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Wyszukujesz frazę "optically stimulated" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Investigating the filling state of OSL detector traps with the optical sampling method
Autorzy:
Mandowska, Ewa
Smyka, Robert
Mandowski, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/2106412.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optically stimulated luminescence
OSL
ionizing radiation detectors
radiative recombination
signal loss
Opis:
Optically stimulated luminescence (OSL) and thermoluminescence (TL) methods are commonly used in dosimetry of ionizing radiation and dating of archaeological and geological objects. A typical disadvantage of OSL detectors is signal loss over a longer time scale. In this article, we present a method of studying this phenomenon as well as monitoring the state of the detector by means of optical sampling. The method was used to determine the OSL signal loss (fading) characteristics of selected potassium feldspars.
Źródło:
Metrology and Measurement Systems; 2022, 29, 2; 361--371
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New luminescence ages reveal Early to Middle Weichselian deposits in central Latvia
Autorzy:
Lamsters, K.
Kalińska-Nartiša, E.
Zelčs, V.
Alexanderson, H.
Powiązania:
https://bibliotekanauki.pl/articles/2060383.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
optically stimulated luminescence (OSL) dating
subglacial bedforms
Early Weichselian
Middle Weichselian
central Latvia
Opis:
New optically stimulated luminescence (OSL) ages show that sandy deposits overlain by Late Weichselian subglacial till in central Latvia are of Early to Middle Weichselian age. The finer chronological resolution of unconsolidated sediment deposition in the Central Latvian Lowland (CLL) remains relatively unstudied, and here we provide a first characterisation of the deposits with respect to their age. Three OSL ages ranging between 84 ± 9 ka and 112 ± 11 ka suggest that the deposits studied in the CLL are of Early Weichselian age (MIS 5). We found no Middle Weichselian deposits in the CLL, and assume that any such younger sediments might have been eroded during the advance of the Zemgale Lobe in the Late Weichselian. One site, in the ice-marginal zone adjacent to the interlobate area, has nevertheless deposits dated to 44 ± 10 ka corresponding to the Middle Weichselian (MIS 3). Our results are compatible with existing ESR ages on three sets of Portlandia arctica shells from the central part of the lowland; the shells had been incorporated into glacial deposits during later glacial advances. Finally, our findings largely support ice-free conditions during the Early and Middle Weichselian in the middle and southern part of central Latvia.
Źródło:
Geological Quarterly; 2017, 61, 2; 480--490
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late Glacial and Holocene vegetation and climate history of an alpine wetland on the Qinghai-Tibetan Plateau
Autorzy:
Liu, D. L.
Chen, G.
Lai, Z.
Weis, H.
Zhou, G.
Peng, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059730.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Late Glacial
Holocene
Qinghai-Tibetan Plateau
alpine wetland
optically stimulated luminescence
pollen analysis
Opis:
This study provides a vegetation and climate history of an alpine wetland in the centre of China’s Qinghai–Tibetan Plateau (QTP) over the last 14.8 ka. High resolution climate proxies include vegetation (pollen), geochemical (Ba, Rb, δ13C) and physical (particle size and magnetic susceptibility) data; optically stimulated luminescence (OSL) and AMS radiocarbon dating were used to reconstruct the environmental changes in the wetland ecosystem. Based on physical and geochemical proxies, the sucession divided into five stratigraphic units encompassing time intervals of 14.76–14.31, 14.31–13.17, 13.17–4.47, 4.47–0.51 and 0.51–0 ka. The average sedimentation rate of all these units was 0.098 mm/a. The study showed that this ecosystem was sensitive to climate change.
Źródło:
Geological Quarterly; 2013, 57, 2; 261--268
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rate of loess accumulation in Europe in the Late Weichselian (Late Vistulian)
Autorzy:
Fedorowicz, S.
Łanczont, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059500.pdf
Data publikacji:
2007
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
European loess
Upper Weichselian
mass accumulation rates (MAR)
TL age
optically stimulated luminescence (OSL)
Opis:
The European loess profiles provides evidence of changes in climate in the last glacial cycle. The final stage of loess accumulation took place in the youngest part of the last glacial (28 to 12 ka BP). Loess accumulated in two periods: from 28 to 18 ka BP and from 18 to 13 ka BP. These two stages were separated by a short phase of weaker aeolian activity and weak pedogenesis (initial tundra gleyed soils). The loess sedimentation rate can be defined as a mass accumulation rate (MAR ex pressed in g/m2/year). This value was calculated by Frechen et al. (2003) for several dozen loess sites across western and central Europe. In this paper we calculate the MAR for several loess sites in Poland and Ukraine. The MAR distribution across Poland and Ukraine is uneven in these two intervals. The MAR values oscillate between 100 to several thou sand g/m2/year. They markedly in crease eastwards, which may be explained by the latitudinal gradient of periglacial climate in the LateWeichselian (= Late Vistulian). The MAR distribution along a N-S trend confirms its large range in western and central Europe. However, the most easterly profiles (Polish and Ukrainian ones) show less variable thick nesses as the MAR was stable at a relatively low level from several hundred to more than a thou sand g/m2/year. This stability of the MAR characterized both loess-forming intervals in this part of Europe.
Źródło:
Geological Quarterly; 2007, 51, 2; 193-202
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An aeolian or a glaciolacustrine record? A case study from Mieļupīte, Middle Gauja Lowland, northeast Latvia
Autorzy:
Nartišs, M.
Kalińska-Nartiša, E.
Powiązania:
https://bibliotekanauki.pl/articles/94211.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
dune
ice-dammed lake
quartz grain
optically stimulated luminescence
Linkuva ice-marginal zone
Baltic States
wydma
jezioro lodowe
ziarna kwarcowe
optycznie stymulowana luminescencja
kraje bałtyckie
Opis:
In the Middle Gauja Lowland, northeast Latvia, dunes are distributed over a vast glaciolacustrine plain that formed during the retreat of the Fennoscandian ice sheet. Such a direct contact between aeolian and glaciolacustrine sediments can be used to infer depositional settings and decipher to what extent these sediments bear an aeolian component. Our proxies, although preliminary, reveal a limited range of variation in grain-size parameters, a significant presence of quartz grains with silica precipitation and matt-surface grains of various rounding degrees and massive structure combined with horizontal lamination. These are indicative of periglacial-aeolian depositional conditions in the foreland of the Linkuva ice-marginal zone. Sedimentary characteristics do not match a single luminescence date of 9.2±0.6 ka, which significantly postdates the minimum age of the Linkuva ice-marginal zone with 10Be ages between 15.4 and 12.0 ka. Whether deposition started directly after drainage of the Middle Gauja ice-dammed lake or if there is a gap of 2.8–6.2 ka is a matter of debate; only future studies at higher OSL resolution could resolve this.
Źródło:
Geologos; 2017, 23, 1; 15-28
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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