A spherical model with directional interactions: I. Static properties

We introduce a simple spherical model whose structural properties are similar to the ones generated by models with directional interactions, by employing a binary mixture of large and small hard spheres, with a square-well attraction acting only between particles of different size. The small particles provide the bonds between the large ones. With a proper choice of the interaction parameters, as well as of the relative concentration of the two species, it is possible to control the effective valence. Here we focus on a specific choice of the parameters which favors tetrahedral ordering and study the equilibrium static properties of the system in a large window of densities and temperatures. Upon lowering the temperature we observe a progressive increase in local order, accompanied by the formation of a four-coordinated network of bonds. Three different density regions are observed: at low density the system phase separates into a gas and a liquid phase; at intermediate densities a network of fully bonded particles develops; at high densities -- due to the competition between excluded volume and attractive interactions -- the system forms a defective network. The very same behavior has been previously observed in numerical studies of non-spherical models for molecular liquids, such as water, and in models of patchy colloidal particles. Differently from these models, theoretical treatments devised for spherical potentials, e.g. integral equations and ideal mode coupling theory for the glass transition can be applied in the present case, opening the way for a deeper understanding of the thermodynamic and dynamic behavior of low valence molecules and particles.Comment: 11 pages, 11 figure

Peculiarities of polyneuropathy in the peripheral t-cell lymphoma with cytostatics

This paper presents data on the occurrence and form of polyneuropathy in the peripheral T-cell lymphoma, and its main pathogenesis elements. Here the toxic effects of cytotoxic drugs and their role in the impairment of the nervous system have been describe

On the Definition of Effective Permittivity and Permeability For Thin Composite Layers

The problem of definition of effective material parameters (permittivity and permeability) for composite layers containing only one-two parallel arrays of complex-shaped inclusions is discussed. Such structures are of high importance for the design of novel metamaterials, where the realizable layers quite often have only one or two layers of particles across the sample thickness. Effective parameters which describe the averaged induced polarizations are introduced. As an explicit example, we develop an analytical model suitable for calculation of the effective material parameters $\epsilon_{\rm{eff}}$ and $\mu_{\rm{eff}}$ for double arrays of electrically small electrically polarizable scatterers. Electric and magnetic dipole moments induced in the structure and the corresponding reflection and transmission coefficients are calculated using the local field approach for the normal plane-wave incidence, and effective parameters are introduced through the averaged fields and polarizations. In the absence of losses both material parameters are purely real and satisfy the Kramers-Kronig relations and the second law of thermodynamics. We compare the analytical results to the simulated and experimental results available in the literature. The physical meaning of the introduced parameters is discussed in detail.Comment: 6 pages, 5 figure

Pulse-driven near-resonant quantum adiabatic dynamics: lifting of quasi-degeneracy

We study the quantum dynamics of a two-level system driven by a pulse that starts near-resonant for small amplitudes, yielding nonadiabatic evolution, and induces an adiabatic evolution for larger amplitudes. This problem is analyzed in terms of lifting of degeneracy for rising amplitudes. It is solved exactly for the case of linear and exponential rising. Approximate solutions are given in the case of power law rising. This allows us to determine approximative formulas for the lineshape of resonant excitation by various forms of pulses such as truncated trig-pulses. We also analyze and explain the various superpositions of states that can be obtained by the Half Stark Chirped Rapid Adiabatic Passage (Half-SCRAP) process.Comment: 21 pages, 12 figure

Agrobiological assessment of productivity and nitrogen fixation of vegetable soybean (edamame) in the conditions of Forest-Steppe of Ukraine

Received: May 25th, 2023 ; Accepted: October 18th, 2023 ; Published: October 30th, 2023 ; Correspondence: [email protected] evaluation of vegetable soybean cultivars (Glycine max var. Shirofumi) according to a complex of economically valuable traits for introduction in the conditions of the Forest-Steppe of Ukraine it was carried out with the aim of selecting the source material and selecting promising breeding forms according to morpho-biological and physiologicalbiochemical characteristics. The research was conducted in the conditions of the educational and production department of Uman National University of Horticulture during 2020–2022, collection cultivars of different ecological and geographical origins were used. The cultivars ‘Sac’ (166.00 g plant-1 ), ‘Vesta’ (139.33 g plant-1 ), ‘Fiskeby V’ (133.33 g plant-1 ), and ‘Fiskeby V-E5’ (146.67 g plant-1 ) possessed a large mass of edamame beans. The maximum yield of edamame beans was formed by plants of the ‘L 380-2-13’ (12.67 t ha-1 ), ‘Vesta’ (12.33 t ha-1 ), ‘Sac’ (13.20 t ha-1 ), ‘Fiskeby V’ (13.97 t ha-1 ), and ‘Fiskeby V-E5’ (14.53 t ha-1 ). Weather conditions during the period of research significantly influenced the yield and biochemical composition of edamame varieties. The yield of edamame beans ranged from 5.40 t ha-1 in 2020 (min) to 22.40 t ha-1 in 2021 (max), and the coefficient of variation by varieties was at the level of 19–41%. This phenomenon is explained by the minimum amount of precipitation in 2020 and the high amount in 2021, which is confirmed by the hydrothermal coefficient during the period of intensive pod growth (VII–VIII) - 2020 - 0.3; 2021 - 1.3 and 1.1 respectively for the month. The protein concentration in Edamame beans was in the range of 27.94–36.29%. A higher protein content relative to the standard was noted in one sample - ‘Karikachi’ - 36.29%. Minimal accumulation of oligosaccharides was noted in ‘Sac’ and ‘Astra’ cultivars, which indicates their suitability for consumption. Promising cultivars were identified by the amount of fixed nitrogen - ‘Sac’ (168.00 ± 4.32 kg ha-1 ), ‘Astra’ (161.67 ± 2.36 kg ha-1 ) and SybNYYSOH 6 (158.19 ± 4.56 kg ha-1 ). The conducted regression analysis showed close relationships (from moderate to functional) between various indicators of the development and productivity of the nodulation apparatus of edamame cultivars. The evaluation of the collection cultivars of vegetable soybeans, their use according to the variability of morphological features and productivity made it possible to single out the ‘Sac’ among the introduced collection cultivars based on a set of valuable traits for use in the selection process to create new cultivars of vegetable soybeans

