This paper investigates the damage symptoms and occurrence regularity related to coffee leaf rust,and proposes a comprehensive prevention and control strategy grounded in the principle of prioritizing prevention and i...This paper investigates the damage symptoms and occurrence regularity related to coffee leaf rust,and proposes a comprehensive prevention and control strategy grounded in the principle of prioritizing prevention and implementing integrated prevention and control.This strategy encompasses the cultivation of rust-resistant varieties,the implementation of agricultural practices,the application of chemical interventions,the utilization of hyperparasitic fungi,and the protection and utilization of natural enemies.The paper further outlines the necessary requirements for effective prevention and control,emphasizing the importance of enhancing responsibility implementation,fostering systematic prevention and control measures,enhancing guidance services,and increasing publicity and guidance.The aim is to offer technical guidance for the integrated prevention and control of coffee leaf rust in Yunnan Province.展开更多
External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper preventi...External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper prevention and control measures.We reviewed literature on risk identification of underground pressure pipelines damage due to external disturbance was conducted,and a list of risk factors was formed.Based on the list of risk factors,fault tree analysis was carried out on underground pressure pipelines damage caused by external disturbances,and risk prevention and control measures were proposed through the calculation of minimum cut sets,minimum path sets,and structural importance,in hopes of providing reference for the normal operation of underground pressure pipelines.展开更多
[Objective] The aim was to develop prevention and control approaches of diseases and pests of Siraitia grosvenori. [Method] Long-term observation was con- ducted on cultivation methods of Siraitia grosvenori in the ga...[Objective] The aim was to develop prevention and control approaches of diseases and pests of Siraitia grosvenori. [Method] Long-term observation was con- ducted on cultivation methods of Siraitia grosvenori in the gardens in Longjiang Vil- lage of Yongfu County to conclude the prevention methods. [Result] Siraitia grosvenori yield can be reduced by nine diseases, such as root knot nematode dis- ease, and eight pests, such as Brachytrupes portentosus. [Conclusion] It would be effective for prevention of diseases and pests and guarantee quality and yield of Luohan guo to manage the gardens dominated by biological control and supple- mented by pesticide as per crop rotation.展开更多
Stress sensitivity and water blocking in fractured carbonate reservoir formations with low permeability were determined as the main potential damage mechanisms during drilling and completion operations in the ancient ...Stress sensitivity and water blocking in fractured carbonate reservoir formations with low permeability were determined as the main potential damage mechanisms during drilling and completion operations in the ancient buried hill Ordovician reservoirs in the Tarim Basin. Geological structure, lithology, porosity, permeability and mineral components all affect the potential for formation damage. The experimental results showed that the permeability loss was 83.8%-98.6% caused by stress sensitivity, and was 27.9%-48.1% caused by water blocking. Based on the experimental results, several main conclusions concerning stress sensitivity can be drawn as follows： the lower the core permeability and the smaller the core fracture width, the higher the stress sensitivity. Also, stress sensitivity results in lag effect for both permeability recovery and fracture closure. Aimed at the mechanisms of formation damage, a modified low-damage mixed metal hydroxide （MMH） drilling fluid system was developed, which was mainly composed of low-fluorescence shale control agent, filtration control agent, lowfluorescence lubricant and surfactant. The results of experimental evaluation and field test showed that the newly-developed drilling fluid and engineering techniques provided could dramatically increase the return permeability （over 85%） of core samples. This drilling fluid had such advantages as good rheological and lubricating properties, high temperature stability, and low filtration rate （API filtration less than 5 ml after aging at 120 ℃ for 4 hours）. Therefore, fractured carbonate formations with low permeability could be protected effectively when drilling with the newly-developed drilling fluid. Meanwhile, field test showed that both penetration rate and bore stability were improved and the soaking time of the drilling fluid with formation was sharply shortened, indicating that the modified MMH drilling fluid could meet the requirements of drilling engineering and geology.展开更多
