32 results about "Acrylamide" patented technology

The invention discloses a surface artemisinin molecule imprinting adsorbing material of a vegetable sponge. The material is characterized characterized by being prepared by the following steps of: preparing a polymer by selecting vegetable sponge as a substrate material, taking artemisinin as a template molecule, taking itaconic acid and acrylamide as functional monomers, taking ethylene glycol dimethacrylate as a cross-linking agent, taking azodiisobutyronitrile as an initiator and taking N,N-dimethylformamide as a solvent; and removing the artemisinin by using a hexane-diethyl ether mixed solution. The invention further provides a preparation method and an application method of the surface artemisinin molecule imprinting adsorbing material of the vegetable sponge. The surface artemisinin molecule imprinting adsorbing material of the vegetable sponge can separate the artemisinin with a structural analogue under normal pressure and temperature conditions; and the surface artemisinin molecule molecular imprinting adsorbing material of the vegetable sponge has the advantages of specificity, selectivity, good mechanical performance, good chemical stability, fast adsorbing speed, easiness for being eluted, biodegradability, simple process, regeneration capability, environmental friendliness and the like.

The invention discloses valid combinations of 8 novel SSR molecular markers and 2 known SSR molecular markers. The valid combinations are applied to strain identification. DNAs of 22 specific strains are taken as templates, 10 pairs of SSR primers are respectively utilized for carrying out PCR amplification, each pair of SSR primers is subjected to acrylamide gel electrophoresis after the PCR amplification, banding pattern statistic analysis is carried out according to all electrophoretic bands amplified from 22 samples, and therefore, a standard banding pattern of each pair of primers is determined; then the standard banding patterns of 10 pairs of primers of each sample are combined, and molecular identification cards of the 22 different strains of agaricus bisporus are constructed. According to an agaricus bisporus SSR molecular marker specific primer system and an application thereof, the strain identification effect of agaricus bisporus is improved; the agaricus bisporus SSR molecular marker specific primer system and the application are significant for the resource identification, the protection, the development and the utilization of agaricus bisporus.

The invention relates to a preparation method for an intelligent temperature-variable and immersion-proof shell fabric and a product thereof. The preparation method comprises the following steps: 1. temperature-variable copolymer of N-tert-butyl-acrylamide and acrylamide is obtained through the composition with a to b as the mole ratio of incoming stocks; wherein, the a lies between 60 and 40, and the b lies between 40 and 60; 2. a coating layer liquid is prepared according to the following concentration formulation by mass: 8 to 15 percent of the copolymer, 2.0 to 5.0 percent of a crosslinking agent that is 1,2,3,4-butane tetrabasic carboxylic acid and 0.5 to 2.5 percent of a catalyst that is sodium hypophosphite; 3.the coating layer liquid is used for coating a preprocessed fabric; 4. the immersion-proof shell fabric can be obtained through post processing. The product is produced by adopting the preparation method of the intelligent temperature-variable and immersion-proof fabric of the invention.

The invention discloses a coagulating agent for use in the treatment of wastewater containing fluorine and an application process thereof. The coagulating agent for use in the treatment of water containing fluorine is a composite coagulating agent prepared by adding a polymer organic additive during the synthesis of aluminium polychlorid; the polymer organic additive is a cationic polyacrylamide having a 10 to 30 percent amination degree and a 5 to 8 million molecular weight; and the mass of the added polymer organic additive is 1 to 10 percent of that of AlCl3.H20. The application process comprises: adding a modifier of lime milk into the wastewater containing fluorine to adjust the pH value of the wastewater containing fluorine to between 6 and 9; and adding the coagulating agent for use in the treatment of wastewater containing fluorine into the wastewater containing fluorine for coagulation in an amount of 900 to 1,500 milligrams of coagulating agent for use in the treatment of wastewater containing fluorine per liter of wastewater containing fluorine. The coagulating agent for use in the treatment of wastewater containing fluorine is low in raw material price and production cost, and the application process is simple, high in removal efficiency and low in investment cost and has the advantages of high efficiency and economy.

