In order to satisfy a satellite horizontality requirement in an experiment, it is indispensable to monitor and adjust the horizontality of a large platform loading the satellite under the condition of ultra-low temper...In order to satisfy a satellite horizontality requirement in an experiment, it is indispensable to monitor and adjust the horizontality of a large platform loading the satellite under the condition of ultra-low temperature with real time. So the control system design and control strategy are described in detail to accomplish the horizontality monitoring and adjusting. The system adopts the industry control computer as the upper computer and the SIEMENS S7-300 PLC as the lower computer. The upper computer that bases on industry configuration software IFIX takes charge of monitoring the platform and puts forward the control strategy. PLC takes charge of receiving the adjusting instructions and controlling the legs moving to accomplish the horizontality adjusting. The horizontality adjusting strategy is emphasized and the concept of grads is introduced to establish a mathematics model of the platform inclined state, so the adjusting method is obtained. Accordingly the key question of the automatic horizontality adjusting is solved in this control system.展开更多
A horizontality adjusting system of the earth drill's platform is designed todeal with the operation difficulty of the platform which appeared while the earth drill is used.The proportional-impulse control to elim...A horizontality adjusting system of the earth drill's platform is designed todeal with the operation difficulty of the platform which appeared while the earth drill is used.The proportional-impulse control to eliminate the over-adjustment andelectricity-hydraulic-proportional control to drive the adjusting mechanism are adopted in thesystem. The control scheme and control algorithm are introduced in detail. The software flow chartis given.展开更多
Objective Poxviruses are zoonotic pathogens that infect humans,mammals,vertebrates,and arthropods.However,the specific role of ticks in transmission and evolution of these viruses remains unclear.Methods Transcriptomi...Objective Poxviruses are zoonotic pathogens that infect humans,mammals,vertebrates,and arthropods.However,the specific role of ticks in transmission and evolution of these viruses remains unclear.Methods Transcriptomic and metatranscriptomic raw data from 329 sampling pools of seven tick species across five continents were mined to assess the diversity and abundance of poxviruses.Chordopoxviral sequences were assembled and subjected to phylogenetic analysis to trace the origins of the unblasted fragments within these sequences.Results Fifty-eight poxvirus species,representing two subfamilies and 20 genera,were identified,with 212 poxviral sequences assembled.A substantial proportion of AT-rich fragments were detected in the assembled poxviral genomes.These genomic sequences contained fragments originating from rodents,archaea,and arthropods.Conclusion Our findings indicate that ticks play a significant role in the transmission and evolution of poxviruses.These viruses demonstrate the capacity to modulate virulence and adaptability through horizontal gene transfer,gene recombination,and gene mutations,thereby promoting co-existence and co-evolution with their hosts.This study advances understanding of the ecological dynamics of poxvirus transmission and evolution and highlights the potential role of ticks as vectors and vessels in these processes.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
Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stre...Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stress,the three-dimensional(3D)stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted,a newly defined characteristic parameter C_(ERP)was proposed as an indicator for evaluating the structural properties of rock masses,and a fuzzy relation matrix was established using the information distribution method.The results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with depth.There is no remarkable correlation between the elastic modulus,Poisson's ratio and depth,and the distribution of data points is scattered and messy.Moreover,there is no obvious relationship between the rock quality designation(RQD)and depth.The maximum horizontal stress σ_(H) is a function of rock properties,showing a certain linear relationship with the C_(ERP)at the same depth.In addition,the overall change trend of σ_(H) determined by the established fuzzy identification method is to increase with the increase of C_(ERP).The fuzzy identification method also demonstrates a relatively detailed local relationship betweenσ_H and C_(ERP),and the predicted curve rises in a fluctuating way,which is in accord well with the measured stress data.展开更多
Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives ...Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives and may lead them to be confined to bed.However,the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is unclear.To address this issue,we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022.A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral sclerosis.We used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis patients.Multiple factor analyses revealed that higher upper motor neuron scores(hazard ratio[HR]=1.05,95%confidence interval[CI]=1.01–1.09,P=0.018),onset in the left limb(HR=0.72,95%CI=0.58–0.89,P=0.002),and a horizontal pattern of progression(HR=0.46,95%CI=0.37–0.58,P<0.001)were risk factors for a shorter interval until bilateral limb involvement.The results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis patients.These findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis.展开更多
Predicting the productivity of multistage fractured horizontal wells plays an important role in exploiting unconventional resources.In recent years,machine learning(ML)models have emerged as a new approach for such st...Predicting the productivity of multistage fractured horizontal wells plays an important role in exploiting unconventional resources.In recent years,machine learning(ML)models have emerged as a new approach for such studies.However,the scarcity of sufficient real data for model training often leads to imprecise predictions,even though the models trained with real data better characterize geological and engineering features.To tackle this issue,we propose an ML model that can obtain reliable results even with a small amount of data samples.Our model integrates the synthetic minority oversampling technique(SMOTE)to expand the data volume,the support vector machine(SVM)for model training,and the particle swarm optimization(PSO)algorithm for optimizing hyperparameters.To enhance the model performance,we conduct feature fusion and dimensionality reduction.Additionally,we examine the influences of different sample sizes and ML models for training.The proposed model demonstrates higher prediction accuracy and generalization ability,achieving a predicted R^(2)value of up to 0.9 for the test set,compared to the traditional ML techniques with an R^(2)of 0.13.This model accurately predicts the production of fractured horizontal wells even with limited samples,supplying an efficient tool for optimizing the production of unconventional resources.Importantly,the model holds the potential applicability to address similar challenges in other fields constrained by scarce data samples.展开更多
