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   PR # 11170
      We propose to observe two double clusters of galaxies, A1750 and
    A2440,to study dynamical evolution of clusters. A1750 and A2440 have
    two large subclusters, which will merge into single regular clusters.
    In this process, most of the gravitational energy is converted to
    kinetic energy; temperature and luminosity of the cluster will
    increase rapidly. The ASCA observation will provide the density
    distribution, the temperature, and the heavy element abundance of the
    premerging subclusters. These are important information to constrain
    the hierarchical clustering models.



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