[ Objectlve] Impulsive Logistic Model was used to simulate epidemic process of Gray Leaf Spots caused by C. zeae-maydi. [ Method] The pathogen was inoculated in different maize varieties, and the incidence were observ...[ Objectlve] Impulsive Logistic Model was used to simulate epidemic process of Gray Leaf Spots caused by C. zeae-maydi. [ Method] The pathogen was inoculated in different maize varieties, and the incidence were observed and recorded. Impulsive Logistic Model was used to simulate the development process of the disease, which was compared with actual incidence. [ Result] Artificial inoculation tests showed that impulsive Logistic Model could reflect time dynamic of C. zeae-maydi. Through derivation, exponential growth phase was from maize seedling emergence to eady July in each year, logistic phase was from early July to late August, terminal phase was from eady September to the end of maize growth stage. [ Conclusion] The derivation result from model was consistent with the development biological laws of C. zeae-maydi.展开更多
The impulse waves induced by large-reservoir landslides can be characterized by a low Froude number.However,systematic research on predictive models specifically targeting the initial primary wave is lacking.Taking th...The impulse waves induced by large-reservoir landslides can be characterized by a low Froude number.However,systematic research on predictive models specifically targeting the initial primary wave is lacking.Taking the Shuipingzi 1#landslide that occurred in the Baihetan Reservoir area of the Jinsha River in China as an engineering example,this study established a large-scale physical model(with dimensions of 30 m×29 m×3.5 m at a scale of 1:150)and conducted scaled experiments on 3D landslide-induced impulse waves.During the process in which a sliding mass displaced and compressed a body of water to generate waves,the maximum initial wave amplitude was found to be positively correlated with the sliding velocity and the volume of the landslide.With the increase in the water depth,the wave amplitude initially increased and then decreased.The duration of pressure exertion by the sliding mass at its maximum velocity directly correlated with an elevated wave amplitude.Based on the theories of low-amplitude waves and energy conservation,while considering the energy conversion efficiency,a predictive model for the initial wave amplitude was derived.This model could fit and validate the functions of wavelength and wave velocity.The accuracy of the initial wave amplitude was verified using physical experiment data,with a prediction accuracy for the maximum initial wave amplitude reaching 90%.The conversion efficiency(η)directly determined the accuracy of the estimation formula.Under clear conditions for landslide-induced impulse wave generation,estimating the value ofηthrough analogy cases was feasible.This study has derived the landslide-induced impulse waves amplitude prediction formula from the standpoints of wave theory and energy conservation,with greater consideration given to the intrinsic characteristics in the formation process of landslide-induced impulse waves,thereby enhancing the applicability and extensibility of the formula.This can facilitate the development of empirical estimation methods for landslide-induced impulse waves toward universality.展开更多
This paper mainly studies the stochastic character of tumor growth in the presence of immune response and periodically pulsed chemotherapy.First,a stochastic impulsive model describing the interaction and competition ...This paper mainly studies the stochastic character of tumor growth in the presence of immune response and periodically pulsed chemotherapy.First,a stochastic impulsive model describing the interaction and competition among normal cells,tumor cells and immune cells under periodically pulsed chemotherapy is established.Then,sufficient conditions for the extinction,non-persistence in the mean,weak and strong persistence in the mean of tumor cells are obtained.Finally,numerical simulations are performed which not only verify the theoretical results derived but also reveal some specific features.The results show that the growth trend of tumor cells is significantly affected by the intensity of noise and the frequency and dose of drug deliveries.In clinical practice,doctors can reduce the randomness of the environment and increase the intensity of drug input to inhibit the proliferation and growth of tumor cells.展开更多
The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making co...The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making collision avoidance significantly more challenging than that for space debris.Much existing research focuses on the continuous thrust model,whereas the impulsive maneuver model is more appropriate for long-duration and long-distance avoidance missions.Additionally,it is important to minimize the impact on the original mission while avoiding noncooperative targets.On the other hand,the existing avoidance algorithms are computationally complex and time-consuming especially with the limited computing capability of the on-board computer,posing challenges for practical engineering applications.To conquer these difficulties,this paper makes the following key contributions:(A)a turn-based(sequential decision-making)limited-area impulsive collision avoidance model considering the time delay of precision orbit determination is established for the first time;(B)a novel Selection Probability Learning Adaptive Search-depth Search Tree(SPL-ASST)algorithm is proposed for non-cooperative target avoidance,which improves the decision-making efficiency by introducing an adaptive-search-depth mechanism and a neural network into the traditional Monte Carlo Tree Search(MCTS).Numerical simulations confirm the effectiveness and efficiency of the proposed method.展开更多
This paper is concerned with impulsive Nicholson＇s blowflies model with linear harvesting term. By using contraction mapping fixed point theorem, we obtain sufficient conditions for the existence of unique almost per...This paper is concerned with impulsive Nicholson＇s blowflies model with linear harvesting term. By using contraction mapping fixed point theorem, we obtain sufficient conditions for the existence of unique almost periodic positive solution. Moreover, we investigate exponential convergence of the almost periodic positive solution by Lyapunov functional.展开更多
