| 1. |
- Chao, Xujiang, et al.
(författare)
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FRACTAL-BASED MODEL FOR EVALUATING THE FILTRATION EFFICIENCY OF THE NON-WOVEN FIBROUS COMPOSITES
- 2022
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Ingår i: Fractals. - : World Scientific Pub Co Pte Ltd. - 0218-348X. ; 30:03
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Tidskriftsartikel (refereegranskat)abstract
- The classic single-fiber efficiency model based on ordered packing of fiber composites has been widely used to predict filtration efficiency of fibrous filters for 40 years. However, the simplified single-fiber model often overestimates the filtration efficiency as most fibrous composite filters are composed of randomly distributed fibers. The numerical methods have been successfully employed to re-construct the realistic fiber composites, but simulation of the multi-mechanism filtration process in the complex fibrous architecture is computationally expensive and case-based and derivation of a compact versatile model for broad applications remain challenging. In this work, a fractal-based homogenization model is developed to predict the filtration efficiency of the fibrous composites, by considering the spatially randomly distributed fibers and the quasi-random distribution of pore size. A comparison with available experimental results collected from references shows that the proposed model is of high accuracy in predicting the filtration of submicron aerosol particles. The calculated results show that the Kuwabara hydrodynamic factor is sensitive to the pore fractal dimension. The filtration efficiency for different particle diameters can be divided into three stages, which increase as the proportion of fibers warped by the fluid decreases. In addition, the total efficiency decreases with the increasing pore fractal dimension in a nonlinear trend. For the given fractal dimension, the filtration efficiency increases with the increase of pore size ratio, indicating that the more uniform the pore size distribution, the higher the efficiency.
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| 2. |
- Long, Chang, et al.
(författare)
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Regulating reconstruction of oxide-derived Cu for electrochemical CO2 reduction toward n-propanol
- 2023
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Ingår i: Science Advances. - 2375-2548. ; 9:43
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Tidskriftsartikel (refereegranskat)abstract
- Oxide-derived copper (OD-Cu) is the most efficient and likely practical electrocatalyst for CO2 reduction toward multicarbon products. However, the inevitable but poorly understood reconstruction from the pristine state to the working state of OD-Cu under strong reduction conditions largely hinders the rational construction of catalysts toward multicarbon products, especially C-3 products like n-propanol. Here, we simulate the reconstruction of CuO and Cu2O into their derived Cu by molecular dynamics, revealing that CuO-derived Cu (CuOD-Cu) intrinsically has a richer population of undercoordinated Cu sites and higher surficial Cu atom density than the counterpart Cu2O-derived Cu (Cu2OD-Cu) because of the vigorous oxygen removal. In situ spectroscopes disclose that the coordination number of CuOD-Cu is considerably lower than that of Cu2OD-Cu, enabling the fast kinetics of CO2 reaction and strengthened binding of *C-2 intermediate(s). Benefiting from the rich undercoordinated Cu sites, CuOD-Cu achieves remarkable n-propanol faradaic efficiency up to similar to 17.9%, whereas the Cu2OD-Cu dominantly generates formate.
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