168results about How to "High monitoring sensitivity" patented technology

The invention discloses a vehicle flowrate and vehicle type identification system, which comprises one or a group of magnetic sensor for detecting the interference signal of vehicle to earth magnetic field in static state or in motion, a signal amplification unit, a filtering unit for filtering the amplified signal, a collection unit for converting the analog signal into digital signal, a signal processing unit for classified identification of digital signal according to vehicle type and automatic detection of vehicle flowrate and a display unit for displays the identification result. After experiment, it is proved that the invention is able to accurately identify different vehicle characteristics, precisely work out the identification result of vehicle type and vehicle flowrate, prevent the interference of climate and weather and ensure high identification rate.

The invention provides an automatic inspection type layered settlement instrument. A conduit connection ring is arranged out of a conduit joint, and a conduit sealing head is mounted at the bottom end of a conduit; a settlement ring is arranged out of the conduit, a magnet ring is mounted in the settlement ring, and folding and unfolding anchoring iron sheets are installed out of the settlement ring; the upper end of the conduit is provided with a measuring box, a magnetic induction measuring probe is mounted in the conduit and is connected with a fine cable, the upper end of the fine cable is connected with an electric settlement amount measuring apparatus which is connected with a measurement and control and wireless transmission apparatus, and the measurement and control and wireless transmission apparatus is connected with a radio transmit-receive antenna and further connected with a hand-held monitoring apparatus located out of the measuring box through a signal cable. The automatic inspection type layered settlement instrument is used for long-term monitoring of layered settlement of a soft soil foundation on the land and has the advantages of easy and convenient installation, low cost, high monitoring precision and sensitivity and capacity of automatically monitoring settlement amount of each soil layer to be measured; automatic unmanned monitoring and data acquisition are realized because of automatic wireless transmission of monitoring data to a remote receiver, and the hand-held monitoring apparatus can also be used on site for reception of the monitoring data and real time detection.

The invention relates to an oil production well productivity tracking and evaluating method. The method comprises the following steps of 1) during a fracture construction process, adding liquid indicator agent into a blending truck when preparing prepad fluid and carrying fluid; 2) during the fracture fluid recovery process, performing continuous tracking, monitoring, sampling and measuring; 3) during a pumping overlayer production process, performing sampling at the mouth of a well or a measuring station, obtaining the amount of tracked pumped fluid during normal operation, wherein sampling includes different requirements on different wells; 4) respectively measuring the concentration of liquid indicator agent and the illumination intensity of every preprocessed sample through analyzing instruments to calculate out contribution rate, recovery rate, recovery amount and the like. According to the oil production well productivity tracking and evaluating method, by means of classification, analysis, processing and study of the liquid indicator agent, relevant information such as production liquid component status, productivity (contribution rate), fracture effects and the like.

The invention discloses a vehicle operation monitoring, parameter measuring and calculating, overload monitoring method and system. The vehicle operation monitoring, parameter measuring and calculating, overload monitoring method is a monitoring method when a vehicle is controlled to operate by using a power device; and the power device is a motor. The vehicle operation monitoring, parameter measuring and calculating, overload monitoring method is characterized by comprising the following steps of obtaining a combined calculation value of measuring and calculating objects of the vehicle; judging whether the power transmission status of the vehicle is abnormal or not according to the obtained combined calculation value and a reference value of the measuring and calculating objects, wherein the measuring and calculating object is any one or more of vehicle mass, a source power parameter and a system operation parameter of the vehicle; and the combined calculation value is figured out with vehicle motion balance as principle; and the source power parameters comprise any one or both of a motor driving parameter and rear-end electric power parameter; and if the judging result is that the power transmission status of the vehicle is abnormal, starting a set power transmission abnormality processing mechanism.

The invention provides a method and a system for monitoring deformation of a two-dimensional surface based on microwave interference. The method for monitoring the deformation comprises the followingsteps of S1, selecting stable reference points and target to-be-monitored points; S2, solving the deformation amount of each point; S3, compensating the error; S4, solving the horizontal displacementand vertical displacement; S5, monitoring the deformation. The system for monitoring the deformation comprises at least two microwave interference deformation measuring radars, n stable reference points, a plurality of target to-be-monitored points, a radar control system and a remote monitoring platform, wherein n is greater than or equal to 2; the radar control system comprises an error compensation module, a displacement calculation module and a deformation monitoring module. The system has the advantages that the system is suitable for monitoring the deformation of edge slops and dams; theinstallation is simple and convenient, the use cost is low, the automation degree and accuracy are high, the monitoring effect is good, the easiness by interference is avoided, and the deformation can be stably monitored by measuring the deformation components of the two-dimensional surface in the horizontal and vertical directions.