The dynamic behavior of a cavitation bubble near an asymmetric hydrofoil is investigated experimentally through high-speed photography and theoretically using a Kelvin impulse model.The typical deformations arising du...The dynamic behavior of a cavitation bubble near an asymmetric hydrofoil is investigated experimentally through high-speed photography and theoretically using a Kelvin impulse model.The typical deformations arising during bubble collapse near the hydrofoil are analyzed qualitatively.The effects of the bubble position and the hydrofoil’s eccentricity angle are analyzed quantitatively.The spatial distribution of the Kelvin impulse near the hydrofoil are explored.Different morphological evolutions of a bubble near an asymmetric hydrofoil are revealed,with B-shaped,heart-shaped,and arc-shaped collapses.The velocity of the bubble interface close to the hydrofoil is significantly affected by the bubble-hydrofoil distance and the hydrofoil’s eccentricity angle,increasing as both the distance and the eccentricity angle grow.It is found that the Kelvin impulse sensitivity varies at different positions with respect to the asymmetric hydrofoil,being higher at the head and tail,and lower in the middle.展开更多
The price fluctuation of commodities affects their demand,and it strongly influences the development of industry and the stability of the international economy.A price-output model with two price-dependent impulses is...The price fluctuation of commodities affects their demand,and it strongly influences the development of industry and the stability of the international economy.A price-output model with two price-dependent impulses is presented in this paper to describe their mutual restrictions and the price adjustment strategies.The equilibria and dynamic properties of the impulsive-free price-output model are qualitatively analyzed,and the results show the hazard of free price fluctuation.For the price-output model with two price-dependent impulses,conditions for the existence of the order-2 periodic solution are obtained,and the orbital asymptotic stability is proved.Those results reveal the positive role of price adjustment strategies.Finally,some numerical simulations are carried out to verify the theoretical results.展开更多
基金Supported by Doctoral Fundation of Liaoning Province(20081064)Liaoning BaiQianWan Talents Program(2009921072)Ministry of Agriculture,National Research Subject(2004BA520A11)~~
文摘[ Objectlve] Impulsive Logistic Model was used to simulate epidemic process of Gray Leaf Spots caused by C. zeae-maydi. [ Method] The pathogen was inoculated in different maize varieties, and the incidence were observed and recorded. Impulsive Logistic Model was used to simulate the development process of the disease, which was compared with actual incidence. [ Result] Artificial inoculation tests showed that impulsive Logistic Model could reflect time dynamic of C. zeae-maydi. Through derivation, exponential growth phase was from maize seedling emergence to eady July in each year, logistic phase was from early July to late August, terminal phase was from eady September to the end of maize growth stage. [ Conclusion] The derivation result from model was consistent with the development biological laws of C. zeae-maydi.
基金The authors would like thank LI Renjiang and HU Bin from the China Three Gorges Corporation for providing many valuable suggestions for the establishment of the physical models.This work was supported by the National Natural Science Foundation of China(No.U23A2045)the China Three Gorges Corporation(YM(BHT)/(22)022)the Scientific Research Project of Chongqing Municipal Bureau of Planning and Natural Resources(Evaluation and Reinforcement Technology of Surge Disaster Caused by High and Steep Dangerous Rocks in Chongqing Reservoir Area of the Three Gorges Project,KJ-2023046).
文摘The impulse waves induced by large-reservoir landslides can be characterized by a low Froude number.However,systematic research on predictive models specifically targeting the initial primary wave is lacking.Taking the Shuipingzi 1#landslide that occurred in the Baihetan Reservoir area of the Jinsha River in China as an engineering example,this study established a large-scale physical model(with dimensions of 30 m×29 m×3.5 m at a scale of 1:150)and conducted scaled experiments on 3D landslide-induced impulse waves.During the process in which a sliding mass displaced and compressed a body of water to generate waves,the maximum initial wave amplitude was found to be positively correlated with the sliding velocity and the volume of the landslide.With the increase in the water depth,the wave amplitude initially increased and then decreased.The duration of pressure exertion by the sliding mass at its maximum velocity directly correlated with an elevated wave amplitude.Based on the theories of low-amplitude waves and energy conservation,while considering the energy conversion efficiency,a predictive model for the initial wave amplitude was derived.This model could fit and validate the functions of wavelength and wave velocity.The accuracy of the initial wave amplitude was verified using physical experiment data,with a prediction accuracy for the maximum initial wave amplitude reaching 90%.The conversion efficiency(η)directly determined the accuracy of the estimation formula.Under clear conditions for landslide-induced impulse wave generation,estimating the value ofηthrough analogy cases was feasible.This study has derived the landslide-induced impulse waves amplitude prediction formula from the standpoints of wave theory and energy conservation,with greater consideration given to the intrinsic characteristics in the formation process of landslide-induced impulse waves,thereby enhancing the applicability and extensibility of the formula.This can facilitate the development of empirical estimation methods for landslide-induced impulse waves toward universality.
