In order to enhance the yield and quality of cashew,it is essential to implement high-yield cultivation techniques effectively throughout the production process.Additionally,pest control measures should be employed to...In order to enhance the yield and quality of cashew,it is essential to implement high-yield cultivation techniques effectively throughout the production process.Additionally,pest control measures should be employed to provide technical support for the industrialized development of cashew.展开更多
The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous...The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control results.This article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its effectiveness.The overview encompassed several key elements,delving into anchoring theory and grouting reinforcement theory.The new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also highlighted.The discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole pressure.An examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was conducted.Additionally,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting reinforcement.Furthermore,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable bolts.The application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was introduced.Finally,the existing problems in grouted bolting control technology for deep soft rock roadways are analyzed,and the future development trend of grouted bolting control technology is anticipated.展开更多
Automatic control technology is the basis of road robot improvement,according to the characteristics of construction equipment and functions,the research will be input type perception from positioning acquisition,real...Automatic control technology is the basis of road robot improvement,according to the characteristics of construction equipment and functions,the research will be input type perception from positioning acquisition,real-world monitoring,the process will use RTK-GNSS positional perception technology,by projecting the left side of the earth from Gauss-Krueger projection method,and then carry out the Cartesian conversion based on the characteristics of drawing;steering control system is the core of the electric drive unmanned module,on the basis of the analysis of the composition of the steering system of unmanned engineering vehicles,the steering system key components such as direction,torque sensor,drive motor and other models are established,the joint simulation model of unmanned engineering vehicles is established,the steering controller is designed using the PID method,the simulation results show that the control method can meet the construction path demand for automatic steering.The path planning will first formulate the construction area with preset values and realize the steering angle correction during driving by PID algorithm,and never realize the construction-based path planning,and the results show that the method can control the straight path within the error of 10 cm and the curve error within 20 cm.With the collaboration of various modules,the automatic construction simulation results of this robot show that the design path and control method is effective.展开更多
The article mainly studies the application strategy of automatic addressable single-lamp control technology in tunnel lighting.It encompasses an introduction to this technology,an analysis of the tunnel lighting syste...The article mainly studies the application strategy of automatic addressable single-lamp control technology in tunnel lighting.It encompasses an introduction to this technology,an analysis of the tunnel lighting system using automatic addressable single-lamp control technology,and outlines the main development direction for this technology in modern tunnel lighting.The aim is to offer insights that can inform the rational deployment of this technology,thereby enhancing the lighting control effectiveness in modern tunnels and meeting their specific lighting requirements more effectively.展开更多
China's infrastructure has gradually achieved large-scale development,and transportation construction has also shifted from east to west,transitioning from plains to mountainous areas.High-fill embankments of diff...China's infrastructure has gradually achieved large-scale development,and transportation construction has also shifted from east to west,transitioning from plains to mountainous areas.High-fill embankments of different sizes in mountainous areas are unavoidable,and the settlement of high-fill embankments is usually the most concerned issue in high-fill projects.According to the current research of highway projects,most of the high embankments in mountainous areas are soil-rock mixed embankments or rock-filled embankments,and their post-construction settlements are directly related to construction technology and the type of filler used.In this paper,the problems in the settlement control of earth-filled embankment and related factors are analyzed in detail.The settlement control technology of high-fill embankment in high-cold and high-altitude areas is also discussed,so as to ensure the overall quality of high-fill embankment.展开更多
On the basis of the theory of continuous compaction technology, we put forward the vibratory compaction value (VCV) index measured by a roller compactor, in order to evaluate the quality of continuously compacted su...On the basis of the theory of continuous compaction technology, we put forward the vibratory compaction value (VCV) index measured by a roller compactor, in order to evaluate the quality of continuously compacted subgrade. The relationships between the VCV index and the currently used indexes K30, Evd, Ev1 and Ev2, were explored by analyzing the experimental data collected from two test sections on the Beijing - Shanghai High-Speed Railway. The result shows that the VCV index has a linear relationship with the currently used indexes.展开更多
