Bulletin of Materials Science最新文献

As the use of natural biomaterials has gained more attention, many natural resources—including the tea polyphenol (TP)—have come into focus. Green tea contains a type of natural plant polyphenol, TP, which has excellent properties. These include hydrophobicity, antibacterial, antioxidant, anti-ultraviolet, antiviral, antidiabetic, anti-ageing, anticancer, antitumor and anti-inflammatory properties that others lack. In this review, we first discuss the structure and properties of TP. Furthermore, we examine recently developed TP-based advanced composite materials that incorporate polymers such as polyacrylonitrile, polyaniline, polylactic acid and polyvinyl alcohol, as well as natural materials like chitosan, starch, pomelo peel gelatin and reduced graphene oxide. This review focuses on their structure, properties, and various applications in fields such as food packaging, cosmetics, medicine, health products, and flexible strain sensors, among others.

Crop straw is a kind of renewable resource with great application potential, which has the characteristics of a wide source, abundant reserves and low price. Using straw as a raw material and a hydrothermal process to prepare high-function carbon-based material, it is an economic and green way to promote straw resource utilization. In this article, the influencing factors in the preparation process of straw hydrothermal carbon were reviewed. The influences of process parameters such as straw carbon source, hydrothermal time, hydrothermal temperature and solid–liquid ratio on the structural properties of hydrothermal carbon were emphasized. The regulation of the morphology and structure of carbon by activators such as KOH and KMnO₄ were analysed. At the same time, the application of straw-based hydrothermal carbon in the field of environmental pollution control, catalysis and electrochemistry is summarized. Finally, it is pointed out that the future research should focus on the structure control method, green activation technology of straw-based hydrothermal carbon and the preparation of hydrothermal carbon from mixed straw, and further improve the stability of the porous structure of the hydrothermal carbon and the interference-free in the practical application environment, so as to realize the commercial application of straw-based hydrothermal carbon.

Tungsten oxide (WO₃) has recently gained attention as an electrochromic material for dynamic display technologies, particularly advertising, due to its tunable optical and electrochemical properties. In this study, we compared WO₃ with titanium dioxide (TiO₂) coatings and commercial display films. WO₃ layers with thicknesses of 2, 4, and 6 nm were fabricated using a surfactant-assisted spray pyrolytic method to ensure uniformity and adhesion. TiO₂ coatings served as controls. To confirm the monoclinic phase of WO₃, X-ray diffraction was performed. Optical performance was assessed through UV–Vis–NIR transmission and reflection spectra, while electrochemical behaviour was measured using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Durability testing included monitoring transmission and charge insertion/extraction over cycling, alongside environmental stability assessments. An economic evaluation compared Material and operational costs. At 6 nm, TiO₂ films achieved a sharpness score of 70, 75% contrast and 80% colour purity, with transmittance of 55% and colouration efficiency of 0.65 cm²/C. Their switching time was 15 s, and performance degraded significantly after extended cycling, including delamination beyond 50,000 cycles. By contrast, WO₃ films showed higher transmittance (70%), faster switching (12 s), and better colouration efficiency (0.75 cm²/C). They also exhibited more stable charge density retention, improved ion mobility, and stronger current responses in voltammetry. Overall, WO₃ films demonstrated superior optical clarity, faster response, and better durability compared to TiO₂. These findings suggests that WO₃ is a promising, cost-effective material for next-generation electrochromic displays in advertising applications.

This study explores the effect of zinc oxide (ZnO) nanomaterial doping on the electro-optical properties of 5CB-coded nematic liquid crystals and predicts these properties using machine learning algorithms. We produced seven composite structures with varying ZnO doping ratios and measured their electro-optical transmittance. Furthermore, a prediction model using four different machine learning algorithms (k-Nearest Neighbors, Decision Tree, Random Forest, and Extra Trees) was developed, which predicts optical transmittance as a function of voltage and doping ratio. The Extra Trees algorithm demonstrated the best prediction accuracy, achieving an R² value of 91% on the experimental dataset. Subsequently, a new composite with a different doping ratio was then experimentally prepared and measured to validate the model, which was trained on the experimental dataset. This study highlights the utility of machine learning for predicting the electro-optical characteristics of doped liquid crystal structures, resulting in considerable time and resource savings in experimental procedures.

In this article, the theoretical background of MASnBr₃ and Cs₂TiBr₆ was carried out using density functional theory (DFT) by evaluating the electronic properties through the frontier molecular orbital, UV–visible absorption spectra and density of state spectra. Also, a simulation was conducted to optimize a proposed solar cell to improve the performance of perovskite solar cells (PSCs). This cell is composed of six stacked materials, namely FTO/ETL/MASnBr₃/Cs₂TiBr₆/HTL/Au, and features a double active layer consisting of two perovskites, MASnBr₃ and Cs₂TiBr₆. The simulations were carried out using the SCAPS-1D software. Initially, the impact of the electron transport layer (ETL) on the cell’s output parameters was analysed using different materials, such as ZnO, SnO₂, WS₂, PCBM, C60, CdS, TiO₂, CdZnS and ZnSe. Additionally, the effect of the HTL on the photovoltaic parameters of the cell was studied using materials such as MoO₃, CuSCN, NiO, CuSbS₂, Cu₂O, CuI, CuO, PEDOT:PSS, Cs₂TiBr₆ and P3HT. Subsequently, the thickness and doping density of the two active layers were optimized. The thickness and doping density of the ETL and HTL were also optimized. Finally, the effect of different materials on the cell’s performance was examined. The cell demonstrated remarkable performance, achieving parameters such as the open-circuit voltage V_oc = 1,22 V, J_sc = 33,76 mA cm^–2, FF = 89,40% and PCEs = 36,81% for the optimized parameters, including a ZnSe ETL, a MoO₃ HTL with a thickness of 100 nm and a doping density of 10²¹ cm^–3, a thickness of 1000 nm for MASnBr₃ and 400 nm for Cs₂TiBr₆.

