Abstract: A membrane panel switch is disclosed wherein a sheet of extruded foam-molded polypropylene with apertures for switches has a thickness greater than 2 mm, a printed circuit board has a pair of contact elements disposed within the aperture, a clicking plate in the aperture contacts with one of the contact elements and is spaced from the other of the contact elements, the clicking plate has projections at ends thereof extending to an opening of the aperture from a bottom pf the aperture, a press plate in the aperture has a spherical upper surface and lower surface contacting the clicking plate, the press plate further has holes in where the projections are inserted and guided and an insulating layer coupled to the sheet extending over the aperture and over the spherical upper surface.

Abstract: A polymer obtained by the polymerization of a substituted 1,3-butadiene compound of the formula: ##STR1## wherein each of X.sub.1 and X.sub.2 is hydrogen or SiR.sub.1 R.sub.2 R.sub.3, provided that at least one of X.sub.1 and X.sub.2 is SiR.sub.1 R.sub.2 R.sub.3, wherein each of R.sub.1, R.sub.2 and R.sub.3 is halogen, lower alkyl or lower alkoxy, provided that R.sub.1, R.sub.2 and R.sub.3 are not lower alkyl at the same time.

Abstract: NO.sub.x is absorbed in an alkaline aqueous solution of a permanganate and/or a manganate and the manganese compounds are reduced to form the precipitate of manganese dioxide.The manganese dioxide is dispersed in an aqueous solution of sodium or potassium hydroxide having a concentration of higher than 20% and a gas containing NO.sub.x having a molar ratio of NO.sub.2 /NO.sub.x of higher than 0.55 is contacted with the dispersion in the presence of a permanganate and/or a manganate at higher than 40.degree. C, to convert manganese dioxide to the permanganate and/or the manganate.