Aiming at the characteristics of modularity and reconfigurable in open architecture computer numerical control (CNC) system, the open architecture CNC system, Harbin Institute of Tech- nology computer numerical cont...Aiming at the characteristics of modularity and reconfigurable in open architecture computer numerical control (CNC) system, the open architecture CNC system, Harbin Institute of Tech- nology computer numerical control (HITCNC), is researched and manufactured based on the interface standards. The system's external interfaces are coincident with the corresponding international standards, and the internal interfaces follow the open modular architecture controller (OMAC) agreement. In the research and manufacturing process, object-oriented technology is used to ensure the openness of the HITCNC, and static programming is applied in the CNC system according to the idea of modularization disassembly. The HITCNC also actualizes real-time and unreal-time modules adopting real-time dynamical linked library (RTDLL) and component object model (COM). Finite state ma- chine (FSM) is adopted to do dynamically modeling of HITCNC. The complete separation between the software and the hardware is achieved in the HITCNC by applying the SoftSERCANS technique. The application of the above key techniques decreases the programming workload greatly, and uses software programs replacing hardware functions, which offers plenty technique ensures for the openness of HITCNC. Finally, based on the HITCNC, a three-dimensional milling system is established. On the system, series experiments are done to validate the expandability and interchangeability of HITCNC. The results of the experiments show that the established open architecture CNC system HITCNC is correct and feasible, and has good openness.展开更多
To ameliorate the defects of insufcient support resistance of traditional roadside flling bodies for gob-side entry retaining(GER),overcome the inability to adapt to the deformation of surrounding rock,and isolate the...To ameliorate the defects of insufcient support resistance of traditional roadside flling bodies for gob-side entry retaining(GER),overcome the inability to adapt to the deformation of surrounding rock,and isolate the goaf efectively,a new type of high-water material as a roadside flling body for GER technology with double roadways was proposed.The instability analysis and control technology of GER with double roadways by flling high-water material into a gently inclined coal seam were studied.The basic mechanical properties of the new high-water material were investigated through laboratory experiments,and their main advantages were identifed.The reasonable width of the roadside flling wall of a high-water material was obtained by combining ground pressure observation and theoretical calculations.The distribution characteristics of the stress and plastic zone of surrounding rock of GER after being stabilized by the disturbance of the working face were studied using numerical simulations,and the failure range of GER by flling with high-water material was revealed.Based on this,a coupling control technology of anchor cables and bolts+single props+metal mesh+anchor bolts is proposed.Through the coupling methods of arranging borehole peeping and observing the convergences of surrounding rock,the results demonstrate that GER with double roadways by flling with a 1.8-m-wide high-water material has a good control efect.The above research will play an active role in promoting the application of high-water materials in GER roadside flling.展开更多
Electrical system of military vehicle is a typical parameterized nonlinear system where complicated bifurcations may exist and threaten its safe and stable operation. An algebraic criterion for Hopf bifurcation is pre...Electrical system of military vehicle is a typical parameterized nonlinear system where complicated bifurcations may exist and threaten its safe and stable operation. An algebraic criterion for Hopf bifurcation is presented briefly and applied to find Hopf bifurcation point of the electrical system with automatic voltage regulator(AVR) dynamics in military vehicle. Hopf bifurcation controllers are designed for this electrical system by using wash-out filter,linear feedback,nonlinear feedback and their combination. The linear feedback control makes the system bring Hopf bifurcation at preferable parameter,the nonlinear feedback control modifies the type of the bifurcation,and the wash-out filter enhances the system damping,thus,the Hopf bifurcation is eliminated and the electrical system stability is ensured. Simulation results show the controller's validity.展开更多
After systematic monitoring and field survey in orchard for three years from 2009 to 2011, it was found that Bactrocera dorsalis occurred for more than three generations each year on the north shore of the middle and ...After systematic monitoring and field survey in orchard for three years from 2009 to 2011, it was found that Bactrocera dorsalis occurred for more than three generations each year on the north shore of the middle and lower reaches of Yangtze River, with overlapping generations; the activity peak of adults was from mid August to late September; the occurrence in citrus orchard in hilly and mountainous area was severe; the average insect-fruit rate in October reached 0.20% - 15.88% ; B. dorsalis had sporadic occurrence in other orchards. The integrated control measures of plowing in winter to kill pupae, removing insect-fruits, boycott- ing on the ground, trapping by sex attraetants and spraying pesticides could basically control the damage of B. dorsalis.展开更多
