Objective: To evaluate the role of prevention and control strategies for nosocomial infection in a tertiary teaching hospital during the sudden outbreak of Corona Virus Disease 2019 (COVID-19). Methods: The hospital i...Objective: To evaluate the role of prevention and control strategies for nosocomial infection in a tertiary teaching hospital during the sudden outbreak of Corona Virus Disease 2019 (COVID-19). Methods: The hospital initiated an emergency plan involving multi-departmental defense and control. It adopted a series of nosocomial infection prevention and control measures, including strengthening pre-examination and triage, optimizing the consultation process, improving the hospital’s architectural composition, implementing graded risk management, enhancing personal protection, and implementing staff training and supervision. Descriptive research was used to evaluate the short-term effects of these in-hospital prevention and control strategies. The analysis compared changes in related evaluation indicators between January 24, 2020 and February 12, 2020 (Chinese Lunar New Year’s Eve 2020 to lunar January 19) and the corresponding lunar period of the previous year. Results: Compared to the same period last year, the outpatient fever rate increased by 1.85-fold (P P Conclusion: The nosocomial infection prevention and control strategies implemented during this specific period improved the detection and control abilities for the COVID-19 source of infection and enhanced the compliance with measures. This likely contributed significantly to avoiding the occurrence of nosocomial infection.展开更多
Osteoporosis is a common bone disease in women worldwide, leading to decreased bone density and an accelerated risk of fractures. The causes of osteoporosis in women include age (senile osteoporosis), menopause-associ...Osteoporosis is a common bone disease in women worldwide, leading to decreased bone density and an accelerated risk of fractures. The causes of osteoporosis in women include age (senile osteoporosis), menopause-associated hormonal changes, deficiencies in calcium and vitamin D, genetics, lifestyle factors, medical conditions, and some type of medications. The consequences of osteoporosis are colossal, consisting of fractures, decreased quality of life, psychological impacts, and economic burden. To effectively control the menace of osteoporosis in women, numerous strategies are advocated. Adequate calcium and vitamin D consumption through diet or supplements is vital. Regular weight-bearing activities and strength training that promote bone density. Maintaining a healthy life-style through avoiding smoking, limiting alcohol in-take and maintaining a wholesome body weight is essential. Hormone replacement therapy and some medications may be recommended in certain cases. Early detection through regular bone density and blood tests is crucial to lowering its impact. Creating a supportive network through educational programs and resources fosters awareness and empowerment. By engaging these strategies, women can be empowered to combat osteoporosis, reduce fracture risk, and build stronger bones for their overall well-being.展开更多
While presenting biological characteristics of vaccinia virus and laboratory-acquired infections during related research processes, this paper focuses on benefits and risks of vaccinia virus immunization in relation t...While presenting biological characteristics of vaccinia virus and laboratory-acquired infections during related research processes, this paper focuses on benefits and risks of vaccinia virus immunization in relation to laboratory-acquired infections, describes characteristics and the adaptation of vaccinia virus vaccine, analyses the role vaccinia virus immunization plays in the prevention and control of laboratory-acquired infections, and finally proposes solutions and countermeasures to further promote and implement immune control strategies. The problem related to immune strategy and laboratory- acquired infections which is being raised, analyzed and explored plays an active and instructive role in vaccinia virus related researches and laboratory- acquired infections, and also helps to recommend and develop relevant immune strategy for future vaccine control of such infections.展开更多
Selective Catalyst Reduction(SCR)Urea Dosing System(UDS)directly affects the system accuracy and the dynamic response performance of a vehicle.However,the UDS dynamic response is hard to keep up with the changes o...Selective Catalyst Reduction(SCR)Urea Dosing System(UDS)directly affects the system accuracy and the dynamic response performance of a vehicle.However,the UDS dynamic response is hard to keep up with the changes of the engine's operating conditions.That will lead to low NO_χconversion efficiency or NH_3 slip.In order to optimize the injection accuracy and the response speed of the UDS in dynamic conditions,an advanced control strategy based on an air-assisted volumetric UDS is presented.It covers the methods of flow compensation and switching working conditions.The strategy is authenticated on an UDS and tested in different dynamic conditions.The result shows that the control strategy discussed results in higher dynamic accuracy and faster dynamic response speed of UDS.The inject deviation range is improved from being between-8%and 10%to-4%and 2%and became more stable than before,and the dynamic response time was shortened from 200 ms to 150 ms.The ETC cycle result shows that after using the new strategy the NH_3 emission is reduced by 60%,and the NO_χemission remains almost unchanged.The trade-off between NO_χconversion efficiency and NH_3 slip is mitigated.The studied flow compensation and switching working conditions can improve the dynamic performance of the UDS significantly and make the UDS dynamic response keep up with the changes of the engine's operating conditions quickly.展开更多
The pests, diseases and weeds in sugarcane areas of Lincang Nanhua Sugar Industry Co.,Ltd. were investigated at seedling stage, growth stage and maturity stage of sugarcane from 2012 to 2016. The occurrence and damag...The pests, diseases and weeds in sugarcane areas of Lincang Nanhua Sugar Industry Co.,Ltd. were investigated at seedling stage, growth stage and maturity stage of sugarcane from 2012 to 2016. The occurrence and damage of diseases, pests and weeds were analyzed, and the problems in prevention and control were discussed based on the local conditions of sugarcane production. The species, occurrence and damage characteristics of diseases, pests and weeds were ascertained, and the corresponding strategies and technical measures were proposed.展开更多
