Abstract:
In accordance with the present invention, a field emission device is made by pre-activating ultra-fine diamond particles before applying them to the device substrate. This initial pre-activation increases manufacturing speed and reduces cost and reduces potential damage to the device substrate from exposure to high temperature hydrogen plasma.
Abstract:
The present invention provides a dielectric optical fiber cable which is capable of being remotely detected while buried. Specifically, this invention incorporates magnetic materials into a layer of epoxy to from a distinct layer within the sheath system of a communications cable. The magnetic particles generate a detection signal which is distinguishable from that generated by a solid metallic pipe and does not adversely affect the operation of existing components of the cable nor does the incorporation of the magnetic marker layer of the present invention unduly limit the speeds at which the overall cable can be manufactured.
Abstract:
Materials of composition La.sub.v X.sub.w M.sub.y Mn.sub.z O.sub.x, with x selected from Mg, Sc, Al, Zn, Cd, In and the rare earths that have an ionic radius smaller than that of La, with M selected from Ca, Sr, Ba and Pb, and with v, w, y, z and x in the ranges 0.45-0.85, 0.01-0.20, 0.20-0.45, 0.7-1.3 and 2.5-3.5, respectively, can have substantially improved magnetoresistance (MR) ratios, as compared to the corresponding X-free comparison material. In particular, the novel materials in polycrystalline (or non-epitaxial thin film) form can have relatively large MR ratios. For instance, polycrystalline La.sub.0.60 Y.sub.0.07 Ca.sub.0.33 MnO.sub.x had a peak MR ratio in excess of 10,000% (in absolute value) in a field of 6 T.
Abstract:
In accordance with the invention, a field emission device is made by disposing emitter material on an insulating substrate, applying a sacrificial film to the emitter material and forming over the sacrificial layer a conductive gate layer having a random distribution of apertures therein. In the preferred process, the gate is formed by applying masking particles to the sacrificial film, applying a conductive film over the masking particles and the sacrificial film and then removing the masking particles to reveal a random distribution of apertures. The sacrificial film is then removed. The apertures then extend to the emitter material. In a preferred embodiment, the sacrificial film contains dielectric spacer particles which remain after the film is removed to separate the emitter from the gate. The result is a novel and economical field emission device having numerous randomly distributed emission apertures which can be used to make low cost flat panel displays.
Abstract:
In accordance with the invention, a new type of microphone utilizes a magnetoresistive sensing element. Specifically, acoustical energy causes vibrations between a magnetoresistive element and a magnet, producing a variation in the resistance which can be used to convert an acoustical signal into a corresponding electrical signal.
Abstract:
The disclosed method of shaping a diamond body, typically a polycrystalline diamond (PCD) wafer or film, involves forming a, typically patterned, layer of an "etch-retarding" material on a surface of the diamond body, followed by etching with an appropriate etchant (e.g., molten Ce). Etch-retarding materials are selected from the materials that have low (typically less than 5%) mutual solubility with the etchant at the processing temperature, and that essentially do not form an intermetallic compound with the etchant at the processing temperature. Among etch-retarding materials are Ag, Ca, Mg, Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf, B, P, and alloys thereof, as well as ceramics such as oxides, nitrides, carbides and borides, e.g., WO.sub.2, TiO.sub.2, MoC, TiC, Fe.sub.4 N, ZrN, MoN, CeB.sub.6 and Mo.sub.2 B. The etch-retarding material typically will be of appropriately chosen, non-uniform thickness, with the thickness at a given point depending on the amount of diamond material that is to be removed at that point. The disclosed method has wide applicability, e.g., for correcting thickness variations or curvature of PCD films.
Abstract:
In accordance with the invention, an image is formed by applying a local magnetic field to selected regions of a magnetic composite medium comprising columns of magnetic particles distributed in a matrix medium. The particles are "hard" or "semi-hard" magnetic materials in order to retain the latent image as residual magnetism, and the image is developed by exposure to magnetic fluid or powders. The image can be erased by exposure to an AC demagnetizing field or a DC sweep magnet. Preferred apparatus for making such images comprises a sheet of such composite material having a pair of major surfaces with columns of magnetic particles oriented between the surfaces. A local magnetic field, such as a magnetic pen, can be used to write a latent magnetic image on one of the major surfaces. The magnetic columns present the latent image for development at either major surface. In preferred apparatus, one major surface is adapted for magnetic image writing and the other major surface is positioned in sealed relationship with a chamber for exposing the image to magnetic development material. In this arrangement the columns provide a high resolution image on the second surface despite the thickness of the medium between the write and development surfaces.
Abstract:
Electrical interconnections are made by means of a layer or sheet medium comprising chains of magnetically aligned, electrically conducting particles in a nonconducting matrix material. End particles of chains protrude from a surface of the medium, thereby enhancing electrical contact properties of the medium. The medium can be used for temporary as well as permanent connections; in the latter case the use of a nonconductive adhesive material is convenient for physical attachment to contacts on both sides of the medium.
Abstract:
Superconductive oxide bodies such as wires, ribbons, rods, and other bulk bodies can be fabricated by a process that comprises melting precursor material, cooling at least of the melt such that a solid body of a desired shape results, and heat treating the solid body in an oxygen-containing atmosphere. The precursor material exemplarily is in the form of pressed superconductive oxide powder. The re-solidified superconductive material is relatively dense, typically textured, with relatively large grain size, and has improved properties, e.g., higher critical current density. An exemplary technique for melting of the precursor material is zone melting.
Abstract:
Magnetically actuated devices such as, e.g., switches and synchronizers typically comprise a magnetically semihard component having a square B-H hysteresis loop and high remanent induction. Among alloys having such properties are Co-Fe-V, Co-Fe-Nb, and Co-Fe-Ni-Al-Ti alloys which, however, contain undesirably large amounts of cobalt.According to the invention, devices are equipped with a magnetically semihard, high-remanence Fe-Mn alloy which contains Mn in a preferred amount in the range of 3-25 weight percent whose remanence B.sub.r (gauss) typically is greater than or equal to 20,000-500.times. (weight percent Mn), and whose squareness B.sub.r /B.sub.s typically is greater than 0.95.Magnets made from alloys of the invention may be shaped, e.g., by cold drawing, rolling, bending, or flattening and may be used in devices such as, e.g., electrical contact switches, hysteresis motors, and other magnetically actuated devices.Preparation of alloys of the invention may be by a treatment of initial deformation, aging, deformation, and final aging.