In order to explore the safe operation of UAVs in non-segregated airspace,a collision risk model for cylindrical UAVs based on conflict areas was constructed and the risk of conflict between manned and unmanned aerial...In order to explore the safe operation of UAVs in non-segregated airspace,a collision risk model for cylindrical UAVs based on conflict areas was constructed and the risk of conflict between manned and unmanned aerial vehicles was researched.According to the results of risk analysis,a strategy for solving the conflict of aircraft is proposed,and the risk assessment experiment of unmanned aerial vehicle(UAV)in non-isolated airspace conflict is carried out.The results show that under the experimental conditions,large unmanned aerial vehicles equipped with ADS-B,TCAS and other airborne sensing systems will indeed interfere with other aircraft in airspace when they enter non-isolated airspace.Especially when the number of aircraft in airspace is large,the automatic avoidance system of UAV will increase the avoidance time and trigger the safety alarm,but the safety level is still acceptable.This indicates that it is relatively safe for UAVs to enter non-isolated airspace under limited conditions.The results can be used as a reference for the safe operation of unmanned aerial vehicle(UAV)in non-isolated airspace.展开更多
The work illustrates the impossibility of decreasing entropy in a strictly random thermodynamic process in a non-isolated system using the example of heating a planet by solar radiation flux without and taking into ac...The work illustrates the impossibility of decreasing entropy in a strictly random thermodynamic process in a non-isolated system using the example of heating a planet by solar radiation flux without and taking into account its rotation around its own axis. That is, the second law of thermodynamics formulated for isolated systems continues to govern such systems. We have shown that in order to achieve a stationary state at lower values of temperature and entropy far from thermodynamic equilibrium at a maximum of temperature and entropy, it is necessary to have regular factors of nonrandom nature, one of which in this example is the rotation of the planet around its own axis. This means that the reason for the appearance of ordered structured objects in non-isolated thermodynamic systems is not the random process itself, but the action of dynamic control mechanisms, such as periodic external influences, nonlinear elements with positive feedback, catalysts for chemical reactions, etc. We present the plots with dependences of temperature and entropy versus time in non-isolated systems with purely random processes and in the presence of a control factor of non-random nature-rotation.展开更多
分析了SF6气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)局部放电产生的原因,结合现场应用实例,对2种GIS局部放电在线检测技术——超声波检测技术和特高频检测技术进行了应用比较,结果表明...分析了SF6气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)局部放电产生的原因,结合现场应用实例,对2种GIS局部放电在线检测技术——超声波检测技术和特高频检测技术进行了应用比较,结果表明特高频检测法灵敏度高、抗电磁干扰能力强、有效测量范围大,能准确检测GIS内部绝缘缺陷,适用于长期在线监测;超声波检测法定位准确,可作为特高频检测法的补充和辅助手段;2种方法综合利用可有效发现绝缘缺陷并实现准确定位。展开更多
对于电力气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)绝缘子沿面放电这类较为常见且严重的局部放电缺陷,目前还没有合适的诊断方法,为此采用振动法进行故障监测和诊断。对采集的GIS振动信...对于电力气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)绝缘子沿面放电这类较为常见且严重的局部放电缺陷,目前还没有合适的诊断方法,为此采用振动法进行故障监测和诊断。对采集的GIS振动信号进行小波包分析,发现GIS局部放电的能量主要集中在1.6~6.4kHz频段内;提出用1.6~6.4kHz频段作为特征频段,给出了局部放电特征系数,其定义为1.6~6.4kHz频段的总能量与6.4~12.8kHz频段的总能量的比值;通过观察特征系数的大小,与正常状态下的值进行比较,就可以判断GIS是否发生沿面放电缺陷;并且给出特征系数的阈值范围,对沿面放电严重程度进行划分。研究表明,该方法可以有效诊断GIS沿面放电故障,与其他方法相比,效果比较好。展开更多
In this paper, a criterion on the C^0-sufficiency for a function germ with non-isolated singularity is obtained analogously to that of Kuiper-Kuo for the case of isolated singularities. Moreover, the Kuiper Kuo condit...In this paper, a criterion on the C^0-sufficiency for a function germ with non-isolated singularity is obtained analogously to that of Kuiper-Kuo for the case of isolated singularities. Moreover, the Kuiper Kuo condition and the Thom condition for an analytic function germ with non-isolated singularity are proved to be equivalent.展开更多
高电压等级的气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)在发生大电流短路故障时,常常由于短路能量较大,故障设备烧蚀严重而无法确定故障位置和直接原因。针对此,采用扫描电子能谱(energy...高电压等级的气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)在发生大电流短路故障时,常常由于短路能量较大,故障设备烧蚀严重而无法确定故障位置和直接原因。针对此,采用扫描电子能谱(energy disperse spectroscopy,EDS)法对发生故障的220 k V某变电站GIS设备SF6气体分解产物及故障区域表面附着物进行分析研究,结合返厂解体,同时考虑断路器设备原件的成分组成,分析了造成事故的原因。同时,在实体220 k V GIS内试验研究了铁质金属颗粒对GIS绝缘强度的影响和绝缘劣化的危险程度。结果表明:GIS断路器内存在铁质金属异物是造成事故的直接原因,厂内安装控制不严造成的带缺陷出厂为间接原因;在同一电压等级下,金属异物越大对GIS的绝缘强度影响越明显,绝缘劣化越突出,GIS越易发生闪络事故。展开更多
基金The authors would like to thank National Nature Science Foundation of China under Grant(71701202)The special funding project of Civil Aviation University of China for the basic scientific research services of the Central University(3122013Z006).
