This paper proposes a trajectory tracking control scheme for vertical/short take-off and landing(V/STOL)vehicles.Owing to their high number of controllable degrees of freedom and strong nonlinearity,the design of flig...This paper proposes a trajectory tracking control scheme for vertical/short take-off and landing(V/STOL)vehicles.Owing to their high number of controllable degrees of freedom and strong nonlinearity,the design of flight control systems for such vehicles presents considerable challenges,particularly in developing controllers capable of accurately tracking specified trajectories.Building on existing control strategies for various vehicle types,this study introduces an extended control framework tailored for V/STOL systems.The proposed scheme consists of two nested loops:an outer position control loop and an inner attitude control loop.The position loop employs a proportional-integral-derivative(PID)control algorithm,whereas the attitude loop utilizes an anti-saturation integral sliding mode control algorithm.This approach effectively alleviates the integral oversaturation issue inherent in conventional sliding mode methods and suppresses buffeting through a boundary layer technique.Simulation results demonstrate the efficacy of the proposed control strategy.展开更多
This study investigates the width of the secondary eyewall(SE)immediately following its formation in tropical cyclones with surface environmental winds aligned and counter-aligned with environmental vertical wind shea...This study investigates the width of the secondary eyewall(SE)immediately following its formation in tropical cyclones with surface environmental winds aligned and counter-aligned with environmental vertical wind shear(VWS),using idealized numerical experiments.Results reveal that the SE develops greater radial extent when surface winds align with VWS compared to counter-aligned conditions.In alignment configurations,shear-enhanced surface winds on the right flank amplify surface enthalpy fluxes,thereby elevating boundary-layer entropy within the downshear outer-core region.Subsequently,more vigorous outer rainbands develop,inducing marked acceleration of tangential winds in the outer core preceding SE formation.The resultant radial expansion of supergradient winds near the boundary-layer top triggers widespread convective activity immediately beyond the inner core.Progressive axisymmetrization of this convective forcing ultimately generates an expansive SE structure.展开更多
This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlyin...This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.展开更多
The eddies in the southernmost southern Indian Ocean exert major dynamical and biogeochemical influences on the Earth system.Therefore,disentangling the relative contributions of vertical pumping and horizontal transp...The eddies in the southernmost southern Indian Ocean exert major dynamical and biogeochemical influences on the Earth system.Therefore,disentangling the relative contributions of vertical pumping and horizontal transport to water-property anomalies in the eddy cores is of fundamental importance.Here,the authors introduce a temperaturesalinity gradient-ratio approach(the"R-method")that compares vertical and meridional gradients to quantitatively separate the two processes.Application of the R-method to three-dimensional Argo observations reveals that horizontal transport,rather than vertical pumping,predominantly governs the observed temperature and salinity anomalies within eddy cores in the SIO.Independent theoretical estimations based on background meridional gradients,together with composites formed on isopycnal surfaces,further corroborate this conclusion.The results challenge the conventional assumption that vertical pumping invariably controls eddy-core property anomalies and demonstrate the utility of the R-method for diagnosing eddy impacts in climate and biogeochemical studies.展开更多
The dense heterogeneous network provides standardized connectivity and access guarantees for 5G communication services.However,the complex network environment and high level of dynamism pose challenges to network sele...The dense heterogeneous network provides standardized connectivity and access guarantees for 5G communication services.However,the complex network environment and high level of dynamism pose challenges to network selection decisions.Existing vertical handover algorithms often overlook the dynamic nature of user mobility and network condition,resulting in problems such as handover failure and frequent handover,ultimately impacting the quality of the user communication service.To address these problems,we propose an intelligent switching method,iMALSTM-DQN,which integrates an improved Multi-level Associative Long Short-Term Memory model(iMALSTM)with Deep Reinforcement Learning(DRL).The algorithm leverages iMALSTM to predict the global network state in the next moment based on the global user movement trajectory and historical network status information within a region,thereby enhancing the prediction accuracy of network states.Subsequently,based on the predicted network state,we employ the Deep Q Network(DON)model to make handover decisions,adaptively determining the optimal switching and network selection strategy through interaction with the environment.Experimental results demonstrate that the proposed algorithm enhances decision timeliness,significantly reduces the number of switch failures,and alleviates the problem of frequent handovers resulting from network dynamics.展开更多
Two-step-processed(TSP)inverted p-i-n perovskite solar cells(PSCs)have demonstrated significant promise in tandem applications.However,the power conversion efficiency(PCE)of TSP p-i-n PSCs rarely exceeds 24%.Here,we d...Two-step-processed(TSP)inverted p-i-n perovskite solar cells(PSCs)have demonstrated significant promise in tandem applications.However,the power conversion efficiency(PCE)of TSP p-i-n PSCs rarely exceeds 24%.Here,we demonstrate that TSP perovskite films exhibit a vertically gradient distribution of residual PbI_(2)clusters,which form Schottky heterojunctions with the perovskite,leading to substantial interfacial energy-level mismatches within NiO_(x)-based TSP p-i-n PSCs.These limitations were effectively addressed via a vertical interfacial engineering enabled by dual-interface modification incorporating tin trifluoromethanesulfonate(Sn(OTF)_(2))and 4-Fluorophenylethylamine chloride(F-PEA)at the NiO_(x)/perovskite and perovskite/C60 interfaces,respectively.The functional Sn(OTF)_(2)not only enhances the conductivity of NiO_(x)films but also suppresses ion migration,while inducing the formation of a Pb-Sn mixed perovskite interlayer that precisely regulates the energy level at the NiO_(x)/perovskite interface.Complementally,F-PEA post-treatment effectively converts surface residual PbI_(2)clusters into a 2D perovskite capping layer,which simultaneously passivates surface defects and enhances energy-level alignment at the perovskite/C60 interface.Consequently,the optimized NiO_(x)-based TSP p-i-n PSCs achieve a notable PCE of 25.6%with superior operational stability.This study elucidates the underlying mechanisms limiting the efficiency of TSP p-i-n PSCs,while establishing design principles for these devices targeting 26%efficiency.展开更多
