146 results about "Low frequency magnetic field" patented technology

The invention relates to magnetic field shielding textile fabrics, a preparation method and application of the magnetic field shielding textile fabrics. The invention discloses the magnetic field shielding textile fabrics, which are formed by interlacing of permalloy wires and wearing yarns. The magnetic field shielding textile fabrics which are prepared by the permalloy wires can effectively attenuate a stationary magnetic field and a low-frequency magnetic field with DC - 300 Hz, are soft, can be cut, and can be applied to individual protection and magnetic field source shielding.

The invention provides a method and a device for preparing a nanoparticle reinforced aluminum base composite material, and relates to the technical field of particle reinforced aluminum base composite material preparation. The method and the device are characterized in that: a combination electromagnetic field is formed by a high frequency magnetic field and a low frequency magnetic field; and the combination electromagnetic field and an ultrasonic field are coupled and applied to a melt reaction synthetic process of an in-situ particle reinforced aluminum base composite material so as to synthesize the endogenous nanoparticle reinforced metal base composite material under the action of coupling the double-frequency combination electromagnetic field and the high-energy ultrasonic field. The method and the device overcome the defects that only the electromagnetic field or the ultrasonic field is applied, and the single electromagnetic field is coupled with the ultrasonic field; and under the action of coupling the combination electromagnetic field and the ultrasonic field, a reinforced phase is refined to nanoscale, the shape of the particles is rounded off, the bonding strength of the particles and a substrate is improved, particle dispersion is facilitated, and the comprehensive performance of the composite material is improved.

The invention provides an electromagnetic shielding room. The electromagnetic shielding room comprises a shielding shell, wherein a closed electrometric shielding space is defined inside the shielding shell, the wall surface of the shielding shell comprises a permalloy shielding interlayer, a supporting layer and an aluminum plate shielding interlayer from inside to outside, and the permalloy shielding interlayer and the aluminum plate shielding interlayer are fixed to the inner side and the outer side of the supporting layer respectively. The electromagnetic shielding room not only adopts permalloy to shield a low-frequency magnetic field, but also adopts aluminum plates to shield a high-frequency electromagnetic field, and therefore the high-frequency shielding effect is improved.

The invention relates to magnetic drive and in particular relates to a stainless steel magnetic field regulating device. The stainless steel magnetic field regulating device is composed of a magnetic field regulating iron block, a stainless steel substrate and a support frame. The magnetic field regulating iron block and the stainless steel substrate are compounded into an integrated structure, and due to the characteristics of the stainless steel, namely no magnetism, high mechanical strength, good heat resistance, small thermal expansion, good dimensional stability and long-term outdoor usability, and the excellent machinability and weldability of the stainless steel material, the defects of high polymer materials (nylon, epoxy resin and polyformaldehyde) used for common magnetic field regulating devices as substrates are overcome. Due to the corrosion resistance and the high temperature resistance of the stainless steel, the magnetic field regulating device becomes a novel insulating sleeve resistant to corrosion and high temperatures and having a magnetic field regulating function, and will play an important role under working conditions having requirements on high temperatures and corrosion prevention in the industries such as chemical engineering and ships. Besides, based on the magnetic shielding principle of a low-frequency magnetic field and the high mechanical strength of the stainless steel, a new magnetic field regulating device having an excellent magnetic field regulating effect also can be constructed.

A method and a device for continuous or semi-continuous casting of metal. A primary flow (P) of hot metallic melt supplied into a mold is acted upon by at least one static or periodically low-frequency magnetic field to brake and split the primary flow and form a controlled secondary flow pattern in the non-solidified parts of the cast strand. The magnetic flux density of the magnetic field is controlled based on casting conditions. The secondary flow (M, U, C1, C2, c3, c4, G1, G2, g3, g4, O1, O2, o3, o4) in the mold is monitored throughout the casting and upon detection of a change in the flow, information on the detected change monitored flow is fed into a control unit (44) where the change is evaluated and the magnetic flux density is regulated based on this evaluation to maintain or adjust the controlled secondary flow.

