Abstract:
In a magnetic resonance imaging apparatus and a method for shimming such an apparatus, at each of mirror-symmetrical assemblies respectively disposed at opposite faces of a static magnetic field generator, that each include a shimming ring, an additional shimming ring is provided that is adjustable in position relative to the other shimming ring to shim the static magnetic field. Additionally or alternatively, at each face of the static magnetic field generator, a permanently magnetic arrangement is provided that is divided into a number of permanently magnetic columns respectively having different energy levels. Additionally or alternatively, magnetic bolts, such as magnetically conducting bolts or permanently magnetic bolts can be symmetrically inserted into either of the mirror-symmetric assemblies, or the permanently magnetic columns, for additionally shimming adjustment.
Abstract:
A magnetic field generating system suitable for use in a magnetic resonance apparatus has mirror-symmetrical assemblies disposed at opposite faces of a supporting structure, each assembly having a pole plate located between a pulsed magnetic field excitation coil and a static magnetic field generating source. Each pole plate is formed by a number of pole plate segments that either electrically insulated from each other, or conduct between adjacent segments only at single points, without forming a conductive loop. Eddy current propagation is thereby suppressed.
Abstract:
The present invention relates to a magnetic field adjusting device; such as may be used in MRI apparatus. The device can overcome the magnetic force to enable shimming plugs to move in a controlled continuous manner, thereby achieving continuous adjusting and accurate positioning. The magnetic field adjusting device comprises; a pair of opposing pole plates (3, 31), respectively mounted on magnetic field generating sources, forming a magnetic field space; a plurality of shimming plugs (42) movably mounted at the periphery of said pole plates (3, 31), each shimming plug (42) mounted in a radially oriented retaining groove (45), so as to be movable in the direction of the retaining groove. Additionally, or alternatively, the circumferences of the magnetic field generating sources (5, 51) are arranged with adjusting bars (71, 81) which can move perpendicular to the pole plates. As an advantage of the present invention, the magnetic field can be shimmed conveniently quickly, and accurately to improve the imaging quality.
Abstract:
A variable optical attenuator is disclosed, which attenuates a beam of light while preserving its polarization substantially independent of wavelength. The beam of light is attenuated by a filter patterned with a grating of blocking stripes with serrated edges, which partially block and partially transmit the beam of light, respectively. The serrated edges provide for low polarization dependent loss. Along a length of the filter, a mark to space ratio of blocking stripe and aperture widths increases. By a linear translation of the filter along its length attenuation can be varied to a desired value. A stepper motor with lead screw can provide a suitable linear translation to give the filter a latching property.
Abstract:
A magnetic resonance reception coil composite structure is formed by at least one rigid subassembly and at least one flexible subassembly that are connected to each other. The rigid subassembly and the flexible subassembly each include an inner conductor layer, and the inner conductor layer of the rigid subassembly and the inner conductor layer of the flexible subassembly are electrically connected. Different combinations of the rigid subassembly and the flexible subassembly can be used in multiple configurations, so that the magnetic resonance reception coil can achieve complicated shapes to meet the requirements for use at the different sites of a patient, while being comfortable and endurable for the patient.
Abstract:
A rotation positioning device for a coil of a magnetic resonance imaging apparatus, having a cavity in the coil for accommodating a part to be examined, has a backing member that can freely rotate within this accommodating cavity. The backing member is provided with a first driving member and a first rotating member, and the coil is provided with a second driving member and a second rotating member. The first driving member and the second driving member form a transmission pair, and the first rotating member can rotate relative to the second rotating member under the drive of the first driving member and the second driving member. The second driving member can be driven manually or by an external driving source connected thereto to drive the first driving member, thereby driving the backing member to rotate via the cooperation of the first rotating member and the second rotating member. Also, by appropriate configuration of parameters, such as position and size, of the first driving member and the second driving member, the rotation angle or range of the backing member can be controlled precisely and quantitatively.
Abstract:
In a signal receiving method and device for a magnetic resonance imaging system, a first loop receiver coil has a saddle receiver coil overlapped thereon, and two individual loop receiver coils or two counter rotating loop receiver coils connected end-to-end are equally spaced from the first loop receiver coil along the axial direction of the first loop receiver coil, forming a dual-loop receiver coil unit. Thus, the magnetic resonance signal generated by human tissue induces current on the dual-loop receiver coil unit following excitation of the signal. When the device is operated, the signal current induced in the saddle receiver coil, the first loop receiver coil and the dual-loop receiver coil unit respectively are added, thus increasing the output signal-to-noise ratio, improving the edge imaging effect, increasing the coverage of the coil signal and improving the signal homogeneity in the imaging area.
Abstract:
A method for producing clear, concentrated sweet potato juice, including: a) cleaning, peeling, crushing, and gelatinizing a raw material of sweet potatoes to yield a sweet potato paste, and squeezing the sweet potato paste to obtain skin dregs and a squeezed clear juice; b) performing enzymolysis to part of the skin dregs and adding the hydrolyzed skin dregs to the sweet potato paste for squeezing; c) performing enzymolysis and filtering to the squeezed clear juice to obtain a sweet potato clear juice; d) combining the rest part of the skin dregs and sweet potato skins generated during the peeling process to obtain a sweet potato residue; e) extracting dietary fiber from the sweet potato residue; and f) adding the dietary fiber to the sweet potato clear juice and post-treating the sweet potato clear juice.
Abstract:
A variable optical attenuator is disclosed, which attenuates a beam of light while preserving its polarization substantially independent of wavelength. The beam of light is attenuated by a filter patterned with a grating of blocking stripes with serrated edges, which partially block and partially transmit the beam of light, respectively. The serrated edges provide for low polarization dependent loss. Along a length of the filter, a mark to space ratio of blocking stripe and aperture widths increases. By a linear translation of the filter along its length attenuation can be varied to a desired value. A stepper motor with lead screw can provide a suitable linear translation to give the filter a latching property.