Accurate and efficient detection of building changes in remote sensing imagery is crucial for urban planning,disaster emergency response,and resource management.However,existing methods face challenges such as spectra...Accurate and efficient detection of building changes in remote sensing imagery is crucial for urban planning,disaster emergency response,and resource management.However,existing methods face challenges such as spectral similarity between buildings and backgrounds,sensor variations,and insufficient computational efficiency.To address these challenges,this paper proposes a novel Multi-scale Efficient Wavelet-based Change Detection Network(MewCDNet),which integrates the advantages of Convolutional Neural Networks and Transformers,balances computational costs,and achieves high-performance building change detection.The network employs EfficientNet-B4 as the backbone for hierarchical feature extraction,integrates multi-level feature maps through a multi-scale fusion strategy,and incorporates two key modules:Cross-temporal Difference Detection(CTDD)and Cross-scale Wavelet Refinement(CSWR).CTDD adopts a dual-branch architecture that combines pixel-wise differencing with semanticaware Euclidean distance weighting to enhance the distinction between true changes and background noise.CSWR integrates Haar-based Discrete Wavelet Transform with multi-head cross-attention mechanisms,enabling cross-scale feature fusion while significantly improving edge localization and suppressing spurious changes.Extensive experiments on four benchmark datasets demonstrate MewCDNet’s superiority over comparison methods:achieving F1 scores of 91.54%on LEVIR,93.70%on WHUCD,and 64.96%on S2Looking for building change detection.Furthermore,MewCDNet exhibits optimal performance on the multi-class⋅SYSU dataset(F1:82.71%),highlighting its exceptional generalization capability.展开更多
Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challe...Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challenges.In this work,we demonstrate for the firs time that the coherent radiation farfiel patterns from laser–foil interactions can serve as an in situ,real-time,and easy-to-implement diagnostic for an ultraintense laser focus.The laser-driven electron sheets,curved by the spatially varying laser fiel and leaving the targets at nearly the speed of light,produce doughnut-shaped patterns depending on the shapes of the focal spot and the absolute laser intensities.Assisted by particle-in-cell simulations,we can achieve measurements of the intensity and the focal spot,and provide immediate feedback to optimize the focal spots for extremely high intensity.展开更多
Ultra-intense electromagnetic fields exceeding 10^(23)W∕cm^(2)are enabling breakthroughs in compact laser-driven particle accelerators and revealing new quantum electrodynamics(QED)phenomena.However,conventional lase...Ultra-intense electromagnetic fields exceeding 10^(23)W∕cm^(2)are enabling breakthroughs in compact laser-driven particle accelerators and revealing new quantum electrodynamics(QED)phenomena.However,conventional laser-focusing methods face considerable engineering challenges and require substantial costs.Focusing schemes utilizing plasma optics can produce sub-micrometer focus spots beyond the diffraction limit and substantially enhance the peak intensity;however,owing to significant energy dissipation,they may fail to simultaneously increase the laser fluence.To address these challenges,we propose a focusing scheme employing a near-critical-density hollow plasma fiber(HPF)that utilizes graded refractive index dynamics to boost both laser peak intensity and fluence at the same time.Three-dimensional particle-in-cell simulations demonstrate the HPF’s capability to focus a 4.5-μm-diameter Gaussian beam to a sub-diffraction-limited 0.6-μm-diameter spot.The peak intensity and laser fluence can be enhanced by factors of 22 and 10,respectively,marking a substantial improvement over existing plasma-based focusing schemes.Furthermore,the proposed scheme exhibits wide-range parameter adaptation and high robustness,making it suitable for direct implementation in PW-class ultra-intense laser experiments.展开更多
Aligned SnS nanowires arrays were grown via a simple chemical vapor deposition method.As-synthesized SnS nanowires are single crystals grown along the[111]direction.The single SnS nanowire based device showed excellen...Aligned SnS nanowires arrays were grown via a simple chemical vapor deposition method.As-synthesized SnS nanowires are single crystals grown along the[111]direction.The single SnS nanowire based device showed excellent response to near infrared lights with good responsivity of 267.9 A/W,high external quantum efficiency of 3.12×10^4%and fast response time.Photodetectors were built on the aligned SnS nanowire arrays,exhibiting a light on/off ratio of 3.6,and the response and decay time of 4.5 and 0.7 s,respectively,to 1064 nm light illumination.展开更多
This paper presented a novel millimeterwave channel measurement platform for the 6G intelligent railway.This platform used phased array antenna with 64 elements and can support instant bandwidth up to 1 GHz.Combined w...This paper presented a novel millimeterwave channel measurement platform for the 6G intelligent railway.This platform used phased array antenna with 64 elements and can support instant bandwidth up to 1 GHz.Combined with improved multi-tone sounding signals,the platform can enhance dynamic measurement capability in high-speed railway scenarios.We performed calibration works about frequency flatness,frequency offset and proved platform reliability with channel emulator based closed-loop verification.We also carried out field trials in high-speed railway carriage scenarios.Based on measurement results,we extracted channel characteristic parameters of path loss,power delay profile and delay spread to further verify the field measurement performance of the platform.展开更多
Model I quasi-static nonlinear fracture of aluminum foams is analyzed by considering the effect of microscopic heterogeneity. Firstly, a continuum constitutive model is adopted to account for the plastic compressibili...Model I quasi-static nonlinear fracture of aluminum foams is analyzed by considering the effect of microscopic heterogeneity. Firstly, a continuum constitutive model is adopted to account for the plastic compressibility of the metallic foams. The yield strain modeled by a two- parameter Weibull-type function is adopted in the constitutive model. Then, a modified cohesive zone model is established to characterize the fracture behavior of aluminum foams with a cohesive zone ahead of the initial crack. The tensile traction versus local crack opening displacement relation is employed to describe the softening characteristics of the material. And a Weibull statistical model for peak bridging stress within the fracture process zone is used for considering microscopic heterogeneity of aluminum foams. Lastly, the influence of stochastic parameters on the curve of stress-strain is given. Numerical examples are given to illustrate the numerical model presented in this paper and the effects of Weibull parameters and material properties on J-integral are discussed.展开更多
