1,208 research outputs found

    Journal Publishers Approaches to Self-Archiving and Open Access : ZIM Briefing Paper

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    Overview - Analysis of 80 scholarly publishers' copyright agreements - Selected examples from major publishers regarding self-archiving - Selected Reading and selected websites - Appendix A: Analysis of Copyright Transfer Agreements (CTA) and/or Licences of commercial Publishers and Learned Societies-Extract

    Smoothed Complexity Theory

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    Smoothed analysis is a new way of analyzing algorithms introduced by Spielman and Teng (J. ACM, 2004). Classical methods like worst-case or average-case analysis have accompanying complexity classes, like P and AvgP, respectively. While worst-case or average-case analysis give us a means to talk about the running time of a particular algorithm, complexity classes allows us to talk about the inherent difficulty of problems. Smoothed analysis is a hybrid of worst-case and average-case analysis and compensates some of their drawbacks. Despite its success for the analysis of single algorithms and problems, there is no embedding of smoothed analysis into computational complexity theory, which is necessary to classify problems according to their intrinsic difficulty. We propose a framework for smoothed complexity theory, define the relevant classes, and prove some first hardness results (of bounded halting and tiling) and tractability results (binary optimization problems, graph coloring, satisfiability). Furthermore, we discuss extensions and shortcomings of our model and relate it to semi-random models.Comment: to be presented at MFCS 201

    Recoil correction to the bound-electron g factor in H-like atoms to all orders in αZ\alpha Z

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    The nuclear recoil correction to the bound-electron g factor in H-like atoms is calculated to first order in m/Mm/M and to all orders in αZ\alpha Z. The calculation is performed in the range Z=1-100. A large contribution of terms of order (αZ)5(\alpha Z)^5 and higher is found. Even for hydrogen, the higher-order correction exceeds the (αZ)4(\alpha Z)^4 term, while for uranium it is above the leading (αZ)2(\alpha Z)^2 correction.Comment: 6 pages, 3 tables, 1 figur

    Toward high-precision values of the self energy of non-S states in hydrogen and hydrogen-like ions

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    The method and status of a study to provide numerical, high-precision values of the self-energy level shift in hydrogen and hydrogen-like ions is described. Graphs of the self energy in hydrogen-like ions with nuclear charge number between 20 and 110 are given for a large number of states. The self-energy is the largest contribution of Quantum Electrodynamics (QED) to the energy levels of these atomic systems. These results greatly expand the number of levels for which the self energy is known with a controlled and high precision. Applications include the adjustment of the Rydberg constant and atomic calculations that take into account QED effects.Comment: Minor changes since previous versio

    Finite nuclear size and Lamb shift of p-wave atomic states

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    We consider corrections to the Lamb shift of p-wave atomic states due to the finite nuclear size (FNS). In other words, these are radiative corrections to the atomic isotop shift related to FNS. It is shown that the structure of the corrections is qualitatively different from that for s-wave states. The perturbation theory expansion for the relative correction for a p1/2p_{1/2}-state starts from αln(1/Zα)\alpha\ln(1/Z\alpha)-term, while for s1/2s_{1/2}-states it starts from Zα2Z\alpha^2 term. Here α\alpha is the fine structure constant and ZZ is the nuclear charge. In the present work we calculate the α\alpha-terms for 2p2p-states, the result for 2p1/22p_{1/2}-state reads (8α/9π)[ln(1/(Zα)2)+0.710](8\alpha/9\pi)[\ln(1/(Z\alpha)^2)+0.710]. Even more interesting are p3/2p_{3/2}-states. In this case the ``correction'' is by several orders of magnitude larger than the ``leading'' FNS shift.Comment: 4 pages, 2 figure

    Технико-экономические и экологические аспекты утилизация шламов, содержащих соединения цинка

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    По причине токсичности перед сбросом в водоемы ионы цинка выделяются из сточных вод в виде твердых соединений, которые осаждаются в виде шлама в прудах-накопителях. Приведены данные по количественному и качественному составам шлама в накопителеотстойнике предприятия по производству вискозного волокна. Отмечено, что такой накопитель в г. Красноярске является техногенным образованием содержащем ценное сырье - цинк. Поэтому необходима разработка и внедрение технологий переработки и утилизации цинксодержащих шламов различных производств.Zinc ions are toxic and they are isolated from sewage in the form of solid compounds before discharge into water bodies. Precipitation occurs in the form of slime in storage ponds. Data on the quantitative and qualitative composition of the sludge in the reservoir-settler of an enterprise for the production of viscose fiber are given. It is noted that such a storage facility in Krasnoyarsk is a technogenic for mation containing valuable raw materials - zinc. Therefore, it is necessary to develop and implement technologies for processing and utilization of zinc-containing slurries of various industries

    HITRAP: A facility at GSI for highly charged ions

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    An overview and status report of the new trapping facility for highly charged ions at the Gesellschaft fuer Schwerionenforschung is presented. The construction of this facility started in 2005 and is expected to be completed in 2008. Once operational, highly charged ions will be loaded from the experimental storage ring ESR into the HITRAP facility, where they are decelerated and cooled. The kinetic energy of the initially fast ions is reduced by more than fourteen orders of magnitude and their thermal energy is cooled to cryogenic temperatures. The cold ions are then delivered to a broad range of atomic physics experiments.Comment: 8 pages, 11 figure
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