The escalating global dissemination of plasmid-mediated antibiotic resistance poses a formidable threat to global health.Conjugation stands as a pivotal mechanism for horizontal gene transfer among bacterial populatio...The escalating global dissemination of plasmid-mediated antibiotic resistance poses a formidable threat to global health.Conjugation stands as a pivotal mechanism for horizontal gene transfer among bacterial populations,facilitating the spread of antibiotic resistance genes(ARGs).Microelectrolysis has garnered attention as an efficacious strategy for mitigating antibiotic concentrations in wastewater,yet its potential impact on ARG horizontal transfer remain largely unexplored.This comprehensive investigation unveils that microelectrolysis not only influences but significantly accelerates the conjugative transfer of ARG-harboring plasmids.Remarkably,this phenomenon is corroborated at the microbial community scale,underscoring its ecological relevance.Alarmingly,the study highlights the vulnerability of intestinalmicroorganisms to acquire antibiotic resistance under electrolytic stimulation,posing heightened risks to both animal and human health.Delving deeper,the study elucidates the underlyingmechanisms responsible for this enhanced conjugative transfer.It reveals that microelectrolysis augments the abundance of mating-competent cells,triggers the generation of reactive oxygen species,inflicts modest membrane damage,and upregulates the expression of genes critical for conjugation.These findings collectively contribute to a more profound comprehension of the environmental dissemination dynamics and associated public health implications of ARGs in the context of wastewater treatment employing microelectrolytic technologies.展开更多
Inflammatory bowel disease(IBD),encompassing Crohn's disease and ulcerative colitis,is a chronic condition marked by recurring gastrointestinal inflammation.While immune,genetic,and environmental factors are well-...Inflammatory bowel disease(IBD),encompassing Crohn's disease and ulcerative colitis,is a chronic condition marked by recurring gastrointestinal inflammation.While immune,genetic,and environmental factors are well-studied,the gut virome has received less attention.This editorial highlights the work which investigates the gut virome’s role in IBD and its interactions with the bacterial microbiome and host immune system.The gut virome consists of bacteriophages,eukaryotic viruses,and endogenous retroviruses.Among these,Caudovirales bacteriophages are predominant and influence bacterial communities via lysogenic and lytic cycles.Eukaryotic viruses infect host cells directly,while endogenous retroviruses impact gene regulation and immune responses.In IBD,the virome shows distinct alterations,including an increased abundance of Caudovirales phages and reduced Microviridae diversity,suggesting a pro-inflammatory viral environment.Dysbiosis,chronic inflammation,and aberrant immune responses contribute to these changes by disrupting microbial communities and modifying virome composition.Phages affect bacterial dynamics through lysis,lysogeny,and horizontal gene transfer,shaping microbial adaptability and resilience.Understanding these interactions is crucial for identifying novel therapeutic targets and restoring microbial balance in IBD.展开更多
The China Spallation Neutron Source(CSNS)is the fourth pulsed accelerator-driven neutron source in the world,and it achieved its design target of 100 kW in 2020.The planned China Spallation Neutron Source Phase II(CSN...The China Spallation Neutron Source(CSNS)is the fourth pulsed accelerator-driven neutron source in the world,and it achieved its design target of 100 kW in 2020.The planned China Spallation Neutron Source Phase II(CSNS-II)commenced in 2024.The CSNS-II linac design primarily involves the addition of a radio-frequency ion source and a section of a superconducting linear accelerator composed of two types of superconducting cavities,namely double-spoke and six-cell elliptical cavities,after the drift tube linac(DTL).The development of the double-spoke superconducting cavity began in early 2021,and by January 2023,the welding,post-processing,and vertical tests of two 324 MHz double-spoke cavity prototypes were completed,with vertical test gradients of 11.6 and 15 MV/m,and Q_(0)≥3×10^(10)@E_(acc)≤10 MV/m.The R&D of the cryomodule began in January 2022.In October 2023,the clean assembly of the double-spoke cavity string and cold mass installation of the cryomodule commenced,with the installation of the cryomodule and valve box completing in two months.In January 2024,a horizontal test of the cryomodule was completed,making it the first double-spoke cavity cryomodule in China.The test results showed that the maximum gradients of the two superconducting cavities at a pulse width of 4 ms and repetition frequency of 25 Hz were 12.8 and 15.2 MV/m,respectively.This article provides a detailed introduction to the double-spoke superconducting cavity,tuner,coupler,and cryomodule,elaborates on the clean assembly of the cavity string and cold mass installation of the cryomodule,and provides a detailed analysis of the horizontal test results.展开更多
Time-averaged thermal convection in a rotating horizontal annulus with a higher temperature at its inner boundary is studied.The centrifugal force plays a stabilizing role,while thermal convection is determined by the...Time-averaged thermal convection in a rotating horizontal annulus with a higher temperature at its inner boundary is studied.The centrifugal force plays a stabilizing role,while thermal convection is determined by the“thermovibrational mechanism”.Convective flow is excited due to oscillations of a non-isothermal rotating fluid.Thermal vibrational convectionmanifests in the form of two-dimensional vortices elongated along the axis of rotation,which develop in a threshold manner with an increase in the amplitude of fluid oscillations.The objective of the present study is to clarify the nature of another phenomenon,i.e.,three-dimensional convective vortices observed in the experiments both before the excitation of the convection described above and in the supercritical region.The experimental study of the oscillatory and the time-averaged flow fields by particle image velocimetry is accompanied by the theoretical research of inertial waves.It is found that three-dimensional fluid flows owe their origin to inertial waves.This is confirmed by a high degree of agreement between the experimental and theoretical results.Experiments with cavities of different lengths indicate that the vortices are clearly seen in cavities thatmeet the conditions of resonant excitation of inertial modes.Furthermore,the length of the cavity has no effect on heat transfer,which is explained by the comparatively low intensity of the wave-induced flows.The main contribution to heat transfer is due to vortices elongated along the axis of rotation.The novel results are of significant practical importance in various fields.展开更多
