Flexible bending strain sensors emerge as promising candidates for wearable health monitoring and human-machine interaction, owing to their high stability and sensitivity. However, a critical trade-off between high se...Flexible bending strain sensors emerge as promising candidates for wearable health monitoring and human-machine interaction, owing to their high stability and sensitivity. However, a critical trade-off between high sensitivity and reliable largeangle sensing capability persists as a key bottleneck, severely hindering their practical implementation. In this study, a synergistic material-structural engineering strategy is proposed to enhance the bend-sensing performance. Specifically, two core components of this strategy involve an in-house synthesized carbon-based conductive particulate ink with favorable printability and a rationally designed sensing layer structure. By integrating the two components via electrohydrodynamic printing technology, we successfully fabricated highly robust flexible bending strain sensors. The resulting sensors exhibit exceptional electromechanical responsiveness to bending deformation, including a wide operating range(10°–150°), high sensitivity(GF = 50.74), rapid response, low hysteresis, and excellent long-term stability. Practically, they can accurately capture diverse physiological signals, ranging from subtle carotid artery pulses to large elbow flexion. Furthermore, a wearable gesture recognition system, incorporating a printed flexible bending strain sensor array, was developed to enable precise gesture recognition, thereby realizing virtual flight control of an unmanned aerial vehicle. These results indicate that the proposed printed sensor provides a promising approach to the sensitivity-angle trade-off, thereby facilitating the practical implementation of flexible electronics in human-machine interaction.展开更多
Super-fine electrohydrodynamic inkjet(SIJ)printing of perovskite nanocrystal(PNC)colloid ink exhibits significant potential in the fabrication of high-resolution color conversion microstructures arrays for fullcolor m...Super-fine electrohydrodynamic inkjet(SIJ)printing of perovskite nanocrystal(PNC)colloid ink exhibits significant potential in the fabrication of high-resolution color conversion microstructures arrays for fullcolor micro-LED displays.However,the impact of solvent on both the printing process and the morphology of SIJ-printed PNC color conversion microstructures remains underexplored.In this study,we prepared samples of CsPbBr3PNC colloid inks in various solvents and investigated the solvent's impact on SIJ printed PNC microstructures.Our findings reveal that the boiling point of the solvent is crucial to the SIJ printing process of PNC colloid inks.Only does the boiling point of the solvent fall in the optimal range,the regular positioned,micron-scaled,conical PNC microstructures can be successfully printed.Below this optimal range,the ink is unable to be ejected from the nozzle;while above this range,irregular positioned microstructures with nanoscale height and coffee-ring-like morphology are produced.Based on these observations,high-resolution color conversion PNC microstructures were effectively prepared using SIJ printing of PNC colloid ink dispersed in dimethylbenzene solvent.展开更多
Cation segregation on cathode surfaces plays a key role in determining the activity and operational stability of solid oxide fuel cells(SOFCs).The double perovskite oxide PrBa_(0.8)Ca_(0.2)Co_(2)O_(5+δ)(PBCC)has been...Cation segregation on cathode surfaces plays a key role in determining the activity and operational stability of solid oxide fuel cells(SOFCs).The double perovskite oxide PrBa_(0.8)Ca_(0.2)Co_(2)O_(5+δ)(PBCC)has been widely studied as an active cathode but still suffer from serious detrimental segregations.To enhance the cathode stability,a PBCC derived A-site medium-entropy Pr_(0.6)La_(0.1)Nd_(0.1)Sm_(0.1)Gd_(0.1)Ba_(0.8)Ca_(0.2)Co_(2)O_(5+δ)(ME-PBCC)oxide was prepared and its segregation behaviors were investigated under different conditions.Compared with initial PBCC oxide,the segregations of BaO and Co_(3)O_(4)on the surface of ME-PBCC material are significantly suppressed,especially for Co_(3)O_(4),which is attributed to its higher configuration entropy.Our results also confirm the improved electrochemical performance and structural stability of ME-PBCC material,enabling it as a promising cathode for SOFCs.展开更多
This study focuses on the teaching reform of the communication application development course based on the core requirements of engineering education accreditation.To address key challenges such as the disconnection b...This study focuses on the teaching reform of the communication application development course based on the core requirements of engineering education accreditation.To address key challenges such as the disconnection between software and hardware teaching and insufficient practical skills among students,a project-driven“learning-practiceapplication”teaching model is proposed.By optimizing course content,innovating teaching methods,and introducing university-industry collaboration mechanisms,the reform aligns the curriculum more closely with engineering education standards and industry demands.The approach significantly enhances students’comprehensive skills,practical abilities,and employability.This study provides theoretical foundations and practical strategies for the teaching reform of courses in communication engineering.展开更多
Traffic datasets exhibit complex spatiotemporal characteristics,including significant fluctuations in traffic volume and intricate periodical patterns,which pose substantial challenges for the accurate forecasting and...Traffic datasets exhibit complex spatiotemporal characteristics,including significant fluctuations in traffic volume and intricate periodical patterns,which pose substantial challenges for the accurate forecasting and effective management of traffic conditions.Traditional forecasting models often struggle to adequately capture these complexities,leading to suboptimal predictive performance.While neural networks excel at modeling intricate and nonlinear data structures,they are also highly susceptible to overfitting,resulting in inefficient use of computational resources and decreased model generalization.This paper introduces a novel heuristic feature extraction method that synergistically combines the strengths of non-neural network algorithms with neural networks to enhance the identification and representation of relevant features from traffic data.We begin by evaluating the significance of various temporal characteristics using three distinct assessment strategies grounded in non-neural methodologies.These evaluated features are then aggregated through a weighted fusion mechanism to create heuristic features,which are subsequently integrated into neural network models for more accurate and robust traffic prediction.Experimental results derived from four real-world datasets,collected from diverse urban environments,show that the proposed method significantly improves the accuracy of long-term traffic forecasting without compromising performance.Additionally,the approach helps streamline neural network architectures,leading to a considerable reduction in computational overhead.By addressing both prediction accuracy and computational efficiency,this study not only presents an innovative and effective method for traffic condition forecasting but also offers valuable insights that can inform the future development of data-driven traffic management systems and transportation strategies.展开更多