Chaos assisted adiabatic passage

We study the exact dynamics underlying stimulated Raman adiabatic passage (STIRAP) for a particle in a multi-level anharmonic system (the infinite square-well) driven by two sequential laser pulses, each with constant carrier frequency. In phase space regions where the laser pulses create chaos, the particle can be transferred coherently into energy states different from those predicted by traditional STIRAP. It appears that a transition to chaos can provide a new tool to control the outcome of STIRAP

On the topology of adiabatic passage

We examine the topology of eigenenergy surfaces characterizing the population transfer processes based on adiabatic passage. We show that this topology is the essential feature for the analysis of the population transfers and the prediction of its final result. We reinterpret diverse known processes, such as stimulated Raman adiabatic passage (STIRAP), frequency-chirped adiabatic passage and Stark-chirped rapid adiabatic passage (SCRAP). Moreover, using this picture, we display new related possibilities of transfer. In particular, we show that we can selectively control the level which will be populated in STIRAP process in Lambda or V systems by the choice of the peak amplitudes or the pulse sequence

Modes and the alpha-gamma transition in rf capacitive discharges in N2O at different rf frequencies

This paper reports current-voltage characteristics and pressure-voltage transition curves from the weak-current a-mode to the strong-current g-mode for rf capacitive discharges in N2O at frequencies of 2 MHz, 13.56 MHz, and 27.12 MHz. At 2 MHz the rf discharge is mostly resistive whereas at 13.56 MHz and 27.12 MHz it is mostly capacitive. The weak-current a-mode was found to exist only above a certain minimum gas pressure for all frequencies studied [N. Yatsenko Sov. Phys. Tech. Phys. 26, 678 (19810] previously proposed that the a−g transition corresponds to breakdown of the sheaths. However, we show that this is the case only for sufficiently high gas pressures. At lower pressure there is a smooth transition from the weak-current a-mode to a strong-current g-mode, in which the sheaths produce fast electrons but the sheath has not undergone breakdown

The influence of amino acids on the activity of antioxidant enzimes, malonic dialdehyde content and productivity of garlic (Allium Sativum L.)

The research was carried out in 2017–2019 in the conditions of the Right-Bank Forest Steppe of Ukraine. The results of study, the effect of spraying by certain amino acids; salicylic(300 ppm), gibberellin (150 ppm) and ascorbic acids (200 ppm) on garlic (Allium sativum L.) plants are presented in the article. It was found that amino acid solutions improves the antioxidant state: the activities of SOD, CAT, POD, GR, GST in treated leaves tended to increase, the activity of SOD was higher than the control of 7.5–15.0%; CAT (27.4–45.9%); POD (7.0–83.0%); GR (5.4–49.9%); and GST (14.8–41.3%). It was noted that the content of chlorophyll a+b in the leaves significantly increased (2.6–10.8%), The use of amino acids increased the accumulation of dry matter by 1.4–4.0%. The yield increase was 1.14–2.27 t ha-1 (7.7–15.3% compared to control). The content of B vitamins in the garlic cloves was greatly influenced by gibberellic acid, where increasing the amount of B vitamins reached to 21.9% relative to control The use of salicylic and ascorbic acids increased the amount of B vitamins by 7.6 and 8.2%, respectively. The most significant increasing of C vitamin content was observed by spraying of plants with ascorbic acid (+12.5%), whereas by spraying with salicylic and gibberellic acids its content increased by 6.0 and 7.5%, respectively. In the future, the data obtained can be used to reduce the impact of abiotic factors on the physiological state and productivity of garlic plants. Also, the obtained data will serve as a theoretical basis for producers in view of the purposes for which the products are grown (for sale in fresh form, processing or storage)