Sugarcane red rot caused by Colletotrichum falcatum Went. is an important epidemical fungal disease. The outbreak of large-scale epidemics would cause huge losses to sugarcane production. At present,the pesticide cont...Sugarcane red rot caused by Colletotrichum falcatum Went. is an important epidemical fungal disease. The outbreak of large-scale epidemics would cause huge losses to sugarcane production. At present,the pesticide control effect is not ideal. Moreover,due to long-term continuous cropping and changeable climate in recent years,favorable conditions for the occurrence of red rot have been created. The disease was often prevalent in various sugarcane areas,caused serious damage and seriously affected the sugarcane production. With the rapid spread of the disease worldwide,the control of sugarcane red rot has become the hot spot in the field of sugarcane production and research. In this paper,the epidemic characteristics of sugarcane red rot were analyzed in combination with the field investigation. To provide theoretical basis for prevention and control of red rot in China and effective control the widespread occurrence of the disease,combined with the latest research results at home and abroad,we proposed to select resistant varieties mainly,use biological control agents such as Trichoderma spp.,Pseudomonas spp.and Bacillus spp. to treat the seed cane and soil,timely apply chemical pesticide in critical periods and strengthen scientific and effective comprehensive coordinated prevention and control measures such as field management against red rot.展开更多
In recent years,the conditions of continuous warm winter,more rain and high humidity are very beneficial to the breeding and survival of sugarcane diseases and pests.Coupled with the degradation of single varieties,mo...In recent years,the conditions of continuous warm winter,more rain and high humidity are very beneficial to the breeding and survival of sugarcane diseases and pests.Coupled with the degradation of single varieties,more attention on new plants and less on ratoon cane and the unscientific and unreasonable use of chemical pesticides,the types of sugarcane diseases and pests in the Menglian sugarcane area are increasing day by day,and the damage is increasing year by year,resulting in a substantial reduction in production and sugar,and a serious disaster threat to sugarcane production.Based on the field survey and the current sugarcane production practice in Menglian,this paper systematically reviewed the occurrence and damage dynamics and outbreak reasons of catastrophic diseases and pests that seriously influence sugarcane production,and proposed corresponding prevention and control strategies and integrated prevention and control technology according to the occurrence and damage characteristics of catastrophic diseases and pests.展开更多
The electromagnetic mass damper (EMD) control system, as an innovative active control system to reduce structural vibration, offers many advantages over traditional active mass driver/damper (AMD) control systems....The electromagnetic mass damper (EMD) control system, as an innovative active control system to reduce structural vibration, offers many advantages over traditional active mass driver/damper (AMD) control systems. In this paper, studies of several EMD control strategies and bench-scale shaking table tests of a two-story model structure are described. First, two structural models corresponding to uncontrolled and Zeroed cases are developed, and parameters of these models are validated through sinusoidal sweep tests to provide a basis for establishing an accurate mathematical model for further studies. Then, a simplified control strategy for the EMD system based on the pole assignment control algorithm is proposed. Moreover, ideal pole locations are derived and validated through a series of shaking table tests. Finally, three benchmark earthquake ground motions and sinusoidal sweep waves are imposed onto the structure to investigate the effectiveness and feasibility of using this type of innovative active control system for structural vibration control. In addition, the robustness of the EMD system is examined. The test results show that the EMD system is an effective and robust system for the control of structural vibrations.展开更多
With most countries paying attention to the environment protection, hybrid electric vehicles have become a focus of automobile research and development due to the characteristics of energy saving and low emission. Pow...With most countries paying attention to the environment protection, hybrid electric vehicles have become a focus of automobile research and development due to the characteristics of energy saving and low emission. Power follower control strategy(PFCS) and DC-link voltage control strategy are two sorts of control strategies for series hybrid electric vehicles(HEVs). Combining those two control strategies is a new idea for control strategy of series hybrid electric vehicles. By tuning essential parameters which are the defined constants under DClink voltage control and under PFCS, the points of minimum mass of equivalent fuel consumption(EFC) corresponding to a series of variables are marked for worldwide harmonized light vehicles test procedure(WLTP). The fuel economy of series HEVs with the combination control schemes performs better compared with individual control scheme. The results show the effects of the combination control schemes for series HEVs driving in an urban environment.展开更多
The structure and kinds of the fuel cell vehicle (FCV) and the mathematical model of the fuel cell processor are discussed in detail. FCV includes many parts: the fuel cell thermal and water management, fuel supply, a...The structure and kinds of the fuel cell vehicle (FCV) and the mathematical model of the fuel cell processor are discussed in detail. FCV includes many parts: the fuel cell thermal and water management, fuel supply, air supply and distribution, AC motor drive, main and auxiliary power management, and overall vehicle control system. So it requires different kinds of control strategies, such as the PID method, zero-pole method, optimal control method, fuzzy control and neural network control. Along with the progress of control method, the fuel cell vehicle's stability and reliability is up-and-up. Experiment results show FCV has high energy efficiency.展开更多
The main diseases and pests in the major growing area of jujube in Shanxi Province in recent years are investigated and studied,and several main diseases and pests are described.Based on the green prevention and contr...The main diseases and pests in the major growing area of jujube in Shanxi Province in recent years are investigated and studied,and several main diseases and pests are described.Based on the green prevention and control concept of crop diseases and pests proposed by the Ministry of Agriculture of China,the prevention and control of jujube diseases and pests are expounded from the perspectives of strengthening forecast,agricultural management,biological control and chemical control,in order to provide scientific basis for green development of jujube industry.展开更多
