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21.
V.I. Vasyuchka V.A. Moiseienko A.N. Slavin 《Journal of magnetism and magnetic materials》2009,321(20):3498-3501
A correlation receiver capable of receiving pulsed microwave signals having amplitudes substantially below the noise level is proposed and experimentally realized. The device is based on the parametric interaction of two contra-propagating spin waves excited by the received microwave signal and the reference pulsed signal, containing information about the received signal shape, in a ferrite film waveguide. The output nonlinear correlation signal having the doubled carrier frequency and the signal-to-noise ratio enhanced by several orders of magnitude is received by a dielectric resonator coupled to an output microwave transmission line. 相似文献
22.
Mircea Grigoriu 《Journal of computational physics》2010,229(22):8406-8429
Mathematical requirements that the random coefficients of stochastic elliptical partial differential equations must satisfy such that they have unique solutions have been studied extensively. Yet, additional constraints that these coefficients must satisfy to provide realistic representations for physical quantities, referred to as physical requirements, have not been examined systematically. 相似文献
23.
24.
Let be an ideal in a Noetherian local ring . Then the sequence is -regular if every is a non-zerodivisor in and if for all integers , where runs over the elements of the set .
25.
Eugeniusz Zieniuk Agnieszka Boltuc 《International Journal of Solids and Structures》2006,43(25-26):7939-7958
The paper presents a non-element method of solving boundary problems defined on polygonal domains modeled by corner points. To solve these problems a parametric integral equation system (PIES) is used. The system is characterized by a separation of the approximation of boundary geometry from the approximation of boundary functions. This feature makes it possible to effectively investigate the convergence of the obtained solutions with no need of performing the approximation of boundary geometry. The testing examples included confirm high accuracy of the solutions. 相似文献
26.
This paper concentrates on a shortest path problem on a network where arc lengths (costs) are not deterministic numbers, but imprecise ones. Here, costs of the shortest path problem are fuzzy intervals with increasing membership functions, whereas the membership function of the total cost of the shortest path is a fuzzy interval with a decreasing linear membership function. By the max–min criterion suggested in [R.E. Bellman, L.A. Zade, Decision-making in a fuzzy environment, Management Science 17B (1970) 141–164], the fuzzy shortest path problem can be treated as a mixed integer nonlinear programming problem. We show that this problem can be simplified into a bi-level programming problem that is very solvable. Here, we propose an efficient algorithm, based on the parametric shortest path problem for solving the bi-level programming problem. An illustrative example is given to demonstrate our proposed algorithm. 相似文献
27.
以自启动被动锁模掺镱光纤堆积脉冲激光器为种子源,采用非共线相位匹配的方法,进行了光参量啁啾脉冲放大器的实验研究,得到了两级放大总增益为1.1×107,单脉冲能量为11 mJ,能量稳定性小于2% rms,8 nm的放大谱宽.实验结果表明,采用这种结构的光参量啁啾脉冲放大器,放大增益高,系统稳定、结构紧凑、便于调节,同时通过调节种子源中的堆积器,可以得到不同宽度的放大信号脉冲. 相似文献
28.
The effect of fluctuations in the two-variable discrete delay model proposed earlier by us [1] for the circadian rhythm of
the fungal species Neurospora Crassa is studied. We have investigated the effect of parametric and additive noise in two different regimes namely, steady-state
and Period-1 regimes. It is found that under the influence of noise coherent oscillations are generated in the steady-state.
Oscillations are preserved and robust to a wide range of noise intensity in the Period-1 regime. The oscillations in both
these regimes are always found to be close to the circadian period (21.5 h). Coherence resonance is observed when parametric
or velocity additive noise is added near the Hopf bifurcation. Finally, the implications of fluctuations in circadian rhythms
are discussed.
This article is dedicated to Professor Karl Jug on the occassion of his sixtyfifth birthday. 相似文献
29.
Infinite-dimensional parameter-dependent optimization problems of the form ‘minJ(u;p) subject to g(u)?0’ are studied, where u is sought in an L∞ function space, J is a quadratic objective functional, and g represents pointwise linear constraints. This setting covers in particular control constrained optimal control problems. Sensitivities with respect to the parameter p of both, optimal solutions of the original problem, and of its approximation by the classical primal-dual interior point approach are considered. The convergence of the latter to the former is shown as the homotopy parameter μ goes to zero, and error bounds in various Lq norms are derived. Several numerical examples illustrate the results. 相似文献
30.
Jinyu Sun 《Optics Communications》2011,284(19):4745-4748
Noncollinear optical parametric up-conversion generation and amplification are realized in a thick β-barium borate (BBO) crystal, and a couple of visible femtosecond up-conversion laser pulses can be achieved by a femtosecond pulse at 800 nm as the pump sources. The theoretical and experimental results indicate that there exist phase-matching conditions for dual-color noncollinear parametric up-conversion generation and amplification, and their wavelengths can be tuned by rotating the BBO crystal. This parametric up-conversion generation and amplification can be attributed to three and five-wave mixing in a thick BBO crystal, and it shows the potential application on optical parametric chirped pulse amplification (OPCPA) to generate multi-color ultraviolet or visible femtosecond laser pulses pumped directly by femtosecond fundamental laser pulses without frequency-doubling or tripling. 相似文献