Browsing by Area "Fizika / Physics (N002)"
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Publication Analysis of surface microdefects localization possibilities[Анализ возможностей локализации поверхностных микродефектов]research article; ;Pūras, RomualdasSakalauskas, StanislavasElectronics and electrical engineering = Электроника и электротехника = Elektronika ir elektrotechnika. Kaunas : Technologija, 2006, no. 6 (70)., p. 87-90Analysis of linear spatial resolution of vibrating Kelvin–Zisman electrode is carried out in case when the size of defective area is substantially less than diameter of vibrating probe. Dependence of relative error of voltage determination and defective area center’s coordinate determination on scanning speed was examined and influence of measuring device pass band was estimated also. Analysis of theoretical results and carried out experiments on real samples and its models allows us to state that contactless capacitic electric potential measuring devices operating on principle of vibrating Kelvin Zisman probe allows to localize single microdefects and its groups when their dimensions are less the diameter of vibrating probe, approximately measure surface electric potential and electron work function of these microdefective areas.1 - research article
; ;Davulienė, Lina; Journal of coastal research. Lawrence : Coastal Education and Research Foundation, 2012, vol. 28, no. 3., p. 557-569This paper investigates the changes in the long-term hydroclimatic conditions in the SE Baltic Sea, along the Lithuanian coast, on the basis of the monitoring data obtained within a 45-year period (1961–2005). Furthermore, the paper discusses the processes behind those changes. Time series of relevant data along the Lithuanian coast from previous centuries were used to investigate climatic variability and trends. The study finds an increased period of westerly winds during winter. During recent decades, the impact of global climate change on sea-level rise has drawn wide interest, since the coastline changes have ecological, economic, and social impacts on the coastal areas of the Baltic Sea. The analysis of the trends for the Lithuanian coastal zone found results similar to those obtained from global and regional analyses showing increasing sea levels today and in the future.3Scopus© Citations 29WOS© IF 0.496WOS© AIF 2.478Scopus© SNIP 0.501 - conference paper
; ; Gurova, EvgenijaBSSC 2009 : abstract book : August 17-21, 2009, Tallinn, Estonia. Tallinn : Tallinn University of Technology, 2009, p. 1163 - research article
;Remeikaitė-Nikienė, Nijolė ;Lujanienė, Galina ;Stirbys, Vitalijus ;Barisevičiūtė, Rūta; ; ; Ecological indicators. Amsterdam : Elsevier Science, 2017, vol. 82., p. 217-226The nature of the particulate organic matter (POM) as well as its temporal and spatial distribution and dynamics in the Curonian Lagoon (south-eastern part of the Baltic Sea) were investigated. The organic matter was characterized by the organic carbon and nitrogen content, δ13C and δ15N signatures as well as POC/Chl-a and C/N ratios. Additionally, data on hydrological, chemical and biological parameters were used for better understanding the POM distribution and dynamics. The sampling was performed at 13 stations in the Curonian Lagoon and its outflow in the Baltic Sea during the 2012–2013 period. Samples were also collected at the Nemunas River mouth in order to test the riverine impact. Obtained results showed that isotopic values of carbon and nitrogen ranged from −36.1‰ to −25.2‰ and from −0.9‰ to 15.5‰, respectively. The isotopic composition, together with the low C/N molar (∼7) and POC/Chl-a ratios (<100) of the POM, suggested the dominance of living phytoplankton in POM throughout the year with the higher input of detrital material (C/N >10, POC/Chl-a ratios >100) in late autumn − winter. The results of multivariate analysis evidenced a spatial distinction of POM distribution in the northern-transitional and central confined areas and allowed us to distinguish the main driving factors. The seasonal variation of the δ13C and δ15N values in POM (towards higher δ13C and lower δ15N values in the summer − early autumn period and lower δ13C and higher δ15N values in the late autumn − spring period) was determined by combination of factors such as availability of inorganic carbon and nitrogen, the riverine discharge, seasonal phytoplankton succession and by the short-term saline water intrusion to the northern-transitional part of the lagoon.1Scopus© Citations 19WOS© IF 3.983WOS© AIF 3.523Scopus© SNIP 1.677 8 - research article
