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2689 results about "Narrow band" patented technology

Generally, narrowband describes telecommunication that carries voice information in a narrow band of frequencies. More specifically, the term has been used to describe a specific frequency range set aside by the U.S. FCC for mobile or radio services, including paging systems, from 50 cps to 64 Kbps.

Wind generating set fault monitoring method and system based on voiceprint recognition

The invention provides a wind generating set fault monitoring method and system based on voiceprint recognition, and the method comprises the steps: collecting gear box voiceprint signal data in real time, recording signal fluctuation caused by gear surface wear, and obtaining an original signal data set containing a frequency spectrum high-frequency component enhancement feature; a time-frequency analysis method is adopted for the original signal data set, non-linear interference of vibration signals is recognized, multi-scale decomposition is carried out, initial wear frequency spectrum narrow-band characteristics and medium-term harmonic components are separated out, and a frequency spectrum component set is obtained; extracting characteristic parameters related to modulation depth abnormal fluctuation from the frequency spectrum component set, identifying a gear pair meshing frequency change rule, and determining a distribution mode of a tooth surface contact noise proportion; and if the feature matching result shows that the deviation between the spectrum high-frequency component diffusion distortion feature and the reference feature library exceeds a threshold value, adding the tooth surface fatigue crack noise feature into the feature library to obtain a target feature library.
Owner:GUANGDONG ZHONGHUI ZHIWEI ENERGY MANAGEMENT CO LTD

Online detection method and system for laser-induced damage of optical lens

The invention relates to the technical field of optical lens defect detection, and particularly discloses an optical lens laser-induced damage on-line detection method and system, a linear polarizer and a narrow-band filter are connected in series in a detection laser light path, non-target polarized light is filtered through polarization direction matching, meanwhile, interference of the environment and scattered light is inhibited through the narrow-band filter, and the laser-induced damage on-line detection system is obtained. According to the method, external source noise such as ambient light and non-target polarized light is reduced through polarization matching and narrow-band filtering, randomness of speckle noise is offset through multi-angle collection and signal fusion in a visual detection mode, exposure is dynamically adjusted, an image is fused to improve the signal-to-noise ratio, noise and real signals are decoupled through self-supervised learning, and the real-time performance of the system is improved. Dust interference is removed in combination with morphological operation; a deep learning reasoning model enhances the damage identification capability in a noise environment, defocusing blur caused by mechanical vibration is eliminated through phase conjugate correction, and the influence of photoelectric conversion noise, dust interference and the like on the detection efficiency and accuracy is remarkably reduced through multi-link linkage.
Owner:NANJING BENZE OPTOELECTRONICS TECH CO LTD

High-resolution small-angle measurement reference device based on laser frequency measurement

The invention provides a high-resolution small-angle measuring device based on laser frequency measurement, which comprises a laser generating device, a reflecting mirror group and a beat frequency measuring module, and is characterized in that a narrow-band interference sheet (3) and a transparent solid medium (4) are fixed on a high-precision horizontal rotating table (5); the fixing positions of the narrow-band interference sheet (3) and the transparent solid medium (4) are axially symmetric and are not parallel to each other by taking the diameter, perpendicular to the light path, of the rotating table as the axis; and when the high-precision horizontal rotating table (5) rotates to cause the frequency change delta f of the measured laser, the variable quantity of the beat frequency is equal to delta f. According to the small-angle measuring device, angle measurement is converted into frequency measurement by means of the high sensitivity of laser frequency to the rotation angle of the transparent solid medium, and the cavity mode frequency and the transmission frequency of the interference piece are synchronously changed by adding the interference piece; the problem that the tunable range of laser frequency is small due to rotation of a transparent solid medium is solved, and continuous measurement of micro angles is achieved.
Owner:NANJING UNIV OF POSTS & TELECOMM

Thyroid intraoperative real-time navigation method and system based on multi-mode optical fusion