Dynamic fracture behavior of a Griffith crack along the interface of an adhesive bonded material under normal loading is studied. The singular integral equations are obtained by employing integral transformation and i...Dynamic fracture behavior of a Griffith crack along the interface of an adhesive bonded material under normal loading is studied. The singular integral equations are obtained by employing integral transformation and introducing dislocation density functions. By adopting Gauss-Jacobi integration formula, the problem is reduced to the solution of algebraic equations, and by collocation dots method. their solutions can be obtained Based on the parametric discussions presented in the paper, the following conclusions can be drawn： （1） Mode I dynamic stress intensity factor （DSIF） increases with increasing initial crack length and decreasing visco-elastic layer thickness, revealing distinct size effect; （2） The influence of the visco-elastic adhesive relaxation time on the DSIF should not be ignored.展开更多
Work function plays a significant role in surface chemistry. Local work function provides the information of local d/pole-d/pole interaction and charge distribution between adsorbates and substrate, highlighting the l...Work function plays a significant role in surface chemistry. Local work function provides the information of local d/pole-d/pole interaction and charge distribution between adsorbates and substrate, highlighting the local charge effect of the targeted spot which is normally smeared out in conventional average work function measurements. Chloroaluminum phthalocyanine （CIA1Pc）, an important optoelectronic molecule with a permanent dipole moment pointing from the Pc ring to the ending CI atom, adsorbed on Au（111） in either Cl-up or Cl-down configuration. Scanning tunneling microscopy/spectroscopy measurements revealed that at the centers of Cl-up and CI-down molecules, the local work functions changed oppositely with respect to the Au（111） substrate. At their Pc lobes, however, the local work functions unanimously increased due to charging effect of the indole lobes in the CIAIPc molecule.展开更多
Large Language Models(LLMs)exhibit impressive performance across various Natural Language Processing(NLP)tasks due to their robust contextual understanding,content generation and few/zero-shot learning abilities.Howev...Large Language Models(LLMs)exhibit impressive performance across various Natural Language Processing(NLP)tasks due to their robust contextual understanding,content generation and few/zero-shot learning abilities.However,LLMs still show significant limitations while handling with mathematical problems that require complex reasoning skills and interpretable solving processes.Consequently,a series of research efforts have been made in solving mathematical problems using Large Language Models(SMP-LLM).This survey provides a comprehensive review of such endeavors.First,we introduce a two-layer classification system for SMP-LLM:at the primary layer,we categorize extant researches into four classes of solution methods,including:fine-tuning,prompt engineering,collaboration with symbolic solvers,and collaboration with evaluators/validators.At the second layer,we classify mathematical problems into four categories:math word problem,geometry problem,theorem proving,and combinatorial optimization problem.This classification system finds the correlation between solution methods and the categories of mathematical problems.Second,we analyzed typical research works under of each method,and summarized their strengths and weaknesses.Third,we elucidate current mainstream datasets for solving mathematical problems and analyzed how these datasets promote SMP-LLM research from different perspectives.Finally,summarize the challenges that SMP-LLM are facing and highlighted four research directions:geometric analysis,comprehension,and generation of mathematical expressions,indirect reasoning and benchmarks for evaluating mathematical ability.We hope that this survey can provide useful references for researchers interested in SMP-LLM.展开更多
Surface-enhanced Raman spectroscopy(SERS),as a great potential label-free tool in metabolite detection,offers a strategy for rapid bacterial identification.However,it still lacks experimentally supported spectral inte...Surface-enhanced Raman spectroscopy(SERS),as a great potential label-free tool in metabolite detection,offers a strategy for rapid bacterial identification.However,it still lacks experimentally supported spectral interpretation at the metabolite level for complex biosamples.We present a SERS-based method for reliable bacterial intracellular metabolic profiling using plasmonic colloids with high rapidness and costefficiency.A convolutional neural network model was constructed to accurately classify eight types of bacteria with an overall accuracy as high as 90.44%and identify the key spectral features for classification by Shapley Additive Explanations.Molecule-level interpretation of the SERS metabolic profiles has been further realized in combination with laser desorption/ionization mass spectrometry,evidencing the primary metabolite contribution to the bacterial spectral signatures and molecule-level distinctions among different bacterial types.We provide insights into the mechanism of bacterial identification by label-free SERS and pave the way for interpretable SERS diagnostic tools for various diseases.展开更多
