Electrons in the energy range of 10–100 keV are important energetic particle components in the magnetosphere,and they play a key role in many physical processes in the magnetosphere.However,many scientific questions ...Electrons in the energy range of 10–100 keV are important energetic particle components in the magnetosphere,and they play a key role in many physical processes in the magnetosphere.However,many scientific questions about these processes are still unanswered.High spatiotemporal and energy-resolution imaging detection of 10–100 keV electrons is of great significance for solving these scientific problems.The traditional space particle detection technology cannot effectively detect the medium-energy electrons in this energy range.In this project,we propose combining low-noise particle detection technology with pinhole imaging technology to achieve high-resolution imaging detection of 10–100 keV medium-energy electrons in the magnetosphere,and at the same time achieve miniaturization(≤3.2 kg and size of 150×150×170 mm)and low power consumption(≤5 W)of the instrument,which can be used for space physics research and space weather applications in the future.展开更多
The triple bond in N_(2)has an extremely high bond energy and is thus difficult to break.N_(2)is commonly converted into NH3 artificially via the Haber-Bosch process,and NH_(3)can be utilized to produce other nitrogen...The triple bond in N_(2)has an extremely high bond energy and is thus difficult to break.N_(2)is commonly converted into NH3 artificially via the Haber-Bosch process,and NH_(3)can be utilized to produce other nitrogen-containing chemicals.Here,we developed an electron catalyzed method to directly fix N_(2)into azos,by pushing and pulling the electron into and from the aromatic halide with the cyclic voltammetry method.The round-trip journey of electron can successfully weaken the triple bond in N_(2)through the electron pushing-induced aryl radical via a“brick trowel”transition state,and then produce the diazonium ions by pulling the electron out from the diazo radical intermediate.Different azos can be synthesized with this developed electron catalyzed approach.This approach provides a novel concept and practical route for the fixation of N_(2)at atmospheric pressure into chemical products valuable for industrial and commercial applications.展开更多
The features of optical defects in a chemical vapor deposition (CVD) synthetic type Ⅱ a diamond were characterized using photoluminescence (PL) spectroscopy, before and after electron irradiation. The sample was cut ...The features of optical defects in a chemical vapor deposition (CVD) synthetic type Ⅱ a diamond were characterized using photoluminescence (PL) spectroscopy, before and after electron irradiation. The sample was cut within a {100} growth layer, and irradiated with 2 MeV electrons along the <100> axis. PL spectra of sample were collected under 532 nm and 355 nm laser excitation, at room temperature and 77 K, and linear scanning analysis along incident depth was applied to determine the distribution of defects. The pre-irradiation characterization results revealed uniformly distributed PL centers at 389 nm, 469 nm, 533 nm, 575 nm (ZPL of NV 0), 637 nm (ZPL of NV -), and 736.7/737.1 nm (ZPL doublet of SiV -). After irradiation, the differential responses of these as-grown defects were observed, alongside the emergence of irradiation-induced defects, namely 489 nm center, H3 center (ZPL at 504 nm) and GR1 center (ZPL at 741 nm). The maximum penetration depth of 2 MeV electron-irradiation induced defects was determined to be 2.1 mm. This work primarily presents the depth profiles of both as-grown and irradiation-induced defects in 2 MeV electrons irradiated diamond. The result provides experimental data for better understanding of the radiation effect in diamonds. Serving as a reference for diamond enhancement by electron irradiation.展开更多
The gold nano-plates(Au NPLs)have been extensively studied for their high quality factor as mechanical resonators.But it remains still unclear how the thickness and morphology of Au NPLs affect the hot electron diffus...The gold nano-plates(Au NPLs)have been extensively studied for their high quality factor as mechanical resonators.But it remains still unclear how the thickness and morphology of Au NPLs affect the hot electron diffusion.Here we have employed transient absorption microscopy to gain spatiotemporal imaging of the hot electron diffusion in Au NPLs.Au NPLs of varying thickness over 200 nm were synthesized.It was found that the hot electron diffusion of Au NPL excited at the boundary is obviously faster than that excited at the internal surface.And thinner Au NPLs exhibit a faster hot electron diffusion rate compared to thicker Au NPLs.Because the time constant of hot electron cooling(electron-phonon coupling)is independent of the excited position and thickness of Au NPLs,the effect of electron-phonon coupling on hot electron diffusion should be ruled out.So the hot electron diffusion rate is highly dimensionality-dependent.The quasi-one-dimensional diffusion along the boundary of nanoplate has the fastest rate of 50 cm^(2)/s,and the three-dimensional diffusion has the slowest rate of 22 cm^(2)/s.The fundamental investigation on the hot electrons transport property of Au NPLs offers a new insight for designing metal-based optoelectronic devices.展开更多
The propagation properties of ion-acoustic solitary and shock waves in the magnetized viscous plasma with nonthermal trapped electrons are investigated.The Cairns-Gurevich distribution as the electron distribution is ...The propagation properties of ion-acoustic solitary and shock waves in the magnetized viscous plasma with nonthermal trapped electrons are investigated.The Cairns-Gurevich distribution as the electron distribution is considered to describe the plasma nonthermality and particle trapping.By adopting the reductive perturbation technique,we derived the nonlinear Schamel-Korteweg-de Vries-Burgers(SKdVB)equation,and then obtained the ion-acoustic shock and solitary wave solutions of the SKdVB equation for different limiting cases.It is found that the impact of nonthermal parameterα,external magnetic fieldΩ,obliqueness lz,wave speed U0,and the ion kinematic viscosityη0can significantly change the characteristics of the shock and solitary waves.These results may be useful for better understanding the propagation of nonlinear structures in space(i.e.Earth's magnetosphere and ionosphere,auroral regions)and laboratory plasma with nonthermal trapped electrons.展开更多