The invention discloses a thyroid intraoperative real-time navigation method and a thyroid intraoperative real-time navigation system based on multi-mode optical fusion. The thyroid intraoperative real-time navigation method comprises the following steps: outputting visible light through an endoscope and coupling light waves of a narrow-band multispectral light source to irradiate an operative field, exciting parathyroid glands to generate near-infrared fluorescence, and receiving reflected visible light, split light, near-infrared fluorescence and laser speckle signals through an endoscope probe. And separating the composite optical signal into four channels, and respectively generating an anatomical structure color image, a blood vessel spectroscopic image, a parathyroid gland near-infrared fluorescence image and a laser speckle image. Performing decorrelation processing on the laser speckle image to generate a blood flow dynamic pseudo-color decorrelation speckle image; an anatomical structure, a blood vessel center line, a parathyroid gland contour and blood flow dynamic feature points are extracted through a multi-modal registration technology, after affine transformation space alignment is conducted, a comprehensive imaging map containing the anatomical structure, blood vessel distribution and parathyroid gland function marking information is generated through a wavelet fusion algorithm, and intraoperative multi-dimensional real-time tissue navigation is achieved.
Owner:THE FIFTH AFFILIATED HOSPITAL OF GUANGZHOU MEDICAL UNIV

Ultra-low power consumption narrow-band filter implementation method based on digital phased array system

The invention relates to the technical field of narrow-band filters, and discloses an ultra-low power consumption narrow-band filter implementation method based on a digital phased array system, and the method comprises the following steps: S1, collecting input signal data, carrying out the adaptive preprocessing, and generating preprocessed signal data; s2, performing digital beam forming processing based on the preprocessed signal data to generate digital beam forming data; s3, performing narrowband filtering parameter matching processing according to the digital beam forming data to generate narrowband filtering parameter data; in the narrowband filtering processing process, disturbance of environmental electromagnetic interference to a target signal is identified and eliminated in real time through adaptive noise suppression and a multi-dimensional signal preprocessing mechanism, so that the system can guarantee the pointing precision of digital beam forming, the pointing offset problem in the space signal capturing process is avoided, the accuracy of narrowband signal extraction is improved, and the accuracy of narrowband signal extraction is improved. And the reliability of filtering output and the signal fidelity are enhanced.
Owner:XIAN QIANJING DEFENSE TECH CO LTD

Digital phase-locked amplifier based on frequency adaptive technology and weak signal acquisition system and method

The invention relates to a digital lock-in amplifier based on a frequency adaptive technology and a weak signal acquisition system and method, and the system comprises a front-end signal processing module which is used for obtaining a weak signal to be detected; the frequency self-adaptive tracking module is used for performing fast Fourier transform on the frequency of the weak signal to be measured to obtain the position of the maximum spectral line so as to synthesize a frequency control word, further generate a local reference signal and simultaneously adjust the coefficients of a low-pass filter and a loop filter and the series adjustment mode of a carrier synchronization ring; the multi-rate narrow-band low-pass filter module is used for multiplying the digital signal by a local reference signal and then carrying out filtering and down-sampling on a high-frequency signal to obtain a plurality of mutually orthogonal difference frequency components; the vector operation module is used for carrying out vector operation on the plurality of mutually orthogonal difference frequency components to obtain the phase and the amplitude in the weak signal to be measured; and the man-machine interaction module is used for displaying and storing the phase and the amplitude in the weak signal to be detected.
Owner:HUBEI UNIV

Real-time beam forming and interference reduction method for phased array computing terminal

The invention discloses a phased array computing terminal real-time beam forming and interference reduction method, which comprises the following steps of: 1, acquiring an observation signal by an observation target, calculating an independent narrow-band beam former for each sub-band channel for a channelized frequency domain baseband signal, and further realizing frequency domain real-time beam forming on all baseband signals at the same time, based on the dynamic change of the propagation environment, the beam forming weight is updated, the beam shape and direction are adjusted, and the maximum signal-to-noise ratio beam forming is realized; and 2, effective interference reduction is realized by adopting spatial filtering in phased array calculation terminal equipment, a spatial filter is constructed in combination with a subspace projection method, identification and elimination of interference signals are realized through calculation and characteristic decomposition of a covariance matrix, and finally filtered signal data are obtained. According to the method, a large number of independent tasks in matrix operation can be efficiently processed, so that the calculation time is remarkably shortened, and the observation capability of a system and the adaptability of an application scene are improved.
Owner:NAT ASTRONOMICAL OBSERVATORIES CHINESE ACAD OF SCI

Photoacoustic spectrum-confocal Raman spectrum multi-view-field high-dimensional imaging method and device

