The invention belongs to the technical field of signalprocessing, and discloses a distance-Doppler domain high-resolution parameter estimation method based on FrFT. Firstly, a target echo multi-bright-spot signal model is constructed, and then a corresponding replica signal set is constructed in combination with a transmitting signal and a to-be-detected target speed range; then selecting an optimal order, and performing fractional order Fourier transform on the received echo signal, the transmitted signal and the replica signal; constructing a distance Doppler fuzzy matrix according to a fractional order domain convolution theorem; an unconvolution integral model is established, and a Richardson-Lucy deconvolution iteration formula is deduced; and finally, solving a high-resolution target scattering function by using an R-L algorithm, and extracting target parameters for estimation. According to the method, the distance, speed resolution and parameter estimation performance of a traditional algorithm on the extended target can be improved, and robustness is achieved.
The present invention relates to a polyamide resin in which an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus is 8.0 nm or less, and a UV-cut slope (dT / dλ) measured for a specimen having a thickness of 45 μm or more and 55 μm or less according to ASTM E424 is 0.25 or more in the range of 10% to 80% transmittance, and a polymer film and resin laminate using the same. In addition, the present invention relates to a polyamide resin with characteristic profile in which a small-angle X-rayscattering function obtained by irradiating the polyamide resin with X-rays having an energy of 10 KeV to 20 KeV using a small-angle X-ray scattering apparatus satisfies Equation 1 and Equation 2, and a polymer film and resin laminate using the same.
The present invention relates to the field of electronic materials, specifically to an aircraft de-icing / electromagnetic low-scattering compatible structure and a design method thereof. The present invention adopts a periodic high-wave-transmittanceelectric heatingimpedance network, conforms the impedance network to the wave-absorbing structure, and realizes high-wave-transmittance performance through patterned design of the impedance network; and by optimizing the key ice formation areas on the surface of the wave-absorbing structure to perform resistance control in partitioned areas, the purpose of zoned heating and concentrated heat adjustment is achieved, thereby achieving more targeted de-icing. The present invention can simultaneously realize the functions of electric heating de-icing and electromagnetic low-scattering, which can not only meet the needs of aircraft de-icing at high altitude or in cold environments, thereby protecting the flight safety of the aircraft, but also ensure that the aircraft's electromagnetic low-scattering function is not affected. It is expected to be applied to the safety protection and electromagnetic compatibility of future low-detectable aircraft, and become its important technical accumulation.
The invention relates to the technical field of diffractive optical elements, and discloses a four-point square diffractive optical element with a bottom stray lightscattering function, the four-point square diffractive optical element comprises a laser head body and a four-point square diffractive optical element body, the surface of the laser head body is provided with a control panel, and the surface of the laser head body is in threaded connection with a head cover; the four-point square diffraction optical element body is arranged in the head cover, and by arranging the auxiliary device, when the four-point square diffraction optical element body is installed, after the head cover and the laser head body are installed, the pressing assembly can press the outer ring base, positioning is achieved, and damage to the optical element is reduced; the outer ring base is matched with the inner heat conduction ring to separate the four-point square diffractive optical element body from the head cover, meanwhile, the inner heat conduction ring can conduct heat on the four-point square diffractive optical element body, the head cover through hole, the protruding block penetrating hole and the flowing space form a through airflow path, external air can directly make contact with the inner heat conduction ring and take away heat, and effective heat dissipation is achieved.
The embodiment of the invention provides a short-wave frequency shift modulation and probing integrated transmission method, device and equipment and a medium. The method comprises the following steps: preprocessing a transmitted signal to obtain a modulated signal; transmitting the modulation signal through a channel to obtain a receiving signal; performing frequency offset correction on the received signal, and performing symbol-by-symbol weighted soft information fusion processing on the received signal after frequency offset correction to obtain a fused signal; decoding the fused signal to obtain a decoded bit data sequence, and completing data transmission; performing coding, interleaving, mapping and frequency shift modulation on the decoded bit data sequence to obtain a copy sequence of the transmitted signal; determining a channel impulse response according to the transmitted signal and the replica sequence of the transmitted signal, and determining a channel scattering function based on the channel impulse response; the channel features are extracted based on the channel scattering function, channel detection is completed, fusion of communication and detection functions is achieved, and the data transmission capacity of a communication system and the reliability of signal transmission are improved.
