As a hot spot of next generation network, research over resource control has been carried out for years both in China and abroad. With a gradual progress in standardization, this field presents new development trends ...As a hot spot of next generation network, research over resource control has been carried out for years both in China and abroad. With a gradual progress in standardization, this field presents new development trends and features. Based on latest progresses in standardization promoted by ITU-T, TISPAN and 3GPP, new technologies concerned with resource control are introduced. Considering the problems faced in standardization deployment, relevant resource control functions are also analyzed in this article.展开更多
The pipeline all-position automatic welding machine system is a special welding system for automatically welding circumferential joint of pipeline on site, which has been widely used to the long-distance pipeline cons...The pipeline all-position automatic welding machine system is a special welding system for automatically welding circumferential joint of pipeline on site, which has been widely used to the long-distance pipeline construction projects due to the advantages of automatic control for welding parameters at all-position, moving speed of bugs and operating. In this paper, the key control technologies of PAWM all-position automatic welding machine ( developed by Pipeline Research Institute of CNPC) such us the automatic control system, control software, personal digital assistant (PDA) software and complex programmable logic device ( CPLD ) program as well us the control method of welding parameter have been described detailedly. With the higher welding quality, higher welding effwiency and lower labor intensity, PA WM all-position automatic welding machine has been successfully applied in many famous pipeline construction projects.展开更多
The control of civil, energy, and power systems presents significant new challenges for modeling and control theory. The purpose of this special issue is to provide a forum for researchers and practical engineers to d...The control of civil, energy, and power systems presents significant new challenges for modeling and control theory. The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil, energy, and power systems. Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling, control and decision. Topics of interest include modeling and control of, but are not limited to, the following:展开更多
Energy and power systems technology is a fundamental field in the civil engineering.Innovation in power generation,grid intelligence,renewable resources,propulsion and powertrains for transportation devices,etc.is a l...Energy and power systems technology is a fundamental field in the civil engineering.Innovation in power generation,grid intelligence,renewable resources,propulsion and powertrains for transportation devices,etc.is a long-term challenging theme for science and technology.Especially,improving the efficiency and the emission in energy con-展开更多
It is imperative to understand the spatial and temporal coordination deformation mechanism and develop targeted deformation control technologies for high sidewall—bottom transfixion(HSBT)zones to guarantee the stabil...It is imperative to understand the spatial and temporal coordination deformation mechanism and develop targeted deformation control technologies for high sidewall—bottom transfixion(HSBT)zones to guarantee the stability of rock surrounding underground hydro-powerhouses under complex geological conditions.In this study,the spatial and temporal coordinated deformation control of HSBT zones was addressed from the aspects of the deformation mechanism,failure characteristics,and control requirements,and some coordinated deformation control technologies were proposed.On this basis,a case study was conducted on the deformation control of the HSBT zone of the underground powerhouse at the Wudongde hydropower station,China.The results showed that the relationship between excavation and support,and the mismatch of deformation and support of the surrounding rock mass in the HSBT zone of underground caverns with a large span and high in-situ stress can be appropriately handled.The solution requires proper excavation and construction procedures,fine blasting control,composite and timely support,and real-time monitoring and dynamic feedback.The technologies proposed in this study will ensure the safe,high-quality,and orderly construction of the Baihetan and Wudongde underground caverns,and can be applied to other similar projects.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
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 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
Heavy metal pol ution, especial y cadmium pol ution, has threatened the safety production of rice. The research advance on law of absorption, distribution and accumulation of cadmium in rice and on recent safety contr...Heavy metal pol ution, especial y cadmium pol ution, has threatened the safety production of rice. The research advance on law of absorption, distribution and accumulation of cadmium in rice and on recent safety control technology of cadmium in rice grain was summarized in this paper. We hoped to lay a foundation for the safety production of rice.展开更多
