74 results about "Electric field amplitude" patented technology

A method for controlled source electromagnetic Earth surveying includes deploying a plurality of electromagnetic sensors in a selected pattern at the top of an area of the Earth's subsurface to be surveyed. At least one of a transient electric field and a transient magnetic field is applied to the Earth in the vicinity of the sensors at a plurality of different positions. At least one of electric field amplitude and magnetic field amplitude at each of the sensors is recorded each time the transient electric field and / or magnetic field is applied. Each recording is adjusted for acquisition geometry. An image is generated corresponding to at least one sensor position using at least two stacked, adjusted recordings.

A method for determining whether the relative position of electrodes used by a neurostimulation system has changed within a patient comprises determining the amplitude of a field potential at each of at least one of the electrodes, determining if a change in each of the determined electric field amplitudes has occurred, and analyzing the change in each of the determined electric field amplitudes to determine whether a change in the relative position of the electrodes has occurred. Another method comprises measuring a first monopolar impedance between a first electrode and a reference electrode, measuring a second monopolar impedance between second electrode and the reference electrode, measuring a bipolar impedance between the first and second electrodes, and estimating an amplitude of a field potential at the second electrode based on the first and second monopolar impedances and the bipolar impedance.

A marine electromagnetic sensor cable includes a plurality of sensor modules disposed at spaced apart locations along a cable. Each module includes at least one pair of electrodes associated with the module. The electrodes are arranged to measure electric field in a direction along the direction of the cable. The cable is arranged to form a closed pattern. Another marine electromagnetic sensor cable includes a plurality of sensor modules disposed at spaced apart locations along a cable. Each module includes at least one pair of electrodes associated therewith. The electrodes are arranged to measure electric field in a direction along the direction of the cable. A plurality of spaced apart magnetic field sensors is associated with each module and arranged to enable determining an electric field amplitude in a direction transverse to the direction of the cable from magnetic field gradient.

A method for sensing an electric field includes processing digitized electric field signals, e.g., from an electric field sensing probe. The processing may include performing a Fast Fourier Transform of the digitized electric field signals to provide an indication of the magnitude of the electric field, and may include processing the digitized electric field signals at a rate that is related to the speed at which a movable sensing probe is moving. The method may include performing unweighted and / or weighted averaging in relation to processing electric field data, setting a comparison threshold, providing a human perceivable indication, or a combination of the foregoing.

The invention relates to a lightning monitoring and early warning method and system. The method comprises the steps of S1, detecting atmosphere average electric fields, optical radiation signals, electric field changing signals, magnetic field changing signals and GPS satellite signals of an area to be monitored and conducting signal conditioning and conversion, S2, judging whether the electric field changing amount meets preset triggering conditions or not according to the electric field changing signals, conducting signal collection and storage and executing the step S3 if the electric field changing amount meets the preset triggering conditions, and refreshing and awaiting if the electric field changing amount does not meet the preset triggering conditions, S3, conducting waveform characteristic extraction on the collected optical radiation signals, the collected electric field changing signals and the collected magnetic field changing signals, conducting cloud-to-ground lightning identification and location according to extracted characteristic parameters, and meanwhile storing and displaying the position of lightning in a geographic information system, the lightning time and waveforms of the optical radiation signals, the electric field changing signals and the magnetic field changing signals in the lightning process, and S4, generating early warning results according to cloud-to-ground lightning identification and location results and atmosphere average electric field amplitudes, and giving an warning signal according to the early warning results.