As a computer vision task,object detection algorithms can be applied to various real-world sce-narios.However,efficient algorithms often come with a large number of parameters and high computational complexity.To meet...As a computer vision task,object detection algorithms can be applied to various real-world sce-narios.However,efficient algorithms often come with a large number of parameters and high computational complexity.To meet the demand for high-performance object detection algorithms on mobile devices and embedded devices with limited computational resources,we propose a new lightweight object detection algorithm called DLE-YOLO.Firstly,we design a novel backbone called dual-branch lightweight excitation network(DLEN)for feature extraction,which is mainly constructed by dual-branch lightweight excitation units(DLEU).DLEU is stacked with different numbers of dual-branch lightweight excitation blocks(DLEB),which can extract comprehensive features and integrate information between different channels of features.Secondly,in order to enhance the network to capture key feature information in the regions of interest,the attention model HS-coordinate attention(HS-CA)is introduced into the network.Thirdly,the localization loss utilizes SIoU loss to further optimize the accuracy of the bounding box.Our method achieves a mAP value of 46.0%on the MS-COCO dataset,which is a 2%mAP improvement compared to the baseline YOLOv5-m,while bringing a 19.3%reduction in parameter count and a 12.9%decrease in GFLOPs.Furthermore,our method outperforms some advanced lightweight object detection algorithms,validating the effectiveness of our approach.展开更多
Emergency communication in forested environments encounters extremely complex propagation conditions,whose channel characteristics cannot be accurately captured by conventional models designed for urban scenarios.This...Emergency communication in forested environments encounters extremely complex propagation conditions,whose channel characteristics cannot be accurately captured by conventional models designed for urban scenarios.This paper conducts field measurements and modeling for 380 MHz vehicle-to-infrastructure(V2I)links in the primeval forest of the Greater Khingan Mountains.Through joint analysis of large-scale and small-scale channel characteristics,we systematically reveal the signal attenuation,fading mechanisms,and delay spread behavior in such environments.Results indicate that for path loss modeling,the Alpha-Beta model outperforms the Close-In model in characterizing the rapid attenuation in dense foliage.Small-scale fading is predominantly Rayleigh-distributed,while Ricean fading only dominates in the initial stage,with its K-factor decreasing significantly as distance increases.The root mean square(RMS)delay spread ranges from 0 to 450 ns,follows a log-normal distribution,and is markedly larger than in urban scenarios.Based on these observations,a parametric tapped-delay-line(TDL)model is developed,effectively quantifying multipath delay,power decay,and fading characteristics.The proposed model can reproduce realistic propagation features in simulations,offering theoretical support for emergency communication system planning and optimization,as well as engineering guidance for enhancing communication reliability and coverage in disaster rescue scenarios.展开更多
Optical frequency division(OFD)produces low-noise microwave and millimeter-wave(mmWave)signals by transferring the exceptional stability of optical references to electronic frequency domains.Recent developments in int...Optical frequency division(OFD)produces low-noise microwave and millimeter-wave(mmWave)signals by transferring the exceptional stability of optical references to electronic frequency domains.Recent developments in integrated optical references and soliton microcombs have paved the way for miniaturizing OFD oscillators to chip scale.Critical to this realization is a rapid tunable frequency comb that is stabilized to the optical references,thereby coherently linking optical and electronic frequencies.In this work,we advance the on-chip OFD technology using an integrated high-speed lead zirconate titanate(PZT)stress-optic actuator on the SiN soliton microcomb resonator.The integrated PZT actuator tunes the resonance frequency of the soliton-generating microresonator with a bandwidth exceeding 10s MHz and thus adjusts the soliton repetition rate.Optical frequency division and low-noise mmWave generation are demonstrated by feedback control of the soliton repetition rate through the integrated PZT-actuator,and the soliton microcomb is stabilized to a pair of reference lasers that are locked to an integrated 4 m SiN coil reference cavity.Our approach provides a fast,versatile,and integrated control mechanism for OFD oscillators and their applications in advanced communications,sensing,and precise timing.展开更多
In perovskite solar cells(PSCs),chemical bath deposition(CBD)is promising as the core technique for preparing a commercial electron transport layer(ETL)because the film prepared by CBD exhibits excellent uniform and c...In perovskite solar cells(PSCs),chemical bath deposition(CBD)is promising as the core technique for preparing a commercial electron transport layer(ETL)because the film prepared by CBD exhibits excellent uniform and conformal coverage of the substrate.However,metal oxide(MO_(x))films prepared through CBD often have defects on the surface like oxygen vacancies and hydroxyl that limit the PSCs efficiency and degrade the long-term stability.展开更多
Obesity,one of the prevalent chronic diseases globally,is a serious threat to human health.Dietary natural compounds intervention is an effective means to alleviate obesity.The objective of this study was to investiga...Obesity,one of the prevalent chronic diseases globally,is a serious threat to human health.Dietary natural compounds intervention is an effective means to alleviate obesity.The objective of this study was to investigate the potential protective role of lotus seed protein(LSP)against obesity.The results of amino acid composition analysis indicated that LSP possessed a well-balanced distribution of amino acids and was rich in branched-chain amino acids(BCAAs).Meanwhile,LSP exhibited better ABTS radical scavenging,DPPH radical scavenging,hydroxyl radical scavenging,and Fe^(2+)chelating ability in vitro.In vivo,LSP intervention remarkably alleviated body weight gain,organ index gain,dyslipidemia,and hepatic lipid deposition in high-fat diet(HFD)-fed mice.Meanwhile,LSP enhanced hepatic antioxidant enzyme activities(superoxide dismutase(SOD)and catalase(CAT))and decreased malondialdehyde(MDA)levels,subsequently alleviated liver injury.In addition,LSP intervention significantly improved insulin sensitivity and glucose tolerance in obese mice,thereby alleviating hyperglycemia and insulin resistance.At the molecular level,LSP intervention up-regulated the mRNA and protein expression of fatty acid oxidation-related genes(FATP1,CPT-1a,ACOX1)and down-regulated the mRNA and protein expression of lipid synthesis-related genes(SREBP-1c,ACC,SCD-1,FASN)by activating the PPARαsignaling pathway,thereby promoting hepatic fatty acid oxidation and reducing lipogenesis.These results demonstrate that LSP has the potential as a dietary supplementation to prevent and ameliorate obesity.展开更多