[ Objective ] The study aimed to effectively and timely control the occurrence and damage of Rhyrthophorus femuneus Fabricius in Nanning City, Guangxi Province. [Method]The investigation on the distribution and damage...[ Objective ] The study aimed to effectively and timely control the occurrence and damage of Rhyrthophorus femuneus Fabricius in Nanning City, Guangxi Province. [Method]The investigation on the distribution and damage of R. ferrugineus was conducted in Nanning City, Guangxi Province. Its transmit ways were chocked, light trapping experiment, combination of artificial and chemical control, and chemical control were conducted. [ Result] The investigation indicated that there had distribution of R. ferrugineus in 70% plant nurseries and the scenic areas in Nanning City. Among the planted Hemp palm plants, the damaged vari- eties were up to 80%. The output of palm seedlings which had carried with pests was the main approach for spread and damage of R. ferrugineus. It was effective and feasible to use frequently vibration trapping light to trap adults. Pesticides were sprayed on the bellmouth of host ( central leaf), then aging leaf sheaths or agri- cultural film was used to strap tender leaf sheath in stalks, which could achieve the purpose of controlling R. femugineus. [ Conclusion ] The control strategies of R. femugineus should be focused on controlling seedlings and the plants with tree age less than ten year; the plants with long tree age and the tall plants should adopt selection control if it was necessary, and the integrated control should be implemented on the prevention measure.展开更多
[Objective] The aim was to screen economic and environment-friendly pesticides adaptive to aphid-resistant varieties in main rape growing regions of Yunnan Province.[Method] The effects of 6 pesticides against aphids ...[Objective] The aim was to screen economic and environment-friendly pesticides adaptive to aphid-resistant varieties in main rape growing regions of Yunnan Province.[Method] The effects of 6 pesticides against aphids on 22 Brassica campestris materials of the main breeds in Yunnan Province,the new improved varieties in China and the core breeding materials were tested.[Result] Yunyoushuang 1,Huayou 4,Yunhuayou Early-maturing Variety No.1 and A35 showed better aphid-resistance.An optimum pesticide application strategy was to use Diyaling in sowing time,and interchangeably apply nitenpyram and imidacloprid during flowering and pod formation stages.[Conclusion] The present study had provided an important technical support for sustainable development of rape industry.展开更多
Reproductive organ disease of geese is an endemic and multiple infectious disease in large-scale breeding of breeding geese, especially in anti-season production, which brings a great economic loss to goose production...Reproductive organ disease of geese is an endemic and multiple infectious disease in large-scale breeding of breeding geese, especially in anti-season production, which brings a great economic loss to goose production. To make effective prevention and control of reproductive organ disease of breeding geese under the anti-season breeding mode, the characteristics of control principles of infectious diseases of the poultry and the occurrence and prevalence of reproductive organ disease must be combined, so as to carry out scientific prevention and control.At the same time, according to the climate characteristics of summer, the feeding and management of breeding geese and water quality control should also be done well, and many corresponding measures should also be taken, thus obtaining better effect.展开更多
The production of maize is constrained by parasitic weeds, particularly Striga. A study was carried out to document farmers' knowledge, attitude and practices on Striga control among smallholder farmers across three ...The production of maize is constrained by parasitic weeds, particularly Striga. A study was carried out to document farmers' knowledge, attitude and practices on Striga control among smallholder farmers across three districts: Kisumu West, Busia and Teso South of Western Kenya. A multistage sampling technique was used to select the locations and farmers to be interviewed. A semi structured, open and closed ended questionnaire was administered leading to field experiment. Besides village meetings (39.2%), farmers got informed on farming methods under Striga weed farms and its control technologies through neighbours (2.5%), workshops and trainings (5.0%), field schools (3.7%), media (7.5%) and extension agents (10.8%). The attitudes of farmers towards Striga control varied but frequently cited: long term viability of the Striga seed (12.5%), difficult to control sharing of farm tools (10.8%), expensive technologies (13.3%), lack of adequate information (18.3%), labour intensive (15.0%), large farms for use of push and pull technology (1.7%) and time consuming (12.5%). Framers used various Striga control practices but traditional methods (25%) were among the most used (25%). Concerted effort involving researchers, extension agents and private sector are, therefore, required for wide scale dissemination and adoption of the existing modem control technologies.展开更多
Based on deformation and failure characteristics of the second belt conveyor roadway at level II of Zhuxianzhuang coal mine, laboratory experiments, numerical calculation and field test were adopted to analyze the com...Based on deformation and failure characteristics of the second belt conveyor roadway at level II of Zhuxianzhuang coal mine, laboratory experiments, numerical calculation and field test were adopted to analyze the composition and microstructure of mudstone, the law of mudstone hydration and its strength weakening induced by water, the characteristics of surrounding rock deformation and failure under the action of confined water. Results showed that montmorillonite clay minerals accounted for as much as 76% of mudstone, with a large number of pores existing in the microstructure. Besides, as the molecular structure of montmorillonite changed, mudstone microstructure damage occurred with the macroscopic manifestation of its theological instability. Weakening degree of confined water on residual strength of mudstone was almost 50%. The instability mechanism of soft rock roadway caused by high confined water is that surrounding rock circulates the process of "fracture-seepage-mud ding-closed" twice, which weakens its strength and leads to roadway instability. A combined support technology, namely the, "high-toughness sealing layer + hollow grouting cables + full-length anchoring bolts with deep borehole" was proposed. Based on field observation, the soft rock roadway was controlled effectively, which also verified the effectiveness of new control technology for surrounding rock.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
