Abstract: A steady-state condition for tipped nuclear spins is accelerated or catalyzed by first determining magnetization magnitude of the steady state and the scaling magnetization along one axis (Mz) to at least approximate the determined magnetization magnitude. Then the scaled magnetization is rotated to coincide with a real-valued eigenvector extension of the tipped steady-state magnetization. Any error vector will then decay to the steady-state condition without oscillation. In one embodiment, the magnetic resonance imaging utilizes steady-state free precession (SSFP). The scaling and rotating steps are followed by the steps of applying read-out magnetic gradients and detecting magnetic resonance signals from the tipped nuclear spins. The magnetization magnitude is determined by eigenvector analysis, and the eigenvector extension is a real-valued eigenvector determined in the analysis.

Abstract: An NMR (=nuclear magnetic resonance) probe head comprising an RF (=radio frequency) receiver coil system, which can be cooled down to cryogenic temperatures, and a room temperature pipe (4), extending in a z direction, for receiving a sample tube (6) containing sample substance (7) to be examined by NMR measurements is characterized in that at least one, preferably several radiation shields (9) extending in the z direction and surrounding the room temperature pipe (4) in a radial direction are disposed between the RF receiver coil system (1) and the room temperature pipe (4) which are formed of one or several materials oriented in the z direction and are almost completely transparent to RF fields, at least have an absorption of <5%, preferably <1% for RF fields to thereby provide simple and substantial reduction in the temperature gradient in the z direction during operation without thereby impairing the NMR measurement.

Abstract: A quantum computer comprises a crystal lattice having storage atoms. The storage atoms have nuclear storage spins, and quantum bits are stored as orientations of the storage spins. A magnetic field is applied to the crystal, the magnetic field having a gradient on the order of 1T/&mgr;m. The gradient is generated by a micromagnet. The electrons of the crystal acquire a regular order, and the storage spins are initialized by inducing combined electron-nucleus transitions in the crystal, thereby transferring the electronic order to the storage spins. The storage spins are decoupled from each other by a decoupling magnetic field. Quantum logic operations are performed on the storage spins. Certain quantum logic operations require a modification of the decoupling field to recouple a plurality of the storage spins. Final polarizations of the storage spins are measured.

Abstract: An NMR (=nuclear magnetic resonance) probe head comprising an RF (=radio frequency) receiver coil system, which can be cooled down to cryogenic temperatures, and a room temperature pipe (5), extending in a z direction, for receiving a sample tube containing sample substance to be examined by NMR measurements is characterized in that a temperature control (11) is disposed between the RF receiver coil system and the sample tube which surrounds the sample tube in a radial direction and extends in the z direction and is almost completely transparent to RF fields, or at least has an absorption of <5%, preferably <1% for RF fields to thereby provide simple and substantial reduction in the temperature gradient in the z direction during operation without thereby impairing the NMR measurement.

Abstract: The static magnetic field of a permanent magnet used in an NMR tool moves with the tool. NMR measurements made with a moving tool are affected by incomplete polarization of the nuclear spins in the region where the Larmor frequency of static field matches the RF signal frequency. Simulation results show that the in-phase and quadrature components of spin echo signals are affected by the velocity of lateral motion of a logging tool in a borehole. A phase drift indicator is obtained by summing the quadrature and in-phase components over a window and taking the ratio of the windowed sums. The phase drift indicator shows an increase with time. In a tool with a gradient magnetic field, the phase drift indicator increases with time even for no tool motion. The reduction in magnitude of spin echo data due to tool motion alone may be obtained by comparing the magnitude of simulated echoes with and without tool motion.

Abstract: A method and apparatus for protecting a sensor from impact and abrasion while drilling a borehole including a drill collar having a section of electrically non-conductive material, such as a composite material. The electrically non-conductive material has a rugged structural strength for conveying required drilling operation torque and load. The sensor which, for example, induces an RF field, is located inside the drill collar within the section of electrically non-conductive material wherein the sensor is protected from impact and abrasion while drilling a borehole without interference to the electromagnetic energy. The sensor is located, for example, within a load bearing section of the drill collar. Alternatively, the sensor is located inside a removable probe positioned inside the fluid channel through the drill collar. Stabilizers are used for stabilizing the probe within the channel.

