Abstract: The accelerometric sensor is of the type comprising a fixed mass, a mobile mass and two flectional vibrating beams each having ends that are linked to the masses. According to the invention, the masses and the beams consist of one single piece machined in a same plate of material of uniform thickness, e.g. in a piezoelectric material such as quartz. The single piece preferably comprises two second beams each having ends that are integral with the masses and placed on both sides of the vibratory beams. The flexural stiffness of the second beams is higher than that of the vibrating beams.

Abstract: Both a system and method are provided for detecting and locating a leak in the housing of the steam turbine components of an electric generator of the type that are connected to a vacuum pump that generates a negative pressure to remove air from the steam system, comprising a source of tracer gas for releasing a quantity of gas at potential leak locations on the exterior of the housings, a saturatable tracer gas detector having an inlet port in fluid communication with an outlet of the vacuum pump for detecting a flow of tracer gas associated with a selected minimum leak condition and for generating an electrical signal corresponding to this condition, an electrically controllable butterfly valve located upstream of the inlet port of the tracer gas detector for regulating the amount of tracer gas that flows into the detector, and a control assembly including a microprocessor that is electrically connected to both the tracer gas detector and to the valve for preventing a saturating flow of tracer gas from ente

Abstract: An NMR system acquires a series of spin-echo signals during a scan and these are used to reconstruct an image. The spin-echo signals are partially acquired by locating the data acquisition window asymmetrically with respect to the echo peak. A homodyne reconstruction is employed to fill in the missing data during the image reconstruction.

Abstract: A signal function S(t.sub.1, t.sub.2) is obtained from a plurality of coherence transfer pathways in a single acquisition by preparing a molecular system in a coherent non-equilibrium state, and alternately and sequentially detecting signals at individual sampling points, in t.sub.2, from the plurality of coherence transfer pathways by using gradient refocusing of a new pathway after siganl detection at a sampling point in another pathway. The gradient encoding and refocusing of coherence pathways can use inhomogeneous rf-pulses (B.sub.1 gradients) or B.sub.0 field gradients. The coherence transfer pathways can be sequentially selected in an arbitrary order.

Abstract: An NMR imaging system executes a series of fast spin echo pulse sequences to acquire data for a plurality of images having different T.sub.2 -weighted contrast. Only low-order phase encoding data is acquired separately for each image and the scan time is reduced substantially by using common high-order phase encoding data for all the images.

Abstract: A saddle coil for multiple tuned response is realized by a segmented sequence of first LC elements each tuned to exhibit a low impedance at .omega..sub.1 and a second set of LC elements, each tuned to exhibit a low impedance at .omega..sub.2, at least some of said first set of LC elements having one of said second LC elements in parallel therewith.

Abstract: An apparatus for measuring stress of viscoelastic material in which a rotational die and a torque detecting die are provided, an outer cylindrical die is provided around the torque detecting die, the diameter of the rotational die is arranged to be larger than the diameter of the outer cylindrical die, and the surface forming one part of a sample chamber has such configuration that a slipping of the sample contained in the sample chamber is prevented, so that a shearing speed having no disorder can be given to the sample mounted all over a surface, forming the sample chamber, of the torque detecting die.

Abstract: The distance between a semiconductor wafer and a bake/chill plate is determined by a feed back system using a flow meter. The wafer forms part of the feed back system by limiting the flow of air or gas between the wafer and bake/chill plate, the distance between the wafer and bake/chill plate determining the amount of flow of air or gas through the flow meter.

Abstract: A double-tuned NMR sample excitation coil has a first end connected through a first balancing inductor to ground and a second end connected through a second balancing inductor to a low-frequency (LF) capacitor tuning and matching network. Two two balancing inductors have inductance less than 50% but greater than 10% that of the excitation coil. Each balancing coil is tuned by a capacitor network to an independent resonant frequency when disconnected from the sample coil that is less than 95% but greater than 60% of the final high frequency (HF) resonance. Moreover, both such independent resonant frequencies are equal within 10%. Broadband operation is possible under a variety of temperatures and the circuit works with high-speed sample spinners.

Abstract: A dielectric resonator is used in a magnetic resonance examination apparatus comprising a magnet system (31, 32) for generating a steady magnetic field in an examination space (2), a transmitter device (12, 13, 18, 28) for generating an RF field to be superposed on the steady magnetic field in an object (30) to be examined, a device for producing a resonance step-up of the RF field active in the object (30) to be examined, and a device for detecting magnetic resonance signals generated in the object (30) to be examined. Stronger B.sub.1 fields are created by at least one dielectric resonator (1, 5, 10, 16, 17, 20, 21) which neighbors the object (24) to be examined and which comprises a dielectric having a relative dielectric constant .epsilon..sub.

Abstract: A method for calibrating a differential odometer in a vehicle (10) having a pair of wheels (14, 16) and a pair of associated wheel sensors (18, 24) which generate output pulses as their associated wheels rotate. The method includes driving the vehicle (10) around a path (12) in a first direction (counterclockwise or clockwise), measuring the vehicle's heading change (preferably 360 degrees), and counting the number of pulses generated by each wheel sensor (18, 24) while the path is traversed. Then the vehicle is driven around the same, or a different, path in the opposite direction, again measuring the vehicle's heading change, and counting the number of pulses generated by each wheel sensor (18, 24). The pulse counts, the measured heading changes, and the known distance between the vehicle's wheels, are used to calculate the distance traveled by each wheel per output pulse from its associated wheel sensor.

