Sökning: "characteristic temperature"

Visar resultat 1 - 5 av 179 avhandlingar innehållade orden characteristic temperature.

1. 1. Threshold and Temperature Characteristics of InGa(N)As-GaAs Multiple Quantum Well Lasers

   Författare :Göran Adolfsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; GaAs; Semiconductor lasers; molecular beam epitaxy; multiple quantum wells; characteristic temperature; temperature dependence; dilute nitrides; ambipolar diffusion; InGa N As;

   Sammanfattning : Semiconductor lasers emitting in the 1.3 μm regime are of interest for applications in access-networks like fiber-to-the-home and radio-over-fiber systems. Suchfiber optical networks are expected to replace the copper-based access-networks currently in use due to a continuously increasing demand on user bandwidth. LÄS MER

3. 2. Dilute Nitride Lasers and Spectrally Engineered Semiconductor Laser Resonators

   Författare :Göran Adolfsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; single mode laser; transfer matrix method; threshold current; InGaAs; GaAs; multiple quantum wells; dilute nitrides; two-color laser; GaInNAs; Semiconductor lasers; molecular beam epitaxy; characteristic temperature; temperature dependence; ambipolar diusion; Fabry-Perot resonator; spectral engineering;

   Sammanfattning : The first part of this thesis deals with long wavelength (1.2-1.3 um) InGaAs(N)multiple quantum-well (QW) lasers grown on GaAs, with the aim of understandingand improving their threshold and temperature characteristics. The epitaxialmaterial is grown by molecular beam epitaxy (MBE). LÄS MER

4. 3. Toughness of Tool Steel

   Författare :Henrik Jesperson; Håkan Engqvist; Birger Karlsson; Uppsala universitet; []
   Nyckelord :Toughness; Tool Steel; Heat Treatment; Temperature; Energy absorption; Impact Testing; Fracture Toughness Testing; Non-metallic Inclusions; Carbides; Nitrides; Statistics; TECHNOLOGY; TEKNIKVETENSKAP; Teknisk fysik med inriktning mot materialvetenskap; Engineering Science with specialization in Materials Science;

   Sammanfattning : Toughness is the ability to resist tensile stresses in the presence of a notch or crack. Sometimes gross cracking of industrial tools, mould or dies, occurs due to insufficient toughness. As the economic consequences of the gross cracking are serious, the toughness of industrial tool material, generally tool steel, is of paramount importance. LÄS MER

5. 4. Partial Discharge Signatures of Defects in Insulation Systems Consisting of Oil and Oil-impregnated Paper

   Författare :Mohamad Ghaffarian Niasar; Hans Edin; Peter Werelius; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partial discharge; transformer; oil; ageing; temperature; PD classification;

   Sammanfattning : Partial discharge measurement is a common method for monitoring and diagnostics of power transformers, and can detect insulation malfunctions before they lead to failure. Different parameters extracted from the measured PD activity can be correlated to the PD source, and as a result it is possible to identify the PD source by analyzing the PD activity. LÄS MER

7. 5. On the Properties of Some Strongly Correlated Systems - Analytical and Numerical Studies

   Författare :Jurij Smakov; KTH; []
   Nyckelord :mean field theory; magnetic multilayers; Curie temperature; compensation temperature; scanning tunneling microscopy; tunneling; superconductivity; local density of states; Josephson effect; tunneling Hamiltonian formalism; impurities in superconducto;

   Sammanfattning : This thesis is dedicated to analytical and numerical studiesof a few models of strongly correlated systems and thedevelopment of techniques for such studies. The common name"strongly correlated" refers to systems in which theinteractions (correlations) between the constituent particleslead to nontrivial properties, such as various types ofmagnetism, superconductivity, and exotic phases. LÄS MER