A method is proposed to determine the temporal width of high-brightness radio-frequency compressed electron pulses based on cross-correlation technique involving electron bunches and laser-induced plasma. The temporal...A method is proposed to determine the temporal width of high-brightness radio-frequency compressed electron pulses based on cross-correlation technique involving electron bunches and laser-induced plasma. The temporal evolution of 2-dimensional transverse profile of ultrafast electron bunches repelled by the formed transient electric field of laser-induced plasma on a silver needle is investigated, and the pulse-width can be obtained by analyzing these time-dependent images.This approach can characterize radio-frequency compressed ultrafast electron bunches with picosecond or sub-picosecond timescale and up to 105 electron numbers.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
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 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 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
In this study,the dosimetric characteristics(thickness applicability,preheating time,temperature and humidity dependence,in-batch uniformity,readout reproducibility,dose linearity,self-decay,and electron energy respon...In this study,the dosimetric characteristics(thickness applicability,preheating time,temperature and humidity dependence,in-batch uniformity,readout reproducibility,dose linearity,self-decay,and electron energy response)of engineered polycarbonate films irradiated with an electron beam(0–600 kGy)were investigated using photoluminescence spectroscopy.The results show a linear relationship between photoluminescence intensity and radiation dose when the thickness of the polycarbonate film is 0.3 mm.A higher fluorescence intensity can be obtained by preheating at 60℃ for 180 min before photoluminescence spectrum analysis.As the temperature during spectral testing and the ambient humidity(during and after irradiation)increased,the photoluminescence intensity of the polycarbonate films decreased.The photoluminescence intensity deviation of the polycarbonate films produced within the same batch at 100 kGy is 2.73%.After ten times of repeated excitations and readouts,the coefficients of variation in photoluminescence intensity are less than 8.6%,and the linear correlation coefficient between photoluminescence intensity and irradiation dose is 0.965 in the dose capture range of 20–600 kGy.Within 60 days of irradiation,the photoluminescence intensity of the polycarbonate film decreased to 60%of the initial value.The response of the 0.3 mm polycarbonate films to electron beams with energies exceeding 3.5 MeV does not differ significantly.This comprehensive analysis indicates the potential of polycarbonate films as a high-radiation dose detection material.展开更多
We report a theoretical investigation into superconductivity within the MAXH_(6) quaternary hydride system using first-principles calculations,where M and A denote alkali and alkaline earth elements,respectively,and X...We report a theoretical investigation into superconductivity within the MAXH_(6) quaternary hydride system using first-principles calculations,where M and A denote alkali and alkaline earth elements,respectively,and X represents transition metal elements.Systematic analysis of electronic band structures,phonon dispersions,and electron-phonon coupling reveals that substitution of MA binary metal combinations and X metal atoms can create favorable conditions for superconductivity.Mapping of superconducting critical temperatures,combined with dynamical stability analysis through phonon calculations,identifies ten superconducting candidates at ambient pressure.Among these,LiNaAgH_(6) exhibits nearly-free-electron behavior reminiscent of monovalent electron superconductors.It demonstrates exceptional superconducting properties with electron–phonon coupling λ=2.707,which yields a superconducting transition temperature T_(c) of 206.4 K using the Allen–Dynes formula.Its structural analogs MgNaPdH_(6),LiMgPdH_(6),LiMgAgH_(6),LiMgAuH_(6) all exhibit superconducting transition temperatures above 110 K.These findings advance our fundamental understanding of superconductivity in quaternary hydrides and provide guidance for rational design of new high-temperature superconducting materials.展开更多
In this study,we meticulously designed a layered carbon-based catalytic material to induce the degradation of a series of organic pollutants by activating peroxymonosulfate(PMS) in the PMS-based advanced oxidation pro...In this study,we meticulously designed a layered carbon-based catalytic material to induce the degradation of a series of organic pollutants by activating peroxymonosulfate(PMS) in the PMS-based advanced oxidation processes(AOPs).Results indicated that the silicon and oxygen elements from the montmorillonite were incorporated into the catalyst matrix to form the Si-O-C structure.It was notable that the layered carbonaceous material with Si-O-C structure exhibited an outstanding catalytic effect on the synthesized layered catalytic material array,achieving over 90 % removal rate of most pollutants within 60 min.It was notable that the layered carbonaceous material with Si-O-C structure exhibited an outstanding catalytic effect on the synthesized layered catalytic material array.The salt bridge system confirmed that pollutants can provide electrons to the Si-O-C/PMS system,and we verified that the electron transfer process(ETP) mechanism was the main pathway for the degradation of pollutants in the Si-O-C/PMS system via the open-circuit potential analysis.In combination with the structural properties of different pollutants,we discovered that electron-donating pollutants can supply more electrons to the Si-O-C/PMS system,thereby enhancing the ETP process.The findings of this study are anticipated to advance the development and practical application of layered carbonaceous materials-based catalysts and support the design and implementation of nanoconfined catalysts in the field of AOPs.展开更多