The invention discloses a terahertz time-domain spectrograph capable of entering at a fixed angle and simultaneously detecting transmission and reflection and belongs to the technical field of spectrums. The spectrograph is characterized in that a femtosecond laser device is used as an excitation source, and a beam splitter arranged at the output end of the femtosecond laser device is used for splitting one beam of laser into two beams, wherein one beam is detection light; the other beam is further split into two beams through a beam splitting prism, wherein one beam is used as pumping light and the other beam is also used as the detection light; the pumping light is gathered on a terahertz transmitter and pulse terahertz waves are generated by radiation; the generated terahertz waves are used for irradiating a sample; the terahertz waves transmitting the sample are focused on one path of terahertz detector, and the terahertz waves reflected by the sample are focused on the other path of terahertz detector; the two paths of detection light are also focused on the two terahertz detectors at the same time, and pulse terahertz wave electric field amplitude values of transmission and reflection are calibrated. In the system, a relative position between a reflecting mirror and the sample is fixed, and a transmission spectrum and a reflection spectrum of the sample can be obtained at the same time, so that the transmittance and the reflectivity of the sample are accurately obtained, the reliability of data is guaranteed and experiment efficiency is also improved.

The invention relates to an MT denoising device which comprises an electromagnetic receiver, a magnetic induction sensor and a non-polarizable electrode group, wherein the electromagnetic receiver is placed on the ground; the magnetic induction sensor is placed on the ground in a direction parallel to an x axis or a y axis and connected with the electromagnetic receiver through a cable; the non-polarizable electrode group takes a coordinate system origin as a central point, is placed symmetrically along the y axis or the x axis and grounded, and comprises a first long pole pitch electric dipole and a first short pole pitch electric dipole; the first long pole pitch electric dipole is used for measuring amplitude data of a long pole pitch electric field, and the first short pole pitch electric dipole is used for measuring amplitude data of a short pole pitch electric field; and all non-polarizable electrodes are connected with the electromagnetic receiver through wires. The device is used for calculating the correlation coefficient and the standard deviation between the amplitude data of the long pole pitch electric field and the short pole pitch electric field, when the correlation coefficient is smaller than a set correlation threshold, electric field amplitude data with largest standard deviation are removed, the correlation coefficient is calculated repeatedly until the correlation coefficient is larger than or equal to the set correlation threshold, and near field interference data are effectively removed.

The invention discloses a terahertz time-domain spectrometer capable of variable-angle incidence and simultaneous measurement of transmission and reflection, and belongs to the technical field of spectrum. The spectrometer is characterized in that an output beam of a femtosecond laser is divided into two beams by a beam splitter, one beam is probe light, the other beam is divided into two beams through the beam splitter, one beam is pump light, the other beam is also probe light, the pump light is collected to a terahertz emitter to generate terahertz waves, the terahertz waves respectively reach two terahertz detectors through sample transmission and reflection, two channels of probe light are respectively collected to the two terahertz detectors, and transmission and reflection terahertz wave electric field amplitudes are calibrated; the terahertz emitter and the two terahertz detectors are both arranged on a circular rail with scales, and the positions of the terahertz emitter and the terahertz detectors are adjustable; and a sample frame is fixed at the position of the center of circle of the rail so that transmission and reflection spectrums of a sample in different angle incident conditions can be measured through adjustment of relative positions of the terahertz emitter and the terahertz detectors with the sample.

The application relates to a lightning forecasting method and system. The method comprises the steps of reading the latest electric field station observation data and radar observation data of an electric field station, and establishing a lightning proximity prediction model according to the electric field station observation data and the radar observation data; the establishing of the lightning proximity prediction model comprises the following steps: step a: setting an electric field amplitude threshold and an electric field difference threshold; step b: judging whether the read electric field station observation data reaches the set electric field amplitude threshold or the electric field difference threshold, and if the electric field station observation data reaches the set electric field amplitude threshold or the electric field difference threshold, performing step c; step c: determining whether the radar observation data before the current time reaches the preset threshold, ifthe radar observation data reaches the preset threshold, performing step d; and step d: generating a lightning warning graphic product and issuing lightning warning. The application realizes the beforehand release of thunderstorm early warning, and raises the capability and level of lightning forecast.

