33results about How to "Suppression of eddy current loss" patented technology

The invention relates to an iron-carbon nano composite electromagnetic wave absorption material and a preparation method thereof. Carbonyl iron, methane and acetylene serving as main raw materials are directly synthesized into the iron-carbon nano composite material in a gas-phase reaction device at the temperature of between 300 and 1,000 DEG C. The nano composite material has good stability and uniformity. The iron-carbon nano composite material is wrapped outside iron nano granules by nano-scale C to form a C film; and the iron-carbon nano composite material has the characteristics of good electromagnetic wave absorption performance, wide absorption coverage frequency range, strong corrosion and oxidation resistance and low cost, and is applicable to electromagnetic shielding in a radio communication system, electromagnetic radiation and leakage of equipment of high frequency prevention, microwave heating and the like, construction of microwave darkrooms and hiding technology.

The invention relates to a three-dimensional porous sheet ferroferric oxide/carbon nanometer electromagnetic wave absorption material and a preparing method thereof. Carbon in the electromagnetic waveabsorption material forms a three-dimensional framework of a flower-shaped structure, and ferroferric oxide particles wrapped by carbon are evenly distributed on a carbon base body. The preparing method includes the steps of firstly, making trivalent inorganic ferrite and urea as precursors for synthesizing ferroferric oxide dissolved together with a surface active agent in a solvent according toa certain mass ratio to have a reaction under closed conditions, washing and drying a product after the reaction is completed to prepare hydroxyl ferric oxide, and calcinating the prepared hydroxyl ferric oxide to obtain ferric oxide powder; secondly, mixing the ferric oxide powder in the first step with a carbon source to have a reaction under closed conditions to obtain the three-dimensional porous sheet ferroferric oxide/carbon nanometer electromagnetic wave absorption material. The electromagnetic wave absorption material is high in saturated magnetic susceptibility, large in coercivity,light in weight, strong in oxidization resistance and excellent in electromagnetic wave absorption performance.

The invention belongs to the field of material preparation, in particular to a method for preparing high-silicon steel from low-silicon steel. The method comprises the following steps: a, using a low-silicon steel hot-rolled plate with a smooth surface as a base material, and carrying out cold rolling so as to obtain a thin plate; b, carrying out acid pickling on the thin plate so as to remove oil stains and an oxide film on the surface; c, in a temperature range of 450-550DEG C, carrying out thermal insulation on the cold-rolled thin plate in a solid siliconizing agent for 20-30 minutes; d, in a temperature range of 750-820DEG C, carrying out solid siliconizing on the thermally insulated thin plate for 10-30 minutes in the solid siliconizing agent; e, rolling the thin plate at a temperature of 350-450DEG C; f, at a non-oxidization atmosphere, carrying out diffusion annealing on the siliconized thin plate at a temperature of 850-1100 DEG C for 30-480 minutes; and g, under nitrogen protection, rapidly cooling the thin plate subjected to diffusion annealing to a room temperature and coating a MgO coating. The method is characterized by low raw materials and simple processing and treating. The problems of steel band surface serious corrosion and Fe losses, caused by high Cl-ion concentration in the process of preparing the high-silicon steel by a vapor deposition process are solved.

The invention relates to a magnetic porous cobalt hollow ball electromagnetic wave absorption material, a preparation method and application of the material. The magnetic porous cobalt hollow ball electromagnetic wave absorption material is composed of monodispersed porous hollow balls, wherein the external diameter of each porous hollow ball is 2-6 microns, and the thickness of each ball shell is 100-200nm. The hollow balls are formed by cobalt particles, wherein the diameter of each cobalt particle is 60-200nm, and 10-100nm air voids exist among the cobalt particles. The preparation method includes the steps of using precursors like cobaltous acetate and precipitants like urea, and polyving akohol or polymethyl methacrylate or polyvinylpyrrolidone as surfactants, enabling the surfactants to be dissolved in ethyl alcohol solvents or methanol solvents to obtain cobaltous hydroxides through reaction, and enabling the cobaltous hydroxides and potassium borohydride to be reacted in water or ethanol solutions to obtain the monodispersed porous cobalt hollow balls. The prepared porous cobalt hollow ball material is good in evenness and dispersity, small in density, strong in magnetism and good in electromagnetic wave absorption performance and can be used as the electromagnetic wave absorption material.

