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Subsurface modification induced on ion-exchanged glass substrates by deposition and bombardment
摘要： Ion-exchanged glasses are widely used in optoelectronic devices due to its high strength and optical waveguide effects. The MgF2 films deposited on the ion-exchanged glasses and the ion-exchanged glasses bombarded by argon ions (100 eV) at 220 °C were investigated in the present work. The microstructure of MgF2 films and the structural and physico-chemical properties of the ion-exchanged glasses before and after deposition and bombardment were analyzed by grazing incident X-ray diffraction (GIXRD), field emission scanning electron microscopy (FE-SEM), electron probe micro analysis (EPMA), micro-Raman spectroscopy and surface stress meter. It is shown that MgF2 films exhibit a polycrystalline and microcolumnar structure. The peak of potassium ions concentration distribution in the ion-exchanged glasses, accompanied by outward diffusion of potassium ions, decreases and moves from glass surface to the inner part to different degrees during deposition and bombardment. The potassium ions concentration in the region near the surface of argon ion-bombarded glasses is almost the same as the MgF2-coated glasses. Furthermore, the position and intensity of Raman bands in the subsurface region of the ion-exchanged glasses show obvious changes before and after deposition and bombardment. The values of compressive stress and depth of layer in the MgF2-coated ion-exchanged glasses and the argon ion-bombarded ion-exchanged glasses are far away lower than that of its values obtained in the ion-exchanged glasses. Overall results have shown that variations of chemical composition, Raman bands and surface compressive stress in the exchanged region indicate subsurface modification of the ion-exchanged glasses induced by deposition and bombardment, which provide useful information for the use of the ion-exchanged glasses in further.
关键词： Modification,Ion bombardment,Raman spectroscopy,Ion-exchanged glass,MgF2 thin film
更新于2025-09-23 15:22:29
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Glass transition and crystallization of ZnO-B2O3-SiO2 glass doped with Y2O3
摘要： The effect of Y2O3 on the glass transition kinetics, crystallization kinetics, phase separation and crystallization behavior of 60ZnO–30B2O3–10SiO2 glass has been investigated by non-isothermal differential thermal analysis, scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The glass transition activation energies Eg calculated by using both Kissinger and Moynihan model decrease from 668 kJ/mol to 573 kJ/mol for Kissinger model, and 682 kJ/mol to 587 kJ/mol for Moynihan model with the increase of yttrium oxide doping content from 0 to 6 mol%. And the glass crystallization kinetics parameters, crystallization activation energy Ec and Avrami exponent n stands for crystal growth, are also obtained on the basis of several well developed equations. Increase of about 58 kJ/mol in Ec values obtained by different theoretical equations is caused by addition of 6 mol% yttrium oxide into 60ZnO–30B2O3–10SiO2 glass, and the Avrami exponent (n close to 2) suggests that crystal growth in 60ZnO–30B2O3–10SiO2 glass doped with or without yttrium is mainly one-dimensional growth of crystals. The results on the phase separation and crystallization behavior occurred at 893 K and 993 K respectively for base and doped glass, are well consistent with the glass transition and crystallization kinetics results. Hence, addition of yttrium oxide into 60ZnO–30B2O3–10SiO2 glass decrease the glass transition activation energy while increase the crystallization activation energy of glass, thereby the stability of glass structure is improved. Phase separation phenomenon and crystallization behavior occurred at glass surface provide some useful information for preparing glass ceramics with micro- or nano-crystals in surface.
关键词： Thermal properties,Y2O3,Electron microscopy,Glass
更新于2025-09-23 15:22:29
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Enhanced luminescent properties of Tb3+-doped transparent oxyfluoride glass-ceramics containing YF3 nanocrystals
摘要： Tb3+-doped transparent oxyfluoride glass-ceramics (GC) containing YF3 nanocrystals have been fabricated via a traditional melt-quenching route with appropriate thermal-treatment. The microstructural, luminescent and optical properties of the synthesized material were investigated systematically. The precipitated particles in the glass phase of GC540 are YF3 nanocrystals with a mean size of around 20 nm, which has been confirmed and estimated by XRD and TEM. Compared with the precursor glass (PG), the emission intensity at 545 nm (5D4→7F5) of YF3: Tb3+-doped GC is significantly enhanced (under ultraviolet and X-rays excitation) and the lifetime of GC is longer. It can be confirmed that the preferential enrichment of Tb3+ in the precipitated low-phonon-energy YF3 nanocrystals can effectively reduce non-radiative transitions. The obtained results confirm that such Tb3+-doped YF3 GC might be useful as a novel X-ray scintillating material for slow event detection.
