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 restore dam-blocked natural fish migratory passages,a growing number of artificial fishways have been built in water conservancy and hydropower projects in China.The Angu hydropower station involved diverse importa...To restore dam-blocked natural fish migratory passages,a growing number of artificial fishways have been built in water conservancy and hydropower projects in China.The Angu hydropower station involved diverse important fish habitats in the lower reaches of the Daduhe River in Southwest China.Therefore,a vertical slot fishway(VSF)and a nature-like fishway(NLF)were built near the backwater area of the reservoir to connect the upstream and downstream habitats.Hydrodynamic and aquatic ecological surveys were conducted after the completion of the project to estimate the fish passing effect of the two fishways.The results indicated that both fishways were in effective operation and could maintain the desired hydrodynamic conditions and be used by several local fish species.During the survey,149 fish from 15 species and 111 fish from 17 species were captured by the traps in the VSF and NLF,respectively,while 1263 fish from 27 species were found in the downstream area.Some species captured in the VSF were not found in the NLF,and vice versa,which implied the different preferences of fish.Meanwhile,3789 signals including 2099 upward ones and 1690 downward ones were monitored with an ultrasonic fish detector at the inlet of the VSF.These findings revealed the characteristics of fish species observed in and near the fishways and provided valuable insights into the different fish passing capabilities of VSFandNLF.展开更多
To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid d...To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid dynamics(CFD)analysis.First,a CFD analysis of a two-bladed VAWT equipped with a NACA 0012 airfoil is conducted.The thrust and power coefficients are validated through experiments.Second,the blade force and velocity data at monitoring points are collected.The AOA at different azimuth angles is determined by removing the blade self-induction at the monitoring point.Then,the lift and drag coefficients as a function of AOA are extracted.Results show that this method is independent of the monitoring points selection located at certain distance to the blades and the extracted dynamic stall hysteresis is more precise than the one with the“usual”method without considering the self-induction from bound vortices.展开更多
The Zenith Hydrostatic Delay(ZHD)is essential for high-precision Global Navigation Satellite System(GNSS)and Very Long Baseline Interferometry(VLBI)data processing.Accurate estimation of ZHD relies on in situ atmosphe...The Zenith Hydrostatic Delay(ZHD)is essential for high-precision Global Navigation Satellite System(GNSS)and Very Long Baseline Interferometry(VLBI)data processing.Accurate estimation of ZHD relies on in situ atmospheric pressure,which is primarily variable in the vertical direction.Current atmospheric pressure is either site-specific or has limited spatial coverage,necessitating vertical corrections for broader applicability.This study introduces a model that uses a Gaussian function for the vertical correction of atmospheric pressure when in situ meteorological observations are unavailable.Validation with the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis(ERA5)reveals an average Bias and RMS for the new model of 0.31 h Pa and 2.96 h Pa,respectively.This corresponds to improvements of 37.5%and 80.3%in terms of RMS compared to two commonly used models(T0and Tvmodels)that require in situ meteorological observations,respectively.Additional validation with radiosonde data shows an average Bias and RMS of 1.85 h Pa and 4.87 h Pa,corresponding to the improvement of 42.8%and 71.1%in RMS compared with T0and Tv models,respectively.These accuracies are sufficient for calculating ZHD to an accuracy of 1 mm by performing atmospheric pressure vertical correction.The new model can correct atmospheric pressure from meteorological stations or numerical weather forecasts to different heights of the troposphere.展开更多
van der Waals(vdW)heterostructures constructed by lowdimensional(0D,1D,and 2D)materials are emerging as one of the most appealing systems in next-generation flexible photodetection.Currently,hand-stacked vdW-type phot...van der Waals(vdW)heterostructures constructed by lowdimensional(0D,1D,and 2D)materials are emerging as one of the most appealing systems in next-generation flexible photodetection.Currently,hand-stacked vdW-type photodetectors are not compatible with large-areaarray fabrication and show unimpressive performance in self-powered mode.Herein,vertical 1D GaN nanorods arrays(NRAs)/2D MoS_(2)/PEDOT:PSS in wafer scale have been proposed for self-powered flexible photodetectors arrays firstly.The as-integrated device without external bias under weak UV illumination exhibits a competitive responsivity of 1.47 A W^(−1)and a high detectivity of 1.2×10^(11)Jones,as well as a fast response speed of 54/71μs,thanks to the strong light absorption of GaN NRAs and the efficient photogenerated carrier separation in type-II heterojunction.Notably,the strain-tunable photodetection performances of device have been demonstrated.Impressively,the device at−0.78%strain and zero bias reveals a significantly enhanced photoresponse with a responsivity of 2.47 A W^(−1),a detectivity of 2.6×10^(11)Jones,and response times of 40/45μs,which are superior to the state-of-the-art self-powered flexible photodetectors.This work presents a valuable avenue to prepare tunable vdWs heterostructures for self-powered flexible photodetection,which performs well in flexible sensors.展开更多
The Michelson Interferometer for Global High-resolution Thermospheric Imaging(MIGHTI)onboard the Ionospheric Connection Explorer(ICON)satellite offers the opportunity to investigate the altitude profile of thermospher...The Michelson Interferometer for Global High-resolution Thermospheric Imaging(MIGHTI)onboard the Ionospheric Connection Explorer(ICON)satellite offers the opportunity to investigate the altitude profile of thermospheric winds.In this study,we used the red-line measurements of MIGHTI to compare with the results estimated by Horizontal Wind Model 14(HWM14).The data selected included both the geomagnetic quiet period(December 2019 to August 2022)and the geomagnetic storm on August 26-28,2021.During the geomagnetic quiet period,the estimations of neutral winds from HWM14 showed relatively good agreement with the observations from ICON.According to the ICON observations,near the equator,zonal winds reverse from westward to eastward at around 06:00 local time(LT)at higher altitudes,and the stronger westward winds appear at later LTs at lower altitudes.At around 16:00 LT,eastward winds at 300 km reverse to westward,and vertical gradients of zonal winds similar to those at sunrise hours can be observed.In the middle latitudes,zonal winds reverse about 2-4 h earlier.Meridional winds vary more significantly than zonal winds with seasonal and latitudinal variations.According to the