Nonlinear properties of Li2B4O7:Ag borate glasses with “Li2B4O7:Ag nanoparticles” interface region formed by thermal treatment in hydrogen atmosphere and in vacuum are investigated. From the results ...of plasmon absorption and normalized transmission measurements in Z-scan regime it was ascertained that “Li2B4O7:AgNPs” interface region changes the character of nonlinear refraction of Li2B4O7:Ag glass from negative to positive, and, due to plasmon resonance, increases significantly its nonlinear properties. In particular, the observed growth of nonlinear refractive index n2 is more than four orders of magnitude.
•Lithium tetraborate glasses activated with Dy and co-activated with Dy and Ag were obtained.•Optical absorption, luminescence spectra, decay kinetics, and quantum yield were studied.•An enhancement ...of Dy3+ luminescence in the Dy-Ag-co-activated glass was observed.•The energy transfer processes from Ag+ ions and Ag nanoclusters to Dy3+ ions were discussed.•The Li2B4O7:Dy,Ag glass is a promising luminescent material for white emission.
In this work we study and analyse the optical-luminescence properties of the lithium tetraborate (Li2B4O7 or Li2O–2B2O3) glasses activated with dysprosium (Dy) and co-activated with Dy and silver (Ag). Our analysis reveals the presence of Dy3+ (4f9) and Ag+ (4d10) ions as well as non-plasmonic Ag nanoclusters in the lithium tetraborate glass network. In the luminescence emission spectra were detected two strong and narrow blue and yellow bands attributed to Dy3+ ions as well as two broad unresolved bands covering violet-green spectral range, which correspond to Ag+ ions and Ag nanoclusters. An increase in the luminescence intensity of Dy3+ and an increase in the corresponding quantum yield as a result of Ag co-activation were obtained. Mechanisms underlying the energy transfer processes from Ag+ ions and Ag nanoclusters to Dy3+ ions have been discussed. Our results contribute to the development of the glassy luminescent materials for the white spectral range.
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Estimation is an essential step of software development project planning that has a significant impact on project success—underestimation often leads to problems with the delivery or even causes ...project failure. An important aspect that the classical estimation methods are usually missing is the Agile nature of development processes in the implementation phase. The estimation method proposed in this article aims at software development projects implemented by Scrum teams with differentiated specializations. The method is based on the authors’ system of working-time balance equations and the approach to measuring project scope with time-based units—normalized development estimates. In order to reduce efforts spent on the estimation itself, an analysis of dependencies among project tasks is not mandatory. The outputs of the methods are not recommended to be treated as commitments; instead, they are supposed to be used to inform project stakeholders about the forecasted duration of a potential project. The method is simple enough to allow even an inexpensive spreadsheet-based implementation.
The structure of a multilevel process control system (MPCS) with the organization of data exchange via a multiport memory based on a modular principle has been developed in this work. The use of a ...modular principle enables to effectively organize enhancement and modification of a system designed. The structure of the multilevel system for process control includes three levels: data acquisition and control actuators; supervisory level and process control; operator control and decision-making. The key feature of each MPCS level is its hardware and software components along with the problems to be solved by them. Firstly, the level of data acquisition and control actuators enables performing such functions as data acquisition, data accumulation from the sensors and data processing. This level employs hardware and software tools based on the microcontrollers of STM8 family. Secondly, the supervisory level and process control exhibits data acquisition, accumulation process control data, online data processing, forecasting of a behavior of processes and controlled objects. Data processing of this level reduces the volume of data that have to be transferred to the upper level and thereby lowers bandwidth requirements of communication channels. The hardware and software tools of this level must work in real time. Thirdly, at the level of operator control and decision-making the following tasks are performed: data acquisition, data storage and data processing; processing of video streams, recognition of images and scenes in vision systems; decision-making; synchronization of universal time in a distributed system; synchronization of operation of the distributed subsystems; visualization and representation of the implementation process. In addition, this level contains a SCADA system, the main function of which is to create an operator interface and collect data on process control. As a result of the research requirements for exchanging and storing data were formed, the structure of the device to store and exchange data was designed and multi-port memory controller was synthesized. The method of conflict-free parallel data exchange using multi-port memory was improved by matching the intensity of access to data with the intensity of data flow, which allows determining the necessary performance of the random access memory.
