In this work,we study the impacts of the isospin-independent momentum-dependent interaction(MDI)and near-threshold NN→NΔcross sections(σ_(NN→NΔ))on the nucleonic flow and pion production observables in the ultra-...In this work,we study the impacts of the isospin-independent momentum-dependent interaction(MDI)and near-threshold NN→NΔcross sections(σ_(NN→NΔ))on the nucleonic flow and pion production observables in the ultra-relativistic quantum molecular dynamics(UrQMD)model.With the updated isospin-independent MDI and the near-threshold NN→NΔcross sections in the Ur QMD model,17 observables,which are the directed flow(v_(1))and elliptic flow(v_(2))of neutrons,protons,Hydrogen(H),and charged particles as a function of transverse momentum(p_t∕A)or normalized rapidity(y^(lab)_0),and the observables constructed from them,the charged pion multiplicity(M(π))and its ratio(M(π^(-))∕M(π^(+))),can be simultaneously described at certain forms of symmetry energy.The refinement of the UrQMD model provides a solid foundation for further understanding the effects of the missed physics,such as the threshold effect,the pion potential,and the momentum-dependent symmetry potential.Circumstantial constraints on the symmetry energy at the flow characteristic density 1.2±0.6ρ_(0)and the pion characteristic density 1.5±0.5ρ_(0)were obtained with the current version of UrQMD,and the corresponding symmetry energies were S(1.2ρ_(0))=34±4 MeV and S(1.5ρ_(0))=36±8 MeV,respectively.Furthermore,the discrepancies between the data and the calculated results of v_(2)^(n)and v_(2)^(9)at high p_(t)(rapidity)imply that the roles of the missing ingredients,such as the threshold effect,the pion potential,and the momentum-dependent symmetry potential,should be investigated by differential observables,such as the momentum and rapidity distributions of the nucleonic and pionic probes over a wide beam energy range.展开更多
The Antarctic Tianmu Staring Observation Project(ATSOP)entails the deployment of 30 small-aperture,wide-field optical telescopes in the Antarctic region.The system will perform long-term continuous observation campaig...The Antarctic Tianmu Staring Observation Project(ATSOP)entails the deployment of 30 small-aperture,wide-field optical telescopes in the Antarctic region.The system will perform long-term continuous observation campaigns over a period of 100 d(24 h per day)per year,as well as short-time-scale sampling at intervals of 5 min,across a sky area of approximately 1200 square degrees centered near the south celestial pole.We have assessed the types of small solar system bodies detectable by the ATSOP telescopes,as well as the associated scientific research opportunities.Our analysis indicates that the ATSOP is capable of detecting near-Earth objects(NEOs)with all orbital inclinations,as well as high-inclination small bodies located beyond the main asteroid belt.Potential research topics include the discovery and identification of small bodies,orbit determination,physical characterization,investigation into the activity characteristics and evolutionary patterns of active small bodies,and studies on their dynamical evolution.Observations of NEOs can also contribute to planetary defense efforts.On the basis of pilot observational data collected by the Antarctic Tianmu prototype(AT-Proto)between February 20 and October 26,2023,a total of 478 asteroids and 9 comets were successfully identified,demonstrating the effectiveness of the ATSOP system in observing small solar system bodies.Looking ahead,with anticipated performance enhancements in the second-generation AT-Proto,the limiting magnitude will increase from 16 to 18,thereby enabling the detection of an even greater number of small solar system bodies.展开更多
This paper investigates the consensus tracking control problem for high order nonlinear multi-agent systems subject to non-affine faults,partial measurable states,uncertain control coefficients,and unknown external di...This paper investigates the consensus tracking control problem for high order nonlinear multi-agent systems subject to non-affine faults,partial measurable states,uncertain control coefficients,and unknown external disturbances.Under the directed topology conditions,an observer-based finite-time control strategy based on adaptive backstepping and is proposed,in which a neural network-based state observer is employed to approximate the unmeasurable system state variables.To address the complexity explosion problem associated with the backstepping method,a finite-time command filter is incorporated,with error compensation signals designed to mitigate the filter-induced errors.Additionally,the Butterworth low-pass filter is introduced to avoid the algebraic ring problem in the design of the controller.The finite-time stability of the closed-loop system is rigorously analyzed with the finite-time Lyapunov stability criterion,validating that all closed-loop signals of the system remain bounded within a finite time.Finally,the effectiveness of the proposed control strategy is verified through a simulation example.展开更多
Objective:To evaluate the clinical efficacy of blood-letting cupping combined with manual lymphatic drainage in treating breast cancer-related lymphedema(BCRL)and explore its mechanism of action from both traditional ...Objective:To evaluate the clinical efficacy of blood-letting cupping combined with manual lymphatic drainage in treating breast cancer-related lymphedema(BCRL)and explore its mechanism of action from both traditional Chinese medicine and modern medical perspectives,providing a scientific basis and novel therapeutic approaches for clinical management of BCRL.Methods:Patients with BCRL admitted to the outpatient and inpatient departments of Hebei University Affiliated Hospital were enrolled.A prospective randomized controlled trial design was adopted,with eligible patients randomly assigned to a treatment group and a control group.The control group received manual lymphatic drainage alone,while the treatment group received manual lymphtic drainage combined with blood-letting cupping therapy.Posttreatment comparisons evaluated upper limb circumference reduction,edema severity grading,and upper limb functional scores.Vital signs and adverse reactions during treatment were recorded for both groups.Statistical software analyzed the data.Results:The treatment group demonstrated significantly greater reduction in upper limb circumference,improvement in edema severity,and higher upper limb function scores compared to the control group(P<0.05).Vital signs remained stable throughout treatment in both groups.No severe adverse reactions occurred in the treatment group;only isolated cases of mild skin itching were reported,which resolved after symptomatic management.Conclusion:The combination of bloodletting cupping and manual lymphatic drainage demonstrates reliable efficacy in treating BCRL,effectively alleviating edema symptoms and improving upper limb function with high safety.Its mechanism may relate to traditional Chinese medicine principles of“unblocking meridians,promoting blood circulation,and resolving stasis”and modern medical concepts of“enhancing local blood circulation,facilitating lymphatic drainage,and reducing inflammatory responses”.展开更多
