Abstract: A magnetic sensor is constructed to be capable of detecting the change of tunnel current due to co-tunneling effect at a high S/N ratio by using a tunneling magneto-resistive element having a first magnetic layer of a soft magnetic material formed on a flat substrate, first and second tunnel barrier layers formed on the first magnetic layer, magnetic particles of a ferromagnetic material provided between the first and second tunnel barrier layers, and a second magnetic layer of a soft magnetic material formed on the second tunnel barrier layer so as to create tunneling junctions.

Abstract: This patent application is to use dynamic electromagnetic wave reflection and refraction methods for prospecting for oil directly. The available geophysical methods including the most used seismic reflection method are all prospecting for oil indirectly, viz., aiming at finding the geological structures and stratigraphic traps, etc. The high contrasts of electric permittivity between oil cord the surrounding geological formations of rocks including gas, water (fresh and salt), on the other hand, make it possible to use the dynamic electromagnetic wave reflection and refraction methods for prospecting for deep seated oil directly.

Abstract: A method for manufacturing a GMR bridge detector as well as the bridge detector itself in which magnetoresistive resistors are interconnected in the form of a bridge to detect a magnetic field. The resistors consist of a material that exhibits the giant magnetoresistive ratio (GMR) effect. The magnetoresistive sensitivity of the individual resistors is produced through annealing. The annealing of the resistors takes place through selective feeding of a current that is sufficient for reaching the temperature required for annealing into the bridge connections. Depending on the wiring of the bridge connections, the resistors are provided with the property necessary for the GMR effect either singly or in pairs. As the material for the resistors, in particular, a material of the class of discontinuous multilayer materials, particularly NiFe/Ag, is used in which the GMR property is produced through single annealing at a specific temperature.

Abstract: An eddy current inspection probe for inspecting a preselected surface at least partially defining an opening in a component. The eddy current inspection probe includes a core moveable between a retracted position and an expanded position in which the probe is sized and shaped for at least partially filling the opening and contacting the preselected surface for inspecting the surface. The probe includes a compliant covering positioned over the exterior surface of the core and an eddy current array positioned over the outer face of the covering. Further, the probe includes an element positioned between an exterior surface of the core and an inner face of the covering having a coefficient of friction selected to permit the inner face of the covering to move tangentially with respect to the exterior surface of the core as the core is moved from the retracted position to the expanded position to ensure intimate contact between probe and the preselected surface of the component being inspected.

Abstract: An arrangement for determining the rotational behavior of a rotating body or encoder (3) includes a sensor module (1) which comprises a sensor element (2; 2.1 to 2.4), a controllable power source (4) supplying a load-independent current representative of the rotational behavior, a modulator (5) that controls the power source (4) as a function of signals of the sensor element (2; 2.1 to 2.4) and of signals supplied by an external signal source through an additional port (K5), and an evaluating circuit (9). The sensor module (1) is magnetically coupled to the encoder (3). The output signal of the sensor module (1) is a signal, representative of the rotational behavior, with a superimposed status signal and/or additional signal.

Abstract: A magnetic device mounts on a flat spoke of a wheel. This magnetic device can comprise a magnet and a housing. The housing is coupled to the magnet, and has a spoke-receiving recess with a non-circular cross section, and at least one detent. The detent extends from the housing into the spoke-receiving recess to secure a flat spoke within the spoke-receiving recess via a snap-fit. The magnetic device communicates with a sensing device, which is adapted to be coupled to a portion of the bicycle that is adjacent to a wheel of the bicycle. A display unit, adapted to be mounted on handlebars of the bicycle, displays the speed information obtained from the sensing device. In a second embodiment, the housing is made of a more elastic material, and the detents become optional. In a third embodiment, the spoke-receiving recess of the housing has a projection that engages a concavity form in the connecting portion of the spoke.

Abstract: Good magnetic, wear, and corrosion properties are required of a pinned synthetic anti-ferromagnet used in a top spin valve magnetoresistive sensor for reading magnetic media. The pinned synthetic anti-ferromagnet includes a synthetic anti-ferromagnet. An oxidation protection layer is deposited on the synthetic anti-ferromagnet. A nickel oxide layer for pinning the synthetic anti-ferromagnet is deposited on the oxidation layer.

