Sökning: "current measurement"

Visar resultat 16 - 20 av 514 avhandlingar innehållade orden current measurement.

1. 16. A bird's eye-view of smallholder productivity : Current measurement shortfalls, farmer perceptions and rationality on rainfed family farms in Ghana

   Författare :Ibrahim Wahab; Institutionen för kulturgeografi och ekonomisk geografi; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; Smallholder productivity; measurement shortfalls; maize yield levels; aerial photos; farmer attitudes; Ghana;

   Sammanfattning : Smallholder farming, which is largely rainfed and relies on mostly rudimentary tools, predominates Ghana’s agricultural sector. The sector’s importance to the national economy is exemplified in not only the proportion of the active national labour force engaged in it but also in terms of its export earnings and service as a source of food for the vast majority of the population. LÄS MER

3. 17. Projective methods and longitudinal developmental research : considerations of data's nature and reliability

   Författare :Harald Janson; Bertil Mårdberg; Stockholms universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Longitudinal studies; projective methods; reliability; temporal stability; interrater agreement; epistemology; measurement; psykologi; Psychology;

   Sammanfattning : A projective method is viewed in the present work as a psychological test, by which is understood a standardized task that is set before a person, the solution of which is used for making inferences about psychological quantities. The present research was designed to shed light on several aspects of the usefulness of projective methods in longitudinal research, particularly with regard to reliability and to the distinction between measurement and theory-free empirical-comparison data. LÄS MER

4. 18. Processing and characterization of GaN/SiC heterojunctions and SiC bipolar transistors

   Författare :Erik Danielsson; KTH; []
   Nyckelord :silicon carbide; gallium nitride; device simulation; bipolar junction transistor; heterojunction; heterojunction bipolar transistor; current-voltage measurement; capacitance-voltage measurement; self-heating;

   Sammanfattning : Silicon Carbide (SiC) and Gallium Nitride (GaN) are bothwide bandgap semiconductors that have been suggested for highpower, high voltage, and high temperature applications. Themost investigated SiC devices so far are the Schottky diode,PiN diode and the field effect transistor. LÄS MER

5. 19. EMC barriers : measurement methodologies and model verification

   Författare :Urban Lundgren; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Industrial Electronics; Industriell elektronik;

   Sammanfattning : The subject of Electromagnetic Compatibility (EMC) is introduced. A short overview of the regulatory EMC requirements in Europe and in the United States is presented. An explanation is given why it is important for people in the electronics business to understand the need for EMC regulations. LÄS MER

7. 20. Nonlinear Characterisation and Modelling of Microwave Semiconductor Devices

   Författare :Mattias Thorsell; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; noise modelling; nonlinear measurement; active load-pull; noise measurement; thermal characterisation; AlGaN GaN HEMT; nonlinear modelling;

   Sammanfattning : There is an increasing need for more accurate models taking into account the nonlinearities and memory effects of microwave transistors. The memory effects are especially important for transistor technologies suffering from relatively large low frequency dispersion, such as GaN baed HEMTs. LÄS MER