Kiwifruit root rot is an important root disease of kiwifruit, which has occurred increasingly in recent years. The disease leads to the death of whole kiwifruit plant under severe condition, and has become an importan...Kiwifruit root rot is an important root disease of kiwifruit, which has occurred increasingly in recent years. The disease leads to the death of whole kiwifruit plant under severe condition, and has become an important disease restricting kiwi fruit industry development. The characteris-tics, occurrence, etiology and symptoms of kiwifruit root rot were introduced in the paper, and the prevention and control technology against the dis-ease were put forward from the aspects of agriculture, biology and chemistry.展开更多
Surface roughness considerably influences the stamping and coating performance of the automotive plates;however,the surface roughness of the automotive plates is transferred from the roll during the rolling process.Th...Surface roughness considerably influences the stamping and coating performance of the automotive plates;however,the surface roughness of the automotive plates is transferred from the roll during the rolling process.Therefore,the variation and control technology regarding the roughness of the automotive plates and rolls has drawn increasing attention from researchers in China and around the globe.In this study,the research methods,analytical techniques,prediction models,transfer rules,and control technologies regarding the surface roughness of the automotive plates and rolls were reviewed.Among these,an online measurement system for automotive-plate and roll surface roughness has been applied to the production lines of Germany,China,Belgium,Holland,Austria,and other countries and has achieved remarkable results.Online measurement and timely feedback regarding the automotive-plate and roll surface roughness are needed to ensure favorable conditions for the establishment of automotive-plate roughness-control measurement.展开更多
In order to actively develop green ecological strawberry, the authors have studied integrated microecological prevention and control technologies of strawberry continuous cropping diseases, including increasing soil b...In order to actively develop green ecological strawberry, the authors have studied integrated microecological prevention and control technologies of strawberry continuous cropping diseases, including increasing soil biomass and solar high temperature disinfection during strawberry greenhouse leisure period in summer, biological fertilizer (agent) treatment before colonization, root irrigation treatment with biocontrol agent, as well as appropriate amount of fulvic acid and cytex after colonization, forming a supporting technical system for the microecological prevention and control of soil-borne diseases in facilities. The demonstration application in production shows that the technology has the functions of restoring and enhancing soil biological fertility, enriching beneficial microbial flora, antagonizing harmful bacteria, significantly promoting the growth and development of strawberry, reducing the incidence of soil-borne diseases, reducing the use of chemical fertilizers and pesticides, promoting the early ripening and high yield of strawberry, significantly improving the quality and flavor of strawberry, reducing the risk of pesticide residues, and boosting consumer confidence, which further improves the economic benefit, social benefit and ecological benefit, with good application prospect in production.展开更多
At present,China’s atmospheric environmental protection work has achieved initial results,but environmental protection is facing increasing pressure,and the environmental situation is still not optimistic.In response...At present,China’s atmospheric environmental protection work has achieved initial results,but environmental protection is facing increasing pressure,and the environmental situation is still not optimistic.In response to the call of the state,efforts have been intensified in environmental protection and ecological civilization construction,and supply-side structural reform has been actively promoted,and the Implementation Plan for Tianjin’s Comprehensive Discharge of Industrial Pollution Sources to Meet Standards has been promoted.When the total amount of pollutants discharged in key areas far exceeds the environmental capacity,regional heavy pollution weather will still occur once adverse meteorological conditions are encountered.In accordance with the Law of the People’s Republic of China on the Prevention and Control of Atmospheric Pollution,when the deterioration of air quality to a certain extent,to protect public health,key gas related industries should carry out emergency emission reduction in accordance with the local emergency plan while the local government starts the emergency response of heavy pollution weather.Direct economic loss of emergency response to heavy pollution weather is enormous.On the basis of meeting the total amount of emissions required by the state,the project aims to achieve the effect of"emission reduction and production increase"by precise emission reduction according to local characteristics.展开更多
Development of the medium and low voltage DC distribution system is of great significance to a regional transmission of electric energy,increasing a penetration rate of new energy,and enhancing a safety of the operati...Development of the medium and low voltage DC distribution system is of great significance to a regional transmission of electric energy,increasing a penetration rate of new energy,and enhancing a safety of the operation of the AC/DC interconnected grid.This paper first summarizes the medium and low voltage DC distribution system schemes and plans put forward by many countries,and then elaborate status of under-construction medium and low voltage DC distribution system project cases in China.Based on these project cases,this paper analyzes key issues involved in the medium and low voltage DC distribution system topologies,equipment,operation control technologies and DC fault protections,in order to provide theoretical and technical reference for future medium and low voltage DC distribution system-related projects.Finally,this paper combines a current China research status to summarize and give a prediction about the future research direction of medium and low voltage DC distribution system,which can provide reference for the research of medium and low voltage DC distribution system.展开更多