Measurements from a hyperspectral infrared(HIR) sounder onboard a satellite in geostationary orbit not only provide atmospheric thermodynamic information,but also can be used to infer dynamic information with high tem...Measurements from a hyperspectral infrared(HIR) sounder onboard a satellite in geostationary orbit not only provide atmospheric thermodynamic information,but also can be used to infer dynamic information with high temporal resolution.Radiance measurements from the Geostationary Interferometric Infrared Sounder(GIIRS),obtained with 15-min temporal resolution during Typhoon Maria(2018) and 30-min temporal resolution during Typhoon Lekima(2019),were used to derive three-dimensional(3D) horizontal winds by tracking the motion of atmospheric moisture.This work focused on the impact of assimilation of 3D winds on typhoon analyses and forecasts using the operational NWP model of the China Meteorological Administration(CMA-MESO),and improved understanding of the potential benefits of assimilating dynamic information from geostationary sounder data with higher temporal resolution.The standard deviation of the observations minus simulations revealed that the accuracy of the derived 3D winds with 15-min resolution was higher than that of derived winds with 30-min resolution.Experiments showed that the assimilation system can effectively absorb the information of the derived 3D winds,and that dynamic information from clear-sky areas can be transferred to typhoon areas.In typhoon prediction,assimilation of the derived 3D winds had greatest influence on the typhoon track,and less influence on the maximum wind speed.Assimilation of the derived 3D winds reduced the average track error by 17.4% for Typhoon Maria(2018) and by 3.5% for Typhoon Lekima(2019) during their entire 36-h forecasts initiated at different times.Assimilation of GIIRS dynamic information can substantially improve forecasts of heavy precipitation by CMAMESO.Results indicate that the assimilation of dynamic information from high-temporal-resolution geostationary HIR sounder data adds value for improved numerical weather prediction.展开更多
The Tashkent region is one of the most tectonically and seismically active areas in Uzbekistan. Although it is highly significant, the understanding and quantification of current deformation processes are still incomp...The Tashkent region is one of the most tectonically and seismically active areas in Uzbekistan. Although it is highly significant, the understanding and quantification of current deformation processes are still incomplete, especially concerning space-based geodetic techniques like the Global Navigation Satellite System(GNSS). Using velocity field data from 16 permanent GNSS sites during 2018-2023, this paper analyzes the strain rate field and its spatial characteristics using an improved least squares collocation method. The results indicate a northeastward motion consistent with India-Eurasian convergence, with velocities ranging from 24.7 to 30.1 mm/yr and increasing from northwest to southeast. The region displays substantial positive dilation at a rate of 14.7 nanostrain/yr, while the neighboring areas demonstrate negative dilation ranging from-10 to-30 nanostrain/yr. The second strain rate invariant with an average value of 20 nanostrain/yr primarily occurs along the Karzhantau fault. The spatial features of strain rate fields delineate the extensional and compressional strain zones, bounded in the west by the Tien Shan orogenic belt. Therefore, these zones warrant increased attention due to their relatively higher seismic risk in the Tashkent region.展开更多
Solar energy is a pivotal clean energy source in the transition to carbon neutrality from fossil fuels.However,the intermittent and stochastic characteristics of solar radiation pose challenges for accurate simulation...Solar energy is a pivotal clean energy source in the transition to carbon neutrality from fossil fuels.However,the intermittent and stochastic characteristics of solar radiation pose challenges for accurate simulation and prediction.Accurately simulating and predicting solar radiation and its variability are crucial for optimizing solar energy utilization.This study conducted simulation experiments using the WRF-Solar model from 25 June to 25 July 2022,to evaluate the accuracy and performance of the simulated solar radiation across China.The simulations covered the whole country with a grid spacing of 27 km and were compared with ground observation network data from the Chinese Ecosystem Research Network.The results indicated that WRF-Solar can accurately capture the spatiotemporal patterns of global horizontal irradiance over China,but there is still an overestimation of solar radiation,and the model underestimates the total cloud cover.The root-mean-square error ranged from 92.83 to 188.13 W m^(-2) and the mean bias(MB)ranged from 21.05 to 56.22 W m^(-2).The simulation showed the smallest MB at Lhasa on the Qinghai–Tibet Plateau,while the largest MB was observed in Southeast China.To enhance the accuracy of solar radiation simulation,the authors compared the Fast All-sky Radiation Model for Solar with the Rapid Radiative Transfer Model for General Circulation Models and found that the former provides better simulation.展开更多
Microorganisms play a critical role in the biotransformation of arsenic and the form which it exists in the environment. In this study, a methyl parathion-degrading bacterium Caballeronia jiangsuensis, isolated from a...Microorganisms play a critical role in the biotransformation of arsenic and the form which it exists in the environment. In this study, a methyl parathion-degrading bacterium Caballeronia jiangsuensis, isolated from an abandoned pesticide manufacturing plant, was used to analyze arsenic accumulation and transformation. The accumulation of trivalent organoarsenic compounds in C. jiangsuensis occurred to a greater extent than that of their pentavalent counterparts. The chromosome of C. jiangsuensis contains an arsenic gene island whose GC content is significantly lower than that of the genome, suggesting that the island was acquired via horizontal gene transfer. There was approximately 90%-99% similarity between the proteins encoded by the gene island and the corresponding sequence of the plasmid pkk5 from Burkholderia sp. KK1. The biotransformation of different arsenic species by C. jiangsuensis was subsequently analyzed. The results revealed that monomethylarsenic acid(MAs(Ⅴ)) was rapidly demethylated to arsenate with very small amounts of intermediate monomethylarsonous acid(MAs(Ⅲ)), whereas MAs(Ⅲ) was largely oxidized to MAs(Ⅴ) despite the occurrence of the gene arsI probably responsible for aerobic demethylation of MAs(Ⅲ) in C. jiangsuensis. In addition, dimethylarsenic acid was partly demethylated to arsenate. Horizontal gene transfer of ars operon from a plasmid to other bacteria represents an adaptation to a specific environment. This study provides a new perspective for understanding arsenic biogeochemical cycling.展开更多
