Electrochemical oxidation/reduction of radicals is a green and environmentally friendly approach to generating fuels.These reactions,however,suffer from sluggish kinetics due to a low local concentration of radicals a...Electrochemical oxidation/reduction of radicals is a green and environmentally friendly approach to generating fuels.These reactions,however,suffer from sluggish kinetics due to a low local concentration of radicals around the electrocatalyst.A large applied electrode potential can enhance the fuel generation efficiency via enhancing the radical concentration around the electrocatalyst sites,but this comes at the cost of electricity.Here,we report about a~45%saving in energy to achieve an electrochemical hydrogen generation rate of 3×10^(16) molecules cm^(–2)s^(–1)(current density:10 mA/cm^(2))through localized electric field-induced enhancement in the reagent concentration(LEFIRC)at laser-induced periodic surface structured(LIPSS)electrodes.The finite element model is used to simulate the spatial distribution of the electric field to understand the effects of LIPSS geometric parameters in field localization.When the LIPSS patterned electrodes are used as substrates to support Pt/C and RuO_(2) electrocatalysts,the η_(10) overpotentials for HER and OER are decreased by 40.4 and 25%,respectively.Moreover,the capability of the LIPSS-patterned electrodes to operate at significantly reduced energy is also demonstrated in a range of electrolytes,including alkaline,acidic,neutral,and seawater.Importantly,when two LIPSS patterned electrodes were assembled as the anode and cathode into a cell,it requires 330 mVs of lower electric potential with enhanced stability over a similar cell made of pristine electrodes to drive a current density of 10 mA/cm^(2).This work demonstrates a physical and versatile approach of electrode surface patterning to boost electrocatalytic fuel generation performance and can be applied to any metal and semiconductor catalysts for a range of electrochemical reactions.展开更多
Development of robust electrocatalyst for oxygen reduction reaction(ORR)in a seawater electrolyte is the key to realize seawater electrolyte-based zinc-air batteries(SZABs).Herein,constructing a local electric field c...Development of robust electrocatalyst for oxygen reduction reaction(ORR)in a seawater electrolyte is the key to realize seawater electrolyte-based zinc-air batteries(SZABs).Herein,constructing a local electric field coupled with chloride ions(Cl-)fixation strategy in dual single-atom catalysts(DSACs)was proposed,and the resultant catalyst delivered considerable ORR performance in a seawater electrolyte,with a high half-wave potential(E_(1/2))of 0.868 V and a good maximum power density(Pmax)of 182 mW·cm^(−2)in the assembled SZABs,much higher than those of the Pt/C catalyst(E_(1/2):0.846 V;Pmax:150 mW·cm^(−2)).The in-situ characterization and theoretical calculations revealed that the Fe sites have a higher Cl^(−)adsorption affinity than the Co sites,and preferentially adsorbs Cl^(−)in a seawater electrolyte during the ORR process,and thus constructs a low-concentration Cl^(−)local microenvironment through the common-ion exclusion effect,which prevents Cl^(−)adsorption and corrosion in the Co active centers,achieving impressive catalytic stability.In addition,the directional charge movement between Fe and Co atomic pairs establishes a local electric field,optimizing the adsorption energy of Co sites for oxygen-containing intermediates,and further improving the ORR activity.展开更多
The slow-proton-fast-electron process severely limits the catalytic efficiency of oxygen evolution reaction.A method is proposed to accelerate proton transfer by building up local electric fields.Modifying acetic,etha...The slow-proton-fast-electron process severely limits the catalytic efficiency of oxygen evolution reaction.A method is proposed to accelerate proton transfer by building up local electric fields.Modifying acetic,ethanedioic and propanetricarboxylic(C_(6)H_(8)O_(6))ligands on BiVO_(4)surface results in a potential difference between BiVO_(4)and ligands that generates a local electric field which serves as a driving force for proton transfer.Among the ligands,carrying the strongest electron-withdrawing ability,the modification of C_(6)H_(8)O_(6) forms the strongest local electric field and leads to the fastest proton transfer and the smallest thermodynamic overpotential.C_(6)H_(8)O_(6)-BiVO_(4)exhibits 3.5 times photocurrent density as high as that of pure BiVO_(4),which is 3.50 mA cm^(-2)at 1.23 VRHE.The onset potential of C_(6)H_(8)O_(6)-BiVO_(4)shifts negatively from 0.70 to 0.38 VRHE.The mechanism for OER transitions from thermodynamically high energy proton-coupled electron transfer to thermodynamically low energy electron transfer as proton transfer is accelerated.展开更多
A plasma screening model that accounts for electronic exchange-correlation effects and ionic nonideality in dense quantum plasmas is proposed.This model can be used as an input in various plasma interaction models to ...A plasma screening model that accounts for electronic exchange-correlation effects and ionic nonideality in dense quantum plasmas is proposed.This model can be used as an input in various plasma interaction models to calculate scattering cross-sections and transport properties.The applicability of the proposed plasma screening model is demonstrated using the example of the temperature relaxation rate in dense hydrogen and warm dense aluminum.Additionally,the conductivity of warm dense aluminum is computed in the regime where collisions are dominated by electron-ion scattering.The results obtained are compared with available theoretical results and simulation data.展开更多
