454 research outputs found
Heusler 4.0: Tunable Materials
Heusler compounds are a large family of binary, ternary and quaternary
compounds that exhibit a wide range of properties of both fundamental and
potential technological interest. The extensive tunability of the Heusler
compounds through chemical substitutions and structural motifs makes the family
especially interesting. In this article we highlight recent major developments
in the field of Heusler compounds and put these in the historical context. The
evolution of the Heusler compounds can be described by four major periods of
research. In the latest period, Heusler 4.0 has led to the observation of a
variety of properties derived from topology that includes: topological metals
with Weyl and Dirac points; a variety of non-collinear spin textures including
the very recent observation of skyrmions at room temperature; and giant
anomalous Hall effects in antiferromagnetic Heuslers with triangular magnetic
structures. Here we give a comprehensive overview of these major achievements
and set research into Heusler materials within the context of recent emerging
trends in condensed matter physics
Heralded quantum steering over a high-loss channel
Entanglement is the key resource for many long-range quantum information
tasks, including secure communication and fundamental tests of quantum physics.
These tasks require robust verification of shared entanglement, but performing
it over long distances is presently technologically intractable because the
loss through an optical fiber or free-space channel opens up a detection
loophole. We design and experimentally demonstrate a scheme that verifies
entanglement in the presence of at least dB of added loss,
equivalent to approximately km of telecommunication fiber. Our protocol
relies on entanglement swapping to herald the presence of a photon after the
lossy channel, enabling event-ready implementation of quantum steering. This
result overcomes the key barrier in device-independent communication under
realistic high-loss scenarios and in the realization of a quantum repeater.Comment: 8 pages, 5 figure
Development of the heat and mass transfer model for the study of the temperature traces water droplets in a flame
The heat and mass transfer model is developed with using Ansys Fluent. The typical temperature of gases in the trace of water droplets is determined (initial temperature of gases 1170 К). Several types for the location of water droplets are studied: two successive water droplets; two parallel water droplets; five water droplets in checkerboard order. The hypothesis about gas temperature reduction in the trace of a moving liquid is confirmed
Исследование и разработка гистерезисных электрических машин на основе деформируемого сплава Fe-Cr-Co
В ходе научно-квалификационной работы исследован материал ротора синхронного гистерезисного двигателя (СГД) из сплава 22Х15КА ГОСТ 24897-81. Получены динамические магнитные характеристики сплава на частотах перемагничивания от 50 Гц до 2 кГц. Представлены результаты исследования СГД в программной среде AnsysMaxwell 2D/3D.In the course of the scientific and qualifying work, the rotor material of the synchronous hysteresis motor from alloy 22Х15КА GOST 24897-81 was investigated. Dynamic magnetic characteristics of the alloy at the magnetization reversal frequencies from 50 Hz to 2 kHz are obtained. The results of the study of a synchronous hysteresis motor in the software environment of AnsysMaxwell 2D / 3D are presented
Cryogenic calorimeters in astro and particle physics
The development of cryogenic calorimeters was originally motivated by the
fact that very low energy thresholds and excellent energy resolutions can be
achieved by these devices. Cryogenic devices are widely used in double beta
decay experiments, in cosmological dark matter searches, in x-ray detection of
galactic and extragalactic objects as well as in cosmic background radiation
experiments. An overview of the latest developments is given.Comment: (28 pages, contribution to the VIII International Conference on
Calorimetry in High Energy Physics, 13-19 June 1999, Lisbon, Portugal
The First 1 1/2 Years of TOTEM Roman Pot Operation at LHC
Since the LHC running season 2010, the TOTEM Roman Pots (RPs) are fully
operational and serve for collecting elastic and diffractive proton-proton
scattering data. Like for other moveable devices approaching the high intensity
LHC beams, a reliable and precise control of the RP position is critical to
machine protection. After a review of the RP movement control and position
interlock system, the crucial task of alignment will be discussed.Comment: 3 pages, 6 figures; 2nd International Particle Accelerator Conference
(IPAC 2011), San Sebastian, Spain; contribution MOPO01
Optical diffraction radiation for position monitoring of charged particle beams
In the framework of the future linear collider collaboration (CLIC, ILC), non-intercepting beam monitoring instruments are under development for very low emittance and high charge density beams. Optical diffraction radiation (ODR) was studied and developed during the last years focussing on beam size measurements. We propose in the paper to consider the use of diffraction radiation for ultra relativistic beams as position monitors with applications for the centering of scrapers, collimators and targets with high resolution. We present the experimental results obtained using small aperture slits on the ATF2 extraction beam line at KEK and on the Cornell Electron Storage Ring with 1.2 GeV and 2.1 GeV electrons respectively
Characterization of the radiation tolerance of cryogenic diodes for the High Luminosity LHC inner triplet circuit
Cryogenic bypass diodes are part of the baseline powering layout for the circuits of the new Nb3Sn based final focus magnets of the high luminosity Large Hadron Collider. They will protect the magnets against excessive transient voltages during a nonuniform quenching process. The diodes are located inside an extension to the magnet cryostat, operated in superfluid helium and exposed to ionizing radiation. Therefore, the radiation tolerance of different types of diodes has been tested at cryogenic temperatures in CERN’s CHARM irradiation test facility during its 2018 run. The forward bias characteristics, the turn-on voltage and the reverse blocking voltage of each diode were measured weekly at 4.2 K and 77 K, as a function of the accumulated radiation dose. The diodes were submitted to a total dose close to 12 kGy and a 1 MeV neutron equivalent fluence of 2.2×1014 cm−2. After the end of the irradiation program the annealing behavior of the diodes was tested by increasing the temperature slowly to 293 K. This paper describes the experimental setup, the measurement procedure and the analysis of the measurements performed during the irradiation program as well as the results of the annealing study
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