ICON observations,in the northern low latitudes,vertical reversals of meridional winds are found at 08:00-13:00 LT from 300 to 160 km and at around 18:00 LT from 300 to 200 km during the June solstice.Similar reversals of meridional winds are found at 04:00-07:00 LT from 300 to 160 km and at 22:00-02:00 LT from 270 to 200 km during the December solstice.In the southern low latitudes,meridional wind reversals occur at 08:00-11:00 LT from 200 to 160 km and at 21:00-02:00 LT from 300 to 200 km during the June solstice.During the December solstice,reversals of the meridional wind appear at 20:00-01:00 LT below 200 km and at 06:00-11:00 LT from 300 to 160 km.In the northern middle latitudes,the northward winds are dominant at 08:00-14:00 LT at 230 km during the June solstice.Northward winds persist until 16:00 LT at 160 and 300 km.During the December solstice,the northward winds are dominant from 06:00 to 21:00 LT.The vertical variations in neutral winds during the geomagnetic storm on August 26-28 were analyzed in detail.Both meridional and zonal winds during the active geomagnetic period observed by ICON show distinguishable vertical shear structures at different stages of the storm.On the dayside,during the main phase,the peak velocities of westward winds extend from a higher altitude to a lower altitude,whereas during the recovery phase,the peak velocities of the westward winds extend from lower altitudes to higher altitudes.The velocities of the southward winds are stronger at lower altitudes during the storm.These vertical structures of horizontal winds during the storm could not be reproduced by the HWM14 wind estimations,and the overall response to the storm of the horizontal winds in the low and middle latitudes is underestimated by HWM14.The ICON observations provide a good dataset for improving the HWM wind estimations in the middle and upper atmosphere,especially the vertical variations.展开更多
This article presents four techniques for assessing verticality:the plumb line approach,the total station distance technique,the three-point centering method,and the centroid method.Given the significant error associa...This article presents four techniques for assessing verticality:the plumb line approach,the total station distance technique,the three-point centering method,and the centroid method.Given the significant error associated with the total station horizontal distance technique when measuring circular piers,this paper proposes the centroid method.This method calculates verticality by determining the coordinates of the center points at both ends of the pier.Experimental findings indicate that the centroid method achieves accuracy in measuring the verticality of circular piers comparable to the three-point centering method,while offering a faster inspection process.Furthermore,the paper explores the concept of composite verticality and validates the effectiveness of the centroid method in measuring composite verticality and its practical applications through comparative experiments.展开更多
Airborne area-array whisk-broom imaging systems typically adopt constant-speed scanning schemes.For large-inertia scanning systems,constant-speed scanning requires substantial time to complete the reversal motion,redu...Airborne area-array whisk-broom imaging systems typically adopt constant-speed scanning schemes.For large-inertia scanning systems,constant-speed scanning requires substantial time to complete the reversal motion,reducing the system's adaptability to high-speed reversal scanning and decreasing scanning efficiency.This study proposes a novel sinusoidal variable-speed roll scanning strategy,which reduces abrupt changes in speed and acceleration,minimizing time loss during reversals.Based on the forward image motion compensation strategy in the pitch direction,we establish a line-of-sight(LOS)position calculation model with vertical flight path correction(VFPC),ensuring that the central LOS of the scanned image remains stable on the same horizontal line,facilitating accurate image stitching in whisk-broom imaging.Through theoretical analysis and simulation experiments,the proposed method improves the scanning efficiency by approximately 18.6%at a 90o whiskbroom imaging angle under the same speed height ratio conditions.The new VFPC method enables wide-field,high-resolution imaging,achieving single-line LOS horizontal stability with an accuracy of better than O.4 mrad.The research is of great significance to promote the further development of airborne area-array whisk-broom imaging technology toward wider fields of view,higher speed height ratios,and greater scanning efficiency.展开更多
Plastic pollution and microplastics in sediments are a growing concern for marine ecosystems worldwide.We examined the vertical distribution and properties of microplastics in beach sediments of Xuwen Coral Reef Natio...Plastic pollution and microplastics in sediments are a growing concern for marine ecosystems worldwide.We examined the vertical distribution and properties of microplastics in beach sediments of Xuwen Coral Reef National Nature Reserve,in Leizhou Peninsula,Zhanjiang,China.Sediment samples were taken in seven locations at 5-cm intervals from the surface to a depth of 30 cm.The vertical distribution of microplastic particles ranged from 0 to 1340 particles per kg on average of 119.05particles per kg.The most prevalent material was fibers(76%),followed by film(12%),fragments(11.2%),and foam(0.8%).The microplastics in size of 1-2 mm constituted the largest percentage(40%)of the total,followed by those in size of<1 mm(26.4%),2-3 mm(21.2%),3-4 mm(9.6%),and 4-5 mm(2.81%).Site S1 observed maximum sizes between 1 and 2 mm,S2 reported higher availability of microplastics with sizes ranging from 0.3 to 1 mm.Six different types of polymers were identified in the investigation,and mostly were polyethylene(PE)and polypropylene(PP).In general,the observation of microplastics in deeper sediments indicates that they have the ability to last for prolonged periods in the marine environment,which may present long-term hazards to benthic creatures.In conclusion,the discovery of microplastics in deep layers of coastal sediments highlights the necessity of minimizing plastic waste and enhancing management strategies to safeguard marine environments.展开更多