Graphene has great potential for enhancing light−matter interactions in a two-dimensional regime due to surface plasmons with low loss and strong light confinement.Further utilization of graphene in nanophotonics reli...Graphene has great potential for enhancing light−matter interactions in a two-dimensional regime due to surface plasmons with low loss and strong light confinement.Further utilization of graphene in nanophotonics relies on the precise control of light localization properties.Here,we demonstrate the tailoring of electromagnetic field localizations in the mid-infrared region by precisely shaping the graphene into nanostructures with different geometries.We generalize the phenomenological cavity model and employ nanoimaging techniques to quantitatively calculate and experimentally visualize the two-dimensional electromagnetic field distributions within the nanostructures,which indicate that the electromagnetic field can be shaped into specific patterns depending on the shapes and sizes of the nanostructures.Furthermore,we show that the light localization performance can be further improved by reducing the sizes of the nanostructures,where a lateral confinement of λ0/180 of the incidence light can be achieved.The electromagnetic field localizations within a nanostructure with a specific geometry can also be modulated by chemical doping.Our strategies can,in principle,be generalized to other two-dimensional materials,therefore providing new degrees of freedom for designing nanophotonic components capable of tailoring two-dimensional light confinement over a broad wavelength range.展开更多
Source localization by matched-field processing （MFP） can be accelerated by building a database of Green＇s functions which however requires a bulk-storage memory. According to the sparsity of the source locations i...Source localization by matched-field processing （MFP） can be accelerated by building a database of Green＇s functions which however requires a bulk-storage memory. According to the sparsity of the source locations in the search grids of MFP, compressed sensing inspires an approach to reduce the database by introducing a sensing matrix to compress the database. Compressed sensing is further used to estimate the source locations with higher resolution by solving the β -norm optimization problem of the compressed Green＇s function and the data received by a vertieal/horizontal line array. The method is validated by simulation and is verified with the experimental data.展开更多
We investigate the localization of a five-dimensional vector field on a pure geometrical thick brahe. By introducing two types of interactions between the vector field and the background scalar field, we obtain a typi...We investigate the localization of a five-dimensional vector field on a pure geometrical thick brahe. By introducing two types of interactions between the vector field and the background scalar field, we obtain a typical volcano potential for the first type of coupling and a Posehl-Teller potential for the second one. These two types of couplings guarantee that the vector zero mode can be localized on the pure geometrical thick brahe under certain conditions.展开更多
Besides the diverse investigations on the interactions between intense laser fields and molecular systems,extensive research has been recently dedicated to exploring the response of nanosystems excited by well-tailore...Besides the diverse investigations on the interactions between intense laser fields and molecular systems,extensive research has been recently dedicated to exploring the response of nanosystems excited by well-tailored femtosecond laser fields.Due to the fact that nanostructures hold peculiar effects when illuminated by laser pulses,the underlying mechanisms and the corresponding potential applications can make significant improvements in both fundamental research and development of novel techniques.In this review,we provide a summarization of the strong field ionization occurring on the surface of nanosystems.The molecules attached to the nanoparticle surface perform as the precursor in the ionization and excitation of the whole nanosystem,the fundamental processes of which are yet to be discovered.We discuss the influence on nanoparticle constituents,geometric shapes and sizes,as well as the specific waveforms of the excitation laser fields.The intriguing characteristics observed in surface ion emission reflect how enhanced near field affects the localized ionizations and nanoplasma expansions,thereby paving the way for further precision controls on the light-and-matter interactions in the extreme spatial temporal levels.展开更多
Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Cu...Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.展开更多
