Abstract: According to one embodiment, a gradient coil unit for a magnetic resonance imaging apparatus includes gradient coils for forming gradient magnetic fields in mutually orthogonal three axis directions. At least one of the gradient coils includes a conductor part along a coil pattern and a holding part holding the coil pattern. A passage of a coolant is formed inside at least one of the conductor part and the holding part. The passage has a non-constant cross section.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for detecting electronic counter measure (ECM) signals and embedding covert messages in radar or sonar signals. In one aspect, a method for detecting ECM signals includes receiving a radar return signal from an object. The method includes determining whether radar return signal includes a TM signal, and identifying the radar return signal as a skin return signal or an electronic counter measure signal based on whether the radar return signal includes the TM signal.

Abstract: Method, system and non-transitory computer-accessible medium can be provided for performing magnetic resonance spectroscopy for at least one structure. For example, with such method and/or computer-accessible medium, it is possible to receive information related to a substantially simultaneous acquisition of a stimulated echo pathway and a double spin echo associated with at least one portion of the at least one structure.

Abstract: An RF (radio frequency) positioning system and related method for automated or assisted eye-docking in ophthalmic surgery. The system includes an RF detector system on a laser head and an RFID tag on a patient interface to be mounted on the patient's eye. The detector system includes four RF antennas located on a horizontal plane for detecting RF signals from the RFID tag, where one pair of antennas are located along the X direction at equal distances from the optical axis of the laser head and another pair are located along the Y direction at equal distances from the optical axis. Based on relative strengths and phase difference of the RF signals detected by each pair of antennas, the RF detector system determines whether the patient interface is centered on the optical axis. The RF detector system controls the laser head to move toward the patient interface until the latter is centered on the optical axis.

Abstract: Hundreds of thousands of concrete bridges and hundreds of billions of tons of concrete require characterization with time for corrosion. Accordingly, protocols for rapid testing and improved field characterization systems that automatically triangulate electrical resistivity and half-cell corrosion potential measurements would be beneficial allowing discrete/periodic mapping of a structure to be performed as well as addressing testing for asphalt covered concrete. Further, it is the low frequency impedance of rebar in concrete that correlates to corrosion state but these are normally time consuming vulnerable to noise. Hence, it would be beneficial to provide a means of making low frequency electrical resistivity measurements rapidly. Further, prior art techniques for electrical rebar measurements require electrical connection be made to the rebar which increases measurement complexity/disruption/repair/cost even when no corrosion is identified.

Abstract: A magnetic positioning system and related method for automated or assisted eye-docking in ophthalmic surgery. The system includes a magnetic field sensing system on a laser head and a magnet on a patient interface to be mounted on the patient's eye. The magnetic field sensing system includes four magnetic field sensors located on a horizontal plane for detecting the magnetic field of the magnet, where one pair of sensors are located along the X direction at equal distances from the optical axis of the laser head and another pair are located along the Y direction at equal distances from the optical axis. Based on relative magnitudes of the magnetic field detected by each pair of sensors, the magnetic field sensing system determines whether the patient interface is centered on the optical axis. The system controls the laser head to move toward the patient interface until the latter is centered on the optical axis.

Abstract: An X-ray-diagnostic apparatus generates time-series first vessel images corresponding to a first direction, and generates second vessel image corresponding to a second direction. The apparatus generates third vessel images corresponding to the second direction, by transforming more than one piece out of the first vessel images based on a blood vessel shape in one of the first vessel images and a blood vessel shape in at least one of the second vessel image, the third vessel image corresponding to respective time phases of the first vessel images. The apparatus generates first color image corresponding to the first direction by using more than one piece out of the first vessel images, and generates second color image corresponding to the second direction by using more than one piece out of the third vessel images. The apparatus displays a stereoscopic image based on the first color-image and the second color image.

Abstract: A method is provided for ascertaining at least one item of movement information describing a sought movement as a partial movement of an overall movement in an at least partially moved examination region. In the method, at least one excitation signal having a first frequency band is output and receiving signals generated by the excitation signal are recorded with a receiving coil arrangement, (e.g., a receiving coil arrangement of a magnetic resonance device), having a plurality of receiving channels. The coils of the receiving coil arrangement are designed to record a receiving frequency band including the first frequency band, wherein for ascertaining the movement information the complex receiving signals of the receiving channels are combined at one instant according to a combination specification ascertained over a period by an analysis of the receiving signals that identifies at least one component of a movement that contributes to the sought movement.