The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Eff...The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities.Herein,the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten(W)sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst.The presence of W enables the electron transfer from Pt,which promotes electron rearrangement in the Pt-5d orbitals.It not only optimizes the adsorption of H^(*) and CO^(*)on Pt,but also the OH^(*) intermediates adsorbed on the W sites oxidize the CO*adsorbed on Pt,thereby retaining more active sites for H_(2) adsorption and oxidation.The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C,and the limiting current density decreases by only 3.4%after introducing 1000 ppm CO in H_(2).Notably,the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations.The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.展开更多
Stretchable electronics have been recognized as intriguing next-generation electronics that possess huge market value,and stretchable electronic conductors(SECs)are essential for stretchable electronics,which not only...Stretchable electronics have been recognized as intriguing next-generation electronics that possess huge market value,and stretchable electronic conductors(SECs)are essential for stretchable electronics,which not only can serve as critical functional components but also are the indispensable electronic connections bridging various electronic components within stretchable electronic systems.Herein,we offer a comprehensive review of recent progress in SECs including the material categories,structure designs,fabrication techniques,and applications.The characteristics,performance enhancement strategies,and application requirements are emphasized.Based on the recent advances,the existing challenges and future prospects are outlined and discussed.展开更多
Permeable electronics promise improved physiological comfort,but remain constrained by limited functional integration and poor mechanical robustness.Here,we report a three-dimensional(3D)permeable electronic system th...Permeable electronics promise improved physiological comfort,but remain constrained by limited functional integration and poor mechanical robustness.Here,we report a three-dimensional(3D)permeable electronic system that overcomes these challenges by combining electrospun SEBS nanofiber mats,high-resolution liquid metal conductors patterned via thermal imprinting(50μm),and a strain isolators(SIL)that protects vertical interconnects(VIAs)from stress concentration.This architecture achieves ultrahigh air permeability(>5.09 m L cm^(-2)min^(-1)),exceptional stretchability(750%fracture strain),and reliable conductivity maintained through more than 32,500 strain cycles.Leveraging these advances,we have integrated multilayer circuits,strain sensors,and a three-axis accelerometer to achieve a fully integrated,stretchable,permeable wireless real-time gesture recognition glove.The system enables accurate sign language interpretation(98%)and seamless robotic hand control,demonstrating its potential for assistive technologies.By uniting comfort,durability,and high-density integration,this work establishes a versatile platform for nextgeneration wearable electronics and interactive human-robot interfaces.展开更多
AlGaN-based deep-ultraviolet(DUV)laser diodes(LDs)face performance challenges due to elec-tron leakage and poor hole injection which is often worsened by polarization effects from conventional elec-tron blocking layer...AlGaN-based deep-ultraviolet(DUV)laser diodes(LDs)face performance challenges due to elec-tron leakage and poor hole injection which is often worsened by polarization effects from conventional elec-tron blocking layers(EBLs).To overcome these limitations,we propose an EBL-free DUV LD design incor-porating a 1-nm undoped Al_(0.8)Ga_(0.2)N thin strip layer after the last quantum barrier.Using PICS3D simula-tions,we evaluate the optical and electrical characteristics.Results show a significant increase in effective electron barrier height(from 158.2 meV to 420.7 meV)and a reduction in hole barrier height(from 149.2 meV to 62.8 meV),which enhance hole injection and reduce electron leakage.The optimized structure(LD3)achieves a 14%increase in output power,improved slope efficiency(1.85 W/A),and lower threshold current.This design also reduces the quantum confined Stark effect and forms dual hole accumulation regions,im-proving recombination efficiency.展开更多
The effects of initial spin orientation on the final electron beam polarization in laser wakefield acceleration in a pre-polarized plasma are investigated theoretically and numerically.From the results of variation of...The effects of initial spin orientation on the final electron beam polarization in laser wakefield acceleration in a pre-polarized plasma are investigated theoretically and numerically.From the results of variation of the initial spin direction,the spin dynamics of the electron beam are found to depend on the self-injection mechanism.The effects of wakefields and laser fields are studied using test particle dynamics and particle-in-cell simulations based on the Thomas-Bargmann-Michel-Telegdi equation.Compared with transverse injection,longitudinal injection is found to be preferable for obtaining a highly polarized electron beam.展开更多
Flexible polymer electronics have emerged as an important research frontier in materials science due to their unique advantages,including mechanical flexibility,lightweight characteristics,and solution processability....Flexible polymer electronics have emerged as an important research frontier in materials science due to their unique advantages,including mechanical flexibility,lightweight characteristics,and solution processability.These features enable a wide range of emerging applications such as wearable electronics,electronic skins,and biomedical devices,etc.In recent years,much advances in polymer chemistry,device physics,and interface engineering have significantly improved the performance of flexible polymer electronic devices,accelerating their transition from fundamental research to practical applications.展开更多
