154results about "Susceptibility measurements" patented technology

A probe instrument using room-temperature sensor(s) that can measure variations in magnetic susceptibilities. The instrument has sufficient resolution to monitor paramagnetic materials in a human body, such as iron in a human liver, by noninvasively examining patients with iron-overload diseases. The instrument includes room temperature magnetic sensors, and detects the sample, that is, the tissue response to an alternating current field applied by an applied field coil. The applied field coil dimensions are chosen so that the applied field is optimized for maximum response from the liver while minimizing the effects due to the overlying abdominal tissue and at the same time not unduly increasing the sensitivity of the instrument to the lung. To overcome variations in the sensor output due to fluctuations in the applied field, change in the ambient temperature and mechanical relaxation of the instrument, the sensor-sample distance is modulated. The detector assembly is oscillated while the examined patient remains stationary. An improved water-bag technique is employed to eliminate background tissue response. The detector assembly forms part of a probe instrument for performing noninvasively the paramagnetic concentration of a patient.

The present invention relates to method and device for detecting changes of a magnetic response of at least one magnetic particle in a carrier fluid. The method comprises: using a measuring procedure comprising measuring the characteristic rotation time of said magnetic particle, said measuring procedure further involving measuring Brownian relaxation in said carrier fluid under influence of an external pulsed excitation magnetic field, and based on said influence of said external pulsed excitation magnetic field measuring a hydrodynamic volume of a particle or a change in a hydrodynamic volume of the particle change upon modification of an effective volume of the particle or its interaction with said carrier fluid by detecting change of magnetization of the particle with time by monitoring change of an output signal in detection coil.

The invention provides a magnetic sensor device which can enlarge the detection range in a medium width direction which is orthogonal to a medium moving direction. In a sensor magnetic core of a magnetic sensor component, a plurality of magnetic matrix protruding parts (431, 432) which protrudes from a main body extending in a width direction W40 to one side of a medium moving path are mutually separated in a width direction W40. The plurality of magnetic matrix protruding parts are reeled with detection coils (491, 492), and the main body is reeled with an excitation coil. The magnetic sensor component is configured in that a thickness direction T40 which is orthogonal to the width direction W40 and the protruding direction of the magnetic matrix protruding parts (height direction V40) faces towards the moving direction X of the medium. The magnetic matrix protruding parts and the detection coils are disposed at a division position of a medium width direction Y which is orthogonal to the medium moving direction.

Systems and methods are provided for remotely identifying and classifying materials based on their respective complex permittivity features. Materials of interest to be identified in later inspections are cataloged according to their respective complex permittivity features by applying electromagnetic fields to them and determining their complex permittivity features. That library of features is used to compare field measurements taken during an inspection to determine the presence of a material of interest and to identify it.

An on line test method and test system of differential type temperature-compensating bridge rope force based on the magnetoelasticity is disclosed. The bridge rope is the ferromagnetic material and placed in the specific magnetic field, the bridge rope will be magnetized; the magnetic conductivity of bridge rope will change with the variety of stress condition and temperature. The sensor comprises operating magnetic circuit and reference magnetic circuit, in every designing of the magnetic circuit, the bridge rope is just a part of the magnetic circuit and not as the iron core of the actuating coil and the measuring coil. The reference magnetic circuit of sensor just feels the changes of temperature, but the operating magnetic circuit feels the changes of temperature and rope force, the output signal of the operating magnetic circuit and the reference magnetic circuit is differential to eliminate the temperature effect, the value of rope force can be tested with the corresponding relationship between the change of magnetic conductivity and rope force. The test method of rope force in the invention characterized in high accuracy, well dynamic response, low price of sensor, convenience of mounting and conditioning, long service life, strong overcurrent protection power, fitting for static and dynamic measurement, sampling just in time in all-weather, the testing results are free of effects of anticorrosive coating and protective plastic casing which is in surface of bridge.