By reviewing the mechanisms of drilling fluid lost circulation and its control in fractured formations, the applicability and working mechanisms of different kinds of lost circulation materials in plugging fractured f...By reviewing the mechanisms of drilling fluid lost circulation and its control in fractured formations, the applicability and working mechanisms of different kinds of lost circulation materials in plugging fractured formations have been summarized. Meanwhile, based on the types of lost circulation materials, the advantages, disadvantages, and application effects of corresponding plugging technologies have been analyzed to sort out the key problems existing in the current lost circulation control technologies. On this basis, the development direction of plugging technology for severe loss have been pointed out. It is suggested that that the lost circulation control technology should combine different disciplines such as geology, engineering and materials to realize integration, intelligence and systematization in the future. Five research aspects should be focused on:(1) the study on mechanisms of drilling fluid lost circulation and its control to provide basis for scientific selection of lost circulation material formulas, control methods and processes;(2) the research and development of self-adaptive lost circulation materials to improve the matching relationship between lost control materials and fracture scales;(3) the research and development of lost circulation materials with strong retention and strong filling in three-dimensional fracture space, to enhance the retention and filling capacities of materials in fractures and improve the lost circulation control effect;(4) the research and development of lost circulation materials with high temperature tolerance, to ensure the long-term plugging effect of deep high-temperature formations;(5) the study on digital and intelligent lost circulation control technology, to promote the development of lost circulation control technology to digital and intelligent direction.展开更多
In order to achieve higher efficient cohesion match of procedure and equipment between ironmaking and steelmaking interface, the theory of multi-dimensional material flow control was applied to analyze torpedo ladle-i...In order to achieve higher efficient cohesion match of procedure and equipment between ironmaking and steelmaking interface, the theory of multi-dimensional material flow control was applied to analyze torpedo ladle-iron ladle transportation process between blast furnace and basic oxygen furnace. Moreover, basic parameters of material flow were analyzed and optimized, such as time, temperature and material quantity. Based on operating principles of material flow, control methods were optimized, such as product organization mode, scheduling discipline and scheduling plan of hot metal ladle. Finally, the material flow control technology of ironmaking and steelmaking interface was integrated. Satisfactory effects are obtained after applying the technology in practice. The total turnover number of torpedo ladle decreases from 20 to 18, the hot metal temperature of 1# BF torpedo ladle decreases from 36 °C to 19.5 °C, the hot metal temperature of 2# BF torpedo ladle decreases from 36.6 °C to 19.8 °C, the temperature drop of desulfurization hot metal decreases by 4 °C, and the temperature drop of non-desulfurization hot metal decreases by 2.8 °C. Furthermore, the ironmaking and steelmaking interface system will realize high-efficiency control by using this control technology.展开更多
The Jinping I hydropower station is a huge water conservancy project consisting of the highest concrete arch dam to date in the world and a highly complex and large underground powerhouse cavern. It is located on the ...The Jinping I hydropower station is a huge water conservancy project consisting of the highest concrete arch dam to date in the world and a highly complex and large underground powerhouse cavern. It is located on the right bank with extremely high in-situ stress and a few discontinuities observed in surrounding rock masses. The problems of rock mass deformation and failure result in considerable challenges related to project design and construction and have raised a wide range of concerns in the fields of rock mechanics and engineering. During the excavation of underground caverns, high in-situ stress and relatively low rock mass strength in combination with large excavation dimensions lead to large deformation of the surrounding rock mass and support. Existing experiences in excavation and support cannot deal with the large deformation of rock mass effectively, and further studies are needed. In this paper, the geological conditions, layout of caverns, and design of excavation and support are first introduced, and then detailed analyses of deformation and failure characteristics of rocks are presented. Based on this, the mechanisms of deformation and failure are discussed, and the support adjustments for controlling rock large deformation and subsequent excavation procedures are proposed. Finally, the effectiveness of support and excavation adjustments to maintain the stability of the rock mass is verified. The measures for controlling the large deformation of surrounding rocks enrich the practical experiences related to the design and construction of large underground openings, and the construction of caverns in the Jinping I hydropower station provides a good case study of large-scale excavation in highly stressed ground with complex geological structures, as well as a reference case for research on rock mechanics.展开更多
