247results about How to "Simple sample preparation" patented technology

The invention discloses a device for testing the hardness, fracture toughness and residual stress of a brittle material with an indentation method, belonging to the technical field of material property representation. The device comprises a frame and an image acquiring system, wherein the frame is provided with an eye lens, a height-adjustable testing operation platform and an adjusting rotating wheel; a loading system is arranged in the frame, and comprises a fixing support base, a lever, a mandrel, a hanging rod, a middle main shaft and a second motor; and a first motor and the second motor of the loading system are connected with a computer through an I / O (Input / Output) control card. In the invention, the conventional digital image low-load Vickers hardness meter is improved, so that the micro-hardness of a material can be directly tested, and the fracture toughness and residual stress of an interface system of the brittle material and a brittle coating film material can be directly tested; and the device can be widely applied to departments such as industrial enterprises, universities, academies and the like for rapidly detecting relevant indexes.

An object of the present invention is to provide a medium; a specimen; a method for preparing the specimen; a method for observing the specimen; a sample cell; and an electron microscope capable of easily solving the problem of charge-up and further capable of observing a real shape or the like of a sample with a SEM, a TEM or the like. For the purpose of achieving the above-described object, the present invention uses an electrical conductivity-imparting liquid medium, for use in a microscope, which includes an ionic liquid as an essential component thereof and is impregnated into the entirety of a SEM or TEM sample or applied to the observation surface of a SEM or TEM sample to impart electrical conductivity at least to the observation surface of the sample. According to the present invention, the charge built up on the sample surface can be released simply by impregnating or coating the sample with the ionic liquid, and hence the problem of charge-up can be easily solved. Further, even when a sample impregnated or coated with the ionic liquid is placed under vacuum, the ionic liquid is not evaporated from the sample, and hence a biological sample can be observed as it is in an original shape.

The invention relates to a method for observing the in-situ morphologies of the nonmetallic inclusions in steel. The method is characterized by comprising the following steps: a metallographic specimen is prepared and a surface to be observed is polished to be a plane; the superficial electrolytic corrosion is performed on an electrochemical polishing apparatus, an electrolyte is as follows: 5% (v / v) HCl (hydrogen chloride)+5%(v / v) glycerol+1% (v / v) citric acid methanol solution, and the setup parameters of the electrochemical polishing apparatus are as follows: the current density is 0.02A to 0.10A / cm<2>, the electrolytic temperature is from below 15 DEG C to below 5 DEG C, and the electrolytic time is 20 to 40s; a rubber rod is utilized for slightly wiping off the corrosive products on an electrochemical polishing surface of a test sample after the electrochemical polishing, the surface of the test sample is dried by a blow drier, and the nonmetallic inclusions are highlighted on an electrolytic etched surface of the test sample, so that the true morphologies of the nonmetallic inclusions with the different dimensions are completely displayed; and the morphologies of the nonmetallic inclusions are observed by a scanning electron microscope and an energy disperse spectroscopy. The method for observing in-situ morphologies of nonmetallic inclusions in steel provided by the invention has the advantages that the sample is prepared simply, the period is short, the analysis speed is fast, and the constituents and the varieties of the nonmetallic inclusions can be determined accurately by observing the three-dimensional morphologies and dimensions of the nonmetallic inclusions.

The invention discloses a method for performing infrared spectroscopic analysis on the SBS modifier content of modified asphalt, which comprises the following steps of: acquiring transmittance spectrum of an SBS modified asphalt sample with the known SBS modifier content by using a Fourier infrared spectrometer; computing a relative ratio A of a peak area which only belongs to a characteristic infrared absorption peak of the SBS to a peak area which only belongs to the characteristic infrared absorption peak of matrix asphalt on the transmittance spectrum; performing a parallel test for multiple times to determine the corresponding standard A value of the SBS modified asphalt sample; performing an infrared spectroscopic transmittance spectrum test on the SBS modified asphalt sample to be tested to obtain the transmittance spectrum of the sample; computing the relative ratio of the areas of the corresponding absorption peaks of the sample; and comparing the relative ratio with the standard A value to determine the SBS content of the sample. The general infrared transmittance spectrum test technique is adopted, so the method has the advantages of simple sampling process, convenient and quick establishment of a measuring method, correct and credible quantitative result, high sensitivity, high repeatability and suitability for wide application.

