778 results about "Sodium borohydrate" patented technology

The invention discloses a cobalt-loaded covalent organic framework material as well as a preparation method and application thereof, and belongs to the technical field of catalyst preparation. The cobalt-loaded covalent organic framework material is prepared by taking a carbonized covalent organic framework as a matrix and cobalt nitrate hexahydrate as a cobalt source, reducing by using a sodium borohydride methanol solution, and introducing transition metal cobalt into the framework through room-temperature impregnation and thermal reduction processes. In the material, active components comprise Co0 and Co < 2 + > which are uniformly distributed on a carrier. Moreover, the metal cobalt is stably loaded in a carbon skeleton through the bonding effect of heteroatoms such as nitrogen and carbon, so that the stability, the catalytic activity and the durability of the metal cobalt are effectively improved, the dissolution risk of the metal cobalt is reduced, the hidden danger of environmental pollution is reduced, and efficient catalytic activity is shown in the aspect of catalyzing and activating peroxymonosulfate to degrade organic pollutants; and good recycling stability is achieved.

The invention relates to the technical field of biomedical treatment, and particularly discloses a biological valve treatment method and a biological valve dry piece. The bioprosthetic valve treatment method provided by the invention comprises the following steps: pretreatment, crosslinking, degreasing, anti-calcification and drying. In the anti-calcification step, an anti-calcification solution is used for treatment; the anti-calcification solution is a 0.08 to 0.12 M PBS (Phosphate Buffer Solution) containing 0.5 to 6 weight percent of ethanolamine and 0.1 to 0.5 weight percent of sodium borohydride; furthermore, the anti-calcification solution is a 0.08 to 0.12 M PBS (Phosphate Buffer Solution) containing 2 to 4 weight percent of ethanolamine and 0.2 to 0.4 weight percent of sodium borohydride; the invention further provides the bioprosthetic valve dry piece obtained through the bioprosthetic valve processing method. According to the bioprosthetic valve treatment method, the anti-calcification performance of the bioprosthetic valve can be improved, and the obtained bioprosthetic valve dry piece has good stability and storage performance.

The invention relates to an iron oxide homogeneous and heterogeneous photoelectric self-Fenton electrode material as well as a preparation method and application thereof, the self-Fenton electrode material comprises a carbon fiber cloth matrix and an active alpha / beta-Fe2O3 homojunction grown on the carbon fiber cloth in situ, and the structure of the self-Fenton electrode material is shown as alpha / beta-Fe2O3 / CC. The alpha / beta-Fe2O3 homojunction is formed by compounding two phases, namely, alpha-Fe2O3 and beta-Fe2O3. And the alpha / beta-Fe2O3 / CC has an oxygen vacancy. The preparation method comprises the following steps: soaking a pretreated carbon fiber cloth substrate in an alpha / beta-Fe2O3 precursor solution prepared in advance for reaction, and after the reaction is finished, carrying out post-treatment to obtain FeOOH / CC; calcining the FeOOH / CC, and cooling to obtain alpha / beta-Fe2O3 / CC; the alpha / beta-Fe2O3 / CC can introduce oxygen vacancies through reduction activation treatment of a sodium borohydride aqueous solution. Compared with the prior art, H2O2 can be generated in situ, sustainable circulation from Fe < 3 + > to Fe < 2 + > is enhanced, generation of hydroxyl radicals in the self-Fenton reaction is promoted, and the degradation reaction speed and efficiency of organic pollutants, especially antibiotics are greatly improved.

The invention relates to a metallized microbubble and a preparation method thereof, a construction method of a multifunctional composite probe, and a rapid bacterium capturing and sterilizing method, and belongs to the technical field of functional material preparation. The method aims at solving the technical problems that in the prior art, a metal coating on the surface of the hollow glass microbubble is not uniform, combination is not firm, and stability is poor. According to the technical scheme, the method is characterized by comprising the following steps: mixing surface-activated hollow glass microbubbles with a polyethyleneimine solution for reaction, and washing and drying to obtain polyethyleneimine-coated hollow glass microbubbles; then reacting with a single-stranded DNA buffer solution to obtain an intermediate product loaded with DNA; then introducing a silver nitrate solution to load silver ions on the surface of the compound; and finally, reducing through a sodium borohydride solution to prepare the metallized microbubbles. The metalized microbubbles prepared by the method can be used for constructing a multifunctional composite probe to realize efficient capture and synergistic antibiosis of targets such as bacteria.

