Understanding the properties of warm dense hydrogen is of key importance for the modeling of compact astrophysical objects and to understand and further optimize inertial confinement fusion applications.The workhorse ...Understanding the properties of warm dense hydrogen is of key importance for the modeling of compact astrophysical objects and to understand and further optimize inertial confinement fusion applications.The workhorse of warm dense matter theory is thermal density functional theory(DFT),which,however,suffers from two limitations:(i)its accuracy can depend on the utilized exchange-correlation functional,which has to be approximated,and(ii)it is generally limited to single-electron properties such as the density distribution.Here,we present a new ansatz combining time-dependent DFT results for the dynamic structure factor S_(ee)(q,ω)with static DFT results for the density response.This allows us to estimate the electron-electron static structure factor S_(ee)(q)of warm dense hydrogen with high accuracy over a broad range of densities and temperatures.In addition to its value for the study of warm dense matter,our work opens up new avenues for the future study of electronic correlations exclusively within the framework of DFT for a host of applications.展开更多
In fire rescue scenarios,traditional manual operations are highly dangerous,as dense smoke,low visibility,extreme heat,and toxic gases not only hinder rescue efficiency but also endanger firefighters’safety.Although ...In fire rescue scenarios,traditional manual operations are highly dangerous,as dense smoke,low visibility,extreme heat,and toxic gases not only hinder rescue efficiency but also endanger firefighters’safety.Although intelligent rescue robots can enter hazardous environments in place of humans,smoke poses major challenges for human detection algorithms.These challenges include the attenuation of visible and infrared signals,complex thermal fields,and interference frombackground objects,all ofwhichmake it difficult to accurately identify trapped individuals.To address this problem,we propose VIF-YOLO,a visible–infrared fusion model for real-time human detection in dense smoke environments.The framework introduces a lightweight multimodal fusion(LMF)module based on learnable low-rank representation blocks to end-to-end integrate visible and infrared images,preserving fine details while enhancing salient features.In addition,an efficient multiscale attention(EMA)mechanism is incorporated into the YOLOv10n backbone to improve feature representation under low-light conditions.Extensive experiments on our newly constructedmultimodal smoke human detection(MSHD)dataset demonstrate thatVIF-YOLOachievesmAP50 of 99.5%,precision of 99.2%,and recall of 99.3%,outperforming YOLOv10n by a clear margin.Furthermore,when deployed on the NVIDIA Jetson Xavier NX,VIF-YOLO attains 40.6 FPS with an average inference latency of 24.6 ms,validating its real-time capability on edge-computing platforms.These results confirm that VIF-YOLO provides accurate,robust,and fast detection across complex backgrounds and diverse smoke conditions,ensuring reliable and rapid localization of individuals in need of rescue.展开更多
The Haicheng region,Liaoning,China,likely hosts a conjugate fault system comprising the NW-trending Haichenghe fault and NE-trending secondary faults.On February 4,1975,at 19:36 CST,an earthquake of M_(S)7.3 and inten...The Haicheng region,Liaoning,China,likely hosts a conjugate fault system comprising the NW-trending Haichenghe fault and NE-trending secondary faults.On February 4,1975,at 19:36 CST,an earthquake of M_(S)7.3 and intensity(MMI)IX hit the city of Haicheng,Liaoning,China.Although deep seismic profiling was previously conducted along the Haichenghe fault,the limited horizontal resolution in the shallow part prevented the recognition of kilometer-scale anomalies.The velocity structure characteristics of the Haichenghe fault and its NE-trending conjugate faults remain unclear.Using the extended range phase shift method,the high-resolution S-wave velocity structures are obtained by deploying a long,dense linear array of 55 short-period seismometers across the fault and NE-trending conjugate faults.The array length was 32 km and inter-station spacing was approximately 600 m,facilitating the collection of approximately 22 days of continuous waveform data.Employing the Extended Range Phase Shift(ERPS)method enabled the extraction of broadband 0.2–5 s Rayleigh wave phase velocity dispersion curves.The broadband dispersion data were used for inversion of the high-resolution S-wave velocity structure to a depth of 8 km from the surface.The velocity structure characteristics and seismicity of the Haichenghe fault and NE-trending conjugate faults were analyzed and compared with nearby fault gas measurements.Results show(1)shallow S-wave velocities show a low-high-low horizontal distribution,corresponding to basin-uplift-basin topography;(2)significant velocity contrasts occur across the Haichenghe fault:its SW segment(0–17 km)exhibits high velocities consistent with Paleoproterozoic crystalline basement(Pt_(1)),while the NE segment(17–32 km)shows low velocities related to Yanshanian intrusions(γ_(5))and Quaternary sediments.NE-trending conjugate faults display sharp velocity gradients marking fracture locations,with all faults being near-vertical to~8 km depth;(3)seismicity at 1–6 km depth mainly clusters in high-velocity zones;at 6–8 km depth,it concentrates beneath the Haichenghe fault in low-velocity areas and along NE-trending faults;(4)the seismic activity characteristics and fault zone width of the Haicheng he fault reflected by velocity imaging results are basically consistent with those obtained by the fault gas measurement method.展开更多
Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further developme...Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further development.Herein,potassium acetate(KAc) additive with cation/anion synergy effect is added into the ZnSO_(4) electrolyte to effectively promote the oriented uniform Zn deposition and suppress side reactions.According to density functional theory calculation and experimental results,CH_(3)COO^(-)(Ac^(-))anions are capable of forming stronger hydrogen bonds with H_(2)O molecules,leading to an expanded electrochemical stability window,reduced the reactivity of H_(2)O,and hence suppressing HER.Meanwhile,Ac-anions can also preferentially adsorb onto the Zn anode,promoting dense deposition towards the(100) crystal plane.Besides,dissociated K^(+) ions serve as electrostatic shielding cations,which significantly promote uniform Zn deposition and prevent dendrite formation.Thus,the Zn||Zn symmetric cell demonstrates an impressive cycle lifespan of 3000 h at 1.0 m A/cm^(2).Furthermore,the Zn||MnO_(2) full battery exhibits superior stability with a capacity retention of 86.95 % at 2.0 A/g after 4000 cycles.Therefore,the cation/anion synergy effect in KAc additive offers a viable solution to address HER and hinder dendrite growth at the interface of Zn anodes.展开更多
Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instr...Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instrument function,is measured in X-ray Thom-son scattering(XRTS)experiments,which allow the study of electronic structure properties at the microscopic level.Among the various ab initio methods,linear-response time-dependent density-functional theory(LR-TDDFT)is a key framework for simulating the DSF.The standard approach in LR-TDDFT for computing the DSF relies on the orbital representation.A significant drawback of this method is the unfavorable scaling of the number of required empty bands as the wavenumber increases,making LR-TDDFT impractical for modeling XRTS measurements over large energy scales,such as in backward scattering geometry.In this work,we consider and test an alternative approach to LR-TDDFT that employs the Liouville–Lanczos(LL)method for simulating the DSF of WDM.This approach does not require empty states and allows the DSF at large momentum transfer values and over a broad frequency range to be accessed.We compare the results obtained from the LL method with those from the solution of Dyson’s equation using the standard LR-TDDFT within the projector augmented-wave formalism for isochorically heated aluminum and warm dense hydrogen.Additionally,we utilize exact path integral Monte Carlo results for the imaginary-time density-density correlation function(ITCF)of warm dense hydrogen to rigorously benchmark the LL approach.We discuss the application of the LL method for calculating DSFs and ITCFs at different wavenumbers,the effects of pseudopotentials,and the role of Lorentzian smearing.The successful validation of the LL method under WDM conditions makes it a valuable addition to the ab initio simulation landscape,supporting experimental efforts and advancing WDM theory.展开更多
Dear Editor,This letter focuses on the fact that small objects with few pixels disappear in feature maps with large receptive fields, as the network deepens, in object detection tasks. Therefore, the detection of dens...Dear Editor,This letter focuses on the fact that small objects with few pixels disappear in feature maps with large receptive fields, as the network deepens, in object detection tasks. Therefore, the detection of dense small objects is challenging.展开更多
Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based elect...Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based electrode exhibit multi-scale structural characteristics including macroscopic electrode morphologies,mesoscopic microcrystals and pores,and microscopic defects and dopants in the carbon basal plane.Therefore,the ordered combination of multi-scale structures of carbon electrode is crucial for achieving dense energy storage and high volumetric performance by leveraging the functions of various scale structu re.Considering that previous reviews have focused more on the discussion of specific scale structu re of carbon electrodes,this review takes a multi-scale perspective in which recent progresses regarding the structureperformance relationship,underlying mechanism and directional design of carbon-based multi-scale structures including carbon morphology,pore structure,carbon basal plane micro-environment and electrode technology on dense energy storage and volumetric property of supercapacitors are systematically discussed.We analyzed in detail the effects of the morphology,pore,and micro-environment of carbon electrode materials on ion dense storage,summarized the specific effects of different scale structures on volumetric property and recent research progress,and proposed the mutual influence and trade-off relationship between various scale structures.In addition,the challenges and outlooks for improving the dense storage and volumetric performance of carbon-based supercapacitors are analyzed,which can provide feasible technical reference and guidance for the design and manufacture of dense carbon-based electrode materials.展开更多
The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velo...The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velocity models are available for the LMS fault zone,high-resolution velocity models are lacking.Therefore,a dense array of 240 short-period seismometers was deployed around the central segment of the LMS fault zone for approximately 30 days to monitor earthquakes and characterize fine structures of the fault zone.Considering the large quantity of observed seismic data,the data processing workflow consisted of deep learning-based automatic earthquake detection,phase arrival picking,and association.Compared with the earthquake catalog released by the China Earthquake Administration,many more earthquakes were detected by the dense array.Double-difference seismic tomography was adopted to determine V_(p),V_(s),and V_(p)/V_(s)models as well as earthquake locations.The checkerboard test showed that the velocity models have spatial resolutions of approximately 5 km in the horizontal directions and 2 km at depth.To the west of the Yingxiu–Beichuan Fault(YBF),the Precambrian Pengguan complex,where most of earthquakes occurred,is characterized by high velocity and low V_(p)/V_(s)values.In comparison,to the east of the YBF,the Upper Paleozoic to Jurassic sediments,where few earthquakes occurred,show low velocity and high V_(p)/V_(s)values.Our results suggest that the earthquake activity in the LMS fault zone is controlled by the strength of the rock compositions.When the high-resolution velocity models were combined with the relocated earthquakes,we were also able to delineate the fault geometry for different faults in the LMS fault zone.展开更多
