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961.
Yangjian Cai Q. Lin H. T. Eyyubo?lu Y. Baykal 《Applied physics. B, Lasers and optics》2009,94(2):319-325
The propagation of an elliptical Gaussian beam (EGB) through an astigmatic ABCD optical system in a turbulent atmosphere is
investigated. An analytical formula for the average intensity of an EGB and a generalized tensor ABCD law for the generalized
complex curvature tensor are derived. As an application example, we derived an analytical formula for the average intensity
of an elliptical flat-topped beam propagating through an astigmatic ABCD optical system in a turbulent atmosphere. As a numerical
example, the focusing properties of an EGB focused by a thin lens in a turbulent atmosphere are studied. It is found that
the focused beam at the focal plane becomes a circular Gaussian beam when the atmospheric turbulence is strong enough, and
the beam width of the circular Gaussian beam is determined by atmospheric turbulence strength, focal length of the thin lens,
and wavelength of the initial beam but is independent of the initial beam widths (i.e., initial intensity distribution). 相似文献
962.
S. Ertman A. Czapla T. R. Woliński T. Nasi?owski H. Thienpont E. Nowinowski-Kruszelnicki R. D?browski 《Opto-Electronics Review》2009,17(2):150-155
Photonic liquid crystal fibers have already been demonstrated as a promising perspective for creation of new classes of dynamically
tunable optical fiber devices. By combining different geometries of photonic crystal fibers with a variety of different liquid
crystals it is possible to obtain a new generation of fibers with dynamically tunable properties, e.g., transmission spectra,
attenuation or dispersion.
In this paper, tunable birefringence in a commercially available highly birefringent Blazephotonics PM-1550-01 photonic crystal
fiber selectively filled with a low birefringence liquid crystal has been experimentally demonstrated. Theses experimental
results have been compared with simulations based on the multipole method. 相似文献
963.
Hongbo Fu Shaogui Yang Shicheng Zhang Zhijian Zheng 《Journal of Applied Spectroscopy》2009,76(2):227-233
A series of nanosized Bi2WO6 catalysts was synthesized using various starting materials, and they were characterized by X-ray diffractometry, transmission
electron microscopy, and diffuse reflectance spectroscopy. Rhodamine-B (RhB) photodegradation in aqueous medium was employed
as a probe reaction to test the photoactivity of the as-prepared samples. Dependence of the photocatalytic activities on different
contents of the starting materials was examined under visible irradiation (λ > 400 nm). The sample prepared in the following
conditions: reaction time 24 h, the pH of the solution 7, the Bi3+ amount in the start precipitates 5 mmol — exhibited the highest photochemical activity when the hydrothermal temperature
was settled at 180°C.
Published in Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 2, pp. 243–249, Martch–April, 2009. 相似文献
964.
Andrzej Graja Iwona Olejniczak Boles?aw Barszcz John A. Schlueter 《Central European Journal of Physics》2009,7(4):663-667
Infrared and Raman investigations of two phases of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) based organic conductors
with the same CF3CF2SO3− anion: β′-(BEDT-TTF)2CF3CF2SO3 and δ′-(BEDT-TTF)2CF3CF2SO3, are shortly reviewed and compared with the most typical infrared properties of the family of (BEDT-TTF)2RR′SO3 organic conductors, where R = SF5, CF3, and R′ are CH2, CF2, CHF, CHFCF2, and CH2CF2. The role of the molecular structur and spatial organization of the counterions is discussed.
Presented at 2-nd International Conference on Functional Materials and Devices, ICFMD 2008, June 16–19, 2008, Kuala Lumpur,
Malaysia 相似文献
965.
S. Petrovi? B. Gakovi? D. Peru?ko T. Desai D. Batani M. ?ekada B. Radak M. Trtica 《Laser Physics》2009,19(8):1844-1849
Interaction of an Nd:YAG laser, operating at 532 nm wavelength and pulse duration of 40 ps, with tungsten-titanium (WTi) thin film (thickness, 190 nm) deposited on single silicon (100) substrate was studied. Laser fluences of 10.5 and 13.4 J/cm2 were found to be sufficient for modification of the WTi/silicon target system. The energy absorbed from the Nd:YAG laser beam is partially converted to thermal energy, which generates a series of effects, such as melting, vaporization of the molten material, shock waves, etc. The following WTi/silicon surface morphological changes were observed: (i) ablation of the thin film during the first laser pulse. The boundary of damage area was relatively sharp after action of one pulse whereas it was quite diffuse after irradiation with more than 10 pulses; (ii) appearance of some nano-structures (e.g., nano-ripples) in the irradiated region; (iii) appearance of the micro-cracking. The process of the laser interaction with WTi/silicon target was accompanied by formation of plasma. 相似文献
966.
In this paper, using the upper-lower solution method, we investigate the properties of periodic quasisolutions for time-periodic nonquasimonotone reaction-diffusion systems, and present some existence, asymptotic behavior results for two ecological models. 相似文献
967.
Set-valued dynamic systems and random iterations of set-valued weaker contractions in uniform spaces
K. W?odarczyk C. Obczyński D. Wardowski 《Journal of Mathematical Analysis and Applications》2006,318(2):772-780
Set-valued weaker contractions in uniform, locally convex and metric spaces are defined and dynamic systems of such weaker contractions are studied. Conditions guaranteeing the convergence of generalized sequences of random iterations and iterations and the existence and uniqueness of endpoints of set-valued weaker contractions are established. Our definitions and results are new for set-valued maps in uniform, locally convex and metric spaces and even for single-valued maps. 相似文献
968.
Dragana S. Cvetkovi?-Ili? Dragan S. Djordjevi? Yimin Wei 《Linear algebra and its applications》2006,418(1):53-61
In this paper we investigate additive properties of the generalized Drazin inverse in a Banach algebra. We find some new conditions under which the generalized Drazin inverse of the sum a + b could be explicitly expressed in terms of a, ad, b, bd. Also, some recent results of Castro and Koliha [New additive results for the g-Drazin inverse, Proc. Roy. Soc. Edinburgh Sect. A 134 (2004) 1085-1097] are extended. 相似文献
969.
This paper establishes a link between a generalized matrix Matsumoto-Yor (MY) property and the Wishart distribution. This link highlights certain conditional independence properties within blocks of the Wishart and leads to a new characterization of the Wishart distribution similar to the one recently obtained by Geiger and Heckerman but involving independences for only three pairs of block partitionings of the random matrix.In the process, we obtain two other main results. The first one is an extension of the MY independence property to random matrices of different dimensions. The second result is its converse. It extends previous characterizations of the matrix generalized inverse Gaussian and Wishart seen as a couple of distributions.We present two proofs for the generalized MY property. The first proof relies on a new version of Herz's identity for Bessel functions of matrix arguments. The second proof uses a representation of the MY property through the structure of the Wishart. 相似文献
970.
1.IntroductionPartialdifferentialequationssubjecttounilateralboundaryconditionsareusuallycalledSignoriniproblemsintheliterature.TheseproblemshavebeenstudiedbymanyauthodssincetheappearenceofthehistoricalpaperbyA.Signoriniin1933[25].Signoriniproblemsaroseinmanyareasofapplicationse.g.,theelasticitywithunilateralconditions[lo],thefluidmechnicsproblemsinmediawithsemipermeableboundaries[8,12],theelectropaintprocess[1]etc.Fortheexistence,uniquenessandregularityresultsforSignorinitypeproblemswerefer… 相似文献