The Falkner-Skan boundary layer steady flow over a fiat stretching sheet is investigated in this paper. The mathematical model consists of continuity and the momentum equations, while a new model is proposed for MHD F...The Falkner-Skan boundary layer steady flow over a fiat stretching sheet is investigated in this paper. The mathematical model consists of continuity and the momentum equations, while a new model is proposed for MHD Finitely Extensible Nonlinear Elastic Peterlin (FENE-P) fluid. The effects of Hall current with the variation of intensity of non-zero pressure gradient are taken into account. The governing partial differential equations are first transformed to ordinary differential equations using appropriate similarity transformation and then solved by Adomian decomposition method (ADM). The obtained results are validated by generalized collocation method (GCM) and found to be in good agreement. Effects of pertinent parameters are discussed through graphs and tables. Comparison with the existing studies is made as a limiting case of the considered problem at the end.展开更多
In this work,silicon-germanium(SiGe)thin films are epitaxially grown on Ge substrates by ultra-high vacuum chemical vapor deposition and then doped with Mn element by ion-implantation and subsequent rapid thermal anne...In this work,silicon-germanium(SiGe)thin films are epitaxially grown on Ge substrates by ultra-high vacuum chemical vapor deposition and then doped with Mn element by ion-implantation and subsequent rapid thermal annealing(RTA).The characterizations show that the epitaxial SiGe thin films are single-crystalline with uniform tensile strain and then become polycrystalline after the ion implantation and following RTA.The magnetization measurements indicate that the annealed thin films exhibit Mn concentration-dependent ferromagnetism up to 309 K and the X-ray magnetic circular dichroism characterizations reveal the spin and orbital magnetic moments from the substitutional Mn element.To minimize the influence of anomalous Hall effect,magneto-transport measurements at a high magnetic field up to 31 T at 300 K are performed to obtain the hole mobility,which reaches a record-high value of~1230 cm^(2)V^(-1)s^(-1),owing to the crystalline quality and tensile strain-induced energy band modulation of the samples.The first demonstration of Mn-doped SiGe thin films with roomtemperature ferromagnetism and high carrier mobility may pave the way for practical semiconductor spintronic applications.展开更多
This paper concerns with the existence of solutions for the following fractional Kirchhoff problem with critical nonlinearity:where (-△)s is the fractional Laplacian operator with 0 〈 s 〈 1, 2s* = 2N/(N - 2s)...This paper concerns with the existence of solutions for the following fractional Kirchhoff problem with critical nonlinearity:where (-△)s is the fractional Laplacian operator with 0 〈 s 〈 1, 2s* = 2N/(N - 2s), N 〉 2s, p ∈ (1,2s*), θ∈ [1, 2s*/2), h is a nonnegative function and A is a real positive parameter. Using the Ekeland variational principle and the mountain pass theorem, we obtain the existence and multiplicity of solutions for the above problem for suitable parameter A 〉 0. Furthermore, under some appropriate assumptions, our result can be extended to the setting of a class of nonlocal integro-differential equations. The remarkable feature of this paper is the fact that the coefficient of fractional Laplace operator could be zero at zero, which implies that the above Kirchhoff problem is degenerate. Hence our results are new even in the Laplacian case.展开更多
文摘The Falkner-Skan boundary layer steady flow over a fiat stretching sheet is investigated in this paper. The mathematical model consists of continuity and the momentum equations, while a new model is proposed for MHD Finitely Extensible Nonlinear Elastic Peterlin (FENE-P) fluid. The effects of Hall current with the variation of intensity of non-zero pressure gradient are taken into account. The governing partial differential equations are first transformed to ordinary differential equations using appropriate similarity transformation and then solved by Adomian decomposition method (ADM). The obtained results are validated by generalized collocation method (GCM) and found to be in good agreement. Effects of pertinent parameters are discussed through graphs and tables. Comparison with the existing studies is made as a limiting case of the considered problem at the end.
基金supported by the National Key Research and Development Program of China(2017YFB0405702)the National Natural Science Foundation of China(52172272)。
文摘In this work,silicon-germanium(SiGe)thin films are epitaxially grown on Ge substrates by ultra-high vacuum chemical vapor deposition and then doped with Mn element by ion-implantation and subsequent rapid thermal annealing(RTA).The characterizations show that the epitaxial SiGe thin films are single-crystalline with uniform tensile strain and then become polycrystalline after the ion implantation and following RTA.The magnetization measurements indicate that the annealed thin films exhibit Mn concentration-dependent ferromagnetism up to 309 K and the X-ray magnetic circular dichroism characterizations reveal the spin and orbital magnetic moments from the substitutional Mn element.To minimize the influence of anomalous Hall effect,magneto-transport measurements at a high magnetic field up to 31 T at 300 K are performed to obtain the hole mobility,which reaches a record-high value of~1230 cm^(2)V^(-1)s^(-1),owing to the crystalline quality and tensile strain-induced energy band modulation of the samples.The first demonstration of Mn-doped SiGe thin films with roomtemperature ferromagnetism and high carrier mobility may pave the way for practical semiconductor spintronic applications.
基金supported by National Natural Science Foundation of China(Grant Nos.11601515 and 11401574)the Fundamental Research Funds for the Central Universities(Grant No.3122015L014)the Doctoral Research Foundation of Heilongjiang Institute of Technology(Grant No.2013BJ15)
文摘This paper concerns with the existence of solutions for the following fractional Kirchhoff problem with critical nonlinearity:where (-△)s is the fractional Laplacian operator with 0 〈 s 〈 1, 2s* = 2N/(N - 2s), N 〉 2s, p ∈ (1,2s*), θ∈ [1, 2s*/2), h is a nonnegative function and A is a real positive parameter. Using the Ekeland variational principle and the mountain pass theorem, we obtain the existence and multiplicity of solutions for the above problem for suitable parameter A 〉 0. Furthermore, under some appropriate assumptions, our result can be extended to the setting of a class of nonlocal integro-differential equations. The remarkable feature of this paper is the fact that the coefficient of fractional Laplace operator could be zero at zero, which implies that the above Kirchhoff problem is degenerate. Hence our results are new even in the Laplacian case.