Enhancing the superconducting transition temperature of thin-layer MoS2 via increasing activation volume

Low friction states for thin solid lubricant film of MoS2

“…We consider a thin solid film (MoS 2 coating) under very high pressure loading in a wavy-rough region of R o (in mean-averaged outer radius) with the outer interface or wall being a fixed wavy-rough surface: r = R o + ϵ sin ( kϕ ), where ϵ is the amplitude of the (wavy) roughness, and the wave number: k = 2 π / L a ( L a is the wave length). First, this matter locally can be expressed as (Kwang-Hua, 2016): where τ is the shear stress, and: is a function of temperature with the dimension of the shear rate (for small shear stress τ≪τ 0 , τ 0 /ξ̇ 0 represents the viscosity of the material). In fact, the force balance gives the shear stress at a radius r as (Kwang-Hua, 2016) τ = –( rdp / dz )/2.…”

“…First, this matter locally can be expressed as (Kwang-Hua, 2016): where τ is the shear stress, and: is a function of temperature with the dimension of the shear rate (for small shear stress τ≪τ 0 , τ 0 /ξ̇ 0 represents the viscosity of the material). In fact, the force balance gives the shear stress at a radius r as (Kwang-Hua, 2016) τ = –( rdp / dz )/2. dp / dz is the pressure gradient along the shearing or frictional (or z -axis) direction.…”

“…Introducing the forcing parameter (Kwang-Hua, 2016): then we have ζ̇ = ξ̇ 0 sinh (Π r / R o ). As ζ̇ = dV / dr ( V is the rate of deformation in the longitudinal ( z -)direction), after integration, we obtain: here V s is the rate of deformation over the bounded surfaces or interfaces, which is determined by the boundary condition (Chu, 1995; Kwang-Hua, 2016).…”

“…Introducing the forcing parameter (Kwang-Hua, 2016): then we have ζ̇ = ξ̇ 0 sinh (Π r / R o ). As ζ̇ = dV / dr ( V is the rate of deformation in the longitudinal ( z -)direction), after integration, we obtain: here V s is the rate of deformation over the bounded surfaces or interfaces, which is determined by the boundary condition (Chu, 1995; Kwang-Hua, 2016). With the microscopic boundary condition (Chu, 1995; Kwang-Hua, 2016), we can derive V considering the microscopic wavy-rough interface using the boundary perturbation technique.…”

“…Along the boundary, we have: where n means the normal. Now, on the outer wall or interface (Chu, 1995; Kwang-Hua, 2016), | dV / dn | = |∇ V : …”