The invention discloses a method utilizing the HPLC (High Performance Liquid Chromatography) to test seventeen phenol substances contained in grapes and oranges, which comprises the following steps: firstly, separating the peel and pulp of the oranges or the grapes; secondly, drying and crushing the peel and pulp, and adding DMSO (Dimethyl Sulfoxide) : methanol (1:1) or a methanol solution into the peel and pulp to execute extraction; thirdly, after the collection of supernatant fluid, repeatedly extracting and compounding the supernatant fluid to execute HPLC detection; and lastly, identifying the sorts of the grapes and the oranges according to different sorts, content analysis of various phenol substances measured in different producing areas, and different chemical compound contents. The method disclosed by the invention adopts the HPLC to synchronously separate and test the seventeen phenol substances, and achieves the test to the ingredients and contents of the seventeen chemical compounds in different sorts of fruits such as the orange and the grapes and in wine, is simple in the pretreatment of the sample and low in cost, can synchronously test the ingredients and the contents of the phenol substances in the fruits, fruit juices and fruit wine.

A signal-off-quantum-dot-based sensor for detecting the presence of a target molecule comprising: an aptamer probe having a nucleotide sequence which specifically interacts with the target molecule by sequence-dependent interaction, wherein the aptamer probe is sandwiched between (a) an oligonucleotide which is immobilized on the surface of a quantum dot (QD), and (b) a fluorophore-labeled oligonucleotide, wherein when the sensor is excited by an energy source: (i) in the absence of specific interaction between the target molecule and the aptamer probe, a baseline signal is emitted, and (ii) in the presence of specific interaction between the target molecule and the aptamer probe, a detection signal is emitted, wherein the baseline signal is greater than the detection signal, whereby the presence of the target molecule is detected.

The invention discloses a quantitative metallographic analysis method for a phase M23C6 of Super 304H steel. The quantitative metallographic analysis method comprises the following steps of (1) cutting, grinding, polishing, corroding and air-drying a test sample, wherein only the M23C6 in the obtained metallographic test sample is corroded, and all the other phases are not corroded; (2) performing photography through a scanning electronic microscope to obtain a clear shape and appearance image of the phase M23C6 in a metallographic grinding surface; (3) extracting and calculating the phase M23C6 in a metallographic structure shape and appearance image through image analysis software Image-Pro-Plus to finally obtain the volume percentage of the phase M23C6 in a material. The quantitative metallographic analysis method disclosed by the invention has the advantages that limitation to the shape and the size of the test sample is small, the sample preparation is simple, the operation is convenient, the observation range is large, and a statistical significance is achieved during calculation of the phase M23C6; furthermore, the quantitative metallographic analysis method is an ideal method for quickly, accurately and quantitatively analyzing the content of the phase M23C6 in the Super 304H steel.

The invention relates to an assessing test machine for tribological properties of a high polymer compound material. The assessing test machine comprises an airtight box and is characterized in that a transmission shaft is arranged on a box wall, wherein a shaft end of the transmission shaft extending out of the box is connected with a safety shaft, a torque meter and a servo motor in turn througha coupler; a rotating angle disc is mounted on the safety shaft; one end of the transmission shaft inserted into the box is connected with a sample shaft through a universal crossing coupler; an upper sample clamp and a lower sample clamp are arranged around the sample shaft; a force transfer rod is connected with the upper sample clamp; one end of the force transfer rod extends out of the box and is connected with a heat-insulating shaft, a pressure sensor and a hydraulic cylinder; and a displacement measuring rod, which is in contact with a displacement sensor, is mounted on an extending part of the force transfer rod. The assessing test machine has the advantages that: the real working condition of the high polymer compound material is simulated and an assessing test for the tribological properties of the high polymer compound material is performed for detecting the abrasion loss and the change in frictional factor following the time of the high polymer compound material in real time.

The invention provides a method for measuring contents of multiple mono compounds containing different elements in a complex mixture through a one-dimensional nuclear magnetic resonance mixture jointly utilizing different nucleuses, and the application of the method. Even if characteristic signal peaks of various compounds in a mixture in a one-dimensional nuclear magnetic resonance graph of a certain specific nucleus are overlapped, the method can also rapidly and accurately measure absolute concentrations of multiple mono compounds in the mixture. One key factor of the method is taking a compound comprising one or more elements to serve as a universal quantitative internal stand of a nuclear magnetic graph of different nucleuses, and the internal standard plays a role of quantitative bridge in a one-dimensional nuclear magnetic resonance graph of different nucleuses. If the relative concentration ratio of certain compounds is only concerned, the result of the relative concentration ratio measured by the method is not related to the concentration of the internal standard, and is not influenced by weighing error.