Using observations and models from phase 6 of the Coupled Model Intercomparison Project(CMIP6),this study analyzes the performance of CMIP6 models in simulating the vertical structure of the Quasi-Biennial Oscillation...Using observations and models from phase 6 of the Coupled Model Intercomparison Project(CMIP6),this study analyzes the performance of CMIP6 models in simulating the vertical structure of the Quasi-Biennial Oscillation(QBO)and its impacts on eastern China surface air temperature(SAT),with empirical orthogonal function(EOF)analysis.The first leading mode(EOF1)of the QBO leads to an overall cooling/warming over eastern China via the QBO’s subtropical path and Holton-Tan effect,while the second leading mode(EOF2)of the QBO tends to cause an east-west dipole of SAT anomalies between eastern and western China due to a strong Holton-Tan effect.Most models with a self-generated QBO can capture both westerly and easterly QBO anomalies in the mid-lower stratosphere in EOF1 and only westerly anomalies in EOF2.The multi-model ensemble mean can reproduce the eastern China SAT anomalies that are statistically significant and related to EOF1-like QBO events.However,the intensity of these anomalies is relatively weaker,attributable to the weak Pacific response to the subtropical effect of the QBO.In contrast,most models fail to induce a strong Holton-Tan effect and a Northern Annular Mode pattern in the polar region during the EOF2-like QBO events,resulting in weak and insignificant eastern China SAT anomalies on average.Overall,the models with a better representation of polar and Pacific responses to the QBO’s vertical structure exhibit a more reasonable eastern China SAT response,although such a response is weaker than observed.展开更多
In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module ...In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module has 30%higher power generation,especially in desert photovoltaic(PV)with a bimodal distribution.While the south-north one has a single peak,the same as normal PV modules.Vertical power generation technology of HJT also has less land occupation,which is of great significance for optimizing the design of photovoltaic systems.展开更多
Cadmium telluride(CdTe),which has a high average atomic number and a unique band structure,is a leading material for room-temperature X/γ-ray detectors.Resistivity and mobility are the two most important properties o...Cadmium telluride(CdTe),which has a high average atomic number and a unique band structure,is a leading material for room-temperature X/γ-ray detectors.Resistivity and mobility are the two most important properties of detector-grade CdTe single crystals.However,despite decades of research,the fabrication of high-resistivity and high-mobility CdTe single crystals faces persistent challenges,primarily because the stoichiometric composition cannot be well controlled owing to the high volatility of Cd under high-temperature conditions.This volatility introduces Te inclusions and cadmium vacancies(V_(Cd))into the as-grown CdTe ingot,which significantly degrades the device performance.In this study,we successfully obtained detector-grade CdTe single crystals by simultaneously employing a Cd reservoir and chlorine(Cl)dopants via a vertical gradient freeze(VGF)method.By installing a Cd reservoir,we can maintain the Cd pressure under the crystal growth conditions,thereby preventing the accumulation of Te in the CdTe ingot.Additionally,the existence of the Cl dopant helps improve the CdTe resistivity by minimizing V_(Cd)density through the formation of an acceptor complex(Cl_(Te)-V_(Cd))^(-1).The crystalline quality of the obtained CdTe(Cl)was evidenced by a reduction in large Te inclusions,high optical transmission(60%),and a sharp absorption edge(1.456 eV).The presence of substitutional Cl dopants,known as Cl_(Te)^(+),simultaneously supports the record high resistivity of 1.5×10^(10)Ω·cm and remarkable electron mobility of 1075±88 cm^(2)V^(-1)s^(-1)simultaneously,has been confirmed by photoluminescence spectroscopy.Moreover,using our crystals,we fabricated a planar detector withμτ_(e)of(1.11±0.04)×10^(-4)cm^(2)∕V,which performed with a decent radiation-detection feature.This study demonstrates that the vapor-pressure-controlled VGF method is a viable technical route for fabricating detector-grade CdTe crystals.展开更多
Ball-sealer plugging is a cost-effective method for hydraulic fracturing in vertical wells,yet the transport and plugging behavior of ball sealers remains poorly understood.This paper investigates ball-sealer plugging...Ball-sealer plugging is a cost-effective method for hydraulic fracturing in vertical wells,yet the transport and plugging behavior of ball sealers remains poorly understood.This paper investigates ball-sealer plugging using both experimental and numerical approaches.A coupled computational fluid dynamics(CFD) and discrete element method(DEM) model simulates ball transport under field conditions,validated by experiments in inclined pipes.Results show that plugging performance improves with a higher flow rate ratio of the perforation,allowing effective plugging even when the ball is far from the target perforation.There exists a threshold distance between the ball and the perforation under specific conditions.The closer the ball is to the wellbore wall,the higher the likelihood of successful plugging.Low-density balls can enhance plugging performance to some extent.At high flow rates,ball inertia along the wellbore axis increases,reducing the ball's ability to redirect and weakening plugging performance.Ball interactions also affect their positioning and plugging success.In vertical wells with multiple clusters,prioritizing higher flow rates to the first fracturing cluster optimizes overall plugging performance and minimizes excessive plugging in lower,under-stimulated clusters.These findings offer valuable insights for optimizing ball-sealer deployment in well completions,improving operational outcomes.展开更多
As complex and diverse ecosystems,cities encounter numerous challenges posed by both nature and humanity.Architecture,serving as the framework and texture of the city,has undoubtedly emerged as a crucial guide in addr...As complex and diverse ecosystems,cities encounter numerous challenges posed by both nature and humanity.Architecture,serving as the framework and texture of the city,has undoubtedly emerged as a crucial guide in addressing urban resilience issues.Roof greening and vertical greening of buildings,as ecofriendly urban green infrastructures,hold significant potential for mitigating these challenges.This paper explores the methods and strategies for implementing roof greening and vertical greening as solutions to enhance urban resilience.The objective is to offer valuable insights for sustainable urban development,encourage the widespread adoption of these greening techniques in urban construction,and ultimately strengthen urban resilience.展开更多
