Ultra high resolution stepper motors design, development, performance and application

The design and development of stepper motors with steps in the 10 arc sec to 2 arc min range is described. Some of the problem areas, e.g. rotor suspension, tribology aspects and environmental conditions are covered. A summary of achieved test results and the employment in different mechanisms already developed and tested is presented to give some examples of the possible use of this interesting device. Adaptations to military and commercial requirements are proposed and show the wide range of possible applications

Performance of CAM based Safety Applications using ITS-G5A MAC in High Dense Scenarios

ETSI ITS-G5 is the current vehicle-to-vehicle communication technology in Europe, which will be standardized by ETSI TC ITS. It is based on IEEE 802.11p and therefore uses a CSMA/CA scheme for Media Access Control (MAC). In this paper we analyze the performance of CAM based safety applications using the ETSI ITS-G5 MAC technology in a challenging scenario with respect to MAC issues: A suitable freeway segment with 6 lanes in each direction. The freeway scenario is thoroughly modeled and implemented in the well known ns-3 simulation environment. Based on this model, the paper shows the performance of CAM based safety applications under MAC challenging conditions. Therefore we provide a set of simulation results resting upon a particular performance metric which incorporates the key requirements of safety applications. Finally we analyze two concrete example scenarios to make a point how reliable CAM based safety applications are in high dense traffic scenarios

Towards a Formalization of pi-calculus Processes in Higher Order Abstract Syntax

Higher order abstract syntax is a natural way to formalize programming languages with binders, like the pi-calculus, because alpha-conversion and beta-reduction are delegated to the meta level of the provers, making tedious substitutions superfluous. However, such formalizations usually lack induction principles, and often give rise to exotic terms. Induction is necessary in syntax analysis, and certain important syntactic properties might be invalid in the presence of exotic terms. The paper introduces well formedness predicates for the pi-calculus with which exotic terms are excluded and, simultaneously, induction principles are obtained. The principles are then used in formal proofs of vital syntactic properties, mechanized in Isabelle/HOL.La syntaxe abstraite d'ordre supérieur est une technique pour la formalisation de langages comportant des constructions liantes tels que le pi-calcul. Grâce à cette technique, l'utilisateur n'a pas à gérer explicitement une notion de substitution, l'alpha-conversion et la béta-réduction faisant intervenir les variables du niveau meta; Cependant, dans une telle approche, l'on ne dispose pas de principe d'induction de manière naturelle, et de plus le langage tel qu'il est formalisé peut englober des termes considérés comme exotiques; Dans ce travail nous définissons des prédicats de bonne formation pour le pi-calcul permettant d’éliminer les termes exotiques et fournissant des principes d'induction? Ceci rend possible la preuve de propriétés syntaxiques essentielles pour le pi-calcul., que nous formalisons dans le système Isabelle/HO

An HFB scheme in natural orbitals

We present a formulation of the Hartree-Fock-Bogoliubov (HFB) equations which solves the problem directly in the basis of natural orbitals. This provides a very efficient scheme which is particularly suited for large scale calculations on coordinate-space grids.Comment: 5 pages RevTeX, (Postscript-file also available at http://www.th.physik.uni-frankfurt.de/~bender/nucl_struct_publications.html or at ftp://th.physik.uni-frankfurt.de/pub/bender ), accepted for publication in Z. Phys.

The rp-process and new measurements of beta-delayed proton decay of light Ag and Cd isotopes

Recent network calculations suggest that a high temperature rp-process could explain the abundances of light Mo and Ru isotopes, which have long challenged models of p-process nuclide production. Important ingredients to network calculations involving unstable nuclei near and at the proton drip line are $\beta$-halflives and decay modes, i.e., whether or not $\beta$-delayed proton decay takes place. Of particular importance to these network calculation are the proton-rich isotopes $^{96}$Ag, $^{98}$Ag, $^{96}$Cd and $^{98}$Cd. We report on recent measurements of $\beta$-delayed proton branching ratios for $^{96}$Ag, $^{98}$Ag, and $^{98}$Cd at the on-line mass separator at GSI.Comment: 4 pages, uses espcrc1.sty. Proceedings of the 4th International Symposium Nuclei in the Cosmos, June 1996, Notre Dame/IN, USA, Ed. M. Wiescher, to be published in Nucl.Phys.A. Also available at ftp://ftp.physics.ohio-state.edu/pub/nucex/nic96-gs

High-precision measurement of the half-life of 62^{62}Ga

The beta-decay half-life of 62Ga has been studied with high precision using on-line mass separated samples. The decay of 62Ga which is dominated by a 0+ to 0+ transition to the ground state of 62Zn yields a half-life of T_{1/2} = 116.19(4) ms. This result is more precise than any previous measurement by about a factor of four or more. The present value is in agreement with older literature values, but slightly disagrees with a recent measurement. We determine an error weighted average value of all experimental half-lives of 116.18(4) ms.Comment: 9 pages, 5 figures, accepted for publication in PR

Alpha-decay lifetimes semiempirical relationship including shell effects

A new version of the semiempirical formula based on fission approach of alpha decay is derived, by using the optimum values of the fitting parameters determined for even-even nuclei, combined with hindrance factors for even-odd, odd-even, and odd-odd nuclides. The deviations from experimental data for two regions of nuclear chart (493 alpha emitters with Z=52-118 and 142 transuranium nuclei including superheavies (Z=92-118), respectively) are compared with those obtained by using the universal curve and the Viola-Seaborg semiempirical relationship.Comment: 11 pages, 3 figures, revtex