Search results for "Note"
showing 10 items of 10709 documents
Effect of thermal annealing on the luminescence of defective ZnO nanoparticles synthesized by pulsed laser ablation in water
2016
This work concerns ZnO nanoparticles (NPs), with sizes of tens of nm, produced by ablation with a pulsed Nd:YAG laser of a Zn plate in H2O. TEM images evidence the formation of nanoparticles with sizes of tens of nm. Moreover, HRTEM images and Raman spectra show that the distance between the crystalline planes and the vibrational modes are consistent with ZnO nanocrystal in wurtzite structure. Their optical properties are characterized by two emission bands both excited above the energy gap (3.4 eV): the first at 3.3 eV is associated with excitons recombination, the second at 2.2 eV is proposed to originate from a singly ionized oxygen vacancy. The green emission is independent of water pH,…
Assessment of Usability of Thermal Bicarbonate Mineral Water from the “Odra-5/I” Intake in Grabin Opole Silesia (SWPoland) for Therapeutic and Prophy…
2020
Szczawy termalne należą do poszukiwanych surowców balneologicznych. Ten rodzaj wód jest cennym tworzywem wykorzystywanym w uzdrowiskach w szeroko rozumianej strategii zdrowotnej - profilaktyce i rekreacji. Odkrycie w 1983 r. szczawy termalnej w Grabinie koło Opola nastąpiło przypadkiem przy okazji wykonania odwiertu do rozpoznania budowy geologicznej krystalicznego podłoża osadów mezozoicznych i kenozoicznych. Występujące w Grabinie szczawy termalne są na obszarze bloku przedsudeckiego zjawiskiem unikalnym. Skład chemiczny, a zwłaszcza duża sumaryczna zawartość soli mineralnych wód z Grabina, wskazuje na niespotykany w skali kraju typ wody mineralnej. Zawartość składników stałych jest w nie…
Laser fluence, repetition rate and pulse duration effects on paint ablation
2006
Abstract The efficiency (mm3/(J pulse)) of laser ablation of paint was investigated with nanosecond pulsed Nd:YAG lasers (λ = 532 nm) as a function of the following laser beam parameters: pulse repetition rate (1–10,000 Hz), laser fluence (0.1–5 J/cm2) and pulse duration (5 ns and 100 ns). In our study, the best ablation efficiency (η ≅ 0.3 mm3/J) was obtained with the highest repetition rate (10 kHz) at the fluence F = 1.5 J/cm2. This ablation efficiency can be associated with heat accumulation at high repetition rate, which leads to the ablation threshold decrease. Despite the low thermal diffusivity and the low optical absorption of the paint (thermal confinement regime), the ablation th…
A library of monoalkenylsilsesquioxanes as potential comonomers for synthesis of hybrid materials
2018
In this paper we demonstrate a facile and efficient synthesis of monoalkenylsubstituted POSS compounds, i.e., R7(Si8O12)-alkenyl and R7(Si8O12)(OSiMe2)-alkenyl with a functional alkenyl group of chain length (from vinyl to dec-9-enyl, with or without additional –OSiMe2– spacer between the silsesquioxane core and alkenyl moiety) and with five types of inert groups (Et, iBu, iOc, Cy, Ph) at the POSS core. These compounds constitute a library of monosubstituted POSS systems, including thorough spectroscopic and thermal characteristics. These findings could be especially useful for material chemists applying the compounds as modifiers or comonomers for copolymerization reaction, e.g., with olef…
Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites
2017
The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0-10-20-30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied…
Applications and non-idealities of submicron Al–AlOx–Nb tunnel junctions
2016