The stability control of longwall coalface is the key technology of large-cutting-height mining method.Therefore,a systematic study of the factors that affect coalface stability and its control technology is required ...The stability control of longwall coalface is the key technology of large-cutting-height mining method.Therefore,a systematic study of the factors that affect coalface stability and its control technology is required in the development of large-cutting-height mining method in China. After the practical field observation and years of study,it was found that the more than 95% of failures in coalface are shear failure. The shear failure analysis model of coalface has been established,that can perform systematic study among factors such as mining height,coal mass strength,roof load,support resistance,and face flipper protecting plate horizontal force. Meanwhile,sensitivity analysis of factors influencing coalface stability showed that improving support capacity,cohesion of coal mass and decreasing roof load of coalface are the key to improve coalface stability. Numerical simulation of the factors affecting coalface stability has been performed using UDEC software and the results are consistent with the theoretical analysis. The coalface reinforcement technology of large-cutting-height mining method using the grouting combined with coir rope is presented. Laboratory tests have been carried out to verify its reinforcement effect and practical application has been implemented in several coal mines with good results.It has now become the main technology to reduce longwall coalface failure of large-cutting-height mining method.展开更多
Surrounding rock control in the overlying protective coal seam is a challenging topic for de-stressed mining of multi-seamed coal.Current research findings on roadway control were used in the design of a physical mode...Surrounding rock control in the overlying protective coal seam is a challenging topic for de-stressed mining of multi-seamed coal.Current research findings on roadway control were used in the design of a physical model of a complex textured roof having a varying thickness.The model was used to study roadway instability and collapse caused by dynamic pressure.The results show that when the thickness of the roof exceeds the bolted depth the roadway security is least and the roof has the greatest possibility for collapse.Numerical simulations were also carried out to study stress redistribution before and after roadway excavation during underlying protective seam mining.The evolution of roadway displacement and fracture,as affected by support methods,has been well studied.A series of support principles and technologies for mining affected roadways has been proposed after demonstration of successful practical application in the Huainan Mines.These principles and technologies are of extended value to deep coal mining support in China.展开更多
文摘As a hot spot of next generation network, research over resource control has been carried out for years both in China and abroad. With a gradual progress in standardization, this field presents new development trends and features. Based on latest progresses in standardization promoted by ITU-T, TISPAN and 3GPP, new technologies concerned with resource control are introduced. Considering the problems faced in standardization deployment, relevant resource control functions are also analyzed in this article.
文摘The pipeline all-position automatic welding machine system is a special welding system for automatically welding circumferential joint of pipeline on site, which has been widely used to the long-distance pipeline construction projects due to the advantages of automatic control for welding parameters at all-position, moving speed of bugs and operating. In this paper, the key control technologies of PAWM all-position automatic welding machine ( developed by Pipeline Research Institute of CNPC) such us the automatic control system, control software, personal digital assistant (PDA) software and complex programmable logic device ( CPLD ) program as well us the control method of welding parameter have been described detailedly. With the higher welding quality, higher welding effwiency and lower labor intensity, PA WM all-position automatic welding machine has been successfully applied in many famous pipeline construction projects.
文摘The control of civil, energy, and power systems presents significant new challenges for modeling and control theory. The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil, energy, and power systems. Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling, control and decision. Topics of interest include modeling and control of, but are not limited to, the following:
文摘Energy and power systems technology is a fundamental field in the civil engineering.Innovation in power generation,grid intelligence,renewable resources,propulsion and powertrains for transportation devices,etc.is a long-term challenging theme for science and technology.Especially,improving the efficiency and the emission in energy con-
基金This work is supported by the National Natural Science Foundation of China(Nos.51979146 and 12102230)the China Three Gorges Corporation Research Program(Nos.WDD/0490,WDD/0578,and BHT/0774)the China Postdoctoral Science Foundation(No.2022M711862).