基金supported by the National Natural Science Foundation of China(12071407,11901502)Training plan for young backbone teachers in Henan Province(2019GGJS157)+3 种基金Foundation of Henan Educational Committee under Contract(21A110022)Program for Science&Technology Innovation Talents in Universities of Henan Province(21HASTIT026)Scientific and Technological Key Projects of Henan Province(212102110025)Nanhu Scholars Program for Young Scholars of XYNU。
文摘This paper mainly studies the stochastic character of tumor growth in the presence of immune response and periodically pulsed chemotherapy.First,a stochastic impulsive model describing the interaction and competition among normal cells,tumor cells and immune cells under periodically pulsed chemotherapy is established.Then,sufficient conditions for the extinction,non-persistence in the mean,weak and strong persistence in the mean of tumor cells are obtained.Finally,numerical simulations are performed which not only verify the theoretical results derived but also reveal some specific features.The results show that the growth trend of tumor cells is significantly affected by the intensity of noise and the frequency and dose of drug deliveries.In clinical practice,doctors can reduce the randomness of the environment and increase the intensity of drug input to inhibit the proliferation and growth of tumor cells.
基金co-supported by the Foundation of Shanghai Astronautics Science and Technology Innovation,China(No.SAST2022-114)the National Natural Science Foundation of China(No.62303378),the National Natural Science Foundation of China(Nos.124B2031,12202281)the Foundation of China National Key Laboratory of Science and Technology on Test Physics&Numerical Mathematics,China(No.08-YY-2023-R11)。
文摘The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making collision avoidance significantly more challenging than that for space debris.Much existing research focuses on the continuous thrust model,whereas the impulsive maneuver model is more appropriate for long-duration and long-distance avoidance missions.Additionally,it is important to minimize the impact on the original mission while avoiding noncooperative targets.On the other hand,the existing avoidance algorithms are computationally complex and time-consuming especially with the limited computing capability of the on-board computer,posing challenges for practical engineering applications.To conquer these difficulties,this paper makes the following key contributions:(A)a turn-based(sequential decision-making)limited-area impulsive collision avoidance model considering the time delay of precision orbit determination is established for the first time;(B)a novel Selection Probability Learning Adaptive Search-depth Search Tree(SPL-ASST)algorithm is proposed for non-cooperative target avoidance,which improves the decision-making efficiency by introducing an adaptive-search-depth mechanism and a neural network into the traditional Monte Carlo Tree Search(MCTS).Numerical simulations confirm the effectiveness and efficiency of the proposed method.
基金The author thanks the referees for their valuable comments and suggestions in improving the presentation of the paper. This work is supported by Natural Science Foundation of Education Department of Anhui Province （KJ2014A043）.
文摘This paper is concerned with impulsive Nicholson＇s blowflies model with linear harvesting term. By using contraction mapping fixed point theorem, we obtain sufficient conditions for the existence of unique almost periodic positive solution. Moreover, we investigate exponential convergence of the almost periodic positive solution by Lyapunov functional.
基金supported by the National Natural Science Foundation of China(Project No.51976056).
文摘The dynamic behavior of a cavitation bubble near an asymmetric hydrofoil is investigated experimentally through high-speed photography and theoretically using a Kelvin impulse model.The typical deformations arising during bubble collapse near the hydrofoil are analyzed qualitatively.The effects of the bubble position and the hydrofoil’s eccentricity angle are analyzed quantitatively.The spatial distribution of the Kelvin impulse near the hydrofoil are explored.Different morphological evolutions of a bubble near an asymmetric hydrofoil are revealed,with B-shaped,heart-shaped,and arc-shaped collapses.The velocity of the bubble interface close to the hydrofoil is significantly affected by the bubble-hydrofoil distance and the hydrofoil’s eccentricity angle,increasing as both the distance and the eccentricity angle grow.It is found that the Kelvin impulse sensitivity varies at different positions with respect to the asymmetric hydrofoil,being higher at the head and tail,and lower in the middle.
基金This work is supported by the National Natural Science Foundation of China(No.11701026,No.12071407)the Fundaineiital Researcli Funds of Beijing University of Civil Engineering and Architecture(No.X18225,No.XI9031)the Post Graduate Innovation Project of Beijing University of Civil Engineering and Architecture(No.PG2020098).
文摘The price fluctuation of commodities affects their demand,and it strongly influences the development of industry and the stability of the international economy.A price-output model with two price-dependent impulses is presented in this paper to describe their mutual restrictions and the price adjustment strategies.The equilibria and dynamic properties of the impulsive-free price-output model are qualitatively analyzed,and the results show the hazard of free price fluctuation.For the price-output model with two price-dependent impulses,conditions for the existence of the order-2 periodic solution are obtained,and the orbital asymptotic stability is proved.Those results reveal the positive role of price adjustment strategies.Finally,some numerical simulations are carried out to verify the theoretical results.
