A device for automatic diagnostication of analog electric control devices based industrial controller Logo

Запропоновано структуру та програму функціонування мікропроцесорного пристрою діагностування автоматичних аналогових керуючих пристроїв електропривода на базі промислового контролера LOGO.Предложено структуру и программу функционирования микропроцессорного устройства диагностирования автоматических аналоговых управляющих устройств электропривода на базе промышленного контроллера LOGO.The structure and operation of analog electric control devices microprocessor unit program automatic diagnosis based industrial controller LOGO

Pseudo-Goldstone magnons in the frustrated S=3/2 Heisenberg helimagnet ZnCr2Se4 with a pyrochlore magnetic sublattice

Low-energy spin excitations in any long-range ordered magnetic system in the absence of magnetocrystalline anisotropy are gapless Goldstone modes emanating from the ordering wave vectors. In helimagnets, these modes hybridize into the so-called helimagnon excitations. Here we employ neutron spectroscopy supported by theoretical calculations to investigate the magnetic excitation spectrum of the isotropic Heisenberg helimagnet ZnCr2Se4 with a cubic spinel structure, in which spin-3/2 magnetic Cr3+ ions are arranged in a geometrically frustrated pyrochlore sublattice. Apart from the conventional Goldstone mode emanating from the (0 0 q) ordering vector, low-energy magnetic excitations in the single-domain proper-screw spiral phase show soft helimagnon modes with a small energy gap of ~0.17 meV, emerging from two orthogonal wave vectors (q 0 0) and (0 q 0) where no magnetic Bragg peaks are present. We term them pseudo-Goldstone magnons, as they appear gapless within linear spin-wave theory and only acquire a finite gap due to higher-order quantum-fluctuation corrections. Our results are likely universal for a broad class of symmetric helimagnets, opening up a new way of studying weak magnon-magnon interactions with accessible spectroscopic methods.Comment: V3: Final version to be published in Phys. Rev.

Magnonic Weyl states in Cu2OSeO3

The multiferroic ferrimagnet Cu$_2$OSeO$_3$ with a chiral crystal structure attracted a lot of recent attention due to the emergence of magnetic skyrmion order in this material. Here, the topological properties of its magnon excitations are systematically investigated by linear spin-wave theory and inelastic neutron scattering. When considering Heisenberg exchange interactions only, two degenerate Weyl magnon nodes with topological charges $\pm$2 are observed at high-symmetry points. Each Weyl point splits into two as the symmetry of the system is further reduced by including into consideration the nearest-neighbor Dzyaloshinsky-Moriya interaction, crucial for obtaining an accurate fit to the experimental spin-wave spectrum. The predicted topological properties are verified by surface state and Chern number analysis. Additionally, we predict that a measurable thermal Hall conductivity can be associated with the emergence of the Weyl points, the position of which can be tuned by changing the crystal symmetry of the material

Magnetic-field dependence of low-energy magnons, anisotropic heat conduction, and spontaneous relaxation of magnetic domains in the cubic helimagnet ZnCr2Se4

Anisotropic low-temperature properties of the cubic spinel helimagnet ZnCr2Se4 in the single-domain spin-spiral state are investigated by a combination of neutron scattering, thermal conductivity, ultrasound velocity, and dilatometry measurements. In an applied magnetic field, neutron spectroscopy shows a complex and nonmonotonic evolution of the spin-wave spectrum across the quantum-critical point that separates the spin-spiral phase from the field-polarized ferromagnetic phase at high fields. A tiny spin gap of the pseudo-Goldstone magnon mode, observed at wave vectors that are structurally equivalent but orthogonal to the propagation vector of the spin helix, vanishes at this quantum critical point, restoring the cubic symmetry in the magnetic subsystem. The anisotropy imposed by the spin helix has only a minor influence on the lattice structure and sound velocity but has a much stronger effect on the heat conductivities measured parallel and perpendicular to the magnetic propagation vector. The thermal transport is anisotropic at T < 2 K, highly sensitive to an external magnetic field, and likely results directly from magnonic heat conduction. We also report long-time thermal relaxation phenomena, revealed by capacitive dilatometry, which are due to magnetic domain motion related to the destruction of the single-domain magnetic state, initially stabilized in the sample by the application and removal of magnetic field. Our results can be generalized to a broad class of helimagnetic materials in which a discrete lattice symmetry is spontaneously broken by the magnetic order.Comment: 13 pages, 8 figures + Supplemental Materia

Теорія та практика менеджменту безпеки

У збірнику подано тези доповідей та виступів учасників Міжнародної науково-практичної конференції, присвяченої питанням теорії менеджменту безпеки, безпеки особистості, прикладним аспектам забезпечення соціальної, екологічної, економічної безпеки підприємств, питанням механізму забезпечення соціоекологоекономічної безпеки регіону, проблемам забезпечення національної безпеки

Досвід використання інфікованої грибами рослинної сировини як субстрату для мікробного паливного елементу

Article presents the results of experimental investigation applicability of plant fallen materials contaminated by powdery mildew fungus E. flexuosa as substrate in microbial fuel cell (MFC). MCFs were presented in form of Winogradsky’s column. The measurements of generated voltage were carried out in MFCs with different composition during 5 weeks.В статье представлены результаты экспериментального исследования возможности применения контаминированного возбудителем мучнистой росы E. flexuosa листовой опад каштана в качестве субстрата для микробного топливного элемента (МТЭ). МТЭ разрабатывали по принципу колонки Виноградского. Проводили измерения напряжения в течение 5 недель инкубации МТЭ различного компонентного состава.У статті наведено результати експериментального дослідження можливості застосування контамінованого збудником борошнистої роси E. flexuosa листового опаду каштана в якості субстрату для мікробного паливного елементу (МПЕ). МПЕ розробляли за принципом колонки Виноградського. Проводили вимірювання напруги упродовж 5 тижнів інкубування МПЕ різного компонентного складу

Understanding the foreign policy of autocratic actors: ideology or pragmatism? Russia and the Tymoshenko trial as a case study

While the literature on the autocratic regimes has been rapidly growing in the last years, there still exists a research gap in this field: which impact do autocratic regimes have on the regime transition in the neighbouring countries? The literature on autocracies has demonstrated that autocratic political leaders tend to support each other. This article argues that the external influence of an autocracy may be more complex. The article analyses the case of Russia's international standing in relation to the trial of Yulia Tymoshenko. Using detailed process tracing, it has been shown that in terms of the Russian position, pragmatic goals may undermine ideological goals. Thus, while the main objective of Russia is to ensure the stability of gas contracts, the unintended consequences of its actions undermine the consolidation of autocratic regime in Ukraine. The article builds on the literature on regime transition, autocracy, and international relations