Upon the basis of comprehensive survey on the bio-resources of Zhengzhou Yellow River Wetland Nature Reserve,we analyzed the relationship between wetland ecology and bio-resource protection,the problems encountering w...Upon the basis of comprehensive survey on the bio-resources of Zhengzhou Yellow River Wetland Nature Reserve,we analyzed the relationship between wetland ecology and bio-resource protection,the problems encountering wetland development and protection,and further put forward corresponding protective measures.展开更多
Firstly, characteristics of coastal wind farms were analyzed, and then lightning damage to coastal wind farms was discussed, finally main lightning protection measures were put forward from aspects of turbine blades, ...Firstly, characteristics of coastal wind farms were analyzed, and then lightning damage to coastal wind farms was discussed, finally main lightning protection measures were put forward from aspects of turbine blades, engine rooms and overvoltage protection. Besides conventional light- ning protection technology, local lightning protection, pre-discharge and lightning motoring and early warning techniques should be used to protect coastal wind farms against lightning.展开更多
Introduction Lightning can cause great destruction. According to the record in the northern China, more than 150 lightning strokes occur on a power system annually. High voltage (millions of volts) and large current (...Introduction Lightning can cause great destruction. According to the record in the northern China, more than 150 lightning strokes occur on a power system annually. High voltage (millions of volts) and large current (hundreds of -kA) associated with lightning, will damage property and even kill people and livestocks. It will be very dangerous if a lightning stroke strikes oil depot of power plant or substation. In addition, the high voltage induced by the electrostatic charge generated due to oil flowing will probably cause damage unless the electrification has been limited and drained off.展开更多
Under the influence of special terrain and climatic conditions,lightning weather in Ulanqab City is more frequent from June to August,and lightning disaster has become one of the important tasks of disaster prevention...Under the influence of special terrain and climatic conditions,lightning weather in Ulanqab City is more frequent from June to August,and lightning disaster has become one of the important tasks of disaster prevention and mitigation.In this paper,based on the characteristics of lightning weather in Ulanqab City,the impact of lightning disaster on the city was analyzed,and lightning protection measures,such as strengthening supervision of lightning protection safety,establishing a long-term lightning protection mechanism,doing a good job in lightning protection construction and detection in key places,and further improving public awareness of lightning protection,were put forward to reduce and avoid urban lightning disasters as much as possible and ensure urban safety.展开更多
The structural design and protective methods for the 100 kW shoreline wave power station in China are described in detail. The proper structural type is designed for effective minimization of wave loads and bending st...The structural design and protective methods for the 100 kW shoreline wave power station in China are described in detail. The proper structural type is designed for effective minimization of wave loads and bending stress. Various protective devices are adopted to protect the station in the extreme conditions against excessive power of airflow, excessive torsion of the shaft, over-pressure of the chamber, over-speed of rotation, power failure, and so on. It turns out that the structural design and protective methods for the 100 kW shoreline wave power station are successful.展开更多
Platforms facilitate information exchange,streamline resources,and reduce production and management costs for companies.However,some viral information may invade and steal company resources,or lead to information leak...Platforms facilitate information exchange,streamline resources,and reduce production and management costs for companies.However,some viral information may invade and steal company resources,or lead to information leakage.For this reason,this paper discusses the standards for cybersecurity protection,examines the current state of cybersecurity management and the risks faced by cloud platforms,expands the time and space for training on cloud platforms,and provides recommendations for measuring the level of cybersecurity protection within cloud platforms in order to build a solid foundation for them.展开更多
Based on the theory of coordinating action of building ground, foundation and structure, this paper presents a modified method for calculating additional stresses on buildings in mining areas by considering the joint ...Based on the theory of coordinating action of building ground, foundation and structure, this paper presents a modified method for calculating additional stresses on buildings in mining areas by considering the joint effect of cur- vature deformation and horizontal deformation on buildings. It points out that for buildings over the coal pillar, it is ad- visable to soften the intermediate ground of buildings when they are affected by mining. For buildings over the goaf, it is preferable to soften the ground at both ends of buildings. In order to enhance the ability of a building to resist tensile deformation, the key measure is to reinforce the bottom foundation of the building. In addition, the concept of “angle of break of building” is proposed. It is because of this angle that the protecting coal pillar is left, which is a better solution than prevailing solutions The findings provide a more scientific basis for mining under buildings.展开更多
