3075 results about "Magnetic field magnitude" patented technology

A method and apparatus for collecting and processing physical space data used while performing image-guided surgery is disclosed. Physical space data is collected by probing physical surface points of surgically exposed tissue. The physical space data provides three-dimensional (3-D) coordinates for each of the physical surface points. Based on the physical space data collected, point-based registrations used to indicate surgical position in both image space and physical space are determined. In one embodiment, the surface of surgically exposed tissue of a living patient is illuminated with laser light. Light reflected from the illuminated surface of the exposed tissue is received and analyzed. In another embodiment, one or more magnetic fields of known shape and size are established in the proximity of the exposed tissue. Data associated with the strength of the magnetic fields is acquired and analyzed.

A combination MRI and radiotherapy system comprising: a) an MRI system for imaging a patient receiving radiotherapy, comprising a magnetic field source suitable for generating a magnetic field of strength and uniformity useable for imaging, capable of being ramped up to said magnetic field in less than 10 minutes, and ramped down from said magnetic field in less than 10 minutes; b) a radiation source configured for applying radiotherapy; and c) a controller which ramps the magnetic field source down to less than 20% of said magnetic field strength when the radiation source is to be used for radiotherapy, and ramps the magnetic field source up to said magnetic field strength when the MRI system is to be used for imaging.

A noise pattern acquisition device includes: a geomagnetic sensor; a coordinate estimation unit configured to estimate current position coordinates; and a geomagnetic noise pattern management unit configured to, when an abnormality occurs in a magnetic field strength detected by the geomagnetic sensor during movement of the noise pattern acquisition device, store in a geomagnetic noise pattern storage unit a geomagnetic noise pattern which is a pattern representing a time-series change of the magnetic field strength detected by the geomagnetic sensor. This makes it possible to not only acquire a geomagnetic noise pattern but also detect a proper position with a simple structure and process at reduced cost.

An electromagnet comprises a pair of magnetic pole 1a and 1b, a return yoke 3, exciting coils 4 and 5, etc. In an interior portion of a magnetic pole, plural spacers 2a-2g are provided putting side by side in a horizontal direction. Each of the spaces 2a-2g is an air layer and a longitudinal cross-section is a substantially rectangular shape and the space has a lengthily extending slit shape in a vertical direction against a paper face in FIG. 1. The plural spaces are mainly arranged toward a right side from a beam orbit center O and an interval formed between adjacent spaces is narrower toward the right side. The electromagnet having a simple magnetic pole structure and a wide effective magnetic field area in a case where a maximum magnetic field strength is increased can be secured.

A magnetically enhanced convection heat sink comprises a heat sink member for dissipating heat from a heat source. A magnetic source creates a magnetic field concentrated at a first location, the intensity of the magnetic field decreasing from the first location to a second location. The heat sink member is positioned within the magnetic field and in a gas flow path between the first and second locations. Gas, having paramagnetic properties, entering the heat sink at the first location is heated by the heat sink member, and as the gas becomes warmer is displaced by cooler gas causing the warmer gas to move toward the second location as it is further heated by the heat sink.

In one illustrative embodiment, the present subject matter is directed to a device adapted to determine the position of a target magnet, wherein the device includes a pair of orthogonal magnetic field sensors laterally disposed along an axis that is substantially transverse to an axis defined by one that is nominally parallel to the direction of the target magnet. In another illustrative embodiment, the subject matter is adapted for use on an automated guided vehicle (AGV), whereby detection of the target magnet's location facilitates correction of the vehicle's heading and position while traversing an AGV system. The present subject matter is also directed to a method whereby the position of a target magnet may be determined by triangulation, utilizing trigonometric calculations based upon the strength and direction of the magnet field to determine the magnet's position relative to the magnetic field sensors.

An implantable medical device that includes a magnetic sensor circuit that senses the presence of an external magnetic field and provides a signal that is proportionate to the strength of the magnetic field. The implantable medical device uses the variable signal to determine whether a magnetic field is being applied that is selected to activate a preselected function. In one implementation, the preselected function is a power up sequence.

A new approach for locating an underground line described herein remains accurate in the face of bleedover by including both amplitude and phase from at least two magnetic field strength sensors in the measurement set. A numerical optimization step is introduced to deduce the positions and currents of each of several cables, of which one is the targeted cable and the others are termed bleedover cables. Furthermore, some embodiments of the method accounts for practical problems that exist in the field that relate to reliable estimation of cable positions, like the phase transfer function between transmitter and receiver, the estimation of confidence bounds for each estimate, and the rejection of false positive locates due to the presence of noise and interference.