Contrast agents incorporating super-paramagnetic iron-oxide (SPIO) nanoparticles have shown promise as a means to visualize labeled cells using MRI. Labeled cells cause significant signal dephasing due to the magnetic field inhomogeneity induced in water molecules near the cell. With the resulting signal void as the means for detection, the particles are behaving as a negative contrast agent, which can suffer from partial-volume effects. Disclosed is a new method for imaging labeled cells with positive contrast. Spectrally-selective RF pulses are used to excite and refocus the off-resonance water surrounding the labeled cells so that only the fluid and tissue immediately adjacent to the labeled cells are visible in the image. Phantom, in vitro, and in vivo experiments show the feasibility of the new method. A significant linear correlation (r=0.87, p<0.005) between the estimated number of cells and the signal has been observed.

A device and method for determining the state of charge of an object, such as an electrochemical battery cell. The device includes a state of charge sensor having a primary magnet that creates a primary magnetic field, and at least one magnetic field sensing element. The sensitivity axes of the sensing elements are substantially perpendicular to the direction of polarization of the primary magnet. The primary magnet and the sensing elements are placed in the proximity of the object, and magnetic fields resulting from the magnetic susceptibility of the object are measured by the sensing elements. The sensing elements output an electrical signal from which the state of charge of the object can be determined.

A measuring device consists of closed-loop soft magnetic material and magnetization coil and detecing coil wound on it; magnetization loop connected in series by magnetization coil, sampling resistance, variable resistance and adjustable DC power supply controlled with communication switch or relay as well as measuring loop formed by detecting coil and electronic integrator. The two ends of sampling resistance and output end of electronic integrator are connected to signal handling module and analog-digital conversion circuit as the converter digital signal is connected to computer through computer parallel interface or interface card.

A magnetomechanical gas analyzer such a paramagnetic oxygen analyzer which has a dumbbell which is rotatably suspended in the region of action of an inhomogeneous magnetic field and around which a gas to be measured flows. The dumbbell is connected, fixed in rotation, to a mirror for deflecting a light beam. In order to damp in the analyzer all kinds of oscillations which have a negative effect on stability in the balance point, and to increase the detectability and the speed of the measurement, there are least two electrically conductive surface segments which are essentially perpendicular to one another are arranged for eddy-current damping on the dumbbell or in the mechanical gearing on the dumbbell and in the region of action of the inhomogeneous magnetic field. One of the surface segments may be the mirror.

To provide a magnetic body detector as a means for warning that a magnetic body enters into a room where a strong magnet, such as an MRI diagnostic system, is installed, whereina magnetic sensor can detect even a small magnetic body without being saturated even in an environment with strong magnetic flux density; andappropriate notification is provided to a user by arithmetic processing for inhibiting the detected value of a magnetic body that does not pass through a gate.[Means for Solving the Problem]By adjusting a solid angle formed with a detection axis of the magnetic sensor and a vertical axis or a horizontal axis to be within 15 degrees, a strong direct-current magnetic flux density to be applied to the detection axis is reduced;a small change in magnetic flux density due to the entry of a small magnetic body is detectable without saturation;the characteristics of a magnetic body that will not pass through the gate is extracted by the magnetic sensors arranged in the front, rear, left and right of the gate; andonly a magnetic body in the vicinity that passes through the gate is regarded as a target for detection by inhibiting magnetic bodies that will not pass through the gate by calculation.

