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

MR spectroscopy and imaging method for imaging pulmonary and cardiac vasculature and the cardiac region and evaluating blood flow or circulatory deficits use dissolved phase polarized 129Xe gas and large flip angle excitation pulses. Pulmonary and cardiac vasculature MRI images are obtained by delivering gas to a patient via inhalation such as with a breath-hold delivery-procedure, exciting the dissolved phase gas with a large flip angle pulse, and generating a corresponding image. Preferably, the image is obtained using multi-echo imaging techniques. Blood flow is quantified using low field MR spectroscopy and an RF excitation pulse with a frequency which corresponds to the resonance of the dissolved phase 129Xe.

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 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 magnet arrangement includes (a) a first and a second head ring magnet each having a substantially circular geometry with respect to a centre axis and (b) a central ring magnet having a substantially circular geometry with respect to a centre axis. The central ring magnet is disposed between the first and second head ring magnet in direction of the centre axis. At least one of the magnets includes a first number of first magnets having at least one trapezoidal cross section and a second number of second magnets having at least one rectangular cross section. The second magnets are disposed in between the first magnets in circumferential direction. With this geometrical arrangement, magnets having a trapezoidal cross section include a guidance for a magnet having a rectangular cross section allowing the movements in radial direction of these last magnets.

The invention discloses a full-open permanent magnet for MRI, wherein the permanent magnet comprises: full-open main structure of a rectangular structure composed of two vertical yokes arranged left and right symmetrically and two transverse yokes arranged up and down symmetrically with an air gap zone of the permanent magnetic positioned in the middle of the full-open main structure; up and down two parallel opposite main poles which are respectively arranged on the sides close to the air gap zone of and connected with the up and down two transverse yokes; and up and down two parallel opposite pole plates which are respectively arranged on the sides close to the air gap zone of and connected with the up and sown two main poles. The invention enormously reduces the weight of the yokes, improves the shimming efficiency and increases the openness of the magnetic field.

This invention relates to a strong magnetic field magnet body avoiding abnormal magnetization, in which, 8-64 blocks of NdFeB unit magnets are conglutinated to a hollow column, soft magnetic material is set on the central position of the magnet body and the outside surface of which is blocked by a metal shell characterizing that the unit magnets are divided into inside and outside two layers adhered by NdFeB of different characters or adhered by NdFeB and soft magnet material, and the outer layer of the unit magnets set vertically is NdFeB and the inter layer is soft magnet material turning narrower along the core direction and flux in the magnetic channels gathers into a central gap gradually and small soft magnet material is also set in either unit magnet, the width of the bottom edge of this invented soft magnet material is wider than that in the current technology. This invention also applies a fixed shell of magnetic shield.

A method and apparatus for improving spectral resolution of an NMR measurement in the presence of an inhomogeneous magnetic field. According to one embodiment, a method producing a high resolution nuclear magnetic resonance (NMR) spectrum for a sample in an inhomogeneous magnetic field may comprise generating a first magnetic pulse and a second magnetic pulse, the first and second magnetic pulses being separated in time by a first time period, during the first time period, generating a gradient pulse, repeating the steps of generating the first and second magnetic pulses and generating the gradient pulse N times for different values of a field strength of the gradient pulse, wherein N is an integer greater than one, after each second magnetic pulse, acquiring a signal from the sample, and producing a reconstructed high resolution NMR spectrum from the acquired signals.

The invention relates to a sensing device and a positioning method thereof, in particular to a magnetic array position sensing device and a positioning method thereof. The magnetic array position sensing device comprises a permanent magnetic body device 1 which is provided with a magnetic array 101 and a magnetic sensitive element device 2 which is matched with the permanent magnetic body device 1 and is provided with a magnetic sensitive element array 201, wherein the magnetic sensitive element device 2 is fixed on a main circuit board 7 which contains a distance test device 3, and the magnetic sensitive element array 201 is fixed on the magnetic sensitive element device 2 through a fixing device 4. The magnetic array position sensing device has the following advantages that: 1. an independent positioning plate is adopted, and the magnetic sensitive element is welded on the positioning plate, so the position error of the magnetic sensitive element is reduced; 2. the relationship between the width of the magnetic body array unit and the gap of the magnetic sensitive element is re-designed, so under the condition that the precision of the system is maintained, the distance between the magnetic sensitive elements is enlarged, the consumption of the magnetic sensitive element is reduced, and the cost of the device is reduced.

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.