Objectives:Sea sickness, a form of motion sickness, is a common condition among sailors on various sailing vessels, primarily due to their roll and pitch movements. While the exact neurobiological mechanisms remain un...Objectives:Sea sickness, a form of motion sickness, is a common condition among sailors on various sailing vessels, primarily due to their roll and pitch movements. While the exact neurobiological mechanisms remain unclear, the most widely accepted explanation is the sensory conflict theory,which identifies two main sources of conflict: discrepancies between visual and vestibular inputs and conflicts within the vestibular system itself.This study aims to evaluate otolith-mediated verticality perception in first-time seafarers on board a naval frigate ship using the Subjective Visual Vertical(SVV) test.Methods:This observational study was conducted on board a naval frigate and involved two groups. The case group consisted of50 newly recruited sailors experiencing their first sea voyage. The SVV test was conducted at three time points: prior to embarkation, during an active episode of sea sickness, and after disembarkation. A control group of 50 healthy, experienced sailors-regular seafarers with no history of vestibular symptoms underwent the same SVV testing at corresponding intervals. The results from both groups were collected and analyzed to assess changes in verticality perception related to sea exposure and sea sickness.Results:Analysis of the SVV test data from the 50 newly recruited sailors(case group) demonstrated a statistically significant difference compared to the control group of experienced sailors. During an active episode of sea sickness, the case group exhibited a notable tilt and deviation in SVV angles, indicating altered verticality perception. These deviations reduced significantly 24 hours post-disembarkation, suggesting an improvement in verticality perception once the motion stimulus was removed.Conclusion:This distinctive study assessed otolith-mediated verticality perception using the SVV test in first-time seafarers experiencing sea sickness aboard a naval frigate. Our findings emphasize the functional importance of the otolith organs in maintaining spatial orientation during maritime motion exposure. The observed SVV deviations support the subjective vertical conflict theory, highlighting the role of vestibular-visual mismatch in the development of sea sickness. However, our findings more likely reflect transient functional disturbance or overstimulation rather than a pre-existing utricular asymmetry alone. Based on the pattern of SVV deviation and recovery, we propose that the utricle may play a more significant role than the saccule in inducing sea sickness.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
This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-s...This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-source software Open FOAM~?, a two-dimensional viscous-flow numerical wave flume was developed to simulate the fluid resonant motions induced by transient focused wave groups with different spectral peak periods and wave amplitudes. The results indicate that for all the incident focused wave amplitudes considered, the amplitudes of the free surface elevation in the gap, horizontal wave force and moment all exhibit a bimodal variation trend with increasing spectral peak period. The peak values of the above amplitude-period curve appear near the resonant period of the first and second harmonic components of the free surface elevation. However, the variation in the vertical wave force versus the spectral peak period presents different patterns. In addition, the first-to fourth-order harmonic components in the wave surface and forces are further examined via the four-phase combination method. The results show that the first-to secondorder harmonic components play a dominant role in the overall amplitude.展开更多
The diversity of interlayers in shale oil reservoir leads to a low degree of vertical reconstruction.This paper aims to propose a method to guide the synchronous initiation of hydraulic fractures in different layers b...The diversity of interlayers in shale oil reservoir leads to a low degree of vertical reconstruction.This paper aims to propose a method to guide the synchronous initiation of hydraulic fractures in different layers by drilling multi-layer radial wells in spatial positions,and to form a fracture network that satisfies the vertical propagation range and complexity.In this paper,a 3D(three-dimensional)multi-layer radial well fracturing model considering fluid-mechanics coupling is established and the properties of shale oil reservoir are characterized according to the field geological profile.The influences of radial well spacing,fracturing fluid injection rate,and fracturing fluid viscosity on vertical fracture communication in multilayer radial wells are investigated.The results show that the radial well has the characteristics of guiding fracture penetrating interlayers.Reducing radial well spacing and appropriately increasing injection rate and viscosity are beneficial to improving vertical fracture propagation ability.However,high fracture fluid viscosity under the same displacement will lead to a significant increase in fracture aperture and weaken the total fracture area.In addition,if the stress interference around the radial wells is low,the radial well can be located in the middle of each layer to minimize the fracture height limitation.This study can provide a solution idea for vertical propagation limitation of hydraulic fractures in shale oil reservoir.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
Reservoirs play a critical role in addressing water resources challenges.However,their vertical influence on the assembly mechanisms of different microbial communities,including prokaryotes and eukaryotes,remains uncl...Reservoirs play a critical role in addressing water resources challenges.However,their vertical influence on the assembly mechanisms of different microbial communities,including prokaryotes and eukaryotes,remains unclear.This study examined the vertical diversity patterns of abundant and rare subcommunities of prokaryotes and eukaryotes in an urban reservoir,using water depth as a geographical gradient and employing high-throughput sequencing.The impact of vertical environmental heterogeneity on community structure was quantified,and key drivers of these dynamics were identified.The results indicated that the urban reservoir exhibited statistically significant differences in the vertical distribution of water temperature and oxidation/reduction potential.The a-diversity of the abundant subcommunity displayed an opposing vertical pattern compared to that of the rare subcommunity,while the b-diversity for both subcommunities of prokaryotes and eukaryotes increased with water depth.Moreover,the distinct diversity patterns of abundant and rare subcommunities were associated with environmental heterogeneity and species adaptability.Notably,the b-diversity of the rare subcommunity of eukaryotes was primarily driven by species turnover in surface water,whereas nestedness became the dominant factor in deeper water.Furthermore,eukaryotic microbes exhibited a more pronounced response to changes in water depth than prokaryotes,consistent with the importance of heterogeneous selection to the eukaryotic community.Water temperature significantly affected the community composition of all groups,highlighting its importance in shaping community dynamics.This study provides valuable insights into the vertical distribution and assembly mechanisms of microbial communities in urban reservoirs,contributing to the protection and management of aquatic ecosystems under river regulation.展开更多
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.
基金supported by the National Outstanding Youth Science Fund Project of the National Natural Science Foundation of China(Grant No.51922065)the National Natural Science Foundation of China(Grant No.52179070)the Open Research Fund of Hubei International Science and Technology Cooperation Base of Fish Passage(Grant No.HIBF2020007).
