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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

The effect of light intensity on the organic composition of marine phytoplankton diatoms

Marmelstein, Allan 18 July 1969 (has links)
Investigation was made into the influence of changing light intensity on the organic and elemental composition of two species of marine diatoms, Ditylum brightwellii and Skeletonema costatum. Analysis was made of the relative changes in soluble and insoluble carbohydrate; polar, non-polar, and total lipid; amino acids; proteins; and total carbon, hydrogen, nitrogen, and oxygen. Photosynthetic quotients were calculated from both organic and elemental composition. The response of soluble and insoluble carbohydrate was directly related to light intensity, although differences were noted between the two fractions. In general, amino acids and proteins showed little or no response to light intensity. Polar (pigment) lipids usually varied inversely with light intensity, whereas non-polar lipids varied directly with intensity. Total lipids also varied inversely with intensity although, considering the total amount of lipid present, the changes were slight. Some differences in relative organic composition were noted between the two species. On the basis of the data, average organic composition of each species was computed and compared with similar data in the literature. The effect of light intensity on the elemental composition of the two species yielded some differences, which were more readily apparent in the photosynthetic quotients calculated from elemental data. The photosynthetic quotient varied inversely with light intensity. Conclusions are summarized and suggestions for future research included. / Graduation date: 1970
102

The role of darkness in students' conceptions about light propagation and vision

Wells, Mary Anne. January 2007 (has links)
Thesis (M.Ed.)--University of Delaware, 2006. / Principal faculty advisor: Eric Eslinger, School of Education. Includes bibliographical references.
103

An approach to going higher than 1+1 dimensions with supersymmetric discrete light cone quantization

Harada, Motomichi, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 111-116).
104

Generation of soot particles and studies of factors controlling soot light absorption /

Lee, Keh-Tarng. January 1983 (has links)
Thesis (Ph. D.)--University of Washington, 1983. / Vita. Bibliography: leaves [115]-123.
105

Theoretical discussion of stimulated Rayleigh-wing scattering in liquids and liquid mixtures

Freeman, James A. Jr. January 1972 (has links) (PDF)
M.S. / Applied Physics / The theory of stimulated Rayleigh-wing scattering in anisotropic molecular liquids is discussed. This theory is extended to include liquid mixtures. When binary mixtures are considered, a singularity is found in the threshold condition in certain circumstances. This leads to the possibility of measuring the anisotropic polarizability difference for one of the liquids. In addition, the appearance of the singularity suggests a method of determining whether saturation plays an important role in stimulated Rayleigh-wing scattering.
106

Analysis for High Power Light Emitting Diodes Thermal Transmission

Chung, Cheng-fa 14 August 2007 (has links)
Nichia Corporation announced blue Light Emitting Diodes (LED) by 1993. They were widely used in markets by 1996 after combining blue LED with yellow phosphors to emit white lights. There¡¦re two keys to utilize LED as replacement light energy; one is to increase the chipset brightness, while another is to use LED arrays instead of single LED. Around 15 to 20% of LED illuminant will be transformed to visible light, while up to 85% of the LED illuminant will be transformed to heat. Therefore, before there¡¦s obvious breakthrough on LED constructions to heat, thermal management of LED is relatively important. The purpose of this research is to do value simulation by slightly change the construction of low power LED and increase its power (150, 350mA), to investigate the differences of high power LED in thermal transmission by single LED and LED arrays under different parameters, and learn if the emitted heat can be tolerated by its key materials. This research can be used as the reference to design LED products for engineers. According to the analysis result, under environment temperature of 25 to 80 Celsius Degree, the temperatures of a 0.5W LED chipset, mounted board and packing materials will increase around 3 to 4 Celsius Degrees when the environment temperature will increase one Celsius Degree. If we increase the LED chipset power to be 1W, the temperature increase for chipset and mounted board is around 3 to 4 Celsius Degrees while the temperature increase for packing materials is 3 to 9 Celsius Degrees. Regarding high power LED arrays, according to the analysis result, when the distance between two LEDs is too small, the temperature will increase dramatically; when the P value (see report content) is over 5mm, per 1mm distance increase, the chipset temperature decrease will become 1 to 2.5 Celsius Degrees from initially 3 to 5 Celsius Degrees. If we further increase the two LEDs distance, there¡¦ll be no significant effect from chipset itself but only the mounted board.
107