The invention discloses a distributed optical fiber fence intrusion detection and location method based on a phi-OTDR (Optical Time Domain Reflectometer), and the method comprises the following steps of: firstly, subtracting an acquired ith signal by an acquired (i-1)th signal to obtain a preprocessing monitoring signal; secondly, carrying out at least four-layer wavelet decomposition on the preprocessing monitoring signal by adopting a plurality of wavelet functions; thirdly, judging whether actual intrusion exists according to the consistency of distribution positions of maximum-wavelet mode maximums in all scale signals; fourthly, judging that the actual intrusion exists if the distribution positions of the maximum-wavelet mode maximums in at least three scale signals are consistent; fifthly, corresponding multiplying the scale signals in which the intrusion exists and the distribution positions of the maximum-wavelet mode maximums are consistent to obtain a composite signal of which pseudo maximums are inhibited and mode maximums at a catastrophe point are enhanced, using a position corresponding to the maximum-mode maximum in the composite signal as a position of the determined intrusion point, determining the intrusion generation and the intrusion position by combining various composite signal judgment results of wavelet multi-scale analysis according to the majority voting criterion.

The invention discloses an optical signal to noise ratio (OSNR) monitoring device and monitoring method, comprising an optical amplifier (1), a first polarization control element (2), a circulator (3), a coupler (4), a nonlinear optical element (5), an attenuator (6), a second polarization control element (7), a first power meter (8) and a second power meter (9). The invention further discloses an OSNR monitoring method using the device, comprising the following steps: optimizing the polarization control elements to obtain working conditions of the linear area of the device; describing the power transmittance ratio of a transmission end to a reflection end of the monitoring device; fitting the relation between an OSNR and an output power by using a least square method; and back-calculating the OSNR by the output power according to the relation. The device and method disclosed by the invention are suitable for high-speed optical communication system. The device and method are compared with the prior scheme, the flexibility and monitoring range are improved obviously.

The invention discloses a slope stability monitoring and landslide warning and forecasting method based on an all-optical fiber sensing network. A number of drill holes are drilled in a direction perpendicular to a potential sliding surface or a joint surface and a bedrock surface in the top and surface of a rocky soil slope. An all-optical fiber integrated gauging pipe is buried in each drill hole. All optical fibers are mutually welded to form the all-optical fiber sensing network which is connected with an optical fiber demodulator to measure the strain and temperature distribution of each optical fiber. On the basis of early monitoring results, the vertical strain eigenvalue of the slope is selected, and the safety factor of the slope is acquired. The empirical relationship between the vertical strain eigenvalue and the safety factor is acquired. According to the measured result of the vertical strain eigenvalue, the safety factor of the slope is estimated, and warning and forecasting of slope instability are realized. Based on the optical fiber monitoring data, the process of birth, occurrence and development of the potential sliding surface of the slope and the position of a multi-level potential sliding surface can be accurately identified.

The invention discloses a manufacturing technology of a glass fiber / epoxy resin composite material substrate type fiber bragg grating sensor. The manufacturing technology comprises the steps that glass fiber / epoxy resin prepreg is procured to prepare a glass fiber / epoxy resin composite material substrate; a fiber bragg grating is fixed to the glass fiber / epoxy resin composite material substrate; the glass fiber / epoxy resin composite material substrate fixed with the fiber bragg grating is covered with a dry-state glass fiber cloth, vacuum aided filling of liquid epoxy resin is performed, and secondary curing molding is performed. The manufacturing technology adopts the secondary curing molding in the packaging process, the interlayer interface strength is remarkably improved, accordingly the testing precision and stability of the fiber bragg grating sensor are improved, batch production of the fiber bragg grating sensor can be achieved, and the manufacturing technology has wide market prospect and huge economic benefit.