Here we report on simultaneous lidar observations of sporadic Ni(Nis)layers and sporadic Na(Nas)layers in the atmosphere over Yanqing,Beijing(40.42°N,116.02°E)from April 2019 to October 2022.During 343 night...Here we report on simultaneous lidar observations of sporadic Ni(Nis)layers and sporadic Na(Nas)layers in the atmosphere over Yanqing,Beijing(40.42°N,116.02°E)from April 2019 to October 2022.During 343 nights of observation,68 Nis and 56 Nas were observed.The seasonal variation of Nis and Nas was also obtained,with the highest occurrence of Nis being in July(43%)and that of Nas being in June(61%).We found that the seasonal variation of Nis is similar to that of Nas and that both occur more frequently in summer than in winter.In addition,we found 23 events in which Nis and Nas occur simultaneously.The average peak altitude of Nas is approximately 1 km higher than that of Nis,and the peak density ratio of Nas to Nis is approximately 5,which is half the density ratio of the two main layers.Additionally,the strength factor for Nas is smaller than that for Nis.Through data analysis of sporadic E layers(Es),we found that Nis and Nas has a significant correlation with Es.The neutralization rates of Ni^(+)/Na^(+)were calculated according to the dissociative recombination reaction of Ni^(+)/Na^(+)and the WACCM-Ni(Whole Atmosphere Community Climate Model of Ni).The production rates of Ni and Na were estimated to be approximately 1:4.4,which is consistent with the density ratio of Nis to Nas.The results showed that the neutralization reaction of Ni+,Na+,and electrons in Es is the main reason for the formation of the Nis layer and the Nas layer.展开更多
Unmanned combat aerial vehicles require lightweight,stealth-capable exhaust systems.However,traditional metallic nozzles increase radar detectability and reduce range,while advanced composites offer high performance b...Unmanned combat aerial vehicles require lightweight,stealth-capable exhaust systems.However,traditional metallic nozzles increase radar detectability and reduce range,while advanced composites offer high performance but are expensive.Therefore,to improve the operational range and survivability of unmanned combat aerial vehicles,a lightweight,high-temperature-resistant,oxidation-resistant,and low-observable composite exhaust nozzle is developed to replace conventional metallic straight-type nozzles.The nozzle features a double serpentine shape to reduce radar and infrared signatures and is manufactured as a monolithic structure using the filament winding process,accommodating the complex geometry and large size(length:1.8 m,width:0.8 m).The exhaust nozzle consists of a ceramic matrix composite made of silicon carbide fibers and a silicon oxycarbide matrix,which absorbs and scatters radio frequency signals while withstanding prolonged exposure to high-temperature(700℃)oxidizing environments typical of engine exhaust gases.The polysiloxane resin used to produce the silicon oxycarbide matrix poses significant challenges owing to its low tackiness and high viscosity variations depending on the presence of nanoparticles,making filament winding difficult.These challenges are addressed by optimizing resin viscosity and winding pattern design.As a result,the tensile strength of the composite specimens fabricated with the optimized viscosity increases by 228.03% before pyrolysis and 97.68%after pyrolysis,compared with that of the non-optimized specimens.In addition,the density and tensile strength of the composite processed via three cycles of polymer infiltration and pyrolysis increased by 13.08% and 80.37%,respectively,compared to those of the non-densified composite.High-temperature oxidation and flame tests demonstrate exceptional thermal and oxidative stability.Furthermore,when compared with carbon fiber-reinforced ceramic matrix composites,the developed composite exhibits a permittivity at least two levels lower and a reflection loss below7 dB within the frequency range of 9.3-10.9 GHz,underscoring its superior electromagnetic stealth performance.展开更多
Energy transfers among internal waves in the northern South China Sea are not well characterized,particularly during typhoons,owing to the lack of in situ observations.Based on high-resolution mooring data collected d...Energy transfers among internal waves in the northern South China Sea are not well characterized,particularly during typhoons,owing to the lack of in situ observations.Based on high-resolution mooring data collected during Typhoon Trami(2024),this study reveals the occurrence of robust vertical energy redistribution among diurnal internal tides(D1 ITs)and near-inertial waves(NIWs).Strikingly,the typhoon not only amplified the NIW energy but also triggered an unexpected surge in the D1 IT energy.The observed average net energy transfer rate of 1×10^(-7) W kg^(−1) from typhoon-forced NIWs to D1 ITs occurred at water depths of 120-170 m.Further bispectral analysis indicated that the energy transfer is driven by nonlinear wave—wave interaction.These results reveal the existence of a new energy transfer pathway—from atmospheric forcing to D1 ITs—and redefine the redistribution of the internal wave energy during extreme weather events.展开更多