Currently,there is a lack of in-situ or model test results for cone penetration tests(CPTs)conducted in deep,dense sand layers under high overburden stresses,restricting the development of empirical relationships betw...Currently,there is a lack of in-situ or model test results for cone penetration tests(CPTs)conducted in deep,dense sand layers under high overburden stresses,restricting the development of empirical relationships between CPT results and the characteristics of such deep,dense sand layers.This study addresses this gap by proposing an empirical relationship to predict the relative density of dense silica sand based on stress level and cone tip resistance.The relationship was developed through CPTs performed in a calibration chamber using dense sand specimens(with relative densities of 74%-91%)subjected to high stresses(under overburden stresses of 0.5-2.0 MPa)and numerical simulations employing the large deformation finite element method.The Arbitrary Lagrangian Eulerian method was used to regularly regenerate the mesh to prevent soil element distortion around the cone tip.Additionally,the modified Mohr-Coulomb model was integrated to capture the stress-strain behavior of dense silica sand under high stresses.A reasonable agreement was achieved between the numerical and experimental penetration profiles,which verifies the reliability of the numerical model.A sufficient number of parametric analyses were carried out,and then an empirical equation was proposed to establish the relationship between the relative density of dense sand,stress level and cone resistance.The empirical equation provides predictions with acceptable accuracy,as the discrepancies between the predicted and measured relative density values fall within±30%.展开更多
Reliable electricity infrastructure is critical for modern society,highlighting the importance of securing the stability of fundamental power electronic systems.However,as such systems frequently involve high-current ...Reliable electricity infrastructure is critical for modern society,highlighting the importance of securing the stability of fundamental power electronic systems.However,as such systems frequently involve high-current and high-voltage conditions,there is a greater likelihood of failures.Consequently,anomaly detection of power electronic systems holds great significance,which is a task that properly-designed neural networks can well undertake,as proven in various scenarios.Transformer-like networks are promising for such application,yet with its structure initially designed for different tasks,features extracted by beginning layers are often lost,decreasing detection performance.Also,such data-driven methods typically require sufficient anomalous data for training,which could be difficult to obtain in practice.Therefore,to improve feature utilization while achieving efficient unsupervised learning,a novel model,Densely-connected Decoder Transformer(DDformer),is proposed for unsupervised anomaly detection of power electronic systems in this paper.First,efficient labelfree training is achieved based on the concept of autoencoder with recursive-free output.An encoder-decoder structure with densely-connected decoder is then adopted,merging features from all encoder layers to avoid possible loss of mined features while reducing training difficulty.Both simulation and real-world experiments are conducted to validate the capabilities of DDformer,and the average FDR has surpassed baseline models,reaching 89.39%,93.91%,95.98%in different experiment setups respectively.展开更多
Shallow gas can cause many disasters,and it is reported in many marine engineering constructions.For this,it is imperative to understand the impact of gas on the mechanical behaviors of soil.This study investigated th...Shallow gas can cause many disasters,and it is reported in many marine engineering constructions.For this,it is imperative to understand the impact of gas on the mechanical behaviors of soil.This study investigated the influence of undrained triaxial compression tests on dense gassy sand commonly encountered in coastal areas.Triaxial tests were performed on specimens with saturations of 100%,99.8%,95.9%,and 92.7% under confining pressures of 50 kPa and 200 kPa by a self-developed multipurpose integrated triaxial apparatus(MITA)for gassy soil.The results are presented in terms of monotonic stress‒strain behavior,volumetric behavior,shear strength,and excess pore water pressure(EPWP).The occurrence of gas bubbles has different effects on loose and dense sands,augmenting the undrained shear strength of loose sand while concurrently diminishing that of dense sand.The deviatoric stress of dense sand increases during shear shrinkage,which is similar to the characteristics of loose sand under the influence of gas bubbles.However,following sand dilation,the effect of gas bubbles on deviatoric stress manifests in an antithetical manner.With elevated gas content,the shear strength of dense sand decreases,accompanied by a deceleration in the development of EPWP and a notable increase in volumetric changes.To this end,a microscopic explanation concerning the deformation and evolution of gas bubbles within sand during the shear process was presented to reveal the macroscopic laws governing the undrained shear attributes of dense gassy sand.展开更多
The aftershocks of the 1975 M_(S)7.3 Haicheng and 1999 M_(S)5.4 Xiuyan earthquakes have persisted for a long time.The ChinArray-III dense stations,deployed in eastern North China from 2018 to 2020,increased seismic mo...The aftershocks of the 1975 M_(S)7.3 Haicheng and 1999 M_(S)5.4 Xiuyan earthquakes have persisted for a long time.The ChinArray-III dense stations,deployed in eastern North China from 2018 to 2020,increased seismic monitoring capability in the Haicheng-Xiuyan region,which can facilitate the construction of high-precision earthquake catalogs to better clarify the fault structures and seismogenic mechanisms of the two earthquakes.In this study,we selected 15 permanent stations and 37 ChinArray-III stations within 150 km of the epicenter of the Haicheng Earthquake.Next,we used deep learning methods to pick P-and S-wave phases from continuous waveforms recorded at these stations from January 2018 to July 2020.Based on these picks,we constructed an automatic earthquake catalog of the Haicheng-Xiuyan region.Compared with the routine manual catalog by China Earthquake Networks Center(CENC),our catalog contains 9.7 times more seismic events,including 98.3%of the seismic events in the CENC catalog,and has a lower magnitude of completeness(M_(c)=1.1 vs M_(c)=1.8 for the CENC catalog).The relocated events indicate that the strike of the Haichenghe-Dayanghe fault varies considerably from northwest to southeast,indicating that the fault bends slightly around the hypocenter of the 1975 M_(S)7.3 Haicheng earthquake which may act as a channel for fluid migration.The weak seismicity in the area between Haicheng and Xiuyan indicates that the fault section may be locked.Furthermore,the 1999 M_(S)5.4 Xiuyan earthquake and its aftershock sequence occurred on the Kangjialing fault and its ENE-trending conjugate fault,and the intersection of the two faults coincides with the source areas of the 1999 M_(S)5.4 and 2000 M_(S)5.1 Xiuyan earthquakes.Therefore,the Xiuyan earthquake sequence may be controlled by the Kangjialing fault and its conjugate fault.This study shows that the automatic earthquake catalog,obtained by deep learning methods and dense seismic array,can provide valuable information for fault structures and the seismogenic mechanisms of moderate-to-strong earthquakes.展开更多
