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Scintillation properties of Ce-doped SrF2-Al2O3-B2O3 glasses
摘要： xCeF3-doped (30-x)SrF2-20Al2O3-50B2O3 glasses (x = 0.1, 1.0, 5.0 and 10 mol%) were synthesized by the conventional melt quenching method, and then characterizations for scintillator applications were performed. Regarding the photoluminescence (PL) properties, the glasses show a broad emission band around 360 nm under excitation of approximately 325 nm, and the decay time constant is several tens of nano-seconds. From the results, the origin is attributed to the 5d → 4f transitions of Ce3+. As scintillation properties, the X-ray induced scintillation spectra and decay time constants are reasonably consistent with the PL. Among the present glass samples, the scintillation intensity is the highest when doped with 1% Ce. The light yields of the 1% Ce-doped glass shows 240 photons/MeV under 57Co 122 keV γ-ray exposure. The light yields were derived as relative values to that of commercial GS20 glass scintillator. This is the ?rst report on the scintillation light yields of Ce-doped SrF2-Al2O3-B2O3 glasses. Furthermore, the materials also exhibit thermally stimulated luminescence (TSL) properties with a major glow peak around 80 °C, and the sensitivity to radiation dose is as low as 0.1 mGy for the 0.1% and 1.0% Ce-doped glasses with a good linearity con?rmed to 100 mGy.
关键词： Photoluminescence,Oxy?uoride glasses,TSL,Scintillation,Aluminoborate glasses
更新于2025-09-10 09:29:36
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Glasses in the NaPO3-WO3-NaF ternary system: preparation, physical properties and structural studies
摘要： Oxyfluoride glasses with composition x WO3 - 30 NaPO3 - (70-x) NaF, with 30 ≤ x ≤ 70 were prepared by melt-quenching and characterized with respect to their bulk physical properties and ionic conductivities. As the NaF content increases, the glass transition temperature, Tg, decreases systematically. Impedance measurements reveal no clear effect of NaF content upon room temperature electrical conductivities and activation energies. There is, however, a significant decrease of the Arrhenius pre-exponential factor with increasing WO3 content, suggesting that the electrical conductivities measured in this glass series are increasingly influenced by an electronic contribution. This contribution may be related to a W5+ → W6+ electron hopping process detected in the optical absorption spectra. Detailed spectroscopic investigations by Raman scattering and multinuclear one- and two-dimensional solid-state NMR experiments indicate that NaF acts like a network modifier resulting in the formation of W-F bonds via breakage of W-O-W and W-O-P linkages, with the former process being the preferred one. The concomitant decrease in network connectivity caused by these processes accounts for the experimentally observed decrease in glass transition temperatures with increasing NaF contents.
关键词： Tungsten glasses,Glass structure,Ionic conductivity,Phosphate glasses,Mixed conductivity
更新于2025-09-10 09:29:36
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Investigation of thermal and electrical properties of As–Se glasses modified with Cu using DSC and AC impedance spectroscopy
摘要： Investigations of thermal properties of CuxAs50Se50 ? x chalcogenides were carried out using a differential scanning calorimeter. It was established that copper introduction significantly affects the complexity of structural network. This was indicated by double-stage crystallization process in the compound Cu15As50Se35. Besides α relaxation, all the glasses during heating show β relaxation. The complexity of the network influences the conductivity values and transport properties in a way of higher DC and AC conductivity for the compound with the highest Cu share. Impedance spectra show two semicircles, indicating the existence of two polarization processes in different frequency ranges. The presence of kinetic and as well as diffusion processes in polarization of the samples with x = 10 and 15 at% of Cu strongly affects the unusually high values of the real part of dielectric permittivity in low- and medium-frequency range.