This paper investigates the adaptive optimal tracking control(AOTC)for underactuated surface vessels(USVs).Compared to the majority of existing studies,the control strategy in this paper innovatively combines an exten...This paper investigates the adaptive optimal tracking control(AOTC)for underactuated surface vessels(USVs).Compared to the majority of existing studies,the control strategy in this paper innovatively combines an extended state observer(ESO)with reinforcement learning(RL).The designed ESO has high estimation accuracy and robust disturbance rejection capabilities for the unmeasurable information for USVs.To obtain the AOTC,the actor–critic(AC)networks based on RL are constructed to solve the Hamilton–Jacobi–Bellman(HJB)equations.Due to the uncertainties,it is challenging to obtain the optimal controller by directly solving the HJB equations.To address this issue,this paper employs neural networks(NNs)to approximate the uncertainties and solves the optimal controller via AC-RL and ESO.In addition,the adaptive parameters of the optimal controller is trained in parallel with AC networks,which can ensure that the trained networks can further improve tracking performance.The boundedness of AOTC for USVs is shown by Lyapunov stability theorem.Finally,simulation results demonstrate the effectiveness of the proposed algorithm.展开更多
State Field Observation and Research Station of Debris Flow in Dongchuan,Yunnan is also named Dongchuan Debris Flow Observation and Research Station,Chinese Academy of Sciences.The study area,Jiangjia Ravine,is about ...State Field Observation and Research Station of Debris Flow in Dongchuan,Yunnan is also named Dongchuan Debris Flow Observation and Research Station,Chinese Academy of Sciences.The study area,Jiangjia Ravine,is about 48.6 km2 and characterized by intense tectonism.Accumulated clastic detritus is the main source of the materials in the debris flows when an intense rainfall occurs.The recorded highest density and sediment transport are 2370 kg/m^(3) and 6.079×10^(6) kg/s,respectively.The ravine is now called the“debris flow museum”in China and supplies advantageous research conditions.展开更多
Lithium metal batteries(LMBs)represent a promising solution for next-generation energy storage due to their high energy density,but the growth of lithium dendrites presents significant challenges to their performance ...Lithium metal batteries(LMBs)represent a promising solution for next-generation energy storage due to their high energy density,but the growth of lithium dendrites presents significant challenges to their performance and safety.This review provides a comprehensive overview of the mechanisms behind lithium dendrite formation and the role of in situ/operando observation and phase field simulation in understanding and mitigating this issue,The key driving factors of dendrite growth,such as lithium-ion flux heterogeneity,surface defects,and localized stress,are explored through advanced experimental techniques,which enable real-time visualization of dendrite nucleation and growth dynamics.Complementarily,phase field simulations provide insights into subsurface and temporal evolution of dendrites by modeling thermodynamic and kinetic processes,while machine learning techniques optimize simulation accuracy through data-driven parameter refinement.The integration of experimental observations with simulation models holds great potential in improving understanding and predictive capabilities.Despite ongoing progress,challenges remain in resolving technical limitations in observation techniques,improving computational efficiency,and fostering interdisciplinary collaboration.This review highlights the synergy between experimental and computational strategies in advancing the development of LMBs and calls for continued research to overcome existing hurdles and unlock the full potential of lithium metal anodes.展开更多
The spatial variability in the atmospheric CO_(2)and CH_(4)concentrations in urban land is affected by the source type,source distribution,and emission intensity in the cityscape.In this study,we analyzed vehicle-moun...The spatial variability in the atmospheric CO_(2)and CH_(4)concentrations in urban land is affected by the source type,source distribution,and emission intensity in the cityscape.In this study,we analyzed vehicle-mounted measurements of street-level CO_(2)and CH_(4)concentrations in Hangzhou—a large metropolitan area in the Yangtze River Delta in eastern China.The results revealed that CO_(2)and CH_(4)emission hotspots did not overlap geographically,with the former occurring as linear features at elevated road intersections and expressways and the latter occurring at waste treatment facilities(sewage treatment plants and landfills).The CH_(4):CO_(2)emission ratios(ppb ppm^(-1))were ranked in increasing order as follows:traffic(1.01±1.82;mean±1 SD);overall(3.46±2.71);sewage treatment(12.76±2.50);and landfill(36.50±10.15).Waste treatment was largely responsible for the increased overall emission ratio,supporting this source category as a major contributor to the CH_(4)budget in this city and suggesting a negligible role of domestic appliances(cookstoves and water heaters).A two-source mixing model calculation indicated that 99.9%of nonelectric vehicles in Hangzhou were gasoline-powered,revealing a recent shift in vehicle fuel composition from gasoline/natural gas to gasoline/electricity.The methodology established in this study is applicable to cities elsewhere.展开更多
The spin-dependent conductance and magnetoresistance ratio （MRR） for a semiconductor heterostructures consisting of two magnetic barriers with different height and space have been investigated by the transfer-matrix...The spin-dependent conductance and magnetoresistance ratio （MRR） for a semiconductor heterostructures consisting of two magnetic barriers with different height and space have been investigated by the transfer-matrix method. It is shown that the splitting of the conductance for parallel and antiparallel magnetization configurations results in tremendous spin-dependent MRR, and the maximal MRRs reach 5300% and 3800% for the magnetic barrier spaces W = 81.3 and 243.9 nm, respectively. The obtained spin-filtering transport property of nanostructures with magnetic barriers may be useful to magnetic-barrier-based spintronics.展开更多