Higher education is at the top of the educational hierarchy.With the booming development of the economy and society in China,its scale is also expanding greatly.Professional course teaching is a key component of highe...Higher education is at the top of the educational hierarchy.With the booming development of the economy and society in China,its scale is also expanding greatly.Professional course teaching is a key component of higher education,and it plays a vital role in cultivating professionalism and even the overall level of students.According to several problems existing in the current teaching practice of professional courses at our universities,in order to improve the teaching quality to meet the requirements in the emerging engineering era,related strategies and approaches for teaching reform are proposed as follows.Firstly,we advance the traditional classroom teaching into the modern one with equal double-subjects of teachers and students to cultivate the active and comprehensive learning ability of students.Secondly,the scientific research practice-oriented teaching method is introduced,and it contributes to connecting theory with engineering practice for students.Thirdly,the diversified course assessment system is explored,and a closed-loop quality control strategy is discussed on the basis of a questionnaire survey and face-to-face interview.By questionnaires and final assessments,it is clear that teaching qualities of related professional courses are satisfactory in recent years,and the methods and strategies can be widely applied to the teaching practice of other courses.展开更多
Ultra-thin crystalline silicon stands as a cornerstone material in the foundation of modern micro and nano electronics.Despite the proliferation of various materials including oxide-based,polymer-based,carbon-based,an...Ultra-thin crystalline silicon stands as a cornerstone material in the foundation of modern micro and nano electronics.Despite the proliferation of various materials including oxide-based,polymer-based,carbon-based,and two-dimensional(2D)materials,crystal silicon continues to maintain its stronghold,owing to its superior functionality,scalability,stability,reliability,and uniformity.Nonetheless,the inherent rigidity of the bulk silicon leads to incompatibility with soft tissues,hindering the utilization amid biomedical applications.Because of such issues,decades of research have enabled successful utilization of various techniques to precisely control the thickness and morphology of silicon layers at the scale of several nanometres.This review provides a comprehensive exploration on the features of ultra-thin single crystalline silicon as a semiconducting material,and its role especially among the frontier of advanced bioelectronics.Key processes that enable the transition of rigid silicon to flexible form factors are exhibited,in accordance with their chronological sequence.The inspected stages span both prior and subsequent to transferring the silicon membrane,categorized respectively as on-wafer manufacturing and rigid-to-soft integration.Extensive guidelines to unlock the full potential of flexible electronics are provided through ordered analysis of each manufacturing procedure,the latest findings of biomedical applications,along with practical perspectives for researchers and manufacturers.展开更多
The Cooling Storage Ring of the Heavy Ion Research Facility in Lanzhou(HIRFL-CSR)was constructed to study nuclear physics,atomic physics,interdisciplinary science,and related applications.The External Target Facility(...The Cooling Storage Ring of the Heavy Ion Research Facility in Lanzhou(HIRFL-CSR)was constructed to study nuclear physics,atomic physics,interdisciplinary science,and related applications.The External Target Facility(ETF)is located in the main ring of the HIRFL-CSR.The gamma detector of the ETF is built to measure emitted gamma rays with energies below 5 MeV in the center-of-mass frame and is planned to measure light fragments with energies up to 300 MeV.The readout electronics for the gamma detector were designed and commissioned.The readout electronics consist of thirty-two front-end cards,thirty-two readout control units(RCUs),one common readout unit,one synchronization&clock unit,and one sub-trigger unit.By using the real-time peak-detection algorithm implemented in the RCU,the data volume can be significantly reduced.In addition,trigger logic selection algorithms are implemented to improve the selection of useful events and reduce the data size.The test results show that the integral nonlinearity of the readout electronics is less than 1%,and the energy resolution for measuring the 60 Co source is better than 5.5%.This study discusses the design and performance of the readout electronics.展开更多
The Cooling Storage Ring(CSR)external-target experiment(CEE)will be the first large-scale nuclear physics experiment at the Heavy Ion Research Facility in Lanzhou(HIRFL).A beam monitor has been developed to monitor th...The Cooling Storage Ring(CSR)external-target experiment(CEE)will be the first large-scale nuclear physics experiment at the Heavy Ion Research Facility in Lanzhou(HIRFL).A beam monitor has been developed to monitor the beam status and to improve the reconstruction resolution of the primary vertex.Custom-designed pixel charge sensors,named TopmetalCEEv1,are employed in the detector to locate the position of each particle.Readout electronics for the beam monitor were designed,including front-end electronics utilizing the Topmetal-CEEv1 sensors,as well as a readout and control unit that communicates with the DAQ,trigger,and clock systems.A series of tests were performed to validate the functionality and performance of the system,including basic electronic verifications and responses toαparticles and heavy-ion beams.The results show that all designed functions of the readout electronics system work well,and this system could be used for beam monitoring in the CEE experiment.展开更多
The presence of a van Hove singularity(vHS)at the Fermi level can trigger magnetic instability by mediating a spontaneous transition from paramagnetic to magnetically ordered states.While electrostatic doping(typicall...The presence of a van Hove singularity(vHS)at the Fermi level can trigger magnetic instability by mediating a spontaneous transition from paramagnetic to magnetically ordered states.While electrostatic doping(typically achieved via ionic gating)to shift the vHS to the Fermi level provides a general mechanism for engineering such magnetism,its volatile nature often leads to the collapse of induced states upon gate field removal.Here,a novel scheme is presented for non-volatile magnetic control by utilizing ferroelectric heterostructures to achieve reversible magnetism switching.Using two-dimensional VSiN_(3),a nonmagnetic material with Mexican-hat electronic band dispersions hosting vHSs,as a prototype,it is preliminarily demonstrated that both electron and hole doping can robustly induce magnetism.Further,by interfacing VSiN_(3)with ferroelectric Sc_(2)CO_(2),reversible switching of its magnetic state via polarization-driven heterointerfacial charge transfer is achieved.This mechanism enables a dynamic transition between insulating and half-metallic phases in VSiN_(3),establishing a pathway to design multiferroic tunnel junctions with giant tunneling electroresistance or magnetoresistance.This work bridges non-volatile ferroelectric control with vHS-enhanced magnetism,opening opportunities for energy-efficient and high-performance spintronic devices and non-volatile memory devices.展开更多
