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

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

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

A π-Extended Donor-Acceptor-Donor Triphenylene Twin linked via a Pyrazine-bridge

Beta-amino triphenylenes can be accessed via palladium catalyzed amination of the corresponding triflate using benzophe-none imine. Transformation of amine 6 to benzoyl amide 18 is also straightforward and its wide mesophase range demon-strates that the new linkage supports columnar liquid crystal formation. Amine 6 also undergoes clean aerobic oxidation to give a new twinned structure linked through an electron-poor pyrazine ring. The new discotic liquid crystal motif contains donor and acceptor fragments, and is more oval in shape rather than disk-like. It forms a wide range columnar mesophase. Absorption spectra are strong and broad; emission is also broad and occurs with a Stokes shift of ca. 0.7 eV, indicative of charge-transfer characte

Dynamics of transcutaneous oxygen tension at the operations on the aorto-femoral segment distal of the level of aortic compression

Estimation of transcutaneous partial pressure of oxygen is the main noninvasive method of evaluation and study microhaemodynamics and tissue blood supply. Aim of the research: to study the dynamics of transcutaneous partial pressure of oxygen at surgery of aortofemoral segment performed more distally of aortic compression. Material and methods: the survey included 49 patients with arterial sclerotic disease of aortofemoral segment with comorbid Ilb-IV stage chronic lower limb ischemia according to Pokrovsky-Fountain classification, and with II-III stage chronic infrarenal abdominal aortic aneurysm according to Pokrovsky classification. The patients' age was 52-76y.o. For the assessment of peripheral microhaemodynamics we used the technique of estimation of transcutaneous partial pressure of oxygen (ТсРО2) with application of multichannel monitor of Radiometer TCM-400 system. The suggested method offers the possibility to evaluate the severity degree of microcirculatory disorders in lower limbs and to assess effectiveness of revascularization process

The astrometric Gaia-FUN-SSO observation campaign of 99 942 Apophis

Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected by ESA's Gaia mission remain recoverable after their discovery. An observation campaign on the potentially hazardous asteroid (99 942) Apophis was conducted during the asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO . The 2732 high quality astrometric observations acquired during the Gaia-FUN-SSO campaign were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as a reference. The astrometric reduction process and the precision of the newly obtained measurements are discussed. We compare the residuals of astrometric observations that we obtained using this reduction process to data sets that were individually reduced by observers and accepted by the Minor Planet Center. We obtained 2103 previously unpublished astrometric positions and provide these to the scientific community. Using these data we show that our reduction of this astrometric campaign with a reliable stellar catalog substantially improves the quality of the astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029. We show that uncertainties due to geolocations of observing stations, as well as rounding of astrometric data can introduce an unnecessary degradation in the quality of the resulting astrometric positions. Finally, we discuss the impact of our campaign reduction on the recovery process of newly discovered asteroids.Comment: Accepted for publication in A&

Time delays in PG1115+080: new estimates

We report new estimates of the time delays in the quadruple gravitationally lensed quasar PG1115+080, obtained from the monitoring data in filter R with the 1.5-m telescope at the Maidanak Mountain (Uzbekistan, Central Asia) in 2004-2006. The time delays are 16.4 days between images C and B, and 12 days between C and A1+A2, with image C being leading for both pairs. The only known estimates of the time delays in PG1115 are those based on observations by Schechter et al. (1997) -- 23.7 and 9.4 days between images C and B, C and A1+A2, respectively, as calculated by Schechter et al., and 25 and 13.3 days as revised by Barkana (1997) for the same image components with the use of another method. The new values of time delays in PG 1115+080 may be expected to provide larger estimates of the Hubble constant thus decreasing a diversity between the H_0 estimates taken from gravitationally lensed quasars and with other methods.Comment: 5 pages, 2 figures, Accepted for publication in MNRAS Letter