212 research outputs found

    Introspective and traditional views of language

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    The present-day traditional view of language has an essentially pedagogical background inherited from antiquity. Certain features of this heritage have passed through the centuries, reached our days and continue to be a sort of implicit postulates penetrating almost into every scientific conception of language. This causes specific divergences between the scientific view of language and its introspective view, i.e., the way it is actually conceived by an individual during ordinary communication. Studying those divergences is important for a better grasping the nature of natural language and for a more adequate approaching to certain problems

    Synthesis and characterization of ZnBTC-based MOFs: effect of solvents and salt

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    In this work, we studied the optimization of synthetic approaches to creating structurally modified metal-organic frameworks under various synthesis conditions. We investigated the influence of the various solvents and zinc salts on the structural characteristics of the metal-organic framework based on benzene-1,3,5-tricarboxylic acid (H3BTC). The results indicate that the variation of the types of both solvent and salt is a parameter affecting the crystallinity, phase purity, and morphology of the metal-organic framework. This was confirmed by comprehensive structural characterization (SEM, EDX, PXRD)

    Nanothermal characterization of amorphous and crystalline phases in chalcogenide thin films with scanning thermal microscopy

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    The thermal properties of amorphous and crystalline phases in chalcogenide phase change materials (PCM) play a key role in device performance for non-volatile random-access memory. Here, we report the nanothermal morphology of amorphous and crystalline phases in laser pulsed GeTe and Ge2Sb2Te5 thin films by scanning thermal microscopy (SThM). By SThM measurements and quantitative finite element analysis simulations of two film thicknesses, the PCM thermal conductivities and thermal boundary conductances between the PCM and SThM probe are independently estimated for the amorphous and crystalline phase of each stoichiometry

    Metal-Organic Frameworks for Metal-Ion Batteries: Towards Scalability

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    Metal-organic frameworks (MOFs), being a family of highly crystalline and porous materials, have attracted particular attention in material science due to their unprecedented chemical and structural tunability. Next to their application in gas adsorption, separation, and storage, MOFs also can be utilized for energy transfer and storage in batteries and supercapacitors. Based on recent studies, this review describes the latest developments about MOFs as structural elements of metal-ion battery with a focus on their industry-oriented and large-scale production

    Effect of nitric acid modification of montmorillonite clay on synthesis of solketal from glycerol and acetone

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    [EN]The effect of acid modification of a natural montmorillonite clay (MM) by HNO3 on the catalytic properties of MM from Dash-Salakhlinsk (Kazakhstan) has been investigated in the synthesis of solketal from glycerol and acetone in solvent free and acetonitrile media. HNO3 concentration allowed to control the chemical composition, the surface acidity, the porous structure of the acid-activated MMs and their catalytic performance. The main reaction product was solketal with 86.6–98% selectivity. Conversion of glycerol depended on the Brønsted acidity. The most active sample, namely, MM activated with 0.5 mol/dm3 HNO3, showed good reusability for 3 catalyst cycle

    Fenton degradation of sulfanilamide in the presence of Al,Fe-pillared clay: Catalytic behavior and identification of the intermediates

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    [EN]Liquid phase catalytic degradation of sulfanilamide with H2O2 was carried out in the presence of Fe,Al/M-pillared clay (Fe,Al/M-MM, M = Na+, Ca2+ and Ba2+) as heterogeneous Fenton type catalyst. Fe,Al/M-MMs were prepared by swelling of layered aluminosilicate (90–95 wt.% montmorillonite) from a bed located in Mukhortala (Buryatia, Russia) in Na+, Ca2+ and Ba2+ forms by means of the exchange of these cations with bulky Fe,Al-polyoxocations prepared at Al/Fe = 10/1 and OH/(Al + Fe) = 2.0, and then calcinated at 500 °C. XRD method and chemical analysis demonstrated that the rate of crystalline swelling was dependent on the interlayer cations and decreased in the order: Fe,Al-/Na-MM > Fe,Al/Ca-MM > Fe,Al/Ba-MM. It was found that the catalytic properties of Fe,Al/M-MMs depended on the type of exchangeable cations. The effect of the H2O2/sulfanilamide molar ratio, the catalyst content, the reaction temperature and the reaction pH on the removal rate of sulfanilamide has been studied in the presence of Fe,Al/Na-MM. The catalyst can be applied for degradation of sulfanilamide with H2O2 for at least three successive cycles without loss of activity. HPLC analyses pointed out that the main degradation intermediate products were sulfanilic acid, benzenesulfonic acid, p-benzoquinone and aliphatic carboxylic acids
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