Architecture of economic activity efficiency of agricultural fruit producers of the region under sanctions

In the current realities, it is engineering and dealer services that take into account the balance of interests to ensure the development of management decisions that contribute to improving the quality of activities of fruit growing organizations in the region, the effective use of engineering innovations and equity capital. During the study, an assessment was made of entrepreneurial activity, the duration of the operating and financial cycles, financial stability of engineering and dealer organizations, and a factor analysis of return on capital was carried out, using the example of manufacturers of agricultural machinery for fruit growing. The assessment of indicators included an assessment of turnover of current assets, profitability, SWOT analysis and identification of risks of reducing the efficiency of business activities, taking into account factors affecting the optimization of leverage. Low profitability of the engineering and dealer business is associated with an ineffective pricing strategy, setting low prices when participating in government contracts and a significant amount of variable costs in the overall cost structure. To improve the situation, it was proposed to optimize the work of dealer centers and revise the pricing policy

Photoluminescent properties of oxidized stochiometric and carbon-rich amorphous Si₁₋xCx:H films

Near-stochiometric and carbon-rich a-Si₁₋xCx:H thin films were deposited using the magnetron sputtering of Si target in Ar/CH₄ gas mixture. As-deposited nearstochimetric (x = 0.5) sample showed weak blue photoluminescence (PL), while PL of as-deposited carbon-rich (x = 0.7) sample was 20 times stronger and white in color. The films were annealed in pure argon, wet argon, and dry oxygen at 450 °C for 30 min. The intensity of PL in a-Si₁₋xCx:H layers were enhanced by the factor from 2 to 12 after annealing in dependence on the annealing atmosphere. The strongest oxidation and strongest light emission were observed in carbon-rich series (x = 0.7) after annealing in oxidizing atmosphere. Structural properties of the films were characterized by infra-red absorption spectroscopy, ellipsometry and electron paramagnetic resonance. The effect of carbon enrichment of a-Si₁₋xCx:H films and annealing atmosphere on the evolution of photoluminescence and local interatomic bonding structure in annealed material were studied and analyzed. It has been found that main effects of thermal treatments is strong enhancement of photoluminescence accompanied by formation of Si:C–Hn and Si–OxCy bonding. The strongest oxidation effect as well as strongest hotoluminescence were observed in carbon-rich a-SiC:H films

Ultrafast insulator-metal transition in VO2 nanostructures assisted by picosecond strain pulses

Strain engineering is a powerful technology that exploits the stationary external or internal stress of specific spatial distribution for controlling the fundamental properties of condensed materials and nanostructures. This advanced technique modulates in space the carrier density and mobility, the optical absorption, and in strongly correlated systems, the phase, e.g., insulator-metal or ferromagnetic-paramagnetic. However, while successfully accessing nanometer-length scales, strain engineering is yet to be brought down to ultrafast time scales allowing strain-assisted control of the state of matter at THz frequencies. We demonstrate control of an optically-driven insulator-to-metal phase transition by a picosecond strain pulse, which paves the way to ultrafast strain engineering in nanostructures with phase transitions. This is realized by simultaneous excitation of VO2 nanohillocks by a 170-fs laser and picosecond strain pulses finely timed with each other. By monitoring the transient optical reflectivity of the VO2, we show that strain pulses, depending on the sign of the strain at the moment of optical excitation, increase or decrease the fraction of VO2 that undergoes an ultrafast phase transition. A transient strain of moderate amplitude of approximately 0.1% applied during ultrafast photo-induced nonthermal transition changes the fraction of VO2 in the laser-induced phase by approximately 1%. In contrast, if applied after the photoexcitation when the phase transformations of the material are governed by thermal processes, a transient strain of the same amplitude produces no measurable effect on the phase state

