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Nanowires and nanotubes with single component such as gold and nickel were fabricated by electrochemical deposition method directed by the Anodic Alumina Membrane (AAO) as a template. A so called "polymer-free" method has been investigated to make striped nanowires with superlattice structure. Various methods have been used to characterize these nanomaterials, including SEM, FESEM TEM, STM and Optical Microscope. The aggregation of the nanowires and their alignment under the magnetic force were observed under the optical microscope.

Biomedical research has shown that one-dimensional nanostructures present many potential advantages as delivery vehicles for drugs and biologics. These elongated structures have high aspect ratios that enable increased drug loading capacities and have been shown to have longer in vivo circulation times than other spherical nanoparticles. The increasing interest in these one-dimensional structures has necessitated the developments of fabrication methods for the precise control of the final morphology. A simple, cost effective means of producing nanotubes and nanorods is known as solution template wetting. While this technique has been used to fabricate many different types of elongated nanostructures, the parameters governing the final morphology remain ambiguous. The objectives of this research are to investigate these critical parameters, and furthermore to develop an understanding of the physical mechanism of nanostructure formation. The effects of the infiltration technique, dipping time, polymer molecular weight and template pore size on the morphology of the resulting nanostructure have been evaluated. Key results have established that the infiltration technique is a critical parameter that can enable the formation of stable nanotubes at very low polymer concentrations. Additionally, a tube to rod transition occurs as the infiltration time is increased over 18 hr. An investigation of the rheological properties of high and low molecular weight solutions also indicates that the capillary flow and infiltration of polymer occurs differently. Finally, the pore size was also shown to affect the ability to form hollow, stable structures, and that relatively large pore sizes are necessary for nanotube formation. The culmination of these results is an understanding of the physical layering mechanism of structure formation, and the tube to rod transition can thus be predicted by researchers investigating the use of elongated nanostructures for biomedical applications.

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With the advent of modern wireless communication techniques, mobile devices play an increasingly important role in our daily life. Users often use these mobile devices to record and retrieve information about tasks and data. In fact, many of people¡¦s daily activities are not independent, and they are likely to be process-oriented. Previous work reported in [Chen01] used metagraph to model user¡¦s activities and proposed a client-server architecture of personal workflow system for supporting pervasive computing. This architecture allowed users to define their personal processes and provided a set of operations for manipulating them. However, the proposed system is passive in that it did not provide any support to help mobile users construct their personal processes, nor did it provide friendly query interface for users. Our work aims at constructing a personalized workflow template provider and providing a user-friendly interface design. The personalized workflow template provider intends to provide personalized workflow templates of organization-driven processes. Users with different backgrounds and interests may retrieve different personal workflow template to accomplishing the same goal. In client side, we provide five pre-defined queries for mobile user can efficiently inquire a personal process and design a better interface for a mobile user to browse his/her personal processes. At last, we implemented these two components and evaluate the effectiveness of the proposed design strategies.

The zirconia is one of the transition metal oxides with a wide band-gap, showing many good mechanical and physical properties. This study concentrates on the preparation of the polystyrene template and the characterization of the ordered mesoporous zirconia thus prepared. The polystyrene (PS) templates have been prepared by the emulsifier-free emulsion polymerization of styrene monomer (SM) in mixed solution of K2S2O8 and H2O, without any cross-linking agent. The PS spheres so prepared have diameters ranging from 50 ¡V 400 nm. These spheres are then arranged in array by sedimentation method; then the infiltration of zirconia sol solution is followed. After the sol has been transformed to the gel, calcinations under high temperature are proceeded to remove the PS template to obtain the ordered mesoporous zirconia with various pore sizes. Doping of the zirconia also is conducted by applying an AgNO3 solution to the mesoporous zirconia. Results from SEM indicate that with a fixed ratio of K2S2O8/styrene = 5.98 wt¢H, the PS size decreases with the SM concentration; PS as small as 66 nm can be obtained when SM/H2O = 0.05¢H by volume. The PS spheres forms a hexagonal close packing when using a solution of H2O/ethanol = 3¡G7 by wt during sedimentation. Shrinkage ranging from 60 ¡V 80% of the original PS size happens when the PS template is removed from the calcined zirconia. Results from XRD indicate the same tetragonal crystalline structure of zirconia after calcinations at 500oC, regardless of the different pore sizes. BET measurements show the specific surface area of the zirconia from 6.05 - 42.61m2/g. For Ag-doped zirconia under hydrogen atmosphere, it is found from EDS mapping that the AgNO3 can be reduced to the metallic silver without particles aggregation but random distribution on the pore walls or surfaces, while the tetragonal crystalline structure of zirconia remains unaltered.

Proefschrift Rijksuniversiteit Groningen. / Met lit.opg. - Met samenvatting in het Nederlands.

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This study provides an investigation and discussion into the construction of a graph toolkit using generative programming techniques. It defines and analyses directed graphs, representations and identifies different techniques that may be used to discover new representations. Each representation is classified according to a unique classification system. Doing this enables us to uniquely identify a particular type of graph representation. A naming convention is used when identifying each graph representation which is a direct by product of the classification system. Details of how to implement the graph toolkit is presented and analysed. The toolkit is discussed and critically analysed with other major toolkits currently available today such as the Boost and Leda graph toolkits. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Computer Science / unrestricted