Observation of the fine structure for rovibronic spectral lines in visible part of emission spectra of D2D_2

For the first time in visible part of the $D_2$ emission spectrum the pseudo doublets representing partly resolved fine structure of rovibronic lines have been observed. They are characterized by splitting values about 0.2 cm$^{-1}$ and relative intensity of the doublet components close to 2.0. It is shown that they are determined by triplet splitting in lower rovibronic levels of various $^3\Lambda_g^\pm \to c^3\Pi_u^-$ electronic transitions. It is proposed to use an existence of such partly resolved fine structure patterns for identification of numerous unassigned spectral lines of the $D_2$ molecule coming from great variety of triplet "gerade" electronic states to vibro-rotational levels of the $c^3\Pi_u^-$ state.Comment: 6 pages, including 2 figures and 1 table; submitted to Phys.Rev.Let

Modeling of Metallurgical Process of Copper Fire Refining

The refining of blister copper is based on the partial removal of impurities that have an increased affinity for oxygen. The most interesting is the process of centralized copper refining at one plant. This is because blister copper from the producer plants has a different chemical composition. Obviously, the batch of each loading also has a variable chemical composition. Therefore, for a constantly changing averageweighted composition of a liquid metal, a different amount of oxygen is required to oxidize and slag the impurities. The aim of the work is the method of creating a mathematical model for solving the single-criterion and multicriteria task of firerefining of copper. Algorithms of the model based on the passive experiment are presented, with the chosen assumptions and limitations. Mathematical models are developed using correlation regression analysis. The resultant variable in the models is the concentration of oxygen in the melt. The objective function is determined by the main variables of the refining process. The results of mathematical modeling allow us to quickly calculate the concentration of oxygen supplied in the air composition into the melt of a batch of different chemical composition for the oxidation of impurities. The models are consistent with the general theory of anode melting, and can be used to control and predict the process. Keywords: fire refining, blister copper, impurity oxidation, mathematical model, linear regressio

Qutrit state engineering with biphotons

The novel experimental realization of three-level optical quantum systems is presented. We use the polarization state of biphotons to generate a specific sequence of states that are used in the extended version of BB84 protocol. We experimentally verify the orthogonality of the basis states and demonstrate the ability to easily switch between them. The tomography procedure is employed to reconstruct the density matrices of generated states.Comment: 5 pages, 4 figures. typos correcte

Time turnover of species in bird communities: the role of landscape diversity and climate change