The invention discloses a thin film sensor array, which is characterized by comprising a plurality of concentric annular thin film sensors, wherein an entire monitoring area is covered by the formed thin film sensor array; each annular thin film sensor mainly comprises three layers of structures which are micron thick, i.e., an insulating supporting layer, a conductive sensing layer and an encapsulated protective layer from bottom to top, wherein the insulating supporting layer is formed on the surface of a substrate and is integrated with the substrate; the conductive sensing layer is of an annular structure. The thin film sensor array disclosed by the invention has the beneficial effects that potential monitoring is carried out on the thin film sensor array which is integrated with a metal structure accurately in crack initiation and expansion stages, thus realizing quantitative and real-time monitoring on a full process of structure fatigue crack expansion; the thin film sensor array easily realizes integrated design and integration with the metal structure and is widely applicable to real-time monitoring of typical metal structure. The thin film sensor array is high in sensitivity, adjustable in monitoring precision, wide in monitoring range, low in power consumption, free from signal conversion and high in comprehensive cost effectiveness.

The invention discloses a method and system for vehicle operation monitoring, parameter measurement and calculation and overload monitoring. A monitoring method used when a vehicle is controlled by a power device to run is characterized by comprising the following steps of obtaining the joint operation values of a measurement and calculation object of the vehicle; judging whether the power transmitting condition of the vehicle is abnormal or not according to the obtained joint operation values and reference values of the measurement and calculation object, wherein the measurement and calculation object is any parameter selected from the vehicle mass of the vehicle, a source dynamic parameter and a system running parameter, and the joint operation values are obtained through calculation by using vehicle motion balance as a principle; and if the judging result is that the power transmitting condition of the vehicle is abnormal, starting a set power transmitting exception handling mechanism.

A device for monitoring optical network performances comprises a coupler (1), a filter (2), a first light intensity detection element (3), a second light intensity detection element (4), a first spectrum analyzer (5), a second spectrum analyzer (6) and a division operation unit (7). According to the device and a method for monitoring optical network performances, in a high-speed dynamic reconfigurable optical add and drop multiplexer, a radio frequency (RF) spectrum technology is used for achieving a chromatic dispersion (CD) monitoring technology of insensitive polarization mode dispersion (PMD), and CD and PMD can be monitored independently and simultaneously. The method is simple to implement, the device structure is simple, the detection bandwidth is low, a transmitter is not needed to be modified, the monitoring sensitivity is improved apparently, and the monitoring range is increased.

The invention discloses a click chemistry-based tumor marker probe, a preparation method and application. The tumor marker probe comprising a click reaction module with a tumor-specific factor and a click reaction module with a fluorescent marker is designed using reaction characteristics of click chemistry, such as high selectivity, high efficiency and high speed, and the two click reaction modules may be combined quickly through click reaction. The tumor marker probe is efficient in quickly combining to tumor tissues or cells, the life of the probe in viable tumor tissues and its detection time are effectively prolonged, the problem that an existing probe has poor specificity is effectively solved, and a new direction is provided for the in-vivo optical molecular imaging and live cell imaging of tumors as well as further targeted diagnosis and biological study of tumors.

The invention provides an online monitoring and warning method for a protective relaying direct-current operating circuit. The direct-current operating circuit comprises a closing circuit and a tripping circuit. The online monitoring and warning method includes steps of establishing a closing circuit monitoring branch and a tripping circuit monitoring branch respectively; selecting components and setting parameters in the closing circuit monitoring branch and the tripping circuit monitoring branch; detecting current flowing through the closing / tripping circuit monitoring branch to be compared with disconnection alarm current of the closing / tripping circuit, and judging whether the closing / tripping circuit is disconnected or not. The current flowing through the closing / tripping circuit monitoring branch can be monitored online by setting up the closing / tripping circuit monitoring branch, and complete monitoring of the tripping and closing circuits is realized by judging whether circuits are disconnected or not according to the current; by the online monitoring and warning method, all-condition complete monitoring can be realized without influencing normal operation of the system.

The invention provides an online monitoring device for power reactor vibration. The device includes a monitoring parameter sensor used for monitoring vibration and voltage and current signals of the power reactor in a work state; a signal processing module used for receiving signals monitored by the monitoring parameter sensor and performing amplification, filtering and synchronous digital-analog conversion processing after performing synchronous acquisition on the signals; a signal data reading module used for real-time reading of vibration and voltage and current signals which undergo the amplification, filtering and synchronous digital-analog conversion processing; a GSM data communication module used for monitoring information, which is read by the signal data reading module in a real-time manner, and forming vibration waveforms and current and voltage waveforms through the information for transmission so as to perform map display and data analysis; and an analysis display and alarm module used for obtaining waveform data of the vibration and waveform data of the current and voltage from the GSM data communication module for rapid anti-aliasing Fourier transform processing and continuous real-time display.