We obtain uncertainty and certainty relations of state-independent form for the three Paufi observables with use of the Renyi entropies of order α∈ （0; 1]. It is shown that these entropic bounds are tight in the s...We obtain uncertainty and certainty relations of state-independent form for the three Paufi observables with use of the Renyi entropies of order α∈ （0; 1]. It is shown that these entropic bounds are tight in the sense that they are always reached with certain pure states. A new result is the condition for equality in Renyi-entropy uncertainty relations for the Pauli observables. Upper entropic bounds in the pure-state case are also novel. Combining the presented bounds leads to a band, in which the rescaled average Renyi a-entropy ranges for a pure measured state. A width of this band is compared with the Tsallis formulation derived previously.展开更多
We study the spin-dependent thermopower in a double-quantum-dot(DQD) embedded between the left and right two-dimensional electron gases(2DEGs) in doped quantum wells under an in-plane magnetic field. When the separati...We study the spin-dependent thermopower in a double-quantum-dot(DQD) embedded between the left and right two-dimensional electron gases(2DEGs) in doped quantum wells under an in-plane magnetic field. When the separation between the DQD is smaller than the Fermi wavelength in the 2DEGs, the asymmetry in the dots' energy levels leads to pronounced quantum interference effects characterized by the Dicke line-shape of the conductance, which are sensitive to the properties of the 2DEGs. The magnitude of the thermopower, which denotes the generated voltage in response to an infinitesimal temperature difference between the two 2DEGs under vanishing charge current, will be obviously enhanced by the Dicke effect. The application of the in-plane magnetic field results in the polarization of the spin-up and spin-down conductances and thermopowers, and enables an efficient spin-filter device in addition to a tunable pure spin thermopower in the absence of its charge counterpart.展开更多
Oxygen deficient Nd_(0.67)Sr_(0.33)MnO_(3-δ) ceramic samples were prepared using conventional ceramic technology.A colossal electroresistance(CER)effect was found in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.The electrical...Oxygen deficient Nd_(0.67)Sr_(0.33)MnO_(3-δ) ceramic samples were prepared using conventional ceramic technology.A colossal electroresistance(CER)effect was found in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.The electrical transport is magnetically coupled and spin-dependent over grain or phase boundaries.Electrical-field-induced changes of the spin array orientations inside of and between the magnetic domains by grain or phase boundaries have to be concluded for the strong electroresistive effect in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.展开更多
A on,dimensional ring subject to Rashba spin-orbit coupling is investigated. When it is attached to a lead with spin-dependent chemical potential, there will be charge current in the ring. The charge current response ...A on,dimensional ring subject to Rashba spin-orbit coupling is investigated. When it is attached to a lead with spin-dependent chemical potential, there will be charge current in the ring. The charge current response is resonantly maximized when the Fermi energy of the lead is equal to any energy level of the 1D ring. And if two probes are attached to the ring, the electric voltage between them creates sawtooth-like wave, which indicates the direction of the charge current. A ferromagnetic lead can also induce persistent charge current, which can be detected by magnetization intensity measurement.展开更多
Spin-polarized transport through a precessing magnetic spin coupled to ferromagnetic electrodes is studied using a non-equilibrium Green＇s function approach. The characteristic of conductance is obtained at zero temp...Spin-polarized transport through a precessing magnetic spin coupled to ferromagnetic electrodes is studied using a non-equilibrium Green＇s function approach. The characteristic of conductance is obtained at zero temperature. We find that competition between spin-exchange interaction on the spin site and spin-orbit interaction in the barriers dominates the resonant behavior of conductance. In a parallel configuration, conductance peaks have identical amplitude. With the angle θ increasing, the width of resonant peaks is broadened or narrowed for different spin coherent states. In an anti-parallel case, spin-flip tunneling in the barriers will essentially enhance amplitude of the conductance peak.展开更多
We present a phase-and spin-dependent manipulation of leakage of a Majorana mode into a double quantum dot.We study the density of states(DOS)to show the effect of phase change factor on the Majorana leakage into(out)...We present a phase-and spin-dependent manipulation of leakage of a Majorana mode into a double quantum dot.We study the density of states(DOS)to show the effect of phase change factor on the Majorana leakage into(out)of a double quantum dot.The DOS is derived from the Green's function of the quantum dot by the equation of motion method,and exhibits a formant structure whenφ=0,2πand a resonance shape whenφ=0.5πand 1.5π.Also,it changes more strongly under the spin-polarized coefficient than the non-polarized lead.Such a theoretical model can be modified to explore the spin-dependent effect in the hybrid Majorana quantum dot system.展开更多
It is commonly known that the hydrodynamic equations can be derived from the Boltzmann equation. In this paper, we derive similar spin-dependent balance equations based on the spinor Boltzmann equation. Besides the us...It is commonly known that the hydrodynamic equations can be derived from the Boltzmann equation. In this paper, we derive similar spin-dependent balance equations based on the spinor Boltzmann equation. Besides the usual charge current, heat current, and pressure tensor, we also explore the characteristic spin accumulation and spin current as well as the spin-dependent pressure tensor and heat current in spintronics. The numerical results of these physical quantities are demonstrated using an example of spin-polarized transport through a mesoscopic ferromagnet.展开更多
