排序方式: 共有23条查询结果,搜索用时 174 毫秒
1.
Piotr Biler 《Reports on Mathematical Physics》2003,52(2):205-225
We study asymptotic properties of solutions to an extension to arbitrary dimensions of the astrophysical model proposed by Chavanis et al. to explain phenomena of gravitational collapse in clouds of self-gravitating particles. In particular, we show that in the two-dimensional case the solutions can be continued to global ones, while in three space dimensions large data of negative energy blow up in a finite time. Relations between isothermal, Streater's energy-transport and the present models are also studied. 相似文献
2.
P. Biler 《Letters in Mathematical Physics》1984,8(1):1-6
We generalize Shucker's result on the asymptotically-classical behaviour of the quantum system with zero potential in Nelson's stochastic interpretation of quantum mechanics to the case of the one-dimensional potential scattering. 相似文献
3.
Kopel Pavel Trávníček Zdeněk Kvítek Libor Biler Martin Pavlíček Marek Šindelář Zdeněk Marek Jaromír 《Transition Metal Chemistry》2001,26(3):282-286
NiII mixed-ligand complexes of compositions [Ni(pmdien)(ttcH)] (1), [Ni(baphen)2(ttcH)] · 4H2O (2), [Ni-(dpa)(ttcH)(H2O)] (3), [Ni(cyclam)(ttcH)] · 2H2O (4), [Ni(hexaa)](ttcH) (5) and [Ni(hexab)(ttcH)] · 2H2O (6), (baphen = 4,7-diphenyl-1,10-phenanthroline, dpa = 2,2-dipyridylamine, cyclam = 1,4,8,11-tetraazacyclotetradecane, hexaa = 1,3,6,9,11,14-hexaazatricyclo[12.2.1.16,9]-octadecane, hexab = 1,8-dimethyl-1,3,6,8,10,13-hexaazacyclotetradecane) have been prepared and characterized by means of i.r., u.v.–vis. spectroscopies and magnetochemical measurements. The redox properties of the complexes were studied by cyclic voltammetry. The crystal and molecular structure of [Ni(pmdien)(ttcH)] was determined. The nickel atom is penta-coordinated by three N atoms of pmdien, and by S and N atoms of trithiocyanurate(2–) anion. 相似文献
4.
Trávníček Zdeněk Walla Jan Kvítek Libor Šindelář Zdeněk Biler Martin 《Transition Metal Chemistry》1999,24(6):633-637
Nickel(II) xanthate complexes of general formula, [Ni(Rxa)2(L)] [R = i-Pr, i-Am, xa = OCS–
2, L = 4,7-diphenyl-1,10-phenanthroline(baphen), 4,4-dimethyl-2,2-bipyridyl (me2bpy), 2-9-dimethyl-1,10-phenanthroline(neo) or trans-1,2-diaminocyclohexane (dch)] and [Ni(Rxa)(cyclam)](Rxa) (= 1,4,8,11-tetraazacyclotetradecane) have been synthesized and characterized by elemental analyses, i.r. and electronic spectroscopy, magnetic and conductivity measurements. The complexes with cyclam were studied by cyclic voltammetry. Values of magnetic moments at room temperature lie within the 3.25–3.51 B.M. range and thus indicate the presence of two unpaired electrons, except for the complexes with cyclam, where the anomalous values of 1.76 and 1.74 B.M. were obtained in respect to the nickel(II) complexes. Magnetic susceptibility data for [Ni(i-Prxa)(cyclam)](i-Prxa) were measured over the 79–298 K range and indicate no exchange interaction between paramagnetic nickel(II) centres. 相似文献
5.
Piotr Biler 《Mathematical Methods in the Applied Sciences》1990,12(2):95-103
Dissipative perturbations of hyperbolic equations such as utt + But + A2u = 0 with positive operators A, B are considered. The rates of decay and partition of energy theorems are established for solutions of these equations. 相似文献
6.
Piotr Biler 《Mathematical Methods in the Applied Sciences》1991,14(6):427-443
We study the asymptotic behaviour in time of the solutions of dissipative perturbations of wave-type equations in ?N, utt + But + Au + G(u) = 0, with commuting positive operators A, B and a power like non-linearity G(u). First we give some (pseudo) conformal invariants of the linear operator in the equation. This allows us to derive optimal decay rates for the solutions of the linearized problems. We then prove some decay estimates for the non-linear problems using the tools of scattering theory and the aforementioned conformal invariants. 相似文献
7.
The existence and nonexistence of global in time solutions is studied for a class of equations generalizing the chemotaxis
model of Keller and Segel. These equations involve Lévy diffusion operators and general potential type nonlinear terms. 相似文献
8.
We show that the supremum norm of solutions with small initial data of the generalized Benjamin-Bona-Mahony equation ut-△ut=(b,▽u)+up(a,▽u)in x?Rn,n≥2, with integer p≥3 , decays to zero like t-2/3 if n=2 and like t-1+6, for any δ0, if n≥3, when t tends to infinity. The proofs of these results are based on an analysis of the linear equation ut-△=(b,▽u)) and the associated oscillatory integral which may have nonisolated stationary points of the phase function. 相似文献
9.
In this paper we study the Cauchy problem for the fractional diffusion equation ut + (?Δ)α/2u=?·(u?(Δ?1u)), generalizing the Keller–Segel model of chemotaxis, for the initial data u0 in critical Besov spaces ?(?2) with r∈[1, ∞], where 1<α<2. Making use of some estimates of the linear dissipative equation in the frame of mixed time–space spaces, the Chemin ‘mono‐norm method,’ Fourier localization technique and the Littlewood–Paley theory, we obtain a local well‐posedness result. We also consider analogous ‘doubly parabolic’ models. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
10.
This note presents an elementary approach to the nonexistence of solutions of a linear initial-boundary value problem for
the heat diffusion equation on a punctured disc. 相似文献