文摘To restore dam-blocked natural fish migratory passages,a growing number of artificial fishways have been built in water conservancy and hydropower projects in China.The Angu hydropower station involved diverse important fish habitats in the lower reaches of the Daduhe River in Southwest China.Therefore,a vertical slot fishway(VSF)and a nature-like fishway(NLF)were built near the backwater area of the reservoir to connect the upstream and downstream habitats.Hydrodynamic and aquatic ecological surveys were conducted after the completion of the project to estimate the fish passing effect of the two fishways.The results indicated that both fishways were in effective operation and could maintain the desired hydrodynamic conditions and be used by several local fish species.During the survey,149 fish from 15 species and 111 fish from 17 species were captured by the traps in the VSF and NLF,respectively,while 1263 fish from 27 species were found in the downstream area.Some species captured in the VSF were not found in the NLF,and vice versa,which implied the different preferences of fish.Meanwhile,3789 signals including 2099 upward ones and 1690 downward ones were monitored with an ultrasonic fish detector at the inlet of the VSF.These findings revealed the characteristics of fish species observed in and near the fishways and provided valuable insights into the different fish passing capabilities of VSFandNLF.
文摘To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid dynamics(CFD)analysis.First,a CFD analysis of a two-bladed VAWT equipped with a NACA 0012 airfoil is conducted.The thrust and power coefficients are validated through experiments.Second,the blade force and velocity data at monitoring points are collected.The AOA at different azimuth angles is determined by removing the blade self-induction at the monitoring point.Then,the lift and drag coefficients as a function of AOA are extracted.Results show that this method is independent of the monitoring points selection located at certain distance to the blades and the extracted dynamic stall hysteresis is more precise than the one with the“usual”method without considering the self-induction from bound vortices.
基金supported by the National Natural Science Foundation of China(42304018)the National Natural Science Foundation of China(42330105,42064002,42074035)+3 种基金the Guangxi Natural Science Foundation of China(Guike AD23026177,2020GXNSFBA297145)the Foundation of Guilin University of Technology(GUTQDJJ6616032)Guangxi Key Laboratory of Spatial Information and Geomatics(21238-21-05)the Innovation Project of Guangxi Graduate Education(YCSW2023341)。
文摘The Zenith Hydrostatic Delay(ZHD)is essential for high-precision Global Navigation Satellite System(GNSS)and Very Long Baseline Interferometry(VLBI)data processing.Accurate estimation of ZHD relies on in situ atmospheric pressure,which is primarily variable in the vertical direction.Current atmospheric pressure is either site-specific or has limited spatial coverage,necessitating vertical corrections for broader applicability.This study introduces a model that uses a Gaussian function for the vertical correction of atmospheric pressure when in situ meteorological observations are unavailable.Validation with the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis(ERA5)reveals an average Bias and RMS for the new model of 0.31 h Pa and 2.96 h Pa,respectively.This corresponds to improvements of 37.5%and 80.3%in terms of RMS compared to two commonly used models(T0and Tvmodels)that require in situ meteorological observations,respectively.Additional validation with radiosonde data shows an average Bias and RMS of 1.85 h Pa and 4.87 h Pa,corresponding to the improvement of 42.8%and 71.1%in RMS compared with T0and Tv models,respectively.These accuracies are sufficient for calculating ZHD to an accuracy of 1 mm by performing atmospheric pressure vertical correction.The new model can correct atmospheric pressure from meteorological stations or numerical weather forecasts to different heights of the troposphere.
基金supported by the National Key Research and Development Program of China(No.2022YFB3604500,No.2022YFB3604501)the National Natural Science Foundation of China(No.52172141)the Technology Development Project of Shanxi-Zheda Institude of Advanced Materials and Chemical Engineering(No.2022SX-TD017).
文摘van der Waals(vdW)heterostructures constructed by lowdimensional(0D,1D,and 2D)materials are emerging as one of the most appealing systems in next-generation flexible photodetection.Currently,hand-stacked vdW-type photodetectors are not compatible with large-areaarray fabrication and show unimpressive performance in self-powered mode.Herein,vertical 1D GaN nanorods arrays(NRAs)/2D MoS_(2)/PEDOT:PSS in wafer scale have been proposed for self-powered flexible photodetectors arrays firstly.The as-integrated device without external bias under weak UV illumination exhibits a competitive responsivity of 1.47 A W^(−1)and a high detectivity of 1.2×10^(11)Jones,as well as a fast response speed of 54/71μs,thanks to the strong light absorption of GaN NRAs and the efficient photogenerated carrier separation in type-II heterojunction.Notably,the strain-tunable photodetection performances of device have been demonstrated.Impressively,the device at−0.78%strain and zero bias reveals a significantly enhanced photoresponse with a responsivity of 2.47 A W^(−1),a detectivity of 2.6×10^(11)Jones,and response times of 40/45μs,which are superior to the state-of-the-art self-powered flexible photodetectors.This work presents a valuable avenue to prepare tunable vdWs heterostructures for self-powered flexible photodetection,which performs well in flexible sensors.
基金supported by the National Key R&D Program of China (Grant No.2022YFF0503700)the special funds of Hubei Luojia Laboratory (Grant No.220100011)+1 种基金supported by the International Space Science Institute–Beijing(ISSI-BJ) project“The Electromagnetic Data Validation and Scientific Application Research based on CSES Satellite”and ISSI/ISSI-BJ project,“Multi-Scale Magnetosphere–Ionosphere–Thermosphere Interaction.”