The invention relates to a phosphorus-free corrosion and scale inhibitor applicable to high-chlorine high-concentration-multiple circulating cooling water and a preparation method of the phosphorus-free corrosion and scale inhibitor, belonging to the technical field of water treatment. The technical problem to be solved by the invention is to provide the phosphorus-free corrosion and scale inhibitor with low toxicity, chloride resistance and low cost for high-concentration-multiple circulating cooling water containing high-concentration chloride ions. The phosphorus-free corrosion and scale inhibitor is prepared from the following raw materials in parts by weight: 3 to 5 parts of zinc sulfate, 4 to 7 parts of sodium gluconate, 2 to 4 parts of sodium molybdate, 0.5 to 2 parts of benzotriazole, 5 to 9 parts of and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, 7 to 12 parts of polyepoxysuccinic acid and 3 to 5 parts of hydrolyzed polymaleic anhydride. Compared with similar corrosion and scale inhibitors, the phosphorus-free corrosion and scale inhibitor for high-concentration-multiple circulating cooling water provided by the invention has the advantages of strongtargeting performance, low toxicity, chloride resistance, low cost, simple operation, convenience, rapidness, environmental friendliness, safety, high efficiency and the like.

The invention discloses a preparation method of a flexible electrode membrane based on polyacrylamide hydrogel. The preparation method comprises the following steps: 1) weighing the following raw materials: polyacrylamide powder, sodium chloride powder and water according to corresponding mass percentages; 2) dissolving the sodium chloride powder in water to obtain a sodium chloride solution, adding the polyacrylamide powder, and performing stirring until a gel-like flexible gel is formed; and 3) standing the flexible gel in step 2) at normal temperature, and stretching the flexible gel untilcomplete transparence to obtain the flexible electrode membrane based on the polyacrylamide hydrogel. The preparation method has the advantages of high efficiency, low preparation cost, environmentalprotection, safety, good stability, and high conductivity of the prepared flexible electrode membrane.

The invention discloses a temperature-sensitive wall material. The temperature-sensitive wall material comprises a temperature-sensitive material modified polymer wall material, wherein the temperature-sensitive material is polyvinylpyrrolidone, glycerophosphate, stearic acid, galactose-removed xyloglucan or gelatin-chitosan, poly(N-isopropylacrylamide) and hydroxybutyl chitosan. The temperature-sensitive wall material releases drugs at different temperatures, the drug release time is flexibly controlled, the phytotoxicity is reduced, and the drug action time is prolonged. The temperature-sensitive wall material can be applied to whole-course pesticide application protection of the growth cycle of crops, the chemical application frequency is reduced, and the crop management efficiency is improved. The invention also provides a corresponding microcapsule and a preparation method.

The invention discloses epoxy emulsion cured at room temperature with high aquosity and weather resistance as well as a preparation method of the epoxy emulsion. The epoxy emulsion comprises the following components in percentage by weight: 15-20 percent of E-20 epoxy resin, 5-10 percent of E-12 epoxy resin, 1.0-1.5 percent of benzoyl peroxide, 4.0-6.0 percent of methacrylic acid, 3.0-8.0 percent of hexafluorobutyl acrylate, 0.5-2.5 percent of diacetone acrylamide, 0.5-2.5 percent of adipic acid dihydrazide, 10-20 percent of ethylene glycol monobutyl ether, 5-10 percent of n-butyl alcohol, 3.5-5.5 percent of N,N-dimethylethanolamine and 22-40 percent of water. The preparation method comprises the following steps: firstly, adding E-20 epoxy resin, E-12 epoxy resin, n-butyl alcohol and ethylene glycol monobutyl ether to be evenly dissolved; then, dipping mixed solution of benzoyl peroxide, methacrylic acid, hexafluorobutyl acrylate, diacetone acrylamide and adipic acid dihydrazide to be reacted; and adding N,N-dimethylethanolamine and water to prepare the epoxy emulsion. The epoxy emulsion and the preparation method of the epoxy emulsion have the characteristics of weather resistance, abrasive resistance, water resisting property, alkali resistance, corrosion resistance, flexibility, washable resistance, environment protection and simple preparation process.