The invention discloses a measuring device and a measuring method of superconductive AC magnetic susceptibility, belonging to the field of superconducting electronics. The measuring method comprises the steps of: positioning a measured superconducting material between a primary coil and a secondary coil, and fixing the elements in a sealed vacuum chamber, refrigerating the measured superconducting material via a compression refrigeration machine, extracting a voltage signal induced by the secondary coil through a phase-locking amplifier, and simultaneously providing AC voltage excitation to the primary coil through the phase-locking amplifier, measuring the temperature of the measured superconducting material through a temperature controller, storing the voltage signal measured by the phase-locking amplifier and a temperature signal measured by the temperature controller in a computer, and displaying the temperatiredependent curve of the voltage signal measured by the phase-locking amplifier in real time. The measuring method of the invention has the advantages of performing a nondestructive measurement on the conversion temperature of the superconducting material to conveniently master the measurement condition in time, and the measuring method is an efficient, accurate and reliable measurement manner, so that the measuring method has certain practical value for detecting the performance of the superconducting material.

Contrast agents incorporating super-paramagnetic iron-oxide (SPIO) nanoparticles have shown promise as a means to visualize labeled cells using MRI. Labeled cells cause significant signal dephasing due to the magnetic field inhomogeneity induced in water molecules near the cell. With the resulting signal void as the means for detection, the particles are behaving as a negative contrast agent, which can suffer from partial-volume effects. Disclosed is a new method for imaging labeled cells with positive contrast. Spectrally-selective RF pulses are used to excite and refocus the off-resonance water surrounding the labeled cells so that only the fluid and tissue immediately adjacent to the labeled cells are visible in the image. Phantom, in vitro, and in vivo experiments show the feasibility of the new method. A significant linear correlation (r=0.87, p<0.005) between the estimated number of cells and the signal has been observed.

A method to detect a decrease of the demagnetization of permanent magnets of the generator of a wind turbine, wherein a frequency converter is able to adapt to the variable frequency of the generator output voltage to the frequency of a power grid, wherein the AC / DC converter or the DC / AC converter of the frequency converter is been disabled, the electrical connections between the generator and the frequency converter are switched on via circuit breakers, the generator speed is determined; the generator output voltage is determined by a voltage sensor which is part of the frequency converter,the magnetic flux density of the generator is calculated depending on the generator speed and the generator output voltage, a demagnetization event is determined by comparing the resulting flux density value with a predetermined flux density value is provided.

An ultra-sensitive SQUID-based magnetoreduction measurement system for performing an assay is provided, wherein the system is capable of measuring the concentration of multiple-active-epitope biomolecules, single-active-epitope biomolecules, or small biomolecules with high sensitivity. The sensitivity of the ultra-sensitive magnetoreduction measurement system is 1 ppt or below. The system includes a sample unit and a sensor unit. The sample unit includes excitation coils and a pick up coil, and a sample housed inside the pick up coil, wherein the sample contains at least magnetic nanoparticles coated with bio-receptors that are conjugated with to-be-detected biomolecules. The sensor unit includes a SQUID magnetometer and a couple coil, wherein the magnetization of the sample sensed by the pick-up coil is transferred to the magnetometer at the sensor unit via the couple coil.

An apparatus for the measurement of the magnetic susceptibility of a gas mixture comprises: a gas sample chamber (8) adapted to receive the gas mixture, and a test body (1) rotatably suspended within the gas sample chamber; means (10) for creating an inhomogeneous magnetic field within the gas sample chamber; means for detecting rotational motion of the test (body 1), comprising a compact optical system including a light source (12) and photodetectors (13) arranged to detect a light signal indicative of the rotational motion; and an actuation system (4) arranged to keep the test body (1) substantially at a null position determined by said optical system, wherein the optical system comprises at least one photodetector (13) positioned on either side of the plane which is normal to the mirror and parallel with the rotation axis of the test body, having the light source (12) positioned in the plane. For enhanced performance, an optical element (16) is placed in front of the light source or photodetectors to modify properties of the light emitted by the light source or received by the photodetectors.