Horizontal wells play a crucial role in enhancing shale gas reservoir production.This study employs transient multiphase simulation to investigate the impact of well trajectory on production optimization throughout a ...Horizontal wells play a crucial role in enhancing shale gas reservoir production.This study employs transient multiphase simulation to investigate the impact of well trajectory on production optimization throughout a well’s life cycle.The research uses OLGATM as a simulator to examine six well trajectories:toe-up,toe-down,smooth horizontal,undulated toe-up,undulated toe-down,and undulated horizontal.Initial findings indicate comparable production rates across different trajectories during the early production phase,with toe-up wells showing slightly better performances due to minimal slugging.However,as the reservoir pressure decreases,the well trajectory significantly influences production.Horizontal wells achieve the highest accumulated gas production rates due to minimal liquid holdup and back pressure.Toe-up wells experience early liquid accumulation and severe slugging,leading to increased back pressure and smaller production.The study highlights the positive effects of lateral undulations on toe-up and toe-down wells in terms of liquid unloading,however some emphasis is also put on their adverse influence on horizontal wells.展开更多
In the 3D inversion modeling of gravity and magnetic potential field data,the model weighting function is often applied to overcome the skin eff ect of inversion results.However,divergence occurs at the the deep area,...In the 3D inversion modeling of gravity and magnetic potential field data,the model weighting function is often applied to overcome the skin eff ect of inversion results.However,divergence occurs at the the deep area,and artificial weak negative anomalies form around the positive anomalies in the horizontal direction,resulting in a reduction in the overall resolution.To fully utilize the model weighting function,this study constructs a combined model weighting function.First,a new depth weighting function is constructed by adding a regulator into the conventional depth weighting function to overcome the skin eff ect and inhibit the divergence at the deep area of the inversion results.A horizontal weighting function is then constructed by extracting information from the observation data;this function can suppress the formation of artificial weak anomalies and improve the horizontal resolution of the inversion results.Finally,these two functions are coupled to obtain the combined model weighting function,which can replace the conventional depth weighting function in 3D inversion.It improves the vertical and horizontal resolution of the inversion results without increasing the algorithm complexity and calculation amount,is easy to operate,and adapts to any 3D inversion method.Two model experiments are designed to verify the effectiveness,practicability,and anti-noise of the combined model weighting function.Then the function is applied to the 3D inversion of the measured aeromagnetic data in the Jinchuan area in China.The obtained inversion results are in good agreement with the known geological data.展开更多
As an important part of offshore wind turbine support and fixed units, the multibucket jacket foundation bears large loads and a complex marine environment. In this paper, the horizontal bearing characteristics of the...As an important part of offshore wind turbine support and fixed units, the multibucket jacket foundation bears large loads and a complex marine environment. In this paper, the horizontal bearing characteristics of the four-bucket jacket foundation of offshore wind power in sandy soil are studied. Through model tests and numerical simulations, the influence of bucket foundation sealing properties, load application speed, and loading direction on foundation-bearing capacity are discussed. The results show that the horizontal ultimate bearing capacity of the foundation in the nonsealing condition is decreased by 51.3% compared with the sealing condition;therefore, after the foundation penetration construction is completed, the bucket sealing must be ensured to increase the load-bearing performance of the structure. At a loading speed of 3.25 mm/s, the horizontal ultimate bearing capacity of the foundation is increased by 9.4% over the working condition of 1.85 mm/s. The bearing capacity of the foundation is maximized in the loading direction α =45° and is the smallest when α =0°. That is, the foundation can maximize its loadbearing performance under the condition of single-bucket compression/tension. During the design process, the main load of the structure should be loaded in the 45° direction. The contrast error of the experiment and numerical simulation does not exceed 10%. The research results have important guiding importance for designing and constructing the jacket foundation and can be used as a reference for the stable operation and sustainable development of offshore wind power systems.展开更多
HighlightsA novel conjugative plasmid pHJ90-cfr carrying the multiresistance gene cfr was characterized in Proteus vulgaris.A new IS5-family member,ISPmi4,was identified for the first time.Both plasmids and ICEs were ...HighlightsA novel conjugative plasmid pHJ90-cfr carrying the multiresistance gene cfr was characterized in Proteus vulgaris.A new IS5-family member,ISPmi4,was identified for the first time.Both plasmids and ICEs were vital mobile genetic elements for horizontal transmission of cfr gene in Proteus species.展开更多
文摘In order to satisfy a satellite horizontality requirement in an experiment, it is indispensable to monitor and adjust the horizontality of a large platform loading the satellite under the condition of ultra-low temperature with real time. So the control system design and control strategy are described in detail to accomplish the horizontality monitoring and adjusting. The system adopts the industry control computer as the upper computer and the SIEMENS S7-300 PLC as the lower computer. The upper computer that bases on industry configuration software IFIX takes charge of monitoring the platform and puts forward the control strategy. PLC takes charge of receiving the adjusting instructions and controlling the legs moving to accomplish the horizontality adjusting. The horizontality adjusting strategy is emphasized and the concept of grads is introduced to establish a mathematics model of the platform inclined state, so the adjusting method is obtained. Accordingly the key question of the automatic horizontality adjusting is solved in this control system.
