Helmut Beckmann (1940–2006)

Cyclopropenium ion catalysed Beckmann rearrangement.

1-Chloro-2,3-diphenylcyclopropenium ion was found to be a very efficient organocatalyst (3 mol% loading) for liquid phase Beckmann rearrangement of various ketoximes to the corresponding amides/lactams within 2 h in acetonitrile at reflux temperature. This is the first example of the application of the cyclopropenium ion as a catalyst, which opens up a new aspect of the synthetic utility of aro...

What is ERP ? Helmut

Though enterprise resource planning (ERP) has gained some prominence in the information systems (IS) literature over the past few years and is a signi®cant phenomenon in practice, through (a) historical analysis, (b) meta-analysis of representative IS literature, and (c) a survey of academic experts, we reveal dissenting views on the phenomenon. Given this diversity of perspectives, it is unlik...

Redox pioneer: professor Helmut Sies.

Dr. Helmut Sies (MD, 1967) is recognized as a Redox Pioneer, because he authored five articles on oxidative stress, lycopene, and glutathione, each of which has been cited more than 1000 times, and coauthored an article on hydroperoxide metabolism in mammalian systems cited more than 5000 times (Google Scholar). He obtained preclinical education at the University of Tübingen and the University ...

Helmut Hasse Lectures on Class Field Theory

Fresnel Correction of the Beckmann Model

In this paper we suggest a modification to the Beckmann-Kirchhoff model of rough surface reflectance that can be used for surfaces of intermediate roughness. One of the problems with the existing Beckmann model is that it fails for large angles of incidence. This problem was overcome for rough surfaces by Vernold and Harvey who use a Lambertian form factor. Here we take this work one step furth...