The non-linear dynamic theory brought a new method for recognizing and predicting complex non-linear dynamic behaviors. The non-linear behavior of vibration signals can be described by using fractal dimension quantita...The non-linear dynamic theory brought a new method for recognizing and predicting complex non-linear dynamic behaviors. The non-linear behavior of vibration signals can be described by using fractal dimension quantitatively. In this paper, a fractal dimension calculation method for discrete signals in the fractal theory was applied to extract the fractal dimension feature vectors and classified various fault types. Based on the wavelet packet transform, the energy feature vectors were extracted after the vibration signal was decomposed and reconstructed. Then, a wavelet neural network was used to recognize the mechanical faults. Finally, the fault diagnosis for a wind power system was taken as an example to show the method's feasibility.展开更多
Caligula Japonica has continuously broken out in large scale in Longnan City, Gansu Province of China, causing heavy economic losses. In order to ef- fectively control the insect and to increase the production benefit...Caligula Japonica has continuously broken out in large scale in Longnan City, Gansu Province of China, causing heavy economic losses. In order to ef- fectively control the insect and to increase the production benefit of walnut in Longnan, the authors have investigated and observed the morphological characters and living habits of C. Japonica. The major causes of continuous large-scale occurrence of C. Japonica in Longnan City are analyzed concretely, and the integrated con- trol measures are put forward from the aspects of silvicultural measures, physical control, chemical control and biological control.展开更多
The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collap...The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collapses,large deformations,rockbursts are frequently encountered,resulting in serious casualties and huge economic losses.This review mainly presents some representative results on microseismic(MS)monitoring and forecasting for disasters in hydropower underground engineering.First,a set of new denoising,spectral analysis,and location methods were developed for better identification and location of MS signals.Then,the tempo-spatial characteristics of MS events were analyzed to understand the relationship between field construction and damages of surrounding rocks.Combined with field construction,geological data,numerical simulation and parametric analysis of MS sources,the focal mechanism of MS events was revealed.A damage constitutive model considering MS fracturing size was put forward and feedback analysis considering the MS damage of underground surrounding rocks was conducted.Next,an MS multi-parameter based risk assessment and early warning method for dynamic disasters were proposed.The technology for control of the damage and deformation of underground surrounding rocks was proposed for underground caverns.Finally,two typical underground powerhouses were selected as case studies.These achievements can provide significant references for prevention and control of dynamic disasters for underground engineering with similar complicated geological conditions.展开更多
The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were ...The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were studied and three kinds of phenolic emulsifiers were prepared without catalyst in ethanol. The performance was researched that 2-({2-[2-(2-Amino-ethylamino)-ethylamino]-ethyl-amino}-methyl)-4- nonyl-phenol (abbreviated as TETA) could be used in micro-surface. With addition of 0.5 % demulsifier, the mixing time was extended to 120 seconds obviously, and the cohesion torque (60 min) was 2.8 N*m, which satisfied the opening traffic time shorter than 1 h. The wet track abrasion (6 d) was lower than 807 g/m2, with interracial modifier added, but the load wheel was increased with interfacial modifier increasing. When the TETA: demulsifier: interracial modifier =3:1:3, excellent performance was obtained and the experimental results met the International Slurry Surfacing Association (ISSA) standard. The synthesis process of this emulsifier is simple and the performance used in micro-surface was excellent, so this kind of emulsifier could have a better application future.展开更多
An adaptive backstepping sliding mode control approach is introduced to control the pitch motion of a rocket launcher. Its control law is proposed to guarantee that the control system is ultimately bounded in a Lyapun...An adaptive backstepping sliding mode control approach is introduced to control the pitch motion of a rocket launcher. Its control law is proposed to guarantee that the control system is ultimately bounded in a Lyapunov sense and make the servo system track the instruction of reference position globally and asymptotically. In addition, the sliding mode control can restrain the effects of parameter uncertainties and external disturbance. The functions of adaptive mechanism and sliding mode control are analyzed through the simulation in the different conditions.The simulation results illustrate that the method is applicable and robust.展开更多
基金Supported by 2024 Major Facility System Operating Costs of Ministry of Agriculture and Rural Affairs"Ledong Cashew Germplasm Resource Nursery Operating Cost of Ministry of Agriculture and Rural Affairs"2023-2024 Agricultural Germplasm Resource Conservation Project"Research on Collection,Conservation and Utilization of Cashew Germplasm Resources".
