Journal of Non-Crystalline Solids: X最新文献

This research examines the influence of surface roughness and the incorporation of ZnO (0.05–0.20 mol%) on the magnesium sulfate: dysprosium oxide: boron oxide (0.1 < x < 0.5) glass ceramic system for dosimeter applications. The parent glasses were prepared using the melt-quenching technique, with all samples melted at 1350 °C, except for B, which was melted at 700 °C. The crystallization, roughness, and optical properties were further determined using X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), and UV–Visible Spectrophotometry, respectively. The glass ceramics were exposed to 2.97 mGy of X-ray radiation ten cycles to assess specific dosimetric capabilities. Among the doped samples, MgSO₄:Dy₂O₃-(0.2B₂O₃:0.05ZnO) exhibited the most promising performance as a dosimeter. Notably, the Thermoluminescence Dosimetry (TLD) readings of the pre- and post-polished 0.2MDB were 1041.96 nC and 1278.84 nC, respectively, with roughness values of 1.83 nm and 54.7 nm. Similarly, the TLD readings of the pre- and post-polished 0.05MDBZ were 1888.33 nC and 3262.63 nC, respectively, with roughness values of 17.3 nm and 19.8 nm. This work highlights that surface roughness significantly enhances trapping efficiency, underscoring the importance of dosimeter polishing as a beneficial step in enhancing their performance.

Understanding the phase transition behavior of phase-change (PC) material with respect to the scaling effect is essential for the application of PC materials. Among all the PC materials, SbTe binary plays a significant role in the well-known Ge-Sb-Te system. Here we have used an unconventional and cost-effective method to fabricate a wide range of prototypical Sb₂Te₃ amorphous nanowires (18–220 nm in diameter) using templated electrodeposition. Compositional, morphological, and structural characterization of the amorphous nanowires were performed, and the crystallization temperature of in-template nanowires was measured using a four-probe resistivity meter. We report that the crystallization temperature of amorphous Sb₂Te₃ nanowires can be tuned with respect to the diameter of the nanowires and a significant increase was observed for the nanowires with diameters ≤35 nm. Our study sheds light on the size-dependent phase transition behavior of PC NWs with implications for further advancement of the PC memory technology.

Phosphate glasses have a range of applications including as hosts for immobilizing radioactive wastes. Studies have shown that addition of iron and/or aluminum oxides can drastically improve the chemical durability of phosphate glasses where the accurate measurement of chemical durability is one of the most important factors for determining the long-term viability of a given waste form. However, due to inconsistencies with the experimental methods used to generate chemical durability data, comparing and interpreting such data is a tedious task. These variables include the temperature of the test, the specimen form (e.g., coupon, particles), the pressure of the test (e.g., atmospheric pressure, elevated pressure in an autoclave), the exposure time, the exposure medium, and how the loss is documented (e.g., total mass lost, normalized elemental release). This review paper summarizes a large collection of chemical durability tests on aluminophosphate glasses in various studies. In addition, the effects of different oxides on the properties of phosphate glasses are summarized.

Nanostructured samples of bioactive glass 60S (BG 60S) with a composition (mol %) of 60% SiO₂, 36% CaO, 4% P₂O₅ were synthesized by the sol-gel method in this research. The bioactivity of the synthesized material was evaluated by in vitro assays. The dynamics of the formation of hydroxyapatite (HA), contributing to the formation of effective bonds with bones and soft tissues during immersion in a simulated body fluid (SBF Kokubo), was evaluated using FTIR, XRD, and SEM-EDX. Changes of the specific surface values, particle size and zeta potential for soaked samples in SBF were also investigated. Determination of the antibacterial activity of BG 60S/vancomycin composites was carried out on test cultures of gram-positive microorganisms being one of the most frequent etiological factors of infectious complications in injuries – Staphylococcus aureus. The effectiveness of the release of the antibiotic was confirmed by determining the zone of inhibition of the test culture using the modified Kirby–Bauer disk diffusion method. It is shown that BG 60S/vancomycin composites are characterized by the preservation of antibacterial properties of vancomycin with its prolonged release, and osteoconductive properties, which are inherent in bioactive sol-gel glass and are promising for practical use in the surgical treatment of bone diseases. Based on the foundings, it is possible to suggest a positive effect of the joint application of BG 60S and vancomycin as part of composites with an effective combination of the functions of bone tissue restoration, treatment and prevention of postoperative infectious complications.

Following the 2011 accident at the Fukushima Daiichi Nuclear Power Plant (1F), contaminated water was treated to remove radionuclides. The water treatment processes generated ∼4500 m³ of secondary wastes including sludges and spent media. Vitrification using GeoMelt® In-Container Vitrification (ICV)™ is a technology being considered for treatment of these wastes. ICV is well suited due to its ability to process a broad range of wastes at high temperatures without the need to pour glass which results in high waste loading and high chemical durability. The objective of this study was to formulate glasses suitable for ICV processing of 1F secondary wastes with high chemical durability. Thirty-six glasses were formulated for different 1F secondary waste blends with loadings ranging from 60 to 92 wt%. Materials Characterization Center durability test number 1 (MCC-1 – ASTM C1220) responses were measured for the glasses in deionized water at 90 °C for 7 to 365 days. Their MCC-1 responses were equal or below those for well-characterized reference waste glasses from US, Japan, and France demonstrating their high durability. The 1F glass MCC-1 data were combined with literature data from US, French, and Japanese high-level waste glasses and a model was fitted to MCC-1 durability response as a function of glass composition. Component effects on MCC-1 responses were discussed in context of glass alteration theory.