Currently three major problems seriously limit the practical application of can-cer photodynamic therapy(PDT):(i)the hypoxic tumor microenvironment(TME);(ii)low generation efficiency of toxic reactive oxygen species(R...Currently three major problems seriously limit the practical application of can-cer photodynamic therapy(PDT):(i)the hypoxic tumor microenvironment(TME);(ii)low generation efficiency of toxic reactive oxygen species(ROS)in aggre-gates and(iii)shallow tissue penetration depth of excitation light.Very limited approaches are available for addressing all the above three problems with a single design.Herein,a rational“three birds with one stone”molecular and nanoengi-neering strategy is demonstrated:a photodynamic nanoplatform U-Ir@PAA-ABS based on the covalent combination of lanthanide-doped upconversion nanoparti-cles(UCNPs)and an AIE-active dinuclear Ir(III)complex provides a low oxygen concentration-dependent type-I photochemical process upon 980 nm irradiation by Föster resonance energy transfer(FRET).U-Ir@PAA-ABS targets mitochondria and has excellent phototoxicity even in severe hypoxia environments upon 980 nm irradiation,inducing a dual-mode cell death mechanism by apoptosis and ferropto-sis.Taken together,the in vitro and in vivo results demonstrate a successful strategy for improving the efficacy of PDT against hypoxic tumors.展开更多
Probiotic is a promising nutritional intervention for the prevention and alleviation of type 2 diabetes (T2DM).In this study,the remission potential of a multi-species probiotic (Lactobacillus acidophilus NCFM,Lactoba...Probiotic is a promising nutritional intervention for the prevention and alleviation of type 2 diabetes (T2DM).In this study,the remission potential of a multi-species probiotic (Lactobacillus acidophilus NCFM,Lactobacillus rhamnosus GG,Bifidobacterium lactis HN019 and Streptococcus thermophilus ST447) and its fermented yoghurt on the symptoms of high fat diet and streptozotocin induced T2DM mice were investigated,and the underlying mechanisms were elucidated.Multi-species probiotic and probiotic yoghurt elicited similar but varying efficacy in decreasing the body weight loss,improving organ weight,glucose tolerance and insulin resistance,regulating the levels of blood glucose,HbA1c,insulin and lipid as well as protecting the pancreatic islets.Their tangible antidiabetic effects may be ascribed to the mutual promotion between the repair of the intestinal barrier/permeability and the optimization of gut microbiota structure.Furthermore,the intestinal flora-short chain fatty acids-intestinal hormones/inflammatory pathway was activated and thereby conferring healthy benefits to the host.This proposed probiotic combination appears to provide a viable approach to alleviate T2DM.展开更多
Stretchable ultraviolet photodetectors with fast response have wide applications in wearable electronics and implantable biomedical devices. However, most of the conventional binary oxide nanowires based photodetector...Stretchable ultraviolet photodetectors with fast response have wide applications in wearable electronics and implantable biomedical devices. However, most of the conventional binary oxide nanowires based photodetectors exhibit slow response due to the presence of a large number of surface defects related to trapping centers. Herein, with interlaced SnO2-CdS nanowire films as the sensing materials, we fabricated stretchable ultraviolet photodetectors with significantly improved response speed via a multiple lithographic filtration method. Systematic investigations reveal that the interlaced-nanowire based photodetectors have lower dark current and much higher response speed(more than 100 times) compared with pure SnO2 nanowire based photodetectors. The relevant carrier generation and transport mechanism were also discussed. In addition, due to the formation of waved wrinkles on the surface of the nanowires/PDMS layer during the prestretching cycles, the SnO2-CdS interlaced nanowire photodetectors display excellent electrical stability and stretching cyclability within 50% strain, without obvious performance degradation even after 150 stretching cycles. As a simple and effective strategy to fabricate stretchable ultraviolet photodetectors with high response speed, the interlacednanowire structure can also be applied to other nanowire pairs, like ZnO-CdS interlaced-nanowires. Our method provides a versatile way to fabricate fast speed ultraviolet photodetectors by using interlaced metal oxide nanowires-CdS nanowires structures, which is potential in future stretchable and wearable optoelectronic devices.展开更多
基金supported by the Henan Province Key R&D Project under Grant 241111210400the Henan Provincial Science and Technology Research Project under Grants 252102211047,252102211062,252102211055 and 232102210069+2 种基金the Jiangsu Provincial Scheme Double Initiative Plan JSS-CBS20230474,the XJTLU RDF-21-02-008the Science and Technology Innovation Project of Zhengzhou University of Light Industry under Grant 23XNKJTD0205the Higher Education Teaching Reform Research and Practice Project of Henan Province under Grant 2024SJGLX0126。
文摘Accurate and efficient detection of building changes in remote sensing imagery is crucial for urban planning,disaster emergency response,and resource management.However,existing methods face challenges such as spectral similarity between buildings and backgrounds,sensor variations,and insufficient computational efficiency.To address these challenges,this paper proposes a novel Multi-scale Efficient Wavelet-based Change Detection Network(MewCDNet),which integrates the advantages of Convolutional Neural Networks and Transformers,balances computational costs,and achieves high-performance building change detection.The network employs EfficientNet-B4 as the backbone for hierarchical feature extraction,integrates multi-level feature maps through a multi-scale fusion strategy,and incorporates two key modules:Cross-temporal Difference Detection(CTDD)and Cross-scale Wavelet Refinement(CSWR).CTDD adopts a dual-branch architecture that combines pixel-wise differencing with semanticaware Euclidean distance weighting to enhance the distinction between true changes and background noise.CSWR integrates Haar-based Discrete Wavelet Transform with multi-head cross-attention mechanisms,enabling cross-scale feature fusion while significantly improving edge localization and suppressing spurious changes.Extensive experiments on four benchmark datasets demonstrate MewCDNet’s superiority over comparison methods:achieving F1 scores of 91.54%on LEVIR,93.70%on WHUCD,and 64.96%on S2Looking for building change detection.Furthermore,MewCDNet exhibits optimal performance on the multi-class⋅SYSU dataset(F1:82.71%),highlighting its exceptional generalization capability.
