Correlations between fission fragments for 172 MeV20Ne+197Au: A case study for incomplete fusion

Angular and energy correlations have been measured for coincident fission-fragment pairs from the reaction of¹⁹⁷Au with 8.6 MeV/u²⁰Ne. These data have been analyzed to test for fission after incomplete fusion and its admixture with fission generally attributed to the relatively pure compound-nucleus mechanism. A Monte Carlo kinematic simulation program has been written to provide a basis for detailed comparisons of the experimental data to the calculations that employ various mechanistic assumptions. We conclude that incomplete fusion is indeed a prominent precursor to fission even for incident energies of less than 10 MeV/u. Similar data from earlier studies have been reanalyzed and shown to be consistent with this conclusion.     

A new general method of α-amino-alkylation

N-(1-p-Toluenesulphonyl-alkyl) amides, which are readily prepared from a aldehyde, an amide and sodium p-toluenesulphinate, are versatile α-amido-alkylating agents for sulphur nitrogen and carbon nucleophiles.     

On the estimation of entropy

Motivated by recent work of Joe (1989,Ann. Inst. Statist. Math.,41, 683–697), we introduce estimators of entropy and describe their properties. We study the effects of tail behaviour, distribution smoothness and dimensionality on convergence properties. In particular, we argue that root-n consistency of entropy estimation requires appropriate assumptions about each of these three features. Our estimators are different from Joe's, and may be computed without numerical integration, but it can be shown that the same interaction of tail behaviour, smoothness and dimensionality also determines the convergence rate of Joe's estimator. We study both histogram and kernel estimators of entropy, and in each case suggest empirical methods for choosing the smoothing parameter.     

Synthesis of bifunctional monodisperse poly(N-isovaleryl ethyleneimine)

A bifunctional initiator, ethanediyl 1,2-bis(2-isobutyl oxazolinium trifluoromethane sulfonate) was prepared and used for the ring opening polymerization of 2-isobutyl oxazoline. Polymerizations were run in CH₃CN at 80 and 60°C and in sulfolane at 80°C. The molecular weight distributions of the poly(N-isovaleryl ethyleneimine)s produced, M/I ≤ 45, approached Poisson distribution.