Sharp Particle Research Articles

The mathematical structure of the bardeen-cooper-schrieffer model

The BCS-model for an infinitely extended superconductor is analysed mathematically. The reason why the model is solvable becomes evident in the present formulation. It is shown that the ground states with unsharp particle number belong to irreducible representations, those with sharp particle number to reducible representations of the basic operator algebra. The connection between uniqueness of the ground state, irreducibility and linked cluster decomposition is reviewed.

Expeditious method of dissolving Amber and Copal

Synthesis of the yttrium oxysulfide red phosphor by the flux fusion method was presented. Effects of flux compositions and sintering conditions on the shape and size distribution of phosphor were studied. In addition, the optimization of firing conditions was also conducted. After firing phosphor with a flux containing (S+Na2CO3+Li3PO4+K2CO3)/(S+Li2CO3+K2CO3) at a ratio of 3:1 at 1150°C for 2.5 h, Y2O2S:Eu3+ phosphor was obtained without any Y2O3 as a second phase. The nearly spherical phosphor powder exhibited a mean particle size of 3 μm and a rather sharp particle size distribution. Y2O2S:Eu3+ red phosphor illuminated the most red color light with an applied probe current density of 0.51 μA/cm2.