基金supported by the Guangdong High Level Innovation Research Institute(Grant No.2021B0909050006)the National Grand Instrument Project(Grant No.2019YFF01014402)+1 种基金the National Natural Science Foundation of China(Grant No.12205008)support from the National Science Fund for Distinguished Young Scholars(Grant No.12225501)。
文摘Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challenges.In this work,we demonstrate for the firs time that the coherent radiation farfiel patterns from laser–foil interactions can serve as an in situ,real-time,and easy-to-implement diagnostic for an ultraintense laser focus.The laser-driven electron sheets,curved by the spatially varying laser fiel and leaving the targets at nearly the speed of light,produce doughnut-shaped patterns depending on the shapes of the focal spot and the absolute laser intensities.Assisted by particle-in-cell simulations,we can achieve measurements of the intensity and the focal spot,and provide immediate feedback to optimize the focal spots for extremely high intensity.
基金supported by the National Grand Instrument Project(Grant No.2019YFF01014402)the National Key Research and Development Program of China(Grant No.2024YFF0726304)+2 种基金the Guangdong High Level Innovation Research Institute(Grant No.2021B0909050006)the National Natural Science Foundation of China(Grant No.12205008)W.Ma acknowledges support from the National Science Fund for Distinguished Young Scholars(Grant No.12225501)。
文摘Ultra-intense electromagnetic fields exceeding 10^(23)W∕cm^(2)are enabling breakthroughs in compact laser-driven particle accelerators and revealing new quantum electrodynamics(QED)phenomena.However,conventional laser-focusing methods face considerable engineering challenges and require substantial costs.Focusing schemes utilizing plasma optics can produce sub-micrometer focus spots beyond the diffraction limit and substantially enhance the peak intensity;however,owing to significant energy dissipation,they may fail to simultaneously increase the laser fluence.To address these challenges,we propose a focusing scheme employing a near-critical-density hollow plasma fiber(HPF)that utilizes graded refractive index dynamics to boost both laser peak intensity and fluence at the same time.Three-dimensional particle-in-cell simulations demonstrate the HPF’s capability to focus a 4.5-μm-diameter Gaussian beam to a sub-diffraction-limited 0.6-μm-diameter spot.The peak intensity and laser fluence can be enhanced by factors of 22 and 10,respectively,marking a substantial improvement over existing plasma-based focusing schemes.Furthermore,the proposed scheme exhibits wide-range parameter adaptation and high robustness,making it suitable for direct implementation in PW-class ultra-intense laser experiments.
基金National Natural Science Foundation of China(61625404,61888102).
文摘Aligned SnS nanowires arrays were grown via a simple chemical vapor deposition method.As-synthesized SnS nanowires are single crystals grown along the[111]direction.The single SnS nanowire based device showed excellent response to near infrared lights with good responsivity of 267.9 A/W,high external quantum efficiency of 3.12×10^4%and fast response time.Photodetectors were built on the aligned SnS nanowire arrays,exhibiting a light on/off ratio of 3.6,and the response and decay time of 4.5 and 0.7 s,respectively,to 1064 nm light illumination.
基金supported in part by the Fundamental Research Funds for the Central Universities under Grant 2022JBQY004,2022JBZY018 and 2022JBXT001in part by the Basic Research Project of Jiangsu Province Frontier Leading Technology under Grant BK20212002.
文摘This paper presented a novel millimeterwave channel measurement platform for the 6G intelligent railway.This platform used phased array antenna with 64 elements and can support instant bandwidth up to 1 GHz.Combined with improved multi-tone sounding signals,the platform can enhance dynamic measurement capability in high-speed railway scenarios.We performed calibration works about frequency flatness,frequency offset and proved platform reliability with channel emulator based closed-loop verification.We also carried out field trials in high-speed railway carriage scenarios.Based on measurement results,we extracted channel characteristic parameters of path loss,power delay profile and delay spread to further verify the field measurement performance of the platform.
基金supported by the National Basic Research Program of China(No.2006CB601205)the National Natural Science Foundation of China(No.10672027)the Key Project of National Natural Science Foundation of China(No.90816025)
文摘Model I quasi-static nonlinear fracture of aluminum foams is analyzed by considering the effect of microscopic heterogeneity. Firstly, a continuum constitutive model is adopted to account for the plastic compressibility of the metallic foams. The yield strain modeled by a two- parameter Weibull-type function is adopted in the constitutive model. Then, a modified cohesive zone model is established to characterize the fracture behavior of aluminum foams with a cohesive zone ahead of the initial crack. The tensile traction versus local crack opening displacement relation is employed to describe the softening characteristics of the material. And a Weibull statistical model for peak bridging stress within the fracture process zone is used for considering microscopic heterogeneity of aluminum foams. Lastly, the influence of stochastic parameters on the curve of stress-strain is given. Numerical examples are given to illustrate the numerical model presented in this paper and the effects of Weibull parameters and material properties on J-integral are discussed.
