Various industries today rely on the support of electromechanical equipment,expanding its scope of application and leading to an increase in electromechanical installation projects.However,due to the high level of exp...Various industries today rely on the support of electromechanical equipment,expanding its scope of application and leading to an increase in electromechanical installation projects.However,due to the high level of expertise required and the potential risks involved,it is crucial to emphasize safety management during construction.This paper delves into the significance of construction safety management for electromechanical installation projects,identifies common problems encountered during construction,and proposes solutions.This analysis aims to provide relevant personnel with essential guidance and references for managing electromechanical installation projects safely.展开更多
BACKGROUND Lack of mobilization and prolonged stay in the intensive care unit(ICU)are major factors resulting in the development of ICU-acquired muscle weakness(ICUAW).ICUAW is a type of skeletal muscle dysfunction an...BACKGROUND Lack of mobilization and prolonged stay in the intensive care unit(ICU)are major factors resulting in the development of ICU-acquired muscle weakness(ICUAW).ICUAW is a type of skeletal muscle dysfunction and a common complication of patients after cardiac surgery,and may be a risk factor for prolonged duration of mechanical ventilation,associated with a higher risk of readmission and higher mortality.Early mobilization in the ICU after cardiac surgery has been found to be low with a significant trend to increase over ICU stay and is also associated with a reduced duration of mechanical ventilation and ICU length of stay.Neuromuscular electrical stimulation(NMES)is an alternative modality of exercise in patients with muscle weakness.A major advantage of NMES is that it can be applied even in sedated patients in the ICU,a fact that might enhance early mobilization in these patients.AIM To evaluate safety,feasibility and effectiveness of NMES on functional capacity and muscle strength in patients before and after cardiac surgery.METHODS We performed a search on Pubmed,Physiotherapy Evidence Database(PEDro),Embase and CINAHL databases,selecting papers published between December 2012 and April 2023 and identified published randomized controlled trials(RCTs)that included implementation of NMES in patients before after cardiac surgery.RCTs were assessed for methodological rigor and risk of bias via the PEDro.The primary outcomes were safety and functional capacity and the secondary outcomes were muscle strength and function.RESULTS Ten studies were included in our systematic review,resulting in 703 participants.Almost half of them performed NMES and the other half were included in the control group,treated with usual care.Nine studies investigated patients after cardiac surgery and 1 study before cardiac surgery.Functional capacity was assessed in 8 studies via 6MWT or other indices,and improved only in 1 study before and in 1 after cardiac surgery.Nine studies explored the effects of NMES on muscle strength and function and,most of them,found increase of muscle strength and improvement in muscle function after NMES.NMES was safe in all studies without any significant complication.CONCLUSION NMES is safe,feasible and has beneficial effects on muscle strength and function in patients after cardiac surgery,but has no significant effect on functional capacity.展开更多
The debate about the safety of genetically modified (GM) food has attracted public attention in concurrence with the rapid development of agricultural biotechnology. This paper examines the consumers' perceptions o...The debate about the safety of genetically modified (GM) food has attracted public attention in concurrence with the rapid development of agricultural biotechnology. This paper examines the consumers' perceptions on the safety of GM food in China. Based on a unique survey dataset, this study shows that consumers in urban China have significantly changed their perceptions on GM food safety. The percentage of consumers who perceived such food as unsafe for consumption increased by more than 30% in the 2002-2012 period. Approximately half of the consumers did not have an opinion on this issue. Major shifts have been occurred after 2010, likely because of the increasing influence of negative media reports on GM technology in recent years. Several individual and household's characteristics are shown to significantly affect consumers' perceptions on GM food safety, such as gender, education, food allergy experience and resident city size. The paper concludes with policy implications.展开更多
This study provides an economics assessment of various food safety measures in China. A choice experiment approach is used to elicit Chinese consumer preferences for various food safety attributes using data from a 20...This study provides an economics assessment of various food safety measures in China. A choice experiment approach is used to elicit Chinese consumer preferences for various food safety attributes using data from a 2008 urban consumer survey. An alternative welfare calculation is used to model aggregate market impacts of select food safety measures. Our results show that the largest welfare gains are found in the current government-run certiifcation program. The implementation of a third-party certiifcation system, a traceability network and a product label would generate signiifcant value and would help reduce current system inefifciencies in China. This study builds on previous research and provides an alternative approach for calculating consumer valuation of safety and quality attributes that can be used to estimate aggregate economic and welfare impacts.展开更多
