418 research outputs found

    Foraminiferal biostratigraphy of the uppermost Campanian-Maastrichtian in SW Crimea (Bakhchisaray and Chakhmakhly sections)

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    A detailed foraminiferal distribution, resulting from bed by bed collecting of the Beshkosh and Chakhmakhly sections in SW Crimea, is studied for the first time. Many of the taxa - planktonic and benthic - are illustrated. A bioslraligraphieal analysis of the units XIX to XXIII (Upper Campanian - Maastricluian) and the correlation with other areas are discussed

    A local optimization technique for the solution of the problem of nonlinear seismic tomography

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    AbstractA new method for the solution of the inverse kinematic problem of seismics which is based on the local optimization approach is presented. The method has higher stability and performance in comparison to the known methods and can be well adapted to the real data

    One-dimensional Chern-Simons theory

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    We study a one-dimensional toy version of the Chern-Simons theory. We construct its simplicial version which comprises features of a low-energy effective gauge theory and of a topological quantum field theory in the sense of Atiyah.Comment: 37 page

    The solution of dynamic problems of elastic wave propagation in inhomogeneous media by a combination of partial separation of variables and finite-difference methods

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    A new method for the calculation of theoretical seismograms, which is suitable for a wide class of inhomogeneous media, is suggested. The method is based on a combination of partial separation of variables with finite-difference techniques. Different variants of the method, based on the application of the Fourier-Bessel transform, finite integral transforms, expansions in Legendre polynomials, etc., are discussed in detail. Examples of theoretical seismograms for various simple structures are presented.         ARK: https://n2t.net/ark:/88439/y045452 Permalink: https://geophysicsjournal.com/article/79 &nbsp

    Parametric x-ray radiation in polycrystals

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    Parametric X-ray radiation produced during the interaction of charged particles with polycrystals is regarded. A review of the existing theories, perspectives of application and performed experiments is presented. The evolution of experimental capabilities as well as the progress in the process comprehension is illustrated. The state of the art of PXR in polycrystals is presente

    Parametric x-ray radiation in the backward geometry

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    Parametric X-ray Radiation registered in the backward geometry is analysed. The main properties of the radiation for such geometry are discussed. The advantages of the backward geometry over other configurations regarding the intensity, the spectral width and the possibility to discriminate the contributions form different radiation mechanisms to the total radiation yield are presente

    Флора Дубны: культивируемые сосудистые растения

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    A list of cultivated vascular plants of Dubna (Moscow Region) including 342 species and hybrids from 74 plant families is presented.Приведен список культивируемых сосудистых растений г. Дубны (Московская область), который насчитывает 342 вида и гибрида из 74 семейств

    Ambiguities in the partial-wave analysis of pseudoscalar-meson photoproduction

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    Ambiguities in pseudoscalar-meson photoproduction, arising from incomplete experimental data, have analogs in pion-nucleon scattering. Amplitude ambiguities have important implications for the problems of amplitude extraction and resonance identification in partial-wave analysis. The effect of these ambiguities on observables is described. We compare our results with those found in earlier studies.Comment: 12 pages of text. No figure

    Parametric X-ray radiation in polycrystals

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    Parametric X-ray radiation produced during the interaction of charged particles with polycrystals is regarded. A review of the existing theories, perspectives of application and performed experiments is presented. The evolution of experimental capabilities as well as the progress in the process comprehension is illustrated. The state of the art of PXR in polycrystals is presented.Розглянуто параметричне рентгенівське випромінювання (ПРВ), що виникає при взаємодії заряджених частинок з полікристалічними мішенями. Представлено огляд сучасного стану дослідження ПРВ в полікристалах: існуючих теорій, перспектив застосування і проведених експериментів з урахуванням розвитку експериментальних можливостей.Рассмотрено параметрическое рентгеновское излучение (ПРИ), возникающее при взаимодействии заряженных частиц с поликристаллическими мишенями. Представлен обзор современного состояния исследования ПРИ в поликристаллах: существующих теорий, перспектив применения и проведенных экспериментов с учетом развития экспериментальных возможностей

    Parametric X-ray Radiation in the backward geometry

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    Parametric X-ray Radiation registered in the backward geometry is analysed. The main properties of the radiation for such geometry are discussed. The advantages of the backward geometry over other configurations regarding the intensity, the spectral width and the possibility to discriminate the contributions form different radiation mechanisms to the total radiation yield are presented.Аналізується параметричне рентгенівське випромінювання, зареєстроване в геометрії «строго назад». Обговорюються основні властивості випромінювання для такої геометрії. Представлено переваги геометрії «строго назад» у порівнянні з іншими геометріями в залежності від інтенсивності, спектральної ширини і можливості поділу внесків від різних механізмів випромінювання в загальний вихід випромінювання.Анализируется параметрическое рентгеновское излучение, зарегистрированное в геометрии «строго назад». Обсуждаются основные свойства излучения для такой геометрии. Представлены преимущества геометрии «строго назад» по сравнению с другими геометриями в зависимости от интенсивности, спектральной ширины и возможности разделения вкладов от различных механизмов излучения в общий выход излучения
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