217results about How to "Simplify the experimental process" patented technology

The invention relates to a visual simulation shale micro-crack plugging capacity test system and a visual simulation shale micro-crack plugging capacity test method. Displacement evaluation experiment is performed on a single or combined micro-crack rock sample by a solution or a drilling fluid which contains the plugging agents with different concentrations and different types at different experiment conditions, such as pressure differences and times, indexes, such as the invasion depth, are compared, the formation conditions of inner mud cakes in drilling are directly described, and microscopic observation and analysis are performed on percolation substances invade into the micro-cracks by utilizing amplification imaging instruments, such as a high-definition microscope, so that the plugging mechanisms and the effects of various drilling fluid plugging agents and drilling fluids are analyzed and researched intuitively and microscopically, a proper drilling fluid plugging agent is selected preferably, a drilling fluid system formula is optimized, the problem about the experimental conditions that the visual simulation evaluation cannot be performed on shale micro-crack plugging in the past is solved, and a new evaluation experimental research means is provided for related research and production in the technical field of fractured shale strata borehole wall stability in petroleum engineering.

The invention discloses a measuring method of high-temperature oil-water relative permeability of a heavy oil reservoir. A method for replacing high-temperature oil-water relative permeability of the heavy oil reservoir with oil-water relative permeability under the low-temperature oil-water system condition is put forward for the first time, reduces the measuring difficulty of the high-temperature oil-water permeability of the heavy oil reservoir, avoids potential safety hazards caused by high-temperature and high-pressure experiment conditions and simplifies experiment processes and operation requirements, and the oil-water relative permeability obtained with the two measuring methods is basically identical on the premise that the oil-water viscosity ratio is equal, thus, simple, time-saving, safe and accurate measurement of the high-temperature heavy oil relative permeability is realized with the method.

The invention belongs to the technical field of mass spectrometry and particularly relates to a cascade mass spectrometry method performed in an ion trap mass analyzer. The cascade mass spectrometry method performed in the ion trap mass analyzer specifically comprises three stages of ion selective segregation, collision induction dissociation and mass scanning and analyzing. According to the cascade mass spectrometry method performed in the ion trap mass analyzer, in the stage of collision induction dissociation, by changing the period of a radio frequency signal, namely changing the frequency of radio-frequency voltage loaded on an ion trap, parent ions with a certain mass-to-charge ratio undergo resonance excitation so as to obtain energy. The high-energy ions which undergo resonance excitation collide with neutral molecules in the ion trap and are dissociated, outcome ions are generated, and the cascade mass spectrometry is achieved. The cascade mass spectrometry method performed in the ion trap mass analyzer has the advantages that only arrangement of software can be used for changing the scanning period of the stage of collision induction dissociation in order to achieve collision induction dissociation, and thus, an experiment device and a method of cascade mass spectrometry can be obviously simplified.

The invention relates to an mRNA fragmentation method and a method for constructing a sequencing library based on the mRNA fragmentation method. The mRNA fragmentation method provided by the invention employs forward and reverse bridge-type probes, realizes breakage of an mRNA sample through one-step reverse transcription and connection reaction, and introduces two terminal linkers during reverse transcription so as to obtain a cDNA library with linkers at two terminals. The cDNA library with the linkers at the two terminals can directly undergo cyclization reaction or undergo PCR amplification before cyclization reaction, so a sequencing library for single-stranded cyclic nucleic acids can be obtained; or a sequencing library for single-stranded nucleic acids can be obtained by directly subjecting the cDNA library to amplification. When the mRNA fragmentation method is applied to construction of the sequencing library, tedious steps like restoration of a tail terminal and arrangement of a linker on one end at first and another linker on the other end next in traditional construction of libraries can be omitted; experimental flow is greatly simplified; a library construction period is shortened; and library construction cost is greatly reduced.

The invention discloses a preparation method of a silica shear thickening liquid. The preparation method comprises the following steps of: preparing monodisperse silica microspheres with certain grain size in an alcohol-water mixed liquid according to a multi-level seed growth method by utilizing tetraethoxysilane serves as a raw material and ammonia as a catalyst; after reaction is finished, adding shear thickening liquid dispersion media (polyethylene glycol, glycerol and the like) into a SiO2 suspension liquid; after mixing uniformly, removing ethanol, water and ammonia from the mixed liquid by adopting a heating and pressure-reducing method to finally prepare the silica shear thickening liquid, wherein the ethanol which is collected under reduced pressure can serve as a solvent and can be reused. In the preparation method, the SiO2 microspheres exist in the form of a uniformly dispersed suspension liquid from the synthesis link to the preparation link of the shear thickening liquid, so the agglomeration phenomenon of powder in drying and redispersion processes is avoided, and the stability and rheological property of the shear thickening liquid are improved.