The overall objective of this research was to determine consumers' preferences for quality and safety attributes of milk products using advances in the best-worst scaling approach. A list of 16 quality and safety att...The overall objective of this research was to determine consumers' preferences for quality and safety attributes of milk products using advances in the best-worst scaling approach. A list of 16 quality and safety attributes of milk products based on previous studies was compiled and used in this study. The balanced incomplete block design technique was used to build the questionnaire administered to respondents in the data collection. The multinomial mixed logit was employed to analyze the data. Results suggest that nutritive value, shelf life, availability, purity and safety are the most important attributes of milk product; while origin, fat content, food miles, packaging and handling convenience are the least importance attributes of milk products to consumers The study concludes that demand for dairy products can be significantly stimulated in the study area when these most important attributes have been considered by producers, processors and marketers.展开更多
The objective of this study was to explain the determinants of the fresh vegetables purchase decision by Chinese urban consumers in Beijing including awareness and attitudes to food safety, and their willingness to p...The objective of this study was to explain the determinants of the fresh vegetables purchase decision by Chinese urban consumers in Beijing including awareness and attitudes to food safety, and their willingness to pay (WTP) more for specific safety characteristics when buying fresh vegetables. The research rationale arises out of a history of food safety scares and scandals in China, and a national government response to promote quality assurance and safety through labelling. The primary hypothesis was that an understanding of food safety systems and product labelling, and trust in supply chain integrity would be key determinants in consumer willingness to purchase and pay more for safety assured vegetables. Based on a questionnaire survey of consumers in Beijing, the analysis found that the major factors underlying the purchase decision of fresh vegetables were product freshness, convenience and competitive price rather than assured product labelling. The decisions whether to purchase assurance-labelled vegetables and WTP more for chemical residue-free product were analysed by binomial and ordinal multinomial logit modelling respectively. It revealed a WTP moreof between 20% and 40%. Monthly household income was a key determinant of both quality assured product and WTP, together with degree of concern over residues, trust in retailer and assurance labels and place of purchase. The results suggest much still remains to be done to build trust though rigorous monitoring and enforcement of food safety standards to improve supply chain integrity and consumer confidence.展开更多
Established within the framework of the World Trade Organization (WTO), the Trade Policy Review Mechanism (TPRM) reviews periodically the trade policies of all WTO Members. The review includes many aspects of food...Established within the framework of the World Trade Organization (WTO), the Trade Policy Review Mechanism (TPRM) reviews periodically the trade policies of all WTO Members. The review includes many aspects of food safety regulation. China's trade policy is reviewed every two years. This paper analyses in detail the reviews of China's trade policy in 2006, 2008, 2010, 2012 and 2014. It focuses in particular on food safety laws and types of standards, alignment of domestic standards with international standards, the role of different domestic institutions, transparency and notification of food safety measures under the WTO agreements on Sanitary and Phytosanitary Measures (SPS) and on Technical Barriers to Trade (TBTAgreement), import and export, and geographical indications (GIs). It concludes that the WTO TPRM can contribute, within its mandate, to reform of Chinese food safety laws and improvement of food safety in China. it notes that China has already undertaken substantial reforms of its system for regulating food safety. It recommends that China should continue to participate actively in the TPRM, follow its own path with regard to alignment and learn selectively from other WTO Members.展开更多
Efficient and reliable energy storage systems are crucial for our modern society.Lithium-ion batteries(LIBs)with excellent performance are widely used in portable electronics and electric vehicles(EVs),but frequent fi...Efficient and reliable energy storage systems are crucial for our modern society.Lithium-ion batteries(LIBs)with excellent performance are widely used in portable electronics and electric vehicles(EVs),but frequent fires and explosions limit their further and more widespread applications.This review summarizes aspects of LIB safety and discusses the related issues,strategies,and testing standards.Specifically,it begins with a brief introduction to LIB working principles and cell structures,and then provides an overview of the notorious thermal runaway,with an emphasis on the effects of mechanical,electrical,and thermal abuse.The following sections examine strategies for improving cell safety,including approaches through cell chemistry,cooling,and balancing,afterwards describing current safety standards and corresponding tests.The review concludes with insights into potential future developments and the prospects for safer LIBs.展开更多