Abstract: Radio frequency (RF) shields used with magnetic resonance imaging (MRI) apparatus may experience gradient field induced eddy currents and RF field induced eddy currents. These eddy currents can cause the RF shield to heat up at an undesirable rate. RF shields are designed to have a desired degree of RF shielding and a desired heating attribute. Design goals for RF shields include gradient field transparency and RF field opacity, both of which can be influenced by eddy currents. Example methods identify a gradient field that will induce eddy currents and identify an RF field that will induce eddy currents. If a region on the RF shield is identified where the desired heating attribute will not be achieved, then a pattern of axial cuts and azimuthal cuts can be made in the RF shield to reduce gradient eddy current heating in the RF shield while maintaining desired RF shielding.

Abstract: In a method and apparatus for acquiring magnetic resonance data from a slice package composed of multiple measured slices as a target volume by executing a measuring sequence, prior to each scan of one of the measured slices, the measuring sequence includes a preparation pulse associated with the measured slice for signal suppression of a type of saturation molecule. This said preparation pulse acts on the entire target volume, and a pulse parameter of the preparation pulse is chosen for a measured slice group, composed of at least one measured slice, as a function of resonance information on the contiguous partial volume covered by the measured slice group.

Abstract: The uncertainty, sensitivity, and/or standard deviation for a patient-specific hemodynamic quantification is determined. The contribution of different information, such as the fit of the geometry at different locations, to the uncertainty or sensitivity is determined. Alternatively or additionally, the amount of contribution of information at one location (e.g., geometric fit at the one location) to uncertainty or sensitivity at other locations is determined. Rather than relying on time consuming statistical analysis for each patient, a machine-learnt classifier is trained to determine the uncertainty, sensitivity, and/or standard deviation for the patient.

Abstract: The present invention provides a rock movement sensor including an inertial measurement assembly, a control assembly responsive to said inertial measurement assembly and a communication assembly coupled to the control assembly. The control assembly is arranged to determine a displacement associated with a blast or drop based on signals from the inertial measurement assembly. The communication assembly is preferably a wireless communication assembly. A surface unit corresponding to the rock movement sensor is provided which includes a processor programmed to operate a communications assembly to receive displacement data from the rock movement sensor. Consequently, the movement of an ore body due to a blast may be determined by locating a number of the rock movement sensors at known locations about the ore body prior to the blast and subsequently retrieving data values indicating a displacement relative to the known locations from the rock movement sensor post blast.

Abstract: A system and method for an electron paramagnetic resonance imaging (EPRI) system includes a magnet configured to apply a static magnetic field to a subject to be imaged and a gradient coil configured to apply a magnetic field gradient to the static magnetic field. The system also includes a parallel plate waveguide (PPWG) configured to use a traveling wave to generate a radio frequency (RF) magnetic field over a volume of interest (VOI) in the subject to elicit EPRI data from the VOI and a processor configured to reconstruct the EPRI data into an image of the VOI.

Abstract: An RF choke resonator assembly has a cylindrical magnetic field shielding case with openings at two ends thereof, a magnetic field shielding plate and a winding skeleton, and a capacitive plate inside the case. The magnetic field shielding plate closes the opening at one end of the case, and has a through-hole allowing a cable to pass there through. The cable is wound on the winding skeleton. The capacitive plate is disposed opposite the magnetic field shielding plate in the case, separated therefrom by the winding skeleton, and is electrically connected to the case in a closed manner. The capacitive plate has a through-hole allowing the cable to pass there through. The capacitive plate is remote from the other opening case end opposite the opening closed by the magnetic field shielding plate. An insulation space is formed at that other opening, having a length in the axial direction greater than or equal to one quarter of the length of the magnetic field shielding case in the axial direction.

Abstract: A method for detecting a magnetic field acting on a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers may include controlling an optical excitation source and an RF excitation source to apply a pulse sequence comprising two optical excitation pulses and two RF excitation pulses to the NV diamond material, receiving a light detection signal from an optical detector based on an optical signal emitted by the NV diamond material due to the pulse sequence, measuring a first value of the light detection signal at a first reference period, the first reference period being before a period of the light detection signal associated with the two RF excitation pulses provided to the NV diamond material, measuring a second value of the light detection signal at a second reference period, the second reference period being after the period of the light detection signal associated with the two RF excitation pulses provided to the NV diamond material, and computing a measurement signal based on the me

Abstract: A Magnetic Particle Imaging (MPI) system including a mechanically-rotatable magnet generating a field-free line, where the system is capable of acquiring a plurality of projections at a plurality of rotation angles, and where the projection acquisition includes positioning the field free line at a plurality of positions at the plurality of angles.

