10 results about "Electromagnetic theory" patented technology

The invention discloses an aflatoxin B1 detection method based on a BIC terahertz metamaterial sensor, and designs a continuous domain bound state (BIC) terahertz metamaterial sensor based on an electromagnetic theory and a time domain finite difference method. Terahertz enhanced spectrums of aflatoxin B1 solutions with different concentrations are collected, and analysis finds that the amplitude of a transmission peak of aflatoxin B1 at about 1.5 THz is gradually reduced along with the increase of the concentration of the aflatoxin B1 solution, and the frequency of the transmission peak gradually moves to a low frequency along with the increase of the concentration of the aflatoxin B1 solution; a PLS and LS-SVM quantitative model of aflatoxin is established, analysis finds that the LS-SVM model has a better effect, and the detection limit of aflatoxin B1 is 2.04 * 10 <-7 > mu g / ml. By adopting the method disclosed by the invention, rapid, nondestructive and high-sensitivity detection of the aflatoxin B1 in the grains can be realized.

The application provides a laser ranging correction system and method in a dust environment in a limited space, and relates to the field of optical measurement technology. A laser power attenuation model and a wavelength change relationship in a dust environment are obtained based on Mie scattering and a multi-particle single scattering model; a power attenuation coefficient is obtained based on the power attenuation model and Lambert-Beer law to estimate an effective ranging range of the instrument; and a distance correction model in the dust environment is established based on the wavelength change relationship and Maxwell electromagnetic theory. When applied, dust is collected in the limited space and a particle size distribution spectrum is obtained; a concentration measuring instrument is arranged in the limited space to collect dust mass concentration in real time; dust mass concentration on a ranging light path is obtained by interpolating the dust concentration at arrangement points; the particle size distribution and the light path dust mass concentration are substituted into the attenuation model and the distance correction model to obtain a correction value to correct the measured distance, and finally the ranging accuracy of the laser range finder in a dust environment in a limited space such as a mine working face and a construction site is improved.

The present invention relates to a method for measuring transient electromagnetic (TEM) measurements of ground-to-borehole data using an electric dipole source. The method comprises: sequentially arranging multiple transmitting points at different depths in a borehole; placing two transmitting electrodes of the transmitting electric dipole source at the first transmitting point in the borehole; connecting a transmitter to a probe in the borehole, and feeding a current of a predetermined waveform and magnitude from the borehole wall to the earth through the transmitting electrode of the transmitting dipole source; arranging receiving points on the surface, measuring the tangential magnetic field component of the line connecting the borehole and the receiving points, and obtaining the transient electromagnetic attenuation response of the earth; varying the depth of the probe in the borehole to obtain the transient electromagnetic attenuation response of the transmitting source at different depths until all designed transmitting points have been measured; and calculating the apparent resistivity of the earth based on the maximum moments of the transient electromagnetic attenuation responses of the different transmitting points based on electric dipole transient electromagnetic theory. The apparent resistivity of the earth is obtained by differentiation, and this is used as an initial model for conducting earth resistivity inversion. The present invention enables rapid and high-resolution measurement of earth resistivity.

The embodiment of the application discloses a structural color design method and device based on a tensor completion algorithm, which comprises the following steps: obtaining spectral data and geometric data of a dielectric array constituting a structural color, and combining the spectral data and the geometric data into multi-dimensional tensor data, wherein the tensor data comprises a to-be-completed tensor and a complete tensor containing all known entries; applying an alternating least squares method to Tucker decomposition of the to-be-completed tensor according to the tensor data, so as to obtain a minimum rank tensor after tensor completion, which is the same as known entries in the to-be-completed tensor; and converting the minimum rank tensor into spectral data and geometric data to obtain corresponding structural color. Through the above method, the embodiment of the application can quickly and accurately design structural color, avoids complex electromagnetic theory, and improves the device design efficiency of a small number of features.

The application discloses a RCS recovery and compensation calculation method based on flexible metal mesh equivalent surface reconstruction, which comprises the following steps: collecting the structure of the metal mesh, the test scene, the fitting state parameters and the measured RCS original data, and forming a standardized parameter database after preprocessing; adopting an adaptive density triangular division algorithm to disassemble the complex curved surface into triangular facets, constructing an electromagnetic reflection model for each triangular facet, correcting the electromagnetic coupling effect of adjacent facets, and integrating the complete equivalent reflection surface; dividing the system error and random error of the RCS measurement, establishing an error calculation model through electromagnetic theory derivation and experimental data fitting, and determining the weight through the entropy weight method; adopting a hybrid compensation strategy to compensate the system error, the random error and the curved surface reconstruction error, and verifying the recovery accuracy and the curved surface adaptability after outputting the accurate RCS data. The method greatly improves the RCS recovery accuracy, can well adapt to the complex curved surface of equipment, and meets the high-precision engineering test demand.

