No abstract

Highly dispersed Cu@FeCo/rGO catalysts have been prepared by two-step reduction method and used for hydrogen production from ammonia borane (NH3BH3, AB) hydrolysis at 298 K.

The vibration signal measured from the cylinder head contains much effective information about the combustion process. The vibration signal can be measured with a vibration displacement sensor, a vibration velocity sensor or a vibration acceleration sensor. In this study the signals measured with the three sensors were compared. The comparison results showed that the vibration displacement measured from the cylinder head is mainly caused by the fixed bracket of the diesel engine, and it is difficult to extract combustion information from the vibration displacement. The vibration velocity signal was compared with the pressure increase rate. The comparison results showed that the two signals have similar trends in the main combustion process. The vibration velocity signal contains much information about combustion. The vibration acceleration signal is hardly influenced by the fixed bracket but contains the vibration response excited by the impact of the opening and closing of the valves and other impact-exciting sources. Based on the results of analyses, it can be concluded that the vibration velocity sensor is the best sensor to estimate the combustion process. The vibration velocity signal was used to estimate the timing of the start of combustion for a two-cylinder homogeneous charge compression ignition engine. The results demonstrated that the accuracy of estimation fulfils the requirement of the application.

The booming electric vehicle industry continues to place higher requirements on power batteries related to economic-cost, power density and safety. The positive electrode materials play an important role in the energy storage performance of the battery. The nickel-rich NCM (LiNixCoyMnzO2 with x + y + z = 1) materials have received increasing attention due to their high energy density, which can satisfy the demand of commercial-grade power batteries. Prominently, single-crystal nickel-rich electrodes with s unique micron-scale single-crystal structure possess excellent electrochemical and mechanical performance, even when tested at high rates, high cut-off voltages and high temperatures. In this review, we outline in brief the characteristics, problems faced and countermeasures of nickel-rich NCM materials. Then the distinguishing features and main synthesis methods of single-crystal nickel-rich NCM materials are summarized. Some existing issues and modification methods are also discussed in detail, especially the optimization strategies under harsh conditions. Finally, an outlook on the future development of single-crystal nickel-rich materials is provided. This work is expected to provide some reference for research on single-crystal nickel-rich ternary materials with high energy density, high safety levels, long-life, and their contribution to sustainable development.