Applied Research最新文献

The absorption spectra of various sizes of nanoparticles of copper (Cu), silver (Ag), and gold (Au) are theoretically investigated. The density functional theory (DFT), time-dependent DFT (TDDFT), and real-time TDDFT are used to demonstrate how size and shape affect their optical properties and how these are evolved as the number of atoms increases. For this reason, the focus was turned on almost spherical nanoparticles cut out from the corresponding crystal structure (called 0D), elongated ones (1D), and flattened ones (2D). The nature of the observed absorption peaks is further analyzed with the help of transition contribution maps and induced density plots which help us identify the emergence of probable plasmonic resonances as the size of the nanoparticles increases.

In this paper, molecular dynamics (MD) simulations and machine learning (ML) methods are combined to obtain the transport properties, such as viscosity and thermal conductivity, of five basic elements, which are computationally hard to obtain at the nanoscale and extremely demanding to estimate accurately through an experimental procedure. Starting from an experimental database from literature sources, we extend the (P-T) space on which the transport properties are calculated by employing MD simulations and ML predictions, in a synergistic mode. Results refer to all fluid states (gas, liquid, supercritical), under ambient and supercritical conditions, suggesting an alternative path that can be accurately followed to bypass expensive experiments and costly numerical simulations. Nine different ML algorithms are exploited and assessed on their prediction ability, with tree-based architectures achieving increased accuracy on the implied data set. The proposed computational platform runs fast in a common python Jupyter environment, both for MD and ML, and can be adjusted and extended for the calculation of material properties both in interpolation and extrapolation applications.

Over the past several years, atomically thin two-dimensional carbides, nitrides, and carbonitrides, otherwise known as MXenes, have been expanded into over fifty material candidates that are experimentally produced, and over one hundred fifty more candidates that have been theoretically predicted. They have demonstrated transformative properties such as metallic-type electrical conductivities, optical properties such as plasmonics and optical nonlinearity, and key surface properties such as hydrophilicity, and unique surface chemistry. In terms of their applications, they are poised to transform technological areas such as energy storage, electromagnetic shielding, electronics, photonics, optoelectronics, sensing, and bioelectronics. One of the most promising aspects of MXene's future application in all the above areas of interest, we believe, is reliably developing their flexible and bendable electronics and optoelectronics by printing methods (henceforth, termed as printed flexible MXetronics). Designing and manipulating MXene conductive inks according to the application requirements will therefore be a transformative goal for future printed flexible MXetronics. MXene's combined property of high electrical conductivity and water-friendly nature to easily disperse its micro/nano-flakes in an aqueous medium without any binder paves the way for designing additive-free highly conductive MXene ink. However, the chemical and/or structural and hence functional stability of water based MXene inks over time is not reliable, opening research avenues for further development of stable and conductive MXene inks. Such priorities will enable applications requiring high-resolution and highly reliable printed MXene electronics using state-of-the art printing methods. Engineering MXene structural and surface functional properties while tuning MXene ink rheology in benign solvents of choice will be a key for ink developments. This review article summarizes the present status and prospects of MXene inks and their use in inkjet-printed (IJP) technology for future flexible and bendable MXetronics.

Recently, rhenium (Re) based ohmic contacts to GaN have been studied for their low resistivity, smooth surface morphology, and sharp edge acuity at low annealing temperatures. In this work, we discuss the evolution of surface microstructures for Re-Al-Ni-Au ohmic contacts on n-GaN as a function of Re layer thickness and annealing temperature. For all Re thicknesses, the Al and Ni segregate into agglomerates that increase in size with increasing annealing temperature. These agglomerates are surrounded by Al-Au films. Along with the underlying Re layer, they form different crystallographic phases of Re-Al-Ni, Al₆Re, AlAu₂, and Al₂Au₅. This, along with the formation of Re-N phases at the metal-semiconductor interface leads to low resistivity ohmic contacts on n-GaN. Investigating the evolution of the contact microstructure is an important step in understanding the behavior of the Re-based ohmic contact system.

The development of metal matrix composites is important for industrial applications that require lightweight materials with high strength, stiffness, and wear resistance. In this investigation, Al2024 alloy was reinforced with fly ash and silicon (SiC) carbide hybrid composites using the stir-squeeze cast technique. Two sets of composites were fabricated: one with 3 wt% fly ash and 3 wt% SiC, and the other with 3 wt% fly ash, 5 wt% SiC, and 3 wt% fly ash, 7 wt% SiC The composites were prepared using 25 and 75 mm diameter dies. Microstructural characterization of the specimens was performed using scanning electron microscope, X-ray powder diffraction, and energy dispersive X-ray spectroscopy analysis. Mechanical properties, such as yield strength, ultimate tensile strength, and hardness, were determined according to American Society for Testing and Materials standards. The hybrid composites fabricated in the 25 mm diameter cast iron molds exhibited superior mechanical properties compared to those prepared in the 75 mm diameter molds. The addition of fly ash and SiC particulates enhanced the mechanical properties of the Al2024 alloy. These composites showed improved strength, toughness, and ductility.