Abstract: THIS INVENTION relates to a method and a device for detecting a target material at a distance. The device includes a means for indicating the direction to the target material, a primary energy source for subjecting a sample material to energy and a means for sensitizing the device, and specifically an indicating means thereof, such that the indicating means detects target material similar to the sample material.

Abstract: An apparatus for measuring nuclear magnetic resonance (NMR) properties of subsurface formations includes a magnet for pre-polarizing nuclear spins in the formations. A plurality of transmitter antennas is spaced apart along a length of the apparatus. The apparatus includes at least one of a receiver circuit selectively coupled to at least one of the plurality of transmitter antennas and a separate receiver antenna. The apparatus includes circuitry for applying radio frequency current pulses selectively to each of the plurality of transmitter antennas such that during a NMR measurement sequence while the apparatus is moving substantially only those of the plurality of transmitter antennas having radio frequency current pulses applied thereto are disposed longitudinally along a same region of interest in the subsurface formations.

Abstract: An exam room shielding (10) for electromagnetically shielding a magnetic resonance imaging system (2) includes: a ceiling, a floor, side walls (11) interconnecting the ceiling and the floor, and a tubular shielding device (12), which is arranged to surround an examination tube (3) of the magnetic resonance imaging system (2). Both longitudinal ends (13) of the tubular shielding device (12) are circumferentially connected to openings (14)of the side walls (11) which form the outline of an U-shaped room (15) with the longitudinal ends (13) of the tubular shielding device (12) interconnecting the lateral flanks (16) of the U-shaped room (15). A magnetic resonance imaging system (2) includes an exam room (1), with the above exam room shielding (10). An additional treatment or diagnosis device (7) can be located at an outer circumference of the tubular shielding device (12). This separates the space inside the exam room into a compartment free of RF noise, i.e.

Abstract: Magnetic resonance imaging (MRI) systems and methods to effect MRI data acquisition with reduced noise in fast spin echo (FSE) and spin echo (SE) implementations are described. The improved MRI data acquisition is performed by acquiring k-space data while maintaining a constant or near constant slice select gradient amplitude throughout a sequence kernel. The acquired k-space data can then be used to generate an MR image.

Abstract: An apparatus includes a hydrogel including a metallic compound, a surfactant, an acid, agarose and water. The hydrogel is substantially colorless. A radiated hydrogel having a color is formed when the hydrogel receives a low dose of ionizing radiation.

Abstract: Nuclear magnetic resonance apparatuses and systems are described. In an example, the apparatus comprises a tool housing and a magnet assembly disposed within the tool housing to produce a magnetic field in a volume in a geological formation. An external housing containing an antenna assembly is coupled to the tool housing.

Abstract: A magnetic resonance method includes providing a pulse sequence that affects different measurement regions in presence of a magnetic field gradient, the pulse sequence having multiple pulse shapes and multiple characteristic interecho intervals (TEs).

Abstract: A buckle with a first pawl that is biased by a pair of magnets that are oriented in opposition to each other to provide a repelling force, and with a second pawl that is biased by another pair of magnets that are oriented in opposition to each other to provide a repelling force.

Abstract: Acoustic noise reduction is achieved in a high-speed imaging method such as a phase-compensation type GE sequence, which is not provided with sufficiently long intervals for applying the gradient magnetic field pulses. A band-stop filter is used to reduce components of a frequency band in the gradient magnetic field waveform, having a high sound pressure level being a source of sound, thereby performing the noise reduction. In general, when a band of the gradient magnetic field is reduced, the waveform is likely to be considerably distorted, failing to satisfy imaging conditions. Therefore, the distorted waveform is shaped so that the imaging conditions are satisfied. The sound pressure level of the gradient magnetic field waveform is calculated by using a response function inherent to the device.

Abstract: A method for improving shim pre-settings of a magnetic resonance device and a magnetic resonance device are provided. Efficient computation of shim settings for magnetic resonance imaging is provided by the method. The method includes loading of shim pre-settings from a database, creating shim settings using the shim pre-settings for recording magnetic resonance image data of an examination object by a magnetic resonance device, and activating a shim unit of the magnetic resonance device for recording the magnetic resonance image data. The method also includes using the created shim settings, improving the shim pre-settings using the created shim settings, and storing the improved shim pre-settings in the database.

