Abstract: [Object] In manufacturing a GRIN lens by a sol-gel method, an operation for preparing a wet gel is facilitated and cracking in a base material during sintering and foaming during drawing are prevented. [Solution] The object is achieved by obtaining a GRIN lens by producing a wet gel from an alcohol solution containing a silicon alkoxide, a dopant alkoxide, and a boron alkoxide as the main ingredients, leaching the same, drying the same to form a dry gel, and sintering and drawing the same.

Abstract: A method is provided for forming an optical fiber amplifier. The method comprises providing a composite preform having a gain material core that includes one or more acoustic velocity varying dopants to provide a longitudinally varying acoustic velocity profile along the gain material core to suppress Stimulated Brillouin Scattering (SBS) effects by raising the SBS threshold and drawing the composite preform to form the optical fiber amplifier.

Abstract: It is disclosed a method for making SPME fibers. The SPME fibers consist of metal-oxide coatings on fused-silica fibers. The coatings are prepared from a water-based solution containing a predetermined amount of metal ion and a predetermined amount of a reactant. The water based solution and the fused-silica fibers are kept at the temperatures below 100° C. for a predetermined time to obtain SPME fibers. The SPME fibers are applied for extraction of pesticides and other organic compounds such as 1,4-dichloro-2-nitrobenzene; Biphenyl; and Acenaphthene in the water based solution and cooling gas of a power generator respectively.

Abstract: A method for manufacturing a GRIN lens includes the steps of forming a wet gel provided with a concentration distribution having a different concentration of a refractive index distribution imparting metal that differs in concentration in a radial direction, drying the wet gel to form a dry gel having a bulk specific gravity ? (g/cm3), sintering the dry gel to form a GRIN lens base material and stretching the GRIN lens base material while heating. The method is characterized in that, in the step of sintering the dry gel, partial pressures of oxygen during sintering at 800° C. or higher are 10?1 Pa or lower and also the relation between a rate of temperature increase v (° C./hr) and a bulk density ? of the dry gel during sintering at 1,000 to 1,150° C. is defined by v?105*EXP (?12?). As a result of this, the GRIN lens, which has a large numerical aperture and a small diameter, can stably and easily be manufactured.

Abstract: In a production process of an organic-inorganic hybrid glassy material, the invention relates to a process for producing an organic-inorganic hybrid glassy material, characterized in that the process comprises at least the three steps of producing a gel body by a sol-gel method; melting by heating; and aging, and it relates to an organic-inorganic hybrid glassy material produced by this process.

Abstract: An intermediate preform is formed in a process of manufacturing an optical fibre by forming a sol containing a glass precursor; pouring the sol in a mold containing a set of elongate elements; aging the sol to obtain a gel body; removing the set of elongate elements from the gel body to create a corresponding set of holes in the gel body; and removing the gel body from the mold. The method further provides imparting a motion of the set of elongate elements during aging of the sol to avoid adhesion of the gel to the elongate elements, the motion being preferably a rotation about the respective axes or an alternate translation along the respective axes. An apparatus with means for carrying out the method is also described.

Abstract: A method of forming a ceramic fiber comprising the steps of forming a slip comprised of water, ceramic powder, and a binding agent; forming a generally continuous stream of the slip; introducing the stream of the slip into a chemical solution at a concentration wherein the binding agent causes the ceramic slip to form a gelled fiber; removing the gelled fiber from the chemical solution; drying the gelled fiber to remove moisture therefrom; and firing the fiber to produce a ceramic.

Abstract: It is disclosed a method for making SPME fibers. The SPME fibers consist of metal-oxide coatings on fused-silica fibers. The coatings are prepared from a water-based solution containing a predetermined amount of metal ion and a predetermined amount of a reactant. The water based solution and the fused-silica fibers are kept at the temperatures below 100° C. for a predetermined time to obtain SPME fibers. The SPME fibers are applied for extraction of pesticides and other organic compounds such as 1,4-dichloro-2-nitrobenzene; Biphenyl; and Acenaphthene in the water based solution and cooling gas of a power generator respectively.

Abstract: A refrigerator having an air-cleaner is provided. The refrigerator includes a main body with a predetermined storage space defined therein, and an air-cleaner including a case fixed to the main body and having at least an inlet and outlet, a decor panel that linearly reciprocates to selectively open and close the outlet, a filter device that filters air sucked through the inlet, a blower that sucks air through the inlet and discharges the air filtered in the filter device through the outlet, and an anion generator that generates anions which are discharged along with the air through the outlet. The air-cleaner is securely mounted to the upper surface of the refrigerator.