Among the existing research on the treatment of disorders of consciousness(DOC),deep brain stimulation(DBS)offers a highly promising therapeutic approach.This comprehensive review documents the historical development ...Among the existing research on the treatment of disorders of consciousness(DOC),deep brain stimulation(DBS)offers a highly promising therapeutic approach.This comprehensive review documents the historical development of DBS and its role in the treatment of DOC,tracing its progression from an experimental therapy to a detailed modulation approach based on the mesocircuit model hypothesis.The mesocircuit model hypothesis suggests that DOC arises from disruptions in a critical network of brain regions,providing a framework for refining DBS targets.We also discuss the multimodal approaches for assessing patients with DOC,encompassing clinical behavioral scales,electrophysiological assessment,and neuroimaging techniques methods.During the evolution of DOC therapy,the segmentation of central nuclei,the recording of single-neurons,and the analysis of local field potentials have emerged as favorable technical factors that enhance the efficacy of DBS treatment.Advances in computational models have also facilitated a deeper exploration of the neural dynamics associated with DOC,linking neuron-level dynamics with macroscopic behavioral changes.Despite showing promising outcomes,challenges remain in patient selection,precise target localization,and the determination of optimal stimulation parameters.Future research should focus on conducting large-scale controlled studies to delve into the pathophysiological mechanisms of DOC.It is imperative to further elucidate the precise modulatory effects of DBS on thalamo-cortical and cortico-cortical functional connectivity networks.Ultimately,by optimizing neuromodulation strategies,we aim to substantially enhance therapeutic outcomes and greatly expedite the process of consciousness recovery in patients.展开更多
The long-term enhancement in glutamate receptor mediated excitatory responses has been observed in stroke model. This pathological form of plasticity, termed post-ischemic long-term potentiation （i-LTP）, points to f...The long-term enhancement in glutamate receptor mediated excitatory responses has been observed in stroke model. This pathological form of plasticity, termed post-ischemic long-term potentiation （i-LTP）, points to functional reorganization after stroke. Little is known, however, about whether and how this i-LTP would affect subsequent induction of synaptic plasticity. Here, we first directly confirmed that i-LTP was induced in the endothelin-l-induced ischemia model as in other in vitro models. We also demonstrated increased expression of NR2B, CaMKII and p-CaMKII, which are reminiscent of i-LTP. We further induced LTP of field excitatory post- synaptic potentials （fEPSPs） on CA1 hippocampal neurons in peri-infarct regions of the endothelin-l-induced mini-stroke model. We found that LTP of fEPSPs, induced by high-frequency stimulation, displayed a progressive impairment at 12 and 24 hours after ischemia. Moreover, using in vivo multi-channel recording, we found that the local field potential, which represents electrical property of cell ensembles in more restricted regions, was also dam- pened at these two time points. These results suggest that i-LTP elevates the induction threshold of subsequent synap- tic plasticity. Our data helps to deepen the knowledge of meta-synaptic regulation of plasticity after focal ischemia.展开更多
The main contents in this note are: 1. introduction; 2. locally compact groups and local fields; 3. calculus on fractals based upon local fields; 4. fractional calculus and fractals; 5. fractal function spaces and PDE...The main contents in this note are: 1. introduction; 2. locally compact groups and local fields; 3. calculus on fractals based upon local fields; 4. fractional calculus and fractals; 5. fractal function spaces and PDE on fractals.展开更多
The capability and reliability are crucial characteristics of mobile robots while navigating in complex environments. These robots are expected to perform many useful tasks which can improve the quality of life greatl...The capability and reliability are crucial characteristics of mobile robots while navigating in complex environments. These robots are expected to perform many useful tasks which can improve the quality of life greatly. Robot localization and decisionmaking are the most important cognitive processes during navigation. However, most of these algorithms are not efficient and are challenging tasks while robots navigate through complex environments. In this paper,we propose a biologically inspired method for robot decision-making, based on rat’s brain signals. Rodents accurately and rapidly navigate in complex spaces by localizing themselves in reference to the surrounding environmental landmarks. Firstly, we analyzed the rats’ strategies while navigating in the complex Y-maze, and recorded local field potentials(LFPs), simultaneously.The recorded LFPs were processed and different features were extracted which were used as the input in the artificial neural network(ANN) to predict the rat’s decision-making in each junction. The ANN performance was tested in a real robot and good performance is achieved. The implementation of our method on a real robot, demonstrates its abilities to imitate the rat’s decision-making and integrate the internal states with external sensors, in order to perform reliable navigation in complex maze.展开更多
Wavelet frames have gained considerable popularity during the past decade, primarily due to their substantiated applications in diverse and widespread fields of science and engineering. Finding general and verifiable ...Wavelet frames have gained considerable popularity during the past decade, primarily due to their substantiated applications in diverse and widespread fields of science and engineering. Finding general and verifiable conditions which imply that the wavelet systems are wavelet frames is among the core problems in time-frequency analysis. In this article, we establish some new inequalities for wavelet frames on local fields of positive characteristic by means of the Fourier transform. As an application, an improved version of the Li-Jiang inequality for wavelet frames on local fields is obtained.展开更多