The pathogenic characteristics of scab-anthracnoge of Fatsia japonica was introduced,and the infection cycle,occurrence regularity and main harmful symptoms of the disease were elaborated.Prevention is the main method...The pathogenic characteristics of scab-anthracnoge of Fatsia japonica was introduced,and the infection cycle,occurrence regularity and main harmful symptoms of the disease were elaborated.Prevention is the main method to prevent scab-anthracnoge of F.japonica,and disease-free seedlings should be cultivated.Meantime,cultivation management should be strengthened to improve disease resistance of plant,and chemical agents must be timely sprayed in the early incidence stage,in order to achieve the purpose of comprehensive control.展开更多
[ Objective ] The aim was to study the influence of filamentous algae on the process of water ecological purification. [ Method ] The occurrence mechanism of filamentous algae and its ecological system were summarized...[ Objective ] The aim was to study the influence of filamentous algae on the process of water ecological purification. [ Method ] The occurrence mechanism of filamentous algae and its ecological system were summarized and analyzed. Considering the ecological purification in north- ern Jiangsu, the occurrence and prevention of filamentous algae in water, the method to prevent filamentous algae in polluted water was discussed. [ Result] The results showed that by measures of improving planting density, regular harvesting, and water flow state control before the filamentous algae blooming period, together with improving local pH value, light interference and ecological control during the blooming period, can effectively control the filamentous algae blooming. [ Condusion] The study of the happening mechanism of filamentous algae provided theoretical references and the technical basis in the work of filamentous algae prevention and control.展开更多
The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to d...The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.展开更多
Since 2002,Hami City,Xinjiang Province,has implemented"construction project of rodent-free demonstration area".Artificial eagle frames are installed on the grassland to control rodent damage,receiving remark...Since 2002,Hami City,Xinjiang Province,has implemented"construction project of rodent-free demonstration area".Artificial eagle frames are installed on the grassland to control rodent damage,receiving remarkable control effect.The rodent density in the treatment area is below the threshold of hazard.Moreover,the implementation of the project increases the grassland biomass and improves the vegetation coverage,receiving good economic,ecological and social benefits.展开更多
Ceracris kiangsu Tsai is one of the most widely distributed forest pest.C.kiangsu has migrated from Laos to China this year,with many migration peaks and large population numbers.The main sources of C.kiangsu were fro...Ceracris kiangsu Tsai is one of the most widely distributed forest pest.C.kiangsu has migrated from Laos to China this year,with many migration peaks and large population numbers.The main sources of C.kiangsu were from abroad and a small number of native insect sources exist.Most of the immigration sources were from Laos,and a small part originated from Vietnam.The frontier region of Yunnan Province is suitable for the growth of C.kiangsu.It is speculated that the migration frequency of the C.kiangsu from abroad may increase in recent years.In this paper,the typical morphological characteristics,life history,biological characteristics and prevention and control measures of C.kiangsu were summarized.Based on the characteristics of C.kiangsu,and combining actual sugarcane production condition in Yunnan sugarcane areas,we put forward prevention and control strategies and measures.It is suggested that Yunnan Sugarcane areas should pay close attention to the occurrence of C.kiangsu in neighboring countries,monitor the C.kiangsu population dynamics and update pest forecast information in time,and detect and control C.kiangsu in the early period,in order to effectively prevent C.kiangsu and ensure the safety of sugarcane production.展开更多
By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,me...By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.展开更多