A marine electromagnetic sensor cable includes a plurality of sensor modules disposed at spaced apart locations along a cable. Each module includes at least one pair of electrodes associated with the module. The electrodes are arranged to measure electric field in a direction along the direction of the cable. The cable is arranged to form a closed pattern. Another marine electromagnetic sensor cable includes a plurality of sensor modules disposed at spaced apart locations along a cable. Each module includes at least one pair of electrodes associated therewith. The electrodes are arranged to measure electric field in a direction along the direction of the cable. A plurality of spaced apart magnetic field sensors is associated with each module and arranged to enable determining an electric field amplitude in a direction transverse to the direction of the cable from magnetic field gradient.

Methods and apparatus for sensing or measuring an electromagnetic field. The method entails excitation into a distribution of Rydberg states of atoms of a gas occupying a test volume coextensive with the electromagnetic field. Transmission along a path traversing the test volume of at least one probe beam of electromagnetic radiation is measured at one or more frequencies overlapping a spectral feature, and a physical characteristic of the electromagnetic field is derived on the basis of variation of the spectral feature. In various embodiments, the electromagnetic field may be place in interferometric relation with another electromagnetic field. Time-varying electric field amplitude, frequency, phase and noise spectral distribution may be measured, and thus AM and FM modulated fields, as well as magnetic fields of about 1 Tesla. The apparatus for measuring the electromagnetic field may be unilaterally coupled to a probe field and detector or array of detectors.

A solid-state image sensor comprises a pixel unit having a substrate including therein a photoelectric conversion section and an optical waveguide arranged on a light incident side of the substrate so as to guide an incident light converted into a guided mode of the optical waveguide and being propagated through the optical waveguide to the photoelectric conversion section. The optical waveguide has a mode conversion section for changing a propagation state of the incident light such that the incident light being propagated through the optical waveguide has an electric field amplitude distributed with the same sign at a light incident surface of the substrate.

A method for accurately solving wind turbine blade echoes is provided, in order to obtain accurate blade echoes. The method mainly comprises three parts: firstly, solving two-dimensional backscattering field data of wind turbine blades within a range of a certain frequency band and a certain corner angle; secondly, according to the obtained two-dimensional backscattering field data of the blades,calculating an autocorrelation covariance matrix, and solving electromagnetic scattering electric field amplitudes and space coordinate parameters of the blades; and thirdly, establishing a blade equivalent model according to the obtained electric field amplitudes and space coordinate parameters, and deriving an equivalent model-based blade echo expression, so as to solve the blade echoes. The method provided by the present invention can be used to accurately solve the blade echoes and to realize the blade echo filtering on the radar side in actual engineering, and has significance to solve the passive interference of the wind turbine to the adjacent radar station.

The invention discloses an antenna radiation characteristic acquisition method based on phase-free near-field measurement. The method comprises the following steps: firstly, acquiring electric field amplitude information of all sampling points on a closed curved surface in a near-field region which is not far away from an antenna to be measured, and then establishing two nonlinear relationships between electric field distribution on a certain spherical surface of the near-field region and amplitude data on a measurement surface through a spherical wave expansion theory; and finally, speculating electric field distribution on the target spherical surface of the near-field region by using a genetic algorithm; when the algorithm stops iterative optimization, the tangential electric field distribution of the spherical surface to be guessed being basically close to an ideal result, at the moment, calculating a weighting coefficient on the spherical surface to be optimized by utilizing a spherical wave mode expansion theory, and obtaining a far field through spherical surface near-far field transformation. The invention provides a technology suitable for measuring antennas of various specifications.

The invention discloses an antenna near-field no-phase measurement method, wherein multiple near fields of a to-be-measured antenna can be accurately reconstructed through measuring an electric field amplitude value of a near-field scanning surface without direct measurement of phase information, and furthermore a far field directional diaphragm characteristic of the to-be-measured antenna is obtained. The antenna near-field no-phase measurement method aims to overcome the influence of the phase error to a measurement result in traditional near-field amplitude and phase measurement in a high-frequency working condition, and is a low-cost high-precision solution for near field measurement and aperture field diagnosis of high-frequency working antennae such as millimeter wave / submillimeter wave antenna and tera-hertz antenna.