The invention discloses a photoacoustic spectrum-confocal Raman spectrum multi-view-field high-dimensional imaging method and a photoacoustic spectrum-confocal Raman spectrum multi-view-field high-dimensional imaging device. Nanosecond pulse laser with adjustable wavelength is generated through a continuous spectrum nanosecond pulser and a narrow-band spectrum tuning module and cooperates with a microscopic detection module, a depth imaging module, a galvanometer system and an electric displacement table to obtain spatial three-dimensional data, a photoacoustic spectrum and a Raman spectrum under multiple view fields; shallow photoacoustic spectrum-Raman spectrum tomography and deep three-dimensional photoacoustic imaging are realized; correcting a photoacoustic spectrum quantitative error by using a spectrum decoupling algorithm, and fusing the multi-view-field data to generate multi-view-field high-dimensional photoacoustic spectrum-Raman spectrum data; high-dimensional data features are extracted based on a 3D convolution instance segmentation network, and quantitative analysis and spatial distribution visualization of blood oxygen, inflammatory factors and the like are achieved. According to the method, the limitation that substances are difficult to analyze in photoacoustic imaging is overcome, the contradiction between the imaging resolution and the penetration depth is solved, and an accurate analysis means is provided for diagnosis of diseases such as knee osteoarthritis and sepsis.
Owner:ZHEJIANG UNIV

Energy harvesting acoustic metasurface using piezoelectric transducers

The technology described herein is directed towards resonators that incorporate or are closely coupled to transducers from which energy is harvested. The resonators can be unit cells of a metasurface configured for narrowband sound absorption by phase cancellation of the acoustic wave Electroacoustic transducers such as piezoelectric transducers can be positioned, e.g., at the neck ports of the resonators, to generate electricity as the air pressure of incoming acoustic waves enters the unit cells. Energy can be harvested from the electricity, and stored for usage and / or used directly to power a device. Such a device powered by the harvested energy can change the resonant frequency of the device, e.g., by changing temperatures in the resonators' air cavities, changing respective dimensions of the respective air cavities, or changing the resonant frequency of the unit cells resonators by changing respective airflow in the respective air cavities.
Owner:DELL PROD LP

Passive metamaterials-based acoustic sound suppression modules for servers

The technology described herein is directed towards one or more modular metasurfaces arranged with unit cells for sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. The metasurfaces can be arranged in a modular frame structure of surrounding unit cells, positioned behind the server's fan(s), with an opening in the frame structure to facilitate airflow therethrough, without obstructing or substantially obstructing the airflow to the surrounding environment.
Owner:DELL PROD LP

Wideband / multiband add-on metasurface modules for enhanced noise suppression in server infrastructure

The technology described herein is directed towards modular metasurfaces arranged with unit cells for narrowband, wideband and / or multiband sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed in a server rack, proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Differently-dimensioned unit cells can be built into a single metasurface module, thereby facilitating wideband and / or multiband sound absorption with that metasurface. The modular metasurfaces can be attached to the sidewalls of a server rack, or positioned in otherwise empty slots above and below a server, optionally coupled to blanking panels for covering the openings of those slots.
Owner:DELL PROD LP

Spatial-wideband compensation in wideband massive MIMO systems

This invention provides a novel transceiver design to control / compensate for the spatial-wideband effect in wideband massive multiple-input multiple-output (MIMO) systems for both sensing and communication networks. The proposed design aims to divide the ultra-wideband signal into narrow band beams and control them with a simplified exhaustive search-based precoding to align the beam angle to the target direction.
Owner:ISTANBUL MEDIPOL UNIVERSITESI TEKNOLOJI TRANSFER OFISI ANONIM SIRKETI

Multi-source fusion spectrum cross-domain high-precision prediction method and system based on transfer learning

The invention provides a multi-source fusion spectrum cross-domain high-precision prediction method and system based on transfer learning. The method comprises the following steps: S1, acquiring spectrograms collected by a spectral imaging device under multiple wavelengths; s2, extracting various types of features from the spectrogram; s3, training a fusion model to obtain a trained fusion model; and S4, inputting a to-be-predicted spectrum into the trained fusion model, and outputting a result. According to the invention, 10 <-4 > nm-level wavelength prediction can be achieved in a common industrial camera system, and the level of a scientific research-level grating spectrometer (0.001-0.002 nm) can be reached / exceeded; on a narrow-band, middle-band and wide-band multi-scene cross-domain data set, the mean absolute error (MAE) can be reduced from the nanoscale to the magnitude of 10 <-4 > nm, and excellent robustness is kept under the conditions of noise, feature deficiency and few samples.
Owner:HONG KONG UNIV OF SCI & TECH (GUANGZHOU)