The invention discloses a multifunctional laser photoacoustic detection method and device for elements, defects and residual stress, and belongs to the field of laser material detection. Pulse laser is incident to the surface of a sample to be detected by utilizing a pulse laser in order to generate plasma and ultrasonic waves, and the elemental composition, the structural defects and the residualstress of the sample can be simultaneously analyzed. The detection system comprises an excitation unit, a spectrum detection unit, an ultrasonic detection unit and an analysis control unit, wherein adigital delayer is connected to a computer; a high-precision 3D displacement platform is electrically connected to the digital delayer; the pulse laser emitted by the pulse laser is modulated, focused and incident to the surface of the sample to be detected through a light path system in order to generate the plasma and ultrasonic waves at the same time; the ultrasonic detection unit is used fordetecting the ultrasonic waves; and the spectrum detection unit is used for detecting a visible light spectrum emitted by plasma flame. According to the method and the device, simultaneous detection and analysis of the elemental composition, the defects and the residual stress of the sample can be realized.

The invention discloses a high-carbon steel wire rod austenite crystal grain size measuring method. The method comprises the following steps of: firstly, horizontally cutting a plurality of notches vertical to the length direction of a wire rod; then, heating the wire rod with the notches in a heating furnace so as to enable the wire rod to be austenitized completely, wherein the heating temperature is generally 860 DEG C-1300 DEG C; then, placing the heated wire rod rapidly into cold water for quenching treatment; and finally, breaking a quenched sample along the notches, photographing fractures cracking along crystals by a scanning electron microscope, observing the three-dimensional morphologies of crystal grains on the fractures directly by the scanning electron microscope, and measuring the sizes of the crystal grains. The method provided by the invention can be used for preparing samples simply, does not require corrosion, is high in success rate, and can accurately determine the sizes of the high-carbon steel wire rod austenite crystal grains.

The invention mainly belongs to the field of oil and gas exploration and development, and particularly relates to an oil-gas field on-site while-drilling cuttings scanning system and method. The oil-gas field on-site while-drilling cuttings scanning system comprises a sample preparation mould and a table-type mineral analysis scanning electron microscope; oil-gas field on-site while-drilling cuttings are prepared to a scanning sample through the sample preparation mould; the table-type mineral analysis scanning electron microscope comprises a secondary electronic probe, a backscattered electron probe, an energy spectrum probe and an electron microscope operation module; and the table-type mineral analysis scanning electron microscope is small in weight, small in land occupation, easy to carry and is suitable for the severe environment in a well field. According to an oil-gas field on-site while-drilling cuttings scanning method, the on-site while-drilling cuttings are fully utilized, mineral elements, mineral types and rock structures are rapidly analyzed, and lithology classification is quickly conducted; and the oil-gas field on-site while-drilling cuttings scanning method has the advantage of on-site real-time guidance drilling and oil-gas field exploration and development, limitation that a laboratory traditional mineral analysis electron microscope scanning system cannot be carried to the site for application is overcome, and the oil-gas field exploration precision and speed are improved.

The invention discloses a slurry consolidating apparatus and a use method thereof. The slurry consolidating apparatus comprises a power supply system, a sample production platform system and a die system. The method comprises the following steps: mixing fine grained soil with air-free water, pouring the obtained mixture into a container, sealing, storing, and stirring after water is fully absorbed; completing assembling of the die system; fixing the die system to a sample disposing base plate of the sample production platform; pouring a slurry into a sample die through a funnel; adjusting the height of a reaction force crossbeam to make a presser contact with the upper surface of the slurry; starting an inflator, and carrying out grading loading; allowing the sample to be in a sealed state; and applying an axial consolidating pressure, and respectively adding negative pressures with equal size to a top cover and a die pedestal to accelerate consolidation until consolidation is completed. The apparatus and the method effectively reduce the disturbance possibility of the sample, improve the repeatability of the sample, make the sample have uniform water content and particle size distribution, and effectively improve the sample production efficiency and the quality of the sample.