文摘A horizontality adjusting system of the earth drill's platform is designed todeal with the operation difficulty of the platform which appeared while the earth drill is used.The proportional-impulse control to eliminate the over-adjustment andelectricity-hydraulic-proportional control to drive the adjusting mechanism are adopted in thesystem. The control scheme and control algorithm are introduced in detail. The software flow chartis given.
基金financially supported by the Shanghai New Three-Year Action Plan for Public Health(Grant No.GWVI-11.1-03)National Natural Science Foundation of China(Grant No.81872673).
文摘Objective Poxviruses are zoonotic pathogens that infect humans,mammals,vertebrates,and arthropods.However,the specific role of ticks in transmission and evolution of these viruses remains unclear.Methods Transcriptomic and metatranscriptomic raw data from 329 sampling pools of seven tick species across five continents were mined to assess the diversity and abundance of poxviruses.Chordopoxviral sequences were assembled and subjected to phylogenetic analysis to trace the origins of the unblasted fragments within these sequences.Results Fifty-eight poxvirus species,representing two subfamilies and 20 genera,were identified,with 212 poxviral sequences assembled.A substantial proportion of AT-rich fragments were detected in the assembled poxviral genomes.These genomic sequences contained fragments originating from rodents,archaea,and arthropods.Conclusion Our findings indicate that ticks play a significant role in the transmission and evolution of poxviruses.These viruses demonstrate the capacity to modulate virulence and adaptability through horizontal gene transfer,gene recombination,and gene mutations,thereby promoting co-existence and co-evolution with their hosts.This study advances understanding of the ecological dynamics of poxvirus transmission and evolution and highlights the potential role of ticks as vectors and vessels in these processes.
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.
基金financially supported by the National Natural Science Foundation of China(No.52204084)the Open Research Fund of the State Key Laboratory of Coal Resources and safe Mining,CUMT,China(No.SKLCRSM 23KF004)+3 种基金the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities),China(No.FRF-IDRY-GD22-002)the Fundamental Research Funds for the Central Universities and the Youth Teacher International Exchange and Growth Program,China(No.QNXM20220009)the National Key R&D Program of China(Nos.2022YFC2905600 and 2022 YFC3004601)the Science,Technology&Innovation Project of Xiongan New Area,China(No.2023XAGG0061)。
文摘Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stress,the three-dimensional(3D)stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted,a newly defined characteristic parameter C_(ERP)was proposed as an indicator for evaluating the structural properties of rock masses,and a fuzzy relation matrix was established using the information distribution method.The results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with depth.There is no remarkable correlation between the elastic modulus,Poisson's ratio and depth,and the distribution of data points is scattered and messy.Moreover,there is no obvious relationship between the rock quality designation(RQD)and depth.The maximum horizontal stress σ_(H) is a function of rock properties,showing a certain linear relationship with the C_(ERP)at the same depth.In addition,the overall change trend of σ_(H) determined by the established fuzzy identification method is to increase with the increase of C_(ERP).The fuzzy identification method also demonstrates a relatively detailed local relationship betweenσ_H and C_(ERP),and the predicted curve rises in a fluctuating way,which is in accord well with the measured stress data.
基金supported by the National Natural Science Foundation of China,Nos.82071426,81873784Clinical Cohort Construction Program of Peking University Third Hospital,No.BYSYDL2019002(all to DF)。
文摘Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives and may lead them to be confined to bed.However,the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is unclear.To address this issue,we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022.A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral sclerosis.We used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis patients.Multiple factor analyses revealed that higher upper motor neuron scores(hazard ratio[HR]=1.05,95%confidence interval[CI]=1.01–1.09,P=0.018),onset in the left limb(HR=0.72,95%CI=0.58–0.89,P=0.002),and a horizontal pattern of progression(HR=0.46,95%CI=0.37–0.58,P<0.001)were risk factors for a shorter interval until bilateral limb involvement.The results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis patients.These findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis.