The shortage of water resources is severe in Beijing. The shortage of eco-environmental water and the sewage discharge over the environmental capacity are main bottlenecks that restrict the improvement of water enviro...The shortage of water resources is severe in Beijing. The shortage of eco-environmental water and the sewage discharge over the environmental capacity are main bottlenecks that restrict the improvement of water environment. The reuse of wastewater could not only reduce the discharge of pollutants,but it could also increase the consumption of eco-environmental water. Therefore the reuse of wastewater is an important approach to improve the water environmental quality. Combined with the formulation process of Regulations of Beijing on Prevention and Control of Water Pollution,the current situations of prevention and control of water pollution in Beijing,the discharge of pollutant,water environmental quality,the population and economic development and water resources and so on were analyzed. And the bottlenecks that restricted the improvement of water environmental quality were found. And the necessity of solving the control of water pollution by reusing the wastewater and ensuring the consumption of eco-environmental water was analyzed from the perspective of the control of water pollution. And some legislative countermeasures were put forward,which provided new ideas for solving the problem of the prevention and control of water pollution and improving the water environmental quality. It was of important reference values for local governments（ especially water-deficient regions） to make relative polices or plans of water pollution control and water environmental protection.展开更多
Water supply project of drawing from the Songhua River in central cities of Jilin is taken as research object.On the basis of analyzing project characteristics and natural conditions of the project area,site selection...Water supply project of drawing from the Songhua River in central cities of Jilin is taken as research object.On the basis of analyzing project characteristics and natural conditions of the project area,site selection of waste slag yard of water diversion project and design of water and soil conservation measures are discussed.Rationality of site selection of waste slag yard and pertinence of prevention and control measures of water and soil loss in waste slag yard are analyzed,and comprehensive utilization of waste slag in large-scale production and construction projects is explored.展开更多
Shale gas reservoirs are unconventional tight gas reservoirs,in which horizontal wells and hydraulic fracturing are required to achieve commercial development.The fracture networks created by hydraulic fracturing can ...Shale gas reservoirs are unconventional tight gas reservoirs,in which horizontal wells and hydraulic fracturing are required to achieve commercial development.The fracture networks created by hydraulic fracturing can increase the drainage area extensively to enhance shale gas recovery.However,large volumes of fracturing fluid that is difficult to flow back to the surface and remained in the shale formation,will inevitably lead to damages of the shale formations and limit the effectiveness of stimulation.Supercritical water(SCW)treatment after hydraulic fracturing is a new method to enhance shale gas recovery by using appropriate heat treatment methods to the specific formation to convert the retained fracturing fluid into a supercritical state(at temperatures in excess of 373.946°C and pressures in excess of 22.064 MPa).An experiment was conducted to simulate the reaction between shale and SCW,and the capacity of SCW treatment to enhance the permeability of the shale was evaluated by measuring the response of the shale porosity and permeability on SCW treatment.The experimental results show that the shale porosity and permeability increase by 213.43%and 2198.37%,respectively.The pore structure alteration and permeability enhancement of the shale matrix were determined by analyzing the changes in pore structure and mineral composition after SCW treatment.The mechanisms that affect pore structure and mineral composition include oxidative catalysis decomposition of organic matters and reducing minerals,acid-catalyzed decomposition of carbonate minerals and feldspar minerals,hydrothermal catalysis induced fracture extension and cementation weakening induced fracture extension.SCW treatment converts harm into a benefit by reducing the intrusion of harmful substances into the shale formation,which will broaden the scope and scale of shale formation stimulation.展开更多
