The superconducting critical temperature of HS ranks among the highest measured, at 203 K. This impressive value stems from a singularity in the electronic density-of-states, induced by a flat-band region that consists of saddle points. The peak sits right at the Fermi level, so that it gives rise to a giant electron-phonon coupling constant. In this work, we show how atomic orbital interactions and space group symmetry work in concert to shape the singularity. The body-centered cubic Brillouin Zone offers a unique 2D hypersurface in reciprocal space: fully connecting squares with two different high-symmetry points at the corners, Γ and H, and a third one in the center, N. Orbital mixing leads to the collapse of fully connected 1D saddle point lines around the square centers, due to a symmetry-enforced s-p energy inversion between Γ and H. The saddle-point states are invariably nonbonding, which explains the unconventionally weak response of the superconductor's critical temperature to pressure. Although HS appears to be a unique case, the theory shows how it is possible to engineer flat bands and singularities in 3D lattices through symmetry considerations.
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Angew Chem Int Ed Engl
December 2024
Fuzhou University, Chemistry, 523 Gongye Rd, Gulou, 350000, Fuzhou, CHINA.
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View Article and Find Full Text PDFSci Rep
December 2024
Agricultural Engineering Department, Faculty of Agriculture and Natural Resources, Aswan University, Aswan, 81528, Egypt.
Efficient cooling systems are critical for maximizing the electrical efficiency of Photovoltaic (PV) solar panels. However, conventional temperature probes often fail to capture the spatial variability in thermal patterns across panels, impeding accurate assessment of cooling system performance. Existing methods for quantifying cooling efficiency lack precision, hindering the optimization of PV system maintenance and renewable energy output.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Purdue University, Davidson School of Chemical Engineering, 480 Stadium Mall, 47907, West Lafayette, UNITED STATES OF AMERICA.
C-H bond activation is the first step in manufacturing chemical products from readily available light alkane feedstock and typically proceeds via carbon-intensive thermal processes. The ongoing emphasis on decarbonization via electrification motivates low-temperature electrochemical alternatives that could lead to sustainable chemicals production. Platinum (Pt) electrocatalysts have shown activity towards reacting alkanes; however, little is known about propane electrocatalytic activation and conditions suitable for enabling selective oxidation to valuable products.
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December 2024
National Drug Information and Adverse Drug Reactions Monitoring Centre, Hanoi University of Pharmacy, Hanoi, Vietnam.
Objective: Meropenem degradation poses a challenge to continuous infusion (CI) implementation. However, data about the impact of degradation on the probability of target attainment (PTA) of meropenem has been limited. This study evaluated the stability of meropenem brands and the consequence of in-bottle degradation on PTA in different environmental scenarios.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Jilin University, Chemistry, 2699 Qianjin Street, 130012, Changchun, CHINA.
Green ammonia synthesis using fluctuating renewable energy supply in decentralized process is a goal that has been long sought after. Ammonia synthesis with non-thermal plasma under mild conditions is a promising technology, but it faces the critical challenge of low energy efficiency. Herein, we develop an easily-scalable AuCu3/Cu catalyst, which consists of a decimeter-scale metallic Cu antenna and nano-scale AuCu3 catalytic sites on metallic Cu surface, significantly enhancing the energy efficiency and ammonia yield in a radio-frequency (RF) plasma system.
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