Sökning: "transient processes"

Visar resultat 6 - 10 av 265 avhandlingar innehållade orden transient processes.

1. 6. Simplified models for emission formation in diesel engines during transient operation

   Författare :Anders Westlund; Hans-Erik Ångström; Martti Larmi; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Diesel engine; emission modeling; transient operation; NOx; Soot; Mechanical energy engineering; Mekanisk energiteknik;

   Sammanfattning : The work presented in this thesis is the result of the KTH CICERO project “Dynamic Engine Performance” in which the main objective was to develop simple models foremission formation. The demand for such models is increasing, mainly due to the tightening emission legislation for diesel engines which has lead to more complex engines and thereby more laborious development and calibration processes. LÄS MER

3. 7. Cross-functional brain imaging of attention, memory, and executive functions : Unity and diversity of neurocognitive component processes

   Författare :Petter Marklund; Lars Nyberg; Akira Miyake; Umeå universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Human memory; executive functions; prefrontal cortex; sustained and transient neural activity; declarative long-term memory; attention; working memory; functional neuroimaging; cognitive control.; Psychology; Psykologi;

   Sammanfattning : The central theme of the present thesis revolves around the exploration of similarities and differences in brain activity patterns invoked by the component processes underlying mnemonic, executive and attentional functions. The primary aim was to identify and functionally characterize commonly recruited brain regions in terms of shared component processes, which has been a largely neglected area of research in cognitive neuroscience. LÄS MER

4. 8. Estimation and Classification of Non-Stationary Processes : Applications in Time-Frequency Analysis

   Författare :Johan Brynolfsson; Statistical Signal Processing Group; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Time-Frequency Estimation; Parameter Estimation; Reassignment method; Non-Stationary Processes; Smooth spectral estimation; Neural Networks;

   Sammanfattning : This thesis deals with estimation and classification problems of non-stationary processes in a few special cases.In paper A and paper D we make strong assumptions about the observed signal, where a specific model is assumed and the parameters of the model are estimated. LÄS MER

5. 9. Excited State Processes in Solar Energy Materials

   Författare :Tomas Österman; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solar cells; Conjugated polymers; Charge transfer state; Time-resolved spectroscopy; Fluorescence; Artificial Photosynthesis; Bis-tridentate ruthenium II -complexes; Density functional theory; Quantum chemistry.;

   Sammanfattning : This dissertation covers studies of excited state processes in two types of solar energy materials: alternating polyfluorene polymers and their blends with fullerenes in the active layer of plastic solar cells, and bis-tridentate RuII-polypyridyl complexes to be used as sensitizer in systems for artificial photosynthesis. The polymer:fullerene blends were studied by transient absorption and time-resolved fluorescence measurements in order to investigate the role of the charge transfer (CT) state in charge formation. LÄS MER

7. 10. Stimulated scattering processes and cross-phase modulation effects in optical fibres

   Författare :Anders Höök; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; phase-shift keying; walk-off; optical fibres; cross-phase modulation; transient stimulated Brillouin scattering; stimulated Raman scattering;

   Sammanfattning : .... LÄS MER