Spontaneous formation of highly ordered nanostructures: thermal instability and mode selection in surface-capped polymer films.

We demonstrate a controllable formation process of wave-like patterns in thermally unstable surface-capped polymer films on a rigid substrate. Self-ordered wave-like structures over a large area can be created by applying a small lateral tension to the film, whereupon it becomes unstable. A clear mode selection process which includes creation, decay and interference between coexisting waves at different annealing conditions has been observed, which makes it possible to restrain the patterns which are formed finally. Our results provide a clear and new evidence of spinodal behaviour in such a film due to thermal instability. Furthermore, we show that the well-controlled patterns generated in such a process can be used to fabricate nanostructures for various applications.

Computer-based selection of joining processes

The assembly of any manufactured product involves joining. This paper describes ways of selecting processes for joining. The method allows discrimination of the joint geometry, joint loading, material, and other attributes of the joint itself, identifying the subset of available processes capable of meeting a given set of design constraints. A relational database containing data-tables for joining processes, materials to be joined, and joint geometry and mode of loading, allows the attributes of each of these to be stored in an appropriate format, and permits links to be created between those that are related. A search engine isolates the processes that meet design requirements on material, joint geometry and loading. The method is illustrated in Part 2 by case studies, utilising software that embodies the method.