123results about "Material breakdown voltage" patented technology

The invention discloses a laboratory instrument data automatic acquisition and analysis method and system, and relates to the technical field of laboratory instrument acquisition and analysis, and the method comprises the steps: obtaining sample identification information, automatically sorting and distributing the sample identification information to different analyzers, uploading detection data to a central database in real time, and associating a sample number, a detection timestamp and an instrument number; the method comprises the following steps: constructing a multi-dimensional feature space based on historical detection data, performing sub-cluster division by adopting a density clustering algorithm, establishing a cross-index logic constraint relationship in combination with an expert rule base, mapping real-time detection data to the multi-dimensional feature space, judging a data exception type according to sub-cluster affiliation and the logic constraint relationship, and when judging that the data is exceptional, judging that the data is abnormal. And triggering a secondary detection process, automatically dispatching a mechanical arm to send the sample back to a specified instrument to execute differentiated reinspection operation, and generating a comprehensive report containing detection process tracing. According to the invention, the automation level of detection is improved, the labor cost is reduced, the detection quality and efficiency are improved, and the laboratory detection work efficiency is improved.

The invention relates to a continuous production process of a wrapping preforming and squaring integrated film-covered wire, and belongs to the technical field of composite material forming. Comprising a pay-off machine, a coating machine, a squaring machine, a first lead assembly, a first pressing assembly and a curing assembly, and the production process comprises the following steps that S10, raw materials are paid off; step S20, coating with an adhesive tape; step S30, carrying out pre-pressing treatment; and S40, winding output and wire rod squaring treatment are carried out. The technical problems that in the prior art, wire rods need to be wound and output through a wire winding machine between the wire rod coating process and the die pressing process, multiple times of wire arrangement are needed, production is not continuous enough, and consequently the production efficiency is reduced are solved.

The invention discloses an electric spark nondestructive testing evaluation method for the integrity of a waterproof layer of a cable trench, and belongs to the technical field of nondestructive testing, and the method comprises the following steps: applying a multi-frequency electric signal through a preset moving electrode; the initial contact pressure of the moving electrode and the surface of the waterproof layer is obtained in real time, the pressure of the contact position of the moving electrode is adjusted, an electric spark signal generated at the defect position of the cable trench waterproof layer by a multi-frequency electric signal applied by the moving electrode is captured, and characteristic parameters of the electric spark signal are extracted to generate current electric spark characteristic data; utilizing the current electric spark characteristic data to distinguish defect types so as to generate a defect evaluation result; and outputting defect distribution information and triggering an acousto-optic alarm according to a defect evaluation result. According to the method, a detection mode of combining multi-frequency electric signal excitation and electric spark signal feature extraction and analysis is adopted, waterproof layer defect types can be distinguished, the severity of the waterproof layer defects can be evaluated, and the detection accuracy is improved.

The invention discloses a cable accessory interface breakdown voltage testing device and method. The cable accessory interface breakdown voltage testing device comprises a conductor, a first shrinkage pipe, a second shrinkage pipe, a first electrode, a second electrode and voltage detection equipment. And the first shrinkage pipe wraps the outer wall of the conductor after being shrunk. And the second shrinkage pipe covers the outer wall of the first shrinkage pipe after being shrunk. The first electrode and the second electrode are arranged between the first shrinkage pipe and the second shrinkage pipe, and the first electrode and the second electrode are arranged at intervals in the axial direction. The voltage detection device is connected with the first electrode and the second electrode. According to the invention, the interface breakdown voltage of the cable accessory can be detected quickly, economically, effectively and accurately.

The invention relates to the technical field of electrical performance testing, and discloses a multi-class nonferrous metal breakdown voltage testing device, system and method. The testing device comprises a testing groove provided with a plurality of independent clamping grooves, a temperature and humidity regulation and control system, an electrode module, a power module and a data acquisition module, and high-precision breakdown voltage testing of multiple samples in a constant environment is achieved through multi-channel synchronous testing, temperature and liquid level dynamic control, symmetrical electrode layout and high-speed data acquisition. The system is integrated with a central control unit, the boosting rate is automatically set according to sample parameters, multiple channels independently boost and synchronously collect breakdown data, and a double-threshold algorithm is adopted to judge breakdown events in real time. The method comprises the whole process of solution preparation, sample installation, electric field optimization, boost control and data judgment. Compared with the prior art, the testing efficiency and the measuring precision are improved, the environmental interference is reduced, and the method is suitable for batch detection and quality control of tantalum, niobium and oxide materials of the tantalum, the niobium and the oxide materials of the tantalum and the niobium.