Objective There are evidences that heat wave events cause deaths and emergency cases. This article used the contingent valuation method to find the willingness to pay for the protective measures and investigated the f...Objective There are evidences that heat wave events cause deaths and emergency cases. This article used the contingent valuation method to find the willingness to pay for the protective measures and investigated the factors that influence the willingness to pay. Methods A cross-sectional face-to-face household survey was completed by 637 urban long-term residents and 591 rural long-term residents aged 15-79 in Beijing, China. Binary logistic regression was used to identify factors that influenced the payment rate or payment amount for the protective measures, including independent variables for district, gender, age, education, income, air conditioner ownership, heat wave experience, and chronic non-communicable disease. Results The payment rate was 41.1% for protective measures provided by the government and 39.5% by measures provided by the market. Most of the respondents were willing to pay 40 CNY per capita annually for measures provided by the government or the market. The factors influencing willingness to pay were district, gender, income, air conditioner ownership, heat wave experience, and chronic non-communicable disease. Conclusion Protective measures for heat waves need to be provided immediately. More attention should be paid to the situation of vulnerable groups, such as people who live in urban areas, those without air conditioning, and those who have experienced a heat wave in the past.展开更多
In order to better promote the restoration and sustainable development of the natural ecological environment,it is necessary to study the wetland system as an important part of the ecosystem,put forward some common pr...In order to better promote the restoration and sustainable development of the natural ecological environment,it is necessary to study the wetland system as an important part of the ecosystem,put forward some common problems faced by wetland nature reserves,and propose relevant solutions based on the problems.This paper describes the relevant theoretical basis for the ecological environment protection of the wetland nature reserves,the problems faced,and the relevant solutions as reference for relevant personnel.展开更多
Aiming at utilization status of arable land resources in Anshun City,a Karst area,quantitative and qualitative analyses were performed from the viewpoints of quality,quantity and benefits of arable land.And the benefi...Aiming at utilization status of arable land resources in Anshun City,a Karst area,quantitative and qualitative analyses were performed from the viewpoints of quality,quantity and benefits of arable land.And the benefits of arable land were analyzed with multiple linear regression.Finally,the sustainable utilization of arable land resources was discussed,and several protection measures were pointed out.展开更多
Dunhuang Mogao Grottoes is one of the largest art treasures in the world.She has a large number of murals,sculptures,beautiful and vivid;There are precious Buddhist scriptures,documents,noble and elegant.Spanning more...Dunhuang Mogao Grottoes is one of the largest art treasures in the world.She has a large number of murals,sculptures,beautiful and vivid;There are precious Buddhist scriptures,documents,noble and elegant.Spanning more than 1,600 years,the Mogao Grottoes show the world the extensive and profound Chinese culture with a long history.But over time,the murals in the Mogao Grottoes have also changed a lot.Thousands of years of wind and rain erosion,changes in the surrounding environment,and the influence of various biological communities have caused serious color changes and fading of murals in Mogao Grottoes.To slow down the color change of Dunhuang frescoes,protection measures should be taken from the perspective of ecological microorganisms.At present,Cladosporium,Planococcus,Phoma,Chaetomium,and other strains have caused serious discoloration or discoloration of murals to a certain extent.This paper studies the main color of Dunhuang frescoes,red,and summarizes the discoloration factors and mechanism of red lead.On this level,one should try to keep the murals and control the indoor temperature.Humidity,people,and other factors slow the fading of the murals.But these are often insufficient to protect the integrity of the murals,so we have conducted a review of the literature to provide an updated overview of the available evidence on the subject.展开更多
Campus network provides a critical stage to student service and campus administration,which assumes a paramount part in the strategy of‘Rejuvenating the Country through Science and Education’and‘Revitalizing China ...Campus network provides a critical stage to student service and campus administration,which assumes a paramount part in the strategy of‘Rejuvenating the Country through Science and Education’and‘Revitalizing China through Talented Persons’.However,with the rapid development and continuous expansion of campus network,network security needs to be an essential issue that could not be overlooked in campus network construction.In order to ensure the normal operation of various functions of the campus network,the security risk level of the campus network is supposed to be controlled within a reasonable range at any moment.Through literature research,theory analysis and other methods,this paper systematically combs the research on campus network security at home and abroad,analyzing and researching the campus network security issues from a theoretical perspective.A series of efficient solutions accordingly were also put forward.展开更多