This paper reviews the various control algorithms and strategies used for fixed-wing morphing aircraft applications. It is evident from the literature that the development of control algorithms for morphing aircraft t...This paper reviews the various control algorithms and strategies used for fixed-wing morphing aircraft applications. It is evident from the literature that the development of control algorithms for morphing aircraft technologies focused on three main areas. The first area is related to precise control of the shape of morphing concepts for various flight conditions. The second area is mainly related to the flight dynamics, stability, and control aspects of morphing aircraft. The third area deals mainly with aeroelastic control using morphing concepts either for load alleviation purposes and/or to control the instability boundaries. The design of controllers for morphing aircraft/wings is very challenging due to the large changes that can occur in the structural, aerodynamic, and inertial characteristics. In addition, the type of actuation system and actuation rate/speed can have a significant effect on the design of such controllers. The aerospace community is in strong need of such a critical review especially as morphing aircraft technologies move from fundamental research at a low Technology Readiness Level(TRL) to real-life applications. This critical review aims to identify research gaps and propose future directions. In this paper, research activities/papers are categorized according to the control strategy used. This ranges from simple Proportional Integral Derivative(PID) controllers at one end to complex robust adaptive controllers and deep learning algorithms at the other end. This includes analytical, computational, and experimental studies. In addition, the various dynamic models used and their fidelities are highlighted and discussed.展开更多
This study combined the real-time monitoring and investigation of traffic flows to comprehensively analyze the road traffic flow and vehicle structure in downtown Beijing.A dynamic emission inventory of motor vehicle ...This study combined the real-time monitoring and investigation of traffic flows to comprehensively analyze the road traffic flow and vehicle structure in downtown Beijing.A dynamic emission inventory of motor vehicle air pollutants in downtown Beijing in 2021 was established,and the impact of these emissions on air quality was simulated and quantified,and different emission reduction control scenarios were proposed to evaluate their environmental improvement effects and explore measures to mitigate the impact of pollution emissions.The results show that the high traffic flow and the structure of the motor vehicle emissions in downtown Beijing are the main causes of severe motor vehicle pollution.Monitoring data shows that traffic flow in central Beijing is dominated by small passenger vehicles,while the vehicle mix is better than in other regions,with 72.0%of vehicles meeting"National V"or higher emission standards.However,to achieve higher air quality goals,further reducing vehicle emissions is necessary.Based on dynamic traffic flow,the average daily emissions of nitrogen oxides(NOX),particulate matters(PM_(2.5))and volatile organic compounds(VOC)from motor vehicles in central Beijing are 17.7 tons,0.6 tons and 14.0 tons,respectively,accounting for 23.0%of the city’s average daily motor vehicle emissions.If a zero-emission zone for motor vehicles were implemented in central Beijing,the annual average emission level of pollutants will be reduced by 10.4%to 21.0%.The designation of ultra-low emission zones for motor vehicles could be effective in improving the air quality in the center of Beijing.展开更多
Recent technological advancements have propelled remarkable progress in servo systems,resulting in their extensive utilization across various high-end applications.A comprehensive review of high-quality servo system t...Recent technological advancements have propelled remarkable progress in servo systems,resulting in their extensive utilization across various high-end applications.A comprehensive review of high-quality servo system technologies,focusing specifically on electrical motor topologies and control strategies is presented.In terms of motor topology,this study outlines the mainstream servo motors used across different periods,as well as the latest theories and technologies surrounding contemporary servo motors.In terms of control strategies,two well-established approaches are presented:field-oriented control and direct torque control.Additionally,it discusses advanced control strategies employed in servo systems,such as model predictive control(MPC)and fault tolerance control,among others.展开更多
Orthopoxviruses(OPXVs)belong to a group of nucleo-cytoplasmic large DNA viruses.Human pathogenic OPXVs(hpOPXVs)include at least five viruses,among which smallpox virus and monkeypox virus are the most dangerous viral ...Orthopoxviruses(OPXVs)belong to a group of nucleo-cytoplasmic large DNA viruses.Human pathogenic OPXVs(hpOPXVs)include at least five viruses,among which smallpox virus and monkeypox virus are the most dangerous viral pathogens.Both viruses are classified as category-one human infectious pathogens in China.Although smallpox was globally eradicated in the 1980 s,it is still a top biosecurity threat owing to the possibility of either being leaked to the outside world from a laboratory or being weaponized by terrorists.Beginning in early May 2022,a sudden outbreak of monkeypox was concurrently reported in more than 100 disparate geographical areas,representing a public health emergency of international concern,as declared by the World Health Organization(WHO).In this review,we present the reasons for hpOPXVs such as monkeypox virus presenting a potential threat to public health.We then systematically review the historical and recent development of vaccines and drugs against smallpox and monkeypox.In the final section,we highlight the importance of viromics studies as an integral part of a forward defense strategy to eliminate the potential threat to public health from emerging or re-emerging hpOPXVs and their variants.展开更多
High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping str...High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping strategies.This paper analyzes the influences of a feed-forward voltage filter and feedback current filter for the inner controller for the high-frequency impedance characteristics of the MMC based on a model.Moreover,the mechanism,influencing factors,and limitations of the existing strategy including an additional lowpass filter in the voltage feed-forward stage are investigated.Secondly,a resonance suppression strategy for the inclusion of additional cascaded notch filters in the voltage feed-forward stage is proposed,and its parameter design method and applicable scenarios are analyzed.In addition,this paper analyzes the effects of the inclusion of an additional control in other stages for the inner controller of the MMC.Finally,the correctness of the theoretical analysis and the proposed strategy is verified based on the simulation of an actual project on PSCAD/EMTDC.展开更多
