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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.
31

Measurement of low concentration and nano quantity hydrogen sulfide by carbon nanotube

Wu, Xiao Chu 17 December 2007 (has links)
Traditionally, hydrogen sulfide (H2S) has been regarded as toxic. It can affect the various human systems and even cause death. However, research in the 1990s has shown that H2S can be endogenously generated by many cells and tissues in mammalian bodies, and that H2S also may play physiological roles such as those of neuromodulator and vasorelaxant in the biological system. As such, the precise measurement of the amount of H2S in a mammalian body has generated researchers strong interest. The ultimate goal of such a measurement should be conducted in-vivo and in real time.<p>The existing methods for H2S measurement require both a large quantity of tissue samples and a complex procedure, so they are not highly practicable for the purpose of achieving the aforementioned goal. In this dissertation, a new method that uses carbon nanotube as an absorbent or transducer and laser-based microscopy techniques (Raman and confocal laser scanning microscopy) as signal excitation and acquisition is proposed and developed. Experimental studies are described of using this new method for analysis of both distilled water samples and serum samples in which a group of proteins are present. <p>The study concludes that the new method (1) can measure H2S in water solutions down to a low level of concentration of 10 µM, (2) can measure H2S in sera down to a low concentration of approximately 20 µM), and (3) has a high feasibility for being used in the clinical context. Regarding (3), this is confirmed by presenting a control system that allows the laser microscopy to track carbon nanotube in a solution that has Brownian motion.<p>While not having reached the ultimate goal as mentioned above, this work advances the state-of-the-art of the measurement of low concentration and nano-quantity of H2S in water and serum samples, in particular providing a promise toward a real-time and in-vivo H2S measurement.
32

Variable-temperature scanning tunneling microscopy studies of atomic and molecular level surface phenomena on semiconductor and metal surfaces /

Fitts, William Patrick, January 2001 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 337-351). Available also in a digital version from Dissertation Abstracts.
33

Computational modeling of stimulated emission depletion microscopy in biological cells under one- and two-photon excitation

Mark, Andrew Evan 03 February 2015 (has links)
The finite-difference time-domain method is used to simulate the propagation of focused beams used for stimulated emission depletion (STED) microscopy as they scatter through layers of biological cells. Depletion beams that facilitate axial and lateral confinement of the fluorescence emission are modeled, and the effective point spread function of the system as a function of focal depth is assessed under one- and two-photon excitation. Results show that the lateral depletion beam retains a well-defined minimum up to the maximum simulation depth of 42 µm. In addition, the relative spatial shift between excitation and de-excitation beam foci is less than 44 nm for all simulated depths. PSF calculations suggest that sub-diffraction imaging is possible beyond the maximum simulated depth, as long as the fluorescence emission is detectable. However, strong attenuation of the fluorescence emission by the axial confinement beam may make this beam unsuitable for sub-diffraction imaging in scattering samples. / text
34

Electric-field-induced second harmonic microscopy

Wu, Kui 28 August 2008 (has links)
Not available / text
35

Exploring Atomic Force Microscopy To Probe Charge Transport Through Molecular Films And For The Development Of Combinatorial Force Microscopy

Chisholm, Roderick A. Unknown Date
No description available.
36

Theoretical aspects of scanning transmission electron microscopy /

Findlay, Scott David. January 2005 (has links)
Thesis (Ph.D.)--University of Melbourne, Dept. of Physics, 2005. / Typescript. Includes bibliographical references (leaves 205-223).
37

Development of spectral imaging microscope for single molecule studies in complex biological systems /

Girirajan, Thanu Prabha Kalambur, January 2007 (has links)
Thesis (M.S.) in Electrical Engineering--University of Maine, 2007. / Includes vita. Includes bibliographical references (leaf 75).
38

Crossed and uncrossed retinal fibres in normal and monocular hamsters : light and electron microscopic studies /

Yu, Enhua. January 1990 (has links)
Thesis (Ph. D.)--University of Hong Kong, 1991.
39

The point emitter as a positive-ion source

Herron, Russell Gardner. January 1955 (has links)
Thesis (M.S. in Physics)--United States Naval Postgraduate School, California. / Includes bibliographical references (p. 23). 9
40

Development of Spectral Imaging Microscope for Single Molecule Studies in Complex Biological Systems

Girirajan, Thanu Prabha Kalambur January 2007 (has links) (PDF)
No description available.

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