In this paper,a theoretical solution of vertical buckling is proposed with regard to the typical initial imperfection cases of submarine pipelines.Analytical tools are applied to predicting the occurrence and conseque...In this paper,a theoretical solution of vertical buckling is proposed with regard to the typical initial imperfection cases of submarine pipelines.Analytical tools are applied to predicting the occurrence and consequence of inservice buckling of a buried heated pipeline in Bohai Gulf.An evaluation is performed to ensure the pipeline structural integrity during operation under loading conditions.Different protection measures are proposed and their validities are analyzed.Analyses show that for the same magnitude of initial imperfection,the upheaval buckling of pipeline with isolated prop model is the most likely to occur.The empathetic model represents a special sub-case of continuous prop model,and the calculated buckle temperature is between the first stage and the second stage of post-upheaval buckling of continuous prop model.And the larger the initial imperfection,the less the axial force required for the upheaval buckling.Meanwhile,it can be seen that a peak point appears on the curves of temperature difference against buckling amplitude for small initial imperfection.Besides,trenching-burial is one kind of protection measures preventing the pipeline from thermal upheaval.The covered depth-to-diameter ratio depends on the design conditions and subsoil properties.For the given pipeline in this paper,the covered depth-to-diameter ratio is recommended to be 5.展开更多
To fit in with the developing requirement of int and communication of protective relays, a protection egrated functions of protection measurement, control measurement and control system based on DeviceNet fieldbus is ...To fit in with the developing requirement of int and communication of protective relays, a protection egrated functions of protection measurement, control measurement and control system based on DeviceNet fieldbus is designed. The communication mechanism of DeviceNet is studied and data trigger modes, communication connection, message types and other key technologies are analyzed. The object modeling and device description of the device are realized too. Results of network test, dynamic simulation and test in the field indicate that this system can accomplish all the communication tasks in real time and can make precise response to every kind of faults of the motor, transformer, line and capacitor. Moreover, this system has higher measurement precision and better control capability.展开更多
[ Objective] The aim was to study the biodiversity and its protection measures in Qinling. [Method] The current situation and protection measures of the biodiversity in Qinling area were reviewed by the perspective of...[ Objective] The aim was to study the biodiversity and its protection measures in Qinling. [Method] The current situation and protection measures of the biodiversity in Qinling area were reviewed by the perspective of eco-safety and the eco-value. [Result] Qinling is the natural gene bank for the study of the origin and development of living beings. Forest ecological system is the main body, with many ecological systems and com- plete vertical spectrometer. The plants have various varieties, complicated components, rare species, rich special plant and old heritance. There were 722 species of vertebrates, including 162 species in 16 families of 7 orders of fish, 26 species in 8 families of 2 orders of amphibian, 44 species in 8 families of 2 orders of reptiles, 373 species in 53 families of 17 orders of birds, and 117 species in 27 families of 7 orders of animals. The num- ber of order, family and species of vertebrates was 70%, 53.04% and 22.06%. It was suggested to formulate policy promoting biodiversity protec- tion and sustainable development, building natural protection net system to protect biodiversity in Qinling. [ Coecluslon] The study provided theoreti- cal basis for the protection of biodiversity in Qinling area.展开更多
Natural gas should be heated and throttled for the purpose of purification and transportation at the first gas production factory of the Changqing field. The safe use and heat-transfer efficiency of a heating-furnace ...Natural gas should be heated and throttled for the purpose of purification and transportation at the first gas production factory of the Changqing field. The safe use and heat-transfer efficiency of a heating-furnace affect the safe and smooth production of natural gas directly. At gas collecting stations now, no measures of anticorrosion have been adopted in heating furnaces which erode and scale badly. In order to solve the corrosive problem of heating-furnaces, prolong operating life of heating-furnaces, assure safe and smooth production of natural gas, the mechanism and influencing factors of corrosion of the heating-furnace were analyzed and some corresponding measures were brought forward based on a field investigation of usage behavior and present operational status of heating-furnaces at the first gas production factory. The results show that the corrosive ion and soluble CO2 and O2 in water erode metal badly at the condition of being heated. Corrosion of a heating-furnace are mostly oxygen corrosion, corrosive ion corrosion, acid corrosion, iron encrustation corrosion, dry and wet interface corrosion, caustic corrosion, etc; The influencing factors of corrosion mainly include soluble O2 and CO2 in water, pH value, heat loading, corrosive ion, soluble solid (salinity) and non-flowing character of water, etc.展开更多
