One-time application of controlled-release blended fertilizer(CRBF,a mixture of five nitrogen(N)fertilizers in a certain ratio)can achieve high yield and N use efficiency(NUE)in rice(Oryza sativa L.).However,the effec...One-time application of controlled-release blended fertilizer(CRBF,a mixture of five nitrogen(N)fertilizers in a certain ratio)can achieve high yield and N use efficiency(NUE)in rice(Oryza sativa L.).However,the effects of CRBF with one-time application on root spatial distribution and physiological characteristics remain unclear.We measured the effects of CRBF with one-time application on rice yield,NUE,root morphology and growth,and N uptake capacity in field and root box experiments.Six N treatments were set up:no nitrogen(N0),high-yield three-split application of urea as a control(CK),urea(U)with broadcast,U with side-deep fertilization,CRBF with broadcast,and CRBF with side-deep fertilization.Our findings showed that root characters were positively correlated with yield and NUE.Compared to CK and U treatments,CRBF with one-time applications increased root characters(including root biomass,root N uptake,root activity,and the expression level of ammonium transporters)at tillering and heading stages.The root length,surface area and volume in the 0-10 cm soil layer enhanced under CRBF with one-time applications at tillering stage,and in the 0-20 cm soil layer at the heading stage.This contributed a5.96%-39.40% and 3.69%-16.87% increase in plant dry matter accumulation and N uptake,and a2.08%-18.28% and 14.60%-149.57% increase in yield and NUE,in 2022 and 2023,respectively.Taken together,our findings showed that one-time application of CRBF could increase rice yield and NUE by optimizing the root morphology distribution and N uptake.展开更多
For the missile with blended aero-fin and lateral impulsive thrust, a blended control autopilot is designed, which comprises an optimal controller and a control allocation module. The combined optimal/classical approa...For the missile with blended aero-fin and lateral impulsive thrust, a blended control autopilot is designed, which comprises an optimal controller and a control allocation module. The combined optimal/classical approach is applied to designing the optimal controller to determine the virtual controls, and the control allocation module is used to distribute the desired vitlual controls onto the redundant control effectors. The autopilot holds some attractive characteristics, such as simple structure, good tracking performance and robustness; moreover the actual constraints of the control effectors can be taken into account. Based on this blended control autopilot, it is found that the conflict between stability and fast tracking performance is serious when using the total acceleration as feedback. In order to avoid this problem, the transient factors in total acceleration are eliminated, so the acceleration caused only by angle of attack is used as feedback, and obvious improvement is shown. Finally, how to get reasonable acceleration feedback is discussed, and conclusion is presented that after passing the low-pass filter, the total acceleration can also be used as feedback, and satisfied tracking performance can be obtained.展开更多
The advanced missile uses blended control of nero-fin and reaction-jet to improve missile maneuverability. The blended control design, which is multi-inputs and multi-outputs （MIMO）, severe nonlinear, and model unce...The advanced missile uses blended control of nero-fin and reaction-jet to improve missile maneuverability. The blended control design, which is multi-inputs and multi-outputs （MIMO）, severe nonlinear, and model uncertain, is much more complex than conventional nero-fin control. A novel nonlinear backstepping control approach is proposed to design the blended autopilot. Missile model is reformed to a new one by state reconstruction technique so that it is easy to be handled by the backstepping method. Then a Lyapunov function is chosen to avoid oscillation caused in normal backstepping way when control parameters are mismatched. In distribution of both inputs, optimal energy logic is proposed. In addition, a fuzzy cerebellar model articulation controller （FCMAC） neural network is used to guarantee controller robustness to uncertainties. Finally, simulation results demonstrate the efficiency and advantages of the proposed method.展开更多
The missile autopilot for an interceptor with tail fins and pulse thrusters is designed via the θ-D approach. The nonlin- ear dynamic model of the pitch and yaw motion of the missile is transformed into a linear-like...The missile autopilot for an interceptor with tail fins and pulse thrusters is designed via the θ-D approach. The nonlin- ear dynamic model of the pitch and yaw motion of the missile is transformed into a linear-like structure with state-dependent coef- ficient （SDC） matrices. Based on the linear-like structure, a θ-D feedback controller is designed to steer the missile to track refer- ence acceleration commands. A sufficient condition that ensures the asymptotic stability of the tracking system is given based on Lyapunov＇s theorem. Numerical results show that the proposed autopilot achieves good tracking performance and the closed-loop tracking system is asymptotically stable.展开更多
With the increase of the interest in solar sailing, it is required to provide a basis for future detailed planetary escape mission analysis by drawing together prior work, clarifying and explaining previously anomalie...With the increase of the interest in solar sailing, it is required to provide a basis for future detailed planetary escape mission analysis by drawing together prior work, clarifying and explaining previously anomalies. In this paper, a technique for escaping the Earth by using a solar sail is developed and numerically simulated. The spacecraft is initially in a geosynchronous transfer orbit (GTO). Blended solar sail analytical control law, explicitly independent of time, are then presented, which provide near-optimal escape trajectories and maintain a safe minimum altitude and which are suitable as a potential autonomous onboard controller. This control law is investigated from a range of initial conditions and is shown to maintain the optimality previously demonstrated by the use of a single-energy gain control law but without the risk of planetary collision. Finally, it is shown that the blending solar sail analytical control law is suitable for solar sail on-board autonomously control system.展开更多
