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1.
Multicomponent telluride-tungstate glasses containing Nd 3+ and Er 3+ ions were studied experimentally at 77 and 293 K using spectroscopic methods. The Judd–Ofelt intensity parameters were derived from the absorption spectra and used to calculate the radiative lifetimes and branching ratios. The quantum efficiency η = 0.95 of the 4F 3/2 level of Nd 3+ ion is higher than the typical value of other tellurite-based glasses. For low concentration of Er 3+ ions, the luminescence decay of the 4S 3/2 and 4I 11/2 levels is governed by radiative transitions and multiphonon relaxation involving the Te-O highest energy vibrations. 相似文献
2.
Phase relations in the Na 2O–Al 2O 3–Nb 2O 5and CaO–Al 2O 3–Nb 2O 5systems were studied. The Na 2O system was found to contain neither ternary compounds nor niobate–aluminate solid solutions. In the CaO system, a ternary compound of composition 4CaO · Al 2O 3·Nb 2O 5was identified (cubic structure, a= 7.628 Å, Z= 2, meas= x= 4.43 g/cm 3). 相似文献
3.
Some ternary Gd 2O 3–Bi 2O 3–B 2O 3 glasses are prepared, and crystallization behavior and second harmonic intensity are examined to develop new non-linear optical crystallized glasses. The glasses with Gd 2O 3 contents of 8–14 mol% have large densities of over 6 g/cm 3 and large refractive indices of ~ 1.9. Transparent surface crystallized glasses consisting of two kinds of crystalline phases with different morphologies, i.e. plate shape and needle shape crystals, are fabricated by heat-treatment at temperatures between glass transition and crystallization temperatures. From second harmonic generation microscope observations, micro-Raman scattering spectra and XRD analyses, plate shape crystals are determined to be non-linear optical Gd xBi 1KxBO 3 and needle shape crystals are Bi 3B 5O 12 having no second-order optical non-linearity. Since crystallized glasses consisting of Gd xBi 1KxBO 3 crystals exhibit relatively strong SHGs, they have a high potential for application to light control devices. 相似文献
4.
Some ternary Gd 2O 3–Bi 2O 3–B 2O 3 glasses are prepared, and crystallization behavior and second harmonic intensity are examined to develop new non-linear optical crystallized glasses. The glasses with Gd 2O 3 contents of 8–14 mol% have large densities of over 6 g/cm 3 and large refractive indices of ∼1.9. Transparent surface crystallized glasses consisting of two kinds of crystalline phases with different morphologies, i.e. plate shape and needle shape crystals, are fabricated by heat-treatment at temperatures between glass transition and crystallization temperatures. From second harmonic generation microscope observations, micro-Raman scattering spectra and XRD analyses, plate shape crystals are determined to be non-linear optical Gd xBi 1−xBO 3 and needle shape crystals are Bi 3B 5O 12 having no second-order optical non-linearity. Since crystallized glasses consisting of Gd xBi 1−xBO 3 crystals exhibit relatively strong SHGs, they have a high potential for application to light control devices. 相似文献
5.
In this paper, SiO 2–Au–Cu 2O core/shell/shell nanoparticles were synthesized by reducing gold chloride on 3-amino-propyl-triethoxysilane molecules attached silica nanoparticle cores for several stages. Cu 2O nanoparticles were synthesized readily with the size of 4–5 nm using a simple route of sol–gel method Then, they were clung to the surface of Au seeds. The morphology of the resultant particles was studied using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Transmission electron microscopy images demonstrate growth of monodispersed gold seeds and Cu 2O nanoparticles in narrow size up to 10 nm and 5 nm, respectively. The presence of gold and Cu 2O coating was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy and UV–Vis spectroscopy. Absorption spectroscopy shows considerably 40 nm blue shift in absorption edge for SiO 2–Au–Cu 2O nanostructure rather than SiO 2–Au core/shell nanoparticles. 相似文献
6.
Electron paramagnetic resonance (EPR) and magnetic susceptibility measurements have been performed on xCr2O3(1–x)[Bi2O3·GeO2] glasses with 0相似文献
7.
Phase relations in the systems Al 2TiO 5–Fe 2O 3, Al 2TiO 5–Cr 2O 3, and Al 2O 3–TiO 2–Fe 2O 3 are investigated, and the composition ranges of pseudobrookite Al 2
– 2x
M 2x
TiO 5 (M = Fe, Cr) solid solutions are determined. 相似文献
8.
The phase region of cubic perovskite-like solid solutions ( a = 8.28–8.40 Å) in the Y 2O 3–BaO–WO 3–CuO system is outlined, and the phase compatibility diagram of the BaWO 4–BaCuO 2–Y 2Cu 2O 5–1010 (1010 = Y 2WO 6 + Y 2W 3O 12) is constructed. 相似文献
10.
