142 results about "Spectral width" patented technology

A system, apparatus and method directed to detecting damage to an optical fiber of a medical device. The optical fiber includes one or more core fibers each including a plurality of sensors configured to (i) reflect a light signal based on received incident light, and (ii) alter the reflected light signal for use in determining a physical state of the multi-core optical fiber. The system also includes a console having non-transitory computer-readable medium storing logic that, when executed, causes operations of providing a broadband incident light signal to the multi-core optical fiber, receiving reflected light signals, receiving reflected light signals of different spectral widths of the broadband incident light by one or more of the plurality of sensors, identifying at least one unexpected spectral width or a lack of an expected spectral width, and determining the damage has occurred to the optical fiber based on the identification.

The invention relates to the field of meteorological detection and analysis, and discloses a low-altitude complex wind field detection and inversion method based on a vehicle-mounted laser radar, and the method comprises the steps: determining a scanning point location based on the terrain, building distribution and simulation data; optimizing the driving path of the vehicle-mounted radar to cover the high-risk area; acquiring three-dimensional wind field data by adopting an RHI and PPI multi-mode scanning strategy; the influence of vehicle-mounted movement on speed measurement is corrected; calculating turbulence intensity and vortex nucleus position by using spectral width characteristics; and identifying the wind shear position and strength through a slope algorithm. According to the invention, low-cost and high-precision wind field detection is realized through maneuvering deployment and multi-mode cooperation, and reliable technical support is provided for safe flight of the unmanned aerial vehicle, low-altitude traffic management and meteorological early warning.

A medical device system includes a stylet with an optical fiber and a console operatively coupled to the stylet. The optical fiber can include an electrically conductive concentric tube configured to transmit electrical signals and a plurality of core fibers within the concentric tube. Each of the plurality of core fibers can include a plurality of sensors, and each the plurality of sensors can be configured to reflect a light signal of a different spectral width based on received incident light and change a characteristic of the reflected light signal based on a condition experienced by the stylet. The console includes one or more processors and a non-transitory computer-readable medium with logic that causes operations including providing an incident light signal to the optical fiber and receiving reflected light signals of different spectral widths of the received incident light by the plurality of sensors.

The invention discloses a composite precipitation cloud layer identification method based on a laser radar-cloud radar, and the method comprises the steps: obtaining the observation data of the laser radar and the cloud radar, and carrying out the data matching of the observation data; processing a signal of the laser radar in a height interval of 18-20 km to obtain a preprocessed laser radar signal; performing laser radar cloud boundary identification based on a VED algorithm, and endowing different laser radar cloud scores according to the signal attenuation rate and the signal gradient; removing earth surface clutters by using a threshold method based on observation of spectral width and Doppler velocity; carrying out cloud radar significant echo recognition based on a threshold method, and determining the cloud score of the cloud radar according to different reflectivity factor signal intensities; determining a light rain area and a heavy rain area according to the Doppler velocity; cloud layer boundary information and a hairy rain area are obtained through cloud layer recognition result fusion, and cloud layer recognition and rainfall area recognition are completed; according to the invention, the accuracy of weather prediction is improved.

The invention discloses a weather radar data quality control method based on a dynamic clutter map and texture features, and relates to the technical field of weather radars, and the method comprises the following steps: inputting radar body scanning data; clutter frequency statistics is carried out; generating a mask matrix based on the clutter map and a reflection threshold, preliminarily determining clutter positions based on the mask matrix, and preliminarily filtering clutters; defining 9 * 9 window sliding capture scanning elevation angle data, extracting speed features and spectral width texture features of each layer of scanning elevation angle clutter region, and calculating a speed standard deviation and a spectral width texture standard deviation; performing secondary judgment on the preliminarily filtered clutters by combining the speed standard deviation and the spectral width texture standard deviation, filtering echoes which are secondarily judged to be clutters, and retaining other echoes which are not secondarily judged to be clutters; filling the holes; and outputting the processed radar data. According to the invention, the accuracy and reliability of weather radar data are improved, so that higher-quality data support is provided for meteorological monitoring and forecasting.