The invention discloses a straight-chain liquid AKD surface sizing agent and a preparation method thereof. The straight-chain liquid AKD surface sizing agent is prepared from the following raw materials in parts by weight, 100-200 parts of starch, 1000-2000 parts of water, 4-8 parts of sodium hydroxide, 25-50 parts of a cationic etherifying agent, 5-10 parts of a dilute acid, 15-30 parts of a cationic monomer, 25-50 parts of acrylamide, 1-2 parts of an initiator, 5-10 parts of a dispersing agent, 20-50 parts of an AKD special cationic polymer emulsifier, and 60-150 parts of liquid AKD. The molecular structure of the straight-chain liquid AKD adopted by the invention has a lactone ring structure; reacting under neutral and alkaline conditions; the reaction functional groups and hydroxyl groups on fiber molecules are subjected to esterification reaction to be firmly bonded on the surfaces of the fibers; the hydrophobic long-chain fatty group turns to the paper surface, so that the hydrophobic effect is obtained, the stability and the sizing effect of the AKD surface sizing agent are remarkably improved by adding the AKD special cationic polymer emulsifier, meanwhile, the hydrolysis and migration tendency of AKD is limited, and AKD latex is well protected.

The invention relates to the technical field of chain teeth and in particular relates to a transparent flashing polyester chain tooth, a preparation method and a zip fastener. The transparent flashingpolyester chain tooth is prepared from PET (Polyethylene Terephthalate), TPU (Thermoplastic Polyurethane) modified master batch, a lubricant, an antioxidant and an ultraviolet absorbent, wherein theTPU modified master batch is prepared from isocyanate, polyol, a chain extender, a crosslinking agent and flashing powder; the flashing powder is composed of a micron-grade prism pyramid monomer polyacrylamide layer. According to the transparent flashing polyester chain tooth, the TPU modified master batch with relatively good toughness is added into a PET material, so that the transparent flashing polyester chain tooth has good toughness and anti-impact performance; furthermore, the surface of a micron-grade prism pyramid monomer is covered with the polyacrylamide layer and the crosslinking agent participates, so that the micron-grade prism pyramid monomer is uniformly dispersed in the PET material; compared with a manner of directly adding the micron-grade prism pyramid monomer or the flashing powder into the PET material, the transparent flashing polyester chain tooth has a more uniform and bright flashing property.

The invention provides straw-based composite filler. The straw-based composite filler is a compound with a core-shell structure, wherein straw powder particles are used as a core of the compound with the core-shell structure; a cladding film which is grafted with the straw powder particles and contains an acrylamide copolymer is used a shell layer of the compound with the core-shell structure; the straw powder particles are particles which are obtained by crushing straw powder to 30 meshes to 200 meshes; the cladding film shell layer containing the acrylamide copolymer is formed by copolymerizing monomers (a), (b) and (c). The novel straw-based composite filler provided by the invention has the core-shell structure; a surface polymer film of the shell layer has a function of not desorbing and also has hydrophily and cationic property; when the straw-based composite filler is used for paper filling, the net retention rate is kept, even improved, and the effects of enhancing and toughening can be realized. Therefore, properties of the straw-based composite filler can be sufficiently utilized and the straw-based composite filler is used as special filler of the paper.

The invention provides sports outdoor clothing fabric for the mass. The sports outdoor clothing fabric is prepared by the following method: S1, selecting low-elasticity interlaced yarns as warp yarnsand selecting polyester fibers with specially-shaped sections as weft yarns to weave polyester fabric; S2, washing and drying the polyester fabric; S3, soaking the polyester fabric into a diphenyl ketone-acetone solution, and shading and airing; S4, soaking the polyester fabric attached with benzophenone on surface into an acrylamide aqueous solution, and placing into an irradiation reactor to perform vacuum-pumping; S5, turning on a lamp to irradiate to obtain modified fabric; S6, putting the modified fabric into an acetone solution, and cleaning and drying; S7, soaking the dried fabric intodeionized water, sufficiently wetting, dropwise adding epoxy resin to react, and washing and drying; and S8, soaking the fabric into deionized water, adding collagen powder, and continuously reactingand drying. The fabric has gas permeability, moisture penetrability and wet permeability which are superior to that of cotton woven fabrics with similar specifications.

The invention discloses a preparation method of cellulose-based conductive hydrogel. The method comprises the following steps: adding cellulose into a zinc chloride solution, and grafting monomers onto the cellulose under the action of an initiator, wherein the monomers are acrylonitrile and acrylamide, According to the invention, the hydrogel is prepared by adopting a one-step method, the processis simple and easy to operate, and the prepared hydrogel has excellent tensile property, compression resistance, frost resistance and conductivity, and also has excellent conductivity at low temperature.