The invention discloses a preparation method of nano-silver-carrying PNIPAM / PVA composite thermosensitive gel. PNIPAM / PVA thermosensitive hydrogel prepared with a free radical polymerization method is used as a reducing medium, and silver nanoparticles are reduced in a network structure of the hydrogel; the finally prepared material is used as the substrate of SERS and soaked in crystal violet probe molecular solutions with different concentrations for a certain time; then the substrate material with probe molecules adsorbed on the surface is taken out, placed on a slide for airing and used for Raman detection. The hydrogel in the gel is used as a dispersion stabilizer and can play a role in support protection for electromagnetically enhanced nano-silver particles; when the gel is adopted as the substrate for detecting crystal violet at the room temperature, the detection limit can reach 10<-9> orders of magnitude, and the fact that the intensity of a Raman signal varies with temperature is also found. The disclosed SERS substrate adopts simple preparation method and is good in temperature response and has broad application prospect in fields of food additives, pesticide detection, sensing and the like.

The invention involves methods and uses of a combination of at least two nucleotide sequence identifiers in the preparation of a sample DNA for high throughput sequencing. Accordingly, in the high throughput sequencing a plurality of prepared sample DNAs, each preparation of a sample DNA comprises a unique combination of the at least two nucleotide sequence identifiers wherein a first nucleotide sequence identifier is selected from a group of nucleotide sequence identifiers and a second nucleotide sequence identifier is selected from the group of nucleotide sequence identifiers.

The invention discloses a microscopic imaging device and method for measuring microstructure defects on a surface of a semiconductor material. The testing device comprises a light source, a polarization modulation reflection difference system, a beam splitter prism, a scanning platform, a co-focusing microscopic system and a signal acquisition system. According to a photo-elastic effect principle and a crystal defect theory, although the microstructure defects on the surface of the semiconductor material have very small sizes, a very large strain distribution field relative to the microstructure defects is formed around the microstructure defects and the strain distribution field can generate an optical reflection anisotropic signal; the testing method can be used for measuring the optical reflection anisotropic signal of each measuring point around the microstructure defects so that an optical reflection anisotropic microscopic imaging pattern, which is close to the microstructure defects, related with the strain field and changed along with a space position, can be directly obtained, and furthermore, information including varieties, density, strain distribution and the like of the defects is obtained. With regard to characterization of the microstructure defects of the material, the microscopic imaging device and method, disclosed by the invention, have the advantages of simplicity and efficiency for operation, no damages, strong portability and the like.

The invention relates to a measuring method of Laves phase content of T / P 92 steel. The measuring method comprises the following steps: S1, sample preparation; S2, observing a sample under an SEM (Scanning Electron Microscope): optionally selecting at least five fields, respectively taking photos of a secondary electron (SE) and a back scattered electron (BSE) in a magnification time of 2500-5000; S3, identifying Laves phase particles: in the photo of the back scattered electron, compared with a M23C6 particle, the contract between the Laves phase and a matrix is higher, the luminance is larger, and determining the particle with a luminance different larger than 10% as the Laves phase; S4, image processing: carrying out binarization processing on the photos by image processing software Photoshop; S5, quantitative analysis of the image; and S6, statistical result processing. According to the measuring method of the Laves phase content of the T / P 92 steel provided by the invention, the sample preparation is simple, the operation is convenient, the range of viewing area is wide, the number of Laves phase particles of each field is large, and the distribution has statistical significance, so that the errors in subsequent quantitative results are small.

The invention provides a method and a device for measuring the continuous cooling phase transformation points of aluminum alloy. The method comprises the following steps of automatically collecting the data of resistance, temperature and time in real time by utilizing a computer, drawing a voltage-temperature curve or a resistance-temperature curve of an aluminum alloy sample according to the measured data, and then obtaining the cooling phase transformation points according to the drawn curve. The device comprises a heating insulation and cooling system, a dynamic voltage measuring system, a temperature measuring system, a signal amplifying and converting system and a data collecting and processing system which are sequentially connected. The device can be used for obtaining the curve of voltage changing along with the temperature in the continuous cooling process of a supersaturated solid solution, thereby judging the phase transformation points of the alloy. The invention has the advantages of wide cooling test range, high measuring precision, high speed and simple operation, and can carry out heating, insulation, cooling, and the voltage and temperature real-time measurement and collection on aluminum alloy materials.

