A novel accurate tracking controller is developed for the longitudinal dynamics of Hypersonic Flight Vehicles(HFVs)in the presence of large model uncertainties,external disturbances and actuator nonlinearities.Distinc...A novel accurate tracking controller is developed for the longitudinal dynamics of Hypersonic Flight Vehicles(HFVs)in the presence of large model uncertainties,external disturbances and actuator nonlinearities.Distinct from the state-of-the-art,besides being continuity,no restrictive conditions have been imposed on the HFVs dynamics.The system uncertainties are skillfully handled by being seen as bounded"disturbance terms".In addition,by means of backstepping adaptive technique,the accurate tracking(i.e.tracking errors converge to zero as time approaches infinity)rather than bounded tracking(i.e.tracking errors converge to residual sets)has been achieved.What’s more,the accurate tracking problems for HFVs subject to actuator dead-zone and hysteresis are discussed,respectively.Then,all signals of closed-loop system are verified to be Semi-Global Uniformly Ultimate Boundness(SGUUB).Finally,the efficacy and superiority of the developed control strategy are confirmed by simulation results.展开更多
Based on investigation and research, according to the current actual production of sugarcane, the occurrence dynamics and outbreak causes of important pests and diseases that seriously affect sugarcane production were...Based on investigation and research, according to the current actual production of sugarcane, the occurrence dynamics and outbreak causes of important pests and diseases that seriously affect sugarcane production were summarized, and accurate and efficient green prevention and control technology was put forward according to the occurrence and damage characteristics of important pests and diseases, such as strengthening sugarcane introduction and quarantine, breeding and selecting varieties resistant to diseases and pests, promoting the use of detoxified healthy seedlings vigorously, applying lamp trapping technology on a large scale, scientifically guiding and promoting biological prevention and control technology, practically promoting the precise and efficient application of slow-release long- acting and low toxic pesticides, strengthening field management, spraying pesticides in time at the early stage of a disease, and doing a good job of monitoring and emergency prevention and control of sudden pests.展开更多
With the improvement of seismic observation system, more and more observations indicate that earthquakes may cause seismic velocity change. However, the amplitude and spatial distribution of the velocity variation rem...With the improvement of seismic observation system, more and more observations indicate that earthquakes may cause seismic velocity change. However, the amplitude and spatial distribution of the velocity variation remains a controversial issue. Recent active source monitoring carried out adjacent to Wenchuan Fault Scientific Drilling （WFSD） revealed unambiguous coseismic velocity change associated with a local M8 5.5 earthquake. Here, we carry out forward modeling using two-dimensional spectral element method to further investigate the amplitude and spatial distribution of observed velocity change. The model is well constrained by results from seismic reflection and WFSD coring. Our model strongly suggests that the observed coseismic velocity change is localized within the fault zone with width of ~ 120 m rather than dynamic strong ground shaking. And a velocity decrease of -2.0 % within the fault zone is required to fit the observed travel time delay distribution, which coincides with rock mechanical experiment and theoretical modeling.展开更多
Cardiovascular diseases account for ~40% of global deaths annually. This situation has revealed the urgent need forthe investigation and development of corresponding drugs for pathogenesis due to the complexity of res...Cardiovascular diseases account for ~40% of global deaths annually. This situation has revealed the urgent need forthe investigation and development of corresponding drugs for pathogenesis due to the complexity of researchmethods and detection techniques. An in vitro cardiomyocyte model is commonly used for cardiac drug screeningand disease modeling since it can respond to microphysiological environmental variations through mechanoelectricfeedback. Microfluidic platforms are capable of accurate fluid control and integration with analysis and detectiontechniques. Therefore, various microfluidic platforms (i.e., heart-on-a-chip) have been applied for the reconstruction ofthe physiological environment and detection of signals from cardiomyocytes. They have demonstrated advantages inmimicking the cardiovascular structure and function in vitro and in monitoring electromechanical signals. This reviewpresents a summary of the methods and technologies used to monitor the contractility and electrophysiologicalsignals of cardiomyocytes within microfluidic platforms. Then, applications in common cardiac drug screening andcardiovascular disease modeling are presented, followed by design strategies for enhancing physiology studies. Finally,we discuss prospects in the tissue engineering and sensing techniques of microfluidic platforms.展开更多
The precise spatiotemporal characterization of broadband ultrafast laser beams is essential for accurate laser control and holds significant potential in photochemistry and high-intensity laser physics.Existing method...The precise spatiotemporal characterization of broadband ultrafast laser beams is essential for accurate laser control and holds significant potential in photochemistry and high-intensity laser physics.Existing methods for spatiotemporal characterization,such as frequency-resolved optical gating(FROG)and compressed ultrafast photography(CUP),are often spatially averaged or suffer from limited spatial resolution.展开更多
基金supported by the Natural Science Basic Research Program of Shaanxi Province,China(No.2019JQ-711)。
文摘A novel accurate tracking controller is developed for the longitudinal dynamics of Hypersonic Flight Vehicles(HFVs)in the presence of large model uncertainties,external disturbances and actuator nonlinearities.Distinct from the state-of-the-art,besides being continuity,no restrictive conditions have been imposed on the HFVs dynamics.The system uncertainties are skillfully handled by being seen as bounded"disturbance terms".In addition,by means of backstepping adaptive technique,the accurate tracking(i.e.tracking errors converge to zero as time approaches infinity)rather than bounded tracking(i.e.tracking errors converge to residual sets)has been achieved.What’s more,the accurate tracking problems for HFVs subject to actuator dead-zone and hysteresis are discussed,respectively.Then,all signals of closed-loop system are verified to be Semi-Global Uniformly Ultimate Boundness(SGUUB).Finally,the efficacy and superiority of the developed control strategy are confirmed by simulation results.
