Through the reactive melt infiltration technique, C/C-SiC-(ZrxHf1-x)C composites were produced. A thorough investigation into the C/C-SiC-(ZrxHf1-x)C composites' ablation behavior, microstructural evolution, and the associated porous C/C skeleton microstructure was performed. Analysis of the C/C-SiC-(ZrxHf1-x)C composites reveals a primary composition of carbon fiber, carbon matrix, SiC ceramic, (ZrxHf1-x)C, and (ZrxHf1-x)Si2 solid solutions. Optimizing the pore structure is advantageous for the production of (ZrxHf1-x)C ceramic. C/C-SiC-(Zr₁Hf₁-x)C composites showcased exceptional ablation resistance when subjected to an air plasma near 2000 degrees Celsius. CMC-1's ablation, conducted for a duration of 60 seconds, resulted in the lowest mass and linear ablation rates, quantified at 2696 mg/s and -0.814 m/s, respectively, contrasting with the higher rates seen in CMC-2 and CMC-3. Formation of a bi-liquid phase and a liquid-solid two-phase structure on the ablation surface during the process impeded oxygen diffusion, thereby retarding further ablation, and thus the superior ablation resistance of the C/C-SiC-(Zr<sub>x</sub>Hf<sub>1-x</sub>)C composites is explained.
Employing banana leaf (BL) and stem (BS) biopolyols, two distinct foam samples were created, and their mechanical response to compression and internal 3D structure were examined. X-ray microtomography's 3D image acquisition procedure incorporated traditional compression and in situ testing. A methodology encompassing image acquisition, processing, and analysis was created to classify foam cells, determine their quantities, volumes, and shapes, incorporating the compression techniques. selleck While comparable in their compression reactions, the average cell volume of the BS foam was five times more substantial than that of the BL foam. Furthermore, compression was observed to correlate with an increase in cell count, yet a concomitant decrease in average cellular volume. The cells' elongated shapes were unaffected by the compression. The possibility of cell collapse offered a potential explanation for these attributes. By using the developed methodology, a wider study of biopolyol-based foams is possible, investigating their potential as a replacement for petroleum-based foams that is greener.
We introduce a comb-like polycaprolactone-based gel electrolyte for high-voltage lithium metal batteries. This electrolyte is synthesized from acrylate-terminated polycaprolactone oligomers and a liquid electrolyte, and its electrochemical performance is discussed. The ionic conductivity of this gel electrolyte at room temperature was found to be 88 x 10-3 S cm-1, a very high value, more than adequate for the stable cycling process of solid-state lithium metal batteries. selleck The observed lithium ion transference number of 0.45 helped control concentration gradients and polarization, thereby preventing lithium dendrites from forming. The gel electrolyte's oxidation potential extends to a remarkable 50 volts against Li+/Li, and it seamlessly integrates with metallic lithium electrodes. A high initial discharge capacity of 141 mAh g⁻¹ and a remarkable capacity retention exceeding 74% of the initial specific capacity are displayed by LiFePO4-based solid-state lithium metal batteries, attributable to their superior electrochemical properties, after 280 cycles at 0.5C, tested at room temperature. This paper describes a remarkably effective in-situ gel electrolyte preparation technique, yielding an outstanding gel electrolyte ideal for high-performance lithium metal battery applications.
Uniaxially oriented, high-quality, and flexible PbZr0.52Ti0.48O3 (PZT) films were created on RbLaNb2O7/BaTiO3 (RLNO/BTO)-coated, flexible polyimide (PI) substrates. Employing KrF laser irradiation, a photo-assisted chemical solution deposition (PCSD) process was used to fabricate all layers, enabling the photocrystallization of the printed precursors. As seed layers for the uniaxially oriented growth of PZT films, Dion-Jacobson perovskite RLNO thin films were employed on flexible PI sheets. selleck The fabrication of the uniaxially oriented RLNO seed layer involved a BTO nanoparticle-dispersion interlayer to avert PI substrate damage under excessive photothermal heating, and RLNO growth was restricted to approximately 40 mJcm-2 at 300°C. A precursor film derived from a sol-gel process, irradiated by a KrF laser at 50 mJ/cm² and 300°C on BTO/PI with flexible (010)-oriented RLNO film, enabled the growth of PZT film. Only the uppermost region of the RLNO amorphous precursor layer exhibited uniaxial-oriented growth of RLNO. The amorphous and oriented phases within RLNO are vital in the production of this multilayered film system; their roles include (1) instigating the oriented growth of the PZT layer above and (2) reducing stress within the BTO layer below, hence mitigating micro-crack generation. The first instances of PZT film crystallization have occurred directly on flexible substrates. A cost-effective and high-demand approach to fabricating flexible devices involves the coupled processes of photocrystallization and chemical solution deposition.
