34 results about "Magnetostatics" patented technology

Current-perpendicular-to-the-plane (CPP), current-in-to-the-plane (CIP), and tunnel valve type sensors are provided having an antiparallel (AP) coupled free layer structure, an in-stack biasing structure which stabilizes the AP coupled free layer structure and a nonmagnetic spacer layer formed between the in-stack biasing layer and the AP coupled free layer structure. The AP coupled free layer structure has a first AP coupled free layer adjacent to the nonmagnetic spacer layer, a second AP coupled free layer, and an antiparallel coupling (APC) layer formed between the first and the second AP coupled free layers. The net moment of the AP coupled free layer structure has an antiparallel edge magnetostatic coupling with the in-stack biasing structure. At the same time, the first AP coupled free layer has an antiparallel exchange coupling with the second AP coupled free layer. By forming the second AP coupled free layer with a thickness greater than a thickness of the first AP coupled free layer, the AP coupled free layer structure has a net magnetic moment in the direction of the second AP coupled free layer moment. The non-magnetic spacer layer is chosen so that first AP coupled free layer has a parallel interlayer (Neel or Orange-peel or positive exchange) coupling with the in-stack biasing structure, so that the interlayer coupling adds to the edge magnetostatic coupling to increase a stability of the AP coupled free layer structure.

The invention belongs to the technical field of magnetizing, and aims to provide a magnetostatic field magnetizing device and method at a normal temperature. The device is compact in structure, stable in performance, safe and reliable, capable of saving energy and high in magnetizing efficiency. The device comprises an upper magnetizing source device and a lower magnetizing source device. The upper magnetizing source device comprises an upper supporting plate, yoke iron bodies and magnetizing magnetic steel bodies. Each yoke iron body is in the shape of a cuboid, and the four side faces of each yoke iron body are each provided with one magnetizing magnetic steel body in a pasting mode. The lower ends of the yoke iron bodies protrude out of the magnetizing magnetic steel bodies, and magnetizing heads are pasted in the central positions of the yoke iron bodies. The bottoms of the magnetizing magnetic steel bodies are fixedly attached to the upper supporting plate. A through groove is formed in the central position of the upper supporting plate, and the magnetizing heads of the yoke iron bodies are located in the through groove of the upper supporting plate. The structure of the lower magnetizing source device is the same as the structure of the upper magnetizing source device, and the lower magnetizing source device and the upper magnetizing source device are symmetrically arranged. A material guide plate is arranged between a lower supporting plate of the lower magnetizing source device and the upper supporting plate of the upper magnetizing source device, material guide through grooves are formed in the material guide plate, and the positions of the material guide through grooves correspond to those of the magnetizing heads. The lower supporting plate is fixedly connected with the upper supporting plate.

A system and method for monitoring a subject are presented. The system includes a sensing device including at least one magnetic source to generate a magnetic field and an array of magnetic sensors disposed within the magnetic field. The sensor array obtains a plurality of magnetic field measurements at a plurality of locations along a vessel carrying a fluid including one or more magnetic particles. Further, the system includes a processing subsystem communicatively coupled to the sensing device, where the processing subsystem determines variations in the measurements caused by magnetization-relaxation of the magnetic particles based on a coupled model that defines behavior of the fluid in the varying magnetic field based on principles of magnetization-relaxation, bulk motion of the magnetic particles towards a determined gradient of the magnetic field, magnetostatics, and conservation of momentum. The processing subsystem estimates values of one or more desired parameters based on the determined variations.

One kind used for then the hold type nuclear magnetic resonance instrument quiet the magnetic field take place equip of always body, from a hollow cylinder form always body and a hollow hemisphere form always body constitute, hemisphere form the stalk of body always cuts one that the noodles folds to impose a cylinder form always a body to carry noodles up. Hollow cylinder form always body from shape homology, the magnetic field strength is equal, magnetizing a direction to revolve a direction for the body double and fan-shaped the body always constitutes. Hemisphere form always body is with the outside path be equal to a cylinder form a body always of outside path, inside path small in cylinder form always body of inside path, the stalk runs parallel with the semicircle wreath of magnetic field direction, the stalk which rounds to run parallel with a magnetic field direction revolves to get of, the hemisphere's form the body always closes the cylinder form body to carry a department at hollow type cylinder form the outside side of the body at the right moment. Hemisphere form always body and cylinder form the body always compensates a cylinder form consistently and in order to a body to always carry the horizontal magnetic field of department in the on-line magnetic field direction of the cylinder stalk inside the chamber.

The invention relates to a closed-loop control system for a nuclear magnetic resonance gyroscope of three working media, wherein a gas chamber filled with an alkali metal gas and three working media is arranged in a nuclear magnetic resonance gyroscope device; the three working media make Larmor procession; Larmor procession frequency values omegaa1, omegaa2 and omegaa3 of the three working media are acquired through a signal separator and a frequency comparator; an arithmetic device is used for calculating the temperature T, the magnetostatic field magnitude B0 and the system angular velocity omegaR in the device; a temperature controller is used for controlling a heating chip to keep the temperature T of the nuclear magnetic resonance gyroscope device according to a feedback signal of temperature T; a magnetic field controller is used for controlling the magnetostatic field magnitude B0 in a magnetostatic field coil nuclear magnetic resonance gyroscope device according to the feedback signal of magnetostatic field magnitude B0; a signal generator and a summator are used for controlling the magnitude of the driving magnetic field coil current according to the Larmor procession frequency values omegaa1, omegaa2 and omegaa3 of the three working media and causing the three working media to keep the resonance frequency spot. The closed-loop control system provided by the invention is used for performing closed-loop control on the magnetostatic field and the temperature at the same time, so that higher precision of the system angular velocity can be achieved.