Study of gams and related turbulent particle flux with hibp in the T-10 tokamak

The new findings in the behavior of geodesic acoustic modes (GAMs) and turbulent particle flux dynamics on the T-10 tokamak are presented. For the first time in T-10 the broadband oscillations ( 0.8, the dominated GAM peak with frequency ~ 14 kHz and noticeable peak of quasi-coherent oscillations in the frequency band 40…100 kHz were observed. The multichannel HIBP measurements were performed to measure poloidal electric field Epol and to retrieve the electrostatic turbulent radial particle flux driven by E×B drift. The preliminary experiment shows that in contrast to the power spectral density of plasma potentials, GAM peak was almost invisible in the Epol power spectrum and on the frequency resolved turbulent particle flux. These results are consistent with the general concept of GAM as a high-frequency branch of zonal flows, having symmetric poloidal structure of potential perturbation, which were supported by earlier observation of poloidal mode number m=0 in T-10.Представлены новые результаты исследований геодезических акустических мод (ГАМ) и турбулентного потока частиц на токамаке T-10. Впервые на Т-10 в разрядах с омическим и ЭЦР-нагревом (Bt = 1,6…2,4 Tл, Ipl = 0,15…0,3 MA, n‾e = (0.6…5)×10¹⁹ m⁻³) в горячей зоне плазмы с помощью зондирования пучком тяжёлых ионов (ЗПТИ) измерены широкополосные колебания электрического потенциала и плотности с частотами до 250 кГц. На периферии, r/a > 0,8, наблюдался преобладающий пик ГАМ с частотой ~ 14 кГц и заметный пик квазикогерентных колебаний с частотами 40…100 кГц. Многоканальные ЗПТИ измерения позволили оценить полоидальное электрическое поле Epol и найти радиальный электростатический турбулентный поток частиц, возбуждаемый E×B дрейфом. Предварительные эксперименты показали, что ГАМ пик виден на спектре колебаний потенциала, но практически не виден на спектре Epolи на частотно разрешённом потоке частиц. Эти результаты согласуются с общей теоретической концепцией, что ГАМ – это высокочастотная ветвь зональных потоков с симметричной полоидальной структурой возмущений потенциала, а также с прежними наблюдениями полоидального модового числа m = 0.Представлено нові результати досліджень геодезичних акустичних мод (ГАМ) і турбулентного потоку часток на токамаці T-10. Вперше на Т-10 в розрядах з омічним і ЕЦР-нагрівом (Bt = 1,6…2,4 Tл, Ipl = 0,15...0,3 MA, n‾e = (0.6…5)×10¹⁹ m⁻³) у гарячій зоні плазми за допомогою зондування пучком важких іонів (ЗПВІ) виміряні широкосмугові коливання електричного потенціалу та щільності з частотами до 250 кГц. На периферії, r/a > 0,8, спостерігався переважаючий пік ГАМ з частотою ~ 14 кГц і помітний пік квазікогерентних коливань з частотами 40…100 кГц. Багатоканальні ЗПВІ виміри дозволили оцінити полоїдальне електричне поле Epol і знайти радіальний електростатичний турбулентний потік часток, збуджуваний E×B дрейфом. Попередні експерименти показали, що ГАМ пік видно на спектрі коливань потенціалу, але практично не видно на спектрі Epol і на частотно дозволеному потоці часток. Ці результати узгоджуються із загальною теоретичною концепцією, що ГАМ - це високочастотна гілка зональних потоків з симетричною полоїдальною структурою обурень потенціалу, а також з колишніми спостереженнями полоїдального модового числа m = 0

Multiband light emission and nanoscale chemical analyses of carbonized fumed silica

Fumed silica with a specific area of 295 m(2)/g was carbonized by successive phenyltrimethoxysilane treatments followed by annealing in inert atmosphere up to 650 degrees C. Emission, excitation, kinetics, and photo-induced bleaching effects were investigated by steady state and time-resolved photoluminescence spectroscopies. The local chemistry was also studied by infrared transmission spectroscopy. Strong ultraviolet and visible photoluminescence was observed in the samples after the chemical treatments/modifications and thermal annealing. It has been shown that ultraviolet photoluminescence in chemically modified fumed silica is associated with phenyl groups, while near ultraviolet and visible emission in annealed samples originated from inorganic pyrolytic carbon precipitates dispersed in the silica host matrix. Two types of emission bands were identified as a function of the annealing temperature: one is in the near UV and the other is in the visible range. Based on the emission/excitation analysis of these two bands, as well as on correlations with the synthesis conditions, a structural-energy concept of light-emitting centers has been proposed. According to this model, the light-emitting centers are associated with carbon clusters that can be bonded or adsorbed on the silica surface. This has been validated by a detailed (S)TEM-electron energy-loss spectroscopy study, confirming the inhomogeneous distribution of nanoscale carbon precipitates at the surface of the silica nanoparticles. These carbon precipitates are mostly amorphous although they possess some degree of graphitization and local order. Finally, the fraction of sp(2) carbon in these nanoclusters has been estimated to be close to 80%. Published by AIP Publishing

Study of poloidal structure of geodesic acoustic modes in the T-10 tokamak with heavy ion beam probing