The vertical heterogeneity of the pore structure in deep coal seams with varying ash yields is a key control for coalbed methane storage and producibility;however,its specific impact on gas adsorption is not clearly d...The vertical heterogeneity of the pore structure in deep coal seams with varying ash yields is a key control for coalbed methane storage and producibility;however,its specific impact on gas adsorption is not clearly defined.The focus of this study is the No.8 coal seam of the Carboniferous Benxi Formation in the Central-Eastern Ordos Basin.By integrating microscopic identification,proximate analysis,gas adsorption(CO_(2),N_(2),and CH_(4)),and the multifractal theory,we quantitatively characterized the nanopore structure(micropores<2 nm and mesopores 2 nm-100 nm)of coal reservoirs with varying ash yields.The results indicate that(1)ash yield is the primary factor that controls the vertical evolution of pore structures in coal seams.In low-ash yield coal seams,the extent of thermal evolution and ash yield jointly constrain the heterogeneity of pore size distribution.In mediumto high-ash yield coal seams,the heterogeneity of pore structure and pore size distribution are predominantly constrained by ash yield.(2)As the ash yield vertically increases,the mesoporous pore volume and specific surface area initially decrease and subsequently increase,while the contribution of micropores to both pore volume and specific surface area continuously diminishes.Consequently,the total pore volume and specific surface area of the coal samples exhibit a two-stage reduction close to an ash yield threshold of approximately 20%.(3)Further,the Langmuir volume for CH_(4)adsorption sharply declines below the 20%threshold,followed by a gradual decrease;in contrast,the Langmuir pressure initially decreases and subsequently increases.Hence,the vertical increase in ash yield constrains the development of pore systems and diminishes pore connectivity,thereby reducing methane adsorption capacity and adversely affecting coalbed methane productivity.(4)Low-ash yield coal reservoirs are characterized by a rapid gas breakthrough and high productivity,whereas medium-ash yield coal reservoirs generally require prolonged depressurization to achieve peak gas production.These findings reveal that in medium-high rank coal,ash yield―and not thermal evolution―is the main factor that controls vertical pore evolution and methane adsorption efficiency.The quantitative ash yield threshold(20%)established in this study provides a practical criterion for evaluating reservoir quality and predicting vertical variations in gas storage potential in the Ordos Basin.展开更多
As a key precursor of hydroxyl(OH) radicals, the budget of nitrous acid(HONO) at different altitudes has received extensive attention. In this study, vertically resolved observations of HONO, NO_(2), O_(3), and HCHO w...As a key precursor of hydroxyl(OH) radicals, the budget of nitrous acid(HONO) at different altitudes has received extensive attention. In this study, vertically resolved observations of HONO, NO_(2), O_(3), and HCHO were conducted during an autumn field campaign in Beijing in 2019. The significant correlation between HONO and NO2, along with variations in their ratios across different altitudes, underscores the importance of aerosol surface chemistry in HONO formation and its altitude-dependent behavior. To enhance the model performance, the heterogeneous conversion of NO_(2) and its photochemical enhancement are incorporated into the 1D model. The simulations reveal that the nocturnal HONO production is dominated by the heterogeneous conversion of NO_(2) both at the surface and aloft. During the daytime, groundsurface sources of HONO are mainly driven by nitrate photolysis and light-enhanced heterogeneous conversion of NO_(2).Meanwhile, a large portion of the HONO generated at the surface is transported upwards through vertical mixing. In the higher atmosphere, HONO originates from vertical transport and in situ processes. As precursors of OH radicals, the observed concentrations of HONO, O_(3), and HCHO exhibit distinct diurnal variations and vertical distribution patterns.HONO contributes to OH radical production predominantly during the early morning across all layers and it even becomes the main contributor throughout the daytime in the lowest layer near the ground, while O_(3) and HCHO become more prominent towards midday, especially in the higher layers. These results will be beneficial for a deeper understanding of the atmospheric oxidation process within the urban boundary layer.展开更多
Quantifying spatial heterogeneity in soil water retention properties(SWRP)is crucial for enhancing the accuracy of hydrogeological simulations.However,studies on the spatial heterogeneity of SWRP in the Chinese Loess ...Quantifying spatial heterogeneity in soil water retention properties(SWRP)is crucial for enhancing the accuracy of hydrogeological simulations.However,studies on the spatial heterogeneity of SWRP in the Chinese Loess Plateau(CLP)remain scarce,especially at the vertical scale.We conducted laboratory tests on undisturbed loess cores collected from boreholes in CLP to analyze soil physical parameters(SPPs)and SWRP.Measured soil water characteristic curves(SWCCs)were fitted to the Brooks-Corey(BC),Fredlund-Xing(FX),and van Genuchten(vG)models.It was revealed that the FX and vG models outperformed the BC model.The geostatistical analysis identified the Gaussian model as optimal for describing the semivariograms of both SPPs and SWCC fitting parameters(FPs).Strikingly,over 90%of these parameters exhibited strong vertical spatial dependence,with an average autocorrelation length of 213.878 cm for SPPs and 320.678 cm for FPs.Moreover,SWRP was found to be significantly influenced by both SPPs and the vertical position relative to the loess ridge slope surface.Parameters near the ridge slope surface showed significantly degraded spatial dependence.These findings provide valuable insights for parameterizing the spatial heterogeneity of soil water retention properties,which are beneficial for hydrogeological modelling in shallow CLP loess strata.展开更多
Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical cra...Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical crack under combined mechanical and electric loading,considering both central and edge cracks.Using Fourier transforms and dislocation density functions,the Mode-Ⅲproblem is converted to Cauchy-type singular integral equations.The crack surface fields,intensity factors,and energy release rate are derived.The accuracy of the proposed model is verified through the finite element(FE)simulation via COMSOL Multiphysics.The results for low electron concentrations align with those of the intrinsic piezoelectric materials,validating the correctness of the present model as well.The combined effects of crack position,applied electric loading,and initial carrier concentration on the crack propagation are analyzed.The normalized electric displacement factor shows heightened sensitivity to crack size,electromechanical loading,and carrier concentration.The crack position significantly influences the crack surface fields and normalized intensity factors due to the boundary proximity effect.展开更多