Abstract: Carbon particles, such as, carbon fibrils and carbon nanotube molecules, are assembled into aligned fibers using processes derived from the processes used to manufacture optical fiber. More particularly, the carbon particles are embedded in glass, which is then drawn to align them. By aligned it is meant the axis along the longest dimension of each of the various particles in a local vicinity are substantially parallel.

Abstract: The present invention is directed to method of bonding mineral fibers in a mineral fiber material, according to which an acid is applied to the mineral fiber material in an amount sufficient to dissolve mineral material from the fiber to form a silica containing binder on the mineral fiber, and curing the mineral fiber material to bond the fibers.

Abstract: Silica sol techniques are described for making thick silica or silica based films useful for planar optical waveguides. The process involves coating of a colloidal silica sol onto a substrate, drying the sol, and consolidating the dried sol to form the planar waveguide. Coating is performed in a simple operation, either by dipping, or preferably by spin coating. In a preferred embodiment the substrate is coated with a wetting agent prior to spin coating. It is found that the wetting agent substantially improves the thickness uniformity of the layer. Thick waveguide layers may be produced by repeating the coating process one or more times to produce a layer with the desired thickness. Buried waveguides are produced by forming a doped core layer, patterning the doped core layer and using the coating technique of the invention to form the cladding material.

Abstract: The invention relates to a method for manufacturing optical glasses and colored glasses with the aid of a fluid phase sintering process from a basic material encompassing at least SiO.sub.2 powder as well as additives for reducing the temperature of the fluid phase sintering and/or melting process encompassing the following steps: the starting materials are dissolved in any sequence in a fluid medium to produce a solution as far as is possible and a suspension to the extent that they are not dispersed in solution; a greenbody is produced from the dissolved and dispersed starting materials; the greenbody is dried the dried greenbody is fluid-phase sintered at temperatures below 1200° C., in particular in the temperature range from 600° C. to 1200° C.

Abstract: A hydrous silica gel is dehydrated by freezing, thawing, and removing water separated by thawing, thereby yielding silica particles. In addition, the silica particles thus formed is washed and fired, thereby producing a synthetic quartz glass power. A water glass is dealkalized, an oxidizing agent and an acid are added, the mixture thus formed is passed through a hydrogen type cation exchange resin, the aqueous silica solution thus formed is then gelled, and the gelled material is then washed and fired, thereby producing a synthetic quartz powder. Silica is sequentially held for a predetermined time at each temperature range of 150 to 400° C., 500 to 700° C., and 1,100 to 1,300° C., thereby producing a quartz glass.

Abstract: A simple, economic wet chemical procedure is described for making sol-gel fibers. The sol-gel fibers made from this process are transparent to ultraviolet, visible and near infrared light. Light can be guided in these fibers by using an organic polymer as a fiber cladding. Alternatively, air can be used as a low refractive index medium. The sol-gel fibers have a micro pore structure which allows molecules to diffuse into the fiber core from the surrounding environment. Chemical and biochemical reagents can be doped into the fiber core. The sol-gel fiber can be used as a transducer for constructing an optical fiber sensor. The optical fiber sensor having an active sol-gel fiber core is more sensitive than conventional evanescent wave absorption based optical fiber sensors.

Abstract: Sol-gel process for the production of optical fiber preforms or overcladdings by preparing a sol, gelling the sol, drying the wet gel to a dry porous gel and densifying the dry gel to fully dense glass, wherein during the calcination treatment from 350° C. to 900° C. to remove organic impurities in the dry gel, it is carried out at least one reduced-pressure phase at a pressure comprised between about 0.01 and 0.5 bar.

Abstract: The present invention discloses a process for making rare earth (RE) doped optical fiber by using RE oxide coated silica nanoparticles as the precursor material, more particularly the method of the present invention involves preparation of stable dispersions (sol) of RE oxide coated silica nanoparticles at ambient temperature and applying a thin coating on the inner surface of silica glass tube following dip coating technique or any other conventional methods, of the said silica sol containing suitable dopants selected from Ge, Al, P, etc.