文摘In order to enhance the yield and quality of cashew,it is essential to implement high-yield cultivation techniques effectively throughout the production process.Additionally,pest control measures should be employed to provide technical support for the industrialized development of cashew.
基金the National Natural Science Foundation of China(Nos.52304141 and 52074154)。
文摘The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control results.This article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its effectiveness.The overview encompassed several key elements,delving into anchoring theory and grouting reinforcement theory.The new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also highlighted.The discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole pressure.An examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was conducted.Additionally,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting reinforcement.Furthermore,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable bolts.The application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was introduced.Finally,the existing problems in grouted bolting control technology for deep soft rock roadways are analyzed,and the future development trend of grouted bolting control technology is anticipated.
文摘Automatic control technology is the basis of road robot improvement,according to the characteristics of construction equipment and functions,the research will be input type perception from positioning acquisition,real-world monitoring,the process will use RTK-GNSS positional perception technology,by projecting the left side of the earth from Gauss-Krueger projection method,and then carry out the Cartesian conversion based on the characteristics of drawing;steering control system is the core of the electric drive unmanned module,on the basis of the analysis of the composition of the steering system of unmanned engineering vehicles,the steering system key components such as direction,torque sensor,drive motor and other models are established,the joint simulation model of unmanned engineering vehicles is established,the steering controller is designed using the PID method,the simulation results show that the control method can meet the construction path demand for automatic steering.The path planning will first formulate the construction area with preset values and realize the steering angle correction during driving by PID algorithm,and never realize the construction-based path planning,and the results show that the method can control the straight path within the error of 10 cm and the curve error within 20 cm.With the collaboration of various modules,the automatic construction simulation results of this robot show that the design path and control method is effective.
文摘The article mainly studies the application strategy of automatic addressable single-lamp control technology in tunnel lighting.It encompasses an introduction to this technology,an analysis of the tunnel lighting system using automatic addressable single-lamp control technology,and outlines the main development direction for this technology in modern tunnel lighting.The aim is to offer insights that can inform the rational deployment of this technology,thereby enhancing the lighting control effectiveness in modern tunnels and meeting their specific lighting requirements more effectively.
文摘China's infrastructure has gradually achieved large-scale development,and transportation construction has also shifted from east to west,transitioning from plains to mountainous areas.High-fill embankments of different sizes in mountainous areas are unavoidable,and the settlement of high-fill embankments is usually the most concerned issue in high-fill projects.According to the current research of highway projects,most of the high embankments in mountainous areas are soil-rock mixed embankments or rock-filled embankments,and their post-construction settlements are directly related to construction technology and the type of filler used.In this paper,the problems in the settlement control of earth-filled embankment and related factors are analyzed in detail.The settlement control technology of high-fill embankment in high-cold and high-altitude areas is also discussed,so as to ensure the overall quality of high-fill embankment.
基金The Scientific and Technology Researchand Development Program of Ministry of Railway of China(No.2008G005-A)the Fundamental Research Funds forthe Central Universities (No.SWJTU09BR042)
文摘On the basis of the theory of continuous compaction technology, we put forward the vibratory compaction value (VCV) index measured by a roller compactor, in order to evaluate the quality of continuously compacted subgrade. The relationships between the VCV index and the currently used indexes K30, Evd, Ev1 and Ev2, were explored by analyzing the experimental data collected from two test sections on the Beijing - Shanghai High-Speed Railway. The result shows that the VCV index has a linear relationship with the currently used indexes.
基金This project is supported by Provincial Science & Technology Projoct of Heilongjiang, China (No. GB05A501).
