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  • A Lightweight Modified YOLO Network for Road Scene Object Detection

    The paper considers a lightweight modified version of the YOLO-v5 neural network, which is used to recognize road scene objects in the task of controlling an unmanned vehicle. In the proposed model, the pooling layer is replaced by the ADown module in order to reduce the complexity of the model. The C2f module is added as a feature extraction module to improve accuracy by combining features. Experiments using snowy road scenes are presented and the effectiveness of the proposed model for object recognition is demonstrated.

    Keywords: road scene object recognition, YOLOv5, Adown, C2f, deep learning, pooling layer, neural network, lightweight network, dataset

  • Determination of the atomic structure of bimetallic Pt-Ag nanoparticles in metal-carbon catalysts by X-ray absorption spectroscopy data

    The atomic structure of bimetallic nanoparticles of Pt-Ag composition, which are the part of metal-carbon electro-catalysts PtAg/C, is studied by means of EXAFS spectroscopy using the suggested technique. These materials have been prepared by methods of consistent and simultaneous deposition of Ag and Pt atoms from aqueous ethylene glycol solutions of their salts with subsequent acid treatment. The values ​​of the structural parameters of the near environment of platinum atoms are determined. The nature of the distribution of components in nanoparticles is established. Cluster models of nanoparticles are constructed. The fraction of Pt atoms in the working shell and its dependance on preparation methods in each case are determined.

    Keywords: Metal-carbon electrocatalysts, bimetallic nanoparticles, Catalysis, Platinum, X-ray absorption spectroscopy, atomic structure

  • Mathematical model of straining of orthotropic conical shells

    The article presents a mathematical model of deformation of thin-walled conical shells, considering orthotropic material, geometric nonlinearity and transverse shear. Showing geometric relationships, physical relationships, the functional of total energy of deformation and boundary conditions.

    Keywords: conical shell, tapered panel, mathematical model, geometric nonlinearity, orthotropic, lateral shifts

  • Synthesis and electrochemical characteristics of the new composite cathode material of LiMn2O4@LiCoO2 for lithium-ion battery

    The composite cathode material of the core@shell type with the LiMn2O4@LiCoO2 formula of has been successfully synthesized using the solid-state reactions in several stages. Its structure has been studied by means of X-ray diffraction, scanning and transmission electron microscopy and vibrational infrared spectroscopy. Electrochemical investigation in two-electrode cell has been showed improvement of characteristics of the synthesized cathode material than the constituent components. The specific power of LiMn2O4@LiCoO2 is 650 mWh/g, against 450 and 500 mWh/g for LiCoO2 and LiMn2O4, respectively.

    Keywords: lithium-ion batteries, cathode materials, Delafosse, X-ray structural analysis, electron microscopy, electrochemical properties

  • Local Atomic and Electronic Structure of the Fe dopants in AlN:Fe Nanorods

    Fe-doped AlN nanorods were studied by means of x-ray absorption spectroscopy above the Fe K- and L2,3- edges. Theoretical simulations of the x-ray absorption spectra show that Fe atoms mainly substitute Al. A minor fraction of Fe interstitials or Fe-Al-N ternary alloy can be identified as well. Bader’s AIM analysis predicts that neutral substitutional FeAl defect is in 2+ charge state, though Al in pure AlN is in 3+ charge state.  Fe L2,3 absorption spectra and photoluminescence data indicate the coexistence of Fe2+/Fe3+ in AlN:Fe nanorods so different charge states of substitutional FeAl should co-exist.

    Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production

  • Comparative study of the catalytic activity Pt/C and PtхNi/C materials in the oxygen electroreduction

    The catalytic activity of Pt/C and PtxNi/C electrocatalysts prepared by  borohydride methode was studed. It was established that the specific activity  of fresh prepared Pt3,7Ni/C  catalyst  in oxygen  electroreduction  reaction is higher in compare with Pt/C material. After treatment of Pt3,7Ni/C material in the hot acid  nickel in the surface layers of nanoparticles was dissolved and the composition of nanoparticles was changed to Pt5,6Ni. The electrochemical surface area of the Pt5,6Ni catalyst and specific activity was slightly decreased after corrosion treatment. 

    Keywords: platinum electrocatalysts, corrosion stability of the nanoparticles, fuel cells, X-ray diffraction, borohydride synthesis

  • UV photodetector based on nanorods and zinc oxide films

    With the use of pulsed laser deposition and carbothermal synthesis а photosensitive structure on the basis of the Schottky barrier Au/ZnO(nanorods)/ZnO(film)/ZnO(nanorods)/Au was obtained. The parameters of the carbothermal method of synthesis of nanorods ZnO were optimized. Under directly applied bias of 7V current sensitivity of luminous flux for this photodetector is observed in the UV and visible regions of the spectrum, and is 0.14 A/W - for 325 nm and 0.18 A/W - to 405 nm, which means that this structure has the ability of potential applications in various fields for the control of UV radiation (for example, for the monitoring of solar UV radiation, control of UV radiation in air and disinfecting water devices).

    Keywords: ZnO nanorods, Schottky barrier, photodetector, photosensitivity

  • Pulsed laser deposition of ZnO nanostructures

    The arrays of ZnO nanorods were obtained on the sapphire substrates by means of pulsed laser deposition under the high pressure of argon. The conditions of synthesis were optimized, and their influence on the morphology of  ZnO nanostructures were revealed. It is shown that the concentration of oxygen vacancies in ZnO nanorods can be changed by regulation of the synthesis temperature from 850 to 915 °. This process can be controlled by the ratio of intensities of the photoluminescence emission in the visible and ultraviolet regions. So, it allows to create nanostructures for UV photodetectors or chemosensors depending on the temperature choice.

