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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 16 (1981), S. 2590-2596 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effect of Cr, Ni, Mo, Si and Cu on the diffusivity of hydrogen inα-iron is studied in the temperature range of 160 to 430° C at a hydrogen pressure of 1 atm. The diffusivity of hydrogen was determined by absorption rate experiments using Sievert's type apparatus. The results show that the diffusivity of hydrogen in iron alloys decreases and the activation energy increases, as the concentration of the alloying elements increases, except Cu and Ni. The trapping parameters of hydrogen in iron alloys on the basis of Oriani's approach are calculated. The results show that Si, Mo and Cr are in order of increasing trap energy and that Cu and Ni have a negligible effect on hydrogen trapping. This can be explained by taking account of both chemical affinity effects and elastic strain effects of alloying elements on hydrogen trapping.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 19 (1984), S. 1428-1438 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Dislocation dynamics in MgO single crystals is studied by means of plate impact experiments in which specimens are subjected to stress pulses of 214 to 376 MPa resolved shear stress with duration in the range of 0.09 to 0.23μsec. Dislocation structures in the recovered crystals are observed by an etch pit technique and by transmission electron microscopy. Etch pit studies show that inclusions play a role in the generation of interior glide bands and that there is a 20 to 40-fold increase in dislocation densities outside the glide bands. Assuming the average dislocation velocity is approximately proportional to the applied stress the drag coefficient for MgO at dislocation velocities of 1 to 2 km sec−1 is observed to be 5×10−5 Nsec m−2. Transmission electron microscopy determines the spacing and curvature of dislocations in glide bands.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 5 (1982), S. 571-571 
    ISSN: 0935-6304
    Keywords: Capillary, Glass, Nylon, Teflon, Fused silica ; Static coating ; Sealing, In-place solidification ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 15 (1982), S. 559-563 
    ISSN: 1612-1112
    Keywords: Gas co-distillation ; Tobacco essential oil ; Splitless injection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The essential oils have been isolated from tobacco leaves using a simple gas co-distillation apparatus. The method involves co-distillation with water under the continuous stream of an inert gas with subsequent single solvent extraction of the distillate. The extract is analysed on GC and GC/MS in splitless injection mode without further concentration. The method was evaluated for reproducibility using n-octadecane as an internal standard. The distillation-extraction procedure was reporducible with an average deviation of ±3% for the major constituents. The present method was applied to the analyses of the essential oils of other agricultural products.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 261 (1983), S. 591-599 
    ISSN: 1435-1536
    Keywords: Copoly (N 5-ω-hydroxyalkyl-L-glutamine-L-glutamic acid) ; Solvent-induced conformational change ; pH-induced conformational change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Copoly (α-amino acid)s consisting ofL-glutamic acid residue andN 5-ω hydroxyalkyl-L-glutamine residue, i.e., 2-hydroxyethyl, 3-hydroxypropyl, and di-2-hydroxyethyl derivatives were prepared by the reactions of copoly (L-glutamic acid) containing succinimide ester with corresponding amino alcohols. The conformation of these copolymers was examined by the CD and infrared measurements. These three copolymers containing about 20–30% hydroxyalkyl groups undergo a methanol-induced and a pH-induced conformational transitions. The copolymer containing about 50% 3-hydroxypropyl group assumes the α-helical conformation in the pH region from 2.5 to 11.6, and in a methanol-water mixture (9∶1). On the other hand, the copolymer containing about 60% di-2-hydroxyethyl groups does not allow any helical conformation even at lower pH and also even in a trifluoroethanol-water mixture (9∶1), suggesting that the branched hydroxyalkyl group is unfavorable for the formation of α-helix. Furthermore, the poly(N 5-di-2-hydroxyethyl-L-glutamine) is shown to have a rather disordered structure in the solid state.
    Type of Medium: Electronic Resource
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