural Science Foundation of China(No.52377026 and No.52301192)Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)+4 种基金Postdoctoral Fellowship Program of CPSF under Grant Number(No.GZB20240327)Shandong Postdoctoral Science Foundation(No.SDCXZG-202400275)Qingdao Postdoctoral Application Research Project(No.QDBSH20240102023)China Postdoctoral Science Foundation(No.2024M751563)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites).
文摘Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent.Multi-component interface engineering is considered an effective means to achieve high-efficiency EMW absorption.However,interface modulation engineering has not been fully discussed and has great potential in the field of EMW absorption.In this study,multi-component tin compound fiber composites based on carbon fiber(CF)substrate were prepared by electrospinning,hydrothermal synthesis,and high-temperature thermal reduction.By utilizing the different properties of different substances,rich heterogeneous interfaces are constructed.This effectively promotes charge transfer and enhances interfacial polarization and conduction loss.The prepared SnS/SnS_(2)/SnO_(2)/CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt%in epoxy resin.The minimum reflection loss(RL)is−46.74 dB and the maximum effective absorption bandwidth is 5.28 GHz.Moreover,SnS/SnS_(2)/SnO_(2)/CF epoxy composite coatings exhibited long-term corrosion resistance on Q235 steel surfaces.Therefore,this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments.
基金financial support from the National Natural Science Foundation of China(52203123)the Sichuan Science and Technology Program(2023NSFSC0991)+2 种基金the State Key Laboratory of Polymer Materials Engineering(sklpme 2023-1-05 and sklpme 2024-2-04)the Fundamental Research Funds for the Central Universitiespartially sponsored by the Double First-Class Construction Funds of Sichuan University。
文摘Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundamental understanding on how they control the electrochemical performances.Herein,by harnessing the electrostatic adsorption of one-dimensional nanofiller(i.e.,surface-charged halloysite nanotubes,d-HNTs),we successfully fabricate a high-performance polymer nanocomposite electrolyte enabled by strong surface adsorption,referred as adsorption-state polymer electrolyte(ASPE).This ASPE shows fast ion transport(0.71±0.05 mS cm^(-1)at room temperature),high mechanical strength and toughness(10.3±0.05 MPa;15.73 MJ m^(-3)),improved lithium-ion transference number,and long cycle life with lithium metal anode,in comparison with the sample without the d-HNT adsorption effect.To fundamentally understand these high performances,an anion-rich asymmetric solvent structure model is further proposed and evidenced by both experiments and simulation studies.Results show that the electrostatic adsorption among the d-HNT,ionic liquid electrolyte,and polymer chain generates a nano filler-supported fast ion-conduction pathway with asymmetric Li+-coordination microenvironment.Meanwhile,the anion-rich asymmetric solvent structure model of ASPE also generates a fast de-solvation and anion-derived stable solid-electrolyte interphase for lithium metal anode.The high performance and understanding of the mechanism for ASPE provide a promising path to develop advanced polymer electrolytes.
基金Project supported by the National Natural Science Foundation of China (22301012)the R&D Program of Beijing Municipal Education Commission (KM202310011005)。
文摘Cerium oxide(CeO_(2)) has attracted much attention in recent years owing to its reversible switch ability in Ce^(3+)/Ce^(4+)redox to produce improved antioxidation properties for biomedical applications.Here,we report to embed the CeO_(2)nanospheres into the organic polymer network using electrostatic spinning technology to prepare polyvinyl alcohol(PVA)-encapsulated CeO_(2)nanospheres composite nanofibrous membranes(PVA-CeO_(2)) for the first time,which is beneficial to improving the dispersion and biocompatibility of CeO_(2)nanosphere without altering the original antioxidant properties of CeO_(2).Detailed characterization of the as-prepared composite nanofibrous membranes reveals that CeO_(2)was successfully introduced into the PVA fibers with strong interactions,thus enhancing the thermal stability and fracture toughness of the nanoifbers.As a result,PVA-CeO_(2)exhibits superior UV shielding performance,antioxidant performance and bacteriostatic performance.Meaningfully,PVA-CeO_(2)has strong absorbance in both UVA and UVB bands when the CeO_(2)concentration in the nanoifber membrane reaches 1.5 wt%,and shows an excellent scavenging effect on the 2,2-diphenyl-1-picrylhydrazyl(DPPH)radicals with a scavenging rate of 86.52%.Moreover,the Kirby-Bauer(K-B) method of agar diffusion test further confirms that PVA-CeO_(2)has antimicrobial ability against three types of representative strains,including Gram-positive bacteria(Staphylococcus aureus),Gram-negative bacteria(Escherichia coli) and fungi(Candida albicans).Importantly,no obvious cytotoxicity is observed for PVA-CeO_(2)even though the amount of embedded CeO_(2)nanosphere reaches as high as 1.5 wt%.This study reveals new avenues for improving the future smart design of CeO_(2)-based nanoifber membrane composite materials for biological antioxidants.