This paper develops a novel hierarchical control strategy for improving the trajectory tracking capability of aerial robots under parameter uncertainties.The hierarchical control strategy is composed of an adaptive sl...This paper develops a novel hierarchical control strategy for improving the trajectory tracking capability of aerial robots under parameter uncertainties.The hierarchical control strategy is composed of an adaptive sliding mode controller and a model-free iterative sliding mode controller(MFISMC).A position controller is designed based on adaptive sliding mode control(SMC)to safely drive the aerial robot and ensure fast state convergence under external disturbances.Additionally,the MFISMC acts as an attitude controller to estimate the unmodeled dynamics without detailed knowledge of aerial robots.Then,the adaption laws are derived with the Lyapunov theory to guarantee the asymptotic tracking of the system state.Finally,to demonstrate the performance and robustness of the proposed control strategy,numerical simulations are carried out,which are also compared with other conventional strategies,such as proportional-integralderivative(PID),backstepping(BS),and SMC.The simulation results indicate that the proposed hierarchical control strategy can fulfill zero steady-state error and achieve faster convergence compared with conventional strategies.展开更多
Parking in a small parking lot within limited space poses a difficult task. It often leads to deviations between the final parking posture and the target posture. These deviations can lead to partial occupancy of adja...Parking in a small parking lot within limited space poses a difficult task. It often leads to deviations between the final parking posture and the target posture. These deviations can lead to partial occupancy of adjacent parking lots, which poses a safety threat to vehicles parked in these parking lots. However, previous studies have not addressed this issue. In this paper, we aim to evaluate the impact of parking deviation of existing vehicles next to the target parking lot(PDEVNTPL) on the automatic ego vehicle(AEV) parking, in terms of safety, comfort, accuracy, and efficiency of parking. A segmented parking training framework(SPTF) based on soft actor-critic(SAC) is proposed to improve parking performance. In the proposed method, the SAC algorithm incorporates strategy entropy into the objective function, to enable the AEV to learn parking strategies based on a more comprehensive understanding of the environment. Additionally, the SPTF simplifies complex parking tasks to maintain the high performance of deep reinforcement learning(DRL). The experimental results reveal that the PDEVNTPL has a detrimental influence on the AEV parking in terms of safety, accuracy, and comfort, leading to reductions of more than 27%, 54%, and 26%respectively. However, the SAC-based SPTF effectively mitigates this impact, resulting in a considerable increase in the parking success rate from 71% to 93%. Furthermore, the heading angle deviation is significantly reduced from 2.25 degrees to 0.43degrees.展开更多
This paper addresses the micro wind-hydrogen coupled system,aiming to improve the power tracking capability of micro wind farms,the regulation capability of hydrogen storage systems,and to mitigate the volatility of w...This paper addresses the micro wind-hydrogen coupled system,aiming to improve the power tracking capability of micro wind farms,the regulation capability of hydrogen storage systems,and to mitigate the volatility of wind power generation.A predictive control strategy for the micro wind-hydrogen coupled system is proposed based on the ultra-short-term wind power prediction,the hydrogen storage state division interval,and the daily scheduled output of wind power generation.The control strategy maximizes the power tracking capability,the regulation capability of the hydrogen storage system,and the fluctuation of the joint output of the wind-hydrogen coupled system as the objective functions,and adaptively optimizes the control coefficients of the hydrogen storage interval and the output parameters of the system by the combined sigmoid function and particle swarm algorithm(sigmoid-PSO).Compared with the real-time control strategy,the proposed predictive control strategy can significantly improve the output tracking capability of the wind-hydrogen coupling system,minimize the gap between the actual output and the predicted output,significantly enhance the regulation capability of the hydrogen storage system,and mitigate the power output fluctuation of the wind-hydrogen integrated system,which has a broad practical application prospect.展开更多
Residential air conditioning(RAC)loads have great potential to be included in demand response(DR)programs.This paper studies large-scale RAC loads participating in DR programs,such as modeling,parameters identificatio...Residential air conditioning(RAC)loads have great potential to be included in demand response(DR)programs.This paper studies large-scale RAC loads participating in DR programs,such as modeling,parameters identification,DR characteristics and control strategies.First,an aggregate model of large-scale RAC loads are established based on the buildings’performance with heat storage and insulation,avoiding the calculation of a single RAC model.Then,parameters of the aggregate model are identified based on the RACs’power and outdoor temperatures.Based on the aggregate model,DR characteristics of RAC loads are analyzed,including the dynamic relationship between power,outdoor and indoor temperature,and the potential of DR combined with the users’comfort.Next,the DR control strategies adapted for large-scale RAC loads are established by adjusting the temperature set-points.The DR strategies consider users’comfort and calculate the control signals of each RAC load according to the DR power,including adjustment temperature and adjustment time,which are sent to each RAC load for execution.In the DR process,the control center does not need to obtain the users’indoor temperature,which is conducive to protecting the users’privacy.DR strategies of RAC loads when the control degree within/beyond the DR potential are both proposed,and a load recovery control strategy is also introduced.Finally,the effectiveness and accuracy of the proposed model and DR control strategies are verified by simulation results.展开更多
文摘Objective: To evaluate the role of prevention and control strategies for nosocomial infection in a tertiary teaching hospital during the sudden outbreak of Corona Virus Disease 2019 (COVID-19). Methods: The hospital initiated an emergency plan involving multi-departmental defense and control. It adopted a series of nosocomial infection prevention and control measures, including strengthening pre-examination and triage, optimizing the consultation process, improving the hospital’s architectural composition, implementing graded risk management, enhancing personal protection, and implementing staff training and supervision. Descriptive research was used to evaluate the short-term effects of these in-hospital prevention and control strategies. The analysis compared changes in related evaluation indicators between January 24, 2020 and February 12, 2020 (Chinese Lunar New Year’s Eve 2020 to lunar January 19) and the corresponding lunar period of the previous year. Results: Compared to the same period last year, the outpatient fever rate increased by 1.85-fold (P P Conclusion: The nosocomial infection prevention and control strategies implemented during this specific period improved the detection and control abilities for the COVID-19 source of infection and enhanced the compliance with measures. This likely contributed significantly to avoiding the occurrence of nosocomial infection.
