The admission control scheme is investigated for a FIFO self-similar queuing system with Quality of Service (QoS) performance guarantees. Since the self-similar queuing system performance analysis is often carried out...The admission control scheme is investigated for a FIFO self-similar queuing system with Quality of Service (QoS) performance guarantees. Since the self-similar queuing system performance analysis is often carried out under the condition of infinite buffer, it is difficult to deduce the upper boundary of buffer overflow probability. To overcome this shortcoming, a simple overflow condition is proposed, which defines a buffer overflow occurrence whenever the arrival rate exceeds the service rate. The analytic formula for the buffer overflow probability upper boundary is easily obtained under this condition. The required bandwidth upper boundary with long-range dependence input and determined overflow probability is then derived from this formula. Based on the above analytic formulas, the upper boundaries of the admission control regions for homogeneous and heterogeneous long-range dependence traffic sources are separately obtained. Finally, an effective admission control scheme for long-range dependence input is proposed. Simulation studies with real traffic have confirmed the validity of these results.展开更多
Forest biological disasters(FBD) seriously impact energy flow and material cycling in forest ecosystems,while the underlying causes of FBD are complex. These disasters involve large areas and cause tremendous losses. ...Forest biological disasters(FBD) seriously impact energy flow and material cycling in forest ecosystems,while the underlying causes of FBD are complex. These disasters involve large areas and cause tremendous losses. As a result,the occurrence of FBDs in China( CFBD) threatens the country's ability to realize its strategic target of increasing both forested area(40 million ha) and forest volume(1.3 billion m^3) from 2005 to 2020. Collectively,China has officially named this effort to increase forest area and volume the "Two Increases" as national goals related to forestry. Based on Hurst index analysis from fractal theory,we analyzed the time series of the occurrence area and related data of FBDs from 1950 to 2007 to quantitatively determine the patterns of the macro occurrence of FBDs in China. Results indicates that,the time series of( CFBD) areas is fractal( self-affinity fractal dimension D = 1. 3548),the fluctuation of( CFBD) areas is positively correlated( auto-correlation coefficient C = 0. 2170),and the occurrence of the time series of( CFBD) is long-range dependent( Hurst index H =0. 6416),showing considerably strong trend of increases in FBDC area. Three different methods were further carried out on the original time series,and its two surrogate series generated by function surrogate in library t series,and function Surrogate Data in library in Wavelet software R,so as to analyze the reliability of Hurst indexes. The results showed that the Hurst indices calculated using different estimation methods were greater than 0. 5,ranging from 0. 64 to 0. 97,which indicated that the change of occurrence area data of FBDs was positively autocorrelated.The long-range dependence in forest biological disasters in China is obvious,and the spatial extent of FBDs tended to increase during this study period indicating this trend should be expected to persistent and worsen in the future.展开更多
In the paper, using Levy processes subordinated by 'asymptotically self-similar activity time' pro- cesses with long-range dependence, we set up new asset pricing models. Using the different construction for gamma ...In the paper, using Levy processes subordinated by 'asymptotically self-similar activity time' pro- cesses with long-range dependence, we set up new asset pricing models. Using the different construction for gamma (F) based 'asymptotically self-similar activity time' processes with long-range dependence from Fin- lay and Seneta (2006) we extend the constructions for inverse-gamma and gamma based 'asymptotically self- similar activity time' processes with integer-vMued parameters and long-range dependence in Heyde and Leo- nenko (2005) and Finlay and Seneta (2006) to noninteger-valued parameters.展开更多
In the field of intelligent air combat,real-time and accurate recognition of within-visual-range(WVR)maneuver actions serves as the foundational cornerstone for constructing autonomous decision-making systems.However,...In the field of intelligent air combat,real-time and accurate recognition of within-visual-range(WVR)maneuver actions serves as the foundational cornerstone for constructing autonomous decision-making systems.However,existing methods face two major challenges:traditional feature engineering suffers from insufficient effective dimensionality in the feature space due to kinematic coupling,making it difficult to distinguish essential differences between maneuvers,while end-to-end deep learning models lack controllability in implicit feature learning and fail to model high-order long-range temporal dependencies.This paper proposes a trajectory feature pre-extraction method based on a Long-range Masked Autoencoder(LMAE),incorporating three key innovations:(1)Random Fragment High-ratio Masking(RFH-Mask),which enforces the model to learn long-range temporal correlations by masking 80%of trajectory data while retaining continuous fragments;(2)Kalman Filter-Guided Objective Function(KFG-OF),integrating trajectory continuity constraints to align the feature space with kinematic principles;and(3)Two-stage Decoupled Architecture,enabling efficient and controllable feature learning through unsupervised pre-training and frozen-feature transfer.Experimental results demonstrate that LMAE significantly improves the average recognition accuracy for 20-class maneuvers compared to traditional end-to-end models,while significantly accelerating convergence speed.The contributions of this work lie in:introducing high-masking-rate autoencoders into low-informationdensity trajectory analysis,proposing a feature engineering framework with enhanced controllability and efficiency,and providing a novel technical pathway for intelligent air combat decision-making systems.展开更多
The high-resolution photoassociation spectrum of the ultracold cesium molecular 0+ state below the 6S1/2 + 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is obs...The high-resolution photoassociation spectrum of the ultracold cesium molecular 0+ state below the 6S1/2 + 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is observed from the depen dence of the trap-loss probability on the photoassociation laser intensity. The corresponding resonant line width is also demonstrated to increase linearly with increasing photoassociation laser intensity. Our experimental data have good con sistency with the theoretical saturation model of Bohn and Julienne [Bohn J L and Julienne P S 1999 Phys. Rev. A 60 1].展开更多
Sluggish sulfur conversion kinetics pose an ongoing challenge in lithium-sulfur batteries(LSBs).Here,we present a solution through far-reaching long-range electronic regulation(LRER)on single-atom active sites.N-doped...Sluggish sulfur conversion kinetics pose an ongoing challenge in lithium-sulfur batteries(LSBs).Here,we present a solution through far-reaching long-range electronic regulation(LRER)on single-atom active sites.N-doped carbons(Co-NC)are implanted with densely-distributed Co single atoms,and supported on Ti_(3)C_(2)T_(x)MXene substrates to assemble 3D Co-NC/MXene catalyst.MXene effectively mediates interlayer charge transfer(~0.70|e|)contrasted with popular carbon materials(~0.06|e|)to produce LRER through surrounding carbon atoms.The synergy of LRER with near-range electronic regulation(NRER)tunes electronic structures,and enhances heterostructural stability,thus provoking desirous catalytic kinetics of Co single atoms in sulfur reduction.Thereby,the Co-NC/MXene/S cathodes exhibit impressive rate performance and excellent cycling stability(only 0.015%capacity decay per cycle over 600 cycles at 4 C)in LSBs,surpassing state-of-the-art sulfur cathodes.This work reveals the importance of LRER for improved catalysis,and provides new guidance to tailor heterostructures to achieve high-efficient catalysts in various process.展开更多