The invention relates to the technical field of static characteristic optimization, and discloses a method for optimizing a reluctance static characteristic based on sensing direction. The method comprises the following steps: 1, setting an easy-axis bias field and a hard-axis bias field as constant values, and setting the value of the sensing direction to obtain a sensing curve; 2, selecting the maximum value hFM of a specific magnetic field measurement range, subjecting the sensing curve to optimization of an objective function, which is described in the specification, to obtain a sensitivity k, a bias b and an absolute error Err; 3, selecting the maximum values hFM of different magnetic field measurement ranges and repeating the step 2; 4, selecting the values of different sensing directions, repeating steps 1 to 3, and obtaining N relation curves between the absolute error Err and the magnetic field measurement ranges in the same two-dimensional coordinates; 5, obtaining a corresponding value of the sensing direction that makes a minimum absolute value under the specific magnetic field measurement range, the specific easy-axis bias field and the hard-axis bias field according to the two-dimensional coordinates. By adjusting the sensing direction, a larger linear area can be obtained.

The invention discloses a high-precision static magnetic suspension accelerometer, and the accelerometer is used for measuring the linear accelerometer of an aircraft. The accelerometer comprises a vacuum magnetic shielding chamber system, a magnetic field displacement sensing system, a static magnetic suspension control system, and an examination magnet. The accelerometer employs the technology of magnetic field displacement sensing to achieve the real-time precise measurement of the position and posture of the examination magnet, and employs the technology of static magnetic suspension control to achieve the precise regression control of the position and posture of the examination magnet, thereby enabling the examination magnet to be continuously controlled at the center of a chamber, i.e., the center of mass of a space aircraft. When an external nonconservative force acts on the space aircraft, the size and direction of the acceleration can be precisely measured finally through the measurement of the current of a position control coil because the acceleration of the aircraft will be in direct proportion to the amplitude of the current of the position control coil. The accelerometer can avoid a technical bottleneck of high-precision machining, is simple in manufacturing technology, and can achieve higher-precision acceleration vector measurement.

The invention relates to a magnetostatic method for online monitoring vibration marks of a magneto-conductive continuous casting billet. The magnetostatic method comprises the following steps that a permanent magnet is arranged on the surface of a continuous casting billet in the continuous pulling down process, wherein the magnetization direction of the permanent magnet is perpendicular to the billet surface, to be detected, of the continuous casting billet to be detected; by utilizing calibration of a vibration mark-free continuous casting billet with the same material as the continuous casting billet to be detected, a force sensor is used to determine the counter-force F0' applied to the magnetostatic force F0 on a magnet; and the continuous casting billet, to be detected, with the vibration marks is determined and passes through the lower side of the permanent magnet, a bulge or a depression formed in the surface of the continuous casting billet to be detected can make the permanent magnet vary by subjecting to the counter-force F0' of the magnetostatic force, the force sensor which is connected with the end part of the permanent magnet is used to measure the counter-force F0' applied to the permanent magnet, and thus information of the vibration marks of the surface of the continuous casting billet to be detected is obtained. The magnetostatic method for online monitoring the vibration marks of the magneto-conductive continuous casting billet is simple and convenient, is accurate in result and can monitor variations of the vibration marks according to signal analysis on defects.

The general field of the invention is that of matter-wave gravimeters. The gravimeter according to the invention comprises at least:means for generating, for capturing and for cooling a cloud of ultra-cold atoms;means of transferring the atoms into a superposition, with equal weights, of a first internal electronic state called state |1>) and of a second internal electronic state called state |2> comprising the application of at least a first microwave field and of a radiofrequency field;means for separating the atoms into two wave packets for a given period of time under the effect of at least a second microwave field, the said separation leading to a phase-shift associated with the local gravitational field;calibration means allowing a “magic” magnetostatic field to be determined for which the difference in energy between the first internal electronic state and the second internal electronic state is independent, to a first order, of the fluctuations of the magnetostatic field.

The invention relates to a method for nondestructively testing micro-defects in sheet ferromagnetic materials based on measurement of magnetostatic force and belongs to the technical field of nondestructive testing. The method comprises the following steps: arranging a permanent magnet on the surface of a calibration sheet, and measuring reacting force of magnetostatic force which acts on the permanent magnet by using a force sensor; arranging the permanent magnet on the surface of a sheet to be measured, and measuring reacting force stressed by the permanent magnet by using the force sensor; and comparing the two reacting forces, if the same, determining that a surface defect or an internal defect does not exist on the sheet to be measured, and if different, determining that a surface defect or an internal defect exists on the sheet to be measured. The method is simple in measurement process, relatively low in detection cost and reliable in detection result; the measurement accuracy is high, and micron order micro-defects in the magnetic sheets can be detected; the detection speed is high, and sheet materials can be rapidly detected on line in real time.

The invention relates to an oscillation welding method under the action of a magnetic lens and a magnetic lens device. The method controls welding arc by an additional magnetic field and exerts an alternating magnetic field in the direct current welding process and a direct current (DC) magnetostatic field in the alternate current (AC) process so as to produce electromagnetic oscillation; meanwhile, the welding arc is effectively controlled by the magnetic lens device. The magnetic lens device has a double pole-shoe magnetic lens device arranged above a welding seam and a single pole-shoe magnetic lens device arranged under the welding seam. The magnetic lens device exerts the electromagnetic oscillation and the grain structure of the welding seam is converted from the original bulky columnar crystal to the fine equiaxial crystal, the magnetic field strength around the pole shoe of the magnetic lens device can be doubled when the magnetic lens device is used, which can control the electric arc more effectively. The magnetic lens device provided by the invention has the advantages of reasonable design, simple and compact structure, easy realization and convenient operation.