Influence of the choice of the NN potential model governing the deuteron wave function on the observables for coherent π0-photoproduction on the deuteron near η-threshoM is investigated by using a three-body model ...Influence of the choice of the NN potential model governing the deuteron wave function on the observables for coherent π0-photoproduction on the deuteron near η-threshoM is investigated by using a three-body model for the intermediate ηN N system with separable two-body interactions. Results for unpolarized differential cross section and polarization observables are predicted. It is revealed that the choice of the NN potential model has a visible effect on the differential cross section and most of the polarization observables, especially in the photon energy range of 600-800 MeV and extreme backward pion angles. We find that the deviation among results obtained by using different deuteron wave functions is quite large. The use of the CD-Bonn NN potential for deuteron wave function doubles the differential cross section in this kinematic region. Compared with the experimental data from CLAS collaboration for differential cross section, sizeable discrepancies are found.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11875323,12275359,12205377,12335008,U2032145,11790320,11790323,11790325,and 11961141003)the National Key R&D Program of China(No.2018 YFA0404404)+2 种基金the Continuous Basic Scientific Research Project(No.WDJC-2019-13)the China Institute of Atomic Energy(No.YZ222407001301)the Leading Innovation Project of the CNNC(Nos.LC192209000701 and LC202309000201)。
文摘In this work,we study the impacts of the isospin-independent momentum-dependent interaction(MDI)and near-threshold NN→NΔcross sections(σ_(NN→NΔ))on the nucleonic flow and pion production observables in the ultra-relativistic quantum molecular dynamics(UrQMD)model.With the updated isospin-independent MDI and the near-threshold NN→NΔcross sections in the Ur QMD model,17 observables,which are the directed flow(v_(1))and elliptic flow(v_(2))of neutrons,protons,Hydrogen(H),and charged particles as a function of transverse momentum(p_t∕A)or normalized rapidity(y^(lab)_0),and the observables constructed from them,the charged pion multiplicity(M(π))and its ratio(M(π^(-))∕M(π^(+))),can be simultaneously described at certain forms of symmetry energy.The refinement of the UrQMD model provides a solid foundation for further understanding the effects of the missed physics,such as the threshold effect,the pion potential,and the momentum-dependent symmetry potential.Circumstantial constraints on the symmetry energy at the flow characteristic density 1.2±0.6ρ_(0)and the pion characteristic density 1.5±0.5ρ_(0)were obtained with the current version of UrQMD,and the corresponding symmetry energies were S(1.2ρ_(0))=34±4 MeV and S(1.5ρ_(0))=36±8 MeV,respectively.Furthermore,the discrepancies between the data and the calculated results of v_(2)^(n)and v_(2)^(9)at high p_(t)(rapidity)imply that the roles of the missing ingredients,such as the threshold effect,the pion potential,and the momentum-dependent symmetry potential,should be investigated by differential observables,such as the momentum and rapidity distributions of the nucleonic and pionic probes over a wide beam energy range.
基金supported by the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted by the Ministry of Finance of China(MOF)and administered by the Chinese Academy of Sciences(CAS),the National Natural Science Foundation of China(Nos.12173093 and 11973094)a science research grant from the China Manned Space Project(No.CMS-CSST-2021-B08).
文摘The Antarctic Tianmu Staring Observation Project(ATSOP)entails the deployment of 30 small-aperture,wide-field optical telescopes in the Antarctic region.The system will perform long-term continuous observation campaigns over a period of 100 d(24 h per day)per year,as well as short-time-scale sampling at intervals of 5 min,across a sky area of approximately 1200 square degrees centered near the south celestial pole.We have assessed the types of small solar system bodies detectable by the ATSOP telescopes,as well as the associated scientific research opportunities.Our analysis indicates that the ATSOP is capable of detecting near-Earth objects(NEOs)with all orbital inclinations,as well as high-inclination small bodies located beyond the main asteroid belt.Potential research topics include the discovery and identification of small bodies,orbit determination,physical characterization,investigation into the activity characteristics and evolutionary patterns of active small bodies,and studies on their dynamical evolution.Observations of NEOs can also contribute to planetary defense efforts.On the basis of pilot observational data collected by the Antarctic Tianmu prototype(AT-Proto)between February 20 and October 26,2023,a total of 478 asteroids and 9 comets were successfully identified,demonstrating the effectiveness of the ATSOP system in observing small solar system bodies.Looking ahead,with anticipated performance enhancements in the second-generation AT-Proto,the limiting magnitude will increase from 16 to 18,thereby enabling the detection of an even greater number of small solar system bodies.
基金supported in part by the Beijing Natural Science Foundation under Grant 4252050in part by the National Science Fund for Distinguished Young Scholars under Grant 62425304in part by the Basic Science Center Programs of NSFC under Grant 62088101.
文摘This paper investigates the consensus tracking control problem for high order nonlinear multi-agent systems subject to non-affine faults,partial measurable states,uncertain control coefficients,and unknown external disturbances.Under the directed topology conditions,an observer-based finite-time control strategy based on adaptive backstepping and is proposed,in which a neural network-based state observer is employed to approximate the unmeasurable system state variables.To address the complexity explosion problem associated with the backstepping method,a finite-time command filter is incorporated,with error compensation signals designed to mitigate the filter-induced errors.Additionally,the Butterworth low-pass filter is introduced to avoid the algebraic ring problem in the design of the controller.The finite-time stability of the closed-loop system is rigorously analyzed with the finite-time Lyapunov stability criterion,validating that all closed-loop signals of the system remain bounded within a finite time.Finally,the effectiveness of the proposed control strategy is verified through a simulation example.