The invention belongs to the technical field of nano composite materials, and discloses a novel transition metal-inserted transition metal sulfide composite rare earth oxide photocatalytic material with a solid mediator Z-type heterostructure, and a preparation method and application of the novel transition metal-inserted transition metal sulfide composite rare earth oxide photocatalytic material. The preparation method comprises the following steps: mixing transition metal salt, thioacetamide, nitrate hexahydrate and water to obtain a mixed solution 1; mixing the mixed solution 1 with a hydrazine hydrate solution, and performing hydrothermal reaction to obtain a mixed solution 2; mixing the mixed solution 2 with ammonia water, and sequentially carrying out hydrothermal reaction, drying and calcining to obtain a calcined product; and mixing the calcined product with a sodium borohydride aqueous solution, and drying to obtain the photocatalytic material. The obtained photocatalytic material of the transition metal inserted transition metal sulfide composite rare earth oxide with the solid mediator Z-type body heterostructure has the characteristics of high stability, safe interface contact and rapid charge migration.

The invention relates to the technical field of electro-catalysis materials, and discloses an iron-doped copper oxide catalyst, a preparation method thereof and application of the iron-doped copper oxide catalyst in electro-catalysis of nitrate to synthesize ammonia. The method comprises the steps that CuCl2 serves as a metal precursor, ascorbic acid serves as a reducing agent, and Cu2O nanoparticles are obtained through a hydrothermal precipitation method; then, Cu2O is added into a solution containing FeSO4, sodium borohydride is added, centrifugal washing and drying are carried out, and the iron-doped copper oxide nitrate electroreduction catalyst which is rich in defects and uniform in metal dispersion is obtained through a programmed heating pyrolysis reduction method. The electro-catalytic material obtained by adopting the method disclosed by the invention has a relatively large catalytic active area and relatively abundant defect sites and oxygen vacancies, the nitrate adsorption and activation effects are improved, the supply of active hydrogen is promoted by constructing stable heterogeneous active sites, the product selectivity and Faraday efficiency in NO3RR are improved, and the electro-catalytic material has good durability.

The invention provides a GelMA microneedle patch loaded with chromogenic gold nano bipyramids and a preparation method thereof.The method comprises the steps that citric acid, chloroauric acid and a CTAC solution are mixed, then sodium borohydride is added, and a seed solution is obtained through stirring and standing; mixing chloroauric acid, silver nitrate, hydrochloric acid and CTAB (cetyltrimethyl ammonium bromide), and sequentially adding ascorbic acid and the seed solution to obtain a growth solution; carrying out centrifugation, morphology regulation and chemical etching purification to obtain a chromogenic gold nano bipyramid solution; the preparation method comprises the following steps: reacting gelatin with methacrylic anhydride in PBS, dialyzing and freeze-drying to obtain GelMA; dissolving GelMA in the gold nanoparticle bipyramid solution, and adding a photoinitiator LAP to obtain a mixed precursor solution; and the GelMA microneedle patch loaded with the gold nano bipyramid is prepared through mold casting, centrifugation, ultraviolet light crosslinking and drying demolding. The microneedle extraction and gold nano bipyramid color development integrated scheme is initiated, blood sampling is not needed, the dermis interstitial fluid is extracted in a minimally invasive mode through the microneedle, detection pain and trauma are reduced, the cross infection risk of blood treatment is avoided, and the microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle microneedle

The invention discloses a method for rapidly determining the content of breast milk oligosaccharide in dairy products, which comprises the following steps: sampling and pretreating different types of dairy products according to sample states, carrying out ultrasonic extraction, refrigerated centrifugal degreasing and centrifugal ultrafiltration protein purification on the obtained sample, and reducing the purified sample solution by using sodium borohydride to obtain a sample solution to be detected; reducing the breast milk oligosaccharide standard substance by sodium borohydride to obtain a standard solution to be detected; determining the standard substance solution and the to-be-detected sample solution by adopting ultra-high performance liquid chromatography-tandem mass spectrometry, establishing a standard curve, and carrying out quantitative analysis on the to-be-detected sample solution; the chromatographic conditions are as follows: an ACQUITY UPLC BEH Amide hydrophilic interaction chromatographic column is adopted; the mobile phase A is 20 mmol / L ammonium formate; the mobile phase B is acetonitrile; and gradient elution.