Accumulation of float coal dust(FCD)in underground mines is an explosion hazard that affects all underground coal mine workers.While this hazard is addressed by the application of rock dust,inadequate rock dusting pra...Accumulation of float coal dust(FCD)in underground mines is an explosion hazard that affects all underground coal mine workers.While this hazard is addressed by the application of rock dust,inadequate rock dusting practices can leave miners exposed to an explosion risk.Researchers at the National Institute for Occupational Safety and Health(NIOSH)have focused on developing a water curtain that removes FCD from the airstream,thereby reducing the buildup of FCD in mine airways.In this study,the number and spacing of the active sprays in the water curtain were varied to determine the optimal configuration to obtain peak knockdown efficiency(KE)while minimizing water consumption.展开更多
Based on the statistical data related to water pollution in recent years, this paper firstly describes in detail the current status of water pollution and water quality in rivers, lakes, reservoirs, groundwater and co...Based on the statistical data related to water pollution in recent years, this paper firstly describes in detail the current status of water pollution and water quality in rivers, lakes, reservoirs, groundwater and coastal waters in China, then makes a comprehensive analysis on future trends of water pollution in China. The authors hold that the economic power, technology level and management level have determinative influences on the current status and future trends of water pollution. At last, this paper discusses briefly the policies and measures for preventing and controlling water pollution in the light of the national conditions.展开更多
Low-permeability dense reservoirs,including micro-fractured reservoirs,are commonly characterized by high content of clay substances,high original water saturation,high sensitivity to invasive fluids,high capillary pr...Low-permeability dense reservoirs,including micro-fractured reservoirs,are commonly characterized by high content of clay substances,high original water saturation,high sensitivity to invasive fluids,high capillary pressure,complicated structure and anisotropic,high flow-resistance and micro pore throats etc,.Generally they also have lots of natural micro fractures,probably leading to stress sensibility.Main damaging factors in such reservoirs are water-sensibility and water-blocking caused by invasive fluids during drilling and production operations.Once damaged,formation permeability can rarely recovered.Numerous studies have shown that damaging extent of water-blocking ranges from 70% to 90%.Main damaging mechanisms and influencing factors of water-blocking were systematically analyzed.Also some feasible precaution or treating approaches of water-blocking were put forward.In a laboratory setting,a new multi-functional drilling fluid composed mainly of amphion polymer,sulfonation polymer,high effectively preventive water-blocking surfactants,ideal packing temporary bridging agents(TBA) and film-forming agents,etc.,were developed.New low-damage drilling fluids has many advantages,such as good rheological properties,excellent effectiveness of water-blocking prevention,good temporary plugging effect,low filtration and ultra-low permeability(API filtration≤5 mL,HTHP filtration≤10 mL,mud cake frictional coefficient≤0.14,permeability recovery>81%),can efficiently prevent or minimize damage,preserve natural formation and enhance comprehensive development-investment effect in TUHA Jurassic dense sandstone reservoir formation with low-permeability,the only one developing integrated condense gas field.Some references can be provided to similar reservoir formations.展开更多
目的了解2022年省、市、县疾控机构(Center for Disease Control and Prevention,CDC)对《生活饮用水卫生标准》(GB 5749-2006)中规定的106项指标的检测能力,分析省、市、县各指标检测能力不足的主要原因。方法收集2022年度全国各级CDC...目的了解2022年省、市、县疾控机构(Center for Disease Control and Prevention,CDC)对《生活饮用水卫生标准》(GB 5749-2006)中规定的106项指标的检测能力,分析省、市、县各指标检测能力不足的主要原因。方法收集2022年度全国各级CDC水质检测能力数据,对省级、地市级CDC的42项常规指标、64项非常规指标和对县级CDC的42项常规指标不具备检测能力的机构占比及不能检测的原因占比进行分析。结果省级CDC检测能力不足主要体现在总α放射性、总β放射性(4个省级,占比14%)和贾第鞭毛虫、隐孢子虫(6个省级,21%),主要原因均为设备配置不到位(100%),其次是无检测人员(50%~75%)。地市级CDC常规指标检测能力不足主要体现在总α放射性和总β放射性,占比均为47%;其次是消毒剂指标和消毒副产物指标(臭氧、总氯、ClO_(2)、甲醛、溴酸盐、亚氯酸盐和氯酸盐),占比为6%~22%,不具备检测能力的原因包括无设备、无标准品、无试剂和无检测人员;非常规指标中,除了氨氮(1%)外的63项指标不具备检测能力的机构占比均≥19%,其中贾第鞭毛虫和隐孢子虫不具备检测能力的机构占比最高(65%),主要原因为无设备(88%),其次为无检测人员(42%~43%)、无试剂(40%)和无标准品(38%);其余61项指标不能检测的原因为无设备、无标准品、无试剂和无检测人员(占比分别为60%~76%、45%~62%、42%~53%、51%~67%)。县级CDC常规指标中,放射性指标检测能力最弱(总α放射性和总β放射性,占比均为85%),其次是消毒剂指标和消毒副产物指标(臭氧、总氯、ClO_(2)、甲醛、溴酸盐、氯酸盐、亚氯酸盐、四氯化碳和三氯甲烷),不具备检测能力的主要原因以无设备(83%~94%)和无检测人员(53%~76%)为主。结论省、市、县CDC常规指标检测能力不足主要体现在放射性指标(省、市、县CDC),消毒剂指标(臭氧、总氯、ClO_(2))、消毒副产物指标(甲醛、溴酸盐、亚氯酸盐、氯酸盐)(市、县CDC),以及四氯化碳、三氯甲烷(县CDC);非常规指标中氨氮检测能力较好(省、市CDC),检测能力不足主要体现在贾第鞭毛虫和隐孢子虫(省、市CDC),及其他指标(市CDC)。检测能力不足的主要原因是设备配置不到位,今后应该重点从增配设备着手,增强水质检测能力。展开更多
基金Supported by Innovation Guidance and Technology-based Enterprise Cultivation Program of Yunnan Science and Technology Project(202304BP090027).
