Abstract: A wireline or logging while drilling device includes: a first coil configured to vary the intensity of a main magnetic field so as to produce phase modulation of signals emitted by spins in a sensitive volume; and a second coil configured to excite the spins in the sensitive volume in an inverse ratio of gyromagnetic constants of the spins; and receive signals from the spins displaced in frequency from the Larmor frequency of the spins by the phase modulation produced by the first coil.

Abstract: A wireline or logging while drilling device includes: a first coil configured to vary the intensity of a main magnetic field so as to produce phase modulation of signals emitted by spins in a sensitive volume; and a second coil configured to excite the spins in the sensitive volume in an inverse ratio of gyromagnetic constants of the spins; and receive signals from the spins displaced in frequency from the Larmor frequency of the spins by the phase modulation produced by the first coil.

Abstract: This disclosure provides systems, methods, and apparatus for measuring flow in and around a borehole of an earth formation. A flow measurement device can include a magnet configured to generate a static solenoidal magnetic field with a field intensity that decreases in strength peripherally from the magnet, an electromagnet disposed around the magnet and configured to generate a time varying solenoidal magnetic field, and a radio frequency (RF) coil disposed around the magnet and configured to generate an RF magnetic field transverse to the static solenoidal magnetic field. The flow measurement device can calculate a flow velocity in and around the flow measurement device based upon a signal received by the RF coil.

Abstract: Phase variations of the transverse magnetization in magnetic resonance induced by superimposed physical phenomenae or by intrinsic deviations of the main magnetic B0 field are separated from Feature Space set by demodulation and deconvolution, either by electrical circuits or by equivalent computational methods, permitting mapping and measurement of these induced phase variations independent of Feature Space.

Abstract: Phase variations of the transverse magnetization in magnetic resonance induced by superimposed physical phenomenae or by intrinsic deviations of the main magnetic B0 field are separated from Feature Space set by demodulation and deconvolution, either by electrical circuits or by equivalent computational methods, permitting mapping and measurement of these induced phase variations independent of Feature Space.

Abstract: Phase variations of the transverse magnetization in magnetic resonance induced by superimposed physical phenomenae or by intrinsic deviations of the main magnetic B0 field are separated from Feature Space set by demodulation and deconvolution, either by electrical circuits or by equivalent computational methods, permitting mapping and measurement of these induced phase variations independent of Feature Space.

Abstract: This disclosure provides systems, methods, and apparatus for measuring flow in and around a borehole of an earth formation. A flow measurement device can include a magnet configured to generate a static solenoidal magnetic field with a field intensity that decreases in strength peripherally from the magnet, an electromagnet disposed around the magnet and configured to generate a time varying solenoidal magnetic field, and a radio frequency (RF) coil disposed around the magnet and configured to generate an RF magnetic field transverse to the static solenoidal magnetic field. The flow measurement device can calculate a flow velocity in and around the flow measurement device based upon a signal received by the RF coil.

Abstract: A method of measurement of or mapping the distribution of complex permittivity, complex conductivity, complex impedance, or electric loss angle during magnetic resonance imaging or analysis. The method includes applying a time-varying electric field of a Faraday shield to a sample and cross-correlating the line spectrum signal so produced with the voltage applied to the Faraday shield in a detection circuit. The method permits non-contrast magnetic resonance screening for breast cancer in vivo and/or continuous measurement of electrical characteristics of materials at variable frequencies in vitro. A system of detecting and evaluating sample pathology includes a Faraday shield device that includes parallel electrodes oriented orthogonal to the static magnetic field of a MRI device to produce a time varying electric field. A detector is coupled to the MRI device to detect at least one of a complex permittivity, a complex conductivity, and an electrical impedance of the sample.

Abstract: Phase variations of the transverse magnetization in magnetic resonance induced by superimposed physical phenomenae or by intrinsic deviations of the main magnetic B0 field are separated from Feature Space set by demodulation and deconvolution, either by electrical circuits or by equivalent computational methods, permitting mapping and measurement of these induced phase variations independent of Feature Space.

Abstract: A method of measurement of or mapping the distribution of complex permittivity, complex conductivity, complex impedance, or electric loss angle during magnetic resonance imaging or analysis. The method includes applying a time-varying electric field of a Faraday shield to a sample and cross-correlating the line spectrum signal so produced with the voltage applied to the Faraday shield in a detection circuit. The method permits non-contrast magnetic resonance screening for breast cancer in vivo and/or continuous measurement of electrical characteristics of materials at variable frequencies in vitro. A system of detecting and evaluating sample pathology includes a Faraday shield device that includes parallel electrodes oriented orthogonal to the static magnetic field of a MRI device to produce a time varying electric field. A detector is coupled to the MRI device to detect at least one of a complex permittivity, a complex conductivity, and an electrical impedance of the sample.

