Sökning: "echo"

Visar resultat 26 - 30 av 191 avhandlingar innehållade ordet echo.

1. 26. Diffusion MRI: Aspects of Reproducibility and Novel Segmented 2D and 3D Approaches for Higher Resolution and Geometric Fidelity

   Författare :Jens Johansson; Göteborgs universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Diffusion-weighted imaging; 3D-DWI; Time-Dependent ADC; DWi; Diffusion Time; Multi-Shot DWI; Echo- Planar Imaging; Geometric Distortion;

   Sammanfattning : Diffusion-weighted imaging (DWI) is a very useful tool for non-invasive imaging and clinical investigation of the human body. It provides data of the water diffusion process. LÄS MER

3. 27. Charged colloids observed by electrophoretic and diffusion NMR

   Författare :Erik Thyboll Pettersson; Peter Stilbs; Terence Cosgrove; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Analytical chemistry; ENMR; electrophoretic NMR; dissusion NMR; electrophoretic mobility; double stimulated echo; Analytisk kemi; Analytical chemistry; Analytisk kemi;

   Sammanfattning : The thesis deals partly with methodology including construction of hardware and new pulse sequences in the field of electrophoretic NMR, and partly with practical use of ENMR and diffusion NMR in the investigation of charged colloidal systems. Several sources of artefacts are investigated, including gas production at the electrodes, electroosmosis and Joule heating effects that can cause convection. LÄS MER

4. 28. The role of young-of-the-year fish in lake ecosystems

   Författare :Pia Romare; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Hydrobiology; Rutilus rutilus; Perca fluviatilis; diet-dependent growth; density dependent growth; behavioural cascade; 0 fish behaviour; horizontal echo sounding; biomanipulation; trophic cascade; predation pressure; young-of-the-year fish; trophic interactions; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi;

   Sammanfattning : Food chain theory is based on consumption; that is, presupposing that the only important interaction between organisms is that they actually meet in an unstructured environment and that one of them is consumed. Recently, studies, including biomanipulation projects, have indicated that trophic interactions are more complex than predicted by food chain theory. LÄS MER

5. 29. Parameter and State Estimation with Information-rich Signals

   Författare :Magnus Evestedt; Alexander Medvedev; Fredrik Gustafsson; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; information-rich signals; audio; video; acoustic echo cancellation; steel production; LD-converter; Kalman filter; covariance windup; recursive parameter estimation; Automatic control; Reglerteknik;

   Sammanfattning : The complexity of industrial systems and the mathematical models to describe them increases. In many cases, point sensors are no longer sufficient to provide controllers and monitoring instruments with the information necessary for operation. The need for other types of information, such as audio and video, has grown. LÄS MER

7. 30. Molecular Dynamics Simulations of Fluid Lipid Membranes

   Författare :Erik G. Brandt; Olle Edholm; Mats Wallin; Markus Deserno; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; biological fluid dynamics; biomembranes; hydrodynamics; lipid bilayers; molecular dynamics; neutron spin echo;

   Sammanfattning : Lipid molecules form thin biological membranes that envelop all living cells, and behave as two-dimensional liquid sheets immersed in bulk water. The interactions of such biomembranes with their environment lay the foundation of a plethora of biological processes rooted in the mesoscopic domain - length scales of 1-1000 nm and time scales of 1-1000 ns. LÄS MER