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The hydrodynamics at the fishway entrance play an important role in attracting fish into a fishway. Adjusting the entrance angle of the fishway to allow suitable water flow patterns at the entrance is an effective measure that can be used to improve the attraction efficiency. In this study, we analyzed the movement behavior of grass carp (Ctenopharyngodon idella) in a river channel at a fishway entrance with different fishway entrance angles (30°, 45°, and 60°) and different replenishment velocities (0.1 m/s, 0.2 m/s, and 0.3 m/s). The flow velocity was 0.32–0.50 m/s when the fish head deflected into the entrance under different entrance angles for grass carp. As the entrance angle of the fishway increased, the fish energy consumption increased. The range of energy consumption for grass carp increased from 1.26–3.59 × 10−3 J to 3.32–7.33 × 10−3 J when the entrance angle was increased from 30° to 60°. There was a negative correlation between the entrance angle of the fishway and the deflection angle of the tested fish's head. This research presents a reference that combines fish swimming behavior and hydraulics to optimize the design of fishway entrances. [ABSTRACT FROM AUTHOR]

With the development of 5G information technology, higher requirements are imposed on the heat dissipation performance of conventional polymer-based electronic packaging materials. Fabrication of an interconnected graphene nanosheet framework in polymers is an efficient method. However, current methods for the preparation of graphene nanosheet frameworks are typically complex and have low cross-linking densities. Herein, we prepared high-quality graphene nanosheet frameworks with high cross-link density. When the graphene content was merely 9 wt %, the in-plane thermal conductivity of the epoxy composites reached a high 18.8 W m–1 K–1, resulting in a thermal conductivity enhancement of 1034% per 1 wt % graphene loading, which is superior to most conventional graphene network structures used in polymer phonon pathways. This study provides a facile method to produce high cross-link density graphene nanosheet frameworks, which can inspire future development of graphene nanomaterials in the direction of heat dissipation in electronic packaging. [ABSTRACT FROM AUTHOR]

Doping can greatly reduce the lattice thermal conductivity of thermoelectric materials, which is considered as one of the effective ways to improve the thermoelectric properties of thermoelectric materials. First of all, we use the simple and environmentally friendly solution thermal method combined with the tube furnace sintering technology to explore the optimal temperature of sintering Cu2S in the tube furnace. When the sintering temperature reaches 700 °C, we get the thermoelectric value of 0.21. Subsequently, Cu2S thermoelectric materials doped with xmol%Sn (x = 0.5, 1, 3, 5) were prepared and the optimal concentration of Sn was explored. The Sn atom replaces the Cu atom with a smaller radius, greatly reducing the thermal conductivity of the matrix material. In the sample doped with 1%Sn, the total thermal conductivity reaches 0.31 WK−1 m−1, which is 22.5% lower than that of the pure phase sample. In addition, above 623 K, the conductivity of samples doped with 1%Sn is better than that of intrinsic samples, indicating that Sn doping can optimize the conductivity of Cu2S to a certain extent. At 773 K, the ZT of Cu2S + 1 mol%Sn can reach 0.51. 132% higher than undoped Cu2S.This provides a new idea for the preparation and commercial application of Cu–S based thermoelectric materials. [ABSTRACT FROM AUTHOR]

In this article, density functional theory (DFT) was applied to research the structures of γ-Fe2O3 and MFe2O4 (M=Co, Cu, Zn) and to optimize the adsorption models of gases such as CO and NO onto the catalysts. Additionally, the study analyzed the CO oxidation reaction on MFe2O4 (M=Co, Cu, Zn) and the selective catalytic reduction (SCR) reaction of CO + NO in CuFe2O4 and ZnFe2O4. Results showed that CO can effectively adsorb on the reactive substrates, reacting with lattice oxygen to produce CO2 and oxygen vacancies during the CO oxidation process. γ-Fe2O3 (001) required an energy of 0.95 eV to complete the reaction, while CuFe2O4 (100) needed only 0.33 eV, offering better selectivity. In the reaction of CO + NO on CuFe2O4 and ZnFe2O4, NO adsorbed on the surface with double oxygen vacancy to form N2O2 intermediate, then reacted to produce N2 and fill the oxygen vacancy. CuFe2O4 and ZnFe2O4 required energy barriers of 0.68 eV and 0.73 eV, respectively, demonstrating the feasibility of the CO-SCR reaction on the catalyst surface. Further exploration of the reaction in an oxygen-enriched environment found that O2 can inhibit the CO-SCR reaction. The study reveals that MFe2O4 (M=Co, Cu, Zn) catalysts can improve the catalytic activity of the CO oxidation reaction and CO-SCR reaction, with CuFe2O4 exhibiting the best selectivity and catalytic activity. What's more, this study also provides insights for the simultaneous removal of CO and NO. [ABSTRACT FROM AUTHOR]

The catalytic performance of cobalt–chromium spinel NH3-SCR can be enhanced by Mn-doped and Mn–Ti co-doped catalysts; however, there is insufficient understanding of the underlying reaction mechanism. Our work is based on a first-principles computational approach of density functional theory to calculate the optimized configurations of CoAl2O4(100) both before as well as after being Mn-doped and Mn–Ti co-doped. We also simulated the adsorption behavior of gas molecules such as NH3 and NO on the catalyst before and after doping. The optimized configurations and the associated energy distributions for the NH3 dehydrogenation and SCR reactions on Mn0.1Co0.9Al2O4 and Mn0.1Co0.9Ti0.1Al1.9O4 catalysts have undergone a thorough investigation. Our findings demonstrate that the introduction of Mn-doping and Mn–Ti co-doping can enhance the adsorption capacity of gas molecules, such as NH3 and NO, on CoAl2O4 catalysts while significantly reducing the energy barriers for NH3 dehydrogenation and SCR reactions. The performance of Mn–Ti co-doping surpasses that of Mn-doping. Furthermore, we conducted an investigation into the adsorption of H2O and SO2 on the doped catalysts, revealing that Mn–Ti co-doping effectively enhances the water and sulfur resistance properties of the catalysts. Our study is anticipated to serve as a crucial theoretical guide for the development, preparation, and modification of cobalt–aluminum spinel catalysts. [ABSTRACT FROM AUTHOR]