Abstract: A method for measuring the concentrations of species present at at least one point of a separation unit operating in simulated moving bed (SMB) mode, or a hybrid separation unit employing a step for simulated moving bed (SMB) separation and a step for crystallization, by calibration by inline acquisition of Raman spectra for different mixtures; analysis by inline signal processing of the Raman spectrum.

Abstract: An analysis (e.g., LIBS) system includes a source of radiation, an optical emission path for the radiation from the source of radiation to a sample, and an optical detection path for photons emitted by the sample. A detector fiber bundle transmits photons to the spectrometer subsystem. At least one fiber of the fiber bundle is connected to an illumination source (e.g., an LED) for directing light via at least a portion of the detection path in a reverse direction to the sample for aligning, sample presence detection, localizing, and/or focusing based on analysis of the resulting illumination spot on the sample.

Abstract: A compact optical imaging system including a single filter and a light source that provides lateral illumination for bead detection in digital assays. The light source is configured to emit light toward the detection vessel. The single filter is positioned to receive light reflected from a sample in the detection vessel, that originated from the light source, and receive an output from a sample in the detection vessel. A detector is configured to receive a portion of the reflected light and a portion of the output that passes through the single filter.

Abstract: Assay modules, preferably assay cartridges, are described as are reader apparatuses which may be used to control aspects of module operation. The modules preferably comprise a detection chamber with integrated electrodes that may be used for carrying out electrode induced luminescence measurements. Methods are described for immobilizing assay reagents in a controlled fashion on these electrodes and other surfaces. Assay modules and cartridges are also described that have a detection chamber, preferably having integrated electrodes, and other fluidic components which may include sample chambers, waste chambers, conduits, vents, bubble traps, reagent chambers, dry reagent pill zones and the like. In certain preferred embodiments, these modules are adapted to receive and analyze a sample collected on an applicator stick.

Abstract: A method for detecting and quantifying additives in a complex aqueous fluid, and a method for detecting an inhibitor of mineral deposition or corrosion, injected in a gas or oil well. The invention also relates to a developer solution including a lanthanide and a chelating agent for detecting said additives or inhibitors.

Abstract: A lightguide aggregate inspection device includes a reaction spot array including multiple reaction spot array elements having at least one reaction spot, a light-receiving element array having a light-receiving surface provided with multiple light-receiving regions each having at least one light-receiving element corresponding to each of the reaction spot array elements, and receiving light obtained based on an optical state resulting from reaction in each of the reaction spots, multiple lightguide paths provided to correspond to the reaction spot array elements, and each having a measurement end provided close to or in contact with, or to be movable close to or into contact with 1 reaction spot, and a connection end provided close to or in contact with the light-receiving region, and a digital data conversion unit configured to convert image region data obtained from the light-receiving elements corresponding to the light-receiving regions, into digital data.

Abstract: Nanoreactors comprising a metal precursor in a carrier are provided. In some embodiments, upon exposure to heat, the metal precursor forms nanoparticles that can be detected, e.g., by detecting a color change in the nanoreactor and/or by detecting the number and/or size and/or size distribution and/or shape of the nanoparticles. The nanoreactors can be used, in some embodiments, as time-temperature indicators for perishable goods.

Abstract: Disclosed herein are devices and methods for screening gemstones (e.g., diamonds). In particular, the disclosed method and system can efficiently and accurately identify and distinguish genuine earth-mined gemstones (e.g., diamond) from synthetic and treated gemstones or gemstone simulants.

Abstract: The present disclosure relates to a method for characterizing a light source. The method includes providing a light source to be characterized, collecting light emitted from the light source by using imaging optics, the imaging optics generating a pupil of the collected light emitted from the light source, generating an image of a pupil of light emitted only from a first surface area of the light source at a detector using the imaging optics, laterally shifting the light source and the imaging optics relative to each other and after the lateral shift, generating an image of a pupil of light emitted only from a second surface area of the light source at the detector using the imaging optics. The imaging optics includes a field stop between the light source and the detector to select a portion of the light source's surface from which light is imaged at a time.