Abstract: A nuclear decay laser that produces a stream of nuclear decay particles and/or photons of electromagnetic radiation. The stream of nuclear decay particles and/or photons is produced by subjecting radioactive materials to an external magnetic field which causes the radioactive nuclei to align with and precess around the external magnetic field vector. The precessing radioactive nuclei are then subjected to Radio Frequency (RF) pulses tuned to the Larmor frequency of the precessing nuclei which causes the nuclei to flip out of the plane of the external magnetic field vector into the X-Y plane. A refocusing RF pulse is then applied to the radioactive material which brings all of the magnetic moments of the flipped radioactive nuclei into phase. This can also be achieved with MRI gradient echo technology.

Abstract: By developing correlations between near-infrared spectra (NIR) and the T1 and T2 Nuclear Magnetic Resonance (NMR) decay times of known crude oils, we can then use near-infrared measurements to predict T1 and T2 decay times of unknown crude oils. The purpose is to use NIR to predict NMR parameters of crude oils while they are being sampled downhole by a formation tester and to use these predictions to improve log interpretation of NMR logs.

Abstract: Trapped field magnets (TFMS) on an NMR logging tool are used to produce a static magnetic field in a formation surrounding a borehole. The TFMs are made of material having a high Tc, so that the magnetic field can be sustained for the duration of the well logging by enclosing the TFMs within a cryostat containing liquid nitrogen as a coolant. By using the TFMs, the field strength within this region is much higher than is attainable with conventional magnets, giving an improved signal to noise (S/N) ratio for the NMR signals. The magnetic field strength within the TFMs is kept at a low enough value that instability problems associated with these materials do not arise. The field strength may be selected based upon knowledge of the resistivity and dielectric constant of the formation and the associated skin depth for electromagnetic signals. This makes it possible to use the TFMs in both wireline and measurement while drilling (MWD) environments.

Abstract: A method and apparatus for screening samples to determine which samples include a target material. Generally, the samples are pre-screened to determine which of the samples have a piezoelectric resonance when irradiated with an electric field, to thereby indicate the presence of the target material. The samples that have the piezoelectric resonance are then further screened by a different process to confirm the presence of the target material. For example, samples that have the piezoelectric resonance are further screened for a specific nuclear quadrupole resonance (NQR), a specific nuclear magnetic resonance (NMR) or a specific visual characteristic, to confirm the presence of the target material in the sample. The apparatus and method can be used, for example, to search luggage at ports of entry for the presence of cocaine hydrochloride or heroin hydrochloride.

Abstract: A method of operating a high-resolution NMR spectrometer comprising a DDS generator containing an NCOL for generating an LO frequency, wherein the frequency of the NCOL is defined by inputting a numerical value Z, is characterized in that this numerical value Z may assume only values which satisfy the equation Z=n·N/m, wherein Z, n, N, and m are integer and positive numbers, N is a power of 2 with a positive integer exponent, wherein said exponent represents the maximum number of bits during the calculation process, m is approximately 2·fs/&Dgr;B, n approximately m·fout/fs and m additionally a common integer divisor of n·N and fs is the clock frequency of the NCOL, &Dgr;B is the desired bandwidth with high spectral purity and fout is the output frequency of the NCOL.

Abstract: A method and apparatus is disclosed to initially screen a patient's peripheral arterial vasculature for lesions, or stenotic vessels, using MR technology, and then grading the severity of any located stenosis. The invention includes tracking the passage of a contrast agent bolus through a patient, while acquiring a series of first MR images having low resolution. This initial examination uses flow sensitive bi-polar gradient waveforms with a gradient echo imaging pulse sequence to increase the sensitivity to lesion detectability. The bi-polar gradients generate a broad distribution of velocities in a large voxel. Relevant stenoses present in a voxel will result in intra-voxel flow dephasing in voxels immediate to and distal to the stenosis. After identifying a stenosis, a second MR image, having a higher resolution than the first, is used to grade the stenosis.

