The monodisperse silica particles self-assembled colloidal crystals were used as templates to synthesize pH value and temperature responsive ordered macorporous hydrogels. The ordered structure arranged by the uniform...The monodisperse silica particles self-assembled colloidal crystals were used as templates to synthesize pH value and temperature responsive ordered macorporous hydrogels. The ordered structure arranged by the uniform pores and the pore-pore interconnectivity through the window channel is confirmed by SEM characterization. UV-Vis-near IR absorption experiment result reveals that the wavelength at the stop band peak is tunable within the whole visible spectrum via simply altering some parameters such as pH value and light incidence angle. This finding allows to design frequency-tunable photonic band gap materials.展开更多
Eu3+ activated CaWO4 was prepared by high temperature solid state reaction technique. Red afterglow was observed for in the CaWO4∶Eu after exciting with 254 nm light due to Eu3+ transition from 5D0 to 7FJ (J=0, 1, 2,...Eu3+ activated CaWO4 was prepared by high temperature solid state reaction technique. Red afterglow was observed for in the CaWO4∶Eu after exciting with 254 nm light due to Eu3+ transition from 5D0 to 7FJ (J=0, 1, 2, 3,4). By the cal culation of the thermoluminescence spectrum of CaWO4∶Eu, we conclude that there were two types of trap centers: VCa″ was formed by substitution of Ca2+ by Eu3 + and complex traps were produced because of substitution of W6+ by Eu3+.展开更多
The new Er3+, Ho3+ and Tm3+ doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. Th...The new Er3+, Ho3+ and Tm3+ doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. The excitation and photoluminescence spectra, afterglow spectra and afterglow decay curve were examined by fluorescence spectroscopy. The afterglow spectra of Gd2O2S∶Er3+, Mg, Ti showed typical transitions of Er3+ at 528 (2H11/2 → 4I15/2),548 (4S3/2 → 4I15/2) and 669 nm (4F9/2 → 4I15/2). In the afterglow spectra of Gd2O2S∶ Ho3+, Mg, Ti, typical transitions of Ho3+ at 546 nm (5S2 → 5I8), 651 and 661 nm (5F5 → 5I8) were observed. In Gd2O2S∶Tm3+, Mg, Ti, the afterglow emission at 800 nm (1G4 → 3H5) of Tm3+ was seen. The mechnism and model of afterglow energy transfer were proposed.展开更多
A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium com...A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium complexes[(dbm) 3Ti(OPh)/MAO] catalyzed polymerization of styrene was carried out to form syndiotactic polystyrene(sPS)/silica composites. The titled ordered macroporous syndiotactic polystyrene was achieved by chemical decomposition of the silica template with concentrated aqueous hydrofluoric acid, which was confirmed by SEM results. FTIR spectra indicated that all silica was removed from the composites in this study. DSC revealed that the as prepared macroporous sPS was significantly different from the bulk one, and the unique properties were inherent rather than from the enforcement effect by the silica template. Further investigation concerning the inherent microstrucutures about the molecular weight and its distribution, tacticity of the styrene etc . and their dependence on the confinement is in progress.展开更多
Nano-titania was prepared by microwave heating hydrolysis.And the effects of microwave heating hydrolysis on the TiO2 size,morphology and crystal phase were studied by means of orthogonal experiment,XRD,TEM and IR.The...Nano-titania was prepared by microwave heating hydrolysis.And the effects of microwave heating hydrolysis on the TiO2 size,morphology and crystal phase were studied by means of orthogonal experiment,XRD,TEM and IR.The transforming temperature from anatase to rutile of titania prepared by microwave heating hydrolysis was above 800℃.展开更多
文摘The monodisperse silica particles self-assembled colloidal crystals were used as templates to synthesize pH value and temperature responsive ordered macorporous hydrogels. The ordered structure arranged by the uniform pores and the pore-pore interconnectivity through the window channel is confirmed by SEM characterization. UV-Vis-near IR absorption experiment result reveals that the wavelength at the stop band peak is tunable within the whole visible spectrum via simply altering some parameters such as pH value and light incidence angle. This finding allows to design frequency-tunable photonic band gap materials.
文摘Eu3+ activated CaWO4 was prepared by high temperature solid state reaction technique. Red afterglow was observed for in the CaWO4∶Eu after exciting with 254 nm light due to Eu3+ transition from 5D0 to 7FJ (J=0, 1, 2, 3,4). By the cal culation of the thermoluminescence spectrum of CaWO4∶Eu, we conclude that there were two types of trap centers: VCa″ was formed by substitution of Ca2+ by Eu3 + and complex traps were produced because of substitution of W6+ by Eu3+.
文摘The new Er3+, Ho3+ and Tm3+ doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. The excitation and photoluminescence spectra, afterglow spectra and afterglow decay curve were examined by fluorescence spectroscopy. The afterglow spectra of Gd2O2S∶Er3+, Mg, Ti showed typical transitions of Er3+ at 528 (2H11/2 → 4I15/2),548 (4S3/2 → 4I15/2) and 669 nm (4F9/2 → 4I15/2). In the afterglow spectra of Gd2O2S∶ Ho3+, Mg, Ti, typical transitions of Ho3+ at 546 nm (5S2 → 5I8), 651 and 661 nm (5F5 → 5I8) were observed. In Gd2O2S∶Tm3+, Mg, Ti, the afterglow emission at 800 nm (1G4 → 3H5) of Tm3+ was seen. The mechnism and model of afterglow energy transfer were proposed.
文摘A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium complexes[(dbm) 3Ti(OPh)/MAO] catalyzed polymerization of styrene was carried out to form syndiotactic polystyrene(sPS)/silica composites. The titled ordered macroporous syndiotactic polystyrene was achieved by chemical decomposition of the silica template with concentrated aqueous hydrofluoric acid, which was confirmed by SEM results. FTIR spectra indicated that all silica was removed from the composites in this study. DSC revealed that the as prepared macroporous sPS was significantly different from the bulk one, and the unique properties were inherent rather than from the enforcement effect by the silica template. Further investigation concerning the inherent microstrucutures about the molecular weight and its distribution, tacticity of the styrene etc . and their dependence on the confinement is in progress.
文摘Nano-titania was prepared by microwave heating hydrolysis.And the effects of microwave heating hydrolysis on the TiO2 size,morphology and crystal phase were studied by means of orthogonal experiment,XRD,TEM and IR.The transforming temperature from anatase to rutile of titania prepared by microwave heating hydrolysis was above 800℃.