BACKGROUND Coronavirus disease 2019(COVID-19)significantly affected endoscopy practice,as gastrointestinal endoscopy is considered a risky procedure for transmission of infection to patients and personnel of endoscopy...BACKGROUND Coronavirus disease 2019(COVID-19)significantly affected endoscopy practice,as gastrointestinal endoscopy is considered a risky procedure for transmission of infection to patients and personnel of endoscopy units(PEU).AIM To assess the impact of COVID-19 on endoscopy during the first European lockdown(March-May 2020).METHODS Patients undergoing endoscopy in nine endoscopy units across six European countries during the period of the first European lockdown for COVID-19(March-May 2020)were included.Prior to the endoscopy procedure,participants were stratified as low-or high-risk for potential COVID-19 infection according to the European Society of Gastrointestinal Endoscopy(ESGE)and the European Society of Gastroenterology and Endoscopy Nurses and Associates(ESGENA)joint statement,and contacted 7-14 d later to assess COVID-19 infection status.PEU were questioned regarding COVID-19 symptoms and/or infection via questionnaire,while information regarding hospitalizations,intensive care unitadmissions and COVID-19-related deaths were collected.The number of weekly endoscopies at each center during the lockdown period was also recorded.RESULTS A total of 1267 endoscopies were performed in 1222 individuals across nine European endoscopy departments in six countries.Eighty-seven(7%)were excluded because of initial positive testing.Of the 1135 pre-endoscopy low risk or polymerase chain reaction negative for COVID-19,254(22.4%)were tested post endoscopy and 8 were eventually found positive,resulting in an infection rate of 0.7%[95%CI:0.2-0.12].The majority(6 of the 8 patients,75%)had undergone esophagogastroduodenoscopy.Of the 163 PEU,5[3%;(95%CI:0.4-5.7)]tested positive during the study period.A decrease of 68.7%(95%CI:64.8-72.7)in the number of weekly endoscopies was recorded in all centers after March 2020.All centers implemented appropriate personal protective measures(PPM)from the initial phases of the lockdown.CONCLUSION COVID-19 transmission in endoscopy units is highly unlikely in a lockdown setting,provided endoscopies are restricted to emergency cases and PPM are implemented.展开更多
Aiming at acute characteristics of flammability,explosibility,causticity and leakiness of high sour natural gas,giving full consideration to local natural conditions in Sichuan Province and starting with purification ...Aiming at acute characteristics of flammability,explosibility,causticity and leakiness of high sour natural gas,giving full consideration to local natural conditions in Sichuan Province and starting with purification process,the paper analyzed process configurations,energy utilization and conservation,safety and environment protection measures. The integrated technology and engineering scheme for high sour natural gas purification was established and successfully used in industrial application.展开更多
During the last decade, large rockfalls occurred on the steep limestone slopes along the Adriatic Coast of Croatia, causing injury to people and serious damage to buildings and traffic facilities. The rockfalls along ...During the last decade, large rockfalls occurred on the steep limestone slopes along the Adriatic Coast of Croatia, causing injury to people and serious damage to buildings and traffic facilities. The rockfalls along the limestone slopes were caused by unfavorable characteristics of the rock mass, weathering in combination with heavy rainfall and artificial influences during highway construction. Rockfall protection projects were conducted to protect human lives and facilities from future rockfalls. The rockfall protection program started with rockfall hazard analyses to identify the potential of rockfalls to occur and the potential consequences. At the locations of hazards where related risks were determined, detailed field investigations were conducted. Based on the indentified characteristics of potentially unstable rock masses, analyses of movement and resulting pathways were conducted. The trajectories, impact energy and the height of bouncing are dependent on slope geometry, slope surface roughness and rockfall block characteristics. Two protection measure approaches were adopted: prevention of rockfalls by removing potentially unstable rock mass or installation of rock mass support systems and suspending running rockfall masses with rockfall protection barriers. In this paper, rockfall hazard determination, rockfall analyses and rockfall protection designs for rockfall protection systems at selected locations on the limestone slopes along the Adriatic coast of Croatia are presented.展开更多