The invention discloses a non-contact electric energy transmission system for a vertical drilling system. The non-contact electric energy transmission system comprises a transformer, a series resonant inverter circuit, a rectification output circuit and an inverter control circuit, wherein the transformer is a separate transformer which comprises primary magnetic cores and secondary magnetic cores which are separated from one another; a plurality of grooves which are formed along the axis are formed in the outer circular surface of a power main shaft of the drilling system and in the inner circular surface of a hole straightening loop respectively; the primary magnetic cores are arranged in the grooves of the power main shaft; the secondary magnetic cores are arranged in the grooves of the hole straightening loop; the central angle theta formed by the circular arcs on the surfaces of the secondary magnetic cores opposite to the axis of the power main shaft meets a certain relationship, so that the magnetic resistance between the primary magnetic cores and the secondary magnetic cores is constant and is not affected by rotary motion; the phase difference between the voltage and the current is calculated by detecting an output voltage signal and an output current signal of the inverter circuit; the system is kept to work in a resonant state by adjusting the switching frequency, so that the hardware circuit is simplified and the flexibility for phase detection is improved.

The invention discloses design of a special superconductor low-temperature cooling structure applied to a superconductive magnetic suspension micro thrust measurement system. The superconductor low-temperature cooling structure comprises a refrigerator, a cooling base, a cooling copper column, a cooling copper ring, a superconductive stator array, an Al<2>O<3> ceramic cover plate, an indium sheet, graphite gaskets, an anti-radiation screen and the like. Specific to the requirements of high cooling efficiency and low eddy current loss of the cooling structure of the measurement system, a dual-path conduction cooling structure with low eddy current effect is designed; according to the cooling structure, the heat conduction gaskets capable of lowering contact heat resistance are arranged on the respective contact surfaces of corresponding parts, and by virtue of setting of the anti-radiation screen, radiation heat flow from the exterior can be isolated; and when the measurement system is in use, the Al<2>O<3> ceramic cover plate and the graphite gaskets with a weak eddy current effect are positioned in a region with severe magnetic field changes, while the cooling base, the cooling copper ring and the cooling copper column with an obvious eddy current effect are isolated from the region, so that the eddy current loss of the conduction cooling structure is suppressed by virtue of the conduction cooling structure layout.

The present invention provides: (1) a magnetic coil in which magnetic particles 14 form an aggregate and the aggregate of the magnetic particles is disposed in a vessel 12 while the magnetic particles are keeping a particle state, (2) a magnetic field shield member for shielding magnetic field generated from a magnetic field generation member, the magnetic field shield member in which magnetic particles form an aggregate and the aggregate of the magnetic particles is disposed in a vessel 12 while the magnetic particles are keeping a particle state, and an electrophotographic apparatus using them.

Disclosed is a dynamo electric machine wherein at least one coil end in the axial direction of a stator is bent toward the radial inside of the stator core and formed as a bent coil end, and eddy current loss caused by a magnetic field generated from the bent coil end is minimized. Torque of the rotor in the rotational direction is enhanced in such a dynamo electric machine by efficiently utilizing the magnetic field generated from the bent coil end. The rotor (2) includes a substantially cylindrical rotor core (3), and a counter end plate (4) which is fixed to the axial end face (31) of the rotor core (3) concentrically with the rotor core (3) while facing the bent coil end (81), wherein the counter end plate (4) principally comprises powder material produced by pressure molding the magnetic powder, i.e. the powder of a magnetic material, and a nonconductive state where an induction current produced by the magnetic field generated from the bent coil end (81) is regulated is brought about between the magnetic powders composing the powder material.