文摘This paper investigates the damage symptoms and occurrence regularity related to coffee leaf rust,and proposes a comprehensive prevention and control strategy grounded in the principle of prioritizing prevention and implementing integrated prevention and control.This strategy encompasses the cultivation of rust-resistant varieties,the implementation of agricultural practices,the application of chemical interventions,the utilization of hyperparasitic fungi,and the protection and utilization of natural enemies.The paper further outlines the necessary requirements for effective prevention and control,emphasizing the importance of enhancing responsibility implementation,fostering systematic prevention and control measures,enhancing guidance services,and increasing publicity and guidance.The aim is to offer technical guidance for the integrated prevention and control of coffee leaf rust in Yunnan Province.
基金This project was funded by Consulting Research Project of Chinese Academy of Engineering:Research on Innovative Development Strategy of Urban Safety Engineering(Project number:2020-02)。
文摘External disturbance is an important cause of underground pressure pipeline damage,which leads to accidents,and it is crucial to study the risk of damage caused by external disturbance and come up with proper prevention and control measures.We reviewed literature on risk identification of underground pressure pipelines damage due to external disturbance was conducted,and a list of risk factors was formed.Based on the list of risk factors,fault tree analysis was carried out on underground pressure pipelines damage caused by external disturbances,and risk prevention and control measures were proposed through the calculation of minimum cut sets,minimum path sets,and structural importance,in hopes of providing reference for the normal operation of underground pressure pipelines.
文摘[Objective] The aim was to develop prevention and control approaches of diseases and pests of Siraitia grosvenori. [Method] Long-term observation was con- ducted on cultivation methods of Siraitia grosvenori in the gardens in Longjiang Vil- lage of Yongfu County to conclude the prevention methods. [Result] Siraitia grosvenori yield can be reduced by nine diseases, such as root knot nematode dis- ease, and eight pests, such as Brachytrupes portentosus. [Conclusion] It would be effective for prevention of diseases and pests and guarantee quality and yield of Luohan guo to manage the gardens dominated by biological control and supple- mented by pesticide as per crop rotation.
基金the National Natural Science Foundation of China(No.50574061)
文摘Stress sensitivity and water blocking in fractured carbonate reservoir formations with low permeability were determined as the main potential damage mechanisms during drilling and completion operations in the ancient buried hill Ordovician reservoirs in the Tarim Basin. Geological structure, lithology, porosity, permeability and mineral components all affect the potential for formation damage. The experimental results showed that the permeability loss was 83.8%-98.6% caused by stress sensitivity, and was 27.9%-48.1% caused by water blocking. Based on the experimental results, several main conclusions concerning stress sensitivity can be drawn as follows： the lower the core permeability and the smaller the core fracture width, the higher the stress sensitivity. Also, stress sensitivity results in lag effect for both permeability recovery and fracture closure. Aimed at the mechanisms of formation damage, a modified low-damage mixed metal hydroxide （MMH） drilling fluid system was developed, which was mainly composed of low-fluorescence shale control agent, filtration control agent, lowfluorescence lubricant and surfactant. The results of experimental evaluation and field test showed that the newly-developed drilling fluid and engineering techniques provided could dramatically increase the return permeability （over 85%） of core samples. This drilling fluid had such advantages as good rheological and lubricating properties, high temperature stability, and low filtration rate （API filtration less than 5 ml after aging at 120 ℃ for 4 hours）. Therefore, fractured carbonate formations with low permeability could be protected effectively when drilling with the newly-developed drilling fluid. Meanwhile, field test showed that both penetration rate and bore stability were improved and the soaking time of the drilling fluid with formation was sharply shortened, indicating that the modified MMH drilling fluid could meet the requirements of drilling engineering and geology.
