53results about How to "Reduce the risk of harm" patented technology

The invention discloses a special saline and alkaline land organic / inorganic compounded fertilizer as well as a preparation method and application thereof. The compounded fertilizer comprises raw materials, namely a mixture 1 and a mixture 2, wherein the weight ratio of the mixture 1 to the mixture 2 is (1.5-3.5):1; the mixture 1 comprises composite charcoal, a biological organic fertilizer, humicacid substances, furfural residues, an improvement preparation and inorganic nutrients which are mixed according to a certain ratio; the mixture 2 comprises a biological organic fertilizer, humic acid substances, furfural residues and water retention aids which are mixed according to a certain ratio. By adopting the product disclosed by the invention, soil structures can be improved, soil porosity can be improved, soil bulk density can be reduced, contents of organic matters in soil can be increased, the cation exchange amount of the soil can be increased, and the pH value of the soil and thetotal amount of water soluble salts in the soil can be reduced. In addition, the fertilizer has functions of slowly releasing acid substances and nutrients, is capable of activating soil, reducing immobilization of soil upon nutrients and increasing the utilization rate of the nutrients, is capable of continuously and stably improving soil, is free of adverse influence upon environments and plants, and is ecological and environmentally friendly.

The invention discloses a prevention and control method for debris flow induced by ice-lake break and an application of the method. The method comprises the steps of determining a flood peak flow threshold of break flood debris flow in combination with topographic and geomorphic characteristic parameters of a drainage basin, rainfall characteristic parameters, inner-source characteristic parameters of the drainage basin, transport capacity of a main river and the like; then judging the stability of a morainic dam body in each calculation area and performing classification of dangerousness based on basic parameters obtained by field investigation, sampling and indoor testing of the morainic dam body; and based on this, determining body shape parameters and a distribution mode of pile structure bodies in the morainic dam body. According to the method and the application, for the situation that sudden ice-lake break caused by buried ice melting in the morainic dam, ice landslides and entry of ice into a lake due to icefall easily forms a giant debris flow disaster, the dam body undercutting speed can be effectively controlled, the break flood discharge time can be prolonged, the peak flow of break flood can be reduced, and the scale of forming the debris flow by the break flood can be reduced, regulated and controlled, so that the risk of causing harm to a downstream zone of the ice lake by the break flood is lowered.

The invention discloses a soil arsenic and chromium pollution repairing agent based on an organoclay-loaded nano iron series. The repairing agent is prepared by mixing 55-85% of organic montmorillonite-loaded nano zero-valent iron and 15-45% of organic montmorillonite-loaded nano iron oxide by weight, wherein the organic montmorillonite-loaded nano zero-valent iron is obtained by reduction of nanozero-valent iron on iron-based montmorillonite particles and then organic modification; the organic montmorillonite-loaded nano iron oxide is obtained through organic modification of iron-based montmorillonite and then oxidation into nano iron oxide.

The invention discloses a heavy metal combined pollution soil remediation agent based on modified clay and a preparation method of the agent. The agent comprises 10-15wt% of a component A, 30-65wt% of a component B and 25-60wt% of a component C. The agent is a multi-component modified bentonite universal compound remediation agent used for treating multi-heavy-metal combined pollution soil; bentonite is adopted as a template of the agent, the different modified bentonite components can be prepared according to different modification methods, and then the component proportion of the agent can be adjusted according to the different types and contents of heavy metals in the soil; the component A contains sodium-based large-diameter bentonite particles which aim at heavy metal pollutants of relatively wide types; the component B contains inorganic pillar bearing modified bentonite particles which have an relatively good effect on stabilizing cationic heavy metal pollutants; the component C is organic modified bentonite particles which have a relatively good effect on stabilizing anionic heavy metal pollutants. Accordingly, the remediation effect on complex heavy metal pollution soil of the agent can be improved by adjusting the proportions of the three components.