Abstract: Pyrogenically prepared silicon dioxide with the following physicochemical properties: 1. Average particle size (D50 value) D50?150 nm (dynamic light scattering, 30 wt %) 2. Viscosity (5 rpm, 30 wt %) ??100 m·Pas 3. Thixotropy of Ti (?(5 rpm))/(?(50 rpm))?2 4. BET surface area 30-60 m2/g 5. Compacted bulk=100-160 g/L 6. Original pH?4.5 that can be used for the preparation of dispersions and glass bodies.

Abstract: The invention relates to inorganic hollow fibers, to a spinning mass and to a method for producing the same as well as to the use thereof for material transports, for the exchange of gases and in separation procedures. The hollow fibers according to the invention are obtainable by processing a spinning mass to a hollow fiber according to general methods, by curing said fiber thermally, via radiation induction or via chemical induction, and by removing the organic components via pyrolysis. The spinning mass is obtained by hydrolytic polycondensation of hydrolyzable compounds of silicon, aluminum, titanium and zirconium and optionally of co-condensable compounds of the elements Li, Na, Mg, Ca, Sr, Ba, Zn, Sn or Pb. The hydrolytic polycondensation is performed by adding water or moisture.

Abstract: A method of fabricating a halogen-doped glass includes providing a gel monolith having a first halogen content. The method further includes reducing an impurity concentration of the gel monolith. The method further includes consolidating the gel monolith into a glass having a second halogen content. The second halogen content is less than or equal to the first halogen content. A halogen-doped glass has a fluorine content in a range between approximately 0.5 wt. % and approximately 4 wt. %, a chlorine content less than 100 parts per million, and an OH content less than one part per million.

Abstract: A sol-gel process is described that allows dry gels to be produced, and where necessary, the corresponding dense vitreous bodies, around an incompressible insert. A particular feature of the process is the step of rotating a container holding the sol and incompressible insert throughout the gelling step under such conditions that a wet gel adhering to the insert is produced, which is then dried. The process is useful particularly for the production of preforms for optical fibers, which are also claimed.

Abstract: The present invention discloses a process for making rare earth (RE) doped optical fibre by using RE oxide coated silica nanoparticles as the precursor materia, more particularly the method of the present invention involves preparation of stable dispersions (sol) of RE oxide coated silica nanoparticles at ambient temperature and applying a thin coating on the inner surface of silica glass tube following dip coating technique or any other conventional methods, of the said silica sol containing suitable dopants selected from Ge, Al, P, etc.

Abstract: The present invention relates to a preform for a glass ferrule and a fabrication method thereof. It is an objective of the present invention to fabricate dual hole ferrules having various distances between two holes by using a single preform. It is another objective of the present invention to fabricate a preform for a dual hole glass ferrule by a simple process. To meet the above and other objectives, the present invention provides a preform for a glass ferrule, comprising two holes which are formed through the preform and exit out both side cross-sections of the preform, wherein the two holes are symmetrical to the center in a diameter direction of the preform and a distance between the two holes changes in a lengthwise direction of the preform.

Abstract: Disclosed are novel silica gel nanofibers having an outer diameter lower than 100 nm, a length of up to 1 cm, a specific surface area of from 600 to 1000 m2/g and pore diameters of from 2 to 10 nm. Also disclosed are novel silica glass nanofibers having an outer diameter and a length similar to that of the above silica gel fibers. The silica gel nanofibers are prepared by reacting chrysotile in an aqueous solution containing a controlled-proton-releasing agent and cation-complexing agent, whereby the cations of the silicate are replaced by protons and dissolved, with production of solid fibrous and amorphous hydrated silica. The silica glass nanofibers are made by dehydrating the silica gel nanofibers at temperatures close to 1000° C. These nanofibers have numerous potential applications, especially due to their capacity to adsorb or absorb ions and metals, especially catalytically useful metals such as copper and silver.

Abstract: A composition for production of silica glass using a sol-gel process is described, comprising silica particles, a dispersing agent, and a solution containing a polymerizable monomer for formation of acrylic resin and a crosslink agent dissolved in distilled water. The polymerizable monomer is n-methylol acrylamide or n-methylol methacrylamide. A method for production of silica glass is described, including the step of adding silica particles and a dispersing agent to a premix solution of the polymerizable monomer for formation of acrylic resin and the crosslink agent dissolved in distilled water.