The formation of shear bands in metallic glasses(MGs)was examined by tailoring localized complex stress fields(LCSFs).The findings have shown that the LCSFs in MGs can increase the localization of strained atoms and a...The formation of shear bands in metallic glasses(MGs)was examined by tailoring localized complex stress fields(LCSFs).The findings have shown that the LCSFs in MGs can increase the localization of strained atoms and accelerate the release of accumulated deformation energy for initiating a shear band in confined and thin-layered regions.The findings not only add more knowledge to the formation mechanisms of shear bands in MGs,but also provide possible rationale for the discrepancies in the mechanical properties of different-sized MGs.As compared with the bulk samples,the higher strength and larger elastic limits in nanoscaled MGs could be attributed to the elimination of stress-concentrators,which can serve as LCSFs.展开更多
We theoretically investigate surface plasmon resonance properties in Au and Ag cubic nanoparticles and find a novel plasmonic mode that exhibits simultaneous low extinction and high local field enhancement properties....We theoretically investigate surface plasmon resonance properties in Au and Ag cubic nanoparticles and find a novel plasmonic mode that exhibits simultaneous low extinction and high local field enhancement properties. We analyse this mode from different aspects by looking at the distribution patterns of local field intensity, energy flux, absorption and charge density. We find that in the mode the polarized charge is highly densified in a very limited volume around the corner of the nanocube and results in very strong local field enhancement. Perturbations of the incident energy flux and light absorption are also strongly localized in this small volume of the corner region, leading to both low absorption and low scattering cross section. As a result, the extinction is low for the mode. Metal nanoparticles involving such peculiar modes may be useful for constructing nonlinear compound materials with low linear absorption and high nonlinearity.展开更多
This paper investigates the effect of Lorentz local field correction （LFC） on the propagation of ultrashort laser pulses in a para-nitroaniline molecular medium under resonant and nonresonant conditions by solving n...This paper investigates the effect of Lorentz local field correction （LFC） on the propagation of ultrashort laser pulses in a para-nitroaniline molecular medium under resonant and nonresonant conditions by solving numerically the full-wave Maxwell-Bloch equations beyond slowly-varying envelope approximation and rotating-wave approximation. The effect of the LFC is considerably obvious when pulses with large areas propagate in the dense molecular medium. In the case of resonance, the group velocity of the sub-pulses split from the incident pulse along propagation is severely decreased by the LFC, especially for the latest sub-pulse. However, in the case of nonresonance, the influence of the LFC on the temporal evolution of the pulse is less obvious and lacks homogeneity with an increase in incident pulse area, propagation distance and molecular density.展开更多
Working memory plays an important role in human cognition. This study investigated how working memory was encoded by the power of multichannel local field potentials （LFPs） based on sparse non negative matrix factor...Working memory plays an important role in human cognition. This study investigated how working memory was encoded by the power of multichannel local field potentials （LFPs） based on sparse non negative matrix factorization （SNMF）. SNMF was used to extract features from LFPs recorded from the prefrontal cortex of four SpragueDawley rats during a memory task in a Y maze, with 10 trials for each rat. Then the powerincreased LFP components were selected as working memoryrelated features and the other components were removed. After that, the inverse operation of SNMF was used to study the encoding of working memory in the time frequency domain. We demonstrated that theta and gamma power increased significantly during the working memory task. The results suggested that postsynaptic activity was simulated well by the sparse activity model. The theta and gamma bands were meaningful for encoding working memory.展开更多
We establish the construction theory of function based upon a local field Kp as underlying space. By virture of the concept of pseudo-differential operator, we introduce ＂fractal calculus＂ （or, p-type calculus, or,...We establish the construction theory of function based upon a local field Kp as underlying space. By virture of the concept of pseudo-differential operator, we introduce ＂fractal calculus＂ （or, p-type calculus, or, Gibbs-Butzer calculus）. Then, show the Jackson direct approximation theorems, Bermstein inverse approximation theorems and the equivalent approximation theorems for compact group D（C Kp） and locally compact group Kp^＋-（= Kp）, so that the foundation of construction theory of function on local fields is established. Moreover, the Jackson type, Bernstein type, and equivalent approximation theorems on the HOlder-type space C^σ（Kp）, σ 〉0, are proved; then the equivalent approximation theorem on Sobolev-type space Wr（Kp）, σ≥0, 1≤r 〈∞, is shown.展开更多