In many practical structures, physical parameters of material and applied loads have random property.To optimize this kind of structures,an optimum mathematical model was built.This model has reliability constraints o...In many practical structures, physical parameters of material and applied loads have random property.To optimize this kind of structures,an optimum mathematical model was built.This model has reliability constraints on dynamic stress and displacement and upper & lower limits of the design variables. The numerical characteristic of dynamic response and sensitivity of dynamic response based on probability of structure were deduced respectively. By equivalent disposing, the reliability constraints were changed into conventional forms. The SUMT method was used in the optimization process.Two examples illustrate the correctness and practicability of the optimum model and solving approach.展开更多
In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar perce...In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar percentage of Na_(2)Ni_(2)Ti_(6)O_(16)(NNTO)within Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)(NMTO),with x values of 10,20,30,40,and 50.Both XPS(X-ray Photoelectron Spectroscopy)and EDX(Energy Dispersive X-ray Spectroscopy)analyses unequivocally validated the formation of the NNMTO-x solid solutions.It was observed that when x is below 40,the NNMTO-x solid solution retains the structural characteristics of the original NMTO.However,beyond this threshold,significant alterations in crystal morphology were noted,accompanied by a noticeable decline in photocatalytic activity.Notably,the absorption edge of NNMTO-x(x<40)exhibited a shift towards the visible-light spectrum,thereby substantially broadening the absorption range.The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO_(2).Specifically,after a 6 h irradiation period,the production rates of CO and CH_(4)were recorded at 42.38 and 1.47μmol/g,respectively.This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO_(2)reduction processes.展开更多
[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau...[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau damping,which is particularly important for storage rings operating with ultra-low emittance or atlow beam energy.[Purpose]To further increase the bunch length without additional hardware costs,the phasemodulation in a dual-RF system is considered.[Methods]In this paper,turn-by-turn simulations incorporating randomsynchrotron radiation excitation are conducted,and a brief analysis is presented to explain the bunch lengtheningmechanism.[Results]Simulation results reveal that the peak current can be further reduced,thereby mitigating IBSeffects and enhancing the Touschek lifetime.Although the energy spread increases,which tends to reduce thebrightness of higher-harmonic radiation from the undulator,the brightness of the fundamental harmonic can,in fact,beimproved.展开更多
The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF...The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.展开更多
The poor electrical conductivity of metal-organic frameworks(MOFs)limits their electrocatalytic performance in the oxygen evolution reaction(OER).In this study,a Py@Co-MOF composite material based on pyrene(Py)molecul...The poor electrical conductivity of metal-organic frameworks(MOFs)limits their electrocatalytic performance in the oxygen evolution reaction(OER).In this study,a Py@Co-MOF composite material based on pyrene(Py)molecules and{[Co2(BINDI)(DMA)_(2)]·DMA}_(n)(Co-MOF,H4BINDI=N,N'-bis(5-isophthalic acid)naphthalenediimide,DMA=N,N-dimethylacetamide)was synthesized via a one-pot method,leveragingπ-πinteractions between pyrene and Co-MOF to modulate electrical conductivity.Results demonstrate that the Py@Co-MOF catalyst exhibited significantly enhanced OER performance compared to pure Co-MOF or pyrene-based electrodes,achieving an overpotential of 246 mV at a current density of 10 mA·cm^(-2) along with excellent stability.Density functional theory(DFT)calculations reveal that the formation of O*in the second step is the rate-determining step(RDS)during the OER process on Co-MOF,with an energy barrier of 0.85 eV due to the weak adsorption affinity of the OH*intermediate for Co sites.CCDC:2419276.展开更多
Inspections of power transmission lines(PTLs)conducted using unmanned aerial vehicles(UAVs)are complicated by the fine structure of the lines and complex backgrounds,making accurate and efficient segmentation challeng...Inspections of power transmission lines(PTLs)conducted using unmanned aerial vehicles(UAVs)are complicated by the fine structure of the lines and complex backgrounds,making accurate and efficient segmentation challenging.This study presents the Wavelet-Guided Transformer U-Net(WGT-UNet)model,a new hybrid net-work that combines Convolutional Neural Networks(CNNs),Discrete Wavelet Transform(DWT),and Transformer architectures.The model’s primary contribution is based on spatial and channel attention mechanisms derived from wavelet subbands to guide the Transformer’s self-attention structure.Thus,low and high frequency components are separated at each stage using DWT,suppressing structural noise and making linear objects more prominent.The developed design is supported by multi-component hybrid cost functions that simultaneously solve class imbalance,edge sharpness,structural integrity,and spatial regularity issues.Furthermore,high segmentation success has been achieved in producing sharp boundaries and continuous line structures with the DWT-guided attention mechanism.Experiments conducted on the TTPLA dataset reveal that the version using the ConvNeXt backbone outperforms the current state-of-the-art approaches with an F1-Score of 79.33%and an Intersection over Union(IoU)value of 68.38%.The models and visual outputs of the developed method and all compared models can be accessed at https://github.com/burhanbarakli/WGT-UNET.展开更多
β-Ga_(2)O_(3)is a promising candidate for solarblind ultraviolet photodetection owing to its suitable bandgap of approximately 4.9 eV,excellent photoresponse characteristics,and high stability.However,the lack of a s...β-Ga_(2)O_(3)is a promising candidate for solarblind ultraviolet photodetection owing to its suitable bandgap of approximately 4.9 eV,excellent photoresponse characteristics,and high stability.However,the lack of a sufficient driving force within the material leads to extensive bulk charge recombination,limiting its photocurrent and thus posing significant challenges in designing high-performance Ga_(2)O_(3)-based photodetection.In this study,we propose a gradient doping strategy to achieve a Sn-doping concentration gradient along theβ-Ga_(2)O_(3)film thickness.By combining sol-gel synthesis with rapid thermal annealing,a spatially graded band structure with a full-space built-in electric field is constructed,which increases the width of band bending over a large region and is crucial for significantly enhancing carrier separation and transport in the bulk.The resulting gradient Sn-dopedβ-Ga_(2)O_(3)enables exceptional photoelectric performance without an external bias under 254 nm irradiation,including a superior responsivity of 66.88 mA W^(-1),a high detectivity of 8.12×10^(11)Jones,and a fast rise/decay time of 79/65 ms,outstanding most existing similar reported photoelectrochemical(PEC)type optoelectronic devices.Additionally,the device exhibits excellent long-term stability and enables high-resolution underwater ultraviolet imaging.This study demonstrates that the gradient doping strategy provides a feasible approach for enhancing the PEC performance ofβ-Ga_(2)O_(3)photoelectrodes.展开更多