Catalysts with asymmetric coordination exhibit excellent electrocatalytic activity due to changes in the active sites,which affect the arrangement of reactants and catalytic activity/selectivity.Hence,the exploration ...Catalysts with asymmetric coordination exhibit excellent electrocatalytic activity due to changes in the active sites,which affect the arrangement of reactants and catalytic activity/selectivity.Hence,the exploration of the inherent characteristics of active sites within diverse coordination environments holds great significance for the experimental design of catalytic structures.Single-atom catalysts(SACs)characterized by high coordination with four carbons(26 candidates)and low coordination with dinitrogen(27candidates)are constructed using nitrogen-doped graphdiyne derivatives(NGDY)as the substrate.Additionally,5 species of dual-atom catalysts(DACs)with coexistence of both high and low coordination sites are also developed and their nitrogen reduction reaction(NRR)activities are systematically investigated by density functional theory.The results indicate that metals with low coordination exhibit superior catalytic performance,such as Mo^(L)-NGDY(U_(L)=-0.30 V)and Nb^(L)-NGDY(U_(L)=-0.32 V).Furthermore,machine learning(ML)methods have deeply analyzed and elucidated the primary intrinsic characteristics that influence catalytic performance.These results not only unveil the underlying mechanisms behind the exceptional catalytic performance exhibited by low-coordination metal atoms,but also provide relevant and significant descriptors.More importantly,based on an investigation of the catalytic activity of a series of DACs,the“buffer and low-coordination accumulate”asymmetric coordination mechanism is proposed to unveil the long-range interactions between low and high coordination atoms.Due to this remote communication,MoNb-NGDY(U_(L)=-0.09/-0.37 V)exhibits the best NRR activity.This mechanism provides valuable insights into the origin of long-range bipartite interactions and inspires the design and synthesis of NRR catalysts with different coordination environments.展开更多
A Hamiltonian mean-field model with long-range four-body interactions is proposed.The model describes a long-range mean-field system in which N unit-mass particles move on a unit circle.Each particleθi interacts with...A Hamiltonian mean-field model with long-range four-body interactions is proposed.The model describes a long-range mean-field system in which N unit-mass particles move on a unit circle.Each particleθi interacts with any three other particles through an infinite-range cosine potential with an attractive interaction(ε>0).By applying a method that remaps the average phase of global particle pairs onto a new unit circle,and using the saddle-point technique,the partition function is solved analytically after introducing four-body interactions,yielding expressions for the free energy f and the energy per particle U.These results were further validated through numerical simulations.The results show that the system undergoes a second-order phase transition at the critical energy Uc.Specifically,the critical energy corresponds to U_(c)=0.32 when the coupling constantε=5,and U_(c)=0.63 whenε=10.Finally,we calculated the system’s largest Lyapunov exponentλand kinetic energy fluctuationsΣthrough numerical simulations.It is found that the peak of the largest Lyapunov exponentλoccurs slightly below the critical energy Uc,which is consistent with the point of maximum kinetic energy fluctuationsΣ.And there is a scaling law ofΣ/N^(1/2)∝λbetween them.展开更多
In this study,we performed a systematic analysis of the multiplicity dependence of hadron production at mid-rapidity(|y|<0.5),ranging from the light to the charm sector in proton-proton(pp)collisions at√s=13 TeV.T...In this study,we performed a systematic analysis of the multiplicity dependence of hadron production at mid-rapidity(|y|<0.5),ranging from the light to the charm sector in proton-proton(pp)collisions at√s=13 TeV.This study used a multi-phase transport(AMPT)model coupled with PYTHIA8 initial conditions.We investigated the baryon-to-meson and the strange-to-non-strange meson ratios varying with the charged particle density.By tuning the coalescence parameters,the AMPT model provides a reasonable description of the experimental data for the inclusive production of both light and charm hadrons,comparable to the string fragmentation model calculations with color reconnection effects.Additionally,we analyzed the relative production of hadrons by examining the self-normalized particle ratios as a function of the charged hadron density.Our findings suggest that parton evolution effects and the coalescence hadronization process in the AMPT model result in a strong flavor hierarchy in the multiplicity dependence of the baryon-to-meson ratio.Furthermore,our investigation of the p_(T) differential double ratio of the baryon-to-meson fraction between high-and low-multiplicity events revealed distinct modifications to the flavor associated baryon-to-meson ratio p_(T) shape in high-multiplicity events when comparing the coalescence hadronization model to the color reconnection model.These observations highlight the importance of understanding the hadronization process in high-energy pp collisions through comprehensive multiplicity-dependent multi-flavor analysis.展开更多
We investigate the parity-time(PT)symmetry-breaking quantum phase transition in a one-dimensional(1D)bosonic lattice featuring cavity-mediated long-range interactions and spatially staggered dissipation.By mapping the...We investigate the parity-time(PT)symmetry-breaking quantum phase transition in a one-dimensional(1D)bosonic lattice featuring cavity-mediated long-range interactions and spatially staggered dissipation.By mapping the system to an effective spin chain under the constraints of hard-core bosons and integrating the mean-field decoupling approach with biorthogonal basis formalism,we derive a self-consistency equation.Numerical simulation results validate that the derived equation quantitatively captures thePT-symmetry order parameter’s phase diagram.Our findings reveal that coherent hopping maintainsPTsymmetry through quantum fluctuations.Conversely,cavity-engineered long-range interactions,in synergy with staggered dissipation,act in opposition to drive symmetry breaking.This competitive interplay can inspire further exploration of tunable quantum phase transitions in non-Hermitian systems.展开更多
Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,...Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,Sub1 and Dro1(Δbp:10 Mb),as well as Sub1 and TPP7(Δbp:6 Mb)were identified to exhibit long-range linkage disequilibrium(LRLD).Meta-QTL analysis further revealed that Sub1 and TPP7 co-segregated for tolerance to submergence at the germination and seedling stages.Based on this,we hypothesized that LRLD might influence plant responses to consecutive stresses.To test this hypothesis,we developed a structured recombinant inbred line population from a cross between Bhalum 2 and Nagina 22,with alleles(Sub1 and TPP7)in linkage equilibrium.Mendelian randomization analysis validated that the parental alleles,rather than the recombinant alleles of Sub1 and TPP7,significantly influenced 13 out of 41 traits under consecutive stress conditions.Additionally,16 minor additive effect QTLs were detected between the genomic regions,spanning Sub1 and TPP7 for various traits.A single allele difference between these genomic regions enhanced crown root number,root dry weight,and specific root area by 11.45%,15.69%,and 33.15%,respectively,under flooded germination conditions.Candidate gene analysis identified WAK79 and MRLK59 as regulators of stress responses during flooded germination,recovery,and subsequent water deficit conditions.These findings highlight the critical role of parental allele combinations and genomic regions between Sub1 and TPP7 in regulating the stress responses under consecutive stresses.Favourable haplotypes derived from these alleles can be utilized to improve stress resilience in direct-seeded rice.展开更多