Cross-modal image fusion detection system for endoscopic early cancer lesion

The invention relates to the technical field of medical image processing, in particular to a cross-modal image fusion detection system for endoscopic early cancer lesions, which comprises a data acquisition module for acquiring a white light endoscope and a narrow-band imaging image; the data annotation module carries out pixel-level annotation, and the data enhancement module amplifies a data set by using CycleGAN; the white light data module and the narrowband data module train feature extraction models respectively; the feature alignment and attention module solves the problem that feature scales and semantics between two modes are inconsistent, and efficient fusion is achieved. The edge enhancement module enhances feature extraction of small focuses through the generative adversarial network; the fusion model construction module fuses the features and the transition area data to generate a fusion model; and the output module processes the white light and the narrow-band imaging image and outputs a fused image. Through feature alignment, an attention mechanism and a CyclGAN data enhancement technology, the problem of insufficient medical image data is effectively solved, the model generalization ability is enhanced, and efficient and accurate early cancer focus detection is realized.
Owner:杭州市第九医院

Broadband receiver ADC nonlinear spurious suppression method and device

The invention discloses a broadband receiver ADC nonlinear spurious suppression method and device, and relates to the technical field of instruments and meters, and the method comprises the following steps: receiving an intermediate frequency signal, carrying out the analog-to-digital conversion of the intermediate frequency signal, and obtaining a digital intermediate frequency signal, the intermediate frequency signal being obtained through the receiving of a superheterodyne architecture; the method comprises the following steps: reducing the signal bandwidth of a digital intermediate frequency signal by using a CIC extraction mode to obtain different signal bandwidths BW, and performing spectral analysis on the different signal bandwidths BW by using a fixed-point FFT to obtain corresponding resolution bandwidths RBW; on the premise that the cost of the receiver is not increased, spurious signals under the narrow-band instantaneous bandwidth are reduced, and the index of the receiver is improved.
Owner:ANHUI EGRETS ELECTRONICS TECH

Method for establishing grassland plant nitrogen content monitoring model based on remote sensing technology

The invention relates to the technical field of leaf nitrogen content estimation, in particular to a method for establishing a grassland plant nitrogen content monitoring model based on a remote sensing technology. The method comprises the following steps: controlling an unmanned aerial vehicle platform carrying a narrowband multispectral camera and a linear polarization camera, and collecting a spectral image sequence and a polarization image group at an observation window with a solar zenith angle of 30-40 degrees; extracting a reflectivity value of each wave band in the spectral image sequence, calculating a reflectivity first-order derivative and determining a red edge position offset; extracting horizontal and vertical polarization components in the polarization image group, calculating a polarization degree and constructing a polarization degree difference index; and identifying the center of the fecal spot by searching a pixel with a local maximum polarization degree difference index and red edge position offset blue shift exceeding a preset threshold value. According to the method, excrement spot recognition and remote sensing description of the nitrogen influence range thereof are achieved through double-index complementation of the red edge position offset and the polarization degree difference index.
Owner:河套学院

Deep learning-based shortwave signal detection, identification and training method, device and equipment, and storage medium

The invention discloses a short wave signal detection, identification and training method based on deep learning. The method comprises the following steps: extracting IQ data of a narrowband signal from target signal data through a deep learning model; the modulation features and protocol features of the narrowband IQ data are analyzed through a deep learning model, and signal modulation mode identification and signal protocol type identification are carried out; storing all processed signal data and related label information; labeling the signal data based on a deep learning model and a preset rule, and storing a finally confirmed label as a final labeling result in a database; and collecting labeled data from the database, performing learning model training and parameter adjustment based on a deep learning framework, and performing retraining by taking a first time interval as a period. The invention also discloses a short wave signal detection, identification and training device based on deep learning, corresponding equipment and a storage medium. According to the invention, the short-wave signal can be efficiently and accurately detected and identified.
Owner:WUHAN SHIP COMM RES INST (NO 722 RES INST OF CHINA STATE SHIPBUILDING CORP)