This paper describes the shortcomings and difficulties of power company security construction, such as site management for construction site security monitoring personnel is limited, in recent years , rural power grid...This paper describes the shortcomings and difficulties of power company security construction, such as site management for construction site security monitoring personnel is limited, in recent years , rural power grids and Urban Network alteration Faced with new situation. The use of advanced science and technology and communication terminal in order to better strengthen the means of power construction site safety supervision, improve the level of safety production supervision, design and development of a new electrical safety job site intelligent monitoring devices. The device consists of three parts of the remote wide angle 360 degrees of portable video surveillance equipment and 3G smart terminal equipment and portable battery. Through the application of such a device, professionals can remotely monitor the construction job site safety, diagnose, and effectively improve the security of the electricity sector management and reduce security risks and personnel on-site monitoring costs for improving the security of the entire power industry field operations with significance.展开更多
A generalized mathematical model of human body current threshold for perception was established and the current flowing through human body could be arbitrary cyclical waveforms.The relationship between human body curr...A generalized mathematical model of human body current threshold for perception was established and the current flowing through human body could be arbitrary cyclical waveforms.The relationship between human body current threshold for perception and current frequency, true root mean square(RMS) value and influence factor was described.A test system was established based on electroencephalogram(EEG) to study the relationship between human body current threshold for perception and current waveform, frequency ...展开更多
This paper describes a concept for an independent and redundant safety concept for Lithium batteries in Electric and Hybrid Electric Vehicles. This concept includes an emergency cooling system based on pressurized car...This paper describes a concept for an independent and redundant safety concept for Lithium batteries in Electric and Hybrid Electric Vehicles. This concept includes an emergency cooling system based on pressurized carbon dioxide (CO2). Since carbon dioxide (CO2) is a possible medium of future mobile air conditioning (MAC) systems, the MAC system can be utilized for the one-time emergency cooling described in this paper. In the first part of the paper, some major safety aspects of automotive Li batteries are highlighted. In the second section, the paper describes a technical approach, how these batteries can be made safer. Pressurized CO2, which is a promising candidate for cooling liquids used in future mobile air conditioning (MAC) systems, is used to effectively cool down an overheating or up-heating battery in a critical state. The safety system thereby is not based on an electrical effect, but on a direct and fast-reacting thermal conduction, avoiding a thermal runaway of individual cells. The application of the proposed system is to act preventively just before the thermal runaway gets uncontrollable. In this case, the limited amount of CO2, which is available in the MAC system, fulfils the emergency cooling requirements. The combination of standard car components for the concept leads to an only moderate increase of the total weight and the additional system costs. Therefore, the described system might be of interest for car, battery and air conditioning system producers. This paper explains that the synergetic combination of CO2-based MAC systems and Li-based batteries is an innovative approach to improve environmental compatibility in future vehicles. The concept is proven experimentally on a lab scale with battery cells and battery packs consisting of four serially connected cells, respectively.展开更多
By determining the distribution and extent of geological structures surrounding the Mingyan Tunnel,Xicheng Town,Helong City,Jilin Province,we can evaluate the stability of the rock mass and assess potential hazards du...By determining the distribution and extent of geological structures surrounding the Mingyan Tunnel,Xicheng Town,Helong City,Jilin Province,we can evaluate the stability of the rock mass and assess potential hazards during tunnel construction.We use the high-density resistivity method to analyze the subsurface structure of the study area.Conductive anomalies are likely to represent joint and fissure systems within strongly weathered host rocks,and the bedrock surrounding the tunnel is relatively stable and does not contain well-developed faults.High-density resistivity analysis can provide valuable information in the context of tunnel engineering and safety.展开更多
Similar to conventional automobiles,same safety problems exist in electric vehicles.In the meantime,since its structural and power features are different,electric vehicles have their particular safety problems.Both do...Similar to conventional automobiles,same safety problems exist in electric vehicles.In the meantime,since its structural and power features are different,electric vehicles have their particular safety problems.Both domestic and international organizations have released some safety standards for electric vehicles which have also been added and complemented along with the development and research of electric vehicles.展开更多