The invention provides a primer set, a kit and a detection reaction system for detecting PKD1 gene mutation through the long fragment PCR and high-throughput sequencing technology, a non-diagnosis-purpose method for external PKD1 gene mutation detection, a non-diagnosis-purpose method for external PKD1 gene analysis and a method for detecting new mutation sites on the PKD1 gene. According to the method, the primer set is used for carrying out long fragment PCR amplification on the PKD1 gene of a sample, and detecting or analyzing is carried out through high-throughput sequencing. The autosomal dominant genetic polycystic nephrosis (adult polycystic nephrosis) can be diagnosed through the assistance of a detection result, previous unknown new mutation on a plurality of PKD1 real genes can be obtained and supplied to doctors or researchers so that the relevance between the mutation and the adult polycystic nephrosis can be studied.

The present invention discloses a DNA extraction method for polysaccharide plant dried leaves. The DNA extraction method comprises dried leaf grinding, desaccharifying, cracking, extraction, precipitation, washing, detection and other steps, wherein desaccharifying is the key step, a pre-heated desaccharifying buffer solution is added before the nuclear membrane is not cracked and the genome DNA is not released, the leaf tissue solution is suspended under a 65 DEG C water bath condition so as to dissolve polysaccharides and other secondary metabolites in the buffer solution, and low speed centrifugation is adopted to remove the polysaccharides and other impurities, such that the final DNA obtained through precipitation has high concentration and high purity. The DNA extraction method is suitable for dried mature leaves of all cerasus plants and other polysaccharide-rich plants, wherein the concentration of the obtained DNA can be increased if the leaves are the young and tender leaves, and the more DNA with high quality can be obtained from the mature leaves.

The invention relates to a physical simulation huff-puff production experimental method and device. The method is characterized by comprising the steps that 1, a core model for an experiment is vacuumized; 2, simulation formation water is sucked into the core model till the core model absorbs water to reach saturation; 3, crude oil is injected into the core model till no simulation formation water is drained out of the core model; 4, according to the solution gas-oil ratio data of a target oil field to be measured and core model output simulation formation water volume, the volume of gas needing to be injected into the core model is worked out; 5, the gas is injected into the core model; 6, huff-puff fluid is injected into the core model, the core model is closed, and a soaking process is simulated; 7, after experiment time is up, the core model is opened for huff-puff fluid and crude oil spurt, and one-time physical simulation huff-puff production experiment is completed. Experiments in different huff-pull ways can be carried out, influence effects of different injection parameters or parameter quantized comparison effect data, and a reliable evaluation platform is provided for thickened oil field exploitation in different huff-puff ways.

The invention discloses a method and a device for uniformly cladding metallic silver on the surface of a carbon nano tube. The method comprises the steps of preprocessing the carbon nano tube, preparing a silver-ammonia solution and a chemical plating solution, and adopting the device provided by the invention to carry out chemical plating, wherein the device comprises a vacuum pump, a collection bottle, a quartz tube, an ultrasonic atomizer, a microwave-assisted heater, a microwave leakage prevention device and a carrier gas conveyor device; carrying out ultrasonic atomization on the two solutions, contacting and mixing the two atomized matters to react, repetitively washing powder to be neutral, and drying to obtain the carbon nano tube with the surface uniformly cladded by the metallic silver. The carbon nano tube is dispersed in spray droplets, so that the dispersibility of the carbon nano tube and silver plating is improved, the phenomenon of self-decomposition of the solution in a conventional chemical plating method, the generation of large-particle monomer silver and the occurrence of silver mirror reaction are avoided, the prepared cladding layer is uniform, and the sliver particle size is nano-scaled; the whole process is simple, the device is simple and convenient, convenient to operate, and energy-saving and environmental-friendly, and mass production can be realized.