基金supported by the National Key Research and Development Program of China(2023YFD2301304,2022YFD2301404-4,2023YFD2302600,and 2022YFE0116200)Open Subjects of the Key Laboratory of Agro-Environment in the Middle and Lower Yangtze River Plain,Ministry of Agriculture and Rural Affairs of China(2023F12)+1 种基金National Natural Science Foundation of China(32301964)Sanya Yazhou Bay Science and Technology City Project(SKJC-2023-02-004)。
文摘One-time application of controlled-release blended fertilizer(CRBF,a mixture of five nitrogen(N)fertilizers in a certain ratio)can achieve high yield and N use efficiency(NUE)in rice(Oryza sativa L.).However,the effects of CRBF with one-time application on root spatial distribution and physiological characteristics remain unclear.We measured the effects of CRBF with one-time application on rice yield,NUE,root morphology and growth,and N uptake capacity in field and root box experiments.Six N treatments were set up:no nitrogen(N0),high-yield three-split application of urea as a control(CK),urea(U)with broadcast,U with side-deep fertilization,CRBF with broadcast,and CRBF with side-deep fertilization.Our findings showed that root characters were positively correlated with yield and NUE.Compared to CK and U treatments,CRBF with one-time applications increased root characters(including root biomass,root N uptake,root activity,and the expression level of ammonium transporters)at tillering and heading stages.The root length,surface area and volume in the 0-10 cm soil layer enhanced under CRBF with one-time applications at tillering stage,and in the 0-20 cm soil layer at the heading stage.This contributed a5.96%-39.40% and 3.69%-16.87% increase in plant dry matter accumulation and N uptake,and a2.08%-18.28% and 14.60%-149.57% increase in yield and NUE,in 2022 and 2023,respectively.Taken together,our findings showed that one-time application of CRBF could increase rice yield and NUE by optimizing the root morphology distribution and N uptake.
文摘For the missile with blended aero-fin and lateral impulsive thrust, a blended control autopilot is designed, which comprises an optimal controller and a control allocation module. The combined optimal/classical approach is applied to designing the optimal controller to determine the virtual controls, and the control allocation module is used to distribute the desired vitlual controls onto the redundant control effectors. The autopilot holds some attractive characteristics, such as simple structure, good tracking performance and robustness; moreover the actual constraints of the control effectors can be taken into account. Based on this blended control autopilot, it is found that the conflict between stability and fast tracking performance is serious when using the total acceleration as feedback. In order to avoid this problem, the transient factors in total acceleration are eliminated, so the acceleration caused only by angle of attack is used as feedback, and obvious improvement is shown. Finally, how to get reasonable acceleration feedback is discussed, and conclusion is presented that after passing the low-pass filter, the total acceleration can also be used as feedback, and satisfied tracking performance can be obtained.
基金the China Aviation Science Foundation (03D12004)
文摘The advanced missile uses blended control of nero-fin and reaction-jet to improve missile maneuverability. The blended control design, which is multi-inputs and multi-outputs （MIMO）, severe nonlinear, and model uncertain, is much more complex than conventional nero-fin control. A novel nonlinear backstepping control approach is proposed to design the blended autopilot. Missile model is reformed to a new one by state reconstruction technique so that it is easy to be handled by the backstepping method. Then a Lyapunov function is chosen to avoid oscillation caused in normal backstepping way when control parameters are mismatched. In distribution of both inputs, optimal energy logic is proposed. In addition, a fuzzy cerebellar model articulation controller （FCMAC） neural network is used to guarantee controller robustness to uncertainties. Finally, simulation results demonstrate the efficiency and advantages of the proposed method.
基金supported by the National Natural Science Foundation of China(61174203)the Aeronautical Science Foundation of China(20110177002)
文摘The missile autopilot for an interceptor with tail fins and pulse thrusters is designed via the θ-D approach. The nonlin- ear dynamic model of the pitch and yaw motion of the missile is transformed into a linear-like structure with state-dependent coef- ficient （SDC） matrices. Based on the linear-like structure, a θ-D feedback controller is designed to steer the missile to track refer- ence acceleration commands. A sufficient condition that ensures the asymptotic stability of the tracking system is given based on Lyapunov＇s theorem. Numerical results show that the proposed autopilot achieves good tracking performance and the closed-loop tracking system is asymptotically stable.
基金Sponsored by the National Natural Science Foundation of China ( Grant No. 61005060)
文摘With the increase of the interest in solar sailing, it is required to provide a basis for future detailed planetary escape mission analysis by drawing together prior work, clarifying and explaining previously anomalies. In this paper, a technique for escaping the Earth by using a solar sail is developed and numerically simulated. The spacecraft is initially in a geosynchronous transfer orbit (GTO). Blended solar sail analytical control law, explicitly independent of time, are then presented, which provide near-optimal escape trajectories and maintain a safe minimum altitude and which are suitable as a potential autonomous onboard controller. This control law is investigated from a range of initial conditions and is shown to maintain the optimality previously demonstrated by the use of a single-energy gain control law but without the risk of planetary collision. Finally, it is shown that the blending solar sail analytical control law is suitable for solar sail on-board autonomously control system.