In this paper it has been presented the ELF Survey Meter and its application for investigation of presence of electric and magnetic fields strength in uranium conversion facilities,especially to investigate the effect...In this paper it has been presented the ELF Survey Meter and its application for investigation of presence of electric and magnetic fields strength in uranium conversion facilities,especially to investigate the effect of electric and magnetic sources on the operation of electrical controllers like PLC instruments, electrical drivers and actuators which are sensitive to presence of electrical and magnetic fields and also the effect of high voltage power lines展开更多
As an efficient and advanced line inspection method, helicopter line patrol is gradually more and more used in transmission lines inspection, promoting the elaborate operation of transmission lines and reducing the ma...As an efficient and advanced line inspection method, helicopter line patrol is gradually more and more used in transmission lines inspection, promoting the elaborate operation of transmission lines and reducing the management cost. However, as a 'floating-potential conductor' near to a high-voltage transmission line, the helicopter would be at a high electric field region;and bring security risk to equipment and operating personnel. In this paper, the electric field strength near the cabin at locations of different distance from transmission lines is investigated by calculation, and the field in the helicopter cabin is also calculated with finite element method (FEM). The result indicates that the potential difference becomes higher with the decrease of the distance between the helicopter and transmission line. Considering the discharge energy and the guarantee of the persons’ safety, the safety distance is determined as d≥15 m.展开更多
Based on the analysis of weakness on the safety of traditional electric detonators, a BJ-l safety electric detonator initiatingsystem and its corresponding safe examination technique were successfully developed. By le...Based on the analysis of weakness on the safety of traditional electric detonators, a BJ-l safety electric detonator initiatingsystem and its corresponding safe examination technique were successfully developed. By leading false foot wires and taking advantageof the transmitting frequency band of Mo-Zn ferrite, detonators in this new system can completely impede the direct induction of outsidecrosstalk that may cause casual firing in the ordinary as well as eleclromagnetic ones. Possible causality by lightning was discussed. Results are presented, of its safety tests on resistance to direct and alternating current, electrostatic, and crosstalk induced by damp leakagein saturated salty water.展开更多
The battery management system(BMS)is the main safeguard of a battery system for electric propulsion and machine electrifcation.It is tasked to ensure reliable and safe operation of battery cells connected to provide h...The battery management system(BMS)is the main safeguard of a battery system for electric propulsion and machine electrifcation.It is tasked to ensure reliable and safe operation of battery cells connected to provide high currents at high voltage levels.In addition to efectively monitoring all the electrical parameters of a battery pack system,such as the voltage,current,and temperature,the BMS is also used to improve the battery performance with proper safety measures within the system.With growing acceptance of lithium-ion batteries,major industry sectors such as the automotive,renewable energy,manufacturing,construction,and even some in the mining industry have brought forward the mass transition from fossil fuel dependency to electric powered machinery and redefned the world of energy storage.Hence,the functional safety considerations,which are those relating to automatic protection,in battery management for battery pack technologies are particularly important to ensure that the overall electrical system,regardless of whether it is for electric transportation or stationary energy storage,is in accordance with high standards of safety,reliability,and quality.If the system or product fails to meet functional and other safety requirements on account of faulty design or a sequence of failure events,then the environment,people,and property could be endangered.This paper analyzed the details of BMS for electric transportation and large-scale energy storage systems,particularly in areas concerned with hazardous environment.The analysis covers the aspect of functional safety that applies to BMS and is in accordance with the relevant industrial standards.A comprehensive evaluation of the components,architecture,risk reduction techniques,and failure mode analysis applicable to BMS operation was also presented.The article further provided recommendations on safety design and performance optimization in relation to the overall BMS integration.展开更多
This article anlayzes the different requirements for electrical toys safety between GB 6675-2003 and GB19865-2005. This information is summed up in table form to make it easy for toy designers and manufacturers to gra...This article anlayzes the different requirements for electrical toys safety between GB 6675-2003 and GB19865-2005. This information is summed up in table form to make it easy for toy designers and manufacturers to grasp the new standard.展开更多