Abstract: A magnetic resonance imaging (MRI) magnet in combination with a mobile patient-positioning device, including a patient support and a method of using same for positioning patients for MRI scanning. The patient support is rotatable through a range of orientations. The patient disposed on the patient-positioning device in a predetermined orientation can then be moved horizontally into and out of a patient-receiving space in the MRI magnet at the predetermined angle or orientation. A preferred embodiment includes a plurality of patient-positioning devices in which a series of patients can be placed in a ready state while one patient is within the patient-receiving space. As an alternative embodiment, the patient may be moved vertically into position for MRI scanning by way of an elevator which is actuatable from the floor below the patient receiving space. This elevator also may be used in combination with the patient-positioning device.

Abstract: A magnetic resonance imaging (MRI) system (100) performs optimized chemical-shift excitation. A computer system (110) performs a constrained numerical optimization to determine radio frequency (RF) pulse amplitudes, phase angles, and interpulse intervals for a binomial-like RF pulse sequence that will excite magnetization (41) of a selective one of two chemical species, such as water and fat for example, of a subject (102) in relatively less time and that may therefore be used at lower magnetic fields. A static magnet (132) produces a magnetic field along a predetermined axis relative to the subject Pulse sequence apparatus (134, 152, 154, 156, 158) creates magnetic field gradients with the magnetic field, applies RF pulsed magnetic fields, and receives resulting RF magnetic resonance (MR) signals. Pulse sequence control apparatus (142) controls the pulse sequence apparatus to apply the binomial-like RF pulse sequence to the subject.

Abstract: A method for determing the potential in a three-dimensional domain containing a source domain of source particles and a target domain of target particles involves assigning the source particles into source particle clusters and the target particles into target particle clusters, assigning a collection point to each of the clusters, and determing the inverse distance from each particle to the collection point of its respective cluster. A pseudo-particle representative of each particle within the cluster is defined at the collection point of each cluster in accordance with the determined inverse distances and the charge-like measure of each of the particles. The potential, and/or its gradient, at any of the target particles is then determined from the position and the charge-like measure of the associated pseudo-particle.

Abstract: In one embodiment of the invention, an induction logging system is used to measure selected formation and borehole parameters of interest and simultaneously provide indications of the quality of the selected measurements. One or more transmitter-receiver pairs are employed with the transmitter components operating at one or more frequencies. The induction logging system may be a conventional system with coil axes parallel to the borehole axis or may be a transverse induction logging system including coil axes inclined to the borehole axis. A model of the response characteristics of the borehole instrument is also employed. By using a subset of the measurements, the parameters of interest are determined and an expected value of the remaining measurements is made. A comparison of the actual and expected values of the remaining measurements serves as a quality control check on the equipment and on the accuracy of the model.

Abstract: An NMR logging tool includes at least one antenna and a pulse sequencer. The pulse sequencer is coupled to said at least one antenna and is adapted to receive state descriptors that are indicative of states of an NMR measurement sequence. The pulse sequencer uses the antenna(e) to perform the NMR measurement sequence downhole in a subterranean formation in response to the state descriptors.

Abstract: A method of measuring a strength of a capillary-porous chemically active material while hardening, the capillary-porous chemically active material including therein a liquid which undergoes metamorphosis and which is present in the capillary-porous chemically active material in different stages during curing, the method is effected by performing a high frequency, spin-echo nuclear magnetic resonance measurement of each stage of the liquid; and correlating the high frequency, spin-echo nuclear magnetic resonance measurement with a predetermined relationship between the strength and the high frequency, spin-echo nuclear magnetic resonance measurement.

Abstract: A magnetic resonance imaging device has a compensation circuit for compensating for magnetic disturbances therein. The compensation circuit includes a sensor for sensing magnetic field changes and generating a magnetic field change signal. The sensor is coupled to a control circuit that has a transfer function therein. The control circuit is used to generate a compensation signal in response to the magnetic field change signal. The compensation signal may be coupled to the compensation coils located by the first magnet portion and the second magnet portion of the device. Also, the compensation signal may produce a time-dependent bias or change the center frequency to cancel magnetic disturbances.