Abstract: In a method of inspecting a steel strip, at least one surface of the steel strip is illuminated and scanned by at least one camera so as to generate an image record that defines a two-dimensional image of the scanned surface. The image record is sent to an image processing unit, with the image processing unit subjecting the image record to the detection of defects and, upon detection of a surface defect, classifying the detected surface defect. The steel strip is magnetized and the magnetic flux leakage on the surface of the steel strip is detected by at least one magnetic field-sensitive flux leakage sensor in order to detect inhomogeneities in the interior of the steel strip, with the flux leakage sensor generating a flux leakage record that is sent to the image processing unit and that is subjected by the image processing unit to the detection of defects so as to identify inhomogeneities in the interior of the steel strip.

Abstract: An inspection system having a light source, a mirror sensor, and an image sensor. The mirror assembly is aligned with the camera; the light is reflected from the container to the camera, and the camera creates multiple images of the container at a viewing angle. The multiple images are analyzed to detect defects.

Abstract: Implementations disclose methods and devices for closure control of containers. A method includes performing, by an inspection apparatus, optical 3D measuring of a closed container, the closed container comprising a closure coupled to the container; generating, by the inspection apparatus, 3D data based on the optical 3D measuring; and processing, by an evaluation device, the 3D data to determine at least one of tightness or correct seating of the closure relative to the container.

Abstract: A movable ray inspection system used to be mounted in a container yard to inspect an object within a container is provided. The movable ray inspection system includes: a ray generator device configured to emit a ray, a ray receiving device configured to receive the ray, and at least one chamber for receiving the ray generator device and the ray receiving device therein. Each of the at least one chamber is configured to be a standard container or a chamber which has a same shape, a same size and a same structure as a standard container such that the movable ray inspection system is adapted to be stacked in the container yard.

Abstract: In an embodiment, a system for wear monitoring, includes a wear surface, a metallic reflector embedded in the wear surface, a radio-wave transmitter, and a radio-wave receiver. The metallic reflector reflects radio waves transmitted by the radio-wave transmitter for detection by the radio wave receiver. Attenuation of the radio waves between transmission by the radio-wave transmitter and detection by the radio-wave receiver indicates a degree of wear of the wear surface.

Abstract: Provided are an image acquisition device and an image acquisition method capable of acquiring the internal and external contours of a measured object with a high degree of accuracy.

Abstract: The X-ray phase imaging apparatus is configured to include an image generation unit that generates an X-ray phase-contrast image based on a phase-contrast between a step curve representing an intensity change of an X-ray when an object is placed between an X-ray source and a phase grating or between a phase grating and an absorption grating and a step curve when no object is placed therebetween, and is configured to obtain a displacement amount of relative positions of a plurality of gratings based on a plurality of step curves.

Abstract: The present invention provides a method and a device for measuring a formation elemental capture gamma ray spectrum, pertaining to the field of oil-gas exploration and well logging technologies. The method comprises: performing moderation on neutrons emitted from a neutron source according to a neutron capture cross section of a test sample; and adjusting a relative location of the test sample with respect to the neutron source, so that a standard capture gamma ray spectrum of the test sample is measured and obtained at a location where a thermal neutron flux reacting with atomic nucleuses of the test sample reaches a first predetermined value. The present invention performs moderation on a neutron source according to neutron capture cross sections of different test samples to measure and obtain elemental capture gamma ray spectra of the test samples, thereby obtaining various formation elemental capture gamma ray spectra with higher accuracy.

Abstract: A monitoring system and method are provided for determining at least one property of an integrated circuit (IC) comprising a multi-layer structure formed by at least a layer on top of an underlayer. The monitoring system receives measured data comprising data indicative of optical measurements performed on the IC, data indicative of x-ray photoelectron spectroscopy (XPS) measurements performed on the IC and data indicative of x-ray fluorescence spectroscopy (XRF) measurements performed on the IC. An optical data analyzer module analyzes the data indicative of the optical measurements and generates geometrical data indicative of one or more geometrical parameters of the multi-layer structure formed by at least the layer on top of the underlayer.

Abstract: A Process of determining at least one thermal property of a fluid under investigation with a thermal sensor. The thermal sensor has at least a first sensor element that is heated to provide heat to the fluid under investigation. The first or a second sensor that can sense the temperature of the fluid under investigation, wherein the process is characterized by the following steps: a) Providing a calibrated reduced order model which is calibrated with one or more thermal properties of at least a second and a third fluid; b) (Applying an amount of heat to the fluid under investigation by the first sensor element and) measuring the temperature Tsens at the first and/or second sensor element said fluid under investigation; and c) Extracting one or more thermal property of the fluid under investigation by applying the said temperature Tsens to said calibrated reduced order model.