Abstract: There is provided a highly reliable rotation sensor which is capable of accurate detection of a rotation state. The rotation sensor comprises: a rotor rotating together with a rotation portion of a detection side; a first supporting member for rotatably supporting the rotor; and a detecting member secured to the first supporting member for detecting a rotation state of the rotor. The first supporting member is supported movably in both directions, that is, an X direction orthogonal to the direction of the rotating shaft of the rotor and a Y direction which is orthogonal to the direction of the rotating shaft of the rotor and orthogonal to the X direction.

Abstract: A rolling bearing unit for the hub of a vehicle wheel has an outer rotating race (10), a radially inner stationary race (11), a sealing device (16) between the races (10, 11), and a device for measuring the rotating speed of the outer race (10). The measuring device has an encoder wheel (13) in the form of a radially oriented annular disc of magnetised plastic or rubber material.

Abstract: A position sensor comprises a rotor and shaft connected to a housing for rotation about a rotational axis. A sensor base is fixedly connected to the housing and is spaced from the rotor. A Hall-effect sensor is fixedly connected to the sensor base, and a magnet is connected to the rotor for rotational movement therewith. The magnet has an upper polarized surface that faces the magnetic sensor to thereby generate a magnetic field coincident with the magnetic sensor. The polarized surface is semi-parabolic in shape to form a variable gap between the magnetic sensor and the polarized surface as the shaft and rotor are turned about the rotational axis to thereby vary the strength of the magnetic field at the magnetic sensor. With this arrangement, the strength of the magnetic field sensed by the magnetic sensor is indicative of the amount of relative movement between the rotor and the housing.

Abstract: In an angle-based crankshaft position sensing system, an electrical circuit is provided for also sensing the direction of rotation of the crankshaft. A slotted target wheel is coupled to the crankshaft and a single dual-element MR sensor is juxtaposed with the target wheel. The elements generate respective detection signals when a slot passes by the elements, with the position of the slot being indicated as being directly under the sensor at the point in time when the detection signals intersect each other. Also, square waves are generated for each detection signal, and when the magnitude of the second square wave is non-zero when the falling edge of the first square wave occurs, a clockwise rotation is indicated. On the other hand, if the magnitude of the second square wave is zero when the falling edge of the first square wave occurs, a counterclockwise rotation is indicated.

Abstract: When prospecting for geological formations, a feeding electrode 2 is grounded in the centre of a circle formed by uniformly grounded feeding electrodes 3. The feeding electrodes 3 are connected by lengths of supply lines 4 to current generators 1 via regulators 5. A first stage of investigations involves a preliminary sounding. Current pulses are applied from the generators 1 to the lengths of supply lines 4 which are connected to diametrically opposite feeding electrodes 3. A current pulse period is synchronized with a reference signal received by a receiver 7 from the global radio navigation system. Upon turning the current off, a signal of a field magnetic component transient is measured by a meter 8 that is coupled to a magnetic component sensor 9.

Abstract: A device for measuring the rotation of a rotating element which contains a magnetic encoder which turns with the rotating element and a sensor integrated with a support which is immobilized in terms of rotation. The magnetic encoder is maintained in close proximity to the sensor by the application of magnetic attraction forces between the magnetic encoder and the support, which is produced, at least partially, out of magnetic material.

Abstract: The present invention provides a method for the direct measurement and quantification of the material volume loss on the surface of a substrate and thus provides an accurate depiction of the surface profile of the surface. The method of the invention comprises inducing eddy currents in a test substrate, measuring the magnitude of the eddy current produced within the substrate at a plurality of locations on the surface of the substrate, and converting the measured eddy current magnitudes at the locations to corresponding volume losses on the test surface using the eddy current magnitude measurements of a reference substrate having defects of predetermined volume loss. Typically, the measurements of the eddy current magnitude on the test surface are converted to actual volume losses by multiplying the measured eddy current magnitude for a sector of the test substrate by the area of the sector and a calibration factor (Cf) representing the volume per unit area eddy current magnitude.

