Salinization of agricultural land is becoming increasingly severe worldwide,posing a significant threat to food security.The exogenous application of bioactive substances has been widely used to enhance plant resistan...Salinization of agricultural land is becoming increasingly severe worldwide,posing a significant threat to food security.The exogenous application of bioactive substances has been widely used to enhance plant resistance to salt stress.In this study,we used corn steep liquor(CSL),myo-inositol(MI),and their combination to improve salt tolerance in Chinese cabbage(Brassica rapa L.ssp.pekinensis)under salt stress conditions.All three treatments significantly increased plant biomass and nutrient uptake,and improved soil physicochemical properties,while alleviating oxidative damage and ion toxicity.展开更多
The coupling effects of rainfall,earthquake,and complex topographic and geological conditions complicate the dynamic responses and disasters of slope-tunnel systems.For this,the large-scale shaking table tests were ca...The coupling effects of rainfall,earthquake,and complex topographic and geological conditions complicate the dynamic responses and disasters of slope-tunnel systems.For this,the large-scale shaking table tests were carried out to explore the dynamic responses of steep bedding slope-tunnel system under the coupling effect of rainfall and earthquake.Results show that the slope surface and elevation amplification effect exhibit pronounced nonlinear change caused by the tunnel and weak interlayers.When seismic wave propagates to tunnels,the weak interlayers and rock intersecting areas present complex wave field distribution characteristics.The dynamic responses of the slope are influenced by the frequency,amplitude,and direction of seismic waves.The acceleration amplification coefficient initially rises and then falls as increasing seismic frequency,peaking at 20 Hz.Additionally,the seismic damage process of slope is categorized into elastic(2-3 m/s^(2)),elastoplastic(4-5 m/s^(2))and plastic damage stages(≥6.5 m/s^(2)).In elastic stage,ΔMPGA(ratio of acceleration amplification factor)increases with increasing seismic intensity,without obvious strain distribution change.In plastic stage,ΔMPGA begins to gradually plummet,and the strain is mainly distributed in the damaged area.The modes of seismic damage in the slope-tunnel system are mainly of tensile failure of the weak interlayer,cracking failure of tunnel lining,formation of persistent cracks on the slope crest and waist,development and outward shearing of the sliding mass,and buckling failure at the slope foot under extrusion of the upper rock body.This study can serve as a reference for predicting the failure modes of tunnel-slope system in strong seismic regions.展开更多
In this paper,we investigate the following fractional Schrödinger-Poisson system with concave-convex nonlinearities and a steep potential well{(-Δ)^(s)u+V_(λ)(x)u+ϕu=f(x)|u|^(q-2)u+|u|^(p-2)u,in R^(3),(-Δ)^(t)...In this paper,we investigate the following fractional Schrödinger-Poisson system with concave-convex nonlinearities and a steep potential well{(-Δ)^(s)u+V_(λ)(x)u+ϕu=f(x)|u|^(q-2)u+|u|^(p-2)u,in R^(3),(-Δ)^(t)ϕ=u^(2),in R^(3),where s∈(3/4,1),t∈(0,1),q∈(1,2),p∈(4,2_(s)^(*)),2_(s)^(*):=6/3-2s is the fractional critical exponent in dimension 3,V_(λ)(x)=λV(x)+1 withλ>0.Under the case of steep potential well,we obtain the existence of the sign-changing solutions for the above system by using the constraint variational method and the quantitative deformation lemma.Furthermore,we prove that the energy of ground state sign-changing solution is strictly more than twice of the energy of the ground state solution.Our results improve the recent results in the literature.展开更多
The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of ...The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of Navier slip conditions on exchange flows within a long channel connecting two large reservoirs of differing salinity.These horizontal density gradients drive the flow.We modify the recent one-dimensional theory,developed to avoid runaway stratification,to account for the presence of uniform slip walls.By adjusting the parameters of the horizontal density gradient based on the slip factor,we resolve analytically various flow regimes ranging from high diffusion to transitional high advection.These regimes are governed by physical parameters like channel aspect ratio,slip factor,Schmidt number,and gravitational Reynolds number.Our solutions align perfectly with ones in the no-slip limit.More importantly,under the conditions of no net flow across the channel and high Schmidt number(where stratification is concentrated near the channel’s mid-layer),we derive a closed-form solution for the slip parameter,aspect ratio,and gravitational Reynolds number that describes the interface’s behavior as a sharp interface separating two distinct zones.This interface,arising from hydrostatic wall gradients,ultimately detaches the low-and high-density regimes throughout the channel when the gravitational Reynolds number is inversely proportional to the aspect ratio for a fixed slip parameter.This phenomenon,observed previously in 2D numerical simulations with no-slip walls in the literature,is thus confirmed by our theoretical results.Our findings further demonstrate that wall slip leads to distinct and diverse flow regimes.展开更多