To characterize the spatial patterns of vertical crustal movement of Chinese mainland,GNSS imaging technology was applied to map the tectonic deformation of the region.In this study,the vertical crustal velocities inf...To characterize the spatial patterns of vertical crustal movement of Chinese mainland,GNSS imaging technology was applied to map the tectonic deformation of the region.In this study,the vertical crustal velocities inferred from GNSS data for Chinese mainland over two decades were rigorously estimated.First,by analyzing the vertical displacement time series from continuous GNSS stations and environmental load data,we found that the annual and semi-annual vertical displacements are highly correlated.This indicates that the vertical seasonal variations on the ground surface are mainly caused by environmental loading.After removing the seasonal variations caused by environmental loads from the GNSS time series,we applied an improved PCA technique to filter out common mode errors.Next,we estimated the optimal noise models for the filtered time series and derived the vertical velocity field of Chinese mainland.Finally,we employed an empirical Spatial Structure Function(SSF)to image the tectonic deformation of Chinese mainland.This method effectively mitigates issues with abrupt circular arc-shaped boundaries in GNSS imaging caused by sparse station networks.The imaging results show that vertical crustal deformation in Chinese mainland generally ranges from-3 to 3 mm/yr,with significant spatial variability.The central and northern parts of Qinghai-Xizang Plateau are identified as primary subsidence zones,indicating that plate boundaries and tectonic compression continue to shape the crustal movement in these regions.The major uplift zones are located in northern and central China,likely linked to regional tectonic activity and plate compression.Subsidence deformation in parts of eastern China appears to be influenced by human activities.展开更多
As the frontier of multidimensional transportation systems,urban air mobility(UAM)is receiving increasing attention from international organizations,governments,and stakeholders in industry and academia owing to its h...As the frontier of multidimensional transportation systems,urban air mobility(UAM)is receiving increasing attention from international organizations,governments,and stakeholders in industry and academia owing to its high efficiency,low carbon footprint,and operational flexibility.Vertical take-off and landing(VTOL)infrastructure is the core facility that enables UAM and is therefore essential for its safe,efficient,and large-scale commercial implementation.However,the key technologies for establishing low-altitude VTOL infrastructure are still nascent,and government,industry,and academia have yet to harmonize the corresponding construction,management,and operation standards.To address this gap,we herein systematically review the related progress and trends,comprehensively surveying the key technologies of establishing VTOL infrastructure serving unmanned aerial vehicles(UAVs)and electric VTOL aircraft from three complementary perspectives of ground-side,airspace-side,and communication,navigation,surveillance,and information services.In the light of future UAM operations characterized by diverse vehicle types and dense air traffic,we propose a conceptual design for a public multioperator VTOL site to provide constructive insights into the sustainable growth of the low-altitude economy.展开更多
In the realm of Intelligent Railway Transportation Systems,effective multi-party collaboration is crucial due to concerns over privacy and data silos.Vertical Federated Learning(VFL)has emerged as a promising approach...In the realm of Intelligent Railway Transportation Systems,effective multi-party collaboration is crucial due to concerns over privacy and data silos.Vertical Federated Learning(VFL)has emerged as a promising approach to facilitate such collaboration,allowing diverse entities to collectively enhance machine learning models without the need to share sensitive training data.However,existing works have highlighted VFL’s susceptibility to privacy inference attacks,where an honest but curious server could potentially reconstruct a client’s raw data from embeddings uploaded by the client.This vulnerability poses a significant threat to VFL-based intelligent railway transportation systems.In this paper,we introduce SensFL,a novel privacy-enhancing method to against privacy inference attacks in VFL.Specifically,SensFL integrates regularization of the sensitivity of embeddings to the original data into the model training process,effectively limiting the information contained in shared embeddings.By reducing the sensitivity of embeddings to the original data,SensFL can effectively resist reverse privacy attacks and prevent the reconstruction of the original data from the embeddings.Extensive experiments were conducted on four distinct datasets and three different models to demonstrate the efficacy of SensFL.Experiment results show that SensFL can effectively mitigate privacy inference attacks while maintaining the accuracy of the primary learning task.These results underscore SensFL’s potential to advance privacy protection technologies within VFL-based intelligent railway systems,addressing critical security concerns in collaborative learning environments.展开更多
To improve the current grinding procedure of the back-up roll of CVC hot rolling mills so that the back-up roll service life can be extended, the crack initiation and propagation behavior of medium carbon bainitic bac...To improve the current grinding procedure of the back-up roll of CVC hot rolling mills so that the back-up roll service life can be extended, the crack initiation and propagation behavior of medium carbon bainitic back-up roll steel was investigated, a kind of asperity-scale, surface originated vertical short cracks occurred at 5 × 10^2 -1 × 10^4 cycles. Theoretical analysis indicated that the maximum tensile stress occurring at the back edge of the contact of asperities keeps at above 1 347. 97 MPa, and ratcheting and cyclic plastic deformation take place at such sites within 1 × 10^4 cycles. The early initiation of the vertical short cracks is caused by the asperity contact. According to the crack initiation mechanism, short crack behavior and preventive grinding strategy, steel consumption can be reduced considerably by decreasing the surface roughness and removing the asperity influenced surface thin layer at about 70%-80% of the surface distress life.展开更多
One deficiency of the NCAR Community Land Model （CLM3） is the disappearance of the simulated snow even in the middle of winter over a boreal grassland site due to unrealistically modeled high downward turbulent flux...One deficiency of the NCAR Community Land Model （CLM3） is the disappearance of the simulated snow even in the middle of winter over a boreal grassland site due to unrealistically modeled high downward turbulent fluxes. This is caused by the inappropriate treatment of the vertical snow burial fraction for short vegetation. A new snow burial fraction formulation for short vegetation is then proposed and validated using in situ observations. This modification in the CLM3 largely removes the unrealistic surface turbulent fluxes, leading to a more reasonable snowmelt process, and improves the snow water equivalent （SWE） simulation. Moreover, global offline simulations show that the proposed formulation decreases sensible and latent heat fluxes as well as the ground temperature during the snowmelt season over short vegetation dominant regions. Correspondingly, the SWE is enhanced, leading to the increase in snowmelt-induced runoff during the same period. Furthermore, sensitivity tests indicate that these improvements are insensitive to the exact functional form or parameter values in the proposed formulation.展开更多
