277 research outputs found
Method for loading cargo trucks using two-dimensional packing algorithms
The paper describes the method for optimization of loading cargo trucks using two-dimensional packing algorithms. The point of this method is to reduce loading cargo problem to two-dimensional packing problem. This problem can be solved by using of various algorithms. There is analysis of several algorithms that are most often used in practical calculations of objects distribution in 2D space in this paper. The object of this study is transport of the metal processing company and its products (cargo). PHP programming language, MySQL database, and Apache web server are used to create client application. The interface developed using HTML5, CSS and javascript. © 2019 IOP Publishing Ltd. All rights reserved.The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006
Systems to Control Molten Metal Transfer in Arc Welding
The paper analyzes the systems used for controlling molten wire metal droplets during the arc welding process in shielding gases. The variations for implementing the relevant systems are given, with the positive and negative aspects of such implementation taken into account. Electrical systems are currently investigated to the fullest extent possible and implemented in different power sources for pulsed welding arc. Mechanical systems are represented by different types of feeders that provide the pulsed wire feeding process. The feed mechanisms driven by electric motors and electromagnets are analyzed. In addition to the mechanical and electrical systems, the examples of combined control systems are given
Absence of bound states for waveguides in 2D periodic structures
We study a Helmholtz-type spectral problem in a two-dimensional medium
consisting of a fully periodic background structure and a perturbation in form
of a line defect. The defect is aligned along one of the coordinate axes,
periodic in that direction (with the same periodicity as the background), and
bounded in the other direction. This setting models a so-called "soft-wall"
waveguide problem. We show that there are no bound states, i.e., the spectrum
of the operator under study contains no point spectrum.Comment: This is an updated version of our paper (in slightly different form
in Journal of Mathematical Physics). An anonymous reviewer kindly made us
aware that ref. 10 is not applicable in our situation. An application of the
theorem in ref. 10 would have proved the absence of singular continuous
spectrum also. Our result on the absence of point spectrum is not affected by
thi
The Remilitarization of World Politics in the Context of National Security of Modern Russia
The article considers the problems of ensuring international and national security in the twenty-first century. The authors examine the impact of the remilitarization on international relations in the post-bipolar world. Is determined by the nature of the policy change the military-political expansionism of world powers in the conditions of development of globalization processes. The authors conclude that the specificity of the remilitarization of the era of globalization is that this phenomenon becomes transnational, and planetary in scale. The conclusion about the relevance develop priorities for countering the politics of militarism in international relations in the context of the common security space. The necessity of formulating a set of measures aimed at preventing challenges, dangers and threats to the national interests of modern Russia, the source of which is the remilitarization of international politics
Nonlinear interaction of meta-atoms through optical coupling
We propose and experimentally demonstrate a multi-frequency nonlinear coupling mechanism between split-ring resonators. We engineer the coupling between two microwave resonators through optical interaction, whilst suppressing the direct electromagnetic coupling. This allows for a power-dependent interaction between the otherwise independent resonators, opening interesting opportunities to address applications in signal processing, filtering, directional coupling, and electromagnetic compatibility.This work was supported by the
Ministry of Education and Science of Russian Federation
(Project No. 11.G34.31.0020), Russian Foundation for Basic
Research (Projects No. 13-02-00411 and 14-02-31783),
Scholarship of the President of the Russian Federation for
young scientists and graduate students, and by the Australian
Research Council (CUDOS Centre of Excellence
CE110001018). A.P.S. acknowledges the support of SPIE
Scholarship 2012-2013 and the IEEE MTT-S Undergraduate
Scholarship for spring 2013. A.P.S. and D.S.F. are also
grateful to the “Dynasty” Foundation (Russia)
On semiclassical dispersion relations of Harper-like operators
We describe some semiclassical spectral properties of Harper-like operators,
i.e. of one-dimensional quantum Hamiltonians periodic in both momentum and
position. The spectral region corresponding to the separatrices of the
classical Hamiltonian is studied for the case of integer flux. We derive
asymptotic formula for the dispersion relations, the width of bands and gaps,
and show how geometric characteristics and the absence of symmetries of the
Hamiltonian influence the form of the energy bands.Comment: 13 pages, 8 figures; final version, to appear in J. Phys. A (2004
Effects of hydrogen on trap neutralization in BaSi2 with interstitial silicon atoms
Semiconducting barium disilicide (BaSi2) is one of emerging materials for solar cell applications. Therefore, defect neutralization is very important for improving its solar cell performance. Herein, the effect of atomic hydrogen (H) on the photoresponsivity of 500-nm-thick undoped n-BaSi2 films grown under Si-rich conditions by molecular beam epitaxy was examined, wherein interstitial Si atoms were likely to exist instead of common Si vacancies. The photoresponsivity reached a maximum of ∼1.3 A W−1 at room temperature (about twice as large as that for as-grown films) in BaSi2 films exposed to an atomic H for 10 s. This H treatment time is much smaller than that for BaSi2 films grown under stoichiometric conditions, indicating that interstitial Si atoms provide a smaller trap concentration with respect to the case of Si vacancy domination and incorporation of H atom can neutralize traps. The inverse logarithmic slope (E0) of the Urbach tail was investigated to discuss the dependence of the photoresponsivity of BaSi2 films on H treatment time. There was a clear negative correlation between E0 and photocurrent density obtained from the photoresponsivity. The detailed picture on how interstitial Si atoms affect the electronic structure of BaSi2 by defect state formation and how H atom incorporation modifies the structure is revealed by ab initio calculations that allowed interpreting and understanding of all experimentally observed trends
Effects of bipolarons on oxidation states, and the electronic and optical properties of W18O49
W18O49 has been studied by means of ab initio techniques in the framework of the density functional theory using the onsite Hubbard-U correction applied to the W-d states as well as using the hybrid potential. The existence of bipolarons is found to be an intrinsic feature of this oxide resulting in the presence of different oxidation states of W atoms (W6+ and W5+) and in the co-existence of localized and delocalized electrons. We also discuss possible switching from the W6+ to W5+ and from the W5+ to W4+ oxidation states in the presence of an O vacancy. It appears that O vacancy formation does not cause any additional charge localization at W sites but solely contributes to delocalized electrons. The calculated absorption and reflection coefficients manifest a transparency window in the visible region. At the same time, sizable absorption, occurring due to the presence of free carriers, is detected in the far and mid infrared regions. Additionally, in the near infrared region we confirm and explain an experimentally observed shielding effect originating from transitions involving the localized bipolaronic states
Orientation and size effects on phonon thermal conductivity in silicon/germanium multilayer structures
We study the effect of morphology on the in- and cross-plane phonon thermal conductivity of the (001), (110), and (111) oriented Si/Ge multilayer films by means of non-equilibrium molecular dynamics at 300 K. The extended comparison of the estimated values for the multilayer films to one for the appropriate homogeneous Si and Ge films has been performed. The results revealed a significant advantage in reducing the thermal
conductivity of the Si/Ge multilayer films compared to the referenced homogeneous Ge and Si films for the cross-plane transport regardless of the film orientation, and for the in-plane transport only for (001)/[¯
110 ,] (110)/[001] directions with an increase in the number of periods, which indicated the prospects of such layered structures
- …