Current , identification silicon

Phase transformations in semiconductors, including pressure-induced metallization, have been described in this review. Currently, only silicon has been studied thoroughly enough. However, even for this simple elemental semiconductor, not all issues concerning identification of new phases, transformations mechanisms, and transformation paths have been resolved. 

The natural occurrences of montmorillonites are varied and complex, as is the mineralogy of this mineral group. They are particularly variable chemically, due in part to the completely undefined interlayer ion position which can be occupied in part or entirely by almost any cation except silicon. Definitions and descriptions of these expandable minerals are necessarily vague since the response of these interlayer ions to different chemical and thermal treatments is the most current method of identification for minerals in the group. This leaves the basic 2 1 structure identified in many cases. A broad differentiation of the basic... 

Combined gas chromatography - mass spectrometry (GC-MS). An LKB 9000 combined GC-MS fitted with an 2.4 m siliconized glass column (2.5 mm I.D.) packed with 1% W-98 silicone gum rubber on Gas Chrom Q was used for the separation and identification of urinary, biliary and circulating metabolites. Structures of all primary metabolites were confirmed by comparison of fragmentation patterns with those obtained from synthesized authentic compounds. The GC column was maintained isothermally at 150°, the GC flash heater and MS separator were maintained at 200°. The ionization potential and trap current were 70 eV and 60 yA respectively. 

Despite the progress made in the field in the last three decades there is currently no single reliable, rapid and experimentally robust method for the forensic identification and discrimination of complex, chemically similar silicone elastomers. There are, however, non-spectroscopic methods available that may be developed to serve such a function. 

---