The invention provides a terahertz spectrum analyzer which comprises a laser, three optical fiber couplers which are a first optical fiber coupler, a third optical fiber coupler and a fourth optical fiber coupler, an optical switch, a frequency shift ring, three optical delay lines which are a second optical delay line, a third optical delay line and a fourth optical delay line, a photoelectric detector, two photoelectric converters with terahertz detection antennas, two terahertz focusing elements and a terahertz optical splitter. In the acceleration of a terahertz electric field, photon-generated carriers are in accelerated motion to generate current which is proportional to the electric field amplitude of a terahertz wave, current is measured respectively, then square and sum are calculated, the radiation power of the terahertz wave is obtained, the frequency of the terahertz wave is obtained from the time sequence of the current, and the spectrum of the terahertz wave can be obtained. The terahertz spectrum analyzer has the advantages of wide spectral range, high spectral resolution and important scientific significance and application value and works at a room temperature.

The invention discloses an antenna near-field measurement method using an interpolation algorithm. The method comprises the steps: S10, collecting and recording electric field amplitude and phase information on a near-field scanning surface of the antenna to be measured, wherein the near-field scanning surface is in any curved surface shape and needs to meet the following three conditions at the same time. S20, interpolating the electric field amplitude on the near-field scanning surface of the antenna to be measured through cubic spline interpolation. S30, interpolating the electric field phase on the near-field scanning surface of the antenna to be measured through bilinear interpolation. S40, calculating a far-field electric field of the to-be-tested antenna according to a Huygens equivalence principle based on the near-field electric field amplitude and phase value of the to-be-tested antenna obtained by interpolation. and S50, based on the calculated far-field electric field of the to-be-tested antenna, calculating a far-field normalized directional diagram of the to-be-tested antenna. The near-field scanning surface in the method is not limited to a plane, a cylindrical surface and a spherical surface, and can be changed into any curved surface according to the actual measurement environment change.

A method of examining a configuration of a sample includes the step of irradiating a terahertz pulsed light, which possesses a wavelength to transmit through the sample, to at least two different portions of the sample, the step of detecting at least two electric field amplitude-time resolved waveforms of the terahertz pulsed light transmitted through the first and second portions of the object to be examined, and the step of examining the configuration of the sample based upon phase information obtained from the electric field amplitude-time resolved waveforms detected.

The embodiment of the invention discloses a nonlinear nanoantenna scattering directivity control method, device and equipment, and a computer readable storage medium. The method comprises the steps: adding a plane electromagnetic wave to a dimer nanoantenna which is formed in a manner that first dielectric material particles and nonlinear graphene wrap second dielectric material particles, and calculating dynamical nonlinear equations for describing the electric dipole moment of the dimer nanoantenna; calculating the dipole scattering intensity of the dimer nanoantenna according to the nonlinear equations; Adjusting the geometric parameters of the dimer nanoantenna and the conductivity parameter of graphene to enable the dipole scattering of the dimer nanoantenna to be in a bistable stateunder the preset frequency of the plane electromagnetic wave, adjusting the electric field amplitude of the plane electromagnetic wave applied to the dimer nanoantenna, so as to enable the scatteringstate of the dimer nanoantenna to be switched between a first directional scattering state and a second directional scattering state. According to the invention, the method achieves the controllable operation of the scattering direction of a nonlinear optical nanoantenna in a time evolution process.

The invention discloses a satellite-borne four slot feeding four-arm helical antenna comprising four helical antennas, a Balun electrically connected with the four helical antennas and a metal bottomboard used for supporting the Balun, wherein the Balun comprises an external conductor of a hollow structure, and an inner conductor coaxially arranged in the outer conductor; four slots are formed inthe top of the external conductor along axis directions, used for achieving equal electric field amplitude on the four helical antennas, and phases which sequentially differ by 90 DEG from one another, the external conductor is divided into four external conductor units by the four slots, and the internal conductor is electrically connected with the first external conductor unit in the four external conductor units; a data receiving port is arranged at the bottom of the external conductor, the metal bottom board is provided with a through hole, the position of the through hole is corresponding to the data receiving port, and the through hole is used for holding a data receiving device. The four arms of the four-arm helical antenna only forms an antenna pattern, without performing phase control; the Balun generates the phase difference needed by the four arms of the antenna, and the design difficulty of the four-arm helical antenna is reduced.