The outbreak of COVID-19 in Wuhan began to spread rapidly in December 2019.It is highly infectious and widely spread.This article summarizes the care experience of one critically ill COVID‑19 patient,including the str...The outbreak of COVID-19 in Wuhan began to spread rapidly in December 2019.It is highly infectious and widely spread.This article summarizes the care experience of one critically ill COVID‑19 patient,including the strict implementation of protective measures,avoiding infection,precautions for high‑risk caring of tracheal intubation,giving psychological care,improving the coordination,the importance of vital signs,food intake and excretion,and how to reduce the risk of infection during sample collection,as well as strengthening discharge guidance.展开更多
基金Supported by Program for Decision Making of Henan Province(B339)Key R&D Program of Zhengzhou Science and Technology Bureau(10PTGN449-5)~~
文摘Upon the basis of comprehensive survey on the bio-resources of Zhengzhou Yellow River Wetland Nature Reserve,we analyzed the relationship between wetland ecology and bio-resource protection,the problems encountering wetland development and protection,and further put forward corresponding protective measures.
基金Supported by the Integration and Application Project of Meteorological Key Technologies of China Meteorological Administration(Risk Assessment of Thunder and Lightning Disaster and Application of Key Lightning Protection Technologies in Wind Farms)
文摘Firstly, characteristics of coastal wind farms were analyzed, and then lightning damage to coastal wind farms was discussed, finally main lightning protection measures were put forward from aspects of turbine blades, engine rooms and overvoltage protection. Besides conventional light- ning protection technology, local lightning protection, pre-discharge and lightning motoring and early warning techniques should be used to protect coastal wind farms against lightning.
文摘Introduction Lightning can cause great destruction. According to the record in the northern China, more than 150 lightning strokes occur on a power system annually. High voltage (millions of volts) and large current (hundreds of -kA) associated with lightning, will damage property and even kill people and livestocks. It will be very dangerous if a lightning stroke strikes oil depot of power plant or substation. In addition, the high voltage induced by the electrostatic charge generated due to oil flowing will probably cause damage unless the electrification has been limited and drained off.
文摘Under the influence of special terrain and climatic conditions,lightning weather in Ulanqab City is more frequent from June to August,and lightning disaster has become one of the important tasks of disaster prevention and mitigation.In this paper,based on the characteristics of lightning weather in Ulanqab City,the impact of lightning disaster on the city was analyzed,and lightning protection measures,such as strengthening supervision of lightning protection safety,establishing a long-term lightning protection mechanism,doing a good job in lightning protection construction and detection in key places,and further improving public awareness of lightning protection,were put forward to reduce and avoid urban lightning disasters as much as possible and ensure urban safety.
文摘The structural design and protective methods for the 100 kW shoreline wave power station in China are described in detail. The proper structural type is designed for effective minimization of wave loads and bending stress. Various protective devices are adopted to protect the station in the extreme conditions against excessive power of airflow, excessive torsion of the shaft, over-pressure of the chamber, over-speed of rotation, power failure, and so on. It turns out that the structural design and protective methods for the 100 kW shoreline wave power station are successful.
文摘Platforms facilitate information exchange,streamline resources,and reduce production and management costs for companies.However,some viral information may invade and steal company resources,or lead to information leakage.For this reason,this paper discusses the standards for cybersecurity protection,examines the current state of cybersecurity management and the risks faced by cloud platforms,expands the time and space for training on cloud platforms,and provides recommendations for measuring the level of cybersecurity protection within cloud platforms in order to build a solid foundation for them.
基金Project 50474064 supported by the National Natural Science Foundation of China
文摘Based on the theory of coordinating action of building ground, foundation and structure, this paper presents a modified method for calculating additional stresses on buildings in mining areas by considering the joint effect of cur- vature deformation and horizontal deformation on buildings. It points out that for buildings over the coal pillar, it is ad- visable to soften the intermediate ground of buildings when they are affected by mining. For buildings over the goaf, it is preferable to soften the ground at both ends of buildings. In order to enhance the ability of a building to resist tensile deformation, the key measure is to reinforce the bottom foundation of the building. In addition, the concept of “angle of break of building” is proposed. It is because of this angle that the protecting coal pillar is left, which is a better solution than prevailing solutions The findings provide a more scientific basis for mining under buildings.