Robotic electronic skin(e-skin)is inspired by human skin and endows robots with tactile perception,temperature detection,and environmental interaction capabilities.However,its development is hampered by prolonged desi...Robotic electronic skin(e-skin)is inspired by human skin and endows robots with tactile perception,temperature detection,and environmental interaction capabilities.However,its development is hampered by prolonged design cycles,limited signal enhancement,and weak cognitive abilities.Given that the convergence of artificial intelligence(AI)with e-skin is fundamentally transforming this landscape,the present review highlights the pivotal contributions of AI across the entire development spectrum of robotic e-skin,including design optimization,signal processing,and cognitive enhancement.AI-driven design paradigms dramatically shorten development time and enable the discovery of optimal sensor materials and structures.In signal processing,AI algorithms notably improve the ability to decouple complex sensory data,enabling robust,multimodal,super-resolution sensing.AI endows e-skin with advanced cognitive capabilities,allowing it to interpret intricate tactile information and intelligently respond to external environments.By underscoring the potential of AI throughout the entire development pipeline,this review aims to drive the creation of e-skin with minimal hardware and maximal cognition and thus achieve revolutionary breakthroughs in cutting-edge fields such as human-robot interactions,precise robot control,and soft robotics for environmental exploration.展开更多
Organometallics play a vital role in catalytic and synthetic processes.Understanding the indi-vidual elementary steps of the reactions of organo metallic com-pounds is crucial for the development and ratio-nal design ...Organometallics play a vital role in catalytic and synthetic processes.Understanding the indi-vidual elementary steps of the reactions of organo metallic com-pounds is crucial for the development and ratio-nal design of new organometallic reagents and catalysts.Study of gas-phase reactions is one of the key approaches to probing the individual elementary steps under isolated and re-producible conditions.A series of investigations have been reported on the gas-phase reac-tions between organometallic ions and neutral molecules under room temperature conditions.However,studies about the reactions between organometallic ions and neutral molecules un-der heating conditions are very limited.In this work,an apparatus with an electrospray ion-ization source and an ion funnel trap,which can be coupled with a high-temperature linear ion trap reactor,was designed and built.The apparatus can be used to investigate the reac-tions between organometallic ions and neutral molecules under heating conditions.By using the apparatus,the adsorption reactions of Rh(PPh_(3))_(2)^(+)+CO→Rh(PPh_(3))_(2)CO^(+)and CuPPh_(3)^(+)+CO_(2)→CuPPh_(3)CO_(2)+under variable temperature conditions have been conducted.The experiments showed that the reaction rate constant of Rh(PPh_(3))_(2)^(+)+CO increases first and then decreases with increasing temperature.In contrast,the rate constant of CuPPh_(3)^(+)+CO_(2)decreases monotonically as the temperature increases.Density functional theory calculations indicate that the adsorption reaction of Rh(PPh_(3))_(2)^(+)+CO→Rh(PPh_(3))_(2)CO^(+)is subject to a small barrier,while CuPPh_(3)^(+)+CO_(2)→CuPPh_(3)CO_(2)+is barri-erless,which is consistent with the experimentally observed temperature-dependent rate con-stants.The newly built apparatus can thus provide new kinetic information to address reac-tion mechanisms for organometallic ions.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11004060,11027403,and 11304224)the Shanghai Municipal Science and Technology Commission,China(Grant Nos.10XD1401800,09142200501,09ZR1409300,09JC1404700,and 10JC1404500)
文摘A method is proposed to determine the temporal width of high-brightness radio-frequency compressed electron pulses based on cross-correlation technique involving electron bunches and laser-induced plasma. The temporal evolution of 2-dimensional transverse profile of ultrafast electron bunches repelled by the formed transient electric field of laser-induced plasma on a silver needle is investigated, and the pulse-width can be obtained by analyzing these time-dependent images.This approach can characterize radio-frequency compressed ultrafast electron bunches with picosecond or sub-picosecond timescale and up to 105 electron numbers.
