| 1. |
- Joss, D. T., et al.
(författare)
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The influence of quasineutron configurations on 161Ta and nearby odd-A nuclei
- 2011
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Ingår i: AIP Conf. Proc.. - : AIP. - 9780735409835 ; , s. 43-48
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Konferensbidrag (refereegranskat)abstract
- Several strongly coupled bands in the neutron-deficient nucleus 161Ta have been identified and quasiparticle configuration assignments have been made on the basis of rotational alignments and cranked shell model calculations. The level scheme elucidated for 161Ta highlights the competition between the ν(h 9/2) and ν(i 13/2) orbitals to form the yrast spectrum. The band structures in 161Ta also provide new insights into the structural features of other heavy odd-A nuclei populated with much lower reaction cross sections in this region at the proton drip line.
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| 2. |
- Leppänen, A. -P, et al.
(författare)
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Cosmogenic Be-7 in air : A complex mixture of production and transport
- 2010
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Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics. - : Elsevier BV. - 1364-6826 .- 1879-1824. ; 72:13, s. 1036-1043
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Tidskriftsartikel (refereegranskat)abstract
- The long-time series of Be-7 activity in surface air have been studied with the wavelet analysis technique in order to find coherence between Be-7 activity, theoretical production in the troposphere and climatic indices. The Be-7 activity were obtained from five different locations, Angra in the tropics in Brazil, Skane in mid-latitudes in Southern Sweden, Kiruna in Polar region in Northern Sweden, Loviisa in Southern Finland and Rovaniemi in polar region in Northern Finland. The Be-7 data from the Northern hemisphere sites where tested for coherence with theoretical production of the isotope in troposphere and with the North Atlantic Oscillation index. In the Southern hemisphere separate theoretical production was calculated in order to describe local production and Southern Annular Mode was used as the climatic index. Consistent and significant coherence were found with theoretical production at Skane, Kiruna and Loviisa at time-scales of four years or longer. At Angra and Rovaniemi sites, no coherence was detected between Be-7 theoretical tropospheric production and measured activity at ground level. The coherence between Be-7 data from Skane and Angra and climatic indices is insignificant while data from Northern and Eastern Scandinavia show clear coherence with climatic indices at time-scales of four years or longer. Additionally, significant coherence was found between the cosmic ray induced production and NAO at the time band of 8-12 years whereas the coherence between cosmic ray induced production and SAM was insignificant. This feature implies that the ground level Be-7 activity contain mixed information on both production and transport. This conclusion means that further evaluation through models which enable accurate realistic models that will be investigated in future studies.
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| 3. |
- Parikka, K., et al.
(författare)
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Functional and anionic cellulose-interacting polymers by selective chemo-enzymatic carboxylation of galactose-containing polysaccharides
- 2012
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 13:8, s. 2418-2428
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Tidskriftsartikel (refereegranskat)abstract
- Carboxylated, anionic polysaccharides were selectively prepared using a combination of enzymatic and chemical reactions. The galactose-containing polysaccharides studied were spruce galactoglucomannan, guar galactomannan, and tamarind galactoxyloglucan. The galactosyl units of the polysaccharides were first oxidized with galactose oxidase (EC 1.1.3.9) and then selectively carboxylated, resulting in the galacturonic acid derivatives with good conversion and yield. The degrees of oxidation (DO) of the products were determined by gas chromatography-mass spectrometry (GC-MS). A novel feasible electrospray ionization-mass spectrometry (ESI-MS) method was also developed for the determination of DO. The solution properties and charge densities of the products were investigated. The interaction of the products with cellulose was studied by two methods, bulk sorption onto bleached birch kraft pulp and adsorption onto nanocellulose ultrathin films by quartz crystal microbalance with dissipation (QCM-D). To study the effect of the location of the carboxylic acid groups on the physicochemical properties, polysaccharides were also oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated reaction producing polyuronic acids. The chemo-enzymatically oxidized galacturonic polysaccharides with an unmodified backbone had a better ability to interact with cellulose than the TEMPO-oxidized products. The selectively carboxylated polysaccharides can be further exploited, as such, or in the targeted functionalization of cellulose surfaces.
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