Abstract: The disclosed technology relates to a method of selecting a material composition and/or designing an alloy. In one aspect, a method of selecting a composition of a material having a target property comprises receiving an input comprising thermodynamic phase data for a plurality of materials. The method additionally includes extracting from the thermodynamic phase data a plurality of thermodynamic quantities corresponding to each of the materials by a computing device. The extracted thermodynamic quantities are predetermined to have correlations to microstructures associated with physical properties of the material. The method additionally includes storing the extracted thermodynamic quantities in a computer-readable medium. The method further includes electronically mining the stored thermodynamic quantities using the computing device to rank at least a subset of the materials based on a comparison of at least a subset of the thermodynamic quantities that are correlated to the target property.

Abstract: Embodiments include a system and circuit for measuring characteristics of a material under test (MUT). In some cases, the system includes a circuit having level detectors to measure the change in strength between a reference signal and a return signal passed through the MUT. The system can include a computing device to evaluate the measured signals and adjust those signals within range of the level detectors and other circuit components. Circuits can include a time-of-flight digital convertor for determining the phase shift between the reference and return signals that pass through the MUT. The measured difference in signal strength and phase can be used to compute the complex impedance or dielectric properties of the MUT. This impedance or dielectric property can be correlated with a physical property of the MUT. The system may be operated at a single frequency, or over a range of frequencies.

Abstract: A number of variations may involve a method that may include providing a non-conductive layer. A conductive layer may be provided overlying the non-conductive layer with the conductive layer to form a sensor device. An opposition to electrical current through the conductive layer may be monitored. The location of a status of the non-conductive layer or of the conductive layer may be determined through a change in the opposition.

Abstract: A determination device for determining an improvement in water quality, capable of determining it in no time, is provided. The device has a first measuring device for measuring by AC terminal electric conductimetry a capacitance of a first capacitor formed between a pair of electrodes immersed in untreated water to be supplied to a water quality-improving apparatus; a second measuring device for measuring by AC terminal electric conductimetry a capacitance of a second capacitor formed between a pair of electrodes immersed in water discharged by the apparatus; and a processor for calculating a ratio (Y/X) of a capacitance Y to a capacitance X wherein the capacitance X is a capacitance of the first capacitor outputted by the first measuring device when an AC frequency is 100 Hz or less, and the capacitance Y is a capacitance of the second capacitor at the same frequency outputted by the second measuring device.

Abstract: The invention relates to measuring devices for determining physical properties, chemical properties, biological properties and/or substances in the environment of at least one transducer or of the at least one transducer itself as a component of the particular measuring device. The measuring devices are in particular characterised in that they are simple and robust to control and their function can be influenced. For this purpose, the measuring device consists of at least one transducer as a component of a passive device and/or as a component of an active measuring functional unit. The active measuring functional unit further consists of a data-processing system and a transceiver unit for electromagnetic radiation, and is interconnected to an electric power source.

Abstract: An auto-calibration system for diagnostic test strips is described for presenting data individually carried on each test strip readable by a diagnostic meter. The test strip meter may provide a predetermined varying resistance on one strip or a plurality of varying resistances from strip lot to strip lot.

Abstract: The present invention relates to the technical field of electrochemical detection, in particularly to a method for distinguishing between quality control liquid and real sample in an electrochemical test system with recognition device controller and recognition system. The method includes: (1) applying an AC voltage signal to the electrode surface(s) of an electrochemical test strip, (2) measuring the AC impedance angle (phase angle) value between working electrode and reference electrode after drawing a test sample into the fluid chamber of an electrochemical test strip, (3) automatically judging the test sample as quality control liquid or real sample according to the AC impedance angle value.

Abstract: A method of verifying operation of a meter for reading electrochemical test devices, includes obtaining a reference output signal indicative of a response generated at an electrochemical test device when the electrochemical test device reacts with a reference test fluid; applying with the meter an algorithm to the reference output signal so as to obtain a reference test result, wherein the algorithm is for use in estimating an unknown concentration of an analyte in a sample of the reference test fluid; and determining whether the reference test result is valid so as to verify operation of the meter.

