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81.
The effects of the compensation ratio with dispersion post-compensation on nonlinear single channel and WDM systems with 10 Gb/s per channel are numerically investigated. When the transmission signal per channel is 10 Gb/s RZ pulse and the amplifier span is 50 km, proper undercompensation can enhance the performance of the nonlinear single channel system and the nonlinear WDM system. But the enhanced distance of the nonlinear WDM system is not as obvious as that of the single channel system, because the cross-phase-modulation effect plays an important role in the nonlinear WDM system. 相似文献
82.
Akhlesh Lakhtakia Werner S. Weiglhofer 《International Journal of Infrared and Millimeter Waves》1998,19(1):95-106
We derive expressions for the source–region electromagnetic field in an affinely transformable Axially Uniaxial Bianisotropic Medium (AUBM) by employing a technique originally developed by Fikioris for free space (i.e., vacuum). The obtained results may be used to determine the scattering response of an electrically small bianisotropic particle embedded in an affinely transformable AUBM. They can therefore be further used to homogenize a wide class of particulate composites. 相似文献
83.
H. Iwasaki T. Motobayashi H. Akiyoshi Y. Ando N. Fukuda H. Fujiwara Zs. Fülöp K. I. Hahn Y. Higurashi M. Hirai I. Hisanaga N. Iwasa T. Kijima A. Mengoni T. Minemura T. Nakamura M. Notani S. Ozawa H. Sagawa H. Sakurai S. Shimoura S. Takeuchi T. Teranishi Y. Yanagisawa M. Ishihara 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):55-58
Experimental studies on in-beam γ-ray spectroscopy using a 12Be radioactive beam are presented. Inelastic scattering of the neutron-rich 12Be nucleus on 208Pb, 12C, and (CH2)n targets has been studied by measuring de-excitation γ-rays in coincidence with scattered particles. The level schemes and
transition probabilities are determined for low-lying excited states in 12Be. The present paper presents a brief review of the spectroscopic results, which may be associated with the N = 8 shell quenching near the drip line.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
84.
Focusing of electromagnetic waves into a uniaxial crystal 总被引:1,自引:0,他引:1
We derive integral representations suitable for studying the focusing of electromagnetic waves through a plane interface into a uniaxial crystal. To that end we start from existing exact solutions for the transmitted fields due to an arbitrary three-dimensional (3D) wave that is incident upon a plane interface separating two uniaxial crystals with arbitrary orientation of the optical axis in each medium. Then we specialize to the case in which the medium of the incident wave is isotropic and derive explicit expressions for the dyadic Green's functions associated with the transmitted fields as well as integral representations suitable for asymptotic analysis and efficient numerical evaluation. Relevant integral representations for focused 3D electromagnetic waves are also given. Next we consider the special case in which (i) the incident field is a two-dimensional (2D) TM wave and (ii) the optical axis in the crystal lies in the plane of incidence, implying that we have a 2D vectorial problem, and derive dyadic Green's functions, integral representations suitable for asymptotic and numerical treatment, and integral representations for focused TM fields. Numerical results for focused 2D TM fields based on these integral representations as well as corresponding experimental results will be presented in forthcoming papers. 相似文献
85.
A. Gedeon 《Applied physics. B, Lasers and optics》1973,2(1):15-22
Efficient focussing of surface acoustic waves has been achieved using a properly shaped gold film deposit on the −22.3° rotated
Y-cut surface of quartz. The acoustic wave field was studied with laser probing techniques. A more than threefold increase
in intensity and a tenfold decrease in beam width was observed at the focal point. The focussing action was obtained with
the elastic wave equivalent of the Fresnel phase-reversal zone plate of optics. The multiple foci of this device allowed a
simultaneous generation of acoustic waves in nearly all directions on the surface. Consequently, the surface wave velocity
anisotropy could be determined completely. The experimental results are in very good agreement with the calculated velocity
anisotropy. Electromagnetic diffraction theory is adopted to the two dimensional anisotropic system to analyse the performance
of the focussing device. 相似文献
86.
D. A. Dement'ev A. L. Ivanov O. B. Serov A. G. Stepanov Yu. A. Matveets S. V. Chekalin A. M. Smolovich 《Optics Communications》1998,150(1-6):38-42
The mechanism of wavefront reconstruction by geometric-optical reflection of reconstruction radiation from surfaces with constant phase differences between the object and reference waves has been investigated. The main difference between this mechanism and a holographic one is the absence of diffraction of the reconstructing radiation by the periodic structure and as a consequence the achromatism of the reconstruction process. Incoherent continuous radiation and ultrashort laser pulses were used in the experiments. The effect of achromatic reconstruction has been obtained after recording the interference of counterpropagating 30–40 fs pulses from an Al2O3:Ti3+ laser in bulk media. 相似文献
87.
田忠玉 《核聚变与等离子体物理》1985,(2)
本文叙述了一个静电堵漏会切型等离子体约束系统。基本设计参数为:电极所在之处磁场达10kG;堵漏电压为10kV;等离子体密度~10~(12)cm。;离子温度>O.5keV;约束时问>5ms。 该装置可用作为等离子体积累与加热、电势屏蔽、静电堵漏轴对称串级镜端塞的研究。 相似文献
88.
89.
90.
The surface integral formulation is a flexible, multiscale and accurate tool to simulate light scattering on nanostructures. Its generalization to periodic arrays is introduced in this paper. The general electromagnetic scattering problem is reduced to a discretizated model using the Method of Moments on the surface of the scatterers in the unit cell. The study of the resonances of an array of bowtie antennas illustrates the main features of the method. When placed into an array, the bowtie antennas show additional resonances compared to those of an individual antenna. Using the surface integral formulation, we are able to investigate both near-field and far-field properties of these resonances, with a high level of accuracy. 相似文献