This paper makes a brief discussion on the harm upon human health by radio-frequency electromagnetic field and electromagnetic contamination problems of small power television emission antenna.
本文就射频电磁场对人体健康的危害以及小功率电视发射天线的电磁污染问题作了简要的论述。
It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951; it must be known to any kind of radio astronomer in the universe.
它是人们于1951年发现的太空氢原子的天然发射频率，宇宙间任何一种射电天文学家都必定知道它。
It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951; it must be known to any kind of radio astronomer in the universe.
它是人们于1951年发现的太空氢原子的天然发射频率，宇宙间任何一种射电天文学家都必定知道它。
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