OBJECTIVE:To observe the effect of different acupuncture frequencies on the abstinence rate which could be used as a reference for optimizing acupuncture cessation programs.METHODS:From July 2018 to June 2022,a total ...OBJECTIVE:To observe the effect of different acupuncture frequencies on the abstinence rate which could be used as a reference for optimizing acupuncture cessation programs.METHODS:From July 2018 to June 2022,a total of 220 smokers were recruited based on inclusion criteria and randomly divided into the high-frequency acupuncture group(HF group,n=110):5 times a week from the 1st to the 4th week,from weeks 5 to 8,three times a week and the low-frequency acupuncture group(LF group,n=110):3 times a week from the 1st to the 4th week,from weeks 5 to 8,twice a week,then treated for 8 weeks and followup at 1 month in Beijing.RESULTS:In total,162 subjects completed the whole study with a drop-out rate of 20.45%.The expiratory CO point abstinence rate was HF group 53/110(48.18%)vs LF group 41/110(37.27%)in Week 8(P=0.102)and HF group 46/110(41.82%)vs LF group 45/110(40.91%)in Week 12(P=0.891)and the HF acupuncture and LF acupuncture were nearly equal in the 8-week abstinence rate.In addition,both HF and LF acupuncture significantly reduced Fagerstr?m test for nicotine dependence scale(FTND)scores(P<0.05),Minnesota nicotine withdrawal scale(MNWS)scores(P<0.05),and Brief Questionnaire of Smoking Urges scale(QSU-Brief)scores(P<0.05),but HF acupuncture showed some superiority over LF acupuncture in relieving patients'smoking cravings(P<0.05).CONCLUSIONS:The study initially showed that both high-frequency acupuncture and low-frequency acupuncture treatment were safe and effective on smoking cessation for 8 weeks,but high-frequency acupuncture was advantageous in reducing smoking cravings.More accurate acupuncture frequency needs to be validated through larger clinical studies to optimize acupuncture smoking cessation programs.展开更多
Electrocatalysis has been investigated as a promising strategy to utilize green electricity to produce renewable fuels,valuable chemicals,and treat pollutants.Electrode kinetic analysis is a potent technique in interr...Electrocatalysis has been investigated as a promising strategy to utilize green electricity to produce renewable fuels,valuable chemicals,and treat pollutants.Electrode kinetic analysis is a potent technique in interrogating reaction mechanisms and evaluating the electrocatalysts.Electron transfer(ET)and proton‐coupled electron transfer(PCET)processes are widely present in reaction networks of electrocatalysis.pH dependence of the kinetics is frequently employed to evaluate whether an elementary step involves proton participation,which is determined by both the reversibility and the specific reactants of electrode reactions.In this article,we discuss the pH dependence of two widely used formulations of the Butler–Volmer kinetics for a model PCET step and highlight a potential pitfall in kinetic analysis.This work aims to provide guiding principles for distinguishing ET and PCET steps via kinetic measurements in electrolytes in a broad range pH values.展开更多
Nanomaterials have garnered recognition for their notable surface effects and demonstration of superior mechanical properties.Previous studies on the surface effects of nanomaterials,employing the finite element metho...Nanomaterials have garnered recognition for their notable surface effects and demonstration of superior mechanical properties.Previous studies on the surface effects of nanomaterials,employing the finite element method,often relied on simplified twodimensional models due to theoretical complexities.Consequently,these simplified models inadequately represent the mechanical properties of nanomaterials and fail to capture the substantial impact of surface effects,particularly the curvature dependence of nanosurfaces.This study applies the principle of minimum energy and leverages the Steigmann-Ogden surface theory of nanomaterials to formulate a novel finite element surface element that comprehensively accounts for surface effects.We conducted an analysis of the stress distribution and deformation characteristics of four typical 2D and 3D nanomaterial models.The accuracy of the developed surface element and finite element calculation method was verified through comparison with established references.The resulting finite element model provides a robust and compelling scientific approach for accurately predicting the mechanical performance of nanomaterials.展开更多
Partial phase transformation in NiTi-based refrigerants usually enables efficient and durable elastocaloric cooling,but its thermomechanical behavior with varying temperatures remains unclear.Keeping this in view,the ...Partial phase transformation in NiTi-based refrigerants usually enables efficient and durable elastocaloric cooling,but its thermomechanical behavior with varying temperatures remains unclear.Keeping this in view,the elastocaloric effect of NiTi under incomplete transformation across 15-100℃ is investigated and a superelastic deformation window between 25 and 85℃ is identified.Synchronous infrared thermography and digital image correlation,and an innovative macro-micro phase-field model are employed to examine martensitic transformation and elastocaloric properties of NiTi within the superelastic window.Experimental and simulated results consistently reveal that the spatiotemporal thermal profiles correlate with Lüders strain band evolution.As superelastic deformation temperature increases,strain localization intensifies,with Lüders bands favoring an inward strain growth over an outward expansion,resulting in a smaller yet more deformed martensitic transformation zone.The aggravated strain inhomogeneity makes the local endothermic undercooling tested at 85℃ up to about twice(−30.05℃)that at 25℃(−15.32℃),boosting the global cooling capacity by 65%,despite constant strain.The seeming contradiction between the larger elastocaloric effect and the narrower apparent martensitic transformation zone is elucidated by recourse to the simulations.It is found that the martensitic transformation within the Lüders bands is incomplete,proceeding in a macroscopically uniform but microscopically heterogeneous manner.Elevated temperatures within the superelastic window increase the transformed volume fraction and enhance martensitic transformation,thereby strengthening the global caloric effect.The work sheds light on the interplay between partial martensitic transformation and thermal behavior in NiTi under varying superelastic deformation temperatures,providing insights for advanced elastocaloric cooling applications.展开更多
Objective:To evaluate the global liter-ature output on the relationship between brain-derived neurotrophic factor(BDNF)and cognitive function in al-cohol dependence syndrome using bibliometric methods and explore the ...Objective:To evaluate the global liter-ature output on the relationship between brain-derived neurotrophic factor(BDNF)and cognitive function in al-cohol dependence syndrome using bibliometric methods and explore the status and trends in this field.Method:The literature on the application of BDNF in cognitive impairment caused by alcohol dependence syndrome published from 1995 to 2023 were retrieved from Web of Science,and the relevant information(publication characteristics,country and institution,author,number of publications,citation,journal and research field,corresponding author,key words,etc.)was recorded.The bibliometrix R package was used for quantitative and qualitative analysis of publication output and author contributions.Result:A total of 99 articles were included.The overall number of publications in this field has increased over time.The countries and institutions that contributed the most to the field were the United States and the Academy of Medical Sciences of Iranian universities,respectively.Most of the authors were from the United States,followed by Spain,China,and Iran.Ceccanti M,Fiore M were the most productive authors.Publications with Ceccanti M had the highest h-index.The most cited reference author is Haenninen H(227 citations),and the number one published journal is Alcohol.Most articles were published in 2020(n=12)and 2022(n=11),followed by 2019 and 2021(n=10).The corresponding author has the largest number of publications from the United States,and more publications from a single country tend to have more cooperation from other countries.BDNF and alcohol appeared more frequently in various keyword clouds.However,significant differences remained in the author keyword cloud,keyword plus word cloud,and paper topic word cloud.Conclusion:BDNF has great potential in the application of cognitive dysfunction caused by alcohol dependence syndrome.Bibliometric methods and data visualization techniques can help understand the current state of research progress and enable relevant scholars and practitioners to predict the development trends in this field.展开更多