In order to enhance the p-type doping concentration in the LBSF, boron was added into the aluminum paste and boron doped local back surface field（B-LBSF） was successfully fabricated in this work. Through boron dopin...In order to enhance the p-type doping concentration in the LBSF, boron was added into the aluminum paste and boron doped local back surface field（B-LBSF） was successfully fabricated in this work. Through boron doping in the LBSF, much higher doping concentration was observed for the B-LBSF over the Al-LBSF. Higher doping concentration in the LBSF is expected to lead to better rear passivation and lower rear contact resistance. Based on one thousand pieces of solar cells for each type, it was found that the rear passivated crystalline silicon solar cells with B-LBSF showed statistical improvement in their photovoltaic properties over those with Al-LBSF.展开更多
基金National Natural Science Foundation of China (grant nos.62134009,62121005)the Innovation Grant of Changchun Institute of Optics,Fine Mechanics and Physics (CIOMP),Jilin Provincial Science and Technology Development Project (grant no:YDZJ202102CXJD002)Bill&Melinda Gates Foundation (grant no:OPP1157723)
文摘Electrochemical oxidation/reduction of radicals is a green and environmentally friendly approach to generating fuels.These reactions,however,suffer from sluggish kinetics due to a low local concentration of radicals around the electrocatalyst.A large applied electrode potential can enhance the fuel generation efficiency via enhancing the radical concentration around the electrocatalyst sites,but this comes at the cost of electricity.Here,we report about a~45%saving in energy to achieve an electrochemical hydrogen generation rate of 3×10^(16) molecules cm^(–2)s^(–1)(current density:10 mA/cm^(2))through localized electric field-induced enhancement in the reagent concentration(LEFIRC)at laser-induced periodic surface structured(LIPSS)electrodes.The finite element model is used to simulate the spatial distribution of the electric field to understand the effects of LIPSS geometric parameters in field localization.When the LIPSS patterned electrodes are used as substrates to support Pt/C and RuO_(2) electrocatalysts,the η_(10) overpotentials for HER and OER are decreased by 40.4 and 25%,respectively.Moreover,the capability of the LIPSS-patterned electrodes to operate at significantly reduced energy is also demonstrated in a range of electrolytes,including alkaline,acidic,neutral,and seawater.Importantly,when two LIPSS patterned electrodes were assembled as the anode and cathode into a cell,it requires 330 mVs of lower electric potential with enhanced stability over a similar cell made of pristine electrodes to drive a current density of 10 mA/cm^(2).This work demonstrates a physical and versatile approach of electrode surface patterning to boost electrocatalytic fuel generation performance and can be applied to any metal and semiconductor catalysts for a range of electrochemical reactions.
基金supported by the National Natural Science Foundation of China(52164028,52274297)the Start-up Research Foundation of Hainan University(KYQD(ZR)20008,KYQD(ZR)21125,KYQD(ZR)23169))+1 种基金Collaborative Innovation Center of Marine Science and Technology of Hainan University(XTCX2022HYC14)Innovative Research Project for Postgraduate Students in Hainan Province(Qhyb2024-95).
文摘Development of robust electrocatalyst for oxygen reduction reaction(ORR)in a seawater electrolyte is the key to realize seawater electrolyte-based zinc-air batteries(SZABs).Herein,constructing a local electric field coupled with chloride ions(Cl-)fixation strategy in dual single-atom catalysts(DSACs)was proposed,and the resultant catalyst delivered considerable ORR performance in a seawater electrolyte,with a high half-wave potential(E_(1/2))of 0.868 V and a good maximum power density(Pmax)of 182 mW·cm^(−2)in the assembled SZABs,much higher than those of the Pt/C catalyst(E_(1/2):0.846 V;Pmax:150 mW·cm^(−2)).The in-situ characterization and theoretical calculations revealed that the Fe sites have a higher Cl^(−)adsorption affinity than the Co sites,and preferentially adsorbs Cl^(−)in a seawater electrolyte during the ORR process,and thus constructs a low-concentration Cl^(−)local microenvironment through the common-ion exclusion effect,which prevents Cl^(−)adsorption and corrosion in the Co active centers,achieving impressive catalytic stability.In addition,the directional charge movement between Fe and Co atomic pairs establishes a local electric field,optimizing the adsorption energy of Co sites for oxygen-containing intermediates,and further improving the ORR activity.
文摘The slow-proton-fast-electron process severely limits the catalytic efficiency of oxygen evolution reaction.A method is proposed to accelerate proton transfer by building up local electric fields.Modifying acetic,ethanedioic and propanetricarboxylic(C_(6)H_(8)O_(6))ligands on BiVO_(4)surface results in a potential difference between BiVO_(4)and ligands that generates a local electric field which serves as a driving force for proton transfer.Among the ligands,carrying the strongest electron-withdrawing ability,the modification of C_(6)H_(8)O_(6) forms the strongest local electric field and leads to the fastest proton transfer and the smallest thermodynamic overpotential.C_(6)H_(8)O_(6)-BiVO_(4)exhibits 3.5 times photocurrent density as high as that of pure BiVO_(4),which is 3.50 mA cm^(-2)at 1.23 VRHE.The onset potential of C_(6)H_(8)O_(6)-BiVO_(4)shifts negatively from 0.70 to 0.38 VRHE.The mechanism for OER transitions from thermodynamically high energy proton-coupled electron transfer to thermodynamically low energy electron transfer as proton transfer is accelerated.