基金supported by the National Natural Science Foundation of China(52274055)the Shandong Provincial Natural Science Foundation(ZR2022YQ50)the Taishan Scholar Program of Shandong Province(tsqn202408088)。
文摘Predicting the productivity of multistage fractured horizontal wells plays an important role in exploiting unconventional resources.In recent years,machine learning(ML)models have emerged as a new approach for such studies.However,the scarcity of sufficient real data for model training often leads to imprecise predictions,even though the models trained with real data better characterize geological and engineering features.To tackle this issue,we propose an ML model that can obtain reliable results even with a small amount of data samples.Our model integrates the synthetic minority oversampling technique(SMOTE)to expand the data volume,the support vector machine(SVM)for model training,and the particle swarm optimization(PSO)algorithm for optimizing hyperparameters.To enhance the model performance,we conduct feature fusion and dimensionality reduction.Additionally,we examine the influences of different sample sizes and ML models for training.The proposed model demonstrates higher prediction accuracy and generalization ability,achieving a predicted R^(2)value of up to 0.9 for the test set,compared to the traditional ML techniques with an R^(2)of 0.13.This model accurately predicts the production of fractured horizontal wells even with limited samples,supplying an efficient tool for optimizing the production of unconventional resources.Importantly,the model holds the potential applicability to address similar challenges in other fields constrained by scarce data samples.
基金supported by Jiangsu Agriculture Science and Technology Innovation Fund(No.CX(22)3001)。
文摘The escalating global dissemination of plasmid-mediated antibiotic resistance poses a formidable threat to global health.Conjugation stands as a pivotal mechanism for horizontal gene transfer among bacterial populations,facilitating the spread of antibiotic resistance genes(ARGs).Microelectrolysis has garnered attention as an efficacious strategy for mitigating antibiotic concentrations in wastewater,yet its potential impact on ARG horizontal transfer remain largely unexplored.This comprehensive investigation unveils that microelectrolysis not only influences but significantly accelerates the conjugative transfer of ARG-harboring plasmids.Remarkably,this phenomenon is corroborated at the microbial community scale,underscoring its ecological relevance.Alarmingly,the study highlights the vulnerability of intestinalmicroorganisms to acquire antibiotic resistance under electrolytic stimulation,posing heightened risks to both animal and human health.Delving deeper,the study elucidates the underlyingmechanisms responsible for this enhanced conjugative transfer.It reveals that microelectrolysis augments the abundance of mating-competent cells,triggers the generation of reactive oxygen species,inflicts modest membrane damage,and upregulates the expression of genes critical for conjugation.These findings collectively contribute to a more profound comprehension of the environmental dissemination dynamics and associated public health implications of ARGs in the context of wastewater treatment employing microelectrolytic technologies.
文摘Inflammatory bowel disease(IBD),encompassing Crohn's disease and ulcerative colitis,is a chronic condition marked by recurring gastrointestinal inflammation.While immune,genetic,and environmental factors are well-studied,the gut virome has received less attention.This editorial highlights the work which investigates the gut virome’s role in IBD and its interactions with the bacterial microbiome and host immune system.The gut virome consists of bacteriophages,eukaryotic viruses,and endogenous retroviruses.Among these,Caudovirales bacteriophages are predominant and influence bacterial communities via lysogenic and lytic cycles.Eukaryotic viruses infect host cells directly,while endogenous retroviruses impact gene regulation and immune responses.In IBD,the virome shows distinct alterations,including an increased abundance of Caudovirales phages and reduced Microviridae diversity,suggesting a pro-inflammatory viral environment.Dysbiosis,chronic inflammation,and aberrant immune responses contribute to these changes by disrupting microbial communities and modifying virome composition.Phages affect bacterial dynamics through lysis,lysogeny,and horizontal gene transfer,shaping microbial adaptability and resilience.Understanding these interactions is crucial for identifying novel therapeutic targets and restoring microbial balance in IBD.
文摘The China Spallation Neutron Source(CSNS)is the fourth pulsed accelerator-driven neutron source in the world,and it achieved its design target of 100 kW in 2020.The planned China Spallation Neutron Source Phase II(CSNS-II)commenced in 2024.The CSNS-II linac design primarily involves the addition of a radio-frequency ion source and a section of a superconducting linear accelerator composed of two types of superconducting cavities,namely double-spoke and six-cell elliptical cavities,after the drift tube linac(DTL).The development of the double-spoke superconducting cavity began in early 2021,and by January 2023,the welding,post-processing,and vertical tests of two 324 MHz double-spoke cavity prototypes were completed,with vertical test gradients of 11.6 and 15 MV/m,and Q_(0)≥3×10^(10)@E_(acc)≤10 MV/m.The R&D of the cryomodule began in January 2022.In October 2023,the clean assembly of the double-spoke cavity string and cold mass installation of the cryomodule commenced,with the installation of the cryomodule and valve box completing in two months.In January 2024,a horizontal test of the cryomodule was completed,making it the first double-spoke cavity cryomodule in China.The test results showed that the maximum gradients of the two superconducting cavities at a pulse width of 4 ms and repetition frequency of 25 Hz were 12.8 and 15.2 MV/m,respectively.This article provides a detailed introduction to the double-spoke superconducting cavity,tuner,coupler,and cryomodule,elaborates on the clean assembly of the cavity string and cold mass installation of the cryomodule,and provides a detailed analysis of the horizontal test results.
基金funded by the Ministry of Education of the Russian Federation within the framework of a state assignment,number 1023032300071-6-2.3.1.