The evolution of cracks in shale directly affects the efficient production of shale gas.However,there is a lack of research on the characteristics of crack initiation in deep dense shale under different stress conditi...The evolution of cracks in shale directly affects the efficient production of shale gas.However,there is a lack of research on the characteristics of crack initiation in deep dense shale under different stress conditions.In this work,considering the different combinations of confining pressure and bedding plane inclination angle(α),biaxial mechanical loading experiments were conducted on shale containing circular holes.The research results indicate that the confining pressure and inclination angle of the bedding planes significantly influence the failure patterns of shale containing circular holes.The instability of shale containing circular holes can be classified into five types:tensile failure along the bedding planes,tensile failure through the bedding planes,shear slip along the bedding planes,shear failure through the bedding planes,and block instability failure.Furthermore,the evolution of strain and stress fields around the circular holes was found to be the fundamental cause of variations in the initiation characteristics and locations of shale cracks.The crack initiation criterion for shale containing circular hole was established,providing a new method for evaluating the trajectory of shale hole wall fractures.This study holds significant importance for evaluating the evolution and stability of fracture networks within shale reservoirs.展开更多
Aiming at the problem of mobile data traffic surge in 5G networks,this paper proposes an effective solution combining massive multiple-input multiple-output techniques with Ultra-Dense Network(UDN)and focuses on solvi...Aiming at the problem of mobile data traffic surge in 5G networks,this paper proposes an effective solution combining massive multiple-input multiple-output techniques with Ultra-Dense Network(UDN)and focuses on solving the resulting challenge of increased energy consumption.A base station control algorithm based on Multi-Agent Proximity Policy Optimization(MAPPO)is designed.In the constructed 5G UDN model,each base station is considered as an agent,and the MAPPO algorithm enables inter-base station collaboration and interference management to optimize the network performance.To reduce the extra power consumption due to frequent sleep mode switching of base stations,a sleep mode switching decision algorithm is proposed.The algorithm reduces unnecessary power consumption by evaluating the network state similarity and intelligently adjusting the agent’s action strategy.Simulation results show that the proposed algorithm reduces the power consumption by 24.61% compared to the no-sleep strategy and further reduces the power consumption by 5.36% compared to the traditional MAPPO algorithm under the premise of guaranteeing the quality of service of users.展开更多
Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages ...Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages of amorphous materials to optimize the interfacial structure for efficient Na^(+)storage.Herein,the dense homologous amorphous/crystalline heterointerfaces are in situ achieved in N-doped carbon nanobundles via self-polymerization and precise nitriding(Mo–N/Mo_(2)N@C).The amorphous Mo–N rich in unsaturated vacancy defects provides abundant active sites with isotropic ion-transport channels,and can effectively alleviate structural stress from crystalline Mo_(2)N.Meanwhile,the conductive Mo_(2)N can facilitate effective electron transfer,augmented further by the carbon encapsulation.Theoretical calculations reveal that the dense heterointerfaces can optimize the electronic structure and shift the d-p orbital centers of Mo and N upward,thereby enhancing the adsorption and mobility of Na^(+),and ultimately improving the charge transport and storage efficiency of the electrode.The Mo–N/Mo_(2)N@C as an anode delivers a 46.9%increase in reversible capacity over Mo_(2)N@C,reaching 461.1 m Ah.g^(–1)at 0.1 A.g^(–1),along with improved rate capability and cycling stability,underlining its practical utility.These results suggest that the homologous interfacial coupling can boost the storage properties of nitrides,providing a valuable reference for improving the properties of electrodes with low theoretical capacities.展开更多
基金partially supported by the Center for Advanced Systems Understanding (CASUS), financed by Germany’s Federal Ministry of Education and Research and the Saxon State Government out of the State Budget approved by the Saxon State Parliamentthe European Union’s Just Transition Fund (JTF) within the project Röntgenlaser Optimierung der Laserfusion (ROLF), Contract No. 5086999001, co-financed by the Saxon State Government out of the State Budget approved by the Saxon State Parliament+3 种基金the European Research Council (ERC) under the European Union’s Horizon 2022 Research and Innovation Programme (Grant Agreement No. 101076233, “PREXTREME”)Computations were performed on a Bull Cluster at the Center for Information Services and High-Performance Computing (ZIH) at Technische Universität Dresden and at the Norddeutscher Verbund für Hoch- und Höchstleistungsrechnen (HLRN) under Grant No. mvp00024support by the National Natural Science Foundation of China under Grant No. 12274171support by the Advanced Materials–National Science and Technology Major Project (Grant No. 2024ZD0606900)
文摘Understanding the properties of warm dense hydrogen is of key importance for the modeling of compact astrophysical objects and to understand and further optimize inertial confinement fusion applications.The workhorse of warm dense matter theory is thermal density functional theory(DFT),which,however,suffers from two limitations:(i)its accuracy can depend on the utilized exchange-correlation functional,which has to be approximated,and(ii)it is generally limited to single-electron properties such as the density distribution.Here,we present a new ansatz combining time-dependent DFT results for the dynamic structure factor S_(ee)(q,ω)with static DFT results for the density response.This allows us to estimate the electron-electron static structure factor S_(ee)(q)of warm dense hydrogen with high accuracy over a broad range of densities and temperatures.In addition to its value for the study of warm dense matter,our work opens up new avenues for the future study of electronic correlations exclusively within the framework of DFT for a host of applications.