基金funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan Grant No.AP19678033“The study of the transport and optical properties of hydrogen at high pressure.”。
文摘A plasma screening model that accounts for electronic exchange-correlation effects and ionic nonideality in dense quantum plasmas is proposed.This model can be used as an input in various plasma interaction models to calculate scattering cross-sections and transport properties.The applicability of the proposed plasma screening model is demonstrated using the example of the temperature relaxation rate in dense hydrogen and warm dense aluminum.Additionally,the conductivity of warm dense aluminum is computed in the regime where collisions are dominated by electron-ion scattering.The results obtained are compared with available theoretical results and simulation data.
基金supported by the National Natural Science Foundation of China(Grant Nos.51290271,11474364 and 51290273)the National Key Basic Research Program of China(Grant Nos.2013CB933601 and 2013YQ12034506)the Guangdong Natural Science Funds for Distinguished Young Scholars(Grant No.2014A030306017)。
文摘Graphene has great potential for enhancing light−matter interactions in a two-dimensional regime due to surface plasmons with low loss and strong light confinement.Further utilization of graphene in nanophotonics relies on the precise control of light localization properties.Here,we demonstrate the tailoring of electromagnetic field localizations in the mid-infrared region by precisely shaping the graphene into nanostructures with different geometries.We generalize the phenomenological cavity model and employ nanoimaging techniques to quantitatively calculate and experimentally visualize the two-dimensional electromagnetic field distributions within the nanostructures,which indicate that the electromagnetic field can be shaped into specific patterns depending on the shapes and sizes of the nanostructures.Furthermore,we show that the light localization performance can be further improved by reducing the sizes of the nanostructures,where a lateral confinement of λ0/180 of the incidence light can be achieved.The electromagnetic field localizations within a nanostructure with a specific geometry can also be modulated by chemical doping.Our strategies can,in principle,be generalized to other two-dimensional materials,therefore providing new degrees of freedom for designing nanophotonic components capable of tailoring two-dimensional light confinement over a broad wavelength range.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11374271 and 11374270the Fundamental Research Funds for the Central Universities under Grant No 201513038
文摘Source localization by matched-field processing （MFP） can be accelerated by building a database of Green＇s functions which however requires a bulk-storage memory. According to the sparsity of the source locations in the search grids of MFP, compressed sensing inspires an approach to reduce the database by introducing a sensing matrix to compress the database. Compressed sensing is further used to estimate the source locations with higher resolution by solving the β -norm optimization problem of the compressed Green＇s function and the data received by a vertieal/horizontal line array. The method is validated by simulation and is verified with the experimental data.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11522541 and 11375075the Fundamental Research Funds for the Central Universities under Grant Nos lzujbky-2016-k04 and lzujbky-2014-31
文摘We investigate the localization of a five-dimensional vector field on a pure geometrical thick brahe. By introducing two types of interactions between the vector field and the background scalar field, we obtain a typical volcano potential for the first type of coupling and a Posehl-Teller potential for the second one. These two types of couplings guarantee that the vector zero mode can be localized on the pure geometrical thick brahe under certain conditions.
基金Project supported by the National Natural Science Fundation of China (Grant Nos.92050105,92250301,and 12227807)。
文摘Besides the diverse investigations on the interactions between intense laser fields and molecular systems,extensive research has been recently dedicated to exploring the response of nanosystems excited by well-tailored femtosecond laser fields.Due to the fact that nanostructures hold peculiar effects when illuminated by laser pulses,the underlying mechanisms and the corresponding potential applications can make significant improvements in both fundamental research and development of novel techniques.In this review,we provide a summarization of the strong field ionization occurring on the surface of nanosystems.The molecules attached to the nanoparticle surface perform as the precursor in the ionization and excitation of the whole nanosystem,the fundamental processes of which are yet to be discovered.We discuss the influence on nanoparticle constituents,geometric shapes and sizes,as well as the specific waveforms of the excitation laser fields.The intriguing characteristics observed in surface ion emission reflect how enhanced near field affects the localized ionizations and nanoplasma expansions,thereby paving the way for further precision controls on the light-and-matter interactions in the extreme spatial temporal levels.
基金supported by the National Natural Science Foundation of China,No.82071254(to WZ).
文摘Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.
基金supported by the Science and Technology Innovation 2030(2022ZD0205300)the International(Hong Kong,Macao,and Taiwan)Science and Technology Cooperation Project(Z221100002722014)+5 种基金the 2022 Open Project of Key Laboratory and Engineering Technology Research of the Ministry of Civil Affairs(2022GKZS0003)the Chinese Institute for Brain Research Youth Scholar Program(2022-NKX-XM-02)the Natural Science Foundation of Beijing municipality(7232049)the General Program of National Natural Science Foundation of China(82371197)the FundRef Organization name of Guarantors of Brain(HMR04170)the Royal Society(IES\R3\213123).
