226 results about "Acid catalysis" patented technology

The invention discloses a method for preparing 12-mercaptan through solid organic acid catalysis, belongs to the technical field of 12-mercaptan preparation, and aims to solve the problems of low catalyst activity, harsh reaction conditions, serious pollution, high cost and dependence on import in the prior art. N-dodecanol and hydrogen sulfide are used as raw materials and are mixed according to the molar ratio of 1: 1.2-1: 1.3; the method comprises the following steps: gasifying n-dodecanol, mixing with purified hydrogen sulfide, preheating to 210-240 DEG C, introducing into a fixed bed reactor filled with a solid organic acid catalyst, and reacting at-0.08-3.0 MPa for 3.5-4 hours; and cooling and condensing the reaction product, carrying out gas-liquid separation, rectifying and purifying the liquid product to obtain 12-mercaptan with the purity of more than or equal to 99.5%, and recycling unreacted hydrogen sulfide. The solid organic acid can be a catalyst of p-toluenesulfonic acid and the like or mesoporous silica loaded nickel, cobalt and molybdenum metal oxides. The method has the advantages of high catalytic activity, mild reaction conditions, high product yield (the conversion rate of n-dodecanol is greater than or equal to 94.5%), environmental protection and low cost, can realize the domestic mass production of 12-mercaptan, and meets the market demand.

The invention discloses a phenanthridine-6-formaldehyde derivative and a preparation method and application thereof.The preparation method comprises the steps that 2, 4, 5, 6-tetra (9-carbazolyl)-isophthalonitrile serves as a photocatalyst, 1-azabicyclo [2.2. 2] octane serves as a hydrogen atom transfer catalyst, a biphenyl isocyanide compound, the photocatalyst, the hydrogen atom transfer catalyst and an alkali additive are jointly dissolved in 1, 3-dioxolane, the mixture is stirred to be uniform, and the phenanthridine-6-formaldehyde derivative is obtained. And carrying out free radical tandem cyclization and acid-catalyzed hydrolysis reaction to obtain the phenanthridine-6-formaldehyde derivative. The invention also provides a specific reaction equation. According to the developed synthesis method of the phenanthridine-6-formaldehyde derivative, the compound can be efficiently and conveniently prepared, the technical bottlenecks of harsh reaction conditions and tedious steps in a traditional process are successfully overcome, raw materials which are low in price and easy to obtain are adopted, operation is carried out under mild conditions, the synthesis method has the outstanding advantages of being high in yield, safe and simple to operate, environmentally friendly and the like, and the method is suitable for industrial production. Good industrial application potential is shown.

The invention provides a functional nanofiber material as well as a preparation method and application thereof, and the preparation method comprises the following steps: (1) adding raw materials into water to form an electrostatic spinning solution; performing electrostatic spinning to obtain a nanofiber membrane; (2) cross-linking the nanofiber membrane in an organic solvent under the catalysis of acid to obtain a cross-linked nanofiber membrane; and (3) carrying out grafting reaction on the cross-linked nanofiber membrane in a polyamine cross-linking agent, and then reacting with a sulfur-containing reagent to obtain the functional nanofiber material, the functionalized nanofiber material prepared by the preparation method disclosed by the invention combines good biocompatibility of polyvinyl alcohol, high specific surface area and high porosity of nanofiber and a synergistic adsorption effect of the polyamine cross-linking agent and cysteine, and has the advantages of large adsorption capacity, high adsorption rate, strong selectivity, good biocompatibility, stable structure and the like; the heavy metal ions in the plasma can be efficiently and safely removed, and a plurality of defects of the existing adsorption material are overcome.

The invention discloses an application of an ionic liquid in extraction of trioxymethylene, in the process of generating trioxymethylene by acid-catalyzed condensation of a formaldehyde aqueous solution, the ionic liquid is added as an extraction agent to extract and separate the trioxymethylene generated by reaction, and the ionic liquid is methyl tributyl phosphonium bis (trifluoromethanesulfonyl) imide salt; when the ionic liquid is used for extracting trioxymethylene, a ternary azeotropic system of trioxymethylene, water and methylene glycol can be broken, the ionic liquid and trioxymethylene are subjected to nonpolar Van der Waals' force interaction so as to realize extraction, and methylene glycol and water are left in a water phase through hydrogen-bond interaction, so that high-purity trioxymethylene with the purity of more than or equal to 99.5 wt.% is obtained.