The influence of local site effects on seismic ground motions is an important issue in seismic hazard assessment and earthquake resistant design. Determining site effects in densely populated cities built on basins ca...The influence of local site effects on seismic ground motions is an important issue in seismic hazard assessment and earthquake resistant design. Determining site effects in densely populated cities built on basins can help to reduce the earthquake hazard. Site effects of Luoyang basin are estimated by the horizontal-to-vertical spectral ratio(HVSR) method using ambient noise records from a short-period dense array. The sites in Luoyang basin are sorted into three types according to the pattern of the HVSR curves. There are cases with a single clear peak, two clear peaks, and an unclear low frequency peak or multiple peaks, which correspond to there being one large impedance contrast interface, two large interfaces, and a moderate one beneath the sites, respectively. The site effects characterized by fundamental frequency from HVSR curves are affected by underlying sedimentary layers and depth of sedimentary basement. According to our results, the existence of thick sediment layer obviously lowers the fundamental frequency to the period range from 2 to 4 s in the downtown area of Luoyang city. The ground motion will amplify when through the sites and the buildings with height of 20–50 floors can resonate at the similar frequency domain. Site effects estimation using HVSR method from a short-period dense array is an effective technique in areas of moderate seismic risk where strong motion recordings are lacking, such as the Luoyang basin.展开更多
Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation...Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.展开更多
Zika virus(ZIKV)is a mosquito-borne virus belonging to the genus Orthoflavivirus,and the family Flaviviridae.It commonly presents with febrile-like symptoms,neurological issues,and pregnancy complications in humans.Cu...Zika virus(ZIKV)is a mosquito-borne virus belonging to the genus Orthoflavivirus,and the family Flaviviridae.It commonly presents with febrile-like symptoms,neurological issues,and pregnancy complications in humans.Currently,there is no commercial vaccine or specific treatment available to prevent ZIKV infection.Therefore,controlling the epidemic's spread relies on preventing mosquitoes from transmitting the virus.Although various studies have explored the transmission of ZIKV between mosquitoes and vertebrate hosts,comprehensive research on potential mosquito-to-mosquito transmission of ZIKV remains limited.In this study,we conducted systematic laboratory investigations to assess the ability of ZIKV to spread among mosquitoes,and to evaluate the impact of ZIKV infection on mosquito development.Our findings revealed that ZIKV can be transmitted between Aedes aegypti mosquitoes both vertically and horizontally,through oviposition and contact between mosquitoes of the same or opposite sex.Additionally,we observed that ZIKV infection resulted in a reduction in the number of mosquito eggs but an increase in their size.The widespread distribution of ZIKV in infected mosquitoes and the altered levels of hormone related genes following viral infection were noted,which may contribute to viral transmission among mosquitoes and affect mosquito development.This research provides systematic experimental evidence of ZIKV transmission among mosquitoes,which is crucial for developing novel strategies to disrupt the spread of orthoflaviviruses and other mosquitoborne pathogens.展开更多
Vertical detection of volatile organic compounds(VOCs)is essential to expend our understanding of the distribution characteristics of VOCs and improve the predictive ability of existing air qualitymodels.In this work,...Vertical detection of volatile organic compounds(VOCs)is essential to expend our understanding of the distribution characteristics of VOCs and improve the predictive ability of existing air qualitymodels.In this work,we report the development of a sorbent tube sampler based on an unmanned aerial vehicle(UAV)platform.Vertical profile measurement of VOCs with a vertical resolution of 25mwas achieved.The sampler consists of five lightweight VOC sorbent tubes and a 5-way solenoid valve,making it available for collecting five atmospheric VOC samples in a single flight with a time response of less than 30min.The samplerweighed∼1.45 kg and had dimensions of 240mm×220mm×100mmwith small penetration loss(<10%)under 4-liter sampling conditions(flow rate of 200 mL/min).Commercialized SUMMA canisters were used as experimental controls to investigate the possible loss of self-made sampler for target compounds in the same sampling process.Comparison experiment on the ground showed that the concentration differences for all VOC species were lower than 0.14μg/m3,proving the good reliability for VOCs measurements using sorbent tube sampler.The UAV platform also incorporated online instruments for meteorological parameters and O_(3) measurement.The sampler was successfully applied to characterize the vertical profiles of VOCs up to 100 m in October 2023 in the Huaihe River Basin of China.The UAV platform and the sorbent tube sampler demonstrate good performance and will be a valuable and reliable tool for vertical VOCs measurement.展开更多
The increasing population and continuous urbanization make food security a key consideration in sustainable development.Efficient farming strategies with low environmental footprints are thus increasingly required to ...The increasing population and continuous urbanization make food security a key consideration in sustainable development.Efficient farming strategies with low environmental footprints are thus increasingly required to meet food demands.This study presents a design for environmentally friendly,economical,and modular vertical farming systems,in which vegetables are cultivated in a carbon dioxide(CO_(2))-enriched atmosphere enabled by direct air capture(DAC)and subjected to artificial light exposure.We established a vertical farming setup and conducted experiments to identify productive cultivation strategies by regulating lighting,CO_(2)concentration,biochar application,and plant species.Additionally,a self-developed DAC rotary adsorber was utilized to achieve stable and efficient CO_(2)enrichment.Compared with the control group,the fresh weight of the vegetables in the experimental groups increased by up to 57.5%.Furthermore,we performed a comprehensive evaluation of the design and demonstrated that integrating photovoltaic-thermal(PVT)and DAC units increased the system’s net present value(NPV)by 157%compared with a conventional design without these units.Importantly,we found it possible to maintain the low carbon footprint of the system(0.468 kg-CO_(2)equivalent·kg−1(CO_(2)eq·kg−1)-vegetable)in the production process.Parametric studies and an application analysis on a global scale reveal the wide adaptability of this strategy to diverse conditions.These findings,together with the modular characteristics of vertical farming systems,highlight the promising potential of this design to increase food security and foster sustainable agriculture.展开更多
基金supported in part by National Key Laboratory Foundation(No.STSL2024-A-04(C))。
文摘This paper proposes a trajectory tracking control scheme for vertical/short take-off and landing(V/STOL)vehicles.Owing to their high number of controllable degrees of freedom and strong nonlinearity,the design of flight control systems for such vehicles presents considerable challenges,particularly in developing controllers capable of accurately tracking specified trajectories.Building on existing control strategies for various vehicle types,this study introduces an extended control framework tailored for V/STOL systems.The proposed scheme consists of two nested loops:an outer position control loop and an inner attitude control loop.The position loop employs a proportional-integral-derivative(PID)control algorithm,whereas the attitude loop utilizes an anti-saturation integral sliding mode control algorithm.This approach effectively alleviates the integral oversaturation issue inherent in conventional sliding mode methods and suppresses buffeting through a boundary layer technique.Simulation results demonstrate the efficacy of the proposed control strategy.
