First-principles study of TMNan (TM= Cr, Mn, Fe, Co, Ni; n = 4-7) clusters

Geometry, electronic structure, and magnetic properties of TMNan (TM=Cr-Ni; n = 4-7) clusters are studied within a gradient corrected density functional theory (DFT) framework. Two complementary approaches, the first adapted to all-electron calculations on free clusters, and the second been on plane wave projector augmented wave (PAW) method within a supercell approach are used. Except for NiNan, the clusters in this series are found to retain the atomic moments of the TM atoms, and the magnetic moment presented an odd-even oscillation with respect to the number of Na atoms. The origin of these odd-even oscillations is explained from the nature of chemical bonding in these clusters. Differences and similarities between the chemical bonding and the magnetic properties of these clusters and the TMNan (TM = Sc, V and Ti; n = 4-6) clusters on one hand, and TM-doped Au and Ag clusters on the other hand, are discussed

Calibration of the Interferometric X-SAR System on SRTM

We present the interferometric calibration of the X-SAR system on SRTM. From the height sensitivity analysis we identify key system parameters influencing the height reconstruction performance. Possible error sources in the radar instrument and the geometry determination are discussed. We outline the methods for calibrating the electronics and the geometric parameters and present first results of simulations

Shuttle Radar Topography Mission (SRTM) Calibration of the X-SAR-System and Validation of the X-SAR Products

The heart of the SRTM is a SAR interferometer using the existing SIR-C/X-SAR hardware in the shuttle cargo bay augmented by secondary C- and X-band receive antennas mounted at the tip of a 60 m boom. The most critical part of X-SAR electronics are the boom cables, where we expect high temperature variations between -70 C and +50 C

Shuttle Radar Topography Mission: X-SAR Calibration and Validation Concept

The third SIR-C/X-SAR flight will be a mission dedicated to topographic mapping of the entire land mass between latitudes +60 C: the Shuttle Radar Topography Mission (SRTM)

A New Concept of Radiometric, Polarimetric and Interferometric SAR Calibration using Coded Transponders

SAR instruments require careful calibration to ensure the fidelity of the image data. The use of reference targets on the ground as calibration standards is a proven technique. However, for new generations of SAR instruments using new wavelengths with polarimetric and interferometric modes, new calibration techniques need to be considered. Transponders which code the signal received from the SAR before retransmission have the advantages of unambiguous detection and decoupling of the signal from the surrounding targets. The coded transponder technique and its use fro SAR calibration are discussed