Modern Determination of Vertical Deflections Using Digital Zenith Cameras

At the beginning of the 21st century, a significant technological change took place in geodetic astronomy. In Zurich and Hannover, digital zenith camera systems were developed based on digital imaging sensors (charge-coupled device) that strongly improved the degree of automation, efficiency, and accuracy of the observation of the direction of the plumb line and its vertical deflection. This paper describes the instrumental design of the new digital zenith camera systems and gives an overview of the data processing with focus on the models used for astrometric data reduction and tilt correction. Results of frequently repeated observations of vertical deflections and comparison measurements show an accuracy of vertical deflection measurements of better than 0.1 arc sec. Application examples for vertical deflection data from zenith camera observations, such as the high-precision local gravity field determination in engineering projects and gravity field validation are summarized

Vacancy Clusters at Nanoparticle Surfaces

The authors detect vacancy clusters at Au nanoparticle surfaces using a combination of positron lifetime spectroscopy, 1- detector, and 2-detector measurements of Doppler broadening of annihilation radiation. Gold nanoparticles are formed by MeV implantation of gold ions into MgO (100) followed by annealing. Clusters of two Mg and two O vacancies (v{sub 4}) are attached to the gold nanoparticle surfaces within the projected range (R{sub p})

Ein Modell zur numerischen Simulation der Temperatur eines Wohnhauses im meteorologischen Umfeld zur Untersuchung von Heizenergieeinsparungsmoeglichkeiten

TIB Hannover: ZA 5031 (42) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Data analysis of a dense GPS network operated during the ESCOMPTE campaign: first results.

International audienc

GPS water vapor project associated to the ESCOMPTE programme: description and first results of the field experiment

International audienc

GPS water vapor project associated to the ESCOMPTE programme: description and first results of the field experiment

International audienc

GPS water vapor project associated to the ESCOMPTE programme: description and first results of the field experiment

International audienc