نتایج جستجو برای: platinum group elements
تعداد نتایج: 1249980 فیلتر نتایج به سال:
Platinum group elements (PGEs) occur mainly in basic–ultrabasic igneous rocks and are concentrated by the differentiation crystallization of magma. Thin polymetallic layers including Ni, Mo, V, PGEs, rare-earth widely developed lower Cambrian black shales southern China. The PGE contents such may not be economically significant but still unusually enriched. enrichment mechanisms have been studi...
this thesis basically deals with the well-known notion of the bear-invariant of groups, which is the generalization of the schur multiplier of groups. in chapter two, section 2.1, we present an explicit formula for the bear-invariant of a direct product of cyclic groups with respect to nc, c>1. also in section 2.2, we caculate the baer-invatiant of a nilpotent product of cyclic groups wuth resp...
Understanding of the geochemistry of the chalcophile elements [i.e., Os, Ir, Ru, Pt, Pd (platinum-group elements), and Au, Cu, Ni] has been informed for at least 20 years by the common assumption that when crust-forming partial melts are extracted from the upper mantle, sulfide liquid in the restite sequesters chalcophile elements until the extent of partial melting exceeds approximately 25% an...
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