Coreset arrangement for narrowband new radio

Various techniques are provided for a method including triggering, by a user equipment (UE), a resource block (RB) offset allocation determination, detecting, by the UE, at least one of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) in a received synchronization signal (SS) block (SSB), reading, by the UE, a physical broadcast channel (PBCH) parameter and a signaled offset from a master information block of a PBCH of the SSB, determining, by the UE, an RB offset based on the PBCH parameter and the signaled offset, and determining, by the UE, a control resource set frequency location based on the RB offset.
Owner:NOKIA TECHNOLOGIES OY

Cable fault diagnosis method, system and terminal

The invention relates to the technical field of fault diagnosis, and discloses a cable fault diagnosis method, system and terminal, and the method comprises the steps: applying a broadband excitation signal to a target cable, so as to excite the target cable to generate a first response signal; extracting multi-dimensional time-frequency features of the first response signal after adaptive wavelet threshold denoising, and matching a fault template of a preset cable reference model according to energy distribution features in the multi-dimensional time-frequency features; determining a fault area in a fault template corresponding to the target cable according to the propagation time and the propagation speed of the first response signal; applying the narrowband excitation signal to a fault area of the target cable to obtain an impedance spectrum; the resonant frequency point based on the impedance frequency spectrum and the corresponding impedance amplitude value are compared with a typical fault mode in a fault feature database, and the fault type and the fault position of the target cable are obtained; generating a diagnosis report of the target cable according to the fault type and the fault position; the cable fault diagnosis accuracy can be improved.
Owner:HANGZHOU JUQI INFORMATION TECH CO LTD +2

Methods of narrowband physical random access channel preamble transmissions with orthogonal cover code multiplexing

An internet of things (IoT) non-terrestrial network (NTN) device user equipment (UE) is described. The UE includes receiving circuitry configured to receive narrowband physical random access channel (NPRACH) configurations including NPRACH resource configuration, repetition parameters, orthogonal cover code (OCC) multiplexing methods and OCC multiplexing factors. The UE also includes transmitting circuitry configured to select an NPRACH resource and randomly select an OCC index for an OCC multiplexing. The transmitting circuitry is further configured to transmit NPRACH preambles with a configured OCC multiplexing method and a multiplexing factor.
Owner:SHARP KK

Double-domain combined narrow-band radar moving target classification and identification method and related product

The invention discloses a double-domain combined narrow-band radar moving target classification and identification method and related products. Processing a target echo signal received by the radar to obtain a distance Doppler spectrum; obtaining a micro-Doppler time-frequency spectrum based on a target echo signal received by a radar; respectively cutting the distance Doppler spectrum and the micro Doppler time-frequency spectrum to obtain distance Doppler domain characteristic data and micro Doppler domain characteristic data; and inputting the distance Doppler domain feature data and the micro Doppler domain feature data into a pre-constructed RFICNet to obtain a target classification result. According to the method, dual-domain data features of the distance Doppler domain and the micro-Doppler domain are combined, the method does not depend on complex echo data preprocessing operation and excessive prior physical assumptions, dual-domain joint feature information can make up for the deficiency of feature basis during classification, and the classification recognition precision of the narrow-band radar moving target is improved.
Owner:XIDIAN UNIV

Solid waste-based zinc chloride preparation process control method and system

The invention discloses a solid waste-based zinc chloride preparation process control method and system, and relates to the technical field of zinc chloride preparation, and the method comprises the following steps: obtaining a unified time base line, establishing a bubble phase reference field, collecting a sound-induced echo sequence, a micro-pressure waveform sequence and a light scattering sequence of a reaction liquid under the bubble phase reference field, and calculating the solid waste-based zinc chloride preparation process. Fusing to generate a bubble density space-time matrix; and performing reversible time-frequency rearrangement based on the bubble density space-time matrix, decomposing to obtain different frequency band distributions, extracting a narrow-band resident bubble group, calculating critical volume distribution and collapse precursor indexes, and constructing a dynamic risk fingerprint database. According to the method, a unified time base line and a bubble phase reference field are constructed, the bubble state is perceived in real time, collapse forebodes are recognized, a dynamic risk fingerprint database is established, directional intervention and reverse energy channel collapse nucleus extinguishing are achieved in combination with an energy aggregation node, finally closed-loop regulation is constructed through calibration write-back, the safety and stability of zinc chloride preparation are improved, and the method is suitable for large-scale popularization and application. And efficient utilization and clean production of solid waste are promoted.
Owner:TIANJIN YOUFA DEZHONG STEEL PIPES CO LTD