Abstract: A method of measurement of or mapping the distribution of complex permittivity, complex conductivity, complex impedance, or electric loss angle during magnetic resonance imaging or analysis. The method includes applying a time-varying electric field of a Faraday shield to a sample and cross-correlating the line spectrum signal so produced with the voltage applied to the Faraday shield in a detection circuit. The method permits non-contrast magnetic resonance screening for breast cancer in vivo and/or continuous measurement of electrical characteristics of materials at variable frequencies in vitro. A system of detecting and evaluating sample pathology includes a Faraday shield device that includes parallel electrodes oriented orthogonal to the static magnetic field of a MRI device to produce a time varying electric field. A detector is coupled to the MRI device to detect at least one of a complex permittivity, a complex conductivity, and an electrical impedance of the sample.

Abstract: A method of measurement of or mapping the distribution of complex permittivity, complex conductivity, complex impedance, or electric loss angle during magnetic resonance imaging or analysis. The method includes applying a time-varying electric field of a Faraday shield to a sample and cross-correlating the line spectrum signal so produced with the voltage applied to the Faraday shield in a detection circuit. The method permits non-contrast magnetic resonance screening for breast cancer in vivo and/or continuous measurement of electrical characteristics of materials at variable frequencies in vitro. A system of detecting and evaluating sample pathology includes a Faraday shield device that includes parallel electrodes oriented orthogonal to the static magnetic field of a MRI device to produce a time varying electric field. A detector is coupled to the MRI device to detect at least one of a complex permittivity, a complex conductivity, and an electrical impedance of the sample.

Abstract: A method of measurement of or mapping the distribution of complex permittivity, complex conductivity, complex impedance, or electric loss angle during magnetic resonance imaging or analysis. The method includes applying a time-varying electric field of a Faraday shield to a sample and cross-correlating the line spectrum signal so produced with the voltage applied to the Faraday shield in a detection circuit. The method permits non-contrast magnetic resonance screening for breast cancer in vivo and/or continuous measurement of electrical characteristics of materials at variable frequencies in vitro. A system of detecting and evaluating sample pathology includes a Faraday shield device that includes parallel electrodes oriented orthogonal to the static magnetic field of a MRI device to produce a time varying electric field. A detector is coupled to the MRI device to detect at least one of a complex permittivity, a complex conductivity, and an electrical impedance of the sample.

Abstract: A method for determining petrophysical properties of geological structures using nuclear magnetic resonance utilizes a well logging apparatus and estimates resistivity in the formation surrounding a borehole by measuring current field strength and distribution.

Abstract: A simplified magnetic resonance flowmeter and flow measuring method, based on the dwell time of spins in the H1 Larmor radio frequency nutation field, which employs periodic H0 field gradients to phase modulate the spins so as to measure mean velocity of flow in near uniform velocity profiles or to map velocity of flow in non-uniform velocity profiles, which does not require pulse techniques and is relatively independent of relaxation and diffusion parameters consisting of a magnetizing section of pipe with a strong H0 magnetic field with a receiving section with orthogonal periodic phase modulating gradient coils, H1 Larmor radio frequency excitation (nutation) coils, and sideband receiver coils; utilizing a demodulating and cross-correlating receiver and a control system that permits concordant analysis of composition.

Abstract: A method for determining petrophysical properties of geological structures using nuclear magnetic resonance utilizes a well logging apparatus and estimates resistivity in the formation surrounding a borehole by measuring current field strength and distribution.

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: A method for determining petrophysical properties of geological structures using nuclear magnetic resonance utilizes a well logging apparatus and estimates resistivity in the formation surrounding a borehole by measuring current field strength and distribution.

Abstract: Weak oscillating gradients are used to modulate the angular momentum of the spins in a magnetic resonance imaging apparatus producing output signals in the receiver coil which can be synchronously demodulated to yield a periodic envelope containing integral harmonics of the oscillating gradient frequency. This periodic envelope is subjected to synchronous detection, continuously yielding the amplitudes of the individual harmonic components of the envelope which are then used to approximate an integral equation by a matrix solution to a linear transformation which generates the Radon transform of the transverse magnetization along the direction of the oscillating gradient, permitting image reconstruction. Truncation (Gibbs) artefacts are eliminated. Synchronous demodulation and synchronous detection of the impulse spectrum of the output signal from the receiver coil suppresses the continuous spectrum Johnson noise.

Abstract: An MRI apparatus comprises a magnet system producing a homogeneous magnetic field along the z axis. A plurality of wire conductors arranged in a "bird cage" configuration are supplied with a circularly rotating RF field centered near the Larmor frequency .omega..sub.o. The wire conductors receive a voltage source V.sub.p having a frequency .omega..sub.p, which is less than the Larmor frequency. The voltage source V.sub.p rotates about the wire conductors at a frequency of .omega..sub.s, which is much less than the frequency .omega..sub.p, to successively apply the voltage V.sub.p to each pair of diametrically opposed wire conductors in a manner which is ordered as a spatial cylindrical harmonic rotating at a frequency .omega..sub.s. The voltage source V.sub.p produces electric fields in the object which generate linear magnetic field gradients in the object. The voltage source V.sub.