Abstract: The invention provides an article comprising a solder that bonds well to oxides and other surfaces to which solder bonding is problematic. The solder composition contains one or more rare earth elements, which react with the oxide or other surface to promote bonding, and further contains sufficient Au and/or Ag to act as carriers for the rare earths. Because rare earths have some solid solubility in Au and Ag, the problem of intermetallic formation is lessened or eliminated, and improved bonding to oxide surfaces is attained.

Abstract: An improved process for fabricating a refractory dielectric article, in particular silica optical fiber, is provided. The fabrication process involves joining of two elongated bodies—typically silica preforms—end-to-end by use of an isothermal plasma torch technique. A long preform made in this manner allows drawing of optical fiber with less down-time and waste than current processes. The plasma torch technique also produces low perturbations within the resultant preform, thereby increasing the amount of usable fiber.

Abstract: An article comprising an alloy exhibiting high magnetostriction in relatively low applied magnetic fields is provided, the alloy capable of being formed in a relatively easy manner and having desirable physical properties. The Co—Fe alloy of the invention exhibits a magnetostriction of at least 100×10−6 in a magnetic field less than 400 Oe, advantageously in a magnetic field less than 100 Oe. The alloy is formed by plastically deforming the alloy, e.g., by cold rolling, to a reduction in cross-sectional area of at least 50%, and then heat treating the alloy to induce recrystallization. This combination of plastic deformation and recrystallization was found to provide desirable grain growth and microstructure. The resultant alloy is useful in a variety of device components, including transducers, frequency filters, signal delay lines, and optical fiber grating devices.

Abstract: A small sample of a refractory material, e.g., about 0.1 g to about 10 g, is heated to at least 1000° C., generally under a pressure of less than about 10−5 Torr. Evolved hydrogen-containing gases and/or carbon-containing gases are monitored, e.g., by mass spectrometry, and, based on the amount of the evolved gases, the concentration of hydrogen and/or carbon in the sample is calculated. It is therefore possible to accurately determine the hydrogen and carbon concentration from a small sample of a material, by a process much less burdensome than conventional techniques.

Abstract: The emission properties of aligned nanotube arrays are improved by truncating the ends of the nanotubes. Truncation provides nanotubes having a height within, for example, 30% of the average truncated nanotube height, as well as ends substantially free of end caps. The cap-free ends provide desirable field concentration, and the height uniformity increases the number of participating nanotubes.

Abstract: A method for fabricating adherent, patterned carbon nanotube films is provided. According to the invention, a substrate is patterned with a carbide-forming material, a carbon-dissolving material, or a low melting point metal. Carbon nanotubes are then deposited onto the patterned substrate, but have relatively poor adhesion to either the substrate material or the patterned material. The substrate is then annealed, typically in vacuum, at a temperature dependent on the particular patterning material, e.g., a temperature at which carbide formation occurs, at which carbon dissolution occurs, or at which the low melting point metal melts. The annealing thereby provides an adherent nanotube film over the patterned areas, while the nanotubes deposited onto the non-patterned areas are easily removed, e.g., by blowing, rubbing, brushing and/or ultrasonication in a solvent such as methanol.

Abstract: An improved photorecording medium suitable for use in holographic storage systems contains a glassy hybrid inorganic-organic, three dimensional matrix, in which is distributed a photoimageable system comprising one or more photoactive, organic monomers. The medium is fabricated by providing a precursor of the hybrid inorganic-organic matrix, mixing the matrix precursor with the photoimageable system, and curing the matrix precursor to form the matrix in situ. The matrix and photoimageable system exhibit independent chemistries, such that the step of matrix formation does not substantially affect the photoimageable system. The hybrid matrix precursor is typically an oligomer derived from a compound represented by RnM(OR′)4−n, where M is a metallic element having a valence of three or higher, such as silicon, titanium, germanium, zirconium, vanadium, or aluminum, R is an alkyl or aryl, R′ is a lower alkyl, and n ranges from 1 to 2.

