Neue Azoolefine und deren saure Spaltung zu Aryldiiminen

New Azoolefines and their Acidic cleavage to Aryldiimines 3-Amino-1-aryl-3′,3′-dimethyl-pyrazolin-4-spiro-2′-oxiran-5-ones ( 3a – c ) undergo ring opening with methoxide forming methyl 3-amino-3-arylazo-propenoates ( 5a – c ). 5a – c are cleaved under acidic conditions. The main products of the cleavage of 5c with methanolic hydrochloric acid are nitrogen, 2, 4, 6-trichloro-benzen ( 6 ), 2, 4, 6-trichloro-aniline ( 9 ) and 2, 4, 6-trichlorophenylhydrazine ( 10 ). Intermediates of the cleavage of 5 are aryldiimines trapped with benzaldehyde as the corresponding benzhydrazides ( 12a , b ).     

Wasserstoffinduzierte Spannungsrißkorrosion an unverzinkten und verzinkten Baustählen

Hydrogen induced stress corrosion cracking of non galvanized and galvanized construction steels The processes of atmospheric corrosion and corrosion in collected water which may lead to hydrogen induced stress corrosion cracking of high-strength reinforcing steels in casing tubes before injection with concrete are discussed. Hydrogen uptake during corrosion occurs in weakly acid solutions as well as in neutral or alkaline aqueous solutions. The hydrogen uptake by proton discharge in acid solutions decreases with increasing pH of the electrolyte. Hydrogen can also be absorbed in neutral to weakly alkaline solutions if steels are plastically deformed and water reacts with the fresh iron surface. In alkaline solutions, hydrogen uptake is possible if, at the generally passivated steel surface, localized corrosion (pitting or crevice corrosion), local galvanic cells and a sufficient decrease in the pH of the pit electrolyte occurs. In the case of galvanized steels with damaged zinc layers, hydrogen uptake may result from the cathodic polarization of the free steel surface by zinc dissolution. The absorbed hydrogen interacts with the microstructure of the steels and weakens the bonds between the iron atoms. The influence of the microstructure of high-strength steels on the fracture behaviour is discussed on the basic of the so-called decohesion theory.     

Anionic and nonionic surfactant sorption and degradation by algae cultures

Degradation of three surfactants has been determined by organic extraction procedures and infrared spectroscopy. Axenic cultures of five species of blue-green algae and three species of green algae which are common to waste stabilization ponds were test organisms. Analytical data are shown comparing the effects produced by the algae cultures and a heterogeneous microcosm. Linear alkyl sulfonate was the anionic surfactant compound tested. An alkyl polyethoxylate and an alkyl phenol polyethoxylate were the nonionic test surfactants. Sorption of the compounds by the algae usually was followed by release and degradation of up to 99% of some of the component parts of the surfactant molecule.     

Age and epogenic influences on aspirations of minority and majority group children.

Investigated the educational, financial, and occupational aspirations of 48 Anglo-American, 56 Mexican-American, and 55 Negro 12-15 yr olds, using a combination of a cross-sectional approach, a repeated measures design with matched groups, and a longitudinal approach. Ss completed an open-ended and multiple-choice aspiration questionnaire in l967 and in l970. The expectations of the Mexican-Americans were the lowest in the l967 administration, and those of the Anglo-Americans were the highest. In 1970, expectations of the minority groups had increased and those of the Anglo-Americans had decreased due to epogenic influences (e.g., the La Raza or the Black Power movements). In the longitudinal study, aspirations of the Anglos were stable, while the aspirations of the minority group members declined. The counteracting effects of S's increasing age and epogenic influences are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrical conduction phenomena in thin tetracene films

Thin film aluminium oxide capacitors using anodic Al₂O₃ as the dielectric are described. The dependence of oxide thickness and dielectric loss on anodization voltage was studied. Variation of capacitance with temperature and frequency was also investigated. The capacitors were used in conjunction with tantalum resistors to fabricate an astable multivibrator circuit and the waveforms were recorded. The combination of aluminium oxide capacitors and tantalum resistors has some advantages over all-tantalum RC networks.     

Improving generalization capabilities of dynamic neural networks

This work addresses the problem of improving the generalization capabilities of continuous recurrent neural networks. The learning task is transformed into an optimal control framework in which the weights and the initial network state are treated as unknown controls. A new learning algorithm based on a variational formulation of Pontrayagin's maximum principle is proposed. Under reasonable assumptions, its convergence is discussed. Numerical examples are given that demonstrate an essential improvement of generalization capabilities after the learning process of a dynamic network.