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111.
A polyvinylidene fluoride film has been bombarded with accelerated (1–5 MeV) helium ions at a fluence of 1015 ion/cm2. Unlike the completely amorphous structure of the unirradiated polymer, the weight fraction of the crystalline modification in the irradiated polymer is 0.86–0.90, which is indicative of the efficient conversion of the amorphous structures of the polymer pseudo-network into the crystalline ones. Irradiation with 1-MeV ions leads to the greatest changes in the fraction of the crystalline modification and the glass-transition and flow temperatures of the polymer. The detachment of fluorine and the surface carbonization of the irradiated polymer occur under the ion beam. 相似文献
112.
G. F. Novikov E. V. Rabenok Ya. I. Estrin Yu. A. Ol’hov E. R. Badamshina 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(10):1790-1794
The effect of small (0.002–0.018 wt %) additions of single-walled carbon nanotubes on the dielectric properties and electrical conductivity of crosslinked polyurethane elastomer is studied in the temperature range of 133–453 K and the 10?3 to 105 Hz range of electric field frequencies. It is shown that the dependence of direct current conductivity σ dc on temperature deviates significantly from the Arrhenius dependence and is described by the Vogel-Fulcher-Tamman equation σ dc = σ dc0exp{?DT 0/(T ? T 0)}, where T 0 is the Vogel temperature and D is the strength parameter. A correlation is found between the nonmonotonic dependences of the glass transition temperature (T g), D parameter, and σ dc and the concentration of nanotubes with earlier results for their effects on the physicomechanical characteristics (strength and Young’s modulus) of these systems. 相似文献
113.
Utilization of Slovak bentonites in deposition of high-level radioactive waste and spent nuclear fuel 总被引:2,自引:0,他引:2
Michal Galambo? Ol��ga Rosskopfov�� Jana Kuf?��kov�� Pavol Rajec 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):765-777
The basic strategic aims in the field of managing high-level radioactive waste and liquidation of nuclear power plants are all contained in the Energy policy of the Slovak Republic. Its aim is to resolve the concept of the backside of the nuclear energetics fuel cycle??long-term deposition of high-level radioactive waste and spent nuclear fuel (SNF). The most important form of high-level radioactive waste and SNF long-term deposition is their deposition in deep geological formations created by natural as well as engineering barriers used to isolate the long-lived radionuclides from the biosphere. The basic components of these barriers are clays, of which bentonite is generally referred to as the most suitable clay material. There are a few significant bentonite deposits in the Slovak Republic: Jel?ový potok, Kopernica, Lastovce, Lieskovec, Dolná Ves. The review article summarizes the information on geotechnical properties of Slovak bentonites published up-to-date, which is inevitable to know for the intention of their use. It highlights the advantages and shows drawbacks of five Slovak deposits. It suggests further research direction, to draw a thorough hydraulical, microbial and radiation profile of Slovak bentonites. 相似文献
114.
Several crude oil accumulations in the Pannonian Basin are trapped in uncommonly hot (>170°C) reservoirs. Their maturities range from mature to very mature on the basis of cracking parameters of their biological marker homologous series (ratio of products to reactants). A stable carbon isotopic study of these oils, poor in biological markers commonly used for correlation purposes, did not provide a reliable oil-to-oil correlation. As an alternative tool, the hydrogen isotope compositions of oil fractions separated on the basis of different polarities were measured, and hydrogen isotope type-curves were generated for a set of mature to very mature crude oil samples. This method of presenting hydrogen isotope composition of fractions as type-curves is novel. Nineteen samples (17 crude oils from SE-Hungary, 1 oil condensate and 1 artificial oil) were chosen for the present study. The aim was to examine the applicability of hydrogen isotope type-curves in oil-to-oil correlation and to test the simultaneous application of carbon and hydrogen isotope type-curves in the field of petroleum geochemistry. We have shown that, although the conventionally used co-variation plots proved to be inadequate for the correlation of these hot and mature oils, the simultaneous use of carbon and the newly introduced hydrogen isotope type-curves allows us to group and distinguish oils of different origins. 相似文献
115.
116.
A new simple ultra-high-performance liquid chromatography method with diode array detection (UHPLC-DAD) was developed for
chemical fingerprinting analysis of extracellular metabolites in fermentation broth of Geosmithia spp. The SPE method employing Oasis MCX strong cation-exchange mixed-mode polymeric sorbent was chosen for extraction of
the metabolites. The analyses were performed on an Acquity UPLC BEH C18 column (100 × 2.1 mm i.d.; particle size, 1.7 μm;
Waters) using a gradient elution program with an aqueous solution of trifluoroacetic acid and acetonitrile as the mobile phase.
The applicability of the method was proved by analysis of 38 strains produced by different species and isolated from different
sources (hosts). The results revealed the correlation of obtained UHPLC-DAD fingerprints with taxonomical identity. 相似文献
117.
Attila Gilányi Katarzyna Troczka-Pawelec 《Journal of Mathematical Analysis and Applications》2011,382(2):814-821
Related to the theory of convex and subadditive functions, we investigate weakly subquadratic mappings, that is, solutions of the inequality
118.
We consider biquadratic number fields whose maximal orders have power integral bases consisting of units. We prove an effective
and efficient criteria to decide whether the maximal order of a biquadratic field has a unit power integral basis or not.
In particular we can determine all trivial biquadratic fields whose maximal orders have a unit power integral basis. 相似文献
119.
Zachary Abel Brad Ballinger Prosenjit Bose S��bastien Collette Vida Dujmovi? Ferran Hurtado Scott Duke Kominers Stefan Langerman Attila P��r David R. Wood 《Graphs and Combinatorics》2011,27(1):47-60
We prove the following generalised empty pentagon theorem for every integer ℓ ≥ 2, every sufficiently large set of points in the plane contains ℓ collinear points or an empty pentagon. As an application, we settle the next open case of the “big line or big clique” conjecture
of Kára, Pór, and Wood [Discrete Comput. Geom. 34(3):497–506, 2005]. 相似文献
120.
Orentienė A Olšauskaitė V Vičkačkaitė V Padarauskas A 《Journal of chromatography. A》2011,1218(39):6884-6891
The potential of 1.7 μm ethylene bridged hybrid silica phase was investigated for the separation of twelve imidazolium-based ionic liquid cations. U-shaped retention profile was observed for all solutes with an increase in retention at both low and high acetonitrile content. Chromatographic behaviour of imidazolium cations in both hydrophilic interaction chromatography (HILIC) and per aqueous liquid chromatography (PALC) modes was studied by varying key parameters such as buffer concentration and pH, acid additive, organic modifier and column temperature. Experimental data provided some evidences that under PALC conditions cationic solutes are retained predominantly by mixed hydrophobic/ion-exchange interactions. In the HILIC mode, both partitioning and ion-exchange interactions are responsible for the retention of solutes. Compared to PALC, HILIC provided significantly higher efficiencies with less or even no peak tailing, better separation selectivity and greater resistance to overload. In PALC mode gradient elution was required to achieve adequate retentivity of all solutes but selectivity was not sufficient to distinguish between solutes with very similar hydrophobicity. In contrast, under HILIC conditions twelve solutes were almost completely resolved in less than 4 min by using isocratic elution. Summarizing, it could be concluded that ethylene bridged hybrid silica column providing a dual retention mechanism offers the possibility of selecting between the two retention modes with opposite separation selectivity, just by changing the composition of the mobile phase. 相似文献