摘要:
Disclosed is an optical fiber having a core with an alkali metal oxide dopant in an peak amount greater than about 0.002 wt. % and less than about 0.1 wt. %. The alkali metal oxide concentration varies with a radius of the optical fiber. By appropriately selecting the concentration of alkali metal oxide dopant in the core and the cladding, a low loss optical fiber may be obtained. Also disclosed are several methods of making the optical fiber including the steps of forming an alkali metal oxide-doped rod, and adding additional glass to form a draw perform. Preferably, the draw preform has a final outer dimension (d2), wherein an outer dimension (d1) of the rod is less than or equal to 0.06 times the final outer dimension (d2). In a preferred embodiment, the alkali metal oxide-doped rod is inserted into the centerline hole of a preform to form an assembly.
摘要:
A method of joining optical fiber preforms is disclosed wherein the optical fiber preforms are butt-welded by heating the opposing endfaces of the preforms with a heat source comprising an electric arc formed across a gap between the opposing endfaces, the electric arc being formed between at least two opposing electrodes, and thereafter contacting the opposing endfaces to join the preforms and form an elongated optical fiber preform. The elongated optical fiber preform may then be drawn into an optical fiber. Also disclosed is an apparatus for joining optical fiber preforms, and an optical fiber draw tower including the joining apparatus.
摘要:
An exercise rowing machine uses a flywheel as a resistance member and has cam sector arms which are pivoted to rotate with the machine's oars. A bicycle-type chain is pulled to drive a sprocket drive on the flywheel when the oars are stroked. The arcuate shape of the cam sector arms provides a constant resistance force to the stroke of the oars over the oar sweep. The position of the foot stretcher plate is adjustable. A shroud for the flywheel has an adjustable throttle or shutter to control air flow and thus adjust the amount of resistance.
摘要:
A device includes a temperature-sensitive material disposed between a first substrate and a second substrate. A metal-containing seal is disposed perimetrically between the first and second substrates. In addition, a method of forming a device includes providing a temperature-sensitive material between a first substrate and a second substrate. The method also includes applying an electromagnetic field, which inductively heats a metal-containing material that is disposed between the first and second substrates without heating the temperature sensitive material to a temperature greater than a threshold temperature.