Detailed investigations of the microstructural properties of SrGa2S4:Ce3+ thin films grown by deposition from binary vapors (DBV) were carried out by X-ray diffraction analysis (XRD), energy dispersive X-ray diffraction measurements (EDX), electron probe microanalysis (EPMA), and X-ray photoelectron spectroscopy (XPS) depth profiling. The results indicate uniform distribution of the constituent elements in the nearly stoichiometric structure of the thin films. Photoluminescence (PL) data including absorption and luminescence spectra in the temperature range of 10 to 300 K and decay characteristics show that an increase in Ce concentration from 0.2 to 3 mol% is accompanied with a marked increase in both the intensity of activator absorption and decay time, while the emission and excitation bands remain fixed in position. A mechanism involving the concentration-dependent interactions between different centers in the lattice is proposed, which may explain the experimentally observed behavior.

For vacuum-UV (VUV) phosphor application such as plasma display panels (PDPs) and mercury free lamps, CaAl2O4:Eu2+ (CA:Eu2+) showing 440 nm blue emission was examined. A single phase CA:Eu2+ was obtained by two step firing technique. The photoluminescence (PL) spectrum shows blue shift compared to that of blue-emitting BaMgAl10O17:Eu2+ (BAM:Eu2+) phosphors. CA:Eu2+ phosphors with β-tridymite crystal structure show less luminance degradation on baking in comparison to the commercial BAM:Eu2+ phosphors under VUV excitation. The initial PL intensity of CA:Eu2+ (Eu: 2 mol%) powder phosphor excited by 147 nm light was found to be about 60% of the commercial BAM:Eu2+ and the luminance of test panel with CA:Eu2+ (Eu: 1 mol%) was 37.4 cd/m2. The low test panel luminance with CA:Eu2+ phosphor is partly caused by the poor spread characteristics of the phosphor slurry due to the large particle size distribution. With improvement of luminance efficiency and the powder characteristics, there is a possibility that CA:Eu2+ phosphors can be applied for PDPs.

A blue-light-emitting Eu2+ doped CaMgSi2O6 phosphor with a long lifetime for a plasma display panel (PDP) was developed. The CaMgSi2O6:Eu2+(CMS:Eu2+) phosphors synthesized using SiO2-rich source materials show no luminance degradation during the baking process for binder burn-off, and the photoluminescence peak intensity of the Eu2+ emission band is higher than that of conventional blue phosphor BaMgAl10O17:Eu2+ (BAM) after the baking process. The test PDP using synthesized CMS:Eu2+ phosphor shows a comparable emission peak intensity to that of BAM, while the luminance of the CMS:Eu2+ panel is approximately 55% that of the BAM panel due to the narrower spectral bandwidth and shorter peak wavelength. The CMS:Eu2+ panel shows less luminance degradation than BAM under the aging test, and the CMS:Eu2+ panel retains 85% of its luminance after 300 hours driving. It is found that CMS:Eu2+ appears to be a promising blue phosphor material for PDP.

There has been much interest in building corporate private communication networks. This aim requires a method that optimizes the economical aspect of network configurations. The authors propose a network design method supported by knowledge-base. This method is used to design a cost-effective corporate communication network, using leased lines. The knowledge-base description depends on the production rule. The network configuration is improved by introducing expert knowledge, after designing the network by a conventional algorithm. Design results show the advantages of the proposed method.