文摘Time-averaged thermal convection in a rotating horizontal annulus with a higher temperature at its inner boundary is studied.The centrifugal force plays a stabilizing role,while thermal convection is determined by the“thermovibrational mechanism”.Convective flow is excited due to oscillations of a non-isothermal rotating fluid.Thermal vibrational convectionmanifests in the form of two-dimensional vortices elongated along the axis of rotation,which develop in a threshold manner with an increase in the amplitude of fluid oscillations.The objective of the present study is to clarify the nature of another phenomenon,i.e.,three-dimensional convective vortices observed in the experiments both before the excitation of the convection described above and in the supercritical region.The experimental study of the oscillatory and the time-averaged flow fields by particle image velocimetry is accompanied by the theoretical research of inertial waves.It is found that three-dimensional fluid flows owe their origin to inertial waves.This is confirmed by a high degree of agreement between the experimental and theoretical results.Experiments with cavities of different lengths indicate that the vortices are clearly seen in cavities thatmeet the conditions of resonant excitation of inertial modes.Furthermore,the length of the cavity has no effect on heat transfer,which is explained by the comparatively low intensity of the wave-induced flows.The main contribution to heat transfer is due to vortices elongated along the axis of rotation.The novel results are of significant practical importance in various fields.
基金supported by the National Natural Science Foundation of China(Grant No.U2142201)the Fengyun Application Pion eering Project(Grant No.FY-APP-ZX-2022.01)。
文摘Measurements from a hyperspectral infrared(HIR) sounder onboard a satellite in geostationary orbit not only provide atmospheric thermodynamic information,but also can be used to infer dynamic information with high temporal resolution.Radiance measurements from the Geostationary Interferometric Infrared Sounder(GIIRS),obtained with 15-min temporal resolution during Typhoon Maria(2018) and 30-min temporal resolution during Typhoon Lekima(2019),were used to derive three-dimensional(3D) horizontal winds by tracking the motion of atmospheric moisture.This work focused on the impact of assimilation of 3D winds on typhoon analyses and forecasts using the operational NWP model of the China Meteorological Administration(CMA-MESO),and improved understanding of the potential benefits of assimilating dynamic information from geostationary sounder data with higher temporal resolution.The standard deviation of the observations minus simulations revealed that the accuracy of the derived 3D winds with 15-min resolution was higher than that of derived winds with 30-min resolution.Experiments showed that the assimilation system can effectively absorb the information of the derived 3D winds,and that dynamic information from clear-sky areas can be transferred to typhoon areas.In typhoon prediction,assimilation of the derived 3D winds had greatest influence on the typhoon track,and less influence on the maximum wind speed.Assimilation of the derived 3D winds reduced the average track error by 17.4% for Typhoon Maria(2018) and by 3.5% for Typhoon Lekima(2019) during their entire 36-h forecasts initiated at different times.Assimilation of GIIRS dynamic information can substantially improve forecasts of heavy precipitation by CMAMESO.Results indicate that the assimilation of dynamic information from high-temporal-resolution geostationary HIR sounder data adds value for improved numerical weather prediction.
基金funding of the Academy of Sciences of the Republic of Uzbekistan
文摘The Tashkent region is one of the most tectonically and seismically active areas in Uzbekistan. Although it is highly significant, the understanding and quantification of current deformation processes are still incomplete, especially concerning space-based geodetic techniques like the Global Navigation Satellite System(GNSS). Using velocity field data from 16 permanent GNSS sites during 2018-2023, this paper analyzes the strain rate field and its spatial characteristics using an improved least squares collocation method. The results indicate a northeastward motion consistent with India-Eurasian convergence, with velocities ranging from 24.7 to 30.1 mm/yr and increasing from northwest to southeast. The region displays substantial positive dilation at a rate of 14.7 nanostrain/yr, while the neighboring areas demonstrate negative dilation ranging from-10 to-30 nanostrain/yr. The second strain rate invariant with an average value of 20 nanostrain/yr primarily occurs along the Karzhantau fault. The spatial features of strain rate fields delineate the extensional and compressional strain zones, bounded in the west by the Tien Shan orogenic belt. Therefore, these zones warrant increased attention due to their relatively higher seismic risk in the Tashkent region.
基金supported by the National Natural Science Foundation of China[grant number 42175132]the National Key R&D Program[grant number 2020YFA0607802]the CAS Information Technology Program[grant number CAS-WX2021SF-0107-02]。
文摘Solar energy is a pivotal clean energy source in the transition to carbon neutrality from fossil fuels.However,the intermittent and stochastic characteristics of solar radiation pose challenges for accurate simulation and prediction.Accurately simulating and predicting solar radiation and its variability are crucial for optimizing solar energy utilization.This study conducted simulation experiments using the WRF-Solar model from 25 June to 25 July 2022,to evaluate the accuracy and performance of the simulated solar radiation across China.The simulations covered the whole country with a grid spacing of 27 km and were compared with ground observation network data from the Chinese Ecosystem Research Network.The results indicated that WRF-Solar can accurately capture the spatiotemporal patterns of global horizontal irradiance over China,but there is still an overestimation of solar radiation,and the model underestimates the total cloud cover.The root-mean-square error ranged from 92.83 to 188.13 W m^(-2) and the mean bias(MB)ranged from 21.05 to 56.22 W m^(-2).The simulation showed the smallest MB at Lhasa on the Qinghai–Tibet Plateau,while the largest MB was observed in Southeast China.To enhance the accuracy of solar radiation simulation,the authors compared the Fast All-sky Radiation Model for Solar with the Rapid Radiative Transfer Model for General Circulation Models and found that the former provides better simulation.
基金supported by the National Natural Science Foundation of China(Nos.42077289,42277197,and 41877422).
