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   51092
   We propose to observe the whole of the Cygnus Loop supernova remnant.
   It allows us to investigate the spatial distribution of the electron
   temperature and metal abundances. Due to the homogeneities of the
   interstellar medium around the Cygnus Loop, this observation can prove
   the nucleosynthesis in the supernova explosion and its diffusion into
   the interstellar medium.
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