文摘In order to explore the safe operation of UAVs in non-segregated airspace,a collision risk model for cylindrical UAVs based on conflict areas was constructed and the risk of conflict between manned and unmanned aerial vehicles was researched.According to the results of risk analysis,a strategy for solving the conflict of aircraft is proposed,and the risk assessment experiment of unmanned aerial vehicle(UAV)in non-isolated airspace conflict is carried out.The results show that under the experimental conditions,large unmanned aerial vehicles equipped with ADS-B,TCAS and other airborne sensing systems will indeed interfere with other aircraft in airspace when they enter non-isolated airspace.Especially when the number of aircraft in airspace is large,the automatic avoidance system of UAV will increase the avoidance time and trigger the safety alarm,but the safety level is still acceptable.This indicates that it is relatively safe for UAVs to enter non-isolated airspace under limited conditions.The results can be used as a reference for the safe operation of unmanned aerial vehicle(UAV)in non-isolated airspace.
文摘The work illustrates the impossibility of decreasing entropy in a strictly random thermodynamic process in a non-isolated system using the example of heating a planet by solar radiation flux without and taking into account its rotation around its own axis. That is, the second law of thermodynamics formulated for isolated systems continues to govern such systems. We have shown that in order to achieve a stationary state at lower values of temperature and entropy far from thermodynamic equilibrium at a maximum of temperature and entropy, it is necessary to have regular factors of nonrandom nature, one of which in this example is the rotation of the planet around its own axis. This means that the reason for the appearance of ordered structured objects in non-isolated thermodynamic systems is not the random process itself, but the action of dynamic control mechanisms, such as periodic external influences, nonlinear elements with positive feedback, catalysts for chemical reactions, etc. We present the plots with dependences of temperature and entropy versus time in non-isolated systems with purely random processes and in the presence of a control factor of non-random nature-rotation.
文摘分析了SF6气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)局部放电产生的原因,结合现场应用实例,对2种GIS局部放电在线检测技术——超声波检测技术和特高频检测技术进行了应用比较,结果表明特高频检测法灵敏度高、抗电磁干扰能力强、有效测量范围大,能准确检测GIS内部绝缘缺陷,适用于长期在线监测;超声波检测法定位准确,可作为特高频检测法的补充和辅助手段;2种方法综合利用可有效发现绝缘缺陷并实现准确定位。
文摘对于电力气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)绝缘子沿面放电这类较为常见且严重的局部放电缺陷,目前还没有合适的诊断方法,为此采用振动法进行故障监测和诊断。对采集的GIS振动信号进行小波包分析,发现GIS局部放电的能量主要集中在1.6~6.4kHz频段内;提出用1.6~6.4kHz频段作为特征频段,给出了局部放电特征系数,其定义为1.6~6.4kHz频段的总能量与6.4~12.8kHz频段的总能量的比值;通过观察特征系数的大小,与正常状态下的值进行比较,就可以判断GIS是否发生沿面放电缺陷;并且给出特征系数的阈值范围,对沿面放电严重程度进行划分。研究表明,该方法可以有效诊断GIS沿面放电故障,与其他方法相比,效果比较好。
文摘In this paper, a criterion on the C^0-sufficiency for a function germ with non-isolated singularity is obtained analogously to that of Kuiper-Kuo for the case of isolated singularities. Moreover, the Kuiper Kuo condition and the Thom condition for an analytic function germ with non-isolated singularity are proved to be equivalent.
文摘高电压等级的气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)在发生大电流短路故障时,常常由于短路能量较大,故障设备烧蚀严重而无法确定故障位置和直接原因。针对此,采用扫描电子能谱(energy disperse spectroscopy,EDS)法对发生故障的220 k V某变电站GIS设备SF6气体分解产物及故障区域表面附着物进行分析研究,结合返厂解体,同时考虑断路器设备原件的成分组成,分析了造成事故的原因。同时,在实体220 k V GIS内试验研究了铁质金属颗粒对GIS绝缘强度的影响和绝缘劣化的危险程度。结果表明:GIS断路器内存在铁质金属异物是造成事故的直接原因,厂内安装控制不严造成的带缺陷出厂为间接原因;在同一电压等级下,金属异物越大对GIS的绝缘强度影响越明显,绝缘劣化越突出,GIS越易发生闪络事故。