Abstract: A surface resonator for use in a magnetic resonance imaging apparatus having a transversal fundamental magnetic field is composed of two sub-systems, each generating a magnetic field with the magnetic fields being perpendicular relative to each other. Each sub-system contains two current loops, both of which enclose the magnetic field allocated to them in the same plane. A circularly polarizing surface resonator is thus obtained for the transversal fundamental magnetic field.

Abstract: There is disclosed a method for determining the proper sealing of a hermetically sealed package. The method consists of the steps of providing a pressure source for effecting a movement of air mass, providing an enclosable vacuum chamber suitable for accommodating a hermetically sealed package therein being enclosable in sealing tight engagement. An air flow path is provided from the vacuum chamber to the pressure source, the air flow path having a valve interposed to isolate the vacuum chamber from the pressure source. The air flow path is provided with a mass flow transducer and a pressure differential measuring device. A hermetically sealed package is placed in the vacuum chamber and by activating the isolating valve to connect the vacuum chamber to the source of pressure, a flow of gas is effected through the air flow path activating the pressure differential measuring device to determine the rate of mass flow of gas through the mass flow transducer as a function of time.

Abstract: An image data set acquired by an NMR system using an echo-planar pulse sequence is corrected for systemic errors. Errors are measured by acquiring a reference data set using the same echo-planar pulse sequence without phase encoding, and the measured errors are employed to correct phase errors in the image data set.

Abstract: Improved apparatus and method are provided for locating and mapping sediment in a container, which is at least partially filled with liquid. A sonar transducer is mounted with the container for emitting acoustic energy into the liquid and for receiving reflected acoustic energy. The sonar transducer is rotatable about mutually perpendicular first and second axes to provide a dual-axis capability. The transducer is controlled to emit discrete acoustic signals and receive reflected acoustic signals along discrete scanning axes at each rotational position in a predetermined sequence of rotational positions. The distance between the transducer and a corresponding point of reflection along each scanning axis is compared to a predetermined reference distance along the corresponding scanning axis. The reference distance represents the distance between the transducer and an inner surface of the container along the corresponding scanning axis.

Abstract: A circularly polarizing RF antenna suitable for use in an MRI apparatus for obtaining tomograms of an examination subject includes two antenna systems, each having a winding, having two lateral legs and a middle leg, and a return path which form a resonant circuit in combination with one or more resonant capacitors. The middle legs of the two antenna systems are disposed so that they cross one another. One or more decoupling capacitors are provided between the two antenna systems. A circularly polarizing antenna for a magnetic resonance imaging system is thus obtained having a magnetic field vector in the imaging region which rotates in planes parallel to the pole surfaces of a C-shaped magnet which generates the fundamental magnetic field in the magnetic resonance imaging apparatus.

Abstract: An automatic viscosity measuring device which measures sample levels, automatically fills a sample to a marked line by vacuum pressure, automatically counts the time for the sample to fall by a sensor in the upper and lower marked lines, finds intrinsic viscosity by concentration and then measures the degree of error from relative viscosity in the case of the Ostwald's viscosimeter, which automatically measures the viscosity of a high molecular material.

Abstract: A transmission antenna for a nuclear magnetic resonance apparatus has a capacitor connected in parallel with it via at least one PIN diode, and a reception antenna for the apparatus has a capacitor connected directly in parallel with it and an inductor connected in parallel with it via a PIN diode. The PIN diodes are connected to a control voltage in a series circuit. Given a first direction of the control voltage, the PIN diodes are conductive, so that the transmission antenna is tuned to the nuclear magnetic resonant frequency due to cut-in of the capacitor and the reception antenna is detuned to the cut-in of the inductor. Given a second direction of the control voltage, the reception antenna is tuned to the nuclear magnetic resonant frequency and the transmission antenna is detuned with respect to the nuclear magnetic resonant frequency. An unwanted, local super-elevation of the RF power cannot occur with this antenna.

Abstract: A circularly polarizing RF antenna suitable for use in a magnetiic resonance imaging tomography apparatus has four current loops, each formed by two U-shaped conductors with the ends of the lateral legs of the U-shaped conductors disposed opposite to each other in mirror-symmetric fashion, and the ends of the lateral legs being bridged by a resonant capacitor. The current loops are arranged on a carrier which forms a portion of a hollow cylinder, and which is divided in an axial direction between two of the current loops, so that at least one of the current loops is removable without electrical contacts. A divisible RF antenna is thus achieved into which a head or a knee joint can be easily introduced for imaging.

Abstract: The apparatus of the invention comprises a measurement chamber fed with gas under pressure by a feed nozzle, a measurement chamber having an outlet nozzle spaced apart from the feed nozzle and including a pressure take-off point disposed between the feed nozzle and the outlet nozzle. According to the invention, a separating partition extends inside the measurement chamber overlying the pressure take-off point and co-operates with the wall of the measurement chamber to determine a volume which is closed in airtight manner at its outlet nozzle end and which is open at its inlet nozzle end in the vicinity of the inlet nozzle.