Saccharomyces cerevisiae LBTF 21.3, Pichia manshurica LBTF 21.1, and Leuconostoc lactis LBTF 21.1 were used as single and mixed cultures in coffee fermentations. Fermentations carried out in glass jars with P. manshurica LBTF 21.1/Leuc. lactis LBTF 21.1 showed higher fermentation rates than S. cerevisiae LBTF 21.3/P. manshurica LBTF 21.1 or S. cerevisiae LBTF 21.3/Leuc. lactis LBTF 21.1. The highest cup quality was reached with P. manshurica LBTF 21.1/Leuc. lactis LBTF 21.1 (83.0 points). Full factorial design (2²) carried out with P. manshurica LBTF 21.1 revealed that the higher proportion of water added before the fermentation resulted in higher production of acetic acid. A contrary effect of this variable was observed on the production of lactic acid with Leuc. lactis LBTF 21.1. Fermentations conducted in bioreactor evidenced the production of acetaldehyde by P. manshurica LBTF 21.1/Leuc. lactis LBTF 21.1, P. manshurica LBTF 21.1, and Leuc. lactis LBTF 21.1. Additionally, the highest cup quality was reached in fermentations with P. manshurica LBTF 21.1 (82.5 points) followed by Leuc. lactis LBTF 21.1 (81.5 points) and P. manshurica LBTF 21.1/Leuc. lactis LBTF 21.1 (81.0 points). Fermentations of coffee with single and mixed cultures are interesting strategies for the improvement of the sensory quality.

An important process step in carbon fiber production is the stabilization of the pan precursor fiber, which makes it infusible and incombustible. This article gives a market overview of the carbon fiber producers relating to their used oxidations oven and of market of oxidations oven itself. All six industrially available oxidation oven types are described and an overview of the oven supplier is given. The analysis of the oxidation oven market shows that only three out of six oxidation oven technologies are used for large-volume production. CtE is currently the most widely used oven technology with approximately 55%. Since 2014, CF demand has been growing faster than the expansion of production capacities. A shortage is predicted within the next 5 years. In addition, the production capacities of existing CF lines have stagnated at an average of 1.5 kt*a⁻¹ since the last 10 years. To meet the increasing CF demand in the coming years, various options are available: (1) Increasing large-tow production, (2) Increasing process speed (3) Increasing the loading factor (4) Increasing with of oxidation oven.

Diaryliodonium salts (Ar₂I⁺X⁻) are used as a photosensitive initiator that generates acid or radical species by ultraviolet light irradiation. Recently, sensitization of Ar₂I⁺X⁻ has gained importance owing to the escalating demand for high-sensitive initiators with longer wavelength absorption such as 365 and 436 nm. However, the mechanism of photolysis of Ar₂I⁺X⁻ has not been strictly elucidated. This paper shows discussions of the details of its mechanism. Herein, we analyzed the photosensitization of Ar₂I⁺X⁻ with 2–isopropylthioxanthone (ITX) based on transient absorption techniques. As a result, it was revealed that electron transfer occurred from a triplet excited state of ITX to Ar₂I⁺X⁻ with an electron transfer rate constant of 4.2 × 10⁹ s⁻¹. Furthermore, high performance liquid chromatography measurements found the quantum yield of the photolysis was determined to be 0.48.

Despite the unique advantages a doubly fed induction generator (DFIG) offers to the grid-integrated renewable energy systems, they have a limitation of being susceptible to grid fault as their stator windings are directly connected to the grid. The fault current limiters (FCLs) provide a sustainable solution by enhancing the fault ride-through capability and thus it improve the transient performance of a DFIG. In this work, a multi-inductor-based H-bridge fault current limiter (HBFCL) is proposed to augment the transient performance of a DFIG. The operational efficacy of the HBFCL is evaluated through the administration of both symmetrical and asymmetrical fault scenarios. The effectiveness of the HBFCL is further investigated by comparing the performance of the HBFCL with that of the bridge-type series dynamic braking resistor (BSDBR). Both the graphical and numerical interpretations of the simulation result assert that the HBFCL improves the transient performance of a DFIG-based wind farm and outweighs the performance of the BSDBR in all aspects.

The cover features a tree named “photopolymerization” that grows exceptionally lush and beautiful under the sunlight. The sunlight represents three different light sources, categorizing the photopolymerization technology into three domains: UV, visible, and NIR. The luxuriant branches and leaves resemble the broad applicability of photopolymerization technology. This overview briefly introduces the application of photopolymerization technology in five areas: thiol-ene polymerization, photoinduced controlled/living polymerizations (CLPs), 3D printing, UV nanoimprint lithography photoresist, and hydrogels, highlighting the irreplaceable role of photopolymerization technology in today's world. Read the article here: https://onlinelibrary.wiley.com/doi/10.1002/appl.202300030.