We demonstrate, experimentally and theoretically, controlled loading of an exciton-polariton vortex chain into a 1D array of trapping potentials. Switching between two types of vortex chains, with ...topological charges of the same or alternating signs, is achieved by appropriately shaping an off-resonant pump beam that drives the system to the regime of bosonic condensation. In analogy to spin chains, these vortex sequences realize either a "ferromagnetic" or an "antiferromagnetic" order, whereby the role of spin is played by the orbital angular momentum. The ferromagnetic ordering of vortices is associated with the formation of a persistent chiral current. Our results pave the way for the controlled creation of nontrivial distributions of orbital angular momentum and topological order in a periodic exciton-polariton system.
We study, theoretically and numerically, the onset and development of modulational instability in an incoherently pumped spatially homogeneous polariton condensate. Within the framework of mean-field ...theory, we identify regimes of modulational instability in two cases: (1) strong feedback between the condensate and reservoir, which may occur in scalar condensates, and (2) parametric scattering in the presence of polarization splitting in spinor condensates. In both cases we investigate the instability-induced textures in space and time including nonequilibrium dynamics of phase dislocations and vortices. In particular we discuss the mechanism of vortex destabilization and formation of spiraling waves. We also identify the presence of topological defects, which take the form of half-vortex pairs in the spinor case, giving an "eyelet" structure in intensity and dipoletype structure in the spin polarization. In the modulationally stable parameter domains, we observe formation of the phase defects in the process of condensate formation from an initially spatially incoherent low-density state. In analogy to the Kibble-Zurek-type scaling for nonequilibrium phase transitions, we find that the defect density scales with the pumping rate.
The article considers the legislative and regulatory acts that specify the tasks in the implementation of breeding processes. The results of the creation, variety testing, patenting and introduction ...of grape varieties and clones into the State Register of the Russian Federation for 2010-2020 are presented. The article analyzes the relationship between the indicators of industrial development with the production volumes of planting material, the use of domestic varieties that are included in the State Register of the Russian Federation. The characteristic of ampelographic collections - the genetic resources of grapes - is given. A comparative analysis of many years' worth of data on the assessment of the adaptive potential of domestic varieties and introduced varieties is presented. The article describes domestic varieties, from which premium wines are produced, which not only competes with European varieties, but also surpasses the organoleptic properties and biochemical parameters of grape must and wine material. The main problems hindering the wide demand for domestic varieties on the market, including a substantial amount of imported European varietal planting material, are described. The necessity of accelerating breeding processes is actualized, modern methods are identified, including those of generative and genomic selection, transgenic technologies, cellular, mutational, and clone selection, and priority areas in breeding are presented. The numerical and qualitative analyses of the composition of breeding scientists is given, the trends of increasing the number and qualitative composition of breeders, the influx of young people, the growing need for training qualified personnel are noted. The number of bachelor's, master's and post-graduate students specializing in viticulture in general and in selection in particular as well as the number of defended dissertation studies on grape breeding has been found to be insufficient. The main scientific and practical problems in the organization and implementation of breeding processes in ensuring the development of the industry are updated, including a low share of domestic varieties in the produced planting material and planting, the lack of a systemically implemented varietal and technological policy, the imperfection of the legal system for the protection of intellectual property, a low availability of instrumentation and analytical equipment for the implementation of breeding by modern methods.
We demonstrate, experimentally and theoretically, a Talbot effect for hybrid light-matter waves-an exciton-polariton condensate formed in a semiconductor microcavity with embedded quantum wells. The ...characteristic "Talbot carpet" is produced by loading the exciton-polariton condensate into a microstructured one-dimensional periodic array of mesa traps, which creates an array of phase-locked sources for coherent polariton flow in the plane of the quantum wells. The spatial distribution of the Talbot fringes outside the mesas mimics the near-field diffraction of a monochromatic wave on a periodic amplitude and phase grating with the grating period comparable to the wavelength. Despite the lossy nature of the polariton system, the Talbot pattern persists for distances exceeding the size of the mesas by an order of magnitude. Thus, our experiment demonstrates efficient shaping of the two-dimensional flow of coherent exciton polaritons by a one-dimensional "flat lens."
► Three novel antimicrobial peptides were isolated from Taraxacum officinale flowers. ► Primary structures of these peptides were determined and it was shown that their molecules belong to new types ...of cystein-rich plant peptides. ► The peptides of current structure types were discovered only in dandelion flowers. ► The peptides were shown to display high antimicrobial activity both against fungal and bacterial pathogens in laboratory conditions.