The invention discloses a construction method of a small-fragment DNA (deoxyribonucleic acid) library based on an Illumina Hiseq 2500 sequencing platform, which comprises the following steps: blood free DNA extraction, fragment size screening, terminal repair, 3' terminal linker addition, PCR (polymerase chain reaction) amplification, magnetic bead purification and the like. Compared with the library construction process based on a sequencing platform in the past, the method disclosed by the invention simplifies the experiment process, shortens the library construction time, optimizes the reaction system, greatly reduces the reagent consumption, lowers the library construction cost, lowers the library loss, and is suitable for constructing an artificially-fragmented small DNA library.

The invention provides a preparation method of a metal-doped zinc oxide liquid-phase homogenous-dispersed body. The preparation method is characterized in that zinc salt is used as a reaction source and metal salt is used as a doping source in an alcohol phase system, and on that basis, the metal-doped zinc oxide nano-particle dispersing liquid is prepared by adoptinga low-temperature solution method under an alkaline condition; then a trace of surfactant is added to further improve the dispersing stability and the conductivity. The liquid-phase homogenous-dispersed body is characterized in that the metal-doped zinc oxide particles are wrapped with the surfactant layer, and the one-dimensional size is 10-20nm; the nano-particles are uniformly dispersed in the liquid-phase medium; the concentration of the metal-doped zinc oxide particles in the dispersed body is 10-20mg / mL. The preparation temperature of the metal-doped zinc oxide dispersed body is not beyond 80 DEG C; the preparation process is simple, the energy is saved and the environment is protected; the product is high in stability, high in conductivity, and free from precipitation after standing for more than 3 months; the obtained nanometer material is high in conductivity and has a good application prospect in the field of photoelectric appliance such as the solar cell field.

The invention relates to a genetyping method based on SNP site nucleic acid mass spectrum detection and application thereof. The genetyping method comprises: (1) designing a specific primer with respect to sequence SNP site of a target gene; (2) amplifying a target segment containing the specific SNP site of the target gene utilizing single-pipe multi-PCR; (3) digesting PCR product segment utilizing restriction enzyme; (4) performing single basic group extension reaction; (5) desalting and purifying; and (6) detecting and analyzing the gene sequence of the specific SNP site of the target gene.The genetyping method based on SNP site nucleic acid mass spectrum detection is high in detection accuracy, high in experiment repetition, large in flux, and low in cost. The invention also disclosesapplication of the genetyping method based on SNP site nucleic acid mass spectrum detection in single nucleotide polymorphism. The method can specifically and simply type the target gene or pathogenic microorganism, thereby greatly improving the typing efficiency.

The invention discloses a motor and hydraulic pressure combined drive in-situ test device for the structure properties of materials, and belongs to the technical field of material structure performance in-situ detection. The device comprises an outer frame, left-handed and right-handed ball screws, a moving base A, a moving base B, a sample chuck, a motor drive system and a hydraulic drive system. The device has good experimental equipment compatibility; servo motor and hydraulic pressure dual drive is adopted, tension or pressure force is large, and the strength range of the experimental materials is expanded; the moving distance of the sample chuck is long, and large deformation can be achieved; displacement and force detection precision is high; the deformation rate can be controlled, and displacement or force closed-loop control can be achieved. The device can be used independently or used in cooperation with X-ray diffraction equipment, the problem that only end state detection can be conducted in existing experiments is well solved, and material structure changes in a transient state and material structure changes at special strain points in tension and compression of the sample can be observed in situ.

The invention relates to a fusion protein used for single-cell ChIP-seq library preparation and application thereof. The fusion protein comprises Tn5 transposase and an Fc binding protein; a kit comprises the fusion protein and other auxiliary detection reagents; a method uses the fusion protein or the kit for ChIP-seq detection. The fusion protein, the kit and the method can improve the library building efficiency and lower the library background in the ChIP-seq detection process, so that the accuracy of the ChIP-seq detection method can be improved, and the experimental flow of ChIP-seq canbe simplified.

The invention provides a halamine double bond hydantoin antiseptic, and a preparation method and an application thereof. The preparation method comprises the following steps: adding equimolar NaOH and 5,5-dimethylhydantoin into a flask, adding deionized water, stirring until colorlessness and transparency, adding equimolar 3-chloro-1-propanol, heating to 100DEG C, and reacting under condensation refluxing conditions for 10-15h; putting the above obtained substance in a flask, adding a solvent tetrahydrofuran, adding equimolar triethylamine as an acid scavenger, adding equimolar acryloyl chloride under ice bath conditions in a dropwise manner, and reacting for 1h; and reacting at room temperature for 20-24h to obtain 3-(3-propyl acrylate)-5,5-dimethylhydantoin. The method has the advantages of simplicity, high efficiency, no use of an initiator or a cross-linking agent, mild technologic conditions, no need of a high temperature, energy saving, reduction of pollution of industrial waste liquids through using energy of high energy electron beams to initiate, substantial sterilization effect and good application prospect.

