17 results about "Ac field" patented technology

Aspects of the present disclosure generally relate to a magnetic recording device comprising a magnetic recording head. The magnetic recording head comprises a main pole, the main pole comprising a contact recessed from a media facing surface (MFS) and a contact terminal coupled to the contact, a trailing shield disposed adjacent to the main pole, a spin torque oscillator (STO) device disposed between the main pole and the trailing shield, a leading shield disposed adjacent to the main pole, the contact being disposed over the leading shield, a first alternating current (AC) source coupled to the main pole and the contact terminal, and a second AC source coupled to the trailing shield and the main pole. The first AC source is configured to generate an AC field, and the AC field is configured to generate spin waves near the contact to transfer energy to the STO device.

The application discloses a kind of power grid grid interval maintenance state judging method, device, equipment and medium.The method comprises: obtaining the position information of circuit breaker in target ac field, string internal isolator and string external line switch, and sending position information to ac section loss discrimination device;According to position information and preset judging logic, the maintenance state of each device in target ac field is determined by ac section loss discrimination device, wherein the maintenance state includes circuit breaker maintenance state, converter unit maintenance state and line maintenance state.Through the method of the application, the maintenance state of electrical interval in flexible HVDC converter station can be judged in real time and accurately, avoiding the time difference and misoperation risk caused by manual operation, improving the reliability and accuracy of ac section loss discrimination device.In addition, the method does not depend on manual intervention, reduces the influence of human factors on system stability, improves the safety and stability of power grid operation.

The present invention relates to a nucleic acid nanomotor. The present invention further relates to a system comprising a nanomotor and a control unit configured to generate an alternating current for rotating said nanomotor. The present invention also relates to a method of rotating a rotor of a nanomotor with respect to a stator of said nanomotor. Furthermore, the present invention relates to a use of a nanomotor or a system as a turbine, propulsion, fluid mixer, energy storing device, machine applying mechanical force e.g. on a system coupled to said nanomotor, and / or in chemical synthesis.

To provide a measurement device and method capable of achieving higher sensitivity.SOLUTION: A high frequency magnetic field generator applies a microwave to a magnetic resonance member where an electron spin quantum state is varied corresponding to a measured AC field, and which can perform electron spin quantum operation with the microwave. The high frequency power source causes the high frequency magnetic field generator to generate the microwave. A light emission device emits excitation light to be radiated to the magnetic resonance member. A measurement control part controls the high frequency power source and the light emission device for applying the microwave and the excitation light to the magnetic resonance member at a prescribed measurement sequence. Especially, the measurement control part applies a pulse sequence of the microwave based on Hahn echo pulse sequence or dynamic decoupling to the magnetic resonance member. At the time, an inverse (1 / fLOCK) of a spin lock frequency of the pulse sequence of the above-mentioned microwave is different from a cycle (1 / fAC) of the measured AC field.SELECTED DRAWING: Figure 2

The application discloses an extra-high voltage converter station of an overlapping architecture, comprising a valve hall, a converter unit, a pole line unit, a starting loop, an AC field, a bridge resistance unit, a limiting resistance unit, a metal return line unit and a grounding pole outgoing line unit; the valve hall comprises a valve tower and a converter valve, the converter unit and the pole line unit are distributed on both sides of the valve hall to form a first layer architecture; the first layer architecture further comprises the metal return line unit, and the metal return line unit is arranged in the middle of the valve hall; the starting loop, the AC field, the bridge resistance unit, the limiting resistance unit and the grounding pole outgoing line unit form a second layer architecture; the starting loop and the AC field are arranged above the converter unit, and the starting loop is connected with the AC field; the bridge resistance unit, the limiting resistance unit and the grounding pole outgoing line unit are arranged above the pole line unit; the first layer architecture and the second layer architecture are connected through a support type platform. The application splits each region of the converter station, optimizes the space overlapping structure, improves the site utilization rate and saves the occupied area.

The invention discloses a three-dimensional alternating current electric field sensor signal optimization method and system for high-voltage transmission electricity verification, and relates to the technical field related to high-voltage electricity verification, and the method comprises the steps: constructing a three-dimensional orthogonal sensing array which comprises three groups of electrode pairs distributed along an x axis, a y axis and a z axis; a corresponding controllable conduction unit is arranged for each pair of electrodes, so that each pair of electrodes is switched between a first state and a second state; acquiring a first alternating-current electric field response signal and a second alternating-current electric field response signal; analyzing the first AC electric field response signal and the second AC electric field response signal; and the electric field space vector of the high-voltage power transmission line is formed through combination according to the alternating current electric field response enhancement signals of each pair of electrodes. The technical problems of sensor signal distortion and poor high-voltage power transmission electricity testing accuracy and reliability caused by poor long-distance weak electric field response capability, fuzzy electric field direction discrimination and environmental noise interference in the prior art are solved, and the technical effect of improving the high-voltage power transmission electricity testing accuracy and reliability is achieved.