The invention discloses a method for preparing multi-component organically-modified bentonite-embedded nanoscale zero-valent iron. The method comprises the following steps that (1) bentonite is preprocessed; (2) 20-50 g / L of bentonite particles are added to 0.1 M of a FeCl3 solution, the bentonite particles and the solution are fully mixed and centrifuged, supernatant liquor is removed, and the process is repeated twice, so that Fe3+ saturated bentonite particles are obtained; (3) the Fe3+ saturated bentonite particles are added to deionized water, the pH is regulated to range from 2 to 3.5, NaBH4 is added to the mixture according to the molar ratio, 25-35:1, of the NaBH4 to Fe3+ under the protection of inert gas, the mixture reacts for 1-3 min at room temperature, and then bentonite-embedded zero-valent iron is obtained through high-speed centrifugation; (4) three organic cation modifying agents, namely HDTMA, TPMA and TMA are added to the deionized water mixed with the bentonite-embedded zero-valent iron, a replacement reaction is conducted for 15-30 min in an oxygen-free environment, and then the multi-component organically-modified bentonite-embedded nanoscale zero-valent iron is obtained through high-speed centrifugation. By means of the method, the clustering phenomenon of nanoscale iron in a complex heavy nonaqueous-phase environment can be relieved, and the surface hydrophobic performance is improved; through organic modification of the three components, adsorption of the bentonite and the reducing action of iron, the environmental behavior and the form of the nanoscale iron are improved, and the degradation efficiency of the nanoscale iron is improved finally.

The invention discloses a closed circulating heating thermal phosphorization device and a phosphorization method, relating to the technical field of drilling tool thread phosphorization. The device comprises a fluid heater, a phosphorization pool, a heating controller, a spray head, a circulation pipeline, a rubber check ring and a rubber stopper, wherein the fluid heater and the phosphorization pool are connected through the circulation pipeline; the spray head is fixed above the phosphorization pool; a water outlet of the circulation pipeline is connected with the spray head; a drilling rod is supported by a pipe rack and arranged above the phosphorization pool; the rubber stopper is arranged in a water hole of the drilling rod; the rubber check ring is sleeved on a drilling rod joint, and the inner wall of the rubber check ring is in close contact with the outer wall of the spray head; threads extend into a cavity formed by the spray head and the rubber check ring; and the heating controller is connected with the fluid heater. The invention can control the temperature, the pressure and the flow to carry out semi-soaking type phosphorization on the threads so as to solve the technical problems of difficult temperature constancy and non-uniform medicine liquid spraying in thermal phosphorization.

The invention provides a method for killing tumor cells through combination of a gold-mediated near-infrared light heat effect and an autophagy inhibitor. Compared with the prior art, the use quantity of gold nanoparticles can be reduced due to introduction of the autophagy inhibitor, and a god tumor cell killing effect can be obtained by a low dose of laser, so that the injury risk of laser and gold nanoparticles on normal cell tissue is reduced.

The invention discloses a porket creep feed without fish meal, comprising the following nutrient components in parts by weight: 680-690 parts of porket basic feeds, 80-100 parts of expanded soybean, 30-50 parts of low protein whey powder, 20-40 parts of dried porcine soluble, 20-40 parts of plasma protein powder, 15-25 parts of soybean oil, 4-5 parts of lysine, 1.5-2.5 parts of threonine, 0.5-1.5 parts of methionine, 25-35 parts of white sugar, 15-18 parts of calcium hydrophosphate, 15-20 parts of limestone powder, 2.0-2.5 parts of zinc oxide and 15-25 parts of premix compounds. The invention also discloses a preparation method of the porket creep feed. The porket creep feed provides proteins, energy, minerals, vitamins and nutritional growth promoting agents for the porkets and meets the requirement for protein nutrition needed by growth of the porkets. Without fish meal with higher production cost, the porket creep feed reduces the cost and simultaneously reduces the risks in the existing fish meal.

The invention belongs to the field of aeroengine mechanical systems, and discloses a lubricating oil return filter with a one-way valve. The lubricating oil return filter with the one-way valve is formed by a joint, a one-way valve assembly, a valve seat, an adapter seat, a filter element, a shell, a mouthpiece, an end cover and a spring. An integrated matching form of the one-way valve assembly and the oil filter is adopted, when lubricating oil pressure exceeds a spring force, the valve is opened, and when no lubricating oil pressure exists or the pressure is insufficient to counteract the spring force, the valve is closed, so that the purpose of one-way working of the valve is achieved, and reverse lubricating oil is prevented from entering aircraft accessories; and through the oil filter, lubricating oil generated after aircraft accessories work can directly return to an engine lubricating oil tank after being filtered, the structure is simplified, the weight is reduced, and reliability is improved. When the valve seat is designed, a semicircular polishing limiting structure is adopted to be in contact sealing with rubber on the one-way valve assembly, so that the damage probability of the rubber is reduced, and the service life is greatly prolonged; and the design of maximizing the flow area of the lubricating oil is adopted, so that the flow resistance is reduced, and thehazard risk caused by unsmooth oil return in the aircraft accessories is reduced.

