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In this research, we studied the morphological transformation of a poly(4-vinylpyridine), P4VP, thin film on a polyimide substrate after thermal nanoimprint and investigated its effect on electron beam (EB) exposure by atomic force microscopy. On the basis of the results, we designed a patterned double-layer thin film consisting of polystyrene, PSt, as the outermost inactive layer and P4VP as the underlying active layer for Cu electroless deposition. We studied how to prepare and confirm the integrity of a double-layer structure on the polyimide substrate after thermal nanoimprint. A P4VP thin film of 60 nm thickness started to be transformed by thermal nanoimprint at 80 C owing to a thin-film effect lowering the glass transition temperature (T g ¼ 137 C) of its bulk state. EB exposure caused P4VP crosslinking and resulted in the P4VP layer becoming insoluble in toluene and being hardly transformed by thermal nanoimprint even at 160 C. As a result, an outermost layer of PSt exhibiting a lower T g than P4VP was successfully prepared by spin coating and was transformed only by thermal nanoimprint. The designed internal structure of the double-layer thin film patterned by thermal nanoimprint was confirmed by transmission electron microscopy (TEM) as a cross-sectional image using HAuCl 4 and RuO 4 as stain reagents for P4VP and PSt, respectively.

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The cleaning action with AC Tungsten Inert Gas (TIG) welding is attributed to the removal process of oxide film caused by cathode spots. In this study, a double shielding gas torch, which used the internal shielding gas of helium and the external shielding gas of helium or helium with 5.0 % oxygen, was employed to investigate influence of admixture of oxygen into the shielding gas on the cathode spot behavior in AC TIG welding. The cathode spots were photographed by a high-speed video camera and their distribution and velocity are discussed. Consequently, it was found that when the oxygen was mixed into the shielding gas, the number of cathode spots seemed to increase. Furthermore, the average velocity of cathode spots was considerably decreased to approximately 50 m/s near the center of the weld pool compared with 100m/s in case of pure helium shielding gas.