An optical fiber according to an embodiment includes a core, a cladding, and a coating layer. At the boundary between the core and the cladding, the local sound velocity decreases in the direction from the core side toward the cladding side. At least in the cladding, the local sound velocity changes continuously in a radial direction. Further, the line width of the Brillouin gain of the light beam guided by the fundamental mode is 60 MHz or more.

The present invention relates to a transparent sealing member. A quartz glass transparent sealing member is used in an optical component having at least one optical element, and a mounting board on which the optical element is mounted, and constitutes, with the mounting board, a package that houses the optical element. The concentration of aluminum in a surface portion is higher than the concentration of aluminum in an inner portion.

To provide a glass composition which can be used for a dental porcelain or a dental ceramics coloring material, and has low temperature meltability, acid resistance and preservation stability under the humid environment which are required for a dental porcelain or a dental ceramics coloring material, and a dental porcelain and dental ceramics coloring material which contain the glass composition of the present disclosure. To provide a low melting glass composition with softening point (Ts) less than 600° C. comprising as a component; SiO.sub.2: 55.0 to 75.0 wt. %, B.sub.2O.sub.3: 6.1 to 12.0 wt. %, Al.sub.2O.sub.3: 2.0 to 8.0 wt. %, ZnO: 2.0 to 8.5 wt. % and two or more kinds of alkali metal oxide: 10.5 to 20.0 wt. %.

A secondary window includes a first glazing, a film, and a first frame. The first glazing includes a glass substrate having a thickness, between a first glazing surface opposite a second glazing surface, less than 2.0 millimeters. The film is attached to the first glazing surface. The first glazing is secured in the first frame, which at least partially surrounds the glazing. A second secondary window includes a second glazing secured in a second frame, which at least partially surrounds the second glazing. The second glazing includes (a) a first pane having a first-pane thickness less than 2.0 millimeters and (b) a second pane having a second-pane thickness that exceeds the first-pane thickness.

The present invention discloses a glass-ceramic article and a glass-ceramic for an electric device cover plate, the glass-ceramic comprises, as a predominant crystalline phase, lithium silicate and the quartz crystalline phase, and has a composition expressed in weight percent including: SiO.sub.2: 65-85%, Al.sub.2O.sub.3: 1-15%, Li.sub.2O: 5-15%, ZrO.sub.2: 0.1-10%, P.sub.2O.sub.5: 0.1-10%, K.sub.2O: 0-10%, MgO: 0-10%, ZnO: 0-10%, and Na.sub.2O: 0-5%, wherein (SiO.sub.2+Al.sub.2O.sub.3+Li.sub.2O+ZrO.sub.2)/P.sub.2O.sub.5 is 40-90, the falling ball test height is 700 mm or more. By reasonable component design, the present invention achieves excellent mechanical properties of the glass-ceramic and the glass-ceramic article of the present invention and obtains the glass-ceramic or the glass-ceramic article suitable for electronic devices at a lower cost.

An article includes SiO.sub.2 from about 40 mol % to about 80 mol %, Al.sub.2O.sub.3 from about 1 mol % to about 20 mol %, B.sub.2O.sub.3 from about 3 mol % to about 50 mol %, WO.sub.3 plus MoO.sub.3 from about 1 mol % to about 18 mol % and at least one of: (i) Au from about 0.001 mol % to about 0.5 mol %, (ii) Ag from about 0.025 mol % to about 1.5 mol %, and (iii) Cu from about 0.03 mol % to about 1 mol %, and R.sub.2O from about 0 mol % to about 15 mol %. The R.sub.2O is one or more of Li.sub.2O, Na.sub.2O, K.sub.2O, Rb.sub.2O and Cs.sub.2O. R.sub.2O minus Al.sub.2O.sub.3 ranges from about 12 mol % to about 3.8 mol %.

Provided is a porous glass member less likely to crack during production. A porous glass member has a porosity of 10 to 85% and contains, in terms of % by mass, 80 to below 100% SiO.sub.2, over 0 to 10% ZrO.sub.2, and 0 to 10% Al.sub.2O.sub.3.

A dust cover for an aerospace window that comprises dust cover having an exterior substrate and an interior substrate in a spaced apart relationship with a substantially transparent coupling agent therebetween. The dust cover is disposed in a spaced apart relationship from an electro-optic element, defining a gap therebetween. The gap 30 mm or less, 25 mm, 20 mm, 15 mm, 10 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3.5 mm, and/or 3 mm. The exterior substrate, the coupling agent, and the interior substrate are comprised of a combination of materials, such that the combination is substantially transparent and operable to resist breaking and maintain sufficient rigidity to prevent the electro-optic from breaking, when a force of 680 N is applied to an interior surface of the interior substrate in the direction of the electro-optic element.

One aspect relates to a process for the preparation of a quartz glass body, including providing a silicon dioxide granulate, wherein the silicon dioxide granulate was made from pyrogenic silicon dioxide powder and the silicon dioxide granulate has a BET surface area in a range from 20 to 40 m.sup.2/g, making a glass melt out of silicon dioxide granulate in an oven and making a quartz glass body out of at least part of the glass melt. The oven has at least a first and a further chamber connected to one another via a passage. The temperature in the first chamber is lower than the temperature in the further chambers. On aspect relates to a quartz glass body which is obtainable by this process. One aspect relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

A multilayer coil component includes a component element assembly in which an inner conductor is disposed and an outer electrode disposed on the surface of the component element assembly. The component element assembly includes a first dielectric glass layer in which the inner conductor is embedded and second dielectric glass layers that are thin layers disposed on respective principal surfaces of the first dielectric glass layer. The primary component of each of the first dielectric glass layer and the second dielectric glass layers is formed of a glass material and has a filler component containing at least quartz, and the second dielectric glass layers have a lower quartz content than the first dielectric glass layer.