A system for determining motion information including attitude and angular rate of a dynamic object. The system includes a magnetic-field sensing device to measure in the body coordinate frame of reference an intensity and / or direction of a magnetic field in three substantially orthogonal directions; an acceleration-sensing device adapted to measure total acceleration of the object in the body coordinate frame of reference; and a processor adapted to calculate attitude and angular rate by combining total acceleration measurement data and magnetic field measurement data with the kinematic model in a filter.

An implantable medical device includes a detector for detecting the presence of a magnetic field, where the presence of the magnetic field is detected in response to the strength of the magnetic field exceeding a first preselected magnetic field threshold. The device further includes a processor for adjusting a stimulation rate provided by the implantable medical device in response to determining that the strength of the detected magnetic field exceeds a second preselected magnetic field threshold. The second preselected magnetic field threshold is greater than the first preselected magnetic field threshold. In another embodiment, the implantable device includes a detector for detecting the presence of a high frequency (HF) radiation interference signal and a processor for adjusting a stimulation rate provided by the implantable medical device in response to determining that the strength of the detected HF radiation interference signal exceeds a preselected HF radiation threshold.

An integrated metal detector-portable medical device adapted to identify metals in a human body, where the metal detector is in connection with the portable medical device. The metal detector includes: at least one transmitting means adapted to generate a second magnetic field so as to induce a magnetic field generated by a metal; at least one sensor adapted to detect a magnetic field generated by the metals to be detected; and at least one signaling means adapted, upon detection of a magnetic field, to alert the identification of metals, if the intensity of a magnetic field is above a predetermined value.

A survey system is described for locating and classifying geophysical anomalies. It includes a moving platform equipped with a recording unit for recording the position of the platform. The system also comprises three first measuring units or sensors, adapted to record a varying electric field strength and a varying magnetic field strength at chosen intervals and thus positions, said first measuring units being adapted to measure said field strengths in three independent and mutually orthogonal directions at frequencies in a chosen range. The system includes a calculation unit for combining the measurements from each of said first sensors and calculating and recording as well as comparing the field strength vectors of the varying measured fields at each position, to find anomalies.

Embodiments in accordance with the present invention provide a perpendicular recording magnetic head whose dimensional dependency on the nonuniformity of magnetic field strength and distribution during manufacture is minimized, with narrowed tracks and without attenuation or erasure of adjacent track data while maintaining high magnetic field strength. According to one embodiment, a magnetic material (trailing / side shield) for creating a steep gradient of magnetic field strength is provided at a trailing side of a pole tip of a main magnetic pole piece and in a direction of the track width. The magnetic head is formed so that a gap (side gap length “gl”) between a side shield and a throat height portion of the pole tip progressively decreases with an increasing distance from an air-bearing surface, in a direction of an element height. That is, side gap length “gl” (2) at an element height position P2 is made smaller than side gap length “gl” (1) at an air-bearing surface position P1 so as to satisfy a relationship of gl(1)>gl(2).

The invention discloses a human body posture recognition method based on self-adaptive extension Kalman filtering, belonging to the field of body-area networks. The method comprises a model design step and a parameter design step. In the model design step, the angular speed and accelerated speed of the motion of a human body and the peripheral magnetic field intensity are collected by virtue of an inertial sensor through the characteristic that the motion angle of limbs of the human body can be reflected by a quaternion, and posture resolving is carried out based on a self-adaptive extension Kalman filtering method so as to obtain a posture quaternion. In the parameter design step, by utilizing a theoretical analysis and experiment method, a process noise covariance matrix is determined, and the value of a noise covariance matrix, a state initial value and an initial value of a state covariance matrix are measured, so that the continuous iteration of the self-adaptive extension Kalman filtering method can be realized, and the motion posture of the human body is continuously recognized in real time. The human body posture recognition method can be used as a human body posture recognition method in the fields of physical training, medical care, game design and the like.

The instant invention is directed toward a method and an apparatus for mapping the magnetic field strength or flux density of a magnetic source. The invention provides a robotically controlled sensor which is moved in a controlled manner throughout an area of flux density and the variations in the flux density are recorded. The position and recorded magnetic field strength at numerous points throughout the test area are recorded and the data is assembled into a graphical representation the end result of which is a multi-dimensional mapping of the magnetic field strength as a function of distance from the source. The testing method and apparatus provide a convenient methodology for accurately determining dosimetry and tissue penetration of therapeutic magnetic devices.

