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We report a theoretical study on the valley-filter and valley-valve effects in the monolayer graphene system by using electrostatic potentials, which are assumed to be electrically controllable. Based on a lattice model, we find that a single extremely strong electrostatic-potential barrier, with its strength exceeding the hopping energy of electrons, will significantly block one valley but allow the opposite valley flowing in the system, and this is dependent on the sign of the potential barrier as well as the flowing direction of electrons. In a valley-valve device composed of two independent potential barriers, the valley-valve efficiency can even amount to 100% that the electronic current is entirely prohibited or allowed by reversing the sign of one of potential barriers. The physics origin is attributed to the valley mixing effect in the strong potential barrier region. Our findings provide a simple electric way of controlling the valley transport in the monolayer graphene system.

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The fiber reinforced composites materials possess some excellent characteristics, including light in weight, high strength, high elastic modulus, easy molding and good corrosion resistance and so on. Therefore, fiber reinforced composites materials has extensive application in production-manufacturing of sports equipments, which is valuable to improve player performance. This study elaborated the application advantages of fiber reinforced composites materials in sports equipments, and selection principles, product variety, application example in order to provide a reference for sports equipment manufacturing.