Nachweis von ω-Aminocarbonsäuren und Carbonylverbindungen in thermooxidativ abgebautem Polycaprolactam

After oxidation and subsequent hydrolysis homologous series of alkyl amines and ω-amino carboxylic acids were proved to be further degradation products of polycaprolactam. The formation of these substances cannot be explained by an attack on the N-vicinal methylene group which is the most reactive site of this polymer. Considering the low and nearly equal amount of nitrogen containing degradation products a statistical attack on the remaining methylene groups takes place besides the preferred N-vicinal reaction. The CO-vicinal site is not particularly activated. The formation of likewise isolated substances with carbonyl groups cannot be explained by a uniform mechanism.     

Studies on the role of the preoptic area in the control of reproductive function in the rat

The present study was designed to determine the effects of bilateral lesions restricted to the medial preoptic area on reproductive function in rats. Adult female rats were placed in a stereotaxic instrument, and bilateral lesions were made in the medial preoptic area of the diencephalon using an anodic current and platinum or stainless steel electrodes. Both types of lesions produced identical effects. Most animals with lesions restricted to the medial preoptic area showed repeated periods of pseudopregnancy for the duration of their lives. Ova were detected in the oviducts on the day of estrus between pseudopregnancies, and deciduomata could be produced by uterine traumatization during pseudopregnancy. Daily administration of lergotrile mesylate, a dopamine agonist, for about two weeks, to the pseudopregnant rats with lesions resulted in the appearance of normal 4 or 5-day estrous cycles. These results suggest that the medial preoptic area may not be necessary for ovulation in the rat, and that the normal function of the preoptic area in the control of reproductive cyclicity may be mediated via dopaminergic neurons. In agreement with earlier studies, we found that lesions that extended into the anterior hypothalamus resulted in constant estrus.     

Der Stickstoff der Gasphasen bei den Reaktionen zwischen Eisenschmelzen und Silikatschlacken im Graphittiegel

Hinzutreten des Stickstoffs des Luftgases zu Eisenschmelze und Schlacke im Graphittiegel trotz des Entstehens von Kohlenmonoxyd aus den Reaktionen des Kohlenstoffs. Verschiedene Orte der Reaktionen, zwei Gasphasen. Analytische Bestimmung verschiedener Verbindungen des Stickstoffs in den erstarrten Schlacken. Stickstoffaufnahme durch Eisenschmelzen und CaO-Al₂O₃(10%)-SiO₂- sowie CaO-Al₂O₃(10%)-MgO(10%)-SiO₂-Schlacken verschiedener Basizität bei 1550 °C in 1 h. Einfluß des Mengenverhältnisses von Eisenschmelze und Schlacke auf die Stickstoffaufnahme beider. Wirkung von Flußspatzusätzen, 5% CaF₂, auf die Reaktionen des Stickstoffs bei 0,5 und 2 h Reaktionszeit. Verhalten des Stickstoffs bei und nach dem Speichern der Reduktionswirkung des Kohlenstoffs durch die Schlacke. Nitride und Zyanide als Reduktionsmittel, ein Problem der Kinetik der Bildung von Gasphasen aus Flüssigkeiten. Wirkung des Zusatzes von Eisenoxyden zu stickstoffhaltigen Schlacken.     

Capacitance of MOS diodes on substrates doped non-uniformly near the surface

The usual assumption of uniform doping in the space charge region no longer holds if the doping near the semiconductor surface is changed appreciably by thermal oxidation and/or ion implantation. Poisson's equation becomes the non-linear, but can be solved using suitable approximations for the dependence on the voltage. Thus the exact form of the doping profile is taken into account.The C?V curves of MOS diodes differ considerably from those for uniform doping due to the altered relation between the surface potential and the total charge of the semiconductors as well as due to the altered width of the space charge region. These two contributions are reduced to additive terms if the space charge region covers completely the region with altered doping.For weak depletion the slope of the C?V curves is larger for pile-down of acceptors and pile-up of donors in p-type silicon. The slope becomes smaller for increasing depletion, because the space charge region spreads now to more heavily doped regions of the semiconductor. For pile-up of donors and pile-down of acceptors in n-type silicon, the curves are initially less declined and become steeper according to the smaller doping in the bulk of the semiconductor.     

Lektor-a list-oriented,machine-independent programming system for conversational applications

This paper introduces the machine-independent programming system LEKTOR which has been used for research and developmental work in computer-based learning since the beginning of 1974. The most important language elements and the system architecture are described. Emphasis is placed upon questions of implementation, particularly with regard to the data structures and the organization and administration of the workspace.     

Zum Problem der Datendokumentation

Some problems of numerical data documentation . Central data pools which fulfil most of the requirements of science and practice are both expensive and manpower-intensive because of the vast quantities of data involved, uncertainty regarding material composition, disregarded parameter influences, insufficient reliability, and problems of copyright. A worldwide survey reveals the existence of a wide variety of data pools which are underused because they are not known. The paper cites literature listing such pools. One of the recommendations in the paper is to cooperate in transferring all available data of a material into its “data matrix” – thus exposing the gaps that are still left. This would be a relatively inexpensive step towards improved data supply.     

Die Änderung des Mikrogefüges von warmfesten Stählen durch Zeitstandbeanspruchung

Untersuchung der Gefügeänderungen in Zeitstandproben aus zwölf Laboratoriumsschmelzen mit rd. 0,15% C, 0 bis 2,4% Cr, 0 bis 1,1% Mo bei 550 °C und Laufzeiten bis 16 000 h mit Licht- und Elektronenmikroskop, durch Carbidisolierungen und durch Röntgenbeugung. Wechselwirkung von Chrom und Molybdän auf die Ausscheidungsvorgänge und auf das Zeitstandverhalten.     

Flat-earth guidance law using inflight vehicle parameter identification

This paper describes the formulation and simulation testing of a Flat Earth Guidance Law using a quadratic injection criterion and inflight vehicle parameter identification and updating. It avoids the usual instability close to injection without necessitating a separate injection guidance routine and eliminates the distortion of the attitude law at injection due to vehicle parameter deviations from nominal. It is suited for injection into circular and elliptical orbits. Apart from effectiveness and parameter sensitivity of the guidance law the discussion of results also covers the practical aspects of implementation in and onboard computer with limited resolution accuracy.