When mixed with imidazolium ion-based room-temperature ionic liquid, pristine single-walled carbon nanotubes formed gels after being ground. The heavily entangled nanotube bundles were found to untangle within the gel to form much finer bundles. Phase transition and rheological properties suggest that the gels are formed by physical cross-linking of the nanotube bundles, mediated by local molecular ordering of the ionic liquids rather than by entanglement of the nanotubes. The gels were thermally stable and did not shrivel, even under reduced pressure resulting from the nonvolatility of the ionic liquids, but they would readily undergo a gel-to-solid transition on absorbent materials. The use of a polymerizable ionic liquid as the gelling medium allows for the fabrication of a highly electroconductive polymer/nanotube composite material, which showed a substantial enhancement in dynamic hardness.

A novel strategy for the diversity-oriented synthesis of multisubstituted olefins, where 2-pyridyldimethyl(vinyl)silane functions as a versatile platform for olefin synthesis, is described. The palladium-catalyzed Heck-type coupling of 2-pyridyldimethyl(vinyl)silanes with organic iodides took place in the presence of Pd2(dba)3/tri-2-furylphosphine catalyst to give beta-substituted vinylsilanes in excellent yields. The Heck-type coupling occurred even with alpha- and beta-substituted 2-pyridyldimethyl(vinyl)silanes. The one-pot double Heck coupling of 2-pyridyldimethyl(vinyl)silane took place with two different aryl iodides to afford beta,beta-diarylated vinylsilanes in good yields. The palladium-catalyzed Hiyama-type coupling of 2-pyridyldimethyl(vinyl)silane with organic halides took place in the presence of tetrabutylammonium fluoride to give di- and trisubstituted olefins in high yields. The sequential integration of Heck-type (or double Heck) coupling and Hiyama-type coupling produced the multisubstituted olefins in regioselective, stereoselective, and diversity-oriented fashions. Especially, the one-pot sequential Heck/Hiyama coupling reaction provides an extremely facile entry into a diverse range of stereodefined multisubstituted olefins. Mechanistic considerations of both Heck-type and Hiyama-type coupling reactions are also described.

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The dynamic viscoelasticity of solutions of multi-arm star polystyrenes is investigated. The relaxation spectrum is calculated from the master curves of the dynamic storage and loss moduli. The relaxation spectra for the solutions as well as the melts exhibit a shoulder at long times. The relaxation intensity and the relaxation time for the long time relaxation are estimated from the relaxation spectra. The relaxation intensity strongly depends on the number density of the star molecules, suggesting that the number density dependence of the relaxation intensity is closely related with the degree of interpenetration between the star polymers, while the relaxation time of the long time relaxation is almost independent of the number density of the star molecules.

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An advanced IGBT with a new n+buffer structure has been developed. The new n+buffer structure is that some n+buried layers are formed at the boundary between a p+substrate and a n+buffer layer. The concentration of the n+buried layers is almost same as that of the p+substrate. The fabrication of the IGBT with the new n+buffer structure used a 3rd gen 600V/100A chip. Taking the W F inverter a y an application, total power loss generated to be about 12% less compared to the conventional IGBT, only changing n+buffer structure. And then the short circuit safe operating area of the new IGBT was almost similar to the conventional IGBT. Morever we discussed difference between the new IGBT and the conventional IGBT using a 3D simulator, DAVINCI .

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