The invention provides a low-frequency communication system of a rotating electret mechanical antenna, belonging to the technical field of low-frequency communication. The system of the invention comprises a low-frequency magnetic field signal generating module and a magnetic induction signal receiving module. The low frequency magnetic field signal generation module comprises a motor and a charged electret in a mechanical antenna; the motor in the mechanical antenna is controlled to produce different rotational speed, electret is driven to rotate, magnetic field signals of different frequencies are produced. A desired communication signal is loaded onto the generated magnetic field signal, and the signal is transmitted to the receiving direction by a mechanical antenna. The magnetic induction signal receiving module receives the transmitted magnetic field signal through the magnetic field sensor, and demodulates and acquires the required communication signal. The invention utilizes the characteristics of ultra-low frequency and very-low frequency radio waves, adopts the method that a motor drives a charged electret to rotate, forms a low-frequency alternating magnetic field and transmits a magnetic field signal, can greatly reduce the antenna length and power consumption of a radio transmitter, and realizes stable low-frequency radio communication.

According to the invention the coupling unit comprises a ferromagnetic core (30) which encloses a conductor through which a low frequency current (1) is circulating in order to inject thereon a high frequency signal, is characterised in that current (1), circulating through the conductor or the magnetic field (3) produced in the coupling unit, is detected, and a compensating current is obtained based on the value obtained in the detection carried out, and the compensating current obtained in the coupling unit is injected through a low pass filter (9) to produce a magnetic field (4) equal and opposite to that produced by current (1) of the conductor in said coupling unit, and thereby avoiding the saturation of the magnetic care (30) without adding insertion loss. In general it is applied to communication systems which require the injection of a radiofrequency signal on a conductor, and in particular in systems which use the electricity grid as the transmission medium.

The invention relates to a method for carrying out information exchange by fully utilizing a near zone induction field of low-frequency electromagnetic wave in a non-stop car charging system. The system of the invention realizes that a car mounted mobile terminal 2 is arranged under a chassis of an automobile 1; a fixed terminal of a charging site is arranged above a carriageway surface 7; the mobile terminal and the fixed terminal mutually carry out the information transfer by the method of transmitting with a low-frequency magnetic field and receiving with inductance coupling in the near zone induction field of low-frequency electromagnetic wave; the fixed terminal 4 transmits the low-frequency magnetic field 3 by a transmitter coil 5 and the mobile terminal 2 receives the low-frequency magnetic field by a receiving coil 6; the transmission of the low-frequency magnetic field in the mobile terminal 2 and the receiving of the low-frequency magnetic field in the fixed terminal are completed respectively by inside corresponding inductance coils. The information exchange between the fixed terminal and the mobile terminal is carried out by a half duplex mechanism of the fixed terminal call and mobile terminal response. The design method provided by the invention achieves the purposes of high communication reliability, excellent information security and outstanding economical efficiency.

The invention provides a passive keyless entry and passive keyless start (PEPS) low-frequency calibration system and a PEPS low-frequency calibration method. The system comprises a three-dimensional position finder, a PEPS controller, a low-frequency signal generator, a controller local area network (CAN) communicator and an industrial personal computer. According to the embodiment of the invention, the CAN communicator is arranged to realize unified data interface communication between the three-dimensional position finder, the PEPS controller and the industrial personal computer, so that the synchronization performance of a PEPS low-frequency calibration work flow is ensured, and PEPS low-frequency calibration efficiency is improved; moreover, the industrial personal computer is used for regulating the driving current of low-frequency antennae, so that the power of low-frequency magnetic field signals generated by a plurality of low-frequency antennae is regulated; and the industrial personal computer is used for realizing the accurate conversion of a smart key between three-dimensional position finder coordinate system-based coordinates and vehicle body coordinate system-based coordinates, so that the positioning accuracy of the PEPS low-frequency calibration system is improved, and the accurate positioning of the smart key when the smart key is extremely close to a vehicle is realized.

The invention discloses a high Q-value resonance magnetic sensor employing frequency conversion output. The high Q-value resonance magnetic sensor includes a magnetic sensing unit, an oscillating circuit and a frequency detecting circuit. The magnetic sensing unit includes a magnetostriction unit and a high Q-value resonator integrated to the magnetostriction unit. The magnetostriction unit loads magnetostriction stress to the high Q-value resonator due to the effect of a magnetic field. The oscillating circuit excites the high Q-value resonator to oscillate and outputs electric signals carrying resonance frequency of the high Q-value resonator. The frequency detecting circuit detects the resonance frequency. The high Q-value resonance magnetic sensor provided by the invention can be used for high-flexibility detection of static, quasi-static and low frequency magnetic fields and is small in size and low in cost.