The invention discloses a permeating rate and porosity testing device for rock type materials. The device comprises a pneumatic pressurizing system, a flowmeter, an upstream pressure chamber, a rock core clamping device, a downstream pressure chamber, a soap-foam flowmeter, a hydraulic system, a valve K1 used as an unsteady state control valve, a valve K2 and a valve K3, wherein the valve K2 and the valve K3 are used as steady state control valves. According to the device, the steady state permeating rate testing and the unsteady state permeating rate testing are integrated, so that the process is greatly simplified on the basis of traditional cutting, and as a result, the cost is greatly reduced.

The invention relates to the field of biotechnology, and provides improved identification for target RNA sequences bound to RNA-binding protein in cells. Through UV crosslinking-immunopricipitation, target RNA of RNA-binding protein is obtained, micrococcal nuclease is adopted for carrying out incomplete enzymolysis on the target RNA after ultraviolet crosslinking, after enzymolysis, a chelating agent capable of removing Ca<2+> is adopted for inactivating the enzyme, the 3' terminal of the target RNA obtained through the method is phosphorylated, the phosphorylated 3' terminal is ligated witha 3' RNA linker, then, the ligation product is phosphorylated, the phosphorylated ligation product is separated, the separated phosphorylated ligation product is recycled, then the 3' terminal is ligated with a 5' RNA linker, RT-PCR amplification is carried out, so that a cDNA library corresponding to the target RNA is obtained. With the technical scheme provided by the invention, the experiment flow is simplified, the step of isotope labelling is eliminated, due to the adding of an IgG antibody negative control sample, the influences of non-specific binding and background on the experimentalresult are eliminated, and the data result with the quality equal to that of Clip-seq is obtained.

The invention relates to a preparation method of a TiAl-based alloy with a fine fully lamellar microstructure, which belongs to the technical field of preparation of titanium alloys. The preparation method comprises the following steps: placing a powder metallurgic TiAl-based alloy at a temperature which is 5 DEG C-15 DEG C higher than the alpha-phase beta-phase transformation temperature Talpha; and preserving the heat for 15-25 minutes under a protective environment, and cooling to obtain the TiAl-based alloy with the fine fully lamellar microstructure, wherein the powder metallurgic TiAl-based alloy matrix structure is a nearly gamma structure or a gamma structure. According to the preparation method of the TiAl-based alloy with the fine fully lamellar microstructure disclosed by the invention, the fully lamellar microstructure with eutectic cell dimension of 150 microns-320 microns and lamellar spacing of 0.2 micron-0.4 micron can be obtained by a simple thermal treatment method. Moreover, the preparation method is free of hot mechanical treatment, simple in process and low in cost, so that not only can structure optimization be carried out before alloy forming, but also treatment can be directly carried out onto a formed piece. Besides, the preparation method has the advantages of being capable of controlling the microscopic structure of the alloy, simple in production process, regular in used equipment, low in production cost and the like, and is convenient for industrial production.

The invention discloses a current and surface pressure adjustable cable buffer layer ablation fault simulation device and method. The device comprises a power frequency voltage loop unit used for providing voltage applied to a buffer layer and a buffer layer ablation experiment unit connected to the power frequency voltage loop unit. The buffer layer ablation experiment unit comprises a sealed cavity, a fixing and clamping assembly arranged in the sealed cavity and used for fixing and clamping a buffer layer, an electrode assembly used for applying current to the buffer layer, a pressure adjusting piece used for applying surface pressure to the buffer layer and a self-weight adjusting assembly. By adjusting the amplitude of the externally applied voltage and the mass of the voltage regulating part, the ablation working condition simulation of the buffer layer under different currents and surface pressures is realized, the ablation characteristics of the buffer layer under the influenceof different current amplitudes and surface pressures are further researched, and a reliable experimental platform can be provided for the fault simulation analysis of the buffer layer of the high-voltage cable.