The invention discloses a method for separating iron, vanadium and titanium from schreyerite, which comprises the following steps: mixing schreyerite, sodium sulfate, a reducer and an adhesive, pressing into mineral coal pellets, drying the mineral coal pellets, filling into a rotary hearth furnace, and roasting at 1000-1300 DEG C for 20-60 minutes to obtain metalized pellets, wherein a neutral or micro-oxygenation atmosphere is in the rotary hearth furnace; crushing the metalized pellets, leaching at 70-90 DEG C while controlling the pH value at 3-5, and filtering the leach solution to obtain a vanadium solution; slurrying the leaching leftovers by ball milling while controlling the particle size at 0.045mm, and carrying out primary magnetic separation under the magnetic field intensity of 0.3-0.5T to obtain a nonmagnetic material which is a first titanium-rich material; carrying out secondary magnetic separation on the magnetic material under the magnetic field intensity of 0.02-0.04T to obtain a magnetic material which is a first iron-rich material; and slurrying the nonmagnetic material from the secondary magnetic separation by ball milling, and reseparating to obtain a second iron-rich material and a second titanium-rich material.

An electromagnet comprises a pair of magnetic pole 1a and 1b, a return yoke 3, exciting coils 4 and 5, etc. In an interior portion of a magnetic pole, plural spacers 2a-2g are provided putting side by side in a horizontal direction. Each of the spaces 2a-2g is an air layer and a longitudinal cross-section is a substantially rectangular shape and the space has a lengthily extending slit shape in a vertical direction against a paper face in FIG. 1. The plural spaces are mainly arranged toward a right side from a beam orbit center O and an interval formed between adjacent spaces is narrower toward the right side. The electromagnet having a simple magnetic pole structure and a wide effective magnetic field area in a case where a maximum magnetic field strength is increased can be secured.

A magnetic field sensing device for determining the strength of a magnetic field, includes four magnetic tunnel junction elements or element arrays (100) configured as a bridge (200). A current source is coupled to a current line (116) disposed near each of the four magnetic tunnel junction elements (100) for selectively supplying temporally spaced first and second currents. Sampling circuitry (412, 414) coupled to the current source samples the bridge output during the first and second currents and determines the value of the magnetic field from the difference of the first and second values. A method for sensing the magnetic field includes supplying a first current to the current line (116), supplying a second current the current line (116), sampling the value at the output for each of the first and second currents, determining the difference between the sampled values during each of the first and second currents, and determining a measured magnetic field based on the determined difference.

The invention concerns an arrangement for magnetic field measurement of a measurement object (in particular a gradient coil in a magnetic resonance apparatus) with a magnetic field sensor that is designed to measure a magnetic field of the measurement object and with a measurement mechanism on which the magnetic field sensor is arranged at a first position. The measurement object has detectable reference points that can be used for calibration of a spatial position of a position sensor. The calibrated position sensor is arranged at a second position of the measurement mechanism, such that, with the first position and the second position, a spatial position relative to the measurement object can be associated with each magnetic field strength that is measured by the magnetic field sensor.

The present invention relates to a magnetic sensor with a sensitivity measuring function and a method thereof. Magnetic sensitivity surfaces detect flux density, and a switching unit extracts magnetic field intensity information of each axis, and inputs it to a sensitivity calculating unit. The sensitivity calculating unit calculates the sensitivity from the magnetic field intensity information about the individual axes from the magnetic sensitivity surfaces. The sensitivity calculating unit includes an axial component analyzing unit for analyzing the flux density from the magnetic sensitivity surfaces into magnetic components of the individual axes; a sensitivity decision unit for deciding the sensitivity by comparing the individual axial components of the magnetic field intensity from the axial component analyzing unit with a reference value; and a sensitivity correction unit for carrying out sensitivity correction in accordance with the sensitivity information from the sensitivity decision unit.

The use of magnetic field sensing to perform sophisticated command control and data input into a portable device is disclosed. A magnetic field sensor is embedded or fixedly attached to a portable device to measure changes in the magnetic field strength and / or direction accompanying movement, motion or tilt of the device in one-, two- or three-dimensions when the portable device is used to air-write or make gestures.

Methods and apparatus for vertical chip-on-board sensor packages can comprise a vertical sensor circuit component comprising a first face, a second face, a bottom edge, a top edge, two side edges, input / output (I / O) pads and at least one sensitive direction wherein the I / O pads are arranged near the bottom edge. Such vertical die chip-on-board sensor packages can also comprise one or more horizontal sensor circuit components comprising a top face, a printed circuit board (PCB) mounting face, a vertical sensor circuit component interface edge, two or more other edges, and one or more sensitive directions wherein the vertical sensor circuit component interface edge supports the vertical sensor circuit component along the Z axis and conductively or non-conductively connects to the vertical sensor circuit component. The methods and apparatus provided include a multi-axis magnetometer for measuring the magnetic field intensity along three orthogonal axes comprising one or more magnetic field sensing circuit components mounted by their PCB mounting face to a PCB and a vertical magnetic sensor circuit component mounted to the PCB such that the vertical magnetic sensor circuit component is attached to and supported by the magnetic field sensing circuit component.

