为确定500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)与其周边公众移动通信(Public Mobile Telecommunications,PMT)系统的电磁兼容(electromagnetic compatibility,EMC)特性,本文综合论述了F...为确定500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)与其周边公众移动通信(Public Mobile Telecommunications,PMT)系统的电磁兼容(electromagnetic compatibility,EMC)特性,本文综合论述了FAST宁静区内中国移动、中国联通和中国电信三大运营商所属PMT基站对其产生的电磁干扰。首先,从射电天文业务的频谱划分谈起,论述了射电天文业务干扰源类型,引出了其运行保护标准,进而针对FAST详细说明了FAST宁静区的用频法规和保护要求;其次,分析了ITU-R建议电波传播预测与干扰分析方法,并通过实地测量验证了该方法的适用性,进一步针对性地分析了PMT基站的电磁辐射传播特性,综合评估了FAST宁静区内PMT基站的干扰情况:FAST宁静区域90.24%的PMT基站在一定程度上均会对FAST产生干扰,而在所选分析条件下,仅有43.14%的数据符合FAST保护要求;最后,针对PMT基站干扰信号的抑制和消除,分析了常用的射电天文射频干扰抑制方法,同时为保障FAST免受PMT基站干扰,从FAST和PMT基站的角度出发论述了可行的用频防护措施,并基于实施难度、经济成本、策略收益和通信质量4类指标建立了防护方法的评估体系,对所提防护方法进行了实例说明。上述研究成果可为保障FAST的安全观测提供技术基础。展开更多
In this study,we present the large photomultiplier tube(PMT)afterpulse measurement results obtained from the Jiangmen underground neutrino observatory(JUNO)experiment.A total of 11 dynode-PMTs(R12860)from the Hamamats...In this study,we present the large photomultiplier tube(PMT)afterpulse measurement results obtained from the Jiangmen underground neutrino observatory(JUNO)experiment.A total of 11 dynode-PMTs(R12860)from the Hamamatsu company(Hamamatsu Photonics K.K.(HPK))and 150 micro-channel plate PMTs(MCP-PMTs,GDB-6201)from the NNVT company(North Night Vision Technology Co.,Ltd.(NNVT))were tested.Subsequently,an afterpulse model was built according to the afterpulse time distribution and the probability of occurrence for these two types of PMTs.The average ratio of the total afterpulse charge with a delay between 0.5μs and 20μs to the primary pulse charge is∼5.7%(13.2%)for the tested MCPPMTs(dynode-PMTs).The JUNO experiment will deploy 20,01220-inch PMTs;this study will benefit detector simulation,event reconstruction,and data analysis regarding the JUNO experiment.展开更多
目的研究蛋白质-O-甘露糖转移酶-2(PMT2)基因对酿酒酵母复制性寿命的影响。方法依据基因同源重组原理,构建PMT2基因缺失(pmt2)或基因过表达(PMT2-ox)酵母菌株;实时定量PCR验证菌株中PMT2基因转录水平;显微镜下分离和计数酵母子细胞数目...目的研究蛋白质-O-甘露糖转移酶-2(PMT2)基因对酿酒酵母复制性寿命的影响。方法依据基因同源重组原理,构建PMT2基因缺失(pmt2)或基因过表达(PMT2-ox)酵母菌株;实时定量PCR验证菌株中PMT2基因转录水平;显微镜下分离和计数酵母子细胞数目,检测酵母细胞的复制性寿命。结果成功构建PMT2基因缺失或过表达酵母菌株,实时定量PCR证明PMT2 m RNA在pmt2菌株中无表达,在PMT2-ox菌株中表达上调。与野生型酵母细胞的平均寿命(约23代)比较,pmt2菌株的寿命为(25.2±8.9)代,PMT2-ox菌株的寿命为(24.1±7.3)代,寿命无明显延长(P>0.05)。结论酿酒酵母PMT2基因不参与复制性寿命的调控。展开更多
文摘为确定500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)与其周边公众移动通信(Public Mobile Telecommunications,PMT)系统的电磁兼容(electromagnetic compatibility,EMC)特性,本文综合论述了FAST宁静区内中国移动、中国联通和中国电信三大运营商所属PMT基站对其产生的电磁干扰。首先,从射电天文业务的频谱划分谈起,论述了射电天文业务干扰源类型,引出了其运行保护标准,进而针对FAST详细说明了FAST宁静区的用频法规和保护要求;其次,分析了ITU-R建议电波传播预测与干扰分析方法,并通过实地测量验证了该方法的适用性,进一步针对性地分析了PMT基站的电磁辐射传播特性,综合评估了FAST宁静区内PMT基站的干扰情况:FAST宁静区域90.24%的PMT基站在一定程度上均会对FAST产生干扰,而在所选分析条件下,仅有43.14%的数据符合FAST保护要求;最后,针对PMT基站干扰信号的抑制和消除,分析了常用的射电天文射频干扰抑制方法,同时为保障FAST免受PMT基站干扰,从FAST和PMT基站的角度出发论述了可行的用频防护措施,并基于实施难度、经济成本、策略收益和通信质量4类指标建立了防护方法的评估体系,对所提防护方法进行了实例说明。上述研究成果可为保障FAST的安全观测提供技术基础。
基金supported by Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA10011100),Joint Institute of Nuclear Research (JINR),Russia and Lomonosov Moscow State University in Russia,joint Russian Science Foundation (RSF),DFG (Deutsche Forschungsgemeinschaft)National Natural Science Foundation of China (Nos. 12090062 and 12075087)
文摘In this study,we present the large photomultiplier tube(PMT)afterpulse measurement results obtained from the Jiangmen underground neutrino observatory(JUNO)experiment.A total of 11 dynode-PMTs(R12860)from the Hamamatsu company(Hamamatsu Photonics K.K.(HPK))and 150 micro-channel plate PMTs(MCP-PMTs,GDB-6201)from the NNVT company(North Night Vision Technology Co.,Ltd.(NNVT))were tested.Subsequently,an afterpulse model was built according to the afterpulse time distribution and the probability of occurrence for these two types of PMTs.The average ratio of the total afterpulse charge with a delay between 0.5μs and 20μs to the primary pulse charge is∼5.7%(13.2%)for the tested MCPPMTs(dynode-PMTs).The JUNO experiment will deploy 20,01220-inch PMTs;this study will benefit detector simulation,event reconstruction,and data analysis regarding the JUNO experiment.
文摘目的研究蛋白质-O-甘露糖转移酶-2(PMT2)基因对酿酒酵母复制性寿命的影响。方法依据基因同源重组原理,构建PMT2基因缺失(pmt2)或基因过表达(PMT2-ox)酵母菌株;实时定量PCR验证菌株中PMT2基因转录水平;显微镜下分离和计数酵母子细胞数目,检测酵母细胞的复制性寿命。结果成功构建PMT2基因缺失或过表达酵母菌株,实时定量PCR证明PMT2 m RNA在pmt2菌株中无表达,在PMT2-ox菌株中表达上调。与野生型酵母细胞的平均寿命(约23代)比较,pmt2菌株的寿命为(25.2±8.9)代,PMT2-ox菌株的寿命为(24.1±7.3)代,寿命无明显延长(P>0.05)。结论酿酒酵母PMT2基因不参与复制性寿命的调控。