A space-borne ionospheric scintillation monitoring device utilizing GPS signal phase changes, including navigation and positioning channels, ionospheric monitoring channels, navigation and positioning data processors, ionospheric monitoring data processors and high-stable crystal oscillators, positioning receiving antennas and ionospheric Antennas for satellite positioning and ionospheric scintillation monitoring, data processing of navigation signals received by GPS satellite navigation receivers to obtain ionospheric scintillation detection parameters, obtain ionospheric distribution, and improve ionospheric scintillation and disturbance detection levels. The device can make full use of the global coverage and continuous uninterrupted characteristics of GPS satellite navigation signals to improve the monitoring ability of the atmospheric ionosphere. Atmospheric ionospheric scintillation monitoring real-time and global coverage.

The invention relates to a wavelength scanning optical fiber laser device. A scanning filter, a first optical fiber isolator, optical fiber amplifiers and a second optical fiber isolator are in closed-loop connections in turn and form a light wave passing loop; a first directional coupler is connected to the light wave passing loop and is provided with a scanning laser output end, and preferably, the first directional coupler is connected between the scanning filter and the connecting end of the first optical fiber isolator, between the first optical fiber isolator and the connecting ends of the optical fiber amplifiers, or between the connecting ends of two optical fiber amplifiers; the scanning filter is a scanning filter based on FP cavity piezoelectric ceramic drive or a scanning filter based on a micro electromechanical technique; and the optical fiber amplifiers are rare-earth doped optical fiber amplifiers or semiconductor optical fiber amplifiers. The invention also provides an optical fiber sensing system adopting the wavelength scanning optical fiber laser device as a light source. The wavelength scanning optical fiber laser device and the optical fiber sensing system have smart design, greatly reduce the processing difficulty and cost of the optical fiber sensing system, and can achieve multi-channel cascade connection.

An angular-displacement underwater settlement gauge comprises a piston-type displacement transmission device; a lower casing pipe and an upper casing pipe are disposed on the piston-type displacement transmission device; an extension rod is connected with the lower part of the piston-type displacement transmission device; the lower end of the extension rod is an anchoring point; a measuring box is connected with above the piston-type displacement transmission device; a settlement amount electric measurement device and an A / D switch device are disposed in the measuring box; a steel pipe is connected with the upper end of the measuring box; a settlement broad is connected with the top end of the steel pipe; a transmission belt is disposed in the piston-type displacement transmission device; the settlement amount electric measurement device is connected with the upper end of the transmission belt; the settlement amount electric measurement device is connected with the A / D switch device; the A / D switch device is connected with a monitoring instrument through cables, wherein the monitoring instrument is disposed above far away from the settlement gauge. The settlement gauge has a simple structure, and can convert linear displacement into angular displacement to improve measurement precision and accuracy. The angular-displacement underwater settlement gauge has wide application scope, high monitoring precision and sensitivity, strong interference immunity for transmission signals, and high stability, can realize real-time visual display of the settlement values, and is simple in installation, and low in cost.

the invention provides a railway safety monitoring system and monitoring method. The system comprises one and more phase-sensitive optical time-domain reflectometers arranged along a railway, corresponding data processing units, coaxial cables, a first network photoelectric transceiver, a communication optical cable along the railway, a second network photoelectric transceiver, and a server. According to the system and method, the railway safety is monitored by employing the conventional communication optical cable, the cost is low, passive distributed detection is realized, electromagnetic interference resistance is achieved, the development of the field of the railway optical cable safety monitoring system is greatly promoted, and good guarantee is provided for monitoring of railway train operation, infrastructure safety, and illegal authorization construction.

The invention provides a magnetic-suspension wave detector. The magnetic-suspension wave detector comprises a shell, a fixed permanent magnet, a first diamagnetic body, a coil, a second diamagnetic body and a suspension permanent magnet, wherein the fixed permanent magnet, the first diamagnetic body, the coil and the second diamagnetic body are sequentially arranged at the inner part of the shell from top to bottom, the suspension permanent magnet is positioned in the coil, and the magnetic pole magnetisms of the fixed permanent magnet and the suspension permanent magnet facing each other are different. According to the magnetic-suspension wave detector provided by the invention, the gravity born by the suspension permanent magnet can be offset through an attraction force from the fixed permanent magnet to the suspension permanent magnet, and the suspension permanent magnet is guaranteed to be in a stable state through the diamagnetic bodies which are positioned at the upper part and the lower part of the suspension permanent magnet; and when the suspension permanent magnet shifts to optional one direction, a component force of a horizontal direction or a vertical direction of a resulting force born by the suspension permanent magnet is opposite to a shifting direction, thus the suspension permanent magnet can be quickly and accurately attracted to return to a balance position, and the sensitivity and the accuracy of monitoring are increased.

