Decay of correlations in the dissipative two-state system

We study the equilibrium correlation function of the polaron-dressed tunnelling operator in the dissipative two-state system and compare the asymptoptic dynamics with that of the position correlations. For an Ohmic spectral density with the damping strength $K=1/2$, the correlation functions are obtained in analytic form for all times at any $T$ and any bias. For $K<1$, the asymptotic dynamics is found by using a diagrammatic approach within a Coulomb gas representation. At T=0, the tunnelling or coherence correlations drop as $t^{-2K}$, whereas the position correlations show universal decay $\propto t^{-2}$. The former decay law is a signature of unscreened attractive charge-charge interactions, while the latter is due to unscreened dipole-dipole interactions.Comment: 5 pages, 5 figures, to be published in Europhys. Let

Dissipate locally, couple globally: a sharp transition from decoupling to infinite range coupling in Josephson arrays with on-site dissipation

We study the T=0 normal to superconducting transition of Josephson arrays with {\it on-site} dissipation. A perturbative renormalization group solution is given. Like the previously studied case of {\it bond} dissipation (BD), this is a "floating" to coupled (FC) phase transition. {\it Unlike} the BD transition, at which {\it only} nearest-neighbor couplings become relevant, here {\it all} inter-grain couplings, out to {\it infinitely} large distances, do so simultaneously. We predict, for the first time in an FC transition, a diverging spatial correlation length. Our results show the robustness of floating phases in dissipative quantum systems.Comment: 7+ pages, 3 eps figures, Europhysics Letters preprint format, as publishe

The Pulsed Power Converter and Septum Magnet System for Injection into the Electron Storage Ring at ESRF

At ESRF, the European Synchrotron Radiation Facility in Grenoble, electrons are accelerated, via a 200 MeV Linac and a 6 GeV synchrotron booster, and injected into the storage ring at 10 Hz rate. Two thin septum blade magnets and an eddy current sheet type septum magnet provide the final deflection of the injected beam. The operational requirements of the e- injection scheme and the resulting demanding hardware specifications are recalled. The pulsed septum magnets are briefly described. The design, circuit layout and construction of the power converters are related with emphasis on innovative aspects of general interest. Results of tests during commissioning are reported

TRUNK POSTURE AND STATICO-DYNAMICAL SPINE ANALYSIS– COMPARING ULTRASOUND BASED VS. OPTICALLY BASED MEASUREMENT SYSTEM

The purpose of this study was to compare two different methods measuring trunk posture and statico-dynamical spine analysis. 32 patients participated in this cross sectional study. Comparing measured values a wide congruence could be demonstrated with marginal underestimating in kyphosis and lordosis data for the ultrasound based system. The largest deviation could be shown for pelvic obliquity measured in mm. Trunk inclination, vertical deflection and pelvic obliquity measured in degree showed proper analogy for both measuring systems. Validity, reliability based on particular technical principles could be verified

Magnetic Soret effect: Application of the ferrofluid dynamics theory

The ferrofluid dynamics theory is applied to thermodiffusive problems in magnetic fluids in the presence of magnetic fields. The analytical form for the magnetic part of the chemical potential and the most general expression of the mass flux are given. By employing these results to experiments, global Soret coefficients in agreement with measurements are determined. Also an estimate for a hitherto unknown transport coefficient is made.Comment: 7 pages, 2 figure

The fracture behavior of Cr2AlC coatings

The erosion - and self-healing - behavior of Cr2AlC MAX phase coatings has been investigated [1]. It is well known that Cr2AlC coatings can be deposited at temperatures of around 450 °C [2], which is significantly lower than for other MAX phase systems, which often require growth temperatures around 900 °C [3]. To further explore the applicability of the Cr2AlC system in harsh environments, it is necessary to determine its mechanical response. Recent advances in micromechanical testing allow investigating the mechanical properties of hard coatings, especially the fracture behavior, which is of particular interest for several thin film applications. Furthermore, it is possible to deposit the Cr2AlC system with different microstructures, e.g. nanocrystalline or amorphous [2]. Preliminary results revealed a fracture toughness of ~2 MPam1/2 for a coating with columnar morphology. In this investigation, the effect of morphology and microstructure on the fracture toughness of Cr2AlC coatings will be presented. References [1] D. Eichner, A. Schlieter, C. Leyens, L. Shang, S. Shayestehaminzadeh, J.M. Schneider, Solid particle erosion behavior of nanolaminated Cr2AlC films, Wear. 402–403 (2018) 187–195. doi:10.1016/j.wear.2018.02.014. [2] C. Walter, D.P. Sigumonrong, T. El-Raghy, J.M. Schneider, Towards large area deposition of Cr2AlC on steel, Thin Solid Films. 515 (2006) 389–393. doi:10.1016/j.tsf.2005.12.219. [3] P. Eklund, M. Beckers, U. Jansson, H. Högberg, L. Hultman, The Mn+1AXn phases: Materials science and thin-film processing, Thin Solid Films. 518 (2010) 1851–1878. doi:10.1016/j.tsf.2009.07.184

CHANGES IN ISOMETRIC AND ISOKINETIC STRENGTH, POSTURAL BALANCE AND ENDURANCE AFTER THAI-BO TRAINING PROGRAM

The objective of the present study was to examine the influence of a long term Thai-Bo training program on muscular strength of the knee muscles, postural balance, and cardiovascular parameters. Thirty-five volunteers participated in two groups. Pre-and posttest with measuring of isometric and isokinetic strength of knee extension/flexion as well as postural balance on a force plate were performed before and after a weekly six-months training period. Furthermore cardiovascular parameters were measured during a stepwise increasing cycle ergometry. The results showed a significant increase of isometric strength and isokinetic strength at 600 /s in addition to an improvement in postural balance. Also a significant improvement of cardiovascular parameters in retest could be demonstrated