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31.
William D. Banks Asma Harcharras 《Proceedings of the American Mathematical Society》2004,132(7):2121-2125
We show that if the norm of an idempotent Schur multiplier on the Schatten class lies sufficiently close to , then it is necessarily equal to . We also give a simple characterization of those idempotent Schur multipliers on whose norm is .
32.
Qing-xuYan Hui-chaoZou De-xingFeng 《应用数学学报(英文版)》2003,19(2):239-246
In this paper, the stabilization problem of nonuniform Timoshenko beam by some nonlinear boundary feedback controls is considered. By virtue of nonlinear semigroup theory, energy-perturbed approach and exponential multiplier method, it is shown that the vibration of the beam under the proposed control actiondecays exponentially or in negative power of time t as t→∞. 相似文献
33.
Imaginary powers of Laplace operators 总被引:1,自引:0,他引:1
We show that if is a second-order uniformly elliptic operator in divergence form on , then . We also prove that the upper bounds remain true for any operator with the finite speed propagation property.
34.
M. Yu. Doladov V. S. Kazakevich I. G. Kalashnikov V. V. Kupaeva V. A. Shcherbakov 《Journal of Applied Spectroscopy》2001,68(4):708-710
The results of an investigation of the reflection spectrum of the human tympanic membrane in the visible and near IR ranges ( = 400–900 nm) are reported. 相似文献
35.
Consider the stochastic partial differential equationdu
(t,x) = (t)u
(t, x)dt + dW
Q(t,x), 0 t T
where = 2/x
2, and is a class of positive valued functions. We obtain an estimator for the linear multiplier (t) and establish the consistency, rate of convergence and asymptotic normality of this estimator as 0. 相似文献
36.
Q. Md. Alfred T. Chakravarty G. Singh S. K. Sanyal 《International Journal of Infrared and Millimeter Waves》2007,28(10):881-887
In radar, planar phased array antenna plays vital role in electronic scanning in the azimuth and elevation direction to the
horizon. In most operations using planar phased array both the coordinates of azimuth and elevation, are steered electronically.
In this paper a conceptual schematic of a phased array antenna with programmable time delay units has been presented. It is
shown that by suitably exploiting the time delay matrix one can have electronic beam rotation around the target axis as required
in conical scan. Thus both the elevation and azimuth motors in conical scan system are replaced by electronic scanning. Heuristically,
we have selected eight consecutive points for beam rotation in a polygon shape and can also be extended almost circular shape
by increasing number of array elements and phase shifter (delays) in the delay matrix. The array requires dual control of
phase gradient and individual phase values. The whole array is controlled by micro-controller. This presents exciting possibilities
in radar operation. 相似文献
38.
It is shown that the multiplier norm of a shifted Jacobi multiplier sequence can be estimated by the (same) multiplier norm
of the original sequence uniformly with respect to the shift. Muckenhoupt’s transplantation theorem for Jacobi series is used
essentially, for which also a functional analytic understanding is given in terms of the minimality of the Jacobi system in
weighted L
p
-spaces.
相似文献
39.
We use the improved Faddeev-Jackiw quantization method to quantize the electromagnetic field and its Lagrange multiplier fields. The method's comparison with the usual Faddeev-Jackiw method and the Dirac method is given. We show that this method is equivalent to the Dirac method and also retains all the merits of the usual Faddeev-Jackiw method. Moreover, it is simpler than the usual one if one needs to obtain new secondary constraints. Therefore, the improved Faddeev-Jackiw method is essential. Meanwhile, we find the new meaning of the Lagrange multipliers and explain the Faddeev-Jackiw generalized brackets concerning the Lagrange multipliers. 相似文献
40.
Ajit Patel Amiya K. Pani Neela Nataraj 《Numerical Methods for Partial Differential Equations》2008,24(6):1460-1484
In this article a standard mortar finite element method and a mortar element method with Lagrange multiplier are used for spatial discretization of a class of parabolic initial‐boundary value problems. Optimal error estimates in L∞(L2) and L∞(H1)‐norms for semidiscrete methods for both the cases are established. The key feature that we have adopted here is to introduce a modified elliptic projection. In the standard mortar element method, a completely discrete scheme using backward Euler scheme is discussed and optimal error estimates are derived. The results of numerical experiments support the theoretical results obtained in this article. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2008 相似文献