基金National Natural Science Foundation of China(No.22275150)。
文摘To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying method.The morphology,structure and thermal decomposition properties of the samples were analyzed using scanning electron microscopy(SEM),X-ray energy spectroscopy(EDS),infrared spectroscopy(FT-IR),and simultaneous thermal analyzer(TG-DSC).Additionally,the combustion process of the samples was tested using a high-speed camera.The results show that the addition of nano-Si contributes to the formation of composite explosives with regular morphology and smaller particle size.The Si/NC/CL-20 composite explosive has better and more uniform sphericity,with an average particle size of 73.4 nm,compared to the NC/CL-20 composite explosive.The Si/NC/CL-20 composite explosive which produced by the electrostatic spraying method,achieves physically uniform distribution of the components including NC,CL-20,Si.The addition of Si promotes the thermal decomposition of CL-20.In comparison to the NC/CL-20 composite explosive,the activation energy of the Si/NC/CL-20 composite explosive decreases by 16.78 kJ/mol,and the self-accelerated decomposition temperature and the critical temperature of thermal explosion decreases by 3.12 K and 2.61 K,respectively.Furthermore,Si/NC/CL-20 composite explosive has shorter ignition delay time and faster combustion rate compared to the NC/CL-20 composite explosive,which shows that Si can improve the combustion performance of CL-20.
基金financially supported by the National Key Research and Development Program of China(No.2022YFB3504200)the National Natural Science Foundation of China(Nos.U21A20326 and 22376063)+4 种基金the fund of the National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2020A05)the Fundamental Research Funds for the Central Universitiesthe funding received from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 897197.Y.L.(CSC No.202006740085)is grateful for thegrant from the China Scholarship Councilthe ICREA Academia program and grants MICINN/FEDER PID2021124572OB-C31 and GC 2021 SGR 01061part of Maria de Maeztu Units of Excellence Programme CEX2023-001300-M/funded by MCIN/AEI/https://doi.org/10.13039/501100011033
文摘Preferential oxidation of CO(CO-PROX)in H_(2)-rich streams is highly important for purifying the industrial grade H_(2)used in proton-exchange-membrane fuel cells(PEMFC),but it is still limited to a relatively narrow operation temperature window.In this study,the trace amounts of Cu are used to modify a Pt/Al_(2)O_(3)catalyst.The introduced Cu_(2+)species are atomically anchored on Pt nanoparticles through strong electrostatic adsorption.
基金supported by the National Natural Science Foundation of China(Grant No.52088101)the Space Utilization System of China Manned Space Engineering(Grant No.KJZ-YY-NCL02)+1 种基金the National Key R&D Program of China(Grant No.2021YFA0716301)the Shannxi Key Science and Technology Program(Grant Nos.2023-ZDLGY-36,2024JC-ZDXM-24).