文摘It is imperative to understand the spatial and temporal coordination deformation mechanism and develop targeted deformation control technologies for high sidewall—bottom transfixion(HSBT)zones to guarantee the stability of rock surrounding underground hydro-powerhouses under complex geological conditions.In this study,the spatial and temporal coordinated deformation control of HSBT zones was addressed from the aspects of the deformation mechanism,failure characteristics,and control requirements,and some coordinated deformation control technologies were proposed.On this basis,a case study was conducted on the deformation control of the HSBT zone of the underground powerhouse at the Wudongde hydropower station,China.The results showed that the relationship between excavation and support,and the mismatch of deformation and support of the surrounding rock mass in the HSBT zone of underground caverns with a large span and high in-situ stress can be appropriately handled.The solution requires proper excavation and construction procedures,fine blasting control,composite and timely support,and real-time monitoring and dynamic feedback.The technologies proposed in this study will ensure the safe,high-quality,and orderly construction of the Baihetan and Wudongde underground caverns,and can be applied to other similar projects.
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.
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.
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.
基金Supported by the Twelfth Five-Year National Science and Technology Support Project(2012BAK17B03)National Nature Science Foundation of China(31401356)+1 种基金College Students’ Science and Technology Innovation Activities Project Plan(New Talent Plan) in Zhejiang Province(2013R409036)National College Students’ Innovative Entrepreneurial Training Program~~
文摘Heavy metal pol ution, especial y cadmium pol ution, has threatened the safety production of rice. The research advance on law of absorption, distribution and accumulation of cadmium in rice and on recent safety control technology of cadmium in rice grain was summarized in this paper. We hoped to lay a foundation for the safety production of rice.
基金Supported by Natural Science and Technology Fund Project in Guangxi Vocational Technical College of Agriculture(B070206)~~
文摘[ Objective ] The study aimed to effectively and timely control the occurrence and damage of Rhyrthophorus femuneus Fabricius in Nanning City, Guangxi Province. [Method]The investigation on the distribution and damage of R. ferrugineus was conducted in Nanning City, Guangxi Province. Its transmit ways were chocked, light trapping experiment, combination of artificial and chemical control, and chemical control were conducted. [ Result] The investigation indicated that there had distribution of R. ferrugineus in 70% plant nurseries and the scenic areas in Nanning City. Among the planted Hemp palm plants, the damaged vari- eties were up to 80%. The output of palm seedlings which had carried with pests was the main approach for spread and damage of R. ferrugineus. It was effective and feasible to use frequently vibration trapping light to trap adults. Pesticides were sprayed on the bellmouth of host ( central leaf), then aging leaf sheaths or agri- cultural film was used to strap tender leaf sheath in stalks, which could achieve the purpose of controlling R. femugineus. [ Conclusion ] The control strategies of R. femugineus should be focused on controlling seedlings and the plants with tree age less than ten year; the plants with long tree age and the tall plants should adopt selection control if it was necessary, and the integrated control should be implemented on the prevention measure.
基金Supported by National Science and Technology Supporting Project (2009BADA8B01,2010BAD01B04)Kunming Comprehensive Experimental Station,National Modern Agricultural Rape Industrial Technology System(NYCYTX-00564)Development of the Yunnan Modern Agricultural Rape Industrial Technology System~~
文摘[Objective] The aim was to screen economic and environment-friendly pesticides adaptive to aphid-resistant varieties in main rape growing regions of Yunnan Province.[Method] The effects of 6 pesticides against aphids on 22 Brassica campestris materials of the main breeds in Yunnan Province,the new improved varieties in China and the core breeding materials were tested.[Result] Yunyoushuang 1,Huayou 4,Yunhuayou Early-maturing Variety No.1 and A35 showed better aphid-resistance.An optimum pesticide application strategy was to use Diyaling in sowing time,and interchangeably apply nitenpyram and imidacloprid during flowering and pod formation stages.[Conclusion] The present study had provided an important technical support for sustainable development of rape industry.
基金Supported by Agricultural Science and Technology Supporting Program of Huai'an City in Jiangsu Province(No.:SN13057)~~
文摘Reproductive organ disease of geese is an endemic and multiple infectious disease in large-scale breeding of breeding geese, especially in anti-season production, which brings a great economic loss to goose production. To make effective prevention and control of reproductive organ disease of breeding geese under the anti-season breeding mode, the characteristics of control principles of infectious diseases of the poultry and the occurrence and prevalence of reproductive organ disease must be combined, so as to carry out scientific prevention and control.At the same time, according to the climate characteristics of summer, the feeding and management of breeding geese and water quality control should also be done well, and many corresponding measures should also be taken, thus obtaining better effect.