基金jointly supported by the National Natural Science Foundation of China[grant numbers U2342202,42175005,and 42175016]the Qing Lan Project[grant number R2023Q06]。
文摘This study investigates the width of the secondary eyewall(SE)immediately following its formation in tropical cyclones with surface environmental winds aligned and counter-aligned with environmental vertical wind shear(VWS),using idealized numerical experiments.Results reveal that the SE develops greater radial extent when surface winds align with VWS compared to counter-aligned conditions.In alignment configurations,shear-enhanced surface winds on the right flank amplify surface enthalpy fluxes,thereby elevating boundary-layer entropy within the downshear outer-core region.Subsequently,more vigorous outer rainbands develop,inducing marked acceleration of tangential winds in the outer core preceding SE formation.The resultant radial expansion of supergradient winds near the boundary-layer top triggers widespread convective activity immediately beyond the inner core.Progressive axisymmetrization of this convective forcing ultimately generates an expansive SE structure.
基金supported by the National Natural Science Foundation of China(Grant No.42261134532,42405059,and U2342212)。
文摘This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.
基金supported by the National Natural Science Foundation of China [grant number 42176001]the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences [grant number LTO2106]the STU Scientific Research Foundation for Talents [grant number NTF21009]。
文摘The eddies in the southernmost southern Indian Ocean exert major dynamical and biogeochemical influences on the Earth system.Therefore,disentangling the relative contributions of vertical pumping and horizontal transport to water-property anomalies in the eddy cores is of fundamental importance.Here,the authors introduce a temperaturesalinity gradient-ratio approach(the"R-method")that compares vertical and meridional gradients to quantitatively separate the two processes.Application of the R-method to three-dimensional Argo observations reveals that horizontal transport,rather than vertical pumping,predominantly governs the observed temperature and salinity anomalies within eddy cores in the SIO.Independent theoretical estimations based on background meridional gradients,together with composites formed on isopycnal surfaces,further corroborate this conclusion.The results challenge the conventional assumption that vertical pumping invariably controls eddy-core property anomalies and demonstrate the utility of the R-method for diagnosing eddy impacts in climate and biogeochemical studies.
基金National Key Research and Development Program of China(No.2022YFB3903404,2024YFC3015403)National Natural Science Foundation of China(NSFC No.42271431,42271425)Hubei Province Major Science and Technology Innovation Program(2024BAA011)。
文摘The dense heterogeneous network provides standardized connectivity and access guarantees for 5G communication services.However,the complex network environment and high level of dynamism pose challenges to network selection decisions.Existing vertical handover algorithms often overlook the dynamic nature of user mobility and network condition,resulting in problems such as handover failure and frequent handover,ultimately impacting the quality of the user communication service.To address these problems,we propose an intelligent switching method,iMALSTM-DQN,which integrates an improved Multi-level Associative Long Short-Term Memory model(iMALSTM)with Deep Reinforcement Learning(DRL).The algorithm leverages iMALSTM to predict the global network state in the next moment based on the global user movement trajectory and historical network status information within a region,thereby enhancing the prediction accuracy of network states.Subsequently,based on the predicted network state,we employ the Deep Q Network(DON)model to make handover decisions,adaptively determining the optimal switching and network selection strategy through interaction with the environment.Experimental results demonstrate that the proposed algorithm enhances decision timeliness,significantly reduces the number of switch failures,and alleviates the problem of frequent handovers resulting from network dynamics.
基金financially supported by the National Nature Science Foundation of China (62504130)National Key Research and Development Program of China (2018YFB0704100)+3 种基金the Key university laboratory of highly efficient utilization of solar energy and sustainable development of Guangdong (Y01256331)the Technology Development Project of Henan Province (252102240047)the Pico Center at SUSTech CRF which receives support from the Presidential FundDevelopment and Reform Commission of Shenzhen Municipality
文摘Two-step-processed(TSP)inverted p-i-n perovskite solar cells(PSCs)have demonstrated significant promise in tandem applications.However,the power conversion efficiency(PCE)of TSP p-i-n PSCs rarely exceeds 24%.Here,we demonstrate that TSP perovskite films exhibit a vertically gradient distribution of residual PbI_(2)clusters,which form Schottky heterojunctions with the perovskite,leading to substantial interfacial energy-level mismatches within NiO_(x)-based TSP p-i-n PSCs.These limitations were effectively addressed via a vertical interfacial engineering enabled by dual-interface modification incorporating tin trifluoromethanesulfonate(Sn(OTF)_(2))and 4-Fluorophenylethylamine chloride(F-PEA)at the NiO_(x)/perovskite and perovskite/C60 interfaces,respectively.The functional Sn(OTF)_(2)not only enhances the conductivity of NiO_(x)films but also suppresses ion migration,while inducing the formation of a Pb-Sn mixed perovskite interlayer that precisely regulates the energy level at the NiO_(x)/perovskite interface.Complementally,F-PEA post-treatment effectively converts surface residual PbI_(2)clusters into a 2D perovskite capping layer,which simultaneously passivates surface defects and enhances energy-level alignment at the perovskite/C60 interface.Consequently,the optimized NiO_(x)-based TSP p-i-n PSCs achieve a notable PCE of 25.6%with superior operational stability.This study elucidates the underlying mechanisms limiting the efficiency of TSP p-i-n PSCs,while establishing design principles for these devices targeting 26%efficiency.
