Sökning: "3D Inversion"

Visar resultat 11 - 15 av 33 avhandlingar innehållade orden 3D Inversion.

1. 11. Inversion of Magnetotelluric Data Constrained by Borehole Logs and Reflection Seismic Sections

   Författare :Ping Yan; Thomas Kalscheuer; Laust Pedersen; Maria Garcia Juanatey; Andreas Junge; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetotellurics; constrained inversion; borehole logs; seismic; COSC; Alnö alkaline and carbonatite; airborne VLF; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

   Sammanfattning : This thesis presents two new algorithms for doing constrained Magnetotelluric (MT) inversion based on an existing Occam 2D inversion program. The first algorithm includes borehole resistivity logs as prior information to constrain resistivity directly in the vicinity of boreholes. LÄS MER

3. 12. MRI evaluation and image processing in gel dosimetry. A study of selected MRI properties and image processing in 3D gel dosimetry

   Författare :Peter Magnusson; Malmö Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Klinisk fysiologi; medical instrumentation; tomography; radiology; Clinical physics; image registering; multi-slice; slice profile; ferrous sulphate; polyacrylamide; 3D volume acquisition; RF field; B1 field; relaxation time; T1; T2; spin-echo; multi-spin-echo; stochastic noise; nonuniformity; SNR; radiologi; tomografi; medicinsk instrumentering; Radiopharmaceutical technology; Radiofarmaceutisk teknik; Physics; Fysik;

   Sammanfattning : Gel dosimetry is a new dosimetry method applied in radiation therapy. Gel dosimeters consist of a radiation sensitive gel, which can integrate absorbed doses from several radiation sources or beams. The dose to the gel can be evaluated by magnetic resonance imaging (MRI), a procedure that is the focus of the present thesis. LÄS MER

4. 13. The crustal architecture of the central Skellefte district, Sweden : Structural analysis, setting of VMS deposits and 3D-modelling

   Författare :Tobias E. Bauer; Allan Gibbs; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Malmgeologi; Ore Geology;

   Sammanfattning : The Skellefte district in northern Sweden is a Palaeoproterozoic volcanic arc hosting abundant volcanogenic massive sulphide (VMS) deposits. The dominating rocks in the district are submarine volcanic and volcaniclastic rocks of the Skellefte Group deposited in an extensional regime at 1.89–1.88 Ga. LÄS MER

5. 14. Direct Fourier methods in 3D-reconstruction from cone-beam data

   Författare :Caroline Axelsson; Michel Defrise; Linköpings universitet; []
   Nyckelord :;

   Sammanfattning : The problem of 3D-reconstruction is encountered in both medical and industrial applications of X-ray tomography. It would seem natural to recover volume data by just repeating 2D-reconstructions slice-by-slice. LÄS MER

7. 15. From 2D to 3D Models of Electrical Conductivity based upon Magnetotelluric Data : Experiences from two Case Studies

   Författare :Juliane Hübert; Laust B Pedersen; Ari Tryggavson; Toivo Korja; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Magnetotelluric measurements are among the few geophysical techniques capable of imaging the structure both in the shallow subsurface as well as the entire crust of the Earth. With recent technical and computational advances it has become possible to derive three-dimensional inversion models of the electrical conductivity from magnetotelluric data, thereby overcoming the problems arising from the simplified assumption of two-dimensionality in conventional two-dimensional modeling. LÄS MER