The compressive strength of portland cement-based material is closely linked with its microstructure. Scanning electron microscopy (SEM) with backscattered electrons (BSE) and x-ray microcomputed tomography (mu CT) are capable of visualizing the microstructure. Processing microstructural images using techniques such as threshold segmentation relies heavily on expert knowledge and is prone to bias. This study uniquely employs convolutional neural networks to comparatively analyze the correlation between compressive strength and microstructural images obtained from mu CT and BSE. The proposed method can automatically extract features from the images. The findings indicate that BSE images exhibit a stronger correlation with compressive strength than 2D mu CT images. Under water-to-cement ratios of 0.25 or 0.7, the correlation between 2D mu CT images and compressive strength decreases with increasing curing age. Additionally, the 3D spatial information in 3D mu CT images is also correlated with compressive strength, while its correlation is lower than that of SEM-BSE images. This comparative study highlights the advantages and limitations of SEM-BSE and mu CT in microstructural analysis of portland cement-based materials, offering new insights into understanding compressive strength through deep learning techniques.
High-density glass has emerged as a viable alternative for next-generation scintillation applications owing to its exceptional physical and chemical stability, in addition to its cost-effectiveness. A series of Ce3+-activated gadolinium gallium borosilicate (GGBSx) glass scintillators was synthesized via vacuum melt-quenching. With the Gd2O3 content increases, both the density (5.86 to 6.05 g/cm3) and molar volume (36.43 to 39.79 cm3/mol) exhibit a steady increase. The structural characteristics of the glass system were elucidated through extended X-ray absorption fine structure (EXAFS) analysis. GGBS1 glass exclusively includes Ce3+, which adopts a hexahedral [CeO6] configuration, whereas Gd exhibits both hexahedral and octahedral coordination configurations, characterized by a bond length of 2.35±0.1 Å and a σ2 of 0.0122±0.0015 Å2. In addition, as the Gd2O3 content grows, the shallow trap depth escalates from 0.804 to 0.858 eV, whereas the deep trap depth initially ascends from 0.948 to 1.434 eV before subsequently declining to 1.010 eV. The GGBS1 glass exhibits a high transmittance of around 80
Tb3+-doped gadolinium borosilicate glass scintillators with varying Gd2O3 concentrations were prepared by the conventional melt-quenching technique. The influence of Gd2O3 concentration on the density, effective atomic number, X-ray excited luminescence (XEL) intensity, and Gd3+ -> Tb3+ energy transfer efficiency of the glass scintillators was systematically investigated. As the Gd2O3 concentration increased from 0 mol% to 30 mol%, the transmittance of the glass scintillators remained at approximately 85 %, the density increased from 5.29 g/cm(3) to 6.01 g/cm(3), the effective atomic number (Z(eff)) increased from 46.1 to 56.2, and the photoluminescence quantum yield increased from 71.4 % to 81.9 %. Furthermore, the energy transfer efficiency between Gd3+ and Tb3+ increased from 74.6 % to 91.8 %. Compared with the previous sample, the integrated XEL intensity increased by 69 %. The integrated XEL intensity of the optimal glass reached approximately 223 % of Bi4Ge3O12, and a spatial resolution of 20 lp/mm was achieved. Additionally, the integral intensity of photoluminescence at 500 K is 92 % of its initial value. Therefore, the Tb3+-doped gadolinium borosilicate glass scintillator holds immense potential for high-resolution X-ray imaging.
Elucidating the composition-structure-property relationships in La2O3-B2O3-CaO (LBC) glasses is crucial for optimizing the dielectric properties of LBC glass/Al2O3 composites. This study investigates the effect of P2O5 content on the crystallization behavior and dielectric properties of LBC glasses. The low-polymerization borate network renders a high crystallization tendency to the glass. P2O5 existed primarily as PO43- and P & Oslash;O32- units (& Oslash;: bridging oxygen) in the glass. With an increase in the P2O5 content, the crystallization tendency of LBC glass initially decreased and subsequently increased. Concurrently, LaBO3 was progressively replaced by LaPO4 in the sintered glass-ceramic; this was accompanied by an increase in porosity. Calculations based on the P-V-L theory revealed that CaB2O4 and LaPO4 exhibit a low dielectric constants and high lattice energy, which contribute to reducing both the dielectric constant and dielectric loss of the sintered glass-ceramics. Under the combined influence of the varying crystal phase content and porosity, the dielectric constant of the sintered glass-ceramics gradually decreased with an increase in the P2O5 content, whereas the dielectric loss initially increased and subsequently decreased.
Integrating functional perovskites on an amorphous microchannel plate (MCP) glass faces challenges regarding the lack of ordered nucleation sites and stringent thermal budgets. Herein, we propose a surface energetics-based atomic layer deposition (ALD) strategy to achieve template-assisted oriented BaTiO3 growth via a (101)-oriented anatase TiO2 seed layer. Systematic investigation of the TiCl4/O3 process reveals a kinetic-to-thermodynamic transition at 300 °C, triggering a singular (101) preferred orientation. Combined DFT calculations and Wulff construction elucidate that this texture evolution is governed by a thermally activated surface energy minimization mechanism, driven by the intrinsic stability of the (101) facet. Crucially, the optimized seed layer acts as a multifunctional template: it not only transforms BaTiO3 growth from random polycrystalline morphology to a singular (100) orientation with suppressed bulk carbonate impurities but also ensures excellent conformality and uniformity throughout the high aspect ratio microchannels. This study clarifies the thermodynamic mechanism of oriented growth on amorphous substrates, providing a versatile surface engineering pathway for constructing high-performance MCP-based heterojunction devices.