    Keywords: ZnO nanorods, laser deposition, PLD, photoluminescence

  • The method of functionally integrated laser-modulators design

    The proposed method of designing hardware components optical switching systems simplifies prototyping and development of systems of optical switching and multi-core VLSI. This method allows to automatically set parameters of the optical system at the design stage, depending on the requirements. This method may be cost-effective at the stage of technical specifications of the project, as will reduce the time required for its coordination between the customer and the design engineer.
    At the heart of developing a method of designing systems, optical switching elements is a comprehensive analysis of the equations and functions describing the electrical and optical properties of laser heterostructures, as well as electro-optic modulators and Fabry-Perrot resonators. Fundamental static and dynamic characteristics of semiconductor diode lasers can be calculated by using a set of kinetic equations describing the interaction of electrons, holes and photons in the active layer of the laser structure. At various stages of this method is processing, evaluation and calculation of the main characteristics of the elements of integrated optical switching systems.  

    Keywords: optical switching, integrated injection laser, quantum-scale heterostructure, amplitude modulation, terahertz range

  • Technique of microinjection in axons of nerve cells, surrounded by dense glial sheath, using ultrasound vibration of microcapillary

    Intracellular microinjection - a method of direct introduction of cellular organelles and solutions of substances into living cells. The technique of microinjection into nerve cells by puncturing their processes - axons , which are often surrounded by a dense glial sheath, are described. To puncture the sheath a special injector transmitting microvibrations of ultrasonic frequency on the injection capillary was designed. The results of using the proposed microinjection technique for introducing fluorescent marker in large axons of model object - crayfish ventral nerve cord, to visualize the morphology of axons, were shown.

    Keywords: intracellular microinjection, neuron, axon, glial sheath, ultrasound vibration, piezoelectric transducer

  • Software tools and biological databases for building hypothesis on protein-protein interactions after proteomics profiling

    The authors suggest two approaches to constructing hypotheses about the interactions of proteins on the basis of the results of tracking the changes in their levels during the studied biological process. The first approach is based on the use of machine mining of biological texts, which are freely available on the Internet. The second is related to the execution of database queries on binary protein-protein interactions . To specify the experimental context in obtained protein networks, filtering of the protein entities on the basis of needed ontology from database Gene Ontology was used.

    Keywords: text mining, data base, protein-protein interaction, protein networks

  • Magnetic properties of multiferroics BiFeO3, (BiLa)FeO3 and (BiNd)FeO3 electrets formed by corona discharge

    Recently, BiFeO3  multiferroics have drawn a great deal of attention due to their superior ferroelectric properties in epitaxial thin film form in comparison to counterpart bulk single crystals or ceramics. In this work we present the results on magnetic properties of multiferroic ultrathin films (30-300 nm) of BiFeO3, (BiLa)FeO3 and  (BiNd)FeO3  obtained by sputtering in transverse high frequency discharge, vacuum laser oblation and metalorganic chemical vapour deposition  on monocrystalline  substrates of (001) SrTiO3, (100) MgO and  (100) Al2O3. The concentration of Bi, La и Nd in dodecahedral sublattices was varied. A novel effect of treatment of multiferroic films in a negative corona discharge has been investigated. It is demonstrated that the magnetisation may be increased by up to 35%  whilst the change in    is not noticeable. This effect does not depend on neither film composition no technological method. 

    Keywords: multiferroics, magneto-electric materials, methods of preparation, the films of bismuth ferrite, pseudomorphic structure, magnetic properties, corona discharge

  • Development of elements for "smart clothes" based on the electrochemical charge storage system for microsystems technique

    In this paper we propose basic geometric, mass and electrical parameters of the element for collection of static electricity from the surface of the textile. This element is a reversible electrochemical charge storage system based on nanostructured nickel oxide and carbon cloth. Element has a planar structure, it is flexible, lightweight, safety and ergonomic. Proposed element can be used as a power source for the Microsystems technique in "smart clothes".

    Keywords: "smart clothes", microsystems technique, static electricity, supercapacitor, composite material NiO/C

  • Modeling the ab initio structure of layered aluminosilicates.

    This work deals with the study of atomic and electronic structure of kaolinite samples (Glukhovtsy deposit) and montmorillonite (Millerovsky deposit) by density functional theory. The applicability of existing exchange-correlation potential in the local density approximation (LDA) and the generalized gradient approximation (GGA) is analised for an adequate description of the physical properties of layered aluminosilicate. An experimental and theoretical study of the IR spectra of minerals, as well as the identification of the most intense absorption bands, performed in the approximation of DFT using the exchange-correlation potential PW91. The analysis of the band structure of these minerals, which showed that these compounds are direct-gap insulators.

    Keywords: DFT, clay, clay minerals, phyllosilicates, atomic and electronic structure, crystalline systems, IR spectrum band strukutra, the electron density

  • Development and design of bimorph thermal actuator and а micromirror based on it

    A design of the actuator, consisting of a thin layers of silicon dioxide and aluminum is proposed. There are calculations made of the response speed and heat dissipation of the actuator. By making the best selection of layer thicknesses and optimization stages of technological process, in particular the deep selective etching of silicon, the best performance on the angle of inclination of the actuator and the speed of the device could be achived. The greater the difference between the initial temperature and the heating temperature, the stronger the beam of the actuator is lowered to the plane of the silicon plate, and, therefore, less angle of elevation above the surface of the silicon plate. It is thus possible to control the angle of the beam by selecting the appropriate heater and voltage, providing the desired temperature. The design of the micromirror device based on the proposed actuator is provided. The developed design is based on the actuator and allows for controling the tilt of the mirror in a wide range.

    Keywords: silicon, termoactuator, micromechanical systems, bimorph structure, micromirrors