794 research outputs found

    Optical and electronic properties of low-density InAs/InP quantum dot-like structures devoted to single-photon emitters at telecom wavelengths

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    Due to their band-structure and optical properties, InAs/InP quantum dots (QDs) constitute a promising system for single-photon generation at third telecom window of silica fibers and for applications in quantum communication networks. However, obtaining the necessary low in-plane density of emitters remains a challenge. Such structures are also still less explored than their InAs/GaAs counterparts regarding optical properties of confined carriers. Here, we report on the growth via metal-organic vapor phase epitaxy and investigation of low-density InAs/InP QD-like structures, emitting in the range of 1.2-1.7 μ{\mu}m, which includes the S, C, and L bands of the third optical window. We observe multiple photoluminescence (PL) peaks originating from flat QDs with height of small integer numbers of material monolayers. Temperature-dependent PL reveals redistribution of carriers between families of QDs. Via time-resolved PL, we obtain radiative lifetimes nearly independent of emission energy in contrast to previous reports on InAs/InP QDs, which we attribute to strongly height-dependent electron-hole correlations. Additionally, we observe neutral and charged exciton emission from spatially isolated emitters. Using the 8-band k{\cdot}p model and configuration-interaction method, we successfully reproduce energies of emission lines, the dispersion of exciton lifetimes, carrier activation energies, as well as the biexciton binding energy, which allows for a detailed and comprehensive analysis of the underlying physics.Comment: 13 pages, 9 figure

    Thermobaric synthesis, structure, and properties of Dy x Cu 3V4O12

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    The perovskite-like compound Dy x Cu3V 4O12 (x = 0.67-0.75) is synthesized under high pressure (P = 4.0-9.0 GPa) and temperature (T = 1000 C). Its crystal structure is determined (Im-3 space group, Z = 2, a = 7.29348(7) Å) by means of powder X-ray diffraction. The basic lengths and bond angles are defined. It is found that the high-pressure phase of Dy x Cu3V 4O12 is characterized by metallic conductivity and paramagnetic properties. © 2013 Allerton Press, Inc

    Investigation of interaction femtosecond laser pulses with skin and eyes mathematical model

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    We present a mathematical model of linear and nonlinear processes that takes place under the action of femtosecond laser radiation on the cutaneous covering. The study is carried out and the analytical solution of the set of equations describing the dynamics of the electron and atomic subsystems and investigated the processes of linear and nonlinear interaction of femtosecond laser pulses in the vitreous of the human eye, revealed the dependence of the pulse duration on the retina of the duration of the input pulse and found the value of the radiation power density, in which there is a self-focusing is obtained. The results of the work can be used to determine the maximum acceptable energy, generated by femtosecond laser systems, and to develop Russian laser safety standards for femtosecond laser systems

    Optimization of Nanostructuring Burnishing Technological Parameters by Taguchi Method

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    On the basis of application of Taguchi optimization method, an approach for researching influence of nanostructuring burnishing technological parameters, considering the surface layer microhardness criterion, is developed. Optimal values of burnishing force, feed and number of tool passes for hardened steel AISI 420 hardening treatment are defined

    Tensor analyzing power Ayy in deuteron inclusive breakup at large Pt and spin structure of deuteron at short internucleonic distances

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    The Ayy data for deuteron inclusive breakup off hydrogen and carbon at a deuteron momentum of 9.0 GeV/c and large Pt of emitted protons are presented. The large values of Ayy independent of the target mass reflect the sensitivity of the data to the deuteron spin structure. The data obtained at fixed xx and plotted versus Pt clearly demonstrate the dependence of the deuteron spin structure at short internucleonic distances on two variables. The data are compared with the calculations using Paris, CD-Bonn and Karmanov's deuteron wave functions.Comment: 4 pages, 2 figures, talk given at the SPIN2004 Conf., 10-16 Oct. 2004, Triest, Ital

    Two ideals connected with strong right upper porosity at a point

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    Let SPSP be the set of upper strongly porous at 00 subsets of R+\mathbb R^{+} and let I^(SP)\hat I(SP) be the intersection of maximal ideals ISPI \subseteq SP. Some characteristic properties of sets EI^(SP)E\in\hat I(SP) are obtained. It is shown that the ideal generated by the so-called completely strongly porous at 00 subsets of R+\mathbb R^{+} is a proper subideal of I^(SP).\hat I(SP).Comment: 18 page

    Tensor Ayy and vector Ay analyzing powers in the H(d,d')X and ^{12}C(d,d')X reactons at initial deuteron momenta of 9 GeV/c in the region of baryonic resonances excitation

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    The angular dependence of the tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen and carbon have been measured. The range of measurements corresponds to the baryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being in good agreement with the previous results demonstrate an approximate tt scaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role of the spin-dependent part of the elementary amplitude of the NN->NN* reaction. The results of the experiment are compared with model predictions of the plane-wave impulse approximation.Comment: 7 pages, 7 figures. submitted to Yad.Fi

    Architectural and Spiritual Monuments of the City in the Fate of Human

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    The article presents the biography of the architect and restorer, Anatoly Andreyevich Kuzmin, who devoted his whole life to preserving the spiritual heritage of the city of Nizhny Tagil – temple buildings. The story is told by the artist's granddaughter.В статье представлена биография архитектора и реставратора Анатолия Андреевича Кузьмина, посвятившего всю жизнь сохранению духовного наследия города Нижнего Тагила – храмовым постройкам. История рассказана внучкой художника

    Optimization of Nanostructuring Burnishing Technological Parameters by Taguchi Method

    Get PDF
    On the basis of application of Taguchi optimization method, an approach for researching influence of nanostructuring burnishing technological parameters, considering the surface layer microhardness criterion, is developed. Optimal values of burnishing force, feed and number of tool passes for hardened steel AISI 420 hardening treatment are defined
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