关键词： AC impedance spectroscopy,electrical properties,thermal properties,Cu modification,DSC,As–Se glasses
更新于2025-09-10 09:29:36
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Field Expansion for Acquired Monocular Vision Using a Multiplexing Prism
摘要： SIGNIFICANCE: Acquired monocular vision (AMV) is a common visual field loss. Patients report mobility difficulties in walking due to collisions with objects or other pedestrians on the blind side. PURPOSE: The visual field of people with AMV extends more than 90° temporally on the side of the seeing eye but is restricted to approximately 55° nasally. We developed a novel field expansion device using a multiplexing prism (MxP) that superimposes the see-through and shifted views for true field expansion without apical scotoma. We present various designs of the device that enable customized fitting and improved cosmetics. METHODS: A partial MxP segment is attached (base-in) near the nose bridge. To avoid total internal reflection due to the high angle of incidence at nasal field end (55°), we fit the MxP with serrations facing the eye and tilt the prism base toward the nose. We calculated the width of the MxP (the apex location) needed to prevent apical scotoma and monocular diplopia. We also consider the effect of spectacle prescriptions on these settings. The results are verified perimetrically. RESULTS: We documented the effectivity of various prototype glasses designs with perimetric measurements. With the prototypes, all patients with AMV had field-of-view expansions up to 90° nasally without any loss of seeing field. CONCLUSIONS: The novel and properly mounted MxP in glasses has the potential for meaningful field-of-view expansion up to the size of normal binocular vision in cosmetically acceptable form.
关键词： prism glasses,visual field loss,field expansion,multiplexing prism,Acquired monocular vision
更新于2025-09-10 09:29:36
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The influence of niobium on the structure of Nb2O5–ZnO–P2O5 glasses
摘要： Bulk glasses of the compositional series (A) xNb2O5–(50-x)ZnO–50P2O5 and (B) xNb2O5–50ZnO-(50-x)P2O5 were prepared to investigate possible substitution of cation (Zn2+), series A, and anion (PO3?), series B, with niobium and the effect of this substitution on the structure, density, molar volume, glass transition temperature and coefficient of thermal expansion. The structure was studied by Raman and 31P MAS NMR spectroscopies. The chemical model, based on the idea of chemical compounds as components with the lowest Gibbs energy and therefore the most stable, and on the results of 31P MAS NMR spectroscopy, was proposed for series B. It was found that niobium acts in glasses of series B only as a cation NbO3+, unlike the original idea of forming an anion of NbO?, that is, similarly to series A, where it replaces the cation. This leads to a change in the metaphosphate network of series B to the network that is similar to series A glass. The validity of this idea was verified by experimentally obtained compositional dependencies of molar volume, glass transition temperature and thermal expansion coefficient. Changes observed in thermal measurements indicate the evolution of a more rigid structure and more intensive cross-linking of the phosphate chains with increasing content of niobium.
关键词： Phosphate glasses,Chemical model,Structure,Niobium,Thermal properties
更新于2025-09-10 09:29:36
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Structural and Luminescent property of Holmium doped Borate Glasses
摘要： Holmium doped Lithium Lead Borate glasses of different compositions were prepared by melt quenching technique. Fourier transform infrared investigations on lithium lead borate glasses have been made to study the local order and vibrations of atoms in the glass network and it contains mainly BO3 and BO4 structural units. Photoluminescence techniques were employed to investigate the luminescent property of these glasses excited at 451nm. Blue emission have been observed from the transition 495 ( 5F3 —? 5I8 ).
关键词： Photoluminescence,Luminescent property,FTIR,Holmium doped Borate Glasses
更新于2025-09-10 09:29:36
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Optical properties and gamma-shielding features of bismuth borate glasses
摘要： In the present work, six bismuth borate glass samples with chemical formula (75?x)B2O3–xBi2O3–10CaO–10Na2O–5Al2O3, (x = 0.0–25.0 mol%) have been manufactured. UV–visible spectral distributions for the investigated system were measured in the range of 250–850 nm. The optical absorption data showed the existence of allowed indirect transitions. The optical energy gap values ( Eopt. g ) via Tauc’s model vary from 3.39 to 2.45 eV. The complex dielectric constant ( ??? ) was evaluated. All the optical parameters are found to be sensitive to the concentration of Bi2O3. Also, gamma photons’ attenuation features such as the mass attenuation coefficient (μ/ρ), gamma photon transmission function (I/Io), effective atomic number (Zeff), and half value thickness (HVT) for the investigated glass samples were estimated using MCNPX code and XCOM program in the range of 0.356–1.33 MeV. Replacement of B2O3 by Bi2O3 enhances the ability of glass samples to attenuate gamma photons. The results revealed that the studied glasses can be considered as candidate for optical fiber, devices, and gamma shieling.
