167results about How to "Improve the uniformity of the magnetic field" patented technology

The invention discloses a near-field plume mass-spectroscopic diagnostic E*B probe based on the Faraday cup and belongs to the technical field of plasma mass-spectroscopic diagnosis. The probe mainly applied to measuring near-field plumes of an ion thruster and of a Hall thruster comprises a central frame, ferrite permanent magnets, a flat electrode plate, an electrode plate holder, a collimator tube, a drift tube, a Faraday cup, six carbon steel shells and an anti-sputtering heat-insulating layer. According to the connectional relation, the central frame is used as a core part, the ferrite permanent magnets are distributed on upper and lower surfaces of the central frame, the electrode plate is fixed in the central frame, and an orthogonal electromagnetic field area is formed. The six carbon steel shells are used for packaging, and the front ends of the shells are coated with an anti-sputtering heat-insulating layer. The collimator tube of stainless steel and the drift tube are fitly fixed to the centers of two ends of the central frame through shaft holes. Ions different in valence are screened by adjusting voltage among the electrode plates, univalent and bivalent ion currents are acquired with the Faraday cup of aluminum, and the ratio of near-field plum bivalent ions is acquired by analytical computing.

It is an object of the present invention to achieve a magnetic field with high uniformity and low skew angle in a dipole ring magnetic field generating apparatus. There is provided a permanent magnet type magnetic field generating apparatus comprising: a plurality of permanent magnet pieces disposed in a ring shape so that a substantially unidirectional magnetic field is generated in a space within the ring, the permanent magnet pieces having the magnetization direction undergoing one rotation over a half-circumference of the ring, the permanent magnet pieces having substantially the same magnetic strength, and the permanent magnet pieces being disposed so as to form indentations and protrusions toward a center axis of the ring, or having a shape having indentations and protrusions facing the center axis.

The invention discloses a Holbach magnet shim coil and a design method thereof. Aimed at the structural characteristic of a Holbach magnet and the direction of a main magnetic field, a current density function is designed flexibly according to the structural feature of the magnetic field, the relation between the current density and the main magnetic field is derived by utilizing the Biot-Savart Law, a current distribution function is inverted, and the coil structure is optimized by considering requirements for parameters including the power loss function and the linearity of the shim coil. Coils of two different structures are provided for the Halbach magnet, each coil structure has advantages and disadvantages in the aspects of structural complexity and performance, and the coils can be selected flexibly according to practical requirements.

A uniform magnetic field may provide better performance in wireless power transmitters due to smaller impedance variations in an output of a power amplifier of a wireless power transmitter and also allow for wireless power transmitter pads to be thinner. One aspect of the disclosure provides a device for wireless power transfer. The device comprises a substantially planar transmit antenna that is configured to generate a magnetic field. The device also comprises a pad having a charging surface. At least a portion of the transmit antenna is disposed in the pad. The device also comprises a ferromagnetic material having a shape and a position relative to the transmit antenna. At least one of the shape or position of the ferromagnetic material, or a combination thereof, is selected to modify a distribution of the magnetic field at the charging surface.

Certain example embodiments relate to sputtering target backing tube that are slightly ferromagnetic, thereby providing small-scale shunting that reduces the occurrence or magnitude of short-range magnetic field deviations during magnetron sputtering with cylindrical sputtering targets. For example, backing tube allows may be carefully optimized to be somewhat ferromagnetic, thereby enhancing the uniformity of the magnetic field generated by the magnet bar. In certain example embodiments, short range magnetic field deviations may be reduced to less than about 5% from average, more preferably less than about 2% from average, and still more preferably less than about 1% from average. Such short range magnetic field deviation reducing target backing tubes may be used in along with, or in place of, shims or shunts that address long range magnetic field deviations.

A ferrofluid power generator with micro vortex generator is disclosed, which is capable of generating an induced current by enabling a ferrofluid having a plurality of magnetic particles to flow in a closed circuit, the device comprising a vortex generator and a induced current unit. The vortex generator further comprises a first inlet, a first outlet and a plurality of cavities, which is capable of accelerating the rotation speed of the magnetic particles by virtue of employing the plural cavities to enable the magnetic particles to rotate while the ferrofluid passing through the plural cavities. The induced current unit is substantially a tube having a second inlet and a second outlet, where the second inlet is coupled to the first outlet of the vortex generator for accepting the ferrofluid with rotating magnetic particles to flow therein and through so as to induce a change of magnetic flux to occur and generate an induced current accordingly.