The invention discloses an electromagnetic shielding device for a signal line control circuit protector with a power surge protector. The electromagnetic shielding device is characterized in that an inner shielding body with 1-5 layers and an outer shielding body are of a closed edge-free box structure; a power surge protector (SPD) is arranged between the inner shielding body and the outer shielding body made of low-carbon steel plates with the manufacturing thickness of 10mm; by virtue of the signal line control circuit protector (SPD), current inducted by a high-intensity magnetic field is prevented from entering the shielding bodies along a power supply and signal cable; the power surge protector (SPD) connected with a grounding conductor of the shielding bodies is in grounding or equipotential connection, high current which is instantaneously inducted on the surface of the shielding bodies in the high-intensity magnetic field is discharged, a non-conductive and non-magnetic fixing framework is used for fixing the inner and outer shielding bodies, wire inlet and outlet holes are in a corresponding relationship and are not on the same line, and outward push-and-pull doors are arranged on the side surfaces of the shielding bodies. The electromagnetic shielding device is novel in design, ingenious in combination and easy to mount, and the shielding requirements on the high/low frequency magnetic field are met.

The invention discloses a methods for remote sensing on initial continuous current of artificially triggered lightning applying low-frequency magnetic field antenna. By applying the responsing frequecy characteristics of low-frequency magnetic field antenna outside the effective detected frequency band, adopt numerical integration method to process mathematically the waveform of magnetic field obtained near channel of artificially triggered lightning, which can effectively remove the influence of noise signal in measuring process and obtain the characteristic discharging process in experiment of artificially trigered lightning, namely the high time solution waveform of initial continuous current. The manufacturing and erection of low-frequency magnetic field antenna is relatively easy and with low cost, whose parameters such as gain can be adjusted based on different experimental requirements, with strong practibility; besides, the result of artificially triggered lightning of inversion demonstrates high signal-to-noise ratio, which means during the experiment, the sensor doesn't need to be deployed on current path, and under situations when no lightning current such as natural lightning can be directly measured, this inversion method can help obtain the time-varying waveform in process of continuous discharging.

The invention belongs to the technical field of a low-frequency magnetic field radiation system in an electromagnetic biological effect research, and in particular relates to a method for providing a stable and uniform magnetic field environment to a power frequency low-intensity magnetic field biological effect experiment. The method at least comprises the following steps of: installing a magnetic field radiation system on a cell incubator, and arranging a Helmholtz coil in the magnetic field radiation system inside the cell incubator; arranging a radiation carrying support in the center shaft of the Helmholtz coil; and inputting a stable power frequency sine wave signal into the Helmholtz coil, so that a stable and uniform magnetic field is generated inside the Helmholtz coil; and placing a separation on the radiation carrying support after the magnetic field radiation system is preheated for a certain period to perform a biological effect experiment. The method provided by the invention has the advantages that operation is convenient, temperature and humidity are controllable, running can be carried out for a long term, magnetic field is stable and uniform and uniform area is large, and the intensity of the magnetic field can be checked and calculated in real time by virtue of an ampere meter, so that the requirement for the separate magnetic field biological effect can be completely fulfilled.

The invention provides a resonance type magnetic sensor sensitive unit and a digital frequency output magnetic sensor. The magnetic sensor sensitive unit includes a high-Q value resonator, and magnetostrictive units disposed at the upper side and lower side of the high-Q value resonator respectively; the magnetostrictive units generate magnetostrictive stress under the action of magnetic fields and load the stress onto the high-Q value resonator; insulating spacers are disposed between the high-Q value resonator and the magnetostrictive units; and the stress generated by the magnetostrictive units is loaded to the high-Q value resonator through the transmission of the insulating spacers. The magnetic sensor sensitive unit of the invention can be used for high-sensitivity detection of static, quasi-static and low-frequency magnetic fields, and is small in size and low in cost.

The invention relates to a detection device and a detection method thereof, in particular to a DC and low frequency magnetic field signal detection device and a detection method thereof. The DC and low frequency magnetic field signal detection device is characterized by comprising a probe device (30) and a detection module (31) connected with the probe device (30). Thus, the invention has the following advantages that the design is reasonable, the structure is simple, noise is lower, the practicability is complete, the output zero of the entire test device can not be changed along with temperature variation so that test errors are greatly reduced, and the output signal of the entire device can not produce nonlinearity.

The present invention provides methods for the fabrication CNT dispersions using polysaccharides, especially hemicelluloses, and most advantageously xylan.

The present invention also provides methods to isolate, and purify hemicelluloses from plant materials.

The present invention provides methods and compositions for the coating of solid surfaces using CNT dispersions.