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 primary magnetic coil system is composed of multiple coil portions supported in predetermined relative positions, the multiple coil portions being electrically connected in series and carrying a common primary coil current during operation. The system has a corrective component that selectively causes a corrective electric current to be supplied to a subset of the coil portions.

The invention discloses a method for detecting the aging degree of an insulator sample and solves the problem of low magnetic field uniformity of an existing insulator aging degree magnetic resonance detection magnet. The method comprises the following steps: selecting twelve cubic magnet sub-modules (1) with the same size and the same magnetic material, and magnetizing, wherein all cubic magnet sub-modules are the same as one another in terms of magnetizing strength and magnetizing direction; uniformly distributing the twelve cubic magnet sub-modules on the same circumference at intervals with equal radian, arranging a detection coil (15) in the circle center of the same circumference on which the twelve cubic magnet sub-modules are uniformly distributed, detecting and analyzing a signal in the detection coil, electromagnetically exciting the insulator sample, and processing a generated magnetic resonance induction decay signal through a pre-amplifier, a frequency mixer and an analog-to-digital converter in sequence; and observing and analyzing parameters such as the height of each characteristic spectral line on a spectral graph, and comparing the parameters with standard data to judge the aging degree of an insulator.

A magnetic resonance probe head (40) comprises a vacuum container (43) in which several RF resonator coils (31, 32; 51-54, 61-64) are disposed that can be cryogenically cooled and which are each designed as planar coils disposed parallel to a z direction. All of the RF resonator coils (31, 32; 51-54, 61-64) have a larger extension in an x direction (RSx) than in a y direction (RSy), wherein the x, y, z directions form a rectangular coordinate system. A central tube block (33; 81; 111; 121; 171; 181) is disposed between the RF resonator coils (31, 32; 51-54, 61-64) and has a recess (34, 112, 122) for a test sample (35), which is elongated in the z direction. The central tube block (33; 81; 111; 121; 171; 181) partially delimits the vacuum container and the recess (34, 112, 122) is disposed outside of the vacuum container (43). The central tube block (33; 81; 111; 121; 171; 181) has a larger extension in the x direction (ZRx) than in the y direction (ZRy) in the area between the RF resonator coils (31, 32; 51-54, 61-64). The inventive probe head improves the sensitivity, in particular, for small and round test samples.

There is provided a magnetic field generator (10) and a method of manufacturing it, capable of reducing decline in the magnetic field intensity and deterioration of magnetic field uniformity during transportation.

The magnetic field generator (10) includes a pair of plate yokes (12a), (12b). The plate yokes (12a), (12b) are opposed to each other, with their opposing faces provided with permanent magnet assemblies (14a), (14b) respectively. The permanent magnet assemblies (14a), (14b) have faces opposing to each other, to which pole pieces (16a), (16b) are fixed respectively. The permanent magnet assemblies (14a), (14b) include permanent magnets (18). The pole pieces (16a), (16b) include annular projection (24) and permanent magnets (28) for prevention of magnetic flux leakage provided on an outer side surface of the annular projection (24). The permanent magnets (18), (28) include R—Fe—B magnets magnetized to a magnetization rate not smaller than 80% and not greater than 99.9%. When manufactured, the assembled magnetic field generator (10) is heated in its entirety at a temperature not lower than 40° C. and not higher than 70° C.

Improved current sensing methods and apparatus and conductor apparatus are presented for sensing current in a bus bar or other conductor using one or more circular magnetic sensors or multiple magnetic sensors disposed on a substrate in a pattern surrounding a longitudinal path within the outer periphery of the conductor to avoid or mitigate sensed magnetic field crosstalk and to facilitate use of high sensitivity magnetic sensors at locations inside the conductor periphery in which the magnetic field is relatively small.

An electromagnetic flow meter for measuring flow rate of a fluid passing therethrough includes a conduit defining a fluid inlet, a fluid outlet and a measuring section positioned between the inlet and the outlet. The flow meter also includes a single coil for generating a magnetic field across the measuring section and electrodes for detecting induced electrical potential due to the fluid passage. The flow meter also includes means for conditioning the flow through the measuring section. The combination of the single coil and the flow conditioning means provides a flow meter with a desired level of accuracy. The single coil and the electrodes may be arranged so that the integral of a weight function, which defines the sensitivity of the flow meter to fluid velocity through different parts of the measuring section, over the first half of a measuring section closest to the coil is between 0.4 and 1.3 times the integral of the weight function over the other half of the measuring section.