文摘The pathogenic characteristics of scab-anthracnoge of Fatsia japonica was introduced,and the infection cycle,occurrence regularity and main harmful symptoms of the disease were elaborated.Prevention is the main method to prevent scab-anthracnoge of F.japonica,and disease-free seedlings should be cultivated.Meantime,cultivation management should be strengthened to improve disease resistance of plant,and chemical agents must be timely sprayed in the early incidence stage,in order to achieve the purpose of comprehensive control.
文摘[ Objective ] The aim was to study the influence of filamentous algae on the process of water ecological purification. [ Method ] The occurrence mechanism of filamentous algae and its ecological system were summarized and analyzed. Considering the ecological purification in north- ern Jiangsu, the occurrence and prevention of filamentous algae in water, the method to prevent filamentous algae in polluted water was discussed. [ Result] The results showed that by measures of improving planting density, regular harvesting, and water flow state control before the filamentous algae blooming period, together with improving local pH value, light interference and ecological control during the blooming period, can effectively control the filamentous algae blooming. [ Condusion] The study of the happening mechanism of filamentous algae provided theoretical references and the technical basis in the work of filamentous algae prevention and control.
基金Supported by the National Natural Science Foundation of China,Science Foundation for Youths ( 41001165,40901133,30901163)
文摘The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.
文摘Since 2002,Hami City,Xinjiang Province,has implemented"construction project of rodent-free demonstration area".Artificial eagle frames are installed on the grassland to control rodent damage,receiving remarkable control effect.The rodent density in the treatment area is below the threshold of hazard.Moreover,the implementation of the project increases the grassland biomass and improves the vegetation coverage,receiving good economic,ecological and social benefits.
基金Sugar Crop Research System(CARS-170303)the Yunling Industry and Technology Leading Talent Training Program"Prevention and Control of Sugarcane Pests"(2018LJRC56)the Yunnan Province Agriculture Research System(YNGZTX-4-92)。
文摘Ceracris kiangsu Tsai is one of the most widely distributed forest pest.C.kiangsu has migrated from Laos to China this year,with many migration peaks and large population numbers.The main sources of C.kiangsu were from abroad and a small number of native insect sources exist.Most of the immigration sources were from Laos,and a small part originated from Vietnam.The frontier region of Yunnan Province is suitable for the growth of C.kiangsu.It is speculated that the migration frequency of the C.kiangsu from abroad may increase in recent years.In this paper,the typical morphological characteristics,life history,biological characteristics and prevention and control measures of C.kiangsu were summarized.Based on the characteristics of C.kiangsu,and combining actual sugarcane production condition in Yunnan sugarcane areas,we put forward prevention and control strategies and measures.It is suggested that Yunnan Sugarcane areas should pay close attention to the occurrence of C.kiangsu in neighboring countries,monitor the C.kiangsu population dynamics and update pest forecast information in time,and detect and control C.kiangsu in the early period,in order to effectively prevent C.kiangsu and ensure the safety of sugarcane production.
基金Supported by National Natural Science Foundation of China(51991361,52074327)Major Engineering Technology Field Test Project of CNPC(2020F-45)。
文摘By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.