ThePigeon-InspiredOptimization(PIO)algorithmconstitutes ametaheuristic method derived fromthe homing behaviour of pigeons.Initially formulated for three-dimensional path planning in unmanned aerial vehicles(UAVs),the ...ThePigeon-InspiredOptimization(PIO)algorithmconstitutes ametaheuristic method derived fromthe homing behaviour of pigeons.Initially formulated for three-dimensional path planning in unmanned aerial vehicles(UAVs),the algorithmhas attracted considerable academic and industrial interest owing to its effective balance between exploration and exploitation,coupled with advantages in real-time performance and robustness.Nevertheless,as applications have diversified,limitations in convergence precision and a tendency toward premature convergence have become increasingly evident,highlighting a need for improvement.This reviewsystematically outlines the developmental trajectory of the PIO algorithm,with a particular focus on its core applications in UAV navigation,multi-objective formulations,and a spectrum of variantmodels that have emerged in recent years.It offers a structured analysis of the foundational principles underlying the PIO.It conducts a comparative assessment of various performance-enhanced versions,including hybrid models that integrate mechanisms from other optimization paradigms.Additionally,the strengths andweaknesses of distinct PIOvariants are critically examined frommultiple perspectives,including intrinsic algorithmic characteristics,suitability for specific application scenarios,objective function design,and the rigor of the statistical evaluation methodologies employed in empirical studies.Finally,this paper identifies principal challenges within current PIO research and proposes several prospective research directions.Future work should focus on mitigating premature convergence by refining the two-phase search structure and adjusting the exponential decrease of individual numbers during the landmark operator.Enhancing parameter adaptation strategies,potentially using reinforcement learning for dynamic tuning,and advancing theoretical analyses on convergence and complexity are also critical.Further applications should be explored in constrained path planning,Neural Architecture Search(NAS),and other real-worldmulti-objective problems.For Multi-objective PIO(MPIO),key improvements include controlling the growth of the external archive and designing more effective selection mechanisms to maintain convergence efficiency.These efforts are expected to strengthen both the theoretical foundation and practical versatility of PIO and its variants.展开更多
To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.T...To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.展开更多
X-rays are widely used in the non-destructive testing(NDT)of electrical equipment.Radio frequency(RF)electron linear accelerators can generate MeV high-energy X-rays with strong penetrating ability;however,the system ...X-rays are widely used in the non-destructive testing(NDT)of electrical equipment.Radio frequency(RF)electron linear accelerators can generate MeV high-energy X-rays with strong penetrating ability;however,the system generally has a large scale,which is not suitable for on-site testing.Compared with the S-band(S-linac)at the same stage of beam energy,the accelerator working in the X-band(X-linac)can compress the facility scale by over 2/3 in the longitudinal direction,which is convenient for the on-site NDT of electrical equipment.To address the beam quality and design complexity simultaneously,the non-dominated sorting genetic algorithmⅡ(NSGA-Ⅱ),which is a multi-objective genetic algorithm(MOGA),was developed to optimize the cavity chain design of the X-linac.Additionally,the designs of the focusing coils,electron gun,and RF couplers,which are other key components of the X-linac,were introduced in this context.In particular,the focusing coil distributions were optimized using a genetic algorithm.Furthermore,after designing such key components,PARMELA software was adopted to perform beam dynamics calculations with the optimized accelerating fields and magnetic fields.The results show that the beam performance was obtained with a capture ratio of more than 90%,an energy spread of less than 10%,and an average energy of approximately 3 MeV.The design and simulation results indicate that the proposed NSGAⅡ-based approach is feasible for X-linac accelerator design.Furthermore,it can be generalized as a universal technique for industrial electron linear accelerators provided that specific optimization objectives and constraints are set according to different application scenarios and requirements.展开更多
基金supported by the Guangdong University Featured Innovation Program Project (Grant No.2024KTSCX043)the Guangdong Basic and Applied Basic Research Foundation (Grant Nos.2025A1515010967,2022A1515110621)+1 种基金the Innovation and Strong School Engineering Fund of Guangdong Province (Grant No.2025KCXTD047)the Guangdong Engineering Technology Research Center (Grant No.2021J020)。
文摘Flexible bending strain sensors emerge as promising candidates for wearable health monitoring and human-machine interaction, owing to their high stability and sensitivity. However, a critical trade-off between high sensitivity and reliable largeangle sensing capability persists as a key bottleneck, severely hindering their practical implementation. In this study, a synergistic material-structural engineering strategy is proposed to enhance the bend-sensing performance. Specifically, two core components of this strategy involve an in-house synthesized carbon-based conductive particulate ink with favorable printability and a rationally designed sensing layer structure. By integrating the two components via electrohydrodynamic printing technology, we successfully fabricated highly robust flexible bending strain sensors. The resulting sensors exhibit exceptional electromechanical responsiveness to bending deformation, including a wide operating range(10°–150°), high sensitivity(GF = 50.74), rapid response, low hysteresis, and excellent long-term stability. Practically, they can accurately capture diverse physiological signals, ranging from subtle carotid artery pulses to large elbow flexion. Furthermore, a wearable gesture recognition system, incorporating a printed flexible bending strain sensor array, was developed to enable precise gesture recognition, thereby realizing virtual flight control of an unmanned aerial vehicle. These results indicate that the proposed printed sensor provides a promising approach to the sensitivity-angle trade-off, thereby facilitating the practical implementation of flexible electronics in human-machine interaction.