In the development process of the society nowadays,electrical engineering has been widely used with remarkable results,but there are still some problems in the course of actual management,which requires effective tech...In the development process of the society nowadays,electrical engineering has been widely used with remarkable results,but there are still some problems in the course of actual management,which requires effective technical measures to control the quality in electrical engineering and the enhancement of safety management work.Therefore,in order to better ensure safety management requirements in electrical engineering and strengthen related trainings and thus better carried out safety management and quality control to meet respective requirements in the real world,in this paper,a brief analysis is conducted in quality control and safety management in electrical engineering.展开更多
This paper covers the safely requirements and inspection methods for insulating components used in electrical accessories by an analyzing the properties of the insulating components used in electrical accessories base...This paper covers the safely requirements and inspection methods for insulating components used in electrical accessories by an analyzing the properties of the insulating components used in electrical accessories based on the standard of IEC 60884.展开更多
文摘Various industries today rely on the support of electromechanical equipment,expanding its scope of application and leading to an increase in electromechanical installation projects.However,due to the high level of expertise required and the potential risks involved,it is crucial to emphasize safety management during construction.This paper delves into the significance of construction safety management for electromechanical installation projects,identifies common problems encountered during construction,and proposes solutions.This analysis aims to provide relevant personnel with essential guidance and references for managing electromechanical installation projects safely.
文摘BACKGROUND Lack of mobilization and prolonged stay in the intensive care unit(ICU)are major factors resulting in the development of ICU-acquired muscle weakness(ICUAW).ICUAW is a type of skeletal muscle dysfunction and a common complication of patients after cardiac surgery,and may be a risk factor for prolonged duration of mechanical ventilation,associated with a higher risk of readmission and higher mortality.Early mobilization in the ICU after cardiac surgery has been found to be low with a significant trend to increase over ICU stay and is also associated with a reduced duration of mechanical ventilation and ICU length of stay.Neuromuscular electrical stimulation(NMES)is an alternative modality of exercise in patients with muscle weakness.A major advantage of NMES is that it can be applied even in sedated patients in the ICU,a fact that might enhance early mobilization in these patients.AIM To evaluate safety,feasibility and effectiveness of NMES on functional capacity and muscle strength in patients before and after cardiac surgery.METHODS We performed a search on Pubmed,Physiotherapy Evidence Database(PEDro),Embase and CINAHL databases,selecting papers published between December 2012 and April 2023 and identified published randomized controlled trials(RCTs)that included implementation of NMES in patients before after cardiac surgery.RCTs were assessed for methodological rigor and risk of bias via the PEDro.The primary outcomes were safety and functional capacity and the secondary outcomes were muscle strength and function.RESULTS Ten studies were included in our systematic review,resulting in 703 participants.Almost half of them performed NMES and the other half were included in the control group,treated with usual care.Nine studies investigated patients after cardiac surgery and 1 study before cardiac surgery.Functional capacity was assessed in 8 studies via 6MWT or other indices,and improved only in 1 study before and in 1 after cardiac surgery.Nine studies explored the effects of NMES on muscle strength and function and,most of them,found increase of muscle strength and improvement in muscle function after NMES.NMES was safe in all studies without any significant complication.CONCLUSION NMES is safe,feasible and has beneficial effects on muscle strength and function in patients after cardiac surgery,but has no significant effect on functional capacity.
基金supported by the National Natural Science Foundation of China (71333013)the National Key Program on Genetically Modified New Varieties of China (2011ZX08015-002A)the Templeton Foundation (through Rutgers University, USA)
文摘The debate about the safety of genetically modified (GM) food has attracted public attention in concurrence with the rapid development of agricultural biotechnology. This paper examines the consumers' perceptions on the safety of GM food in China. Based on a unique survey dataset, this study shows that consumers in urban China have significantly changed their perceptions on GM food safety. The percentage of consumers who perceived such food as unsafe for consumption increased by more than 30% in the 2002-2012 period. Approximately half of the consumers did not have an opinion on this issue. Major shifts have been occurred after 2010, likely because of the increasing influence of negative media reports on GM technology in recent years. Several individual and household's characteristics are shown to significantly affect consumers' perceptions on GM food safety, such as gender, education, food allergy experience and resident city size. The paper concludes with policy implications.
