Multi-color long-lasting phosphorescence of rare earth ions in CdSiO3 matrix

A series of rare earth ions doped CdSiO3:RE3+(RE=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) multi-color long-lasting phosphorescence phosphors are prepared by the conventional high-temperature solid-state method. The results of XRD measurement indicate that the products fired under 1050degreesC for 3 h have a good crystallization without any detectable amount of impurity phase. Rare earth ions doped CdSiO3 phosphors possess excellent luminescence properties. When rare earth ions such as Y3+, La3+, Gd3+, Lu3+, Ce3+, Nd3+, Ho3+, Er3+, Tm3+ and Yb3+ are introduced into the CdSiO3 host, one broadband centered at about 420 nm resulting from traps can be observed. In the case of other earth ions such as Pr3+, Sm3+, Eu3+, Tb3+ and Dy3+, their characteristic line emitting as well as the similar to420 nm broadband luminescence can be obtained. The mixture of their characteristic line emitting with the similar to420 nm broadband luminescence results in various afterglow color.

Multi-color long-lasting phosphorescence in Mn2+-doped ZnO-B2O3-SiO2 glass-ceramics

Multi-color LLP phenomenon was observed in Mn2+-doped ZnO-B2O3-SiO2 glassceramics after the irradiation of a UV lamp at room temperature. Transparent ZnO-B2O3-SiO2 glass emitted reddish LLP while opaque glass-ceramics prepared by the glass sample after heat treatment emitted yellowish or greenish LLP. The change of the phosphorescence is due to the alteration of co-ordination state of Mn2+. The phosphorescence of the samples was seen in the dark with naked eyes even 12 h after the irradiation with a UV lamp (lambda(max) = 254 nm) for 30 min. Based on the approximative t(-1) decay law of the phosphorescence, we suggest that the LLP is attributed to the thermally assisted electron-hole recombination.

Measurement of the single-color three-photon resonant ionization spectrum of atomic uranium under the "equivalent wavelength effect laser" interaction

Using Nd: YAG laser (532 nm) pumped mixed-dye laser. we obtained the output of this dye enhanced at the wavelength interval equivalent to that given by the copper vapor laser pumped dye laser. This measure favored is with the measurement of single-color three-photon resonant ionization spectrum of atomic uranium in the range of 562-586 nm,which is otherwise not efficiently covered by Nd: YAG laser pumped dye laser with any single dye. Thus 140 U I energy levels were obtained and the peaks of interest 575.814 nm and 575.836 rim were well resolved and their relative intensity determined.

Study of color centers and trace oxygen in KMgF3 : Eu single crystal

Using the Bridgeman-Stockbarger method, the KMgF3:EU2+ single crystal was grown. The color centers in unirradiated KMgF3:Eu crystal were studied. By thermal annealing, we confirmed the 422-nm emission resulted from color centers and oxygen centers, and we proved the energy transfer from EU2+ to color centers. From spectra, the relative oxygen content in crystal was calculated, and the relationships of oxygen displacing fluorine were studied.

Prediction of molar absorptivities of color reagents and their color reactions with yttrium by artificial neural networks

The new topological indices A(x1)-A(x3) suggested in our laboratories were applied to the study of structure-property relationships between color reagents and their color reactions with yttrium. The topological indices of twenty asymmetrical phosphone bisazo derivatives of chromotropic acid were calculated. The work shows that QSPR can be used as a novel aid to predict the molar absorptivities of color reactions and in the long term to be helpful tool in-color reagent design. Multiple regression analysis and neural network were employed simultaneously in this study. The results demonstrated the feasibility and the effectiveness of the method.

Color filters with negative birefringence for liquid crystal display use

We have developed a special color film with negative birefringence, which can work as a color filter and a viewing angle extension film for liquid crystal displays (LCDs). A high-performance polyimide (PI), which can be dissolved in the usual organic solvent and shows negative birefringence after lamination, was synthesized to fabricate the film. By mixing PI with suitable proportions of green, blue or red pigment in the solvent, then laminating them onto a glass substrate, we obtained color films with good transmission spectra and suitable chromatic coordinates. The results of our experiments show that the color filters still have negative birefringence but a little lower than that of the pure PI film. and can therefore work as compensation films for normal white twist nematic liquid crystal displays (TN-LCD).