基金funded by the National Natural Science Foundation of China under Grant 62306128the Leading Innovation Project of Changzhou Science and Technology Bureau underGrant CQ20230072+2 种基金the Basic Science Research Project of Jiangsu Provincial Department of Education under Grant 23KJD520003the Science and Technology Development Plan Project of Jilin Provinceunder Grant 20240101382JCthe National KeyR esearch and Development Program of China under Grant 2023YFF1105102.
文摘In fire rescue scenarios,traditional manual operations are highly dangerous,as dense smoke,low visibility,extreme heat,and toxic gases not only hinder rescue efficiency but also endanger firefighters’safety.Although intelligent rescue robots can enter hazardous environments in place of humans,smoke poses major challenges for human detection algorithms.These challenges include the attenuation of visible and infrared signals,complex thermal fields,and interference frombackground objects,all ofwhichmake it difficult to accurately identify trapped individuals.To address this problem,we propose VIF-YOLO,a visible–infrared fusion model for real-time human detection in dense smoke environments.The framework introduces a lightweight multimodal fusion(LMF)module based on learnable low-rank representation blocks to end-to-end integrate visible and infrared images,preserving fine details while enhancing salient features.In addition,an efficient multiscale attention(EMA)mechanism is incorporated into the YOLOv10n backbone to improve feature representation under low-light conditions.Extensive experiments on our newly constructedmultimodal smoke human detection(MSHD)dataset demonstrate thatVIF-YOLOachievesmAP50 of 99.5%,precision of 99.2%,and recall of 99.3%,outperforming YOLOv10n by a clear margin.Furthermore,when deployed on the NVIDIA Jetson Xavier NX,VIF-YOLO attains 40.6 FPS with an average inference latency of 24.6 ms,validating its real-time capability on edge-computing platforms.These results confirm that VIF-YOLO provides accurate,robust,and fast detection across complex backgrounds and diverse smoke conditions,ensuring reliable and rapid localization of individuals in need of rescue.
基金supported by the Special Fund of the Institute of Geophysics,China Earthquake Administration,(No.DQJB21B34).
文摘The Haicheng region,Liaoning,China,likely hosts a conjugate fault system comprising the NW-trending Haichenghe fault and NE-trending secondary faults.On February 4,1975,at 19:36 CST,an earthquake of M_(S)7.3 and intensity(MMI)IX hit the city of Haicheng,Liaoning,China.Although deep seismic profiling was previously conducted along the Haichenghe fault,the limited horizontal resolution in the shallow part prevented the recognition of kilometer-scale anomalies.The velocity structure characteristics of the Haichenghe fault and its NE-trending conjugate faults remain unclear.Using the extended range phase shift method,the high-resolution S-wave velocity structures are obtained by deploying a long,dense linear array of 55 short-period seismometers across the fault and NE-trending conjugate faults.The array length was 32 km and inter-station spacing was approximately 600 m,facilitating the collection of approximately 22 days of continuous waveform data.Employing the Extended Range Phase Shift(ERPS)method enabled the extraction of broadband 0.2–5 s Rayleigh wave phase velocity dispersion curves.The broadband dispersion data were used for inversion of the high-resolution S-wave velocity structure to a depth of 8 km from the surface.The velocity structure characteristics and seismicity of the Haichenghe fault and NE-trending conjugate faults were analyzed and compared with nearby fault gas measurements.Results show(1)shallow S-wave velocities show a low-high-low horizontal distribution,corresponding to basin-uplift-basin topography;(2)significant velocity contrasts occur across the Haichenghe fault:its SW segment(0–17 km)exhibits high velocities consistent with Paleoproterozoic crystalline basement(Pt_(1)),while the NE segment(17–32 km)shows low velocities related to Yanshanian intrusions(γ_(5))and Quaternary sediments.NE-trending conjugate faults display sharp velocity gradients marking fracture locations,with all faults being near-vertical to~8 km depth;(3)seismicity at 1–6 km depth mainly clusters in high-velocity zones;at 6–8 km depth,it concentrates beneath the Haichenghe fault in low-velocity areas and along NE-trending faults;(4)the seismic activity characteristics and fault zone width of the Haicheng he fault reflected by velocity imaging results are basically consistent with those obtained by the fault gas measurement method.
基金financially supported by the National Natural Science Foundation of China (No.52372188)the 111 Project (No.D17007)2023 Introduction of studying abroad talent program。
文摘Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further development.Herein,potassium acetate(KAc) additive with cation/anion synergy effect is added into the ZnSO_(4) electrolyte to effectively promote the oriented uniform Zn deposition and suppress side reactions.According to density functional theory calculation and experimental results,CH_(3)COO^(-)(Ac^(-))anions are capable of forming stronger hydrogen bonds with H_(2)O molecules,leading to an expanded electrochemical stability window,reduced the reactivity of H_(2)O,and hence suppressing HER.Meanwhile,Ac-anions can also preferentially adsorb onto the Zn anode,promoting dense deposition towards the(100) crystal plane.Besides,dissociated K^(+) ions serve as electrostatic shielding cations,which significantly promote uniform Zn deposition and prevent dendrite formation.Thus,the Zn||Zn symmetric cell demonstrates an impressive cycle lifespan of 3000 h at 1.0 m A/cm^(2).Furthermore,the Zn||MnO_(2) full battery exhibits superior stability with a capacity retention of 86.95 % at 2.0 A/g after 4000 cycles.Therefore,the cation/anion synergy effect in KAc additive offers a viable solution to address HER and hinder dendrite growth at the interface of Zn anodes.