One currently preferred method coating of a surface is electrospraying the CNT dispersion.

The present invention provides electrically conducting materials that can replace conducting plastics, graphite, and even some metals as electrical conductors.

In one embodiment the present materials can be used as stealth coatings.

In another embodiment the present materials can provide shield against high frequency electromagnetic radiation, while being permeable to low frequency magnetic field.

In one specific application the dispersion fabricated from double walled carbon nanotubes (DWNTs), and xylan can be used to fabricate transparent electrically conducting films.

In one embodiment of the present invention the surface films will be cross-linked, and these films can be used in multiple applications including supercapacitors.

Disclosed are: a mobile device, in particular a mobile Passive Keyless Entry, PKE, key device, and an associated method for providing 3D field values of a magnetic field H; an evaluation device for use in a PKE system having a Mobile device and an associated method for determining the direction of a magnetic field vector H=(x, y, z), which is present locally at a position of a 3D antenna of the mobile device; and a PKE system having a PKE base structure, to which preferably the mobile device is associated and which has at least a first base structure antenna, which is operable to emit the, particularly low frequency, magnetic field, the mobile PKE device and the evaluation unit. The mobile device and the associated method are characterized by providing, in addition to providing a first, second and third value v_x, v_x, and v_x indicative of the local X-component x, Y-component y, and Z-component x of the magnetic field vector H, a sum value v_S indicative of the sum |S|=|x+y+z| of the local X-, Y-, and Z-components of the magnetic field vector H. The evaluation device and the associated method are characterized by providing the vector V yielded as a vector, which has the direction of the magnetic field vector H, and may be capable to discriminate, if a one-dimensional Relay Station Attack has occurred or if a regular wireless connection has been established between the PKE base structure and the associated mobile device.

The invention relates to the laser welding field, in particular to a laser welding method and device additionally adopting variable-frequency magnetic fields. Excitation coils with different coil numbers are adopted to excite the variable-frequency magnetic fields with different intensities and different frequencies, the magnetic field radiation areas of welded pieces are made to be sequentially in the to-be-welded state, the molten state and the to-be-post-processed state according to the processing time sequence. Additionally arranged magnetic field devices which can excite different frequencies and different intensities and move along with a laser head are adopted to conduct pre-welding, during-welding and post-welding treatment on different areas with magnetic fields of different intensities and frequencies, the to-be-welded pieces are preheated under the action of the heating effect of the magnetic fields, so that the pool depth is lowered; during laser welding, the method of additionally exerting a high-frequency magnetic field is adopted in a weld pool area, and the weld pool area is stirred; and when laser welding is completed, post-welding heat treatment is conducted on the welded area with a low-frequency magnetic field. By the adoption of the laser welding method and device additionally adopting the variable-frequency magnetic fields, the temperature gradient of theweld pool can be effectively reduced, the temperature of the weld pool is evenly distributed, air pores and other defects are reduced, and the welding quality is improved.

The invention discloses a wireless charging receiving end, a wireless charging transmitting end, a wireless charging system, a wireless charging control method and an electric vehicle, whichrelate tothe technical field of wireless charging. A low-frequency magnetic field receiving coil of the receiving end converts a low-frequency magnetic field into an induction signal; when each low-frequency magnetic field transmitting coil stops working, the receiving end controller allocates a signal characteristic different from the signal characteristic of the current induction signal to each low-frequency magnetic field transmitting coil, and sends the corresponding relationship between each low-frequency magnetic field transmitting coil and the allocated signal characteristic to the wireless charging transmitting end; and the controlleris also used for determining the relative positions of the power transmitting coil and the power receiving coil by utilizing the induction signals with the distributed signal characteristics when the low-frequency magnetic field transmitting coil works. And the transmitting end controller controls the inverter circuit according to the corresponding relationso as to enable each low-frequency magnetic field transmitting coil to work. Mutual interference between low-frequency magnetic field signals of adjacent parking spaces can be avoided by utilizing the receiving end and the transmitting end.

