Interpretation of percolation in terms of infinity computations

In this paper, a number of traditional models related to the percolation theory has been considered by means of new computational methodology that does not use Cantor's ideas and describes infinite and infinitesimal numbers in accordance with the principle `The part is less than the whole'. It gives a possibility to work with finite, infinite, and infinitesimal quantities numerically by using a new kind of a computer - the Infinity Computer - introduced recently in by Ya.D. Sergeyev in a number of patents. The new approach does not contradict Cantor. In contrast, it can be viewed as an evolution of his deep ideas regarding the existence of different infinite numbers in a more applied way. Site percolation and gradient percolation have been studied by applying the new computational tools. It has been established that in an infinite system the phase transition point is not really a point as with respect of traditional approach. In light of new arithmetic it appears as a critical interval, rather than a critical point. Depending on "microscope" we use this interval could be regarded as finite, infinite and infinitesimal short interval. Using new approach we observed that in vicinity of percolation threshold we have many different infinite clusters instead of one infinite cluster that appears in traditional consideration.Comment: 22 pages, 7 figures. arXiv admin note: substantial text overlap with arXiv:1203.4140, arXiv:1203.316

KiDS0239-3211: A new gravitational quadruple lens candidate

We report the discovery of a candidate to quadrupole gravitationally lensed system KiDS0239-3211 based on the public data release 3 of the KiDS survey and machine learning techniques

Influence of "productive" Impurities (Cd, Na, O) on the Properties of the Cu2ZnSnS4Absorber of Model Solar Cells

The research has been supported by grant of the Ministry of Education and Science of the Republic of Kazakhstan AP09562784. The authors (D. Sergeyev) acknowledges the provision of SCAPS-1D software by Prof. Marc Burgelman. The research of A.I. Popov has been supported by the Institute of Solid State Physics (ISSP), University of Latvia (UL). ISSP UL as the Centre of Excellence is supported through the Framework Program for Euro-pean Universities Union Horizon 2020, H2020-WIDESPREAD-01–2016–2017-TeamingPhase2 under Grant Agreement No. 739508, CAMART2 project.Abstract The study focuses on the optical properties of the CZTS multicomponent semiconductor absorber with 3 % "production"impurities of Cd, Na, O within the framework of the density functional theory using the generalized gradient approximation and the SCAPS program, as well as investigates their influence on the performance and efficiency of CZTS-solar cells. The results showed that the introduction of Cd, Na, O impurities would lead to a decrease in the intensity of the absorption bands at 2.06 eV and 2.55 eV. The density of states CZTS: (Cd, Na, O) was determined from first principles, and it was revealed that impurities of Cd and O atoms would lead to a decrease in the band gap (to 0.9 eV and 0.79 eV), and an increase in Na impurity absorption (1.2 eV). It was also found that a decrease in the band gap led to a decrease in the open circuit voltage, and it was also shown that "industrial"impurities led to a decrease in the efficiency of energy conversion of solar cells to 2.34 %. © 2021 D. Sergeyev et al., published by Sciendo. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.Ministry of Education and Science of the Republic of Kazakhstan AP09562784; ISSP UL as the Centre of Excellence is supported through the Framework Program for Euro-pean Universities Union Horizon 2020, H2020-WIDESPREAD-01–2016–2017-TeamingPhase2 under Grant Agreement No. 739508, CAMART2 project

Upconversion assisted self-pulsing in a high-concentration erbium doped fiber laser

We report results on experimental and theoretical characterisation of self-pulsing in high concentration erbium doped fibre laser which is free from erbium clusters. Unlike previous models of self-pulsing accounting for pair-induced quenching (PIQ) on the clustered erbium ions, new model has been developed with accounting for statistical nature of the excitation migration and upconversion and resonance-like pumpto-signal intensity noise transfer. The obtained results are in a good agreement with the experimental data

Computer Simulations of the Band Structure and Density of States of the Linear Chains of NaCl Ions