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 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.
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 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.
基金supported by the National Natural Science Foundation of China(No.12305385)Key Projects of Scientific Research of the Hunan Provincial Department of Education(22A0310)the Research Startup Project of University of South China(220XQD025).
文摘In this study,the dosimetric characteristics(thickness applicability,preheating time,temperature and humidity dependence,in-batch uniformity,readout reproducibility,dose linearity,self-decay,and electron energy response)of engineered polycarbonate films irradiated with an electron beam(0–600 kGy)were investigated using photoluminescence spectroscopy.The results show a linear relationship between photoluminescence intensity and radiation dose when the thickness of the polycarbonate film is 0.3 mm.A higher fluorescence intensity can be obtained by preheating at 60℃ for 180 min before photoluminescence spectrum analysis.As the temperature during spectral testing and the ambient humidity(during and after irradiation)increased,the photoluminescence intensity of the polycarbonate films decreased.The photoluminescence intensity deviation of the polycarbonate films produced within the same batch at 100 kGy is 2.73%.After ten times of repeated excitations and readouts,the coefficients of variation in photoluminescence intensity are less than 8.6%,and the linear correlation coefficient between photoluminescence intensity and irradiation dose is 0.965 in the dose capture range of 20–600 kGy.Within 60 days of irradiation,the photoluminescence intensity of the polycarbonate film decreased to 60%of the initial value.The response of the 0.3 mm polycarbonate films to electron beams with energies exceeding 3.5 MeV does not differ significantly.This comprehensive analysis indicates the potential of polycarbonate films as a high-radiation dose detection material.
基金supported by the National Key R&D Program of China (Grant No.2022YFA1403201)the National Natural Science Foundation of China (Grant Nos.12125404,T2495231,123B2049,and 12204138)+9 种基金the Advanced MaterialsNational Science and Technology Major Project (Grant No.2024ZD0607000)the Natural Science Foundation of Jiangsu Province (Grant Nos.BK20233001 and BK20253009)the Jiangsu Funding Program for Excellent Postdoctoral Talent (Grant No.2024ZB002)the China Postdoctoral Science Foundation (Grant No.2025M773331)the Fundamental and Interdisciplinary Disciplines Breakthrough Plan of the Ministry of Education of Chinathe AI&AI for Science program of Nanjing UniversityArtificial Intelligence and Quantum physics (AIQ) program of Nanjing Universitythe Fundamental Research Funds for the Central Universitiesthe Natural Science Foundation of Nanjing University of Posts and Telecommunications(Grant Nos.NY224165,NY220038,and NY219087)the Hua Li Talents Program of Nanjing University of Posts and Telecommunications。
文摘We report a theoretical investigation into superconductivity within the MAXH_(6) quaternary hydride system using first-principles calculations,where M and A denote alkali and alkaline earth elements,respectively,and X represents transition metal elements.Systematic analysis of electronic band structures,phonon dispersions,and electron-phonon coupling reveals that substitution of MA binary metal combinations and X metal atoms can create favorable conditions for superconductivity.Mapping of superconducting critical temperatures,combined with dynamical stability analysis through phonon calculations,identifies ten superconducting candidates at ambient pressure.Among these,LiNaAgH_(6) exhibits nearly-free-electron behavior reminiscent of monovalent electron superconductors.It demonstrates exceptional superconducting properties with electron–phonon coupling λ=2.707,which yields a superconducting transition temperature T_(c) of 206.4 K using the Allen–Dynes formula.Its structural analogs MgNaPdH_(6),LiMgPdH_(6),LiMgAgH_(6),LiMgAuH_(6) all exhibit superconducting transition temperatures above 110 K.These findings advance our fundamental understanding of superconductivity in quaternary hydrides and provide guidance for rational design of new high-temperature superconducting materials.