The invention discloses a precise construction strategy of a dibenzothiophene sulfuryl covalent organic framework material and systematically explains efficient application of the dibenzothiophene sulfuryl covalent organic framework material in photocatalytic synthesis of thiadiazole and derivatives thereof. The achievement relates to a plurality of leading subjects such as catalytic chemistry, organic synthesis, material science, environmental engineering and green chemistry. According to the method, 2, 4, 6-triformyl phloroglucinol and 3, 7-diaminodibenzo [b, d] thiophene-5, 5-dioxide are taken as construction units, and the crystalline S-COF rich in sulfuryl active sites can be quantitatively obtained through topology-oriented Schiff base condensation under the conditions of protonic acid catalysis, no water and no oxygen. Under the radiation condition of visible blue light, S-COF is used as a heterogeneous photocatalyst to drive green synthesis of 3, 5-di-p-tolyl-1, 2, 4-thiadiazole and series of derivatives thereof; the invention provides a new catalyst design normal form for light-induced organic conversion, and lays a solid foundation for sustainable development-oriented efficient synthesis chemistry.

The invention belongs to the technical field of membranes, and discloses a monovalent / divalent cation selective separation membrane based on an intrinsic microporous polymer, and the preparation route of the membrane is as follows: taking an ether-free polymer synthesized by super acid catalysis as a precursor, introducing an ion exchange site into the polymer by utilizing grafting of a sulfonated monomer, and preparing the monovalent / divalent cation selective separation membrane based on the intrinsic microporous polymer. And improving the separation performance of monovalent ions / divalent ions by using an alkoxy chain graft with specific interaction on the monovalent ions, and greatly improving the mechanical strength of the membrane by using the interaction of hydrogen bonds between main and side chains, thereby finally obtaining the monovalent / divalent cation selective separation membrane. According to the present invention, the industrial production difficulty is significantly reduced by the full solvation reaction membrane synthesis route, the selectivity of the prepared membrane material is superior to the selectivity of the commercial membrane of the same type, the extremely high mechanical strength is maintained, and the large-scale production and application potential is provided.

The invention discloses a method for catalyzing melamino-formaldehyde resin methylation reaction by solid acid. According to the invention, epoxy silane coupling agent grafted modified nanocellulose is introduced into sulfonated styrene-divinyl benzene cross-linked copolymer microspheres for in-situ crystal cross-linking, so that the problems that the traditional sulfonated polystyrene resin is poor in mechanical strength and solution solubility resistance, low in cycle index, easy to swell and fall off and the like are effectively solved; the prepared solid acid resin has the characteristics of high reaction activity, high proton transfer rate, high mechanical strength, high cyclicity and easiness in solid-liquid separation, and by utilizing the solid acid resin to catalyze the etherification reaction of the melamino-formaldehyde resin, the reaction temperature and the production energy consumption are reduced, the reaction time is shortened, the product quality and the production efficiency are improved, and the production cost is reduced. The problems of environmental protection and energy consumption caused by the generation of a large amount of VOCs in the etherification reaction of the traditional liquid catalyst for synthesizing the high-etherified melamine formaldehyde resin and the by-product inorganic salt in the subsequent process are solved.

The invention provides an antibacterial high-barrier starch-based plastic bottle and a preparation method thereof.The preparation method comprises the steps that firstly, titanate generates nano titanium dioxide in situ in starch through acid catalysis, starch is subjected to in-situ hybridization modification, and nano titanium dioxide in-situ hybridization starch is prepared; then adding nano inorganic barrier powder, and then adding a long-chain silane coupling agent to modify the nano titanium dioxide in-situ hybridized starch and the nano inorganic barrier powder to obtain a modified starch compound; performing vacuum kneading and drying until the water content is lower than 0.5%, and adding an antibacterial lubricant for plasticizing to obtain a plasticized material; and finally, carrying out melt blending and granulation with polyolefin resin, and carrying out extrusion blow molding. The environment-friendly and low-cost starch-based material is kept, meanwhile, the comprehensive performance of the product is remarkably improved, the surface contact angle of the product is 110 degrees or above, the antibacterial rate is 97% or above, and the oxygen permeation amount and the water vapor permeation amount are 100 cm / (m.24h. Atm) and 4 g / (m.24h) or below respectively.

