Copper matrix composites containing different volume fractions of B4C particles (0–15%) were first fabricated by spark plasma sintering followed by hot rolling in atmospheric environments, then their microstructures, phase compositions, mechanical properties and sintering mechanism were investigated. It was found that B4C particles distributed relatively homogeneously in the copper matrix. Reaction products of CuC8 and B were observed and identified in the composite. Under increasing B4C particle content, the ultimate tensile, yield strength and elongation to fracture of the composites decreased. Failure mode of composites included: (1) the interfacial debonding and (2) the cleavage fracture of copper. Moreover, micro-discharge between the adjacent particles occurred, and its led to local high temperature at the interface.
PID controller plays an important role in Automatic Train Operation systems. Many researches have been done on the PID parameters estimation. However, the traditional models simplified the characteristics of the trains in different speeds and operation modes. It was difficult to overcome the problems with different kinds of algorithms based on the traditional models, especially the accuracy requirement of the stopping distance. In this paper, a new model of the PID controller was proposed based on the practical train operation stages. And the different response time delay was considered besides of the transmission time delay. With this new model, an Improved Fruit Fly Optimization Algorithm was applied. The tracking performance were greatly improved both on running distance and real time. The simulation results showed a better performance than the traditional methods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.