文摘The shortage of water resources is severe in Beijing. The shortage of eco-environmental water and the sewage discharge over the environmental capacity are main bottlenecks that restrict the improvement of water environment. The reuse of wastewater could not only reduce the discharge of pollutants,but it could also increase the consumption of eco-environmental water. Therefore the reuse of wastewater is an important approach to improve the water environmental quality. Combined with the formulation process of Regulations of Beijing on Prevention and Control of Water Pollution,the current situations of prevention and control of water pollution in Beijing,the discharge of pollutant,water environmental quality,the population and economic development and water resources and so on were analyzed. And the bottlenecks that restricted the improvement of water environmental quality were found. And the necessity of solving the control of water pollution by reusing the wastewater and ensuring the consumption of eco-environmental water was analyzed from the perspective of the control of water pollution. And some legislative countermeasures were put forward,which provided new ideas for solving the problem of the prevention and control of water pollution and improving the water environmental quality. It was of important reference values for local governments（ especially water-deficient regions） to make relative polices or plans of water pollution control and water environmental protection.
文摘Water supply project of drawing from the Songhua River in central cities of Jilin is taken as research object.On the basis of analyzing project characteristics and natural conditions of the project area,site selection of waste slag yard of water diversion project and design of water and soil conservation measures are discussed.Rationality of site selection of waste slag yard and pertinence of prevention and control measures of water and soil loss in waste slag yard are analyzed,and comprehensive utilization of waste slag in large-scale production and construction projects is explored.
基金supported by the National Natural Science Foundation of China (No.41902154,No.51674209No.51604236)+3 种基金the Sichuan Youth Science and Technology Innovation Research Team Project (No.2021JDTDO017)the Sichuan Province Science and Technology Innovation Miaozi Engineering Cultivation Project (No.2021100)the China Scholarship Council (No.202109225004)。
文摘Shale gas reservoirs are unconventional tight gas reservoirs,in which horizontal wells and hydraulic fracturing are required to achieve commercial development.The fracture networks created by hydraulic fracturing can increase the drainage area extensively to enhance shale gas recovery.However,large volumes of fracturing fluid that is difficult to flow back to the surface and remained in the shale formation,will inevitably lead to damages of the shale formations and limit the effectiveness of stimulation.Supercritical water(SCW)treatment after hydraulic fracturing is a new method to enhance shale gas recovery by using appropriate heat treatment methods to the specific formation to convert the retained fracturing fluid into a supercritical state(at temperatures in excess of 373.946°C and pressures in excess of 22.064 MPa).An experiment was conducted to simulate the reaction between shale and SCW,and the capacity of SCW treatment to enhance the permeability of the shale was evaluated by measuring the response of the shale porosity and permeability on SCW treatment.The experimental results show that the shale porosity and permeability increase by 213.43%and 2198.37%,respectively.The pore structure alteration and permeability enhancement of the shale matrix were determined by analyzing the changes in pore structure and mineral composition after SCW treatment.The mechanisms that affect pore structure and mineral composition include oxidative catalysis decomposition of organic matters and reducing minerals,acid-catalyzed decomposition of carbonate minerals and feldspar minerals,hydrothermal catalysis induced fracture extension and cementation weakening induced fracture extension.SCW treatment converts harm into a benefit by reducing the intrusion of harmful substances into the shale formation,which will broaden the scope and scale of shale formation stimulation.
文摘Accumulation of float coal dust(FCD)in underground mines is an explosion hazard that affects all underground coal mine workers.While this hazard is addressed by the application of rock dust,inadequate rock dusting practices can leave miners exposed to an explosion risk.Researchers at the National Institute for Occupational Safety and Health(NIOSH)have focused on developing a water curtain that removes FCD from the airstream,thereby reducing the buildup of FCD in mine airways.In this study,the number and spacing of the active sprays in the water curtain were varied to determine the optimal configuration to obtain peak knockdown efficiency(KE)while minimizing water consumption.
文摘Based on the statistical data related to water pollution in recent years, this paper firstly describes in detail the current status of water pollution and water quality in rivers, lakes, reservoirs, groundwater and coastal waters in China, then makes a comprehensive analysis on future trends of water pollution in China. The authors hold that the economic power, technology level and management level have determinative influences on the current status and future trends of water pollution. At last, this paper discusses briefly the policies and measures for preventing and controlling water pollution in the light of the national conditions.
