Abstract: An accelerometer includes a cantilevered pieozelectric beam mounted to a surface inside a fluid filled chassis with a proof mass attached to the beam's free end. Surface skimming bulk wave delay lines are mounted on opposing major surfaces of the beam and are responsive to strain induced therein by acceleration of the proof mass.

Abstract: A tool for use downhole has means (18, 19, 20, 44) for engaging materials surrounding the hole. The engagement means (18, 19, 20, 44) are operated by hydraulic pressure controlled by a hydraulic circuit (10). A hydraulic power module (11) is provided for varying hydraulic pressure in the hydraulic circuit (10) to effect movement of the engagement means (18, 19, 20, 44). In case of failure, a dumping assembly (17) is provided to allow relief of hydraulic pressure in the circuit (10). The dumping assembly (17) includes a dump chamber (62) of variable volume, a dump valve (60) and a non-return valve (61); the hydraulic circuit being capable of being re-set downhole after dumping, there being no need to bring the tool to the surface.

Abstract: A method and apparatus are provided for permitting an instrumentation package to be repeatedly locked and unlocked at any number of desired depths inside a subsurface production tube for the determination of the shut-in physical conditions at those depths. An instrumentation package is located below a tube packoff tool. The instrumentation package and tube packoff tool combination are lowered into the tube. At the desired depth, a longitudinal force is exerted on the tube packoff tool, causing the tube packoff tool to wedge against the inside of the tube, locking the tube packoff tool at that depth, and creating a seal which isolates the instrumentation package below. The instrumentation package then begins its determination of the shut-in physical conditions inside the tube at that depth and transmits the acquired data to a surface recording and processing facility.

Abstract: The magnetic apparatus of a nuclear spin tomography system contains several magnet coils which are surrounded by an approximately hollow-cylindrical shielding device of ferromagnetic material. At each end face, this shielding device has a disc-shaped plate with a central opening. Four beam-like shielding elements of identical design having triangular or trapezoidal cross section, arranged distributed in the circumferential direction regularly on a common cylinder surface, extend between these plates at the end faces. With this magnetic apparatus, field distortions caused in the useful volume by the four beam-like shielding elements are substantially reduced.

Abstract: An angular velocity sensor of the tuning-fork gyro type includes a first oscillating element including a drive element and a detection element and a second oscillating element including a monitor element and a detection element. A single resilient member couples the oscillating elements to a base support. Drive power is supplied only to the drive element which oscillates and causes the second oscillating element to oscillate. A signal produced by the monitor element is used to adjust the drive power and is combined with the signal produced by the detection elements to produce an output signal indicative of angular velocity.

Abstract: An NMR imaging apparatus and method for direct Fourier imaging. This apparatus includes a static magnetic field generator, gradient magnetic field generators, high-frequency magnetic field generator, signal detecting detector for detecting a nuclear magnetic resonance signal from a body to be inspected, a computer for performing an arithmetic operation for the detected signal to obtain the nuclear magnetic resonance intensity distribution in the to-be-inspected body from measured values of the nuclear magnetic resonance intensity distribution at various points on a rectangular coordinate system in the Fourier space, and memories used for correction.

Abstract: Improved nuclei excitation for NMR applications is provided by employing a sequence of RF pulses for exciting the nuclei. Non-linearities in pulse excitation are compensated by applying at least one additional RF pulse thereby improving slice definition and/or phase characteristics. In one application, one or more initial RF pulses establish an intermediate state for the nuclei from which the nuclei can be tilted to a final desired magnetic moment state by the application of a single RF pulse. The order of applying the magnetic pulses can be reversed when the flip/angle is 180 degrees.

Abstract: An antenna device for exciting a magnetic high-frequency field and/or for receiving corresponding high-frequency signals in a nuclear spin tomography apparatus contains a tubular antenna part which is designed to largely pass low frequencies, for magnetic gradient fields, consists of electrically highly conductive nonmagnetic material and has means for connecting to an external energy feeding or receiving device. In order to permit a simple design for this antenna device, only the tubular antenna part is provided as a circular waveguide for exciting or receiving the high frequency field. The circular waveguide is provided at least in the region of the cross-sectional plane extending through the center of its axial dimension with a system of coupling elements for coupling in or out the corresponding high-frequency power. In addition, further coupling systems may be provided in at least two cross-sectional planes symmetrical to the central cross-sectional plane.

Abstract: A method for reversing residual transverse magnetization due to spatial encoding magnetic field gradient pulses, used in magnetic resonance imaging to encode spatial information, employs a reversing gradient pulse applied in the same direction as the encoding gradient pulse following the observation of the spin-echo signal. The encoding gradient pulse is applied following the 180.degree. RF pulse to avoid the effects of imperfections associated therewith. In one embodiment, the amplitudes of the encoding and reversing gradient pulses are selected to be approximately the negatives of each other so as to substantially cancel the residual magnetization. In another embodiment, the amplitude of the reversing gradient pulse is selected such that the algebraic sum thereof with the corresponding amplitude of the encoding gradient pulse is a constant. In this case, the residual magnetization is not necessarily cancelled, but rather, is left in the same state after each view of the pulse sequence.