Abstract: Methods and systems are presented in this disclosure for estimation of formation properties and pipe properties using ranging measurements. Embodiments of the present disclosure utilize ranging measurements to first determine a defined slope (e.g., leakage rate) of an electrical current signal flowing along a wellbore. The determined slope (e.g., leakage rate) may be then used to estimate properties of a formation surrounding the wellbore (e.g., formation resistivity) and properties of a conductive material (casing pipe) deployed in the wellbore (e.g., pipe resistance). Based on the estimated properties of the formation and the conductive material, drilling operation in a drilling well can be adjusted, and repair of defects or mechanical deformations on the casing pipe can be initiated.

Abstract: An optical pumping and isotropic measurement magnetometer. The magnetometer is all-optical in the sense that resonance between Zeeman sub-levels is induced by modulating the intensity or the frequency of the pump beam. Resonance is detected either using the pump beam itself or an unmodulated probe beam. The pump beam is linearly polarised and its polarisation direction is kept constant relative to the direction of the magnetic field to be measured, so that a measurement independent of the orientation of the field can be made.

Abstract: A method for carrying out two-field nuclear magnetic resonance (=2FNMR) measurements involves preparing a sample (9a) in a first working volume (5) of a highly homogeneous magnetic field with a first field strength; transferring the sample (9a) to a second working volume (7) with a magnetic field having lower homogeneity and having a second field strength, wherein the first field strength is at least 2 Tesla larger than the second field strength; manipulating the sample (9a) at the second working volume (7) by applying a sequence of radio-frequency (=RF) and/or field gradient pulses; transferring the sample (9a) back to the first working volume (5); and detecting an NMR signal of the sample (9a) in the first working volume (5). The method allows for NMR experiments with which more and/or improved quality information about an investigated sample can be obtained.

Abstract: Measuring a sample includes providing a magnetic field at the sample using an electromagnetic field resonator. The electromagnetic field resonator includes two or more resonant structures at least partially contained within dielectric material of a substrate, at least a first resonant structure configured to provide the magnetic field at the sample positioned in proximity to the first resonant structure. The sample is characterized by an electron spin resonance frequency. A size of an inner area of the first resonant structure and a number of resonant structures included in the electromagnetic field resonator at least partially determine a range of an operating resonance frequency of the electromagnetic field resonator that includes the electron spin resonance frequency. Measuring the sample also includes receiving an output optical signal from the sample generated based at least in part on a magnetic field generated by the electromagnetic field resonator.

Abstract: The present invention is directed to a system and method for magnetic resonance imaging including an extended Fourier transform-based velocity-selective pulse train design with a pair of refocusing pulses within each velocity encoding step and accompanying phase cycling between different velocity encoding steps. The present invention is robust to B0/B1 field inhomogeneity and eddy current effects. The utility of this technique, through a velocity-selective inversion pulse, is demonstrated in a 2D velocity-selective arterials spin labeling study, which shows a reasonable agreement in CBF quantification with the standard PCASL method.

Abstract: An MRI system for performing time resolved MR imaging of an object with grouped data acquisition is provided. The MRI system includes an MRI controller in electronic communication with a magnet assembly and operative to sample a group of data points within a first region of a k-space. The first region includes a central sub-region and a first peripheral sub-region. The MRI controller is further operative to sample a group of data points within a second region of the k-space. The second region includes the central sub-region and a second peripheral sub-region different from the first peripheral sub-region.

Abstract: Systems and methods are provided that acquire image data of a first location of a region of interest (ROI) when located in a field of view of a medical imaging system as a contrast material injected into the ROI passes through the first location. The systems and methods further determine from the image data of the first location when a first contrast metric is reached, and after determining the image data of the first location, position the second location of the ROI in the field of view of the medical imaging system. The systems and methods further acquire image data of the second location as the contrast material passes through the second location, and determine from the image data of the second location when the contrast material reaches a second contrast metric.

Abstract: An anti-saturation device for a ground magnetic resonance signal amplifying circuit has a receiving coil connected with a band-pass filter circuit through a pre-amplifying circuit and a programmable amplifying circuit. The programmable amplifying circuit is connected with an AD acquisition card through the band-pass filter circuit. The band-pass filtering circuit is connected with a computer through the AD acquisition card, and the AD acquisition card is connected with an emitting system through the computer. An automatic amplification factor adjusting module is embedded into a nuclear magnetic resonance detector, and can also directly replace a receiving amplification circuit of the nuclear magnetic resonance detector to work independently.