文摘Objective:To evaluate the clinical efficacy of blood-letting cupping combined with manual lymphatic drainage in treating breast cancer-related lymphedema(BCRL)and explore its mechanism of action from both traditional Chinese medicine and modern medical perspectives,providing a scientific basis and novel therapeutic approaches for clinical management of BCRL.Methods:Patients with BCRL admitted to the outpatient and inpatient departments of Hebei University Affiliated Hospital were enrolled.A prospective randomized controlled trial design was adopted,with eligible patients randomly assigned to a treatment group and a control group.The control group received manual lymphatic drainage alone,while the treatment group received manual lymphtic drainage combined with blood-letting cupping therapy.Posttreatment comparisons evaluated upper limb circumference reduction,edema severity grading,and upper limb functional scores.Vital signs and adverse reactions during treatment were recorded for both groups.Statistical software analyzed the data.Results:The treatment group demonstrated significantly greater reduction in upper limb circumference,improvement in edema severity,and higher upper limb function scores compared to the control group(P<0.05).Vital signs remained stable throughout treatment in both groups.No severe adverse reactions occurred in the treatment group;only isolated cases of mild skin itching were reported,which resolved after symptomatic management.Conclusion:The combination of bloodletting cupping and manual lymphatic drainage demonstrates reliable efficacy in treating BCRL,effectively alleviating edema symptoms and improving upper limb function with high safety.Its mechanism may relate to traditional Chinese medicine principles of“unblocking meridians,promoting blood circulation,and resolving stasis”and modern medical concepts of“enhancing local blood circulation,facilitating lymphatic drainage,and reducing inflammatory responses”.
基金supported by the Specialized Research Fund for State Key Laboratories,Chinese Meridian Project,the Specialized Research Fund for the State Key Laboratory of Solar Activity and Space Weather,postgraduate Education Reform and Quality Improvement Project of Henan Province(Grant No.YJS2024JD32)Natural Science Foundation Project of Henan Province(Grant No.242300420253)National Natural Science Foundation of China for Young Scientists(Grant No.42504156)funding.
文摘Here we report on simultaneous lidar observations of sporadic Ni(Nis)layers and sporadic Na(Nas)layers in the atmosphere over Yanqing,Beijing(40.42°N,116.02°E)from April 2019 to October 2022.During 343 nights of observation,68 Nis and 56 Nas were observed.The seasonal variation of Nis and Nas was also obtained,with the highest occurrence of Nis being in July(43%)and that of Nas being in June(61%).We found that the seasonal variation of Nis is similar to that of Nas and that both occur more frequently in summer than in winter.In addition,we found 23 events in which Nis and Nas occur simultaneously.The average peak altitude of Nas is approximately 1 km higher than that of Nis,and the peak density ratio of Nas to Nis is approximately 5,which is half the density ratio of the two main layers.Additionally,the strength factor for Nas is smaller than that for Nis.Through data analysis of sporadic E layers(Es),we found that Nis and Nas has a significant correlation with Es.The neutralization rates of Ni^(+)/Na^(+)were calculated according to the dissociative recombination reaction of Ni^(+)/Na^(+)and the WACCM-Ni(Whole Atmosphere Community Climate Model of Ni).The production rates of Ni and Na were estimated to be approximately 1:4.4,which is consistent with the density ratio of Nis to Nas.The results showed that the neutralization reaction of Ni+,Na+,and electrons in Es is the main reason for the formation of the Nis layer and the Nas layer.
基金supported by the Agency for Defense Development Grant Funded by the Korean Government(Grant No.912822501).
文摘Unmanned combat aerial vehicles require lightweight,stealth-capable exhaust systems.However,traditional metallic nozzles increase radar detectability and reduce range,while advanced composites offer high performance but are expensive.Therefore,to improve the operational range and survivability of unmanned combat aerial vehicles,a lightweight,high-temperature-resistant,oxidation-resistant,and low-observable composite exhaust nozzle is developed to replace conventional metallic straight-type nozzles.The nozzle features a double serpentine shape to reduce radar and infrared signatures and is manufactured as a monolithic structure using the filament winding process,accommodating the complex geometry and large size(length:1.8 m,width:0.8 m).The exhaust nozzle consists of a ceramic matrix composite made of silicon carbide fibers and a silicon oxycarbide matrix,which absorbs and scatters radio frequency signals while withstanding prolonged exposure to high-temperature(700℃)oxidizing environments typical of engine exhaust gases.The polysiloxane resin used to produce the silicon oxycarbide matrix poses significant challenges owing to its low tackiness and high viscosity variations depending on the presence of nanoparticles,making filament winding difficult.These challenges are addressed by optimizing resin viscosity and winding pattern design.As a result,the tensile strength of the composite specimens fabricated with the optimized viscosity increases by 228.03% before pyrolysis and 97.68%after pyrolysis,compared with that of the non-optimized specimens.In addition,the density and tensile strength of the composite processed via three cycles of polymer infiltration and pyrolysis increased by 13.08% and 80.37%,respectively,compared to those of the non-densified composite.High-temperature oxidation and flame tests demonstrate exceptional thermal and oxidative stability.Furthermore,when compared with carbon fiber-reinforced ceramic matrix composites,the developed composite exhibits a permittivity at least two levels lower and a reflection loss below7 dB within the frequency range of 9.3-10.9 GHz,underscoring its superior electromagnetic stealth performance.
基金supported by the National Key R&D Plan Program of China [Grant number 2021YFC3101500]the National Natural Science Foundation of China [Grant number 42305014,42506024]。
文摘Energy transfers among internal waves in the northern South China Sea are not well characterized,particularly during typhoons,owing to the lack of in situ observations.Based on high-resolution mooring data collected during Typhoon Trami(2024),this study reveals the occurrence of robust vertical energy redistribution among diurnal internal tides(D1 ITs)and near-inertial waves(NIWs).Strikingly,the typhoon not only amplified the NIW energy but also triggered an unexpected surge in the D1 IT energy.The observed average net energy transfer rate of 1×10^(-7) W kg^(−1) from typhoon-forced NIWs to D1 ITs occurred at water depths of 120-170 m.Further bispectral analysis indicated that the energy transfer is driven by nonlinear wave—wave interaction.These results reveal the existence of a new energy transfer pathway—from atmospheric forcing to D1 ITs—and redefine the redistribution of the internal wave energy during extreme weather events.