基金supported by National Natural Science Foundation of China(Project Number:21277135,91543111)Natural Science Foundation of Beijing Municipality(Project Number:8132048)
文摘Objective There are evidences that heat wave events cause deaths and emergency cases. This article used the contingent valuation method to find the willingness to pay for the protective measures and investigated the factors that influence the willingness to pay. Methods A cross-sectional face-to-face household survey was completed by 637 urban long-term residents and 591 rural long-term residents aged 15-79 in Beijing, China. Binary logistic regression was used to identify factors that influenced the payment rate or payment amount for the protective measures, including independent variables for district, gender, age, education, income, air conditioner ownership, heat wave experience, and chronic non-communicable disease. Results The payment rate was 41.1% for protective measures provided by the government and 39.5% by measures provided by the market. Most of the respondents were willing to pay 40 CNY per capita annually for measures provided by the government or the market. The factors influencing willingness to pay were district, gender, income, air conditioner ownership, heat wave experience, and chronic non-communicable disease. Conclusion Protective measures for heat waves need to be provided immediately. More attention should be paid to the situation of vulnerable groups, such as people who live in urban areas, those without air conditioning, and those who have experienced a heat wave in the past.
基金Heilongjiang Province Cold Region Wetland Ecological and Environmental Research Key Laboratory Open Project in 2019(PrqjectNo.:201907)。
文摘In order to better promote the restoration and sustainable development of the natural ecological environment,it is necessary to study the wetland system as an important part of the ecosystem,put forward some common problems faced by wetland nature reserves,and propose relevant solutions based on the problems.This paper describes the relevant theoretical basis for the ecological environment protection of the wetland nature reserves,the problems faced,and the relevant solutions as reference for relevant personnel.
基金Supported by Natural Science Youth Project of Education Department of Guizhou Province (Guizhou Education Science 2008085)
文摘Aiming at utilization status of arable land resources in Anshun City,a Karst area,quantitative and qualitative analyses were performed from the viewpoints of quality,quantity and benefits of arable land.And the benefits of arable land were analyzed with multiple linear regression.Finally,the sustainable utilization of arable land resources was discussed,and several protection measures were pointed out.
文摘Dunhuang Mogao Grottoes is one of the largest art treasures in the world.She has a large number of murals,sculptures,beautiful and vivid;There are precious Buddhist scriptures,documents,noble and elegant.Spanning more than 1,600 years,the Mogao Grottoes show the world the extensive and profound Chinese culture with a long history.But over time,the murals in the Mogao Grottoes have also changed a lot.Thousands of years of wind and rain erosion,changes in the surrounding environment,and the influence of various biological communities have caused serious color changes and fading of murals in Mogao Grottoes.To slow down the color change of Dunhuang frescoes,protection measures should be taken from the perspective of ecological microorganisms.At present,Cladosporium,Planococcus,Phoma,Chaetomium,and other strains have caused serious discoloration or discoloration of murals to a certain extent.This paper studies the main color of Dunhuang frescoes,red,and summarizes the discoloration factors and mechanism of red lead.On this level,one should try to keep the murals and control the indoor temperature.Humidity,people,and other factors slow the fading of the murals.But these are often insufficient to protect the integrity of the murals,so we have conducted a review of the literature to provide an updated overview of the available evidence on the subject.
基金sponsored by the JSPIGKZ Project (No.2911121110)Innovative and Entrepreneurial Doctor of Jiangsu Province (No.JSSCBS20210598)+1 种基金Jiangsu Provincial University Nature Science Foundation Project (No.2020KX007Z)Jiangsu Provincial Science and Technology Research Project (No.20KJB413002)。
文摘Campus network provides a critical stage to student service and campus administration,which assumes a paramount part in the strategy of‘Rejuvenating the Country through Science and Education’and‘Revitalizing China through Talented Persons’.However,with the rapid development and continuous expansion of campus network,network security needs to be an essential issue that could not be overlooked in campus network construction.In order to ensure the normal operation of various functions of the campus network,the security risk level of the campus network is supposed to be controlled within a reasonable range at any moment.Through literature research,theory analysis and other methods,this paper systematically combs the research on campus network security at home and abroad,analyzing and researching the campus network security issues from a theoretical perspective.A series of efficient solutions accordingly were also put forward.