The invention discloses an automatic oil injection device and method for insulating oil breakdown voltage detection, and relates to the technical field of insulating oil detection.The automatic oil injection device comprises an oil injection assembly, a breakdown voltage detection assembly, a temperature measurement and control module and an automatic oil injection module, and the oil injection assembly comprises an oil injection module, an oil cup and an insulating oil liquid level control module; the breakdown voltage detection assembly comprises a to-be-detected oil sample volumetric flask, a filtering module, a first peristaltic pump and a breakdown voltage tester; the temperature measurement and control assembly comprises an oil temperature measurement module and a temperature control module; according to the invention, the traditional manual removal time is shortened, the injector is not easy to damage, the risk of cutting a detector is also avoided, and dangerous factors are reduced in the detection process.

The invention provides a test system and method for simulating in-situ reservoir electric detonation fracturing through gas-liquid coupling pressure application. The test system comprises a pressure chamber used for installing a test piece, a stress loading device, a gas-liquid coupling device and a high-voltage electric detonation fracturing device with a discharge electrode. A detonation hole is formed in the top of the test piece; the stress loading device is connected with the pressure chamber and is used for applying axial pressure and confining pressure to the test piece in the pressure chamber to simulate ground stress; the gas-liquid coupling device can inject water, gas, water and gas into the pressure chamber; and a discharge electrode of the high-voltage electric detonation cracking device can be arranged in a detonation hole of the test piece to crack the test piece. The device has the characteristic of being capable of applying axial pressure and confining pressure, controllable explosion energy can be achieved, coupling of multiple physical fields and high accuracy of energy output are guaranteed, and self-water injection, self-gas injection and up-down water pumping and draining are achieved through the gas-liquid coupling device; and accurate and in-depth research on the hole fracture development law, gas migration, permeability and the like after the in-situ reservoir high-voltage electric pulse technology is realized is facilitated.

The utility model discloses a Teflon pipe rapid electric spark detection device, and relates to the Teflon pipe technology field, the Teflon pipe rapid electric spark detection device comprises a base plate, protection shells, and feeding ports, the protection shells are fixedly connected to the top of the base plate, and the feeding ports are arranged on two sides of the two protection shells; the teflon pipe rapid electric spark detection device comprises a bottom plate, the middle of the top of the bottom plate is provided with a detection structure, the detection structure is provided with a fixing ring, the fixing ring is fixedly connected to the top of the bottom plate, and one end of the fixing ring is hinged to a rotating ring. The electric spark detection equipment can generate electromagnetic radiation during high-voltage working, electromagnetic shielding can protect operators from being damaged by the electromagnetic radiation, meanwhile, external electromagnetic interference is prevented from damaging electronic elements of the equipment, electromagnetic interference sources in an industrial field environment are more, the electromagnetic shielding provides a relatively clean electromagnetic environment, and the electromagnetic shielding can be used for protecting the operators from being damaged by the electromagnetic radiation. And stable operation of equipment is ensured.

The invention relates to the technical field of production and detection of high-insulation magnesium oxide powder, in particular to a production and detection method and system of high-insulation magnesium oxide powder, which are used for solving the problems that multiple performance indexes are difficult to cooperatively detect and the regulation and control response of process parameters is lagged. Key performance indexes such as particle uniformity, insulating strength and material density are collected in real time through a sensor array, and operation state information is constructed. And calculating a priority coefficient of each index based on a dynamic weight distribution algorithm, wherein the priority coefficient is used for dividing production line detection segments. And constructing a time sequence model for each segment, introducing an ARIMA method to predict a performance trend, and generating a deviation evaluation index in combination with an ideal process curve. And identifying a performance abnormal region according to an evaluation result, constructing a PID closed-loop control mechanism based on a dominant index, adjusting key process parameters in real time, and realizing dynamic optimization regulation and control on the target segmented region.