The discovery of pressure-induced superconducting electrides has sparked a intense wave of interest in novel superconductors.However,opinions vary regarding the relationship between non-nuclear attractors(NNAs)and sup...The discovery of pressure-induced superconducting electrides has sparked a intense wave of interest in novel superconductors.However,opinions vary regarding the relationship between non-nuclear attractors(NNAs)and superconductivity,with two opposing views currently represented by the materials Li_(6)P and Li_(6)C.Here,we choose the ternary Li–C–P as a model system and reveal the underlying mechanism by which NNAs contribute to superconductivity.The loosely bound NNAs in the superlithide Li_(14)CP covalently bond with Li and form unique satellite interstitial electrons(SIEs)around Li near the Fermi level,dominating the superconductivity.First-principles calculations show that the SIEs progressively increase in number and couple strongly with phonons at high pressure.Moreover,the Fermi surface nesting associated with SIEs induces phonon softening,further enhancing the electron–phonon coupling and giving the superlithide Li_(14)CP a T_(c)of 10.6 K at 300 GPa.The leading role of SIEs in superconductivity is a general one and is also relevant to the recently predicted Li_(6)P and Li_(6)C.Our work presented here reshapes the understanding of NNA-dominated superconductivity and holds promise for guiding future discoveries and designs of novel high-temperature superconductors.展开更多
The rapid advancement of machine learning based tight-binding Hamiltonian(MLTB)methods has opened new avenues for efficient and accurate electronic structure simulations,particularly in large-scale systems and long-ti...The rapid advancement of machine learning based tight-binding Hamiltonian(MLTB)methods has opened new avenues for efficient and accurate electronic structure simulations,particularly in large-scale systems and long-time scenarios.This review begins with a concise overview of traditional tight-binding(TB)models,including both(semi-)empirical and first-principles approaches,establishing the foundation for understanding MLTB developments.We then present a systematic classification of existing MLTB methodologies,grouped into two major categories:direct prediction of TB Hamiltonian elements and inference of empirical parameters.A comparative analysis with other ML-based electronic structure models is also provided,highlighting the advancement of MLTB approaches.Finally,we explore the emerging MLTB application ecosystem,highlighting how the integration of MLTB models with a diverse suite of post-processing tools from linear-scaling solvers to quantum transport frameworks and molecular dynamics interfaces is essential for tackling complex scientific problems across different domains.The continued advancement of this integrated paradigm promises to accelerate materials discovery and open new frontiers in the predictive simulation of complex quantum phenomena.展开更多
Traditional digitizers for signal readout of PET detectors are based on commercial analog-to-digital converters(ADC).However,the cost and power consumption of an entire electronic readout system based on digitizers fo...Traditional digitizers for signal readout of PET detectors are based on commercial analog-to-digital converters(ADC).However,the cost and power consumption of an entire electronic readout system based on digitizers for a PET scanner are high.To address this problem,a soft-core ADC based on a field-programmable gate array(FPGA)was proposed.An FPGA-based ADC(FPGA-ADC)combines low loss and high performance.To achieve good performance,the FPGA-ADC requires three calibrations:time-to-digital converter(TDC)length calibration,TDC alignment calibration,and TDC-to-ADC calibration.A prototype front-end electronics based on FPGA-ADC was built to evaluate the performance of time-of-flight positron emission tomography(TOF PET)detectors.Each PET detector consists of a LYSO crystal single-ended coupled to a silicon photomultiplier(SiPM).The experimental results show that the full-width at half-maximum(FWHM)energy resolution for 511 keV gamma photons after saturation correction of the SiPM was 12.3%.The FWHM coincidence timing resolution(CTR)of the TOF PET detector with the readout of the front-end electronic prototype is 385.2 ps.FPGA-ADCbased front-end electronics are very promising for multichannel,low-cost,highly integrated,and power-efficient readout electronic systems for radiation detector applications.展开更多
A rapidly growing field is piezoresistive sensor for accurate respiration rate monitoring to suppress the worldwide respiratory illness.However,a large neglected issue is the sensing durability and accuracy without in...A rapidly growing field is piezoresistive sensor for accurate respiration rate monitoring to suppress the worldwide respiratory illness.However,a large neglected issue is the sensing durability and accuracy without interference since the expiratory pressure always coupled with external humidity and temperature variations,as well as mechanical motion artifacts.Herein,a robust and biodegradable piezoresistive sensor is reported that consists of heterogeneous MXene/cellulose-gelation sensing layer and Ag-based interdigital electrode,featuring customizable cylindrical interface arrangement and compact hierarchical laminated architecture for collectively regulating the piezoresistive response and mechanical robustness,thereby realizing the long-term breath-induced pressure detection.Notably,molecular dynamics simulations reveal the frequent angle inversion and reorientation of MXene/cellulose in vacuum filtration,driven by shear forces and interfacial interactions,which facilitate the establishment of hydrogen bonds and optimize the architecture design in sensing layer.The resultant sensor delivers unprecedented collection features of superior stability for off-axis deformation(0-120°,~2.8×10^(-3) A)and sensing accuracy without crosstalk(humidity 50%-100%and temperature 30-80).Besides,the sensor-embedded mask together with machine learning models is achieved to train and classify the respiration status for volunteers with different ages(average prediction accuracy~90%).It is envisioned that the customizable architecture design and sensor paradigm will shed light on the advanced stability of sustainable electronics and pave the way for the commercial application in respiratory monitory.展开更多