基金Supported by National Natural Science Foundation of China (No.40776055)
文摘In this paper,a theoretical solution of vertical buckling is proposed with regard to the typical initial imperfection cases of submarine pipelines.Analytical tools are applied to predicting the occurrence and consequence of inservice buckling of a buried heated pipeline in Bohai Gulf.An evaluation is performed to ensure the pipeline structural integrity during operation under loading conditions.Different protection measures are proposed and their validities are analyzed.Analyses show that for the same magnitude of initial imperfection,the upheaval buckling of pipeline with isolated prop model is the most likely to occur.The empathetic model represents a special sub-case of continuous prop model,and the calculated buckle temperature is between the first stage and the second stage of post-upheaval buckling of continuous prop model.And the larger the initial imperfection,the less the axial force required for the upheaval buckling.Meanwhile,it can be seen that a peak point appears on the curves of temperature difference against buckling amplitude for small initial imperfection.Besides,trenching-burial is one kind of protection measures preventing the pipeline from thermal upheaval.The covered depth-to-diameter ratio depends on the design conditions and subsoil properties.For the given pipeline in this paper,the covered depth-to-diameter ratio is recommended to be 5.
文摘To fit in with the developing requirement of int and communication of protective relays, a protection egrated functions of protection measurement, control measurement and control system based on DeviceNet fieldbus is designed. The communication mechanism of DeviceNet is studied and data trigger modes, communication connection, message types and other key technologies are analyzed. The object modeling and device description of the device are realized too. Results of network test, dynamic simulation and test in the field indicate that this system can accomplish all the communication tasks in real time and can make precise response to every kind of faults of the motor, transformer, line and capacitor. Moreover, this system has higher measurement precision and better control capability.
基金Supported by Opening Fund of State Key Laboratory of Loess and Quaternary Geology
文摘[ Objective] The aim was to study the biodiversity and its protection measures in Qinling. [Method] The current situation and protection measures of the biodiversity in Qinling area were reviewed by the perspective of eco-safety and the eco-value. [Result] Qinling is the natural gene bank for the study of the origin and development of living beings. Forest ecological system is the main body, with many ecological systems and com- plete vertical spectrometer. The plants have various varieties, complicated components, rare species, rich special plant and old heritance. There were 722 species of vertebrates, including 162 species in 16 families of 7 orders of fish, 26 species in 8 families of 2 orders of amphibian, 44 species in 8 families of 2 orders of reptiles, 373 species in 53 families of 17 orders of birds, and 117 species in 27 families of 7 orders of animals. The num- ber of order, family and species of vertebrates was 70%, 53.04% and 22.06%. It was suggested to formulate policy promoting biodiversity protec- tion and sustainable development, building natural protection net system to protect biodiversity in Qinling. [ Coecluslon] The study provided theoreti- cal basis for the protection of biodiversity in Qinling area.
文摘Natural gas should be heated and throttled for the purpose of purification and transportation at the first gas production factory of the Changqing field. The safe use and heat-transfer efficiency of a heating-furnace affect the safe and smooth production of natural gas directly. At gas collecting stations now, no measures of anticorrosion have been adopted in heating furnaces which erode and scale badly. In order to solve the corrosive problem of heating-furnaces, prolong operating life of heating-furnaces, assure safe and smooth production of natural gas, the mechanism and influencing factors of corrosion of the heating-furnace were analyzed and some corresponding measures were brought forward based on a field investigation of usage behavior and present operational status of heating-furnaces at the first gas production factory. The results show that the corrosive ion and soluble CO2 and O2 in water erode metal badly at the condition of being heated. Corrosion of a heating-furnace are mostly oxygen corrosion, corrosive ion corrosion, acid corrosion, iron encrustation corrosion, dry and wet interface corrosion, caustic corrosion, etc; The influencing factors of corrosion mainly include soluble O2 and CO2 in water, pH value, heat loading, corrosive ion, soluble solid (salinity) and non-flowing character of water, etc.