The utility model relates to a glass-lined pressure vessel inspection device which comprises a telescopic rod and a multifunctional detection unit, one end of the telescopic rod is a detection end, and the other end of the telescopic rod is a handheld end; the multifunctional detection unit is fixed on the two sides of the detection end of the telescopic rod and comprises a glass lining coating thickness meter, an oxygen and explosion meter and a direct-current high-voltage detection probe rod electric brush; one side of the detection end is provided with the direct-current high-voltage detection feeler lever electric brush, and the other side of the detection end is provided with a glass lining coating thickness meter and an oxygen and explosion measuring instrument. Compared with the prior art, the device can detect various problems at the same time, improves the detection efficiency, and is simple in structure and convenient to carry.

The invention belongs to the technical field of generator stator coil materials, and particularly relates to a method and a system for evaluating aging resistance of a generator stator coil in a high-altitude environment. The method is based on research on service characteristics and evolution laws of a generator stator coil in a high-altitude environment; the aging resistance of the generator stator coil is evaluated through the following indexes for the first time: testing the breakdown voltage of the stator coil, the concentration of volatile organic compounds detected under the thermo-oxidative aging condition, the heat conductivity coefficient, the specific surface area of solid substances, the porosity and the liquid adsorption performance. The evaluation method provided by the invention has the advantages of accuracy and rapidness, and has a good application prospect.

The invention relates to an arc contact multi-factor coupling test device and method and a service performance evaluation method, and the arc contact multi-factor coupling test device comprises a multi-environment coupling test box body which simulates the use environment of an arc contact; the contact arc extinguishing test platform is arranged in the multi-environment coupling test box body and is used for fixing the arc contact so as to simulate the large-current arc breaking process of the contact; the electrical parameter control system is arranged on one side or multiple sides of the multi-environment coupling test box body and used for controlling electrical parameters in the test process; and the control and data acquisition module is respectively connected with the multi-environment coupling test box body, the contact arc extinguishing test platform and the electrical parameter control system and is used for setting test parameters and acquiring test data. According to the test equipment, an electric, thermal, mechanical and environmental multi-field coupling technology is adopted, a highly-simulated test platform is constructed, and the operation state of the contact under the actual working condition can be comprehensively and accurately evaluated.

The invention provides a multifunctional electrode for an oil oxidation test, and an oil oxidation test system and method. The multifunctional electrode comprises a main body frame, an electrode plate, a metal coil, a wiring terminal and a mounting assembly, the main body frame comprises an upper end cover, a lower end cover and a plurality of stand columns, and an internal cavity is formed among the three; the wiring terminals comprise two first wiring terminals, two second wiring terminals and a plurality of third wiring terminals; the two first wiring terminals are fixed with the two metal plates of the electrode plate; the two second wiring terminals are connected with the metal coil; the third wiring terminal is connected with an electronic component; the mounting assembly is located in the internal cavity. The multifunctional electrode provided by the invention simulates the oil service condition in a complex scene to a great extent, realizes the oxidation decay test of oil under the coupling action of multiple physical fields such as electricity, magnetism, heat, oxygen and metal, and also realizes the synchronous monitoring of material compatibility, compatibility of electronic components and oil, corrosion and electrical performance in the oil oxidation process.

This invention relates to the field of simulation verification device technology, and discloses an environmentally friendly insulating gas simulation verification device, including a housing with an internal cavity, and two shells disposed inside the cavity, each capable of rotating about its own central axis. The invention utilizes the rotation of the shells around their central axes to move a first and second protrusion along the central axis of the shells, causing them to protrude a certain distance from the surface of the shells. This results in an uneven electrode surface formed by the three components. By gradually adjusting the voltage and observing the current change between a pair of electrodes, the device can detect the voltage at which SF6 gas breaks down and loses its insulating properties. This design, which creates an uneven electrode surface, accurately reflects the usage scenario, ensuring the accuracy of the test results and enabling the safe use of SF6 gas.

The invention discloses a compatibility evaluation method and device of a transformer structure material and an insulating liquid, electronic equipment and a storage medium, and belongs to the technical field of electrical insulation detection.The method comprises the steps that compatibility evaluation indexes of the transformer structure material and the insulating liquid are obtained; index characteristics corresponding to the compatibility evaluation indexes are calculated; wherein the index characteristics comprise trend intensity, fluctuation characteristics and mutation characteristics; according to the index characteristics, calculating a weight coefficient corresponding to each compatibility evaluation index, according to the index value of each compatibility evaluation index and the corresponding weight coefficient, calculating a compatibility comprehensive score of the transformer structure material and the insulating liquid, and then according to the compatibility comprehensive score, determining the compatibility of the transformer structure material and the insulating liquid. Therefore, by implementing the method, the problem that the compatibility of the transformer structure material and the insulating liquid cannot be evaluated in the prior art can be solved.