The position of a movable downhole component such as a sleeve in a choke valve is monitored and determined using an array of sensors, preferably Hall Effect sensors that measure the strength of a magnetic field from a magnet that travels with the sleeve. The sensors measure the field strength and output a voltage related to the strength of the field that is detected. A plurality of sensors, with readings, transmits signals to a microprocessor to compute the magnet position directly. The sensors are in the tool body and are not mechanically coupled to the sleeve. The longitudinal position of the sleeve is directly computed using less than all available sensors to facilitate the speed of transmission of data and computation of actual position using known mathematical techniques.

In an apparatus for controlling an unmanned autonomous operating vehicle having an electric motor supplied with power from a battery for operating lawn mower blades, and magnetic sensors for detecting intensity of a magnetic field of an area wire such that the vehicle is controlled to run about in an operating area defined by the area wire to mow lawn using the blades and to return to a charging device installed on the area wire so as to charge the battery, a distance from the area wire is detected based on the detected intensity of the magnetic field detected by the magnetic sensors, and a different one of returning trajectories defined along the area wire in advance with respect to distances from the area wire is selected, whenever the vehicle is to be returned.

The invention relates to a vehicle / vehicle flow detection method based on a three-axis magnetoresistive sensor, comprising the following steps: calibrating or calibrating the three-axis magnetoresistance sensor; obtaining the environmental magnetic field strength when there is no car, and obtaining the magnetic field strength when there is a car passing by; using Kaiser The FIR filter is designed to filter the measured magnetic field strength data to obtain the data sequence; the data sequence is binarized; whether there is a car is judged; when there is no car, interference is judged; when there is a car, interference is judged; the vehicle leaves the judgment; after the vehicle is judged The software forcibly resets the three-axis magnetoresistive sensor. It is characterized in that the method integrates the three-axis magnetic field information, which can fully reflect the disturbance information of the geomagnetic field when the vehicle passes by, the sensor can be placed arbitrarily, and the software reset method can effectively overcome the signal drift of the magnetic resistance sensor generated when the vehicle passes continuously Problems, through the judgment of vehicle entry, interference, and vehicle departure, it can ensure high detection accuracy and strong anti-interference ability. This method is easy to implement and is suitable for vehicle / traffic flow detection on traffic roads, bridges, squares, tunnels, etc. It can also be used in Vehicle detection in the parking lot for intelligent management.

A method and apparatus for Magnetic Resonance Imaging with specialized imaging coils possessing high Signal-to-Noise-Ratio (SNR). Imaging and / or Radio Frequency receiving coils include a ballistic electrical conductor such as carbon nanotubes, the ballistic electrical conductor having a resistance that does not increase significantly with length. Due to their enhanced SNR properties, system designs with smaller static magnetic field strength can be constructed for the same quality of imaging, leading to substantial reductions in system size and cost, as well as to enhanced imaging with existing MRI systems.

Apparatus and method for varying field strength in a magnetic resonance system while keeping a relatively uniform magnetic field distribution. In an embodiment, a two-pole, generally u-shaped magnet assembly generates a static and uniform magnetic field. The magnet assembly includes two facing magnet poles separated by an air gap. Holes may be formed with the magnet poles. The field control rods may be placed at a pre-determined distance into these holes and symmetrically or asymmetrically moved across each magnet poles in a controlled manner to change the magnetic field strength while keeping the uniform magnetic field distribution. Maximum magnetic field strength may occur when the rods are removed. Minimum magnetic field strength may occur when the rods are fully inserted.

A magnetic toner including at least: a binder resin; and a magnetic body, in which, when magnetization at a magnetic field strength of 397.9 kA / m and a coercive force of the magnetic toner are denoted by σs (Am2 / kg) and Hc (kA / m), respectively, a magnetic field strength at which the magnetic toner shows a magnetization value equal to 95% of σs is denoted by H95% (kA / m), and a number average particle size of the magnetic body is denoted by d (μm), H95%, Hc, and d satisfy the following expressions.151<H95%<200  (1)7.1<Hc<12  (2)40<Hc / d<150  (3)