As the rapid development of more powerful and safer lithiumion batteries, the mechanism study of gases evolution is attacking more and more attention in recent years. Especially under overcharge/discharge and/or high-...As the rapid development of more powerful and safer lithiumion batteries, the mechanism study of gases evolution is attacking more and more attention in recent years. Especially under overcharge/discharge and/or high-temperature working condition.展开更多
Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and vali...Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.展开更多
The study of arc behavior is important to understand the dynamic phenomena concerning the interruption process in a variety of switching devices. This paper is devoted to investigate the influence of gassing material ...The study of arc behavior is important to understand the dynamic phenomena concerning the interruption process in a variety of switching devices. This paper is devoted to investigate the influence of gassing material on blow open force and arc motion. To one double- breaker model, measuring the arc current, voltage and force acting on the moving conductor, the characteristics of the ratio of the emerging blow open force over arc power FB/（ui） could be obtained. With the help of a 2-D optical fiber measurement system, to one arc chamber model, arc motion behavior was measured, too. It is demonstrated that, with the action of gassing material, FB/（ui） will increase 2.5 times, and the arc will enter the splitter plates much easier.展开更多
Taking into account the properties of the arc plasma and the electromagnetic, heat and radiative phenomena, commercial computational fluid dynamics software PHOENICS has been adapted and modified to develop the three-...Taking into account the properties of the arc plasma and the electromagnetic, heat and radiative phenomena, commercial computational fluid dynamics software PHOENICS has been adapted and modified to develop the three-dimensional magneto-hydrodynamic （MHD） model of arc in a low voltage circuit breaker. The effects of the arc ignition location, venting size and gassing material on arc behavior have been investigated. The analysis of the results show that the arc velocity accelerates with the increase in the distance between arc ignition location and of the venting size, and the existence of the gassing material is beneficial to improving the arc voltage and reducing the arc temperature.展开更多
Computational fluid dynamics(CFD)and experimental analyses of some of the basic characteristics of air sparging in a tall stirred vessel equipped with a three-stage impeller are presented.The impeller was assembled fr...Computational fluid dynamics(CFD)and experimental analyses of some of the basic characteristics of air sparging in a tall stirred vessel equipped with a three-stage impeller are presented.The impeller was assembled from a radial ABT impeller as the lower,a turbine 6 PBT45 as the middle and an axial Scaba-type 3SHP1 impeller as the upper.All the impellers were of the same diameter,i.e.,225 mm,while the vessel diameter was 450 mm.The impeller’s rotational speed was 178 r·min-1.The aeration regime was established with an air volumetric flow rate of 28.3 m3·h-1.To the best of our knowledge,this study is the first to consider the very high gassing rate by means of CFD in a tank stirred by three-stage axial/radial impellers.The numerical simulation was performed using the ANSYS Fluent(R17.2,2016)code for solving the governing equations of fluid dynamics in single-and multi-phase systems.While discussing the bubble size distribution,a discrete population balance model(PBM)was used.Adopting CFD,the stirring power and the total void fraction(the total gas holdup)were calculated.The results were in good agreement with the measured values using a laboratory experimental device.展开更多
In Chiapas highlands to southeast of Mexico, the scarcity of water is worrying, according to technical reports of the IPCC the runoff will less between 150 to 250 mm per year in the southeast of Mexico, this situation...In Chiapas highlands to southeast of Mexico, the scarcity of water is worrying, according to technical reports of the IPCC the runoff will less between 150 to 250 mm per year in the southeast of Mexico, this situation will increase the problems of water availability in Chiapas highlands in the future. For actually more of 18,160 small rural indigenous communities (SRIC) in Chiapas there is not drinking water. In order to contribute a given solution to scarcity of drinking water in the SRIC, The Autonomous University of Chiapas (UNACH in its Spanish acronym) and Mexican Institute of Water Technology (IMTA in its Spanish acronym) designed and constructed in 1999 the Rain Water Harvesting (RWH) in Yalentay municipality of Zinacantan in Chiapas, Mexico. The scientific and technical contributions of RWH are: The design guarantee the water quality for a prolonged time of storage avoiding the photosynthesis inside the system;Not emitted greenhouse gasses because it doesn’t need any kind of fossil fuels;Not produces anything kind of damage to the environment;It has to be inexpensive, using in its construction manpower and materials from de region;Store the maximum quantity of water in the minimum space. The RWH has increased the standard of living of the habitants from Yalentay and improving their health conditions.展开更多
中国电子学会已成功申办第31届国际无线电科学(联盟)大会The 31th URSI General Assembly&Scientific Symposium(URSI GASS’2014),将于2014年8月16日~23日在北京召开。原计划于2014年召开第11届国际天线、电波传播和电磁理论学术...中国电子学会已成功申办第31届国际无线电科学(联盟)大会The 31th URSI General Assembly&Scientific Symposium(URSI GASS’2014),将于2014年8月16日~23日在北京召开。原计划于2014年召开第11届国际天线、电波传播和电磁理论学术研讨会The 11Th International Symposium On Antenna,Propagation and EM Theory(ISAPE’2014),该会议所涉及的学术交流方向和领域完全被URSI GASS’2014覆盖,经中国电子学会电波传播分会研究并报请中国电子学会批准,不再单独举办ISAPE’2014,其会议内容全部并入URSI GASS’2014。URSI GASS’2014是中国电子学会2014年的重点学术活动,是在我国举办的全世界无线电领域的"奥林匹克大会"。展开更多
基金partially supported by the National Natural Science Foundation of China (grant no. 22021001, 22179111)the Ministry of Science and Technology of China (grant no. 2021YFA1201900)+3 种基金the Basic Research Program of Tan Kah Kee Innovation Laboratory (grant no. RD2021070401)the Principal Fund from Xiamen University (grant no. 20720210015)the Fundamental Research Funds for the Central Universities (grant no. 20720220010)the National Natural Science Foundation of China (grant no. 22202082)。
文摘As the rapid development of more powerful and safer lithiumion batteries, the mechanism study of gases evolution is attacking more and more attention in recent years. Especially under overcharge/discharge and/or high-temperature working condition.