This study investigates the bifurcation dynamics underlying rhythmic transitions in a biophysical hippocampal–cortical neural network model.We specifically focus on the membrane potential dynamics of excitatory neuro...This study investigates the bifurcation dynamics underlying rhythmic transitions in a biophysical hippocampal–cortical neural network model.We specifically focus on the membrane potential dynamics of excitatory neurons in the hippocampal CA3 region and examine how strong coupling parameters modulate memory consolidation processes.Employing bifurcation analysis,we systematically characterize the model's complex dynamical behaviors.Subsequently,a characteristic waveform recognition algorithm enables precise feature extraction and automated detection of hippocampal sharp-wave ripples(SWRs).Our results demonstrate that neuronal rhythms exhibit a propensity for abrupt transitions near bifurcation points,facilitating the emergence of SWRs.Critically,temporal rhythmic analysis reveals that the occurrence of a bifurcation is not always sufficient for SWR formation.By integrating one-parameter bifurcation analysis with extremum analysis,we demonstrate that large-amplitude membrane potential oscillations near bifurcation points are highly conducive to SWR generation.This research elucidates the mechanistic link between changes in neuronal self-connection parameters and the evolution of rhythmic characteristics,providing deeper insights into the role of dynamical behavior in memory consolidation.展开更多
0 INTRODUCTION Geohazards in mountainous regions pose significant risks to the construction and safe operation of transportation,water conservancy,and other critical infrastructure projects.Engineering geological inve...0 INTRODUCTION Geohazards in mountainous regions pose significant risks to the construction and safe operation of transportation,water conservancy,and other critical infrastructure projects.Engineering geological investigations are crucial for disaster prevention and mitigation.展开更多
Aiming at the gas discharge problem in electric aircraft,this work studies the gas discharge characteristics at low-temperature sub-atmospheric pressure.A gas discharge shooting platform was built,and the discharge pr...Aiming at the gas discharge problem in electric aircraft,this work studies the gas discharge characteristics at low-temperature sub-atmospheric pressure.A gas discharge shooting platform was built,and the discharge process was photographed by intensified charge-coupled device(ICCD).A two-dimensional axisymmetric model of needle-plate electrode gas discharge was established,and three sets of Helmholtz equations were used to solve the photoionization.The results show that under the same voltage,the electric field intensity in the discharge process increases first,then decreases and finally increases again.The discharge speed increases with the increase of altitude,and the electron density in the streamer decreases with the increase of altitude.The development speed of the streamer in the middle stage is higher than that in the early stage,and the speed increases more obviously with the increase of altitude.The development speed of the streamer in the later stage is lower than that in the middle stage,but with the increase of altitude,the development speed of the streamer in the later stage is higher than that in the middle stage.展开更多
Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Ou...Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Our collaborative team has developed a novel,efficient,and low-toxicity fungicide named Y17991(N-(2-(2,4-bis-(trifluoromethyl)phenoxy)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide).Preliminary laboratory tests confirmed the significant inhibitory effect of this agent on R.cerealis.Large-area field trials also demonstrated its efficacy,with a disease prevention index of 83.52%,which is 1.97%greater than that of the widely used thifluzamide,and it significantly increased the wheat yield.Moreover,this study explored the impacts of Y17991 on the structure and function of the microbial community in wheat rhizosphere soil.Bacterial communities were more strongly affected than fungal communities.Y17991 significantly modulated key amino acid metabolic pathways and certain biosynthetic processes in diseased wheat rhizospheres,and it also enhanced certain biosynthetic pathways and metabolic activities in healthy wheat rhizospheres.Additionally,the application of Y17991 regulated rhizosphere metabolites,thus exerting significant control over the microbial community.We identified 15 microbial strains potentially involved in the prevention and treatment of R.cerealis,and Y17991 treatment promoted the growth of Pedobacter and Bacillus strains.These strains not only aid in plant growth but they also have the potential for disease prevention.In summary,Y17991 application at a reasonable dose does not cause significant disruption to nontarget rhizosphere microbial communities.In future studies,we will continue to investigate the impacts of Y17991 on nonmicrobial components in soil ecosystems,such as protozoa and nematodes.Our research provides a theoretical basis for the scientific application and promotion of new fungicides and offers a significant reference for establishing a comprehensive system for assessing the ecological impact of pesticides on the environment.展开更多
基金supported by the sub-project“Research and Application of In-Situ Value-Added Water-Soluble Fertilizer Application Technology”(Grant No.2023YFD1700204-3)under the 14th Five-Year National Key R&D Program Project“Development and Industrialization of Novel Green Value-Added Fertilizers”.
