Elektrochemische Charakterisierung von Phosphatschichten auf verzinktem Stahl

Electrochemical characterization of phosphate layers on zinc coated steel The electrochemical test for determination of the coverage of phosphated steel [1] is transferred to zinc coated steel. Potentiodynamic current and capacity measurements as well as impedance spectroscopy were used to evaluate the coverage. For electrogalvanized steel the free metal area decreases to 20% within 60 s phosphating time. The layer growth kinetics are determined for different systems by gravimetric measurements. Time dependent measurement of the potential shows a nickel cementation during trication phosphating. The combination of electrochemical methods and XPS-/EDX-measurements shows the incorporation of manganese and nickel from the trication bath into the phosphate layer. Inhibiting passive layers of aluminium and lead were also detected. The influence of iron originating from the alloy layer on galvannealed steel on the phosphating process is examined.     

Psychological aspects of predictive genetic diagnosis in breast and ovarian carcinoma

Mutations on the genes BRCA1 and BRCA2, that predispose women to breast and ovarian cancer were localised in 1990 (Hall et al. 1990, Narod et al. 1991). With the improvement of the test procedures questions concerning the pros and cons of genetic diagnostic are growing in importance, especially because there are only few scientific studies on the social and psychological consequences of this development. In this article the demands to be made on genetic counselling, the present practice of tests employed in Germany and some "typical" problems of the decision and the consequences of the tests are described.     

Creation of multiple nanodots by single ions

In the search to develop tools that are able to modify surfaces on the nanometre scale, the use of heavy ions with energies of several tens of MeV is becoming more attractive. Low-energy ions are mostly stopped by nuclei, which causes the energy to be dissipated over a large volume. In the high-energy regime, however, the ions are stopped by electronic excitations, and the extremely local (approximately 10 nm3) nature of the energy deposition leads to the creation of nanosized 'hillocks' or nanodots under normal incidence. Usually, each nanodot results from the impact of a single ion, and the dots are randomly distributed. Here we demonstrate that multiple, equally spaced dots, each separated by a few tens of nanometres, can be created if a single high-energy xenon ion strikes the surface at a grazing angle. By varying this angle, the number of dots, as well as their spacing, can be controlled.     

The introduction of elastomeric behavior into polycarboranylenesiloxane SiB-1 polymers from the closo-carborane C2B5H7

The copolymerization of a small amount of the larger (C₂B₈ and C₂B₁₀) carboranes with the smaller C₂B₅ carborane resulted in the formation of an elastomeric SiB-1 carboranesiloxane, a polymer hitherto prepared only in crystalline form. Although the elastomeric behavior of the uncured SiB-1 copolymer decreased with time, curing stabilized the rubber by inhibiting crystallization.     

Computer programs supporting qualitative research

Computer programs to aid qualitative research are offered in increasing numbers. Most programs provide basic features like the decomposition of large bodies of text, labelling of text units by category names, retrieval and search for key words. More advanced features are graphical displays of the categories, secondary texts, statistical output and a multi-user interface. The benefits and dangers of these programs for the process of doing qualitative research are discussed.     

Teachers' occupational well-being and quality of instruction: The important role of self-regulatory patterns.

Teachers' occupational well-being (level of emotional exhaustion and job satisfaction) and quality of instruction are two key aspects of research on teaching that have rarely been studied together. The role of occupational engagement and resilience as two important work-related self-regulatory dimensions that predict occupational well-being and teachers' instructional performance in the classroom was investigated. In Part 1 of the study, self-regulatory data from 1,789 German mathematics teachers were subjected to a latent profile analysis, yielding four self-regulatory types (healthy-ambitious, unambitious, excessively ambitious, and resigned) that differed significantly on emotional exhaustion and job satisfaction. In Part 2, the association between teachers' self-regulatory type and instructional performance was examined in a subsample of 318 teachers. Results showed that teachers' self-regulatory type predicted the quality of instruction in three of the four aspects of instructional performance examined. Moreover, teachers' self-regulatory type was systematically linked to differences in students' motivation. No association was found between teacher self-regulation and student achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)