文摘Osteoporosis is a common bone disease in women worldwide, leading to decreased bone density and an accelerated risk of fractures. The causes of osteoporosis in women include age (senile osteoporosis), menopause-associated hormonal changes, deficiencies in calcium and vitamin D, genetics, lifestyle factors, medical conditions, and some type of medications. The consequences of osteoporosis are colossal, consisting of fractures, decreased quality of life, psychological impacts, and economic burden. To effectively control the menace of osteoporosis in women, numerous strategies are advocated. Adequate calcium and vitamin D consumption through diet or supplements is vital. Regular weight-bearing activities and strength training that promote bone density. Maintaining a healthy life-style through avoiding smoking, limiting alcohol in-take and maintaining a wholesome body weight is essential. Hormone replacement therapy and some medications may be recommended in certain cases. Early detection through regular bone density and blood tests is crucial to lowering its impact. Creating a supportive network through educational programs and resources fosters awareness and empowerment. By engaging these strategies, women can be empowered to combat osteoporosis, reduce fracture risk, and build stronger bones for their overall well-being.
基金supported by the National Health and Family Planning Commission(201302006)
文摘While presenting biological characteristics of vaccinia virus and laboratory-acquired infections during related research processes, this paper focuses on benefits and risks of vaccinia virus immunization in relation to laboratory-acquired infections, describes characteristics and the adaptation of vaccinia virus vaccine, analyses the role vaccinia virus immunization plays in the prevention and control of laboratory-acquired infections, and finally proposes solutions and countermeasures to further promote and implement immune control strategies. The problem related to immune strategy and laboratory- acquired infections which is being raised, analyzed and explored plays an active and instructive role in vaccinia virus related researches and laboratory- acquired infections, and also helps to recommend and develop relevant immune strategy for future vaccine control of such infections.
基金Supported by National Hi-tech Research and Development Program of China(863 Program,Grant No.2012AA111708)
文摘Selective Catalyst Reduction(SCR)Urea Dosing System(UDS)directly affects the system accuracy and the dynamic response performance of a vehicle.However,the UDS dynamic response is hard to keep up with the changes of the engine's operating conditions.That will lead to low NO_χconversion efficiency or NH_3 slip.In order to optimize the injection accuracy and the response speed of the UDS in dynamic conditions,an advanced control strategy based on an air-assisted volumetric UDS is presented.It covers the methods of flow compensation and switching working conditions.The strategy is authenticated on an UDS and tested in different dynamic conditions.The result shows that the control strategy discussed results in higher dynamic accuracy and faster dynamic response speed of UDS.The inject deviation range is improved from being between-8%and 10%to-4%and 2%and became more stable than before,and the dynamic response time was shortened from 200 ms to 150 ms.The ETC cycle result shows that after using the new strategy the NH_3 emission is reduced by 60%,and the NO_χemission remains almost unchanged.The trade-off between NO_χconversion efficiency and NH_3 slip is mitigated.The studied flow compensation and switching working conditions can improve the dynamic performance of the UDS significantly and make the UDS dynamic response keep up with the changes of the engine's operating conditions quickly.
基金Supported by Special Fund for China Agricultural Industry Research System(CARS-170303)Special Fund for Agricultural Industry Research System of Yunnan Province(YNGZTX-4-92)
文摘The pests, diseases and weeds in sugarcane areas of Lincang Nanhua Sugar Industry Co.,Ltd. were investigated at seedling stage, growth stage and maturity stage of sugarcane from 2012 to 2016. The occurrence and damage of diseases, pests and weeds were analyzed, and the problems in prevention and control were discussed based on the local conditions of sugarcane production. The species, occurrence and damage characteristics of diseases, pests and weeds were ascertained, and the corresponding strategies and technical measures were proposed.