The application discloses an imaging domain least square migration method and device, electronic equipment and medium. The method can comprise: acquiring a global space-varying scattering function, interpolating and reconstructing the global space-varying scattering function to generate a plurality of scattering function data volumes; calculating the spatial deconvolution of the plurality of scattering function data volumes according to a depth domain imaging volume through an MPI parallel strategy to obtain corresponding least square migration images; and reducing the least square migration images corresponding to the plurality of scattering function data volumes to obtain a final imaging result. The application encrypts the point spread function through the interpolation and reconstruction strategy, and further deconvolves the reconstruction to suppress discontinuous noise through multiple superimpositions to obtain higher imaging accuracy.
The application relates to a chemical short-range order measurement method and system based on an atomic pair distribution function, and the method comprises the following steps: performing a total scattering experiment on a polycrystalline powder sample to obtain total scattering data, a scattering function and an atomic pair distribution function; based on the total scattering data, an initial three-dimensional atomic structure model is constructed; further, the initial three-dimensional atomic structure model is fitted and reconstructed by taking minimization of a fitting goodness factor as a target, so that a three-dimensional atomic structure model after fitting and reconstruction is obtained; according to the three-dimensional atomic structure model after fitting and reconstruction, a radial distribution function and a bulk average distribution concentration are calculated, and a chemical short-range order parameter calculation cutoff is set according to a near-neighbor atomic cutoff distance; further, the probability of an atom finding other types of atoms under the calculation cutoff is calculated; and the chemical short-range order parameter is calculated based on the probability and the bulk average distribution concentration. Compared with the prior art, the application has the advantage of wide application scenarios.
The present application relates to a kind of multi-dimension gradual scattering light guide plate, processing method and backlight plate, and the light guide plate includes substrate layer and scattering function layer.Substrate layer and scattering function layer are closely adhered, and substrate layer and scattering function layer are respectively made of different light-transmitting material composite;Scattering structure is gradually distributed along at least two dimensions on the light guide plate, scattering structure penetrates substrate layer and scattering function layer, scattering structure is misaligned arrangement in adjacent column in plane, and misalignment amount is 1 / 2-2 / 3 of column spacing;Light guide plate includes light inlet end and light outlet end, in the direction of light outlet end towards light inlet end, the distribution density of scattering structure gradually increases, in the direction of substrate layer towards scattering function layer, the size of scattering structure gradually decreases.Scattering structure gradually increases along light inlet end to light outlet end density, gradually decreases along substrate layer to scattering function layer size, and misaligned arrangement in adjacent column spacing in plane, it is favorable to eliminate bright and dark stripe, let light emitting surface brightness distribution be more uniform.
This invention relates to the field of shortwave antenna communication channel testing and modeling technology, specifically to a method for measuring the angular power spectrum of an antenna in a shortwave skywavescenario. The method includes: the receiver performing a two-dimensional equally spaced angular scan within a preset azimuth and elevation range; establishing an angular power spectrum measurement equation based on the received signal power, antenna pattern, and noise power channel, using the scattering function; convolving this equation with the pattern to obtain the angular power spectrum within a single path; discretizing the single-path received power matrix and antenna pattern matrix in two dimensions, and then performing zero-plugging expansion on each; converting the discretized single-path received power matrix and antenna pattern matrix into two-dimensional frequency domain matrices, and determining the frequency domain ratio between the received power matrix and the antenna pattern matrix mapped to the angular domain using time-delay Doppler domain parameters. This invention improves the accuracy of angular power spectrum measurement in shortwave skywave channels while reducing the dependence of traditional empirical modeling methods on a single propagation assumption.