Electron beam injectors are pivotal components of large-scale scientific instruments,such as synchrotron radiation sources,free-electron lasers,and electron-positron colliders.The quality of the electron beam produced...Electron beam injectors are pivotal components of large-scale scientific instruments,such as synchrotron radiation sources,free-electron lasers,and electron-positron colliders.The quality of the electron beam produced by the injector critically influences the performance of the entire accelerator-based scientific research apparatus.The injectors of such facilities usually use photocathode and thermionic-cathode electron guns.Although the photocathode injector can produce electron beams of excellent quality,its associated laser system is massive and intricate.The thermionic-cathode electron gun,especially the gridded electron gun injector,has a simple structure capable of generating numerous electron beams.However,its emittance is typically high.In this study,methods to reduce beam emittance are explored through a comprehensive analysis of various grid structures and preliminary design results,examining the evolution of beam phase space at different grid positions.An optimization method for reducing the emittance of a gridded thermionic-cathode electron gun is proposed through theoretical derivation,electromagnetic-field simulation,and beam-dynamics simulation.A 50%reduction in emittance was achieved for a 50 keV,1.7 A electron gun,laying the foundation for the subsequent design of a high-current,low-emittance injector.展开更多
SiO_(2)–CaO–Al_(2)O_(3)ternary inclusions are among the most common complex oxide inclusions in steel.Nevertheless,the chemical and physical properties of these composite inclusions,particularly with detailed compos...SiO_(2)–CaO–Al_(2)O_(3)ternary inclusions are among the most common complex oxide inclusions in steel.Nevertheless,the chemical and physical properties of these composite inclusions,particularly with detailed composition changes,have not been sufficiently investigated.In this study,first-principles density functional theory calculations were used to determine the electronic,mechanical,and thermodynamic properties of two stable phases in the SiO_(2)–CaO–Al_(2)O_(3)ternary inclusion system:anorthite(CaAl_(2)Si_(2)O_(8))and gehlenite(Ca_(2)Al_(2)SiO_(7)).Based on the electronic density of states analysis and band structure calculations,oxygen atoms play important roles in the electron reactivity of both phases.Young’s modulus and Poisson’s ratios were calculated and compared with those of the SiO_(2)–CaO inclusions.The Young’s moduli of CaAl_(2)Si_(2)O_(8)(101.32 GPa)and Ca_(2)Al_(2)SiO_(7)(131.43 GPa)were close to the maximum and minimum Young’s moduli of the binary oxide inclusions,respectively.With increasing temperature,the Young’s moduli of CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)showed slight increasing and decreasing trends,respectively,whereas the Poisson’s ratio decreased.Furthermore,the thermodynamic properties,particularly temperature-related thermal expansion coefficients,were also deeply investigated.The thermal expansion coefficients of both CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)increased rapidly with increasing temperature in the low-temperature regime above 300K.As the temperature increased,the increasing trend slowed.When the temperature reached 2000 K,the thermal expansion coefficients of CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)respectively were 12×10^(−6)and 8.5×10^(−6)K^(−1).These findings enhance the understanding of the physical nature of ternary inclusions in steels and provide a scientific foundation for analyzing their effects on steel performance using a more comprehensive inclusion database,thereby contributing to inclusion engineering in the development of materials with superior mechanical integrity.展开更多
Achieving high-energy density remains a key objective for advanced energy storage systems.However,challenges,such as poor cathode conductivity,anode dendrite formation,polysulfide shuttling,and electrolyte degradation...Achieving high-energy density remains a key objective for advanced energy storage systems.However,challenges,such as poor cathode conductivity,anode dendrite formation,polysulfide shuttling,and electrolyte degradation,continue to limit performance and stability.Molecular and ionic dipole interactions have emerged as an effective strategy to address these issues by regulating ionic transport,modulating solvation structures,optimizing interfacial chemistry,and enhancing charge transfer kinetics.These interactions also stabilize electrode interfaces,suppress side reactions,and mitigate anode corrosion,collectively improving the durability of high-energy batteries.A deeper understanding of these mechanisms is essential to guide the design of next-generation battery materials.Herein,this review summarizes the development,classification,and advantages of dipole interactions in high-energy batteries.The roles of dipoles,including facilitating ion transport,controlling solvation dynamics,stabilizing the electric double layer,optimizing solid electrolyte interphase and cathode–electrolyte interface layers,and inhibiting parasitic reactions—are comprehensively discussed.Finally,perspectives on future research directions are proposed to advance dipole-enabled strategies for high-performance energy storage.This review aims to provide insights into the rational design of dipole-interactive systems and promote the progress of electrochemical energy storage technologies.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42274225)the International Science and Technology Cooperation Project of the Ningbo Key R&D Program(Grant No.2024H031).