The invention relates to the technical field of polyester filaments, in particular to a preparation method of cationic dyeable polyester filaments. The preparation method comprises the following steps: firstly, adding ethylene glycol and an anti-ether agent to a reactor for stirring, and adding isophthalic acid-5-sodium benzene sulfonate after heating for a direct esterification reaction, judgingthe reaction endpoint on the basis of yield of esterified water, and adding ethylene glycol and sodium acetate trihydrate after the reaction for blending to prepare a solution of SIPE (sodium 5-sulfodimethyl isophthalate), namely, a modified monomer solution; adding the solution of modified monomers to an oligomer, performing pre-polycondensation and final polycondensation reaction to obtain modified polyester melt, and preparing the cationic dyeable polyester filaments with a spinning process. The preparation method has short flow and few procedures, cannot produce toxic, flammable and explosive methanol in the process of preparing the modified monomer solution, and is environmentally friendly; besides, no heavy metal catalyst is used in the reaction process, so that the cost is saved, and the risk of harm to the environment and human body is reduced.

The invention relates to the technical field of fruit tree seedling culturing and planting, and in particular relates to a method for culturing and planting seedlings of American wild peaches. The method comprises the following steps: culturing seedlings, constructing an orchard, planting, performing disease and pest control, and performing topdressing. By adopting the method for culturing and planting seedlings of American wild peaches, a scientific and reasonable seedling culturing and planting method is adopted, so that peach trees are high in survival rate and small in disease and pest, and the peaches can be completely full and moderate in acidity and sweetness.

The invention discloses an acetamiprid / cyhalothrin-containing insecticidal composition and application thereof. According to the composition, acetamiprid and cyhalothrin are used as active components, and a foliage fertilizer is used as a synergistic assistant. The insecticidal composition has obvious synergistic actions, and effectively displays the advantages of the acetamiprid, cyhalothrin and foliage fertilizer. The obtained product has the advantages of excellent quality and favorable drug effect, obviously lowers the dosage and use frequency of drugs, saves the economic cost, reduces the residue level of the drugs in the agricultural product and environment, prolongs the drug resistance of pests and the service life of the drugs, can enhance the yield and quality of the crops, and has important economic, environmental-protection and ecological meanings.

The invention discloses a gluconobacter gene traceless operation system and application. The gene traceless knockout system comprises a strain of wild gluconobacter and a recombined integrated suicide plasmid with SacB genes, antibiotic marks and multiple cloning sites. A method for knocking out genes in the gluconobacter through the gene traceless knockout system includes the steps that 1, the multiple cloning sites of the recombined integrated suicide plasmid are led into upstream and downstream segments of target genes to be knocked out, and a suicide knockout plasmid is obtained; 2, the obtained suicide knockout plasmid is transformed into the wild gluconobacter, antibiotic resistance screening and sucrose screening are sequentially performed, and gene defect strains with the target genes to be knocked out are obtained through colony PCR verification. The SacB genes are adopted as screening marks, gene traceless operation is performed on the gluconobacter, and the system is an improvement on a system with upp genes adopted as screening marks; in addition, no operation needs to be performed on host bacteria, the wild gluconobacter can be adopted, and the system is wide in application range and safe in operation.

The invention provides an agricultural production source tracing system. A monitoring system and acquisition equipment acquire basic data and transmit the basic data to a geographic information system. The geographic information system performs integrated display of the space and attribute data for the basic data, and the geographic information system transmits the space and attribute data to a planting area satellite image and an information processing system. The geographic information system transmits feedback data to a product source tracing and coding system. The product source tracing and coding system transmits a source tracing code to a central server. The central server transmits the source tracing information to a source tracing website, and the central server outputs a source tracing two-dimensional code. The advantages are that "farm-to-table" whole process traceability information management can be realized, and the consumer is enabled to more accurately know the information of the whole process including production, processing, logistics, warehousing and sales through the source tracing link and enabled to select the assured product.

