1,031 research outputs found
Development of laboratory information management system
Results of the actual direction of work of Scientific Research Institute of HV on development of the program complex LIS/LIMS «Chemist - analysts» for automatization of activity of analytical laboratories are presented. Functions of the complex and methodological principles of its development are considered, comparison with foreign analogues is carried out. The model of the industrial analytical control with use of concepts of a life cycle of a laboratory, technique and test is described
Theory of magnetoelastic resonance in a mono-axial chiral helimagnet
We study magnetoelastic resonance phenomena in a mono-axial chiral helimagnet
belonging to hexagonal crystal class. By computing the spectrum of coupled
elastic wave and spin wave, it is demonstrated how hybridization occurs
depending on their chirality. Specific features of the magnetoelastic resonance
are discussed for the conical phase and the soliton lattice phase stabilized in
the mono-axial chiral helimagnet. The former phase exhibits appreciable
non-reciprocity of the spectrum, the latter is characterized by a
multi-resonance behavior. We propose that the non-reciprocal spin wave around
the forced-ferromagnetic state has potential capability to convert the linearly
polarized elastic wave to circularly polarized one with the chirality opposite
to the spin wave chirality.Comment: 12 pages, 5 figures, Accepted in Phys. Rev.
Conductance oscillations and zero-bias anomaly in a single superconducting junction to a three-dimensional topological insulator
We experimentally investigate Andreev transport through a single junction
between an s-wave indium superconductor and a thick film of a three-dimensional
topological insulator. We study samples with different
bulk and surface characteristics, where the presence of a topological surface
state is confirmed by direct ARPES measurements. All the junctions demonstrate
Andreev transport within the superconducting gap. For junctions with
transparent interfaces we find a number of nearly periodic
conductance oscillations, which are accompanied by zero-bias conductance
anomaly. Both effects disappear above the superconducting transition or for
resistive junctions. We propose a consistent interpretation of both effects as
originating from proximity-induced superconducting correlations within the
topological surface state
Вихрова динаміка сполучених течій
Group constructions of bluff bodies are widely used in bridge construction practice. The junction flows of such structures are characterized by considerable complexity, nonstationarity and instability. In the vicinity of bluff bodies, systems of horseshoe vortex structures, shear layers, separated regions, jet flows, wake vortices and vortex Karman’s streets are formed. The study of the features of the generation and evolution of vortex and jet flows, the mechanisms of interaction of these flows with streamlined surfaces requires considerable effort during numerical and physical modeling. The purpose of the work is to determine the features of vortex and jet flow in the region of junction of three-row pile grillage with a rigid flat surface. Experimental studies were carried out in laboratory conditions in a hydrodynamic channel, where the three-row group of cylinders was installed on the hydraulically smooth rigid surface. Visual investigations and measurements of the velocity field were carried out inside and around the three-row grillage. The features of the formation and evolution of vortex and jet flows inside and near the cylindrical group were established. Integral and spectral characteristics of the velocity fluctuation field were obtained.
