Search Results (42,667)

This study investigates the structural transformation from the γ-phase into the α-phase in bio-based nylon 5,6 fibers during in situ uniaxial stretching, using X-ray diffraction (XRD) and density functional theory (DFT) calculations. Initially, nylon 5,6 films exhibited a well-defined γ-phase crystalline structure, and the as-spun fibers also retained a γ-phase-dominant structure with partial coexistence of α-phase components. Due to the lattice similarity between the γ- and α-phases, phase separation was challenging in the direction perpendicular to the fiber axis (ab-plane). However, the analysis of the (004) diffraction peaks along the fiber axis (c-axis) enabled the quantitative evaluation of each crystalline component. As the stretching progressed, the α(004) peak intensity gradually increased, indicating a continuous γ-to-α structural transition. Furthermore, DFT calculations revealed that the α-phase has lower energy than the γ-phase, supporting the thermodynamic favorability of the phase transition during elongation. These results provide a comprehensive understanding of the crystalline structure and transformation mechanism in environmentally friendly nylon fibers from both experimental and theoretical perspectives, and offer foundational insights for developing nylon materials with desirable properties through the precise control of crystal phase structures. Full article

We present optical photometry for the afterglow of GRB 201015A, which can be classified as a medium-luminosity gamma-ray burst ($L_{\gamma ,\mathrm{iso}}\approx 2.55\times {10}^{49}\mathrm{erg}{\mathrm{s}}^{-1}$ ) and the associated underlying supernova SN 201015A. A millisecond magnetar engine has been widely suggested to exist in gamma-ray burst (GRB) phenomena. In this paper, we study the effects of the magnetar engine on GRB 201015A/SN 201015A by light curve analysis. We use a smooth broken power-law plus magnetar spin-down model to fit the X-ray and optical light curves of GRB 201015A/SN 201015A. The best-fitting results reveal that the magnetar initial spin period and surface magnetic field at the pole are constrained to be $P_0=16.{80}_{-0.47}^{+0.24}\mathrm{ms}$ and $B_{\mathrm{p}}=0.{80}_{-0.32}^{+0.34}\times {10}^{15}\mathrm{G}$, respectively, and the SN ejected a total mass of $M_{\mathrm{ej}}=2.{55}_{-0.37}^{+1.12}{M}_{\odot }$ and an ejecta velocity of $v_{\mathrm{ej}}=30,{000}_{-2500}^{+4800}\mathrm{km}{\mathrm{s}}^{-1}$, inferring a kinetic energy of $E_{\mathrm{SN}},\mathrm{K}\approx 1.37\times {10}^{52}\mathrm{erg}$. From our analysis, we find that the central engine of GRB 201015A/SN 201015A may well be a magnetar, and the emission from a magnetar central engine can be solely responsible for powering SN 201015A. Full article

In this study, we present a novel and straightforward approach for the synthesis of copolymers and nanocomposites based on α- and β-pinene, employing an eco-friendly and cost-effective nano-reinforcing filler. The copolymers (α-co-β-P) were produced through cationic copolymerization, using AlCl₃ as a catalyst. The structural characterization of the resulting copolymer was validated through FT-IR, ¹H-NMR spectroscopy, and differential scanning calorimetry (DSC). The molecular weight of the obtained polymer is determined by Gel Permeation Chromatography (GPC) analysis and is about 4500 g/mol. Nanocomposites (α-co-β-P/Clay 2, 5, 8, and 10% by weight of nano-clay) were synthesized by combining clay and α-co-β-P copolymer in solution using ultrasonic irradiation. This ultrasound-assisted method was employed to enhance and assess the structural, morphological, and thermal properties of the pure copolymer. The morphology of the resultant nanocomposites was characterized using infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) revealed that the nanocomposites exhibit a higher degradation temperature compared to the pure copolymer. The analyses provided evidence of the chemical modification of nano-clay layers and their uniform dispersion in the α-co-β-P copolymer matrix. Exfoliated structures were achieved for lower clay concentration (2% by weight), while intercalated structures and immiscible regions were observed for higher clay concentrations (5, 8, and 10% by weight). The antioxidant activity of α-pinene, β-pinene, and the obtained nanocomposites were studied using DPPH (2,2-diphenyl-1-picrylhydrazyl) as a model free-radical. The results demonstrate a significant antioxidant potential of the nanocomposites, showcasing their ability to effectively neutralize free-radicals. Finally, a novel procedure was devised for the rapid synthesis of copolymers and nanocomposites using α- and β-pinene. Full article