An object of the present invention is to provide a medium; a specimen; a method for preparing the specimen; a method for observing the specimen; a sample cell; and an electron microscope capable of easily solving the problem of charge-up and further capable of observing a real shape or the like of a sample with a SEM, a TEM or the like. For the purpose of achieving the above-described object, the present invention uses an electrical conductivity-imparting liquid medium, for use in a microscope, which includes an ionic liquid as an essential component thereof and is impregnated into the entirety of a SEM or TEM sample or applied to the observation surface of a SEM or TEM sample to impart electrical conductivity at least to the observation surface of the sample. According to the present invention, the charge built up on the sample surface can be released simply by impregnating or coating the sample with the ionic liquid, and hence the problem of charge-up can be easily solved. Further, even when a sample impregnated or coated with the ionic liquid is placed under vacuum, the ionic liquid is not evaporated from the sample, and hence a biological sample can be observed as it is in an original shape.

This invention relates to CAP enzyme immunity test reagent box and ELISA competition method to test CAP. To use CAP and BSA coupler as the CAP antigen immunity small mouse, the monocolnal CAP antiserum with CAP antibody is obtained which is then put on the enzyme specimen board after separation, purification and dilution to be warm cultivated, washed and added with sample diluent and enzyme standard antigen to be reacted and washed to be added with enzyme substrate to display color with easy pretreatment especially for testing remained CAP of meat food stuffs.

The invention discloses an ultra-high-density single-walled carbon nanotube horizontal array and a controllable preparation method thereof. The method comprises the following steps: loading a catalyst on a single crystal growth substrate, annealing, introducing hydrogen in a chemical vapor deposition system, carrying out reduction reaction of the catalyst, maintaining introduction of hydrogen, and performing orientated growth of single-walled carbon nanotubes, thereby obtaining the horizontal array. The ultra-high-density single-walled carbon nanotube horizontal array prepared by the method has the density exceeding 130 nanotubes per micron and a single-walled carbon nanotube horizontal array with the highest direct growth density reported in the world at present. According to the test of electrical properties of the ultra-high-density single-walled carbon nanotube horizontal array prepared by the method, the horizontal array has the drain current density of 380 [mu]A / [mu]m and has the transconductance of 102.5 [mu]S / [mu]m, which are the highest level in carbon nanotube field effect transistors in the world at present.

The invention discloses a pearlite steel wire rod austenitic grain size measuring method. The method comprises the following steps that 1, a small block is cut out from a pearlite steel wire rod to serve as a sample, and the sample is ground, mechanically polished and electrochemically polished; 2, one face of the sample is used as an observation area, and an EBSD system is used for carrying out face scanning on the sample to obtain an orientation imaging figure; 3, a certain deflection angle difference is set, orientation analysis software of the EBSD system is used for carrying out statistics on the grain size, an average grain diameter is obtained, and the pearlite steel wire rod austenitic grain size is calculated according to the average grain diameter. According to the method, the pearlite steel wire rod austenitic grain size is rapidly and accurately measured through the EBSD technology, sample preparation is easy, the result can be quantitative, and the reproducibility is good.

The invention discloses a method for rapidly preparing a Ni-based superalloy electron backscatter diffraction (EBSD) sample. The method is characterized in that the electrolytic polishing is not required; and the sample is rapidly prepared by a chemical etching method. The method comprises the following steps of: cutting the sample by a wire cutting machine, pre-grinding the sample by using abrasive paper for metallograph, performing mechanical polishing, and etching the sample by using a chemical etchant. Kikuchi patterns of the Ni-based superalloy EBSD sample prepared by the method are clear. By the method, the disadvantages that a commonly used method for preparing an EBSD sample is complicated in electrolytic polishing sample preparation and has an unstable effect are overcome.

The invention discloses a sample containing device for a cone calorimeter and a method for measuring fused solid and liquid samples by using the same. The sample containing device comprises a containing cavity, side walls for enclosing the containing cavity and a bottom wall, wherein the cross section of the containing cavity is circular; the sample containing device is further provided with a movable baffle for shielding the containing cavity; the interiors of the side walls and / or the bottom wall form a cavity; the cavity is internally provided with a high-temperature-resisting heat-insulation filler layer; scales are arranged on one side of the containing cavity enclosed by the side walls. The sample containing device disclosed by the invention is especially suitable for determining powder and liquid samples by matching with the cone calorimeter; the structure guarantees that the samples can be heated uniformly in the detection process and the testing accuracy is improved; the sample containing device is easy to clean and is good in heat-insulation effect; the testing method does not need to use an aluminum foil so that the cost is saved and sample preparation is simplified; meanwhile, an error caused by combusting the aluminum foil in the testing process is reduced and the testing is accurate.