Power equipment partial discharge signal denoising method and system

The invention relates to the technical field of signal processing, and discloses a power equipment partial discharge signal denoising method and system, and the method comprises the steps: S1, generating an exponential decay type pulse signal simulating partial discharge, and superposing white noise and narrow-band interference into the exponential decay type pulse signal to generate a noisy signal; s2, decomposing the noisy signal into a plurality of intrinsic mode components through an ensemble empirical mode decomposition method, calculating a correlation coefficient and a kurtosis index of each intrinsic mode component, and identifying a noise component and a signal component based on the correlation coefficient and the kurtosis index; s3, wavelet threshold denoising is carried out on the noise components, and a wavelet threshold is dynamically adjusted for each noise component through a particle swarm optimization algorithm; and S4, reconstructing the de-noised noise component and the reserved signal component into a final de-noised signal, and evaluating the de-noising performance based on the signal-to-noise ratio, the root mean square error, the peak signal-to-noise ratio and the correlation coefficient.
Owner:STATE GRID HUNAN ELECTRIC POWER COMPANY LIMITED +2

Water surface oil stain detection method, system and equipment

The invention belongs to the technical field of oil stain detection, and particularly relates to a water surface oil stain detection method, system and equipment, the water surface oil stain detection system comprises a flexible circuit board FPC, an InGaAs infrared sensor, an infrared narrow-band filter and an optical lens, light enters a visible light camera and the optical lens through an external lens, the visible light camera collects visible light images, and the visible light images are transmitted to the InGaAs infrared sensor; the optical lens focuses a light beam, then light with a specific wavelength is screened out through the near-infrared narrow-band filter, the screened light is received by the InGaAs infrared sensor, and the InGaAs infrared sensor is connected with the FPC; the method has the advantages that visible light imaging and short wave infrared spectrum analysis technologies are ingeniously fused, so that the accuracy and the reliability of oil stain detection are remarkably improved. Under the current background that environmental protection and water resource management are increasingly severe, powerful technical support is undoubtedly provided for water surface pollution monitoring.
Owner:SHANDONG UNIV

Tunable excited Raman spectrum microscopic imaging method and device

The invention discloses a tunable excited Raman spectrum microimaging method and device, and belongs to the field of spectrum detection and optical imaging. The device comprises a broadband adjustable wavelength light source, a high-resolution wavelength scanning module, a stimulated Raman signal excitation module and a stimulated Raman signal detection module. The stimulated Raman signal excitation and imaging module is used for focusing the two beams of narrow-band femtosecond pulse light which are overlapped in time and space on a sample and exciting a stimulated Raman signal, and meanwhile, moving the sample to realize spot scanning microscopic imaging; and the stimulated Raman signal detection module is used for converting the stimulated Raman scattering signal into an electric signal, demodulating the electric signal by using a lock-in amplifier, and recording spectral information by using a data acquisition card. According to the invention, the broadband tunable characteristic of the optical parametric amplifier is utilized to tune the pump light to the wavelength region of the sample absorption peak length so as to realize electron pre-resonance stimulated Raman; and a balance detection technology is combined at a detection end, so that high-sensitivity, high-resolution and high-signal-to-noise-ratio detection of stimulated Raman signals is realized.
Owner:BEIJING INST OF TECH

Acoustic metasurface with aperture switching modularity

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies selected via interchangeable portions. A sound absorbing unit cell is designed and constructed in two parts based on a desired resonance frequency, such as a neck portion and air chamber portion. The portions are dimensioned such that when coupled together, Helmholtz resonators are formed that resonate at a desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A portion with different dimensions can be interchanged to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.
Owner:DELL PROD LP