Red color filter in an organo-soluble polyamide matrix for liquid crystal displays

A red color filter was laminated from a solution of red color pigment and an organo-soluble polyamide, based on 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) and 2,2'-dimethyl-4,4'-methylene dianiline (DMMDA). The red color filter in a polyamide matrix with negative birefringence plays an important role in twisted nematic liquid crystal displays (TN-LCDs). The red color filter, and also compensation films, extend the viewing angle of LCDs. (C) 1997 Elsevier Science S.A.

Prediction of molar absorptivities of color reagents during their color reactions with cerium using multiple regression analysis and neural network

A quantitative structure-property study has been made on the relationship between molar absorptivities (epsilon) of asymmetrical phosphone bisazo derivatives of chromotropic acid and their color reactions with cerium by multiple regression analysis and neural network. The new topological indices A(x1) - A(x3) suggested in our laboratory and molecular connectivity indices of 43 compounds have been calculated. The results obtained from the two methods are compared. The neural network model is superior to the regression analysis technique and gave a prediction which was sufficiently accurate to estimate the molar absorptivities of color reagents during their color reactions with cerium.

Study on structure-property relationships between color reagents and sensitivity of color reactions with yttrium by topological indices

In this paper, three topological indices, Am-1, Am-2, and Am-3, multivariate analysis in structure-property studies. The topological indices of twenty asymmetrical phosphosphono bisazo derivatives of chromotropic acid have been calculated. The structure-property relationships between color reagents and molar absorptivity of color reactions with yttrium have been studied by A(m) indices and structure selective factors. Good results have been obtained by using correlation equation to predict the molar absorptivity of new color reagents.

Studies on structure-property relationship between color reagents and contrast of their color reactions with cerium by topological indices

In this paper, three topological indices A(m1), A(m2) and A(m3) have been applied to multivariate analysis in structure property relationship studies. The topological indices oi fourty-three asymmetrical phosphono bisazo derivatives of chromotropic acid have been calculated, The structure-property relationship between color reagents and contrast of color reactions with cerium has been studied by A, indices and structure selective factors, Good results have been obtained.

STUDIES ON STRUCTURE-PROPERTY RELATIONSHIP BETWEEN COLOR REAGENTS AND SENSITIVITY OF THEIR COLOR-REACTIONS WITH YTTERBIUM BY TOPOLOGICAL INDEXES

In this paper A, topological indices and molecular connectivity inidces have been applied to multivariate analysis in structure-property studies. The topological indices of twenty asymmetrical phosphone bisazo derivatives of chromotropic acid have been calculated. The structure-property relationships between color reagents and molar absorptivity of color reactions with ytterbium have been studied by A(m) indices and molecular connectivity indices. Good results have been obtained.

A NOVEL SHELL COLOR VARIANT OF THE PACIFIC ABALONE HALIOTIS DISCUS HANNAI INO SUBJECT TO GENETIC CONTROL AND DIETARY INFLUENCE

Molluscan shells may display a variety of colors, which formation, inheritance, and evolutionary significance are not Well understood. Here we report a new variant of the Pacific abalone Haliotis discus hannai that displays a novel orange shell coloration (O-type) that is clearly distinguishable from the Wild green-shelled abalone (G-type). Controlled mating experiments between O- and G-type abalones demonstrated apparent Mendelian segregations (1:1 or 3:1) in shell colors in F-2 families, which support the notion that the O- and G-types are under strict genetic control at a single locus With a recessive o (for orange shell) allele and a dominant G (for green shell) allele. Feeding with different diets caused modifications of shell color within each genotype, ranging from orange to yellow for O-type and green to dark-brown for the G-type, without affecting the distinction between genotypes. A previously described bluish-purple (B-type) shell color was found in one of the putative oo X oG crosses, suggesting that the B-type may be it recessive allele belonging to the same locus. The new O-type variant had no effect on the growth of Pacific abalone on the early seed-stage. This Study demonstrates that shell color in Pacific abalone is subject to genetic control as well as dietary modification, and the latter probably offers selective advantages in camouflage and predator avoidance.