An embodiment of the invention provides a method, a device and a system for detecting heavy metals in soil and belongs to the field of soil detection. The method comprises steps as follows: under a preset detection condition, the device for detecting the heavy metals in the soil acquires the second characteristic X-ray spectrum of to-be-detected soil, and the second characteristic X-ray spectrum comprises the wavelength and the intensity corresponding to the heavy metals in the to-be-detected soil; the wavelength and the intensity in the second characteristic X-ray spectrum are compared with those in a first characteristic X-ray spectrum, and types of the heavy metals corresponding to the wavelength, identical to the wavelength in the second characteristic X-ray spectrum, in the first characteristic X-ray spectrumare used as types of the heavy metals in the to-be-detected soil; the intensities, corresponding to same types of heavy metals, in the first and second characteristic X-ray spectrums are compared, the content of the heavy metals in the to-be-detected soil is obtained according to the corresponding relation between the intensity and the known content of the heavy metals in the first characteristic X-ray spectrum, and the accuracy of soil heavy metal detection results is significantly improved.

The present invention relates to a process for the preparation of oligo(alkylene glycol)-functionalized polyisocyanopeptides comprising the steps of functionalizing an isocyanopeptide with oligo-(alkylene glycol) side chains and subsequently polymerizing the oligo-alkylene glycol-functionalized isocyanopeptides. Several isocyanopeptides may be functionalized with various linear or non-linear oligo-(alkylene glycol) side chains having variable chain length. The alkylene glycol may be selected from the group consisting of ethylene-, propylene-, butylene- or pentylene glycol. Preferably, the isocyanopeptides are functionalized with at least three ethylene glycol side chains. The peptides may comprise L-amino acids, D-amino acids or D, L-amino acids. The obtained oligoalkylene-functionalized polyisocyanopeptides are a new class of materials with unique thermo-responsive properties.

The invention relates to a high performance liquid chromatography assay method for formaldehyde and acetaldehyde in cigarette filter beads, and belongs to the technical field of tobacco inspection. The high performance liquid chromatography assay method for formaldehyde and acetaldehyde in the cigarette filter beads comprises the following steps: 1) putting ceramic protons and a cigarette filter bead into acetonitrile, performing vortex vibration to crush the cigarette filter bead, performing derivatization treatment, and filtering so as to obtain a liquid to be tested; and 2) testing the liquid to be tested by using high performance liquid chromatography. By adopting the high performance liquid chromatography assay method for formaldehyde and acetaldehyde in the cigarette filter beads, the sample pretreatment process is simple and rapid, the analysis time can be greatly shortened, and batch samples can be conveniently analyzed; the method is high in sensitivity and accuracy, good in repeatability and applicable to detection on residues of formaldehyde and acetaldehyde in the cigarette filter beads.

The invention discloses a method for determining 18 phthalic acid ester compounds in cigarette paper materials. The method comprises the steps of pretreating a cigarette paper material sample to prepare a sample solution, preparing a standard solution of 18 phthalic acid ester compounds, detecting and analyzing the sample solution and standard solution respectively by adopting liquid chromatography-tandem mass spectrum, and then quantitatively analyzing by adopting an external standard method to calculate the content of 18 phthalic acid ester compounds in the cigarette paper materials. The method has the advantages of being simple and fast to operate, simple for sample pretreatment, higher in sensitivity, high in detection speed, lower in detection limit, better in reproducibility, higher in recovery rate, stronger in anti-inference capability, more accurate in qualitativeness and the like. The determination method can cope with stricter cigarette security requirement, thus providing standardized guidance for the use of PAEs (phthalic acid esters) plasticizer in cigarette industry.

The invention discloses a method for detecting the dislocation density of ultra-low carbon steel with a Snoek relaxation internal friction peak method. By means of a Snoek relaxation internal friction peak, peak height and peak temperature of the Snoek relaxation internal friction peak are analyzed, so that the dislocation density of the ultra-low carbon steel is evaluated; with the adoption of the method for detecting the dislocation density of the ultra-low carbon steel, the detection sensitivity is high, the dislocation density of the ultra-low carbon steel can be accurately detected, and the method is particularly suitable for detecting the dislocation density of the ultra-low carbon steel in different deformation quantities; sample preparation and operation are simple, and the method has wide application prospect; with the application of Snoek relaxation internal friction peak for detection of the dislocation density, the sample preparation is simple, and the operation is also simple, easy and convenient.