; ;Barisevičiūtė, Rūta; ; ; ;Castaldelli, Giuseppe; ;Marzocchi, Ugo; ; ; ; Freshwater biology. Hoboken : Wiley, 2021, vol. 66, no. 6., p. 1036-10481. Tube-dwelling chironomid larvae are among the few taxa that can withstand and thrive in the organic-rich sediments typical of eutrophic freshwater ecosystems. They can have multiple effects on microbial nitrogen (N) cycling in burrow environments, but such effects cease when chironomid larvae undergo metamorphosis into flying adults and leave the sediment. 2. Here we investigated the ecological role of Chironomus plumosus by exploring the effect of its different life stages (as larva and adult midge) on microbial N transformations in a shallow freshwater lagoon by means of combined biogeochemical and molecular approaches. Results suggest that sediment bioturbation by chironomid larvae produce contrasting effects on nitrate (NO− 3 )-reduction processes. 3. Denitrification was the dominant pathway of NO− 3 reduction (>90%), primarily fuelled by NO− 3 from bottom water. In addition to pumping NO− 3 -rich bottom water within the burrows, chironomid larvae host microbiota capable of NO− 3 reduction. However, the contribution of larval microbiota is lower than that of microbes inhabiting the burrow walls. Interestingly, dinitrogen fixation co-occurred with NO− 3 reduction processes, indicating versatility of the larvae's microbial community. 4. Assuming all larvae (averaging 1,800 ind./m2) leave the sediment following metamorphosis into flying adults, we estimated a displacement of 47,787 μmol of organic N/m2 from the sediment to the atmosphere during adult emergence. This amount of particulate organic N is similar to the entire N removal stimulated by larvae denitrification over a period of 20 days. 5. Finally, the detection of N-cycling marker genes in flying adults suggests that these insects retain N-cycling microbes during metamorphosis and migration to the aerial and terrestrial ecosystems. This study provides evidence that chironomids have a multifaceted role in shaping the N cycle of aquatic ecosystems.1Scopus© Citations 6WOS© IF 3.538WOS© AIF 3.952Scopus© SNIP 1.394 Publication Branduolinio reaktoriaus matematinis modelis su vėlavimu, priklausančiu nuo reaktoriaus galios[A mathematical model of a nuclear reactor with delay depending on the power of the reactor]research article; ; ; Lietuvos matematikos rinkinys : Lietuvos matematikų draugijos XLIII konferencijos mokslo darbai. , 2002, T. 42, spec. Nr.., p. 301-3051 Publication The comparison of wind-waves and ship-wakes on the coastal zone in Tallinn Bay, the Baltic Seaconference paperBSSC 2009 : abstract book : August 17-21, 2009, Tallinn, Estonia. Tallinn : Tallinn University of Technology, 2009, p. 1813 Publication Development of distributed real time data acquisition system for radio telescope monitoringresearch article; ; ;Eglynas, Tomas; ; Gaigals, G.Space research review. Ventspils : Ventspils university college. 2013, vol. 2, p. 34-41One of the most important issues in radio astronomy is data acquisition, ensuring reliable and accurate data processing and information storage for monitoring the complex radio telescope control process. Failures arising in such control process give a significant impact for the entire space data collection system. In order to ensure a continuous monitoring, system performance, increase reliability and accuracy, it is necessary to distribute the system into several independent parts, which in case of failure are able to complement each other and at the same time independently solve a common problem. A distributed real-time data acquisition system is very important when it is needed to connect multiple devices. Moreover, the reliability of the system consisting of divided modules is increased because the failure of one module is limited to the specific functionality. The aim of this work is to propose a conceptual model for developing distributed real-time data acquisition system for radio telescope monitoring. The main advantage of such distributed data acquisition system is that the system can be extended and improved according to the needs. The distributed real-time data collection system model was designed using LabVIEW Datalogging and Supervisory Control (DSC) Module. The system allows real-time monitoring and visual data representation. All collected data is stored in the distributed system database which might be accessed remotely using cloud technology. The paper presents the results that have been obtained in the laboratory using the sensor network as a simulation of the radio telescope. The system analysis showed that the system could be adapted to the radio telescope RT-16 located in Irbene (Latvia).2 Publication E2 šuolių tikimybės branduolio ortogonaliosios U(3(A-1)) schemos bazėje[E2 the probabilities of electrical quadrupole moments in orthogonal U(3(A-1))-scheme bases]conference paper; ; Technologijos mokslo darbai Vakarų Lietuvoje : [konferencijos medžiaga]. Klaipėda : Klaipėdos universiteto leidykla, 2004, [t.] 4. ISBN 9955585536., p. 7-9- research article