The challenge of searching for patterns of species turnover dynamics in communities of living organisms is directly related to solving problems of stability and functioning of ecosystems. Avian communities are an essential structural and functional component of terrestrial and aquatic ecosystems which are highly diverse and play an important role in a wide range of ecosystem functions. The issue of changes in the dynamics of amphibiotic landscape complexes, where terrestrial and aquatic ecosystems conjugate, is practically not solved. In this connection, a study was carried out within a landscape system, which presents terrestrial and aquatic ecosystems that were in different degrees of anthropogenic transformation. The dynamics of bird communities was considered in the context of recent global climate change. The investigation was conducted in the landscapes of the south and south-east of Ukraine in the nesting seasons 1988–2018. Within the landscape system associated with the Molochny estuary, the ten most important types of ecosystems were distinguished, which included : agricultural lands, artificial forest belts, meadows, islands and spits, reed beds, urban areas, solonchaks, steppe, cliffs, artificial forests. The temporal turnover of the bird communities was decomposed into two parts: the first term (D1) related to the amount of change in community composition, and the second term (D2) being dependent only on the amount of change in community size sensu its abundance. The contribution ratio of the species and of the environment variable were calculated to identify drivers that influence the turnover measure. The average annual temperature and the sum of annual temperatures were considered as environment variables. The bird metacommunity of the studied landscape system was represented by 132 species from 86 genera, 42 families and 13 orders. During the research period the average annual temperature varied from 9.5 to 12.5 ˚C. and the temperature dynamics were subject to the linear trend. An oscillatory component was also present in the temperature dynamics. The annual rainfall ranged 220–761 mm. A coherent change in precipitation and temperature was observed in the period until 2011. After that, the temperature growth stabilized and the amount of precipitation began to fall sharply. The steppe bird community was represented by an extremely small number of species, but demonstrated the ability to maintain a stable structure for a long time. The main fluctuations of the community were quantitative changes in abundance, while the turnover of species was practically absent. Species of the community replace each other cyclically, but there were no targeted changes in community structure. Temperature and precipitation were the main drivers of the bird community in the steppe. The bird communities on salt marshes were characterized by a stable abundance, but a constant directed turnover of species. Reduced water levels and the disappearance of islands in the salt marshes increased the risk of threats from predators, which could lead to a decrease in the abundance of some species. The islands and spits were characterized by high species turnover with quasi-cyclical population dynamics. The main feature of the community dynamics was a decrease in the role of precipitation and an increase in the role of the time factor. The role of temperature remained stably low. The species richness of bird communities in agrarian lands was higher than in steppe communities. The turnover measure was significant because of the increased abundance of Alauda arvensis. Over time, the role of precipitation in the community dynamics has been decreasing and the role of time has been increasing. The value of temperature varied, but was at a stationary level. The turnover of species was compensated by an increase in the abundance of bird communities. The obtained results are in line with findings indicating that despite more stable land use intensities in recent years, climate change has not overtaken land use intensities as the main driver of bird population dynamics

Модель балансування паралельної обробки фото- відеокадрів в обчислювальному кластері для БПЛА

In solving some problems that are common to the system of operating UAVs, for example, parallelprocessing tasks of photo and video-frames, it seems appropriate the operative design of the computing cluster for UAV. The computing cluster for UAV is characterized by a dynamic structure(field) telecommunication system. This circumstance makes it necessary, for management purposes, tosynthesize such model of the cluster what allows, on the one hand, to calculate the effective plan forthe organization of the computation process, and on the other hand - to spend on these calculationsthe minimum resources (particularly - time). It is proposed, in the case of cluster for UAV, the classic,with criteria "cost - performance", (linear) V.Leontyev’s model. Figs:2. Refs:3 titles.При решении некоторых проблем, общих для системы действующих БПЛА, например задач параллельной обработки фото и видеокадров, представляется целесообразным оперативное проектирование вычислительного кластера для БПЛА. Вычислительный кластер для БПЛА характеризуется динамической структурой (полевой) телекоммуникационной системы. Это обстоятельство делает необходимым, для целей управления, синтезировать такую модель кластера, которая позволяет, с одной стороны, вычислить эффективный план организации вычислительного процесса, а с другой - затратить на эти вычисления минимальные ресурсы (вчастности - время). Предлагается, в случае кластера для БПЛА, модель в терминах «стоимость - производительность» на основе (линейной) модели В. Леонтьева. Рис.2. Библиогр.:3назв.При розв’язанні деяких проблем, загальних для системи діючих БПЛА, наприклад завданьпаралельної обробки фото і відео кадрів, представляється доцільним оперативне проектування обчислювального кластера для БПЛА. Обчислювальний кластер для БПЛА характеризується динамічною структурою (польової) телекомунікаційної системи. Ця обставина робить необхідним для цілей управління синтезувати таку модель кластера, яка дозволяє,з одного боку, обчислити ефективний план організації обчислювального процесу, а з іншого -витратити на ці обчислення мінімальні ресурси (зокрема - час). Пропонується, у випадку кластера для БПЛА, класична модель за критерієм «вартість - продуктивність» на основі(лінійної) моделі В. Леонтьєва. Рис.2. Бібліогр.:3 наз