文摘Aiming at the characteristics of modularity and reconfigurable in open architecture computer numerical control (CNC) system, the open architecture CNC system, Harbin Institute of Tech- nology computer numerical control (HITCNC), is researched and manufactured based on the interface standards. The system's external interfaces are coincident with the corresponding international standards, and the internal interfaces follow the open modular architecture controller (OMAC) agreement. In the research and manufacturing process, object-oriented technology is used to ensure the openness of the HITCNC, and static programming is applied in the CNC system according to the idea of modularization disassembly. The HITCNC also actualizes real-time and unreal-time modules adopting real-time dynamical linked library (RTDLL) and component object model (COM). Finite state ma- chine (FSM) is adopted to do dynamically modeling of HITCNC. The complete separation between the software and the hardware is achieved in the HITCNC by applying the SoftSERCANS technique. The application of the above key techniques decreases the programming workload greatly, and uses software programs replacing hardware functions, which offers plenty technique ensures for the openness of HITCNC. Finally, based on the HITCNC, a three-dimensional milling system is established. On the system, series experiments are done to validate the expandability and interchangeability of HITCNC. The results of the experiments show that the established open architecture CNC system HITCNC is correct and feasible, and has good openness.
基金supported by the National Natural Science Foundation of China(Nos.52074296,52004286)the China Postdoctoral Science Foundation(Nos.2020T130701,2019M650895)the Fundamental Research Funds for the Central Universities(Nos.2022YJSNY18,2022XJNY02)。
文摘To ameliorate the defects of insufcient support resistance of traditional roadside flling bodies for gob-side entry retaining(GER),overcome the inability to adapt to the deformation of surrounding rock,and isolate the goaf efectively,a new type of high-water material as a roadside flling body for GER technology with double roadways was proposed.The instability analysis and control technology of GER with double roadways by flling high-water material into a gently inclined coal seam were studied.The basic mechanical properties of the new high-water material were investigated through laboratory experiments,and their main advantages were identifed.The reasonable width of the roadside flling wall of a high-water material was obtained by combining ground pressure observation and theoretical calculations.The distribution characteristics of the stress and plastic zone of surrounding rock of GER after being stabilized by the disturbance of the working face were studied using numerical simulations,and the failure range of GER by flling with high-water material was revealed.Based on this,a coupling control technology of anchor cables and bolts+single props+metal mesh+anchor bolts is proposed.Through the coupling methods of arranging borehole peeping and observing the convergences of surrounding rock,the results demonstrate that GER with double roadways by flling with a 1.8-m-wide high-water material has a good control efect.The above research will play an active role in promoting the application of high-water materials in GER roadside flling.
基金Sponsored by Foundation for Science Research Development of Nanjing University of Science and Technology
文摘Electrical system of military vehicle is a typical parameterized nonlinear system where complicated bifurcations may exist and threaten its safe and stable operation. An algebraic criterion for Hopf bifurcation is presented briefly and applied to find Hopf bifurcation point of the electrical system with automatic voltage regulator(AVR) dynamics in military vehicle. Hopf bifurcation controllers are designed for this electrical system by using wash-out filter,linear feedback,nonlinear feedback and their combination. The linear feedback control makes the system bring Hopf bifurcation at preferable parameter,the nonlinear feedback control modifies the type of the bifurcation,and the wash-out filter enhances the system damping,thus,the Hopf bifurcation is eliminated and the electrical system stability is ensured. Simulation results show the controller's validity.
基金Supported by Science and Technology Project of Science and Technology Department of Anhui Province in 2009"Research Topic on Bactrocera dorsalis"(09020303037)
文摘After systematic monitoring and field survey in orchard for three years from 2009 to 2011, it was found that Bactrocera dorsalis occurred for more than three generations each year on the north shore of the middle and lower reaches of Yangtze River, with overlapping generations; the activity peak of adults was from mid August to late September; the occurrence in citrus orchard in hilly and mountainous area was severe; the average insect-fruit rate in October reached 0.20% - 15.88% ; B. dorsalis had sporadic occurrence in other orchards. The integrated control measures of plowing in winter to kill pupae, removing insect-fruits, boycott- ing on the ground, trapping by sex attraetants and spraying pesticides could basically control the damage of B. dorsalis.
基金Supported by Key Laboratory of Characteristic Fruit Resources Research and Utilization in Liupanshui(5202020170203)College Students Program of Liupanshui Normal University(LPSSY-DXS17054)
文摘Kiwifruit root rot is an important root disease of kiwifruit, which has occurred increasingly in recent years. The disease leads to the death of whole kiwifruit plant under severe condition, and has become an important disease restricting kiwi fruit industry development. The characteris-tics, occurrence, etiology and symptoms of kiwifruit root rot were introduced in the paper, and the prevention and control technology against the dis-ease were put forward from the aspects of agriculture, biology and chemistry.