Disclosed in the present invention are an aging performance influencing factor determination method and apparatus for a solid insulating material, a terminal device, a storage medium and an aging performance evaluation method. The aging performance influencing factor determination method comprises: on the basis of the number of aging performance influencing factors to be selected of a solid insulating material and the number of corresponding factor levels, determining an orthogonal experimental solution; acquiring the breakdown strength of the insulating material under different factor levels of each of said aging performance influencing factors, the breakdown strength being obtained by means of the orthogonal experimental solution; on the basis of the breakdown strength, calculating the significant effect value of each of said aging performance influencing factors; and comparing the significant effect value of each of said aging performance influencing factors with a preset significance level, and determining, as a selected aging performance influencing factor, an influencing factor the corresponding significant effect value of which is lower than the preset significance level. The present invention can be used to effectively reduce the number of factor determination experiments, thereby saving time and resources.

The invention discloses an insulator impact breakdown voltage measurement system and method, and belongs to the field of electrical measurement. The system comprises an upper computer, a plurality of cameras, a high-voltage power supply and an insulator testing device, the insulator testing device comprises a closed cavity, a disc platform used for placing a plurality of insulators to be tested, a high-voltage electrode and an ionic wind module. The upper computer is used for controlling the ion wind module according to preset ion current parameters after the closed cavity is filled with the insulating gas, so that the ion wind module releases positive and negative ion current; the upper computer is also used for controlling the high-voltage power supply to supply power to the high-voltage electrode which forms a measuring loop with each insulator to be measured, so that the high-voltage electrode applies impact breakdown voltage to each insulator to be measured; and the upper computer is also used for obtaining an impact breakdown voltage measurement result of the insulator to be tested according to the number of the discharge channels corresponding to the discharge images of the cameras around the insulator testing device. According to the invention, the efficiency and accuracy of insulator impact breakdown voltage measurement are improved.

The utility model discloses an electric spark tetrafluoro material detection device, relates to electric spark detection field, including base and top plate, the bottom of base is provided with drive assembly, and the output end of drive assembly is provided with the sliding plate, the sliding plate is symmetrically provided with the clamping plate in sliding mode, the inside of clamping plate is rotatingly provided with the placing plate, the placing plate is provided with the clamping plate. A clamping plate is arranged on the base, a containing groove is formed in the clamping plate, a clamping sleeve is arranged on the clamping plate, an inserting rod is connected to the inner side of the clamping sleeve, a toothed rod is arranged in an interlayer of the clamping plate in a sliding mode, and an inserting hole matched with the inserting rod is formed in the toothed rod. The PTFE material is driven to slide upwards under the action of the air cylinder, the clamping plates clamp the two ends of the PTFE material in the process, and then the toothed bar is driven to slide downwards under the action of the insertion rod and the insertion hole, so that the bottom end of the PTFE material is completely exposed at the top of the detection assembly; and in the process, the PTFE material is quickly clamped.

The application discloses a lightning stroke event online guided wave monitoring method and device for a composite material structure, and comprises the following steps: arranging a plurality of piezoelectric sheets in a composite material structure to be monitored to form a sparse piezoelectric array; when the outer surface of the composite material structure to be monitored is struck by lightning, lightning impact force guided wave response mechanical quantities are excited, and the generated mechanical quantities are conducted to the piezoelectric sheets; the lightning impact force guided wave response mechanical quantities are converted into lightning impact force guided wave response signals; the lightning impact force guided wave response signals are transmitted to a data acquisition module through an online sensing mode; the lightning impact force guided wave response signals are subjected to direct current component removal and filtering pretreatment; and through a lightning impact force guided wave response signal imaging monitoring mode of the sparse piezoelectric array, lightning attachment point impact force passive imaging results are constructed. The lightning stroke event online guided wave monitoring method and device can not only improve the quality of lightning piezoelectric guided wave response signals, but also can perform high-precision positioning and imaging on lightning attachment points.