基金supported by the National Natural Science Foundation of China under Grants 62203338,62173259 and U1913602Zhejiang Provincial Natural Science Foundation of China under Grant LZ24F0390006the Postdoctoral Science Foundation of China under Grant 2022M722485.
文摘This paper investigates the adaptive optimal tracking control(AOTC)for underactuated surface vessels(USVs).Compared to the majority of existing studies,the control strategy in this paper innovatively combines an extended state observer(ESO)with reinforcement learning(RL).The designed ESO has high estimation accuracy and robust disturbance rejection capabilities for the unmeasurable information for USVs.To obtain the AOTC,the actor–critic(AC)networks based on RL are constructed to solve the Hamilton–Jacobi–Bellman(HJB)equations.Due to the uncertainties,it is challenging to obtain the optimal controller by directly solving the HJB equations.To address this issue,this paper employs neural networks(NNs)to approximate the uncertainties and solves the optimal controller via AC-RL and ESO.In addition,the adaptive parameters of the optimal controller is trained in parallel with AC networks,which can ensure that the trained networks can further improve tracking performance.The boundedness of AOTC for USVs is shown by Lyapunov stability theorem.Finally,simulation results demonstrate the effectiveness of the proposed algorithm.
文摘State Field Observation and Research Station of Debris Flow in Dongchuan,Yunnan is also named Dongchuan Debris Flow Observation and Research Station,Chinese Academy of Sciences.The study area,Jiangjia Ravine,is about 48.6 km2 and characterized by intense tectonism.Accumulated clastic detritus is the main source of the materials in the debris flows when an intense rainfall occurs.The recorded highest density and sediment transport are 2370 kg/m^(3) and 6.079×10^(6) kg/s,respectively.The ravine is now called the“debris flow museum”in China and supplies advantageous research conditions.
基金the financial support of the National Natural Science Foundation of China(Nos.12172206 and 11972218)。
文摘Lithium metal batteries(LMBs)represent a promising solution for next-generation energy storage due to their high energy density,but the growth of lithium dendrites presents significant challenges to their performance and safety.This review provides a comprehensive overview of the mechanisms behind lithium dendrite formation and the role of in situ/operando observation and phase field simulation in understanding and mitigating this issue,The key driving factors of dendrite growth,such as lithium-ion flux heterogeneity,surface defects,and localized stress,are explored through advanced experimental techniques,which enable real-time visualization of dendrite nucleation and growth dynamics.Complementarily,phase field simulations provide insights into subsurface and temporal evolution of dendrites by modeling thermodynamic and kinetic processes,while machine learning techniques optimize simulation accuracy through data-driven parameter refinement.The integration of experimental observations with simulation models holds great potential in improving understanding and predictive capabilities.Despite ongoing progress,challenges remain in resolving technical limitations in observation techniques,improving computational efficiency,and fostering interdisciplinary collaboration.This review highlights the synergy between experimental and computational strategies in advancing the development of LMBs and calls for continued research to overcome existing hurdles and unlock the full potential of lithium metal anodes.
基金supported by the National Natural Science Foundation of China(Grant Nos.U24A20590,42021004)the Joint funds of the Zhejiang Provincial Natural Science Foundation of China(GrantNo.LZJMZ23D050002)+2 种基金the 333 Project of Jiangsu Province(Grant No.BRA2022023)the Natural Science Foundation of Jiangsu Province for Distinguished Young Scholars(Grant No.BK20220055)the Key Laboratory of Ecosystem Carbon Source and Sink,China Meteorological Administration(Grant No.ECSS-CMA202302)。
文摘The spatial variability in the atmospheric CO_(2)and CH_(4)concentrations in urban land is affected by the source type,source distribution,and emission intensity in the cityscape.In this study,we analyzed vehicle-mounted measurements of street-level CO_(2)and CH_(4)concentrations in Hangzhou—a large metropolitan area in the Yangtze River Delta in eastern China.The results revealed that CO_(2)and CH_(4)emission hotspots did not overlap geographically,with the former occurring as linear features at elevated road intersections and expressways and the latter occurring at waste treatment facilities(sewage treatment plants and landfills).The CH_(4):CO_(2)emission ratios(ppb ppm^(-1))were ranked in increasing order as follows:traffic(1.01±1.82;mean±1 SD);overall(3.46±2.71);sewage treatment(12.76±2.50);and landfill(36.50±10.15).Waste treatment was largely responsible for the increased overall emission ratio,supporting this source category as a major contributor to the CH_(4)budget in this city and suggesting a negligible role of domestic appliances(cookstoves and water heaters).A two-source mixing model calculation indicated that 99.9%of nonelectric vehicles in Hangzhou were gasoline-powered,revealing a recent shift in vehicle fuel composition from gasoline/natural gas to gasoline/electricity.The methodology established in this study is applicable to cities elsewhere.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10574042 and 10974052)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20060542002)
文摘The spin-dependent conductance and magnetoresistance ratio （MRR） for a semiconductor heterostructures consisting of two magnetic barriers with different height and space have been investigated by the transfer-matrix method. It is shown that the splitting of the conductance for parallel and antiparallel magnetization configurations results in tremendous spin-dependent MRR, and the maximal MRRs reach 5300% and 3800% for the magnetic barrier spaces W = 81.3 and 243.9 nm, respectively. The obtained spin-filtering transport property of nanostructures with magnetic barriers may be useful to magnetic-barrier-based spintronics.
