Взрывные процессы на катоде при формировании наносекундного импульсного разряда высокого напряжения

The paper is devoted to research of cathode surfaces with different curvature radius (r = 1–8 mm) while forming nanosecond pulsed discharge in dense air. Influence of field and air pressure heterogeneity rate in gas gap on size of micro-craters being formed on working cathode surface after pulsed effect has been shown in the paper. The paper reveals a maximum expansion of separate micro-crater size on cathode surface with small curvature radius.Настоящая статья посвящена исследованиям поверхности катодов с различным радиусом кривизны (r = 1–8 мм) при формировании импульсных разрядов наносекундной длительности в плотном воздухе. Показано влияние степени неоднородности поля и давления воздуха в газовом промежутке на размеры микрократеров, образующихся на рабочей поверхности электрода после импульсного воздействия. Выявлено наибольшее увеличение размеров отдельных микрократеров на поверхности катода с малым радиусом кривизны

Explosive Processes on Cathode while Forming Nanosecond Pulsed Discharge of High Pressure

The paper is devoted to research of cathode surfaces with different curvature radius (r = 1–8 mm) while forming nanosecond pulsed discharge in dense air. Influence of field and air pressure heterogeneity rate in gas gap on size of micro-craters being formed on working cathode surface after pulsed effect has been shown in the paper. The paper reveals a maximum expansion of separate micro-crater size on cathode surface with small curvature radius

Methods of Improving Superconductive Fault Current Limiting Devices in Power Engineering (Retracted Article)

Superconducting fault current limiter is a fundamentally new type of device that has no direct analogue among the traditional electrical equipments. The basis of most of its variety, subject to intensive research in the world, is based on the principle of transition-temperature superconductors in the resistive (normal) condition when the current extended, flowing through the superconducting fault current limiter, above defined value. The problem of scaling on superconducting power of current-limiting transformer-type device has been investigated. Opportunities of increasing nominal power of such device based on experiments and calculations have been proposed

Microscopic mechanism of ferroelectric properties in barium hexaferrites

The microscopic mechanism of the occurrence of ferroelectric properties in M-type barium hexaferrites is investigated by experimental and first-principle computation methods. The analysis of magnetic, X-ray, and Mössbauer measurements of BaFe12O19 samples ascertains the correlation between the thermal factor in the process of annealing samples and their functional properties. The occurrence of the remnant polarization in barium hexaferrites at room temperature contradicts the description of their crystal structure in the framework of centrosymmetric space group P63∕mmc (No. 194), in which one of the symmetry operations is inversion center. Therefore, the crystal structure of BaFe12O19 was analyzed in the frameworks of SG P63∕mmc (No. 194) and non-centrosymmetric SG P63mc (No. 186). The computed value of polarization for a non-centrosymmetric unit cell is ∼ 3.5 μC∕cm2. The analysis of polarization was carried out on a path connecting the polar P63mc and non-polar P63∕mmc structures and considered in terms of the total energy barrier. Our result allows ascertaining a direct relationship between the remnant polarization of the unit cell and the broken spatial-inversion symmetry in the crystal structure of M-type barium hexaferrite.This project has received funding from the EU - H2020 research and innovation programme under grant agreement No 654360 having benefitted from the access provided by CSIC/ICMAB in Barcelona (ES) within the framework of the Nanoscience Foundries and Fine Analysis (NFFA: ID 1026) Europe Transnational Access Activity. (European grants to support the infrastructure of European centres of collective usage and mobile activity of researchers). Alex V. Trukhanov thanks NUST MISIS for support within the framework of the “Priority 2030″ (K6-2022-043). The authors thank to Dr. D.B. Migas for help with calculations of initial crystal structures.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).N

ATLAS

% ATLAS \\ \\ ATLAS is a general-purpose experiment for recording proton-proton collisions at LHC. The ATLAS collaboration consists of 144 participating institutions (June 1998) with more than 1750~physicists and engineers (700 from non-Member States). The detector design has been optimized to cover the largest possible range of LHC physics: searches for Higgs bosons and alternative schemes for the spontaneous symmetry-breaking mechanism; searches for supersymmetric particles, new gauge bosons, leptoquarks, and quark and lepton compositeness indicating extensions to the Standard Model and new physics beyond it; studies of the origin of CP violation via high-precision measurements of CP-violating B-decays; high-precision measurements of the third quark family such as the top-quark mass and decay properties, rare decays of B-hadrons, spectroscopy of rare B-hadrons, and $B ^0 _{s}$-mixing. \\ \\The ATLAS dectector, shown in the Figure includes an inner tracking detector inside a 2~T~solenoid providing an axial field, electromagnetic and hadronic calorimeters outside the solenoid and in the forward regions, and barrel and end-cap air-core-toroid muon spectrometers. The precision measurements for photons, electrons, muons and hadrons, and identification of photons, electrons, muons, $\tau$-leptons and b-quark jets are performed over $| \eta |$ < 2.5. The complete hadronic energy measurement extends over $| \eta |$ < 4.7. \\ \\The inner tracking detector consists of straw drift tubes interleaved with transition radiators for robust pattern recognition and electron identification, and several layers of semiconductor strip and pixel detectors providing high-precision space points. \\ \\The e.m. calorimeter is a lead-Liquid Argon sampling calorimeter with an integrated preshower detector and a presampler layer immediately behind the cryostat wall for energy recovery. The end-cap hadronic calorimeters also use Liquid Argon technology, with copper absorber plates. The end-cap cryostats house the e.m., hadronic and forward calorimeters (tungsten-Liquid Argon sampling). The barrel hadronic calorimeter is an iron-scintillating tile sampling calorimeter with longitudinal tile geometry. \\ \\Air-core toroids are used for the muon spectrometer. Eight superconducting coils with warm voussoirs are used in the barrel region complemented with superconducting end-cap toroids in the forward regions. The toroids will be instrumented with Monitored Drift Tubes (Cathode Strip Chambers at large rapidity where there are high radiation levels). The muon trigger and second coordinate measurement for muon tracks are provide