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    PR # 31233                                                                   
     It is widely accepted that merging clusters are in an intermediate st       
     age in the course of cluster of galaxies. Some X-ray observations sho       
     w that the cooling flows are not seen in the clusters with substructu       
     re  although cooling flow are considered to be common phenomena among       
      clusters of galaxies. This suggests that the cooling flow becomes mo       
     re significant as the merging proceds. However the details of the evo       
     lution of the cooling flow are poorly understood because of the limit       
     ed energy range of previous Xray imaging observation. We propose to o       
     bserve several merging clusters in order to investigate the early sta       
     ge of clusters evolution by means of measuring the surface brightness       
      and temperature distribution using the wide enrgy range and the spat       
    ial resolution of ASCA.                                                      
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