Angle- and Spectral-Dependent Light Scattering from Plasmonic Nanocups

Li, Yang 05 June 2013 (has links)
The interaction of light with small designed particles and structures gives rise to an increasing number of phenomena of potentially dramatic technological importance, such as metamaterials, superlens focusing, and enhanced spectroscopy. Metallic nanostructures with their geometry-dependent optical resonances are a topic of intense current interest due to their ability to manipulate light in ways not possible with conventional optical materials. A particularly fascinating aspect of these systems is the recently realized possibility of creating optical frequency “magnetic plasmon” responses of comparable magnitude to the “electric plasmon” response. Au nanocups at their magnetoinductive resonance have the unique ability to redirect scattered light in a direction dependent on cup orientation, as a true three-dimensional nanoantenna. As optical frequency nanoantennas, reduced-symmetry plasmonic nanoparticles have light-scattering properties that depend strongly on geometry, orientation, and variations in dielectric environment. Here we investigate how these factors influence the spectral and angular dependence of light scattered by Au nanocups. A simple dielectric substrate causes the axial, electric dipole mode of the nanocup to deviate substantially from its characteristic cos square free space scattering profile, while the transverse, magnetic dipole mode remains remarkably insensitive to the presence of the substrate. Nanoscale irregularities of the nanocup rim and the local substrate permittivity have a surprisingly large effect on the spectral- and angle-dependent light-scattering properties of these structures. The different angular scattering and wavelength response from the axial and transverse nanocup modes make the nanocup an interesting particle for the nanoscale manipulation of light in three dimensions. The sensitivity of this system to geometric and environmental factors may present opportunities for active, substrate-mediated control of light scattering.
108

Angle- and Spectral-Dependent Light Scattering from Plasmonic Nanocups

Li, Yang 05 June 2013 (has links)
The interaction of light with small designed particles and structures gives rise to an increasing number of phenomena of potentially dramatic technological importance, such as metamaterials, superlens focusing, and enhanced spectroscopy. Metallic nanostructures with their geometry-dependent optical resonances are a topic of intense current interest due to their ability to manipulate light in ways not possible with conventional optical materials. A particularly fascinating aspect of these systems is the recently realized possibility of creating optical frequency “magnetic plasmon” responses of comparable magnitude to the “electric plasmon” response. Au nanocups at their magnetoinductive resonance have the unique ability to redirect scattered light in a direction dependent on cup orientation, as a true three-dimensional nanoantenna. As optical frequency nanoantennas, reduced-symmetry plasmonic nanoparticles have light-scattering properties that depend strongly on geometry, orientation, and variations in dielectric environment. Here we investigate how these factors influence the spectral and angular dependence of light scattered by Au nanocups. A simple dielectric substrate causes the axial, electric dipole mode of the nanocup to deviate substantially from its characteristic cos square free space scattering profile, while the transverse, magnetic dipole mode remains remarkably insensitive to the presence of the substrate. Nanoscale irregularities of the nanocup rim and the local substrate permittivity have a surprisingly large effect on the spectral- and angle-dependent light-scattering properties of these structures. The different angular scattering and wavelength response from the axial and transverse nanocup modes make the nanocup an interesting particle for the nanoscale manipulation of light in three dimensions. The sensitivity of this system to geometric and environmental factors may present opportunities for active, substrate-mediated control of light scattering.
109

Stable Boron Subphthalocyanines: A Structure Property Relationship and New Processes for Further Synthetic Study

Brisson, Emma 05 December 2011 (has links)
A structure property relationship relating photostability with the axial and peripheral substituents of Boronsubphthalocyanine (BsubPc) derivatives has been outlined: peripherally halogenating BsubPc has been determined to be the best way to increase the photostability, while axial substituents are found to have little effect. A solid state photostability test using BsubPc doped polymer films has been developed and was used to form this structure property relationship. The polymer in which BsubPc is tested is found to have an effect on the photostability and should be further explored. In addition to the structure property relationship, processes to make new BsubPc precursors, HO-BsubPc and Br-BsubPc, have been developed in order to further expand the derivatives available for study.
110

Stable Boron Subphthalocyanines: A Structure Property Relationship and New Processes for Further Synthetic Study

Brisson, Emma 05 December 2011 (has links)
A structure property relationship relating photostability with the axial and peripheral substituents of Boronsubphthalocyanine (BsubPc) derivatives has been outlined: peripherally halogenating BsubPc has been determined to be the best way to increase the photostability, while axial substituents are found to have little effect. A solid state photostability test using BsubPc doped polymer films has been developed and was used to form this structure property relationship. The polymer in which BsubPc is tested is found to have an effect on the photostability and should be further explored. In addition to the structure property relationship, processes to make new BsubPc precursors, HO-BsubPc and Br-BsubPc, have been developed in order to further expand the derivatives available for study.

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