文摘BACKGROUND Coronavirus disease 2019(COVID-19)significantly affected endoscopy practice,as gastrointestinal endoscopy is considered a risky procedure for transmission of infection to patients and personnel of endoscopy units(PEU).AIM To assess the impact of COVID-19 on endoscopy during the first European lockdown(March-May 2020).METHODS Patients undergoing endoscopy in nine endoscopy units across six European countries during the period of the first European lockdown for COVID-19(March-May 2020)were included.Prior to the endoscopy procedure,participants were stratified as low-or high-risk for potential COVID-19 infection according to the European Society of Gastrointestinal Endoscopy(ESGE)and the European Society of Gastroenterology and Endoscopy Nurses and Associates(ESGENA)joint statement,and contacted 7-14 d later to assess COVID-19 infection status.PEU were questioned regarding COVID-19 symptoms and/or infection via questionnaire,while information regarding hospitalizations,intensive care unitadmissions and COVID-19-related deaths were collected.The number of weekly endoscopies at each center during the lockdown period was also recorded.RESULTS A total of 1267 endoscopies were performed in 1222 individuals across nine European endoscopy departments in six countries.Eighty-seven(7%)were excluded because of initial positive testing.Of the 1135 pre-endoscopy low risk or polymerase chain reaction negative for COVID-19,254(22.4%)were tested post endoscopy and 8 were eventually found positive,resulting in an infection rate of 0.7%[95%CI:0.2-0.12].The majority(6 of the 8 patients,75%)had undergone esophagogastroduodenoscopy.Of the 163 PEU,5[3%;(95%CI:0.4-5.7)]tested positive during the study period.A decrease of 68.7%(95%CI:64.8-72.7)in the number of weekly endoscopies was recorded in all centers after March 2020.All centers implemented appropriate personal protective measures(PPM)from the initial phases of the lockdown.CONCLUSION COVID-19 transmission in endoscopy units is highly unlikely in a lockdown setting,provided endoscopies are restricted to emergency cases and PPM are implemented.
文摘Aiming at acute characteristics of flammability,explosibility,causticity and leakiness of high sour natural gas,giving full consideration to local natural conditions in Sichuan Province and starting with purification process,the paper analyzed process configurations,energy utilization and conservation,safety and environment protection measures. The integrated technology and engineering scheme for high sour natural gas purification was established and successfully used in industrial application.
文摘During the last decade, large rockfalls occurred on the steep limestone slopes along the Adriatic Coast of Croatia, causing injury to people and serious damage to buildings and traffic facilities. The rockfalls along the limestone slopes were caused by unfavorable characteristics of the rock mass, weathering in combination with heavy rainfall and artificial influences during highway construction. Rockfall protection projects were conducted to protect human lives and facilities from future rockfalls. The rockfall protection program started with rockfall hazard analyses to identify the potential of rockfalls to occur and the potential consequences. At the locations of hazards where related risks were determined, detailed field investigations were conducted. Based on the indentified characteristics of potentially unstable rock masses, analyses of movement and resulting pathways were conducted. The trajectories, impact energy and the height of bouncing are dependent on slope geometry, slope surface roughness and rockfall block characteristics. Two protection measure approaches were adopted: prevention of rockfalls by removing potentially unstable rock mass or installation of rock mass support systems and suspending running rockfall masses with rockfall protection barriers. In this paper, rockfall hazard determination, rockfall analyses and rockfall protection designs for rockfall protection systems at selected locations on the limestone slopes along the Adriatic coast of Croatia are presented.
基金Financial support and sponsorship This work was supported the Lanzhou city science and technology project‑‑Psychological Intervention Study of COVID‑19 Isolation and Protection Medical Workers by Mindfulness Behavior Delivery isolation and protection medical staff.
文摘The outbreak of COVID-19 in Wuhan began to spread rapidly in December 2019.It is highly infectious and widely spread.This article summarizes the care experience of one critically ill COVID‑19 patient,including the strict implementation of protective measures,avoiding infection,precautions for high‑risk caring of tracheal intubation,giving psychological care,improving the coordination,the importance of vital signs,food intake and excretion,and how to reduce the risk of infection during sample collection,as well as strengthening discharge guidance.