The invention provides a group of flavivirus-detecting gene chip probes and a general detection method. The probes include a Tick borne encephalitis probe, a Denguo virus probe and a Japanese encephalitis probe. A general primer sequence of flaviviruses capable of specific reverse transcription is designed, and flavivirus specific primers are utilized to perform reverse transcription for guiding the synthesis of viral genome so as to reduce interference in host cell gene components to the fullest extent and improve the specificity and accuracy of detection results. The invention can be used for the gene amplification of all flaviviruses and the gene chip detection of Tick borne encephalitis, Denguo virus and Japanese encephalitis.

The invention provides a photovoltaic member heat-transfer coefficient testing device and a method thereof. The testing device comprises an indoor case, an outdoor case, a test piece frame, a filling plate, an electrothermal membrane member, a wind-separating board, a blower fan, a first evaporator, a second evaporator, a first electric heater, a second electric heater, plural temperature sensors, an environment space case, an air conditioner, a first humidity-control apparatus, a second humidity-control apparatus, an electrothermal membrane power supply, and a control and data acquisition system. The electrothermal membrane member comprises an electrothermal membrane, a panel and a backboard, the upper and lower surfaces of the electrothermal membrane are adhered with the panel and the backboard by an EVA adhesive layer; the plural temperature sensors are uniformly distributed on the electrothermal membrane, and the thermocouples are connected with the control and data acquisition system. The device and the method overcome the disadvantage that the current technology cannot test the heat-transfer coefficient under photoreceptive power generation state, and can provide reference for testing heat-transfer coefficient of an inner heat source building enclosing structure.

The invention discloses a kit for aptamer screening. The kit comprises the following raw materials: a magnet, streptavidin-modified magnetic beads, a nucleic acid library, a short sequence, a PCR liquid premix, ePCR micro-droplet generation oil, a fluorescence quantitative PCR liquid premix and a molecular weight standard sample. The invention also discloses a using method of the kit for aptamer screening. The method comprises the following steps: S1, immobilizing the nucleic acid library on the magnetic beads; S2, performing screening; S3, performing PCR amplification; S4, preparing ssDNA; and S5, performing multi-round screening. The invention also discloses a method for detecting the binding rate of aptamer screened by a magnetic bead method and a target. According to the invention, thescreening period is shortened, the screening time is saved, the experimental flow is simplified, the repeatability is good, and the screening efficiency is high.

The invention discloses a porous foam enhanced metal composite material and a preparation method thereof and belongs to the technical field of composite materials. The preparation method comprises thefollowing steps: first, carrying out chemical silvering and preparing a reducer solution; preparing a carbon-containing nanotube electroplating solution taking copper sulfate pentahydrate as main salt; carrying out chemical silvering and electrocoppering (a carbon-containing nanotube) on melamine foam; then carrying out thermal treatment to obtain foam metal carbon-serial copper; filling copper power; tabletting the mixture by a tabletting machine to prepare flakes; and sintering the flakes by an SPS sintering furnace to obtain a final composite material. By taking copper-carbon-serial foam as a framework, the composite material is prepared by means of a copper power filling method. The carbon nanotube is free of large area agglomeration inside, so that the mechanical property of the finally obtained composite material is improved greatly. The composite material has a wider application field. The porous foam enhanced metal composite material is simple in integral process, and used devices are concise and convenient to operate, so that mass production can be achieved.

The invention discloses establishment and application of a novel HIV-1 drug resistance detection method. The novel HIV-1 drug resistance detection method established according to the invention has theadvantages that 1, by utilizing multiple sets of primer combinations, a problem of low amplification efficiency of target genes, which is caused by differences of different subtypes of strain sequences, is considered; and 2, synthesis of PR, RT and IN target gene cDNA and first-round amplification of a target gene nested PCR are completed in one reaction tube so as to avoid respective amplification on the target genes, simplify the experimental process and save reagent cost by 50%. The detection method established according to the invention can simultaneously cover multiple strain subtypes, and simultaneously cover multiple gene regions, which enables HIV-1 drug resistance detection efficiency to be greatly improved, and has the great influence on aids prevention and public health.