基金Project(50574061) supported by the National Natural Science Foundation of China
文摘Low-permeability dense reservoirs,including micro-fractured reservoirs,are commonly characterized by high content of clay substances,high original water saturation,high sensitivity to invasive fluids,high capillary pressure,complicated structure and anisotropic,high flow-resistance and micro pore throats etc,.Generally they also have lots of natural micro fractures,probably leading to stress sensibility.Main damaging factors in such reservoirs are water-sensibility and water-blocking caused by invasive fluids during drilling and production operations.Once damaged,formation permeability can rarely recovered.Numerous studies have shown that damaging extent of water-blocking ranges from 70% to 90%.Main damaging mechanisms and influencing factors of water-blocking were systematically analyzed.Also some feasible precaution or treating approaches of water-blocking were put forward.In a laboratory setting,a new multi-functional drilling fluid composed mainly of amphion polymer,sulfonation polymer,high effectively preventive water-blocking surfactants,ideal packing temporary bridging agents(TBA) and film-forming agents,etc.,were developed.New low-damage drilling fluids has many advantages,such as good rheological properties,excellent effectiveness of water-blocking prevention,good temporary plugging effect,low filtration and ultra-low permeability(API filtration≤5 mL,HTHP filtration≤10 mL,mud cake frictional coefficient≤0.14,permeability recovery>81%),can efficiently prevent or minimize damage,preserve natural formation and enhance comprehensive development-investment effect in TUHA Jurassic dense sandstone reservoir formation with low-permeability,the only one developing integrated condense gas field.Some references can be provided to similar reservoir formations.
文摘目的了解2022年省、市、县疾控机构(Center for Disease Control and Prevention,CDC)对《生活饮用水卫生标准》(GB 5749-2006)中规定的106项指标的检测能力,分析省、市、县各指标检测能力不足的主要原因。方法收集2022年度全国各级CDC水质检测能力数据,对省级、地市级CDC的42项常规指标、64项非常规指标和对县级CDC的42项常规指标不具备检测能力的机构占比及不能检测的原因占比进行分析。结果省级CDC检测能力不足主要体现在总α放射性、总β放射性(4个省级,占比14%)和贾第鞭毛虫、隐孢子虫(6个省级,21%),主要原因均为设备配置不到位(100%),其次是无检测人员(50%~75%)。地市级CDC常规指标检测能力不足主要体现在总α放射性和总β放射性,占比均为47%;其次是消毒剂指标和消毒副产物指标(臭氧、总氯、ClO_(2)、甲醛、溴酸盐、亚氯酸盐和氯酸盐),占比为6%~22%,不具备检测能力的原因包括无设备、无标准品、无试剂和无检测人员;非常规指标中,除了氨氮(1%)外的63项指标不具备检测能力的机构占比均≥19%,其中贾第鞭毛虫和隐孢子虫不具备检测能力的机构占比最高(65%),主要原因为无设备(88%),其次为无检测人员(42%~43%)、无试剂(40%)和无标准品(38%);其余61项指标不能检测的原因为无设备、无标准品、无试剂和无检测人员(占比分别为60%~76%、45%~62%、42%~53%、51%~67%)。县级CDC常规指标中,放射性指标检测能力最弱(总α放射性和总β放射性,占比均为85%),其次是消毒剂指标和消毒副产物指标(臭氧、总氯、ClO_(2)、甲醛、溴酸盐、氯酸盐、亚氯酸盐、四氯化碳和三氯甲烷),不具备检测能力的主要原因以无设备(83%~94%)和无检测人员(53%~76%)为主。结论省、市、县CDC常规指标检测能力不足主要体现在放射性指标(省、市、县CDC),消毒剂指标(臭氧、总氯、ClO_(2))、消毒副产物指标(甲醛、溴酸盐、亚氯酸盐、氯酸盐)(市、县CDC),以及四氯化碳、三氯甲烷(县CDC);非常规指标中氨氮检测能力较好(省、市CDC),检测能力不足主要体现在贾第鞭毛虫和隐孢子虫(省、市CDC),及其他指标(市CDC)。检测能力不足的主要原因是设备配置不到位,今后应该重点从增配设备着手,增强水质检测能力。
