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Abstract ZnO/HfO2:Eu nanocables were prepared by radio frequency sputtering with electrospun ZnO nanofibers as cores. The well-crystallized ZnO/HfO2:Eu nanocables showed a uniform intact core–shell structure, which consisted of a hexagonal ZnO core and a monoclinic HfO2 shell. The photoluminescence properties of the samples were characterized. A white-light band emission consisted of blue, green, and red emissions was observed in the nanocables. The blue and green emissions can be attributed to the zinc vacancy and oxygen vacancy defects in ZnO/HfO2:Eu nanocables, and the yellow–red emissions are derived from the inner 4f-shell transitions of corresponding Eu3+ ions in HfO2:Eu shells. Enhanced white-light emission was observed in the nanocables. The enhancement of the emission is ascribed to the structural changes after coaxial synthesis.

Developing high‐performance platinum (Pt) single atom catalyst with maximum metal‐atom‐utilization efficiency is of significance for water electrolysis, which demonstrates enormous potentials toward hydrogen evolution reaction (HER). In addition to stably immobilizing Pt single atoms on a support material, it is highly desired to elaborately tailor their coordination environments for achieving optimized HER performance. In this work, a general strategy is reported to develop advanced catalysts with Pt single atoms immobilized on conjugated polymers, where their coordination environments and HER activities can be readily tailored by adjusting the cation‐π interactions formed between the Pt single atoms and conjugated polymers. For the proof‐of‐concept study, polypyrrole (PPy), polyfuran (PFu), and polythiophene (PTh) with analogous molecular structures are investigated, where the N, O, and S heteroatoms in PPy, PFu, and PTh can affect their π domains and induce different cation‐π interactions. Experimental and theoretical studies both suggest that the HER performance of the resulting catalysts follows the trend of Pt1‐PTh < Pt1‐PFu < Pt1‐PPy, which shows a correlation with their cation‐π interactions. Moreover, by utilizing the microstructure‐tailorable property of conjugated polymers, PPy aerogel with enhanced specific surface area are prepared to support Pt single atoms, achieving substantial HER performance improvement. [ABSTRACT FROM AUTHOR]

In this study, several 3-dimensional (3-D) parameter estimation and localization algorithms for wireless near-field (NF) sources are proposed employing the uniform circular array (UCA) structure. In the single-base-station case, the algebraic relation is demonstrated between the azimuth angle under the far-field (FF) assumption and the actual NF source firstly. Secondly, two groups of antenna pairs are selected with distances less than half the wavelength, which are called short baselines in the interferometer method. The foregoing short-baseline method is qualified to localize an NF source. In addition, a long-baseline method is also proposed with further research. Two groups of antenna pairs with distances greater than half the wavelength are selected as two long baselines. In the multiple-base-stations case, another two novel algorithms are also proposed. The first one is the centroid algorithm, which is based on the centroid calculation of three estimated source locations. And the second one is the perpendicular foot algorithm, which takes the perpendicular foot within three estimated source locations as the final positioning location. Simulation results illustrate that the proposed algorithms can achieve higher localization accuracy than the conventional 3-D Root MUSIC method. Moreover, the long-baseline method performs better than the short-baseline method. And it is also shown that the proposed perpendicular foot algorithm shows better performance than the proposed centroid algorithm. [ABSTRACT FROM AUTHOR]

Biomass waste, which is biodegradable and vastly underutilized, is generated in huge quantities worldwide. Forestry and agricultural biomass wastes are notable for their wide availability, high yield, biodegradability, and recyclability. The accumulation of these wastes not only occupies valuable land but causes serious environmental pollution, which can ultimately harm human health. Therefore, leveraging scientific technology to convert forestry and agricultural bio-waste into bioenergy and other valuable products is crucial. In this paper, common forestry and agricultural bio-waste such as straw, rice husks, livestock manure, tree branches, sawdust, and bioenergy (bioethanol, biogas, biodiesel, biohydrogen) were selected as keywords, with the theme of green and efficient utilization. This paper provides a comprehensive review of the sources of biomass waste, existing recycling technologies, and the potential of forestry and agricultural bio-waste as material additives and for conversion to biomass energy and other derivatives, along with future recycling prospects. [ABSTRACT FROM AUTHOR]