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291.
The effect of a dispersed phase in reducing the concentration polarization in a membrane tube has been studied. The presence of a dispersed phase seems to have an effect in controlling the size of eddy formation and the rate of energy dissipation in the fluid medium. The role of eddy length and the energy dissipation rate on the mass transfer coefficient is discussed. Theoretical results obtained for the mass transfer coefficient and for the concentration polarization in the case of gelatin ultrafiltration are compared with the existing experimental results. The theoretical predictions seem to be in good agreement with the experimentally observed results. 相似文献
292.
Alfredo De Rossi Gaetano Assanto Stefano Trillo William E. Torruellas 《Optics Communications》1998,150(1-6):390-398
We have identified a family of (2+1)D spatial solitary waves which can stably propagate in bulk media in the presence of coexisting diffraction, self-focusing Kerr and quadratic nonlinearities. In a conspicuous range of excitation conditions close to the stationary solutions, the emerging wavepackets are immune to the detrimental occurrence of filamentation and collapse, typical of pure Kerr media. The presence of a second-order contribution to the cubic nonlinear response is, therefore, able to prevent optical damage in applications relying on self-guidance. We show that the cross-phase modulation plays an important effect on stability. Our estimate shows that the effects of the cubic susceptibility cannot be neglected below a certain beam size in realistic crystals (e.g. KTP or similar). 相似文献
293.
A new thin-film electro-optic switch employing two stable states of polarization is proposed and investigated. The design can be further employed to realize a TE-TM polarization converter by constructing a Mach-Zehnder type interferometer integrated optical switch. The limitations and design procedures for electro-optic devices are also discussed. 相似文献
294.
Lejeune C Coelho C Bonhomme-Coury L Azaïs T Maquet J Bonhomme C 《Solid state nuclear magnetic resonance》2005,27(4):242-246
We show that it is possible to efficiently transfer magnetization from 31P to 29Si, using variable amplitude CP MAS experiment. This experiment is demonstrated by using Si5O(PO4)6, the synthesis protocol of which is described. From the obtained results, we show that the experiment allows the spectral edition of 29Si spectra from 31P→29Si CP, enabling the studies of derivatives involving Si–O–P linkages, such as phosphosilicate glasses, microporous silicoaluminophosphates (SAPO) and bioactive phosphosilicates. 相似文献
295.
The phenomenon of elliptical polarization of the linearly polarized radiation reflected near the Brewster angle by the leaves of plants has been investigated. It has been shown that the appearance of ellipticity is associated with the complex structure of the cuticle.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 236–240, March–April, 2005. 相似文献
296.
We investigate the effects of a weak gravitational wave, modelled as a gaussian wavepacket, on the polarization state of an
electromagnetic field enclosed in a cavity. Our approach is semiclassical, in that the electromagnetic field is described as a quantum field, while the gravitational perturbation is treated classically,
as a slightly curved background spacetime. Assuming that before the interaction the electromagnetic field has been prepared
in a given polarization state, we show that – due to the gravitational scattering with the wave – some photons having different
polarization states are found in the cavity at late times. Such polarization scattering has some resemblance with Thomson
scattering, well-known in Quantum Electrodynamics: hence the motivation for the title. We give a numerical estimate of the
resulting photon polarization spreading in the case of a typical gravitational burst from a final supernova rebound. We also
briefly comment about the possible influence of such gravitational scattering on the Cosmic Microwave Background (CMB) polarization. 相似文献
297.
Yu-Chia Hsu Huang-Cuang Lin Shyh-Lin Tsao 《International Journal of Infrared and Millimeter Waves》2005,26(6):921-935
In this paper, we successfully invented a polarization controlled light source for coherent or noncoherent fiber communication systems. The structure of our experiment includes 89C51 control board and feedback circuit which can stabilize states of polarization (SOPs) of output light. From the SOP modulation results, the given degree of polarization can be effectively controlled and the polarization state can be arbitrarily changed. 相似文献
298.
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300.
In the geometric optics approximation, we predict the effect of additional twisting of spinning particle trajectories in an absorbing medium. The effect is determined by the particle polarization (chirality) and the curvature of the particle trajectory. Using our results, we quantitatively estimate the deviation from the mirror reflection law for ultracold neutrons. 相似文献