这次爆炸，其爆炸能量估计相当于约1500万吨的TNT，广泛认为是由跨度为数十米的一颗流星在半空中爆炸所造成的。
The blast, which has been estimated at the equivalent of around 15 megatons of TNT is widely thought to have been caused by a meteor a few tens of metres across exploding in mid-air.
本龙门焊机是为焊制几十米长的大型箱式结构件而研制的弧焊设备。
This gantry type welding machine is an arc welding equipment developed for welding large box type construction of tens meters long.
文中所作的主要工作是为云南天文台十米抛物面设计、制造一付好的对数周期偶极子天线（LPDA）作馈源。
The major work of this thesis is to design and make a good LPDA(log-periodic dipole antenna)as the feed of the ten-meter parabolic reflectors at the Yunnan Observatory.
文中所作的主要工作是为云南天文台十米抛物面设计、制造一付好的对数周期偶极子天线（LPDA）作馈源。
The major work of this thesis is to design and make a good LPDA(log-periodic dipole antenna)as the feed of the ten-meter parabolic reflectors at the Yunnan Observatory.
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