文摘Microorganisms play a critical role in the biotransformation of arsenic and the form which it exists in the environment. In this study, a methyl parathion-degrading bacterium Caballeronia jiangsuensis, isolated from an abandoned pesticide manufacturing plant, was used to analyze arsenic accumulation and transformation. The accumulation of trivalent organoarsenic compounds in C. jiangsuensis occurred to a greater extent than that of their pentavalent counterparts. The chromosome of C. jiangsuensis contains an arsenic gene island whose GC content is significantly lower than that of the genome, suggesting that the island was acquired via horizontal gene transfer. There was approximately 90%-99% similarity between the proteins encoded by the gene island and the corresponding sequence of the plasmid pkk5 from Burkholderia sp. KK1. The biotransformation of different arsenic species by C. jiangsuensis was subsequently analyzed. The results revealed that monomethylarsenic acid(MAs(Ⅴ)) was rapidly demethylated to arsenate with very small amounts of intermediate monomethylarsonous acid(MAs(Ⅲ)), whereas MAs(Ⅲ) was largely oxidized to MAs(Ⅴ) despite the occurrence of the gene arsI probably responsible for aerobic demethylation of MAs(Ⅲ) in C. jiangsuensis. In addition, dimethylarsenic acid was partly demethylated to arsenate. Horizontal gene transfer of ars operon from a plasmid to other bacteria represents an adaptation to a specific environment. This study provides a new perspective for understanding arsenic biogeochemical cycling.
基金supported by a postdoctoral project from PetroChina Southwest Oil and Gas Field Company,titled“Research on Flow Behavior of Horizontal Shale Gas Wellbore Based on Reservoir-Wellbore Coupling”(Project Number:2024D103-02-08).
文摘Horizontal wells play a crucial role in enhancing shale gas reservoir production.This study employs transient multiphase simulation to investigate the impact of well trajectory on production optimization throughout a well’s life cycle.The research uses OLGATM as a simulator to examine six well trajectories:toe-up,toe-down,smooth horizontal,undulated toe-up,undulated toe-down,and undulated horizontal.Initial findings indicate comparable production rates across different trajectories during the early production phase,with toe-up wells showing slightly better performances due to minimal slugging.However,as the reservoir pressure decreases,the well trajectory significantly influences production.Horizontal wells achieve the highest accumulated gas production rates due to minimal liquid holdup and back pressure.Toe-up wells experience early liquid accumulation and severe slugging,leading to increased back pressure and smaller production.The study highlights the positive effects of lateral undulations on toe-up and toe-down wells in terms of liquid unloading,however some emphasis is also put on their adverse influence on horizontal wells.
基金jointly funded by the National Natural Science Foundation of China(No.U2244220,No.42004125)the China Geological Survey Projects(No.DD20240119,No.DD20243245,No.DD20230114,No.DD20243244)the China Postdoctoral Science Foundation(No.2020M670601)。
文摘In the 3D inversion modeling of gravity and magnetic potential field data,the model weighting function is often applied to overcome the skin eff ect of inversion results.However,divergence occurs at the the deep area,and artificial weak negative anomalies form around the positive anomalies in the horizontal direction,resulting in a reduction in the overall resolution.To fully utilize the model weighting function,this study constructs a combined model weighting function.First,a new depth weighting function is constructed by adding a regulator into the conventional depth weighting function to overcome the skin eff ect and inhibit the divergence at the deep area of the inversion results.A horizontal weighting function is then constructed by extracting information from the observation data;this function can suppress the formation of artificial weak anomalies and improve the horizontal resolution of the inversion results.Finally,these two functions are coupled to obtain the combined model weighting function,which can replace the conventional depth weighting function in 3D inversion.It improves the vertical and horizontal resolution of the inversion results without increasing the algorithm complexity and calculation amount,is easy to operate,and adapts to any 3D inversion method.Two model experiments are designed to verify the effectiveness,practicability,and anti-noise of the combined model weighting function.Then the function is applied to the 3D inversion of the measured aeromagnetic data in the Jinchuan area in China.The obtained inversion results are in good agreement with the known geological data.
文摘As an important part of offshore wind turbine support and fixed units, the multibucket jacket foundation bears large loads and a complex marine environment. In this paper, the horizontal bearing characteristics of the four-bucket jacket foundation of offshore wind power in sandy soil are studied. Through model tests and numerical simulations, the influence of bucket foundation sealing properties, load application speed, and loading direction on foundation-bearing capacity are discussed. The results show that the horizontal ultimate bearing capacity of the foundation in the nonsealing condition is decreased by 51.3% compared with the sealing condition;therefore, after the foundation penetration construction is completed, the bucket sealing must be ensured to increase the load-bearing performance of the structure. At a loading speed of 3.25 mm/s, the horizontal ultimate bearing capacity of the foundation is increased by 9.4% over the working condition of 1.85 mm/s. The bearing capacity of the foundation is maximized in the loading direction α =45° and is the smallest when α =0°. That is, the foundation can maximize its loadbearing performance under the condition of single-bucket compression/tension. During the design process, the main load of the structure should be loaded in the 45° direction. The contrast error of the experiment and numerical simulation does not exceed 10%. The research results have important guiding importance for designing and constructing the jacket foundation and can be used as a reference for the stable operation and sustainable development of offshore wind power systems.
基金supported by the National Key Research and Development Program of China(2022YFF0710505)the Central Public-interest Scientific Institution Basal Research Fund,China(1610302022001)。
文摘HighlightsA novel conjugative plasmid pHJ90-cfr carrying the multiresistance gene cfr was characterized in Proteus vulgaris.A new IS5-family member,ISPmi4,was identified for the first time.Both plasmids and ICEs were vital mobile genetic elements for horizontal transmission of cfr gene in Proteus species.