In the field of data-driven bearing fault diagnosis,convolutional neural network(CNN)has been widely researched and applied due to its superior feature extraction and classification ability.However,the convolutional o...In the field of data-driven bearing fault diagnosis,convolutional neural network(CNN)has been widely researched and applied due to its superior feature extraction and classification ability.However,the convolutional operation could only process a local neighborhood at a time and thus lack the ability of capturing long-range dependencies.Therefore,building an efficient learning method for long-range dependencies is crucial to comprehend and express signal features considering that the vibration signals obtained in a real industrial environment always have strong instability,periodicity,and temporal correlation.This paper introduces nonlocal mean to the CNN and presents a 1D nonlocal block(1D-NLB)to extract long-range dependencies.The 1D-NLB computes the response at a position as a weighted average value of the features at all positions.Based on it,we propose a nonlocal 1D convolutional neural network(NL-1DCNN)aiming at rolling bearing fault diagnosis.Furthermore,the 1D-NLB could be simply plugged into most existing deep learning architecture to improve their fault diagnosis ability.Under multiple noise conditions,the 1D-NLB improves the performance of the CNN on the wheelset bearing data set of high-speed train and the Case Western Reserve University bearing data set.The experiment results show that the NL-1DCNN exhibits superior results compared with six state-of-the-art fault diagnosis methods.展开更多
The post-fledging period, extending from fledging to independence, is a crucial life stage characterized by high mortality due to fledglings' limited mobility and inexperience. During this stage, fledglings gradua...The post-fledging period, extending from fledging to independence, is a crucial life stage characterized by high mortality due to fledglings' limited mobility and inexperience. During this stage, fledglings gradually increase their mobility, leave their parents, disperse from their natal site, and respond to the challenges of new environments. Characterizing these post-fledging movements and space use is essential for understanding juvenile survival strategies and devising targeted conservation measures. The Crested Ibis (Nipponia nippon), an endangered species and a highly protected animals at the national level in China, has seen limited research on its post-fledging movements and space use. From 2015 to 2023, we utilized biologgers, combined with field surveys, to study the movement and space use characteristics of 37 fledglings in Hanzhong City, Shaanxi Province, China, over a two-month post-fledging period. We quantified changes in activity levels (based on overall dynamic body acceleration), independence timing, onset of post-fledging dispersal, habitat selection, and daily activity rhythms after independence. Our results revealed individuals began independent living 26.23 ± 2.34 days post-fledging and onset of dispersal at 25.58 ± 2.33 days, with a range area at the natal of 2.08 ± 0.56 km^(2). The initial 30 days post-fledging are characterized as an ontogenetic phase marked by a rapid increase in body activity level. Fledglings preferred paddy fields during the independent period rather than the forests they relied on before independence. Interestingly, the daily activity rhythm, particularly foraging behavior, peaked at noon—contrasting with the expected morning and evening activity peaks—likely as an adaptation to avoid periods of peak human activity. Additionally, drowning, collisions, and predation in paddy fields are noteworthy causes of fledgling mortality. Consequently, we recommend protecting a 2-km^(2) area around the nest site for at least two-month post-fledging, implementing safety measures around power lines and cesspools. Additionally, reducing human disturbances near foraging habitats and expanding space within paddy fields would help mitigate survival pressures on fledglings.展开更多
The thickness dependence of linearly polarized light-induced momentum anisotropy and the inverse spin Hall effect(PISHE)in topological insulator(TI)Bi_(2)Te_(3)films has been investigated.A significant enhancement of ...The thickness dependence of linearly polarized light-induced momentum anisotropy and the inverse spin Hall effect(PISHE)in topological insulator(TI)Bi_(2)Te_(3)films has been investigated.A significant enhancement of the PISHE signal is observed in the 12-quintuple-layer(QL)Bi_(2)Te_(3)film compared with that of the 3-and 5-QL samples,whereas a minimal value of photoinduced momentum anisotropy is found in the 12-QL sample.The photoinduced momentum anisotropy and the PISHE in Bi_(2)Te_(3)films are more than three and two orders of magnitude larger than those in Bi2Se3 films grown on SrTiO_(3)substrates,respectively.The 3-QL sample exhibits a sinusoidal dependence of the PISHE current on the light spot position,while the 5-QL and 12-QL samples show aW-shaped dependence,which arises from the different angles between the coordinate axis x and the in-plane crystallographic axis of the Bi_(2)Te_(3)films.Our findings demonstrate the critical role of film thickness in modulating both the photoinduced momentum anisotropy and the PISHE current,thereby suggesting a thickness-engineering strategy for designing novel optoelectronic devices based on TIs.展开更多
Based on the EAM potential, a molecular dynamics study on the tensile properties of ultrathin nickel nanowires in the (100〉 orientation with diameters of 3.94, 4.95 and 5.99 nm was presented at different temperature...Based on the EAM potential, a molecular dynamics study on the tensile properties of ultrathin nickel nanowires in the (100〉 orientation with diameters of 3.94, 4.95 and 5.99 nm was presented at different temperatures and strain rates. The temperature and strain rate dependences of tensile properties were investigated. The simulation results show that the elastic modulus and the yield strength are gradually decreasing with the increase of temperature, while with the increase of the strain rate, the stress--strain curves fluctuate more intensely and the ultrathin nickel nanowires rupture at one smaller and smaller strain. At an ideal temperature of 0.01 K, the yield strength of the nanowires drops rapidly with the increase of strain rate, and at other temperatures the strain rate has a little influence on the elastic modulus and the yield strength. Finally, the effects of size on the tensile properties of ultrathin nickel nanowires were briefly discussed.展开更多
文摘The admission control scheme is investigated for a FIFO self-similar queuing system with Quality of Service (QoS) performance guarantees. Since the self-similar queuing system performance analysis is often carried out under the condition of infinite buffer, it is difficult to deduce the upper boundary of buffer overflow probability. To overcome this shortcoming, a simple overflow condition is proposed, which defines a buffer overflow occurrence whenever the arrival rate exceeds the service rate. The analytic formula for the buffer overflow probability upper boundary is easily obtained under this condition. The required bandwidth upper boundary with long-range dependence input and determined overflow probability is then derived from this formula. Based on the above analytic formulas, the upper boundaries of the admission control regions for homogeneous and heterogeneous long-range dependence traffic sources are separately obtained. Finally, an effective admission control scheme for long-range dependence input is proposed. Simulation studies with real traffic have confirmed the validity of these results.