文摘Electrons in the energy range of 10–100 keV are important energetic particle components in the magnetosphere,and they play a key role in many physical processes in the magnetosphere.However,many scientific questions about these processes are still unanswered.High spatiotemporal and energy-resolution imaging detection of 10–100 keV electrons is of great significance for solving these scientific problems.The traditional space particle detection technology cannot effectively detect the medium-energy electrons in this energy range.In this project,we propose combining low-noise particle detection technology with pinhole imaging technology to achieve high-resolution imaging detection of 10–100 keV medium-energy electrons in the magnetosphere,and at the same time achieve miniaturization(≤3.2 kg and size of 150×150×170 mm)and low power consumption(≤5 W)of the instrument,which can be used for space physics research and space weather applications in the future.
文摘The triple bond in N_(2)has an extremely high bond energy and is thus difficult to break.N_(2)is commonly converted into NH3 artificially via the Haber-Bosch process,and NH_(3)can be utilized to produce other nitrogen-containing chemicals.Here,we developed an electron catalyzed method to directly fix N_(2)into azos,by pushing and pulling the electron into and from the aromatic halide with the cyclic voltammetry method.The round-trip journey of electron can successfully weaken the triple bond in N_(2)through the electron pushing-induced aryl radical via a“brick trowel”transition state,and then produce the diazonium ions by pulling the electron out from the diazo radical intermediate.Different azos can be synthesized with this developed electron catalyzed approach.This approach provides a novel concept and practical route for the fixation of N_(2)at atmospheric pressure into chemical products valuable for industrial and commercial applications.
基金This work is supported by National Natural Science Foundation of China(No.42372054)。
文摘The features of optical defects in a chemical vapor deposition (CVD) synthetic type Ⅱ a diamond were characterized using photoluminescence (PL) spectroscopy, before and after electron irradiation. The sample was cut within a {100} growth layer, and irradiated with 2 MeV electrons along the <100> axis. PL spectra of sample were collected under 532 nm and 355 nm laser excitation, at room temperature and 77 K, and linear scanning analysis along incident depth was applied to determine the distribution of defects. The pre-irradiation characterization results revealed uniformly distributed PL centers at 389 nm, 469 nm, 533 nm, 575 nm (ZPL of NV 0), 637 nm (ZPL of NV -), and 736.7/737.1 nm (ZPL doublet of SiV -). After irradiation, the differential responses of these as-grown defects were observed, alongside the emergence of irradiation-induced defects, namely 489 nm center, H3 center (ZPL at 504 nm) and GR1 center (ZPL at 741 nm). The maximum penetration depth of 2 MeV electron-irradiation induced defects was determined to be 2.1 mm. This work primarily presents the depth profiles of both as-grown and irradiation-induced defects in 2 MeV electrons irradiated diamond. The result provides experimental data for better understanding of the radiation effect in diamonds. Serving as a reference for diamond enhancement by electron irradiation.
基金supported by the National Natural Science Foundation of China(No.22273006).
文摘The gold nano-plates(Au NPLs)have been extensively studied for their high quality factor as mechanical resonators.But it remains still unclear how the thickness and morphology of Au NPLs affect the hot electron diffusion.Here we have employed transient absorption microscopy to gain spatiotemporal imaging of the hot electron diffusion in Au NPLs.Au NPLs of varying thickness over 200 nm were synthesized.It was found that the hot electron diffusion of Au NPL excited at the boundary is obviously faster than that excited at the internal surface.And thinner Au NPLs exhibit a faster hot electron diffusion rate compared to thicker Au NPLs.Because the time constant of hot electron cooling(electron-phonon coupling)is independent of the excited position and thickness of Au NPLs,the effect of electron-phonon coupling on hot electron diffusion should be ruled out.So the hot electron diffusion rate is highly dimensionality-dependent.The quasi-one-dimensional diffusion along the boundary of nanoplate has the fastest rate of 50 cm^(2)/s,and the three-dimensional diffusion has the slowest rate of 22 cm^(2)/s.The fundamental investigation on the hot electrons transport property of Au NPLs offers a new insight for designing metal-based optoelectronic devices.
文摘The propagation properties of ion-acoustic solitary and shock waves in the magnetized viscous plasma with nonthermal trapped electrons are investigated.The Cairns-Gurevich distribution as the electron distribution is considered to describe the plasma nonthermality and particle trapping.By adopting the reductive perturbation technique,we derived the nonlinear Schamel-Korteweg-de Vries-Burgers(SKdVB)equation,and then obtained the ion-acoustic shock and solitary wave solutions of the SKdVB equation for different limiting cases.It is found that the impact of nonthermal parameterα,external magnetic fieldΩ,obliqueness lz,wave speed U0,and the ion kinematic viscosityη0can significantly change the characteristics of the shock and solitary waves.These results may be useful for better understanding the propagation of nonlinear structures in space(i.e.Earth's magnetosphere and ionosphere,auroral regions)and laboratory plasma with nonthermal trapped electrons.
基金supported by the National Natural Science Foundation of China(22179034,22279030)the Natural Science Foundation of Heilongjiang Province(ZD2023B002).