关键词： XCOM program,Bismuth borate glasses,MCNPX code,Gamma-shielding,Optical properties
更新于2025-09-10 09:29:36
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Study of the optical properties of amorphous As–Se–S thin films
摘要： This study investigates the effects of substitution of selenium by sulfur on the optical constants of amorphous (a-)As20Se80 ? xSx films (x = 0, 4, 8, 12, 16, and 20 at%), where the coordination number for both Se and S is the same. The absorption coefficient, α, and the index of refraction, n, were derived using the transmission spectra in a wide range of wavelengths from 400 to 2500 nm. This revealed that the index of refraction for the a-As20Se80 ? xSx system decreases with increase in sulfur content throughout the range under study. The effective coordination number of As has been determined based on the refractive index dispersion analysis. A decreasing in Nc from 4.022 to 3.752 with increase content of sulfur from 0 to 20 at% has been recorded. In addition, the optical bandgap, Eg, of the a-As20Se80 ? xSx thin films increases with increase in S content which can be explicated in terms of the chemical bond approach.
关键词： optical bandgap,refractive index,amorphous As–Se–S thin films,chalcogenide glasses,optical properties
更新于2025-09-10 09:29:36
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Study of dielectric relaxation and thermally activated a.c. conduction in multicomponent Ge10-xSe60Te30Inx (0 ≤ x ≤ 6) chalcogenide glasses using CBH model
摘要： Amorphous Ge10-xSe60Te30Inx (0 ≤ x ≤ 6) chalcogenide glasses were prepared by melt quench technique. Surface morphology with the chemical composition of the prepared glass was examined using SEM and EDS analysis respectively. Dielectric properties and a.c. conductivity of the multicomponent Ge10-xSe60Te30Inx (0 ≤ x ≤ 6) chalcogenide glasses have been examined in the frequency range 100Hz to 1MHz and temperature range 303 to 328K. It was noticed that dielectric constant and dielectric loss decreases with the increase of frequency and increases with the increase of temperatures. Frequency and temperature dependence of dielectric constant was explained by orientational polarization. The variation of dielectric loss with frequency and temperature was explained by conduction loss and theory of single polaron hopping of charge carriers suggested by Elliot and Shimakawa for chalcogenide glasses. The experimental results show that a.c. conductivity follows the power law where s<1 and value of s decreases with the increase of temperature. The present findings of a.c. conductivity and variation of s with temperatures are reasonably well interpreted in terms of CBH model.
关键词： a c conductivity,dielectric relaxation,Chalcogenide glasses,CBH model,activation energy.
更新于2025-09-10 09:29:36
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Superior fluorescence and high stability of B-Si-Zn glasses based on Mn-doped CsPbBrxI3-x nanocrystals
摘要： CsPbX3 perovskite nanocrystals (NCs) are still limited in their use due to their extreme instability in the air as they will deteriorate in a few days, and their thermal stability is not optimistic. In this study, the red CsPbBrxI3-x (X=1.5, 1.0, 0.8, 0.5, 0.35, 0) NCs and Mn-doped CsPbBrxI3-x NC in zinc borosilicate (B2O3-SiO2-ZnO) glass with cubic perovskite crystal structure were successfully synthesized through melt-quenching and heat-treatment method, which exhibited strong red emission in region of 572 nm ~ 708 nm under 365 nm excitation. Additionally they are stable in the air for several months while showing excellent thermal stability. It is worth mentioning that Mn-doped CsPbBrxI3-x NC glasses are brighter than CsPbBrxI3-x NC glasses under UV light. Because Mn-doped CsPbBrxI3-x NC glasses have good thermal and air stability, they can be used as a red fluorescent material. We fabricated glass with Y3Al5O12:Ce3+ (YAG:Ce3+) phosphor-in-glass (PiG) realized the chromaticity tuning for YAG:Ce3+ phosphor with white light-emitting-diodes (WLED).
关键词： Narrowband emission,Mn2+-Doped CsPbBrxI3-x NC glasses,High stability,High luminescent intensity
更新于2025-09-10 09:29:36