The invention relates to a monitoring method for a vehicle and a vehicle so that a problem that the state of operating the steering wheel by the hands of the driver can not be determined accurately based on the existing monitoring scheme can be solved. The monitoring method comprises: acquiring a real-time torque value of a steering wheel of a vehicle; acquiring a real-time angular velocity valueof the steering wheel of the vehicle; and determining a driver confidence level of the vehicle based on the real-time torque value and the real-time angular velocity value and thus determining whetherthe drive is in a hand-off driving state based on the driver confidence level. According to the invention, the driver confidence level can be determined comprehensively based on the real-time torquevalue and the real-time angular velocity value; and thus the acting force on the steering wheel by the drive is used as a determination base and the angular velocity parameter capable of reflecting the rotating state of the steering wheel is also combined for determination. Therefore, whether the drive is in a hand-off driving state is determined accurately; and the effectiveness of monitoring isimproved and the error rate of monitoring is reduced.

The invention discloses a water level monitoring device and method with an alarm function. The water level monitoring device comprises a mounting block, a cavity is formed in the mounting block, a first tuning fork is fixedly installed in the cavity, and a second tuning fork with the same vibration frequency as the first tuning fork is further fixedly installed at the upper end of the mounting block. A metal cover body covers the outer part of the second tuning fork in a sealing manner, the two fork arms of the second tuning fork are just not in contact with the inner wall of the metal cover body, and a through hole communicated with the cavity is also formed in the surface of the mounting block in the metal cover body. A longitudinal first mounting groove is formed in the bottom of the cavity, and an impact block used in cooperation with the first tuning fork is vertically connected into the first mounting groove in a sliding mode. Transmission can be rapidly triggered when the waterlevel is lower than a warning line, an alarm is given to remind a worker to make a response in time, a pure mechanical structure is adopted for transmission in the process, electric power consumptionis not needed, energy conservation and environmental protection are achieved, the monitoring sensitivity is higher, and use is more convenient.

The invention discloses a method and device capable of automatically eliminating PIPS an energy spectrum peak temperature drift. According to the processing method, a threshold automatically-adjusting circuit is applied to eliminate peak position drift of a PIPS detector caused by temperature change, threshold level of a pulse amplitude discriminator circuit is automatically adjusted in real time through the threshold automatically-adjusting circuit, the adjustment is carried out automatically according to the environmental temperature change, and it is guaranteed that alpha particle energy resolution is free of environmental influences. The device comprises the PIPS detector, a amplification circuit, an amplifying and forming circuit, the pulse amplitude discriminator circuit, a single-chip microcomputer, the threshold automatically-adjusting circuit and a temperature and humidity sensor; the whole device is simple in structure and convenient to operate; monitoring sensitivity is improved, and the requirement for continuous monitoring of a nuclear facility field can be met.

The invention discloses a method for detecting etching insufficiency of through holes. The method comprises the steps that a plurality of test modules are built on a semiconductor substrate, each test module simulates an SRAM device structure and comprises two simulation transmission gate transistors, two simulation pull-up transistors and two simulation pull-down transistors, the simulation transmission gate transistors, the simulation pull-up transistors and the simulation pull-down transistors are PMOS devices in an N well, and no grid electrode is formed on active areas of the simulation transmission gate transistors; a plurality of contacting holes are formed in each test module and filled with metal, and the contacting holes are at least connected with positions, corresponding to grid electrodes, in the active areas of the simulation transmission gate transistors; a metal interconnection line and a conduction through hole are formed on each contacting hole; the test modules are scanned through an electron beam defect scanner under a positive potential condition, and the etching insufficiency defects of the through holes of the test modules are detected according to the image feature pictures obtained through scanning. The method for detecting etching insufficiency of the through holes can effectively improve the capturing efficiency of the etching insufficiency defects.

