Bacteriophage T4 was visualized using atomic force microscopy (AFM). The images were consistent with, and complementary to electron microscopy images. Head heights of dried particles containing DNA were about 75 nm in length and 60 nm in width, or about 100 nm and 85 nm respectively when scanned in fluid. The diameter of hydrated tail assemblies was 28 nm and their lengths about 130 nm. Seven to eight pronounced, right-handed helical turns with a pitch of 15 nm were evident on the tail assemblies. At the distal end of the tail was a knob shaped mass, presumably the baseplate. The opposite end, where the tail assembly joins the head, was tapered and connected to the portal complex, which was also visible. Phage that had ejected their DNA revealed the internal injection tube of the tail assembly. Heads disrupted by osmotic shock yielded boluses of closely packed DNA that unraveled slowly to expose threads composed of multiple twisted strands of nucleic acid. Assembly errors resulted in the appearance of several percent of the phage exhibiting two rather than one tail assemblies that were consistently oriented at about 72° to one another. No pattern of capsomeres was visible on native T4 heads. A mutant that is negative for the surface proteins hoc and soc, however, clearly revealed the icosahedral arrangement of ring shaped capsomeres on the surface. The hexameric rings have an outside diameter of about 14 nm, a pronounced central depression, and a center-to-center distance of 15 nm. Phage collapsed on cell surfaces appeared to be dissolving, possibly into the cell membrane.

Carpooling is one method that can be easily instituted and can help resolve a variety of problems that continue to plague urban areas, ranging from energy demands and traffic congestion to environmental pollution. However, most carpooling organizations currently use a trial-and-error process, in accordance with the projected vehicle travel times, for carpooling, which is neither effective nor efficient. In other words, stochastic disturbances arising from variations in vehicle travel times in actual operations are neglected. In the worst case scenario, where vehicle travel times fluctuate wildly during operations, the planned schedule could be disturbed enough to lose its optimality. Therefore, we constructed a stochastic carpooling model that considers the influence of stochastic travel times. The model is formulated as an integer multiple commodity network flow problem. Since real problem sizes can be large, it could be difficult to find optimal solutions within a reasonable period of time. Therefore, we develop a solution algorithm to solve the model. To test how well the model and the solution algorithm can be applied to the real world, we also developed a simulation-based evaluation method. To test the model and the solution algorithm, a case study is performed based upon data reported from a past study carried out in northern Taiwan. The results show that the model and solution algorithm are good and could be useful for carpooling practices.

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Periodic pyramidal array patterned sapphire substrate (PSS) with various inclined facets was fabricated by wet etching. It was found that {3true4̄17}, {41̄3̄18}, and {12true3̄5} facets are exposed on the PSS structure after etching. GaN grown on the PSS by metal-organic chemical vapor deposition was found to have a semi-polar orientation by structural characterization with scanning and transmission electron microscopy. Also, the results show that GaN is mainly grown on the {12true3̄5} sapphire facet with the orientation relationship between GaN and sapphire as (011̄4̄)GaN// (3true3̄0true6̄)sapphire and [02true2̄1]GaN // [11true2̄0]sapphire, and the dislocation density in the grown GaN decreased with thickness. In addition, photoluminescence and catholuminescence measurements show only strong near-band-edge emission from the semi-polar GaN on the {12true3̄5} sapphire facet.

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