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1.
The results of formation of the high density effective scintillation ceramics consisting of two compounds of the cubic symmetry, LuAG:Ce and Lu2O3 (LuAG:Ce + Lu2O3), are described. Powders of a novel material LuAG:Ce + Lu2O3 were synthesized by co-precipitation method. The introduction of Lu2O3 into LuAG:Ce was shown to increase the density of the ceramics obtained and modify its scintillation properties. 相似文献
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《Ceramics International》2015,41(7):8614-8622
SnO2–ZnO nanocomposite thin films, prepared by a simple carbothermal reduction based vapor deposition method, were irradiated with 8 MeV Si3+ ions for engineering the morphological and optical properties. The surface morphology of the nanocomposites was studied by atomic force microscopy (AFM), while the optical properties were investigated by photoluminescence spectroscopy (PL) and Raman spectroscopy. AFM studies on the irradiated samples revealed growth of nanoparticles at lower fluence and a significant change in surface morphology leading to the formation of nanosheets and their aggregates at higher fluences. A tentative mechanism underlying the observed ion induced evolution of surface morphology of SnO2–ZnO nanocomposite is proposed. PL studies revealed strong enhancement in the UV emissions from the nanocomposite thin film at lower fluence, while a drastic decrease in the UV emissions along with a significant enhancement in the defect emissions has been observed at higher fluences. 相似文献
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An efficient acousto-optic Q-switched Yb-doped Gd3AlxGa5−xO12 (GAGG) (x = 0.5) laser is demonstrated. Under the absorbed pump power of 7.4 W, the maximum average output power of 1.4 W is obtained at the pulse repletion rate of 1 kHz , with the slope efficiency as high as 32%. The pulse width of 40 ns is achieved with the pulse energy and peak power of 1.4 mJ and 35 kW, respectively. What’ more, the output spectrum shows itself tri-wavelength in either CW or Q-switching mode. To our knowledge, this is the first time for realizing simultaneous tri-wavelength Yb:GAGG laser actively Q-switched operation. 相似文献
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《Optical Materials》2005,27(1):99-102
The spin Hamiltonian parameters g∥, g⊥, A∥ and A⊥ for Er3+ ion in LiYF4 are investigated by using the perturbation formulas of these parameters for a 4f11 ion in tetragonal symmetry. In these formulas, the contributions to the spin Hamiltonian parameters from the second-order perturbation terms and the admixtures of different states are considered. The relevant crystal field parameters are calculated from the superposition model and the local structural parameters of the Y3+ site occupied by impurity Er3+. The theoretical optical spectra within 4I15/2 and 4I13/2 states and the spin Hamiltonian parameters obtained in this work are consistent with the observed values. 相似文献
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The Gd substituting effects for La in La0.67Ca0.33MnO3 has been studied .With increasing the substituting amount of Gd,the phase transition temperature of metal-isolator for the samples decreases,the corresponding peak resistivity increases,the Curie temperature decreases monotonically.The substitution of La-Ca-Mn-O with 11% Gd for La improved the magnetoresistance ratio by an order of magnitude.The effects of substituting Gd can be explained in terms of the lattice effects.An irreversible MR behaviour was observed in Gd-substituting compounds.This effect became marked when the substituting amount of Gd was greater than 7%.A maximum irreversible increment of MR ratio as large as 91% was obtained when Gd substituting amount was 11%. 相似文献
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《Materials Letters》2007,61(8-9):1722-1724
We report on the synthesis of nano-porous silicon oxide (SiO2) layers by gas phase polymerisation reactions of hexamethy disiloxane and oxygen. The SiO2 layers are deposited onto one or more layers of poly(methylmethacrylate) (PMMA) particles spin coated onto the substrate surface. Subsequent annealing of the films to high temperature (500 °C) leads to the pyrolysis of the polymeric particles resulting in a 3D nanoporosity in the film. X-ray Photoelectron (XPS) and Fourier Transform Infra Red Spectroscopy (FTIR) show an SiO2-like surface chemistry and virtually complete removal of the organic components. These materials offer a very high surface area-to-volume ratio suitable for sensing applications. 相似文献
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《Materials Chemistry and Physics》2007,101(2-3):329-335
Four new multi-branched two-photon absorption chromophores, namely 1-(4-bromobenzal)-3,5-bis(4-((E)-2-(pyridin-4-yl)vinyl)phenyl)benzene (4), tris(4-((E)-2-(pyridin-4-yl)vinyl)phenyl)-benzene (5), 6-chloro-N2,N4-bis(4-((E)-2-(pyridin-4-yl)vinyl)phenyl)-1,3,5-triazine-2,4-diamine (6), tris-[4-(2-pyridin-4-yl-vinyl)-phenyl]-amine (7), have been synthesized and characterized. One-photon fluorescence, fluorescent quantum yields and two-photon fluorescence have been investigated. The experimental two-photon absorption cross-sections of 4–7 in DMF are 6, 11, 13 GM (pumped by 740 nm laser) and 19 GM (pumped by 800 nm laser), respectively. The calculated two-photon absorption cross-sections of 4–7 are 5.41, 7.67, 9.57 and 76.14 GM, respectively. The two-photon induced fluorescent peak wavelengths of 4–7 in DMF are 421, 425, 474 and 534 nm pumped by 680, 680, 740 and 800 nm laser, respectively. The results show that molecule 7 is a good two-photon absorption fluorophore possessing long two-photon fluorescent lifetime, good fluorescent quantum yield and large two-photon absorption cross-section. The two-photon absorption peak wavelength of molecule 7 is at 800 nm, which is favourable for initiating two-photon photopolymerization. 相似文献