文摘Salinization of agricultural land is becoming increasingly severe worldwide,posing a significant threat to food security.The exogenous application of bioactive substances has been widely used to enhance plant resistance to salt stress.In this study,we used corn steep liquor(CSL),myo-inositol(MI),and their combination to improve salt tolerance in Chinese cabbage(Brassica rapa L.ssp.pekinensis)under salt stress conditions.All three treatments significantly increased plant biomass and nutrient uptake,and improved soil physicochemical properties,while alleviating oxidative damage and ion toxicity.
基金supported by the National Natural Science Foundation of China (Grant No.52109125)the Natural Science Foundation of Jiangsu Province,China (Grant No.BK20231217)the Key Laboratory of Geomechanics and Geotechnical Engineering Safety,Chinese Academy of Sciences (Grant No.SKLGME023001).
文摘The coupling effects of rainfall,earthquake,and complex topographic and geological conditions complicate the dynamic responses and disasters of slope-tunnel systems.For this,the large-scale shaking table tests were carried out to explore the dynamic responses of steep bedding slope-tunnel system under the coupling effect of rainfall and earthquake.Results show that the slope surface and elevation amplification effect exhibit pronounced nonlinear change caused by the tunnel and weak interlayers.When seismic wave propagates to tunnels,the weak interlayers and rock intersecting areas present complex wave field distribution characteristics.The dynamic responses of the slope are influenced by the frequency,amplitude,and direction of seismic waves.The acceleration amplification coefficient initially rises and then falls as increasing seismic frequency,peaking at 20 Hz.Additionally,the seismic damage process of slope is categorized into elastic(2-3 m/s^(2)),elastoplastic(4-5 m/s^(2))and plastic damage stages(≥6.5 m/s^(2)).In elastic stage,ΔMPGA(ratio of acceleration amplification factor)increases with increasing seismic intensity,without obvious strain distribution change.In plastic stage,ΔMPGA begins to gradually plummet,and the strain is mainly distributed in the damaged area.The modes of seismic damage in the slope-tunnel system are mainly of tensile failure of the weak interlayer,cracking failure of tunnel lining,formation of persistent cracks on the slope crest and waist,development and outward shearing of the sliding mass,and buckling failure at the slope foot under extrusion of the upper rock body.This study can serve as a reference for predicting the failure modes of tunnel-slope system in strong seismic regions.
基金supported by the Natural Science Foundation of Sichuan(No.2023NSFSC0073)。
文摘In this paper,we investigate the following fractional Schrödinger-Poisson system with concave-convex nonlinearities and a steep potential well{(-Δ)^(s)u+V_(λ)(x)u+ϕu=f(x)|u|^(q-2)u+|u|^(p-2)u,in R^(3),(-Δ)^(t)ϕ=u^(2),in R^(3),where s∈(3/4,1),t∈(0,1),q∈(1,2),p∈(4,2_(s)^(*)),2_(s)^(*):=6/3-2s is the fractional critical exponent in dimension 3,V_(λ)(x)=λV(x)+1 withλ>0.Under the case of steep potential well,we obtain the existence of the sign-changing solutions for the above system by using the constraint variational method and the quantitative deformation lemma.Furthermore,we prove that the energy of ground state sign-changing solution is strictly more than twice of the energy of the ground state solution.Our results improve the recent results in the literature.