A high-frequency magnetic field generator applies microwaves to a magnetic resonance member in which an electron spin quantum state changes in response to an AC field to be measured, and in which an electron spin quantum operation can be performed using microwaves. A high-frequency power supply causes the high-frequency magnetic field generator to generate microwaves. A light emitting device emits excitation light to be emitted onto the magnetic resonance member. A measurement control unit controls the high-frequency power supply and the light emitting device to apply microwaves and excitation light to the magnetic resonance member in a predetermined measurement sequence. In particular, the measurement control unit applies a Hahn echo pulse sequence or a pulse sequence of microwaves based on dynamic decoupling to the magnetic resonance member. At this time, the reciprocal (1 / fLOCK) of the spin lock frequency of the microwave pulse sequence is different from the period (1 / fAC) of the AC field to be measured.

Method for producing an at least partially amorphous metal, the method comprising the following steps: Heating a metal to a molten state; and Cooling the molten metal below its melting point, whereby the molten metal is subjected to an electric current during cooling, which is at least one of the following: electromagnetically induced in the molten metal by applying a magnetic AC field to the molten metal; and directly applied to the molten metal by at least one electrode that contacts the molten metal after the metal has reached its molten state; where cooling the molten metal includes reducing the temperature of the molten metal to ambient temperature.

The application provides a seawater motion magnetic field characteristic measuring device, which comprises a composite structure pipeline, an excitation system and a measuring system; the composite structure pipeline is used for improving the motion speed of seawater; the excitation system adopts square Helmholtz coils which are arranged on the upper and lower sides of the composite structure pipeline respectively and generate a uniform magnetic field between the coils, and the magnetic field direction is perpendicular to the cuboid pipeline; the measuring system adopts a ring-shaped magnetic core induction coil, the resonant frequency of the ring-shaped magnetic core induction coil is tuned to the fundamental wave frequency of a PWM square wave signal through parallel matching capacitors, the in-band output response is improved, and the out-of-band interference is suppressed; a preamplifier, an analog switch and a low-pass filter jointly constitute a phase-locked amplification circuit, the analog switch is controlled by a PWM signal, and the seawater motion magnetic field signal under the action of an alternating field is extracted from the interference environment.

The invention relates to the technical field of black-start auxiliary excitation, in particular to a black-start auxiliary excitation circuit and a wire connecting device. The system comprises an excitation silicon controlled rectifier bridge, an alternating current magnetic field circuit breaker and a direct current magnetic field circuit breaker which are electrically connected with the excitation silicon controlled rectifier bridge, an excitation transformer electrically connected with the alternating current magnetic field circuit breaker, and a generator and an alternating current branch which are electrically connected with the excitation transformer, the device comprises an AC power switch electrically connected with the excitation silicon controlled rectifier bridge, an excitation transformer electrically connected with the AC power switch, a first diode rectifier bridge electrically connected with the excitation transformer, and an auxiliary excitation control switch electrically connected with the first diode rectifier bridge. According to the black-start auxiliary excitation circuit, the problem that a conventional direct-current power supply cannot be adopted for auxiliary excitation in the excitation black-start process of a large generator set is solved, and the installation and maintenance efficiency of the black-start auxiliary excitation circuit is improved.

The application relates to a switching selection control method and system of a split-ring AC system filter, priority initial values of input and removal sequences of each group of filters are set; when a group of filters needs to be selected to be input, a filter with the highest input priority in the filter in a state capable of being input is selected to be input, the input filter is set to have the lowest removal priority, and the removal priorities of other filters are improved by one level; when a group of filters needs to be selected to be removed, a filter with the highest removal priority in the filter in a state capable of being removed is selected to be input, the input filter is set to have the lowest input priority, and the input priorities of other filters are improved by one level. The application avoids the phenomenon that filters in a field are removed or input in a short time when an AC field bus tie circuit breaker is tripped and split-ring operation is switched from loop operation, avoids the situation that a certain AC filter is unavailable, loop operation mode cannot input or remove filters for reactive power control, and ensures normal operation of a DC system.

