831 research outputs found

    Signature of a silver phase percolation threshold in microscopically phase separated ternary Ge0.15Se0.85-xAgx (0 <= x <= 0.20) glasses

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    Temperature modulated Alternating Differential Scanning Calorimetric (ADSC) studies show that Se rich Ge0.15Se0.85-xAgx (0 <= x <= 0.20) glasses are microscopically phase separated, containing Ag2Se phases embedded in a Ge0.15Se0.85 backbone. With increasing silver concentration, Ag2Se phase percolates in the Ge-Se matrix, with a well-defined percolation threshold at x = 0.10. A signature of this percolation transition is shown up in the thermal behavior, as the appearance of two exothermic crystallization peaks. Density, molar volume and micro-hardness measurements, undertaken in the present study, also strongly support this view of percolation transition. The super-ionic conduction observed earlier in these glasses at higher silver proportions, is likely to be connected with the silver phase percolation.Comment: 4 pages, 7 figure

    Effect of nitrogenous bases on the thermal stability of jet fuels

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    Fuels from naphthenic petroleums were evaluated, and it was found that they had more N bases than those paraffinic ones (0.00024 and 0.000009% N, respectively). The removal of the N bases improved significantly the thermal stability and reduced the residue formation during oxidation of the fuel. The improvement depended on both content and composition of the bases. Thus, fuels with similar content of N bases (0.00058% N) and thermal stability had oxidation residues of 17.5 and 5.6 and sol. gum of 13 and 1.5 mg/100 ml, before and after removing the N bases, respectively

    Из истории становления терминологии языка саха (на материале словарей изданных в 1920-1980 гг.)

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    The article has a history of the formation and development of Sakha terminology on the material of dictionaries published from 1920 to 1980. The authors considered the stages: “Formation of the basics of terminological vocabulary” (1920-1940) and “The third industrial (transitional) stage” (1940-1980). The stages of the formation and development of the terminology of the Yakut literary language are described. The analysis of the development of the historical situation of periods is given. Key words: component parts (inventory and interpretation) parameters, modifications, translations and interpretation of the meaning of terms in the form of definitions.Keywords: Yakut language, terminology, dictionary, equivalent, affix, phrases.В статье рассматривается история становления и развития терминологии языка саха на материале словарей изданных с 1920 по 1980 гг. Авторы рассмотрели этапы: «Формирование основ терминологической лексики» (1920-1940 гг.) и «Третий индустриальный (переходный) этап» (1940-1980 гг.). Описываются этапы становления и развития терминологии якутского литературного языка. Дается анализ развития исторической обстановки периодов. Описано качество словников словарей, их композиционные (инвентаризационные и интерпретационные) параметры, модификации приемов перевода и интерпретация значения терминов в виде дефиниций. Ключевые слова: Якутский язык, терминология, словарь, эквивалент, аффикс, словосочетания.

    Disturbances of electron density in the high latitude upper (F-region) ionosphere induced by X-mode HF pump waves from EISCAT UHF radar observations

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    The paper presents experimental results concerning disturbances of electron density in the high latitude ionosphere F-region, induced by powerfulHF radio waves (pump waves) with extraordinary (X-mode) polarization. The experiments were carried out at the EISCAT/Heating facility at Tromsø, Norway. The EISCAT UHF incoherent scatter radar (ISR), running at 930 MHz, co-located with a heating facility, was used to detect the disturbances of electron density. In the course of the experiments, the X-mode HF pump waves radiated into the F-region towards the magnetic zenith at different pump frequencies and ratios of the pump frequency to the critical frequency of the F2 layer.The effective radiated power was ERP = 360–820 MW. An increase in electron densities was found in a wide altitude range, giving rise to field-aligned ducts with enhanced electron density. The features and behavior of the ducts were investigated. It was revealed that the ducts are formed under quiet background geophysical conditions in a wide altitude range up to the upper altitude limit of EISCAT ISR measurements, when the pump frequencies were both below and above the critical frequency of the F2 layer (fH ≤ foF2 or fH &gt; foF2). A plausible formation mechanism of the ducts is discussed.Представлены результаты экспериментальных исследований возмущений электронной концентрацииNe в высокоширотной F-области ионосферы, вызванные воздействием мощных КВ-радиоволн необыкновенной (Х-мода) поляризации. Эксперименты выполнялись на КВ нагревном стенде EISCAT/ Heating в г. Тромсё, Норвегия при эффективной мощности излучения 360–820 МВт. В качестве средства диагностики возмущений Ne использовался EISCAT радар некогерентного рассеяния радиоволн (НР) на частоте 930 МГц, пространственно совмещенный с КВ нагревным стендом. Обнаружено возрастание Ne в широком диапазоне высот, которое формирует каналы повышенной электронной плотности, вытянутые вдоль магнитного поля Земли. Исследованы характеристики и условия создания каналов. Обсуждается возможный механизм формирования каналов Ne при Х-нагреве высокоширотной F-области ионосферы