文摘The Michelson Interferometer for Global High-resolution Thermospheric Imaging(MIGHTI)onboard the Ionospheric Connection Explorer(ICON)satellite offers the opportunity to investigate the altitude profile of thermospheric winds.In this study,we used the red-line measurements of MIGHTI to compare with the results estimated by Horizontal Wind Model 14(HWM14).The data selected included both the geomagnetic quiet period(December 2019 to August 2022)and the geomagnetic storm on August 26-28,2021.During the geomagnetic quiet period,the estimations of neutral winds from HWM14 showed relatively good agreement with the observations from ICON.According to the ICON observations,near the equator,zonal winds reverse from westward to eastward at around 06:00 local time(LT)at higher altitudes,and the stronger westward winds appear at later LTs at lower altitudes.At around 16:00 LT,eastward winds at 300 km reverse to westward,and vertical gradients of zonal winds similar to those at sunrise hours can be observed.In the middle latitudes,zonal winds reverse about 2-4 h earlier.Meridional winds vary more significantly than zonal winds with seasonal and latitudinal variations.According to the ICON observations,in the northern low latitudes,vertical reversals of meridional winds are found at 08:00-13:00 LT from 300 to 160 km and at around 18:00 LT from 300 to 200 km during the June solstice.Similar reversals of meridional winds are found at 04:00-07:00 LT from 300 to 160 km and at 22:00-02:00 LT from 270 to 200 km during the December solstice.In the southern low latitudes,meridional wind reversals occur at 08:00-11:00 LT from 200 to 160 km and at 21:00-02:00 LT from 300 to 200 km during the June solstice.During the December solstice,reversals of the meridional wind appear at 20:00-01:00 LT below 200 km and at 06:00-11:00 LT from 300 to 160 km.In the northern middle latitudes,the northward winds are dominant at 08:00-14:00 LT at 230 km during the June solstice.Northward winds persist until 16:00 LT at 160 and 300 km.During the December solstice,the northward winds are dominant from 06:00 to 21:00 LT.The vertical variations in neutral winds during the geomagnetic storm on August 26-28 were analyzed in detail.Both meridional and zonal winds during the active geomagnetic period observed by ICON show distinguishable vertical shear structures at different stages of the storm.On the dayside,during the main phase,the peak velocities of westward winds extend from a higher altitude to a lower altitude,whereas during the recovery phase,the peak velocities of the westward winds extend from lower altitudes to higher altitudes.The velocities of the southward winds are stronger at lower altitudes during the storm.These vertical structures of horizontal winds during the storm could not be reproduced by the HWM14 wind estimations,and the overall response to the storm of the horizontal winds in the low and middle latitudes is underestimated by HWM14.The ICON observations provide a good dataset for improving the HWM wind estimations in the middle and upper atmosphere,especially the vertical variations.
文摘This article presents four techniques for assessing verticality:the plumb line approach,the total station distance technique,the three-point centering method,and the centroid method.Given the significant error associated with the total station horizontal distance technique when measuring circular piers,this paper proposes the centroid method.This method calculates verticality by determining the coordinates of the center points at both ends of the pier.Experimental findings indicate that the centroid method achieves accuracy in measuring the verticality of circular piers comparable to the three-point centering method,while offering a faster inspection process.Furthermore,the paper explores the concept of composite verticality and validates the effectiveness of the centroid method in measuring composite verticality and its practical applications through comparative experiments.
基金Supported by the National Key Research and Development Program(2023YFC3107602)。
文摘Airborne area-array whisk-broom imaging systems typically adopt constant-speed scanning schemes.For large-inertia scanning systems,constant-speed scanning requires substantial time to complete the reversal motion,reducing the system's adaptability to high-speed reversal scanning and decreasing scanning efficiency.This study proposes a novel sinusoidal variable-speed roll scanning strategy,which reduces abrupt changes in speed and acceleration,minimizing time loss during reversals.Based on the forward image motion compensation strategy in the pitch direction,we establish a line-of-sight(LOS)position calculation model with vertical flight path correction(VFPC),ensuring that the central LOS of the scanned image remains stable on the same horizontal line,facilitating accurate image stitching in whisk-broom imaging.Through theoretical analysis and simulation experiments,the proposed method improves the scanning efficiency by approximately 18.6%at a 90o whiskbroom imaging angle under the same speed height ratio conditions.The new VFPC method enables wide-field,high-resolution imaging,achieving single-line LOS horizontal stability with an accuracy of better than O.4 mrad.The research is of great significance to promote the further development of airborne area-array whisk-broom imaging technology toward wider fields of view,higher speed height ratios,and greater scanning efficiency.
基金Supported by the Southern Marine Science and Engineering Guangdong Laboratory、Zhanjiang(No.ZJW-2019-08)APN、CRRP2019-09MYOnodera、Shinichi Onodera、and the SCS Scholar Grant(No.002029002008/2019)。
文摘Plastic pollution and microplastics in sediments are a growing concern for marine ecosystems worldwide.We examined the vertical distribution and properties of microplastics in beach sediments of Xuwen Coral Reef National Nature Reserve,in Leizhou Peninsula,Zhanjiang,China.Sediment samples were taken in seven locations at 5-cm intervals from the surface to a depth of 30 cm.The vertical distribution of microplastic particles ranged from 0 to 1340 particles per kg on average of 119.05particles per kg.The most prevalent material was fibers(76%),followed by film(12%),fragments(11.2%),and foam(0.8%).The microplastics in size of 1-2 mm constituted the largest percentage(40%)of the total,followed by those in size of<1 mm(26.4%),2-3 mm(21.2%),3-4 mm(9.6%),and 4-5 mm(2.81%).Site S1 observed maximum sizes between 1 and 2 mm,S2 reported higher availability of microplastics with sizes ranging from 0.3 to 1 mm.Six different types of polymers were identified in the investigation,and mostly were polyethylene(PE)and polypropylene(PP).In general,the observation of microplastics in deeper sediments indicates that they have the ability to last for prolonged periods in the marine environment,which may present long-term hazards to benthic creatures.In conclusion,the discovery of microplastics in deep layers of coastal sediments highlights the necessity of minimizing plastic waste and enhancing management strategies to safeguard marine environments.
基金supported by the National Natural Science Foundation of China(Grant Nos.42120104001,42192563 and 42005010)the Shanghai Sailing Program(Grant No.23YF1401400).