The invention relates to self-luminous anticorrosive paint for steel structures in traffic engineering and a preparation method of the self-luminous anticorrosive paint. The self-luminous anticorrosive paint is prepared from epoxy resin, a diluting agent, graphene, glass flakes, nano silicon dioxide, zinc powder, filler, a self-luminous material, an antifoaming agent, a dispersing agent, a leveling agent and a curing agent. On the premise that the content of zinc powder in the paint is sharply reduced, problems of poor coating compactness, large quantity of defects such as holes, poor aging resistance, adhesive force and impact resistance, proneness to cracking and peeling and the like of existing conventional surface paint for the steel structures in traffic engineering, energy accumulating and self-luminous performances are achieved, and accordingly special functions including traffic sign warning, traffic flow induction and the like of traffic steel structures such as bridge bodies,guard rails and cable ropes in nighttime and extreme severe environments can be realized while attractiveness of bridges and roads is achieved, and the paint is integrally excellent in technical performance, cost performance and environmental friendliness.

The invention relates to the technical field of environmental engineering, in particular to an in-situ remediation method for heavy metal cadmium moderate pollution of a farmland, the in-situ remediation method comprises the following steps: 1) a soil remediation agent and an organic fertilizer a are added into a 0-20 cm soil layer of cadmium polluted paddy land tillage planting soil; 2) an organic fertilizer b and calcium oxide are added into 20-40 cm soil layer soil which is not polluted, and the pH value is adjusted to be 6.5-7.5; 3) the 20-40 cm soil layer soil with the organic fertilizeradded is overturned to the 0-20 cm surface layer soil; 4) and the purpose of remediation of the cadmium-polluted soil is achieved by remediation for 90-150 days. The soil remediation method is wide inapplication range and short in repair period, the risk of residual heavy metals on the environment can be blocked, and the remediation agent is complexed and chelated with pollutants, and in particular, powdered rock phosphate in the remediation agent can enable the cadmium in the polluted soil to be converted from a high activity exchange state to a low activity acid solution state and residue state, so that the biological effectiveness and the migration capacity of the cadmium can be effectively reduced.

The invention discloses a method for immobilizing heavy metal in a lawn compost matrix with graphene. According to the method, graphene or a derivative thereof is selected as an adsorbent, large-size graphene nanoplatelets or multilayer graphene oxide is selected for immobilizing heavy metal in a lawn household refuse compost matrix, a scientific basis can be provided for immobilization of compost heavy metal, and recycling of household refuse can be promoted. The invention further discloses application of the method for immobilizing heavy metal in a lawn compost matrix with graphene in improving adsorption on heavy metal Cd, Cr, Cu, Pb and Zn in a lawn household refuse compost matrix system.

The invention discloses an intelligent alarm method and system. The intelligent alarm method comprises the following steps of acquiring sensor data and a sensor module identifier from at least one sensor module; looking up a sensor module table by using the sensor module identifier, and acquiring an abnormal table of the sensor module; looking up the abnormal table by using the sensor data, and judging whether the sensor data exceeds a threshold; and giving alarm information when the sensor data exceeds the threshold. According to the method and system provided by the invention, the automaticintelligent alarm can be performed according to the information collected by the sensor, and the risk of being harmful to the user due to negligence is greatly reduced.

The invention discloses a method for determining the transfer rate of an isothiazolinone preservative in a wet wipe during simulated use. The method is characterized in that the contents of isothiazolinone in a wet wipe before and after simulated use are detected, and the transfer rate of the isothiazolinone preservative in the wet wipe during the simulated use is calculated so as to reflect the transfer condition of the isothiazolinone along with the liquid during the use of the wet wipe, ie., the possible retention degree of the isothiazolinone on the skin; and the standard wet wipe sample simultaneously containing five kinds of isothiazolinones is prepared, and the samples with the high standard level, the medium standard level and the low standard level are subjected to detection analysis and summarization induction. According to the present invention, with the application of the method to detect the transfer rate of the isothiazolinone preservative in the actual wet wipe during the simulated use, the detection result is consistent with the standard wet wipe sample; and the method has characteristics of accurate quantitation and good reproducibility, and can provide the technical support for the quality and safety supervision of daily necessities.