基金supported by the US National Science Foundation (0912174)
文摘This study provides an economics assessment of various food safety measures in China. A choice experiment approach is used to elicit Chinese consumer preferences for various food safety attributes using data from a 2008 urban consumer survey. An alternative welfare calculation is used to model aggregate market impacts of select food safety measures. Our results show that the largest welfare gains are found in the current government-run certiifcation program. The implementation of a third-party certiifcation system, a traceability network and a product label would generate signiifcant value and would help reduce current system inefifciencies in China. This study builds on previous research and provides an alternative approach for calculating consumer valuation of safety and quality attributes that can be used to estimate aggregate economic and welfare impacts.
文摘The overall objective of this research was to determine consumers' preferences for quality and safety attributes of milk products using advances in the best-worst scaling approach. A list of 16 quality and safety attributes of milk products based on previous studies was compiled and used in this study. The balanced incomplete block design technique was used to build the questionnaire administered to respondents in the data collection. The multinomial mixed logit was employed to analyze the data. Results suggest that nutritive value, shelf life, availability, purity and safety are the most important attributes of milk product; while origin, fat content, food miles, packaging and handling convenience are the least importance attributes of milk products to consumers The study concludes that demand for dairy products can be significantly stimulated in the study area when these most important attributes have been considered by producers, processors and marketers.
文摘The objective of this study was to explain the determinants of the fresh vegetables purchase decision by Chinese urban consumers in Beijing including awareness and attitudes to food safety, and their willingness to pay (WTP) more for specific safety characteristics when buying fresh vegetables. The research rationale arises out of a history of food safety scares and scandals in China, and a national government response to promote quality assurance and safety through labelling. The primary hypothesis was that an understanding of food safety systems and product labelling, and trust in supply chain integrity would be key determinants in consumer willingness to purchase and pay more for safety assured vegetables. Based on a questionnaire survey of consumers in Beijing, the analysis found that the major factors underlying the purchase decision of fresh vegetables were product freshness, convenience and competitive price rather than assured product labelling. The decisions whether to purchase assurance-labelled vegetables and WTP more for chemical residue-free product were analysed by binomial and ordinal multinomial logit modelling respectively. It revealed a WTP moreof between 20% and 40%. Monthly household income was a key determinant of both quality assured product and WTP, together with degree of concern over residues, trust in retailer and assurance labels and place of purchase. The results suggest much still remains to be done to build trust though rigorous monitoring and enforcement of food safety standards to improve supply chain integrity and consumer confidence.
基金Peking University Shenzhen Graduate School, ChinaPeking University School of Transnational Law, China
文摘Established within the framework of the World Trade Organization (WTO), the Trade Policy Review Mechanism (TPRM) reviews periodically the trade policies of all WTO Members. The review includes many aspects of food safety regulation. China's trade policy is reviewed every two years. This paper analyses in detail the reviews of China's trade policy in 2006, 2008, 2010, 2012 and 2014. It focuses in particular on food safety laws and types of standards, alignment of domestic standards with international standards, the role of different domestic institutions, transparency and notification of food safety measures under the WTO agreements on Sanitary and Phytosanitary Measures (SPS) and on Technical Barriers to Trade (TBTAgreement), import and export, and geographical indications (GIs). It concludes that the WTO TPRM can contribute, within its mandate, to reform of Chinese food safety laws and improvement of food safety in China. it notes that China has already undertaken substantial reforms of its system for regulating food safety. It recommends that China should continue to participate actively in the TPRM, follow its own path with regard to alignment and learn selectively from other WTO Members.
