91 research outputs found

    Prospects in Analytical Atomic Spectrometry

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    Tendencies in five main branches of atomic spectrometry (absorption, emission, mass, fluorescence and ionization spectrometry) are considered. The first three techniques are the most widespread and universal, with the best sensitivity attributed to atomic mass spectrometry. In the direct elemental analysis of solid samples, the leading roles are now conquered by laser-induced breakdown and laser ablation mass spectrometry, and the related techniques with transfer of the laser ablation products into inductively-coupled plasma. Advances in design of diode lasers and optical parametric oscillators promote developments in fluorescence and ionization spectrometry and also in absorption techniques where uses of optical cavities for increased effective absorption pathlength are expected to expand. Prospects for analytical instrumentation are seen in higher productivity, portability, miniaturization, incorporation of advanced software, automated sample preparation and transition to the multifunctional modular architecture. Steady progress and growth in applications of plasma- and laser-based methods are observed. An interest towards the absolute (standardless) analysis has revived, particularly in the emission spectrometry.Comment: Proofread copy with an added full reference list of 279 citations. A pdf version of the final published review may be requested from Alexander Bol'shakov <[email protected]

    Gaseous phase monitoring during reactive sputtering of yttrium in glow discharges

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    Regional adaptation of a dynamic global vegetation model using a remote sensing data derived land cover map of Russia

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    The dynamic global vegetation model (DGVM) SEVER has been regionally adapted using a remote sensing data-derived land cover map in order to improve the reconstruction conformity of the distribution of vegetation functional types over Russia. The SEVER model was modified to address noticeable divergences between modelling results and the land cover map. The model modification included a light competition method elaboration and the introduction of a tundra class into the model. The rigorous optimisation of key model parameters was performed using a two-step procedure. First, an approximate global optimum was found using the efficient global optimisation (EGO) algorithm, and afterwards a local search in the vicinity of the approximate optimum was performed using the quasi-Newton algorithm BFGS. The regionally adapted model shows a significant improvement of the vegetation distribution reconstruction over Russia with better matching with the satellite-derived land cover map, which was confirmed by both a visual comparison and a formal conformity criterion

    Multiscale Content-Based Image Retrieval for Whole-Slide Histological Images

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    Some features of linear scanning of the chemical composition of mineral aggregates using LA-ICP-MS: the modes and limits of the method

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    A routine linear and 2D scanning procedure using the inductively coupled plasma mass spectrometry with laser ablation (LA-ICP-MS) is often used when studying the composition of zonal and polyphase solid objects (crystals, rocks, alloys, etc.). However, the proper interpretation of the data necessitates taking into account the features inherent to the procedure. One of the most important features of the results obtained for the objects contrasting in composition is the asymmetry of the concentration profile of elements when going from high to low and, to a lesser extent, when going from low to high contents. Physical processes accompanying the analysis of rocks with the aforementioned features are considered. The duration of the time of signal distortion upon change of one crystal phase to another at large differences in the content of elements is estimated. To obtain the correct data for linear and 2D scanning using LA-ICP-MS, the scanning should be performed point by point: to avoid the influence of crater effects, points should be spaced 1.5 – 2.0 laser beam diameter apart. The goal of obtaining of reliable results requires also keeping the time intervals between measurements of at least 2 – 5 sec.</jats:p
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