The invention discloses a computer network information safety device for teaching, which comprises a cabinet body, supporting legs and a first shielding drawer, the lower surface of the cabinet body is fixedly connected with the supporting legs, the upper end of the front surface of the cabinet body is movably connected with the first shielding drawer, and the middle part of the front surface of the cabinet body is movably connected with a second shielding drawer. The lower end of the front surface of the cabinet body is provided with a shielding door, and one end of the shielding door is movably connected with a fixed handle. Through cooperative arrangement of the first shielding drawer and the second shielding drawer, mobile communication equipment or mobile storage equipment of different sizes can be placed in the first shielding drawer, through cooperative arrangement of the observation window and the observation glass, the effect of conveniently observing internal equipment is achieved, and through arrangement of the baffle, the equipment in the second shielding drawer can be protected, the effect of unified management of the equipment is achieved, students are prevented fromusing the equipment, and the safety is improved.

The invention discloses a heavy metal combined pollution soil remediation agent based on modified clay and a preparation method of the agent. The agent comprises 10-15wt% of a component A, 30-65wt% of a component B and 25-60wt% of a component C. The agent is a multi-component modified bentonite universal compound remediation agent used for treating multi-heavy-metal combined pollution soil; bentonite is adopted as a template of the agent, the different modified bentonite components can be prepared according to different modification methods, and then the component proportion of the agent can be adjusted according to the different types and contents of heavy metals in the soil; the component A contains sodium-based large-diameter bentonite particles which aim at heavy metal pollutants of relatively wide types; the component B contains inorganic pillar bearing modified bentonite particles which have an relatively good effect on stabilizing cationic heavy metal pollutants; the component C is organic modified bentonite particles which have a relatively good effect on stabilizing anionic heavy metal pollutants. Accordingly, the remediation effect on complex heavy metal pollution soil of the agent can be improved by adjusting the proportions of the three components.

The invention discloses a prevention and control method for debris flow induced by ice-lake break and an application of the method. The method comprises the steps of determining a flood peak flow threshold of break flood debris flow in combination with topographic and geomorphic characteristic parameters of a drainage basin, rainfall characteristic parameters, inner-source characteristic parameters of the drainage basin, transport capacity of a main river and the like; then judging the stability of a morainic dam body in each calculation area and performing classification of dangerousness based on basic parameters obtained by field investigation, sampling and indoor testing of the morainic dam body; and based on this, determining body shape parameters and a distribution mode of pile structure bodies in the morainic dam body. According to the method and the application, for the situation that sudden ice-lake break caused by buried ice melting in the morainic dam, ice landslides and entry of ice into a lake due to icefall easily forms a giant debris flow disaster, the dam body undercutting speed can be effectively controlled, the break flood discharge time can be prolonged, the peak flow of break flood can be reduced, and the scale of forming the debris flow by the break flood can be reduced, regulated and controlled, so that the risk of causing harm to a downstream zone of the ice lake by the break flood is lowered.

The invention discloses a subcritical composite solvent extraction separation method for multiple components in flaxseed meal. The method comprises the following steps: taking flaxseed meal, adding an extraction agent, and carrying out subcritical extraction to obtain a crude flax lignan extract and crude flaxseed oil in one step, wherein the extraction agent is composed of n-butane and absolute ethyl alcohol according to the volume ratio of 1: 1; adding n-hexane into the crude flaxseed oil, performing liquid separation extraction, and carrying out rotary evaporation to obtain flaxseed oil; and extracting the taken flaxseed meal with hot water to obtain flaxseed gum. The subcritical composite solvent used in the extraction process can replace a large amount of organic reagents used in traditional extraction, has the characteristics of good solvent effect, greenness, recyclability, small environmental burden and the like, and can reduce the risk of the organic reagents to operators and the natural environment in the process. And the subcritical extraction has lower requirements on operation and professionals, various high-added-value components are obtained while operation units are reduced, the resource utilization is maximized, and the cost is reduced, and the benefit is increased.

The invention discloses a soil arsenic and chromium pollution repairing agent based on an organoclay-loaded nano iron series. The repairing agent is prepared by mixing 55-85% of organic montmorillonite-loaded nano zero-valent iron and 15-45% of organic montmorillonite-loaded nano iron oxide by weight, wherein the organic montmorillonite-loaded nano zero-valent iron is obtained by reduction of nanozero-valent iron on iron-based montmorillonite particles and then organic modification; the organic montmorillonite-loaded nano iron oxide is obtained through organic modification of iron-based montmorillonite and then oxidation into nano iron oxide.

