Showing papers on "Magneto published in 2004"

Magneto-mechanical apparatus

Abstract: A magnetic field based mechanical apparatus is disclosed. The apparatus is based on coupled attracting or opposing magnets in conjunction with the insertion or removal of a magnetic field modifier. In the preferred embodiment, two repelling magnets (11, 12) are drawn together with the insertion of a magnetic field modifier (13). The field modifier may be another magnet having an opposing pole. Removal of the field modifier returns the forces to their original states. This oscillating motion may be driven with a low energy and/or small power supply. The resulting motion of the opposing magnets can drive mechanical system such as a linear, gear, ratchet, or reciprocating drive.

Relaxation effects on thermal shock problems in an elastic half-space of generalized magneto-thermo elastic waves

Abstract: The propagation of electromagneto-thermo-elastic disturbances produced by thermal shock based on Lord-Shulman (L-S), Green-Lindsay (G-L) and classical dynamical coupled (CD) theories in a perfectly conducting half-space are studied. There acts an initial magnetic field parallel to the plane boundary of the half-space. The normal mode analysis is used to obtain the exact expressions for the considered variables. The distributions of the considered variables are represented graphically for each case. A comparison is made with the results predicted by the coupled theory. It is found that the magnetic field has decreasing effect.

Integrated 1/f noise removal method for a magneto-resistive nano-particle sensor

Abstract: The present invention provides an integrated circuit and a method for noise removal in a magnetic nano-particle sensor device. The method of the present invention comprises the steps of sending a conductor current through a conductor to generate a first horizontal magnetic field component at the location of a magneto-resistive sensor. In a further step the optimal operation point of the magneto-resistive sensor is determined by minimising the noise at the output of the magneto-resistive sensor by means of a noise optimisation circuit. By applying an external magnetic field such that nano-particles in the vicinity of the sensor are vertically magnetised, a second horizontal magnetic field component is generated at the location of the sensor. Then, the conductor current is adjusted such that the first horizontal magnetic field component compensates for the second horizontal magnetic field component. The magnitude of the conductor current necessary for this compensation is a measure for the amount of nano-particles present at the sensor.

A magneto-optic imager for NDT applications

Abstract: The paper deals with magneto-optical methods utilized for the nondestructive testing (NDT) of materials and technical components. The described imaging device (based on a garnet film) is able to operate in two different modes. In the static mode it makes visible changes in the magnetic permeability of the tested materials (e.g. the presence of Fe-α phase in austenitic steels). In the alternating mode the sensor images changes of electrical resistivity (e.g. small holes in copper foils). Examples of the application of the methods are presented and the results are discussed.

Magneto resistive elements and methods for manufacture and use of same

Abstract: The instant disclosure provides and describes a magneto resistive element comprised of a first electrode; a second electrode; and a semi conductive/conductive organic layer disposed between the first and second electrodes, wherein the magneto resistive element has a predetermined resistance (R). The magneto resistive elements provide a magneto resistive response when influenced by an applied magnetic field. The magneto resistive elements can be integrated into a variety of systems including, without limitation, magnetic field detection systems and display devices.

Magneto-electric conversion system, magneto-electric conversion apparatus and its control circuit

Abstract: PROBLEM TO BE SOLVED: To obtain sufficient magnetic field measuring accuracy which is stable for external conditions such as temperature. SOLUTION: The system is constituted of a hall element 1, a first current source 4, a coil 2, a second current source 5 and a control circuit 6. The hall element 1 detects magnetic field intensity and the first current source 4 supplies the hall element 1 with a drive current Ih. The coil 2 is arranged in the vicinity of the hall element 1. The second current source 5 supplies the coil 2 with exiting current Ic. The control circuit 6 controls the drive current Ih and the exiting current Ic. The control circuit 6 controls the current value of the drive current Ih so that the difference between the output value of the hall element 1 when the exiting current Ic is supplied to the coil 2 and the output value of the hall element 1 when the exiting current Ic is not supplied to the coil 2 becomes constant. COPYRIGHT: (C)2006,JPO&NCIPI

Fuel measuring device

Abstract: The present invention relates to a fuel measuring device, more particularly, to a fuel measuring device having a non-intrusive (or non-contact) structure between a rotor and a magneto resistive sensor, resulting in reducing of measurement errors that are usually caused by imperfect mechanical contact or corroded contacts.

Permanent magnet A.C. generator D.C. electron voltage stabilizer

Abstract: The invention relates to circuit design for converting AC current output by magneto alternator to DC current with stable voltage through phase shift, clipping and rectification, belonging to technical area of automobile motor and electrical appliances. The circuit design includes single-phase dual half wave controllable rectification loop, voltage signal sample loop and triggering loop of phase shift. Characters are that sample loop composed of R1, R2, R3, DW1, R4, T1, R5, R6, D1, D2 components etc. fetches sampling from voltage output end of magneto alternator directly. The invented device can be utilized as rectifier and stabilizer for charging voltage of magneto alternator brought by micro-mini engine to drive operation of appliances needed DC current or charge accumulators. The stabilizer possesses advantages of simple circuit, reliable operation, good performances and energy saving.

Design of a magneto-optic residual current device using aqueous ferrofluid as the sensing material

Abstract: The paper presents a design for a Magneto-Optic Residual Current Device (MORCD) using ferrofluid as the sensing material. As the selection of suitable magneto-optic material was seen as the critical phase in the design, a novel Magneto-Optical performance Indicator is proposed and verified using known optical materials. It was experimentally established that the designed MORCD is sufficiently fast and capable of detecting residual current as low as 1.51 mA.