The invention discloses a method for culturing adult mouse cardiac fibroblasts. The method comprises the following steps: taking SPF grade 8-12 weeks-old mice, and sterilizing the material after cervical dislocation; taking out the heart of the mice and placing the mice in a culture dish containing pre-cooled calcium-free HBSS, extruding the residual blood in the heart, removing the heart atrium,left and right auricula, and pericardium, preserving the ventricle, transferring the material to a new culture dish containing the pre-cooled calcium-free HBSS, cutting the heart, transferring the material to a centrifuge tube, and after the cardiac tissue is precipitated, sucking the HBSS by a pipette; adding a collagenase digestion solution in the centrifuge tube for digestion, and then resuspending the material to obtain a cell suspension; spreading the material into a first culture dish and performing standing culture; resuspending the cells, discarding a supernatant by centrifugation, spreading the resuspended cells in the medium to a second culture dish, and adding the original first culture dish to the new medium. The culture method is simple and easy, has good stability, high repeatability and uniform morphology, and the obtained fibroblasts grow well.

The invention discloses a thin-wall pipe material heat conductivity coefficient calculating method adopting a transient heat transfer calculation model and belongs to the field of solid-material thermophysical property measurement. The thin-wall pipe material heat conductivity coefficient calculating method includes: putting forward a new thin-wall pipe heat conductivity coefficient calculating model-a Hot Spring model and giving out a concrete formula; measuring to-be-measured temperature points in the model by applying a temperature sensor, and performing fitting on response data of the measured temperature time to acquire a time parameter sigma; determining the formula of the final Hot Spring model and calculating out heat conductivity coefficient of a thin-wall pipe material according to the slope of the formula. Compared with the prior art, the thin-wall pipe material heat conductivity coefficient calculating method has the advantages that reprocessing of the to-be-measured sample is not needed, experiment procedure is simplified, and precision in measuring the heat conductivity coefficient of the to-be-measured sample of the kind is improved.

The invention relates to an Fe-Mn-Ni-Cr four-component high-entropy alloy. The alloy expression of the Fe-Mn-Ni-Cr four-component high-entropy alloy is FeaMnbNicCrd, wherein a, b, c and d of the alloyexpression represent the atomic percentage of corresponding components and meet the following conditions: a 38-57, b 18-37, c 8-15, and d 10-17; and a+b+c+d=100. The Fe-Mn-Ni-Cr four-component high-entropy alloy provided by the invention has a series of advantages of high strength, good plasticity, corrosion resistance and the like, and is simple in preparation process and low in production cost.

The invention relates to fusion protein, a kit and a CHIP-seq detection method. The fusion protein comprises Tn5 transposase and Fc binding protein, the kit comprises the fusion protein and other auxiliary detection reagents, and the method is the CHIP-seq detection method by using the fusion protein or the kit. According to the fusion protein, the kit and the method, the library establishment efficiency can be improved in the CHIP-seq detection process, the library background is reduced, the accuracy of the CHIP-seq detection method is improved accordingly, and the experimental process of CHIP-seq is simplified.

The invention discloses a preparation method of poly(N-isopropyl acrylamide) / graphene composite materials with photo-thermal responsiveness. The method comprises steps of firstly, adding the poly(N-isopropyl acrylamide) into graphene dispersion liquid; then, adding eight glycidol-based polyhedron polysilsesquioxane and 2-ethyl-4-methylimidazole; carrying out uniform stirring and dispersion, acquiring electricity texture liquid; through an electrostatic spinning method, obtaining a spinning thin film containing poly(N-isopropyl acrylamide) / graphene; and after crosslinking, obtaining composite materials with the photo-thermal responsiveness. According to the invention, based on the electrostatic spinning method, materials are prepared; the material ratio is easy to modulate and control; thematerials are easy to prepare; the obtained materials have advantages of high response speed and obvious response feature change and favorable application prospects.

The invention relates to a DNA pulldown method and a kit. The method includes the following steps of pretreating magnetic beads, wherein the magnetic beads marked by BSA(bovine serum albumin) and oligonucleotide random primer closed streptavidin are used; preparing a probe-magnetic bead compound; extracting and pretreating cell nucleus protein, wherein deoxyribonuclease is added into an extracting nucleoprotein sample for incubation, the magnetic beads are added for incubation and then removed, and supernatant is collected; carrying out pulldown; collecting the protein sample. The DNA pulldown method has the following advantages that BSA and an oligonucleotide random primer are used for closing the magnetic beads in advance, and nonspecific binding between the magnetic beads, protein and genomic DNA is reduced. Nuclease contamination is prevented through systemic nuclease protection, stability and reliability of experiments are improved, repeatability is high, and the experiment process is simplified.