Say It in English,Please!

Robert Schoenfeld, bis zu seiner Pensionierung 1985 ?Managing Editor? des Australian Journal of Chemistry, war zahlreichen Wissenschaftlern – nicht nur englischsprachigen – als Autor von The Chemist's English bekannt. Viele haben seine immer von Freundlichkeit getragene Offenheit, seinen Sinn für Humor sowie seinen tiefen Einblick in das Wechselspiel von Sprache und Wissenschaft sehr geschätzt. Kurz vor seinem Tod am 24. November 1987 begann er eine neue Serie von Artikeln zu schreiben. Mit ?Say It in English, Please!? wollte er Wissenschaftler ansprechen, deren Muttersprache nicht Englisch ist, die aber trotzdem ihre Veröffentlichungen auf Englisch verfassen müssen. Die folgenden neun Artikel hat er noch zu Ende schreiben können. Sie behandeln Probleme, die vor allem deutschsprachige Wissenschaftler betreffen. Nicht starre Regeln wollte er lehren, sondern seine Erfahrungen und Ansichten mitteilen, und sein Hauptziel war immer, Freude am guten Schreiben zu wecken. Bob hätte seine Serie vielleicht so angefangen: ?Diese Artikel überlasse ich der wohlwollenden Beurteilung meiner Leser”?.     

集值序上鞅的若干有关问题

本文研究了连续时间的集值序上鞅,在一定的假设下我们证明了集值序上鞅有ｈ－Ｒｉｅｓｚ分解,然后证明了集值序上鞅的Ｄｏｏｂ－Ｍｅｙｅｒ分解定理。     

Reflections on learning and cognition

The occasion of my 9th ICME—the first being in Berkeley in 1980, the most recent being in Seoul in 2012—provides an opportunity for reflecting on changes in the field over more than 30 years. “Learning and cognition” have a very different meaning now than they did in 1980. I argue that in various ways, the papers in this volume (derived from the ICME 12 Topic Study Group on Learning and Cognition) represent a significant evolution of the field—with mathematical sense making being a central conception, and with the evolution of the very notions of learning and cognition to include embodied, sociocultural, and historical perspectives. In this volume one sees a focus on classroom activities as they engender aspects of sense making, framed in ways that were not even part of the discourse on learning in 1980; one also sees a widely varied set of research methods for addressing such issues. I reflect on the state of the art, and then discuss some possibly productive directions with regard to the characterization and support of mathematically productive classrooms.     

High-performance liquid chromatographic detection of pitfalls in porphobilinogen deaminase determination.

Potential pitfalls in the determination of porphobilinogen deaminase activity, as well as ways of eliminating these sources of error and determining the activity accurately, are discussed. In addition to measurement of the accurate activity, the described method (a combination of incubation of homogenate with porphobilinogen and high-performance liquid chromatographic separation) can also be used to detect enzymic defects in the haem biosynthetic pathway, according to the pattern of accumulation of the various porphyrins.     

Improved control of the phosphorous surface concentration during in‐line diffusion of c‐Si solar cells by APCVD

Emitter formation for industrial crystalline silicon (c‐Si) solar cells is demonstrated by the deposition of phosphorous‐doped silicate glasses (PSG) on p‐type monocrystalline silicon wafers via in‐line atmospheric pressure chemical vapor deposition (APCVD) and subsequent thermal diffusion. Processed wafers with and without the PSG layers have been analysed by SIMS measurements to investigate the depth profiles of the resultant phosphorous emitters. Subsequently, complete solar cells were fabricated using the phosphorous emitters formed by doped silicate glasses to determine the impact of this high‐throughput doping method on cell performance. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Influence of precursor gas ratio and firing on silicon surface passivation by APCVD aluminium oxide

Using a high throughput, in‐line atmosphere chemical vapor deposition (APCVD) tool, we have synthesized amorphous aluminum oxide (AlO_x) films from precursors of trimethyl‐aluminum (TMA) and O₂, yielding a maximum deposition 150 nm min^–1 per wafer. For p‐type crystalline silicon (c‐Si) wafers, excellent surface passivation was achieved with the APCVD AlO_x films, with a best maximum effective surface recombination velocity (S_eff,max) of 8 cm/s following a standard industrial firing step. The findings could be attributed to the existence of large negative charge (Q_f ≈ –3 × 10¹² cm^–2) and low interface defect density (D_it ≈ 4 × 10¹¹ eV^–1 cm^–2) achieved by the films. This data demonstrates a high potential for APCVD AlO_x to be used in high efficiency, low cost industrial solar cells. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of an electric field on the carrier collection efficiency of InAs quantum dots

Individual and multiquantum dots of InAs are studied by means of microphotoluminescence in the case where, in addition to the principal laser exciting photoluminescence, second infrared laser is used. It is demonstrated that the absorption of the infrared photons effectively creates free holes in the sample, which leads to both a change in the charge state of a quantum dot and to a considerable reduction of their photoluminescence signal. The latter effect is explained in terms of effective screening of the internal electric field, facilitating carrier transport along the plane of a wetting layer, by the surplus holes from the infrared laser. It is shown that the effect of quenching of quantum dot photoluminescence gradually disappears at increased sample temperature (T) and/or dot density. This fact is due to the essentially increased value of quantum dot collection efficiency, which could be achieved at elevated sample temperatures for individual quantum dots or even at low T for the case of multiquantum dots. It is suggested that the observed phenomena can be widely used in practice to effectively manipulate the collection efficiency and the charge state of quantum-dot-based optical devices.     

A US perspective on the implementation of inquiry-based learning in mathematics

This paper discusses issues related to the potential adoption of inquiry-based learning (IBL) projects in mathematics in the United States. To explain the challenges faced in making a place for IBL in the mathematics curriculum, we describe the historical demands of working with a diverse, highly distributed educational system (that is, a system that does not have a central educational decision-making agency with the authority to mandate nation-wide changes), the impact of high-stakes tests to either open or limit the potential for curricular changes, and the changing context in the United States owing to the emergence of the Common Core State Standards in Mathematics (CCSS-M) and nationwide high-stakes assessments designed to be consistent with the CCSS-M. We identify a number of dimensions along which there would be challenges for the implementation of IBL in US school mathematics, including: perceived societal needs; schooling traditions; the specific framing of CCSS-M goals pertaining to problem solving, communicating and reasoning, and modeling and data analysis; and the readiness of the US teaching force to implement IBL. We then consider the issue of scaling up interventions such as IBL, and the politics involved therein.