Abstract: Methods of generating a gradient signal, gradient signal generators and magnetic resonance imaging systems are provided. In one aspect, a method includes obtaining a target amplitude and a target duration associated with a target precision corresponding to the gradient signal; generating a first actual amplitude by intercepting the target amplitude according to an actual precision of a DAC; generating a second actual amplitude according to the first actual amplitude, wherein a difference between the second actual amplitude and the first actual amplitude is 1; determining a first actual duration of outputting the first actual amplitude and a second actual duration of outputting the second actual amplitude according to the target amplitude, the target duration, the first actual amplitude and the second actual amplitude; controlling the DAC to output the first actual amplitude according to the first actual duration and output the second actual amplitude according to the second actual duration.

Abstract: A receiver assembly of a magnetic resonance (MR) system for generating MR recordings of an examination object includes a plurality of reception channels for receiving and amplifying MR signals from reception coils of the MR system connected therewith. A calibration data memory for storing calibration data for the plurality of reception channels is arranged on the receiver assembly. The receiver assembly includes a data link for transmitting the calibration data to the MR system.

Abstract: A nuclear magnetic resonance (NMR) logging tool for use in wellbore logging operations is provided. The NMR logging tool features a three-part permanent magnet arrangement that reduces the attractive force between the NMR tool and casing, allowing the NMR tool to be lowered through wellbores of any size. Additionally, the disclosed arrangement of permanent magnets in the NMR tool may facilitate an effective pre-polarization of portions of the formation at different logging speeds. Further, the disclosed arrangement of permanent magnets in the NMR tool may provide a uniform or substantially uniform static magnetic field within the antenna window of the radio frequency (RF) antenna used to perform the measurements. The second magnet may be positioned between the first and third magnets in a longitudinal direction along the NMR tool, and a radio frequency (RF) antenna may be disposed adjacent the first magnet.

Abstract: In a magnetic resonance apparatus and an operating method therefore, a data acquisition sequence for operating the apparatus is repeatedly reviewed in a number of ascertainment passes executed in a processor, each ascertainment pass involving a calculation step, and in each calculation step a determination is made as to other respective values of data elements used in a previous calculation step have changed. If no change has occurred, a re-calculation in the current calculation step is not implemented, thereby reducing the time and computing capacity that are needed to generate a final data acquisition sequence.

Abstract: Magnetic resonance tomography (MRT) local coil positioning by RFID is enabled with a positioning device to detect a position of a first object relative to a position of an additional object that includes at least one RFID tag arranged on the first object and/or at least one RFID reader arranged on the additional object.

Abstract: A method of magnetic resonance, in which a sample introduced in a measurement volume in an external magnetic field is excited by an excitation pulse and the signal formed by the transverse magnetization thus produced is read out by a receiving coil. The method is characterized in that a prewinding pulse is used as the excitation pulse, which prewinding pulse is characterized in that the formed transverse magnetization M?(?) of spins of different Larmor frequency ? after the pulse has a phase ?0(?), wherein ?0(?) as a function of ? within a predefined frequency range ?? has an approximately linear course having negative slope, such that the spins refocus after an echo time defined by the pulse without an additional refocusing pulse being necessary.

Abstract: A wireless power transmission system comprising a transmitting inverted Tesla Coil or Magnifier connected to the ground by its high voltage terminal using a capacitive earth connection and transmitting power through the ground to a subsequent receiving Tesla Coil or Magnifier being well earthed through a capacitive earth connection or conventional earth with the distance between the two earth connections of the transmitter and receiver plus the length of the coils in the transmitter and receiver forming a tuned length and the system thus composed being operated at a frequency that is an harmonic or close to an harmonic of the tuned length thus established.

Abstract: An apparatus for operation in a magnetic particle imaging mode for influencing and/or detecting magnetic particles in a field of view, and for operation in a magnetic resonance imaging mode, includes a selector having a selection field signal generator and selection field coils, a driver having a drive field signal generator and drive field coils for changing the position in space of the two sub-zones in the field of view by a magnetic drive field so that the magnetization of magnetic particles changes locally, and a focuser having a focus field signal generator and a focus field coil unit for changing the position in space of the field of view by a magnetic focus field.

