Results 261 to 270 of about 3,081,381 (296)

Positive Solutions for Singular Initial Value Problems with Sign Changing Nonlinearities Depending on y′

SUT Journal of Mathematics, 2007
The authors consider the singular initial value problem \[ y''(t)= \Phi(t)f(t,y,y'), \quad t\in(0,T], \qquad y(0)= y'(0)=0, \tag{1} \] where \(f(t,y,y')\) changes sign and may be singular at \(y=0\) and \(y'=0\) and \(f(t,y,y')\) may be superlinear at \(y=+\infty\).
Zhang, Lili, Yan, Baoqiang
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Barrier strips and positive solutions of first order singular and regular initial value problems

Differential Equations, 2009
The present paper deals with the existence of global solutions of first-order regular and singular initial value problems. Using the barrier strip method the authors give sufficient conditions even in the case when the right-hand side has a singularity at the initial value.
Agarwal, R. P., Kelevedjiev, P. S., O'Regan, D.   +2 more
openaire   +1 more source

Multiple positive solutions of non-local initial value problems for first order differential systems

Nonlinear Analysis: Theory, Methods & Applications, 2012
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Precup, Radu, Trif, Damian
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Radiation-hygienic support of work with nitride fuel for fast reactors: problems, achievements and prospects. Initial position

Russian Journal of Occupational Health and Industrial Ecology, 2021
The article is devoted to the substantiation of the need to implement a special program of radiation-hygienic support of work with nitride fuel for fast neutron reactors. It is shown that at the current pace of implementation of the project direction "Breakthrough", in conditions when achievements in scientific research lead to a revision of design and
Marina R. Popchenko, Alexander G. Tsovyanov, Sergei M. Shinkarev, Anatoly V. Simakov, Vladimir N. Klochkov, Igor P. Korenkov   +5 more
openaire   +1 more source

Existence of Positive Solutions to the Singular Initial Value Problems of Fractional Differential Equations

Advanced Materials Research, 2011
In this paper, we consider the existence of positive solutions for the initial value problem of nonlinear fractional differential equations where and is the Riemann–Liouville fractional derivative. By using the Nonlinear Alternative of Leray and Schauder theorem, some sufficient conditions for the existence of at least one positive solution for the ...
Qiu Ping Li, Shu Rong Sun, Zhen Lai Han, Yi Ge Zhao   +3 more
openaire   +1 more source

Positive solutions of a nonlinear initial-value problem on half-line

Journal of Optimization Theory and Applications, 1983
The nonlinear initial-value problemu″(t)+f(t,u(t))=0,u(t0)+bu′(t0)=c,t0≥0,b≤0,c≥0, is considered for positive solutions on [t0, ∞). Existence of positive solutions is proved without the hypothesis thatf(t, ω)≥0 (or ≤0), using the lattice fixed point theorem.
openaire   +1 more source

Blow-up in a semilinear parabolic problem with variable source under positive initial energy

Applicable Analysis, 2014
In this paper, we consider a class of semilinear parabolic equations with variable source under homogeneous Dirichlet boundary conditions in a bounded domain with smooth boundary and For all we prove that the classical solutions to the above equation blow-up in finite time with arbitrary positive initial energy and suitable large initial values.
Ali Khelghati, Khadijeh Baghaei
openaire   +1 more source

Optimal control of positive solution to initial value problem for fractional integro-differential equations

2017 29th Chinese Control And Decision Conference (CCDC), 2017
In this paper, we consider the existence and uniqueness of positive solutions to fractional integro-differential equations by using mixed monotone operator. On this basis, we investigate the control problem of positive solutions to our equation and obtain the existence condition of an optimal control that minimizes the nonlinear cost functional.
Yongjie Zhang, Lingling Zhang
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On the free boundaries in a nonlinear diffusion-convection problem with positive initial conditions

Nonlinear Analysis: Theory, Methods & Applications, 1991
The paper is concerned with the behavior for large \(x (x\geq x_ 1)\) of weak solutions of equations of the form \(u_ t=(u^ m)_{xx}+b(x)(u^ n)_ x\) in \(\{(x,t)\mid x\in\mathbb{R}, t>0\}\) which satisfy \(u(x,0)=u_ 0(x)\) for \(x\in\mathbb{R}\). Here, \(00\) for \(x\in\mathbb{R}\), \(u_ 0\in C^ 0(\mathbb{R})\), \(u_ 0(x)>0\) for \(x\in\mathbb{R ...
Kersner, Robert, Nicolosi, Francesco
openaire   +1 more source

Existence and uniqueness of positive solutions to sublinear-linear initial value problems

Acta Mathematica Sinica, 1994
This nice paper is concerned with the following sublinear-linear initial value problem: (1) \(x' = a(t)x + \sum^ n_{i = 1} b_ i(t)x^{r_ i} + c(t)\) for \(t>0\), (2) \(x(0)=0\), where \(a,b_ i\) \((i=1,2, \dots,n)\) and \(c\) are integrable and \(r_ 1,r_ 2,\dots,r_ n\) are reals such that ...
openaire   +2 more sources