文摘The production of maize is constrained by parasitic weeds, particularly Striga. A study was carried out to document farmers' knowledge, attitude and practices on Striga control among smallholder farmers across three districts: Kisumu West, Busia and Teso South of Western Kenya. A multistage sampling technique was used to select the locations and farmers to be interviewed. A semi structured, open and closed ended questionnaire was administered leading to field experiment. Besides village meetings (39.2%), farmers got informed on farming methods under Striga weed farms and its control technologies through neighbours (2.5%), workshops and trainings (5.0%), field schools (3.7%), media (7.5%) and extension agents (10.8%). The attitudes of farmers towards Striga control varied but frequently cited: long term viability of the Striga seed (12.5%), difficult to control sharing of farm tools (10.8%), expensive technologies (13.3%), lack of adequate information (18.3%), labour intensive (15.0%), large farms for use of push and pull technology (1.7%) and time consuming (12.5%). Framers used various Striga control practices but traditional methods (25%) were among the most used (25%). Concerted effort involving researchers, extension agents and private sector are, therefore, required for wide scale dissemination and adoption of the existing modem control technologies.
基金the Natural Science Foundation of Jiangsu Province(No.BK20141130)the Fundamental Research Funds for the Central Universities(No.2014QNB27)
文摘Based on deformation and failure characteristics of the second belt conveyor roadway at level II of Zhuxianzhuang coal mine, laboratory experiments, numerical calculation and field test were adopted to analyze the composition and microstructure of mudstone, the law of mudstone hydration and its strength weakening induced by water, the characteristics of surrounding rock deformation and failure under the action of confined water. Results showed that montmorillonite clay minerals accounted for as much as 76% of mudstone, with a large number of pores existing in the microstructure. Besides, as the molecular structure of montmorillonite changed, mudstone microstructure damage occurred with the macroscopic manifestation of its theological instability. Weakening degree of confined water on residual strength of mudstone was almost 50%. The instability mechanism of soft rock roadway caused by high confined water is that surrounding rock circulates the process of "fracture-seepage-mud ding-closed" twice, which weakens its strength and leads to roadway instability. A combined support technology, namely the, "high-toughness sealing layer + hollow grouting cables + full-length anchoring bolts with deep borehole" was proposed. Based on field observation, the soft rock roadway was controlled effectively, which also verified the effectiveness of new control technology for surrounding rock.
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Supported by National Natural Science Foundation of China(51991361,52074327,U1762212)Major Engineering Technology Field Tes Project of CNPC(2020F-45)。
文摘By reviewing the mechanisms of drilling fluid lost circulation and its control in fractured formations, the applicability and working mechanisms of different kinds of lost circulation materials in plugging fractured formations have been summarized. Meanwhile, based on the types of lost circulation materials, the advantages, disadvantages, and application effects of corresponding plugging technologies have been analyzed to sort out the key problems existing in the current lost circulation control technologies. On this basis, the development direction of plugging technology for severe loss have been pointed out. It is suggested that that the lost circulation control technology should combine different disciplines such as geology, engineering and materials to realize integration, intelligence and systematization in the future. Five research aspects should be focused on:(1) the study on mechanisms of drilling fluid lost circulation and its control to provide basis for scientific selection of lost circulation material formulas, control methods and processes;(2) the research and development of self-adaptive lost circulation materials to improve the matching relationship between lost control materials and fracture scales;(3) the research and development of lost circulation materials with strong retention and strong filling in three-dimensional fracture space, to enhance the retention and filling capacities of materials in fractures and improve the lost circulation control effect;(4) the research and development of lost circulation materials with high temperature tolerance, to ensure the long-term plugging effect of deep high-temperature formations;(5) the study on digital and intelligent lost circulation control technology, to promote the development of lost circulation control technology to digital and intelligent direction.