基金financially supported by the National Key Basic Research Program of China(No.2014CB932400)the Joint Fund of the National Natural Science Foundation of China(No.U1401243)+3 种基金the National Natural Science Foundation of China(No.51232005)the Shenzhen Technical Plan Project(No.JCYJ20150529164918735,CYJ20170412170911187,KQJSCX20160226191136)the Guangdong Technical Plan Project(No.2015TX01N011)the financial support by Bio4Energy program。
文摘Efficient and reliable energy storage systems are crucial for our modern society.Lithium-ion batteries(LIBs)with excellent performance are widely used in portable electronics and electric vehicles(EVs),but frequent fires and explosions limit their further and more widespread applications.This review summarizes aspects of LIB safety and discusses the related issues,strategies,and testing standards.Specifically,it begins with a brief introduction to LIB working principles and cell structures,and then provides an overview of the notorious thermal runaway,with an emphasis on the effects of mechanical,electrical,and thermal abuse.The following sections examine strategies for improving cell safety,including approaches through cell chemistry,cooling,and balancing,afterwards describing current safety standards and corresponding tests.The review concludes with insights into potential future developments and the prospects for safer LIBs.
文摘This paper describes the shortcomings and difficulties of power company security construction, such as site management for construction site security monitoring personnel is limited, in recent years , rural power grids and Urban Network alteration Faced with new situation. The use of advanced science and technology and communication terminal in order to better strengthen the means of power construction site safety supervision, improve the level of safety production supervision, design and development of a new electrical safety job site intelligent monitoring devices. The device consists of three parts of the remote wide angle 360 degrees of portable video surveillance equipment and 3G smart terminal equipment and portable battery. Through the application of such a device, professionals can remotely monitor the construction job site safety, diagnose, and effectively improve the security of the electricity sector management and reduce security risks and personnel on-site monitoring costs for improving the security of the entire power industry field operations with significance.
基金Supported by the Ministry of Science and Technology of China (No. NCSTE-2006-JKZX-167)Beijing Key Laboratory (Measurement and Control of Electro-mechanical Systems) (No. 82063005)
文摘A generalized mathematical model of human body current threshold for perception was established and the current flowing through human body could be arbitrary cyclical waveforms.The relationship between human body current threshold for perception and current frequency, true root mean square(RMS) value and influence factor was described.A test system was established based on electroencephalogram(EEG) to study the relationship between human body current threshold for perception and current waveform, frequency ...
文摘This paper describes a concept for an independent and redundant safety concept for Lithium batteries in Electric and Hybrid Electric Vehicles. This concept includes an emergency cooling system based on pressurized carbon dioxide (CO2). Since carbon dioxide (CO2) is a possible medium of future mobile air conditioning (MAC) systems, the MAC system can be utilized for the one-time emergency cooling described in this paper. In the first part of the paper, some major safety aspects of automotive Li batteries are highlighted. In the second section, the paper describes a technical approach, how these batteries can be made safer. Pressurized CO2, which is a promising candidate for cooling liquids used in future mobile air conditioning (MAC) systems, is used to effectively cool down an overheating or up-heating battery in a critical state. The safety system thereby is not based on an electrical effect, but on a direct and fast-reacting thermal conduction, avoiding a thermal runaway of individual cells. The application of the proposed system is to act preventively just before the thermal runaway gets uncontrollable. In this case, the limited amount of CO2, which is available in the MAC system, fulfils the emergency cooling requirements. The combination of standard car components for the concept leads to an only moderate increase of the total weight and the additional system costs. Therefore, the described system might be of interest for car, battery and air conditioning system producers. This paper explains that the synergetic combination of CO2-based MAC systems and Li-based batteries is an innovative approach to improve environmental compatibility in future vehicles. The concept is proven experimentally on a lab scale with battery cells and battery packs consisting of four serially connected cells, respectively.
基金Supported by The National Natural Science Foundation of China(41504076)Jilin Science and Technological Development Program(20180101093JC)。
文摘By determining the distribution and extent of geological structures surrounding the Mingyan Tunnel,Xicheng Town,Helong City,Jilin Province,we can evaluate the stability of the rock mass and assess potential hazards during tunnel construction.We use the high-density resistivity method to analyze the subsurface structure of the study area.Conductive anomalies are likely to represent joint and fissure systems within strongly weathered host rocks,and the bedrock surrounding the tunnel is relatively stable and does not contain well-developed faults.High-density resistivity analysis can provide valuable information in the context of tunnel engineering and safety.