; ; Petrauskas, Antanas KazimierasPhysics of atomic nuclei. New York : Pleiades Publishing, 2007, vol. 70, no. 2., p. 237-243A method for calculating electric quadrupole moments of light nuclei and probabilities of electric quadrupole transitions in them in the multiquantum approximation of the orthogonal scheme is proposed. Specific calculations of these quantities are performed for the 4 8 Be nucleus with allowance for all U(3(A − 1)) states characterized by the λ = [44] Young diagram, the quantum numbers K min and K min + 2 of the O(3A − 1)) group, and the number E = K + 2N (N = 0, 1, …, 9) of oscillator quanta. It is shown that an extension of the basis from the E = K min to the E = K min + 2 approximation leads to an increase of 15 to 45% in the electric quadrupole moments and to an increase in the transition probabilities B(E2) by a factor of 1.6 to 2.8. The inclusion of E = K + 2N (N = 0, 1, …), states involving multiquantum excitations (ρ excitations) increases additionally the results by 10 to 30%. The results of these calculations are compared with their counterparts obtained in the multiquantum approximation of the unitary scheme.1WOS© IF 0.515WOS© AIF 2.42 Publication Electrical properties of diamond-like carbon thin films[Plonųjų į deimantą panašių anglies sluoksnių elektrinės savybės]conference paper ;Dłużniewski, M. ;Lozovski, Tadeuš ;Pūras, Romualdas ;Sakalauskas, StanislavasTechnologijos mokslo darbai Vakarų Lietuvoje : [konferencijos pranešimų medžiaga]Electrical properties diamond-like carbon thin films (DLC) thin films grown by radio frequency plasma enchanced chemical vapour deposition (RF PECVD) method on n-type Si<111> substrate are analyzed and experimental results of surface electric potential and electrical conductivity for direct current and alternating current are presented in the paper. Conductivity measured of metal-DLC-Si structures for direct curreent and for alternating 1Hz frequency current was coincided whwreas conductivity for high frequency alternating current was considerably higher and slightly depended on temperature.1 Publication Elektrinių kvadrupolinių momentų skaičiavimas ortogonaliojoje U(3(A-1))-schemos bazėje[The calculations of electrical quadrupole moments in orthogonal U(3(A-1))-scheme bases]conference paperTechnologijos mokslo darbai Vakarų Lietuvoje : [konferencijos medžiaga]. Klaipėda : Klaipėdos universiteto leidykla, 2004, [t.] 4. ISBN 9955585536., p. 5-7Publication Elektrinių kvadrupolinių šuolių B(E2) tikimybės branduolio ortogonaliosios schemos daugiakvančiame artinyje Kmin[The probabilities B(E2) of elektrical quadrupole transditions in orthogonal many quanta scheme aproximation Kmin]conference paper ;Srėbalius, D.; Technologijos mokslo darbai Vakarų Lietuvoje : [konferencijos medžiaga]. , 2008, [D.] 6., p. 418-4211 Publication Elektrostatinio lauko modeliavimas MATLAB pagalba[Usage of MATLAB for modeling of electrostatic field]conference paper; Technologijos mokslo darbai Vakarų Lietuvoje : [konferencijos medžiaga]. Klaipėda, 2008, [D.] 6., p. 414-4171 - conference paper
; Gamyba ir mokslas : mokslinės konferencijos medžiaga : 1993 m. gegužės 18-19 d. Klaipėda : [Klaipėdos universiteto leidykla], 1995. ISBN 9986505208., p. 87-881 Publication Energy and radius of low-lying levels of 8/4Be nucleus in the orthogonal scheme K min+2 approximation[8/4Be branduolio žemųjų lygmenų energija ir spindulys, apskaičiuoti naudojant ortogonaliosios schemos K min+2 artinį]research article; ; ; ;Petrauskas, Antanas KazimierasLithuanian journal of physicsThe binding energy, the energies, and radii of low-lying levels of positive parity of (8)4Be are calculated within the multiquantum approximation of the orthogonal scheme by taking into account all the states labelled by the Young scheme (liambda) = [44] and quantum numbers Kmin, Kmin + 2 of group O(3(A - 1)) and their p-excitations. The convergence of results, obtained with the gradual extension of basis, and the structure of wave functions are studied. The results of calculations are compared with the results of a similar multiquantum approximation of the unitary scheme.1 Publication Equations for SU(3)-irreducible density matrix of atomic nucleus[Lygtys atomo branduolio SU(3) neredukuotinei tankio matricai skaičiuoti]research article; Petrauskas, A.Lithuanian journal of physics = Lietuvos fizikos žurnalas. Vilnius : Fisica, 2000, vol. 40, no. 6., p. 379-3851 - research article
;Petrauskas, A.; Bondarenka, VladimirasKlaipėdos universiteto mokslo darbai. Serija C, Gamtos ir matematikos mokslai. Klaipėda : [Klaipėdos universiteto leidykla], 1994, [t.] 1., p. 24-341