基金supported by the National Natural Science Foundation of China(No.62374142)Fundamental Research Funds for the Central Universities(Nos.20720220085 and 20720240064)+2 种基金External Cooperation Program of Fujian(No.2022I0004)Major Science and Technology Project of Xiamen in China(No.3502Z20191015)Xiamen Natural Science Foundation Youth Project(No.3502Z202471002)。
文摘Super-fine electrohydrodynamic inkjet(SIJ)printing of perovskite nanocrystal(PNC)colloid ink exhibits significant potential in the fabrication of high-resolution color conversion microstructures arrays for fullcolor micro-LED displays.However,the impact of solvent on both the printing process and the morphology of SIJ-printed PNC color conversion microstructures remains underexplored.In this study,we prepared samples of CsPbBr3PNC colloid inks in various solvents and investigated the solvent's impact on SIJ printed PNC microstructures.Our findings reveal that the boiling point of the solvent is crucial to the SIJ printing process of PNC colloid inks.Only does the boiling point of the solvent fall in the optimal range,the regular positioned,micron-scaled,conical PNC microstructures can be successfully printed.Below this optimal range,the ink is unable to be ejected from the nozzle;while above this range,irregular positioned microstructures with nanoscale height and coffee-ring-like morphology are produced.Based on these observations,high-resolution color conversion PNC microstructures were effectively prepared using SIJ printing of PNC colloid ink dispersed in dimethylbenzene solvent.
基金Project supported by the National Natural Science Foundation of China(22279025,21773048,52302119)the Fundamental Research Funds for the Central Universities(2023FRFK06005,HIT.NSRIF202204)。
文摘Cation segregation on cathode surfaces plays a key role in determining the activity and operational stability of solid oxide fuel cells(SOFCs).The double perovskite oxide PrBa_(0.8)Ca_(0.2)Co_(2)O_(5+δ)(PBCC)has been widely studied as an active cathode but still suffer from serious detrimental segregations.To enhance the cathode stability,a PBCC derived A-site medium-entropy Pr_(0.6)La_(0.1)Nd_(0.1)Sm_(0.1)Gd_(0.1)Ba_(0.8)Ca_(0.2)Co_(2)O_(5+δ)(ME-PBCC)oxide was prepared and its segregation behaviors were investigated under different conditions.Compared with initial PBCC oxide,the segregations of BaO and Co_(3)O_(4)on the surface of ME-PBCC material are significantly suppressed,especially for Co_(3)O_(4),which is attributed to its higher configuration entropy.Our results also confirm the improved electrochemical performance and structural stability of ME-PBCC material,enabling it as a promising cathode for SOFCs.
基金Quality Engineering Project of Higher Education Institutions in Anhui Province(2023aqnujyxm26,2023sx060,2023zyxwjxalk124)Natural Science Key Research Project for Higher Education Institutions of Anhui Province(2024AH051117,2024AH051126)+1 种基金Excellent Young Backbone Teachers’Domestic and Foreign Visiting and Training Program in Universities(gxgnfx20220262022)Research and Industrialization Project of High Precision Positioning System for Intelligent Connected Vehicles。
文摘This study focuses on the teaching reform of the communication application development course based on the core requirements of engineering education accreditation.To address key challenges such as the disconnection between software and hardware teaching and insufficient practical skills among students,a project-driven“learning-practiceapplication”teaching model is proposed.By optimizing course content,innovating teaching methods,and introducing university-industry collaboration mechanisms,the reform aligns the curriculum more closely with engineering education standards and industry demands.The approach significantly enhances students’comprehensive skills,practical abilities,and employability.This study provides theoretical foundations and practical strategies for the teaching reform of courses in communication engineering.
基金supported by the Shandong Province Higher Education Young Innovative Talents Cultivation Programme Project:TJY2114Jinan City-School Integration Development Strategy Project:JNSX2023015the Natural Science Foundation of Shandong Province:ZR2021M F074.
文摘Traffic datasets exhibit complex spatiotemporal characteristics,including significant fluctuations in traffic volume and intricate periodical patterns,which pose substantial challenges for the accurate forecasting and effective management of traffic conditions.Traditional forecasting models often struggle to adequately capture these complexities,leading to suboptimal predictive performance.While neural networks excel at modeling intricate and nonlinear data structures,they are also highly susceptible to overfitting,resulting in inefficient use of computational resources and decreased model generalization.This paper introduces a novel heuristic feature extraction method that synergistically combines the strengths of non-neural network algorithms with neural networks to enhance the identification and representation of relevant features from traffic data.We begin by evaluating the significance of various temporal characteristics using three distinct assessment strategies grounded in non-neural methodologies.These evaluated features are then aggregated through a weighted fusion mechanism to create heuristic features,which are subsequently integrated into neural network models for more accurate and robust traffic prediction.Experimental results derived from four real-world datasets,collected from diverse urban environments,show that the proposed method significantly improves the accuracy of long-term traffic forecasting without compromising performance.Additionally,the approach helps streamline neural network architectures,leading to a considerable reduction in computational overhead.By addressing both prediction accuracy and computational efficiency,this study not only presents an innovative and effective method for traffic condition forecasting but also offers valuable insights that can inform the future development of data-driven traffic management systems and transportation strategies.