Bioactivity and magnetic properties were investigated in glass and glass ceramics based on the SiO 2–Na 2O–Fe 2O 3–CaO–P 2O 5–B 2O 3 system to find their suitability as thermoseed for hyperthermia treatment of cancer. The effect of change in compositions on bioactivity was examined in simulated body fluids. The glass ceramic samples exhibit Na 3CaSi 3O 8 and Na 3-XFe XPO 4 phases. After dipping the glass ceramic samples in simulated body fluids silica hydrogel first forms, followed by an amorphous calcium phosphate layer. Magnetic and microwave resonance experiments further demonstrate the potential of these glass ceramics for possible use in hyperthermia. 相似文献
11.
Journal of Materials Science: Materials in Electronics - 1Eu2O3–3BaO–20Nb2O5–76TeO2 glass and the corresponding glass-ceramics were synthesized with the aim to investigate the... 相似文献
12.
Ac conductivity measurements and its analysis has been performed on xBi 2O 3–(65? x)Li 2O–20ZnO–15B 2O 3 (0 ≤ x ≤ 20) glasses in the temperature range 30–300 °C and a frequency range of 100 Hz to 1 MHz. The dc conductivity increased and the activation energy decreased with lithium content. The frequency dependent conductivity has been analyzed employing conductivity and modulus formalisms. The onset of conductivity relaxation shifts towards higher frequencies with temperature. The Almond–West conductivity formalism is used to explain the scaling behavior, and the relaxation mechanism is independent of temperature. 相似文献
13.
Erbium doped β-Ga(2)O(3) nanowires and microwires have been obtained by a vapour-solid process from an initial mixture of Ga(2)O(3) and Er(2)O(3) powders. X-ray diffraction (XRD) analysis reveals the presence of erbium gallium garnet as well as β-Ga(2)O(3) phases in the microwires. Scanning electron microscopy (SEM) images show that the larger microwires have a nearly rectangular cross-section. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) analysis show good crystal quality of the β-Ga(2)O(3) nanowires. The nanostructures have been studied by means of the cathodoluminescence technique in the scanning electron microscope. Er intraionic blue, green and red emission lines are observed in luminescence spectra even at room temperature, which confirms the optical activity of the rare earth ions in?the grown structures. Mapping of the main 555?nm emission intensity shows a non-homogeneous distribution of Er ions in the microstructures. 相似文献
14.
Quaternary tellurite glass systems (70 ? x)TeO 2–20WO 3–10Li 2O– xLn 2O 3 where x = 0, 1, 3 and 5 mol% and Ln are La, Pr, Nd, Sm, Er and Yb, respectively, have been prepared by the melt quenching technique. Densities of the obtained glasses were measured and the molar volume was calculated. IR absorption spectra of the present glass systems were determined at room temperature over the range of wavenumbers from 400–1,600 cm ?1. Raman spectra of the present glass samples were measured in the range of 30–1,030 cm ?1. Density, molar volume, IR and Raman spectra of the glasses were discussed by calculating average cross-link density, packing density, theoretically calculated Poisson’s ratio and number of bonds per unit volume of the studied glasses. Also, the quantitative interpretations were based on concentration of ions per unit volume of Te, Ln and O, short distance in nanometre between ions for (Te–O) of TeO 4 and TeO 3 groups, (W–O) of WO 4, WO 6 groups and calculated wavenumber, $ \bar{\upsilon } $ , for TeO 4 and TeO 3, respectively. The average stretching force constant that present in these quaternary glasses has been calculated in order to interpret the data obtained. 相似文献
15.
Cu 2O·TeO 2 and CuI·Cu 2O·TeO 2 glasses were synthesized and characterized by complex impedance measurement, Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy techniques. Samples of the binary and the ternary systems are found to have both Cu + and Cu 2+ with their relative concentration being composition dependent. Bonds like -O-Cu 2+-O-, leading to the formation of bridging oxygen are found to form in the binary system. Structural units like (Te 3O 8
4–) n are also found to form when Cu 2O content is high in the binary system. Phase separation is observed in the ternary system. The glass structure and hence the ionic conduction behavior are found to depend upon chemical composition. When CuI content exceeds 60 mol%, the crystalline phase of -Cul gets stabilized at room temperature, thus causing the enhancement in conductivity. 相似文献
16.
Heavy metal oxide B 2O 3–PbO–Bi 2O 3–GeO 2 transparent glass doped with Sm 3+ was synthesized and implanted with Au + using energy of 300 keV and fluence of 1 × 10 16 cm −2. The annealing of the implanted glass at moderate temperature below the glass transition temperature induced the nucleation of gold nanoparticles, confirmed by the characteristic absorption band in the visible range and by transmission electron microscopy. Using Miés and Doylés theories for the surface plasmon resonance, the average size of the gold nanoparticles was about 4.6 nm, similar to the values observed by transmission electron microscopy. It was also observed the crystallization of a thin layer of the glass at the implanted surface after annealing, detected by X-ray diffraction and scanning electron microscope. Visible and near-infrared emission of Sm 3+ was enhanced after annealing of the glass implanted with gold. Judd–Ofelt parameters and radiative parameters were calculated for the glass doped with Sm 3+ with and without gold nanoparticles. 相似文献
17.
