| 1. |
- Shovsky, Oleksandr, et al.
(författare)
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Adsorption Characteristics of Stoichiometric and Nonstoichiometric Molecular Polyelectrolyte Complexes on Silicon Oxynitride Surfaces
- 2011
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 27:3, s. 1044-1050
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption properties of stoichiometric and nonstoichiometric polyelectrolyte complexes (PECs) have been investigated by means of dual polarization interferometry (DPI) and X-ray photoelectron spectroscopy (XPS). Poly(sodium styrenesulfonate) (NaPSS) of molecular weight 4300 g/mol was used as polyanion, and two bottle-brush copolymers possessing different molar ratios of the cationic segment methacryloxyethyltrimethylammonium chloride (METAC) and the nonionic segment poly(ethylene oxide) methyl ether methacrylate (PEO(45)MEMA) were used as polycations. They are referred to as PEO(45)MEMA:METAC-25 and PEO(45)MEMA:METAC-50, where the last digits denote the mol % of charged main-chain segments. The time evolution of the adsorbed amount, thickness, and refractive index of the PEC layers were determined in aqueous solution using DPI. We demonstrate that cationic, uncharged, and negatively charged complexes adsorb to negatively charged silicon oxynitride and that maximum adsorption is achieved when small amounts of PSS are present in the complexes. The surface composition of the adsorbed PEC layers was estimated from XPS measurements that demonstrated very low content of NaPSS. On the basis of these data, the PEC adsorption mechanism is discussed and the competition between PSS and negative surface sites for association with the cationic polyelectrolyte is identified as a key issue.
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| 2. |
- Varga, Oleksandr, et al.
(författare)
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First record of the genus Aplomerus Provancher, 1886 (Hymenoptera: Ichneumonidae: Xoridinae) from the Oriental region, with descriptions of two new species.
- 2014
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Ingår i: Zootaxa. - : Magnolia Press. - 1175-5326 .- 1175-5334. ; :3815, s. 591-9
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Tidskriftsartikel (refereegranskat)abstract
- The genus Aplomerus Provancher, 1886 (Hymenoptera, Ichneumonidae) is a small genus of the subfamily Xoridinae. Two new species from Asia, A. orientalis Varga & Reshchikov sp. n. from Thailand and A. phamae Broad sp. n. from Vietnam, are described and illustrated. An identification key for Asian species is provided. These are the first records of the genus from the Oriental region and increases the known number of Aplomerus species to eight, with a disjunct distribution of North America, Japan and south-east Asia.
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