The invention discloses a preparation method of a filtering material for adsorbing fluorine ions in water, and a preparation method, wherein Al-PAM, NaOH, diethylenetriamine, carbon disulfide, (NH4)2CO3, AlCl3 and a monomer acrylamide are used main raw materials, an adsorbent uses a metal hydroxide colloid as a base material, and a large number of polyacrylamide polymer branch chains are grafted on the surface of nanoparticles to obtain an organic-inorganic hybrid flocculating agent. According to the present invention, the raw materials are simple, the preparation process and the treatment process are simple, the chemical stability is high, the method is easy to implement in practical applications, and the product has excellent adsorption effect on fluorine ions in water.

The invention discloses a polyacrylate grafted graphene oxide plugging agent and an oil-based drilling fluid. A plugging agent used by the oil-based drilling fluid is polyacrylate grafted graphene oxide, and the polyacrylate grafted graphene oxide plugging agent is prepared from the following synthetic raw materials: graphene oxide, an amino silane compound, an acrylate compound and an acrylamide compound. The drilling fluid comprises the polyacrylate grafted graphene oxide blocking agent disclosed by the invention. The polyacrylate grafted graphene oxide is used as a blocking agent, the particle size of the polyacrylate grafted graphene oxide is approximately distributed between 60 nm and 1200 nm, nano apertures in a shale stratum can be effectively blocked, and therefore the well wall can be effectively stabilized, and collapse can be prevented; the plugging agent has small influence on the performance of the drilling fluid and is beneficial to reducing the filter loss of the drilling fluid, and the oil-based drilling fluid used by the plugging agent has good rheological property, water loss wall-building property, plugging property and the like under the shale formation condition.

The invention belongs to the technical field of water-soluble polymer material, and in particular relates to a preparation method of a high-solid content polypropylene papermaking reinforcing agent. According to the method, raw materials such as acrylamide, crylic acid, ammonium persulfate and sodium sulfite are adopted to prepare a papermaking reinforcing agent through an aqueous solution polymerization technology, so that problems of low solid content and poor water solubility in the prior art are solved. By utilizing the preparation method, the polymer molecular weight and solid content are improved, the transportation cost and production cost are effectively lowered, and the obtained product has reinforcing, retension and dispersing effects and good dissolvability and can be completely dissolved in the water after soaking in the water, so that the utilization rate of the product is increased, and the product has a wide market prospect and an obvious economic benefit.

The invention discloses environment-friendly impermeable composite bentonite, and belongs to the field of green chemistry and environmental protection. The composite bentonite is prepared from the following components in parts by mass: 1000-1200 parts of bentonite, 90-120 parts of sodium carbonate, 300-500 parts of a biodegradable polyester material, 50-100 parts of a cross-linking agent, 30-50 parts of a drying agent and 30-50 parts of a preservative; wherein the bentonite is granular bentonite; the biodegradable polyester material is one of poly (trimethylene carbonate), polycaprolactone andpolyvalerolactone; the cross-linking agent is N-hydroxymethyl acrylamide; the drying agent is at least one of bamboo charcoal and quartz sand; and the preservative is copper sulfate. By adding the biodegradable material and the cross-linking agent, the composite bentonite has good anti-seepage performance, can be biologically degraded, and has a wind indicator effect on the development of green chemistry.

The invention belongs to the field of water-soluble high molecular materials, and in particular relates to a method for industrially preparing polyacrylamide reverse-phase emulsion. A polyacrylamide reverse-phase emulsion product is obtained by adopting a multi-step polymerization step. The method comprises the following steps: step 1, by taking acrylamide and acrylic acid or 2-acrylamido-2-methylpropanesulfonic acid as a polymerization monomer and taking Span and octylphenol polyoxyethylene ether (OP) as an emulsifier, carrying out a small amount of polymerization to prepare the polyacrylamide reverse-phase emulsion, wherein polymerization heat is less so as to ensure that implosion dangers, caused by the fact that heat is not dissipated in time, do not occur in a polymerization process; step 2, polymerizing: carrying out further polymerization on the basis of the polymerization in the step 1, wherein partial polymerization is carried out, so that polymerization heat generated by the polymerization in step 2 is greatly reduced, an implosion phenomenon does not occur, and gel or emulsion breaking is not generated in the polymerization process. In a subsequent polymerization process, the released amount is determined according to the size of a polymerization kettle and heat releasing efficiency when one part of product is released each time. By adopting the method provided by the invention, the safety of polymerization reaction is greatly improved, the large-size polymerization kettle can be utilized, and the implosion possibility does not need to be worried, so that industrial production can be stably and safely carried out.