The impact of dissolution products on the reaction behaviour of bioactive glasses was explored. Bioactive glass S53P4 particles were immersed in solutions with initial pH of 5–9. After 24 and 72 h, the solution extracts were used for testing unreacted particles. The pH, ion concentrations, and glass surfaces were analysed as functions of immersion time. More Ca, Na, and P dissolved at lower pH (5) than at higher pH (7.4 or 9). The dissolution changed from an incongruent to an apparent congruent with increasing pH. Dissolution products in extracts changed the reaction layer structure on glass particles and led to lower ion release at pH 7.4 and 9. Dissolution increased almost linearly with time in acidic solutions. Silica-rich layer and calcium phosphate were identified on the particles after immersion in all solutions except at pH 9. Local ion concentration variations affected dissolution, leading to nonuniform ion release rates.

In this work, the compositional series of sulfide and mixed oxysulfide (MOS) glasses 0.56Li₂S + 0.44[(0.33-x)PS_5/2 + xPO_5/2 + 0.67SiS₂] was prepared, where 0 ≤ x ≤ 0.33, and their short range order (SRO) structures and their thermal properties have been investigated. Powder x-ray diffraction (XRD) confirmed that the MOS glasses were free from crystallization, with only very minor diffraction peaks in the x = 0 glass being observed. Fourier transform infrared (FT-IR), Raman, and ²⁹Si and ³¹P magic angle spinning (MAS) NMR spectroscopies were used to identify the SRO structures present in these glasses. These spectra revealed oxygen migration from P to Si during synthesis. Although oxygen was introduced in the form of phosphorus oxide, the majority of the oxygen in these glasses ends up being bonded to silicon, thereby creating sulfur-rich SROs centered by phosphorus and MOS SROs centered by silicon. It was further found that the P-S SRO species were predominantly charged non-bridging sulfurs (NBS). The Si SRO species were comprised of neutral bridging oxygens (BOs) and charged non-bridging oxygens (NBOs) and neutral bridging sulfurs (BS) and charged non-bridging sulfurs with the neutral BO and BS species being larger in fraction than the NBO and NBS. These results suggest that the preponderance of the mobile Li⁺ cations in these glasses are located near the more negatively charged P centers and not near the more neutrally charged Si centers. The average negative charge of the P SRO structures was found to be ∼ − 3.0 with ∼97% of the phosphorous species in the P⁰ SRO while the average negative charge of the Si SRO structures was found to be −2.3. Consistent with the creation of the large numbers of NBS on the P and more BOs and BSs on the Si, these values are more negative and more positive, respectively, than the compositionally expected average value of −2.55. Differential scanning calorimetry (DSC) measurements of their glass transition (Tg) and crystallization (Tc) temperatures showed that the Tgs of these glasses are higher than 300 °C and their working ranges, ΔT ≡ Tc – Tg, are ∼100 °C.

The donor-acceptor interaction of a charge-coupled heterostructure encompassing a metal and an amorphous semiconductor subjected to a laser field has many potential applications in the realm of nonlinear optics. In this work, we fabricate an electron donor gold nanoparticle (AuNP) and acceptor amorphous Ge₂₄Se₇₆ heterostructure on a quartz substrate using a sequential thermal evaporation technique. In this charge coupled heterostructure, we demonstrate the ultrafast third-order nonlinear absorptive and refractive response, and their sign reversal compared to pristine Ge₂₄Se₇₆. Enhanced optical nonlinearity in these heterostructures of varying plasmonic wavelengths is due to charge transfer, verified by the Raman spectroscopy. Further, the ultrafast transient absorption measurements support the thesis of charge transfer in the AuNP/Ge₂₄Se₇₆ heterostructure. These findings open up exciting opportunities for developing novel device technologies with far-reaching applications in nonlinear optics.

In this review article, the impact of dissolved water on the viscous properties of soda lime silicate melts is addressed against the background of the upcoming switch from natural gas to hydrogen combustion. This change will lead to an increase in the total water content of the glasses by up to 0.4 mol%. In order to better define possible influences of water speciation, water-rich glasses were synthesised under increasing pressure up to the kbar range. It is shown that a distinction must be made between the influence of dissolved OH-groups and H₂O-molecules in order to accurately reflect the dependence of isokom temperatures on water content. In addition, an increase of one order of magnitude in the tolerance to higher deformation rates was observed for the range of expected increased water contents during isothermal deformation processes, which is based on the time-temperature superposition principle, i.e. congruent flow curves were determined under isokomal conditions.