Supplemental capacitive discharge ignition system

Abstract: A capacitive discharge ignition system for initiating combustion during cold- and hot-ignition of an internal combustion engine requiring minimal mechanical energy input. The capacitive discharge ignition system includes a magneto having a rotor, a first capacitive discharge device electrically connected to the magneto and to an ignition coil of an internal combustion engine and a second capacitive discharge device electrically connected to the first capacitive discharge device, and to the ignition coil. A mechanical startup mechanism, such as a pull-type or kick-type device, is connected to the magneto and adapted to initiate rotation of the rotor, and thereby combustion within the engine. An energy storage device is electrically connected to the second capacitive discharge device and to the magneto. The energy storage device is adapted to store energy generated by the magneto during rotation of the rotor and to provide energy to the ignition coil of the internal combustion engine.

Electronic ignition for aircraft piston engines

Abstract: An Electronic Ignition for a piston aircraft engine, which replaces conventional magneto ignitions, includes a precise engine shaft position sensor and incorporates an internal alternator as a backup electrical power source.

Magnetic random access storage

Abstract: An MRAM includes a magneto resistive element (35), which has a record layer (37) and a reference layer (38) disposed to sandwich a tunnel barrier film (36) and is configured to store data in the record layer (37). An electric current drive line (56) is disposed to selectively apply a magnetic field to the magneto resistive element (35). The record layer (37) has a first ferromagnetic layer while the reference layer (38) has a second ferromagnetic layer. Retentivity of retaining a magnetization direction of the second ferromagnetic layer is smaller than retentivity of retaining a magnetization direction of the first ferromagnetic layer, against a magnetic field applied to the magneto resistive element (35) by the electric current drive line (56).

Optical and magneto-optic Kerr effects of MnBi, Ni2MnGa, and Gd5Si2Ge2

Abstract: The magneto-optic Kerr angle spectrum of a single crystal of MnBi was measured at room temperature and also calculated with the TB-LMTO methods including the spin-orbit inter­ action. Previously measured Kerr spectra with thin films had two negative peaks, except for one film grown in ultra high vacuum. The later had a first peak and a shoulder at the second peak position, indicating the second originated from oxygen in the other films. Comparing first-principles calculations and previous thin-film results with our single crystal data indi­ cated that the second peak originated from the combination of a weak intrinsic MnBi peak and oxygen in the sample. The complex dielectric constants and magneto-optic Kerr spectra of electro-polished (100), (110), and (111) planes Ni2MnGa were measured. Also optical and magneto-optical spectra were calculated with the TB-LMTO methods including the spin-orbit interaction. Measured Kerr and optical spectra with three surfaces at room temperature had the same peak positions, but different amplitudes. The difference between (100) and (110) sur­ faces are probably due to the polishing process, not intrinsic bulk properties. Angle-dependent reflectance difference spectroscopy of (100), (010), and (001) planes GdsSigGeg, and (100) plane Tb^Si^Ge^, which are optically anisotropic materials, were measured with the Kerr spectrometer by rotating the samples. The replacing the rare earth Gd to Tb atoms and 10 % changing Ge to Si atoms did not change the spectra much. The complex dielectric con­ stants of (100) and (001) planes Gd^Si^Ge^ were measured by the spectroscopic ellipsometer. Two reflectance differences, measured by the Kerr spectrometer at near normal incidence and converted from the dielectric constants measured by ellipsometer at oblique incidence, agreed well.

Magneto-mechanical effects in nano-magnets

Abstract: The magnetoresistance curves of quench-condensed granular Ni very close to the electric percolation threshold exhibit sharp reproducible resistance jumps. These have been interpreted as signs for magneto-mechanical effects which occur in the magnetic particles due to interactions with the surrounding grains. In this paper we present additional experimental results that are consistent with a model in which the grains that act as bottlenecks in the resistance network exhibit buckling-like magneto-mechanical distortions leading to a resistance increase. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Quantitative Magneto-Optics: Flux, Current and Electric Field Imaging

Abstract: Magneto-optical imaging (MOI) is an excellent tool to visualize magnetic flux patterns in superconductors with high spatial as well as temporal resolution. Furthermore, full quantitative MOI allows the determination of main properties of the (metastable) critical state, such as Meissner and critical current density distributions or electric field distributions related to thermally activated or current driven relaxation. A key step is the accurate calibration of the magneto-optically measured light intensities into a local magnetic flux density distribution, where properties of the MO layer as well as of the imaging system have to be taken into account. In this article, we give a short introduction into flux imaging, calibration techniques, current imaging and a completely new account on electric field imaging of relaxing magnetized states of high-temperature superconducting thin films. For all methods presented, we give examples using single crystalline and bicrystalline YBa2Cu3O7 thin films.

Method of using electro-optic measurement system to measure magnetic field and using magneto-optic measurement system to measure electric field

Abstract: The present invention provides a method where electro-optic measurement system is capable of measuring the magnetic field in addition to the electric field The invented method also can be used in a magneto-optic measurement system that is capable of measuring the electric field in addition to the magnetic field Furthermore, this new method can be used in any electric field or magnetic field measurement system, and is not confined in electro-optic or magneto-optic measurement system