基金supported by the National Basic Research Program of China(2006CB601205)the National Natural Science Foundation of China(10672027)the National Outstanding Young Scientist of China (50625414)
文摘Dynamic fracture behavior of a Griffith crack along the interface of an adhesive bonded material under normal loading is studied. The singular integral equations are obtained by employing integral transformation and introducing dislocation density functions. By adopting Gauss-Jacobi integration formula, the problem is reduced to the solution of algebraic equations, and by collocation dots method. their solutions can be obtained Based on the parametric discussions presented in the paper, the following conclusions can be drawn： （1） Mode I dynamic stress intensity factor （DSIF） increases with increasing initial crack length and decreasing visco-elastic layer thickness, revealing distinct size effect; （2） The influence of the visco-elastic adhesive relaxation time on the DSIF should not be ignored.
基金supported by National Natural Science Foundation of China(Nos. 91527303, 21333001,21373020, 61321001)MOST(Nos.2013CB933404,2014CB239302),China
文摘Work function plays a significant role in surface chemistry. Local work function provides the information of local d/pole-d/pole interaction and charge distribution between adsorbates and substrate, highlighting the local charge effect of the targeted spot which is normally smeared out in conventional average work function measurements. Chloroaluminum phthalocyanine （CIA1Pc）, an important optoelectronic molecule with a permanent dipole moment pointing from the Pc ring to the ending CI atom, adsorbed on Au（111） in either Cl-up or Cl-down configuration. Scanning tunneling microscopy/spectroscopy measurements revealed that at the centers of Cl-up and CI-down molecules, the local work functions changed oppositely with respect to the Au（111） substrate. At their Pc lobes, however, the local work functions unanimously increased due to charging effect of the indole lobes in the CIAIPc molecule.
基金supported by the National Natural Science Foundation of China(No.62477037)the Shaanxi Provincial Social Science Foundation Project(No.2024P041)+1 种基金the Youth Innovation Team of Shaanxi Universities“Multi-modal Data Mining and Fusion”,Shaanxi Undergraduate and Higher Education Teaching Reform Research Program(No.23BY195)Xi’an Jiaotong University City College Research Project(No.2024Y01).
文摘Large Language Models(LLMs)exhibit impressive performance across various Natural Language Processing(NLP)tasks due to their robust contextual understanding,content generation and few/zero-shot learning abilities.However,LLMs still show significant limitations while handling with mathematical problems that require complex reasoning skills and interpretable solving processes.Consequently,a series of research efforts have been made in solving mathematical problems using Large Language Models(SMP-LLM).This survey provides a comprehensive review of such endeavors.First,we introduce a two-layer classification system for SMP-LLM:at the primary layer,we categorize extant researches into four classes of solution methods,including:fine-tuning,prompt engineering,collaboration with symbolic solvers,and collaboration with evaluators/validators.At the second layer,we classify mathematical problems into four categories:math word problem,geometry problem,theorem proving,and combinatorial optimization problem.This classification system finds the correlation between solution methods and the categories of mathematical problems.Second,we analyzed typical research works under of each method,and summarized their strengths and weaknesses.Third,we elucidate current mainstream datasets for solving mathematical problems and analyzed how these datasets promote SMP-LLM research from different perspectives.Finally,summarize the challenges that SMP-LLM are facing and highlighted four research directions:geometric analysis,comprehension,and generation of mathematical expressions,indirect reasoning and benchmarks for evaluating mathematical ability.We hope that this survey can provide useful references for researchers interested in SMP-LLM.
基金the financial support from the National Key Research and Development Program of China(Grant No.2024YFF1502600)the Fundamental Research Funds for the Central Universities(Grant Nos.YG2024LC09 and YG2025ZD25)+4 种基金the National Natural Science Foundation of China(Grant Nos.82272054 and 623B2070)the Science and Technology Commission of Shanghai Municipality(Grant Nos.24DIPA00300,24490710800,and 24490790900)the Pujiang Program of Shanghai Magnolia Talent Plan(Grant No.24PJA043)the Shanghai Key Laboratory of Gynecologic Oncology,the Sichuan Science and Technology Program(Grant No.2024ZYD0112)the Start-up Program for New Teachers of Shanghai Jiao Tong University(Grant No.AF0820138)。
文摘Surface-enhanced Raman spectroscopy(SERS),as a great potential label-free tool in metabolite detection,offers a strategy for rapid bacterial identification.However,it still lacks experimentally supported spectral interpretation at the metabolite level for complex biosamples.We present a SERS-based method for reliable bacterial intracellular metabolic profiling using plasmonic colloids with high rapidness and costefficiency.A convolutional neural network model was constructed to accurately classify eight types of bacteria with an overall accuracy as high as 90.44%and identify the key spectral features for classification by Shapley Additive Explanations.Molecule-level interpretation of the SERS metabolic profiles has been further realized in combination with laser desorption/ionization mass spectrometry,evidencing the primary metabolite contribution to the bacterial spectral signatures and molecule-level distinctions among different bacterial types.We provide insights into the mechanism of bacterial identification by label-free SERS and pave the way for interpretable SERS diagnostic tools for various diseases.
