Transport properties and the large anisotropic magnetoresistance of CuxNbS2 single crystals
The transport properties of CuxNbS2 (x = 0.09, 0.44 and 0.55) single crystals were systematically studied. The in-plane and out-of-plane resistivities decrease with increasing Cu content, and a transition with hysteresis shows up for the crystals with x = 0.44 and 0.55. The thermopower and Hall coefficient of CuxNbS2 show opposite signs, indicating that there are two kinds of carriers in this system. The angular dependences of the in-plane magnetoresistance (MRab = (ρab(H)−ρab(0))/ρab(0) × 100%) at different temperatures were also studied. The single crystals with x = 0.44 and 0.55 show a strong anisotropic MRab. For the x = 0.55 sample, MRab reaches 80% with a magnetic field of 14 T applied along the c-axis, while MRab is less than 5% for the magnetic field applied within the ab-plane. These results can be well understood in the light of the anisotropic Fermi surface in the multiband system.
Electron Diffraction Investigation of the AgxTaS2 System II. Superlattices, Structure, and Charge Density Waves in AgxTaS2
Superlattices are observed by electron diffraction in AgxTaS2 intercalation compounds having 0 < x ⪅ 2/3, in the temperature range from 400 to 25 K and are mainly explained as ordered silver superstructures. However, for x ⪅ 1/4 incommensurate side-band satellites, corresponding to a “3a0” incommensurate charge density wave (CDW/PLD), are also observed. For x ⪅ 1/4 the silver ions only order on a superlattice and it is argued that this is a consequence of the silver ions occupying, in a stage two fashion, octahedral sites between unshifted 2H-TaS2 host layers. As x = 1/3 is approached, the and the 2a0 superlattice satellites described in Part I of this paper coexist. For larger concentrations, in addition to weak superlattice satellites, essentially those described for x = 1/3 and 2/3 in Part I are found. 
 
 
 
Uberstrukturen werden mit Hilfe der Elektronenbeugung in AgxTaS2-Einlagerungsverbindungen, mit 0 < x ⪅ 2/3, im Temperaturbereich von 400 bis 25 K beobachtet und sind zum grosten Teil als Uberstrukturen der Silberionen erklarbar. Wenn jedoch x ⪅ 1/4 ist, sind periodische inkommensurable Uberstruktursatelliten zu sehen, welche mit einer „3a0”-Gitterverzerrung ubereinstimmen und von elektronischen Instabilitaten (CDW/PLD) verursacht werden. Fur x ⪅ 1/4 ordnen sich die Silberionen nur auf einem Supergitter und dies wird erklart als Folge der Einnahme von oktaherischen Platzen zwischen den gegenseitig noch unverschobenen 2H-TaS2 Schichten durch die Silberionen in einem Prozes zweiter Stufe. Wenn x sich an 1/3 annahert, sind die - und die 2a0-Uberstruktursatelliten, erklart im ersten Teil dieser Arbeit, zugleich vorhanden. Fur grosere Konzentrationen werden auser den schwachen -Uberstruktursatelliten auch die gefunden, welche fur x = 1/3 und 2/3 im Teil I beschrieben wurden.
Frequency distributions of the mixing height over an urban area from SODAR data
The height of the mixing-layer (MLH) is an important parameter in the assessment of the dilution of primarily emitted or secondarily formed air pollutants in the atmospheric boundary-layer. A continuous measurement of MLH is possible only by remote sensing. Here, 17 months of SODAR data have been analysed automatically to derive the MLH over the city of Hannover in Northern Germany. In contrast to earlier studies the MLH has been determined from vertical profiles of the acoustic backscatter intensity and from the variance of the vertical velocity component. The results are presented in form of monthly frequency distributions and mean daily courses of MLH. These statistical evaluations of MLH show a clear annual course and interannual variability. The study shows the possibility to derive meaningful climatological information from long-term SODAR measurements for air quality issues.