Abstract: A method and system for canceling extraneous signals in a nuclear quadrupole resonance (NQR) system used for the detection of explosives and drugs. A specimen is irradiated with a specific sequence of electromagnetic pulses, referred to as a spin-locked inversion mid-echo (SLIME) pulse sequence with each pulse having a specified phase and duration. The pulses are separated by specified time intervals. The SLIME pulse sequence has a single excitation pulse. As a result of the characteristics of the SLIME pulse sequence, if the target substance to be detected is present in the specimen, sets of oppositely-phased NQR echo signals are generated from the target substance. NQR echo signals of one phase are subtracted from NQR echo signals having the opposite phase, rendering a cumulative echo signal, and simultaneously subtracting out the same-phase extraneous signal.

Abstract: Nuclear magnetic resonance measurements of a porous medium using multiple wait times are used for determining the longitudinal relaxation time T1 time of oil in a hydrocarbon reservoir. The T1 values of water in the formation are represented by a distribution. In a dual wait time implementation of the method, data are acquired with a short wait time TWS chosen such that the wetting fluid phase (e.g., brine) is completely relaxed but the hydrocarbon phase is partially relaxed, giving a sequence ECHOA and with a long wait time TWL giving an echo sequence ECHOB. Using known methods, the T2 for the oil and water may be determined. The individual echo trains are summed and the T1 values determined from the summed echo trains and the determined values of T2. The summation greatly improves the SNR. An equivalent method determines the T1 values by summation of a first echo train that is the sum of the individual echo trains and the summation of a second echo train that is the difference of the individual echo trains.

Abstract: For the purpose of increasing the time available for performing a calculation on a navigator echo, a method comprises: during one of two consecutive periods TR, effecting RF excitation on spins within an object and acquiring a navigator echo, and thereafter effecting RF excitation for preparation; and during the other of the two consecutive periods, effecting RF excitation on the spins within the object and acquiring an imaging echo, and thereafter effecting RF excitation for preparation.

Abstract: NMR data are acquired using a phase-alternation of the tipping pulse. Differences between consecutive samples acquired with same or different frequencies are determined and an average value of the differences is determined over a sample window and over a range of echoes. This average value, determined separately for the in-phase and quadrature component data is a measure of the systematic noise and may be applied to the in-phase and quadrature component data to give corrected data with a higher resolution than prior art methods of processing phase alternated pulse sequence data. The method may also be used to improve the resolution of multifrequency NMR data acquired with a gradient logging tool.

Abstract: In a computer for evaluating signals from nuclear magnetic resonance tomography and a tomograph using such a computer, the neuronal activity measured during a nuclear magnetic resonance tomographic examination follows a protocol, which reproduces the temporal sequence of stimuli. During a correlation analysis, the sensitivity of known means to changes in the signal-response form normally decreases with each activation cycle. According to the invention, better evaluation results can be achieved in the correlation analysis by using a constant number of n data values in a correlation analysis employing a sliding-window technique. As the data measurement progresses, the oldest value is continuously disposed of and the most recent data value utilized in the calculation.

Abstract: An apparatus having an electromagnetic actuator for operating an actuating element, in particular an inlet or exhaust valve of an internal combustion engine, which includes an electromagnetic unit via which an armature which is mounted such that it may move and is operatively connected to the actuating element may be moved, and having a measurement apparatus which includes at least one inductive measurement element at least for detecting a position of the armature, and in particular having a spring mechanism which acts on the actuating element. At least one inductive measurement element may be firmly connected to the armature.

Abstract: The present invention relates generally to an apparatus and method for obtaining an azimuthally resolved nuclear magnetic resonance measurement of an earth formation traversed by a borehole. The measurement can be made while drilling or using a wireline tool. A receiving rf antenna having a non-axisymmetric response pattern is used to obtain the azimuthally resolved nuclear magnetic resonance measurement. The antenna employs axial currents which excite an azimuthally oriented rf magnetic field. For this situation, the static magnetic field is either radial or axial in its orientation. The antenna generates a relatively long, in axial extent, region of generally uniform static field magnitude and polarization in the formation. The present invention facilitates low profile antenna configurations that can permit dispensing with the reduction of the inner diameter of the drill collar at the rf antenna location.