关键词： X-ray excited luminescence spectra,luminescent properties,YF3,Glass-ceramics
更新于2025-09-23 15:22:29
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An investigation on shielding properties of BaO, MoO3 and P2O5 based glasses using MCNPX code
摘要： In the present work, some radiation shielding quantities (mass attenuation coefficients, effective atomic number, effective electron density, half value layer and mean free path) for various BaO–MoO3–P2O5 ternary glass systems have been determined within the 0.015–15 MeV energy range, using WinXCom program. Additionally, the mass attenuation coefficients of all the investigated glasses have been calculated using MCNPX simulation code (version 2.6.0) and compared to those of WinXCom results. Among the studied glasses, BaMoP8 glass sample with MoO3 content of 70% mol is found to have superior gamma-ray shielding characteristics. Moreover, the glasses studied in this paper possess better radiation shielding properties by providing shorter half value layer (HVL) than RS-253 G18 commercial glass and some concrete samples namely ordinary, hematite-serpentine and ilmanite-limonite.
关键词： Attenuation coefficients,MCNPX,MoO3-based glass,WinXCom,Radiation shielding
更新于2025-09-23 15:22:29
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Easy-to-operate fabrication of tapered glass capillaries for microdroplet generations
摘要： Tapered glass capillaries play an important role in micro droplets generation and related micro?uidic applications such as particle synthesis, digital PCR, microrectors. However, its controlled production poses a challenge. Speci?cally, there is di?culty controlling the tip sizes of capillaries with good repeatability at an a?ordable cost, which is critical to producing standard droplets for use by research groups. To produce tapered capillaries, micro needle geometries are ?rst pulled by commercial pipette puller, which yields a sharp tip (i.e. 1-3μm). Those tips need to be enlarged and standardized by post microfabrication. Although larger tips could be achieved by advanced pulling-forging, sanding-forging or breaking-forging methods, the uniformity and repeatability do not meet the requirements for mass production. In this paper, several easy-to-operate fabrication approaches, including mechanical and chemical fabrication methods, are studied. Chemical etching fabrication method shows good repeatability and robust control of dimensions. A capillary droplet micro?uidic device assembled by tapered glass capillaries fabricated by chemical etching method is also presented, which shows good performance for droplet generations. This non-labor intensive fabrication is straightforward and be readily adopted for industrial scale mass production.
关键词： glass capillary,micro fabrication,taper,droplet generation
更新于2025-09-23 15:22:29
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A novel Nd <sup>3+</sup> -doped MgO-Al <sub/>2</sub> O <sub/>3</sub> -SiO <sub/>2</sub> -based transparent glass-ceramics: towards excellent fluorescence properties
摘要： Generally, glass-ceramics have superior properties compared to their parent glasses. Here, we prepared a novel Nd3+-doped MgO-Al2O3-SiO2-based transparent glass-ceramics with excellent fluorescence properties. The effects of Nd2O3 content on the structure and properties of glass-ceramics were studied, aiming to provide a key guidance for preparing this transparent glass-ceramics. The results revealed that the glass stability increased originally and then decreased with increasing Nd2O3 content, so did the variation of wavenumbers in infrared spectra. And these glass-ceramics are mainly composed of cordierite with residual glassy phase. The three phenomenological intensity parameters (Ω2,4,6) and radiative properties were estimated by Judd-Ofelt theory, and the values of Ω2 first decreased and then increased with increasing Nd2O3 content. Three main emission peaks ascribed to the transitions from 4F3/2 to 4I9/2, 4I11/2, 4I13/2 at 898, 1057, 1330 nm were observed, respectively. The branching ratios for 4F3/2→4I11/2 transition increased as the Nd2O3 content raised, and the fluorescence lifetimes of the 4F3/2 level were found to increase first and then decrease with Nd2O3 content (from 181 to 726 μs). The excellent fluorescence properties indicate that this novel glass-ceramics can be used as a potential solid-state optical functional material for 1.06 μm laser emission.