文摘The liquid Zr_(100-x)V_(x)(x=8.6,16.5,30)alloys were undercooled to the maximum undercooling of 364 K(0.18 T_(L)),405 K(0.21 T_(L)),and 375 K(0.21 T_(L)),respectively,by using electrostatic levitation technique.The Zr_(91.4)V_(8.6) and Zr_(83.5)V_(16.5) alloys present only one recalescence during liquid/solid phase transition,while the Zr_(70)V_(30) alloy presents a transformation from two recalescence to one recalescence phenomenon with a critical undercooling of approximately 300 K.According to the LKT/BCT model,the calculated results of the primary β-Zr dendrite growth velocity in undercooled liquid Zr_(91.4)V_(8.6) and Zr_(83.5)V_(16.5) alloys agree well with the experiments.The velocity inflection points at 119 K of Zr_(91.4)V_(8.6) alloy and 201 K of Zr_(83.5)V_(16.5) alloy could be explained by the competition between solutal undercooling control and thermal undercooling control modes.For Zr_(70)V_(30) alloy solidified in the P1 with twice recalescence,a critical second undercooling of 253 K and corresponding undercooling of 65 and 244 K are obtained.When the un-dercooling is in the range of 65-244 K,the second undercooling would be greater than 253 K,and the residual liquid phase would solidify into anomalous eutectic microstructure for Zr_(70)V_(30) alloy.The Vickers hardness of Zr_(100-x)V_(x)(x=8.6,16.5,30)alloys all show a quadratic relationship with undercooling.Under electrostatic levitation condition,the mechanical property of Zr-V alloys could be significantly regulated through solidifying the alloys at different undercoolings.
基金The National Natural Science Foundation of China(No.51976039)。
文摘To explore the electrostatic discharge behavior of charged powders in industrial silos,discharge experiments are conducted based on a full-size industrial silo discharge platform.Electrostatic discharge mode,frequency,and energy are investigated for powders of different polarities.Although the powders have low charge-to-mass ratios(+0.087μC/kg for the positively charged powders and−0.26μC/kg for the negatively charged ones),electrostatic discharges occur approximately every 10 s,with the maximum discharge energy being 800 mJ.Powder polarity considerably influences discharge energy.The positive powders exhibit higher discharge energy than the negative ones,although discharge frequency remains similar for both.Effects of powder charge,humidity,and mass flow on discharge frequency and discharge energy are quantitatively analyzed,providing important insights for the improvement of safety in industrial powder handling.
基金support from the Instrument Developing Project of the Chinese Academy of Sciences (No.YJKYYQ20210003)Natural Science Foundation of Jilin Province (No. 20210101402JC)support from the National Natural Science Foundation of China (No. 22204159)。
文摘For nano-collision, regulating the interaction between nanoparticles(NPs) and electrode interfaces is crucial for the precise analysis of individual NPs. However, existing ultramicroelectrodes(UMEs) suffer from narrow electrochemical window and poor electrode interface adhesion, severely hindering the application of precise single NP analysis. Here, we propose a simple and effective interface modification strategy. By electrochemically self-assembling poly(diallyldimethylammonium chloride)(PC) on the surface of carbon nanocone electrodes(CNCEs), we successfully prepared PC-modified CNCEs(PC–CNCEs). These electrodes not only possess sufficiently wide electrochemical window but also exhibit strong adhesion to negatively charged Ag NPs on their surfaces. Surface physical analysis and electrochemical molecule detection validated the high-density loading of PC on the modified electrodes. Furthermore, the working principle of PC–CNCEs for single Ag NP collision detection was further verified through the techniques of nanocollision and double-potential steps. Leveraging these significant advantages, PC–CNCEs not only achieved precise measurements of single or mixed-sized Ag NPs but also detected Ag NP solutions at concentrations as low as fmol/L levels. This advancement offers a new strategy for the rapid and precise analysis of NP colloids.
