A nanomanipulation system operating inside a scanning electron microscope (SEM) enables visual observation and physical interactions with objects at the nanometer scale. Compared to SEM that is a powerful imaging platform (‘eyes’), the development of nanomanipulation systems (‘hands) and techniques for transporting, modifying, and interacting with micro/nanoscaled objects is lagging behind. Two generations of nanomanipulation systems were developed with high SEM compatibility. The vacuum load-lock feature allows setup/sample/end-tools changes to be made within minutes instead of hours as with existing nanomanipulation systems. The integrated high resolution encoders and automation features significantly ease the skill dependency in nanomanipulation. Its small shape factor minimizes effects on SEM imaging performance, and does not restrict the use of the many detectors inside a SEM. The new nanomanipulation systems were applied to the manipulation of sub-cellular structures and the characterization of nano-structures. The first application involves the development of a technique to surgically extract sub-micrometer-sized subnuclear structures within a single cell’s nucleus, followed by biochemical analysis to amplify and sequence the genes contained within. Enabled by the technique, four novel genomic loci associations with promyelocytic leukemia nuclear bodies (PML NB) were discovered in Jurkat cells. The second application targets automated probing of nanostructures under poor imaging conditions. Through real-time image drift compensation and visual servoing of the nano probes, automated probing of nanostructures was achieved with a high success rate and a speed at least three times higher than skilled operator. To enhance the functions of the nanomanipulation system, new types of end-effectors were also developed. A MEMS tool with changeable tool tips was design and prototyped. In-situ (i.e., inside SEM) tool tip change was demonstrated for gripping objects that vary in size by two orders of magnitude (15 um to 100 nm) with a single microgripper body. Furthermore, a microfabrication process was developed to produce changeable nano-spatulas with tip size less than 10 nm, intended for use in the subnuclear structure extraction work. Finally, a local precursor sublimation technique compatible with the nanomanipulation system was developed for enhancing electron beam induced deposition (EBID) inside the SEM.

A nanomanipulation system operating inside a scanning electron microscope (SEM) enables visual observation and physical interactions with objects at the nanometer scale. Compared to SEM that is a powerful imaging platform (‘eyes’), the development of nanomanipulation systems (‘hands) and techniques for transporting, modifying, and interacting with micro/nanoscaled objects is lagging behind. Two generations of nanomanipulation systems were developed with high SEM compatibility. The vacuum load-lock feature allows setup/sample/end-tools changes to be made within minutes instead of hours as with existing nanomanipulation systems. The integrated high resolution encoders and automation features significantly ease the skill dependency in nanomanipulation. Its small shape factor minimizes effects on SEM imaging performance, and does not restrict the use of the many detectors inside a SEM. The new nanomanipulation systems were applied to the manipulation of sub-cellular structures and the characterization of nano-structures. The first application involves the development of a technique to surgically extract sub-micrometer-sized subnuclear structures within a single cell’s nucleus, followed by biochemical analysis to amplify and sequence the genes contained within. Enabled by the technique, four novel genomic loci associations with promyelocytic leukemia nuclear bodies (PML NB) were discovered in Jurkat cells. The second application targets automated probing of nanostructures under poor imaging conditions. Through real-time image drift compensation and visual servoing of the nano probes, automated probing of nanostructures was achieved with a high success rate and a speed at least three times higher than skilled operator. To enhance the functions of the nanomanipulation system, new types of end-effectors were also developed. A MEMS tool with changeable tool tips was design and prototyped. In-situ (i.e., inside SEM) tool tip change was demonstrated for gripping objects that vary in size by two orders of magnitude (15 um to 100 nm) with a single microgripper body. Furthermore, a microfabrication process was developed to produce changeable nano-spatulas with tip size less than 10 nm, intended for use in the subnuclear structure extraction work. Finally, a local precursor sublimation technique compatible with the nanomanipulation system was developed for enhancing electron beam induced deposition (EBID) inside the SEM.

There is no abstract available for this thesis. / Department of Physiology and Health Science

Thesis (M.S.)--Brigham Young University. School of Technology, 2006. / Includes bibliographical references (p. 153-160).

Thesis (Ph.D.)--University of Melbourne, Dept. , 19. / Typescript (photocopy). Includes bibliographical references.

Thesis (Ph. D.)--University of Technology, Sydney, 2005.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 62-63). Also available in electronic version. Access restricted to campus users.

No description available.

No description available.

The goal of current research is probing the relationship between catalyst features and the fuel cell performance with a range of in-depth structural analysis. The study investigated different catalyst systems including core-shell structured catalyst, catalysts with unique carbon-transition metal oxide supports. PtRu catalysts nanoparticles with unique core-shell structure, one of the most practical catalysts in PEMFC technology, have been successfully obtained with the evidence from the characterization results. It is found that the enhanced CO oxidation may be achieved through the interactions between the Pt shell and Ru core atoms, which can modify the electronic structure of the Pt surface by the presence of subsurface Ru atoms or by disrupting the Pt surface arrangement. Furthermore, the possibility of presence of the compressive strain within the Pt rich shell is proved by the lattice measurements, which could significantly affect the catalytic activity. Pt catalysts supported on complex oxide and carbon support were studied to investigate the relationship between the catalyst and its support. Observations from STEM images and HAADF and energy dispersive X-ray spectrometry demonstrate the preferential distribution of Pt nanoparticles on the hybrid supports, which include Nb2O3 / C, Ta2O5 / C, (Nb2O3+TiOx) / C, (Ta2O5+TiOx) / C, and (WO3+TiOx)/C). Such evidence indicates the interaction between the catalyst and support is based on the presence of an interconnected oxide network over the carbon support and the presence of Pt strongly connected to the oxide network. In addition, using electron energy loss spectroscopy (EELS), the electronic structure of the catalyst support under various conditions was also studied to provide further evidence of the strong metal support interaction effect. / Thesis / Doctor of Philosophy (PhD)