Wein

Ohne Zusammenfassung     

Polarographische Untersuchungen an 1,3-Thiazinthionen

Polarographic Investigations of 1,3-Thiazinthiones 1,3-Thiazine-6-thiones are stepwise reduced in aprotic media to the corresponding radical anions and dianions. In the case of the 2,4-diphenyl derivative ( 1a ) the radical anion is stable in dimethylformamide, whereas the dianion reacts further to yield the bithiazinylidene ( 4 ) among other products. The effect of substituents on the reduction potentials is discussed.     

Gas–Solid Interactions During Nonisothermal Heat Treatment of a High-Strength CrMnCN Austenitic Steel Powder: Influence of Atmospheric Conditions and Heating Rate on the Densification Behavior

This work deals with gas?Csolid interactions between a high-alloyed steel powder and the surrounding atmosphere during continuous heating. It is motivated by the recently developed corrosion-resistant CrMnCN austenitic cast steels. Here, powder metallurgical processing would be desirable to manufacture highly homogeneous parts and/or novel corrosion-resistant metal-matrix composites. However, the successful use of this new production route calls for a comprehensive investigation of interactions between the sintering atmosphere and the metallic powder to prevent undesirable changes to the chemical composition, e.g., degassing of nitrogen or evaporation of manganese. In this study, dilatometric measurements combined with residual gas analysis, high-temperature X-ray diffraction (XRD) measurements, and thermodynamic equilibrium calculations provided detailed information about the influence of different atmospheric conditions on the microstructure, constitution, and densification behavior of a gas-atomized CrMnCN steel powder during continuous heating. Intensive desorption of nitrogen led to the conclusion that a vacuum atmosphere is not suitable for powder metallurgical (PM) processing. Exposure to an N₂-containing atmosphere resulted in the formation of nitrides and lattice expansion. Experimental findings have shown that the N content can be controlled by the nitrogen partial pressure. Furthermore, the reduction of surface oxides because of a carbothermal reaction at elevated temperatures and the resulting enhancement of the powder??s densification behavior are discussed in this work.     

Weizen w?hrend der Reifung

Zusammenfassung In Fortführung einer früheren Arbeit über chemische Veränderungen der Weizensorte Schirokko während der Reifung [1] wurden die Gliadine und Glutenine mit Hilfe der RP-HPLC näher untersucht. Für die Gliadinfraktion konnte gezeigt werden, daß im Reifungsverlauf die-Gliadine zuerst und die-Gliadine zuletzt auftreten. Zur Entwicklung des reifen, stark differenzierten-Gliadinmusters wird ein relativ langer Zeitraum von ca. vier Wochen nach der Blüte benötigt. Die Chromatogramme der Gluteninfraktion zeigen bei den HMW-Untereinheiten nur qualitative Unterschiede, während bei den LMW-Untereinheiten eine stärkere Differenzierung im Laufe der Reifung zu beobachten ist. Der Anteil der HMW-Untereinheiten am Gesamtglutenin nimmt von ca. 15% auf ca. 30% zu und der der LMW-Untereinheiten von ca. 75% auf ca. 60% ab. Die MMW-Fraktion bleibt mit ca. 10% relativ konstant. Innerhalb der HMW-Fraktion kommt es infolge unterschiedlicher Zunahme der einzelnen Komponenten zu stärkeren Verschiebungen. Während in frühen Reifungsstadien die HMW-Untereinheiten 3 und 10 deutlich stärker vertreten sind als die Untereinheiten 5, 1 und 9 (Bezeichnung entsprechend [2]), dominiert in reifem Schirokko die Untereinheit 5, gefolgt von den Komponenten 3 und 10, während die Untereinheiten 1 und 9 in deutlich geringerer Menge vertreten sind.

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Wheat during maturation: analysis of gliadins and glutenins by RP-HPLC

Summary In continuation of a study of changes in the chemical composition of the wheat variety Schirokko during ripening [Kieffer R et al. (1988) Z Lebensm Unters Forsch 187:339], the gliadins and glutenins were investigated in more detail by RP-HPLC. The chromatograms of the gliadin fraction show very clearly that the-gliadins appear first and the-gliadins last during the ripening process. A relatively long period of about four weeks after flowering is necessary for the development of the ripe, strongly differentiated,-gliadin pattern. The chromatograms of the glutenins exhibit only qualitative changes in the high-molecular-weight subunits during maturation, while the low-molecular-weight subunits show an increasing differentiation, similar to the gliadins. The proportion of high-molecular-weight subunits increases from about 15% to 30% of whole glutenin, while the low-molecular-weight subunits decrease from about 75% to 60%. The medium-molecular-weight subunits remain relatively constant in the range of 10%. Remarkable quantitative shifts between high-molecular-weight glutenins were observed during ripening. While subunits 3 and 10 [nomenclature according to Krause I et al. (1988) Z Lebensm Unters Forsch 186:398] dominate the pattern in early stages, large amounts of subunit 5, followed by decreasing amounts of subunits 3 and 10 and, after longer tires, subunits 1 and 9 are characteristic for ripe Schirokko.

     

Multicomponent Physical Vapor Deposited Films with Homogeneous Molecular Material Distribution Featuring Improved Resist Sensitivity

Each film preparation technique affects the physical properties of the resulting coating and thus defines its applicability in modern device construction. In this context solvent based spin coated and solvent‐free physical vapor deposited molecular glass photoresist films are systematically investigated for their dissolution behavior, sensitivity, and overall lithographic performance. These investigations demonstrate that the solvent‐free physical vapor deposition leads to a marked increase in sensitivity. This could be explained by the individual molecule by molecule deposition step producing a more homogeneous distribution of the multicomponent resist system, especially the photoacid generator. In addition, this assumption is supported by former published simulations focusing on aggregate formation within thin films. This work demonstrates that the lithographic sensitivity of multicomponent resist system is an intrinsic parameter to investigate molecular material distribution and indicates that the applied film preparation technique is crucial for the corresponding performance and applicability.