文摘Among the existing research on the treatment of disorders of consciousness(DOC),deep brain stimulation(DBS)offers a highly promising therapeutic approach.This comprehensive review documents the historical development of DBS and its role in the treatment of DOC,tracing its progression from an experimental therapy to a detailed modulation approach based on the mesocircuit model hypothesis.The mesocircuit model hypothesis suggests that DOC arises from disruptions in a critical network of brain regions,providing a framework for refining DBS targets.We also discuss the multimodal approaches for assessing patients with DOC,encompassing clinical behavioral scales,electrophysiological assessment,and neuroimaging techniques methods.During the evolution of DOC therapy,the segmentation of central nuclei,the recording of single-neurons,and the analysis of local field potentials have emerged as favorable technical factors that enhance the efficacy of DBS treatment.Advances in computational models have also facilitated a deeper exploration of the neural dynamics associated with DOC,linking neuron-level dynamics with macroscopic behavioral changes.Despite showing promising outcomes,challenges remain in patient selection,precise target localization,and the determination of optimal stimulation parameters.Future research should focus on conducting large-scale controlled studies to delve into the pathophysiological mechanisms of DOC.It is imperative to further elucidate the precise modulatory effects of DBS on thalamo-cortical and cortico-cortical functional connectivity networks.Ultimately,by optimizing neuromodulation strategies,we aim to substantially enhance therapeutic outcomes and greatly expedite the process of consciousness recovery in patients.
基金supported by Major State Basic Research Program of China(Grant No.2013CB733801)
文摘The long-term enhancement in glutamate receptor mediated excitatory responses has been observed in stroke model. This pathological form of plasticity, termed post-ischemic long-term potentiation （i-LTP）, points to functional reorganization after stroke. Little is known, however, about whether and how this i-LTP would affect subsequent induction of synaptic plasticity. Here, we first directly confirmed that i-LTP was induced in the endothelin-l-induced ischemia model as in other in vitro models. We also demonstrated increased expression of NR2B, CaMKII and p-CaMKII, which are reminiscent of i-LTP. We further induced LTP of field excitatory post- synaptic potentials （fEPSPs） on CA1 hippocampal neurons in peri-infarct regions of the endothelin-l-induced mini-stroke model. We found that LTP of fEPSPs, induced by high-frequency stimulation, displayed a progressive impairment at 12 and 24 hours after ischemia. Moreover, using in vivo multi-channel recording, we found that the local field potential, which represents electrical property of cell ensembles in more restricted regions, was also dam- pened at these two time points. These results suggest that i-LTP elevates the induction threshold of subsequent synap- tic plasticity. Our data helps to deepen the knowledge of meta-synaptic regulation of plasticity after focal ischemia.
文摘The main contents in this note are: 1. introduction; 2. locally compact groups and local fields; 3. calculus on fractals based upon local fields; 4. fractional calculus and fractals; 5. fractal function spaces and PDE on fractals.
基金supported by the Japanese Government,Grants-in-Aid for Scientific Research 2014 to 2016 under Grant No.26330296
文摘The capability and reliability are crucial characteristics of mobile robots while navigating in complex environments. These robots are expected to perform many useful tasks which can improve the quality of life greatly. Robot localization and decisionmaking are the most important cognitive processes during navigation. However, most of these algorithms are not efficient and are challenging tasks while robots navigate through complex environments. In this paper,we propose a biologically inspired method for robot decision-making, based on rat’s brain signals. Rodents accurately and rapidly navigate in complex spaces by localizing themselves in reference to the surrounding environmental landmarks. Firstly, we analyzed the rats’ strategies while navigating in the complex Y-maze, and recorded local field potentials(LFPs), simultaneously.The recorded LFPs were processed and different features were extracted which were used as the input in the artificial neural network(ANN) to predict the rat’s decision-making in each junction. The ANN performance was tested in a real robot and good performance is achieved. The implementation of our method on a real robot, demonstrates its abilities to imitate the rat’s decision-making and integrate the internal states with external sensors, in order to perform reliable navigation in complex maze.
基金supported by NBHM, Department of Atomic Energy, Government of India (Grant No. 2/48(8)/2016/NBHM(R.P)/R&D II/13924)
文摘Wavelet frames have gained considerable popularity during the past decade, primarily due to their substantiated applications in diverse and widespread fields of science and engineering. Finding general and verifiable conditions which imply that the wavelet systems are wavelet frames is among the core problems in time-frequency analysis. In this article, we establish some new inequalities for wavelet frames on local fields of positive characteristic by means of the Fourier transform. As an application, an improved version of the Li-Jiang inequality for wavelet frames on local fields is obtained.
