Abstract: A method of preparing preforms for optical fibers is provided. The method includes preparation of a first sol solution of a silicon alkoxide hydrolyzed with an acid and ultrafine particle silica, placement of the first sol solution into a container, and gelation of the first sol solution while the container is being rotated to yield a wet gel having a center hole. A second sol solution having a different composition than the first sol solution is prepared and used to fill the center hole in the wet gel. The second sol solution is then gelled to a wet gel composite and the composite is dried and sintered to yield the preform.

Abstract: A method of preparing tubular silica glass is disclosed. The method includes the steps of first hydrolyzing silicon alkoxide with acid and then adding ultra-fine particle silica to form a sol solution. The sol solution is placed in a cylindrical container and gelled while rotating the cylindrical container to obtain a tubular gel. The tubular gel is dried and sintered to the tubular silica glass.

Abstract: A method for preparing high quality silica glass articles is provided. The glass is prepared by hydrolyzing silicon alkoxide with a basic reagent to yield a first solution, hydrolyzing a silicon alkoxide with an acid reagent to yield a second solution, mixing the first solution with the second solution at a predetermined mixing rate to yield a sol solution, pouring the sol solution into a container, gelling the sol solution to a wet gel, drying the wet gel to a dry gel, and sintering the dry gel to yield a silica glass.

Abstract: Ester compounds suitable for use in liquid crystal compositions are provided. The ester compounds are (2'-chloro-4'-n-alkylphenyl)-3-cyano-4-n-alkoxybenzoates represented by the general formula: ##STR1## wherein R and R' are straight-chain alkyl groups having from one to eight carbon atoms. The ester compounds alone do not exhibit a liquid crystal phase, but have a relatively high value of dielectric anisotropy. Addition of minor amounts of at least one such ester compound to a liquid crystal composition lowers the value of the dielectric anisotropy of the composition in the high frequencies range. Such compositions are particularly well suited for the two-frequency matrix-addressing drive in a display of complex characters or graphic displays by reducing the driving voltage.

Abstract: An ester compound having the formula ##STR1## where R represents a normal alkyl group having one to eight carbon atoms. A method of synthesizing the compounds is presented. The compounds have relatively low melting points, and are particularly useful in combination with other liquid crystal compounds.

Abstract: Ester compounds suitable for use in liquid crystal compositions are provided. The ester compounds are (2'-cyano-4'-alkylphenyl)-3-cyano-4-n-alkoxybenzoates represented by the general formula: ##STR1## wherein R and R' each is a straight-chain alkyl group having one to eight carbon atoms. The ester compounds alone do not exhibit a liquid crystal phase, but have a relatively low melting point. Addition of at least one such ester compound to a liquid crystal composition lowers the value of the dielectric anisotropy of the composition at frequencies higher than the critical frequency, and lowers it at frequencies lower than the critical frequency. Such compositions are particularly well suited for the two-frequency matrix-addressing drive in a display of complex characters or graphic displays.

Abstract: Nematic liquid crystal compositions consisting of compounds having high stability with respect to moisture-resistance, oxidation-resistance and light-resistance, complete transparency and a wide range of operating temperatures are disclosed. The compositions are particularly useful for incorporation in a display device in a timepiece, and, more particularly, in a wristwatch. The compounds are mostly of the type wherein two benzene rings are joined by an ester group.

Abstract: A liquid crystal display device comprising a cell which rotates the plane of polarized light utilizing a composition of high dielectric anisotropy. The composition is stable and is at most only slightly absorptive of light.

Abstract: A liquid crystal display device uses nematic liquid crystal compounds having a high positive dielectric anisotropy for rotating the plane of polarized light. The optical activity of a composition including such materials can be eliminated by impressing a sufficiently high voltage across a cell containing such materials. These properties make it possible to use such compositions as the basis of a device which is, in effect, an optical shutter.