文摘Surface roughness considerably influences the stamping and coating performance of the automotive plates;however,the surface roughness of the automotive plates is transferred from the roll during the rolling process.Therefore,the variation and control technology regarding the roughness of the automotive plates and rolls has drawn increasing attention from researchers in China and around the globe.In this study,the research methods,analytical techniques,prediction models,transfer rules,and control technologies regarding the surface roughness of the automotive plates and rolls were reviewed.Among these,an online measurement system for automotive-plate and roll surface roughness has been applied to the production lines of Germany,China,Belgium,Holland,Austria,and other countries and has achieved remarkable results.Online measurement and timely feedback regarding the automotive-plate and roll surface roughness are needed to ensure favorable conditions for the establishment of automotive-plate roughness-control measurement.
基金Supported by Key Research and Development Program of Zhenjiang City(NY2020017)Independent Innovation Project of Agricultural Science and Technology of Jiangsu Province(CX[21]2019).
文摘In order to actively develop green ecological strawberry, the authors have studied integrated microecological prevention and control technologies of strawberry continuous cropping diseases, including increasing soil biomass and solar high temperature disinfection during strawberry greenhouse leisure period in summer, biological fertilizer (agent) treatment before colonization, root irrigation treatment with biocontrol agent, as well as appropriate amount of fulvic acid and cytex after colonization, forming a supporting technical system for the microecological prevention and control of soil-borne diseases in facilities. The demonstration application in production shows that the technology has the functions of restoring and enhancing soil biological fertility, enriching beneficial microbial flora, antagonizing harmful bacteria, significantly promoting the growth and development of strawberry, reducing the incidence of soil-borne diseases, reducing the use of chemical fertilizers and pesticides, promoting the early ripening and high yield of strawberry, significantly improving the quality and flavor of strawberry, reducing the risk of pesticide residues, and boosting consumer confidence, which further improves the economic benefit, social benefit and ecological benefit, with good application prospect in production.
文摘At present,China’s atmospheric environmental protection work has achieved initial results,but environmental protection is facing increasing pressure,and the environmental situation is still not optimistic.In response to the call of the state,efforts have been intensified in environmental protection and ecological civilization construction,and supply-side structural reform has been actively promoted,and the Implementation Plan for Tianjin’s Comprehensive Discharge of Industrial Pollution Sources to Meet Standards has been promoted.When the total amount of pollutants discharged in key areas far exceeds the environmental capacity,regional heavy pollution weather will still occur once adverse meteorological conditions are encountered.In accordance with the Law of the People’s Republic of China on the Prevention and Control of Atmospheric Pollution,when the deterioration of air quality to a certain extent,to protect public health,key gas related industries should carry out emergency emission reduction in accordance with the local emergency plan while the local government starts the emergency response of heavy pollution weather.Direct economic loss of emergency response to heavy pollution weather is enormous.On the basis of meeting the total amount of emissions required by the state,the project aims to achieve the effect of"emission reduction and production increase"by precise emission reduction according to local characteristics.
基金supported by the National Key Rese arch and Development Program of China(2018YFB0904100)Science and Technology Project of State Grid(SGHB0000KXJS1800685)
文摘Development of the medium and low voltage DC distribution system is of great significance to a regional transmission of electric energy,increasing a penetration rate of new energy,and enhancing a safety of the operation of the AC/DC interconnected grid.This paper first summarizes the medium and low voltage DC distribution system schemes and plans put forward by many countries,and then elaborate status of under-construction medium and low voltage DC distribution system project cases in China.Based on these project cases,this paper analyzes key issues involved in the medium and low voltage DC distribution system topologies,equipment,operation control technologies and DC fault protections,in order to provide theoretical and technical reference for future medium and low voltage DC distribution system-related projects.Finally,this paper combines a current China research status to summarize and give a prediction about the future research direction of medium and low voltage DC distribution system,which can provide reference for the research of medium and low voltage DC distribution system.
基金Sponsored by the National Science Foundation (61004118)the Natural Science Foundation Project of CQ CSTC (2011A70007)+1 种基金the Science and Technology Research Project of Chongqing Municipal Education Commission (KJ120422)the Science Foundation Project of Chongqing Jiaotong University Open Research Fund of Key Laboratory of Bridge Structural Engineering of Chongqing Jiaotong University (CQSLBF-Y11-5)
文摘The non-linear dynamic theory brought a new method for recognizing and predicting complex non-linear dynamic behaviors. The non-linear behavior of vibration signals can be described by using fractal dimension quantitatively. In this paper, a fractal dimension calculation method for discrete signals in the fractal theory was applied to extract the fractal dimension feature vectors and classified various fault types. Based on the wavelet packet transform, the energy feature vectors were extracted after the vibration signal was decomposed and reconstructed. Then, a wavelet neural network was used to recognize the mechanical faults. Finally, the fault diagnosis for a wind power system was taken as an example to show the method's feasibility.