Abstract: In an apparatus for determining the contents of a battery or accumulator (10), the inductive coupling provided by the battery or accumulator (10) between an excitation coil (20) and a sense coil (30) is measured. To improve the selectivity of the apparatus magnets (41, 42) are provided that generate a quasi-static magnetic field during a measurement. The quasi-static magnetic field saturates the iron in an ornamental jacket of the battery or accumulator (10) so that the inductive coupling between excitation coil (20) and sense coil (30) is almost completely determined by the interior of the battery or accumulator (10). The inductive coupling at different frequencies, with and without the quasi-static magnetic field, yields a reliable identification. The excitation coil (20) can be energised by a current source (21, 22, 23) generating an alternating current with constant amplitude.

Abstract: The present invention discloses 10 discloses an eddy current probe assembly having unique types and arrangements of coils 14, 16, 18 therein. This type and arrangement of coils allows for a more accurate determination of tube 20 anomalies. A first pair of coils 14 are provided which comprise a pair of coils 14A, 14B oriented 45 degrees apart wherein each pair of coils comprises an additional pair of coils 14G, 14H which are oriented 90 degrees apart. A second pair of coils 16 are provided which are about 0.060 inches apart. A third pair of coils 18 are provided having a larger coil 18A and a smaller coil 18B. An extension wand 22 with cable connectors 26 are provided for connection to suitable probe actuation and control means.

Abstract: A magnetic field sensor comprising a layered structure (3) E/Fo/S/F, in which: E is an exchange-biasing layer, comprising nickel oxide; Fo is a ferromagnetic layer with a fixed magnetization, comprising cobalt; S is a spacer layer; Ff is a ferromagnetic layer with a free magnetization, whereby the material of the layer Ff has a magnetostriction constant of at most 1.5×10−6 and a crystal anisotropy of at most 1.3 J/m3. Such a structure (3) demonstrates a relatively high magneto-resistance ratio (of the order of 15%), and yet a relatively low coercivity (of the order of 0.2 kA/m). Examples of suitable materials for use in the layer Ff include Ni66Fe16Co18 and Ni72Fe21Co7.

Abstract: A cased well in the earth is electrically energized with A.C. current. Voltages are measured from three voltage measurement electrodes in electrical contact with the interior of the casing while the casing is electrically energized. In a measurement mode, A.C. current is conducted from a first current carrying electrode within the cased well to a remote second current carrying electrode located on the surface of the earth. In a calibration mode, current is passed from the first current carrying electrode to a third current carrying electrode located vertically at a different position within the cased well, where the three voltage measurement electrodes are located vertically in between the first and third current carrying electrodes. Voltages along the casing and resistances along the casing are measured to determine wall thickness and the location of any casing collars present so as to electrically inspect the casing.

Abstract: A rolling bearing unit has a rotational speed detection device which is comprised of a sensor having a yoke, a pair of permanent magnets and coil, and a tone wheal which is made by press-forming a magnetic metal plate so as to comprise a cylindrical support base secured onto an end portion of the bearing unit, a ring-shaped first detecting part which is bent radially outward from the inner rim of the cylindrical support base, and a cylindrical shaped second detecting part which extends axially from the outer peripheral rim of the first detecting part the first and second detecting parts having a ferro-magnetic first portion and a non-magnetic second portion, and the yoke having opposite ends to be faced to the first and second portions, and the permanent magnets being faced to each other so that magnetic fluxes flow alternatively through the yoke corresponding the rotation of the tone wheel.

Abstract: A method of varying the capacity of a multi-platter hard disk drive, having a plurality of head/disk combinations, during a manufacturing process includes scanning the overall disk surfaces to detect defects. If the number of defects detected on a disk surface exceeds a design specification number, the head/disk combination having the disk surface is determined to be defective. Then, the use of the defective head/disk combination is avoided, to thereby vary the capacity of the hard disk drive.