The invention belongs to the technical field of biology, and discloses a transaminase GabT1 mutant S106I, a construction method thereof and application of the transaminase GabT1 mutant S106I in biosynthesis of 1-deoxynojirimycin. According to the invention, the 106th serine near the molecular catalytic domain of the transaminase GabT1 derived from bacillus amyloliquefaciens is mutated into isoleucine in a site-directed mutagenesis manner, so that the catalytic efficiency of the transaminase GabT1 is remarkably improved, the problem that the catalytic efficiency of the transaminase GabT1 on fructose-6-phosphoric acid is not high at present is solved, and the application of the transaminase GabT1 to the fructose-6-phosphoric acid is promoted. The yield of 1-deoxynojirimycin synthesized by the mutant GabTS106I is increased by 43.87% compared with that of a wild type. The 1-deoxynojirimycin fermentation production capability of the transaminase GabT1 mutant and the engineering strain obtained by the invention is greatly improved, and the transaminase GabT1 mutant and the engineering strain have a good industrial application prospect.

Anion exchange polymers comprise a plurality of repeating units of formula (I). The polymer may be synthesized from a super acid catalyzed polyhydroxyalkylation reaction of monomers Ar1′, Ar2′, and X1′ to form a neutral precursor polymer followed by a Menshutkin reaction to convert the neutral precursor polymer to the anion exchange polymer.Anion exchange membranes and membrane electrode assemblies incorporating the anion exchange polymers are also described.

The application relates to a method for hydrothermal acid-controlled degradation of mulberry leaf polysaccharide and antioxidant application thereof, and belongs to the technical field of extraction of active ingredients in natural products. The method comprises the following steps: pretreating raw materials, hydrothermally reacting and acid-catalytically treating mulberry leaves, and alcohol-sedimenting, separating and purifying mulberry leaf polysaccharide, so as to obtain mulberry leaf polysaccharide, finally, the antioxidant application of the mulberry leaf polysaccharide is explored, and a theoretical basis is provided for development of mulberry leaf resources. The method can not only obtain mulberry leaf polysaccharide, but also obtain high-value natural active ingredients such as rutin, astragalin, scopoletin and isoquercitrin in the mulberry leaves, is beneficial to development and utilization of the mulberry leaf resources, meets the needs of people's health, and has practical significance and economic value.

The invention provides an anti-interference control method for the concentration of a main reactant in a continuous stirring reaction kettle process, belongs to the technical field of chemical process control, and solves the problem that in the chemical process of producing cyclopentanol by catalyzing electrophilic water with cyclopentadienoic acid, the concentration of the main reactant is not influenced. The technical problem that the concentration of a main reactant is difficult to track a set value without steady-state errors under the conditions of fluctuation of feeding concentration, uncertainty and external disturbance of the continuous stirring reaction kettle is solved. According to the technical scheme, the method comprises the steps of constructing a model pre-estimation compensator and an anti-interference control structure, designing a four-dimensional decision model, carrying out parameter collaborative optimization by adopting a multi-target genetic optimization algorithm, and carrying out optimal solution selection based on a TOPSIS method. Under the condition of feed concentration fluctuation, the dynamic response speed and the anti-interference capability of the system can be remarkably improved, and faster adjustment time, smaller overshoot and stronger robustness can be realized in linear and nonlinear models.

The application discloses a cross-linked polyaryl piperidine anion exchange membrane and a preparation method and application thereof, and relates to the technical field of anion exchange membranes. The anion exchange membrane takes polyaryl piperidine as a skeleton, introduces crown ether structure and a cross-linked network, and solves the technical problem that the balance between the hydroxyl ion conductivity and the dimensional stability is difficult in the existing anion exchange membrane. The anion exchange membrane comprises a specific structure of a repeating unit, is prepared through Friedel-Crafts superacid catalytic polymerization, Menshutkin reaction functionalization and Michael addition reaction cross-linking, and has excellent hydroxyl ion conductivity, dimensional stability, chemical stability and mechanical strength. The preparation method is simple in operation, fast in polymerization rate, and high in conversion rate, does not need to strictly control the temperature and oxygen of a reaction environment, is suitable for the field of water electrolysis hydrogen production, especially suitable for an anion exchange membrane water electrolysis system, and has a wide industrial application prospect.