Abstract: An NMR imaging apparatus which generates NMR signals cleared of foreign noises by adding a noise detecting coil, for detecting mainly the foreign noises, to an intrinsic detecting coil for detecting the NMR signals and by producing a difference from the outputs of the two detecting coils. As a result, the foreign noises can be eliminated simply and effectively without requiring expensive shielded rooms.

Abstract: An accelerometer sensor comprising a flat pendular structure having a fixed part and a flat test body suspended from the fixed part by two parallel blades flexible in the plane of said test body, so as to be able to move in translation along a sensitive axis. Said test body extends at least partially into the space between said two flexible blades.

Abstract: A device and method are shown for detecting fluid flow in a well bore. A downhole device suspended from a cable drum is used to sense the movement of fluid in the borehole. The movement of the downhole device is then synchronized with the fluid movement and the speed and direction of movement of the cable is measured at the well surface to provide a direct indication of the direction and rate of the fluid flow.

Abstract: The static magnetic fields of an NMR imaging apparatus should be maintained constant in intensity in order to obtain satisfactory NMR images. Coils used to generate the static magnetic fields, and the supporting frames therefor, are subject to heat expansion due to changes in the temperature, which causes fluctuations in the intensity of the generated static magnetic fields. In the invention, the temperatures of the coils, frames, atmosphere and cooling water, and the amount of cooling water, are detected, and the energizing current for the static magnetic field coils is selectively controlled, based on the detected quantities, to thereby maintain constant the intensity of the generated static magnetic fields.

Abstract: A piezoelectric pick-up device for an internal combustion engine is disclosed, which comprises a metal case mounted on an internal combustion engine cylinder wall or the like, a mounting metal rod projecting from the inner bottom surface of the metal case into the interior thereof, a piezoelectric element and a weight disposed in the case interior and fitted on the mounting rod, the piezoelectric element being electrically coupled to the metal case, a cap-like cover fittedly covering the weight or the entirety of the piezoelectric element and the weight, and a molding material filling the case interior. The cap-like cover is made of an elastic material or a hard material.

Abstract: A vibration and acoustic wave detecting device employing a piezoelectric element has a construction such that a piezoelectric element comprises a first surface electrode disposed on a first surface of the piezoelectric element and having a first output terminal of the detecting device, a second surface electrode opposite to the first surface thereof, a side electrode disposed to surround a side surface of the detecting device and having portions respectively extending over the first and second surfaces, the three electrodes being disposed separately from each other, and a resistor disposed on the piezoelectric element to extend across the first surface electrode and the side electrode and to be connected therewith electrically, and the piezoelectric element further comprises a conductive member which is attached to the piezoelectric element to be in contact with the second surface electrode and the side electrode and hence to provide electrical connection between both electrodes.

Abstract: An NMR diagnostic apparatus capable of obtaining tomographic images in any direction and in any portion of the patient. A magnetic device applies a static magnetic field along a longitudinal axis of the patient. A first coil device is arranged along this longitudinal axis and applies a first gradient magnetic field in conjunction with the static magnetic field so as to define a slice in the patient which is to be examined. The first coil device also applies at least one second gradient magnetic field which defines a projection angle from which NMR signals are obtained. A probe head coil device applies RF pulses to excite nuclei in the slice and to detect the NMR signals emanating from the slice. A second coil device is arranged along the longitudinal axis and applies to the slice a shifting magnetic field which shifts a magnetically-zero plane of the first gradient magnetic field in a direction perpendicular to the magnetically-zero plane.

Abstract: Nucleons which are chemically bound to oil and water in geological formations possess magnetic moments which align in the earth's magnetic field causing the natural nuclear paramagnetism of the formation. An A.C. magnetic field at the Larmor frequency is repetititively applied to the formation adjacent to a borehole resulting in a repetitive excitation-relaxation process of the nucleons present within an "excitation zone" which results in an amplitude modulation of the paramagnetism within this zone. This physical process results in an amplitude modulation of the earth's magnetic field in the vicinity of the excitation zone of the formation and is called the Paramagnetic Logging Effect (PLE). The PLE may be measured with logging tools in open holes and within cased well bores.

Abstract: Arrangements for selectively exciting sections of bodies being imaged in NMR systems wherein the rotating magnetic fields are shaped with envelopes defined by the sum of a sinc function and a cosine function.

Abstract: A directional accelerometer and a process for the microlithographic fabrication of such an accelerometer. The accelerometer includes a substrate having at least one recess to define at least one beam in the substrate. One of the ends of the beam is integrally formed with the remainder of the substrate. The beam, which is oriented in the first direction, is deformable into the recess in a second direction only, parallel to the substrate surface and perpendicular to the first direction. The second direction corresponds to the acceleration component to be measured. Electrical connections and contacts are formed in the substrate for the device measuring the deformations of the beam. These measurements make it possible to determine the acceleration components.

Abstract: A gyro apparatus is disclosed which includes a base table, a detecting piezoelectric element attached at its one end to the base table such that its longitudinal direction, is perpendicular to the surface of the base table, a tuning fork having a vibration surface parallel to the surface of the base table and disposed such that its axis is parallel to the surface of the detecting piezoelectric element, and an L-shaped attaching portion attached to a base portion of the tuning fork such that its one leg portion is parallel to said surface of the base table and extended in the direction to vibration mass portions of the tuning fork, wherein the one leg portion is attached with the other end of the detecting piezoelectric element.