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51.
《Ceramics International》2022,48(17):24310-24318
We study the impact of yttrium oxide (Y2O3) on the optical properties of iron-doped borate glasses. A series of borate glasses, with a diluted and constant amount of Fe2O3, doped with various amounts of Y2O3 (labeled as BNaFeY-glasses) was prepared and studied. The impact of Y2O3 doping on the optical transitions of BNaFeY-glasses was studied by analyzing the optical absorption spectra. The presence of Fe cations, with their Fe3+ state, leads to the appearance of absorption in the ultraviolet region. Furthermore, the optical transmittance spectra proved the transparency of all BNaFeY-glasses. Moreover, the transmittance of the sample with the highest Y2O3 content is about 93 % within the visible range. Because of the diluted Fe content within BNaFeY-glasses, the five absorption bands of Fe are not observed. So, these bands are detected by magnifying the spectra within the visible region. These bands are labeled ?1, ?2, ?3, ?4 and ?5 at wavelengths 454.5, 518.4, 652.5, 707 and 808 nm respectively. These bands were used to calculate the crystal field splitting (10Dq) for all BNaFeY-glasses. The outstanding 10Dq increment with further Y2O3 doping was explained in terms of more interactions between Fe cations and their surroundings. On the other side, the shielding parameters were considered to examine the competence of these transparent glasses against nuclear radiation. We found that the sample doped with the highest amount of Y2O3 has the highest linear attenuation coefficient and the lowest half-value layer (HVL). From the HVL results, we need a thickness of 3.646 cm from the sample with 5 mol% of Y2O3 to get protection from 50% of the photons with energy of 0.662 MeV, and this thickness is increased to 5.137 cm when the energy is 1.333 MeV. 相似文献
52.
Ekaterina Koroleva Ilya Reshetov Ekaterina Babich Sergey Vakhrushev Dmitry Tagantsev Andrey Lipovskii 《Journal of the American Ceramic Society》2022,105(5):3418-3427
Broadband dielectric spectroscopy (BDS) was applied to study polarization phenomena in alkaline silicate glasses, in particular, properties and structure of subsurface (anodic) polarized layers forming in poling with deposited film electrodes of different structures. A model of poled glasses which does not contradict experimental data is proposed. In accordance with the model, a poled glass is presented as two resistor-capacitor circuits in a series connection, one of which is the polarized layer and another is the rest of the sample. It is found that the electric properties of the layers essentially depend on the structure of the anodic electrode used in glass poling. It is also shown that the dielectric response of poled glass samples is mainly determined by the electric properties of the submicron polarized layers and this gives an opportunity to reveal specific properties of the layers rather than ones of the glass sample bulk. Revealed temperature dependence of DC conductivity of the polarized layers obeys Arrhenius's law, and determining activation energy does not depend on the electrode. Finally, it is noted that today above-mentioned information about polarized layers can be obtained only by BDS. 相似文献
53.
Ho Kim Dan Nguyen Minh Ty Dacheng Zhou Jianbei Qiu Anh-Luan Phan 《Journal of the American Ceramic Society》2020,103(11):6356-6368
In this paper, we study the influence of Cr3+ on yellowish-green upconversion (UC) emission and the energy transfer (ET) of Er3+/Cr3+/Yb3+ tri-doped in SiO2–ZnO–Na2O–La2O3 (SZNL) zinc silicate glasses under excitation of the 980 nm laser diode (LD). The influence of Cr3+ on enhancing the red UC emission of Er3+/Cr3+/Yb3+ tri-doped in SiO2–ZnO–Na2O–La2O3 zinc silicate glasses under the excitation of 980nm LD was also investigated. The ET processes between Yb3+, Cr3+, and Er3+, together with the combination of Yb3+-Cr3+-Er3+, which led to the green UC emission intensity of Er3+/Cr3+/Yb3+ tri-doped in SiO2–ZnO–Na2O–La2O3 zinc silicate glasses bands centered at ~546 nm have been significantly enhanced. By increasing the concentration of Cr3+ from 0 up to 5 mol.%, we can locate the Commission Internationale de l'éclairage (CIE) 1931 (x; y) chromaticity coordinates for UC emissions of Er3+/Cr3+/Yb3+ tri-doped in the central position of the yellowish-green color region of CIE 1931 chromaticity diagram. Besides, the ET processes between the Yb3+, Cr3+, and Er3+ are also proposed and discussed. 相似文献
54.
The EPR, optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Ce-doped glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 compositions have been investigated and analysed. The borate glasses were obtained from the corresponding polycrystalline compounds in the air atmosphere, using standard glass technology. The EPR signals of the isolated Ce3+ and pair Ce3+–Ce3+ centres, coupled by magnetic dipolar and exchange interactions were registered at liquid helium temperatures. The characteristic for glass host broad bands corresponding to the 4f → 5d transitions of the Ce3+centres have been observed in the optical absorption and photoluminescence (emission and excitation) spectra. The obtained luminescence decay curves can be satisfactory described by exponential function with lifetimes in the 19.8–26.1 ns range, which depend on the basic glass composition. The local structure of Ce3+ centres in the investigated glasses has been considered and discussed. 相似文献
55.