基金supported by National Natural Science Foundation of China (Nos.52170086,22476116,52074176)Natural Science Foundation of Shandong Province (Nos.ZR2021ME013,ZR2024ME156,ZR2022QB250)。
文摘In this study,we meticulously designed a layered carbon-based catalytic material to induce the degradation of a series of organic pollutants by activating peroxymonosulfate(PMS) in the PMS-based advanced oxidation processes(AOPs).Results indicated that the silicon and oxygen elements from the montmorillonite were incorporated into the catalyst matrix to form the Si-O-C structure.It was notable that the layered carbonaceous material with Si-O-C structure exhibited an outstanding catalytic effect on the synthesized layered catalytic material array,achieving over 90 % removal rate of most pollutants within 60 min.It was notable that the layered carbonaceous material with Si-O-C structure exhibited an outstanding catalytic effect on the synthesized layered catalytic material array.The salt bridge system confirmed that pollutants can provide electrons to the Si-O-C/PMS system,and we verified that the electron transfer process(ETP) mechanism was the main pathway for the degradation of pollutants in the Si-O-C/PMS system via the open-circuit potential analysis.In combination with the structural properties of different pollutants,we discovered that electron-donating pollutants can supply more electrons to the Si-O-C/PMS system,thereby enhancing the ETP process.The findings of this study are anticipated to advance the development and practical application of layered carbonaceous materials-based catalysts and support the design and implementation of nanoconfined catalysts in the field of AOPs.
基金supported by the National Natural Science Foundation of China(No.52375031)the Dongfang Electric Corporation-Zhejiang University Joint Innovation Research Institutethe Bellwethers Research and Development Plan of Zhejiang Province(No.2023C01045)。
文摘Robotic electronic skin(e-skin)is inspired by human skin and endows robots with tactile perception,temperature detection,and environmental interaction capabilities.However,its development is hampered by prolonged design cycles,limited signal enhancement,and weak cognitive abilities.Given that the convergence of artificial intelligence(AI)with e-skin is fundamentally transforming this landscape,the present review highlights the pivotal contributions of AI across the entire development spectrum of robotic e-skin,including design optimization,signal processing,and cognitive enhancement.AI-driven design paradigms dramatically shorten development time and enable the discovery of optimal sensor materials and structures.In signal processing,AI algorithms notably improve the ability to decouple complex sensory data,enabling robust,multimodal,super-resolution sensing.AI endows e-skin with advanced cognitive capabilities,allowing it to interpret intricate tactile information and intelligently respond to external environments.By underscoring the potential of AI throughout the entire development pipeline,this review aims to drive the creation of e-skin with minimal hardware and maximal cognition and thus achieve revolutionary breakthroughs in cutting-edge fields such as human-robot interactions,precise robot control,and soft robotics for environmental exploration.
基金supported by the National Natural Science Foundation of China(Nos.92461313 and 22121002)the National Key R&D Program of China(No.2021YFA1500704).
文摘Organometallics play a vital role in catalytic and synthetic processes.Understanding the indi-vidual elementary steps of the reactions of organo metallic com-pounds is crucial for the development and ratio-nal design of new organometallic reagents and catalysts.Study of gas-phase reactions is one of the key approaches to probing the individual elementary steps under isolated and re-producible conditions.A series of investigations have been reported on the gas-phase reac-tions between organometallic ions and neutral molecules under room temperature conditions.However,studies about the reactions between organometallic ions and neutral molecules un-der heating conditions are very limited.In this work,an apparatus with an electrospray ion-ization source and an ion funnel trap,which can be coupled with a high-temperature linear ion trap reactor,was designed and built.The apparatus can be used to investigate the reac-tions between organometallic ions and neutral molecules under heating conditions.By using the apparatus,the adsorption reactions of Rh(PPh_(3))_(2)^(+)+CO→Rh(PPh_(3))_(2)CO^(+)and CuPPh_(3)^(+)+CO_(2)→CuPPh_(3)CO_(2)+under variable temperature conditions have been conducted.The experiments showed that the reaction rate constant of Rh(PPh_(3))_(2)^(+)+CO increases first and then decreases with increasing temperature.In contrast,the rate constant of CuPPh_(3)^(+)+CO_(2)decreases monotonically as the temperature increases.Density functional theory calculations indicate that the adsorption reaction of Rh(PPh_(3))_(2)^(+)+CO→Rh(PPh_(3))_(2)CO^(+)is subject to a small barrier,while CuPPh_(3)^(+)+CO_(2)→CuPPh_(3)CO_(2)+is barri-erless,which is consistent with the experimentally observed temperature-dependent rate con-stants.The newly built apparatus can thus provide new kinetic information to address reac-tion mechanisms for organometallic ions.