A superconducting magnet apparatus. By forming one or more holes in each of platelike ferromagnetic substances forming a magnetic shield for focusing the magnetic flux generated by superconducting coils, the flow of lines of magnetic flux is adjusted. Thereby, a static magnetic field in a measurement space is corrected. By disposing coupling tubes for supporting two cooling vessels housing superconducting coils on the rear side with respect to a central axis (Z axis) of the measurement space of the vertical direction, access to the subject is facilitated. In addition, the magnetic shield has an opening portion wider than the superconducting magnet on its side face. After the magnetic shield has been assembled, the superconducting magnet can be inserted from the opening portion.

A superconducting magnet apparatus obtains high magnetic field uniformity without increasing the volume of a magnetic material even against disturbances. The superconducting magnet apparatus has a circular superconducting coil which generates a magnetic field; a coil vessel which contains the superconducting coil 11 together with refrigerant; a thermal shield arranged so as to surround the coil vessel; a vacuum vessel with inside kept vacuum which surrounds the thermal-shield; and magnetic materials and for correcting the magnetic field, the magnetic materials being arranged in the vacuum vessel; wherein the magnetic materials and are supported by a heat-insulation support medium fixed to the coil vessel.

A generator of time-variable magnetic fields of a magnetic resonance device having an examination space for registering at least one area to be examined of an item being examined has the following features: the conductors of a gradient coil arrangement of the generator define an area at least partially surrounding the examination space, said area contains at least a partial area which is free from conductors of the gradient coil arrangement and which contains conductors of a radio frequency antenna of the generator, and a field flowback space, inter alia for fields of the radio frequency antenna, extends proceeding from the partial area away from the examination space and is delimited beyond said partial area by a radio frequency shield.

In a nuclear magnetic resonance spectrometer, the shape of a detection coil is changed from a conventional cage type to a solenoid type of higher sensitivity. Accordingly, differing from the conventional superconductive magnet of multilayer air core solenoids, a superconductive magnet is right and left divided to split magnets for generating 11 T, preferably, 14.1 T in the horizontal direction, and the magnetic field uniformity is set to 0.001 ppm or less and the temporal stability is set to 0.001 ppm or less.

In a nuclear magnetic resonance spectrometer, the shape of a detection coil is changed from a conventional cage type to a solenoid type of higher sensitivity. Accordingly, differing from the conventional superconductive magnet of multilayer air core solenoids, a superconductive magnet is right and left divided to split magnets for generating 11 T, preferably, 14.1 T in the horizontal direction, and the magnetic field uniformity is set to 0.001 ppm or less and the temporal stability is set to 0.001 ppm or less.

The invention relates to a multistage passive uniform-field permanent magnet for nuclear magnetic resonance detection. The multistage passive uniform-field permanent magnet is characterized in that the permanent magnet comprises a main magnet, a magnet-conductive steel yoke rack and a multistage uniform field device, wherein the main magnet is composed of a pair of permanent magnet poles; the magnet-conductive steel yoke rack comprises an upper magnet-conductive cover (1) and a lower magnet-conductive cover (7) which are arranged in a manner of facing each other, a left magnet-conductive supporting rack (5) and a right magnet-conductive supporting rack (12) which are arranged in a manner of facing each other; the main magnet comprises an upper permanent magnet pole (2) and a lower permanent magnet pole (8) which are arranged in a manner of facing each other; and the multistage uniform field device comprises a first auxiliary uniform field magnetic block (4), a second auxiliary uniform field magnetic block (6), a third auxiliary uniform field magnetic block (11), a fourth auxiliary uniform field magnetic block (13), a first gradient uniform field ring (9) and a second gradient uniform field ring (10). The multistage passive uniform-field permanent magnet has advantages of high magnetic field uniformity, simple structure, high openness, easy production, easy assembling, etc. Furthermore the multistage passive uniform-field permanent magnet has good application prospect in a portable miniature nuclear magnetic resonance detection system.

This invention provides arrays of counter rotating current surface coils for simultaneous reception and transmission with a volume coil for improved signal-to-noise ratio and radio frequency field homogeneity for in particular high-field (4-8 T) imaging of deep body regions, such as central brain structures.

The invention provides a three-transmitting-coil coupling mechanism and a magnetic coupling WPT system formed by the three-transmitting-coil coupling mechanism. A transmitting end comprises a first coil, a second coil and a third coil. The first coil is a multi-turn coil formed by winding an independent wire, and a peripheral charging area is formed; the second coil and the third coil are multi-turn coils which are formed by connecting another independent wire in series in an unwound area in the first coil and winding in sections, and a central charging area is formed; and non-winding areas are reserved in the third coil and between the third coil and the second coil, the first coil is connected with the first resonance compensation circuit and works at a first resonance frequency, and thesecond coil and the third coil are connected in series and then are connected with the second resonance compensation circuit and work at a second resonance frequency. The system has the effects thatthe anti-offset capability is improved, the system cost is reduced, and the system can be applied to mobile equipment application occasions with different power levels.