基金supported by the Center for Advanced Systems Understanding(CASUS),financed by Germany’s Federal Ministry of Education and Research(BMBF)and the Saxon State Government out of the State Budget approved by the Saxon State Parliamentfunding from the European Research Council(ERC)under the European Union’s Horizon 2022 research and innovation programme(Grant Agreement No.101076233,“PREXTREME”)funding from the European Union’s Just Transition Fund(JTF)within the project Röntgenlaser-Optimierung der Laserfusion(ROLF),Contract No.5086999001,co-financed by the Saxon State Government out of the State Budget approved by the Saxon State Parliament.
文摘Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instrument function,is measured in X-ray Thom-son scattering(XRTS)experiments,which allow the study of electronic structure properties at the microscopic level.Among the various ab initio methods,linear-response time-dependent density-functional theory(LR-TDDFT)is a key framework for simulating the DSF.The standard approach in LR-TDDFT for computing the DSF relies on the orbital representation.A significant drawback of this method is the unfavorable scaling of the number of required empty bands as the wavenumber increases,making LR-TDDFT impractical for modeling XRTS measurements over large energy scales,such as in backward scattering geometry.In this work,we consider and test an alternative approach to LR-TDDFT that employs the Liouville–Lanczos(LL)method for simulating the DSF of WDM.This approach does not require empty states and allows the DSF at large momentum transfer values and over a broad frequency range to be accessed.We compare the results obtained from the LL method with those from the solution of Dyson’s equation using the standard LR-TDDFT within the projector augmented-wave formalism for isochorically heated aluminum and warm dense hydrogen.Additionally,we utilize exact path integral Monte Carlo results for the imaginary-time density-density correlation function(ITCF)of warm dense hydrogen to rigorously benchmark the LL approach.We discuss the application of the LL method for calculating DSFs and ITCFs at different wavenumbers,the effects of pseudopotentials,and the role of Lorentzian smearing.The successful validation of the LL method under WDM conditions makes it a valuable addition to the ab initio simulation landscape,supporting experimental efforts and advancing WDM theory.
基金supported in part by the National Science Foundation of China(52371372)the Project of Science and Technology Commission of Shanghai Municipality,China(22JC1401400,21190780300)the 111 Project,China(D18003)
文摘Dear Editor,This letter focuses on the fact that small objects with few pixels disappear in feature maps with large receptive fields, as the network deepens, in object detection tasks. Therefore, the detection of dense small objects is challenging.
基金funded by the Joint Fund for Regional Innovation and Development of National Natural Science Foundation of China(U21A20143)the National Science Fund for Excellent Young Scholars(52322607)the Excellent Youth Foundation of Heilongjiang Scientific Committee(YQ2022E028)。
文摘Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based electrode exhibit multi-scale structural characteristics including macroscopic electrode morphologies,mesoscopic microcrystals and pores,and microscopic defects and dopants in the carbon basal plane.Therefore,the ordered combination of multi-scale structures of carbon electrode is crucial for achieving dense energy storage and high volumetric performance by leveraging the functions of various scale structu re.Considering that previous reviews have focused more on the discussion of specific scale structu re of carbon electrodes,this review takes a multi-scale perspective in which recent progresses regarding the structureperformance relationship,underlying mechanism and directional design of carbon-based multi-scale structures including carbon morphology,pore structure,carbon basal plane micro-environment and electrode technology on dense energy storage and volumetric property of supercapacitors are systematically discussed.We analyzed in detail the effects of the morphology,pore,and micro-environment of carbon electrode materials on ion dense storage,summarized the specific effects of different scale structures on volumetric property and recent research progress,and proposed the mutual influence and trade-off relationship between various scale structures.In addition,the challenges and outlooks for improving the dense storage and volumetric performance of carbon-based supercapacitors are analyzed,which can provide feasible technical reference and guidance for the design and manufacture of dense carbon-based electrode materials.
基金supported by the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology under Grant 2024yjrc64the National Key R&D Program of China under Grant 2018YFC1504102。
文摘The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velocity models are available for the LMS fault zone,high-resolution velocity models are lacking.Therefore,a dense array of 240 short-period seismometers was deployed around the central segment of the LMS fault zone for approximately 30 days to monitor earthquakes and characterize fine structures of the fault zone.Considering the large quantity of observed seismic data,the data processing workflow consisted of deep learning-based automatic earthquake detection,phase arrival picking,and association.Compared with the earthquake catalog released by the China Earthquake Administration,many more earthquakes were detected by the dense array.Double-difference seismic tomography was adopted to determine V_(p),V_(s),and V_(p)/V_(s)models as well as earthquake locations.The checkerboard test showed that the velocity models have spatial resolutions of approximately 5 km in the horizontal directions and 2 km at depth.To the west of the Yingxiu–Beichuan Fault(YBF),the Precambrian Pengguan complex,where most of earthquakes occurred,is characterized by high velocity and low V_(p)/V_(s)values.In comparison,to the east of the YBF,the Upper Paleozoic to Jurassic sediments,where few earthquakes occurred,show low velocity and high V_(p)/V_(s)values.Our results suggest that the earthquake activity in the LMS fault zone is controlled by the strength of the rock compositions.When the high-resolution velocity models were combined with the relocated earthquakes,we were also able to delineate the fault geometry for different faults in the LMS fault zone.
