194 research outputs found

    The influence of thermoplastic processing on mechanical and relaxation properties of metastable austenitic steel

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    Изучены особенности формирования структуры и механических свойств аустенитных кобальтосодержащих сталей с 1,0 и 5,0 % кобальта при высоких степенях деформации. Кроме того, были изучены механические и релаксационные свойства коррозионно-стойкой стали 03Х14Н11К5М2ЮТ в зависимости от температурно-временных параметров обработки.Features of the formation of the structure and physical and mechanical properties of 1.0 and 5.0% cobalt-containing austenitic steels, at high plastic strains, have been investigated. Mechanical and relaxation properties of corrosion-resistant metastable austenitic steel (03Kh14N11K5M2YuT) have been investigated as function of the pretreatment and the temperature–time treatment conditions.Программа развития УрФУ на 2013 год (п.2.1.2.1

    Heat treatment forming a dissipative metal base in wear-resistant chromium-alloyed cast iron

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    The maximum abrasive wear resistance is provided by a metal base from metastable retained austenite and martensite. Such a microstructure of 260Kh16M2 and 250Kh25MFT chromium cast irons with different types of Cr 7 C 3 and Cr 23 C 6 , carbides is created by high-temperature quenching with heating to temperatures of 1125-1170 °C and cooling in oil or air. Austenite is transformed to disperse martensite on the working surface as a result of the impact of abrasive particles during operation. Together with carbides, it provides a high hardening level and a high working capacity of the secondary microstructure of the cast irons. © 2018 Author(s)

    Projective filtering of a single spatial radiation eigenmode

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    Lossless filtering of a single coherent (Schmidt) mode from spatially multimode radiation is a problem crucial for optics in general and for quantum optics in particular. It becomes especially important in the case of nonclassical light that is fragile to optical losses. An example is bright squeezed vacuum generated via high-gain parametric down conversion or four-wave mixing. Its highly multiphoton and multimode structure offers a huge increase in the information capacity provided that each mode can be addressed separately. However, the nonclassical signature of bright squeezed vacuum, photon-number correlations, are highly susceptible to losses. Here we demonstrate lossless filtering of a single spatial Schmidt mode by projecting the spatial spectrum of bright squeezed vacuum on the eigenmode of a single-mode fiber. Moreover, we show that the first Schmidt mode can be captured by simply maximizing the fiber-coupled intensity. Importantly, the projection operation does not affect the targeted mode and leaves it usable for further applications.Comment: 10 pages, 9 figure

    Spatial entanglement and state engineering via four-photon Hong-Ou-Mandel interference

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    The phenomenon of entanglement is the basis of quantum information and quantum communication processes. Entangled systems with a large number of photons are of great interest at present because they provide a platform for streaming technologies based on photonics. In this paper we present a device which operates with four-photons and based on the Hong-Ou-Mandel (HOM) interference. The presented device allows to maximize the degree of spatial entanglement and generate the highly entangled four-dimensional Bell states. Furthermore, the use of the interferometer in different regimes leads to fast interference fringes in the coincidence probability with period of oscillations twice smaller than the pump wavelength. We have a good agreement between theoretical simulations and experimental results.Comment: 20 pages, 7 figur

    Design and implementation of adaptive technology for teaching mathematics to school children based on integrated diagnostic approach to subject preparation and competence development