The authors thank Eugene Kotomin and V. Kuzovkov for fruitful discussions and valuable suggestions. A.I.P thanks A.Moskina for the technical assistance in preparation of the manuscript. A.I.P also gratefully acknowledges a project LZP-2018/1-0214 from the Latvian Council of Science for partial support.The paper presents the results of first-principles computer simulations of the band structure, the density of states, and the total energy of NaCl (NaCl, Na2Cl2, Na3Cl3, Na4Cl4, Na6Cl6) linear chains of atoms. Modelling of the specified characteristics is realised in the computer code Atomistix ToolKit combined with Virtual NanoLab. The total energy depends on the number of ions in the nanoobject under study, but practically does not depend on the geometric arrangement of ions.Latvian Council of Science LZP-2018/1-0214; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Computer Simulation of the Electric Transport Properties of the FeSe Monolayer

The research has been supported by the grant of the Ministry of Education and Science of the Republic of Kazakhstan AP08052562. In addition, the research of AIP has been supported by the Latvian- Ukrainian Grant LV-UA/2018/2.The paper deals with the model research of electric transport characteristics of stressed and non-stressed FeSe monolayers. Transmission spectra, current-voltage characteristic (CVC) and differential conductivity spectra of two-dimensional FeSe nanostructure have been calculated within the framework of the density functional theory and non-equilibrium Green's functions (DFT + NEGF). It has been shown that the electrophysical properties depend on the geometry of the sample, the substrate, and the lattice constant. On CVC of non-stressed sample in the range from -1.2 V to -1 and from 1.2 V to 1.4 V, a region of negative differential resistance (NDR) has been observed. NDR is at both signs of the applied voltage due to the symmetry of the nanostructure. d2I/dV2 is used to determine the nature of the electron-phonon interaction and the features of quasiparticle tunnelling in stressed and non-stressed samples. The results obtained can be useful for calculating new elements of 2D nanoelectronics. © 2020 D. Sergeyev et al., published by Sciendo 2020. --//-- Published under the CC BY 4.0 license.Ministry of Education and Science of the Republic of Kazakhstan AP08052562, LV-UA/2018/2; The Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

KiDS-SQuaD: The KiDS Strongly lensed Quasar Detection project

New methods have been recently developed to search for strong gravitational lenses, in particular lensed quasars, in wide-field imaging surveys. Here, we compare the performance of three different, morphology- and photometry- based methods to find lens candidates over the Kilo-Degree Survey (KiDS) DR3 footprint (440 deg$^2$). The three methods are: i) a multiplet detection in KiDS-DR3 and/or Gaia-DR1, ii) direct modeling of KiDS cutouts and iii) positional offsets between different surveys (KiDS-vs-Gaia, Gaia-vs-2MASS), with purpose-built astrometric recalibrations. The first benchmark for the methods has been set by the recovery of known lenses. We are able to recover seven out of ten known lenses and pairs of quasars observed in the KiDS DR3 footprint, or eight out of ten with improved selection criteria and looser colour pre-selection. This success rate reflects the combination of all methods together, which, taken individually, performed significantly worse (four lenses each). One movelty of our analysis is that the comparison of the performances of the different methods has revealed the pros and cons of the approaches and, most of all, the complementarities. We finally provide a list of high-grade candidates found by one or more methods, awaiting spectroscopic follow-up for confirmation. Of these, KiDS 1042+0023 is to our knowledge the first confirmed lensed quasar from KiDS, exhibiting two quasar spectra at the same source redshift at either sides of a red galaxy, with uniform flux-ratio $f\approx1.25$ over the wavelength range $0.45\mu\mathrm{m}<\lambda<0.75\mu\mathrm{m}.$Comment: 12 pages, 4 figures, 4 tables, accepted for publication in MNRA

АПРИОРНАЯ ОЦЕНКА МЕТРОЛОГИЧЕСКИХ ХАРАКТЕРИСТИК РЕНТГЕНОФЛУОРЕСЦЕНТНЫХ ОПРЕДЕЛЕНИЙ СОДЕРЖАНИЯ ЭЛЕМЕНТОВ И СНИЖЕНИЯ ВЕЛИЧИНЫ МЕЖЭЛЕМЕНТНЫХ ВЛИЯНИЙ ПРИ РАЗБАВЛЕНИИ ПРОБ