The invention provides a preparation method of a composite efficient coagulant for treatment of textile printing and dyeing wastewater, belonging to the technical field of wastewater treatment. The preparation method comprises the following steps: roasting fly ash, carrying out secondary acid leaching extraction, performing filtering, collecting filtrates, and combining the filtrates for later use; dissolving sodium silicate in a certain amount of deionized water, adjusting a pH value with hydrochloric acid, carrying out a reaction for 3-6 h, dropwise adding the filtrate and a cerium oxide solution, carrying out a stirring reaction for 10-15 min, adding chitosan, carrying out a reaction for 5-10 min, adjusting the pH value with sodium hydroxide, and carrying out a stirring reaction for 3-6h; adding disodium hydrogen phosphate into the reaction solution, and then carrying out stirring and heating to 40-50 DEG C; then, adding polydimethyldiallyl ammonium chloride and starch modified polyacrylamide, continuing stirring for a reaction for 1-2 h, performing standing, and carrying out curing for 20-25 h. According to the invention, a variety of coagulation components are matched with one another, so the composite efficient coagulant has good treatment effect on textile printing and dyeing wastewater, wherein the removal rate of COD achieves 94%, and the removal rate of TOC achieves97.9%; and the composite efficient coagulant has outstanding charge neutralization ability.

The invention provides a bone gelatin wastewater treatment method. The bone gelatin wastewater treatment method comprises the following steps: S1, collecting liming workshop wastewater; s2, collecting wastewater of a pickling workshop; s3, collecting other wastewater in the production process; s4, all the wastewater is introduced into a comprehensive adjusting tank to be mixed, and mixed wastewater is obtained; s5, introducing the mixed wastewater into a reaction tank, adding Na2CO3, then adding polyacrylamide, and fully reacting to obtain a reaction solution; s6, carrying out solid-liquid separation on the reaction liquid, and feeding obtained sludge into a sludge tank for recycling and post-treatment; s7, the supernate enters a pH adjusting pool, dilute sulphuric acid is added, and a mixed solution is obtained after reaction; s8, enabling the mixed solution to pass through an anaerobic tank, an anoxic tank and an aerobic tank to obtain a treatment solution; and S9, introducing the treated liquid into a secondary sedimentation tank, separating, metering and discharging the supernatant, returning the settled sludge to an anaerobic tank, supplementing the sludge concentration, and carrying out dewatering treatment on the residual sludge. The bone gelatin wastewater treatment method disclosed by the invention is low in calcium ion content and small in impact on the biochemical environment.

The invention discloses flame-retardant waterproof wall cloth and a preparation method thereof.The wall cloth sequentially comprises a base layer, a flame-retardant layer and a waterproof layer from inside to outside, the flame-retardant layer is a modified low-density polyethylene film, the waterproof layer is prepared from paint, and under the action of high-energy rays, the flame-retardant layer is a flame-retardant waterproof layer. The low-density polyethylene resin and the acrylamide monomer can generate a large number of free radicals, polymerization reaction and cross-linking reaction are carried out, then the modified low-density polyethylene film is obtained, the polyacrylamide has the characteristics of high strength and flame retardance, the strength of the low-density polyethylene resin can be improved by grafting the polyacrylamide on the low-density polyethylene resin, and the low-density polyethylene film is prepared. Meanwhile, silicon dioxide is subjected to alkylation modification, alkyl groups and halogen elements are introduced, the hydrophobic performance of the coating is enhanced, and then the waterproof performance of the wall cloth is improved.