基金Supported by Sugar Crop Research System (CARS-170303)the Yunling Industry and Technology Leading Talent Training Program "Prevention and Control of Sugarcane Pests"(2018LJRC56)the Yunnan Province Agriculture Research System (YNGZTX-4-92)。
文摘Sugarcane red rot caused by Colletotrichum falcatum Went. is an important epidemical fungal disease. The outbreak of large-scale epidemics would cause huge losses to sugarcane production. At present,the pesticide control effect is not ideal. Moreover,due to long-term continuous cropping and changeable climate in recent years,favorable conditions for the occurrence of red rot have been created. The disease was often prevalent in various sugarcane areas,caused serious damage and seriously affected the sugarcane production. With the rapid spread of the disease worldwide,the control of sugarcane red rot has become the hot spot in the field of sugarcane production and research. In this paper,the epidemic characteristics of sugarcane red rot were analyzed in combination with the field investigation. To provide theoretical basis for prevention and control of red rot in China and effective control the widespread occurrence of the disease,combined with the latest research results at home and abroad,we proposed to select resistant varieties mainly,use biological control agents such as Trichoderma spp.,Pseudomonas spp.and Bacillus spp. to treat the seed cane and soil,timely apply chemical pesticide in critical periods and strengthen scientific and effective comprehensive coordinated prevention and control measures such as field management against red rot.
基金Supported by Sugar Crop Research System(CARS-170303)the Yunling Industry and Technology Leading Talent Training Program(2018LJRC56)+1 种基金Menglian and Changyu Science and Enterprise Cooperation Projectthe Yunnan Province Agriculture Research System.
文摘In recent years,the conditions of continuous warm winter,more rain and high humidity are very beneficial to the breeding and survival of sugarcane diseases and pests.Coupled with the degradation of single varieties,more attention on new plants and less on ratoon cane and the unscientific and unreasonable use of chemical pesticides,the types of sugarcane diseases and pests in the Menglian sugarcane area are increasing day by day,and the damage is increasing year by year,resulting in a substantial reduction in production and sugar,and a serious disaster threat to sugarcane production.Based on the field survey and the current sugarcane production practice in Menglian,this paper systematically reviewed the occurrence and damage dynamics and outbreak reasons of catastrophic diseases and pests that seriously influence sugarcane production,and proposed corresponding prevention and control strategies and integrated prevention and control technology according to the occurrence and damage characteristics of catastrophic diseases and pests.
基金The National Natural Science Foundation of China Under Grant. No.50608026The National Major Foundamental Program (973 Program) of China Under Grant No. 2007CB714204
文摘The electromagnetic mass damper (EMD) control system, as an innovative active control system to reduce structural vibration, offers many advantages over traditional active mass driver/damper (AMD) control systems. In this paper, studies of several EMD control strategies and bench-scale shaking table tests of a two-story model structure are described. First, two structural models corresponding to uncontrolled and Zeroed cases are developed, and parameters of these models are validated through sinusoidal sweep tests to provide a basis for establishing an accurate mathematical model for further studies. Then, a simplified control strategy for the EMD system based on the pole assignment control algorithm is proposed. Moreover, ideal pole locations are derived and validated through a series of shaking table tests. Finally, three benchmark earthquake ground motions and sinusoidal sweep waves are imposed onto the structure to investigate the effectiveness and feasibility of using this type of innovative active control system for structural vibration control. In addition, the robustness of the EMD system is examined. The test results show that the EMD system is an effective and robust system for the control of structural vibrations.
基金supported in part by the National Natural Science Foundation of China(61773382,61773381,61533019)Chinese Guangdongs S&T projects(2016B090910001,2017B090912001)+1 种基金2016 S&T Benefiting Special Project(16-6-2-62-nsh)of Qingdao Achievements Transformation ProgramDongguan Innovation Talents Project(Gang Xiong)
文摘With most countries paying attention to the environment protection, hybrid electric vehicles have become a focus of automobile research and development due to the characteristics of energy saving and low emission. Power follower control strategy(PFCS) and DC-link voltage control strategy are two sorts of control strategies for series hybrid electric vehicles(HEVs). Combining those two control strategies is a new idea for control strategy of series hybrid electric vehicles. By tuning essential parameters which are the defined constants under DClink voltage control and under PFCS, the points of minimum mass of equivalent fuel consumption(EFC) corresponding to a series of variables are marked for worldwide harmonized light vehicles test procedure(WLTP). The fuel economy of series HEVs with the combination control schemes performs better compared with individual control scheme. The results show the effects of the combination control schemes for series HEVs driving in an urban environment.
文摘The structure and kinds of the fuel cell vehicle (FCV) and the mathematical model of the fuel cell processor are discussed in detail. FCV includes many parts: the fuel cell thermal and water management, fuel supply, air supply and distribution, AC motor drive, main and auxiliary power management, and overall vehicle control system. So it requires different kinds of control strategies, such as the PID method, zero-pole method, optimal control method, fuzzy control and neural network control. Along with the progress of control method, the fuel cell vehicle's stability and reliability is up-and-up. Experiment results show FCV has high energy efficiency.
基金Sponsored by Young and Middle-aged Innovative Talents Training Program of Universities and Colleges in Tianjin (J01009030709)Enterprise Science and Technology Commissioner Project of Tianjin (20YDTPJC01330)+1 种基金Agricultural Science and Technology Project of Baodi District (201918)Cultivation Project of Hetian Polytechnic Horizontal Joint Project of Yisheng Orchard in Hetian City。
文摘The main diseases and pests in the major growing area of jujube in Shanxi Province in recent years are investigated and studied,and several main diseases and pests are described.Based on the green prevention and control concept of crop diseases and pests proposed by the Ministry of Agriculture of China,the prevention and control of jujube diseases and pests are expounded from the perspectives of strengthening forecast,agricultural management,biological control and chemical control,in order to provide scientific basis for green development of jujube industry.