基金Undergraduate Education Reform Project of Dalian Maritime University(BJG-C2024072)Postgraduate Education Reform Project of Liaoning Province([2022]249-209)+1 种基金Education Reform Project of Dalian Minzu University(YB202547,YJS2024JG55,B2109)First-Class Undergraduate Courses of Liaoning Province([2022]302-1433,[2022]302-1452)。
文摘Higher education is at the top of the educational hierarchy.With the booming development of the economy and society in China,its scale is also expanding greatly.Professional course teaching is a key component of higher education,and it plays a vital role in cultivating professionalism and even the overall level of students.According to several problems existing in the current teaching practice of professional courses at our universities,in order to improve the teaching quality to meet the requirements in the emerging engineering era,related strategies and approaches for teaching reform are proposed as follows.Firstly,we advance the traditional classroom teaching into the modern one with equal double-subjects of teachers and students to cultivate the active and comprehensive learning ability of students.Secondly,the scientific research practice-oriented teaching method is introduced,and it contributes to connecting theory with engineering practice for students.Thirdly,the diversified course assessment system is explored,and a closed-loop quality control strategy is discussed on the basis of a questionnaire survey and face-to-face interview.By questionnaires and final assessments,it is clear that teaching qualities of related professional courses are satisfactory in recent years,and the methods and strategies can be widely applied to the teaching practice of other courses.
基金support received from National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIT)(RS-2024-00353768)the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIT)(RS-2025-02217919)+1 种基金funded by the Yonsei Fellowshipfunded by Lee Youn Jae and the KIST Institutional Program Project No.2E31603-22-140 (KJY).
文摘Ultra-thin crystalline silicon stands as a cornerstone material in the foundation of modern micro and nano electronics.Despite the proliferation of various materials including oxide-based,polymer-based,carbon-based,and two-dimensional(2D)materials,crystal silicon continues to maintain its stronghold,owing to its superior functionality,scalability,stability,reliability,and uniformity.Nonetheless,the inherent rigidity of the bulk silicon leads to incompatibility with soft tissues,hindering the utilization amid biomedical applications.Because of such issues,decades of research have enabled successful utilization of various techniques to precisely control the thickness and morphology of silicon layers at the scale of several nanometres.This review provides a comprehensive exploration on the features of ultra-thin single crystalline silicon as a semiconducting material,and its role especially among the frontier of advanced bioelectronics.Key processes that enable the transition of rigid silicon to flexible form factors are exhibited,in accordance with their chronological sequence.The inspected stages span both prior and subsequent to transferring the silicon membrane,categorized respectively as on-wafer manufacturing and rigid-to-soft integration.Extensive guidelines to unlock the full potential of flexible electronics are provided through ordered analysis of each manufacturing procedure,the latest findings of biomedical applications,along with practical perspectives for researchers and manufacturers.
基金supported by the National Natural Science Foundation of China (Nos. 12222512, 12375193, U2031206, U1831206, and U2032209)the Scientific Instrument Developing Project of the Chinese Academy of Sciences (GJJSTD20210009)+1 种基金the CAS Pioneer Hundred Talent Programthe CAS Light of West China Program
文摘The Cooling Storage Ring of the Heavy Ion Research Facility in Lanzhou(HIRFL-CSR)was constructed to study nuclear physics,atomic physics,interdisciplinary science,and related applications.The External Target Facility(ETF)is located in the main ring of the HIRFL-CSR.The gamma detector of the ETF is built to measure emitted gamma rays with energies below 5 MeV in the center-of-mass frame and is planned to measure light fragments with energies up to 300 MeV.The readout electronics for the gamma detector were designed and commissioned.The readout electronics consist of thirty-two front-end cards,thirty-two readout control units(RCUs),one common readout unit,one synchronization&clock unit,and one sub-trigger unit.By using the real-time peak-detection algorithm implemented in the RCU,the data volume can be significantly reduced.In addition,trigger logic selection algorithms are implemented to improve the selection of useful events and reduce the data size.The test results show that the integral nonlinearity of the readout electronics is less than 1%,and the energy resolution for measuring the 60 Co source is better than 5.5%.This study discusses the design and performance of the readout electronics.
基金supported by the National Natural Science Foundation of China(Nos.11927901,12105110,U2032209,12275105)the National Key Research and Development Program of China(Nos.2020YFE0202002,2022YFA1602103)the Fundamental Research Funds for the Central Universities(No.CCNU22QN005)。
文摘The Cooling Storage Ring(CSR)external-target experiment(CEE)will be the first large-scale nuclear physics experiment at the Heavy Ion Research Facility in Lanzhou(HIRFL).A beam monitor has been developed to monitor the beam status and to improve the reconstruction resolution of the primary vertex.Custom-designed pixel charge sensors,named TopmetalCEEv1,are employed in the detector to locate the position of each particle.Readout electronics for the beam monitor were designed,including front-end electronics utilizing the Topmetal-CEEv1 sensors,as well as a readout and control unit that communicates with the DAQ,trigger,and clock systems.A series of tests were performed to validate the functionality and performance of the system,including basic electronic verifications and responses toαparticles and heavy-ion beams.The results show that all designed functions of the readout electronics system work well,and this system could be used for beam monitoring in the CEE experiment.
基金supported by the National Natural Science Foundation of China(Grant Nos.62174016,12474047,12204202,and 11974355)the Basic Research Program of Jiangsu(Grant No.BK20220679)+1 种基金the Fund for Shanxi“1331Project”the Research Project Supported by Shanxi Scholarship Council of China.