The invention discloses an OPP (oriented polypropylene) heat dissipating and insulating release film. The OPP heat dissipating and insulating release film comprises OPP, ceramic powder, epoxy resin 6101, furfural furfuryl alcohol resin, melamine, polyacrylamide, polyamide 66, nano-alumina, mica, talc, poly(vinyl butyral), PFA (perfluoroalkoxy alkane), PBT (polybutylece terephthalate), PET (polyethylene terephthalate), methoxypolyethylene glycols, PTFE (polytetrafluoroethylene), polymethylmethacrylate, polyphenylene sulfide, glass fibers, organic montmorillonite, paraffin, polyetheretherketone fiber, nano-SiO2, an antioxidant 1010, a light stabilizer 622, nano-TiO2, PP-g-MAH (maleic anhydride grafted polypropylene), a thickener and a coupling agent. The OPP heat dissipating and insulating release film has excellent insulation, water resistance, corrosion resistance, temperature resistance, weather resistance, adhesiveness as well as heat dissipation and energy storage functions.

The invention discloses water-based plastic ink which is prepared from the following raw materials in parts by weight: 65-85% of water-soluble acrylic resin, 15-25% of water-based color paste, 10-20% of deionized water and the balance of ammonia water, wherein the water-soluble acrylic resin is prepared from the following raw materials in parts by weight: 12-18 parts of methyl methacrylate, 12-18 parts of butyl acrylate, 4-8 parts of acrylic acid, 1.5-2.5 parts of hydroxyethyl acrylate, 0.5-1 part of diacetone acrylamide, 33-46 parts of propylene glycol methyl ether acetate, 16-23 parts of dimethyl formamide, 3-6 parts of polyoxyethylene ether, 1-3 parts of polyoxyethylene glycol alkyl ester, 0.5-2 parts of dimethylaminoethanol, 0.5-1 part of azodiisobutyronitrile, 0.5-0.8 parts of adipic acid dihydrazide and 80-160 parts of distilled water. According to the water-based plastic ink disclosed by the invention, the water-soluble acrylic resin is taken as a vehicle, so that the water-based plastic ink can maintain good coating colorability and good adhesive force on a PE/PP (polyethylene/polypropylene) film.

The invention discloses a 3D honeycomb type paint mist filter bag and a preparation method thereof. The preparation method comprises the four steps of preparing pyrrole-based polystyrene, preparing pyrrole-based polystyrene cross-linked glass fibers, preparing a 3D honeycomb type filter material and preparing the paint mist filter bag. According to the invention, acrylamide, polyvinyl alcohol and the pyrrole-based polystyrene cross-linked glass fibers are compounded to obtain the 3D honeycomb type filter material, the filter material is endowed with good recovery capacity through the dynamic ionic cross-linking effect of hydroxyl and borate ions of polyvinyl alcohol, and the pyrrole-based polystyrene cross-linked glass fibers and the polyvinyl alcohol form a good 3D network structure. In addition, carboxymethyl starch and acrylamide form a layer of compact composite filter membrane on the surfaces of the glass fibers, and the 3D honeycomb type filter material can be effectively fixed on the surfaces of the glass fibers. Meanwhile, the compactness and the connection strength of the glass fibers are enhanced, and the network structure of the 3D honeycomb type filter material and abundant pore structures on the surfaces of the glass fibers are beneficial to adsorption of paint mist.

The invention discloses a waterproof material for polystyrene boards and gypsum boards of building walls. The waterproof material is prepared from the following raw materials in parts by weight: 8-10parts of cement clinker, 6-10 parts of quick lime, 10-15 parts of a polyethylene emulsion, 15-20 parts of a paraffin emulsion, 4-8 parts of glass fibers, 3-6 parts of borax, 3-6 parts of sodium alginate, 3-5 parts of a grinding aid, 3-4 parts of sodium methyl silicate, 2-6 parts of hydroxyethyl cellulose, 2-4 parts of sodium tripolyphosphate, 2-4 parts of triethanolamine, 2-3 parts of aluminum potassium sulfate, 2-3 parts of dodecyl ethyoxyl sulphobetaine, 1-3 parts of polyacrylamide, 1-2 parts of calcium lignosulphonate and 50-80 parts of water. During construction, only 1mm of the material needs to be smeared on a polystyrene board wall body and a gypsum board wall body, after air drying, the surface layer of the wall surface is cleaned and polished to be flat, construction is convenient, time and labor are saved, the polystyrene board wall body and the gypsum board wall body treated through the material can completely eradicate the phenomena of alkali efflorescence, falling, moisture regain, mildewing and hollowing of the wall bodies, the service life of the polystyrene board and the gypsum board of the building wall body is greatly prolonged, and the cost is low.