Unexpected luminescence of Cr5+ and Cr3+ ions in ZrSiO4 zircon crystals

Luminescence, decay-times and EPR spectroscopy of Cr-doped ZrSiO4 show the presence of both Cr3+ and Cr5+ active centers, which can be connected with Zr4+ and Si4+ adjacent two-cation replacement. Cr5+ emission occurs within a similar spectral range as for Cr4+ and hence confusion is possible

IR Bismuth active centers in optical fibers: Combined excitation-emission spectroscopy

3D excitation-emission luminescence spectra of Bi-doped optical fibers of various compositions were measured in a wide wavelength range 450-1700 nm. Such luminescence spectra were obtained for Bi-doped pure silica and germania fibers, and for Bi-doped Al- or P-codoped silica fibers (at room and liquid nitrogen temperatures). The energy level schemes of IR bismuth active centers in pure silica and germania core fibers were derived from spectra obtained. The energy level schemes similarity of bismuth active centers in these two types of fibers was revealed.Comment: 12pages, 7 figures, 5 table

METHOD FOR THE BEST SOLUTIONS SEARCH IN MULTIOBJECTIVE DECISION PROBLEMS

This paper describes a method for con structing a decision rule providing the isolation of the most preferable soluti ons in multiobjective decision problems. The method is based on the iterative procedure for constructing decision rules. Criteria of meaning-fulness and consistency of received information are formulated. The results are given of applying the method to solution of the most preferable alternatives searc