Superprismane is a porous, three-dimensional carbon allotrope that combines super-hardness, ductility and low effective-mass charge carriers attributes that make it promising for blue-to-UV optoelectronics and high performance structural applications. In this work, we employ the M-polynomial framework to extract complete closed-form expressions for seven classical Zagreb-type topological indices and their seven multiplicative counterparts for an arbitrary (ptimes k) superprismane lattice. Three-dimensional index surfaces are visualized and benchmarked against two canonical carbon networks ({6.8}^{2};text{D}) and graphite. Using least-squares regression, we demonstrate that the multiplicative inverse-sum index achieves a perfect correlation ((r=1.00)) with shear modulus and an almost perfect correlation ((r=0.99)) with Young’s modulus, outperforming all other descriptors. These results show that M-polynomial-derived indices provide a rapid, inexpensive alternative to density-functional calculations for predicting bulk mechanical properties, enabling high-throughput computational screening of novel carbon materials. The study closes a gap in the literature by delivering the first comprehensive suite of additive and multiplicative indices for a three-dimensional porous carbon network and establishes a foundation for data-driven design of advanced allotropes.

The present study concerns the understanding of the effect of beam oscillation on electron beam welded AISI 304 stainless steel. The effect of beam oscillation on the microstructure, mechanical properties and electrochemical properties of electron beam welded AISI 304 stainless steel has been analysed. Welding was carried out using an 80 kV, 12 kW electron beam welding unit, using a static beam and an oscillated beam of varied oscillation diameters (1 and 2 mm). The weld morphology in terms of microstructure and residual stress developed in the weld zone was evaluated. A static beam led to the formation of skeletal dendrites in the fusion zone, while the application of an oscillated beam developed a combination of dendrites of lathy and skeletal morphology. The residual stress developed in the fusion zone and heat-affected zone was meticulously measured and was found to vary with welding parameters. The hardness measurement showed a marginally higher microhardness in the fusion zone when beam oscillation was applied (250 VHN) as compared to static beam (245 VHN). Tensile strength variation shows that an oscillated beam offers a higher yield strength (281–270 MPa) and ultimate tensile strength (785–794 MPa) as compared to the static beam (263 and 751 MPa). The percentage elongation in the weld zone developed with an oscillated beam was 127%, which was 21% higher than that of static beam weld (106%). The electrochemical corrosion behaviour also showed a superior corrosion resistance of the weld zone when beam oscillation was applied. The enhancement of mechanical and electrochemical properties developed by oscillated beams has been stated.

Austenitic stainless steel 316L (AISI 316L) is commonly employed in marine applications. However, this substrate is exposed to wear and corrosion conditions. To protect AISI 316L substrate from wear and corrosion attacks, it could be coated. In this study, diamond-like carbon (DLC) films were deposited on nitriding AISI 316L substrate. Then, the adhesion, hardness, wear and corrosion resistance of the DLC coated samples were studied. The coating was characterized by X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (RS) and field emission scanning electron microscopy (FESEM) and nano-indentation methods. Plasma nitriding treatment increased the adhesion of the DLC coating on the AISI 316L substrate. Electrochemical measurements and wear tests showed that deposition of the DLC coating improved corrosion and wear resistance of the AISI 316L substrate.

Chloride ions in the chemical, nuclear, pharmaceutical, food, marine, petrochemical industries, and body fluid medium cause pitting corrosion in stainless steel (SS). In this research, the pitting corrosion resistance behaviour of SS 304L was evaluated in simulated marine environment (SME) and simulated body fluid (SBF) solutions. A solution annealed coarse-grain (CG) SS 304L was severely plastic deformed (SPD, up to 90%) at liquid N₂ temperature. This leads to the formation of ultra-fine grain (UFG) microstructure. UFG specimens were further annealed at 1050°C for 1-h, and gamma-ray irradiated separately at a dose of 7 kGy. Pitting was evidenced for the as-received CG, UFG-deformed and UFG-deformed, followed by annealed (1050°C for 1 h) specimens, whereas pitting corrosion was not observed for the UFG specimen after gamma-ray irradiation in both SME and SBF solutions.

In this report, the structural, morphological and electro-optical analysis of 2-D graphitic carbon nitride (g-C₃N₄) nano-sheets has been performed. The g-C₃N₄ nano-sheets were synthesized based on the thermal calcination process and characterized by transmission electron microscopy (TEM). X-ray diffraction studies (XRD) showed the inter-layer spacing to be 0.323 nm for the (002) plane which is 3.5% more dense than crystalline graphite and higher than literature reports for g-C₃N₄. For the evaluation of electro-optical properties, we have utilized time-domain spectroscopy for the frequency range 0.2 to 2 THz. The complex reflective indices (n, k) and permittivity ((epsilon , epsilon {prime})) for g-C₃N₄ have been determined. The complex conductivity has been observed to increase monotonically with an increase in frequency. The mobility of g-C₃N₄ has been theoretically estimated. The terahertz band properties such as plasma frequency, damping rate (0.095 THz), and collision time, were calculated for the synthesized material. The high permittivity value for g-C₃N₄ as reported in this work is promising for THz frequency selective components such as resonators, absorbers and collimators.