1,050 research outputs found

    Temperature dependence of the electron spin g factor in GaAs

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    The temperature dependence of the electron spin gg factor in GaAs is investigated experimentally and theoretically. Experimentally, the gg factor was measured using time-resolved Faraday rotation due to Larmor precession of electron spins in the temperature range between 4.5 K and 190 K. The experiment shows an almost linear increase of the gg value with the temperature. This result is in good agreement with other measurements based on photoluminescence quantum beats and time-resolved Kerr rotation up to room temperature. The experimental data are described theoretically taking into account a diminishing fundamental energy gap in GaAs due to lattice thermal dilatation and nonparabolicity of the conduction band calculated using a five-level kp model. At higher temperatures electrons populate higher Landau levels and the average gg factor is obtained from a summation over many levels. A very good description of the experimental data is obtained indicating that the observed increase of the spin gg factor with the temperature is predominantly due to band's nonparabolicity.Comment: 6 pages 4 figure

    Communicative search for a way out of the impasse in cross-cultural communication: conditions for narrowing the "gaps" between the languages

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    The paper addresses the issue of linguistic differences in cross-cultural communication and discusses communicative strategies that could be used to mitigate them. The authors argue that lingua-didactic multicultural education can help remove the main obstacle in the traditional teaching of Russian as a foreign language (RFL) - a "clash of cultures"; and not only can introduce a model of teaching to write, read, and speak in Russian, but can also offer a system of instruction that will allow the students to understand the way Russians think, which surely would make it easier for them to "translate" a text from one culture into another in a non-native "cultural environment" providing a polylingual format for interactio

    Justice independence: foreign constitutional experiences

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    This article presents the results of a comparative legal study investigating the norms of constitution in CIS countries, Europe and America about formalizing the principle of justice independenc

    Diffusion-induced Ramsey narrowing

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    A novel form of Ramsey narrowing is identified and characterized. For long-lived coherent atomic states coupled by laser fields, the diffusion of atoms in-and-out of the laser beam induces a spectral narrowing of the atomic resonance lineshape. Illustrative experiments and an intuitive analytical model are presented for this diffusion-induced Ramsey narrowing, which occurs commonly in optically-interrogated systems.Comment: 4 pages, 8 figure

    Extraction of ammonia sulfate from mother liquor in methylacrylate production

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    In methylacrylate production liquid wastes containing considerable amounts of sulfuric acid and organic compounds are formed. Neutralization of sulfuric acid and removal of organic compounds from the effluent water are the essential phases of ammonia sulfate preparation. Methods of purifying waste water formed in methylacrylate production are proposed. Waste water purification is performed by oxidation, floatation and extraction. Combining several physical and chemical methods the most perfect purification is attained. By removing organic impurities from waste water high grade ammonia sulfate may be obtained as by-product

    Coherent population trapping resonances with linearly polarized light for all-optical miniature atomic clocks

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    We present a joint theoretical and experimental characterization of the coherent population trapping (CPT) resonance excited on the D1 line of 87Rb atoms by bichromatic linearly polarized laser light. We observe high-contrast transmission resonances (up to 25%), which makes this excitation scheme promising for miniature all-optical atomic clock applications. We also demonstrate cancellation of the first-order light shift by proper choice of the frequencies and relative intensities of the two laser field components. Our theoretical predictions are in good agreement with the experimental results.Comment: 8 pages, 7 figure

    Influence of drying and pretreatment methods on certain parameters of yellow mealworm larvae (Tenebrio molitor)

