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Copper(II) oxide was synthesized in a glass matrix by multiple cycles of impregnation of porous glass with an aqueous solution of copper nitrate, followed by dehydration and thermal decomposition of the salt. The electrical conductivity and its temperature dependences, measured during the progressive accumulation of copper(II) oxide in porous glass, are indicative of a gradual change from chains to 2D structures, eventually resulting in a conductive oxide monolayer.  相似文献   
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Temperature dependence of the proton conductivity of a 85 wt % solution of orthophosphoric acid in a set of porous glasses with predominant channel radii of 4.5, 9, 19, and 74 nm was studied. A method for saturating a wide-pore glass with a dehydrated acid is suggested. This method provides a conductivity on the order of 10−4–10−3 ohm−1 cm−1 in the temperature range 373–473 K.  相似文献   
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Acoustical Physics - The paper discusses reconstruction of the directivity pattern of a sound source in free space from measurements of the field excited by this source in a tank. The...  相似文献   
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Electrical conductivity of porous glasses saturated with sulfuric acid solutions was studied. At impregnating solution concentrations in the range 20–40 wt %, the glasses have high conductivities a σ > 0.1 ω?1 cm?1. The dependences of the electrical conductivity on parameters of the porous structure of membranes are considered.  相似文献   
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The ray method of calculating the mode amplitudes is used to analyze the sound fields in deep-water acoustic waveguides with two types of inhomogeneities of the refractive index: (i) weak inhomogeneities that cause small perturbations of ray trajectories and (ii) strong inhomogeneities with large spatial scales. Simple analytical relations are derived for describing the variations of the mode structure of the sound field in the presence of the aforementioned inhomogeneities. A new criterion defining the validity of the adiabatic approximation is formulated. To illustrate and test the results obtained, a numerical simulation of the sound fields is performed on the basis of the parabolic equation method.

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Hamiltonian formalism is used to analyze the effect of the mesoscale inhomogeneities of the ocean medium on the ray structure of the sound field. It is shown that the distortions of the structure of the sound field can be successfully estimated by a function that links the values of the canonical variables of the ray action before and after crossing the inhomogeneity. That function is calculated with the use of the standard ray code. Sound propagation through the synoptic eddy and frontal zone is considered.  相似文献   
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Numerical and analytical studies are performed on how unstable fluctuations of the parameters of the medium in a deep sea affect the focusing of sound pulses using the time reversal method. The simplest situation, when point sources and receivers are used for emission and reception, is considered. Pulse propagation in the direct and backward directions is numerically simulated by the parabolic equation method. Calculations are performed for sound signals with frequencies of several tens of hertz. It is shown that, in the presence of sound velocity fluctuations caused by random internal waves, noticeable attenuation of the field amplitude at the center of the focal spot can be observed beginning from distances of 200 to 400 km. As the central frequency of the pulsed signal increases, the effect of nonstationarity of the perturbation on the focusing is amplified. This phenomenon is explained qualitatively and quantitatively in the geometrical optics approximation.  相似文献   
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