基金Supported by the Project "Researches of Southern China’s Forestry Strategy"(2013-R17) and "Improvement of the Forest Resources Monitoring System of China"(2011-R03) Funded by the State Forestry Administration of China
文摘Forest biological disasters(FBD) seriously impact energy flow and material cycling in forest ecosystems,while the underlying causes of FBD are complex. These disasters involve large areas and cause tremendous losses. As a result,the occurrence of FBDs in China( CFBD) threatens the country's ability to realize its strategic target of increasing both forested area(40 million ha) and forest volume(1.3 billion m^3) from 2005 to 2020. Collectively,China has officially named this effort to increase forest area and volume the "Two Increases" as national goals related to forestry. Based on Hurst index analysis from fractal theory,we analyzed the time series of the occurrence area and related data of FBDs from 1950 to 2007 to quantitatively determine the patterns of the macro occurrence of FBDs in China. Results indicates that,the time series of( CFBD) areas is fractal( self-affinity fractal dimension D = 1. 3548),the fluctuation of( CFBD) areas is positively correlated( auto-correlation coefficient C = 0. 2170),and the occurrence of the time series of( CFBD) is long-range dependent( Hurst index H =0. 6416),showing considerably strong trend of increases in FBDC area. Three different methods were further carried out on the original time series,and its two surrogate series generated by function surrogate in library t series,and function Surrogate Data in library in Wavelet software R,so as to analyze the reliability of Hurst indexes. The results showed that the Hurst indices calculated using different estimation methods were greater than 0. 5,ranging from 0. 64 to 0. 97,which indicated that the change of occurrence area data of FBDs was positively autocorrelated.The long-range dependence in forest biological disasters in China is obvious,and the spatial extent of FBDs tended to increase during this study period indicating this trend should be expected to persistent and worsen in the future.
基金supported by National Natural Science Foundation of China(Grant No.71271042)the Plan of Jiangsu Specially-Appointed Professors,the Jiangsu Hi-Level Innovative and Entrepreneurship Talent Introduction Plan and Major Program of Key Research Center in Financial Risk Management of Jiangsu Universities Philosophy Social Sciences(Grant No.2012JDXM009)
文摘In the paper, using Levy processes subordinated by 'asymptotically self-similar activity time' pro- cesses with long-range dependence, we set up new asset pricing models. Using the different construction for gamma (F) based 'asymptotically self-similar activity time' processes with long-range dependence from Fin- lay and Seneta (2006) we extend the constructions for inverse-gamma and gamma based 'asymptotically self- similar activity time' processes with integer-vMued parameters and long-range dependence in Heyde and Leo- nenko (2005) and Finlay and Seneta (2006) to noninteger-valued parameters.
文摘In the field of intelligent air combat,real-time and accurate recognition of within-visual-range(WVR)maneuver actions serves as the foundational cornerstone for constructing autonomous decision-making systems.However,existing methods face two major challenges:traditional feature engineering suffers from insufficient effective dimensionality in the feature space due to kinematic coupling,making it difficult to distinguish essential differences between maneuvers,while end-to-end deep learning models lack controllability in implicit feature learning and fail to model high-order long-range temporal dependencies.This paper proposes a trajectory feature pre-extraction method based on a Long-range Masked Autoencoder(LMAE),incorporating three key innovations:(1)Random Fragment High-ratio Masking(RFH-Mask),which enforces the model to learn long-range temporal correlations by masking 80%of trajectory data while retaining continuous fragments;(2)Kalman Filter-Guided Objective Function(KFG-OF),integrating trajectory continuity constraints to align the feature space with kinematic principles;and(3)Two-stage Decoupled Architecture,enabling efficient and controllable feature learning through unsupervised pre-training and frozen-feature transfer.Experimental results demonstrate that LMAE significantly improves the average recognition accuracy for 20-class maneuvers compared to traditional end-to-end models,while significantly accelerating convergence speed.The contributions of this work lie in:introducing high-masking-rate autoencoders into low-informationdensity trajectory analysis,proposing a feature engineering framework with enhanced controllability and efficiency,and providing a novel technical pathway for intelligent air combat decision-making systems.
基金supported by the National Basic Research Program of China(Grant No.2012CB921603)the 863 Program(Grant No.2011AA010801)+4 种基金the National Natural Science Foundation of China(Grant Nos.61008012,10934004,60978001,60978018,and 11174187)the International Science&Technology Cooperation Program of China(Grant No.2011DFA12490)the National Natural Science Foundation of China for Excellent Research Team(Grant No.61121064)the Natural Science Foundation of Shanxi Province,China(Grant Nos.2011011004 and 2011081030)the New Teacher Fund of the Ministry of Education of China(Grant No.20101401120004)
文摘The high-resolution photoassociation spectrum of the ultracold cesium molecular 0+ state below the 6S1/2 + 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is observed from the depen dence of the trap-loss probability on the photoassociation laser intensity. The corresponding resonant line width is also demonstrated to increase linearly with increasing photoassociation laser intensity. Our experimental data have good con sistency with the theoretical saturation model of Bohn and Julienne [Bohn J L and Julienne P S 1999 Phys. Rev. A 60 1].
基金supported by the National Natural Science Foundation of China(Nos.21573059,12274118 and 22208088)Henan Center for Outstanding Overseas Scientists(No.GZS2023007)Special Project for Fundamental Research in University of Henan Province(No.22ZX013)。
文摘Sluggish sulfur conversion kinetics pose an ongoing challenge in lithium-sulfur batteries(LSBs).Here,we present a solution through far-reaching long-range electronic regulation(LRER)on single-atom active sites.N-doped carbons(Co-NC)are implanted with densely-distributed Co single atoms,and supported on Ti_(3)C_(2)T_(x)MXene substrates to assemble 3D Co-NC/MXene catalyst.MXene effectively mediates interlayer charge transfer(~0.70|e|)contrasted with popular carbon materials(~0.06|e|)to produce LRER through surrounding carbon atoms.The synergy of LRER with near-range electronic regulation(NRER)tunes electronic structures,and enhances heterostructural stability,thus provoking desirous catalytic kinetics of Co single atoms in sulfur reduction.Thereby,the Co-NC/MXene/S cathodes exhibit impressive rate performance and excellent cycling stability(only 0.015%capacity decay per cycle over 600 cycles at 4 C)in LSBs,surpassing state-of-the-art sulfur cathodes.This work reveals the importance of LRER for improved catalysis,and provides new guidance to tailor heterostructures to achieve high-efficient catalysts in various process.