文摘The presence of a van Hove singularity(vHS)at the Fermi level can trigger magnetic instability by mediating a spontaneous transition from paramagnetic to magnetically ordered states.While electrostatic doping(typically achieved via ionic gating)to shift the vHS to the Fermi level provides a general mechanism for engineering such magnetism,its volatile nature often leads to the collapse of induced states upon gate field removal.Here,a novel scheme is presented for non-volatile magnetic control by utilizing ferroelectric heterostructures to achieve reversible magnetism switching.Using two-dimensional VSiN_(3),a nonmagnetic material with Mexican-hat electronic band dispersions hosting vHSs,as a prototype,it is preliminarily demonstrated that both electron and hole doping can robustly induce magnetism.Further,by interfacing VSiN_(3)with ferroelectric Sc_(2)CO_(2),reversible switching of its magnetic state via polarization-driven heterointerfacial charge transfer is achieved.This mechanism enables a dynamic transition between insulating and half-metallic phases in VSiN_(3),establishing a pathway to design multiferroic tunnel junctions with giant tunneling electroresistance or magnetoresistance.This work bridges non-volatile ferroelectric control with vHS-enhanced magnetism,opening opportunities for energy-efficient and high-performance spintronic devices and non-volatile memory devices.
文摘In many practical structures, physical parameters of material and applied loads have random property.To optimize this kind of structures,an optimum mathematical model was built.This model has reliability constraints on dynamic stress and displacement and upper & lower limits of the design variables. The numerical characteristic of dynamic response and sensitivity of dynamic response based on probability of structure were deduced respectively. By equivalent disposing, the reliability constraints were changed into conventional forms. The SUMT method was used in the optimization process.Two examples illustrate the correctness and practicability of the optimum model and solving approach.
基金Supported by the Doctoral Research Start-up Project of Yuncheng University(YQ-2023067)Project of Shanxi Natural Science Foundation(202303021211189)+1 种基金Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Provinces(20220036)Shanxi ProvinceIntelligent Optoelectronic Sensing Application Technology Innovation Center and Shanxi Province Optoelectronic Information Science and TechnologyLaboratory,Yuncheng University.
文摘In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar percentage of Na_(2)Ni_(2)Ti_(6)O_(16)(NNTO)within Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)(NMTO),with x values of 10,20,30,40,and 50.Both XPS(X-ray Photoelectron Spectroscopy)and EDX(Energy Dispersive X-ray Spectroscopy)analyses unequivocally validated the formation of the NNMTO-x solid solutions.It was observed that when x is below 40,the NNMTO-x solid solution retains the structural characteristics of the original NMTO.However,beyond this threshold,significant alterations in crystal morphology were noted,accompanied by a noticeable decline in photocatalytic activity.Notably,the absorption edge of NNMTO-x(x<40)exhibited a shift towards the visible-light spectrum,thereby substantially broadening the absorption range.The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO_(2).Specifically,after a 6 h irradiation period,the production rates of CO and CH_(4)were recorded at 42.38 and 1.47μmol/g,respectively.This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO_(2)reduction processes.
基金National Natural Science Foundation of China(12405168)The Fundamental Research Funds for the Central Universities,China(2024CDJXY004)。
文摘[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau damping,which is particularly important for storage rings operating with ultra-low emittance or atlow beam energy.[Purpose]To further increase the bunch length without additional hardware costs,the phasemodulation in a dual-RF system is considered.[Methods]In this paper,turn-by-turn simulations incorporating randomsynchrotron radiation excitation are conducted,and a brief analysis is presented to explain the bunch lengtheningmechanism.[Results]Simulation results reveal that the peak current can be further reduced,thereby mitigating IBSeffects and enhancing the Touschek lifetime.Although the energy spread increases,which tends to reduce thebrightness of higher-harmonic radiation from the undulator,the brightness of the fundamental harmonic can,in fact,beimproved.
基金National Natural Science Foundation of China(11875039)Shanxi Scholarship Council of China(2023-033)+2 种基金Fundamental Research Program of Shanxi Province(202303021221071)China Baowu Low Carbon Metallurgical Innovation Foundation(2022)2023 Anhui Major Industrial Innovation Plan Project。
文摘The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.
文摘The poor electrical conductivity of metal-organic frameworks(MOFs)limits their electrocatalytic performance in the oxygen evolution reaction(OER).In this study,a Py@Co-MOF composite material based on pyrene(Py)molecules and{[Co2(BINDI)(DMA)_(2)]·DMA}_(n)(Co-MOF,H4BINDI=N,N'-bis(5-isophthalic acid)naphthalenediimide,DMA=N,N-dimethylacetamide)was synthesized via a one-pot method,leveragingπ-πinteractions between pyrene and Co-MOF to modulate electrical conductivity.Results demonstrate that the Py@Co-MOF catalyst exhibited significantly enhanced OER performance compared to pure Co-MOF or pyrene-based electrodes,achieving an overpotential of 246 mV at a current density of 10 mA·cm^(-2) along with excellent stability.Density functional theory(DFT)calculations reveal that the formation of O*in the second step is the rate-determining step(RDS)during the OER process on Co-MOF,with an energy barrier of 0.85 eV due to the weak adsorption affinity of the OH*intermediate for Co sites.CCDC:2419276.
文摘Inspections of power transmission lines(PTLs)conducted using unmanned aerial vehicles(UAVs)are complicated by the fine structure of the lines and complex backgrounds,making accurate and efficient segmentation challenging.This study presents the Wavelet-Guided Transformer U-Net(WGT-UNet)model,a new hybrid net-work that combines Convolutional Neural Networks(CNNs),Discrete Wavelet Transform(DWT),and Transformer architectures.The model’s primary contribution is based on spatial and channel attention mechanisms derived from wavelet subbands to guide the Transformer’s self-attention structure.Thus,low and high frequency components are separated at each stage using DWT,suppressing structural noise and making linear objects more prominent.The developed design is supported by multi-component hybrid cost functions that simultaneously solve class imbalance,edge sharpness,structural integrity,and spatial regularity issues.Furthermore,high segmentation success has been achieved in producing sharp boundaries and continuous line structures with the DWT-guided attention mechanism.Experiments conducted on the TTPLA dataset reveal that the version using the ConvNeXt backbone outperforms the current state-of-the-art approaches with an F1-Score of 79.33%and an Intersection over Union(IoU)value of 68.38%.The models and visual outputs of the developed method and all compared models can be accessed at https://github.com/burhanbarakli/WGT-UNET.