Abstract: The present invention provides a nuclear magnetic resonance logging instrument probe with multi-layered magnet and an antenna excitation method, the nuclear magnetic resonance logging instrument probe includes a probe skeleton, multiple magnet assemblies and a plurality of antennas; the probe skeleton is of a cylindrical shape, multiple magnet assemblies are distributed in the circumferential direction of the probe skeleton; the magnet assembly includes at least two layers of magnet arranged from top to bottom, the magnet is magnetized in a radial direction, two adjacent layers of magnet are magnetized in opposite directions; an antenna is arranged outside each magnet assembly, multiple antennas are independently fed.

Abstract: A magnetic resonance imaging apparatus according to an embodiment includes a wireless communication unit, a radio frequency (RF) coil, and a specifying unit. The wireless communication unit includes an antenna and that transmits and receives a wireless signal through the antenna. The RF coil includes one or more antennas and that receives the wireless signal and to respond to the received wireless signal through the one or more antennas. The specifying unit that specifies the position and the orientation of the RF coil on the basis of a response result indicated by the response from the RF coil.

Abstract: An example pulse sequence for performing phase coherence order selection within a single transient acquisition includes an excitation pulse with a tip angle of 90° and phase ?A, followed by a train of N refocusing pulses with tip angles of 180°, with the center of the first refocusing pulse occurring time ? after the center of the excitation pulse, and the center of the nth refocusing pulse occurring at time (2n+1)? after the center of the excitation pulse. This causes a train of echoes to form at times 2nt after the center of the excitation pulse. In this example, the first refocusing pulse has phase ?B, where \?B??A\=90°, and each successive refocusing pulse (304) has a phase ?? greater than the last refocusing pulse. This incremental change in pulse phase over the course of the echo train has the effect of aiabatically “dragging” the echo phase around the unit circle in a predictable manner corresponding to the phase coherence order of the relevant signals.

Abstract: A method for estimating one or more properties as a function of depth of an earth formation penetrated by a borehole includes: receiving nuclear magnetic resonance (NMR) logging data having NMR echo trains as a function of depth in the borehole; receiving non-NMR logging data having non-NMR measurement values for one or more types of non-NMR measurements as a function of depth in the borehole; generating an evolution matrix (E) representing a mathematical relationship between the one or more properties in property matrix (P) to be estimated and the NMR logging data and non-NMR logging data matrix (M); generating a matrix equation of the form M=E·P; and inverting the matrix equation to estimate the one or more properties as a function of depth.

Abstract: A method and system for determining a nuclear magnetic resonance (NMR) property are described herein. The method includes applying a static magnetic field to a substance and applying an NMR pulse sequence to the substance. The NMR pulse sequence comprises a first pulse sequence segment applied at a first frequency to a shell and a second pulse sequence segment applied at a second frequency. The first pulse sequence segment generates a resonant signal in the shell and the second pulse sequence segment generates a characteristic within the resonant signal. The resonant signal is detected and an NMR property is determined using the characteristic within the detected resonant signal.

Abstract: A downhole tool, surface equipment, and/or remote equipment are utilized to obtain data associated with a subterranean hydrocarbon reservoir, fluid contained therein, and/or fluid obtained therefrom. At least one condition indicating that a density inversion exists in the fluid contained in the reservoir is identified from the data. Molecular sizes of fluid components contained within the reservoir are estimated from the data. A model of the density inversion is generated based on the data and molecular sizes. The density inversion model is utilized to estimate the density inversion amount and depth and time elapsed since the density inversion began to form within the reservoir. A model of a gravity-induced current of the density inversion is generated based on the data and the density inversion amount, depth, and elapsed time.

Abstract: A method to calibrate a nuclear magnetic resonance tool is disclosed having steps of starting a nuclear magnetic resonance sequence from the nuclear magnetic resonance tool, disabling an active damping circuit in the nuclear magnetic resonance tool, collecting auxiliary calibration data for the nuclear magnetic resonance tool, estimating a natural Q value for the nuclear magnetic resonance tool, determining an optimal active damping setting for the tool, deploying the optimal active damping setting for the tool, collecting nuclear magnetic resonance response data generated from the nuclear magnetic resonance sequence and calibrating the nuclear magnetic resonance data.

Abstract: A method of MR imaging a moving portion of a body includes detecting a motion signal from the body while continuously subjecting the moving portion of the body to one or more preparation RF pulses; subjecting the moving portion of the body to an imaging sequence including an excitation RF pulse and switched magnetic field gradients, wherein the imaging sequence is triggered by the detected motion signal; acquiring MR signals from the moving portion of the body; and reconstructing an MR image from the acquired MR signals.