Abstract: In magnetic resonance imaging apparatus having a resistive electromagnet with a bore 6, r.f. excitation pulse substantially simultaneously excites a number of slices A to D which are phase encoded and frequency encoded in the usual way, the direction of the main field being along the bore of the electromagnet in the direction z. The receive coil consists of an array of coils 5a to 5d which view different spatial regions of the imaging volume and the outputs of which are combined in different ways in order to reduce the number of slice encoding steps in the z-direction needed to distinguish between the slices A to D. Each coil of the array 5a etc. can form part of a two dimensional array in order to reduce the number of phase encoding steps in the phase encode direction.

Abstract: A novel method and apparatus is disclosed for the separation of fluid phases in NMR borehole measurements. The method is based on selecting an optimum contrast mechanism and a corresponding set of measurement parameters for a particular borehole environment. The contrast mechanism can be based on diffusion, relaxation time or hydrogen index differences between different types of fluids. Once an initial measurement is made, the measurement parameters are compared to a predetermined set of values to broadly estimate the types of fluids present in the geologic environment. If necessary, the measurement is repeated to obtain optimal fluid typing for the estimated fluid types.

Abstract: A method for enhancing measurement resolution is disclosed. In one embodiment, the method includes (1) obtaining multiple measurement samples at each of multiple positions along a borehole; (2) extracting reference index samples from the set of measurement samples; (3) determining a difference between each of the reference index samples and corresponding modeled index samples; and (4) updating a set of enhanced index samples based on the difference. The index samples are preferably chosen to be representative of the measurement samples obtained at each position, and accordingly, may be selected ones of the measurement samples, or alternatively, may be averages of the measurement samples. The aforementioned modeled index samples may be found from application of a predetermined tool response to the enhanced index samples, which in turn, may be found by iteration.

Abstract: The present invention relates generally to an apparatus and method for obtaining an azimuthally resolved nuclear magnetic resonance measurement of an earth formation traversed by a borehole. The measurement can be made while drilling or using a wireline tool. A receiving rf antenna having a non-axisymmetric response pattern is used to obtain the azimuthally resolved nuclear magnetic resonance measurement. The antenna employs axial currents which excite an azimuthally oriented rf magnetic field. For this situation, the static magnetic field is either radial or axial in its orientation. The antenna generates a relatively long, in axial extent, region of generally uniform static field magnitude and polarization in the formation. The present invention facilitates low profile antenna configurations that can permit dispensing with the reduction of the inner diameter of the drill collar at the rf antenna location.

Abstract: An NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled.

Abstract: The present invention provides a pressure cell for pressurizing materials for use in NMR spectroscopy, comprising a sample tube made of sapphire for placing the material, the tube being closed at one end, a housing for holding the sample tube such that the material in the tube can be pressurized, a cove for closing the housing, the cover having an inlet for pressuring the material, means for sealing the cover to the housing, and means of sealing the housing to the sample tube.

Abstract: Methods for increasing the imaging accuracy of object density pixel values by forming linear combinations thereof to counteract spatial mixing of object density pixel value information, and by using an estimate of the object density pixel values to correct for the effects of variations in the object density. A measured variable M as a function of time t is related to the actual object density by M(t)=∫F((q),q,t) (q) dq, where q is the spatial variable. An estimated object density * is related to an actual object density by (q)=∫&Sgr;tE([],q,t)F(,q′,t) (q′) dq′, where E is an approximate inverse of F, and &Sgr;tE([],q,t)F(,q′,t) is defined as the kernel function A(q,q′). Due to the limited number of time samples, the kernel A only approximates the delta function &dgr;(q−q′), and values of (q′) away from q=q′ contribute to *(q).