The invention discloses an orthogonally magnetized controllable resistor based on direct current memory flux magnetism helping and adjusting. The resistor comprises an alternating current working winding, an alternating current working iron core and a direct current memory flux orthogonal magnetism helping and adjusting device. The direct current memory flux orthogonal magnetism helping and adjusting device is composed of an orthogonal direct current working iron core, a direct current exciting winding, and an aluminum-nickel-cobalt permanent magnet with a direct current magnetic field memory function. Openings are formed in the two sides of the orthogonal direct current working iron core, a core column of the alternating current working iron core penetrates from the opening in one side of the orthogonal direct current working iron core, the aluminum-nickel-cobalt permanent magnet is embedded into the opening in the other side of the orthogonal direct current working iron core, the direct current exciting winding is wound around the aluminum-nickel-cobalt permanent magnet, and the alternating current working winding is wound around the alternating current working iron core. The resistor is simple in structure, the reactance is linear, and can be smoothly adjusted within a wide range, electromagnetic loading of the direct current exciting winding is greatly relieved through aluminum-nickel-cobalt magnetism helping and adjusting, and the running efficiency of a system is improved.

The invention discloses a magnetoelectric coupling-based bulk acoustic wave magnetic field sensor and an optimization method thereof. The magnetoelectric coupling-based bulk acoustic wave magnetic field sensor structurally comprises a magnetic composite film and a bulk acoustic wave resonator, the magnetic composite thin film comprises a FeGaB magnetostrictive thin film and an Al2O3 thin film inserted into the FeGaB magnetostrictive thin film; the bulk acoustic wave resonator comprises a Mo electrode film, an AIN piezoelectric film and a silicon substrate which are arranged in sequence. According to the bulk acoustic wave magnetic field sensor, the composite magnetic film is adopted, eddy current loss is restrained, and the soft magnetic characteristic is enhanced; meanwhile, a piezomagnetic phase/piezoelectric phase double-layer structure design is adopted, so that the magnetoelectric (ME) coupling efficiency is improved; the resonance is utilized to enhance the ME coupling effect, and the thickness of the piezoelectric phase/piezomagnetic phase and the electrode layer is designed, so that the sensor works at the ferromagnetic resonance frequency of the composite film, and the energy conversion efficiency is further improved. Therefore, the performance optimization method of the bulk acoustic wave magnetoelectric coupling magnetic field sensor is obtained.

The invention relates to an inverter, an inverter control method and a motor system. The inverter comprises a control device and a single-phase control circuit, the single-phase control circuit comprises more than two bridge arm circuits, and each bridge arm circuit comprises an upper bridge arm control switch and a lower bridge arm control switch. One single-phase control circuit in the inverter comprises more than two bridge arm circuits which are connected in parallel, the plurality of bridge arm circuits can be conducted in a staggered manner, the switching times of each control switch in each bridge arm circuit are shared, the equivalent switching frequency of the inverter is improved, the upper limit of the switching frequency is improved, the actual switching frequency of a single control switch of the inverter is in a low range, large temperature rise is not caused, the effect of inhibiting the eddy current loss of a rotor is achieved, high-efficiency and ultra-high-speed operation control of a motor is achieved, and the use reliability of motor driving is improved.

The invention discloses a spacer cable clamp device comprising at least two spacer cable clamps; each spacer cable clamp comprises a cable clamp body and a cable clamp cover plate rotationally connected with the cable clamp body and can be matched with the cable clamp body for clamping a cable, and also comprises magnetic groups arranged on the cable clamp body and the cable clamp cover plate foradjusting the heat of the spacer cable clamp. The invention also discloses high voltage power transmission equipment including the abovementioned spacer cable clamp device. The spacer cable clamp device can reduce the heat of the spacer cable clamps, and thus the power transmission quality can be prevented from being affected by local overheating of the spacer cable clamps.