Abstract: An organic semiconductor film is fabricated by applying a solution containing an organic semiconductor material and a solvent to a substrate, e.g., by solution casting, and evaporating the solvent. The characteristics of the substrate surface, the organic semiconductor material, and the process parameters are selected to provide desirable nucleation and crystal growth. The resultant organic semiconductor film contains a large area, e.g., a continuous area greater than 1 cm2, that exhibits a relatively high charge carrier mobility of at least about 10−4 cm2V−s−1 at room temperature.

Abstract: An improved process for fabricating nanotube field emitter structures is provided, in which the nanotubes protrude from a supporting base material to improve emission properties. The resulting emitter structure are useful in a variety of devices, including microwave vacuum tube devices and flat-panel, field-emission displays. To attain the protruding nanotube emitter structure, according to one embodiment of the invention, nanotubes and metal particles are mixed and consolidated into a compact, and the compact is then sectioned to expose a substantial number of nanotube ends. A layer of the metal is selectively etched from the sectioned surface, leaving the exposed nanotubes protruding from the surface. The extent of protrusion is at least twice the average diameter of the nanotubes, advantageously at least ten times the average diameter of the nanotubes.

Abstract: The invention provides a device comprising an oriented, perovskite PZT layer on a diamond substrate, or other substrates such as silicon or platinum-coated materials. Vapor phase deposition processes are used to deposit a PZT layer onto a perovskite template layer on the substrate. The template layer is more readily deposited in a perovskite structure compared to PZT, and provides for nucleation and growth of the deposited PZT in perovskite form. The vapor phase deposition promotes the oriented structure of the resulting film. The structure is useful in a variety of devices, including surface acoustic wave devices.

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: The invention relates to use of a material containing a polymerizable monomer or oligomer, the material exhibiting desirable shrinkage compensation upon polymerization. The material contains an expansion agent having a cleaving moiety with the capacity to be cleaved or fragmented by a catalytic reaction, e.g., acid catalysis. The cleavage, by increasing the number of molecules in the material, causes expansion that compensates, at least in part, for shrinkage induced by polymerization of the monomer or oligomer. The expansion agent is capable of providing compensation such that no more than 0.4%, advantageously no more than 0.2%, volume shrinkage per molar concentration of polymerized monomer functional groups occurs, where such compensation is performed at relatively low temperatures of less than 40° C.

Abstract: A silica body useful for forming an optical fiber preform exhibits an ultimate strength of at least 20 MPa at 10 wt. % water loss. The body attains this strength, it is believed, by precipitation of silica at the contact sites of adjacent silica particles, thereby forming neck regions. The resultant network provides the strength to the gel body, such that the body is capable of being dried under more severe conditions than a gel body formed by previous sol-gel methods and is also more robust toward handling. The controlled precipitation is attained by inducing gelation and initiating drying at a pH of about 10.5 or higher, at which silica remains highly soluble. By gelling and drying at this pH level, the solubilized silica appears to precipitate in a controlled manner at the point of contact of adjacent silica particles, since such sites are the minimum free energy sites for precipitation.

Abstract: An improved process for holography is provided, in which the reference beam used for storage and readout has a correlated phase content. In particular, it was found that reference beams having random phase content limited the attainable storage density and the accuracy of readout of stored holograms due to uncontrolled fluctuations in the correlation selectivity. By contrast, a reference beam having correlated phase content provides accurate shift selectivity, the ability to tailor the reference beam spectrum to minimize crosstalk between neighboring holograms, and mitigation of limitations inherent in the holographic system or holographic medium. Improved storage density and readout accuracy are thereby attained.

Abstract: Photoacid generators advantageous for use in applications such as photoacid generators used in chemically amplified resists are disclosed. These compounds are based on an ortho nitro benzyl configuration employing an .alpha. substituent having high bulk, steric characteristics, and electron withdrawing ability. The enhanced efficacy is particularly found in compounds both having a suitable .alpha. substituent and a second ortho substituent with large electron withdrawing and steric effects.