Abstract: The present disclosure relates to a device in particular, a sensor for determining a measurand correlated with a concentration of an analyte in a measuring medium, including a housing that has a region provided for contacting the measuring medium, a fluid line arranged in the housing, an interface that is arranged within the region provided for contacting the measuring medium and has a first side which is in contact with the fluid line and a second side which is in contact with an environment of the housing in particular, with the measuring medium in contact with the housing, a first reservoir that is arranged in the housing and fluidically connected to the fluid line and which contains a reagent intended for contacting and/or interacting with the analyte, and a transport mechanism that is designed to transport reagent from the first reservoir into the fluid line.

Abstract: A micromachined ion-selective electrode for an ion-selective sensor is provided. The ion-selective electrode includes a reservoir that is arranged to contain electrolyte, a contacting electrode that is arranged at least partially within the reservoir to contact electrolyte in the reservoir, and an ion-selective membrane that is arranged to contact a bulk solution under test. The ion-selective electrode further includes a constriction for providing an ionic connection between the bulk solution and electrolyte in the reservoir via the ion-selective membrane. Also provided is an ion-selective sensor that includes at least one such micromachined ion-selective electrode.

Abstract: An analyte concentration can be measured at an electrochemical detector using a waveform that includes a reductive voltage. The waveform may include three or four different voltages, in which at least one of the voltage values is reductive. One or more current or charge values can be measured during at least part of a reductive voltage portion of the waveform. The analyte concentration can be calculated based on the measured one or more current or charge values.

Abstract: An NOx sensor includes a gas sensor element, a body member made of metal, and a protector made of metal. The body member is formed into a tubular shape extending in an axial direction and accommodates a gas sensor element internally of the same. The NOx sensor is formed into a tubular shape extending in the axial direction and includes an attachment member disposed such that a space extending in the axial direction is formed between the attachment member and the body member. The gas sensor element includes an oxygen concentration detection cell having an oxygen ion-conductive solid electrolyte layer and a detection electrode and a reference electrode formed on the solid electrolyte layer and forming a pair, and a heater for heating the oxygen concentration detection cell to a predetermined temperature. The oxygen concentration detection cell is disposed in the space.

Abstract: A gas sensor device is equipped with a diffusion controlling portion, a pump cell, and a sensor cell. The diffusion controlling portion is formed to face a major surface of a solid electrolyte body and works to control a rate of diffusion of a measurement gas entering a measurement gas chamber. The pump cell has a pump electrode which contains gold and is formed on the major surface. The pump electrode is located downstream of the diffusion controlling portion in a gas flow direction. The pump cell works to regulate a concentration of oxygen in the measurement gas upon application of voltage to the pump electrode. The sensor cell has a sensor electrode formed on the major surface downstream of the diffusion controlling portion in the gas flow direction. The sensor cell works to measure a concentration of nitrogen oxide contained in the measurement gas upon application of voltage to the sensor electrode. The pump electrode is disposed upstream of the sensor electrode at a distance of 0.

Abstract: A gas detection device includes a voltage applying unit configured to apply a voltage across a first electrode and a second electrode of an electrochemical cell and a measurement control unit configured to perform a first application voltage sweep and a second application voltage sweep which have different sweeping voltage ranges, to acquire a first parameter based on the output current of the first application voltage sweep, to acquire a second parameter based on the output current of the second application voltage sweep, to calculate a SOx detection parameter which is a difference or a ratio between the first parameter and the second parameter, and to perform determination of whether sulfur oxides with a predetermined concentration or higher are contained in an exhaust gas or detection of a concentration of sulfur oxides in the exhaust gas based on the SOx detection parameter.

Abstract: A gas sensor element of the present disclosure includes a measurement gas chamber, a pump cell, a sensor cell including a sensor electrode, and a pump-cell controller. When the gas sensor element is activated before detecting a concentration of a gas, in order to remove oxygen occluded in the sensor electrode, the pump-cell controller applies a removing voltage to the pump cell so that a reducing gas is generated. The sensor electrode has a plurality of noble metal regions which are made of noble metal and electrolyte regions which are distributed so that an interface is generated between a part of a solid electrolyte body and the plurality of noble metal regions. The sensor electrode has an open pore which extends from an electrode surface of the sensor electrode and reaches at least one of the plurality of noble metal regions.