The invention relates to the technical field of satellite navigation and ionosphere detection, in particular to a low-latitude ionosphere disturbance and non-uniform body multi-means collaborative detection and classification method. A multi-network cooperation-multi-source fusion observation mode is adopted, full space-time coverage of low-latitude ionosphere disturbance is achieved, in addition, a data fusion method based on physical constraints is applied, an ionosphere-middle atmosphere-troposphere multi-physics field coupling constraint mechanism is constructed, space-time consistency of data obtained through different observation means is optimized, and the low-latitude ionosphere disturbance is obtained. And finally, key characteristic parameters are extracted by using a multi-scale signal processing method, a disturbance characteristic matrix is constructed in combination with radar observation data (such as drift speed and spectral width), a'three-axis nine-element 'disturbance / non-uniform body classification standard is proposed firstly, then deep learning classification is used, accurate classification of low-latitude ionosphere disturbance is realized, and GNSS signal anomaly recognition capability is improved.

The invention provides a wind profile radar spectrum peak estimation method based on a three-parameter dynamic cost function, and the method comprises the steps: 1, carrying out the preprocessing of distance and Doppler spectrum data, and carrying out the three-point moving average smoothing; step 2, noise level estimation based on statistics is carried out; step 3, carrying out candidate spectrum peak selection based on space Doppler window smoothing; 4, performing dynamic weight calculation based on covariance matrix eigenvalue decomposition; step 5, constructing a three-parameter cost function of a distance spectrum peak value RSP power item, a continuity item and a spectrum width consistency item, and performing optimization; and step 6, outputting the optimal spectrum peak trajectory to form a complete wind speed profile trajectory. According to the method, the spectrum peak identification precision and stability in a complex environment can be improved, and the u and v wind correlation coefficients of the estimation method are verified to reach 0.880 and 0.879 through a data set disclosed by an atmospheric radiation measurement website.

The invention relates to a double-light-path broadband multispectral optical imaging system, which is characterized in that broadband multispectral illumination and imaging are separated into a visible light band imaging light path and a near-infrared band imaging light path, so that the spectral width of the visible light band imaging light path and the spectral width of the near-infrared band imaging light path are reduced; the difficulty in correcting chromatic aberration in a broadband multispectral optical imaging system is reduced, and high-quality fundus multispectral images and color images are obtained; meanwhile, a polarization reflection elimination technology is adopted, a visible light wave band image and a near-infrared wave band multispectral image can be obtained at the same time only through the wave bands of visible light and near-infrared light, the elimination difficulty of stray light is reduced, and the accuracy of stray light elimination is improved. According to the design scheme of the visible light band imaging light path and the near-infrared band imaging light path, the coating range of the lens and the polarized light eliminating and reflecting device in the two light paths is narrower, the design is simplified, and the performance is better.

The invention discloses a weather radar meteorological echo and non-meteorological echo identification system, and belongs to the technical field of meteorological radar signal processing. The method comprises the following steps: acquiring radar original data containing reflectivity factors, radial velocity and spectral width, and generating a three-dimensional feature matrix through format standardization, combined noise removal, neighborhood interpolation filling and parameter normalization; constructing a sample set through professional labeling, consistency verification and multi-dimensional data enhancement; a deep convolutional neural network containing a ResNet50 feature extraction module, a CBAM double attention module and a classification output module is constructed, and a binary cross entropy loss function, an Adam optimizer and an early stop regularization strategy are adopted for training optimization; to-be-recognized data is preprocessed and then input into the model, and a classification result and confidence are output. The method does not need manual feature design, significantly improves the recognition stability of echoes difficult to distinguish in a complex scene, adapts to different radars and regional environments, and meets the real-time processing requirements.

The invention provides a sea wave spectrum prediction method based on deep learning, and belongs to the technical field of sea wave spectrum prediction, and the method comprises the steps: calculating an accumulated energy function and relative accumulated energy based on sea wave spectrum data, and fixedly dividing a frequency domain into a plurality of subintervals according to a preset energy percentile threshold value; for each sub-interval, extracting at least one physical feature of segment energy, center frequency, peak frequency and spectral width of the interval, and combining the original spectral vector of the interval with the extracted physical features to form an input feature vector of the sub-interval; an independent neural network model is constructed and trained for each subinterval, the input feature vector of the corresponding subinterval is used as input, and the predicted spectrum vector of the subinterval is output; and splicing the prediction spectrum vectors output by the neural network of each subinterval according to a frequency sequence, performing weighted average processing at the junction of the subintervals, and performing reconstruction to obtain a complete sea wave spectrum prediction result.