基金sponsored by the National Natural Science Foundation of China(Grant No.42202205)Natural Science Foundation of Shandong Province,China(Grant No.ZR2021QD072).-。
文摘The vertical heterogeneity of the pore structure in deep coal seams with varying ash yields is a key control for coalbed methane storage and producibility;however,its specific impact on gas adsorption is not clearly defined.The focus of this study is the No.8 coal seam of the Carboniferous Benxi Formation in the Central-Eastern Ordos Basin.By integrating microscopic identification,proximate analysis,gas adsorption(CO_(2),N_(2),and CH_(4)),and the multifractal theory,we quantitatively characterized the nanopore structure(micropores<2 nm and mesopores 2 nm-100 nm)of coal reservoirs with varying ash yields.The results indicate that(1)ash yield is the primary factor that controls the vertical evolution of pore structures in coal seams.In low-ash yield coal seams,the extent of thermal evolution and ash yield jointly constrain the heterogeneity of pore size distribution.In mediumto high-ash yield coal seams,the heterogeneity of pore structure and pore size distribution are predominantly constrained by ash yield.(2)As the ash yield vertically increases,the mesoporous pore volume and specific surface area initially decrease and subsequently increase,while the contribution of micropores to both pore volume and specific surface area continuously diminishes.Consequently,the total pore volume and specific surface area of the coal samples exhibit a two-stage reduction close to an ash yield threshold of approximately 20%.(3)Further,the Langmuir volume for CH_(4)adsorption sharply declines below the 20%threshold,followed by a gradual decrease;in contrast,the Langmuir pressure initially decreases and subsequently increases.Hence,the vertical increase in ash yield constrains the development of pore systems and diminishes pore connectivity,thereby reducing methane adsorption capacity and adversely affecting coalbed methane productivity.(4)Low-ash yield coal reservoirs are characterized by a rapid gas breakthrough and high productivity,whereas medium-ash yield coal reservoirs generally require prolonged depressurization to achieve peak gas production.These findings reveal that in medium-high rank coal,ash yield―and not thermal evolution―is the main factor that controls vertical pore evolution and methane adsorption efficiency.The quantitative ash yield threshold(20%)established in this study provides a practical criterion for evaluating reservoir quality and predicting vertical variations in gas storage potential in the Ordos Basin.
基金supported by the National Natural Science Foundation of China (Grant Nos.42075097,42177081 and 22176037)。
文摘As a key precursor of hydroxyl(OH) radicals, the budget of nitrous acid(HONO) at different altitudes has received extensive attention. In this study, vertically resolved observations of HONO, NO_(2), O_(3), and HCHO were conducted during an autumn field campaign in Beijing in 2019. The significant correlation between HONO and NO2, along with variations in their ratios across different altitudes, underscores the importance of aerosol surface chemistry in HONO formation and its altitude-dependent behavior. To enhance the model performance, the heterogeneous conversion of NO_(2) and its photochemical enhancement are incorporated into the 1D model. The simulations reveal that the nocturnal HONO production is dominated by the heterogeneous conversion of NO_(2) both at the surface and aloft. During the daytime, groundsurface sources of HONO are mainly driven by nitrate photolysis and light-enhanced heterogeneous conversion of NO_(2).Meanwhile, a large portion of the HONO generated at the surface is transported upwards through vertical mixing. In the higher atmosphere, HONO originates from vertical transport and in situ processes. As precursors of OH radicals, the observed concentrations of HONO, O_(3), and HCHO exhibit distinct diurnal variations and vertical distribution patterns.HONO contributes to OH radical production predominantly during the early morning across all layers and it even becomes the main contributor throughout the daytime in the lowest layer near the ground, while O_(3) and HCHO become more prominent towards midday, especially in the higher layers. These results will be beneficial for a deeper understanding of the atmospheric oxidation process within the urban boundary layer.
基金supported by the National Natural Science Foundation of China(Grant No.52379097)the National Natural Science Foundation of China(No.52509138)+2 种基金the Water Conservancy Science and Technology Project of Jiangxi Province(Grant No.202426ZDKT27)Chongqing Natural Science Foundation Doctoral Program(CSTB2025NSCQ-BSX0020)the Research and Innovation Program for Graduate Students of Chongqing Municipality(Grant No.CYB23251).
文摘Quantifying spatial heterogeneity in soil water retention properties(SWRP)is crucial for enhancing the accuracy of hydrogeological simulations.However,studies on the spatial heterogeneity of SWRP in the Chinese Loess Plateau(CLP)remain scarce,especially at the vertical scale.We conducted laboratory tests on undisturbed loess cores collected from boreholes in CLP to analyze soil physical parameters(SPPs)and SWRP.Measured soil water characteristic curves(SWCCs)were fitted to the Brooks-Corey(BC),Fredlund-Xing(FX),and van Genuchten(vG)models.It was revealed that the FX and vG models outperformed the BC model.The geostatistical analysis identified the Gaussian model as optimal for describing the semivariograms of both SPPs and SWCC fitting parameters(FPs).Strikingly,over 90%of these parameters exhibited strong vertical spatial dependence,with an average autocorrelation length of 213.878 cm for SPPs and 320.678 cm for FPs.Moreover,SWRP was found to be significantly influenced by both SPPs and the vertical position relative to the loess ridge slope surface.Parameters near the ridge slope surface showed significantly degraded spatial dependence.These findings provide valuable insights for parameterizing the spatial heterogeneity of soil water retention properties,which are beneficial for hydrogeological modelling in shallow CLP loess strata.
基金Project supported by the Guangdong Basic and Applied Basic Research Foundation of China(Nos.2022B1515020099 and 2024A1515240026)the National Natural Science Foundation of China(No.12372147)the Fundamental Research Funds for the Central Universities of China(No.HIT.OCEF.2024019)。
文摘Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical crack under combined mechanical and electric loading,considering both central and edge cracks.Using Fourier transforms and dislocation density functions,the Mode-Ⅲproblem is converted to Cauchy-type singular integral equations.The crack surface fields,intensity factors,and energy release rate are derived.The accuracy of the proposed model is verified through the finite element(FE)simulation via COMSOL Multiphysics.The results for low electron concentrations align with those of the intrinsic piezoelectric materials,validating the correctness of the present model as well.The combined effects of crack position,applied electric loading,and initial carrier concentration on the crack propagation are analyzed.The normalized electric displacement factor shows heightened sensitivity to crack size,electromechanical loading,and carrier concentration.The crack position significantly influences the crack surface fields and normalized intensity factors due to the boundary proximity effect.