基金funded in part by the National Natural Science Foundation of China(62372355,61972305,61871308)in part by the Natural Science Basic Research Program of Shaanxi(2023-JC-zD-39,2024JC-YBMS-520)in part by the Key Research and Development Program of Shaanxi(2021ZDLGY02-03).
文摘As a computer vision task,object detection algorithms can be applied to various real-world sce-narios.However,efficient algorithms often come with a large number of parameters and high computational complexity.To meet the demand for high-performance object detection algorithms on mobile devices and embedded devices with limited computational resources,we propose a new lightweight object detection algorithm called DLE-YOLO.Firstly,we design a novel backbone called dual-branch lightweight excitation network(DLEN)for feature extraction,which is mainly constructed by dual-branch lightweight excitation units(DLEU).DLEU is stacked with different numbers of dual-branch lightweight excitation blocks(DLEB),which can extract comprehensive features and integrate information between different channels of features.Secondly,in order to enhance the network to capture key feature information in the regions of interest,the attention model HS-coordinate attention(HS-CA)is introduced into the network.Thirdly,the localization loss utilizes SIoU loss to further optimize the accuracy of the bounding box.Our method achieves a mAP value of 46.0%on the MS-COCO dataset,which is a 2%mAP improvement compared to the baseline YOLOv5-m,while bringing a 19.3%reduction in parameter count and a 12.9%decrease in GFLOPs.Furthermore,our method outperforms some advanced lightweight object detection algorithms,validating the effectiveness of our approach.
基金funded by the National Key Research and Development Program of China under Grants 2023YFC3011500 and 2024YFC3016000.
文摘Emergency communication in forested environments encounters extremely complex propagation conditions,whose channel characteristics cannot be accurately captured by conventional models designed for urban scenarios.This paper conducts field measurements and modeling for 380 MHz vehicle-to-infrastructure(V2I)links in the primeval forest of the Greater Khingan Mountains.Through joint analysis of large-scale and small-scale channel characteristics,we systematically reveal the signal attenuation,fading mechanisms,and delay spread behavior in such environments.Results indicate that for path loss modeling,the Alpha-Beta model outperforms the Close-In model in characterizing the rapid attenuation in dense foliage.Small-scale fading is predominantly Rayleigh-distributed,while Ricean fading only dominates in the initial stage,with its K-factor decreasing significantly as distance increases.The root mean square(RMS)delay spread ranges from 0 to 450 ns,follows a log-normal distribution,and is markedly larger than in urban scenarios.Based on these observations,a parametric tapped-delay-line(TDL)model is developed,effectively quantifying multipath delay,power decay,and fading characteristics.The proposed model can reproduce realistic propagation features in simulations,offering theoretical support for emergency communication system planning and optimization,as well as engineering guidance for enhancing communication reliability and coverage in disaster rescue scenarios.
基金Defense Advanced Research Projects Agency(HR0011-22-2-0008,N660012424000)National Science Foundation(2023775)。
文摘Optical frequency division(OFD)produces low-noise microwave and millimeter-wave(mmWave)signals by transferring the exceptional stability of optical references to electronic frequency domains.Recent developments in integrated optical references and soliton microcombs have paved the way for miniaturizing OFD oscillators to chip scale.Critical to this realization is a rapid tunable frequency comb that is stabilized to the optical references,thereby coherently linking optical and electronic frequencies.In this work,we advance the on-chip OFD technology using an integrated high-speed lead zirconate titanate(PZT)stress-optic actuator on the SiN soliton microcomb resonator.The integrated PZT actuator tunes the resonance frequency of the soliton-generating microresonator with a bandwidth exceeding 10s MHz and thus adjusts the soliton repetition rate.Optical frequency division and low-noise mmWave generation are demonstrated by feedback control of the soliton repetition rate through the integrated PZT-actuator,and the soliton microcomb is stabilized to a pair of reference lasers that are locked to an integrated 4 m SiN coil reference cavity.Our approach provides a fast,versatile,and integrated control mechanism for OFD oscillators and their applications in advanced communications,sensing,and precise timing.
基金support from the National Key Research and Development Program of China(Grant No.2021YFA0715603)National Natural Science Foundation of China(Grant No.62275101,22075101,62075217,and 62305329)+2 种基金Program for the Development of Science and Technology of Jilin province(Item No.YDZJ202201ZYTS300)Changchun Science and Technology Bureau(Grant No.23GZZ06)the China Postdoctoral Science Foundation(Grant No.2023M733432).
文摘In perovskite solar cells(PSCs),chemical bath deposition(CBD)is promising as the core technique for preparing a commercial electron transport layer(ETL)because the film prepared by CBD exhibits excellent uniform and conformal coverage of the substrate.However,metal oxide(MO_(x))films prepared through CBD often have defects on the surface like oxygen vacancies and hydroxyl that limit the PSCs efficiency and degrade the long-term stability.
基金supported by Open Project of Key Laboratory of Agro-Products Processing and Storage(S2023KFKT-13).
