Pencil sharpener of 6 cuts and takes practice to master without breaking the lead. Specialized sharpeners are available that operate on non-standard sizes of pencil, such as crayons used in primary schools. Sharpeners that have two openings, one for normal pencils and one for larger crayons, are fairly common. An artist's or draftsman's pencil sharpener leaves the graphite untouched and sharpens only the wood (some models can switch from standard to wood-only by an adjustment). The graphite lead is then honed to a sharp point with a lead pointer, which sharpens only the lead without wood. Lead pointers are also used with
Lead tin telluride Lead tin telluride Lead tin telluride, also referred to as PbSnTe or PbSnTe, is a ternary alloy of lead, tin and tellurium, generally made by alloying either tin into lead telluride or lead into tin telluride. It is a IV-VI narrow band gap semiconductor material. The band gap of PbSnTe is tuned by varying the composition(x) in the material. SnTe can be alloyed with Pb (or PbTe with Sn) in order to tune the band gap from 0.29 eV (PbTe) to 0.18 eV (SnTe). It is important to note that unlike II-VI chalcogenides, e.g. cadmium, mercury and zinc chalcogenides, the