基金supports by the National Natural Science Foundation of China(NSFC,Grant No.52271113)the Natural Science Foundation of Shaanxi Province,China(2020JM 218)the Fundamental Research Funds for the Central Universities(CHD300102311405)。
文摘Catalysts with asymmetric coordination exhibit excellent electrocatalytic activity due to changes in the active sites,which affect the arrangement of reactants and catalytic activity/selectivity.Hence,the exploration of the inherent characteristics of active sites within diverse coordination environments holds great significance for the experimental design of catalytic structures.Single-atom catalysts(SACs)characterized by high coordination with four carbons(26 candidates)and low coordination with dinitrogen(27candidates)are constructed using nitrogen-doped graphdiyne derivatives(NGDY)as the substrate.Additionally,5 species of dual-atom catalysts(DACs)with coexistence of both high and low coordination sites are also developed and their nitrogen reduction reaction(NRR)activities are systematically investigated by density functional theory.The results indicate that metals with low coordination exhibit superior catalytic performance,such as Mo^(L)-NGDY(U_(L)=-0.30 V)and Nb^(L)-NGDY(U_(L)=-0.32 V).Furthermore,machine learning(ML)methods have deeply analyzed and elucidated the primary intrinsic characteristics that influence catalytic performance.These results not only unveil the underlying mechanisms behind the exceptional catalytic performance exhibited by low-coordination metal atoms,but also provide relevant and significant descriptors.More importantly,based on an investigation of the catalytic activity of a series of DACs,the“buffer and low-coordination accumulate”asymmetric coordination mechanism is proposed to unveil the long-range interactions between low and high coordination atoms.Due to this remote communication,MoNb-NGDY(U_(L)=-0.09/-0.37 V)exhibits the best NRR activity.This mechanism provides valuable insights into the origin of long-range bipartite interactions and inspires the design and synthesis of NRR catalysts with different coordination environments.
基金supported by the National Natural Science Foundation of China(Grant No.11962002)the Innovation Project of the Guangxi Graduate Education(Grant Nos.YCBZ2021021 and YCSW2022070).
文摘A Hamiltonian mean-field model with long-range four-body interactions is proposed.The model describes a long-range mean-field system in which N unit-mass particles move on a unit circle.Each particleθi interacts with any three other particles through an infinite-range cosine potential with an attractive interaction(ε>0).By applying a method that remaps the average phase of global particle pairs onto a new unit circle,and using the saddle-point technique,the partition function is solved analytically after introducing four-body interactions,yielding expressions for the free energy f and the energy per particle U.These results were further validated through numerical simulations.The results show that the system undergoes a second-order phase transition at the critical energy Uc.Specifically,the critical energy corresponds to U_(c)=0.32 when the coupling constantε=5,and U_(c)=0.63 whenε=10.Finally,we calculated the system’s largest Lyapunov exponentλand kinetic energy fluctuationsΣthrough numerical simulations.It is found that the peak of the largest Lyapunov exponentλoccurs slightly below the critical energy Uc,which is consistent with the point of maximum kinetic energy fluctuationsΣ.And there is a scaling law ofΣ/N^(1/2)∝λbetween them.
基金supported by the National Natural Science Foundation of China(Nos.12205259 and 12147101)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)with No.G1323523064.
文摘In this study,we performed a systematic analysis of the multiplicity dependence of hadron production at mid-rapidity(|y|<0.5),ranging from the light to the charm sector in proton-proton(pp)collisions at√s=13 TeV.This study used a multi-phase transport(AMPT)model coupled with PYTHIA8 initial conditions.We investigated the baryon-to-meson and the strange-to-non-strange meson ratios varying with the charged particle density.By tuning the coalescence parameters,the AMPT model provides a reasonable description of the experimental data for the inclusive production of both light and charm hadrons,comparable to the string fragmentation model calculations with color reconnection effects.Additionally,we analyzed the relative production of hadrons by examining the self-normalized particle ratios as a function of the charged hadron density.Our findings suggest that parton evolution effects and the coalescence hadronization process in the AMPT model result in a strong flavor hierarchy in the multiplicity dependence of the baryon-to-meson ratio.Furthermore,our investigation of the p_(T) differential double ratio of the baryon-to-meson fraction between high-and low-multiplicity events revealed distinct modifications to the flavor associated baryon-to-meson ratio p_(T) shape in high-multiplicity events when comparing the coalescence hadronization model to the color reconnection model.These observations highlight the importance of understanding the hadronization process in high-energy pp collisions through comprehensive multiplicity-dependent multi-flavor analysis.
基金supported by the National Natural Science Foundation of China(Grant No.12375025).
文摘We investigate the parity-time(PT)symmetry-breaking quantum phase transition in a one-dimensional(1D)bosonic lattice featuring cavity-mediated long-range interactions and spatially staggered dissipation.By mapping the system to an effective spin chain under the constraints of hard-core bosons and integrating the mean-field decoupling approach with biorthogonal basis formalism,we derive a self-consistency equation.Numerical simulation results validate that the derived equation quantitatively captures thePT-symmetry order parameter’s phase diagram.Our findings reveal that coherent hopping maintainsPTsymmetry through quantum fluctuations.Conversely,cavity-engineered long-range interactions,in synergy with staggered dissipation,act in opposition to drive symmetry breaking.This competitive interplay can inspire further exploration of tunable quantum phase transitions in non-Hermitian systems.
基金supported by the Director General,Indian Council of Agricultural Research(ICAR),New Delhithe Director,ICAR-National Rice Research Institute,Cuttack.
文摘Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,Sub1 and Dro1(Δbp:10 Mb),as well as Sub1 and TPP7(Δbp:6 Mb)were identified to exhibit long-range linkage disequilibrium(LRLD).Meta-QTL analysis further revealed that Sub1 and TPP7 co-segregated for tolerance to submergence at the germination and seedling stages.Based on this,we hypothesized that LRLD might influence plant responses to consecutive stresses.To test this hypothesis,we developed a structured recombinant inbred line population from a cross between Bhalum 2 and Nagina 22,with alleles(Sub1 and TPP7)in linkage equilibrium.Mendelian randomization analysis validated that the parental alleles,rather than the recombinant alleles of Sub1 and TPP7,significantly influenced 13 out of 41 traits under consecutive stress conditions.Additionally,16 minor additive effect QTLs were detected between the genomic regions,spanning Sub1 and TPP7 for various traits.A single allele difference between these genomic regions enhanced crown root number,root dry weight,and specific root area by 11.45%,15.69%,and 33.15%,respectively,under flooded germination conditions.Candidate gene analysis identified WAK79 and MRLK59 as regulators of stress responses during flooded germination,recovery,and subsequent water deficit conditions.These findings highlight the critical role of parental allele combinations and genomic regions between Sub1 and TPP7 in regulating the stress responses under consecutive stresses.Favourable haplotypes derived from these alleles can be utilized to improve stress resilience in direct-seeded rice.