基金Project supported by the China Postdoctoral Science Foundation (2023M731268)National Natural Science Foundation of China (51902029)Young Elite Scientists Sponsorship Program by CAST (2022QNRC001)。
文摘Lanthanum ferrite is a representative perovskite-structured rare earth-based bimetallic oxide,which has been widely studied in magnetic materials,sensors,catalysts and batteries.Herein,we designed and prepared polyoxometalate electron acceptor decorated LaFeO_(3)gas-sensitive composite materials with one-dimensional nanoribbons morphology by electrospinning.The effects of different mass fraction of Keggin type phosphotungstic acid(PW_(12)) on the gas-sensitive properties of LaFeO_(3)nanoribbons were investigated.The results show that the response value of LaFeO_(3)/PW_(12)sensor to acetone gas first increases and then decreases with the increase of PW_(12)content.The LaFeO_(3)/3%PW_(12)sensor exhibits a maximum response of 3.35-5 ppm acetone at 250℃,a 2.6 times increase in response value and a 90℃reduction in operating temperature compared to pure LaFeO_(3)nanoribbons.The LaFeO_(3)/3%PW_(12)sensor exhibits good linear relation in ppb-level concentrations and the lowest detection concentration is100 ppb.The sensors also show good repeatability in 6 tests and excellent long-term stability in 30 d.The improvement of the gas sensitive properties of the composite can be attributed to the synergistic effect between the two components.As an electron acceptor,PW_(12) promotes carrier migration between PW_(12)and LaFeO_(3),thereby improving the gas sensing performance of LaFeO_(3).This work promotes the practical application of polyoxometalate to promote rare earth-based gas sensitive materials in sensing field.
基金supported by National Natural Science Foundation of China(22309029,52404316)Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515140011,and 2024A1515110010)+2 种基金Dongguan Social Development Technology Foundation(Nos.20231800907933,and 20221800905122)Collaborative Innovation Center of Marine Science and Technology of Hainan University(No.XTCX2022HYC14)Start-up Research Foundation of Hainan University(No.KYQD(ZR)-23069).
文摘The notorious shuttle effect of polyiodides in aqueous Zinc-iodine(Zn-I2)batteries impedes their practical application,which renders it imperative to address this issue.Here,we report natural gelatin as an advanced aqueous binder for iodine-loading cathode to enable stable and efficient Zn-I_(2) batteries.The positively charged region in gelatin presents electrostatic attraction to the iodine species,while the electron-rich regions could donate electrons to form physical or even covalent bonds with iodine species,thus inhibiting polyiodides shuttle effect and boosting redox reaction.A high reversible capacity of 138 mAh g^(-1) after 3000 cycles at 2C and an ultra-long cycling stability of 30000 cycles at 25C with 107 mAh g^(-1) capacity was achieved.Gelatin binder also can accommodate high iodine-loading(~10 mg)cathode,punch cells,and severe temperature conditions(-10℃ and 60℃).In-situ UV-vis absorption spectroscopy,in-situ Raman spectra and theoretical calculation revealed the critical role of gelatin binder in suppressing polyiodide shuttling and accelerating reaction kinetics.This work uncovers the potential of natural low-cost binder material in advanced Zn-I_(2) batteries and drives future study of designing functional binders.
基金supported by National Natural Science Foundation of China(No.11975261)。
文摘In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion source.Through the finite element analysis method,the electrostatic analyses of insulators and grid plates were carried out,the material and structure parameters of insulators were determined.The maximum electric field around each insulator is about 4 kV/mm,and the maximum electric field between grids is about 14 kV/mm,which can meet the 120 keV withstand voltage holding.The insulation system for the positive ion source accelerator with 120 keV is designed,and the connection and basic parameters of insulators and support flanges are analyzed and determined.
基金supported by the National Natural Science Foundation of China(Nos.52377026 and 52301192)Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites).
文摘Magnetic metal has broad application prospects in the field of electromagnetic wave(EMW)absorption due to its excellent dielectric and magnetic properties.However,high density and poor chemical stability constrain their development potential.The combination of magnetic metals with other lightweight carbon materials is an effective solution.In this work,magnetic nanoparticle fiber composites were prepared by electrostatic spinning and high-temperature annealing processes.By adjusting the preparation process and annealing temperature,Co/Co7 Fe_(3)/CF-800 fiber composites containing double-shell hollow structured nanocubes were cleverly synthesized.The material is mixed with paraffin wax and has a minimum reflection loss(RL)of-52.14 dB and a maximum effective absorption bandwidth(EAB)of 6.16 GHz at a load of 10 wt%.By analyzing the electromagnetic parameters of the material,it was demonstrated that the material absorbs EMW through the synergistic effect of dielectric and magnetic losses.Electrochemical testing in a simulated seawater environment demonstrated that the material also has a degree of self-anticorrosion capability.This work provides new strategies for designing materials with excellent electromagnetic wave absorption and self-anticorrosion properties.
