Search results for "O2"
showing 10 items of 1115 documents
Ar elektroforētiskās izgulsnēšanas metodi iegūts pārejas metālu un reducēta grafēna oksīda anodmateriāls litija jonu baterijām
2022
Litija jonu baterijas (LJB) ir viena no svarīgākajiem enerģijas uzglabāšanas ierīcēm, kuras priekšrocības ir augsts enerģijas blīvums, augsts uzlādes/izlādes ciklu skaits un laba īpatnējā jauda. Tomēr pastāvīgi nepieciešams uzlabot LJB elektrodu enerģijas blīvumu. Šajā darbā tiek pētīts elektroforētiski izgulsnēts Fe2O3/TiO2/rGO kompozīts ka anods LJB. Fe2O3 ir liela lādiņietilpība (1007 mAh/g), TiO2 dod struktūras stabilitāti un rGO piemīt augsta lādiņietilpība un liela elektrovadītspēja. Darbā tiek pētītas Fe2O3/TiO2/rGO kompozīta struktūra un elektroķīmiskas īpašības kā funkcija no elektroforēzē izmantotās suspensijas sastāva. Noteikts optimālais suspensijas masas attiecības sastāvs Fe2O…
Local structural investigation of hafnia-zirconia polymorphs in powders and thin films by X-ray absorption spectroscopy
2019
Björn Matthey (Fraunhofer IKTS, Dresden) is acknowledged for providing HfO2 and ZrO2 powders on short notice after DESY’s renowned customs office punished us. Parts of this research were carried out at Petra III at DESY, a member of the Helmholtz Association (HGF). The experiments on single Si:HfO2 thin film samples were performed at the CLAESS beamline at ALBA Synchrotron with the collaboration of ALBA staff. We would like to thank Edmund Welter for assistance (in using beamline P65) and DESY for enabling this research for proposal no. 20160591 and for travel support. T.S. acknowledges the German Research Foundation (DFG) for funding this work in the frame of the project “Inferox” (project…
Isolation and differential expression of two isoforms of the ROBO2/Robo2 axon guidance receptor gene in humans and mice.
2006
AbstractExpression of Robo receptor molecules is important for axon guidance across the midline of the mammalian central nervous system. Here we describe novel isoform a of human ROBO2, which is initially strongly expressed in the fetal human brain but thereafter only weakly expressed in adult brain and a few other tissues. The known isoform b of ROBO2 shows a more or less ubiquitous expression pattern, suggesting diverse functional roles. The genomic structure and distinct expression patterns of Robo2a and Robo2b have been conserved in the mouse, but in contrast to human ROBO2a mouse Robo2a is also abundant in adult brain. Exons 1 and 2 of human ROBO2a lie in an inherently unstable DNA seg…
Contribution to the development of 100% bio-based composites : synthesis of bio-based polyepoxides, supercritical CO2 treatment of hemp fibers and im…
2018
This thesis contributes to the development of 100% bio-based hemp/epoxy composites. Current environmental issues favor the emergence of materials derived from renewable resources such as plant fibres and a wide range of bio-based building-blocks, source of epoxy prepolymers in particular. An intensive investigation of the two constituents (hemp fibres and polyepoxidic matrix) is carried out before the composites manufacturing. Supercritical CO2 treatment is applied to hemp fibres used as reinforcement in composite materials. This treatment, not optimized, leads to better individualization as well as a decrease in the hygroscopic power of the fibres. These aspects, which are essential in ord…
A field induced ferromagnetic-like transition below 2.8 K in Li2CuO2: An experimental and theoretical study
1998
The low temperature magnetic properties of the Li2CuO2 compound have been investigated by means of superconducting quantum interference device magnetometry. We find in addition to an antiferromagnetic phase below 9.5 K a ferromagnetic-like steep rise of the magnetization around 2.8 K. The observed low temperature behavior is discussed by considering second and fourth order magnetocrystalline effective anisotropy coefficients, in addition to the exchange couplings reported in the literature. Work at the Institut de Ciencia dels Materials was supported by the Spanish Comisión Interministerial de Ciencia y Technología Grant No. CICYT MAT 96-1037.
FISCALITY – RELEVANT FACTOR INFLUENCING THE BUSINESS ENVIRONMENT
2013
Main tool for macroeconomic management - fiscal policy consists in establishing the levels of taxation and spending in order to influence macroeconomic performance. Fiscal policy, promoted by the government authorities of any contemporary state, is directed usually to achieving microeconomic and macroeconomic goals deriving from the roles the state must fulfill in the economy, respectively the allocative role, distributive, regulatory and the stabilizer role. Governmental authorities, through the production and supply of public goods that are financed at the expense of taxes or duties, or on the public debt, affect both individuals’ utility functions and production functions of economic age…
Slight differences in community structure and biodiversity of fish associated to a Cymodocea nodosa meadow in a shallow CO2 vent
2018
Naturally acidified environments are used to test ecological hypotheses about the effects of ocean acidification on complex communities. Here, we used a shallow Mediterranean CO2 vent to study the coastal fish assemblages associated to Cymodocea nodosa seagrass meadows, long-term exposed to high pCO2 / low pH conditions. In particular, by using underwater visual census method, we assessed the structure and the biodiversity of fish assemblages living in a low pH site and in two control sites, in two periods of the year featured by dissimilar seagrass structure. The aim of this study was to test the effect of different pH on fish assemblages mediated by the habitat-forming structural species …
O2 Loaded Germanosilicate Optical Fibers: Experimental In Situ Investigation and Ab Initio Simulation Study of GLPC Evolution under Irradiation
2022
International audience; In this work we present a combined experimental and ab initio simulation investigation concerning the Germanium Lone Pair Center (GLPC), its interaction with molecular oxygen (O2), and evolution under irradiation. First, O2 loading has been applied here to Ge-doped optical fibers to reduce the concentration of GLPC point defects. Next, by means of cathodoluminescence in situ experiments, we found evidence that the 10 keV electron irradiation of the treated optical fibers induces the generation of GLPC centers, while in nonloaded optical fibers, the irradiation causes the bleaching of the pre-existing GLPC. Ab initio calculations were performed to investigate the reac…
Iekštelpu gaisa piesārņojums pirmsskolas vecuma bērnu izglītības iestādēs
2019
Bakalaura darba “Iekštelpu piesārņojums pirmsskolas vecuma bērnu izglītības iestādēs” analizēts un aprakstīts iekštelpu vides vispārīgs raksturojums un hipotētiskie piesārņojuma avoti. Eksperimentālā daļā veikti oglekļa dioksīda (CO2), cieto daļiņu PM2.5, PM10, formaldehīda (HCHO), gaistošo savienojumu (TVOC) vielu un mikroklimata (temperatūra, relatīvais mitrums) mērījumi. Laika posmā no 2019. gada ziemas līdz 2019. gada pavasarim apmeklētas 3 pirmsskolas izglītības iestādes (PII) – divas Rīgā, Ziepniekkalnā un viena Iecavā. Iegūtie rezultāti salīdzināti ar normatīviem un Pasaules veselības organizācijas (PVO) rekomendējamajiem normatīviem.