349 research outputs found

    The study of amplitude and phase relaxation impact on the quality of quantum information technologies

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    The influence of amplitude and phase relaxation on evolution of quantum states within the formalism of quantum operations is considered. The model of polarizing qubits where noises are determined by the existence of spectral degree of freedom that shows up during the light propagation inside anisotropic mediums with dispersion is studied. Approximate analytic model for calculation of phase plate impact on polarizing state with dispersion influence taken into consideration is suggested.Comment: 7 pages, 4 figures, report for the International Symposium "Quantum Informatics-2014" (QI-2014), Zvenigorod, Moscow region, October 06-10, 201

    Self-supervised Physics-based Denoising for Computed Tomography

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    Computed Tomography (CT) imposes risk on the patients due to its inherent X-ray radiation, stimulating the development of low-dose CT (LDCT) imaging methods. Lowering the radiation dose reduces the health risks but leads to noisier measurements, which decreases the tissue contrast and causes artifacts in CT images. Ultimately, these issues could affect the perception of medical personnel and could cause misdiagnosis. Modern deep learning noise suppression methods alleviate the challenge but require low-noise-high-noise CT image pairs for training, rarely collected in regular clinical workflows. In this work, we introduce a new self-supervised approach for CT denoising Noise2NoiseTD-ANM that can be trained without the high-dose CT projection ground truth images. Unlike previously proposed self-supervised techniques, the introduced method exploits the connections between the adjacent projections and the actual model of CT noise distribution. Such a combination allows for interpretable no-reference denoising using nothing but the original noisy LDCT projections. Our experiments with LDCT data demonstrate that the proposed method reaches the level of the fully supervised models, sometimes superseding them, easily generalizes to various noise levels, and outperforms state-of-the-art self-supervised denoising algorithms.Comment: 13 pages, 12 figures. Under revie

    Application of secondary ion mass spectrometer for measuring the diffusion profiles in alkali-halide crystals

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    Depth profiles of magnesium, fluorine and oxygen impurities was examined in the surface layers of alkali-halide KBr crystals using method of secondary ion mass spectrometry. Samples of potassium bromide, coated with a surface film of magnesium fluoride were subjected to isothermal diffusion annealing in air at various times. It is shown that the diffusion of O ions occurs from the ambient atmosphere besides the diffusion of Mg and F ions during annealing of KBr crystals. Accurate estimation of the diffusion coefficients of cationic impurity Mg requires taking into account the possible interaction of this impurity and oxygen

    The information model "social explosion"

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    Article is dedicated to examination and analysis of the construction of the information model «social explosion», which corresponds to the newest «colored» revolutions. The analysis of model makes it possible to see effective approaches to the initiation of this explosion and by the use of contemporary information communications as honeycomb connection and the mobile Internet

    Zdokonalené metody pro snímání obrazových dat a analýzu tkání a buněk pomocí konfokální a multifotonové mikroskopie

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    Univerzita Karlova v Praze Přírodovědecká fakulta Studijní program: Vývojová biologie (P1520) Studijní obor: Vývojová biologie (1501V000) Oleksandr Chernyavskiy Zdokonalené metody pro snímání obrazových dat a analýzu tkání a buněk pomocí konfokální a multifotonové mikroskopie Improved Methods of Image Acquisition and Analysis of Tissues and Cells by Confocal and Multi-Photon Microscopy Abstrakt disertační práce Školitel: RNDr. Lucie Kubínová CSc Praha, 2015 Abstract The aim of this study was to develop methods and approaches for image acquisition with subsequent image analysis of data, obtained by confocal and two- photon excitation microscopy as well as their combination, enabling new possibilities of visualization and assessment of information on biological tissues and cell structures in 3D and their measurement. We focused on methods that exploited advantages of confocal and multi-photon excitation microscopy. Our further aim was to demonstrate the applicability of non-invasive approach for in vivo applications, usefulness and the relevance of these methods in several special biological applications with emphasis on improved image acquisition, analysis and evaluation of real biological specimens. The present work was not oriented on just one specific biological problem, but rather to methodological...Univerzita Karlova v Praze Přírodovědecká fakulta Studijní program: Vývojová biologie (P1520) Studijní obor: Vývojová biologie (1501V000) Oleksandr Chernyavskiy Zdokonalené metody pro snímání obrazových dat a analýzu tkání a buněk pomocí konfokální a multifotonové mikroskopie Improved Methods of Image Acquisition and Analysis of Tissues and Cells by Confocal and Multi-Photon Microscopy Abstrakt disertační práce Školitel: RNDr. Lucie Kubínová CSc Praha, 2015 Souhrn Cílem této práce bylo vyvinout metody a přístupy snímání mikroskopických obrázků konfokální, multifotonovou mikroskopií a jejich kombinací, s následnou analýzou dat umožňující nové způsoby vizualizace a měření biologických tkání a buněčných struktur ve 3D. Zaměřili jsme se na metody, využívající výhod konfokální a multifotonové mikroskopie. Naším dalším cílem bylo ukázat použitelnost neinvazivních přístupů v aplikacích in vivo, užitečnost a význam těchto metod pro několik konkrétních biologických aplikací, s důrazem na zdokonalené metody snímání mikroskopických obrázků, analýzu a hodnocení reálných biologickych preparátů. Tato práce nebyla zaměřena na řešení konkrétního biologického problému, ale na metodologický přínos pro několik druhů biologických problémů. Ve výsledku bylo vyvinuto několik pokročilých metod snímání multifotonovou mikroskopii....Department of Cell BiologyKatedra buněčné biologieFaculty of SciencePřírodovědecká fakult
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