718 research outputs found

    On the training of specialists in the creation and maintenance of software for processing and presentation of geospatial data

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    Показана актуальність відкриття підготовки в вузах Білорусі програмістів геодезичного профілю.=The relevance of the opening of training in the universities of Belarus for geodetic programmers is shown

    Radioluminescence properties of nanocomposite scintillators with BaF 2 fillers

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    In this paper, studies of the luminescence properties of nanocrystalline BaF 2 samples synthesized by laser ablation and pulse electron beam evaporation method are presented. The measurements of X-ray excited luminescence (XEL) showed the dependence between luminescence intensity and the shape of the spectrum on the morphology and particle size. Also, studies of X-ray excited luminescence, decay curves and optical transmittance for nanocomposite materials containing BaF 2 nanopowder are presented. Barium fluoride nanopowder, obtained by pulsed electron beam evaporation method is characterized by a lower intensity than the initial microcrystalline powder, but at the same time, XEL spectrum of the nanocomposite material with this nanocrystalline filler is more intense, then that for nanocomposite material with initial powder. © Published under licence by IOP Publishing Ltd

    Ultrafast hybrid nanocomposite scintillators: A review

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    In recent years, demand for scintillation detectors with high time resolution (better than 100 ps) has emerged in high-energy physics and medical imaging applications. In particular, time of flight positron emission tomography (TOF-PET) can greatly benefit from increasing time resolution of scintillators, which leads to the increase of signal-to-noise ratio, decrease of patient dose, and achievement of the superior spatial resolution of PET images. Currently, extensive research of various types of materials is carried out to achieve the best time resolution. In this review, the recent progress of various approaches is summarized and scintillation compounds with the best temporal characteristics are first reviewed. The review presents the physical processes causing fast luminescence in inorganic and organic materials. Special attention is paid to nanocomposites which belong to a new perspective class of scintillating materials, consisting of a plastic matrix, inorganic nanocrystalline fillers, and organic or inorganic luminescence activators and shifters. The main features and functions of all parts of existing and prospective nanocomposite scintillators are also discussed. A number of currently created and investigated nanocomposite materials with various compounds and structures are reviewed. © 2021 Elsevier B.V.Eesti Teadusagentuur, ETAg: PRG111, PRG629; European Regional Development Fund, ERDF: 2014-2020.4.01.15–0011, TK141Authors thank Minobrnauki project FEUZ-2020-0059 and Estonian Research Council (grants PRG629 and PRG111 ) for financial support. Authors are also grateful for partial support from the European Regional Development Fund (DoRA Pluss program) and the ERDF funding in Estonia granted to the Center of Excellence TK141 “ Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics ” (project No. 2014-2020.4.01.15–0011 )

    Coherent Cherenkov radiation as an intense THz source

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    Diffraction and Cherenkov radiation of relativistic electrons from a dielectric target has been proposed as mechanism for production of intense terahertz (THz) radiation. The use of an extremely short high-energy electron beam of a 4th generation light source (X-ray free electron laser) appears to be very promising. A moderate power from the electron beam can be extracted and converted into THz radiation with nearly zero absorption losses. The initial experiment on THz observation will be performed at CLARA/VELA FEL test facility in the UK to demonstrate the principle to a wider community and to develop the radiator prototype. In this paper, we present our theoretical predictions (based on the approach of polarization currents), which provides the basis for interpreting the future experimental measurements. We will also present our hardware design and discuss a plan of the future experiment

    Effect of self-organization and properties of aqueous disperse systems based on the moss peptide PpCLE2 in a low concentration range on the growth of Arabidopsis thaliana roots

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    © 2017, Springer Science+Business Media, LLC, part of Springer Nature. It is shown for the first time using a complex of physicochemical methods (dynamic and electrophoretic light scattering, conductometry, pH-metry) that below a threshold concentration of 1.0•10 –7 mol L –1 the disperse phase of the aqueous systems based on moss peptide PpCLE2 undergoes the domain—nanoassociate rearrangement, which affects the nonmonotonic concentration dependences of the specific electrical conductivity and pH and can result in a multidirectional profile of the dependence of the growth of the primary and lateral roots of the Arabidopsis thaliana seed plant in the range of calculated concentrations from 1.0•10 –6 to 1.0•10 –12 mol L –1

    NMR metabolic profiling of the liver following administrationof alcohol andthemushroom Ganoderma lucidum in rats

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    We have evaluated the efficiency of a metabonomic approach to metabolic phenotyping and detection of early metabolic changes under a toxic influence. For this purpose, a metabolic profiling of rat liver was performed with 1H NMR spectroscopy. Rat tissues from animals in three groups were analyzed. Group C consisted of control animals; animals in group A received alcohol repeatedly (15 % ethanol); and animals in group A+ R received alcohol in combination with a hepatoprotective herbal medicine (Reishi, Ganoderma lucidum) repeatedly. Noteworthy, alcohol consumption did not cause pathological changes, but stimulated hepatocyte proliferation. Our data suggest that changes in metabolite concentrations in A represent a typical metabolic response to alcohol consumption, namely decrease in glycine, leucine, isoleucine, valine, choline and lactate content, and increase in TMAO content. Treatment with Reishi (A+ R) had positive effects, in that it restored the levels of glycine, valine and TMAO. Furthermore, increase in NAD, ATP, UTP, succinate, pyranose, and acetate concentrations was observed in A+ R. A correlation was found between the valine, isoleucine, lactate, cho­line, and pyranose content and the num­ber of binuclear hepatocytes. Binuclear hepatocytes indicate proliferative activity, and the concentration of the metabolites participating in the formation of new hepatic cells decreases. Thus, the study of liver tissues by 1H NMR spectroscopy allows for detection of early changes in metabolite concentra­tions following chronic consumption of alcohol at insignificant doses. Consequently, 1H NMR spectro­scopy can serve as a promising approach to detecting alcohol-related liver pathologies and assessing the efficiency of the therapy used
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