文摘We obtain uncertainty and certainty relations of state-independent form for the three Paufi observables with use of the Renyi entropies of order α∈ （0; 1]. It is shown that these entropic bounds are tight in the sense that they are always reached with certain pure states. A new result is the condition for equality in Renyi-entropy uncertainty relations for the Pauli observables. Upper entropic bounds in the pure-state case are also novel. Combining the presented bounds leads to a band, in which the rescaled average Renyi a-entropy ranges for a pure measured state. A width of this band is compared with the Tsallis formulation derived previously.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61274101,51362031,and 11675023)the Innovation Development Fund of China Academy of Engineering Physics(CAEP)(Grant No.ZYCX1921-02)+2 种基金the Presidential Foundation of CAEP(Grant No.YZ2015014)the Initial Project of University of Electronic Science and Technology of China,Zhongshan Institute(Grant No.415YKQ02)Science and Technology Bureau of Zhongshan,China(Grant Nos.417S26 and 180809162197886)
文摘We study the spin-dependent thermopower in a double-quantum-dot(DQD) embedded between the left and right two-dimensional electron gases(2DEGs) in doped quantum wells under an in-plane magnetic field. When the separation between the DQD is smaller than the Fermi wavelength in the 2DEGs, the asymmetry in the dots' energy levels leads to pronounced quantum interference effects characterized by the Dicke line-shape of the conductance, which are sensitive to the properties of the 2DEGs. The magnitude of the thermopower, which denotes the generated voltage in response to an infinitesimal temperature difference between the two 2DEGs under vanishing charge current, will be obviously enhanced by the Dicke effect. The application of the in-plane magnetic field results in the polarization of the spin-up and spin-down conductances and thermopowers, and enables an efficient spin-filter device in addition to a tunable pure spin thermopower in the absence of its charge counterpart.
基金Project supported by the National Natural Science Foundation of China(10774040)Excellent Young Scientist Foundation of Hubei Province(2006ABB032)
文摘Oxygen deficient Nd_(0.67)Sr_(0.33)MnO_(3-δ) ceramic samples were prepared using conventional ceramic technology.A colossal electroresistance(CER)effect was found in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.The electrical transport is magnetically coupled and spin-dependent over grain or phase boundaries.Electrical-field-induced changes of the spin array orientations inside of and between the magnetic domains by grain or phase boundaries have to be concluded for the strong electroresistive effect in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.
文摘A on,dimensional ring subject to Rashba spin-orbit coupling is investigated. When it is attached to a lead with spin-dependent chemical potential, there will be charge current in the ring. The charge current response is resonantly maximized when the Fermi energy of the lead is equal to any energy level of the 1D ring. And if two probes are attached to the ring, the electric voltage between them creates sawtooth-like wave, which indicates the direction of the charge current. A ferromagnetic lead can also induce persistent charge current, which can be detected by magnetization intensity measurement.
文摘Spin-polarized transport through a precessing magnetic spin coupled to ferromagnetic electrodes is studied using a non-equilibrium Green＇s function approach. The characteristic of conductance is obtained at zero temperature. We find that competition between spin-exchange interaction on the spin site and spin-orbit interaction in the barriers dominates the resonant behavior of conductance. In a parallel configuration, conductance peaks have identical amplitude. With the angle θ increasing, the width of resonant peaks is broadened or narrowed for different spin coherent states. In an anti-parallel case, spin-flip tunneling in the barriers will essentially enhance amplitude of the conductance peak.
基金the Science Foundation of Civil Aviation Flight University of China(Grant No.JG2019-19)。
文摘We present a phase-and spin-dependent manipulation of leakage of a Majorana mode into a double quantum dot.We study the density of states(DOS)to show the effect of phase change factor on the Majorana leakage into(out)of a double quantum dot.The DOS is derived from the Green's function of the quantum dot by the equation of motion method,and exhibits a formant structure whenφ=0,2πand a resonance shape whenφ=0.5πand 1.5π.Also,it changes more strongly under the spin-polarized coefficient than the non-polarized lead.Such a theoretical model can be modified to explore the spin-dependent effect in the hybrid Majorana quantum dot system.
基金Project supported by the National Natural Science Foundation of China(Grant No.11274378)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB08-3)the MOST of China(Grant No.2013CB933401)
文摘It is commonly known that the hydrodynamic equations can be derived from the Boltzmann equation. In this paper, we derive similar spin-dependent balance equations based on the spinor Boltzmann equation. Besides the usual charge current, heat current, and pressure tensor, we also explore the characteristic spin accumulation and spin current as well as the spin-dependent pressure tensor and heat current in spintronics. The numerical results of these physical quantities are demonstrated using an example of spin-polarized transport through a mesoscopic ferromagnet.
文摘Influence of the choice of the NN potential model governing the deuteron wave function on the observables for coherent π0-photoproduction on the deuteron near η-threshoM is investigated by using a three-body model for the intermediate ηN N system with separable two-body interactions. Results for unpolarized differential cross section and polarization observables are predicted. It is revealed that the choice of the NN potential model has a visible effect on the differential cross section and most of the polarization observables, especially in the photon energy range of 600-800 MeV and extreme backward pion angles. We find that the deviation among results obtained by using different deuteron wave functions is quite large. The use of the CD-Bonn NN potential for deuteron wave function doubles the differential cross section in this kinematic region. Compared with the experimental data from CLAS collaboration for differential cross section, sizeable discrepancies are found.