    Rapid identification of Corynebacterium diphtheriae clonal group associated with diphtheria epidemic, Russian Federation.

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    We used 199 Corynebacterium diphtheriae isolated from 1995 to 1997 in Russia to evaluate the ability of random amplified polymorphic DNA (RAPD) to identify the unique clonal group that emerged there in 1990. Our data show that RAPD can reliably, reproducibly, and rapidly screen a large number of strains to identify the epidemic clonal group

    Antiproliferative activity of a new derivative from the class of N-glycoside of indolo [2,3-a] pyrrolo [3,4-c] carbazoles

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    The aim of the study was to evaluate an antiproliferative activity of a new, Russian derivative of N-glycoside substituted indolocarbazole 6-amino-12-(α-L-arabinopyranosyl)indolo [2,3-a] pyrrolo [3,4-c] carbazole-5,7-dione (LCS-1208) on models of transplantable tumors of mice and on human tumors in Balb/c nude mic

    Leaf Mesophyll Structure and Photosynthetic Activity in Calla palustris L. from Natural Habitats with Different Level of Technogenic Pollution

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    A study of leaf structure and CO2 assimilation rate was conducted on the emergent plant Calla palustris L. from natural habitats with different levels of technogenic pollution (the Sak-Elga River, upstream and downstream of the Karabash copper smelter, Chelyabinsk region, Russia). It was found that both chlorophyll a content andthe rate of CO2 assimilation decreased twofold in plants from the downstream site. No significant changes were observed in leaf mesophyll structure and the volume of aerenchyma in the leaf. It was shown that in plants from strongly contaminated site, the decrease in spongy mesophyll cell volume was compensated by the increase in their number, whereas the decrease in the number of chloroplasts per cell was accompanied by a growth in volume. It is concluded that the changes in the numerical and dimensional characteristics of mesophyll cells and chloroplasts provide for the viability of C. palustris under prolonged technogenic impact and demonstrate the plasticity of the photosynthetic apparatus. Keywords: emergent plant, heavy metals, adaptation, leaf structure, CO2 uptak

    Spectroscopic determination of hole density in the ferromagnetic semiconductor Ga1x_{1-x}Mnx_{x}As

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    The measurement of the hole density in the ferromagnetic semiconductor Ga1x_{1-x}Mnx_{x}As is notoriously difficult using standard transport techniques due to the dominance of the anomalous Hall effect. Here, we report the first spectroscopic measurement of the hole density in four Ga1x_{1-x}Mnx_{x}As samples (x=0,0.038,0.061,0.083x=0, 0.038, 0.061, 0.083) at room temperature using Raman scattering intensity analysis of the coupled plasmon-LO-phonon mode and the unscreened LO phonon. The unscreened LO phonon frequency linearly decreases as the Mn concentration increases up to 8.3%. The hole density determined from the Raman scattering shows a monotonic increase with increasing xx for x0.083x\leq0.083, exhibiting a direct correlation to the observed TcT_c. The optical technique reported here provides an unambiguous means of determining the hole density in this important new class of ``spintronic'' semiconductor materials.Comment: two-column format 5 pages, 4 figures, to appear in Physical Review
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