基金Supported by Sugar Crop Research System(CARS-170303)Training Project of "Yunling Industry Technology Leading Talent"(2018LJRC56)Special Funds for Construction of Modern Agricultural Industrial Technology System of Yunnan Province(YNGZTX-4-92)
文摘Based on investigation and research, according to the current actual production of sugarcane, the occurrence dynamics and outbreak causes of important pests and diseases that seriously affect sugarcane production were summarized, and accurate and efficient green prevention and control technology was put forward according to the occurrence and damage characteristics of important pests and diseases, such as strengthening sugarcane introduction and quarantine, breeding and selecting varieties resistant to diseases and pests, promoting the use of detoxified healthy seedlings vigorously, applying lamp trapping technology on a large scale, scientifically guiding and promoting biological prevention and control technology, practically promoting the precise and efficient application of slow-release long- acting and low toxic pesticides, strengthening field management, spraying pesticides in time at the early stage of a disease, and doing a good job of monitoring and emergency prevention and control of sudden pests.
基金supported by China Natural Scientific and Technological Support Projects(Wenchuan Fault Scientific Drilling)National Natural Scientific Foundation of China(Grant No.41204047)
文摘With the improvement of seismic observation system, more and more observations indicate that earthquakes may cause seismic velocity change. However, the amplitude and spatial distribution of the velocity variation remains a controversial issue. Recent active source monitoring carried out adjacent to Wenchuan Fault Scientific Drilling （WFSD） revealed unambiguous coseismic velocity change associated with a local M8 5.5 earthquake. Here, we carry out forward modeling using two-dimensional spectral element method to further investigate the amplitude and spatial distribution of observed velocity change. The model is well constrained by results from seismic reflection and WFSD coring. Our model strongly suggests that the observed coseismic velocity change is localized within the fault zone with width of ~ 120 m rather than dynamic strong ground shaking. And a velocity decrease of -2.0 % within the fault zone is required to fit the observed travel time delay distribution, which coincides with rock mechanical experiment and theoretical modeling.
基金supported by the National Natural Science Foundation of China(NO.62371267,62121003)Key R&D Program of Shandong Province(Major innovation project)(2022CXGC020501)+4 种基金Science,Education and Industry Integration Innovation Pilot Project from Qilu University of Technology(Shandong Academy of Sciences)(NO.2022JBZ02-01)Research Leader Studio in Colleges and Universities of Jinan(NO.2021GXRC083)Innovation Team of Organ-on-a-Chip Manufacturing Key Technologies(NO.202333015,Funded by Jinan Science and Technology Bureau)Young Innovative Talents Introduction&Cultivation Program for Colleges and Universities of Shandong Province(Granted by Department of Education of Shandong Province,Sub-Title 1:Innovative Research Team of High-Performance Integrated Device,Sub-Title 2:Innovative Research Team of Advanced Energy Equipment)Shandong Provincial Natural Science Foundation(ZR2023QH405)。
文摘Cardiovascular diseases account for ~40% of global deaths annually. This situation has revealed the urgent need forthe investigation and development of corresponding drugs for pathogenesis due to the complexity of researchmethods and detection techniques. An in vitro cardiomyocyte model is commonly used for cardiac drug screeningand disease modeling since it can respond to microphysiological environmental variations through mechanoelectricfeedback. Microfluidic platforms are capable of accurate fluid control and integration with analysis and detectiontechniques. Therefore, various microfluidic platforms (i.e., heart-on-a-chip) have been applied for the reconstruction ofthe physiological environment and detection of signals from cardiomyocytes. They have demonstrated advantages inmimicking the cardiovascular structure and function in vitro and in monitoring electromechanical signals. This reviewpresents a summary of the methods and technologies used to monitor the contractility and electrophysiologicalsignals of cardiomyocytes within microfluidic platforms. Then, applications in common cardiac drug screening andcardiovascular disease modeling are presented, followed by design strategies for enhancing physiology studies. Finally,we discuss prospects in the tissue engineering and sensing techniques of microfluidic platforms.
基金National Key Research and Development Program of China(2024YFE0205800)National Natural Science Foundation of China(12274158,12021004).
文摘The precise spatiotemporal characterization of broadband ultrafast laser beams is essential for accurate laser control and holds significant potential in photochemistry and high-intensity laser physics.Existing methods for spatiotemporal characterization,such as frequency-resolved optical gating(FROG)and compressed ultrafast photography(CUP),are often spatially averaged or suffer from limited spatial resolution.