The invention discloses a transmission, reflection and scattering integrated three-frequency-band common-aperture array antenna. The array antenna comprises a transmission unit, a reflection unit and a scattering unit. The transmission unit adopts a receiving-transmitting structure, the receiving structure is composed of a single-layer plane Vivaldi structure and a multi-stage fan-shaped microstrip line, the transmitting structure is composed of a single-layer plane eight-wood structure and a differential microstrip line, and 2-bit phase regulation and control are realized by simultaneously regulating and controlling the direction of the multi-stage fan-shaped microstrip line and the line length of the differential microstrip line. The reflection unit adopts a quasi-I-shaped metal step, and 1-bit phase regulation is realized by rotating the quasi-I-shaped metal step by 90 degrees. Scattering units are obtained by double-split square rings according to periodicity, and 1-bit phase regulation and control are achieved through mirroring operation. The reflecting unit and the scattering unit are consistent in size, are integrated in the same area, and are arranged on the front surface of the common metal ground on the two sides of the receiving structure of the transmission unit, so that the integration of transmission, reflection and scattering functions of three frequency bands is realized under a common port surface.
The invention discloses a sensor for measuring scattered light of a water body, a sensing device, a system for measuring optical parameters of the water body and a method for measuring a scattering function of the water body, the sensor is used for sensing the light intensity of light entering the water body along a first straight line at each scattering angle, and the sensor is characterized by comprising a plurality of sections of optical fibers, each section of optical fiber receives an optical signal by using the exposed side surface of the core layer, and each section of optical fiber is located in the same plane perpendicular to the first straight line and is arranged corresponding to the same scattering angle; the sections of optical fibers are arranged at intervals along the first straight line direction and have the same sector angle relative to the first straight line; the sensing device comprises a sensor and a seat body; the system for measuring the optical parameters of the water body comprises a transparent container, a laser transmitting module, a signalprocessing module and the sensing device, according to the measurement method for the water body scattering function, the system for measuring the optical parameters of the water body is adopted to obtain the water body scattering function, scattered light in a large sector angle range in the same scattering angle can be well received, the obtained numerical value can better represent the optical characteristics of the water body, the measurement precision is high, the cost is low, and the benefit is high.
The invention belongs to the field of short-wave channel measurement, and particularly relates to a short-wave channel measurement clustering calculation method based on a scattering function, which comprises the following steps of: designing an LFM measurement signal frame structure aiming at time delay / Doppler resolution and a maximum measurement range; designing that a received signal is related to a local replica signal, and solving a channel scattering function by using fast Fourier transform; designing a composite calculation and clustering calculation measurement parameter definition, and calculating a single channel measurement result according to a channel scattering function; and screening single channel measurement results of the same link, time and frequency, and calculating statistical results of a mean value, a standard deviation and a median. According to the method, the LFM signal is taken as a measurement signal, the method has the characteristics of low peak-to-average ratio, high resolution and strong anti-interference capability, and meanwhile, LFM frame structures with different time frequency resolutions and maximum measurable ranges can be designed through theoretical analysis.
The invention discloses a method and device for measuring a complex scattering function of a radar target, and relates to the field of microwavestealth technology and active microwaveremote sensing, and the method comprises the steps: constructing a generalized radar equation represented by a complex voltage for a radar detection target; according to the generalized radar equation, fitting to obtain a relation curve of the amplitude and the distance of the complex scattering function and a relation curve of the phase and the distance; performing low-pass filtering processing on the relation curve of the amplitude and the distance and the relation curve of the phase and the distance; and for the relation curve of the amplitude and the distance after filtering and the relation curve of the phase and the distance after filtering, obtaining the amplitude and the phase of the complex scattering function at the infinite far field by adopting a polynomial fitting and limit taking method. According to the invention, the method can directly and accurately measure the complex scattering function of any small to-be-measured target (including a standard device), and does not need an RCS standard device with a known standard value in the measurement process.