文摘The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities.Herein,the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten(W)sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst.The presence of W enables the electron transfer from Pt,which promotes electron rearrangement in the Pt-5d orbitals.It not only optimizes the adsorption of H^(*) and CO^(*)on Pt,but also the OH^(*) intermediates adsorbed on the W sites oxidize the CO*adsorbed on Pt,thereby retaining more active sites for H_(2) adsorption and oxidation.The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C,and the limiting current density decreases by only 3.4%after introducing 1000 ppm CO in H_(2).Notably,the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations.The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.
基金supported by the National Natural Science Foundation of China(52172170)Guangdong Natural Science Foundation for Distinguished Young Scholars(2023B1515020114)+2 种基金Fundamental Research Funds for the Central Universities(24lgqb003)Guangdong University Innovation and Enhancement Program(2024KTSCX003)Science and Technology Projects of Guangzhou(2025A04J4230).
文摘Stretchable electronics have been recognized as intriguing next-generation electronics that possess huge market value,and stretchable electronic conductors(SECs)are essential for stretchable electronics,which not only can serve as critical functional components but also are the indispensable electronic connections bridging various electronic components within stretchable electronic systems.Herein,we offer a comprehensive review of recent progress in SECs including the material categories,structure designs,fabrication techniques,and applications.The characteristics,performance enhancement strategies,and application requirements are emphasized.Based on the recent advances,the existing challenges and future prospects are outlined and discussed.
基金supported in part by the National Key R&D Program of China under Grant 2024YFB4405300 and 2022YFA1204300the Natural Science Foundation of Hunan Province under Grant 2023JJ20016+2 种基金the National Natural Science Foundation of China under Grants of 52221001 and 62090035the Key Research and Development Plan of Hunan Province under grants of 2022GK3002 and 2023GK2012the Key Program of Science and Technology Department of Hunan Province under grant of 2020XK2001。
文摘Permeable electronics promise improved physiological comfort,but remain constrained by limited functional integration and poor mechanical robustness.Here,we report a three-dimensional(3D)permeable electronic system that overcomes these challenges by combining electrospun SEBS nanofiber mats,high-resolution liquid metal conductors patterned via thermal imprinting(50μm),and a strain isolators(SIL)that protects vertical interconnects(VIAs)from stress concentration.This architecture achieves ultrahigh air permeability(>5.09 m L cm^(-2)min^(-1)),exceptional stretchability(750%fracture strain),and reliable conductivity maintained through more than 32,500 strain cycles.Leveraging these advances,we have integrated multilayer circuits,strain sensors,and a three-axis accelerometer to achieve a fully integrated,stretchable,permeable wireless real-time gesture recognition glove.The system enables accurate sign language interpretation(98%)and seamless robotic hand control,demonstrating its potential for assistive technologies.By uniting comfort,durability,and high-density integration,this work establishes a versatile platform for nextgeneration wearable electronics and interactive human-robot interfaces.
文摘AlGaN-based deep-ultraviolet(DUV)laser diodes(LDs)face performance challenges due to elec-tron leakage and poor hole injection which is often worsened by polarization effects from conventional elec-tron blocking layers(EBLs).To overcome these limitations,we propose an EBL-free DUV LD design incor-porating a 1-nm undoped Al_(0.8)Ga_(0.2)N thin strip layer after the last quantum barrier.Using PICS3D simula-tions,we evaluate the optical and electrical characteristics.Results show a significant increase in effective electron barrier height(from 158.2 meV to 420.7 meV)and a reduction in hole barrier height(from 149.2 meV to 62.8 meV),which enhance hole injection and reduce electron leakage.The optimized structure(LD3)achieves a 14%increase in output power,improved slope efficiency(1.85 W/A),and lower threshold current.This design also reduces the quantum confined Stark effect and forms dual hole accumulation regions,im-proving recombination efficiency.
基金supported by the National Natural Science Foundation of China(Grant Nos.11804348,11775056,11975154,12225505,and 12405281)the Science Challenge(Project No.TZ2018005)+2 种基金supported by the Shanghai Pujiang Program(Grant No.23PJ1414600)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0890203)supported by the Accelerator Technology Helmholtz Infrastructure consortium ATHENA.
文摘The effects of initial spin orientation on the final electron beam polarization in laser wakefield acceleration in a pre-polarized plasma are investigated theoretically and numerically.From the results of variation of the initial spin direction,the spin dynamics of the electron beam are found to depend on the self-injection mechanism.The effects of wakefields and laser fields are studied using test particle dynamics and particle-in-cell simulations based on the Thomas-Bargmann-Michel-Telegdi equation.Compared with transverse injection,longitudinal injection is found to be preferable for obtaining a highly polarized electron beam.