基金Project(2011FZ056)supported by the Applied Basic Research Plan Program of Yunnan Province,China
文摘In order to achieve higher efficient cohesion match of procedure and equipment between ironmaking and steelmaking interface, the theory of multi-dimensional material flow control was applied to analyze torpedo ladle-iron ladle transportation process between blast furnace and basic oxygen furnace. Moreover, basic parameters of material flow were analyzed and optimized, such as time, temperature and material quantity. Based on operating principles of material flow, control methods were optimized, such as product organization mode, scheduling discipline and scheduling plan of hot metal ladle. Finally, the material flow control technology of ironmaking and steelmaking interface was integrated. Satisfactory effects are obtained after applying the technology in practice. The total turnover number of torpedo ladle decreases from 20 to 18, the hot metal temperature of 1# BF torpedo ladle decreases from 36 °C to 19.5 °C, the hot metal temperature of 2# BF torpedo ladle decreases from 36.6 °C to 19.8 °C, the temperature drop of desulfurization hot metal decreases by 4 °C, and the temperature drop of non-desulfurization hot metal decreases by 2.8 °C. Furthermore, the ironmaking and steelmaking interface system will realize high-efficiency control by using this control technology.
文摘The Jinping I hydropower station is a huge water conservancy project consisting of the highest concrete arch dam to date in the world and a highly complex and large underground powerhouse cavern. It is located on the right bank with extremely high in-situ stress and a few discontinuities observed in surrounding rock masses. The problems of rock mass deformation and failure result in considerable challenges related to project design and construction and have raised a wide range of concerns in the fields of rock mechanics and engineering. During the excavation of underground caverns, high in-situ stress and relatively low rock mass strength in combination with large excavation dimensions lead to large deformation of the surrounding rock mass and support. Existing experiences in excavation and support cannot deal with the large deformation of rock mass effectively, and further studies are needed. In this paper, the geological conditions, layout of caverns, and design of excavation and support are first introduced, and then detailed analyses of deformation and failure characteristics of rocks are presented. Based on this, the mechanisms of deformation and failure are discussed, and the support adjustments for controlling rock large deformation and subsequent excavation procedures are proposed. Finally, the effectiveness of support and excavation adjustments to maintain the stability of the rock mass is verified. The measures for controlling the large deformation of surrounding rocks enrich the practical experiences related to the design and construction of large underground openings, and the construction of caverns in the Jinping I hydropower station provides a good case study of large-scale excavation in highly stressed ground with complex geological structures, as well as a reference case for research on rock mechanics.
基金financial support from National Basic Research Program of China (No.2013CB227903)the National Natural Science Foundation of General Program of China (No.51574244)the Joint Funds of the National Natural Science Foundation of China (No.U1361209) are greatly appreciated
文摘The stability control of longwall coalface is the key technology of large-cutting-height mining method.Therefore,a systematic study of the factors that affect coalface stability and its control technology is required in the development of large-cutting-height mining method in China. After the practical field observation and years of study,it was found that the more than 95% of failures in coalface are shear failure. The shear failure analysis model of coalface has been established,that can perform systematic study among factors such as mining height,coal mass strength,roof load,support resistance,and face flipper protecting plate horizontal force. Meanwhile,sensitivity analysis of factors influencing coalface stability showed that improving support capacity,cohesion of coal mass and decreasing roof load of coalface are the key to improve coalface stability. Numerical simulation of the factors affecting coalface stability has been performed using UDEC software and the results are consistent with the theoretical analysis. The coalface reinforcement technology of large-cutting-height mining method using the grouting combined with coir rope is presented. Laboratory tests have been carried out to verify its reinforcement effect and practical application has been implemented in several coal mines with good results.It has now become the main technology to reduce longwall coalface failure of large-cutting-height mining method.
基金Financial support for this work,provided by the National Key Technology R&D Program(No.2007BAK28B00)the National Natural Science Foundation for the Youth of China(No.50904064)+2 种基金the Research Fund for the Youth of China University of Mining & Technology(No.2008A004)the State Key Laboratory of Coal Resources and Safe Mining,CUMT(No.SKLCRSM09X03)the Research Fund of the State Key Laboratory of Coal Resources and Mine Safety,CUMT(No.08KF10)
文摘Surrounding rock control in the overlying protective coal seam is a challenging topic for de-stressed mining of multi-seamed coal.Current research findings on roadway control were used in the design of a physical model of a complex textured roof having a varying thickness.The model was used to study roadway instability and collapse caused by dynamic pressure.The results show that when the thickness of the roof exceeds the bolted depth the roadway security is least and the roof has the greatest possibility for collapse.Numerical simulations were also carried out to study stress redistribution before and after roadway excavation during underlying protective seam mining.The evolution of roadway displacement and fracture,as affected by support methods,has been well studied.A series of support principles and technologies for mining affected roadways has been proposed after demonstration of successful practical application in the Huainan Mines.These principles and technologies are of extended value to deep coal mining support in China.