文摘Using observations and models from phase 6 of the Coupled Model Intercomparison Project(CMIP6),this study analyzes the performance of CMIP6 models in simulating the vertical structure of the Quasi-Biennial Oscillation(QBO)and its impacts on eastern China surface air temperature(SAT),with empirical orthogonal function(EOF)analysis.The first leading mode(EOF1)of the QBO leads to an overall cooling/warming over eastern China via the QBO’s subtropical path and Holton-Tan effect,while the second leading mode(EOF2)of the QBO tends to cause an east-west dipole of SAT anomalies between eastern and western China due to a strong Holton-Tan effect.Most models with a self-generated QBO can capture both westerly and easterly QBO anomalies in the mid-lower stratosphere in EOF1 and only westerly anomalies in EOF2.The multi-model ensemble mean can reproduce the eastern China SAT anomalies that are statistically significant and related to EOF1-like QBO events.However,the intensity of these anomalies is relatively weaker,attributable to the weak Pacific response to the subtropical effect of the QBO.In contrast,most models fail to induce a strong Holton-Tan effect and a Northern Annular Mode pattern in the polar region during the EOF2-like QBO events,resulting in weak and insignificant eastern China SAT anomalies on average.Overall,the models with a better representation of polar and Pacific responses to the QBO’s vertical structure exhibit a more reasonable eastern China SAT response,although such a response is weaker than observed.
文摘In this study,the power generation difference between the east-west and the north-south orientation of the vertically installed heterojunction solar cell(HJT)modules was deeply discussed.East-west oriented HJT module has 30%higher power generation,especially in desert photovoltaic(PV)with a bimodal distribution.While the south-north one has a single peak,the same as normal PV modules.Vertical power generation technology of HJT also has less land occupation,which is of great significance for optimizing the design of photovoltaic systems.
基金supported by the National Key R&D Program(Nos.2023YFE0108500 and 2023YFF0719500)the National Natural Science Foundation of China(Nos.52072300 and 52302199)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110538)Key Research and Development Program of Shaanxi(No.2023-GHZD-48)the Fundamental Research Funds for the Central Universities.
文摘Cadmium telluride(CdTe),which has a high average atomic number and a unique band structure,is a leading material for room-temperature X/γ-ray detectors.Resistivity and mobility are the two most important properties of detector-grade CdTe single crystals.However,despite decades of research,the fabrication of high-resistivity and high-mobility CdTe single crystals faces persistent challenges,primarily because the stoichiometric composition cannot be well controlled owing to the high volatility of Cd under high-temperature conditions.This volatility introduces Te inclusions and cadmium vacancies(V_(Cd))into the as-grown CdTe ingot,which significantly degrades the device performance.In this study,we successfully obtained detector-grade CdTe single crystals by simultaneously employing a Cd reservoir and chlorine(Cl)dopants via a vertical gradient freeze(VGF)method.By installing a Cd reservoir,we can maintain the Cd pressure under the crystal growth conditions,thereby preventing the accumulation of Te in the CdTe ingot.Additionally,the existence of the Cl dopant helps improve the CdTe resistivity by minimizing V_(Cd)density through the formation of an acceptor complex(Cl_(Te)-V_(Cd))^(-1).The crystalline quality of the obtained CdTe(Cl)was evidenced by a reduction in large Te inclusions,high optical transmission(60%),and a sharp absorption edge(1.456 eV).The presence of substitutional Cl dopants,known as Cl_(Te)^(+),simultaneously supports the record high resistivity of 1.5×10^(10)Ω·cm and remarkable electron mobility of 1075±88 cm^(2)V^(-1)s^(-1)simultaneously,has been confirmed by photoluminescence spectroscopy.Moreover,using our crystals,we fabricated a planar detector withμτ_(e)of(1.11±0.04)×10^(-4)cm^(2)∕V,which performed with a decent radiation-detection feature.This study demonstrates that the vapor-pressure-controlled VGF method is a viable technical route for fabricating detector-grade CdTe crystals.
基金supported by the National Natural Science Foundation of China (Grant No.52274035)。
文摘Ball-sealer plugging is a cost-effective method for hydraulic fracturing in vertical wells,yet the transport and plugging behavior of ball sealers remains poorly understood.This paper investigates ball-sealer plugging using both experimental and numerical approaches.A coupled computational fluid dynamics(CFD) and discrete element method(DEM) model simulates ball transport under field conditions,validated by experiments in inclined pipes.Results show that plugging performance improves with a higher flow rate ratio of the perforation,allowing effective plugging even when the ball is far from the target perforation.There exists a threshold distance between the ball and the perforation under specific conditions.The closer the ball is to the wellbore wall,the higher the likelihood of successful plugging.Low-density balls can enhance plugging performance to some extent.At high flow rates,ball inertia along the wellbore axis increases,reducing the ball's ability to redirect and weakening plugging performance.Ball interactions also affect their positioning and plugging success.In vertical wells with multiple clusters,prioritizing higher flow rates to the first fracturing cluster optimizes overall plugging performance and minimizes excessive plugging in lower,under-stimulated clusters.These findings offer valuable insights for optimizing ball-sealer deployment in well completions,improving operational outcomes.
文摘As complex and diverse ecosystems,cities encounter numerous challenges posed by both nature and humanity.Architecture,serving as the framework and texture of the city,has undoubtedly emerged as a crucial guide in addressing urban resilience issues.Roof greening and vertical greening of buildings,as ecofriendly urban green infrastructures,hold significant potential for mitigating these challenges.This paper explores the methods and strategies for implementing roof greening and vertical greening as solutions to enhance urban resilience.The objective is to offer valuable insights for sustainable urban development,encourage the widespread adoption of these greening techniques in urban construction,and ultimately strengthen urban resilience.
