For improving the energy conversion efficiency of solar cells, it is essential to reduce the surface recombination velocity of CuInSe2 absorber layer. The use of quaternary alloys with an increasing band gap gradient was also demonstrated to be effectively increased the open-circuit voltage of the cells. The experiments using different concentration ammonium sulfur solutions to proceed surface passivation and sulfurization of CuInSe2 and CuInSe2¡GSb films have been conducted to evaluate their influences on the band gap and other related properties. The band gaps of Cu-rich and In-rich CuInSe2 films did not change after ammonium sulfur treatment. For CuInSe2¡GSb films after immersing (NH4)2Sx solution, the PL spectra gave an evidence of the formation of the quaternary CuInSxSe2-x alloys. The metal contacts to CuInSe2 films with the structures of Mo/P-type CuInSe2/Al and Mo/N-type CuInSe2/Au had been fabricated. Their I-V characteristics indicate that the Schottky Contacts had been successfully formed.

ABSTRACT Electrostatic discharge (ESD) influences a lot in the industries of petrochemistry, semiconductor, and electronics. ESD is one of the reasons for the deterioration of the lubricant in the lubrication system. In this study, to understand the performance of the frictional electrification of the lubricant, the reciprocating frictional electrification tester with the measurement systems is employed to investigate the friction electrification under the dry and lubricated conditions. The materials of the specimens are made of Fe and PTFE, and the paraffin base oil is used as the lubricant. Furthermore, the effects of the load, the sliding speed, and the duration of the friction on the friction electrification are investigated. Results show that the electrification voltage in the lubricated condition is much higher than that in the dry condition for the all-material pairs, but the surface voltage is reverse. The measured voltage is lower for the pair of Fe/PTFE and PTFE/Fe because the capacitance effect of the isolator disappears. When two conductors become a capacitor by inserting an insulator, such as Fe/PTFE-Fe, the frictional voltage is about 2~3 times higher than the other pairs because of the isolator capacitance. Moreover, the rotational speed, the normal load, and the duration also affect the output voltage. Among them, the rotational speed is the most significant parameter. At a certain normal load, the oil and the iron have different polarities, and their voltages increase with increasing rotational speed for Fe/Fe pair. In the polarity study; the tribo-electrification mechanism is proposed for Fe/PTFE, PTFE/Fe and Fe/PTFE-Fe pairs. The output voltages are negative at the lower and the upper specimens for Fe/PTFE and PTFE/Fe pairs, but negative and positive for Fe/PTFE-Fe pairs, respectively. After the surfaces of Fe and PTFE slide together, since the high residual negative voltage appears on PTFE, which causes the separation of induced charge on Fe, the surface residual voltage of PTFE dominates the polarity of output voltage. At Fe/PTFE-Fe pair, the polarity at the upper specimen of Fe is negative. However, the polarity at the lower specimen of Fe is positive, because the lower specimen is also influenced by the surface residual voltage of PTFE.

A geophysical survey presents many challenges. A scientist must be able to not only understand the theory and nature of the geophysics being applied but must also be able to identify features of interest in a dataset. It is also of extreme importance to be able to determine where, in the subsurface, the features identified in the data occur. This research is designed in an attempt to identify the locations of subsurface heterogeneities that affect geophysical instrument response. An experiment was conducted in which topography, magnetics, ground-penetrating radar (GPR), and electromagnetic induction (EM) data were collected over a defined survey line. An excavator with a modified flat-bladed bucket was used to remove, or skim, a 5 to 10 cm thick layer of material from the survey line. Upon removal of the material, datasets from the above mentioned instruments were again collected along the same survey line. This process was repeated for 10 skims, resulting in a total of 11 sets of data for each instrument. Having collected data with various instruments in the same location as material was progressively removed allowed for an empirical study with the goal of noting how the response of each instrument changed with respect to the removal of material. By observing how the anomalies changed in the data from one skim to the next, a better understanding of the location of the causative heterogeneities could be had. Data for each instrument was compared to the equivalent data collected from each subsequent skim to determine how similar or different the data appeared as the depth of the trench increased. The experiment also sought to determine if the topographic variations, or roughness, along the survey line had any impact of the geophysical signals. The data collected from each instrument were compared to the topographic roughness of the survey line for the corresponding skim.

The effect of the surface roughness of ice crystals is not routinely accounted for in current cloud retrieval algorithms that are based on pre-computed lookup libraries. In this study, we investigate the effect of ice crystal surface roughness on the retrieval of ice cloud effective particle size, optical thickness and cloud-top temperature. Three particle surface conditions, smooth, moderately rough and deeply rough, are considered in the visible and near-infrared channels (0.65 and 3.75 µm). The discrete ordinates radiative transfer (DISORT) model is used to compute the radiances for a set of optical thicknesses, particle effective sizes, viewing and illumination angles, and cloud temperatures. A parameterization of cloud bi-directional reflectances and effective emittances is then developed from a variety of particle surface conditions. This parameterization is applied in a 3-channel retrieval method for Moderate Resolution Imaging Spectroradiometer (MODIS) data at 0.65, 3.75, and 10.8 µm. Cloud optical properties are derived iteratively for each pixel that contains ice clouds. The impact of ice crystal surface roughness on the cloud parameter retrievals is examined by comparing the results for particles with smooth surfaces and rough surfaces. Retrieval results from two granules of MODIS data indicate that the retrieved cloud optical thickness is significantly reduced if the parameterization for roughened particles is used, as compared with the case of smooth particles. For the retrieval of cloud effective particle size, the inclusion of the effect of surface roughness tends to decrease the retrieved effective particle size if ice crystals are small. The reversed result is noticed for large ice crystals. It is also found that surface roughness has a very minor effect on the retrieval of cloud-top temperatures.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 125-136).

Thesis (Ph. D.)--University of Oregon, 2000. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 94-96). Also available for download via the World Wide Web; free to University of Oregon users.

Thèse de doctorat : Sciences des matériaux -Physique : Metz : 2007. / Thèse soutenue sur ensemble de travaux. Bibliogr. p.90-104. Appendice ( Abstract in Chinese) 39 p.

Reproduction de : Thèse doctorat : Génie civil : Cergy-Pontoise : 2005. / Thèse soutenue en co-tutelle avec l'Université de Sherbrooke (Canada). Titre provenant de l'écran titre. Bibliogr. p.175-181.

Thèse de doctorat : Science et Ingénierie des Matériaux : INPL : 2009. / Titre provenant de l'écran-titre.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 112-114).