Cavity target infrared characteristic calculation ray tracing method

The invention provides a cavity target infrared characteristic calculation ray tracing method, and belongs to the technical field of infrared tracing. The method comprises the following steps: importing a CFD data source; a cuboid space grid is generated, and CFD data space distribution is interpolated and reconstructed; a target material and temperature parameters are set; determining the position of a detector and forming a detection situation relationship; gridding a detection space in the transverse direction and the longitudinal direction at the position of the cavity object to form a field pixel space; constructing a reverse ray vector direction, and counting self reflection and reflection radiation of each triangular infinitesimal according to a recursive iteration mode; reconstructing a broadband spectral reflection coefficient according to the narrowband BRDF model and the broadband spectral emissivity; and determining the reflection direction of the infrared rays based on a bidirectional reflection distribution model to realize ray tracing. According to the invention, the control of any ray tracing depth can be realized, the intersection judgment process is greatly simplified, and the problem of high-efficiency and high-precision calculation of the cavity and the low-emission material is effectively solved.
Owner:THE 54TH RESEARCH INSTITUTE OF CHINA ELECTRONICS TECHNOLOGY GROUP CORPORATION

Multi-channel narrowband data link comprehensive processing module

The invention relates to the technical field of communication technologies and navigation systems, and discloses a multi-channel narrowband data link comprehensive processing module, which comprises a radio frequency transceiver module which comprises a radio frequency transceiver and is used for converting a received radio frequency signal into a baseband signal and converting the baseband signal into a radio frequency signal; the analog channelization module is connected with the radio frequency receiving and transmitting module and used for receiving the baseband signals converted by the radio frequency receiving and transmitting module, carrying out preliminary channel division on the signals and dividing the signals into a plurality of frequency band signals; and the digital channelization processing module is connected with the analog channelization module and is used for carrying out digital processing on the signal after analog channelization. By adopting a zero intermediate frequency architecture, a multi-stage channelization design, cooperative work of the FPGA and the SOC, precise clock synchronization and an anti-interference technology, the multi-channel signal processing precision and the system stability are improved, and meanwhile, the power consumption and the hardware complexity are reduced.
Owner:RINENG TECH (BEIJING) CO LTD

Layered ternary selenide, layered ternary selenide single crystal material and preparation method of layered ternary selenide single crystal material

The invention discloses a layered ternary selenide, a layered ternary selenide single crystal material and a preparation method of the layered ternary selenide single crystal material, and belongs to the technical field of crystal materials. The chemical formula of the layered ternary selenide is In2Ge2Se6, indium powder, germanium powder and selenium powder in a specific ratio are adopted as raw materials, synthesis of the layered ternary selenide In2Ge2Se6 single-phase material is achieved through the processes of high-temperature melting, heat preservation in a specific temperature interval and quenching, and the material has a narrow band gap and low heat conductivity and can be used for preparing the high-temperature-resistant layered ternary selenide In2Ge2Se6 single-phase material. And the thin-layer nanosheet single crystal material with the millimeter-level area can be prepared by a mechanical stripping method, and can be applied to the fields of semiconductor photoelectric devices, solar cells, thermoelectric devices and the like.
Owner:JIHUA LAB

Calibration device with spectrum self-calibration function and high-resolution spectrum calibration method thereof

The invention discloses a calibration device with a spectrum self-calibration function and a high-resolution spectrum calibration method thereof. The device comprises a narrow-band light source, a broadband light source, an optical fiber isolator, a coupler, an interference system, a multi-way switch, an FP (Fabry-Perot) cavity, a collimator, an orthogonal dispersion system and a computer, wherein the orthogonal dispersion system consists of a cylindrical lens, a reflector, a virtual phase array, a grating, a focusing lens and an industrial camera; according to the device, different light source paths are gated, FP cavity modulation and orthogonal dispersion system light splitting are utilized, and an industrial camera is combined to receive light signals. According to the method, the mapping relation between pixels and wavelengths can be established, the two-dimensional spectrum is compressed into the one-dimensional calibration spectrum through light intensity modulation and normalization processing, the calibration process of the orthogonal dispersion system is simplified, and the measurement precision is improved; and system drift can be compensated in real time through self-checking calibration, and the reliability of a measurement result is ensured, so that accurate calibration and measurement of a high-resolution spectrum can be realized.
Owner:HEFEI UNIV OF TECH