基金National Natural Science Foundation of China(42274012,42004001)the Science and Technology Innovation Project of Anhui Surveying and Mapping Bureau(2025-KJ-08)+1 种基金the Open Fund of Wuhan Gravitation and Solid Earth Tides,National Observation and Research Station(WHYWZ202107)the Fundamental Research Funds for the Central Universities(JZ2022HGTB0268)。
文摘To characterize the spatial patterns of vertical crustal movement of Chinese mainland,GNSS imaging technology was applied to map the tectonic deformation of the region.In this study,the vertical crustal velocities inferred from GNSS data for Chinese mainland over two decades were rigorously estimated.First,by analyzing the vertical displacement time series from continuous GNSS stations and environmental load data,we found that the annual and semi-annual vertical displacements are highly correlated.This indicates that the vertical seasonal variations on the ground surface are mainly caused by environmental loading.After removing the seasonal variations caused by environmental loads from the GNSS time series,we applied an improved PCA technique to filter out common mode errors.Next,we estimated the optimal noise models for the filtered time series and derived the vertical velocity field of Chinese mainland.Finally,we employed an empirical Spatial Structure Function(SSF)to image the tectonic deformation of Chinese mainland.This method effectively mitigates issues with abrupt circular arc-shaped boundaries in GNSS imaging caused by sparse station networks.The imaging results show that vertical crustal deformation in Chinese mainland generally ranges from-3 to 3 mm/yr,with significant spatial variability.The central and northern parts of Qinghai-Xizang Plateau are identified as primary subsidence zones,indicating that plate boundaries and tectonic compression continue to shape the crustal movement in these regions.The major uplift zones are located in northern and central China,likely linked to regional tectonic activity and plate compression.Subsidence deformation in parts of eastern China appears to be influenced by human activities.
基金supported by the National Natural Science Foundation of China(No.U2333214).
文摘As the frontier of multidimensional transportation systems,urban air mobility(UAM)is receiving increasing attention from international organizations,governments,and stakeholders in industry and academia owing to its high efficiency,low carbon footprint,and operational flexibility.Vertical take-off and landing(VTOL)infrastructure is the core facility that enables UAM and is therefore essential for its safe,efficient,and large-scale commercial implementation.However,the key technologies for establishing low-altitude VTOL infrastructure are still nascent,and government,industry,and academia have yet to harmonize the corresponding construction,management,and operation standards.To address this gap,we herein systematically review the related progress and trends,comprehensively surveying the key technologies of establishing VTOL infrastructure serving unmanned aerial vehicles(UAVs)and electric VTOL aircraft from three complementary perspectives of ground-side,airspace-side,and communication,navigation,surveillance,and information services.In the light of future UAM operations characterized by diverse vehicle types and dense air traffic,we propose a conceptual design for a public multioperator VTOL site to provide constructive insights into the sustainable growth of the low-altitude economy.
基金supported by Systematic Major Project of Shuohuang Railway Development Co.,Ltd.,National Energy Group(Grant Number:SHTL-23-31)Beijing Natural Science Foundation(U22B2027).
文摘In the realm of Intelligent Railway Transportation Systems,effective multi-party collaboration is crucial due to concerns over privacy and data silos.Vertical Federated Learning(VFL)has emerged as a promising approach to facilitate such collaboration,allowing diverse entities to collectively enhance machine learning models without the need to share sensitive training data.However,existing works have highlighted VFL’s susceptibility to privacy inference attacks,where an honest but curious server could potentially reconstruct a client’s raw data from embeddings uploaded by the client.This vulnerability poses a significant threat to VFL-based intelligent railway transportation systems.In this paper,we introduce SensFL,a novel privacy-enhancing method to against privacy inference attacks in VFL.Specifically,SensFL integrates regularization of the sensitivity of embeddings to the original data into the model training process,effectively limiting the information contained in shared embeddings.By reducing the sensitivity of embeddings to the original data,SensFL can effectively resist reverse privacy attacks and prevent the reconstruction of the original data from the embeddings.Extensive experiments were conducted on four distinct datasets and three different models to demonstrate the efficacy of SensFL.Experiment results show that SensFL can effectively mitigate privacy inference attacks while maintaining the accuracy of the primary learning task.These results underscore SensFL’s potential to advance privacy protection technologies within VFL-based intelligent railway systems,addressing critical security concerns in collaborative learning environments.
文摘To improve the current grinding procedure of the back-up roll of CVC hot rolling mills so that the back-up roll service life can be extended, the crack initiation and propagation behavior of medium carbon bainitic back-up roll steel was investigated, a kind of asperity-scale, surface originated vertical short cracks occurred at 5 × 10^2 -1 × 10^4 cycles. Theoretical analysis indicated that the maximum tensile stress occurring at the back edge of the contact of asperities keeps at above 1 347. 97 MPa, and ratcheting and cyclic plastic deformation take place at such sites within 1 × 10^4 cycles. The early initiation of the vertical short cracks is caused by the asperity contact. According to the crack initiation mechanism, short crack behavior and preventive grinding strategy, steel consumption can be reduced considerably by decreasing the surface roughness and removing the asperity influenced surface thin layer at about 70%-80% of the surface distress life.
基金supported by the Key Project of Chinese Academy of Sciences under grant KZCX2-YW-217the National Natural Science Foundation of China (40830103)+1 种基金supported by NSF (ATM0634762)NOAA (NA07NES4400002)
文摘One deficiency of the NCAR Community Land Model （CLM3） is the disappearance of the simulated snow even in the middle of winter over a boreal grassland site due to unrealistically modeled high downward turbulent fluxes. This is caused by the inappropriate treatment of the vertical snow burial fraction for short vegetation. A new snow burial fraction formulation for short vegetation is then proposed and validated using in situ observations. This modification in the CLM3 largely removes the unrealistic surface turbulent fluxes, leading to a more reasonable snowmelt process, and improves the snow water equivalent （SWE） simulation. Moreover, global offline simulations show that the proposed formulation decreases sensible and latent heat fluxes as well as the ground temperature during the snowmelt season over short vegetation dominant regions. Correspondingly, the SWE is enhanced, leading to the increase in snowmelt-induced runoff during the same period. Furthermore, sensitivity tests indicate that these improvements are insensitive to the exact functional form or parameter values in the proposed formulation.
