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31.
The stability of Mott conventional spherically symmetric and retarding-potential conical polarimeters are compared for the case when the position of the electron beam at their inputs is changed. The primary electron energies are 500 and 1600 eV. When the electron beam is shifted by 0.6 mm, the count rate of the former polarimeter remains unchanged, while for the latter, it changes by ≈7 and ≈18% for the energies 1600 and 500 eV, respectively. This instability may cause errors in measuring the degree of polarization of the electron beam. 相似文献
32.
Dmitry D. Zhdanov Vadim G. Sokolov Igor S. Potemin Alexey G. Voloboy Vladimir A. Galaktionov Nikolay Kirilov 《Optical Review》2014,21(5):642-650
The article is devoted to elaboration of the model of scattering polarization film like dual brightness enhancement film (DBEF). This model is used for computer design of backlighting system of liquid crystal display (LCD) where light polarization is important. The model elaboration required development of measurement methods and reconstruction of the parameters for the film polarization, development of the accurate computer model of the polarized light scattering on thin surface. The results of design of LCD backlight with polarization film are presented in the article as well. So it was demonstrated that design of backlight devices with DBEF is possible with help of elaborated software. 相似文献
33.
P. Drescher H. G. Andresen K. Aulenbacher J. Bermuth Th. Dombol H. Fischerz H. Euteneuer N. N. Faleev M. S. Galaktionov D. v. Harrach P. Hartmann J. Hoffmann P. Jennewein K. H. Kaiser S. Köbis O. V. Kovalenkov H. J. Kreide J. Langbeine Y. A. Mamaev Ch. Nachtigall M. Petri S. Plützer E. Reicherte M. Schemies H. -J. Schöpe K. -H. Steffens M. Steigerwald A. V. Subashiev H. Trautner D. A. Vinokurov Y. P. Yashin B. S. Yavich 《Applied Physics A: Materials Science & Processing》1996,63(2):203-206
Strained layer GaAs.95P.05 photo cathodes are presented, which emit electron beams spinpolarized to a degree of P = 75% typically. Quantum yields around QE = 0.4% are observed routinely. The figure of merit P2 × QE = 2.3 × 10–3 is comparable to that of the best strained layer cathodes reported in literature. The optimum wavelength of irradiating light around 830 nm is in convenient reach of Ti:sapphire lasers or diode lasers respectively. The cathodes are produced using MOCVD-techniques. A GaAs.55P.45-GaAs.85P.15 superlattice structure prevents the migration of dislocations from the substrate and bottom layers to the strained overlayer. The surface is protected by an arsenic layer so that no chemical cleaning is necessary before installation into vacuum. The source of polarized electrons attached to the Mainz race track microtron MAMI works with such cathodes now. More than 1000 hours beamtime have been performed successfully. 相似文献
34.
35.
36.
V. A. Galaktionov S. I. Pohozaev 《Computational Mathematics and Mathematical Physics》2008,48(10):1784-1810
Shock waves and blowup arising in third-order nonlinear dispersive equations are studied. The underlying model is the equation in (0.1) $ u_t = (uu_x )_{xx} in\mathbb{R} \times \mathbb{R}_ + . $ It is shown that two basic Riemann problems for Eq. (0.1) with the initial data $ S_ \mp (x) = \mp \operatorname{sgn} x $ exhibit a shock wave (u(x, t) ≡ S ?(x)) and a smooth rarefaction wave (for S +), respectively. Various blowing-up and global similarity solutions to Eq. (0.1) are constructed that demonstrate the fine structure of shock and rarefaction waves. A technique based on eigenfunctions and the nonlinear capacity is developed to prove the blowup of solutions. The analysis of Eq. (0.1) resembles the entropy theory of scalar conservation laws of the form u t + uu x = 0, which was developed by O.A. Oleinik and S.N. Kruzhkov (for equations in x ? ? N ) in the 1950s–1960s. 相似文献
37.
Pablo Álvarez-Caudevilla Jonathan D. Evans Victor A. Galaktionov 《Mediterranean Journal of Mathematics》2013,10(4):1761-1792
Fundamental global similarity solutions of the tenth-order thin film equation $$u_{t} = \nabla . (|u|^{n} \nabla \Delta^{4}u) \,\,\,\, {\rm in} \,\,\,\, \mathbb{R}^{N} \times \mathbb{R}_{+}$$ , where n > 0 are studied. The main approach consists in passing to the limit ${n \rightarrow 0^{+}}$ by using Hermitian non-self-adjoint spectral theory corresponding to the rescaled linear poly-harmonic equation $$u_{t} = \Delta^{5}u \,\,\,\, {\rm in} \,\,\,\, \mathbb{R}^{N} \times \mathbb{R}_{+}$$ . 相似文献
38.
V. A. Galaktionov 《Proceedings of the Steklov Institute of Mathematics》2008,260(1):123-143
The celebrated result by Baras and Goldstein (1984) established that the heat equation with the inverse square potential in
the unit ball B
1 ⊂ ℝ
N
, N ≥ 3, u
t
= Δ
u
+ in B
1 × (0,T), u|∂B
1 = 0, in the supercritical range c > c
Hardy = does not have a solution for any nontrivial L
1 initial data u
0(x) ≥ 0 in B
1 (or for a positive measure u
0). More precisely, it was proved that a regular approximation of a possible solution by a sequence {u
n
(x,t)} of classical solutions corresponding to truncated bounded potentials given by V(x) = ↦ V
n
(x) = min{, n} (n ≥ 1) diverges; i.e., as n → ∞, u
n
(x,t) → + ∞ in B
1 × (0, T). Similar features of “nonexistence via approximation” for semilinear heat PDEs were inherent in related results by Brezis-Friedman
(1983) and Baras-Cohen (1987). The main goal of this paper is to justify that this nonexistence result has wider nature and
remains true without the positivity assumption on data u
0(x) that are assumed to be regular and positive at x = 0. Moreover, nonexistence as the impossibility of regular approximations of solutions is true for a wide class of singular
nonlinear parabolic problems as well as for higher order PDEs including, e.g., u
t
= , and , N > 4.
Dedicated to Professor S.I. Pohozaev on the occasion of his 70th birthday 相似文献
39.
V. A. Galaktionov 《Computational Mathematics and Mathematical Physics》2008,48(10):1823-1856
The third-order nonlinear dispersion PDE, as the key model,
is studied. Two Riemann’s problems for (0.1) with the initial data S
∓(x) = ∓ sgn.x create shock (u(x, t) ≡ S
−(x)) and smooth rarefaction (for the data S
+) waves (see [16]). The concept of “δ-entropy” solutions and others are developed for establishing the existence and uniqueness
for (0.1) by using stable smooth δ-deformations of shock-type solutions. These are analogous to entropy theory for scalar
conservation laws such as u
t
+ uu
x
= 0, which were developed by Oleinik and Kruzhkov (in x ∊ ℝ
N
) in the 1950s–1960s. The Rosenau-Hyman K(2, 2) (compacton) equation
which has a special importance for applications, is studied. Compactons as compactly supported travelling wave solutions
are shown to be δ-entropy. Shock and rarefaction waves are discussed for other NDEs such as
.
This article was submitted by the author in English.
Dedicated to the memory of Professors O.A. Oleinik and S.N. Kruzhkov 相似文献
((0.1)) |
40.