Abstract: A method for fabricating an article, comprising the steps of grasping an outer surface of a first substrate with a first holder, whereby the outer surface of the first substrate is held to an inner surface of the first holder; grasping an outer surface of a second substrate with a second holder, whereby the outer surface of the second substrate is held to an inner surface of the second holder; arranging the inner surfaces of the first and second holders to face one another in a selected angular relationship; disposing an adherent on one or more surfaces selected from an inner surface of the first substrate and an inner of the second substrate; moving the first and second holders toward each other such that the inner surfaces of the first and second substrates contact the adherent; and at least partially curing the adherent while the inner surfaces of the first and second holders are in the selected angular relationship to form a multilayer article, wherein after removal of the first and second holders the at

Abstract: An article comprising an alloy exhibiting high magnetostriction in relatively low applied magnetic fields is provided, the alloy capable of being formed in a relatively easy manner and having desirable physical properties. The Co--Fe alloy of the invention exhibits a magnetostriction of at least 100.times.10.sup.-6 in a magnetic field less than 400 Oe, advantageously in a magnetic field less than 100 Oe. The alloy is formed by plastically deforming the alloy, e.g., by cold rolling, to a reduction in cross-sectional area of at least 50%, and then heat treating the alloy to induce recrystallization. This combination of plastic deformation and recrystallization was found to provide desirable grain growth and microstructure. The resultant alloy is useful in a variety of device components, including transducers, frequency filters, signal delay lines, and optical fiber grating devices.

Abstract: The invention provides a device with an improved tunable laser structure, the structure useful with surface emitting lasers and capable of exhibiting desirable latchability. The tunable laser of the invention contains a laser structure having a lower reflector, an active laser region, and an upper reflector. The upper reflector contains a non-moveable reflector portion located adjacent the active laser region and a moveable reflector portion located a spaced distance from the non-moveable reflector portion. A magnetic material is located either on a surface of the moveable reflector portion or on a surface in contact with the moveable reflector portion, and a programmable magnet is located near the magnetic material, the magnet capable of inducing controlled movement of the magnetic material. This movement in turn induces movement of the moveable reflector portion such that the spaced distance between the moveable reflector portion and the non-moveable reflector portion is capable of being adjusted.

Abstract: The invention provides an improved process for fabricating devices containing metallized magnetic ceramic material, such as inductors, transformers, and magnetic substrates. In particular, the unique vias utilized in the process of the invention allow fabrication of devices from multiple unfired ferrite layers with only a single via-coating step, thereby avoiding the need numerous punching steps. Moreover, there is no need for expanding the dimensions of the vias and thus no need for internal metallization. The invention therefore provides for green tape-type fabrication of devices such as inductors, transformers, and magnetic substrates in a manner faster, less complex, and more reliable than current methods. The invention also relates to use of an improved conductive material in such a process, the conductive material containing silver/palladium particles, ferrite particles, a cellulose-based or other organic binder, and a solvent.

Abstract: The invention provides a device containing a low .kappa., hydrogen-free a-C:F layer with good adhesion and thermal stability. It was found that the combination of desirable properties was attainable by a relatively easy process, as compared to processes that utilize gaseous sources, such as CVD. Specifically, the a-C:F layer is formed by sputter deposition, using only solid sources for the fluorine and carbon, and in the absence of any intentionally-added hydrogen-containing source. The sputtering is performed such that the layer contains 20 to 60 at. % fluorine, and also, advantageously, such that the a-C:F exhibits a bandgap of about 2.0 eV or greater. The a-C:F layer formed by the process of the invention exhibits a dielectric constant, at 1 MHz and room temperature, of 3.0 or less, advantageously 2.5 or less, along with being thermally stable up to at least 350.degree. C., advantageously 450.degree. C., and exhibiting a stress of about 100 MPa or less, in absolute value.