This study aimed to investigate vertical variations in dissolved organic matter (DOM) properties, humus (HS) composition, humic acid (HA) characteristics, and clay mineral dynamics, with a particular focus on the vertical distribution of HS components and mineral composition across Dark-brown, Meadow, and Paddy soil profiles. Results indicated that: (1) DOM in all three soil types was predominantly endogenous, primarily derived from microbial metabolism with minimal contributions from plant residues. (2) Vertical trends in DOM carbon content (C_DOM) were specific to soil type: in Dark-brown soil, C_DOM slightly increased from the Ap to Bt layer, followed by a sharp increase in the C layer; Meadow soil exhibited a significant decrease in C_DOM in the AB layer but remained relatively stable in other layers; Paddy soil showed a consistent decline in C_DOM with increasing depth. (3) HS and its fractions exhibited vertical variability: Paddy soil showed higher HS content in surface layers; carbon contents of water-soluble substances, HA, and humic-extracted acid (C_WSS, C_HA, and C_HE) decreased with depth in Dark-brown and Paddy soils, whereas they remained relatively stable in deeper layers of Meadow soil. (4) HA characteristics, including C/N ratio, functional groups, and aromaticity, were influenced by both depth and soil type: the Ap2 layer of Paddy soil effectively restricted the downward movement of organic matter; Fe³⁺ complexation played a key role in HA stabilization in Dark-brown soil; Meadow soil exhibited transitional HS properties. (5) Clay mineral assemblages were dominated by 2:1 type minerals (illite, smectite, illite–smectite interstratifications), showing distinct vertical weathering patterns: illite content decreased with depth due to hydrolysis, while proton-driven dissolution promoted kaolinite formation in surface layers, particularly in Dark-brown soil 2:1 minerals enhancing organic–mineral complexation in Meadow soil. The findings of this study provided a scientific basis for optimizing soil carbon pool management and offer insights into organic–mineral interactions that can enhance organic matter sequestration in agricultural soils. Full article

The present work aims at completing our previous comprehensive study on Ko-Kutani ware through the analysis, for the first time ever, of the renowned Hakuji bowl (white porcelain shallow bowl) excavated at the Noborigama kiln site in Kaga. The bowl had never been made available for such a purpose prior to this study owing to its absolute rarity, exceptional importance and fragile condition. Its shape and potting techniques, along with its materials, enabled both a direct comparison with the magnificent Ko-Kutani masterpieces belonging to the Ishikawa Prefectural Museum of Art collection and the groundbreaking identification of a definitive firing timeline marked by two distinct production stages: the Pre-Hakuji and Post-Hakuji phases. The crucial influence of the Hakuji bowl on Ko-Kutani production as a whole has been revealed for the first time ever, providing unprecedented and definitive evidence of the origin of the renowned and iconic porcelains. In consideration of the strict requirements and the absolute prohibition to sample or even touch any of the works of art, portable Energy-Dispersive X-Ray Fluorescence spectroscopy (pED-XRF) was selected as the most suitable technique for the type of materials to be investigated. Full article