文摘Similar to conventional automobiles,same safety problems exist in electric vehicles.In the meantime,since its structural and power features are different,electric vehicles have their particular safety problems.Both domestic and international organizations have released some safety standards for electric vehicles which have also been added and complemented along with the development and research of electric vehicles.
文摘In this paper it has been presented the ELF Survey Meter and its application for investigation of presence of electric and magnetic fields strength in uranium conversion facilities,especially to investigate the effect of electric and magnetic sources on the operation of electrical controllers like PLC instruments, electrical drivers and actuators which are sensitive to presence of electrical and magnetic fields and also the effect of high voltage power lines
文摘As an efficient and advanced line inspection method, helicopter line patrol is gradually more and more used in transmission lines inspection, promoting the elaborate operation of transmission lines and reducing the management cost. However, as a 'floating-potential conductor' near to a high-voltage transmission line, the helicopter would be at a high electric field region;and bring security risk to equipment and operating personnel. In this paper, the electric field strength near the cabin at locations of different distance from transmission lines is investigated by calculation, and the field in the helicopter cabin is also calculated with finite element method (FEM). The result indicates that the potential difference becomes higher with the decrease of the distance between the helicopter and transmission line. Considering the discharge energy and the guarantee of the persons’ safety, the safety distance is determined as d≥15 m.
文摘Based on the analysis of weakness on the safety of traditional electric detonators, a BJ-l safety electric detonator initiatingsystem and its corresponding safe examination technique were successfully developed. By leading false foot wires and taking advantageof the transmitting frequency band of Mo-Zn ferrite, detonators in this new system can completely impede the direct induction of outsidecrosstalk that may cause casual firing in the ordinary as well as eleclromagnetic ones. Possible causality by lightning was discussed. Results are presented, of its safety tests on resistance to direct and alternating current, electrostatic, and crosstalk induced by damp leakagein saturated salty water.
基金supported by Azure Mining Technology,CCTEG,and the University of Wollongong.
文摘The battery management system(BMS)is the main safeguard of a battery system for electric propulsion and machine electrifcation.It is tasked to ensure reliable and safe operation of battery cells connected to provide high currents at high voltage levels.In addition to efectively monitoring all the electrical parameters of a battery pack system,such as the voltage,current,and temperature,the BMS is also used to improve the battery performance with proper safety measures within the system.With growing acceptance of lithium-ion batteries,major industry sectors such as the automotive,renewable energy,manufacturing,construction,and even some in the mining industry have brought forward the mass transition from fossil fuel dependency to electric powered machinery and redefned the world of energy storage.Hence,the functional safety considerations,which are those relating to automatic protection,in battery management for battery pack technologies are particularly important to ensure that the overall electrical system,regardless of whether it is for electric transportation or stationary energy storage,is in accordance with high standards of safety,reliability,and quality.If the system or product fails to meet functional and other safety requirements on account of faulty design or a sequence of failure events,then the environment,people,and property could be endangered.This paper analyzed the details of BMS for electric transportation and large-scale energy storage systems,particularly in areas concerned with hazardous environment.The analysis covers the aspect of functional safety that applies to BMS and is in accordance with the relevant industrial standards.A comprehensive evaluation of the components,architecture,risk reduction techniques,and failure mode analysis applicable to BMS operation was also presented.The article further provided recommendations on safety design and performance optimization in relation to the overall BMS integration.
文摘This article anlayzes the different requirements for electrical toys safety between GB 6675-2003 and GB19865-2005. This information is summed up in table form to make it easy for toy designers and manufacturers to grasp the new standard.
文摘In the development process of the society nowadays,electrical engineering has been widely used with remarkable results,but there are still some problems in the course of actual management,which requires effective technical measures to control the quality in electrical engineering and the enhancement of safety management work.Therefore,in order to better ensure safety management requirements in electrical engineering and strengthen related trainings and thus better carried out safety management and quality control to meet respective requirements in the real world,in this paper,a brief analysis is conducted in quality control and safety management in electrical engineering.
文摘This paper covers the safely requirements and inspection methods for insulating components used in electrical accessories by an analyzing the properties of the insulating components used in electrical accessories based on the standard of IEC 60884.