Papers by Author: Lan Luo

Abstract: Near-infrared emission properties of Dy3+-Tm3+ co-doped Ge-Ga-Sb-Se glasses were investigated. Possible energy transfer routes and the regime of donor decay were discussed. Tm3+ is found to be an efficient sensitizer on the Dy3+:1.34μm luminescence. Probable energy transfer schemes include Tm3+:3H4 → Dy3+: 6F5/2 and Tm3+:3H5 → Dy3+:6F11/2· 6H9/2. The donor (Tm3+) excitation is transferred to an acceptor (Dy3+) by direct interaction or migrates among donors by diffusion-limited regime until it comes into the vicinity of an energy acceptor where direct interaction and transfer occur.

Abstract: In this study, 2BaO-3B2O3 (BB) glass was used as a sintering aid to lower the sintering temperature of Ba2Ti9O20 ceramics. Microwave Characteristics of the BB-added Ba2Ti9O20 ceramics sintered at different temperatures were investigated. The crystalline phases of BB-Ba2Ti9O20 ceramics are Ba2Ti9O20, BaTi(BO3)2 and TiO2. Good microwave dielectric properties (εr = 26, Q*f = 28770GHz and τf = 14.6ppm/oC) were obtained by sintering the BB-added Ba2Ti9O20 ceramics at 1040oC for 2 h.

Abstract: (1-x)La2/3TiO3-xLa(Mg1/2Ti1/2)O3 ceramics with x ranging from 0.01 to 0.3 were prepared by the conventional solid-state reaction method. Microstructure and microwave dielectric properties were studied. The perovskite compound La2/3TiO3 is stabilized when x = 0.1. The content of La2/3TiO3 increases with increasing x from 0.01 to 0.1, and thereafter decreases when x > 0.1. The same tendency was also observed on measuring the dielectric constant, temperature coefficient of resonant frequency and Q× ƒ. A maximum permittivity of 77.35 was achieved with these stabilized La2/3TiO3 ceramics. Close to zero τf value (1 ppm/°C) was obtained at x=0.3, but its Q× ƒ value was relative low.