The optimal ultrasonic welding (USW) technique for PEEK-ED (PEEK)-prepreg (PEI impregnated CF fabric)-ED (PEEK)-PEEK lap joints was deduced through an artificial neural network (ANN) simulation, incorporating a dataset expanded by expert input from the initial experimental data. Empirical testing of the simulation's projections showcased that mode 10 (900 milliseconds, 17 atmospheres pressure, 2000 milliseconds duration) exhibited the characteristics of high strength and preserved the structural integrity of the carbon fiber fabric (CFF). The study found that the multi-spot USW method, configured at the optimal mode 10, successfully fabricated the PEEK-CFF prepreg-PEEK USW lap joint, demonstrating its capacity to withstand 50 MPa load per cycle, corresponding to the lowest high-cycle fatigue threshold. Using the USW mode in ANN simulation, with neat PEEK adherends, did not result in bonding between particulate and laminated composite adherends, incorporating CFF prepreg reinforcement. The USW lap joints could be fabricated by lengthening USW durations (t) to a maximum of 1200 and 1600 ms, respectively. In this particular instance, the upper adherend is the pathway for a more effective transfer of elastic energy to the welding zone.
The conductor's composition is defined by an aluminum alloy, including 0.25 weight percent zirconium. Our investigations centered on alloys that were additionally strengthened by the inclusion of X, specifically Er, Si, Hf, and Nb. The alloys' fine-grained microstructure was a result of equal channel angular pressing and rotary swaging procedures. Evaluating the thermal stability, specific electrical resistivity, and microhardness of novel aluminum conductor alloys was the aim of this study. During the annealing process of fine-grained aluminum alloys, the mechanisms governing the nucleation of Al3(Zr, X) secondary particles were investigated using the Jones-Mehl-Avrami-Kolmogorov equation. The analysis of grain growth data in aluminum alloys, guided by the Zener equation, produced the relationship between annealing time and the average secondary particle sizes. Annealing at a low temperature (300°C) for a significant duration (1000 hours) revealed a preference for secondary particle nucleation at the cores of lattice dislocations. Annealing the Al-0.25%Zr-0.25%Er-0.20%Hf-0.15%Si alloy for an extended period at 300°C produces an optimal balance between microhardness and electrical conductivity (598% International Annealed Copper Standard, Hv = 480 ± 15 MPa).
All-dielectric micro-nano photonic devices, fashioned from high-refractive-index dielectric materials, present a low-loss environment for manipulating electromagnetic waves. Focusing electromagnetic waves and generating structured light are among the remarkable feats enabled by the manipulation of electromagnetic waves using all-dielectric metasurfaces. Advancements in dielectric metasurfaces are strongly associated with bound states within the continuum, exhibiting non-radiative eigenmodes that extend beyond the light cone, reliant on the metasurface's attributes. This investigation introduces an all-dielectric metasurface structured with periodically arranged elliptic pillars, demonstrating that the displacement of an individual elliptic pillar modulates the intensity of light-matter interactions. Elliptic cross pillars with C4 symmetry result in an infinite quality factor for the metasurface at that point, a phenomenon also known as bound states in the continuum. A disruption of the C4 symmetry, effected by displacing a single elliptic pillar, triggers mode leakage within the associated metasurface; despite this, the high quality factor still exists, termed quasi-bound states in the continuum. A simulation study demonstrates that the engineered metasurface exhibits a sensitivity to changes in the refractive index of the environment, implying its potential in refractive index sensing. Additionally, the information encryption transmission is successfully accomplished by leveraging the specific frequency and refractive index variation of the medium around the metasurface. We expect that the designed all-dielectric elliptic cross metasurface's sensitivity will propel the progress of miniaturized photon sensors and information encoders.
Selective laser melting (SLM) was used to create micron-sized TiB2/AlZnMgCu(Sc,Zr) composites, utilizing directly blended powders in this paper. TiB2/AlZnMgCu(Sc,Zr) composite samples, created using selective laser melting (SLM) and possessing a density exceeding 995%, were found to be crack-free, and their microstructure and mechanical properties were investigated thoroughly. Introducing micron-sized TiB2 particles into the powder is shown to enhance laser absorption, subsequently reducing the energy density needed for Selective Laser Melting (SLM) and ultimately improving densification. Although some TiB2 crystals formed a unified structure with the matrix, other TiB2 particles remained fractured and unconnected; however, the presence of MgZn2 and Al3(Sc,Zr) can effectively create intermediate phases, linking these non-coherent surfaces with the aluminum matrix.