The invention belongs to the technical field of medicine synthesis, and discloses a preparation method of a sodium nitroprusside raw material medicine. According to the method, weak acid is adopted for catalysis, the effect of remarkably reducing generation of toxic substances such as cyanide and nitrogen dioxide is achieved by controlling the material dripping speed and the dripping pH, the reaction is mild, the technological operation is safe and controllable, and industrial production of the sodium nitroprusside raw material medicine is facilitated. According to the preparation method of some examples, silica gel filtration is used for post-treatment, the residual risk of impurities such as sodium ferricyanide, ferric ferrocyanide and ferric ferricyanide is reduced, and the purity of the raw material medicine is larger than or equal to 99.9% and is far superior to the requirements of pharmacopoeia of various countries.

The present application relates to a kind of preparation method of evocacet and its intermediate, it is the improvement of evocacet synthesis process, using cheap and readily available copper / amino acid catalyst combination, evocacet intermediate is obtained with high yield and high selectivity, compared with prior art reduces production cost.

The application discloses a preparation method of a mesoporous silicon-based composite material with phosphotungstic acid and titanium oxide simultaneously supported, and belongs to the technical field of catalytic material preparation. The method aims to solve the problems of easy aggregation of active components, easy damage of channel order and complex preparation process in the prior art. The method is characterized by the following steps: through a one-step hydrothermal synthesis strategy, a triblock copolymer is used as a structure directing agent, an alcohol solution of a titanium source precursor, a silicon source precursor and a Keggin type phosphotungstic acid is simultaneously added in an acid system, and then the mesoporous silicon-based composite material is prepared through hydrothermal crystallization, washing, drying and calcination. The method is simple in process and controllable in operation, and the obtained material has the following advantages: two-dimensional hexagonal ordered mesoporous structure, large specific surface area, high dispersion of titanium and phosphotungstic acid, intact Keggin structure, good double-acid-site synergistic catalytic effect, and suitability for acid catalytic reactions, especially in the field of biomass conversion.

The invention belongs to the technical field of photocatalytic materials, and discloses a triazine-hydrazine bond-based efficient water photolysis COF material as well as a preparation method and application thereof. The material is prepared by carrying out condensation polymerization reaction on benzo [1, 2-b: 3, 4-b ': 5, 6-b'] trithiophene-2, 5, 8-tricarboxaldehyde, 4, 4 ', 4' '-(1, 3, 5-triazine-2, 4, 6-triyl) tribenzaldehyde and hydrazine hydrate. An intramolecular donor-acceptor (D-A) electronic structure is constructed by introducing an electron-rich benzotrithiophene unit and an electron-deficient triazine unit, and the electron-deficient triazine unit and the electron-deficient triazine unit are connected through a full-conjugated azine bond, so that separation and transmission of photo-generated charges are effectively promoted. The preparation method adopts a solvothermal method, and a high-crystallinity product is obtained through acid catalysis and degassing crystallization. The material has high specific surface area and excellent chemical stability, and shows high-efficiency photocatalytic water splitting hydrogen production activity and good cycle stability under the driving of visible light.

The invention provides a production system and a production method of 3-methoxy-N, N-bis (2-ethoxyl) aniline. According to the production method, functionalized ionic liquid ([HEMIM] HSO4, [HEMIM] H2PO4, [APMIM] HSO4 and [APMIM] H2PO4) and triethylamine are adopted to construct an efficient synergistic catalysis system. Amino (-NH2) or hydroxyl (-OH) of a cation side chain of the ionic liquid is combined with nitrogen atoms of triethylamine through hydrogen bonds, meanwhile, acidic anions (HSO4 <-> / H2PO4 <->) of the ionic liquid and protonated triethylamine ([H-TEA] < + >) generated in the reaction can form strong ion pairs, and the overall stability of a catalytic system is remarkably enhanced through the multiple non-covalent interaction. Compared with traditional acid catalysis or single ionic liquid catalysis, the synergistic catalysis system is high in catalytic activity, excellent in selectivity and high in stability, and the yield and purity of the target product 3-methoxy-N, N-bis (2-ethoxyl) aniline can be remarkably improved.