The invention discloses a voice coil motor powered by electromagnetic induction, which comprises a moving coil, a low-frequency magnetic circuit component and a high-frequency induction power supply component. The high-frequency induction power supply component comprises a high-frequency magnetic core and a high-frequency power supply coil. The moving coil is coupled to the high-frequency power supply coil through the high-frequency magnetic core, and is used for generating an induction current in the moving coil. The low-frequency magnetic circuit component is used for providing a low-frequency magnetic field, and includes a permanent magnet and a magnetizer with a groove. The permanent magnet is attached to one side of the inner wall of the groove. An air gap is formed between the permanent magnet and the other side of the inner wall of the groove. The moving coil moves in the air gap. The flying wire of the mover coil of the voice coil motor is removed, the problem that the flying wire structure of the traditional moving coil is easy to break is solved, the reliability of the voice coil motor is improved, and the service life of the voice coil motor in the occasion of frequent reciprocating motion is greatly increased. Meanwhile, the reciprocating frequency of the voice coil motor with stroke above millimeter level is also improved.

A low-frequency magnetic field energy collector using a piezoelectric combined pitchfork comprises the piezoelectric combined pitchfork, permanent magnets and a base (7), the piezoelectric combined pitchfork is composed of a first rectangular elastic metal fork arm (3), a first piezoelectric plate (5), a second rectangular elastic metal fork arm (4) and a second piezoelectric plate (6); the first piezoelectric plate is fixed to a transition end of the first rectangular elastic metal fork arm; the second piezoelectric plate is fixed to a transition end of the second rectangular elastic metal fork arm; the permanent magnets are symmetrically pasted to free ends of the two fork arms by gluing, the first permanent magnet (1) is mounted at an end of the first rectangular elastic metal fork arm (3), and the second permanent magnet (2) is mounted at an end of the second rectangular elastic metal fork arm (4); it is ensured that severe coupling is generated between the two fork arms to acquire maximum mechanical vibration. The piezoelectric combined fork is used as an energy collection and conversion unit, and it is possible to efficiently acquire weak low-frequency magnetic field energy.

The present invention provides an electromagnetic metamaterial that can be used in the fields of radio energy transmission systems and electromagnetic protection, has a magnetic permeability near zero, and has the ability to absorb low-frequency magnetic fields and to be transparent to high-frequency electromagnetic waves. At least one of the upper and lower surfaces of the base material is provided with a fractal structure layer, and the fractal structure layer includes an annular metal wire and a fractal structure metal wire arranged on the surface of the base material; the fractal structure The metal wire is located inside the ring-shaped metal wire and surrounded by the ring-shaped metal wire; the present invention can realize electromagnetic radiation absorption of low-frequency magnetic fields and various harmonics in application, and can reduce its impact on surrounding equipment or The hazards of personnel, and at the same time have the characteristics of high-frequency transparent two-way electromagnetic materials, so that the electromagnetic metamaterials of the present invention can be used in the fields of radio energy transmission systems and electromagnetic protection.

A biological sample detector based on the nonlinear magnetization characteristic of magnetic beads. The detector comprises two Helmholtz coils (1, 2) and a magnetic induction coil array (3). The axes of the two Helmholtz coils (1, 2) intersect vertically, and a combined magnetic field is produced through the interaction of the two Helmholtz coils (1, 2), and acts on the magnetic beads to generate a nonlinear magnetization signal. One of the two Helmholtz coils generates a low frequency magnetic field, and the other one of the Helmholtz coils generates a high frequency magnetic field. The magnetic induction coil array (3) is used to detect the nonlinear magnetization signal. The magnetic induction coil array (3) is wrapped around a sample tube array (4) with the inside provided with magnetic bead-biological sample molecules-probe molecule products, and is placed in an internal space formed by the Helmholtz coils (1, 2). The magnetic induction coil array (3) is composed of a plurality of solenoid coils, and the axes of the plurality of the solenoid coils parallel to each other. The axial direction of the magnetic induction coil array (3) is perpendicular to a plane formed by the axes of the two Helmholtz coils (1, 2).

The invention relates to a low-frequency magnetic field generator used for cell experiment research. Its basic components include: a magnetic field generator part, a coil part and a patch clamp recording part. The magnetic field generator part mainly includes: MCU, human-computer interaction module, Signal generation module, power amplification module, power supply module, human-computer interaction module to realize the input and display of user commands, MCU as the core to realize the generation of signals and the control of various parameters, etc., the coil is fixed on the patch clamp microscope through a movable plastic arm On the mirror arm, the user selects the waveform, intensity and duty cycle of the signal through the human-computer interaction part, and the single-chip microcomputer controls the signal generation part to output the corresponding signal according to the selected parameters, and then sends it to the power amplifier circuit to output a large current to drive the diaphragm The coil on the clamp generates the magnetic field expected by the user, stimulates and records the electrophysiological properties of the cells through the patch clamp electrodes.