基金funded by the National Key R&D Program of China(No.2017YFC1500202)supported by the National Natural Science Foundation of China(No.41604048)China Earthquake Science Experiment(No.2016CESE0103)
文摘The influence of local site effects on seismic ground motions is an important issue in seismic hazard assessment and earthquake resistant design. Determining site effects in densely populated cities built on basins can help to reduce the earthquake hazard. Site effects of Luoyang basin are estimated by the horizontal-to-vertical spectral ratio(HVSR) method using ambient noise records from a short-period dense array. The sites in Luoyang basin are sorted into three types according to the pattern of the HVSR curves. There are cases with a single clear peak, two clear peaks, and an unclear low frequency peak or multiple peaks, which correspond to there being one large impedance contrast interface, two large interfaces, and a moderate one beneath the sites, respectively. The site effects characterized by fundamental frequency from HVSR curves are affected by underlying sedimentary layers and depth of sedimentary basement. According to our results, the existence of thick sediment layer obviously lowers the fundamental frequency to the period range from 2 to 4 s in the downtown area of Luoyang city. The ground motion will amplify when through the sites and the buildings with height of 20–50 floors can resonate at the similar frequency domain. Site effects estimation using HVSR method from a short-period dense array is an effective technique in areas of moderate seismic risk where strong motion recordings are lacking, such as the Luoyang basin.
基金Project(2022YJS073)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2024YFE0198500)supported by the National Key Research and Development Program of China:Intergovernmental International Science and Technology Innovation CooperationProject(U2469207)supported by the National Natural Science Foundation Railway Innovation and Development Joint Fund Project,China。
文摘Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.
基金supported by National Key Research and Development Program of China,China(2024YFD1800102,2022YFD1800105 and 2022YFD1801500)National Natural Science Foundation of China,China(32372993 and 32030107)Fundamental Research Funds for the Central Universities,China(2662023PY005).
文摘Zika virus(ZIKV)is a mosquito-borne virus belonging to the genus Orthoflavivirus,and the family Flaviviridae.It commonly presents with febrile-like symptoms,neurological issues,and pregnancy complications in humans.Currently,there is no commercial vaccine or specific treatment available to prevent ZIKV infection.Therefore,controlling the epidemic's spread relies on preventing mosquitoes from transmitting the virus.Although various studies have explored the transmission of ZIKV between mosquitoes and vertebrate hosts,comprehensive research on potential mosquito-to-mosquito transmission of ZIKV remains limited.In this study,we conducted systematic laboratory investigations to assess the ability of ZIKV to spread among mosquitoes,and to evaluate the impact of ZIKV infection on mosquito development.Our findings revealed that ZIKV can be transmitted between Aedes aegypti mosquitoes both vertically and horizontally,through oviposition and contact between mosquitoes of the same or opposite sex.Additionally,we observed that ZIKV infection resulted in a reduction in the number of mosquito eggs but an increase in their size.The widespread distribution of ZIKV in infected mosquitoes and the altered levels of hormone related genes following viral infection were noted,which may contribute to viral transmission among mosquitoes and affect mosquito development.This research provides systematic experimental evidence of ZIKV transmission among mosquitoes,which is crucial for developing novel strategies to disrupt the spread of orthoflaviviruses and other mosquitoborne pathogens.
基金supported by the National Natural Science Foundation of China(Nos.42022051,U21A2028,and 42305124)the Youth Innovation Promotion Association CAS(No.Y202089)the HFIPS Director’s Fund(Nos.BJPY2023A02,YZJJ202101,and YZJJ2023QN01).
文摘Vertical detection of volatile organic compounds(VOCs)is essential to expend our understanding of the distribution characteristics of VOCs and improve the predictive ability of existing air qualitymodels.In this work,we report the development of a sorbent tube sampler based on an unmanned aerial vehicle(UAV)platform.Vertical profile measurement of VOCs with a vertical resolution of 25mwas achieved.The sampler consists of five lightweight VOC sorbent tubes and a 5-way solenoid valve,making it available for collecting five atmospheric VOC samples in a single flight with a time response of less than 30min.The samplerweighed∼1.45 kg and had dimensions of 240mm×220mm×100mmwith small penetration loss(<10%)under 4-liter sampling conditions(flow rate of 200 mL/min).Commercialized SUMMA canisters were used as experimental controls to investigate the possible loss of self-made sampler for target compounds in the same sampling process.Comparison experiment on the ground showed that the concentration differences for all VOC species were lower than 0.14μg/m3,proving the good reliability for VOCs measurements using sorbent tube sampler.The UAV platform also incorporated online instruments for meteorological parameters and O_(3) measurement.The sampler was successfully applied to characterize the vertical profiles of VOCs up to 100 m in October 2023 in the Huaihe River Basin of China.The UAV platform and the sorbent tube sampler demonstrate good performance and will be a valuable and reliable tool for vertical VOCs measurement.
基金the National Research Foundation(NRF),Prime Minister’s Office,Singapore,under its Campus for Research Excellence and Technological Enterprise(CREATE)program(A-0001032-01-00)the National Natural Science Foundation of China(52376011).
文摘The increasing population and continuous urbanization make food security a key consideration in sustainable development.Efficient farming strategies with low environmental footprints are thus increasingly required to meet food demands.This study presents a design for environmentally friendly,economical,and modular vertical farming systems,in which vegetables are cultivated in a carbon dioxide(CO_(2))-enriched atmosphere enabled by direct air capture(DAC)and subjected to artificial light exposure.We established a vertical farming setup and conducted experiments to identify productive cultivation strategies by regulating lighting,CO_(2)concentration,biochar application,and plant species.Additionally,a self-developed DAC rotary adsorber was utilized to achieve stable and efficient CO_(2)enrichment.Compared with the control group,the fresh weight of the vegetables in the experimental groups increased by up to 57.5%.Furthermore,we performed a comprehensive evaluation of the design and demonstrated that integrating photovoltaic-thermal(PVT)and DAC units increased the system’s net present value(NPV)by 157%compared with a conventional design without these units.Importantly,we found it possible to maintain the low carbon footprint of the system(0.468 kg-CO_(2)equivalent·kg−1(CO_(2)eq·kg−1)-vegetable)in the production process.Parametric studies and an application analysis on a global scale reveal the wide adaptability of this strategy to diverse conditions.These findings,together with the modular characteristics of vertical farming systems,highlight the promising potential of this design to increase food security and foster sustainable agriculture.
