Emissions of methane were measured by a static chamber technique at 9 sites on 5 wetlands in the Eastern Temperate Wetland Region, north of Montreal. Mean daily methane fluxes measured from May to October ranged from 0.18 to 1071 mg/m$ sp2$/d, and estimated annual flux ranged from 0.02 to 186 g/m$ sp2$/y. Laboratory incubations of peat samples showed potential anaerobic methane production rates which ranged from 0.00 to 9.12 $ mu$g/g/d, and potential aerobic consumption rates from 0.55 to 3.75 $ mu$g/g/d. Seasonal methane emission patterns are related to water table level and CH$ sb4$ production and consumption potentials in the peat profile. Episodic fluxes were found to be important at several sites, contributing a significant portion of the total emissions. / Analysis of spectral reflectance data from 20 sites on 2 subarctic fens was carried out to address the issue of scaling up CH$ sb4$ emissions using satellite imagery. Hummocks, lawns and pools were found to be spectrally distinct enough to be differentiated by band 5 of Landsat MSS and band 3 of Landsat TM sensors. The averaging of spectral information in mixed pixels proved unlikely to be able to distinguish between wet lawn and string and pool communities. Such weaknesses can be overcome with the use of higher resolution data.

Silicon based hydrogenated amorphous semiconducting (intrinsic and n/p doped a-Si:H and a-Si1-xCx:H) thin films have been deposited by plasma enhanced chemical vapor deposition (PECVD) system. In order to analyze the optical response of these amorphous films, intrinsic optical absorption mechanisms have resumed and spectral variations of absorption coefficient &amp / #61537 / (E) are derived. The exponential variation of absorption coefficient for energies below the band edge is discussed in the frame of randomly distributed square well like potential fluctuations of localized states. Urbach constant EU and the slope B are deduced as disorder parameters. Both intensity sensitive transmittance and reflectance, and amplitude/phase sensitive ellipsometric techniques for multilayer thin films are theoretically and practically treated. Various methodologies are developed for the determination of thickness, refractive index and absorption coefficient of the films. A reflectance unit is adapted to the spectrometer and all the measuring instruments are computerized and relevant software packets have been developed. IR spectroscopy has been used for determination of mainly hydrogen concentrations and bonding properties. Establishing the production-characterization-improved growth conditions cycle successfully, the following results are obtained: (a) determination of lateral inhomogeneity of films along the radial direction of the plasma reactor, (b) determination of vertical inhomogeneity due to both substrate and air ambient, (c) perfect adjustment of refractive index and band gap of a-Si1-xCx:H films by changing carbon content of the films, (d) effect of plasma power density on both growth and carbon content.

Our aim was to establish a methodology for laser assisted oxidation of semiconductor and metal surfaces. One advantage of laser oxidation is the fact that radiation is heavily absorbed in a thin surface layer of the sample and the other is its ability for local oxidation. In addition to this, laser beam can be directed into some areas that other processes cannot reach. For these reasons, Nd:YAG pulsed laser working at 1064 nm wavelength is used for the oxidation purposes of Si and Ta films. First, SiO2 layer was obtained for various O2 pressures and laser powers. The thickness, refractive index, structural, dielectric, electrical and optical characteristics of the SiO2 layers have been determined. We have established that there exists an interval of laser power in which the oxidation occurs without surface melting. The oxidation process is controlled by the laser power rather than by the substrate temperature (673 &ndash / 748 K). It was found that better film quality is obtained at higher substrate temperatures and laser power greater than 3.36 J/cm2. Second, rf-sputtered Ta films were oxidized by laser, because Ta2O5 appears to be a good promising candidate to replace SiO2 because of its high dielectric constant, high breakdown voltage and relevant small leakage current values. It was found that the substrate temperature is an important parameter to obtain denser layers with reduced amount of suboxides and the most suitable substrate temperature range is around 350 C to 400 C. &amp / #946 / -orthorhombic crystal structure was obtained when the substrate temperature is 350 &ndash / 400 C for thinner films (up to 20 &ndash / 25 nm) and 300 &ndash / 350 C for thicker films (40 nm). The refractive index values of laser grown thin tantalum oxide films were between ~1.9 and 2.2 being close to those of bulk Ta2O5 (2.0 &ndash / 2.2). Oxide thicknesses in uniform Gaussian&ndash / like shapes were measured as around the twice of those initial Ta films. Effective dielectric constant values reached ~26 when the substrate temperature was increased from 250 C to around 400 C. It was shown that the leakage current density level decreases with increasing substrate temperature. However, the refractive index values of the films were smaller than those of thermally grown films. Porous structure formed during laser oxidation might be the reason for lower refractive indices and can be improved by post&ndash / oxidation annealing.

Polytetrafluoroethylene (PTFE) is a highly scattering material and has been used as diffuse reflectors. In the present study, the ranges of the scattering coefficient, absorption coefficient, and the asymmetric parameter of the Henyey-Greenstein scattering phase function are assessed for semitransparent PTFE films whose thicknesses range from 0.11 mm to 10 mm. The bidirectional reflectance distribution function (BRDF) and bidirectional transmittance distribution function (BTDF) of these PTFE films were measured using a laser scatterometer at a wavelength of 635 nm, and the directional-hemispherical reflectance and transmittance were obtained by integrating BRDF and BTDF at normal incidence. The scattering coefficient of PTFE is estimated to exceed 1200 (1/cm). On the other hand, the absorption coefficient should be less than 0.01 (1/cm). A Monte Carlo simulation was employed to predict the BRDF and BTDF of PTFE films, and the calculations were compared with measurements at various incidence angles.

Thesis (Ph.D.)--McMaster University (Canada), 1995. / Source: Dissertation Abstracts International, Volume: 57-03, Section: B, page: 1867. Adviser: T. Timusk.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Thesis (M.S.)--Rochester Institute of Technology, 1989. / Spine Title: Optically transparent heat mirror films. Includes bibliographical references (leaves 58-59).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed June 17, 2008). PDF text: xiii, 152 p. : ill. (some col.) ; 2 Mb. UMI publication number: AAT 3293917. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thèse (D.R.Min.) -- Université du Québec à Chicoutimi, 2001. / Bibliogr.: f. 237-249. Document électronique également accessible en format PDF. CaQCU

Thesis (M.S.)--Michigan State University. Packaging, 2008. / Title from PDF t.p. (viewed on Sept. 8, 2009) Includes bibliographical references (p. 132-144). Also issued in print.