Synchrotron X-ray study of orthorhombic Rb(3)Ta(5)O(14) with a modified pyrochlore structure.
The structure of a new orthorhombic trirubidium pentatantalum oxide (Rb(3)Ta(5)O(14)) phase with Pnma symmetry was identified from a half sphere of synchrotron X-ray data measured at a wavelength of 0.85 A. This notionally linked TaO(6) octahedral structure broadly consists of three different modifications of the pyrochlore ring motif with layer stacking normal to (205) planes. Successive pyrochlore layers do not simply stack normal to these planes but are offset along the [100] axis. An unusual aspect of this structure is the occurrence of TaO(5) trigonal bipyramids in structurally complex regions where the modified pyrochlore rings connect.
Synchrotron X-ray study of ortho­rhombic Rb3Ta5O14 with a modified pyrochlore structure
The structure of a new orthorhombic trirubidium pentatantalum oxide (Rb3Ta5O14) phase with Pnma symmetry was identified from a half sphere of synchrotron X-ray data measured at a wavelength of 0.85 A. This notionally linked TaO6 octahedral structure broadly consists of three different modifications of the pyrochlore ring motif with layer stacking normal to (205) planes. Successive pyrochlore layers do not simply stack normal to these planes but are offset along the [100] axis. An unusual aspect of this structure is the occurrence of TaO5 trigonal bipyramids in structurally complex regions where the modified pyrochlore rings connect.
Archaeological Survey of Dangoyama Kofun by 3DGPR
We presented a three-dimensional ground penetrating radar (3DGPR) system for the archeological investigation in a harsh site, where we have to deal with many trees and/or great topographic variations. This system consists of a commercial GPR system with a laser positioning system. With this system, we can move the GPR antenna freely, on which a positioning detector can record accurate position for each GPR data trace. We applied our 3DGPR system at Dangoyama Kofun, a burial mound, in Fukushima prefecture, Japan. A lot of trees and bushes covered the survey area and cannot be cut. We acquired six datasets in two days in this area. We successfully imaged the boundary between the original surface of the burial mound and the covering soil clearly at about 0.3 m depth around the mound. Furthermore, we found some strong reflections appeared at 0.8 m depth in the top area of the mound, which can be from the artificial parts of the burial mound. The results would greatly aid the following archaeological excavation. In addition, we compared the non-interpolated depth slice with interpolated depth slice at same position and demonstrated that the interpolation process on threedimensional GPR data may introduce some artifacts which might mislead our interpretation.