This invention discloses a synthetic process for 3-chloro-5,5-disubstituted-4,5-dihydroisoxazole. The process comprises the following steps: S1: Under acid catalysis, compound III undergoes a cyclization reaction with hydroxylamine and / or hydroxylamine salt to obtain compound V; S2: In a solvent, compound V undergoes a chlorination reaction with a chlorinating agent to obtain compound VI. This invention provides an economical, environmentally friendly synthetic process that improves the selectivity of 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole, and has significant industrial application value.

The invention belongs to the technical field of oil-based super lubrication, and particularly relates to a construction method of super-lubrication low-viscosity polar polyether modified silicone oil. The preparation method comprises the following steps: reacting allyl polyether with hydrogen-containing silicone oil according to a mass ratio of (70-80): 1 under the catalytic condition of chloroplatinic acid to obtain low-viscosity polar polyether modified silicone oil, and mixing 0.5 wt.%-1.5 wt.% of a polar additive, 0.1 wt.%-0.5 wt.% of surface functionalized nanoparticles and 97.5 wt.%-99.4 wt.% of the low-viscosity polar polyether modified silicone oil according to mass percent to obtain the compound lubricating oil. Performing ultrasonic treatment on the composite lubricating oil, and standing to obtain the super-lubricating low-viscosity polar polyether modified silicone oil. The polar additive molecules and the small-size and easy-to-disperse functional nanoparticles are compounded at the same time, so that the interaction between a lubricating film and a friction surface is remarkably enhanced in a cross-scale manner, and a friction pair motion interface is promoted to form a friction composite film with high bearing and low shearing characteristics; and stable ultralow friction and abrasion under the working conditions of wide rotating speed and wide load are achieved, and theoretical and technical supports are provided for engineering application of the oil-based super-lubrication technology.

The invention relates to cyclotrithio-tri (2-mercaptoethylthio) mercaptan as shown in a formula I and a preparation method and application thereof. A two-step method of thio reaction and nucleophilic substitution is adopted. In the step I, thiourea is used as a sulfur source, epoxy atoms in trioxymethylene are replaced by sulfur atoms one by one under the condition of strong acid, and 1, 3, 5-trithiacyclohexane is generated. In the nucleophilic reaction of acid catalytic activation in the step II, 1, 3, 5-trithioxane and Lewis acid are subjected to coordination complexation firstly, one sulfydryl in dithiol serves as a nucleophilic reagent to attack an electrophilic carbon center of a ring-opening intermediate, a new C-S bond is formed, and a linear intermediate containing sulfydryl is generated; according to the process, three thiol groups are introduced in sequence step by step, and sulfur alkylation substitution is completed. The obtained product has the characteristics of high purity, high light transmittance and large refractive index, and can be used for preparing optical materials with ultrahigh refractive index and high light transmittance.

The invention belongs to the technical field of biomass conversion and functional food ingredients, and discloses a method for preparing galactooligosaccharide prebiotics from cellulose. The method comprises the following steps: mixing cellulose with a galactose aqueous solution, and drying to obtain galactose pre-impregnated cellulose; impregnating the cellulose pre-impregnated with galactose with an acid catalyst solution, and drying to obtain cellulose impregnated with galactose and an acid catalyst; carrying out solvent-free ball milling treatment on the cellulose impregnated with the galactose and the acid catalyst, so that the cellulose is synchronously subjected to depolymerization and grafting reaction with the galactose to obtain a crude product; and carrying out purification treatment on the crude product, and removing the residual acid catalyst to obtain the galactooligosaccharide prebiotics. According to the galactooligosaccharide prepared by the preparation method disclosed by the invention, the water solubility of the oligosaccharide is greatly improved due to the introduction of a galactose branched chain, the yield of a final product is high, and the prebiotic activity of the final product is equivalent to that of a high-cost enzymic method commercial product and even is better for a specific strain.