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    Nowadays alternative protein sources like edible insects are becoming widely used as human food. One of the most popular insect is yellow mealworm (Tenebrio molitor) due to its high nutrition value. However, pretreatment and drying are necessary to increase the food shelf life and the efficiency of its use. Due to this, the purpose of the present work was the determination of influence of pretreatment methods (freezing of larvae for 1 month, freezing for 2 hours, freezing for 1 month followed by defrosting for 2 hours at room temperature, blanching) and drying methods (convection drying at 40 °C and 60 °C, microwave drying) of yellow mealworm on its color (determination of L*, а*, b*, ΔElab, Ch, H, BI), moisture content (gravimetric method), fatty acid composition (determined by gas chromatography with mass spectroscopy) and time of drying (time required to reach constant weight). It was found that all used pretreatment and drying methods had no effect on the fatty acid composition of the larvae. In terms of drying rate and color retention, microwave drying showed better results than convection drying at 40 °C and 60 °C. Meanwhile, convection drying at 40 °C leads to the higher final moisture content of the samples. Among the pretreatment methods, only blanching the larvae samples before drying retained their color better and also accelerated the rate of the convection drying

    Homogeneous singularities inside collapsing wormholes

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    We analyze analytically and numerically the origin of the singularity in the course of the collapse of a wormhole with the exotic scalar field Psi with negative energy density, and with this field Psi together with the ordered magnetic field H. We do this under the simplifying assumptions of the spherical symmetry and that in the vicinity of the singularity the solution of the Einstein equations depends only on one coordinate (the homogeneous approximation). In the framework of these assumptions we found the principal difference between the case of the collapse of the ordinary scalar field Phi with the positive energy density together with an ordered magnetic field H and the collapse of the exotic scalar field Psi together with the magnetic field H. The later case is important for the possible astrophysical manifestation of the wormholes.Comment: 10 pages, 5 figures each of which has a),b),c),and d) sub-figures. To be published in "Physical review. D, Particles, fields, gravitation, and cosmology

    Colchicine for gout

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    Colchicine is a drug that has been known for several millennia, since the days of Ancient Egypt, but has been successfully used to treat gout to this day. The action of colchicine is based on microtubule damage, mitosis suppression, as well as the ability to inhibit the activation of NLRP3 inflammasoma by monosodium urate crystals and block the release of interleu-kina (IL)-1p - key cytokine in the development of gout inflammation. However, the mechanism of action of colchicine is still not fully understood.Colchicine should be considered as the optimal drug not only for relieving an acute attack of arthritis in gout, but also as the best method for preventing attacks of gouty arthritis when choosing urate-lowering therapy. Recent studies have confirmed the good efficacy and safety profile of the drug when used correctly in patients with gout. Currently, it is recommended to use low doses of the drug (1-1.5 mg per day to relieve an acute attack of arthritis and 0.5-1.0 mg to prevent attacks when initiating uratelowering therapy). At the same time, according to the results of recent studies on the effectiveness, low doses are not inferior to high doses, but when low doses are used, the frequency of undesirable effects is much less. Unlike non-steroidal anti-inflammatory drugs and glucocorticoids, the drug does not have a negative effect on the cardiovascular system and can be used in patients with diabetes mellitus. This allows the drug to be used for a long time, which is especially important, since it is recommended to prevent arthritis attacks for at least 6 months from the start of taking urate-lowering drugs. This avoids the exacerbation of arthritis in most patients and significantly reduces their frequency. In addition, in the light of the accumulating data on the effect of the drug on the cardiovascular system of the drug, in conjunction with the high safety profile, other points of application should be considered where both anti-inflammatory and cardioprotective properties of colchicine can be used

    Peculiarities of anharmonic lattice dynamics and thermodynamics of alkaline-earth metals

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    The calculations are performed for a broad range of the properties of Ca and Sr in the fcc and bcc phases. A detailed information on the magnitude and character of temperature dependence of anharmonic effects in the lattice dynamics over the entire Brillouin zone (frequency shifts and phonon damping, Gruneisen parameters) is given. A detailed comparison of the computational results for the heat capacity and thermal expansion with the experimental data is carried out; the theoretical results are in good agreement with the experiment.Comment: 16 pages, 19 Postscript figures, Revte
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