Abstract: Sol-gel process for the production of optical fiber preforms or overcladdings by preparing a sol, gelling the sol, drying the wet gel to a dry porous gel and densifying the dry gel to fully dense glass, wherein during the calcination treatment from 350° C. to 900° C. to remove organic impurities in the dry gel, it is carried out at least one reduced-pressure phase at a pressure comprised between about 0.01 and 0.5 bar.

Abstract: A process for manufacturing an inorganic material-based article comprising the steps of

Abstract: Disclosed are apparatus and method for ultrasonically dispersing a silica sol such as is used in a process of manufacturing a silica glass by a sol-gel method. The apparatus includes a sol feeder for holding a sol to be dispersed, a sol container for containing the ultrasonically dispersed sol, a medium tank having a liquid-phase ultrasonic medium, an ultrasonic vibrator for generating ultrasonic waves within the tank, and a sol pipe for providing a sol feeding path connecting the sol feeder and the sol container to each other, the sol pipe having a portion submerged under the ultrasonic medium in the medium tank. The portion of the sol pipe submerged under the ultrasonic medium has a shape bent in a zigzagged fashion.

Abstract: A fabrication method of graded index silica glass is disclosed. The method according to the present invention includes the steps of dispersing to form sol by mixing a starting material with a dispersion medium; molding the sol into a moisturized gel with a predetermined shape using a molding frame and separating the moisturized gel from the molding frame; drying the moisturized gel under a predetermined temperature and humidity level to remove the dispersion medium and to form a first dry gel having a predetermined moisture content distribution, hydrolyzing the moisture remained in the first dry gel and an additive solution by putting the first dry gel into the additive solution; re-drying the first dry gel, which underwent said hydrolysis, to form a second dry gel; and, thermal processing the second dry gel by supplying reaction gas thereto, removing impurities therefrom and annealing for isolation.

Abstract: A sol-gel method of preparing a powder for use in forming a glass is provided, along with methods of preparing glasses and glass fibers from the powder. The inventive method allows for the incorporation of a wide range of elements and compositions into a homogeneous glass or glass fiber that is substantially free of hydroxide groups. In addition, dopants incorporated into glasses prepared by the inventive method are uniformly distributed throughout the glass structure.

Abstract: A multicomponent particulate gel includes 80-100 mole % SiO2, 1-10 mole % X2O, 1-10 mole % YO, 1-15 mole % Al2O3, and 0.1-5.0 weight % Er2O3,where X represents lithium, sodium, potassium, or mixtures thereof and Y represents calcium, barium, magnesium, lead or mixtures thereof, and the ratio of Al2O3 to (X2O+YO) is between about 0.9 and about 2.5. A process of manufacturing the gel includes hydrolyzing alkoxide derivatives of silicon, aluminum, erbium, lithium, sodium, potassium, calcium, barium, magnesium, lead or mixtures thereof in water to generate their respective hydroxide derivatives; polymerizing the hydroxide derivatives to produce a gel slurry comprising an essentially silica network; and drying the gel slurry to produce the gel.

Abstract: Disclosed is a method for fabricating high-purity silica glass using a sol-gel processing that includes the steps of: (a) mixing a deionized water with a fluorine compound and a dispersion agent to prepare an aqueous premix solution; (b) mixing the aqueous premix solution with a fumed silica; (c) mixing the resulting mixture to form a dispersed sol; (d) aging the sol at the ambient temperature to stabilize silica particles; and, (e) removing air voids from the sol and adding a gelation agent.

Abstract: Disclosed is a method for fabricating high-purity silica glass using a sol-gel processing that includes the steps of: (a) mixing deionized water with a monomer and a dimer to prepare an aqueous premix solution; (b) mixing the aqueous premix solution with a fused silica and a dispersion agent; (c) mixing the resulting mixture to form a dispersed sol; (d) aging the dispersed sol at the ambient temperature to stabilize silica particles, and removing air voids from the sol; and, (e) adding a polymerization initiator and a gelation agent to the aged sol.

Abstract: The invention reflects discovery of a liquid phase doping technique that, unlike previous techniques, exhibits very little fluorine depletion upon subsequent heating. The invention involves the steps of providing a silica sol comprising a tetraalkylammonium hydroxide and a di-, tri-, or tetraalkylammonium fluoride, the sol having pH of about 10 to about 14, adding a gelling agent to the sol to induce gelation, casting or extruding the sol to form a gel body, and then drying, heat treating, and sintering the body. Advantageously, the fluorine-containing compound is tetramethylammonium fluoride.

