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The isotopic composition of ruthenium (Ru) in individual presolar silicon carbide (SiC) stardust grains bears the signature of s-process nucleosynthesis in asymptotic giant branch stars, plus an anomaly in 99Ru that is explained by the in situ decay of technetium isotope 99Tc in the grains. This finding, coupled with the observation of Tc spectral lines in certain stars, shows that the majority of presolar SiC grains come from low-mass asymptotic giant branch stars, and that the amount of 99Tc produced in such stars is insufficient to have left a detectable 99Ru anomaly in early solar system materials.
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http://dx.doi.org/10.1126/science.3030649 | DOI Listing |
ACS Appl Mater Interfaces
September 2025
State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, Zhejiang 310058, China.
We report an electro-enhanced catalytic etching approach for direct atomic-level patterning of single-crystal 4H-SiC (0001) surfaces. The process utilizes platinum-coated probes under a negative sample bias, which enhances catalytic reactions and promotes etching of SiC without additional mechanical load. Unlike traditional etching approaches that rely on hazardous chemicals such as hydrofluoric acid, this approach operates under ambient conditions, offering improved safety and environmental compatibility.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2025
School of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Long Teng Road, Shanghai 201620, P.R. China.
Silicon carbide (SiC) membranes combine exceptional chemical, thermal, and mechanical stability but suffer from surface inertness that precludes functionalization. Conversely, MOFs offer unmatched molecular selectivity but are typically powders, severely limiting their practical use. To address this, we develop a generalizable route to fabricate ultrastable MOF@SiC membranes via sequential oxidation and acidification, creating abundant Si-OH sites on SiC surfaces that covalently bond with Zr-MOF crystals; the bonding mechanism between MOFs and substrates has been extensively studied.
View Article and Find Full Text PDFSci Prog
September 2025
School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai, China.
To address the growing demand for temperature control precision and uniformity in wafer processing, a specialized electrostatic chuck temperature control system based on thermal control coatings is proposed, aiming to enhance thermal management robustness and homogeneity. This study employs a zoned control methodology using metal-oxide conductive coatings on silicon carbide wafer heating plates. A quadrant-based thermal control coating model was established, and finite element analysis was conducted to compare temperature distribution characteristics across three geometric configurations: sectorial, spiral, and zoned designs.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2025
Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084, China.
Silicon carbide (SiC) has attracted considerable interest for use in electronics, aerospace, and nuclear energy applications owing to its excellent electrical and mechanical properties. In the nuclear industry, SiC serves as an effective tritium permeation barrier. However, a significant discrepancy remains between the experimentally measured diffusion coefficients and the theoretical predictions.
View Article and Find Full Text PDFNanotechnology
September 2025
State Key Laboratory of Optoelectronic Materials and Technologies School of Chemistry and Chemical Engineering, Sun Yat-Sen University, No 135, XinGangXi Road, Guangzhou 510275, guangzhou, 510275, CHINA.
Silicon carbide nanowires (SiC NWs) combine the benefits of bulk SiC materials with the properties of low-dimensional nanomaterials. They are known for their excellent mechanical strength and durability, which are critical for their potential applications in high-stress environments and micro-nano functional systems. Here, the mechanical properties and deformation mechanisms of 2H-SiC NWs with rare defects in the [0001] orientation are reported.
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