文摘Flexible polymer electronics have emerged as an important research frontier in materials science due to their unique advantages,including mechanical flexibility,lightweight characteristics,and solution processability.These features enable a wide range of emerging applications such as wearable electronics,electronic skins,and biomedical devices,etc.In recent years,much advances in polymer chemistry,device physics,and interface engineering have significantly improved the performance of flexible polymer electronic devices,accelerating their transition from fundamental research to practical applications.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Natural Science Foundation of China(Grant Nos.12374004 and 12174141)the High Performance Computing Center of Jilin University,China。
文摘The discovery of pressure-induced superconducting electrides has sparked a intense wave of interest in novel superconductors.However,opinions vary regarding the relationship between non-nuclear attractors(NNAs)and superconductivity,with two opposing views currently represented by the materials Li_(6)P and Li_(6)C.Here,we choose the ternary Li–C–P as a model system and reveal the underlying mechanism by which NNAs contribute to superconductivity.The loosely bound NNAs in the superlithide Li_(14)CP covalently bond with Li and form unique satellite interstitial electrons(SIEs)around Li near the Fermi level,dominating the superconductivity.First-principles calculations show that the SIEs progressively increase in number and couple strongly with phonons at high pressure.Moreover,the Fermi surface nesting associated with SIEs induces phonon softening,further enhancing the electron–phonon coupling and giving the superlithide Li_(14)CP a T_(c)of 10.6 K at 300 GPa.The leading role of SIEs in superconductivity is a general one and is also relevant to the recently predicted Li_(6)P and Li_(6)C.Our work presented here reshapes the understanding of NNA-dominated superconductivity and holds promise for guiding future discoveries and designs of novel high-temperature superconductors.
基金supported by the Advanced Materials-National Science and Technology Major Project(Grant No.2025ZD0618401)the National Natural Science Foundation of China(Grant No.12504285)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20250472)NFSG grant from BITS-Pilani,Dubai campus。
文摘The rapid advancement of machine learning based tight-binding Hamiltonian(MLTB)methods has opened new avenues for efficient and accurate electronic structure simulations,particularly in large-scale systems and long-time scenarios.This review begins with a concise overview of traditional tight-binding(TB)models,including both(semi-)empirical and first-principles approaches,establishing the foundation for understanding MLTB developments.We then present a systematic classification of existing MLTB methodologies,grouped into two major categories:direct prediction of TB Hamiltonian elements and inference of empirical parameters.A comparative analysis with other ML-based electronic structure models is also provided,highlighting the advancement of MLTB approaches.Finally,we explore the emerging MLTB application ecosystem,highlighting how the integration of MLTB models with a diverse suite of post-processing tools from linear-scaling solvers to quantum transport frameworks and molecular dynamics interfaces is essential for tackling complex scientific problems across different domains.The continued advancement of this integrated paradigm promises to accelerate materials discovery and open new frontiers in the predictive simulation of complex quantum phenomena.
基金supported by the Key R&D Program of Shandong Province(No.2023SFGC0101)Shandong Excellent Young Scientists Fund Program(Overseas)(No.2023HWYQ-047)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2022QA039)the National Natural Science Foundation of China(NSFC)(No.U2106202).
文摘Traditional digitizers for signal readout of PET detectors are based on commercial analog-to-digital converters(ADC).However,the cost and power consumption of an entire electronic readout system based on digitizers for a PET scanner are high.To address this problem,a soft-core ADC based on a field-programmable gate array(FPGA)was proposed.An FPGA-based ADC(FPGA-ADC)combines low loss and high performance.To achieve good performance,the FPGA-ADC requires three calibrations:time-to-digital converter(TDC)length calibration,TDC alignment calibration,and TDC-to-ADC calibration.A prototype front-end electronics based on FPGA-ADC was built to evaluate the performance of time-of-flight positron emission tomography(TOF PET)detectors.Each PET detector consists of a LYSO crystal single-ended coupled to a silicon photomultiplier(SiPM).The experimental results show that the full-width at half-maximum(FWHM)energy resolution for 511 keV gamma photons after saturation correction of the SiPM was 12.3%.The FWHM coincidence timing resolution(CTR)of the TOF PET detector with the readout of the front-end electronic prototype is 385.2 ps.FPGA-ADCbased front-end electronics are very promising for multichannel,low-cost,highly integrated,and power-efficient readout electronic systems for radiation detector applications.
基金supported by the National Natural Science Foundation of China(22074072,22274083,52376199)the Shandong Provincial Natural Science Foundation(ZR2023LZY005)+1 种基金the Exploration Project of the State Key Laboratory of BioFibers and EcoTextiles of Qingdao University(TSKT202101)the Fundamental Research Funds for the Central Universities(2022BLRD13,2023BLRD01).
文摘A rapidly growing field is piezoresistive sensor for accurate respiration rate monitoring to suppress the worldwide respiratory illness.However,a large neglected issue is the sensing durability and accuracy without interference since the expiratory pressure always coupled with external humidity and temperature variations,as well as mechanical motion artifacts.Herein,a robust and biodegradable piezoresistive sensor is reported that consists of heterogeneous MXene/cellulose-gelation sensing layer and Ag-based interdigital electrode,featuring customizable cylindrical interface arrangement and compact hierarchical laminated architecture for collectively regulating the piezoresistive response and mechanical robustness,thereby realizing the long-term breath-induced pressure detection.Notably,molecular dynamics simulations reveal the frequent angle inversion and reorientation of MXene/cellulose in vacuum filtration,driven by shear forces and interfacial interactions,which facilitate the establishment of hydrogen bonds and optimize the architecture design in sensing layer.The resultant sensor delivers unprecedented collection features of superior stability for off-axis deformation(0-120°,~2.8×10^(-3) A)and sensing accuracy without crosstalk(humidity 50%-100%and temperature 30-80).Besides,the sensor-embedded mask together with machine learning models is achieved to train and classify the respiration status for volunteers with different ages(average prediction accuracy~90%).It is envisioned that the customizable architecture design and sensor paradigm will shed light on the advanced stability of sustainable electronics and pave the way for the commercial application in respiratory monitory.