文摘Objectives:Sea sickness, a form of motion sickness, is a common condition among sailors on various sailing vessels, primarily due to their roll and pitch movements. While the exact neurobiological mechanisms remain unclear, the most widely accepted explanation is the sensory conflict theory,which identifies two main sources of conflict: discrepancies between visual and vestibular inputs and conflicts within the vestibular system itself.This study aims to evaluate otolith-mediated verticality perception in first-time seafarers on board a naval frigate ship using the Subjective Visual Vertical(SVV) test.Methods:This observational study was conducted on board a naval frigate and involved two groups. The case group consisted of50 newly recruited sailors experiencing their first sea voyage. The SVV test was conducted at three time points: prior to embarkation, during an active episode of sea sickness, and after disembarkation. A control group of 50 healthy, experienced sailors-regular seafarers with no history of vestibular symptoms underwent the same SVV testing at corresponding intervals. The results from both groups were collected and analyzed to assess changes in verticality perception related to sea exposure and sea sickness.Results:Analysis of the SVV test data from the 50 newly recruited sailors(case group) demonstrated a statistically significant difference compared to the control group of experienced sailors. During an active episode of sea sickness, the case group exhibited a notable tilt and deviation in SVV angles, indicating altered verticality perception. These deviations reduced significantly 24 hours post-disembarkation, suggesting an improvement in verticality perception once the motion stimulus was removed.Conclusion:This distinctive study assessed otolith-mediated verticality perception using the SVV test in first-time seafarers experiencing sea sickness aboard a naval frigate. Our findings emphasize the functional importance of the otolith organs in maintaining spatial orientation during maritime motion exposure. The observed SVV deviations support the subjective vertical conflict theory, highlighting the role of vestibular-visual mismatch in the development of sea sickness. However, our findings more likely reflect transient functional disturbance or overstimulation rather than a pre-existing utricular asymmetry alone. Based on the pattern of SVV deviation and recovery, we propose that the utricle may play a more significant role than the saccule in inducing sea sickness.
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financially supported by the National Natural Science Foundation of China (Grant No. 52371277)the State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation (Tianjin University)(Grant No. HESS-2323)+2 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province (Grant No. KYCX24_4071)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2023A1515010890)the Open foundation of Key Laboratory of Port.Waterway&Sedimentation Engineering (Grant No. Yk224001-1)。
文摘This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-source software Open FOAM~?, a two-dimensional viscous-flow numerical wave flume was developed to simulate the fluid resonant motions induced by transient focused wave groups with different spectral peak periods and wave amplitudes. The results indicate that for all the incident focused wave amplitudes considered, the amplitudes of the free surface elevation in the gap, horizontal wave force and moment all exhibit a bimodal variation trend with increasing spectral peak period. The peak values of the above amplitude-period curve appear near the resonant period of the first and second harmonic components of the free surface elevation. However, the variation in the vertical wave force versus the spectral peak period presents different patterns. In addition, the first-to fourth-order harmonic components in the wave surface and forces are further examined via the four-phase combination method. The results show that the first-to secondorder harmonic components play a dominant role in the overall amplitude.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52074315 and 52122401)Moreover,the authors also thank the financial support from China Scholarship Council(Grant No.202306440033).
文摘The diversity of interlayers in shale oil reservoir leads to a low degree of vertical reconstruction.This paper aims to propose a method to guide the synchronous initiation of hydraulic fractures in different layers by drilling multi-layer radial wells in spatial positions,and to form a fracture network that satisfies the vertical propagation range and complexity.In this paper,a 3D(three-dimensional)multi-layer radial well fracturing model considering fluid-mechanics coupling is established and the properties of shale oil reservoir are characterized according to the field geological profile.The influences of radial well spacing,fracturing fluid injection rate,and fracturing fluid viscosity on vertical fracture communication in multilayer radial wells are investigated.The results show that the radial well has the characteristics of guiding fracture penetrating interlayers.Reducing radial well spacing and appropriately increasing injection rate and viscosity are beneficial to improving vertical fracture propagation ability.However,high fracture fluid viscosity under the same displacement will lead to a significant increase in fracture aperture and weaken the total fracture area.In addition,if the stress interference around the radial wells is low,the radial well can be located in the middle of each layer to minimize the fracture height limitation.This study can provide a solution idea for vertical propagation limitation of hydraulic fractures in shale oil reservoir.
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 Key Program of the National Natural Science Foundation of China(Grant No.92047201)the Fundamental Research Funds for the Central Universities(Grant No.B230201026)+1 种基金the National Natural Science Foundation of China(Grants No.42377054 and 42007149)the Open Project of Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake(Grant No.HZHLAB2301).
文摘Reservoirs play a critical role in addressing water resources challenges.However,their vertical influence on the assembly mechanisms of different microbial communities,including prokaryotes and eukaryotes,remains unclear.This study examined the vertical diversity patterns of abundant and rare subcommunities of prokaryotes and eukaryotes in an urban reservoir,using water depth as a geographical gradient and employing high-throughput sequencing.The impact of vertical environmental heterogeneity on community structure was quantified,and key drivers of these dynamics were identified.The results indicated that the urban reservoir exhibited statistically significant differences in the vertical distribution of water temperature and oxidation/reduction potential.The a-diversity of the abundant subcommunity displayed an opposing vertical pattern compared to that of the rare subcommunity,while the b-diversity for both subcommunities of prokaryotes and eukaryotes increased with water depth.Moreover,the distinct diversity patterns of abundant and rare subcommunities were associated with environmental heterogeneity and species adaptability.Notably,the b-diversity of the rare subcommunity of eukaryotes was primarily driven by species turnover in surface water,whereas nestedness became the dominant factor in deeper water.Furthermore,eukaryotic microbes exhibited a more pronounced response to changes in water depth than prokaryotes,consistent with the importance of heterogeneous selection to the eukaryotic community.Water temperature significantly affected the community composition of all groups,highlighting its importance in shaping community dynamics.This study provides valuable insights into the vertical distribution and assembly mechanisms of microbial communities in urban reservoirs,contributing to the protection and management of aquatic ecosystems under river regulation.