Abstract: A gas sensor element of the present disclosure includes a measurement gas chamber, a solid electrolyte body, and a sensor electrode. The sensor electrode has a noble metal region which contains at least Rh and Pt, an electrolyte region which is formed by a solid electrolyte, and a mixed region in which the noble metal and the solid electrolyte are mixed. With respect to a correlation curve which represents a correlation between a mass percentage concentration c of Rh and a thickness d of the mixed region, when a reaction resistance to a measured gas in the sensor electrode is 40 k?, the concentration c of Rh and the thickness d are set so that at coordinates (c, d), the concentration c has a positive coordinate point and the thickness d has a positive coordinate point.

Abstract: A semiconductor device including a biosensor with an on-chip reference electrode embedded within the semiconductor device, and associated manufacturing methods are provided. In some embodiments, a pair of source/drain regions is disposed within a device substrate and separated by a channel region. An isolation layer is disposed over the device substrate. A sensing well is disposed from an upper surface of the isolation layer overlying the channel region. A bio-sensing film is disposed along the upper surface of the isolation layer and extended along sidewall and lower surfaces of the sensing well. A reference electrode is disposed vertically between the bio-sensing film and the isolation layer.

Abstract: An apparatus comprising a channel member(401), first and second electrodes (403, 404) configured to enable a flow of electrical current from the first electrode through the channel member to the second electrode, and a supporting substrate (402) configured to support the channel member and the first and second electrodes, wherein the channel member is separated from the supporting substrate by a nanomembrane (411) configured to facilitate the flow of electrical current through the channel member by inhibiting interactions between the channel member and supporting substrate. Possibly, a conductive shield layer (412) is present between the substrate and the nanomembrane, which may be a nanomembrane as well. The apparatus may also include a gate electrode (406) and a gate dielectric (407), the latter possibly being a nanomembrane as well. The apparatus may be configured to sense analyte species (513) as shown in FIG.

Abstract: An electrophoresis apparatus having a blue light system comprises a tiltable chamber for electrophoresis. The tiltable chamber operates in a horizontal position, a vertical position, and in one or more inclined positions having an angle between the angle of the horizontal position and the angle of the vertical position. The electrophoresis apparatus is usable for separating molecules.

Abstract: The present invention relates to a method for determining size of biomolecules separated in a medium by an electric field using marker molecules of known size, comprising—(101) detecting a plurality of bands and forming a detected marker sequence and a detected unknown sequence based on a separation criterion, —(102) determining band properties for each detected band, —(103) comparing the band properties of the detected bands of the detected marker sequence with known band properties for a plurality of marker molecules forming a known marker sequence and assigning a score to each comparison, said score being based on at least one of relative distance, relative intensity, expected distance and expected intensity between bands, —(104) selecting the comparison with the highest score and associating all or a subset of the detected bands of the detected marker sequence with said plurality of marker molecules of the known marker sequence in accordance with said comparison to determine size of the all or a subset of

Abstract: A microfluidic ion detector for detecting heavy metal ions in liquid and particulate matter from gas samples is described. The microfluidic ion detector includes a sample extraction structure for extracting sample ions from a sample liquid or extracting sample ions from the particulate matter of a gas sample, a separation structure for separating sample ions of different types once extracted, and a detection structure for detecting the sample ions. The microfluidic ion detector also includes a reference reservoir providing a reference ion against which the sample may be calibrated based on the operation of the separation structure. A portable, self-calibrating ion detector may be realized by including the described components on a single substrate.

Abstract: Translocation events are sensed using composite nanopore assemblies including nanopores formed in graphene sheets. Single molecule detection and characterization and multi-molecule characterization and identification are provided using such assemblies. Multiple electrodes associated with nanofluidic sensors facilitate detection of ionic current through a nanopore as well as tunneling currents. Current signals of individual molecules are estimated from the combination of an ionic current signal through the nanopore and tunneling current signals obtained at specific locations within the nanopore.

Abstract: A gas detection device includes: an element portion; a voltage applying unit configured to apply a voltage across a first electrode and a second electrode on surfaces of a solid electrolyte; a current detecting unit configured to detect an output current flowing between the first electrode and the second electrode; and a measurement control unit. The measurement control unit acquires a parameter which has a correlation with a degree of change of the output current increasing as a concentration of sulfur oxides in an exhaust gas increases based on the output current, and performs determination of whether the concentration of sulfur oxides in the exhaust gas is equal to or higher than a predetermined value or detection of the concentration of sulfur oxides in the exhaust gas based on the acquired parameter.