Microscopic description of the beta delayed deuteron emission from \bbox{^6}He

The beta delayed deuteron emission from $^6$He is studied in a dynamical microscopic cluster model. This model gives a reasonably good description for all the subsystems of $^6$He and $^6$Li in a coherent way, without any free parameter. The beta decay transition probability to the $^6$Li ground state is underestimated by a few percents. The theoretical beta delayed deuteron spectrum is close to experiment but it is also underestimated by about a factor 1.7. We argue that, in spite of their different magnitudes, both underestimations might have a common origin. The model confirms that the neutron halo part of the $^6$He wave function plays a crucial role in quenching the beta decay toward the $\alpha$ + d channel.Comment: LATEX with REVTEX, Submitted to Phys. Rev. C, 11 pages, 3 figures (not included) are available upon request. ATOMKI-93/

Ferromagnetic Wires Composite Media with Tunable Scattering Spectra at Microwaves

We demonstrate composite media with ferromagnetic wires that exhibit a frequency region at the microwave regime with scattering spectra strongly dependent on an external magnetic field or stress. These tunable composite materials have recently been proposed theoretically; however, no direct experimental verification has been reported. We used composite materials with predominantly oriented CoFeCrSiB glass-coated amorphous wires having large magnetoimpedance at GHz frequencies. The free space measurements of reflection and transmission coefficients were conducted in the frequency range 1-8 GHz in the presence of an external static magnetic field or stress applied to the whole sample. In general, the transmission spectra show greater changes in the range of 10dB for a relatively small magnetic field of few Oe or stress of 0.1 MPa. The obtained results are quantitatively consistent with the analytical expressions predicted by the effective medium arguments. The incident electromagnetic wave induces an electrical dipole moment in each wire, the aggregate of which forms the effective dipole response of the whole composite structure in the radiative near or far field region. The field and stress dependences of the effective response arise from a field or tensile stress sensitivity of the ac surface impedance of a ferromagnetic wire. In the vicinity of the antenna resonance the variations in the magneto-impedance of the wire inclusions result in large changes of the total effective response. A number of applications of proposed materials is discussed including the field tunable microwave surfaces and the self-sensing media for the remote non-destructive evaluation of structural materials

Influence of tungsten nanoparticles on microstructure and mechanical properties of an Al-5%Mg alloy produced by casting

This paper investigates the impact of tungsten nanoparticles on the microstructure and mechanical properties of the Al-5Mg alloy. Tungsten concentrations of up to 0.5 wt.% led to a slight modification of the Al-5Mg alloy microstructure, and grain refinement occurred due to the inhibition of crystal growth along the boundaries. Dispersion hardening with tungsten nanoparticles made it possible to increase the ultimate strength by the Orowan mechanism with a simultaneous increase in the plasticity of the Al-5Mg alloy. An increase in the tungsten content to 0.8 wt.% made it possible to modify the microstructure of the Al-5Mg alloy, due to the formation of the Al12W phase and an increase in crystallisation centres. The modification of the microstructure, as well as dispersion strengthening by nanoparticles, led to a simultaneous increase in the yield strength, ultimate tensile strength, and ductility of the Al-5Mg alloy

Experimental time-resolved photoemission and ab initio study of lifetimes of excited electrons in Mo and Rh

We have studied the relaxation dynamics of optically excited electrons in molybdenum and rhodium by means of time resolved two-photon photoemission spectroscopy (TR-2PPE) and ab initio electron self-energy calculations performed within the GW and GW+T approximations. Both theoretical approaches reproduce qualitatively the experimentally observed trends and differences in the lifetimes of excited electrons in molybdenum and rhodium. For excitation energies exceeding the Fermi energy by more than 1 eV, the GW+T theory yields lifetimes in quantitative agreement with the experimental results. As one of the relevant mechanisms causing different excited state lifetime in Mo and Rh we identify the occupation of the 4d bands. An increasing occupation of the 4d bands results in an efficient decrease of the lifetime even for rather small excitation energies of a few 100 meV.Comment: 8 pages, 10 figure