RESUMEN
Despite the fact that the outstanding properties of graphene are well known, the electrical performance of the material is limited by the contact resistance at the metal-graphene interface. In this study, we demonstrate the formation of "edge-contacted" graphene through the use of a controlled plasma processing technique that generates a bond between the graphene edge and the contact metal. This technique controls the edge structure of the bond and significantly reduces the contact resistance. This simple approach requires no additional post-processing and has been proven to be very effective. In addition, controlled pre-plasma processing was applied in order to produce CVD-graphene field effect transistors with an enhanced adhesion and improved carrier mobility. The contact resistance attained by using pre-plasma processing was 270 Ω µm, which is a decrease of 77%.
RESUMEN
In an effort to define and characterize the initial mineralization product of fracture-healing, we studied the mineral components within a model of endochondral osseous repair. Fracture calluses from the tibiae of rats and rabbits undergoing endochondral fracture-healing were analyzed, in toto and following density fractionation, by physicochemical and crystallographic techniques. Significant changes in mineral composition, crystal size, and density occurred in the early phases of fracture repair. In the rat, two weeks after fracture, the calcium-to-phosphorus ratio was higher than that of the mineral component, possibly due to calcium-binding to some of the macromolecules known to be present. The earliest mineral was poorly crystallized hydroxyapatite with a high carbonate content. Crystal perfection improved rapidly and approached that of normal diaphyseal bone within eight weeks after endochondral fracture in both the rabbit and the rat.