This invention discloses a room-temperature curing self-cleaning photocatalytic film based on multi-level interface synergistic enhancement and its preparation method. The method includes: (1) preparing monodisperse TiO2 nanocrystals with controllable lattice strain using a non-equilibrium growth method; (2) constructing a TiO2 / UiO-66-NH2 / rGO ternary Z-type heterojunction photocatalytic material; (3) preparing a two-component room-temperature curing all-inorganic binder system composed of acid-catalyzed silica sol (ACSS) and fluorosilane-modified polysilazane; (4) compounding the heterojunction photocatalytic material with the binder system and adding nano-silica dispersion, and forming a coating liquid by ultrasonic-shear synergistic dispersion; (5) depositing it on a glass substrate using a gradient ultrasonic spraying process, and curing it into a film by room temperature-medium temperature stepwise curing. This invention achieves, for the first time, a fully inorganic self-cleaning film with both ultra-high photocatalytic activity and ultra-long weather resistance under room temperature curing conditions through multi-level interface synergy of ternary heterojunction synergistic photocatalytic enhancement, room temperature curing of two-component inorganic binder, and gradient film-forming structure design. It solves the technical problem of the difficulty in unifying photocatalytic activity, film-forming process, optical performance and service life in the prior art.

The application belongs to the technical field of organic chemical synthesis, and particularly relates to a nitrogen center chiral base derivative, a preparation method and application thereof. The preparation method of the nitrogen center chiral base derivative provided by the application can effectively synthesize a base with only a nitrogen chiral center by using a tetrahydrodibenzo-diazocine compound as a raw material and through chiral phosphoric acid catalyzed amination reaction. Moreover, the synthesis method provided by the application has the advantages of high efficiency, simple steps and strong enantioselectivity, is suitable for industrialized production of chiral bases and derivatives thereof, and provides a new approach for research and application of chiral compounds. Meanwhile, the base derivative prepared by the application is a base molecule with a nitrogen center chirality, and has wide application prospects in the fields of molecular recognition, DNA binding, supramolecular chemistry, material science, asymmetric catalysis and drug development.

The application discloses a ginseng stem and leaf composition based on fine extraction, a tablet and a production process, belongs to the technical field of natural medicine preparation, and aims to solve the problems of low utilization rate of ginseng stem and leaf components, complex rare saponin conversion process and poor bioavailability of products in the prior art. The core process comprises the following steps: fine separation of hydrophilic ginseng flavone / ginseng polysaccharide component A and saponin precursor component by adopting enzyme-assisted extraction combined with double-membrane filtration and fractional elution; solid phase thermal conversion of the saponin precursor component into lipophilic conversion component B rich in rare saponins Rg5, Rk1 and Rh4 by using a solid acid catalyst; and further preparation of the lipophilic conversion component B into a solid self-microemulsifying carrier, and compression of the hydrophilic ginseng flavone / ginseng polysaccharide component into a double-layer tablet.

The present application relates to the technical field of chemical essence and flavor, and particularly relates to a decenoic acid ester compound, a preparation method and application thereof, and comprises the following steps: (1) preparing 2-(4-methyl-benzylidene) heptanal: under the condition of an inorganic alkaline reagent, p-methylbenzaldehyde and n-heptanal are subjected to aldol condensation reaction to synthesize 2-(4-methyl-benzylidene) heptanal; (2) preparing 2-(4-methyl-benzylidene) heptyl alcohol: under the condition of a reducing agent, 2-(4-methyl-benzylidene) heptanal is reduced to 2-(4-methyl-benzylidene) heptyl alcohol; (3) preparing 5-decenoic acid 2-(4-methyl-benzylidene) heptyl alcohol ester: under the catalysis of an acid, 5-decenoic acid and 2-(4-methyl-benzylidene) heptyl alcohol are subjected to esterification to synthesize 5-decenoic acid 2-(4-methyl-benzylidene) heptyl alcohol ester. The compound in the present application has jasmine aroma and milk aroma, has elegant aroma, has long-lasting aroma, and has important use in the field of daily chemical flavoring.

The invention discloses a bifunctional group copolymerization separation membrane with a main chain containing crown ether as well as a preparation method and application of the bifunctional group copolymerization separation membrane. According to the method, 2, 2 '-bis (3-sulfonated propoxy) biphenyl disodium and isatin are used as monomers, a bifunctional material with a main chain containing crown ether is prepared through a superacid catalyzed polycondensation reaction under the condition of a certain reaction temperature, and a pure product is obtained through a large amount of water washing; secondly, preparing the prepared sample into a film through a non-solvent phase transfer method. The prepared bifunctional group copolymerization separation membrane material with the main chain containing crown ether shows relatively good ion exchange capacity, permeation selectivity and stability for lithium element in waste liquid, is simple and convenient to operate and controllable in cost, and shows a good application prospect.