The invention discloses an automatic measurement device for a Helmholtz coil magnetic field based on a Hall effect, particularly relates to the technical field of electromagnetic measurement, and solves the problem that point-by-point measurement mainly depends on manual operation of a Hall element in the prior art. The technical problems of extremely poor reliability and repeatability of a measurement result caused by the defects of low positioning accuracy, non-uniform manual speed, easiness in environmental interference of weak signals, time consumption in data recording and processing, easiness in errors and the like in the prior art are solved. According to the technical scheme, a stepping motor is adopted for driving, and submillimeter-level accurate positioning is achieved; through a high-precision amplifier and an anti-interference design, the measurement precision of weak signals is improved; a high-speed data acquisition card and an intelligent algorithm are integrated, and automation and visualization of data processing are achieved; according to the invention, an expandable automatic measurement platform is provided for experiment teaching, and students are helped to deeply understand fusion application of an electromagnetic theory and a modern measurement technology.

The invention provides a radar signal processing method based on polarization interference identification, and the method comprises the steps: decomposing a monochromatic wave in any polarization form into two orthogonal polarization components according to a polarization electromagnetic theory, employing a phase amplitude measurement method, and carrying out the polarization interference identification through a pair of polarization orthogonal antennas with equal phase centers, the radar wave polarization direction is indirectly measured by measuring the amplitude ratio and the phase difference of received signals of the two antennas, so that a set of complete polarization judgment technology implementation route is constructed. According to the method, the axial ratio, the ellipticity angle and the inclination angle of the ellipse are calculated according to the measured amplitude ratio and phase difference, and the polarization measurement error is calculated according to the calculation result, so that a set of complete polarization measurement technology implementation route is constructed. According to the invention, the polarization measurement function is realized through digital domain signal measurement and is carried out after intermediate frequency processing AD conversion, and the high-speed FPGA is adopted to process digital signals, so that a polarization judgment and polarization measurement process based on the high-speed FPGA is constructed.

The application discloses a displacement field coupled ohmic contact and a preparation method thereof, which comprises a substrate layer, a bottom gate, a gate dielectric layer and a heterostructure arranged on the substrate layer in sequence, a plurality of sources and drains, all of which are arranged on the surface of the heterostructure and connected by air bridges, and each drain is surrounded by a plurality of sources, a plurality of TSV through holes, each of which penetrates the heterostructure and reaches the bottom gate, and a TSV dielectric layer is arranged on the inner wall of the TSV through hole and an interconnection metal is arranged in the TSV through hole, a plurality of TSV lead-out gates, each of which is arranged on a TSV through hole and in contact with the interconnection metal in the TSV through hole, and the effective width of each source and drain and the distance between adjacent sources and between an adjacent source and a drain are determined by Maxwell electromagnetic theory. The application realizes displacement field transportation, so that the ohmic contact has higher stability and reliability.

The invention discloses a radio frequency front-end digital intelligence design method based on a model library. According to the method, a basic library of a radio frequency front end comprises an antenna, a transceiving assembly and a frequency conversion module, indexes are distributed through a model library and an electromagnetic theory, link modeling is carried out, a time domain model is generated through simulation after a link model is linked, back-end processing is facilitated, and a frequency domain model generated through simulation can be subjected to index goodness of fit comparison with a real object. According to the invention, the digital modeling of the radio frequency front-end performance benchmarking object is realized, the time domain model is formed, and the working efficiency is improved.

This invention discloses a brightness temperature simulation method for ice and snow environment observation, belonging to the field of image processing technology. The method includes: Step 1, constructing a physical model of ice and snow layers using the SMRT model, and setting the electromagnetic theory model and ice and snow microstructure of the SMRT model; Step 2, calculating the surface emissivity ε corresponding to the uplink radiation; Step 3, acquiring mixed pixels, correcting the surface emissivity of the mixed pixels to obtain the emissivity of the mixed pixels; Step 4, using the RTTOV model combined with ERA5 atmospheric profile data and near-surface parameters to generate the simulated brightness temperature for Arctic ice and snow environment observation. This ice and snow environment observation brightness temperature simulation method utilizes the SMRT model to simulate the transmission process of microwave radiation in multiple layers of snow, sea ice, and other media, allowing for a better understanding of the physical characteristics of snow and its impact on microwave signals. By effectively coupling the SMRT and RTTOV models, more accurate model support can be provided for remote sensing inversion of Arctic ice and snow environment parameters.