The poloidal structure of geodesic acoustic modes (GAMs) was studied on the T-10 tokamak by heavy ion beam probing with multichannel energy analyzer. GAMs were mainly pronounced on the plasma electric potential. The poloidal phase shift between the potential oscillations was determined by the two-point correlation technique. It was shown that GAM potential oscillations have the poloidal mode number m=0 in the core plasma. This experimental result agrees with theoretical predictions.На токамаке T-10 с помощью пучка тяжелых ионов исследована полоидальная структура геодезических акустических мод (ГАМ), которые явно видны на потенциале плазмы. Фазовый сдвиг между колебаниями потенциала определялся методом двухточечной корреляции с помощью многоканального энергетического анализатора. Показано, что ГАМ на потенциале имеют полоидальное модовое число m=0. Этот экспериментальный результат согласуется с теоретическими предсказаниями.На токамаці T-10 за допомогою пучка важких іонів досліджена полоїдальна структура геодезичних акустичних мод (ГАМ), що явно видно на потенціалі плазми. Фазове зміщення між коливаннями потенціалу визначається методом двохточечної кореляції за допомогою багатоканального енергетичного аналізатора. Показано, що ГАМ на потенціалі мають полоїдальное модове число m=0. Цей експериментальний результат узгоджується з теоретичними передбаченнями

Graphene layers fabricated from the Ni/a-SiC bilayer precursor

This paper considers a synthesis of graphene flakes on the Ni surface by vacuum long and nitrogen rapid thermal treatment of the “sandwich” amorphous (a) SiC/Ni multilayer deposited on silicon wafer by magnetron sputtering technique. The lateral size of graphene flakes was estimated to be about hundreds of micrometers while the thickness estimated using Raman scattering varied from one to few layers in case of vacuum annealing. Rapid thermal annealing (RTA) in nitrogen ambient results in formation of multilayer graphene with surface covering up to 80%. The graphene layers synthesized on Ni during CVD process was used as reference samples. Atomic force microscopy (AFM) is not able to detect graphene flakes in regime of surface topology examination because of large roughness of Ni surface. Employment of scanning Kelvin probe force microscopy (SKPFM) demonstrates correlation of the surface potential and graphene flakes visible in optical microscopy. Using the KPFM method, potential differences between Ni and graphene were determined

Study of the Process e+e−→KL0KS0e^+e^- \to K^0_L K^0_S in the C.M.Energy Range 1.05-1.38 GeV with CMD-2

The process $e^+e^- \to K^0_L K^0_S$ has been studied with the CMD-2 detector using about 950 events detected in the center-of-mass energy range from 1.05 to 1.38 GeV. The cross section exceeds the expectation based on the contributions of the rho(770), omega(782) and phi(1020) mesons only.Comment: 12 pages, 3 figures, uses elsart.cls, submitted to Physics Letters

Electroluminescent properties of Tb-doped carbon-enriched silicon oxide

An electroluminescent device utilizing a heterostructure of amorphous terbium doped carbon-rich SiOx (a - SiOx : C : Tb) on silicon has been developed. The a - SiOx : C : Tb active layer was formed by RF magnetron sputtering of a - SiO₁₋x : Cx : H(:Tb) film followed by high-temperature oxidation. It was shown that, depending on the polarity of the applied voltage, the electroluminescence is either green or white, which can be attributed to different mechanisms of current transport through the oxide film – space charge limited bipolar double injection current for green electroluminescence and trap assisted tunneling or Fowler-Nordheim tunneling for white electroluminescence

Modeling of some nonstationary processes in tokamak plasmas

The results of modeling of shots from two series of experiments in two tokamaks with rather different geometric parameters are presented. The first one includes two shots from the spherical tokamak MAST with current ramp up, and the second one, a number of T-10 shots with periodic gas puffing. The modeling was performed with the ASTRA code in the framework of Canonical Profiles Transport Model (CPTM).Представлены результаты моделирования импульсов из двух серий экспериментов на двух разных токамаках, существенно отличающихся геометрическими параметрами. Первая серия включает два импульса с нарастанием тока сферического токамака MAST, а вторая – несколько импульсов Т-10 с периодическим газонапуском. Моделирование осуществлялось с помощью кода ASTRA в рамках транспортной модели канонических профилей (ТМКП).Представлені результати моделювання імпульсів з двох серій експериментів на двох різних токамаках, що істотно відрізняються геометричними параметрами. Перша серія включає два імпульси з наростанням струму сферичного токамака МАST, а друга – декілька імпульсів Т-10 з періодичним газонапуском. Моделювання здійснювалося за допомогою коду ASTRA в рамках транспортної моделі канонічних профілів (ТМКП)