The invention relates to a plane measurement method and an apparatus for a total field magnetometer measuring rock and a magnetic parameter of ore specimen. The employed plane measurement apparatus comprises a total field magnetometer, a specimen box with specimen in the box, a flat and flat supports. The total field magnetometer includes probes and probe supports. According to the invention, parameters measured by the total field magnetometer are inserted into formulas so as to obtain a magnetic susceptibility K and a residual magnetization Mr of specimen parameters. According to an appendix C of Technical Regulations on Ground High-precision Magnetic Survey in China, an apparatus of the total field magnetometer measuring rock and the magnetic parameter of the ore specimen is an oblique measurement apparatus. According to the invention, the oblique measurement is modified into plane measurement. Therefore, with utilization of the plane measurement apparatus, errors caused by inaccurate slope adjustment can be avoided. Moreover, with utilization of the oblique measurement apparatus, the rock and ore specimens are overturned and vibrated on the oblique surface, so that inclined displacement is caused and thus a maximum error of deviation in range is caused; however, the above-mentioned problem can be solved according to the invention. the plane measurement apparatus provided in the invention has advantages of simple structure and firmness; besides, the precision of the magnetic parameter measurement of the rock and ore specimens can be improved.

The invention relates to a magnetic material processing device capable of reaching 1600 DEG C. A water cooling machine is connected with a compressor; the compressor is connected with the input end and the output end of a liquid nitrogen cooling nozzle of a superconducting magnet; an excitation power supply is connected with the superconducting magnet; the lower end of a quartz tube passes througha copper bush, and is arranged in a heating body; the upper end of a thermocouple passes through a thermocouple fixing plate, and is arranged in the heating body; the heating body is positioned in athermal insulation layer; the thermal insulation layer is positioned in a water cooling layer; the water cooling layer is positioned in the superconducting magnet; an infrared probe, a test tube clampand a balance form a balance magnetic susceptibility measurement system; and the infrared probe and the balance are connected with a computer through a conducting wire and a conversion interface. Themagnetic material processing device capable of reaching 1600 DEG C disclosed by the invention is simple in structure, convenient to use and operate, and easy to disassemble; the cavity space of the superconducting magnet is large; furthermore, the reachable magnetic field intensity is high; therefore, the range increasing size of processed materials can be increased; the size of a contained sample is convenient for later testing of various performances; and thus, experiment and test analysis integration can be realized.

A device for measuring alternating current (AC) magnetic susceptibility and the method for measuring the same are provided. The device comprises an AC magnetic susceptibility coil set, a signal capturing unit, and a signal processing unit. The device detects AC magnetic susceptibility signals from under testing particles in the magnetic field with variable AC frequencies, and extracts the AC magnetic susceptibility intensity variation and phase difference and / or the real part and the imaginary part of the AC magnetic susceptibility by the signal processing unit.

The invention relates to a method for measuring the magnetic permeability of a magnetic material by measuring the magnetic interaction of an electromagnetic field with this material by using a measuring device including a measuring cell connected through a microwave frequency cable (13) to a vector network analyser (12), said method comprising steps for gauging / calibrating said measuring device, for determining corrective coefficients to be applied to the measurements obtained by means of this device, for verifying the non-drift of this device, these steps being carried out with the help of a reference sample, wherein a reference sample is used, comprising at least one inclusion which enables creation, in a given volume, of a local artificial permeability, each inclusion being achieved by combining at least one inductive component possibly associated with a combination of at last one capacitive and / or resistive and / or active component, the frequency response of the electromagnetic properties of each volume being adjusted by the value and the assembly architecture of the components.The invention also relates to such a reference sample.

A method and apparatus for determining volume and anisotropy field distribution of thin film granular material includes the use of a magneto-optic probe, a lock-in amplifier, and a computer. The magneto-optic probe utilizes the Kerr effect in order to determine the transverse AC susceptibility of the sample. The Lock-in amplifier determines the complex parameters of the susceptibility as a function of the DC field and AC frequency. Separate distribution values of anisotropy field and grain volume can then be determined mathematically from the relationship of complex susceptibility parameters to the DC field strength.