Проаналізовано сучасні підходи до організації ефективного управління сучасними підприємствами. Отримані результати аналізу дають змогу стверджувати, що розвиток енергетичної галузі України, як і ...інших галузей, неможливий без впровадження принципів технології "Industry 4.0" та розроблення систем управління підприємством має відбуватися з урахуванням міжнародних стандартів: ANSI/ISA-95 і IEC 62264–1. Побудова власної ієрархічної системи управління під конкретне підприємство має ґрунтуватися на використанні вже існуючих базових програмно-апаратних складових, що дасть змогу істотно зменшити її вартість. Відповідно, виникає задача узгодження роботи сумісного функціонування базових програмно-апаратних складових, а саме: дослідження динаміки функціонування ієрархічної системи. Для аналізу функціонування таких систем запропоновано моделі, які ґрунтуються на теорії ієрархічних та простих мереж Петрі, які дають змогу дослідити динаміку функціонування розроблювальної системи. Окрім цього, модель з використанням ієрархічних мереж Петрі надає можливість дослідити інформаційні потоки між ієрархічними рівнями та їх взаємний вплив. Наведено результати апробації побудованих моделей, а саме: приклад аналізу функціонування багаторівневої ієрархічної системи управління технологічними процесами підприємства. Отримані результати дають змогу стверджувати, що розроблена багаторівнева ієрархічна система управління технологічними процесами підприємства функціонує правильно, усі стани досяжні, а тупики відсутні.
Free-volume structure of glassy lithium tetraborate Li2B4O7 is studied as compared with isocompositional crystal using positron annihilation lifetime spectroscopy in mixed positron-trapping and ...Ps-decaying modes exploring three-term decomposed positron lifetime spectra. The longest-lived lifetime component in Li2B4O7 glass is explained due to low-electron density spaces between neighbouring tetraborate groups, while second component is attributed to positron trapping in lithium vacancy-type complexes. Crystal-to-glass transition in free-volume structure of Li2B4O7 is examined with x3-x2-coupling decomposition algorithm. Assuming tight interconnection between atomic-deficient void structure of crystalline and glassy lithium tetraborates, the vitrification from crystalline state is described as expansion of positron-trapping complexes involving singly-ionized lithium vacancies in more spatially-extended positron-trapping sites, this being accompanied by large number of Ps-traps appeared preferentially in boron-oxide network of tetraborate structural units.
•Positron annihilation in Li2B4O7 due to mixed positron and positronium sites•Substantial role of positron and positronium trapping in lithium tetraborate glass•Defect-specific positron lifetime close to 0.455ns in glassy Li2B4O7•Vitrification due to expansion of positron-trapping sites on lithium vacancies
To solve large number of digital signal processing problems, such as on-board radar-location or hydro-acoustic systems, it is necessary to perform discrete trigonometric transforms over intensive ...data flows in real time with the constraints on size and power consumption. To solve this problem, the hardware implementation in the form of the VLSI has been proposed. In particular, we improve an algorithm for the fast cosine and sine Fourier transforms with a focus on the parallel-streaming hardware implementation. A flow graph of the improved algorithm has been developed on the basis of addition, subtraction and multiplication of real numbers with the relation scheme of algorithms. A linear projection of the improved algorithm for fast cosine and sine Fourier transforms on the axis parallel to the data transmission has been obtained. This makes it possible to change the type and dimensions of the transforms. Further, we develop a structure of 2-4-8-16-point processor for fast cosine and sine Fourier transforms. Such an implementation provides a reduction of the dimensions, energy consumption and performance of the transforms in real time.
Abstract
Single particle imaging (SPI) is a promising method of native structure determination, which has undergone fast progress with the development of x-ray free-electron lasers. Large amounts of ...data are collected during SPI experiments, driving the need for automated data analysis. The necessary data analysis pipeline has a number of steps including binary object classification (single versus non-single hits). Classification and object detection are areas where deep neural networks currently outperform other approaches. In this work, we use the fast object detector networks YOLOv2 and YOLOv3. By exploiting transfer learning, a moderate amount of data is sufficient to train the neural network. We demonstrate here that a convolutional neural network can be successfully used to classify data from SPI experiments. We compare the results of classification for the two different networks, with different depth and architecture, by applying them to the same SPI data with different data representation. The best results are obtained for diffracted intensity represented by color images on a linear scale using YOLOv2 for classification. It shows an accuracy of about 95% with precision and recall of about 50% and 60%, respectively, in comparison to manual data classification.
Interspecific hybridization has occurred relatively frequently during the evolution of vertebrates. This process usually abolishes reproductive isolation between the parental species. Moreover, it ...results in the exchange of genetic material and can lead to hybridogenic speciation. Hybridization between species has predominately been observed at the interspecific level, whereas intergeneric hybridization is rarer. Here, using whole-genome sequencing analysis, we describe clear and reliable signals of intergeneric introgression between the three-spined stickleback (
Gasterosteus aculeatus
) and its distant mostly freshwater relative the nine-spined stickleback (
Pungitius pungitius
) that inhabit northwestern Russia. Through comparative analysis, we demonstrate that such introgression phenomena apparently take place in the moderate-salinity White Sea basin, although it is not detected in Japanese sea stickleback populations. Bioinformatical analysis of the sites influenced by introgression showed that they are located near transposable elements, whereas those in protein-coding sequences are mostly found in membrane-associated and alternative splicing-related genes.
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