In this study, highly ordered titanium dioxide nanotubes (TiO₂-NTs) have been synthesized using the electrochemical anodization procedure. Subsequently, the TiO₂-NTs were successfully decorated with PbS nanoparticles (NPs) using the pulsed KrF-laser deposition (PLD) technique under vacuum and under different Helium background pressures (P_He) ranging from 50 to 400 mTorr. The prepared samples (PbS-NPs/TiO₂-NTs) were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and UV–Vis and photoluminescence spectroscopies. XRD analyses confirmed that all TiO₂-NTs crystallized in the anatase phase, while the PbS-NPs crystallized in the cfc lattice. The average crystallite size of the (200) crystallites was found to increase from 21 to 33 nm when the pressure of helium (PHe) was raised from vacuum to 200 mTorr and then dropped back to ~22 nm at P_He = 400 mTorr. Interestingly, the photoluminescence intensity of the PbS-NPs/TiO₂-NTs samples was found to start diminishing for P_He ≥ 200 mTorr, indicating a lesser recombination rate of the photogenerated carriers, which also corresponded to a better photocatalytic degradation of the Amido Black (AB) dye. Indeed, the PbS-NPs/TiO₂-NTs samples processed at P_He = 200 and 300 mTorr were found to exhibit the highest photocatalytic degradation efficiency towards AB with a kinetic constant 130% higher than that of bare TiO₂-NTs. The PbS-NPs/TiO₂-NTs photocatalyst samples processed under P_He = 200 or 300 mTorr were shown to remove 98% of AB within 180 min under UV light illumination. Full article

The Klein–Nishina formula is used to calculate and investigate the electronic cross-section, atomic cross-section, and Compton mass attenuation coefficients for the human blood, breasts, eye lens, ovaries, and testis, using X-rays in the 0.1–20 MeV energy range. The effects of radiation energy, tissue effective charge number, tissue density, and tissue electronic density on these parameters were studied. The results show that the electronic cross-section and atomic cross-section decrease with increasing radiation energy. These parameters are found to be linearly increasing when the density and electron density of a tissue increase. This increase is more rapid with a bigger slope when the electron density increases as compared to the density of each tissue. A complex relationship between these coefficients and the effective charge number Z_eff of tissues is observed because Z_eff changes with the energy and linear attenuation coefficient of a tissue. The Compton mass attenuation coefficient is found to be dependent on the effective charge number to mass number ratio Z_eff/A_eff instead of just the effective charge number. This increase in the Compton mass attenuation coefficient with increasing Z_eff/A_eff is rapid for the lower values of Z_eff/A_eff. However, for a higher Z_eff/A_eff ratio, the increase is very slow and becomes almost constant for X-ray energies above 10 MeV. The calculated parameters are useful in determining radiation dose for the investigated tissues and their response to low and high-energy X-rays. The results and outcomes are also very useful in shielding and protecting tissues from the hazards of radiation. These parameters are also helpful in determining the scattered and optimum doses to improve image quality and treatment options in radiology and radiation therapy to offer the best care. Full article

Transition-metal oxides (TMOs) possess pronounced optoelectronic properties and are widely exploited in photovoltaics and photocatalysis. Here, we introduce a hot wire oxidation sublimation deposition (HWOSD) that directly converts elemental Mo and W into amorphous MoO_x and WO_x films on various substrates. Scanning electron microscopy and atomic force microscopy reveal uniform thickness and conformal coverage over textured and planar surfaces. X-ray photoelectron spectroscopy indicates high oxygen contents with stoichiometric ratios of 2.94 (MoO_x) and 2.91 (WO_x). Optical measurements show transmittances > 94% across 400–1200 nm, yielding optical band gaps of 1.86 eV (MoO_x) and 2.67 eV (WO_x). The conductivities of MoO_x and WO_x were 2.58 × 10⁻⁶ S cm⁻¹ and 5.14 × 10⁻⁷ S cm⁻¹ at room temperature, and the TMO/Si surface potential differences are 200 mV and 114 mV, respectively. Minority-carrier-lifetime measurements indicate that MoO_x films confer an additional passivation benefit to the i a-Si:H/c-Si/i a-Si:H stack. Annealing of MoO_x and WO_x realized their phase transition from an amorphous state to a polycrystalline state, with changes in their optical transmittance in the visible light region. Investigation of the photovoltaic performances of MoO_x and WO_x as HTLs deposited by HWOSD demonstrates their excellent electronic functionality in optoelectronics. These results establish HWOSD as a scalable, low-temperature method to fabricate high-quality TMO films and expand their potential in advanced optoelectronic devices. Full article