基金funded by Abu Dhabi Education Council Award for Research Excellence Program (AARE 2019) _(No. AARE19-213)by Khalifa University of Science and Technology through Faculty Start-up Award (No. FSU-2020-20)。
文摘This paper reviews the various control algorithms and strategies used for fixed-wing morphing aircraft applications. It is evident from the literature that the development of control algorithms for morphing aircraft technologies focused on three main areas. The first area is related to precise control of the shape of morphing concepts for various flight conditions. The second area is mainly related to the flight dynamics, stability, and control aspects of morphing aircraft. The third area deals mainly with aeroelastic control using morphing concepts either for load alleviation purposes and/or to control the instability boundaries. The design of controllers for morphing aircraft/wings is very challenging due to the large changes that can occur in the structural, aerodynamic, and inertial characteristics. In addition, the type of actuation system and actuation rate/speed can have a significant effect on the design of such controllers. The aerospace community is in strong need of such a critical review especially as morphing aircraft technologies move from fundamental research at a low Technology Readiness Level(TRL) to real-life applications. This critical review aims to identify research gaps and propose future directions. In this paper, research activities/papers are categorized according to the control strategy used. This ranges from simple Proportional Integral Derivative(PID) controllers at one end to complex robust adaptive controllers and deep learning algorithms at the other end. This includes analytical, computational, and experimental studies. In addition, the various dynamic models used and their fidelities are highlighted and discussed.
基金supported by the National Key Research and Development Program of China (No.2022YFC3800403)the Foundation of Beijing Municipal Research Institute of EcoEnvironmental Protection (No.Y2022-007)。
文摘This study combined the real-time monitoring and investigation of traffic flows to comprehensively analyze the road traffic flow and vehicle structure in downtown Beijing.A dynamic emission inventory of motor vehicle air pollutants in downtown Beijing in 2021 was established,and the impact of these emissions on air quality was simulated and quantified,and different emission reduction control scenarios were proposed to evaluate their environmental improvement effects and explore measures to mitigate the impact of pollution emissions.The results show that the high traffic flow and the structure of the motor vehicle emissions in downtown Beijing are the main causes of severe motor vehicle pollution.Monitoring data shows that traffic flow in central Beijing is dominated by small passenger vehicles,while the vehicle mix is better than in other regions,with 72.0%of vehicles meeting"National V"or higher emission standards.However,to achieve higher air quality goals,further reducing vehicle emissions is necessary.Based on dynamic traffic flow,the average daily emissions of nitrogen oxides(NOX),particulate matters(PM_(2.5))and volatile organic compounds(VOC)from motor vehicles in central Beijing are 17.7 tons,0.6 tons and 14.0 tons,respectively,accounting for 23.0%of the city’s average daily motor vehicle emissions.If a zero-emission zone for motor vehicles were implemented in central Beijing,the annual average emission level of pollutants will be reduced by 10.4%to 21.0%.The designation of ultra-low emission zones for motor vehicles could be effective in improving the air quality in the center of Beijing.
基金Supported by the National Natural Science Foundation of China under Major Project 51991380.
文摘Recent technological advancements have propelled remarkable progress in servo systems,resulting in their extensive utilization across various high-end applications.A comprehensive review of high-quality servo system technologies,focusing specifically on electrical motor topologies and control strategies is presented.In terms of motor topology,this study outlines the mainstream servo motors used across different periods,as well as the latest theories and technologies surrounding contemporary servo motors.In terms of control strategies,two well-established approaches are presented:field-oriented control and direct torque control.Additionally,it discusses advanced control strategies employed in servo systems,such as model predictive control(MPC)and fault tolerance control,among others.
基金This work was supported by the National Science and Technology Major Project of China(2018ZX10711001-006).
文摘Orthopoxviruses(OPXVs)belong to a group of nucleo-cytoplasmic large DNA viruses.Human pathogenic OPXVs(hpOPXVs)include at least five viruses,among which smallpox virus and monkeypox virus are the most dangerous viral pathogens.Both viruses are classified as category-one human infectious pathogens in China.Although smallpox was globally eradicated in the 1980 s,it is still a top biosecurity threat owing to the possibility of either being leaked to the outside world from a laboratory or being weaponized by terrorists.Beginning in early May 2022,a sudden outbreak of monkeypox was concurrently reported in more than 100 disparate geographical areas,representing a public health emergency of international concern,as declared by the World Health Organization(WHO).In this review,we present the reasons for hpOPXVs such as monkeypox virus presenting a potential threat to public health.We then systematically review the historical and recent development of vaccines and drugs against smallpox and monkeypox.In the final section,we highlight the importance of viromics studies as an integral part of a forward defense strategy to eliminate the potential threat to public health from emerging or re-emerging hpOPXVs and their variants.
基金supported in part by Science and Technology Project of State Grid Corporation of China,“Research on Harmonic Oscillation ProblemsSuppression Strategies of Flexible DC Connected to AC Grid”,(No.SGTYHT/17-JS-199).