Three novel antimicrobial peptides designated ToAMP1, ToAMP2 and ToAMP3 were purified from Taraxacum officinale flowers. Their amino acid sequences were determined. The peptides are cationic and cysteine-rich and consist of 38, 44 and 42 amino acid residues for ToAMP1, ToAMP2 and ToAMP3, respectively. Importantly, according to cysteine motifs, the peptides are representatives of two novel previously unknown families of plant antimicrobial peptides. ToAMP1 and ToAMP2 share high sequence identity and belong to 6-Cys-containing antimicrobial peptides, while ToAMP3 is a member of a distinct 8-Cys family. The peptides were shown to display high antimicrobial activity both against fungal and bacterial pathogens, and therefore represent new promising molecules for biotechnological and medicinal applications.
•Closed fuel cycle is one of the key features developed within the framework of «Proryv» project in Russian Federation.•Equilibrium reactor core is characterized by the stable reactivity isotopic ...composition of recycled plutonium.•Analytical studies have been made on sodium cooled large size reactor (1200 MW).
Equilibrium reactor core operating in closed fuel cycle with breeding ratio close to 1 is one of the key features of reactor designs developed within the framework of «Proryv» project direction (PD). Equilibrium reactor core is characterized by the stable reactivity and power density pattern, as well as isotopic composition of recycled plutonium. When putting into operation fast reactor using plutonium extracted from thermal reactor spent fuel in bicomponent nuclear power, the reactor core would operate rather long (more than 10 years) in transient mode, which requires special studies and special measures for controlling reactivity coast down during reactor run.
Virtual-digital modeling of fast reactor (FR) fuel cycle closure is an efficient tool in such study. In this paper, RTM-2 code package option is outlined and used. This option includes updated fuel cycle model allowing to simulate heterogeneous core layout, as well as to use radial and axial blankets.
Analytical studies have been made on sodium cooled large size reactor (1200 MW). Reactivity stabilization in such reactor is slightly more difficult as compared to lead cooled reactors, and excess reactivity exceeds βeff value attributed to BREST type reactors. Owing to heterogeneity of the core, the required excess reactivity can be decreased in transient mode down to βeff level. In equilibrium mode of such core, its breeding ratio (BR) is overrated, and this would even cause reactivity increase (although relatively small). Fuel breeding can be used for assurance of equilibrium mode with high fuel burnup.
Basically, there is no need to use blankets in the core designs under consideration. However, one should not discount the demand for fuel breeding, which is also one of the potential advantages of fast reactors. Modeling has shown the possibility of adaptable variation of BR of BN-1200 M reactor within the range of values from 1.05 to about 1.4 with the use of additional blankets (axial and radial) and enriched N15.
When using Wasserstein GAN loss function for training generative adversarial networks (GAN), it is theoretically necessary to limit the discriminators’ expressive power (so-called discriminator ...normalization). Such limitation increases the stability of GAN training at the expense of a less expressive final model. Spectral normalization is one of the normalization algorithms that involves applying a fixed operation independently to each discriminator layer. However, the optimal strength of the discriminator limitation varies for different tasks, which requires a parameterized normalization method. This paper proposes modifications to the spectral normalization algorithm that allow changing the strength of the discriminator limitation. In addition to parameterization, the proposed methods can change the degree of limitation during training, unlike the original algorithm. The quality of the obtained models is explored for each of the proposed methods.
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Re
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samples have been synthesized by thiosulfate, sulfide. and thioacetamide processes and shown to differ very little in composition. Their composition has been determined by chemical ...analysis, IR spectroscopy, and X-ray photoelectron spectroscopy (XPS). According to chemical analysis data, the samples contain an excess of sulfur compared to the stoichiometric composition Re
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. According to IR spectroscopy results, the synthesized Re
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samples contain water, hydrogen sulfate ions, and thioperrhenate ions. XPS results demonstrate the presence of sulfide, disulfide, and sulfate ions on the surface of Re
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. In addition, the rhenium in the synthesized samples is in an odd oxidation state. Possible causes of distinctions between the structural models of Re
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proposed in the literature are discussed.
A quantum key distribution system based on the subcarrier wave modulation method has been demonstrated which employs the BB84 protocol with a strong reference to generate secure bits at a rate of ...16.5 kbit/s with an error of 0.5% over an optical channel of 10 dB loss, and 18 bits/s with an error of 0.75% over 25 dB of channel loss. To the best of our knowledge, these results represent the highest channel loss reported for secure quantum key distribution using the subcarrier wave approach. A passive unidirectional scheme has been used to compensate for the polarization dependence of the phase modulators in the receiver module, which resulted in a high visibility of 98.8%. The system is thus fully insensitive to polarization fluctuations and robust to environmental changes, making the approach promising for use in optical telecommunication networks. Further improvements in secure key rate and transmission distance can be achieved by implementing the decoy states protocol or by optimizing the mean photon number used in line with experimental parameters.
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