文摘The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of Navier slip conditions on exchange flows within a long channel connecting two large reservoirs of differing salinity.These horizontal density gradients drive the flow.We modify the recent one-dimensional theory,developed to avoid runaway stratification,to account for the presence of uniform slip walls.By adjusting the parameters of the horizontal density gradient based on the slip factor,we resolve analytically various flow regimes ranging from high diffusion to transitional high advection.These regimes are governed by physical parameters like channel aspect ratio,slip factor,Schmidt number,and gravitational Reynolds number.Our solutions align perfectly with ones in the no-slip limit.More importantly,under the conditions of no net flow across the channel and high Schmidt number(where stratification is concentrated near the channel’s mid-layer),we derive a closed-form solution for the slip parameter,aspect ratio,and gravitational Reynolds number that describes the interface’s behavior as a sharp interface separating two distinct zones.This interface,arising from hydrostatic wall gradients,ultimately detaches the low-and high-density regimes throughout the channel when the gravitational Reynolds number is inversely proportional to the aspect ratio for a fixed slip parameter.This phenomenon,observed previously in 2D numerical simulations with no-slip walls in the literature,is thus confirmed by our theoretical results.Our findings further demonstrate that wall slip leads to distinct and diverse flow regimes.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272002 and 12372061)the R&D Program of Beijing Municipal Education Commission(Grant No.KM202310009004)+1 种基金the North China University of Technology(Grant No.2023XN075-01)the Youth Research Special Project of the North China University of Technology(Grant No.2025NCUTYRSP051)。
文摘This study investigates the bifurcation dynamics underlying rhythmic transitions in a biophysical hippocampal–cortical neural network model.We specifically focus on the membrane potential dynamics of excitatory neurons in the hippocampal CA3 region and examine how strong coupling parameters modulate memory consolidation processes.Employing bifurcation analysis,we systematically characterize the model's complex dynamical behaviors.Subsequently,a characteristic waveform recognition algorithm enables precise feature extraction and automated detection of hippocampal sharp-wave ripples(SWRs).Our results demonstrate that neuronal rhythms exhibit a propensity for abrupt transitions near bifurcation points,facilitating the emergence of SWRs.Critically,temporal rhythmic analysis reveals that the occurrence of a bifurcation is not always sufficient for SWR formation.By integrating one-parameter bifurcation analysis with extremum analysis,we demonstrate that large-amplitude membrane potential oscillations near bifurcation points are highly conducive to SWR generation.This research elucidates the mechanistic link between changes in neuronal self-connection parameters and the evolution of rhythmic characteristics,providing deeper insights into the role of dynamical behavior in memory consolidation.
基金financially supported by the National Key R&D Program of China(No.2022YFC3080200)。
文摘0 INTRODUCTION Geohazards in mountainous regions pose significant risks to the construction and safe operation of transportation,water conservancy,and other critical infrastructure projects.Engineering geological investigations are crucial for disaster prevention and mitigation.
文摘Aiming at the gas discharge problem in electric aircraft,this work studies the gas discharge characteristics at low-temperature sub-atmospheric pressure.A gas discharge shooting platform was built,and the discharge process was photographed by intensified charge-coupled device(ICCD).A two-dimensional axisymmetric model of needle-plate electrode gas discharge was established,and three sets of Helmholtz equations were used to solve the photoionization.The results show that under the same voltage,the electric field intensity in the discharge process increases first,then decreases and finally increases again.The discharge speed increases with the increase of altitude,and the electron density in the streamer decreases with the increase of altitude.The development speed of the streamer in the middle stage is higher than that in the early stage,and the speed increases more obviously with the increase of altitude.The development speed of the streamer in the later stage is lower than that in the middle stage,but with the increase of altitude,the development speed of the streamer in the later stage is higher than that in the middle stage.
基金supported by the National Natural Science Foundation of China(32270296)the Shenzhen Postdoctoral Scientific Research,China(77000-42100004)+1 种基金the Key Basic Research and Development Program of Hubei Province,China(2020BBA052)the Natural Science Foundation of Guangdong Province,China(2024A1515010498)and the Fundamental Research Funds for the Central Universities,Sun Yat-sen University,China.
文摘Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Our collaborative team has developed a novel,efficient,and low-toxicity fungicide named Y17991(N-(2-(2,4-bis-(trifluoromethyl)phenoxy)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide).Preliminary laboratory tests confirmed the significant inhibitory effect of this agent on R.cerealis.Large-area field trials also demonstrated its efficacy,with a disease prevention index of 83.52%,which is 1.97%greater than that of the widely used thifluzamide,and it significantly increased the wheat yield.Moreover,this study explored the impacts of Y17991 on the structure and function of the microbial community in wheat rhizosphere soil.Bacterial communities were more strongly affected than fungal communities.Y17991 significantly modulated key amino acid metabolic pathways and certain biosynthetic processes in diseased wheat rhizospheres,and it also enhanced certain biosynthetic pathways and metabolic activities in healthy wheat rhizospheres.Additionally,the application of Y17991 regulated rhizosphere metabolites,thus exerting significant control over the microbial community.We identified 15 microbial strains potentially involved in the prevention and treatment of R.cerealis,and Y17991 treatment promoted the growth of Pedobacter and Bacillus strains.These strains not only aid in plant growth but they also have the potential for disease prevention.In summary,Y17991 application at a reasonable dose does not cause significant disruption to nontarget rhizosphere microbial communities.In future studies,we will continue to investigate the impacts of Y17991 on nonmicrobial components in soil ecosystems,such as protozoa and nematodes.Our research provides a theoretical basis for the scientific application and promotion of new fungicides and offers a significant reference for establishing a comprehensive system for assessing the ecological impact of pesticides on the environment.