A micro-electrochemical sensor contains magnetic compounds inserted within a substrate that exert a magnetic force of attraction on paramagnetic beads held in contact with an electrode. The magnetic compounds can be contained within a fluid that is introduced into a void in the substrate. The electrode can be spaced apart from the magnetic compounds by a dielectric multi-layer membrane. During the fabrication process, different layers within the membrane-electrode structure can be tuned to have compressive or tensile stress so as to maintain structural integrity of the membrane, which is thin compared with the size of the void beneath it. During a process of forming the structure of the sensor, the tensile stress in a TiW adhesion layer can be adjusted to offset a composite net compressive stress associated with the dielectric layers of the membrane. The membrane can also be used in forming both the electrode and the void.

A system and method for estimating the state-of-charge (SOC) of a battery cell in a vehicle using a magnetic sensor that measures changes in magnetism of the battery cell. The method provides an offset correction to a current output signal from the magnetic sensor that calibrates the current output signal to a known magnetic field strength, provides a temperature correction to the current output signal that corrects the current output signal based on a temperature of the magnetic sensor, and provides a current correction to the current output signal that removes portions of the magnetic field caused by other battery cells, where the corrected current output signal is converted to the battery cell SOC.

The invention provides a magnetic susceptibility measuring device based on magneto-Archimedes levitation. The device comprises a magnetic field generating device, a measuring container, a magnetic field regulating device and a remote observing system, wherein the measuring container is placed in the magnetic field generating device, the magnetic field generating device comprises an upper support, a lower support, a first electromagnet and a second electromagnet, the upper support and the lower support are fixed through four screws matched with nuts, the first electromagnet is placed in the hollow portion of the upper support, the second electromagnet is placed in the hollow portion of the lower support, the same magnetic poles of the first electromagnet and the second electromagnet are opposite, the first electromagnet and the second electromagnet are connected in parallel and then connected with the magnetic field regulating device in series, and the remote observing system comprises a camera and a computer. According to the magnetic susceptibility measuring device based on magneto-Archimedes levitation, magnetic induction intensity can be effectively controlled through the magnetic field regulating device, and then a wider magnetic susceptibility measurement range is realized; the distance between the two electromagnets can be adjusted as needed during measurement, measuring span is enlarged, and the flexibility of the device is improved greatly.

A permeability measurement apparatus includes a magnetic field generation means applying an alternating magnetic field having a predetermined frequency to a magnetic substance to be measured; a probe needle placed in proximity or in contact to a microscopic area of the magnetic substance to be measured to which the alternating magnetic field is applied; a resonator including a coil wound on the probe needle, and generating a magnetic field having a resonant frequency higher than the frequency of the alternating magnetic field applied on the microscopic area having the probe needle in proximity or in contact thereto, and having an inductance of the coil varied as permeability in the microscopic area varies; and a measurement means measuring the permeability of the microscopic area of the magnetic substance to be measured based on the variation of the resonant frequency of the resonator according to the variation of the coil inductance.

Methods and apparatus for minimizing the effects of temperature drift in a magnetic susceptibility measurement instrument, such as an instrument used in pre-MRI screening for the presence of ferromagnetic foreign bodies. The magnetic field source and magnetic sensors can be combined into a single, rigid unit. The stability and sensitivity required in high quality magnetic susceptibility measurements can be achieved through symmetrical design of the source-sensor unit, minimization of thermal stresses, minimization of temperature variations, use of materials with low thermal expansion coefficients, or through appropriate combinations thereof. Use of patient eye movement where an eye is being screened, use of a water bag between the patient and the instrument, or use of telemedicine to facilitate performance of the necessary computations can also be incorporated.

The present invention relates to a microfluidic chip for measuring the magnetic susceptibility of a superparamagnetic nanoparticle droplet and a method for measuring magnetic susceptibility using the same. According to the invention, the magnetic susceptibility of a superparamagnetic nanoparticle can be continuously and accurately measured in a flowing fluid using a microfluidic chip including microfluidic channels.