A method for a priori estimation of improving the metrological characteristics of X-ray fluorescent definitions of the elements’ content and reducing the inter-elemental influences when diluting the analyzed samples by "heavy" or "light" diluents was demonstrated. The metrological characteristics were evaluated by modeling the measurement process on the scanning X-ray spectrometer using experimentally measured analytical characteristics of the spectrometer. The calculations were performed for the following models: molybdenum with the content of 1 to 80% mas. in light, neutral and heavy fillers, iron in iron ore concentrate at different degrees of dilution with lithium tetra borate and chromium oxide and uranium in corium material at different degrees of dilution with lithium tetra borate and zinc oxide. For the calculations, a method that allowed a priori estimation of the metrological characteristics of quantitative X-ray fluorescence analysis was used. The following metrological characteristics were evaluated: statistical limit of C0 detection using the 3σ criterion, differential sensitivity (η-speed estimates of the analytical line for the percentage of changes in the content of the element) and the average quadratic deviation of the measuring the σC element result content through the basic analytical parameters of the X-ray spectrometer such as integral sensitivity (I0 - experimental analysis line count speed on a single-cell sample), contrast (K-ratio of integral sensitivity to the background score speed), limit of basic hardware error A0 and theoretical coefficients (P-absorption factors) for the material under the known conditions of fluorescence excitation and measurement conditions (T-exposure). It was demonstrated that in the case of small degree of samples dilution with the heavy diluent, the effect of improving the metrological characteristics of X-ray fluorescent content definition was achieved. The same effect was achieved with more dilution by the light diluent. The proposed method of analysis could be used in planning methodical works for the selection of the degree of dilution in the analysis of solvents and powder materials.Keywords: X-ray fluorescent analysis, metrological characteristics, analytical parameters, light diluted, heavy dilutedDOI: http://dx.doi.org/10.15826/analitika.2020.24.1.006  B.D. Kalinin1, S.K. Saveliev2, J.I. Sergeyev3 1“Pretsizion Tekhnologies” Co. Lt, ul. Altai, 12, St. Petersburg, 196066, Russian Federation2Baltic State Technical University, ul.1st Krasnoarmeyskaya, 1, St. Petersburg, 195001, Russian Federation3“Spectron”, NPO LTD, ul. Tsiolkovsky, 10a, St. Petersburg, 190103, Russian FederationПредлагается способ априорной оценки улучшения метрологических характеристик рентгенофлуоресцентных определений содержания элементов и снижения межэлементных влияний при разбавлении анализируемых проб «тяжелым» или «легким» разбавителем. Метрологические характеристики оценивали путем моделирования процесса измерений на сканирующем рентгеновском спектрометре с использованием экспериментально измеренных аналитических характеристик спектрометра. Расчет метрологических характеристик был проведен для моделей: молибден при содержаниях от 1 до 80 % мас. в легком, нейтральном и тяжелом наполнителях, железо в железорудном концентрате при разных кратностях разбавления тетраработатом лития и оксидом хрома и уран в кориумном материале при разных кратностях разбавления тетраборатом лития и оксидом цинка. Для расчета был использован способ, позволяющий априорно оценивать метрологические характеристики количественного рентгенофлуоресцентного анализа: статистический предел обнаружения C0 по критерию 3s, дифференциальную чувствительность (h-скорость счета аналитической линии на процент изменения содержания элемента) и среднее квадратическое отклонение результата измерения содержания элемента sС через основные аналитические параметры рентгеновского спектрометра: интегральную чувствительность (I0 – экспериментальная скорость счета аналитической линии на одноэлементном образце), контрастность (K – отношение интегральной чувствительности к скорости счета фона), предел основной аппаратурной погрешности A0 и теоретические коэффициенты (P – абсорбционные факторы) для исследуемого материала при известных условиях возбуждения флуоресценции и условиях измерения (Т – экспозиция). В результате проведенных исследований показано, что при разбавлении проб тяжелым разбавителем при сравнительно небольшой кратности разбавления достигается эффект улучшения метрологических характеристик рентгенофлуоресцентного определения содержаний элементов и снижения величины межэлементных влияний такой же, как и при большей кратности разбавления легким разбавителем. Предлагаемый способ оценки может быть применен при планировании методических работ для выбора разбавителя и кратности разбавления при анализе растворов и порошковых материалов.Ключевые слова: рентгенофлуоресцентный анализ, метрологические характеристики, аналитические параметры, легкий разбавитель, тяжелый разбавительDOI: http://dx.doi.org/10.15826/analitika.2020.24.1.00