Crystalline-phase-dependent red emission behaviors of Gd2O3:Eu3+ thin-film phosphors

Gd₂O₃:Eu³⁺ luminescent thin films have been grown on Al₂O₃(0001) substrates using pulsed-laser deposition. The films grown at different deposition conditions showed different crystalline phases, surface morphologies and luminescent characteristics. Both cubic and monoclinic crystalline phases were observed for the Gd₂O₃:Eu³⁺ films, and the crystalline structure and the surface morphology of the films were highly dependent on the oxygen pressure and substrate temperature. The cubic system showed a higher luminescence than the monoclinic system. The luminescence characteristics were strongly influenced by not only the crystalline structure but also the surface morphology of the films. The photoluminescencebrightness data obtained from Gd₂O₃:Eu³⁺ films indicate that Al₂O₃(0001) is a promising substrate for growth of high-quality Gd₂O₃:Eu³⁺ thin-film red phosphor. In particular, the Gd₂O₃:Eu³⁺ films showed a much better photoluminescence behavior than a Y₂O₃:Eu³⁺ films with the same thickness. PACS 78.20.-e; 78.55.-m; 78.66.-w     

Fuzzyn-fold positive implicative filters in lattice implication algebras

The fuzzification of a positive implicative filter is considered, and some of properties are investigated. The relation among fuzzy filter, fuzzyn-fold implicative filter, and fuzzyn-fold positive implicative filter is discussed.     

An orbifold compactification with three families from twisted sectors

We obtain a three generational SU(3)_c×SU(3)_w×U(1)⁴×[SO(12)×U(1)²]′ model from an orbifold construction with the requirement that three generations arise from twisted sectors. There exist supersymmetric vacua realizing the standard model. In one example the anomalous U(1) breaks the gauge symmetry down to SU(3)_c×SU(3)_w×U(1)_y×SO(12)′.     

On fuzzy BCK-filters

In [6], Y. B. Jun et al. fuzzified the concept of BCK-filters in BCK-algebrs, and investigated its properties. In this paper, we investigate further properties of fuzzy BCK-filters.     

On fuzzy B-algebras

The fuzzification of (normal) B-subalgebras is considered, and some related properties are investigated. A characterization of a fuzzy B-algebra is given.     

Sol-gel transition of polyacrylonitrile/propylene carbonate solution

The thermoreversible gelation of polyacrylonitrile (PAN)/propylene carbonate (PC) solution was investigated by calorimetric, thermomechanical, optical, and rheological measurements. Two endothermic signals are observed for PAN/PC gels in DSC thermograms, and the peak temperature of the higher melting endotherm coincides with the gel melting temperature determined from the TMA thermogram. SEM micrographs show that the overall structure is separated into two phases and is composed of sperical domains, which may be formed upon passing through the thermodynamically unstable or metastable state via the liquid-liquid phase separation. The gelation rate increases with the aging temperature. This is also discussed on the basis of the elasticity theory of the fishnet gel. © 1994 John Wiley & Sons, Inc.     

A new efficient and practical synthesis of 2-deoxy-l-ribose

An efficient and practical route for large-scale synthesis of 2-deoxy-l-ribose starting from l-ascorbic acid was developed in eight steps without chromatographic purification for all intermediates. Additionally, (2S,3R)-3,4-epoxy-1,2-O-isopropylidenebutane-1,2-diol, a versatile intermediate in carbohydrate synthesis, was also prepared readily in excellent yield as a key intermediate.