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Abstract. A discontinuous volume change was observedon the Hugoniot curve of corundum (c•-A1203) along the axis by the inclined-mirror streak photographic technique, probably due to a high-pressure phase transformation. The transition pressure was measured to be 79 GPa, where shock temparature was estimated to be 860øC, in good agreement with a fully optimized quantum mechanical calculation. The volume change at the transition point was considered to be larger than 3 %, which was largerthan the theoretically predicted value of the corundumRh203 (II) transition, and was consistent with the recent static compression result by using diamond-anvil cell. The occurence of the phase transformation in alumina under shock compression presents significant implication in earth interior science or ceramic science, and also seriously affects the interpretation of static and shock compresion experiments at ultra-high pressures.

It had been reported that for potassium chloride (KCl) the B1-B2 phase transition (PT) occurs under shock and static compressions, but the measured transition points showed large scatter. In this study, Hugoniot measurement experiments were performed on KCl single crystals by the inclined-mirror method combined with use of a powder gun. The anisotropic Hugoniot elastic limits and PT points were observed. The PT points along the 100 , 110 and 111 axis directions were determined as 2.5, 2.2 and 2.1 GPa, respectively. The anisotropic transition was reasonably explained in terms of the displacement mechanism along the 111 axis direction.

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Die Aniline (I) reagieren mit den Methylpyridinen bzw. 2‐Methylchinolin (II) in Gegenwart von Schwefel zu den Benzothiazolen (III).