文摘High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping strategies.This paper analyzes the influences of a feed-forward voltage filter and feedback current filter for the inner controller for the high-frequency impedance characteristics of the MMC based on a model.Moreover,the mechanism,influencing factors,and limitations of the existing strategy including an additional lowpass filter in the voltage feed-forward stage are investigated.Secondly,a resonance suppression strategy for the inclusion of additional cascaded notch filters in the voltage feed-forward stage is proposed,and its parameter design method and applicable scenarios are analyzed.In addition,this paper analyzes the effects of the inclusion of an additional control in other stages for the inner controller of the MMC.Finally,the correctness of the theoretical analysis and the proposed strategy is verified based on the simulation of an actual project on PSCAD/EMTDC.
文摘This paper develops a novel hierarchical control strategy for improving the trajectory tracking capability of aerial robots under parameter uncertainties.The hierarchical control strategy is composed of an adaptive sliding mode controller and a model-free iterative sliding mode controller(MFISMC).A position controller is designed based on adaptive sliding mode control(SMC)to safely drive the aerial robot and ensure fast state convergence under external disturbances.Additionally,the MFISMC acts as an attitude controller to estimate the unmodeled dynamics without detailed knowledge of aerial robots.Then,the adaption laws are derived with the Lyapunov theory to guarantee the asymptotic tracking of the system state.Finally,to demonstrate the performance and robustness of the proposed control strategy,numerical simulations are carried out,which are also compared with other conventional strategies,such as proportional-integralderivative(PID),backstepping(BS),and SMC.The simulation results indicate that the proposed hierarchical control strategy can fulfill zero steady-state error and achieve faster convergence compared with conventional strategies.
基金supported by National Natural Science Foundation of China(52222215, 52272420, 52072051)。
文摘Parking in a small parking lot within limited space poses a difficult task. It often leads to deviations between the final parking posture and the target posture. These deviations can lead to partial occupancy of adjacent parking lots, which poses a safety threat to vehicles parked in these parking lots. However, previous studies have not addressed this issue. In this paper, we aim to evaluate the impact of parking deviation of existing vehicles next to the target parking lot(PDEVNTPL) on the automatic ego vehicle(AEV) parking, in terms of safety, comfort, accuracy, and efficiency of parking. A segmented parking training framework(SPTF) based on soft actor-critic(SAC) is proposed to improve parking performance. In the proposed method, the SAC algorithm incorporates strategy entropy into the objective function, to enable the AEV to learn parking strategies based on a more comprehensive understanding of the environment. Additionally, the SPTF simplifies complex parking tasks to maintain the high performance of deep reinforcement learning(DRL). The experimental results reveal that the PDEVNTPL has a detrimental influence on the AEV parking in terms of safety, accuracy, and comfort, leading to reductions of more than 27%, 54%, and 26%respectively. However, the SAC-based SPTF effectively mitigates this impact, resulting in a considerable increase in the parking success rate from 71% to 93%. Furthermore, the heading angle deviation is significantly reduced from 2.25 degrees to 0.43degrees.
基金the Key Research&Development Program of Xinjiang(Grant Number 2022B01003).
文摘This paper addresses the micro wind-hydrogen coupled system,aiming to improve the power tracking capability of micro wind farms,the regulation capability of hydrogen storage systems,and to mitigate the volatility of wind power generation.A predictive control strategy for the micro wind-hydrogen coupled system is proposed based on the ultra-short-term wind power prediction,the hydrogen storage state division interval,and the daily scheduled output of wind power generation.The control strategy maximizes the power tracking capability,the regulation capability of the hydrogen storage system,and the fluctuation of the joint output of the wind-hydrogen coupled system as the objective functions,and adaptively optimizes the control coefficients of the hydrogen storage interval and the output parameters of the system by the combined sigmoid function and particle swarm algorithm(sigmoid-PSO).Compared with the real-time control strategy,the proposed predictive control strategy can significantly improve the output tracking capability of the wind-hydrogen coupling system,minimize the gap between the actual output and the predicted output,significantly enhance the regulation capability of the hydrogen storage system,and mitigate the power output fluctuation of the wind-hydrogen integrated system,which has a broad practical application prospect.
基金supported by the Major State Basic Research Development Program of China under Grant No.2016YFB0901100the National Science Foundation of China under Grant No.51577051the Science and Technology Project of SGCC“Research on the system for friendly supply-demand interaction between urban electric power customers and power grid”.
文摘Residential air conditioning(RAC)loads have great potential to be included in demand response(DR)programs.This paper studies large-scale RAC loads participating in DR programs,such as modeling,parameters identification,DR characteristics and control strategies.First,an aggregate model of large-scale RAC loads are established based on the buildings’performance with heat storage and insulation,avoiding the calculation of a single RAC model.Then,parameters of the aggregate model are identified based on the RACs’power and outdoor temperatures.Based on the aggregate model,DR characteristics of RAC loads are analyzed,including the dynamic relationship between power,outdoor and indoor temperature,and the potential of DR combined with the users’comfort.Next,the DR control strategies adapted for large-scale RAC loads are established by adjusting the temperature set-points.The DR strategies consider users’comfort and calculate the control signals of each RAC load according to the DR power,including adjustment temperature and adjustment time,which are sent to each RAC load for execution.In the DR process,the control center does not need to obtain the users’indoor temperature,which is conducive to protecting the users’privacy.DR strategies of RAC loads when the control degree within/beyond the DR potential are both proposed,and a load recovery control strategy is also introduced.Finally,the effectiveness and accuracy of the proposed model and DR control strategies are verified by simulation results.