基金supported by the National Natural Science Foundation of China(12304102,62574029)Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0479)+1 种基金Science and Technology Research Project of Chongqing Education Committee(KJQN202400558)Doctoral Scientific Research Fund of Chongqing Normal University(23XLB029)。
文摘β-Ga_(2)O_(3)is a promising candidate for solarblind ultraviolet photodetection owing to its suitable bandgap of approximately 4.9 eV,excellent photoresponse characteristics,and high stability.However,the lack of a sufficient driving force within the material leads to extensive bulk charge recombination,limiting its photocurrent and thus posing significant challenges in designing high-performance Ga_(2)O_(3)-based photodetection.In this study,we propose a gradient doping strategy to achieve a Sn-doping concentration gradient along theβ-Ga_(2)O_(3)film thickness.By combining sol-gel synthesis with rapid thermal annealing,a spatially graded band structure with a full-space built-in electric field is constructed,which increases the width of band bending over a large region and is crucial for significantly enhancing carrier separation and transport in the bulk.The resulting gradient Sn-dopedβ-Ga_(2)O_(3)enables exceptional photoelectric performance without an external bias under 254 nm irradiation,including a superior responsivity of 66.88 mA W^(-1),a high detectivity of 8.12×10^(11)Jones,and a fast rise/decay time of 79/65 ms,outstanding most existing similar reported photoelectrochemical(PEC)type optoelectronic devices.Additionally,the device exhibits excellent long-term stability and enables high-resolution underwater ultraviolet imaging.This study demonstrates that the gradient doping strategy provides a feasible approach for enhancing the PEC performance ofβ-Ga_(2)O_(3)photoelectrodes.
基金supported by the National Natural Science Foundation of China under grant number 62066016the Natural Science Foundation of Hunan Province of China under grant number 2024JJ7395+2 种基金International and Regional Science and Technology Cooperation and Exchange Program of the Hunan Association for Science and Technology under grant number 025SKX-KJ-04Hunan Provincial Postgraduate Research Innovation Project under grant numberCX20251611Liye Qin Bamboo Slips Research Special Project of JishouUniversity 25LYY03.
文摘ThePigeon-InspiredOptimization(PIO)algorithmconstitutes ametaheuristic method derived fromthe homing behaviour of pigeons.Initially formulated for three-dimensional path planning in unmanned aerial vehicles(UAVs),the algorithmhas attracted considerable academic and industrial interest owing to its effective balance between exploration and exploitation,coupled with advantages in real-time performance and robustness.Nevertheless,as applications have diversified,limitations in convergence precision and a tendency toward premature convergence have become increasingly evident,highlighting a need for improvement.This reviewsystematically outlines the developmental trajectory of the PIO algorithm,with a particular focus on its core applications in UAV navigation,multi-objective formulations,and a spectrum of variantmodels that have emerged in recent years.It offers a structured analysis of the foundational principles underlying the PIO.It conducts a comparative assessment of various performance-enhanced versions,including hybrid models that integrate mechanisms from other optimization paradigms.Additionally,the strengths andweaknesses of distinct PIOvariants are critically examined frommultiple perspectives,including intrinsic algorithmic characteristics,suitability for specific application scenarios,objective function design,and the rigor of the statistical evaluation methodologies employed in empirical studies.Finally,this paper identifies principal challenges within current PIO research and proposes several prospective research directions.Future work should focus on mitigating premature convergence by refining the two-phase search structure and adjusting the exponential decrease of individual numbers during the landmark operator.Enhancing parameter adaptation strategies,potentially using reinforcement learning for dynamic tuning,and advancing theoretical analyses on convergence and complexity are also critical.Further applications should be explored in constrained path planning,Neural Architecture Search(NAS),and other real-worldmulti-objective problems.For Multi-objective PIO(MPIO),key improvements include controlling the growth of the external archive and designing more effective selection mechanisms to maintain convergence efficiency.These efforts are expected to strengthen both the theoretical foundation and practical versatility of PIO and its variants.
基金supported by the Quantum Science and Technology-National Science and Technology Major Project (Grant No.2024ZD0302502 for WZ)the National Natural Science Foundation of China(Grant No.92365210 for WZ)+1 种基金Tsinghua Initiative Scientific Research Program (for WZ)the project of Tsinghua University-Zhuhai Huafa Industrial Share Company Joint Institute for Architecture Optoelectronic Technologies (JIAOT,for YH)。
文摘To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.
基金supported by the National Natural Science Foundation of China(Nos.12341501 and 12575164)。
文摘X-rays are widely used in the non-destructive testing(NDT)of electrical equipment.Radio frequency(RF)electron linear accelerators can generate MeV high-energy X-rays with strong penetrating ability;however,the system generally has a large scale,which is not suitable for on-site testing.Compared with the S-band(S-linac)at the same stage of beam energy,the accelerator working in the X-band(X-linac)can compress the facility scale by over 2/3 in the longitudinal direction,which is convenient for the on-site NDT of electrical equipment.To address the beam quality and design complexity simultaneously,the non-dominated sorting genetic algorithmⅡ(NSGA-Ⅱ),which is a multi-objective genetic algorithm(MOGA),was developed to optimize the cavity chain design of the X-linac.Additionally,the designs of the focusing coils,electron gun,and RF couplers,which are other key components of the X-linac,were introduced in this context.In particular,the focusing coil distributions were optimized using a genetic algorithm.Furthermore,after designing such key components,PARMELA software was adopted to perform beam dynamics calculations with the optimized accelerating fields and magnetic fields.The results show that the beam performance was obtained with a capture ratio of more than 90%,an energy spread of less than 10%,and an average energy of approximately 3 MeV.The design and simulation results indicate that the proposed NSGAⅡ-based approach is feasible for X-linac accelerator design.Furthermore,it can be generalized as a universal technique for industrial electron linear accelerators provided that specific optimization objectives and constraints are set according to different application scenarios and requirements.
