Quantum well solar cells with p-i-n structure are presented. The physical processes in multiple quantum well solar cells, the materials commonly used for photovoltaic applications, and technological aspects are analyzed. The quantum confinement effect produces resonant energy levels located in the valence and conduction bands of well layers. In addition, it produces energy quantum confinement l...

We present VLT-UVES echelle spectra of the Lyα emission and absorption in five radio galaxies at redshifts z=2.55–4.1. Together with data from our pilot study, we have a sample of 7 such systems with radio source sizes ∼ 1 − 90 kpc with which to address the origin of the absorbing gas. Echelle resolution again reveals that some systems with NHI > 10 cm in lower resolution data in fact consist o...

The use of solar collectors with coloured absorbers for water heating is an area of particular interest when considering their integration with buildings. By matching the absorber colour with that of the roof or façade of the building, it is possible to achieve an architecturally and visually pleasing result. Despite the potential for the use of coloured absorbers very little work has been unde...

We have carried out a high angular resolution near-infrared imaging study of the fields of 6 quasars with 7 strong absorption line systems at z < 0.5, using the Hokupa’a adaptive optics system and the QUIRC near-infrared camera on the Gemini-North telescope. These absorption systems include 4 classical damped Lyman-alpha absorbers (DLAs), 2 sub-DLAs, and one Lyman-limit system. Images were obta...

The state-of-the-art solar power system technologies are presented. Various methods of capturing solar energy using solar collectors such as parabolic trough collectors and dish collectors are reviewed. Combined heat and power (CHP) systems driven by concentrating solar absorbers and supplemented by biomass boilers are proving to be the most promising methods of domestic power generation. μCHP ...

This paper presents a numerical model for the calculation of the transmission loss of a panel with an array of tuned vibration absorbers attached. The transmission loss of the panel is calculated for the case of the bare panel, with tuned vibration absorbers attached, and equivalent blocking masses. The theoretical predictions of transmission loss are compared with experimental measurements.

Observations of warm absorbers provided new ways to study the nuclear environments of AGNs. I discuss basic properties of warm absorbers and early developments with ROSAT, ASCA and HST observations. I briefly touch upon recent advances made with Chandra and FUSE. Key-words : quasars: absorption lines– ultraviolet: galaxies– X-rays: galaxies

We have compiled a new and extensive catalog of heavy-element QSO absorption line systems and analyzed the distribution of absorbers in bright and faint QSOs, to search for gravitational lensing of background QSOs by the matter associated with the absorbers. There is a highly significant excess of C iv absorbers in bright QSOs in the redshift range z = 1.2 − 3.2, and this excess increases stron...

We report on a survey for narrow (FWHM < 600 km s) C iv absorption lines in a sample of bright quasars at redshifts 1.8 6 z < 2.25 in the Sloan Digital Sky Survey. Our main goal is to understand the relationship of narrow C iv absorbers to quasar outflows and, more generally, to quasar environments. We determine velocity zeropoints using the broad Mg ii emission line, and then measure the absor...