66 research outputs found

    The photo-catalytic activities of MP (M = Ba, Ca, Cu, Sr, Ag; P = PO43-, HPO42-) microparticles

    No full text
    For the good performance of apatite-based materials in the removal of dyes and their environment-friendly advantage, five kinds of apatite microparticles of MP (M = Ba, Ca, Cu, Sr, Ag; P = PO43-, HPO42-) were synthesized by a simple precipitation method and their photo-catalytic properties were invested. Better performance in the decolorization of methyl orange (MO) under the assistance of H2O2 than that of TiO2 were obtained for all the MPs. The photo-catalytic activity was mainly affected by surface area, energy band, impurity, crystallinity and crystal structure. The DFT calculation results demonstrated that the 2p of O and 3p of Pin PO43- played the main role in the photo-catalytic process. This work would be helpful to design and synthesize low cost apatite materials with good photo-catalytic performance. (C) 2013 Elsevier B.V. All rights reserved

    On positive solutions of quasilinear elliptic systems

    Get PDF
    summary:In this paper, we consider the existence and nonexistence of positive solutions of degenerate elliptic systems }Δpu=f(x,u,v),in Ω,Δpv=g(x,u,v),in Ω,u=v=0,on Ω, \left\rbrace \begin{array}{ll}-\Delta _p u = f(x,u,v), &\quad \text{in} \ \Omega , -\Delta _p v = g(x,u,v), &\quad \text{in} \ \Omega , u = v = 0, &\quad \text{on} \ \partial \Omega , \end{array}\right. where Δp-\Delta _p is the pp-Laplace operator, p>1p>1 and Ω\Omega is a C1,αC^{1,\alpha }-domain in Rn\mathbb R^n. We prove an analogue of [7, 16] for the eigenvalue problem with f(x,u,v)=λ1vp1f(x,u,v)=\lambda _1 v^{p-1}, g(x,u,v)=λ2up1 g(x,u,v)=\lambda _2u^{p-1} and obtain a non-existence result of positive solutions for the general systems

    A generalized Fucik type eigenvalue problem for p-Laplacian

    Get PDF
    In this paper we study the generalized Fucik type eigenvalue for the boundary value problem of one dimensional pp-Laplace type differential equations {(φ(u))=ψ(u),T<x<T;u(T)=0,u(T)=0(*) \left\{\begin{array}{lll} - (\varphi( u')) ' = \psi(u), \quad -T< x < T; \\ \quad u(-T)=0, \quad u(T)=0 \\ \end{array} \right.\tag{*} where φ(s)=αs+p1βsp1,ψ(s)=λs+p1μsp1,p>1.\varphi (s) = \alpha s_+^{p-1} -\beta s_-^{p-1}, \psi (s) = \lambda s_+^{p-1} -\mu s_-^{p-1}, p >1. We obtain a explicit characterization of Fucik spectrum (α,β,λ,μ),(\alpha, \beta, \lambda, \mu), i.e., for which the (*) has a nontrivial solution

    Some surprising results on one-dimensional elliptic boundary value blow-up problem

    No full text
    In this paper we consider the one-dimensional elliptic boundary blow-up problem ∆p(u) = f(u), a < x < b, u(a) = u(b) = + ∞. We show that the structure of the solutions can be very rich even for a simple function f, which indicates that a similar results might hold also in higher dimensional spaces

    Multiple solutions for prescribed boundary value problem

    No full text
    We, in this paper, consider the semilinear elliptic boundary value problem - ∆u = f(x, u) in Ω and u = g on ∂Ω and the corresponding Bolza problem x'' + ∂V(t, x) =0, x(0)= x0, x(T)= x1, where Ω is a bounded open subset in R^n with C² boundary and g is a given continuous function on the boundary of Ω; and T is the given traveling time, x0,x1 are two fixed points in the state space Rn. Under certain conditions on f and V, we show that the above problems have infinitely many solution

    Bifurcation of positive solutions for a semilinear equation with critical Sobolev exponent

    No full text
    In this note we consider bifurcation of positive solutions to the semilinear elliptic boundary-value problem with critical Sobolev exponent displaylinesDeltau=lambdaualphaup+u21,quadu>0,quadhboxinOmega,cru=0,quadhboxonpartialOmega.displaylines{ -Delta u = lambda u - alpha u^p+ u^{2^*-1}, quad u >0 , quad hbox{in } Omega,cr u=0, quad hbox{on } partialOmega. } where OmegasubsetmathbbRnOmega subset mathbb{R}^n, nge3nge 3 is a bounded C2C^2-domain lambda>lambda1lambda>lambda_1, 1010 is a bifurcation parameter. Brezis and Nirenberg [2] showed that a lower order (non-negative) perturbation can contribute to regain the compactness and whence yields existence of solutions. We study the equation with an indefinite perturbation and prove a bifurcation result of two solutions for this equation

    Hölder Continuity of the Inverse ofp-Laplacian

    No full text
    AbstractIn this note, we study the inverse operator (−Δp)−1ofp-Lapalcian on a bounded domain Ω⊂Rn. We show that (−Δp)−1:W−1,p′(Ω)→W1,p0(Ω) is Hölder continuous and is a compact operator fromV(q,s)toW1,p0(Ω),s∈(0,p′),q>p∗ the conjugate of critical Sobolev exponent. As an application, we study existence of positive solutions of two nonlinear elliptic equations

    Boundary blow-up insemilinear elliptic problems with singular weights at the boundary [Elektronisk resurs]

    No full text
    In this paper, we study under what conditions on m(x) and f(u) the problem Δu=m(x)f(u) has a solution in a bounded domain D, which tends to infinity, as x tends to the boundary. We show that if m(x) is singular at the boundary of D, except that the Keller-Osserman condition must hold, the growth of f at the infinity has to be slow for a solution to exist. Some existence results have been established.</p
    corecore