Controllable n-type doping on CVD-grown single- and double-layer graphene mixture.

n-Type doping of mixed single- and double-layer graphene grown by chemical vapor deposition (CVD) using decamethyl-cobaltocene reveals a local-quasilinear relationship between the work function and the logarithm of the dopant solution concentration. The relationship that arises from bandgap opening is deduced by comparing the relationship between the two factors for single- or double-layer graphene. This work has extensive applicability and practical significance in doping CVD-grown graphene.

The spreading frontiers of avian-human influenza described by the free boundary.

In this paper, a reaction-diffusion system is proposed to investigate avian-human influenza. Two free boundaries are introduced to describe the spreading frontiers of the avian influenza. The basic reproduction numbers r 0 F (t) and R 0 F (t) are defined for the bird with the avian influenza and for the human with the mutant avian influenza of the free boundary problem, respectively. Properties of these two time-dependent basic reproduction numbers are obtained. Sufficient conditions both for spreading and for vanishing of the avian influenza are given. It is shown that if r 0 F (0) < 1 and the initial number of the infected birds is small, the avian influenza vanishes in the bird world. Furthermore, if r 0 F (0) < 1 and R 0 F (0) < 1, the avian influenza vanishes in the bird and human worlds. In the case that r 0 F (0) < 1 and R 0 F (0) > 1, spreading of the mutant avian influenza in the human world is possible. It is also shown that if r 0 F (t 0) ⩾ 1 for any t 0 ⩾ 0, the avian influenza spreads in the bird world.