Abstract: A process for producing a synthetic quartz powder, which comprises a step of heat-treating a silica gel powder while permitting it to flow in a rotary kiln.

Abstract: A synthetic quartz glass powder obtained by sol-gel method, wherein the number of black spot particles is at most 5 particles per 50 g, provides a high quality quartz glass shaped product with low bubble content when fused.

Abstract: A silica glass monolith fabricating method using a sol-gel process. In the method, a first sol is formed by mixing 100 parts by weight of high-density silica containing powder with 100-300 parts by weight of water, and rapidly dried, while the pH of the first sol is being controlled in the range between 9 and 11. The dried first sol is powdered and then thermally treated at or above 600.degree. C., and a second sol is formed by mixing the thermally-treated powdered first sol with 100-200 parts by weight of deionized water and a aqueous organic binder. The second sol is gelled in a mold, dried, thermally treated, and sintered. Thus, a high-purity silica glass monolith is obtained.

Abstract: A method for fabricating a silica glass is provided. The method includes the steps of adding silica and a dispersant to a premix solution obtained by dissolving an acrylic resin monomer and a cross-linking agent in distilled water, dispersing the mixed solution and adjusting the pH of the mixture, to form a sol. Air bubbles are removed from the sol, and then the resultant sol is aged. A polymerization initiator and a catalyst are added to the aged sol, and the pH of the reaction mixture is adjusted. The reaction mixture is poured into a mold, and then the mixture is gelated, aged, demolded, dried, and then thermally treated to remove organic substances. Hydroxy groups are eliminated and the gel is sintered. A high purity silica glass tube, substantially free of cracking after drying and having a low shrinking ratio can be obtained. Also, a large silica glass tube can be manufactured by this fabrication method.

Abstract: A porous body containing a silicon component as a starting material of optical element is immersed in a solution containing hydrofluoric acid, taken out from the solution and immersed in a solution containing a metal alkoxide containing a first metal component except silicon or a derivative thereof so that the porous body contains the first metal component in such a concentration gradient that the concentration of the first metal component decreases from a periphery of the porous body toward a center of the porous body. Hydrofluoric acid breaks glass bonds of the porous body, so that the concentration of the first metal component can be securely distributed in a desired gradient. Drying and sintering of the porous body enables producing, for example, a glass having a metal component concentration concavely distributed in its radial direction which is excellent in chromatic aberration suppressing capability.

Abstract: The invention provides a process for making a gradient index optical element having a precisely parabolic configuration of refractive index profile. After a concentration profile is imparted across a gel prepared by a sol-gel technique, the concentration profile is fixed. In this case, the treatment with a concentration profile-fixing solution is carried out at a temperature higher than that at which the treatment with a concentration profile-imparting solution is carried out, whereby the rate of fixing the concentration profile is so higher than that of imparting the concentration profile, so that any possible deformation of the concentration profile formed at the concentration profile-imparting step is reduced or inhibited.

Abstract: A glass with no stria form of defects induced therein is produced by a sol-gel technique. At a sol gelation step, the gelation temperature is maintained constant within the range of .+-.7.degree. C. with respect to the temperature of a sol as charged in a gelation vessel, and the sol is gelated at a constant colloidal particle diameter with no vibrations applied thereto.

Abstract: A gradient index optical element is disclosed which comprises a surface perpendicular to an optical axis, this surface having points of equal refractive index whose connection provides substantially elliptic lines. This gradient index optical element can be produced, for example, by first pouring a raw material sol into a vessel suited for preparing a rodlike base material comprising a surface perpendicular to its lengthwise direction, said surface having the shape of a rectangle, a rhombus or a polygon symmetrical with respect to its center of gravity, each as is, or having a rounded or elliptical corner subsequently converting the sol to a gel, then subjecting the gel to distribution providing treatment and finally drying and firing the distribution providing gel.

Abstract: Synthetic quartz glass powder is produced by (a) hydrolyzing an alkoxysilane to form a gel, (b) finely dividing the gel and then drying, or drying the gel and then finely dividing, and (c) calcining the obtained powder, the powder being maintained under an atmosphere with an oxygen concentration of not less than 30 vol % during at least a part of the calcining period at a temperature of not lower than 1,000.degree. C.