The use of microtechniques in the teaching of chemistry

Summary It was pointed out that although small scale experimentation, micromethods, and microtechniques were considered for teaching even at elementary level over 100 years ago, their adoption has been very slow, and to a very large extent they have remained in the realm of the specialist.Though it may appear strange at first sight that there should be reluctance to experiment with methods of teaching science, an area of knowledge whose very heart is continuous experimentation, a small amount of reflection will show that teaching methods are a part of the sum total of the complex called culture which changes only slowly over a period of centuries. There is a definite trend towards the adoption of these methods for teaching chemistry not only at the college level, but also at the intermediate educational level, not alone because of the saving of time and materials but also because micromethods impart superior disciplines.     

On the electron impact induced hydroxyl loss from o-nitrostyrene

Unimolecular hydroxyl (OD^˙) loss from regio- and stereo-specifically labelled o-nitrostyrenes 1a, 1c and 1d results in the formation of an ion which upon collisional activation gives identical mass spectra. Suggestions are made which aim at explaining: (i) the loss of stereochemical integrity of the diastereotopic methylene hydrogens in the course of hydroxyl elimination; and (ii) to account for the collision induced losses of CO and HNC from the [M—hydroxyl]⁺ ion.     

Eine einfache,Fourier-gestützte Methode zur Beseitigung von Untergrund in einzelnen Spektral-Peaks

Analytical and Bioanalytical Chemistry - Durch energiedispersive Röntgenanalyse entstehen Spektren mit hohem Untergrundanteil. Es wurden von einzelnen Peaks die Koeffizienten A und B der...     

The partition function of degenerate quadratic functional and Ray-Singer invariants

The partition function of degenerate quadratic functional is defined and studied. It is shown that analytic torsion and similar invariants can be interpreted as partition functions of quadratic functionals.     

Pilzpigmente. XXV—Massenspektrometrische Untersuchung Polyisoprenoider Ansabenzochinone

The mass spectra of tridentoquinone and its derivatives are characteristically different from those of the biogenetically related boviquinones. The complex fragmentation pattern could be deduced to some extent using high resolution mass spectrometry, the metastable refocusing technique and in the case of secotridentoquinone, labelling of the hydroxyl functions.     

The wavelength sensitivity of back-scattering

The effect of wavelength variations on the backscattering of laser light from contoured or shaped objects is analyzed. In order to consider remote sensing by frequency-scan means, equations are derived for the transforms of the signal field and its intensity and for the correlation functions appropriate in the study of rough objects. In these expressions, interesting dependences upon object shape, roughness, and orientation are found. In experiments using roughened plates and spheres illuminated by a tunable dye laser, good agreement with theory is observed.     

Adiabatic Photoreactions of Organic Molecules

An adiabatic photoreaction is a chemical process that occurs entirely on a single excited electronic energy surface. As a rule, most photoreactions of organic molecules start on an excited electronic surface but “jump” to a lower surface somewhere along the reaction coordinate. There are, however, exceptions to this general rule. For example, photoreactions involving small structural changes and minor alterations in covalent bonding (e.g., proton transfer and complex formation) are commonly found to occur adiabatically. The purpose of this review is to survey examples of more complicated adiabatic photoreactions such as fragmentation, electrocyclic rearrangements, and geometrical isomerizations. The concepts employed are presented in an introductory discussion.