基金National Natural Science Foundation of China(Nos.42025702,52394251)。
文摘Currently,there is a lack of in-situ or model test results for cone penetration tests(CPTs)conducted in deep,dense sand layers under high overburden stresses,restricting the development of empirical relationships between CPT results and the characteristics of such deep,dense sand layers.This study addresses this gap by proposing an empirical relationship to predict the relative density of dense silica sand based on stress level and cone tip resistance.The relationship was developed through CPTs performed in a calibration chamber using dense sand specimens(with relative densities of 74%-91%)subjected to high stresses(under overburden stresses of 0.5-2.0 MPa)and numerical simulations employing the large deformation finite element method.The Arbitrary Lagrangian Eulerian method was used to regularly regenerate the mesh to prevent soil element distortion around the cone tip.Additionally,the modified Mohr-Coulomb model was integrated to capture the stress-strain behavior of dense silica sand under high stresses.A reasonable agreement was achieved between the numerical and experimental penetration profiles,which verifies the reliability of the numerical model.A sufficient number of parametric analyses were carried out,and then an empirical equation was proposed to establish the relationship between the relative density of dense sand,stress level and cone resistance.The empirical equation provides predictions with acceptable accuracy,as the discrepancies between the predicted and measured relative density values fall within±30%.
基金supported in part by the National Natural Science Foundation of China under Grant 62303090,U2330206in part by the Postdoctoral Science Foundation of China under Grant 2023M740516+1 种基金in part by the Natural Science Foundation of Sichuan Province under Grant 2024NSFSC1480in part by the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘Reliable electricity infrastructure is critical for modern society,highlighting the importance of securing the stability of fundamental power electronic systems.However,as such systems frequently involve high-current and high-voltage conditions,there is a greater likelihood of failures.Consequently,anomaly detection of power electronic systems holds great significance,which is a task that properly-designed neural networks can well undertake,as proven in various scenarios.Transformer-like networks are promising for such application,yet with its structure initially designed for different tasks,features extracted by beginning layers are often lost,decreasing detection performance.Also,such data-driven methods typically require sufficient anomalous data for training,which could be difficult to obtain in practice.Therefore,to improve feature utilization while achieving efficient unsupervised learning,a novel model,Densely-connected Decoder Transformer(DDformer),is proposed for unsupervised anomaly detection of power electronic systems in this paper.First,efficient labelfree training is achieved based on the concept of autoencoder with recursive-free output.An encoder-decoder structure with densely-connected decoder is then adopted,merging features from all encoder layers to avoid possible loss of mined features while reducing training difficulty.Both simulation and real-world experiments are conducted to validate the capabilities of DDformer,and the average FDR has surpassed baseline models,reaching 89.39%,93.91%,95.98%in different experiment setups respectively.
基金the National Natural Science Foundation of China(Grant No.52127815)the Hubei Provincial Natural Science Foundation of China(Grant No.2023AFA078).
文摘Shallow gas can cause many disasters,and it is reported in many marine engineering constructions.For this,it is imperative to understand the impact of gas on the mechanical behaviors of soil.This study investigated the influence of undrained triaxial compression tests on dense gassy sand commonly encountered in coastal areas.Triaxial tests were performed on specimens with saturations of 100%,99.8%,95.9%,and 92.7% under confining pressures of 50 kPa and 200 kPa by a self-developed multipurpose integrated triaxial apparatus(MITA)for gassy soil.The results are presented in terms of monotonic stress‒strain behavior,volumetric behavior,shear strength,and excess pore water pressure(EPWP).The occurrence of gas bubbles has different effects on loose and dense sands,augmenting the undrained shear strength of loose sand while concurrently diminishing that of dense sand.The deviatoric stress of dense sand increases during shear shrinkage,which is similar to the characteristics of loose sand under the influence of gas bubbles.However,following sand dilation,the effect of gas bubbles on deviatoric stress manifests in an antithetical manner.With elevated gas content,the shear strength of dense sand decreases,accompanied by a deceleration in the development of EPWP and a notable increase in volumetric changes.To this end,a microscopic explanation concerning the deformation and evolution of gas bubbles within sand during the shear process was presented to reveal the macroscopic laws governing the undrained shear attributes of dense gassy sand.
基金supported by the National Natural Science Foundation of China(No.U2239206)Selfinitiated Project of the Institute of Geophysics of the China Earthquake Administration(JY2022Z48)+1 种基金the Dedicated Fundamental Research Funds of the Institute of Geophysics of the China Earthquake Administration(No.DQJB23X16)the Science and Technology Support Project of Guizhou Province(QKHZC[2022]General 238).
