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141.
Tavrov A Korablev O Ksanfomaliti L Rodin A Frolov P Nishikwa J Tamura M Kurokawa T Takeda M 《Optics letters》2011,36(11):1972-1974
To suppress starlight for direct exoplanet observation, we propose a common-path achromatic rotational-shearing coronagraph (CP-ARC), which is an interferocoronagraph with an angular-adjustable field rotator. The CP-ARC aims to maintain unwanted detection of stellar light, which can be suppressed incompletely by interference because of the finite diameter of the star. Compared to the previous interferocoronagraph, which had a nonadjustable 180° field rotation, the proposed CP-ARC can improve the coronagraphic contrast by several orders if the CP-ARC is combined with medium or large telescopes where the companion-star separation is optically resolved by more than a few Airy radii. The CP-ARC is made robust against mechanical disturbances due to the common-path interferometer principle. 相似文献
142.
We obtain a complete asymptotic expansion of the integrated density of states of operators of the form ${H = (-\Delta)^w+ B}$ in ${\mathbb{R}^d}$ . Here w > 0 and B belong to a wide class of almost-periodic self-adjoint pseudo-differential operators of order less than 2w. In particular, we obtain such an expansion for magnetic Schrödinger operators with either smooth periodic or generic almost-periodic coefficients. 相似文献
143.
Leonid G. Voskressensky Larisa N. KulikovaSergey V. Gozun Victor N. KhrustalevTatiana N. Borisova Anna V. ListratovaMaxim V. Ovcharov Alexey V. Varlamov 《Tetrahedron letters》2011,52(32):4189-4191
The first synthesis of tetrahydrochromeno[4,3-d]azocines via an alkyne-induced expansion reaction is described. 相似文献
144.
A model of adsorption of the Naproxen enantiomers on the (S,S)-Whelk-O1 chiral stationary phase that we recently proposed was found to be inconsistent with new experimental data. A new model taking into account the variation of the dissociation coefficient of the analyte during elution of the band is discussed. 相似文献
145.
Yury Yu. Rusakov Leonid B. Krivdin Stephan P. A. Sauer Ekaterina P. Levanova Galina G. Levkovskaya 《Magnetic resonance in chemistry : MRC》2010,48(1):44-52
Experimental measurements and second‐order polarization propagator approach (SOPPA) calculations of 77Se? 1H spin–spin coupling constants together with theoretical energy‐based conformational analysis in the series of 2‐substituted selenophenes have been carried out. A new basis set optimized for the calculation of 77Se? 1H spin–spin coupling constants has been introduced by extending the aug‐cc‐pVTZ‐J basis for selenium. Most of the spin–spin coupling constants under study, especially vicinal 77Se? 1H couplings, demonstrated a remarkable stereochemical behavior with respect to the internal rotation of the substituent in the 2‐position of the selenophene ring, which is of major importance in the stereochemical studies of the related organoselenium compounds. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
146.
Dennis A. Veselkov Leonid Karawajew Alexei N. Veselkov David B. Davies 《Molecular physics》2013,111(18):1933-1942
1H?NMR spectroscopy at 500?Mhz has been used to determine the structures and thermodynamics in aqueous salt solution of the hetero-association of Daunomycin (DAU) with a series of phenanthridine dyes having different numbers of amino/azido groups in the chromophore, together with the self-association of the phenthridine dyes under the same solution conditions (0.1?M phosphate buffer, pD 7.1, 298?K). The NMR measurements have been analyzed using statistical-thermodynamical models of both self-association and hetero- association in which no limitation is set on the size of molecular stacks. In this work the magnitudes of the self-association parameters of Ethidium Bromide (EB) and its azido-derivatives, 8-azido-Ethidium Bromide (EMB) and 3,8-diazido-Ethidium Chloride (EDC), show a successive decrease with mono- and di-substitition of the 3,8-amino groups of EB. A similar pattern is observed for the equilibrium constants for hetero-association of the phenanthridines with DAU. The thermodynamical and structural parameters of hetero-association of the phenanthridines with DAU are consistent with an intermolecular hydrogen bond between the 3,8 amino-groups of EB and the 9MeCO group of DAU contributing to the stability of the hetero-complex in aqueous solution. 相似文献
147.
148.
Kh. Z. Brainina Leonid Gdalievich Galperin Ludmila Aleksandrovna Piankova Natalia Yurievna Stozhko Aidar Marksovich Myrzakaev Olga Romanovna Timoshenkova 《Journal of Solid State Electrochemistry》2011,15(11-12):2469-2475
The article presents the findings of microscopic and electrochemical studies of electrooxidation of bismuth particle of varying sizes. Bismuth particles were immobilized on the surface of indifferent carbon containing screen-printed electrodes. The calculations and experimental studies demonstrated that the transition from macroparticles to nanoparticles caused a shift of the maximum current potential of bismuth oxidation into the area with more negative potentials. A positive correlation between experimental and calculated data confirms once again a relevant application of the earlier proposed mathematical model and the possible use of the shift of the maximum current potential of electrooxidation to describe electrochemical activity and energy properties of metal nanoparticles. 相似文献
149.
V. N. Chekhov 《International Applied Mechanics》2011,46(12):1351-1361
The equilibrium state of layered bodies under biaxial loading is analyzed for stability. It is assumed that the in-plane strains
in the layers are zero. The three-dimensional linearized theory of stability and the piecewise-homogeneous material model
are used. Two models of layered bodies are considered. Specific problems for layered bodies of different structure are solved.
The critical load and wave number that cause instability of layered bodies are found 相似文献
150.
Abstract— The sieve effect and scattering within leaves are analysed by the use of a simple model. By plotting the leaf transmittance (corrected for light not entering the leaf) vs the transmittance of an equivalent amount of homogeneous plastid pigments, an intercept is found where the latter is zero. This minimum transmittance represents the fraction of the leaf area devoted to the ray of the sieve effect which strikes no chloroplasts. It varied between 7% and 0.2% in non-senescent leaves. When this was subtracted from the leaf spectrum, the peak absorbance was greater than that of the homogeneous leaf pigments in all cases. The ratio of the leaf absorbance to that of the homogeneous pigments, at the same wavelength, is the apparent optical pathlength, which increases with decreasing absorbance. By plotting this ratio vs the absorbance of the equivalent homogeneous pigment, an intercept is found where the latter is zero. This intercept is interpreted as an estimate of the true mean scattering pathlength. Leaves with high chlorophyll contents had low pathlengths (mean and SD = 2.30 ± 0.25); with moderate and low contents, the values were higher (2.75 ± 0.28, 3.95 ± 0.77). Another application of the model gave values between 3 and 4 for the true scattering pathlength. 相似文献