Comments on “measurement of the absorption coefficients for the He−Ne laser radiation in a pure hydrogen plasma”

Applied Physics A - In a recent publication in this journal, Öke described an experiment designed to measure the total absorption coefficients for 0.6328- and 1.15-μm He?Ne laser...     

Collisionless dissociation and isotopic enrichment of SF6 using high-powered CO2 laser radiation

Dissociation of ³²SF₆ and the resultant isotopic enrichment of ³⁴SF₆ using high-powered CO₂ laser radiation has been studied with higher experimental sensitivity than previously reported. Enrichment factors have been measured as a function of laser pulse number, wavelength, energy and time duration. A geometry-independent dissociation cross section is introduced and measured values are presented. Threshold energy densities, below which no dissociation was observed, were also determined.     

Does the chalkboard still hold its own against modern technology in teaching mathematics? A case study

The purpose of this case study is to explore the integration of technology into teaching at a mathematics department at a large South African University. Both quantitative and qualitative data were collected from staff teaching undergraduate mathematics. The study shows that many staff members feel that chalkboards are still more suitable than technology for teaching mathematics. This finding supports the idea of a strong subject culture. Age does not emerge as a determinant for preference of either technology or the chalkboard, although gender and academic qualifications do. Subject culture is strongly rooted under the male members of staff, while female staff members feel more positive towards the use of technology in teaching. Use of chalkboards has decreased significantly over the past 10 years, while the use of modern technologies has increased accordingly. Teaching of large groups has necessitated the use of technology in the classroom. Despite the strong subject culture, a shift in attitude towards technology use in teaching is noticed and there is a definite trend of moving towards using new technologies.     

A New Procedure for the Conversion of Cinnamaldehydes to Hydrocinnamaldehydes

In connection with some of our reserch we were interested in preparing various substituted hydrocinnamaldhydes. The easiest approach seemed to be the reduction of the olefinic bond of the corresponding substituted cimamaldenyde. It was found that the selective reduction of aromatic α,β-unsaturated aldehydes present many difficulties because the olefinic bond and carbonyl groups are both easily reduced. The absorption of one equivalent of hydrogen by cinnamaldehyde can produce hydrocinnamaldehyde by the reduction of the olefinic bond, cinnamy1 alcohol by reduction of the carbony1 group,and hydrocinnamy1 alcohol by reduction of both the olefinic bond and carbony1 group. Various hydrogenolysis products can also be formed in lesser yields.