Hydrophobicity changes of polluted silicone rubber introduced by spatial and dose distribution of plasma jet

The hydrophobicity of polluted silicone rubber was improved rapidly under plasma jet treatment.It is an important phenomenon of the interaction between the plasma jet and the porous surface,and shows a wide application prospect in the power system.In this process,the spatial characteristics and dose of plasma jet are very important.Therefore,the variation of hydrophobicity of polluted silicone rubber under plasma jet treatment was studied,and the spatial characteristics and dose of plasma jet on polluted silicone rubber were also investigated in the work.The results show that the surface property(hydrophilic or hydrophobic)depended on the dose of plasma applied to the surface.The effective treated area was a circle,and the contact angles changed along the radial direction of the circle.This was attributable to the diffusion of plasma bullets on the surface and the distribution of plasma species.The plasma dose could be characterized by the energy density of the plasma applied on the surface.With the increase of plasma dose,the surface contact angles first increased rapidly and then decreased gradually.

Existence of Nonnegative Solutions for a Class of Systems Involving Fractional (p, q)-Laplacian Operators

The authors study the following Dirichlet problem of a system involving fractional(p, q)-Laplacian operators:{(-△)_p^su=λa(x)|u|+^(p-2)u+λb(x)|u|^(α-2)|u|~βu+μ(x)/αδ|u|^(γ-2)|v|~δu in Ω,(-△)_p^su=λc(x)|v|+^(q-2)v+λb(x)|u|~α|u|^(β-2)v+μ(x)/βγ|u|~γ|v|^(δ-2)v in Ω,u=v=0 on R^N\Ω where λ > 0 is a real parameter, ? is a bounded domain in RN, with boundary ?? Lipschitz continuous, s ∈(0, 1), 1 < p ≤ q < ∞, sq < N, while(-?)s pu is the fractional p-Laplacian operator of u and, similarly,(-?)s qv is the fractional q-Laplacian operator of v. Since possibly p = q, the classical definitions of the Nehari manifold for systems and of the Fibering mapping are not suitable. In this paper, the authors modify these definitions to solve the Dirichlet problem above. Then, by virtue of the properties of the first eigenvalueλ_1 for a related system, they prove that there exists a positive solution for the problem when λ < λ_1 by the modified definitions. Moreover, the authors obtain the bifurcation property when λ→λ_1^-. Finally, thanks to the Picone identity, a nonexistence result is also obtained when λ≥λ_1.

Structure and tribocorrosion behavior of CrMoSiCN nanocomposite coating with low C content in artificial seawater

CrMoSiCN nanocomposite coatings with a low C content were prepared on Ti−6Al−4V using an unbalanced magnetron sputtering system,and their corresponding microstructures,mechanical properties,and tribocorrosion performance were evaluated in detail.The results revealed that the CrMoSiCN coating had a compact nanocomposite microstructure consisting of CrN and Mo2N nanocrystallites,(Cr,Mo)N solid solution,and Si−C−N amorphous phases.Moreover,the coating exhibited superior mechanical properties with a hardness of 28.6 GPa and an elastic modulus of 273 GPa,owing to the solid solution strengthening effect.The tribocorrosion test results showed that the dominant failure of the Ti−6Al−4V alloy was caused by the corrosion contribution to wear behaviors(synergistic effect).The CrMoSiCN nanocomposite coating could effectively alleviate the material loss caused by the synergistic effect of corrosion and wear behaviors,leading to pure wear behaviors during the entire tribocorrosion process.The corresponding tribocorrosion mechanisms under the open circuit potential and dynamic polarization conditions were discussed in terms of their tribocorrosion behaviors.

Interaction between plasma jet and silicone rubber covered by porous inorganic contaminants:Surface hydrophobicity or hydrophilicity?

The variation of surface hydrophobicity of silicone rubber materials covered with porous inorganic pollution layer under the action of atmospheric pressure plasma jet presents some new features,which have important engineering applications in the field of outdoor insulation of power systems.Interaction of the plasma with the polluted silicone rubber is studied and surface hydrophobicity is measured.Experimental results show that the exposure of plasma greatly accelerates the transfer of low molecular weight siloxanes(LMWs)in the pollution layer.However,the surface hydrophobicity is determined by the LMWs contents and the exposure time.Two acceleration effects of plasma during and after plasma exposure are proposed,their influence on surface hydrophobicity is analysed and related mechanisms are clarified.In addition,the competing influence of plasmainduced acceleration of the transfer of LMWs towards the surface and plasmaoxidation of LMWs on surface hydrophobicity is discussed.