56.
《Intermetallics》2014
Effects of Cu addition on the glass-forming ability (GFA), thermal stability, magnetic properties and crystallization process of (Fe0.76Si0.09B0.1P0.05)99−xNb1Cux (x = 0, 0.25, 0.5, 0.75, 1) alloys were investigated. The introduction of Cu effectively stimulates the precipitation of the α-Fe(Si) without obvious deterioration of the GFA, and successfully modifies the simultaneous precipitation of α-Fe(Si), Fe2B and Fe3(B,P) phases in (Fe0.76Si0.09B0.1P0.05)99Nb1 alloy into separable precipitation of each phase at different temperatures during annealing, leading to the enhancement of soft magnetic properties. The saturation magnetic flux density of the representative (Fe0.76Si0.09B0.1P0.05)98.25Nb1Cu0.75 alloy could be enhanced from 1.43 to 1.51 T after annealing at 530 °C for 10 min due to the precipitation of α-Fe(Si) nanoparticles with a diameter of about 22 nm dispersing randomly in the amorphous matrix. The integration of high GFA and excellent soft magnetic properties makes the FeSiBPNbCu alloys promising soft magnetic materials for industrial applications. 相似文献
57.
Daniela Bortoluzzi Larissa Rodrigues 《Mineral Processing and Extractive Metallurgy Review》2013,34(4):202-209
This article deals with the study of the vitrification mechanism as an inertization method for coal ashes contaminated with heavy metals. Ashes from coal (thermoelectric) and wastes from mining of fluorite and feldspar and from plating were used to compose vitreous systems using a mixture design. The chemical composition of the wastes was determined by XRF and the formulations were melted at 1450°C for 2 h using 10% (mass) of Na2CO3 (as a fluxing agent). The glasses were poured into a mold and annealed (600°C). The characteristic temperatures were determined by thermal analysis (DTA, air, 20°C/min) and the mechanical behavior by HV. As a result, the softening temperature is strongly dependent on silica content of each glass, and the fluorite residue, being composed mainly by silica, strongly affects on the glass transition (Tg) and softening (Ts) temperatures. The hardness by micro-indentation of all glasses is mainly affected by the plating (galvanic) residue due to the high iron and zinc content of this waste. 相似文献
58.
《Optical Materials》2014,36(12):2473-2479
The glass formation and compositional dependences of glass thermal properties and optical properties were investigated in TeO2–ZnO–Na2O–P2O5 system. The refractive index at 1.55 μm and glass transition temperature varied in a wide range from 1.513 to 2.036 and from 265 °C to 376 °C by controlling of the TeO2/P2O5 and ZnO/Na2O content, respectively. These properties enable phospho-tellurite glasses with large freedom in designing and fabrication of hybrid microstructured optical fiber. The structures of glasses were investigated by Raman spectra to understand their dependence of structure on composition. Using the present glasses, some hybrid microstructured optical fibers with various dispersion profiles were designed. 相似文献
59.
The excited state characteristics by means of the excited state absorption (ESA), optical gain and bleaching spectra have been measured for prototype glasses with Li2B4O7 (LBO) and KLiB4O7 (KLBO) compositions activated by Cr3+ ions. The work addressed to search for novel attractive media for broadband lasers and amplifiers, is a completion of detailed spectroscopic evaluation described in earlier papers. One of the examined materials (KLBO), in accordance with optimistic comments given in previous work, reveals a very broad gain spectrum in the near IR, which itself is interesting in view of very few reports on glasses showing optical gain for Cr3+ ions in the low-field local environment. The ESA/gain/bleaching spectra, registered with equipment of improved sensitivity, have been reproduced by calculations, and detailed single configuration coordinate diagram, based on experimental data, has been created for interpretation. 相似文献
60.
Atomistic Origin of the Enhanced Crystallization Speed and n‐Type Conductivity in Bi‐doped Ge‐Sb‐Te Phase‐Change Materials
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Jonathan M. Skelton Anuradha R. Pallipurath Tae‐Hoon Lee Stephen R. Elliott 《Advanced functional materials》2014,24(46):7291-7300
Phase‐change alloys are the functional materials at the heart of an emerging digital‐storage technology. The GeTe‐Sb2Te3 pseudo‐binary systems, in particular the composition Ge2Sb2Te5 (GST), are one of a handful of materials which meet the unique requirements of a stable amorphous phase, rapid amorphous‐to‐crystalline phase transition, and significant contrasts in optical and electrical properties between material states. The properties of GST can be optimized by doping with p‐block elements, of which Bi has interesting effects on the crystallization kinetics and electrical properties. A comprehensive simulational study of Bi‐doped GST is carried out, looking at trends in behavior and properties as a function of dopant concentration. The results reveal how Bi integrates into the host matrix, and provide insight into its enhancement of the crystallization speed. A straightforward explanation is proposed for the reversal of the charge‐carrier sign beyond a critical doping threshold. The effect of Bi on the optical properties of GST is also investigated. The microscopic insight from this study may assist in the future selection of dopants to optimize the phase‐change properties of GST, and also of other PCMs, and the general methods employed in this work should be applicable to the study of related materials, for example, doped chalcogenide glasses. 相似文献