We have developed a technique to fabricate sub-micron, 0.6µm×0.6µm Al-AlOx-Nb tunnel junctions using a standard e-beam resist, angle evaporation and double oxidation of the tunneling barrier, resulting in high quality niobium, as determined by the the high measured values of the critical temperature TC ∼ 7.5 K and the gap ∆ ∼ 1.3 meV. The devices show great promise for local nanoscale thermometry in the temperature range 1 - 7.5 K. Electrical characterization of the junctions was performed at sub-Kelvin temperatures both with and without an external magnetic field, which was used to suppress superconductivity in Al and thus bring the junction into a normal-metal-insulator-superconductor (NI…
Oxidation-responsive and "clickable" poly(ethylene glycol) via copolymerization of 2-(methylthio)ethyl glycidyl ether
2016
Poly(ethylene glycol) (PEG) is a widely used biocompatible polymer. We describe a novel epoxide monomer with methyl-thioether moiety, 2-(methylthio)ethyl glycidyl ether (MTEGE), which enables the synthesis of well-defined thioether-functional poly(ethylene glycol). Random and block mPEG-b-PMTEGE copolymers (Mw/Mn = 1.05-1.17) were obtained via anionic ring opening polymerization (AROP) with molecular weights ranging from 5 600 to 12 000 g·mol-1. The statistical copolymerization of MTEGE with ethylene oxide results in a random microstructure (rEO = 0.92 ± 0.02 and rMTEG E = 1.06 ± 0.02), which was confirmed by in situ 1H NMR kinetic studies. The random copolymers are thermorespon…
Atbildību pastiprinošie apstākļi
2021
Bakalaura darbs “Atbildību pastiprinošie apstākļi” ir veltīts atbildību pastiprinošo apstākļu institūta izpētei gan vēsturiskās attīstības kontekstā, gan arī saistībā ar šī brīža pastāvošo regulējumu. Tostarp analizēta aktuālā pēdējo gadu tiesu prakse, ņemot vērā judikatūru. Bakalaura darba mērķis ir izpētīt atbildību pastiprinošo apstākļu nozīmi un praktisko pielietošanu, kā arī saskatīt esošos problēmjautājumus un sniegt atbilstošus ierosinājumus to risināšanai. Bakalaura darbā ir sekojoši uzdevumi – analizēt atbildību pastiprinošo apstākļu institūta attīstību, izprast to būtību un nozīmi, kā arī pētīt tiesu praksi un salīdzināt ārvalstu regulējumus atbildību pastiprinošo apstākļu konteks…
Universities between internationalisation and globalisation: Which language to publish?
2013
Internationalisierung ist heute als erklärtes Ziel in Strategien von Universitäten und Bildungsministerien unterschiedlichster Länder verankert. Zu Internationalisierungsbestrebungen gehören z. B. die Förderung der Mobilität von Studierenden und Hochschulpersonal oder die Schaffung vergleichbarer Studienabschlüsse. Im Streben nach Spitzenforschung sind Lehr- und Forschungspersonal sowie Doktoranden gehalten, in internationalen Projekten zu forschen und in begutachteten internationalen Foren zu publizieren. Was aber ist eine internationale Publikation? Welche Rolle spielen Sprachen im Prozess von Internationalisierung der Universitäten und Hochschulen? Welche Konsequenzen haben International…
Navigācijas ierīces neredzīgiem cilvēkiem: vajadzību apzināšana un eksperimentāla prototipēšana
2021
Neredzīgu cilvēku skaits palielinās proporcionāli cilvēku skaitam, līdz ar to, palielinās arī cilvēku skaits, kuriem ikdienas gaitās nepieciešama vai nu asistenta palīdzība vai palīglīdzekļi. Šajā darbā apzinātas, pētītas un analizētas neredzīgu cilvēku vajadzības saistībā ar navigācijas palīglīdzekļiem, to esamību, pieejamību un neredzīgu cilvēku prasības no jauniem palīglīdzekļiem, lai tos reāli lietotu. Darbā eksperimentēts ar divu veidu sensoriem, kas spēj noteikt attālumu līdz objektiem – ultraskaņas sensoru un infrasarkano sensoru. Eksperimenta mērķis – pārbaudīt abu sensoru darbspēju un trūkumus, salīdzināt to darbību trīs dažādās vidēs un pret trīs dažādiem šķēršļiem. Eksperimentējo…