基金the Fund of Science and Technology Innovation Project of Chinese Academy of Chinese Medical Sciences Project:Self-service Acupuncture Smoking Cessation Research and Development(No.CI2021A03506)Fund of Capital Health Development Special Research Project:Research on Development and Clinical Applicalion of Wrist Acupuncture Smoking Cessation Instrument(No.2022-1-4281)。
文摘OBJECTIVE:To observe the effect of different acupuncture frequencies on the abstinence rate which could be used as a reference for optimizing acupuncture cessation programs.METHODS:From July 2018 to June 2022,a total of 220 smokers were recruited based on inclusion criteria and randomly divided into the high-frequency acupuncture group(HF group,n=110):5 times a week from the 1st to the 4th week,from weeks 5 to 8,three times a week and the low-frequency acupuncture group(LF group,n=110):3 times a week from the 1st to the 4th week,from weeks 5 to 8,twice a week,then treated for 8 weeks and followup at 1 month in Beijing.RESULTS:In total,162 subjects completed the whole study with a drop-out rate of 20.45%.The expiratory CO point abstinence rate was HF group 53/110(48.18%)vs LF group 41/110(37.27%)in Week 8(P=0.102)and HF group 46/110(41.82%)vs LF group 45/110(40.91%)in Week 12(P=0.891)and the HF acupuncture and LF acupuncture were nearly equal in the 8-week abstinence rate.In addition,both HF and LF acupuncture significantly reduced Fagerstr?m test for nicotine dependence scale(FTND)scores(P<0.05),Minnesota nicotine withdrawal scale(MNWS)scores(P<0.05),and Brief Questionnaire of Smoking Urges scale(QSU-Brief)scores(P<0.05),but HF acupuncture showed some superiority over LF acupuncture in relieving patients'smoking cravings(P<0.05).CONCLUSIONS:The study initially showed that both high-frequency acupuncture and low-frequency acupuncture treatment were safe and effective on smoking cessation for 8 weeks,but high-frequency acupuncture was advantageous in reducing smoking cravings.More accurate acupuncture frequency needs to be validated through larger clinical studies to optimize acupuncture smoking cessation programs.
基金supported by the Beijing Natural Science Foundation Key Research Program(Grant Z240026)the Beijing National Laboratory for Molecular Sciences.
文摘Electrocatalysis has been investigated as a promising strategy to utilize green electricity to produce renewable fuels,valuable chemicals,and treat pollutants.Electrode kinetic analysis is a potent technique in interrogating reaction mechanisms and evaluating the electrocatalysts.Electron transfer(ET)and proton‐coupled electron transfer(PCET)processes are widely present in reaction networks of electrocatalysis.pH dependence of the kinetics is frequently employed to evaluate whether an elementary step involves proton participation,which is determined by both the reversibility and the specific reactants of electrode reactions.In this article,we discuss the pH dependence of two widely used formulations of the Butler–Volmer kinetics for a model PCET step and highlight a potential pitfall in kinetic analysis.This work aims to provide guiding principles for distinguishing ET and PCET steps via kinetic measurements in electrolytes in a broad range pH values.
基金supported by the Jiangsu Funding Program for Excellent Postdoctoral Talent (Grant No.2023ZB397)the Project funded by China Postdoctoral Science Foundation (Grant No.2023M732986).
文摘Nanomaterials have garnered recognition for their notable surface effects and demonstration of superior mechanical properties.Previous studies on the surface effects of nanomaterials,employing the finite element method,often relied on simplified twodimensional models due to theoretical complexities.Consequently,these simplified models inadequately represent the mechanical properties of nanomaterials and fail to capture the substantial impact of surface effects,particularly the curvature dependence of nanosurfaces.This study applies the principle of minimum energy and leverages the Steigmann-Ogden surface theory of nanomaterials to formulate a novel finite element surface element that comprehensively accounts for surface effects.We conducted an analysis of the stress distribution and deformation characteristics of four typical 2D and 3D nanomaterial models.The accuracy of the developed surface element and finite element calculation method was verified through comparison with established references.The resulting finite element model provides a robust and compelling scientific approach for accurately predicting the mechanical performance of nanomaterials.
基金financially supported by the National Key Re-search and Development Program of China(No.2017YFB0701801)。
文摘Partial phase transformation in NiTi-based refrigerants usually enables efficient and durable elastocaloric cooling,but its thermomechanical behavior with varying temperatures remains unclear.Keeping this in view,the elastocaloric effect of NiTi under incomplete transformation across 15-100℃ is investigated and a superelastic deformation window between 25 and 85℃ is identified.Synchronous infrared thermography and digital image correlation,and an innovative macro-micro phase-field model are employed to examine martensitic transformation and elastocaloric properties of NiTi within the superelastic window.Experimental and simulated results consistently reveal that the spatiotemporal thermal profiles correlate with Lüders strain band evolution.As superelastic deformation temperature increases,strain localization intensifies,with Lüders bands favoring an inward strain growth over an outward expansion,resulting in a smaller yet more deformed martensitic transformation zone.The aggravated strain inhomogeneity makes the local endothermic undercooling tested at 85℃ up to about twice(−30.05℃)that at 25℃(−15.32℃),boosting the global cooling capacity by 65%,despite constant strain.The seeming contradiction between the larger elastocaloric effect and the narrower apparent martensitic transformation zone is elucidated by recourse to the simulations.It is found that the martensitic transformation within the Lüders bands is incomplete,proceeding in a macroscopically uniform but microscopically heterogeneous manner.Elevated temperatures within the superelastic window increase the transformed volume fraction and enhance martensitic transformation,thereby strengthening the global caloric effect.The work sheds light on the interplay between partial martensitic transformation and thermal behavior in NiTi under varying superelastic deformation temperatures,providing insights for advanced elastocaloric cooling applications.
基金supported by grants from the Scientific Research Fund project of Education Department of Yunnan Province(2024J0314)Joint Special Project on Basic Research of Yunnan Provincial Department of Science and Technology and Kunming Medical University(202501AY070001-206).