A preparation process for high-purity pregnant horse serum gonadotropin, comprising the following steps: (1) adjusting the pH of pregnant horse plasma to 3.0-4.0, separating solid and liquid, concentrating the filtrate, and adding alcohols to make the alcohols in the solution system The concentration is 30-55% (v / v), and after solid-liquid separation, alcohols are added to the filtrate to make the concentration of alcohols in the solution system 70-90% (v / v), and the obtained precipitate is dried, which is PMSG Crude product; (2) Add toluene derivative or ethylbenzene derivative solution to the PMSG crude product, after solid-liquid separation, the precipitate is added with alcohol, and the obtained precipitate is dried, which is the PMSG intermediate product; (3) The PMSG intermediate product is added Ammonium salt and / or calcium salt and / or potassium salt solution and alcohol substances, after solid-liquid separation, the clear liquid is added to ammonium salt and / or calcium salt and / or potassium salt solution and alcohol substances for a second time, after solid-liquid separation , adding alcohols to the supernatant to obtain a precipitate and dry it to obtain a refined product of PMSG.

The invention discloses a broccoli-flavored steamed cake and a preparation method thereof. The preparation method comprises the following steps: (1) preparation of broccoli puree; (2) heating of peanut oil; (3) preparation of an egg white batter; (4) preparation of an egg yolk liquid; (5) preparation of a cake batter; and (6) steaming of a cake. The broccoli flavored steamed cake prepared by usingthe preparation method provided by the invention is fluffy and delicious, has obvious broccoli flavor, avoids the harm of acrylamide generated by baking in virtue of steaming, and has simple operation and low cost; xylitol is used for completely replacing white granulated sugar, and the sugar content of the steamed cake is greatly reduced, so the risk of harm to the human body due to excess sugarintake is reduced, and the steamed cake provided by the invention is applicable to diabetic patients; and microwave-heated peanut oil is added into egg yolk, so the egg yolk can fully function as anemulsifier, and raw materials can be better and uniformly mixed.

The present application discloses a method for preparing the tip of an OCT catheter, which includes the following steps: pretreatment, heat-shrinking the diameter of one end of the imaging window tube to a preset value; welding for integration, and heat-shrinking the end of the imaging window tube It is welded together with the distal identification tube. The present application provides a method for preparing the tip of an OCT catheter. The diameter of one end of the imaging window tube is heat-shrunk to be consistent with the diameter of the distal marking tube through pretreatment, and then the pretreated imaging window tube is welded The end part is integrated with the distal marker tube by welding, and at the same time, after welding, the diameter of the inner wall of the butt joint is guaranteed to be consistent and smooth, so that the tip of the OCT catheter can be smoothly inserted or withdrawn from the guide wire, which greatly saves the operation time and reduces the operation time. possible risks.

The invention provides a comprehensive livestock and poultry breeding and harmless treatment system, which includes a breeding building provided with multi-layer breeding buildings and mobile high-temperature equipment that shuttles between the breeding buildings, and a lift elevator is arranged in the breeding building. The elevator is connected to each floor of the breeding house. The ground floor of the breeding building is the central control room. The central control room is provided with a transfer channel. The inner end of the transfer channel is connected to the elevator, and the outer end is connected to the outside of the breeding building. The mobile high-temperature equipment moves to the outside of the transfer channel. At the end, the high temperature harmless treatment of sick and dead livestock and poultry is carried out directly. Through the elevators, transfer passages and the like set up in the breeding building, the present invention enables the sick and dead livestock and poultry in the breeding buildings on each floor to be smoothly transported to the breeding building, and finally, the mobile high-temperature equipment that shuttles through the breeding buildings can be used for on-site harmless treatment. It will be in direct contact with the external environment, healthy livestock and poultry, personnel, etc., which significantly reduces the risk of harm caused by germs bred by sick and dead livestock and poultry.

The molecular gradient forward and reverse ultrafiltration separation and purification device disclosed in the present invention and its use method include an end sealer and at least two ultrafiltration units, and the ultrafiltration units include a tube body and an ultrafiltration membrane. The ultrafiltration membranes are arranged in the opposite direction, and the adjacent ultrafiltration units are detachably connected in the axial direction. The ultrafiltration membranes of the adjacent ultrafiltration units have different maximum molecular weights, and the ultrafiltration units at both ends are respectively connected to the end cappers. The invention can automatically separate and purify biomolecules in different intervals of molecular weight according to molecular gradient closed type, conveniently realize multiple times of forward and reverse purification, and facilitate graded collection of biomolecules in relevant intervals.