Search for dissertations about: "upward lighting"

Found 2 swedish dissertations containing the words upward lighting.

2. 1. Measurements of X-Ray Emission from Laboratory Sparks and Upward Initiated Lightning

   Author : Pasan Hettiarachchi; Vernon Cooray; Mats Leijon; Mahbubur Rahman; Marcos Rubinstein; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; X-ray; upward lighting; laboratory discharges; energy distribution;

   Abstract : In 1925 Nobel laureate R. C. Wilson predicted that high electric fields of thunderstorms could accelerate electrons to relativistic energies which are capable of generating high energetic radiation. The first detection of X-rays from lightning was made in 2001 and from long sparks in 2005. READ MORE

4. 2. Understanding the interactions between vibrational modes and excited state relaxation in garnet structured phosphors

   Author : Yuan-Chih Lin; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; free electron laser; thermal quenching.; luminescence; garnet; vibrational spectroscopy; neutron scattering; phosphor; light emitting diode;

   Abstract : This thesis concerns investigations of the local structural environments and vibrational dynamics of the three garnet type oxide phosphors Ce3+-doped Y3Al5O12 (YAG:Ce3+), Ca3Sc2Si3O12 (CSS:Ce3+), and Sr3Y2Ge3O12 (SYG:Ce3+), which show promising optical properties as luminescent materials used in solid state white lighting technologies. The study focuses on a comprehensive analysis of the nature of the long-range vibrations (phonons) in terms of local atomic and molecular motions of the garnet structure, as well as their dependence on the nature of the garnet chemical composition, Ce3+ concentration and temperature. READ MORE