The invention discloses a polarization-adjustable antiferromagnetic terahertz source based on a MnPt heterojunction. The polarization-adjustable antiferromagnetic terahertz source comprises a MnPt antiferromagnetic thin film layer, a light metal layer and an anti-oxidation layer, according to the invention, the femtosecond laser is used for exciting the femtosecond laser to generate the terahertz wave, the polarization direction of the generated terahertz wave is changed along with the change of the polarization direction of the femtosecond laser, that is, the polarization direction of the laser is changed by 1 degree, the polarization direction of the terahertz is changed by 2 degrees, the change of the azimuth angle of a sample is not needed, and the width of the generated terahertz spectrum exceeds 5 THz. No extra heavy metal layer needs to be added, the size is miniature, and the thickness is smaller than 40 nm. By adjusting polarization and phase difference of femtosecond laser, adjustability of a linear polarization state, an elliptical polarization state or a circular polarization state can be achieved, the structure is simple, a needed light path is simple, assistance of an external magnetic field or current is not needed, micromachining is not needed, the ultra-high external magnetic field interference resistance is achieved, the cost is reduced, and the application range is wide. And integration of the terahertz source is also facilitated.

An optical fiber characteristic measurement device (1) includes a light detector (16) configured to detect Brillouin scattered light (LS) obtained by causing light to be incident on an optical fiber (FUT); a signal processor (18b) configured to obtain, on the basis of a detection signal (S1) which is output from the light detector, a first Brillouin gain spectrum (B1) which is a spectrum of the Brillouin scattered light obtained in a case where a spectral width of the light incident on the optical fiber is a first width and a second Brillouin gain spectrum (B2) which is a spectrum of the Brillouin scattered light obtained in a case where the spectral width of the light incident on the optical fiber is a second width larger than the first width; and a measurer (18c) configured to measure characteristics of the optical fiber on the basis of the first Brillouin gain spectrum and the second Brillouin gain spectrum.

The invention discloses a defective rock mass early warning method based on a multi-fractal spectrum and a damage variable, and belongs to the technical field of rock mass disaster early warning, and the method comprises the steps: extracting a slope rock mass acoustic emission signal time-varying data sequence, and calculating a dynamic self-adaptive sliding window length; according to the time-varying data sequence, a ringing counting time sequence of each sliding window is determined, multi-scale deconstruction is carried out based on Haar wavelets, and multi-resolution measurement of each subinterval in the sliding window is calculated; determining the upper and lower limits of the weight of each multi-resolution measure, and calculating the spectral width of the multi-fractal spectrum of each sliding window; calculating the rock mass damage index and the damage index acceleration of the rock mass damage index at each moment in the rock mass damage process, and establishing a relation curve between the spectral width of the multi-fractal spectrum and the damage index; and determining a jump point of the damage index acceleration and a jump point of the spectral width of the multi-fractal spectrum according to the relation curve, and when the two jump points occur at the same moment, determining that the moment is a slope damage early warning point.

The present application relates to the technical field of weather radars, and discloses a fully automatic calibration method for a weather radar. In the method, multiple sets of calibration differential signals are injected into a receiver of a weather radar to be calibrated, wherein at least two sets of calibration differential signals differ in injection power, at least two sets of calibration differential signals differ in frequency offset, and at least two sets of calibration differential signals differ in spectral width; then, by combining the injection power, frequency offset, and spectral width of each set of calibration differential signals and measured values of intensity, velocity, and spectral width under the corresponding calibration differential signals, the unified calibration of the intensity, velocity, spectral width, differential reflectivity factor, and differential propagation phase shift can be accomplished. The method innovatively unifies various radar parameters into a single calibration process while ensuring comprehensive calibration of those radar parameters, thereby greatly reducing calibration time and items, optimizing the calibration process, and improving the calibration efficiency.

The present invention proposes a multimode laser frequency comb device and a degenerate multimode control method. The device includes a diamond crystal, an optical frequency degeneration module, and a degeneracy control module. Based on the multimode laser frequency comb device, the present invention applies stress to the diamond crystal according to the degenerate multimode control method, regulating the lattice constant of the diamond crystal, thereby regulating the degeneracy of Raman vibrations and controlling the optical frequency degeneration mode. This converts an existing single-mode laser comb into a multimode laser comb output. This can generate a multimode optical frequency comb consisting of a single mode or multiple single-mode frequency combs with spectral width spacing. This multimode optical frequency comb has the advantages of wide wavelength coverage, large spectral spacing, and multiple spectral width spacings that are tunable.