This study investigates the optimal duration for forming a uniform oxide layer and evaluates its influence on water-splitting performance. We selected a Ti₅₀Cu₃₂Ni₁₅Sn₃ amorphous ribbon, which is known to simultaneously form anatase TiO₂ and Sn oxide via a single hydrothermal process. Hydrothermal treatments were conducted at 220 °C in 150 mL of distilled water for durations of 3 and 6 h. The process successfully formed nanoscale metal oxides on the alloy surface, with the uniformity of the oxide layer increasing over time. The amorphous phase of the alloy was retained under all conditions. X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of TiO₂ and SnO_x, while Cu and Ni remained in their metallic state. Furthermore, we verified the coexistence of these oxides with metallic Ti and Sn. Photoelectrochemical analysis showed that the sample treated for 6 h exhibited the best water-splitting performance, which correlated directly with the most uniform oxide coverage. This time-controlled hydrothermal oxidation method, using only water, presents a promising and efficient approach for developing functional surfaces for electronic and photoelectrochemical applications of metallic glasses (MGs). Full article

Suspended microchannel resonators (SMRs) are powerful tools for mass, density, and viscosity sensing. Among various transduction methods, full piezoelectric transduction offers key advantages, including on-chip integration, low energy dissipation, and linear response. This work explores sub-200 nm Al_0.6Sc_0.4N thin films for SMR transduction, benchmarking them against their well-established AlN predecessor. By integrating the piezoelectric stack into low-stress silicon nitride (ls-SiN_x) beam resonators, we investigate the impact of bottom electrode design, photoresist removal prior to deposition, and deposition bias on film quality. Characterization includes X-ray diffraction (XRD), scanning electron microscopy (SEM), d₃₁ piezoelectric coefficient, relative dielectric permittivity, and breakdown field measurements. Results illustrate the impacts of the studied parameters and demonstrate a fourfold increase in d₃₁, compared to AlN, confirming the strong potential of Al_0.6Sc_0.4N for high-performance SMR transduction. Full article

Considering the current requirement for high temperatures and the significant energy consumption in the preparation of geopolymer-based cements, this paper presents a study on the compressive strength of metakaolin-based geopolymers containing various low-calcium fly ash admixtures, prepared at room temperature (25 ± 2 °C). The physical properties and microstructure of the geopolymers were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The type of alkaline cations, phase transformation, evolution of characteristic functional groups, and hydration characteristics of the microstructures were analyzed, and the hydration mechanism is discussed. The experimental results indicated that the fly ash content had a more significant impact on compressive strength than the alkaline cation type (Na⁺/K⁺). The optimal formulation (20% fly ash with 20% KOH activator) reached a compressive strength of 76.70 MPa at 28 days, which was around 6% higher than that of the NaOH-activated counterpart (72.34 MPa). Crystalline phase analysis in the transformation of mullite and microstructure analysis indicated that the increase in compressive strength could be attributed to the effective filling of the matrix interface by chemically inert fillers and the dense N-A-S-H and C-(A)-S-H multi-dimensional gel structures. These experiments prove the feasibility of using fly ash and metakaolin to prepare geopolymer materials with high compressive strength at room temperature. Full article

Background/Objectives: Bones are essential components of the human body, providing structural support, enabling mobility, storing minerals, and protecting internal organs. Bone fractures (BFs) are common injuries that result from excessive physical force and can lead to serious complications, including bleeding, infection, impaired oxygenation, and long-term disability. Early and accurate identification of fractures through radiographic imaging is critical for effective treatment and improved patient outcomes. However, manual evaluation of X-rays is often time-consuming and prone to diagnostic errors due to human limitations. To address this, artificial intelligence (AI), particularly deep learning (DL), has emerged as a powerful tool for enhancing diagnostic precision in medical imaging. Methods: This research introduces a novel convolutional neural network (CNN) model, the Multi-Level Feature Fusion Network (MLFNet), designed to capture and integrate both low-level and high-level image features. The model was evaluated using the Bone Fracture Multi-Region X-ray (BFMRX) dataset. Preprocessing steps included image normalization, resizing, and contrast enhancement to ensure stable convergence, reduce sensitivity to lighting variations in radiographic images, and maintain consistency. Ablation studies were conducted to assess architectural variations, confirming the model’s robustness and generalizability across data distributions. MLFNet’s high accuracy, interpretability, and efficiency make it a promising solution for clinical deployment. Results: MLFNet achieved an impressive accuracy of 99.60% as a standalone model and 98.81% when integrated into hybrid ensemble architectures with five leading pre-trained DL models. Conclusions: The proposed approach supports timely and precise fracture detection, optimizing the diagnostic process and reducing healthcare costs. This approach offers significant potential to aid clinicians in fields such as orthopedics and radiology, contributing to more equitable and effective patient care. Full article