基金Supported by Science and Technology Innovation Project of Gansu Province(2009GAAS38)
文摘Caligula Japonica has continuously broken out in large scale in Longnan City, Gansu Province of China, causing heavy economic losses. In order to ef- fectively control the insect and to increase the production benefit of walnut in Longnan, the authors have investigated and observed the morphological characters and living habits of C. Japonica. The major causes of continuous large-scale occurrence of C. Japonica in Longnan City are analyzed concretely, and the integrated con- trol measures are put forward from the aspects of silvicultural measures, physical control, chemical control and biological control.
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.42177143,42277461)the Science Foundation for Distinguished Young Scholars of Sichuan Province(Grant No.2020JDJQ0011).Thanks to the Chn Energy Dadu River Hydropower Development Co.,Ltd,China Three Gorges Construction Engineering Corporation,Yalong River Hydropower Development Company,Ltd,Power China Chengdu Engineering Co.,Ltd,Power China Northwest Engineering Co.,Ltd,Power China Sinohydro Bureau 7 Co.,Ltd,China Gezhouba Group No.1 Engineering Co.,Ltd.,and the 5th Engineering Co.,Ltd.of China Railway Construction Bridge Engineering Bureau Group for the support and assistance.
文摘The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collapses,large deformations,rockbursts are frequently encountered,resulting in serious casualties and huge economic losses.This review mainly presents some representative results on microseismic(MS)monitoring and forecasting for disasters in hydropower underground engineering.First,a set of new denoising,spectral analysis,and location methods were developed for better identification and location of MS signals.Then,the tempo-spatial characteristics of MS events were analyzed to understand the relationship between field construction and damages of surrounding rocks.Combined with field construction,geological data,numerical simulation and parametric analysis of MS sources,the focal mechanism of MS events was revealed.A damage constitutive model considering MS fracturing size was put forward and feedback analysis considering the MS damage of underground surrounding rocks was conducted.Next,an MS multi-parameter based risk assessment and early warning method for dynamic disasters were proposed.The technology for control of the damage and deformation of underground surrounding rocks was proposed for underground caverns.Finally,two typical underground powerhouses were selected as case studies.These achievements can provide significant references for prevention and control of dynamic disasters for underground engineering with similar complicated geological conditions.
基金Funded by the National Key Basic Research and Development Plan(No.2012CB724601)the Jiangsu Provincial Natural Science Foundation(No.BK 2008503)
文摘The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were studied and three kinds of phenolic emulsifiers were prepared without catalyst in ethanol. The performance was researched that 2-({2-[2-(2-Amino-ethylamino)-ethylamino]-ethyl-amino}-methyl)-4- nonyl-phenol (abbreviated as TETA) could be used in micro-surface. With addition of 0.5 % demulsifier, the mixing time was extended to 120 seconds obviously, and the cohesion torque (60 min) was 2.8 N*m, which satisfied the opening traffic time shorter than 1 h. The wet track abrasion (6 d) was lower than 807 g/m2, with interracial modifier added, but the load wheel was increased with interfacial modifier increasing. When the TETA: demulsifier: interracial modifier =3:1:3, excellent performance was obtained and the experimental results met the International Slurry Surfacing Association (ISSA) standard. The synthesis process of this emulsifier is simple and the performance used in micro-surface was excellent, so this kind of emulsifier could have a better application future.
基金Sponsored by the National Ministries Foundation(A2620061288)
文摘An adaptive backstepping sliding mode control approach is introduced to control the pitch motion of a rocket launcher. Its control law is proposed to guarantee that the control system is ultimately bounded in a Lyapunov sense and make the servo system track the instruction of reference position globally and asymptotically. In addition, the sliding mode control can restrain the effects of parameter uncertainties and external disturbance. The functions of adaptive mechanism and sliding mode control are analyzed through the simulation in the different conditions.The simulation results illustrate that the method is applicable and robust.