This invention discloses a design method for a plane-multiplying relay structure of a wide-spectrum, wide-swath hyperspectral imaging telescope, relating to the field of optical design technology. The method includes establishing a model for realizing a controllable aberration-multiplying relay structure. This model consists of four closely related parts: field segmentation, plane multiplication, telecentricity adjustment, and field curvature / distortion adjustment. Based on this model, the interrelationships between the number of field segmentations, plane multiplication rate, image-side telecentricity adjustment, field curvature / distortion adjustment, and relay structure parameters of the hyperspectral imaging system are clarified. Based on these parameter relationships, a design method for the initial relay structure is further proposed. Using the plane-multiplying relay structure of this invention, wide-spectrum, wide-swath hyperspectral imaging is achieved, breaking through the technical bottleneck of traditional telescopes' difficulty in connecting multiple large-field-of-view spectrometers and large-scale detectors.

The application provides a differential-based white light lensless single-frame weakly conjugate reconstruction method, which can realize weakly conjugate image reduction and improve single-frame imaging resolution in a white light lensless imaging system without using additional elements and complex algorithms. The method comprises the following steps: step one, obtaining spectral distribution information of a system light source by using a spectrometer and performing differential processing to obtain a reconstruction wavelength; step two, performing preprocessing on a collected single-frame image by using a hologram average value reduction method; step three, generating light intensity diagrams of different defocusing surfaces by using an angular spectrum propagation formula, and determining a defocusing distance range based on a definition discrimination factor; and step four, calculating differential distribution on different focal planes in the distance range obtained in step three based on numerical differentiation, and obtaining a final result by selection. The application can reduce the requirement of spectral width of a traditional lensless microscope, effectively reduce the cost of the system, improve the imaging resolution of the white light lensless microscope, and reduce the weakly conjugate image in the case of single-frame image collection.

A medical device that functions as a stylet is described. The medical device can include an insulating layer (or jacket) that encapsulates both a multicore optical fiber and a conductive medium. The optical fiber can include a cladding and a plurality of core fibers spatially arranged within the cladding. Each of the core fibers can include a plurality of sensors distributed along a longitudinal length of the corresponding core fiber, and each of the sensors can be configured to: (i) reflect light signals having different spectral widths based on received incident light, and (ii) alter a characteristic of the reflected light signals for determining a physical state of the multicore optical fiber. The conductive medium can provide a path for electrical signals detected at a distal portion of the conductive medium. The conductive medium can be concentric with the cladding, but can be separate from and adjusted to the cladding.

The application provides an airborne dual-band weather radar detection method, which comprises the following steps: S1: adopting a dual-band common-aperture antenna to time-divisionally emit X-band electromagnetic waves and Ka-band electromagnetic waves; S2: a weather radar receives the X-band electromagnetic waves and the Ka-band electromagnetic waves and performs ground clutter suppression; S3: calculating reflectivity Rrf x according to the X-band electromagnetic waves; S4: calculating reflectivity Rrf ka , velocity V ka and spectral width W ka ; S5: performing analysis on weather targets and displaying analysis results. The detection method realizes cloud detection by using the Ka band on the basis of meeting original X-band weather rainfall detection functions, realizes dangerous weather identification and dangerous area warning by comprehensively considering the spatial structure of the cloud and Doppler information, marks weather seriously threatening flight safety in a display picture, and reminds pilots to pay attention. The detection method comprehensively improves the detection perception and display capability of the airborne weather radar on various weathers, further improves flight safety, and reduces unnecessary deviation.

An ultrasound system is disclosed that includes an ultrasound imaging device including a display screen, a processor and memory having stored thereon logic, and an ultrasound probe. The logic of the ultrasound imaging device, upon execution by the processor, can causes an alteration of content displayed on the display screen in accordance of with ultrasound probe movement-related data. The ultrasound imaging device can include a light source configured to provide incident light to the optical fiber cable, the optical fiber cable including a plurality of reflective gratings disposed along a length thereof. Each of the plurality of reflective gratings can be configured to reflect light with different specific spectral widths to provide distributed measurements in accordance with strain applied to the optical fiber cable. The ultrasound imaging device can obtain the ultrasound probe movement-related data through an optical fiber.