The invention discloses an oil trace moisture on-line monitoring sensor. The oil trace moisture on-line monitoring sensor comprises a high polymer thin-film capacitor, a temperature sensor, a signal processing circuit board and a mechanical seal structure, wherein the high polymer thin-film capacitor and the temperature sensor are used for measuring the content and the temperature of oil trace moisture respectively, the signal processing circuit board is used for detecting and processing output signals of the high polymer thin-film capacitor and the temperature sensor and converting the output signals into content and temperature values of oil moisture, and the mechanical seal structure comprises a protection sleeve, a mechanical shell, a gold-plating wire, a connector member, a fixation screw, an end cover and the like and is used for supporting and protecting an inside structure and preventing pollution caused by entry of oil. According to the oil trace moisture on-line monitoring sensor, the purpose of real-timely monitoring aviation oil moisture is achieved, and the oil trace moisture on-line monitoring sensor has the advantages of being small in size, light, simple in operation, and the like.

The embodiment of the invention provides a method and a device for monitoring polarization mode dispersion, an electronic device and a storage medium, applied to a receiving terminal of an optical fiber communication system. The method comprises the steps of generating pumping signal light with narrow bandwidth and low power consumption and auxiliary signal light based on the frequency of target signal light when the receiving terminal of the optical fiber communication device receives the target signal light; then coupling the pumping signal light and the auxiliary signal light to obtain detecting signal light; generating idle frequency signal light by utilizing the target signal light and the detecting signal light; and calculating a target power differential value between the power of the target signal light and the power of the idle frequency signal light so as to obtain a polarization mode dispersion value of the wireless optical fiber communication system. Through the scheme, the utilization rate and practicability of the optical fiber communication system are not only improved, but also the monitoring sensitivity and precision of the polarization mode dispersion are improved under the precondition of monitoring the polarization mode dispersion efficiently.

The invention relates to a microbial whole-cell luminescent reporting sensor for monitoring Hg<2+> pollution and a kit prepared thereby and an application. The microbial whole-cell luminescent reporting sensor for monitoring Hg<2+> pollution is a whole-cell luminescent sensor engineering bacterium which is constructed by importing a merR-Pt-containing anti-mercury gene regulating region and egfp genes into a host which is a highly anti-mercury bacterium. The kit comprises an immobilized cell culture which contains the bacterium and a special buffer which is suitable for testing. The sensor kit can be used for specifically and sensitively monitoring pollution of heavy metal Hg<2+> which is the strongest in toxicity in a soil, river, lake, underground water and municipal wastewater treatment system. Compared with the prior art, the microbial whole-cell sensor provided by the invention is strong in specificity and adaptability, convenient to use and high in monitoring sensitivity and can be used for high throughput online monitoring.

The invention discloses a drainage liquid rapid monitoring system special for thyroid and mammary gland surgical postoperation.By using a gas pressure sensor, the monitoring flexibility is high, the size is small, installation and debugging are convenient, and liquid in a drainage ball can be monitored in real time; operation is simple, and gas pressure monitoring of the negative drainage ball can be completed without changing an existing negative pressure drainage ball structure; intelligent monitoring of the drainage technology is achieved, the drainage situation can be monitored in real time, the current drainage amount in the drainage ball is calculated, nurses are helped to efficiently complete the work such as observation and measurement of drainage liquid, and the nursing workloads are greatly reduced; calculation is conducted for abnormal drainage of drainage liquid and falling, bending or blocking of a drainage pipe, effective and continuous monitoring is achieved, real-time alarming and reminding are achieved, it is ensured that medical workers find drainage liquid abnormity of patients in time, intervene processing is conducted as soon as possible, and at the current stage at which the nursing manpower resource is tight, the system can effectively assist medical workers in working, improve the medical care quality and achieve the aim of postoperative safety of patients.

The invention discloses a detection method for under-etching of through holes. The method comprises the following steps: a plurality of test modules are built on the substrate of a semiconductor, each test module simulates an SRAM device structure and comprises two simulation transmission gate transistors, two simulation pull-up transistors and two simulation pull-down transistors; the simulation transmission gate transistors, the simulation pull-up transistors and the simulation pull-down transistors are NMOS devices in a P trap, and a grid electrode is not formed in the active area of each simulation transmission gate transistor; a plurality of contact holes filled with metal are formed in each test module; the contact holes are connected with the position, corresponding to the grid electrode, of the active area of each simulation transmission gate transistor at least; metal interconnecting wires and conductive through holes are formed in the contact holes; test modules are scanned under the positive potential condition by an electron beam defect scanner, and the defect of under-etching of through holes of the test modules is detected according to image characteristic patterns obtained through scanning. The method provided by the invention can increase the capturing rate of the defect of under-etching.