基金financially supported by the National Natural Science Foundation of China(Nos.51801049 and 51801174)the State Key Laboratory of Metastable Materials Science and Technology,Yanshan University(No.201809)the Fundamental Research Funds for the Central Universities of China(Nos.PA2019GDZC0096 and JD2019JGPY0015)。
文摘The formation of shear bands in metallic glasses(MGs)was examined by tailoring localized complex stress fields(LCSFs).The findings have shown that the LCSFs in MGs can increase the localization of strained atoms and accelerate the release of accumulated deformation energy for initiating a shear band in confined and thin-layered regions.The findings not only add more knowledge to the formation mechanisms of shear bands in MGs,but also provide possible rationale for the discrepancies in the mechanical properties of different-sized MGs.As compared with the bulk samples,the higher strength and larger elastic limits in nanoscaled MGs could be attributed to the elimination of stress-concentrators,which can serve as LCSFs.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60736041 and 10874238)the National Key Basic Research Special Foundation of China (Grant No. 2007CB613205)
文摘We theoretically investigate surface plasmon resonance properties in Au and Ag cubic nanoparticles and find a novel plasmonic mode that exhibits simultaneous low extinction and high local field enhancement properties. We analyse this mode from different aspects by looking at the distribution patterns of local field intensity, energy flux, absorption and charge density. We find that in the mode the polarized charge is highly densified in a very limited volume around the corner of the nanocube and results in very strong local field enhancement. Perturbations of the incident energy flux and light absorption are also strongly localized in this small volume of the corner region, leading to both low absorption and low scattering cross section. As a result, the extinction is low for the mode. Metal nanoparticles involving such peculiar modes may be useful for constructing nonlinear compound materials with low linear absorption and high nonlinearity.
基金supported by the National Natural Science Foundation of China (Grant No. 10974121)the National Basic Research Program of China (Grant No. 2006CB806000)the Open Fund of the State Key Laboratory of High Field Laser Physics(Shanghai Institute of Optics and Fine Mechanics)
文摘This paper investigates the effect of Lorentz local field correction （LFC） on the propagation of ultrashort laser pulses in a para-nitroaniline molecular medium under resonant and nonresonant conditions by solving numerically the full-wave Maxwell-Bloch equations beyond slowly-varying envelope approximation and rotating-wave approximation. The effect of the LFC is considerably obvious when pulses with large areas propagate in the dense molecular medium. In the case of resonance, the group velocity of the sub-pulses split from the incident pulse along propagation is severely decreased by the LFC, especially for the latest sub-pulse. However, in the case of nonresonance, the influence of the LFC on the temporal evolution of the pulse is less obvious and lacks homogeneity with an increase in incident pulse area, propagation distance and molecular density.
基金supported by the National Natural Science Foundation of China (61074131 and 91132722)the Doctoral Fund of the Ministry of Education of China (21101202110007)
文摘Working memory plays an important role in human cognition. This study investigated how working memory was encoded by the power of multichannel local field potentials （LFPs） based on sparse non negative matrix factorization （SNMF）. SNMF was used to extract features from LFPs recorded from the prefrontal cortex of four SpragueDawley rats during a memory task in a Y maze, with 10 trials for each rat. Then the powerincreased LFP components were selected as working memoryrelated features and the other components were removed. After that, the inverse operation of SNMF was used to study the encoding of working memory in the time frequency domain. We demonstrated that theta and gamma power increased significantly during the working memory task. The results suggested that postsynaptic activity was simulated well by the sparse activity model. The theta and gamma bands were meaningful for encoding working memory.
文摘We establish the construction theory of function based upon a local field Kp as underlying space. By virture of the concept of pseudo-differential operator, we introduce ＂fractal calculus＂ （or, p-type calculus, or, Gibbs-Butzer calculus）. Then, show the Jackson direct approximation theorems, Bermstein inverse approximation theorems and the equivalent approximation theorems for compact group D（C Kp） and locally compact group Kp^＋-（= Kp）, so that the foundation of construction theory of function on local fields is established. Moreover, the Jackson type, Bernstein type, and equivalent approximation theorems on the HOlder-type space C^σ（Kp）, σ 〉0, are proved; then the equivalent approximation theorem on Sobolev-type space Wr（Kp）, σ≥0, 1≤r 〈∞, is shown.
基金Funded by the National Natural Science Foundation of China(61366004)the Research Fund for the Doctoral Program of Higher Education(20123601110006)the Jiangxi Provincial Department of Education(KJLD13008)
文摘In order to enhance the p-type doping concentration in the LBSF, boron was added into the aluminum paste and boron doped local back surface field（B-LBSF） was successfully fabricated in this work. Through boron doping in the LBSF, much higher doping concentration was observed for the B-LBSF over the Al-LBSF. Higher doping concentration in the LBSF is expected to lead to better rear passivation and lower rear contact resistance. Based on one thousand pieces of solar cells for each type, it was found that the rear passivated crystalline silicon solar cells with B-LBSF showed statistical improvement in their photovoltaic properties over those with Al-LBSF.