基金supported by the National Key Basic Research Program of China(973 Program)2015CB251002National Natural Science Foundation of China under Grant 51521065,51577145+1 种基金the Fundamental Research Funds for the Central UniversitiesShaanxi Province Natural Science Foundation 2013JM-7010
文摘Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.
基金National Natural Science Foundation of China (NSFC) (No.50507016)
文摘The study of arc behavior is important to understand the dynamic phenomena concerning the interruption process in a variety of switching devices. This paper is devoted to investigate the influence of gassing material on blow open force and arc motion. To one double- breaker model, measuring the arc current, voltage and force acting on the moving conductor, the characteristics of the ratio of the emerging blow open force over arc power FB/（ui） could be obtained. With the help of a 2-D optical fiber measurement system, to one arc chamber model, arc motion behavior was measured, too. It is demonstrated that, with the action of gassing material, FB/（ui） will increase 2.5 times, and the arc will enter the splitter plates much easier.
基金The project supported by National Natural Science Foundation of China (No. 50507016) and the Specialized Research Fund forthe Doctoral Program of Higher Education (No. 20020698008) and the Doctorate Foundation of Xi'an Jiaotong University
文摘Taking into account the properties of the arc plasma and the electromagnetic, heat and radiative phenomena, commercial computational fluid dynamics software PHOENICS has been adapted and modified to develop the three-dimensional magneto-hydrodynamic （MHD） model of arc in a low voltage circuit breaker. The effects of the arc ignition location, venting size and gassing material on arc behavior have been investigated. The analysis of the results show that the arc velocity accelerates with the increase in the distance between arc ignition location and of the venting size, and the existence of the gassing material is beneficial to improving the arc voltage and reducing the arc temperature.
基金supported by the Slovenian Ministry of Education,Science and Sport under contract no.P2-0162.
文摘Computational fluid dynamics(CFD)and experimental analyses of some of the basic characteristics of air sparging in a tall stirred vessel equipped with a three-stage impeller are presented.The impeller was assembled from a radial ABT impeller as the lower,a turbine 6 PBT45 as the middle and an axial Scaba-type 3SHP1 impeller as the upper.All the impellers were of the same diameter,i.e.,225 mm,while the vessel diameter was 450 mm.The impeller’s rotational speed was 178 r·min-1.The aeration regime was established with an air volumetric flow rate of 28.3 m3·h-1.To the best of our knowledge,this study is the first to consider the very high gassing rate by means of CFD in a tank stirred by three-stage axial/radial impellers.The numerical simulation was performed using the ANSYS Fluent(R17.2,2016)code for solving the governing equations of fluid dynamics in single-and multi-phase systems.While discussing the bubble size distribution,a discrete population balance model(PBM)was used.Adopting CFD,the stirring power and the total void fraction(the total gas holdup)were calculated.The results were in good agreement with the measured values using a laboratory experimental device.
文摘In Chiapas highlands to southeast of Mexico, the scarcity of water is worrying, according to technical reports of the IPCC the runoff will less between 150 to 250 mm per year in the southeast of Mexico, this situation will increase the problems of water availability in Chiapas highlands in the future. For actually more of 18,160 small rural indigenous communities (SRIC) in Chiapas there is not drinking water. In order to contribute a given solution to scarcity of drinking water in the SRIC, The Autonomous University of Chiapas (UNACH in its Spanish acronym) and Mexican Institute of Water Technology (IMTA in its Spanish acronym) designed and constructed in 1999 the Rain Water Harvesting (RWH) in Yalentay municipality of Zinacantan in Chiapas, Mexico. The scientific and technical contributions of RWH are: The design guarantee the water quality for a prolonged time of storage avoiding the photosynthesis inside the system;Not emitted greenhouse gasses because it doesn’t need any kind of fossil fuels;Not produces anything kind of damage to the environment;It has to be inexpensive, using in its construction manpower and materials from de region;Store the maximum quantity of water in the minimum space. The RWH has increased the standard of living of the habitants from Yalentay and improving their health conditions.
文摘中国电子学会已成功申办第31届国际无线电科学(联盟)大会The 31th URSI General Assembly&Scientific Symposium(URSI GASS’2014),将于2014年8月16日~23日在北京召开。原计划于2014年召开第11届国际天线、电波传播和电磁理论学术研讨会The 11Th International Symposium On Antenna,Propagation and EM Theory(ISAPE’2014),该会议所涉及的学术交流方向和领域完全被URSI GASS’2014覆盖,经中国电子学会电波传播分会研究并报请中国电子学会批准,不再单独举办ISAPE’2014,其会议内容全部并入URSI GASS’2014。URSI GASS’2014是中国电子学会2014年的重点学术活动,是在我国举办的全世界无线电领域的"奥林匹克大会"。