Abstract: Methods of characterizing ion-exchanged chemically strengthened glass containing lithium are disclosed. The methods allow for performing quality control of the stress profile in chemically strengthened Li-containing glasses having a surface stress spike produced in a potassium-containing salt, especially in a salt having both potassium and sodium. The method allows the measurement of the surface compression and the depth of the spike, and its contribution to the center tension, as well as the compression at the bottom of the spike, and the total center tension and calculation of the stress at the knee where the spike and the deep region of the stress profile intersect. The measurements are for a commercially important profile that is near-parabolic in shape in most of the interior of the substrate apart from the spike.

Abstract: The present disclosure is directed to methods and devices for moisture-based calibration. In particular, the present disclosure is directed to moisture monitoring devices that trigger calibration of substance detection devices.

Abstract: A system for monitoring machine fluids is provided. The system includes a fluid handling unit configured to pump the fluid and the fluid handling unit includes at least one fluid handling element. A magnetic material on the at least one fluid handling element is configured to generate a magnetic field. A sensing element located within the magnetic field is configured to measure fluctuations in the magnetic field.

Abstract: A magnetic particle inspection tool is provided including a yoke with an inspection magnet, a first magnetic member, and a second magnetic member. The inspection magnet is configured to magnetize a work piece. The first magnetic member is rotatable relative to the inspection magnet between a first position and a second position, and the inspection magnet is slidable relative to the first magnetic member. The first magnetic member and second magnetic member include a plurality of magnetic sources forming a magnetic surface with a first magnetic pattern and a magnetic surface with a second magnetic pattern. The magnetic surfaces are magnetically attracted when the first magnetic member is in the first position and repelled when in the second position.

Abstract: A pipe pig for travelling along the bore of a pipe, the pipe pig comprising a body formed of a deformable material comprising foam, and a plurality of electromagnetic sensors disposed about an outer surface of the body or within the body. The plurality of electromagnetic sensors include means for inducing an electric current in a wall of the pipe, and means for receiving an electromagnetic signal from the wall of the pipe, such that data about the pipe wall can be obtained as the pipe pig travels along a bore of the pipe.

Abstract: The present invention addresses the problem of checking defects of a rail for a vehicle with a high SN ratio. A detection device (2) for generating check data related to the defects of a railway rail RR (rail for a vehicle) is provided with an oscillating coil C1 (211) and an oscillating coil C2 (211) that are disposed on the surface opposite the railway rail RR and generate AC magnetic fields whose directions are opposite to each other, and a receiving coil (212) that is positioned between or in the vicinity the oscillation coils and that outputs a magnetic field waveform based on the magnetic fields received from the oscillating coils as the check data.

Abstract: The invention concerns a Thickness Shear Mode (TSM) biosensor (1) which comprises an ex vivo living skin explant (2), the skin explant (2) comprising at least one of the skin layers among: hypodermis, dermis (2A), epidermis (2B) and the stratum corneum (2C), a TSM transducer (3) which comprises: an AT cut quartz resonator 3C which has two opposite exterior surfaces (3A,3B), and two conducting electrodes (4A, 4B), each conducting electrode being deposited on one of the two exterior surfaces (3A,3B), the TSM transducer (3) allowing to determine micro rheological characteristics of the living skin explant (2) by piezoelectric transducing using shear waves, the TSM transducer (3) presenting: measuring means (30), monitoring and calculating means (31) which monitor an evolution in time of an electrical response of the living skin explant (2), and which calculate in time, from the electrical response, micro rheological characteristics of the living skin explant (2), a bottom surface of the skin explant (2) being in

Abstract: A method for detecting a defect of a metal plate includes selecting N controllable emitting electromagnetic acoustic transducers EMATs as excitation transducers, and selecting M omnidirectionally receiving EMATs as receiving transducers, exciting an ultrasonic guided wave in a metal plate by a nth controllable emitting EMAT with a predetermined emission angle; determining whether each of M1 omnidirectionally receiving EMATs and the nth controllable emitting EMAT form a scattering group; for the scattering group, solving a position of a scattering point and a direction of a scattering side according to a distance between Tn and Rm1, the emission angle and a travel time of the ultrasonic guided wave; performing a curve fitting on all the scattering points in directions of respective scattering sides to obtain a contour image of the defect.