Showing papers by "Technische Universität Darmstadt published in 1981"
TL;DR: In this paper, the upper and lower cross sections of some Cm and Cf isotopes and of Am fission isomers were determined, within the half-life range from 1 ms to 1 year.
Abstract: Superheavy elements (SHE) might be formed via a reaction mechanism called “fusion after instantaneous fission”, which is supposed to occur during the collision of a deformed very heavy nucleus with a spherical one. We bombarded natural uranium targets with lead ions and searched for alpha-emitting and spontaneously fissioning reaction products. Different techniques were used: a rotating wheel, a gas jet system and a radiochemical procedure. No SHE have been found. The upper cross section limits are between 10−33 cm2 and 10−34 cm2 within the half-life range from 1 ms to 1 year. In addition, the production cross sections of some Cm and Cf isotopes and of Am fission isomers were determined.
11 citations
01 Jan 1981
TL;DR: The history of organic electrochemical synthesis goes back to the earlier days of electrochemistry as discussed by the authors, as early as 1834 Faraday described the anodic conversion of acetate anions to CO2.
Abstract: The history of organic electrochemical synthesis goes back to the earlier days of electrochemistry. As early as 1834 Faraday described the anodic conversion of acetate anions to CO2.(1)
10 citations
TL;DR: Experimental information gained in recent years on dissipative collisions is reviewed in this article, where particular attention is devoted to the derivation of an average interaction time, to the initial stage of the collision and to the mass equilibration after capture.
9 citations
TL;DR: In this paper, the authors present a drastic effect in the cross section of high energy target fragments caused by a possible density isomer in the nuclear equation of state (EOS).
Abstract: We present a drastic effect in the cross section of high energy target fragments caused by a possible density isomer in the nuclear equation of state. The fluid dynamical model used here contains dissipative processes such as shear viscosity and heat conduction as well as a thermodynamic evaporation model at a late stage of the nuclear collision. In our calculations we consider as an example the reaction Ne+U at an impact parameterb=4 fm.
4 citations
TL;DR: Computer programs are described that direct the collection, processing, and graphical display of numerical data obtained from high resolution thermal denaturation and circular dichroism studies.
Abstract: Computer programs are described that direct the collection, processing, and graphical display of numerical data obtained from high resolution thermal denaturation (1-3) and circular dichroism (4) studies. Besides these specific applications, the programs may also be useful, either directly or as programming models, in other types of spectrophotometric studies employing computers, programming languages, or instruments similar to those described here (see Materials and Methods).
2 citations
01 Jan 1981
TL;DR: In this paper, the authors used the cross-sections observed in Coulomb excitation measurements to determine electromagnetic properties of the nuclear states involved in the excitation process, which is a very clean and well determined way for producing nuclei in excited states.
Abstract: Nuclear Coulomb excitation, that is the excitation of a nucleus via the electromagnetic field produced by another, swiftly passing nucleus, has been a very important tool in nuclear spectroscopy ever since the first Coulomb excitation experiment had been performed by T. Huus and C. Zupancic in the early fifties1. The fruitfulness of Coulomb excitation for the study of the properties of excited nuclear states is mainly due to two reasons: (i) As long as the two colliding nuclei remain well outside the range of the nuclear forces, the interaction between the two nuclei can be assumed to be purely electromagnetic. Thus the excitation process itself is theoretically well understood, in contrast to most production processes involving nuclear forces. Consequently, the cross-sections observed in Coulomb excitation measurements can be solely used to determine electromagnetic properties of the nuclear states involved in the excitation process. (ii) Coulomb excitation, on the other hand, provides also a very clean and well determined way for producing nuclei in excited states. Thus the application of standard in-beam γ-spectroscopic techniques as e.g. the Recoil-Distance, the Doppler-Shift-Attenuation and the Perturbed-Angular-Correlation methods developed to study specific properties of excited states, is very often simplified significantly by using Coulomb excitation to prepare the ensemble of excited nuclei.