This paper describes the study of a powered-coast-powered guidance recon¯guration(PCPGR)method used to solve the autonomous rescue problem for the mission pro¯le of a launch vehicle with a coasting phase whe...This paper describes the study of a powered-coast-powered guidance recon¯guration(PCPGR)method used to solve the autonomous rescue problem for the mission pro¯le of a launch vehicle with a coasting phase when the thrust drop fault occurs in the¯rst powered phase(FPP)of the¯nal stage.We¯rst described the constraints of the¯nal stage and the construction of the PCP guidance problem.Then we evaluated the adaptability of the guidance recon¯guration(GR)o®line with numerical optimization by adjusting the constraints of the FPP,the coast phase,and the second powered phase.To determine the fault state set where the rocket can enter the prescribed target orbit through the GR initiate,we proposed a Newton method-based rapid replanning method of the transfer orbit that transforms the complex multi-°ight phase trajectory planning problem into a feasible transfer orbit search problem to produce a fast solution onboard.Combined with the adaptive adjustment of the coasting time and the iterative guidance mode,we realized the autonomous online rescue of the payload.The simulation results showed that the proposed method achieved a reliable and rapid solution and improved a launch vehicle's adaptability to a thrust drop fault.展开更多
Taking the control detailed planning of Suning Agricultural Sci-Tech Ecological Demonstration Park in Hebei Province for example,general methods for the planning of modern agricultural sci-tech parks were introduced f...Taking the control detailed planning of Suning Agricultural Sci-Tech Ecological Demonstration Park in Hebei Province for example,general methods for the planning of modern agricultural sci-tech parks were introduced from the perspective of general situation of the planning area,technical routes,guiding concepts and planning principles,ecological greening and plant confi guration of the parks was discussed.展开更多
With the gradual improvement of living standard, the public demands on landscaping have focused more on quality than on quantity, and plant furnishing has grown from singular green plants to colored-leaf plants with m...With the gradual improvement of living standard, the public demands on landscaping have focused more on quality than on quantity, and plant furnishing has grown from singular green plants to colored-leaf plants with multiple layers. Confi guration of colored-leaf plants follows certain principles and patterns to enrich the beauty of plant landscaping, construct colorful urban green spaces, satisfy increasing application and aesthetic needs of the public, and reflect value of plant landscaping.展开更多
Some multimodal signals-that is,occurring in more than one sensory modality-appear to carry additional information which is not present when component signals are presented separately.To understand the function of mal...Some multimodal signals-that is,occurring in more than one sensory modality-appear to carry additional information which is not present when component signals are presented separately.To understand the function of male ring dove’s(Streptopelia risoria)multimodal courtship,we used audiovisual playback of male displays to investigate female response to stimuli differing in their audiovisual timing.From natural courtship recordings,we created a shifted stimulus where audio was shifted relative to video by afixed value and a jittered stimulus,where each call was moved randomly along the visual channel.We presented 3 groups of females with the same stimulus type,that is,control,shifted,and jittered,for 7 days.We recorded their behavior and assessed pre-and post-test blood estradiol concentration.We found that playback exposure increased estradiol levels,confirming that this technique can be efficiently used to study doves’sexual communication.Additionally,chasing behavior(indicating sexual stimulation)increased over experimental days only in the control condition,suggesting a role of multimodal timing on female response.This stresses the importance of signal configuration in multimodal communication,as additional information is likely to be contained in the temporal association between modalities.展开更多
基金supported by the National Nature Science Foundation of China(Grant No.62173301)the Young Elite Scientist Sponsorship Program by CAST(Grant No.YESS2000021).
文摘This paper describes the study of a powered-coast-powered guidance recon¯guration(PCPGR)method used to solve the autonomous rescue problem for the mission pro¯le of a launch vehicle with a coasting phase when the thrust drop fault occurs in the¯rst powered phase(FPP)of the¯nal stage.We¯rst described the constraints of the¯nal stage and the construction of the PCP guidance problem.Then we evaluated the adaptability of the guidance recon¯guration(GR)o®line with numerical optimization by adjusting the constraints of the FPP,the coast phase,and the second powered phase.To determine the fault state set where the rocket can enter the prescribed target orbit through the GR initiate,we proposed a Newton method-based rapid replanning method of the transfer orbit that transforms the complex multi-°ight phase trajectory planning problem into a feasible transfer orbit search problem to produce a fast solution onboard.Combined with the adaptive adjustment of the coasting time and the iterative guidance mode,we realized the autonomous online rescue of the payload.The simulation results showed that the proposed method achieved a reliable and rapid solution and improved a launch vehicle's adaptability to a thrust drop fault.
文摘Taking the control detailed planning of Suning Agricultural Sci-Tech Ecological Demonstration Park in Hebei Province for example,general methods for the planning of modern agricultural sci-tech parks were introduced from the perspective of general situation of the planning area,technical routes,guiding concepts and planning principles,ecological greening and plant confi guration of the parks was discussed.
基金Sponsored by National Social Science Foundation of China(14BZX084)Teachers’Professional Ethics Education and Research Base of Hunan Provincial Institutes of Higher Education
文摘With the gradual improvement of living standard, the public demands on landscaping have focused more on quality than on quantity, and plant furnishing has grown from singular green plants to colored-leaf plants with multiple layers. Confi guration of colored-leaf plants follows certain principles and patterns to enrich the beauty of plant landscaping, construct colorful urban green spaces, satisfy increasing application and aesthetic needs of the public, and reflect value of plant landscaping.
基金supported by Leonida Fusani’s Startup funding of the University of Vienna,Austria,by the Austrian Science Fund(FWF),W1262-B29by the Vienna Science and Technology Fund(WWTF)CS18-021。
文摘Some multimodal signals-that is,occurring in more than one sensory modality-appear to carry additional information which is not present when component signals are presented separately.To understand the function of male ring dove’s(Streptopelia risoria)multimodal courtship,we used audiovisual playback of male displays to investigate female response to stimuli differing in their audiovisual timing.From natural courtship recordings,we created a shifted stimulus where audio was shifted relative to video by afixed value and a jittered stimulus,where each call was moved randomly along the visual channel.We presented 3 groups of females with the same stimulus type,that is,control,shifted,and jittered,for 7 days.We recorded their behavior and assessed pre-and post-test blood estradiol concentration.We found that playback exposure increased estradiol levels,confirming that this technique can be efficiently used to study doves’sexual communication.Additionally,chasing behavior(indicating sexual stimulation)increased over experimental days only in the control condition,suggesting a role of multimodal timing on female response.This stresses the importance of signal configuration in multimodal communication,as additional information is likely to be contained in the temporal association between modalities.