This invention relates to a dual-comb control system for a terahertz quantum cascade laser, comprising a first terahertz quantum cascade laser, a second terahertz quantum cascade laser, a first T-type biaser, and a second T-type biaser. The first terahertz quantum cascade laser operates in optical frequency comb mode, while the second terahertz quantum cascade laser operates above a threshold current. The first and second terahertz quantum cascade lasers emit terahertz light from each other. The first terahertz quantum cascade laser also functions as a detector to detect a mixing signal. The state of the mixing signal is switched by changing the power of the radio frequency signal generated by the radio frequency source. This invention enables the switching of the mixing signal between chaotic, unstable, and dual-comb states under high drive current, significantly improving the spectral width and application scenarios of the dual-comb system based on the quantum cascade laser.

This invention discloses a laser beam identification device and method for identifying whether a test beam is a first laser beam or a second laser beam, wherein the spectral widths of the first and second laser beams are different. The laser beam identification device includes a beam expander, an aperture, and a detector. The beam expander allows the output beam formed after the test beam passes through to be incident on a first and a second slit in the aperture. The output light from the first and second slits interferes. The detector is located on the light-emitting side of the aperture and is used to detect the light intensity at at least two positions, which are different positions along the direction of the interference fringes. Based on the light intensity at these at least two positions, the detector determines whether the light field distribution at these positions is a fringe distribution or a uniform field distribution, thereby determining whether the test beam is the first or the second laser beam. This invention has low cost, relatively small size, and low power consumption.

The present application discloses a multi-wavelength label signal processing method, a processor, and a storage medium. The method comprises: acquiring a service spectrum width of an optical service (S110); determining a carrier frequency according to the service spectrum width and a preset carrier frequency range (S120); performing modulation processing on wavelength information of the optical service according to the carrier frequency to obtain a single-frequency label signal or a dual-frequency label signal (S130); and sending the single-frequency label signal or the dual-frequency label signal to a signal receiving end, so that the signal receiving end obtains optical power and the wavelength information according to the single-frequency label signal or the dual-frequency label signal (S140).

The application discloses a kind of short-term wave height distribution characterization methods based on spectral width, it is related to marine engineering technical field, and the method comprises: based on the statistical parameter of given measured short-term sea state calculation spectral width factor;Wherein, statistical parameter includes spectral frequency, spectral peak frequency, energy density spectrum and energy density spectrum maximum;According to local measured data situation determines characteristic parameter;Wherein, local measured data includes the significant wave height under multiple groups of short-term sea state, three-one wave height, spectral frequency, spectral peak frequency, energy density spectrum and energy density spectrum maximum;Distribution parameter is calculated according to characteristic parameter;Based on spectral width factor and distribution parameter determine the exceeding probability of short-term wave height distribution, provide more accurate input parameter for the design and construction of related structure of nearshore engineering, ocean engineering, near island reef engineering, make preparation for the characterization of short-term wave height distribution and short-term wave height prediction.

The invention provides an optical parametric oscillator. The optical parametric oscillator comprises a light beam emitting device and an optical parametric oscillation device. The optical parametric oscillation device comprises an oscillation cavity, a first nonlinear crystal and a second nonlinear crystal, wherein the first nonlinear crystal is arranged in the oscillation cavity and meets I-type phase matching, the second nonlinear crystal is arranged in the oscillation cavity and meets II-type phase matching, and the length ratio of the first nonlinear crystal to the second nonlinear crystal in the optical axis direction ranges from 1: 9 to 9: 1. When the optical parametric oscillation device works, fundamental frequency pump light emitted by the light beam emitting device enters the oscillation cavity, two beams of parametric light are generated under the action of the first nonlinear crystal and the second nonlinear crystal, the parametric light is resonated through the optical parametric oscillation device, and finally the required parametric light is output. Wherein the spectral line widths of the parametric light with the same wavelength generated by the first nonlinear crystal and the second nonlinear crystal are different, the first nonlinear crystal and the second nonlinear crystal are simultaneously placed in the oscillation cavity along the optical axis direction, and the output of the parametric light with different spectral line widths is realized by adjusting the length proportion of the two nonlinear crystals.

