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Abstract: Semiconductor laser with optical feedback emitting chaotic optical signal can be treated as chaotic carrier transmitter. Based on laser rate equations, we numerically study the effect of external injection light on the bandwidth of chaotic carrier transmitter. Our numerical simulation shows that the bandwidth of the chaotic carrier transmitter can be enhanced significantly by external photons injection. Compared with the 2GHz relaxation oscillation frequency of a solitary laser diode without optical injection, the bandwidth of a chaotic carrier transmitter is expanded to 14.5GHz with injection parameter at k inj =0.39. Simulation results also demonstrate that the enhanced bandwidth depends obviously on the frequency detuning between the external injection laser diode and the chaotic carrier transmitter. The maximum bandwidth of the chaotic transmitter can be obtained when the frequency of the injected light is higher than the central frequency of the carrier transmitter between 2GHz and 4GHz. [Copyright &y& Elsevier]

Developing facile and scalable method to prepare oxygen evolution reaction (OER) catalysts which is suitable for industrial water electrolysis at large operating current densities is vital for green hydrogen production, but still remains a great challenge. Herein, we developed a one-step method to in situ fabricate S-doped NiFe oxyhydroxide (S–Ni(Fe)OOH) ultrathin nanosheet on Ni foam at room temperature, which is suitable for scaled up production, by which a electrode with 500 cm2 can be facilely prepared. The prepared S–Ni(Fe)OOH shows excellent OER stability and activity in 5 M KOH, alkaline sewage and seawater, which only need 198, 275 and 284 mV to reach 500 mA cm−2, respectively. Theoretical calculations indicated that the incorporation of S modulates the chemisorption of oxygen-containing intermediates and facilitates the evolution from ∗OH to ∗O, thus enhance the intrinsic OER activity of S–Ni(Fe)OOH. The electrolyzer based on S–Ni(Fe)OOH can reach a current density of 100 mA cm−2 at a small cell voltage of 1.56 V in 1 M KOH, much smaller than the benchmark catalyst Pt/C||IrO 2 (1.87 V). This work provides a facile method to prepare highly efficient catalyst for alkaline sewage and seawater oxidation, which could provide references to the development of catalyst for practical hydrogen production. The S-doped NiFe oxyhydroxide (S–Ni(Fe)OOH) ultrathin nanosheet was in situ fabricate on Ni foam by one step without heating process, which is suitable for scaled up production. The incorporation of S modulates the chemisorption of oxygen-containing intermediates and enhance the intrinsic OER activity of S–Ni(Fe)OOH. [Display omitted] • S-doped NiFe oxyhydroxide (S–Ni(Fe)OOH) was prepared by a facile and scalable method. • The incorporation of S enhance the intrinsic OER activity of S–Ni(Fe)OOH. • S–Ni(Fe)OOH only needs 193 mV to reach 10 mA cm−2 in 1 M KOH. • S–Ni(Fe)OOH displays high OER activity and stability in 5 M KOH solution, alkaline seawater and sewage. [ABSTRACT FROM AUTHOR]

Currently, the sulfate method used for roasting lepidolite to extract lithium presents several issues, including high energy consumption and low recovery efficiency. To address these limitations, we have employed microwave external fields to enhance lithium extraction and modified the roasting process. Microwave-enhanced roasting reduces heating time from 43 to 20 min, significantly lowering energy consumption compared to conventional roasting. Experimental results reveal that the optimal conditions are ferrous sulfate: potassium sulfate: calcium oxide: ore = 2:0.6:0.1:1, roasting temperature at 775 °C, and roasting time of 2 h, resulting in a lithium leaching efficiency of 95.9%. The study of dielectric properties shows that the addition of sulfate improves the microwave absorption characteristics of lepidolite, facilitating rapid heating in the microwave field. Additionally, uniform microwave heating reduces sample melting and adhesion, leading to looser clinker and improved lithium leaching efficiency. The microwave-enhanced sulfate roasting technology holds significant importance for the study of lithium extraction from lepidolite. We have employed microwave external fields to enhance lithium extraction and modified the roasting process. Microwave-enhanced roasting reduces heating time from 43 to 20 min, significantly lowering energy consumption compared to conventional roasting. Additionally, uniform microwave heating reduces sample melting and adhesion, leading to looser clinker and improved lithium leaching efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]

Copper-cadmium slag, produced during the hydrometallurgical process of zinc, is considered as hazardous solid waste. However, a large number of valuable metals (zinc, cadmium, copper and magnesium) are contained in copper-cadmium slag. It is necessary to treat copper-cadmium slag to make it harmless and recycled with an efficient mean. In response to the problems of low oxidation and multiple inclusions hindering leaching reaction, a more effective and ecologically friendly method based on ultrasonic cavitation and mechanical effect is suggested for recovering valuable metals from copper-cadmium slag. The influencing factors of leaching experiment include reaction time, leaching temperature, liquid-solid ratio, sulfuric acid concentration and ultrasound power. The leaching rates of zinc, cadmium, copper and magnesium reached over 97% at 300 W of ultrasonic power, which are much better than that of conventional condition. In addition, ultrasonic assistance shortened the leaching time to 2 h, improving the leaching rate and reducing the extra energy consumption during conventional leaching in the metal recovery process. The particle size of copper-cadmium slag is reduced from 30 μm to 1 μm by virtue of the ultrasonic microjet and microbubble effects. Moreover, the mineralogy analysis results indicate that microstructures and composition of solid slag changed greatly after ultrasonic treatment. The kinetic analysis results show that the activation energy decreases from 34.68 kJ/mol to 6.21 kJ/mol after ultrasound, demonstrating that ultrasonic field can reduce the activation energy and accelerate the reaction rate. As a result, ultrasound-assisted method is shown to be considerably powerful in improving the leaching and recovery efficiency of solid waste slag. [Display omitted] • An ultrasound-assisted measure was proposed to high-efficiently recover copper-cadmium slag. • Reaction mechanism is attributed to the cavitation and mechanical effects of ultrasound. • The leaching rate of copper is over 97% under the optimal conditions. • Ultrasound-assisted can enhance recovery rate visibly compared with traditional metallurgy. [ABSTRACT FROM AUTHOR]