Among different formations, inorganic/inorganic assemblies can be considered “two in one” systems offering collective and/or new physical-chemical properties and substantial activity. Herein, a post-synthetic approach involving the assembly through Van der Waals forces and/or hydrogen bonding of the preformed ZnO@OAm NPs and Ca(OH)₂@OAm NPs of non-uniform sizes (9 nm and 27 nm, respectively), albeit coated with the same surfactant (oleylamine-OAm), is reported. The resulting semiconductor hetero-nanostructure (named CaZnO) has been physicochemically characterized. The X-ray diffraction (XRD) peaks correspond to both ZnO and Ca(OH)₂, confirming the successful formation of a dual-phase system. Field emission scanning electron microscopy coupled with energy-dispersive spectroscopy (FESEM-EDS) of CaZnO indicated the formation of Ca(OH)₂ NPs decorated with irregular-shaped ZnO NPs. The synthesized hetero-nanostructure was evaluated by assessing any negative effects on the photosynthetic function of tomato plants as well as for the generation of reactive oxygen species (ROS). The impact of the CaZnO hetero-nanostructure on photosystem II (PSII) photochemistry was evaluated under both the growth light intensity (GLI) and a high light intensity (HLI) at a short (90 min) and long (96 h) duration exposure. An enhancement of photosystem II (PSII) function of tomato plants by 15 mg L⁻¹ CaZnO hetero-nanostructure right after 90 min was evidenced, indicating its potential to be used as a photosynthetic biostimulant, improving photosynthetic efficiency and crop yield, but pending further testing across various plant species and cultivation conditions. Full article

This study reports the successful synthesis of pure cobalt-substituted calcium molybdate powders (Co-doped CaMoO₄) through a co-precipitation method conducted at room temperature, without the use of surfactants or hazardous organic solvents. The formation of solid solutions with x values ranging from 0.00 to 0.08 was confirmed by X-ray diffraction, Rietveld refinement, and Raman spectroscopy analyses. Elemental analysis using energy-dispersive X-ray spectroscopy showed a strong correlation between the experimental and nominal stoichiometries. The synthesized molybdate powders consist of micrometer-sized particles exhibiting diverse morphologies, including microspheres, flower-like architectures, and dumbbell-shaped particles. These agglomerates are composed of primary particles smaller than 43 nm. The specific surface area increased from 3.59 m²/g for the undoped CaMoO₄ to 10.74 m²/g for the 6% Co-doped CaMoO₄. These nanostructured powders represent promising host materials for 4f ions, making them potential candidates for solid-state lighting applications. Full article

This article proposes a novel three-dimensional trench electrode detector, named the through-type three-dimensional quasi-hemispherical electrode detector. The detector adopts a trench structure to package each independent unit and achieves complete penetration of trench electrodes with the help of an SOI substrate. The horizontal distances from the center anode of the detector to the trench cathode and the detector thickness are equal. It has a near-spherical structure and exhibits spherical-like electrical performance. In this study, we modeled the device physics of the new structure and conducted a systematic three-dimensional simulation of its electrical characteristics, including the electric field, electric potential, electron concentration distribution of the detector, the inducted current caused by incident ions, and the crosstalk between detector units. Computational and technology computer-aided design (TCAD) simulation results show that the detector has an ultra-small capacitance (2.7 fF), low depletion voltage (1.4 V), and uniform electric field distribution. The trench electrodes electrically isolate the pixel units from each other so that the coherence effect between the units is small and can be applied in high-resolution X-ray photon counting detectors to enhance the contrast-to-noise ratio of low-dose imaging and the detection rate of tiny structures, among other things. Full article