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Kharkiv, Ukraine

Sergey S.,PhD. NTU Khpi | Dmitriy D.,NTU KhPI
YSF 2015 - International Young Scientists Forum on Applied Physics | Year: 2015

To article describes the experimental study on the nominal varistor voltage 6 - 10 kV, and the results of these studies. It shows the current voltage characteristics of varistors for different manufacturers. The influence of the effect on the current orientation of the varistor voltage characteristic of the arrester and leakage current. Illuminated issues of calculation of leakage current due to the uniqueness of each varistor and a lack of necessary data from the manufacturers. Practical recommendations that were developed the settlements and to select arresters for networks with low quality electric energy. © 2015 IEEE. Source


Sergey S.,PhD. NTU Khpi | Dmitriy D.,NTU KhPI
YSF 2015 - International Young Scientists Forum on Applied Physics | Year: 2015

The aim of the article is to determine, by experiment on large-scale models, the probability of direct lightning strikes in overhead lines with protected wires for different model configurations. The experimental results have allowed to refute the hypothesis of the absence of direct impacts in protected wires of overhead lines. The studies conducted suggest that lightning defeat of overhead lines with protected wires is substantially lower than that traditional lines. © 2015 IEEE. Source


Bovda O.M.,National Science Center Kharkov Institute of Physics and Technology | Bovad V.O.,National Science Center Kharkov Institute of Physics and Technology | Onischenko L.V.,National Science Center Kharkov Institute of Physics and Technology | Tortika O.S.,National Science Center Kharkov Institute of Physics and Technology | And 5 more authors.
Functional Materials | Year: 2013

Effects of La addition on microstructure and magnetic properties of LaxNd33xFe65.9B1.1 (wt. %) melt-spun ribbons and isotropic bonded magnets were systematically studied. X-ray diffraction and DSC data revealed that addition of La led to the formation of highly refined and inhomogeneous La-rich phase. It was shown that the average grain size and volume fraction of the main magnetic (La,Nd)2Fe14B phase depend on La concentration. For better LaxNd33xFe65.9B1.1 x = 2.5 and 5 wt. % bonded samples, the room-temperature magnetic properties of Hcl = 1343 kA/m and 1300 kA/m, and Br = 0.61 T and 0.614 T were obtained. Magnetic flux aging loss for alloys with appropriate La content (x = 5-10 wt. %) did not exceed 5 % in the range of 100-125C, which is typical for conventional ternary Nd-Fe-B melt-spun magnets. © 2013 - STC "Institute for Single Crystals". Source


Semchenko G.D.,NTU KhPI | Panasenko M.A.,NTU KhPI | Zelenskii O.I.,UKhIN | Baklan V.Yu.,I. I. Mechnkov ONU
Refractories and Industrial Ceramics | Year: 2010

Types of carbon nanostructures that are used for synthesizing nanofibers within carbon-graphite materials in order to improve their physicomechanical properties are considered. © 2010 Springer Science+Business Media, Inc. Source


Skatkov L.,PCB Argo | Gomozov V.,NTU KhPI | Bayrachniy B.,NTU KhPI
Journal of Analytical and Applied Pyrolysis | Year: 2012

The cathode of solid metal oxide-semiconductor capacitors is considered as the semiconductor, MnO 2, obtained by means of impregnation of the anode with Mn(NO 3) 2 solutions within pyrolytic decomposition. Stability range of capacitor structure is mainly determined by the amount of water contained by manganese dioxide, which ensure compaction of contacts between capacitors due to packing of cavities in MnO 2, i.e. depends on open porosity of pyrolytic layer. At the same time it is known that the whole range of differently characterized microporous objects display their fractal properties. Taking all this into account the present paper is concerned on investigation of microporosity and fractal properties of pyrolytic MnO 2 films by small-angle X-ray scattering method. It has been determined that the major contribution to the submicropores volume concentration is made by submicropores not exceeding 8 nm. The MnO 2 layers are fractal structures with the value of volume fractal dimension D = 2.87. © 2012 Elsevier B.V. Source

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