The invention discloses a device and method for simultaneously measuring the topological charge size and positive and negative values of a vortex light beam. The device comprises an angular gradual-change attenuation piece which is used for the angular modulation of the amplitude of an electric field of a to-be-measured vortex light beam; a focusing lens which is used for focusing the modulated vortex light beam; and a CCD camera that is used for recording the focusing light intensity and obtaining the size and positive and negative information of the topological charge of the vortex beam to be measured through the distribution of the focusing light intensity. By means of the technical scheme, simultaneous measurement of the topological charge and the positive and negative values of the vortex beam to be measured is realized.

The invention discloses a polarization-reconfigurable high-power microwave feed source. The polarization-reconfigurable high-power microwave feed source comprises a tank body which is internally vacuumized, wherein a combination of a corrugated horn, two phase correcting mirrors and two circular polarization gratings is adopted in the tank body; a polarized wave beam in a left spiral direction / right spiral direction / any polarization direction can be output according to the needs; section amplitude and phase distribution of the output wave beam can be controlled through the design of the phase correcting mirrors. The polarization-reconfigurable high-power microwave feed source is compact in structure, the polarization state of the output wave beam can be converted according to the needs, and section electric field amplitude and phase distribution of the wave beam can be designed, and the polarization-reconfigurable high-power microwave feed source can be widely applied to the fields of a high-power microwave emitting system, a laser emitting system, and the like.

The invention discloses a waste oil emulsion chaotic frequency pulsed electric field demulsification method and system. Firstly, a fixed-amplitude and equal-pulse-width frequency chaotic high-voltagepulsed electric field is generated by regulating and controlling the chaotic pulse frequency, the frequency in the frequency chaos comprises the resonant frequency of the emulsified liquid drops, andthen the frequency chaos high-voltage pulse electric field acts on the waste oil emulsified liquid for demulsification and dehydration. The invention provides the waste oil emulsion chaotic frequencypulsed electric field demulsification method. Aiming at the characteristics of demulsification and dehydration of a pulsed electric field, a fixed-amplitude and equal-pulse-width chaotic frequency electric field method is applied. The defect that a common constant pulse electric field cannot cover the resonant frequency of liquid drops in the emulsified oil is overcome, fixed amplitude and equal pulse width can avoid influence on demulsification efficiency due to uncertainty of electric field amplitude and pulse width, the pulse rate is chaotic, adjustable and controllable, full coverage of emulsion droplet electric field resonant frequency can be realized, the maximum efficiency of electric field demulsification is brought into play, and the requirement of efficient demulsification and dehydration in the industrial waste oil recycling process is met.

The invention discloses a high-nonlinearity optical fiber coupling crosstalk detection method, which comprises the following steps: dividing an optical fiber into equal-length sections, determining the electric field amplitude of each section, obtaining the electric field amplitude of the tail end of each section of the optical fiber, obtaining the coupling power of each section, evaluating the inter-core crosstalk of the whole optical fiber, determining the section length value through simulation, and introducing the nonlinearity characteristic; and observing the crosstalk change during the period, solving to obtain the electric field amplitude of each section where the nonlinear characteristic is introduced, calculating the threshold power and the critical power of the nonlinear coupler, and calculating the length of the nonlinear interaction according to the threshold power and the critical power of the nonlinear coupler. According to the method, the coupling mode theory is expanded to the nonlinear field from the sectional idea, the solution of the coupling mode equation of the nonlinear directional coupler (NLDC) is provided, and the inhibition effect of nonlinearity on linear coupling crosstalk is verified in a numerical solution simulation mode.