文摘The aftershocks of the 1975 M_(S)7.3 Haicheng and 1999 M_(S)5.4 Xiuyan earthquakes have persisted for a long time.The ChinArray-III dense stations,deployed in eastern North China from 2018 to 2020,increased seismic monitoring capability in the Haicheng-Xiuyan region,which can facilitate the construction of high-precision earthquake catalogs to better clarify the fault structures and seismogenic mechanisms of the two earthquakes.In this study,we selected 15 permanent stations and 37 ChinArray-III stations within 150 km of the epicenter of the Haicheng Earthquake.Next,we used deep learning methods to pick P-and S-wave phases from continuous waveforms recorded at these stations from January 2018 to July 2020.Based on these picks,we constructed an automatic earthquake catalog of the Haicheng-Xiuyan region.Compared with the routine manual catalog by China Earthquake Networks Center(CENC),our catalog contains 9.7 times more seismic events,including 98.3%of the seismic events in the CENC catalog,and has a lower magnitude of completeness(M_(c)=1.1 vs M_(c)=1.8 for the CENC catalog).The relocated events indicate that the strike of the Haichenghe-Dayanghe fault varies considerably from northwest to southeast,indicating that the fault bends slightly around the hypocenter of the 1975 M_(S)7.3 Haicheng earthquake which may act as a channel for fluid migration.The weak seismicity in the area between Haicheng and Xiuyan indicates that the fault section may be locked.Furthermore,the 1999 M_(S)5.4 Xiuyan earthquake and its aftershock sequence occurred on the Kangjialing fault and its ENE-trending conjugate fault,and the intersection of the two faults coincides with the source areas of the 1999 M_(S)5.4 and 2000 M_(S)5.1 Xiuyan earthquakes.Therefore,the Xiuyan earthquake sequence may be controlled by the Kangjialing fault and its conjugate fault.This study shows that the automatic earthquake catalog,obtained by deep learning methods and dense seismic array,can provide valuable information for fault structures and the seismogenic mechanisms of moderate-to-strong earthquakes.
基金Projects(52104143,52109135,52374099)supported by the National Natural Science Foundation of ChinaProject(2025YFHZ0323)supported by the Natural Science Foundation of Sichuan Province,China。
文摘The evolution of cracks in shale directly affects the efficient production of shale gas.However,there is a lack of research on the characteristics of crack initiation in deep dense shale under different stress conditions.In this work,considering the different combinations of confining pressure and bedding plane inclination angle(α),biaxial mechanical loading experiments were conducted on shale containing circular holes.The research results indicate that the confining pressure and inclination angle of the bedding planes significantly influence the failure patterns of shale containing circular holes.The instability of shale containing circular holes can be classified into five types:tensile failure along the bedding planes,tensile failure through the bedding planes,shear slip along the bedding planes,shear failure through the bedding planes,and block instability failure.Furthermore,the evolution of strain and stress fields around the circular holes was found to be the fundamental cause of variations in the initiation characteristics and locations of shale cracks.The crack initiation criterion for shale containing circular hole was established,providing a new method for evaluating the trajectory of shale hole wall fractures.This study holds significant importance for evaluating the evolution and stability of fracture networks within shale reservoirs.
基金supported by National Natural Science Foundation of China(62271096,U20A20157)Natural Science Foundation of Chongqing,China(CSTB2023NSCQ-LZX0134)+3 种基金University Innovation Research Group of Chongqing(CXQT20017)Youth Innovation Group Support Program of ICE Discipline of CQUPT(SCIE-QN-2022-04)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202300632)the Chongqing Postdoctoral Special Funding Project(2022CQBSHTB2057).
文摘Aiming at the problem of mobile data traffic surge in 5G networks,this paper proposes an effective solution combining massive multiple-input multiple-output techniques with Ultra-Dense Network(UDN)and focuses on solving the resulting challenge of increased energy consumption.A base station control algorithm based on Multi-Agent Proximity Policy Optimization(MAPPO)is designed.In the constructed 5G UDN model,each base station is considered as an agent,and the MAPPO algorithm enables inter-base station collaboration and interference management to optimize the network performance.To reduce the extra power consumption due to frequent sleep mode switching of base stations,a sleep mode switching decision algorithm is proposed.The algorithm reduces unnecessary power consumption by evaluating the network state similarity and intelligently adjusting the agent’s action strategy.Simulation results show that the proposed algorithm reduces the power consumption by 24.61% compared to the no-sleep strategy and further reduces the power consumption by 5.36% compared to the traditional MAPPO algorithm under the premise of guaranteeing the quality of service of users.
基金financially supported by the National Natural Science Foundation of China(No.51762021)the Natural Science Foundation of Jiangxi province(Nos.20224ACB204008,20242BAB25223,and 20242BAB25248)the Special Funding Program for Graduate Student Innovation of Jiangxi Province(No.YC2024-S594)。
文摘Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages of amorphous materials to optimize the interfacial structure for efficient Na^(+)storage.Herein,the dense homologous amorphous/crystalline heterointerfaces are in situ achieved in N-doped carbon nanobundles via self-polymerization and precise nitriding(Mo–N/Mo_(2)N@C).The amorphous Mo–N rich in unsaturated vacancy defects provides abundant active sites with isotropic ion-transport channels,and can effectively alleviate structural stress from crystalline Mo_(2)N.Meanwhile,the conductive Mo_(2)N can facilitate effective electron transfer,augmented further by the carbon encapsulation.Theoretical calculations reveal that the dense heterointerfaces can optimize the electronic structure and shift the d-p orbital centers of Mo and N upward,thereby enhancing the adsorption and mobility of Na^(+),and ultimately improving the charge transport and storage efficiency of the electrode.The Mo–N/Mo_(2)N@C as an anode delivers a 46.9%increase in reversible capacity over Mo_(2)N@C,reaching 461.1 m Ah.g^(–1)at 0.1 A.g^(–1),along with improved rate capability and cycling stability,underlining its practical utility.These results suggest that the homologous interfacial coupling can boost the storage properties of nitrides,providing a valuable reference for improving the properties of electrodes with low theoretical capacities.