文摘Objective:To evaluate the global liter-ature output on the relationship between brain-derived neurotrophic factor(BDNF)and cognitive function in al-cohol dependence syndrome using bibliometric methods and explore the status and trends in this field.Method:The literature on the application of BDNF in cognitive impairment caused by alcohol dependence syndrome published from 1995 to 2023 were retrieved from Web of Science,and the relevant information(publication characteristics,country and institution,author,number of publications,citation,journal and research field,corresponding author,key words,etc.)was recorded.The bibliometrix R package was used for quantitative and qualitative analysis of publication output and author contributions.Result:A total of 99 articles were included.The overall number of publications in this field has increased over time.The countries and institutions that contributed the most to the field were the United States and the Academy of Medical Sciences of Iranian universities,respectively.Most of the authors were from the United States,followed by Spain,China,and Iran.Ceccanti M,Fiore M were the most productive authors.Publications with Ceccanti M had the highest h-index.The most cited reference author is Haenninen H(227 citations),and the number one published journal is Alcohol.Most articles were published in 2020(n=12)and 2022(n=11),followed by 2019 and 2021(n=10).The corresponding author has the largest number of publications from the United States,and more publications from a single country tend to have more cooperation from other countries.BDNF and alcohol appeared more frequently in various keyword clouds.However,significant differences remained in the author keyword cloud,keyword plus word cloud,and paper topic word cloud.Conclusion:BDNF has great potential in the application of cognitive dysfunction caused by alcohol dependence syndrome.Bibliometric methods and data visualization techniques can help understand the current state of research progress and enable relevant scholars and practitioners to predict the development trends in this field.
基金supported by the State Key Laboratory of Traction Power,Southwest Jiaotong University (TPL2104)the National Natural Science Foundation of China (61833002).
文摘In the field of data-driven bearing fault diagnosis,convolutional neural network(CNN)has been widely researched and applied due to its superior feature extraction and classification ability.However,the convolutional operation could only process a local neighborhood at a time and thus lack the ability of capturing long-range dependencies.Therefore,building an efficient learning method for long-range dependencies is crucial to comprehend and express signal features considering that the vibration signals obtained in a real industrial environment always have strong instability,periodicity,and temporal correlation.This paper introduces nonlocal mean to the CNN and presents a 1D nonlocal block(1D-NLB)to extract long-range dependencies.The 1D-NLB computes the response at a position as a weighted average value of the features at all positions.Based on it,we propose a nonlocal 1D convolutional neural network(NL-1DCNN)aiming at rolling bearing fault diagnosis.Furthermore,the 1D-NLB could be simply plugged into most existing deep learning architecture to improve their fault diagnosis ability.Under multiple noise conditions,the 1D-NLB improves the performance of the CNN on the wheelset bearing data set of high-speed train and the Case Western Reserve University bearing data set.The experiment results show that the NL-1DCNN exhibits superior results compared with six state-of-the-art fault diagnosis methods.
基金funded by the National Natural Science Foundation of China(No.32270554,32400400).
文摘The post-fledging period, extending from fledging to independence, is a crucial life stage characterized by high mortality due to fledglings' limited mobility and inexperience. During this stage, fledglings gradually increase their mobility, leave their parents, disperse from their natal site, and respond to the challenges of new environments. Characterizing these post-fledging movements and space use is essential for understanding juvenile survival strategies and devising targeted conservation measures. The Crested Ibis (Nipponia nippon), an endangered species and a highly protected animals at the national level in China, has seen limited research on its post-fledging movements and space use. From 2015 to 2023, we utilized biologgers, combined with field surveys, to study the movement and space use characteristics of 37 fledglings in Hanzhong City, Shaanxi Province, China, over a two-month post-fledging period. We quantified changes in activity levels (based on overall dynamic body acceleration), independence timing, onset of post-fledging dispersal, habitat selection, and daily activity rhythms after independence. Our results revealed individuals began independent living 26.23 ± 2.34 days post-fledging and onset of dispersal at 25.58 ± 2.33 days, with a range area at the natal of 2.08 ± 0.56 km^(2). The initial 30 days post-fledging are characterized as an ontogenetic phase marked by a rapid increase in body activity level. Fledglings preferred paddy fields during the independent period rather than the forests they relied on before independence. Interestingly, the daily activity rhythm, particularly foraging behavior, peaked at noon—contrasting with the expected morning and evening activity peaks—likely as an adaptation to avoid periods of peak human activity. Additionally, drowning, collisions, and predation in paddy fields are noteworthy causes of fledgling mortality. Consequently, we recommend protecting a 2-km^(2) area around the nest site for at least two-month post-fledging, implementing safety measures around power lines and cesspools. Additionally, reducing human disturbances near foraging habitats and expanding space within paddy fields would help mitigate survival pressures on fledglings.
基金supported by the National Natural Science Foundation of China(Grant Nos.62074036,61674038,and 11574302)the Foreign Cooperation Project of Fujian Province,China(Grant No.2023I0005)+2 种基金the Open Research Fund Program of the State Key Laboratory of Low Dimensional Quantum Physics(Grant No.KF202108)the National Key Research and Development Program of China(Grant No.2016YFB0402303)the Foundation of the Fujian Provincial Department of Industry and Information Technology of China(Grant No.82318075).
文摘The thickness dependence of linearly polarized light-induced momentum anisotropy and the inverse spin Hall effect(PISHE)in topological insulator(TI)Bi_(2)Te_(3)films has been investigated.A significant enhancement of the PISHE signal is observed in the 12-quintuple-layer(QL)Bi_(2)Te_(3)film compared with that of the 3-and 5-QL samples,whereas a minimal value of photoinduced momentum anisotropy is found in the 12-QL sample.The photoinduced momentum anisotropy and the PISHE in Bi_(2)Te_(3)films are more than three and two orders of magnitude larger than those in Bi2Se3 films grown on SrTiO_(3)substrates,respectively.The 3-QL sample exhibits a sinusoidal dependence of the PISHE current on the light spot position,while the 5-QL and 12-QL samples show aW-shaped dependence,which arises from the different angles between the coordinate axis x and the in-plane crystallographic axis of the Bi_(2)Te_(3)films.Our findings demonstrate the critical role of film thickness in modulating both the photoinduced momentum anisotropy and the PISHE current,thereby suggesting a thickness-engineering strategy for designing novel optoelectronic devices based on TIs.
基金Project(51205302)supported by the National Natural Science Foundation of ChinaProject(2013JM7017)supported by the Natural Science Basic Research Plan in Shanxi Province of ChinaProject(K5051304006)supported by the Fundamental Research Funds for the Central Universities,China
文摘Based on the EAM potential, a molecular dynamics study on the tensile properties of ultrathin nickel nanowires in the (100〉 orientation with diameters of 3.94, 4.95 and 5.99 nm was presented at different temperatures and strain rates. The temperature and strain rate dependences of tensile properties were investigated. The simulation results show that the elastic modulus and the yield strength are gradually decreasing with the increase of temperature, while with the increase of the strain rate, the stress--strain curves fluctuate more intensely and the ultrathin nickel nanowires rupture at one smaller and smaller strain. At an ideal temperature of 0.01 K, the yield strength of the nanowires drops rapidly with the increase of strain rate, and at other temperatures the strain rate has a little influence on the elastic modulus and the yield strength. Finally, the effects of size on the tensile properties of ultrathin nickel nanowires were briefly discussed.