Abstract: A side-looking NMR logging tool incorporates a permanent magnet arrangement having a magnetization direction oriented towards a side of the tool and a dipole RF antenna displaced towards the front of the tool. The magnet arrangement produces a shaped region of investigation in front of the tool wherein the magnetic field has a uniform field strength and the RF field has a uniform field strength in a direction orthogonal to the static field. The shaping of the static field is accomplished by the magnet arrangement comprising a plurality of magnets having parallel magnetization or by a single shaped magnet. The antenna arrangement includes a gapped core made of non-ferritic soft material for increasing the antenna efficiency. The magnet arrangement also reduces ringing in the core and the antenna. An optional RF shield is used to reduce NMR signals from borehole fluids.

Abstract: A method for determining nuclear magnetic resonance longitudinal relaxation time of a medium. The method includes magnetically polarizing nuclei in the medium along a static magnetic field, momentarily inverting the magnetic polarization of the nuclei within each one of a plurality of different spatial volumes within the medium, transversely magnetizing the nuclei in each one of the spatial volumes after an individual recovery time corresponding to each one of the spatial volumes, and measuring an amplitude of a magnetic resonance signal from each one of the spatial volumes.

Abstract: There is provided a method and apparatus for determining resistivity in a formation surrounding a borehole. In one embodiment, the apparatus includes a magnetic resonance well logging tool disposed on said borehole, the magnetic resonance well logging tool producing a magnetic resonance sensitive volume thereabout, and a detector that selectively measures current flow in the formation both perpendicular to and parallel to the borehole axis within and adjacent to the sensitive volume.

Abstract: In a method for the operation of a magnetic resonance apparatus, in a first examination of an examination subject, a first scout dataset of the examination subject is produced and with reference to which at least one first slice of an examination subject to be imaged is determined. A further scout dataset of the examination subject is produced in at least one further examination of the examination subject temporally following the first examination. A change in position between the first and the further scout dataset is identified, and at least one further slice of the examination subject to be imaged is defined according to the identified positional change, this at least one further slice exhibiting an identical positioning within the examination subject with respect to the first slice.

Abstract: An interpretation method and system for NMR echo-train data in thinly laminated sequences. The invention uses geological information obtained at higher vertical resolution, such as using Electric Micro Imaging, to enhance the vertical resolution of echo-train data, and thus avoids log interpretations in which the hydrocarbon potential of the formation can be misread because low resolution logs tend to provide an average description of the formation. Such averaging is especially problematic in thinly laminated sequences that consist of highly permeable and porous sand layers and less permeable silt or essentially impermeable shale layers. In a preferred embodiment, using the additional high-resolution formation information one can estimate the typical T2-spectra of lithological laminae, and significantly enhance the permeability estimate in the laminated sequences.

Abstract: Increasing RF transmission power, retuning the RF transmitter and receiver coils, and increasing RF reception gain, enable MR inspection of product in a container that presents a substantial portion of an electrically conductive barrier in transverse orientation to the exciting RF magnetic field.

Abstract: A nuclear decay laser that produces a stream of nuclear decay particles and/or photons of electromagnetic radiation. The stream of nuclear decay particles and/or photons is produced by subjecting radioactive materials to an external magnetic field which causes the radioactive nuclei to align with and precess around the external magnetic field vector. The precessing radioactive nuclei are then subjected to Radio Frequency (RF) pulses tuned to the Larmor frequency of the precessing nuclei which causes the nuclei to flip out of the plane of the external magnetic field vector into the X-Y plane. A refocusing RF pulse is then applied to the radioactive material which brings all of the magnetic moments of the flipped radioactive nuclei into phase. This can also be achieved with MRI gradient echo technology.

Abstract: An MRI image is corrected for motion artifacts using an iterative, autocorrection process in which corrections are tried and the quality of the resulting reconstructed image is measured. Metrics based on the gradient of the reconstructed image are employed to measure image quality.

Abstract: An NMR logging apparatus and method are provided including an antenna having compensation for magnetostrictive ringing. The antenna comprises at least one inductive winding and a core having a first portion having positive magnetostriction in the presence of a radio frequency magnetic field, and a second portion having negative magnetostriction in the presence of the radio frequency magnetic field. The positive and negative portions may be tiles shaped as polygonal cylinders arranged with alternating positive and negative tiles forming at least one layer of a matrix, or the portions may be constructed using ferrite powder fixed in epoxy and shaped in polygonal cylinders.