The utility model discloses a multispectral water body attenuation and forward small-angle scattering measurement device, which is characterized by comprising a light source, a scatterer and a water body attenuation and forward scattering luminous flux detection module, wherein the light source comprises N collimation lasers and a laser output gating module; each collimating laser is transmitted or reflected by the laser output gating module after being subjected to electric control time-sharing gating, and then outputs a single-wavelength collimating working light source in a time-sharing manner; the single-wavelength collimation working light source is scattered by the scatterer to form scattered light in different directions; the water body attenuation and forward scattering luminous flux detection module comprises a scattered light receiving and converging hyperbolic convex lens, an optical filter and an area array CCD (Charge Coupled Device); scattered light is collimated and converged to a radial optical filter through a scattered light receiving and converging hyperbolic convex lens, and scattered light signals are attenuated by the optical filter according to the attenuation amount of the radial optical filter in proportion and then are incident to a photosensitive element of the area array CCD. According to the utility model, measurement of multi-wavelength multi-angle forward small-angle volume scattering functions is realized.
This invention relates to shortwave communication technology, and particularly to a shortwave MIMO channel modeling method based on multi-domain coordination of time-space-frequency-polarization-angle. The method includes: constructing a nonlinear array of transceiver antennas; determining the geometric relationships of element spacing, element velocity, distance from the reflector cluster to the antenna, and reflector cluster velocity based on three-dimensional vectors; establishing a path transmission delay characterization mechanism jointly determined by propagation distance, the number of inseparable multipath paths, and time-difference statistical characteristics; decomposing the distance from the element to the reflector cluster into time-space stationary and non-stationary terms; establishing a polarization matrix and performing amplitude-phase weighting on multipath components with different arrival and departure angles; obtaining the existence and disappearance states of the path over time based on the reflector cluster probability model combined with Markov processes; incorporating the influence of antenna polarization on channel amplitude into the channel expression; and generating impulse response and corresponding scattering functions using the obtained angular power spectrum, delaydomain model, and time-varying path state model. This invention improves the polarization adaptability of large-scale arrays to actual arrays.
The invention relates to a chemical short-distance ordered measurement method and system based on an atom pair distribution function, and the method comprises the steps: carrying out a total scattering experiment on a polycrystalline powder sample, and obtaining total scattering data, a scattering function and the atom pair distribution function; constructing an initial three-dimensional atomic structure model based on the total scattering data; further performing fitting reconstruction on the initial three-dimensional atomic structure model by taking minimization of the fitting high-quality factor as a target to obtain a three-dimensional atomic structure model after fitting reconstruction; according to the fitted and reconstructed three-dimensional atomic structure model, calculating a radial distribution function and a volume phase average distribution concentration, and setting chemical short-range ordered parameters according to a neighbor atom truncation distance to calculate truncation; further calculating the probability of finding other types of atoms under the calculation truncation of the atoms; and calculating a chemical short-range order parameter based on the probability and the volume phase average distribution concentration. Compared with the prior art, the method has the advantage of wide application scenes.
The application specifically relates to a deep-sea reverberation suppression method based on a generalized spatial filtering principle, which comprises the following steps: constructing a three-dimensional scattering function based on an incident grazing angle, a scattering grazing angle and a scattering azimuth angle; constructing seabedreverberation intensity received from a scatterer based on the three-dimensional scattering function; determining a peak moment of the reverberation intensity based on the attenuation characteristics of the seabed reverberation intensity; selecting a reverberation acoustic line at the peak moment and a target echo acoustic line, constructing an array reverberation copy vector according to the reverberation acoustic line, and constructing a target echo copy vector according to the target echo acoustic line; constructing a second-order cone programming model based on the reverberation copy vector and the echo copy vector, and solving the second-order cone programming model to obtain a generalized spatial filtering matrix; and suppressing the array reverberation signal by using the generalized spatial filtering matrix. The application considers the change of the reverberation characteristics caused by the uncertainty of the real marine environment, and has good robustness for the reverberation suppression method in the fluctuating deep-sea environment.