Aspects of the present disclosure generally relate to a magnetic recording device comprising a magnetic recording head. The magnetic recording head comprises a main pole, the main pole comprising a contact recessed from a media facing surface (MFS) and a contact terminal coupled to the contact, a trailing shield disposed adjacent to the main pole, a spin torque oscillator (STO) device disposed between the main pole and the trailing shield, a leading shield disposed adjacent to the main pole, the contact being disposed over the leading shield, a first alternating current (AC) source coupled to the main pole and the contact terminal, and a second AC source coupled to the trailing shield and the main pole. The first AC source is configured to generate an AC field, and the AC field is configured to generate spin waves near the contact to transfer energy to the STO device.

The invention relates to the field of antiferroelectric ceramic materials, and discloses a lead-free antiferroelectric ceramic, a preparation method and application thereof, the chemical composition of the ceramic is (1-x-y) NaNbO3-xABO3-yLa2O3-zMnO2, A is one of Ca, Sr and Ba, B is one of Hf, Zr, Sn and Ti, x is more than or equal to 0.1 and less than or equal to 0.2, y is more than or equal to 0.05 and less than or equal to 0.1, and z is more than or equal to 0.01 and less than or equal to 0.03; the ceramic is sodium niobate-based antiferroelectric ceramic, and the capacitance density of the ceramic is increased along with the increase of the external electric field intensity (0-20 kV / mm). According to a pulse capacitor element made of the ceramic, under the condition of an alternating current and direct current coupling electric field (the alternating current electric field is 8-10 kV / mm, and the direct current electric field is 18-20 kV / mm), the variation amplitude of the maximum capacitance density of the ceramic is smaller than 8% along with the increase of the working temperature, and the temperature stability of the lead-free antiferroelectric ceramic is remarkably improved.

The application discloses a kind of offshore wind power DC grid-connected converter station, including AC field, converter valve hall, bridge arm reactor and starting area, DC circuit breaker and energy consumption valve hall and DC field, AC field, converter valve hall, bridge arm reactor and starting area, DC circuit breaker and energy consumption valve hall and DC field are sequentially connected to make submarine cable by AC field access to the DC field DC transmission line transmission.The application can not need to set offshore converter station, offshore wind power AC power collection line is directly landed and converted into DC by converter station, and is accessed into DC power grid by DC line.

The invention discloses a multi-physics field calculation method for an offshore flexible direct current conversion platform and a related device, and relates to the technical field of high-voltage direct current transmission. The converter platform is divided into a valve hall, an alternating-current field hall, a direct-current field hall and a GIS equipment room according to functions, three-level calculation levels of equipment, a cabin and a platform are set, equipment-level, cabin-level and platform-level multi-physical field simulation is carried out in sequence, the simulation result of the previous level serves as the excitation condition of the next level, step-by-step geometric simplified modeling is combined, and the simulation result of the next level serves as the excitation condition of the next level. And cross-scale electricity-magnetism-heat-force multi-physics field coupling analysis is realized. The problems that in the prior art, due to the fact that the model scale is too large, full-platform simulation is not feasible, and key coupling variables are difficult to identify are solved, the simulation efficiency and precision are remarkably improved, and multi-physics field equilibrium optimization design in a compact space is supported.

To provide an electrode system for use in an AC-electrospinning process.SOLUTION: An electrode system comprises a charging-component electrode and at least one of an AC-field attenuating component and a precursor-liquid attenuating component. The charging-component electrode is electrically coupled to an AC source that applies a predetermined AC voltage to the charging-component electrode. When the electrode system includes the AC-field attenuating component, the AC-field attenuating component attenuates the AC field generated by the charging-component electrode to better shape and control the direction of fibrous flow. When the electrode system includes the precursor-liquid attenuating component, the precursor-liquid attenuating component serves to increase fiber generation even when a top surface of a liquid precursor is not ideally shaped or is below a rim or lip of a reservoir that contains the liquid on the charging-component electrode.SELECTED DRAWING: Figure 12A

The invention discloses a method and device for judging the state of a high-voltage direct-current power transmission system and a medium, and the method and device have the following beneficial effects: in the process of judging the operation state of alternating-current field equipment in the step S1, the circuit quantity of a line is compared with a preset current threshold value; the operation state of the line is further judged according to the comparison result, and whether the line forms an actual energy circulation loop or not is monitored, namely, whether the line forms the actual energy circulation loop or not can be judged by adding the auxiliary judgment condition that whether the line is in the operation state or not; therefore, misjudgment of the last circuit breaker and the last circuit by the control system in the empty charging state is well avoided.