Abstract: A magnetometer for, among other things, measuring a magnetic field, associated with nuclear magnetic spins or electron spins receives a specimen of a material that exhibits nuclear magnetic resonance or electron spin resonance at a resonant frequency &ggr;·Bm that is dependent on a magnetic flux density Bm of the magnetic field to be measured. The magnetometer has a transmission device for emitting a transmission signal into the specimen at at least one prescribable transmission frequency &ohgr;1 that has a frequency spacing from the resonant frequency &ggr;·Bm, and a reception device for receiving a mixed signal with mixed frequencies containing the resonant frequency &ggr;·Bm and the transmission frequency &ohgr;1 and for filtering out the resonant frequency &ggr;·Bm from at least one of the mixed frequencies as an indicator for the magnetic flux density Bm.

Abstract: A polarimetric sensor includes a sensor unit constructed as a permanently assembled unit having a polarizer, a sensor element and an analyzer. An input optical waveguide and an output optical waveguide with a core diameter of at least 100 &mgr;m are provided. A first light signal emerging from the input optical waveguide passes directly through the sensor unit and enters the output optical waveguide as a second light signal. An optical path of the first light signal through the sensor element is no longer than 50 times the core diameter of the output optical waveguide. No separate focussing or collimation optics are provided.

Abstract: A contact probe for carrying out an electric test by being brought into contact with respective terminals of a liquid crystal display device and a liquid crystal display testing device utilizing such a contact probe. The contact probe has a structure which may include a metal film attached to a nonconductive resin film, which prevents intervals between contact pins from being changed, for example based on changes in humidity. A nonconductive resin film may also be attached on the metal film. An elastic film may also be attached to a nonconductive resin film to ensure a proper orientation of contact pins in a testing operation. The liquid crystal display testing device can utilize such contact probes.

Abstract: A device for measuring components of a magnetic field includes a scalar magnetometer surrounded by at least two conductor windings supplied continuously with currents from different generators. A processing circuit demodulates the signal supplied by the scalar magnetometer and supplies signals corresponding to the components of the field to be measured along the axes of the conductor windings.

Abstract: A magnetic resonance imaging apparatus has a device for measuring magnetic field strengths including a light source that emits linearly polarized light, a Faraday cell that contains magneto-optically active material and that has at least one light outputs, the linearly polarized light emitted by the light source entering into the Faraday cell and traversing a prescribable number of optical path lengths therein and subsequently emerging via the corresponding light output. The device further has an analyzer for the linearly polarized light emerging from the Faraday cell, with the polarization plane of the analyzer being adjusted by a prescribable rotational angle relative to the polarization plane of the linearly polarized light emerging from the light source, and a light sensor that acquires the light emerging from the analyzer.

Abstract: A fast, spectrally-selective steady-state free precession (SSFP) imaging method is presented. Combining k-space data from SSFP sequences with certain phase schedules of radiofrequency excitation pulses permits manipulation of the spectral selectivity of the image. For example, lipid and water can be rapidly resolved. The contrast of each image depends on both T1 and T2, and the relative contribution of the two relaxation mechanisms to image contrast can be controlled by adjusting the flip angle. Several applications of the technique are presented, including fast musculoskeletal imaging, brain imaging, and angiography. The technique is referred to herein as linear combination steady-state free precession (LCSSFP) and fluctuating equilibrium magnetic resonance (FEMR).

Abstract: The invention relates to a process to examine at least one object, whereby properties of the object are detected at different times within a spatial-frequency space formed by spacial-frequencies.

Abstract: A magnetic resonance imaging apparatus generates an MR signal from an object to be examined by applying a gradient field pulse generated by a gradient field coil and a high-frequency magnetic field pulse generated by a high-frequency coil onto the object in a static field generated by a static field magnet, and reconstructs an image on the basis of the MR signal. The gradient field coil is housed in a sealed vessel. A cable extending from an external power supply and connected to the gradient field coil has predetermined flexibility.