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41.
42.
Zvonimir Janko 《Archiv der Mathematik》1961,12(1):280-281
Ohne Zusammenfassung 相似文献
43.
Zvonimir Janko 《Mathematische Zeitschrift》1962,79(1):422-424
Ohne ZusammenfassungHerrnReinhold Baer zum 60. Geburtstag am 22. Juli 1962 gewidmet 相似文献
44.
45.
Igor Jerković Ani Radonić Marina Kranjac Marina Zekić Zvonimir Marijanović Senka Gudić Maja Kliškić 《Chemical Papers》2016,70(6):726-736
Headspace solid-phase micro-extraction (HS-SPME) and ultrasonic solvent extraction (USE) were used for red clover honey volatiles extraction. The extracts were analysed using gas chromatography and mass spectrometry (GC-MS). Lilac aldehyde isomers dominated in the headspace (individual range from 7.6 % to 21.4 %) followed by phenylacetaldehyde (10.1–31.2 %) and benzaldehyde (7.0–15.7 %). Higher aliphatic alcohols and hydrocarbons were the predominant constituents of the honey extracts. The honey and its extracts exhibited rather weak anti-radical activity (DPPH assay) and total antioxidant activity (FRAP assay). On the other hand, the honey’s inhibitive properties towards the corrosion of AA 2017A alloy in NaCl solution (potentiodynamic polarisation and potentiostatic pulse measurements) revealed the honey to be a very good anodic inhibitor (efficiency up to 76 %) while the honey extracts (USE) showed better inhibition efficacy. 相似文献
46.
In this paper we derive and mathematically justify models of micropolar rods and plates from the equations of linearized micropolar elasticity. Derivation is based on the asymptotic techniques with respect to the small parameter being the thickness of the elastic body we consider. Justification of the models is obtained through the convergence result for the displacement and microrotation fields when the thickness tends to zero. The limiting microrotation is then related to the macrorotation of the cross–section (transversal segment) and the model is rewritten in terms of macroscopic unknowns. The obtained models are recognized as being either the Reissner–Mindlin plate or the Timoshenko beam type. 相似文献
47.
The terpolymerization of acryionitrile, styrene, and pentabromophenyl acrylate in dimethylformamide solution was investigated. Experimental terpolymerization data agreed well with calculations using the Alfrey-Goldfinger equation. The relationship between monomer feed and terpolymer compositions are presented on triangular coordinate graphs, and the lines of unique and the lines of binary azeotropic composition were identified. No point of true ternary azeotropic composition was found but a “pseudoazeotropic” region was identified. The experimental results of the terpolymerization agreed well with the theoretical curves over a wide range of monomer composition up to high conversions. The influence of pentabromophenyl acrylate units on the thermal and flammability characteristics of the terpolymers are described. 相似文献
48.
Abstract The terpolymerization of butadiene, acrylonitrile, and methacrylic acid in emulsion, using potassium persulfate as initiator and sodium dioctylsulphosuccinate as emulsifier, was investigated. For the binary system butadiene (M1) and methacrylic acid (M2), the following monomer reactivity ratios were determined: r12 = 0.18 ± 0.05 and r21 = 0.52 ± 0.09. When polymerizations were stopped at low conversions they gave terpolymers which show good agreement between experimental and theoretical copolymerization composition data, calculated from the Alfrey-Goldfinger equation. The relationships between monomer feed and terpolymer compositions are presented on triangular coordinate graphs as proposed by Slocombe. By using a computer program, the lines of unique composition and the lines of binary azeotropic composition were established. No point of true azeotropic composition was found, but a “pseudo-azeotropic” region was recognized. The influence of composition on glass transition temperature and thermal characteristics of the terpolymers is described. 相似文献
49.
Kinetic studies of the free radical copolymerization of N-(2,4,6- tribromophenyl) maleimide (TBPMI) with styrene in solution were carried out. The thermal and flammability characteristics of the resulting polymers were also investigated. The monomer reactivity ratios were found to be r 1 = 0.006 ± 0.0026 (TBPMI) and r 2 = 0.086 ± 0.0023, and the activation energy of the copolymerization reaction was Ea = 73.6 kJ/mol. The resulting copolymers showed an alternating structure regardless to the monomer feed composition. The molecular weights of the copolymers obtained are relatively high and gradually increase by increasing the TBPMI fraction in the feed, whereas the Tg's showed similar values (540 K) for the equimolar ratio of the comonomers. The course of copolymerization up to high conversion was followed by microcalorimetry and is characterized by a remarkable increase of the initial reaction rate as the fraction of TBPMI was increased; it is also higher at higher total monomer concentrations. However, the overall conversion decreases when the fraction of TBPMI is higher than the equimolar ratio. The thermal stability of the alternating copolymers is higher than that of polystyrene, and their mixture showed appreciable flame-retardant properties, as demonstrated by a limiting oxygen index measurement. 相似文献
50.
We classify finite 2-groupsG possessing an involution which is contained in a unique subgroup of order 4 inG. This answers a question of N. Blackburn about finite 2-groups. We show that the extended Blackburn’s problem is reduced
to the outstanding problem ofp-group theory to classify 2-groups with exactly three involutions. 相似文献