关键词： MgO-Al2O3-SiO2,Judd-Ofelt theory,Nd3+-doped,Transparent glass-ceramics,Solid-state optical functional materials
更新于2025-09-23 15:22:29
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Granular Inhomogeneity Formation during Quartz Glass Melting
摘要： This paper examines the formation of fine-grain inhomogeneity in quartz glass. We demonstrate that this defect emerges during the melting of fine-particle crystalline raw materials and the formation of a three-dimensional intergranular network, which contains a high impurity concentration and has a disordered structure. The present results are inconsistent with the existing believe that incomplete melting of quartz grains is the main cause of the development of fine-grain inhomogeneity. In contrast, prolonged high-temperature heat treatment increases the intergranular impurity concentration and intensifies the effect.
关键词： quartz grit grains,grain boundaries,structural impurities,structure of quartz glass
更新于2025-09-23 15:22:29
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On the Test Method for Determining Residual Stress on the Surface of Tempered Glass
摘要： The residual stress on the surface of tempered glass is very important for its safe service and the quality control. In this study, the sphere indentation and grazing angle surface polarimetry are compared to evaluate the surface residual stress of tempered glass. The test results showed that the measured results are similar, but the data dispersion of the sphere indentation method is little larger. The main reason is stemmed from the different tested area, of which residual stress is a mean value measured by the grazing angle polarization method. Yet for the indentation method, the residual stress in the micro region of glass is more susceptible to the inhomogeneity of material itself. However, it is difficult to select the right multiple optical path difference for the grazing angle polarization method, and it is only applicable when inspecting the tin surface of tempered glass, as well as the tin surface examination instrument. Thus, as a nondestructive testing method, indentation method can be widely used to measure the surface residual stress of glass without being influenced by other factors.
关键词： Indentation method,Surface residual stress,Grazing angle surface polarimetry,Tempered glass
更新于2025-09-23 15:22:29
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Experimental and numerical investigation to rationalize both near-infrared and mid-infrared spontaneous emission in?Pr3+ doped selenide-chalcogenide fiber
摘要： This contribution reports on detailed experimental and numerical investigations of both near-infrared (NIR) and mid-infrared (MIR) photoluminescence obtained in praseodymium trivalent ion doped chalcogenide-selenide glass fiber. The experimental analysis allows for the identification of the radiative transitions within the praseodymium ion energy level structure to account for the photoluminescent behavior. Numerical analysis is carried out using the rate equations' approach to calculate the level populations. The numerical analysis provides further insight into the nature of the radiative transitions in the Pr3+ ion doped chalcogenide-selenide glass and allows for the identification of the electronic transitions, which contribute to the observed photoluminescence. The numerical results agree well with the experimental results.
关键词： chalcogenide glass fibers,optical fiber modelling,lanthanide doped fibers
更新于2025-09-23 15:22:29
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Controlling Fano resonances in multilayer dielectric gratings towards optical bistable devices
摘要： The spectral properties of Fano resonance generated in multilayer dielectric gratings (MDGs) are reported and numerically investigated in this paper. We examine the MDG consisting of numerous identically alternative chalcogenide glass (As2S3) and silica (SiO2) multilayers with several grating widths inscribed through the structure, emphasizing quality (Q) and asymmetric (q) factors. Manipulation of Fano lineshape and its linear characteristics can be achieved by tailoring the layers’ amount and grating widths so that the proposed structure can be applicable for several optical applications. Moreover, we demonstrate the switching/bistability behaviors of the MDG at Fano resonance which provide a significant switching intensity reduction compared to the established Lorentzian resonant structures.
关键词： Fano resonance,silica,optical bistable devices,chalcogenide glass,multilayer dielectric gratings
更新于2025-09-23 15:21:21