Ternary Sb2O3–B2O3–K2O glass system, with general composition of x Sb2O3–(70-x) B2O3–30 K2O (where x?=?0, 10, 20, 30, 40, 50) were prepared using melt-quenching technique. Structures of these glasses were investigated using XRD analysis and FT-IR spectroscopy. The optical properties were investigated using the UV–Vis NIR JASCO (Model V-670) Double Beam Spectrophotometer. Different physical parameters, such as density (ρ), molar volume (VM), oxygen molar volume (VO) and oxygen packing density values (OPD) have been estimated. Also, the Gamma radiation shielding ability have been characterized for the investigated glasses using Phy-X/PSD software in the photon energy range (0.015–15 MeV). XRD analysis confirm the amorphous nature of the prepared glasses. The optical energy gap of SBK glasses is decreasing from 4 to 2.63 eV with increasing Sb2O3 content while refractive index is increasing from 2.17 to 2.5 because of increasing the non-bridging oxygens (NBOs) in the glass matrix. The molar refractivity (Rm), molar polarizability (αm) and the third-order nonlinear optical susceptibility values χ3 have been calculated, their values are found to increase with increasing Sb2O3 content. Glass density and molar volume values for the SBK glasses increase with increasing Sb2O3 content. Increasing the Sb2O3 concentration enhance the radiation shielding features of the prepared glasses against gamma rays and neutrons. Hence, the mass attenuation coefficient (MAC) increases from 8.6 to 35.4 cm2/gm while the half value layer (HVL) decreases from 0.036 to 0.0046 cm at 0.015 MeV as the Sb2O3 concentration increases from 0 to 50 mol%. The fast neutron cross section of the six investigated SBK glasses are (0.087, 0.092, 0.095, 0.091, 0.094 and 0.092 cm?1), respectively. 相似文献
18.
We have investigated the effect of the deposition of an HfO 2 thin film as a gate insulator with different O 2/(Ar + O 2) gas ratios using RF magnetron sputtering. The HfO 2 thin film affected the device performance of amorphous indium–gallium–zinc oxide transistors. The performance of the fabricated transistors improved monotonously with increasing O 2/(Ar + O 2) gas ratio: at a ratio of 0.35, the field effect mobility of the amorphous InGaZnO thin film transistors was improved to 7.54 cm 2/(V s). Compared to those prepared with an O 2/(Ar + O 2) gas ratio of 0.05, the field effect mobility of the amorphous InGaZnO thin film transistors was increased to 1.64 cm 2/(V s) at a ratio of 0.35. This enhancement in the field effect mobility was attributed to the reduction of the root mean square roughness of the gate insulator layer, which might result from the trap states and surface scattering of the gate insulator layer at the lower O 2/(Ar + O 2) gas ratio. 相似文献
19.
This paper reports on the effect of the chemical composition on the glass structure, the coefficients of thermal expansion and the fluorescence properties of Sm 3+-doped La 2O 3–Al 2O 3–SiO 2-glasses. The silica concentration was varied between 50 and 70 mol% and the La 2O 3:Al 2O 3 ratio between 50:50 and 30:70. The glass formation and the densities are evaluated and FTIR reflectance spectra, coefficients of thermal expansion and fluorescence lifetimes are determined. It is shown that high SiO 2 concentrations and low La 2O 3:Al 2O 3 ratios result in relatively high fluorescence lifetime (2.19 ms, 4G 5/2) and low coefficients of thermal expansion (4.6 × 10 ?6/K). The coefficients of thermal expansion and the fluorescence lifetimes show a linear dependency on the ratio LaO 3/2/(AlO 3/2 + SiO 2). 相似文献
20.
The K 2O–B 2O 3– SiO2, K 2O–B 2O 3– SiO2–2 %Al 2O 3, K 2O–B 2O 3– SiO2–4 %Al 2O 3 glasses with different Al 2O 3 content were prepared. Different proportions (50, 55, 60, 65, 70 %) of the three glasses were respectively mixed with alumina ceramic-filler, then the mechanical and dielectric properties were investigated. The results showed K 2O–B 2O 3– SiO2–2 %Al 2O 3 glass/alumina filler (glass:alumina = 60:40) had the excellent comprehensive properties, so further study was continued with part of alumina ceramic-filler replaced by the silica ceramic-filler on this composite. Then the X-ray diffraction analysis revealed that the alumina and silica fillers existed as the crystal phase, and the densification was seriously damaged when the silica content reached to three quarters of the fillers. With the increase of the silica-filler, the composites’ density and dielectric constant exhibited uniform decrease, but thermal expansion coefficient (TEC) uniformly increased. When the glass:alumina:silica was equal to 60:30:10, a best composite property was presented as a bulk density of 2.582 (g cm ?1), a dielectric constant of 6.1 and a dielectric loss of 2 × 10 ?3 at 1 MHz, a flexural strength of 168 MPa, and a TEC of 8.62 × 10 ?6 °C ?1. 相似文献
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