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111.
M. Calixto J. Guerrero J. C. S��nchez-Monreal 《Journal of Fourier Analysis and Applications》2011,17(2):240-264
Using Coherent-State (CS) techniques, we prove a sampling theorem for holomorphic functions on the hyperboloid (or its stereographic projection onto the open unit disk $\mathbb{D}_{1}$ ), seen as a homogeneous space of the pseudo-unitary group SU(1,1). We provide a reconstruction formula for bandlimited functions, through a sinc-type kernel, and a discrete Fourier transform from N samples properly chosen. We also study the case of undersampling of band-unlimited functions and the conditions under which a partial reconstruction from N samples is still possible and the accuracy of the approximation, which tends to be exact in the limit N????. 相似文献
112.
Jos�� Luis Romero 《Journal of Fourier Analysis and Applications》2011,17(1):135-174
We prove a result about producing new frames for general spline-type spaces by piecing together portions of known frames. Using spline-type spaces as models for the range of certain integral transforms, we obtain results for time-frequency decompositions and sampling. 相似文献
113.
A. V. Solov��yov 《Journal of Mathematical Sciences》2011,172(6):894-900
The main facts of the geometry of Finslerian 3-spinors are formulated. The close connection between Finslerian 3-spinors and vectors of the 9-dimensional linear Finslerian space is established. The isometry group of this space is described. The procedure of dimensional reduction to 4-dimensional quantities is formulated. The generalized Duffin?CKemmer equation for a Finslerian 3-spinor wave function of a free particle in the momentum representation is obtained. From the viewpoint of a 4-dimensional observer, this 9-dimensional equation splits into the standard Dirac and Klein?CGordon equations. 相似文献
114.
We consider Hermitian and symmetric random band matrices H in
d \geqslant 1{d \geqslant 1} dimensions. The matrix elements H
xy
, indexed by
x,y ? L ì \mathbbZd{x,y \in \Lambda \subset \mathbb{Z}^d}, are independent and their variances satisfy
sxy2:=\mathbbE |Hxy|2 = W-d f((x - y)/W){\sigma_{xy}^2:=\mathbb{E} |{H_{xy}}|^2 = W^{-d} f((x - y)/W)} for some probability density f. We assume that the law of each matrix element H
xy
is symmetric and exhibits subexponential decay. We prove that the time evolution of a quantum particle subject to the Hamiltonian
H is diffusive on time scales t << Wd/3{t\ll W^{d/3}} . We also show that the localization length of the eigenvectors of H is larger than a factor Wd/6{W^{d/6}} times the band width W. All results are uniform in the size |Λ| of the matrix. This extends our recent result (Erdős and Knowles in Commun. Math.
Phys., 2011) to general band matrices. As another consequence of our proof we show that, for a larger class of random matrices satisfying
?xsxy2=1{\sum_x\sigma_{xy}^2=1} for all y, the largest eigenvalue of H is bounded with high probability by 2 + M-2/3 + e{2 + M^{-2/3 + \varepsilon}} for any ${\varepsilon > 0}${\varepsilon > 0}, where M : = 1 / (maxx,ysxy2){M := 1 / (\max_{x,y}\sigma_{xy}^2)} . 相似文献
115.
In this paper we study and present a complete classification of spacelike surfaces with degenerate Gauss map in the Lorentz?CMinkowski space ${\mathbb L^4}$ . 相似文献
116.
In this paper the existence of a class of self-similar solutions of the Einstein–Vlasov system is proved. The initial data
for these solutions are not smooth, with their particle density being supported in a submanifold of codimension one. They
can be thought of as intermediate between smooth solutions of the Einstein–Vlasov system and dust. The motivation for studying
them is to obtain insights into possible violation of weak cosmic censorship by solutions of the Einstein–Vlasov system. By
assuming a suitable form of the unknowns it is shown that the existence question can be reduced to that of the existence of
a certain type of solution of a four-dimensional system of ordinary differential equations depending on two parameters. This
solution starts at a particular point P
0 and converges to a stationary solution P
1 as the independent variable tends to infinity. The existence proof is based on a shooting argument and involves relating
the dynamics of solutions of the four-dimensional system to that of solutions of certain two- and three-dimensional systems
obtained from it by limiting processes. The spacetimes constructed do not constitute a counterexample to cosmic censorship
since they are not asymptotically flat. They should be seen as the first step on a possible path towards constructing solutions
of importance for understanding the issue of the formation of naked singularities in general relativity. 相似文献
117.
We generalise a necessary and sufficient condition given by Cohn for all the zeros of a self-inversive polynomial to be on the unit circle. Our theorem implies some sufficient conditions found by Lakatos, Losonczi and Schinzel. We apply our result to the study of a polynomial family closely related to Ramanujan polynomials, recently introduced by Gun, Murty and Rath, and studied by Murty, Smyth and Wang as well as by Lalín and Rogers. We prove that all polynomials in this family have their zeros on the unit circle, a result conjectured by Lalín and Rogers on computational evidence. 相似文献
118.
119.
��С��������������ѧ����î �� 《核聚变与等离子体物理》2018,38(3):329-333
为提高偏滤器的抗中子辐照能力,兼顾高热承载能力和聚变堆经济性的需要,提出了基于熔盐冷却(MSC)的偏滤器靶板结构设计。它采用FLiNaK作为冷却剂,钨镧合金为热沉材料,钨为第一壁材料。通过数值计算评估了靶板的热负荷承载能力,并完成了偏滤器冷却剂回路设计,优化了偏滤器各模块之间的流量分配。此MSC偏滤器靶板设计可以有效去除10~15MW•m-2热负荷,为适应未来聚变堆偏滤器靶板发展的需要提供了一种设计解决方案。 相似文献
120.