This invention discloses a method for testing the insulation strength of the inner surface of ceramics, belonging to the field of ceramic materials technology. The sealing component consists of a ceramic part and metal cover plates. An inner platform is provided on the inner wall of the ceramic part, and two metal cover plates are sealed to the inner platform with solder. An intermediate cavity is left between the ceramic part and the metal cover plates. During testing, measuring electrodes are first connected to the metal cover plates, and then the sealing component is placed in an insulating medium for power frequency withstand voltage testing. The initial test voltage starts from 30-90 kV, with a stabilization time of 1-2 minutes. The voltage is increased by 1-10 kV each time until the ceramic part breaks down at the surface. The ratio of the breakdown voltage to the height of the inner platform is used to obtain the insulation strength of the inner surface of the ceramic part. Because the distance between the inner and outer surfaces of the ceramic part is much smaller than that between the outer and outer surfaces, and the outer surface is immersed in the insulating medium, the inner surface breaks down preferentially during measurement, thus effectively measuring the insulation strength of the inner surface of the ceramic part.

For non-destructively measuring the yield strength of a metallic member using magnetic incremental permeability, a quasi-static excitation magnetic field is applied to two points of the metallic member, while a small alternating magnetic field generated by a transmitting coil is applied to the metal member. Intensity of the quasi-static excitation magnetic field applied to the metallic member is measured using a Hall sensor. The magnetic field induced by the magnetized metallic member is detected using a sensing coil. Using signals from the Hall sensor and the sensing coil, a reversible permeability (MIP) of the metallic member is obtained. A grain size of the metallic member is obtained from the relationship between the reversible permeability and the grain size of the metallic member, and the yield strength of the metallic member is calculated using the grain size. The grain size and yield strength of the metallic member can be measured non-destructively.

A method of forming an integrated circuit on a substrate is described herein. The method includes forming a first doped region of a detection structure on the substrate, the first doped region comprises a first doped conductivity type. The method forming a capacitor of the detection structure, which includes forming a second doped region of a second conductivity type opposite the first doped conductivity type, the second doped region surrounded by the first doped region. The second doped well comprises a top surface area smaller than a top surface area of the first doped region. The method includes performing parametric testing on the capacitor over a plurality of breakdown voltages. The method includes determining the gate oxide integrity of the capacitor based on the parametric testing over the plurality of breakdown voltages.

The invention relates to the technical field of cable manufacturing, and provides a multi-core PVC cable splitting and integrating device which comprises a pay-off system, a splitting and integrating system and a winding system. The pay-off system comprises a base, a plurality of pay-off racks and a plurality of driving parts; the pay-off racks are rotationally connected to one side of the base under the driving of the driving parts, and the multiple pay-off racks are arranged at intervals in the length direction and the width direction of the base; the separating and combining system comprises a rack, a first guide assembly, a dispensing assembly and a heating assembly; the first guide assembly is used for guiding core wires led out by the pay-off rack, the dispensing assembly is used for dispensing and fixing all the core wires, and the heating assembly is used for shortening the drying time of glue; and the winding system is used for winding the cable. On the basis, the microwave coaxial performance can be met, and meanwhile the requirement for manufacturing multi-core PVC cables of different lengths can be met. In addition, the invention further provides a manufacturing process of the multi-core PVC cable.

A fluid electrical probe includes a body portion housing a cleaner, a head portion forming a gap, an electrode disposed in the gap, and a temperature sensor disposed in the gap. The cleaner is extendable into the gap to clean the electrode and the temperature sensor. The body portion comprises a handle configured to be gripped by an operator.

The present invention relates to an analysis device (1) for measuring electrical properties of an insulating material which analysis device (1) comprises a sample releasing unit (14), a sample receiving unit (15), an electrical drive unit for moving a sample from the sample releasing unit (14) to the sample receiving unit (15), a first electrode (11) and a second electrode (12), a voltage source (10) electrically connected to the first electrode (11), and a control unit (16). The present invention further relates to a method of analyzing electrical properties of an insulating material. The present invention also relates to a method of analyzing the surface potential decay (SPD) of an insulating material.