文摘Obesity,one of the prevalent chronic diseases globally,is a serious threat to human health.Dietary natural compounds intervention is an effective means to alleviate obesity.The objective of this study was to investigate the potential protective role of lotus seed protein(LSP)against obesity.The results of amino acid composition analysis indicated that LSP possessed a well-balanced distribution of amino acids and was rich in branched-chain amino acids(BCAAs).Meanwhile,LSP exhibited better ABTS radical scavenging,DPPH radical scavenging,hydroxyl radical scavenging,and Fe^(2+)chelating ability in vitro.In vivo,LSP intervention remarkably alleviated body weight gain,organ index gain,dyslipidemia,and hepatic lipid deposition in high-fat diet(HFD)-fed mice.Meanwhile,LSP enhanced hepatic antioxidant enzyme activities(superoxide dismutase(SOD)and catalase(CAT))and decreased malondialdehyde(MDA)levels,subsequently alleviated liver injury.In addition,LSP intervention significantly improved insulin sensitivity and glucose tolerance in obese mice,thereby alleviating hyperglycemia and insulin resistance.At the molecular level,LSP intervention up-regulated the mRNA and protein expression of fatty acid oxidation-related genes(FATP1,CPT-1a,ACOX1)and down-regulated the mRNA and protein expression of lipid synthesis-related genes(SREBP-1c,ACC,SCD-1,FASN)by activating the PPARαsignaling pathway,thereby promoting hepatic fatty acid oxidation and reducing lipogenesis.These results demonstrate that LSP has the potential as a dietary supplementation to prevent and ameliorate obesity.
基金NSFC,Grant/Award Numbers:52073045,51773195Key Scientific and Technological Project of Jilin Province,Grant/Award Number:20190701010GH+2 种基金Development and Reform Commission of Jilin Province,Grant/Award Number:2020C035-5Changchun Science and Technology Bureau,Grant/Award Number:21ZGY19EPSRC,Grant/Award Number:EP/L02621X/1。
文摘Currently three major problems seriously limit the practical application of can-cer photodynamic therapy(PDT):(i)the hypoxic tumor microenvironment(TME);(ii)low generation efficiency of toxic reactive oxygen species(ROS)in aggre-gates and(iii)shallow tissue penetration depth of excitation light.Very limited approaches are available for addressing all the above three problems with a single design.Herein,a rational“three birds with one stone”molecular and nanoengi-neering strategy is demonstrated:a photodynamic nanoplatform U-Ir@PAA-ABS based on the covalent combination of lanthanide-doped upconversion nanoparti-cles(UCNPs)and an AIE-active dinuclear Ir(III)complex provides a low oxygen concentration-dependent type-I photochemical process upon 980 nm irradiation by Föster resonance energy transfer(FRET).U-Ir@PAA-ABS targets mitochondria and has excellent phototoxicity even in severe hypoxia environments upon 980 nm irradiation,inducing a dual-mode cell death mechanism by apoptosis and ferropto-sis.Taken together,the in vitro and in vivo results demonstrate a successful strategy for improving the efficacy of PDT against hypoxic tumors.
基金financially supported by the Key Special Projects of the Ministry of Science and Technology(SQ2020YFF0419518)China Scholarship Council(no.202006120438,Beijing).
文摘Probiotic is a promising nutritional intervention for the prevention and alleviation of type 2 diabetes (T2DM).In this study,the remission potential of a multi-species probiotic (Lactobacillus acidophilus NCFM,Lactobacillus rhamnosus GG,Bifidobacterium lactis HN019 and Streptococcus thermophilus ST447) and its fermented yoghurt on the symptoms of high fat diet and streptozotocin induced T2DM mice were investigated,and the underlying mechanisms were elucidated.Multi-species probiotic and probiotic yoghurt elicited similar but varying efficacy in decreasing the body weight loss,improving organ weight,glucose tolerance and insulin resistance,regulating the levels of blood glucose,HbA1c,insulin and lipid as well as protecting the pancreatic islets.Their tangible antidiabetic effects may be ascribed to the mutual promotion between the repair of the intestinal barrier/permeability and the optimization of gut microbiota structure.Furthermore,the intestinal flora-short chain fatty acids-intestinal hormones/inflammatory pathway was activated and thereby conferring healthy benefits to the host.This proposed probiotic combination appears to provide a viable approach to alleviate T2DM.
基金supported by the National Natural Science Foundation of China(61625404,61888102 and 61574132)the Key Research Program of Frontier Sciences,CAS(QYZDY-SSWJWC004)
文摘Stretchable ultraviolet photodetectors with fast response have wide applications in wearable electronics and implantable biomedical devices. However, most of the conventional binary oxide nanowires based photodetectors exhibit slow response due to the presence of a large number of surface defects related to trapping centers. Herein, with interlaced SnO2-CdS nanowire films as the sensing materials, we fabricated stretchable ultraviolet photodetectors with significantly improved response speed via a multiple lithographic filtration method. Systematic investigations reveal that the interlaced-nanowire based photodetectors have lower dark current and much higher response speed(more than 100 times) compared with pure SnO2 nanowire based photodetectors. The relevant carrier generation and transport mechanism were also discussed. In addition, due to the formation of waved wrinkles on the surface of the nanowires/PDMS layer during the prestretching cycles, the SnO2-CdS interlaced nanowire photodetectors display excellent electrical stability and stretching cyclability within 50% strain, without obvious performance degradation even after 150 stretching cycles. As a simple and effective strategy to fabricate stretchable ultraviolet photodetectors with high response speed, the interlacednanowire structure can also be applied to other nanowire pairs, like ZnO-CdS interlaced-nanowires. Our method provides a versatile way to fabricate fast speed ultraviolet photodetectors by using interlaced metal oxide nanowires-CdS nanowires structures, which is potential in future stretchable and wearable optoelectronic devices.
