Ergebnisse direkter Messungen von Schubspannung und vertikalem Wärmetransport in der Atmosphäre dicht über dem Meer

Fluctuations of horizontal and vertical wind speed components and of air temperature have been measured on a mast in the Baltic Sea. Preliminary results of computed stress and sensible heat flux and their parametrisation with wind speed and air-sea temperature difference are given. Compared with the results of other authors, the present data show the following features: 1. The drag coefficient increases strongly with increasing wind speed. 2. The heat transfer coefficient seems to be smaller under stable stratification than under neutral or unstable conditions

Spin- and charge-density oscillations in spin chains and quantum wires

We analyze the spin- and charge-density oscillations near impurities in spin chains and quantum wires. These so-called Friedel oscillations give detailed information about the impurity and also about the interactions in the system. The temperature dependence of these oscillations explicitly shows the renormalization of backscattering and conductivity, which we analyze for a number of different impurity models. We are also able to analyze screening effects in one dimension. The relation to the Kondo effect and experimental consequences are discussed.Comment: Final published version. 15 pages in revtex format including 22 epsf-embedded figures. The latest version in PDF format is available from http://fy.chalmers.se/~eggert/papers/density-osc.pd