Disclosed herein is a system that includes an ultrasound imaging probe having a first optical fiber integrated therein and a console optically coupled with the ultrasound imaging probe via a first elongate member. The console includes one or more processors and a non-transitory computer-readable medium having stored thereon logic, that when executed by the one or more processors, causes operations that can include providing an incident light signal to the first optical fiber via the first elongate member, receiving reflected light signals of different spectral widths of the incident light from the first optical fiber and the second optical fiber, processing the reflected light signals to determine a first three-dimensional (3D) shape extending along a length including at least portions of the first optical fiber and the second optical fiber, and causing rendering of an image of the first 3D shape on a display of the medical system.

The invention relates to the technical field of biological detection, and provides a biological tissue component detection device and a detection method. The biological tissue component detection device comprises a laser unit, a sample table, a polarization unit, a detector, a first scanner and a processor, the polarization unit is used for reflecting the S polarized light emitted by the laser unit to the biological tissue and filtering out the S polarized light in the mixed light reflected by the biological tissue; the detector is used for collecting light intensity of theta polarized light; the first scanner is used for acquiring space coordinates of each region of the biological tissue; and the processor is used for generating a polarization angle spectrum of the single region based on the light intensity and the polarization angle, generating a global polarization angle spectrum of the biological tissue based on the plurality of polarization angle spectrums and the plurality of space coordinates, and detecting the biological tissue based on a peak polarization angle, a spectrum width and a polarization extinction ratio of the global polarization angle spectrum. According to the biological tissue component detection device, spectrum similar substances in multiple industries can be distinguished, and the biological tissue distinguishing accuracy is improved.

The invention belongs to the technical field of lasers. The invention provides an all-fiber laser with adjustable pulse width and a pulse width tuning method. The all-fiber laser comprises a narrow-band dissipation soliton mode-locked fiber laser seed source, a first fiber isolator, a fiber amplifier, a second fiber isolator, an optical circulator and a dispersion element which are sequentially arranged along a light path. The seed source generates a mode-locked pulse with a fixed initial spectral width; the nonlinear effect intensity is controlled by adjusting the driving current of the pumping source, so that the spectrum broadening amount of the pulse in the amplification process is regulated and controlled, the variable total spectrum width is formed, the spectrum width is subjected to linear time-frequency mapping through a dispersion element with a fixed group delay dispersion value, and finally continuous and electric control adjustment of the output pulse width is achieved. The whole system adopts an all-fiber structure, has the advantages of high stability, compact structure, good tuning linearity and the like, and is suitable for industrial processing, sensing and scientific research application scenes needing flexible pulse width regulation and control.

The utility model discloses a wavelength tunable 2 [mu] m single longitudinal mode all-solid-state pulse laser, which belongs to the technical field of lasers, and comprises a pumping source, the output end of the pumping source is provided with a 1: 2 optical coupling system, the output end of the 1: 2 optical coupling system is provided with an input mirror, the output end of the input mirror is provided with a Tm: YAP crystal, and the Tm: YAP crystal is used for generating 2 [mu] m laser; the output end of the Tm: YAP crystal is provided with an acousto-optic modulator, the output end of the acousto-optic modulator is provided with an etalon, the output end of the etalon is provided with a birefringence filter, and the output end of the birefringence filter is provided with an output mirror. The wavelength tunable 2 [mu] m single longitudinal mode all-solid-state pulse laser is simple in structure, can stably generate 2 [mu] m laser, provides a wider wavelength tuning range and more direct tuning, and realizes narrower spectral width at the same time.

The invention discloses a weighted trapezoidal integral white light interference signal peak searching method, which comprises the following steps of: acquiring a group of three-dimensional light intensity data through a white light interference measuring instrument, determining a self-adaptive integral parameter according to the central wavelength and the spectral width of a light source, selecting an integral weighting function, creating an integral window, and then carrying out weighted trapezoidal integral to obtain a white light interference signal peak searching result. And calculating a zero optical path position of the position, traversing each pixel position one by one, and calculating positions of all interference peak values to realize surface topography reconstruction. According to the method, the interference signal peak searching problem in white light interference measurement is solved, and the provided method has high anti-noise capability, high peak searching accuracy and high calculation speed, can be applied to different white light interference measurement instruments, and is wide in application range.