Pages of the article in the issue: 25 - 28
Language of the article: UkrainianГрупові конструкції погано обтічних тіл широко використовуються у мостобудівній практиці. Сполучені течії таких конструкцій характеризуються значною складністю, нестаціонарністю та нестійкістю. В околі погано обтічних тіл формуються системи підковоподібних вихрових структур, зсувні шари, відривні області, струменеві течії, слідні вихори та вихрові доріжки Кармана. Мета роботи – визначення особливостей вихрової та струменевої течії в області сполучення трирядного пального ростверку з жорсткою пласкою поверхнею. Проведені експериментальні дослідження в лабораторних умовах за допомогою візуалізації та вимірювання полів швидкості сполученої течії. Визначено механізм генерації та еволюції вихрових і струменевих течій. Отримані інтегральні та спектральні характеристики поля швидкості в околі передньої групи циліндрів трирядного ростверку
Executive Summary: Young people, education, employment and ESOL
The report, ‘Young people, education, employment and ESOL’ reviewed 47 studies1 to examine how current ESOL provision2 meets the needs of young people aged 16-25 years who use English as an Additional Language (EAL)3, and who need time and support to develop their English language skills in order to progress in education, training and employment
VHF scintillations, orientation of the anisotropy of F-region irregularities and direction of plasma convection in the polar cap
Scintillation data recorded at the polar cap station Barentsburg are shown to occasionally exhibit two or more peaks in the latitudinal profiles of the amplitude dispersion. Comparison with concurrent SuperDARN radar convection maps indicates that multiple peaks occur when Barentsburg is located within the area of strong changes in the plasma flow direction. When parameters of the ionospheric irregularities are inferred from the scintillation data, the orientation of the irregularity anisotropy in a plane perpendicular to the magnetic field is found to coincide well with the <I><b>E</b></I>&times;<I><B>B</B></I> flow direction, individually for each peak of the scintillation data. The differences were found to be mostly less than 20&deg; for a data set comprised of 104 events. The conclusion is made that analysis of scintillation data allows one to infer the direction of plasma flow with a certain degree of detail
Orientation of the cross-field anisotropy of small-scale ionospheric irregularities and direction of plasma convection
The relationship between the orientation of the small-scale ionospheric irregularity anisotropy in a plane perpendicular to the geomagnetic field and the direction of plasma convection in the F region is investigated. The cross-field anisotropy of irregularities is obtained by fitting theoretical expectations for the amplitude scintillations of satellite radio signals to the actual measurements. Information on plasma convection was provided by the SuperDARN HF radars. Joint satellite/radar observations in both the auroral zone and the polar cap are considered. It is shown that the irregularity cross-field anisotropy agrees quite well with the direction of plasma convection with the best agreement for events with quasi-stationary convection patterns
Change in the state of an exploited fish population: From individual indicators to integral assessment
We adapted the approach used for the integral assessment of the status of ecosystems in order to assess population status. Classic theoretical concepts of fish population dynamics are the basis of this approach. The convolution of information about changes in several structural and functional characteristics into one integral index was performed using the analytical function of desirability. The index varied 0 to 1 and quantitatively characterizes the state of the population. This approach was tested on the example of the European grayling Thymallus thymallus (Linnaeus, 1758), inhabiting the Vym River (basin of the Northern Dvina River, North of the European part of Russia). The materials were collected during the environmental monitoring carried out by the Institute of Biology of Komi Science Centre of the Ural Branch of the Russian Academy of Sciences (IB FRC Komi SC UB RAS) in 2002, 2005–2019. The population parameters used in the calculations (relative abundance; average and maximum age of fish; the proportion of matured individuals in the 4+ age group; average specific growth rate of fish at the age of 6+; body weight of fish in the age group 6+) were characterized on the basis of the control net catches. Compared with the period 2005–2006, the value of the integral index in 2015–2018 decreased by almost two times. This indicates deterioration in the condition of the grayling group in the study area. There were no serious disturbances in the fish habitat in this area. The main hydrochemical and hydrobiological indicators have not changed significantly. The main reason for the observed changes is likely the significant increase in the impact of recreational anglers. The proposed integral index may be useful both for assessing the state of fish populations and for developing measures for the rational management of fish stocks
GaAs(111)A and B in hydrazine sulfide solutions : extreme polarity dependence of surface adsorption processes
Chemical bonds formed by hydrazine-sulfide treatment of GaAs(111) were
studied by synchrotron photoemission spectroscopy. At the B surface, the top
arsenic atoms are replaced by nitrogen atoms, while GaAs(111)A is covered by
sulfur, also bonded to underlying gallium, despite the sulfide molar
concentration being 103 times smaller than that of the hydrazine. This extreme
dependence on surface polarity is explained by competitive adsorption processes
of HS- and OH- anions and of hydrazine molecules, on Ga- adsorption sites,
which have distinct configurations on the A and B surfaces
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