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21.
Zusammenfassung Der Einfluß von Fangstellen für Wasserstoff auf die Wasserstoffdurchlässigkeit kaltgewalzter Stähle wurde untersucht. Dabei konnte gezeigt werden, daß sowohl der Gesamtgehalt an Schwefel und Sauerstoff als auch die Verteilung der Sulfide bedeutenden Einfluß auf die Wasserstoffdurchlässigkeit ausüben.
Vortrag, gehalten beim 9. Kolloquium über Metallkundliche Analyse, Wien, 23. bis 24. Oktober 1978. 相似文献
The determination of sulfides in cold-working steels with reference to the hydrogen permeability
Summary The influence of traps for hydrogen on the hydrogen permeability of cold-working steels was investigated. It was shown that the total content of sulfur and oxygen and the distribution of the sulfides are of significant importance for the hydrogen permeability.
Vortrag, gehalten beim 9. Kolloquium über Metallkundliche Analyse, Wien, 23. bis 24. Oktober 1978. 相似文献
22.
Theoretical study of the adsorption of 0.75 and 1 monolayer of F, Cl, and I on the Ge(0 0 1)-p(1×2) surface is presented. Various stable atomic configurations are considered, their surface electronic properties are discussed by means of the density-of-states analysis, and the corresponding STM images are simulated. While the results obtained for Cl and I are similar to those known for Br, the F-covered surfaces exhibit noticeably different features. 相似文献
23.
The Model of “Minimal Oscillator” Derived from the Kinetic Mechanism of the H2O2–NaSCN–NaOH–CuSO4 Dynamical System
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Dissipative chemical reactions, which involve oscillatory variations of the concentrations of the intermediates in time, are usually characterized with complicated kinetic mechanisms. However, the essential source of the oscillations can often be reduced to only a few reaction steps providing the alternative domination of the positive and negative feedback loops. In an extreme case such a reduction leads to the so–called “minimal oscillator,” the concept used in the past for the well‐known Belousov‐Zhabotinsky (BZ) reaction. In the present work, we construct such a minimal system for the (discovered by M. Orbán) H2O2–NaSCN–NaOH–CuSO4 homogeneous oscillator, in which instabilities originate from kinetic mechanism substantially different from that proposed for the BZ system. The methodology involves intuitive analysis of the reaction mechanism, supported by numerical calculations and spectrophotometric measurements. We show how the actual, only three‐variable model evolves from our previously elaborated: nine‐ and five–variable mechanisms and prove that its further reduction to two–variable one is not possible. Thus the present work is a final step in our searches for the “minimal Orbán oscillator”. 相似文献
24.
Zbigniew Ciunik Krzysztof Drabent Mikołaj F. Rudolf 《Journal of chemical crystallography》1994,24(8):507-510
The synthesis and crystal structure of 1,4-S,S-isothiosemicarbazidebutane dihydrobromide have been presented. The crystals are monoclinic:P21/n, a=7.9910(10),b=10.979(2),c=8.9240(10)Å, =111.450(10)°,Z=2, room temp. The structure was solved by direct methods. and refined to R=0.0297 for 846 reflections. The title compound consists of the centrosymmetric [C6H18N6S2]2+ dication and two Br– anions. Intramolecular N–H...N and intermolecular N–H...Br hydrogen bonds stabilizetrans conformation of the thiosemicarbazide moiety. 相似文献
25.
Arkadiusz Józefczak Tomasz Hornowski Miko?aj ?abowski Peter Kop?anský Andrzej Szlaferek 《Journal of magnetism and magnetic materials》2009,321(10):1505-1508
The aim of this study was to investigate the influence of poly(ethylene glycol) surface-active coating on the magnetic and thermal properties of biocompatible magnetic liquids. The data were analyzed using the high-temperature approximation model taking into account polydispersity of a system. Heating ability of the PEG-stabilized magnetic fluids was determined by the calorimetric measurement of specific absorption rate (SAR) at a frequency of 750 kHz and a magnetic field of 0-2 kA/m. MF-Oleate/PEG heating properties were found to be comparable to the ones of MF-Oleate. The PEG shell thus does not seem to effect the thermal characteristics and SAR values and might make the magnetic fluid useful for application in hyperthermia treatment. 相似文献
26.
K. Hackiewicz P. Martyniuk J. Rutkowski T. Manyk J. Mikołajczyk 《Opto-Electronics Review》2018,26(4):279-284
The utmost limit performance of interband cascade detectors optimized for the longwave range of infrared radiation is investigated in this work. Currently, materials from the III–V group are characterized by short carrier lifetimes limited by Shockley-Read-Hall generation and recombination processes. The maximum carrier lifetime values reported at 77 K for the type-II superlattices InAs/GaSb and InAs/InAsSb in a longwave range correspond to ~200 and ~400 ns. We estimated theoretical detectivity of interband cascade detectors assuming above carrier lifetimes and a value of ~1–50 μs reported for a well-known HgCdTe material. It has been shown that for room temperature the limit value of detctivity is of ~3–4×1010 cmHz1/2/W for the optimized detector operating at the wavelength range ~10 μm could be reached. 相似文献
27.
Dr. Marta E. Plonska‐Brzezinska Dr. Mikołaj Lewandowski Dr. Małgorzata Błaszyk Dr. Agustin Molina‐Ontoria Prof. Dr. Tadeusz Luciński Prof. Dr. Luis Echegoyen 《Chemphyschem》2012,13(18):4134-4141
Composites of unmodified or oxidized carbon nano‐onions (CNOs/ox‐CNOs) with poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are prepared with different compositions. By varying the ratio of PEDOT:PSS relative to CNOs, CNO/PEDOT:PSS composites with various PEDOT:PSS loadings are obtained and the corresponding film properties are studied as a function of the polymer. X‐ray photoelectron spectroscopy characterization is performed for pristine and ox‐CNO samples. The composites are characterized by scanning and transmission electron microscopy and differential scanning calorimetry studies. The electrochemical properties of the nanocomposites are determined and compared. Doping the composites with carbon nanostructures significantly increases their mechanical and electrochemical stabilities. A comparison of the results shows that CNOs dispersed in the polymer matrices increase the capacitance of the CNO/PEDOT:PSS and ox‐CNO/PEDOT:PSS composites. 相似文献
28.
29.
A fully stereoselective synthesis of both enantiomers of 2-oxo-2-thio-1,3,2-oxazaphosphorinanyl salt has been accomplished in five steps with an overall 40–45% yield starting from the diastereoisomeric N-methylstrychninium salts of methyl p-nitrophenyl phosphorothioic acid. Their conversion to the enantiomeric forms of methyl p-nitrophenyl phosphorochloridothionate as a two-step phosphorylating agent allowed the formation of the 1,3,2-oxazaphosphorinane ring in this reaction sequence. An alternative four-step approach to the enantiopure title salt was developed which involves in the first and crucial step cyclocondensation between thiophosphoryl chloride and N-α-naphthylethyl containing a 1,3-aminopropanol group, occurring with almost complete diastereoselectivity. 相似文献
30.
The paper is devoted to a monosymetrical cold-formed thin-walled beam with open cross section. Its flange consists of plates and circular shells. The beam is under pure bending. The cross section is characterized by dimensionless parameters. The authors are searching for an optimal cross section shape of considered beam. This optimal shape is determined by means of parametric optimization. The dimensionless objective function is so defined as to comprise both cross section area and a maximal allowable bending moment. The constraints follow from the local buckling conditions and geometric restrictions. Moreover, there are optimized cross sections of beams, for which the shear center is located either in the web or in the centroid of the cross section. Results are compared and analyzed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献