The present invention belongs to the field of battery short - circuit detection, involves data analysis technology, and is used to solve the problem that the prior art cannot verify the short - circuit detection results in combination with risk analysis. Specifically, it is a lithium - battery short - circuit diagnosis and detection method and system, including a diagnosis and detection platform, which is communicatively connected to a short - circuit detection module, a risk assessment module, a factor investigation module, an optimization analysis module, and a storage module; the short - circuit detection module is used to perform short - circuit detection and analysis on the lithium battery: generate a detection period and divide the detection period into several detection time periods, mark the lithium battery as the detection object, and mark the detection time periods as short - circuit normal time periods or short - circuit abnormal time periods through the short - circuit coefficient DL; the present invention can perform short - circuit detection and analysis on the lithium battery, collect and calculate the operating parameters of the lithium battery in each detection time period to obtain the short - circuit coefficient, feedback the short - circuit probability of the lithium battery through the short - circuit coefficient, and then differentially mark the detection time periods.

The application discloses a kind of for cable trench waterproof layer integrity electric spark nondestructive testing evaluation method, belong to nondestructive testing technical field, it includes by preset mobile electrode applies multi-frequency electric signal;Real-time acquisition mobile electrode and the initial contact pressure of waterproof layer surface, adjust the pressure of mobile electrode contact position, capture the electric spark signal generated by the multi-frequency electric signal applied by mobile electrode at the defect of cable trench waterproof layer, extract the characteristic parameter of electric spark signal to generate current electric spark characteristic data;Current electric spark characteristic data is used to distinguish defect type, to generate defect evaluation result;According to defect evaluation result, output defect distribution information and trigger sound light alarm.The application adopts multi-frequency electric signal excitation, electric spark signal feature extraction and analysis combined detection mode, can distinguish waterproof layer defect type, evaluate its severity, improve the accuracy of detection.

The invention discloses a hot-pressing defect detection method and system for a multi-layer anti-corrosion composite lining plate, and the method comprises the steps: putting the multi-layer anti-corrosion composite lining plate made of a PTEF plate, a PFA plate and a PET plate into a hot press, and executing a hot-pressing process; carrying out on-line electric spark detection and extracting key features from an on-line electric spark detection result; judging whether the multi-layer composite anti-corrosion lining plate has defects or not and the types of the defects according to the key features; automatically triggering a preset repair strategy or a high-level alarm according to a specific defect type after judging that the defect exists; and after the hot pressing process is finished, the multi-layer composite anti-corrosion lining plate is subjected to pressure maintaining and cooling to be below the preset cooling temperature, the multi-layer composite anti-corrosion lining plate is taken out and subjected to off-line comprehensive detection, and whether defects exist or not is judged again. The online quality monitoring system is integrated in the hot-pressing process, so that real-time quality feedback and process control are realized, zero defect of products is ensured, and the production efficiency is improved.

The invention discloses a ternary mixed insulating oil configuration evaluation device and evaluation method, and belongs to the technical field of transformer insulating oil evaluation. The evaluation device comprises a computer, an oil breakdown voltage detection device, an oil dielectric loss detection device, an oil viscosity measurement device, a device for detecting total hydrocarbon gas in oil and a heating device. The ternary mixed oil storage device is connected with each detection device; characterizing an insulating property state quantity through breakdown voltage, and characterizing a dielectric loss state quantity through dielectric loss; the viscosity state quantity is represented through the oil viscosity; the stable state quantity of the current ternary mixed insulating oil is formed through the total hydrocarbon content in the oil after breakdown; obtaining an evaluation coefficient according to the state quantity; according to the method, the interference of human factors is avoided, the evaluation result can reflect the configuration state of the ternary mixed insulating oil more actually, and the problem that the ternary mixed insulating oil prepared in different proportions cannot be comprehensively and systematically evaluated is solved.

The utility model discloses an insulating material detection device, which relates to the technical field of detection equipment and comprises a base, supports are fixedly connected to the bottom of the base close to four corners, a fixing plate is arranged at the top of the base, a lower electrode is fixedly connected to the top of the fixing plate, and a support is fixedly connected to the top of the fixing plate. The insulating material is fixed by arranging the fixing plates, the supports, the air cylinders, the pressing plates and other components, electric conduction detection is conducted on the insulating material through high-voltage breakdown between the upper electrode and the lower electrode, and the multiple fixing plates, the multiple supports and other components can detect multiple materials at the same time; and the size of the bracket can be adjusted through the screw rod and the movable block to be suitable for detection of materials with different sizes.