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    The development of school teaching  systems to enable effective adaptive communication of information requires specific pedagogical solutions to several important theoretical and methodological problems .These include 1) the discernment of basic characteristics needed to diagnose and improve the quality of subject preparation for schoolchildren, 2) clarifying the role of the teacher in the structure of adaptive learning  process, and  3) finding ways to integrate adaptive content into the framework of courses on mathematics. The purpose of our study was to determine theoretical and methodological foundations of teaching mathematics to schoolchildren taking into account their level of ability with the consequent development of appropriate adaptive content. The basic characteristics that underpin the concept of adaptive learning which contributes to both individual profiles of student ability to learn and subsequent success outcomes are: proficiency, motivation to learn and level of mathematical knowledge. The evaluation of individual profile structure of schoolchildren determines the choice of methodologies for presentation of adaptive content in ways allowing development and motivation. The system of educational process management developed in this way includes both content-methodical and procedural-technological components. This makes it possible to automatically evaluate the level of each students' mathematical training (knowledge, motivation, development) and to ensure continuous improvement. This system can also be used by secondary teachers of mathematics as a part of extracurricular activities, or as a distance learning support. In addition, the recommendations for structuring multi-level problem material can be used by mathematics teachers to self-construct adaptive sets tasks at various stages of teaching mathematics. As a result, students have the opportunity to improve their own profile of learning success, particularly by solving a chain of tasks

    Low-temperature thermal and elastoacoustic properties of butanol glasses: Study of position isomerism effects around the boson peak

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    We have concurrently measured the specific heat, the thermal conductivity, and the longitudinal and transverse sound velocities at low temperature of glasses from different isomers of butanol (n-butanol, sec-butanol and isobutanol), as well as the low-temperature specific heat for the crystals of n-butanol, isobutanol and tert-butanol. Whereas the elastic constants both for crystals and glasses are found to be almost independent of the position of the hydrogen bonds, the thermal properties at low temperatures of these glasses at a few kelvin (around the boson peak in the reduced specific heat or around the plateau in the thermal conductivity) are found to vary strongly. Our experiments clearly contradict other works or models claiming a Debye scaling of the boson peak, and hence of the excess low-temperature specific heat of glasses. Data analysis based upon the soft-potential model and its extensions allows us to estimate the Ioffe-Regel limit in these and other alcohol glasses, finding a correlation with the boson-peak position in agreement with that previously reported by other groupsWe acknowledge financial support by the Spanish Ministry of Science within program CONSOLIDER Nanociencia Molecular CSD2007-00010 and by the Comunidad de Madrid through the project NANOBIOMAGNET S2009/MAT-1726

    Olfactory transport efficiency of the manganese oxide nanoparticles (II) after their single or multiple intranasal administrations

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    In experiments with reusable inhalation of nano-sized metal oxide particles, it has been shown that there is no significant relationship between the number of presentations and the metal concentration in the olfactory bulb. This fact raises the question of a possible decrease in the efficiency of particulate capturing by the olfactory epithelium after their repeated application into the nasal cavity. In this study, we compared the effectiveness of nasal transport of paramagnetic nanoparticles after their single and multiple intranasal administration and evaluated their effects on the morphological and functional characteristics of the olfactory system. Based on the data, the accumulation of MnO-NPs in the olfactory bulb of mice was reduced after repeated intranasal application. In addition, the decrease in the efficiency of olfactory transport observed after repeated administration of MnO-NPs was partially restored by intranasal application of mucolytic (0.01 M N-acetyl-L-cysteine). In this case, the concentration of particles in the olfactory bulb was proportional to the volume of the structure, which in particular depends on the number of synaptic contacts between the mitral cell of the olfactory bulb (OB) and olfactory epithelium (OE). It should be noted that multiple intranasal injections of MnO-NPs reduce mouse OE thickness. Thus, repeated intranasal introduction of MnO-NPs reduces the efficiency of nanoparticle olfactory transport from the nasal cavity to the brain, which is combined with the increase in the viscosity of the mucosal layer and the reduction in the number of synaptic contacts between OB and OE. These results indicate the presence of the natural mechanisms of protection against the penetration of pathogens and xenobiotics into the olfactory epithelium; they also allow us to formulate practical recommendations on intranasal drugs delivery

    Effect of the state of stress on the strain-induced martensite formation in 03Kh14N11K5M2YuT steel

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    The structural changes that occur in a metastable austenitic Fe-Cr-Ni-based steel during cold plastic deformation by drawing and tension are analyzed. A relation between the structure of the steel and its mechanical and magnetic properties is established. It is concluded that the stress state scheme considerably affects the rate of martensite formation. © 2013 Pleiades Publishing, Ltd
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