基金supported by the Hundred-person Program of Chinese Academy of Sciences and the National Natural Science Foundation of China(No.11905074).
文摘Electron beam injectors are pivotal components of large-scale scientific instruments,such as synchrotron radiation sources,free-electron lasers,and electron-positron colliders.The quality of the electron beam produced by the injector critically influences the performance of the entire accelerator-based scientific research apparatus.The injectors of such facilities usually use photocathode and thermionic-cathode electron guns.Although the photocathode injector can produce electron beams of excellent quality,its associated laser system is massive and intricate.The thermionic-cathode electron gun,especially the gridded electron gun injector,has a simple structure capable of generating numerous electron beams.However,its emittance is typically high.In this study,methods to reduce beam emittance are explored through a comprehensive analysis of various grid structures and preliminary design results,examining the evolution of beam phase space at different grid positions.An optimization method for reducing the emittance of a gridded thermionic-cathode electron gun is proposed through theoretical derivation,electromagnetic-field simulation,and beam-dynamics simulation.A 50%reduction in emittance was achieved for a 50 keV,1.7 A electron gun,laying the foundation for the subsequent design of a high-current,low-emittance injector.
基金financially supported by the National Nat-ural Science Foundation of China(No.52404337)the Chun-hui Plan Collaborative Research Project from Chinese Edu-cation Ministry(No.HZKY20220036)+1 种基金the Guangdong Ba-sic and Applied Basic Research Foundation,China(No.2022A1515110062)the Young Elite Scientists Spon-sorship Program by China Association for Science and Tech-nology(No.YESS20220231).
文摘SiO_(2)–CaO–Al_(2)O_(3)ternary inclusions are among the most common complex oxide inclusions in steel.Nevertheless,the chemical and physical properties of these composite inclusions,particularly with detailed composition changes,have not been sufficiently investigated.In this study,first-principles density functional theory calculations were used to determine the electronic,mechanical,and thermodynamic properties of two stable phases in the SiO_(2)–CaO–Al_(2)O_(3)ternary inclusion system:anorthite(CaAl_(2)Si_(2)O_(8))and gehlenite(Ca_(2)Al_(2)SiO_(7)).Based on the electronic density of states analysis and band structure calculations,oxygen atoms play important roles in the electron reactivity of both phases.Young’s modulus and Poisson’s ratios were calculated and compared with those of the SiO_(2)–CaO inclusions.The Young’s moduli of CaAl_(2)Si_(2)O_(8)(101.32 GPa)and Ca_(2)Al_(2)SiO_(7)(131.43 GPa)were close to the maximum and minimum Young’s moduli of the binary oxide inclusions,respectively.With increasing temperature,the Young’s moduli of CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)showed slight increasing and decreasing trends,respectively,whereas the Poisson’s ratio decreased.Furthermore,the thermodynamic properties,particularly temperature-related thermal expansion coefficients,were also deeply investigated.The thermal expansion coefficients of both CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)increased rapidly with increasing temperature in the low-temperature regime above 300K.As the temperature increased,the increasing trend slowed.When the temperature reached 2000 K,the thermal expansion coefficients of CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)respectively were 12×10^(−6)and 8.5×10^(−6)K^(−1).These findings enhance the understanding of the physical nature of ternary inclusions in steels and provide a scientific foundation for analyzing their effects on steel performance using a more comprehensive inclusion database,thereby contributing to inclusion engineering in the development of materials with superior mechanical integrity.
基金supported by the introduction of Talent Research Fund in Nanjing Institute of Technology(YKJ202204)the National Natural Science Foundation of China(52401282 and 52300206)the Natural Science Foundation of Jiangsu Province(BK20230701 and BK20230705).
文摘Achieving high-energy density remains a key objective for advanced energy storage systems.However,challenges,such as poor cathode conductivity,anode dendrite formation,polysulfide shuttling,and electrolyte degradation,continue to limit performance and stability.Molecular and ionic dipole interactions have emerged as an effective strategy to address these issues by regulating ionic transport,modulating solvation structures,optimizing interfacial chemistry,and enhancing charge transfer kinetics.These interactions also stabilize electrode interfaces,suppress side reactions,and mitigate anode corrosion,collectively improving the durability of high-energy batteries.A deeper understanding of these mechanisms is essential to guide the design of next-generation battery materials.Herein,this review summarizes the development,classification,and advantages of dipole interactions in high-energy batteries.The roles of dipoles,including facilitating ion transport,controlling solvation dynamics,stabilizing the electric double layer,optimizing solid electrolyte interphase and cathode–electrolyte interface layers,and inhibiting parasitic reactions—are comprehensively discussed.Finally,perspectives on future research directions are proposed to advance dipole-enabled strategies for high-performance energy storage.This review aims to provide insights into the rational design of dipole-interactive systems and promote the progress of electrochemical energy storage technologies.