The preparation method comprises the following steps: (1) fish skin pretreatment: (2) gas foaming treatment: weighing sodium borohydride with a certain molar concentration, dissolving the sodium borohydride in a phosphate buffer solution with a certain concentration, stirring until bubbles in the solution are obviously generated and most of solids are dissolved, and then, carrying out gas foaming treatment; putting the cleaned fish skin tissues in the step (2), and performing foaming treatment; (3) cleaning treatment; and (4) protection and storage. The gas foaming technology is innovatively adopted for decellularization treatment, the interface stripping effect between cells and a matrix is remarkably enhanced on the premise that the collagen three-dimensional structure and the scaffold morphology integrity are not damaged, and the method is suitable for the decellularization pretreatment process of soft tissue (such as fish skin and placenta) with a compact structure or cell-intensive type. The development of a biomedical material, especially a tissue engineering scaffold technology, is promoted, and the preparation method has a wide application prospect.

The invention belongs to the field of photocatalytic preparation of hydrogen peroxide, and relates to a novel secondary amine linked covalent organic framework material (AR-COF) as well as a preparation method and application thereof. According to the material, tetraaldehyde phenyl porphyrin and 2, 5-diamino-1, 4-benzenediol dihydrochloride are subjected to a Schiff base reaction to synthesize an imine bond connected porphyrinyl covalent organic framework (IM-COF), and then synthesis post-modification (PSM) is performed on the imine bond connected porphyrinyl covalent organic framework (IM-COF) so that the imine bond connected porphyrinyl covalent organic framework (IM-COF) and sodium borohydride can be subjected to a reduction reaction to generate AR-COF. The photocatalytic stability of the material is maintained through modification after synthesis, the catalytic activity is improved, and the original crystal structure is not damaged. A photocatalytic hydrogen peroxide production experiment shows that the catalytic activity of AR-COF under 420 nm monochromatic light is superior to that of IM-COF, the yield under an oxygen condition reaches 7.79 mmol.g <-1 >. H <-1 >, and hydrogen peroxide can be stably produced. The method utilizes solar energy for green synthesis under mild conditions, and provides a safe and efficient method for hydrogen peroxide production.

The invention discloses a preparation method of platinum-based multi-metal aerogel and application of the platinum-based multi-metal aerogel in an electro-catalysis hydrogen evolution reaction. The method comprises the following steps: firstly, sequentially adding platinum salt and other metal salts into pure water, uniformly mixing, then adding a sodium borohydride solution, uniformly mixing, quickly freezing the reaction solution with liquid nitrogen, melting to obtain wet gel, and then washing and drying the wet gel to obtain the aerogel. The obtained metal aerogel is applied to a hydrogen evolution electrocatalyst and shows excellent catalytic activity under an alkaline condition. The preparation method has the advantages that the synthesis process is simple, convenient and efficient, regulation and optimization of an electronic structure can be realized through interaction among multiple metals, so that the catalytic performance is improved, the porous structure of the aerogel effectively provides a high-speed mass transfer channel, the catalytic activity is improved, and the preparation method is suitable for industrial production. And a solid foundation is laid for wide application of the metal aerogel material in the field of industrial chemical engineering.

The invention discloses a modified microfiltration membrane for enriching biological particles and a preparation method and application thereof, and belongs to the technical field of biological separation.The preparation method of the modified microfiltration membrane comprises the following steps that a mixed cellulose ester microfiltration membrane is provided and subjected to alkali liquor activating treatment; placing the activated membrane in a weakly alkaline buffer solution for balancing; the preparation method comprises the following steps: in a weakly alkaline buffer solution, firstly contacting the surface of the membrane with a tannic acid solution to carry out a first reaction, and then directly adding a polyethyleneimine solution to carry out a second reaction under the condition of not replacing a system, so as to form a phenol-amine cross-linked network on the surface of the membrane in situ; sodium cyanoborohydride is continuously added for reduction stabilization treatment, and the modified microporous filter membrane is obtained. The modified microporous filter membrane prepared by modifying the microporous filter membrane with tannic acid and polyethyleneimine can realize one-step synchronous enrichment of all negatively charged targets, and the problems of target loss, efficiency loss and the like caused by a multi-step process are avoided from the source.

The present invention discloses a nano copper-based catalyst, its preparation method, and its application in the electrocatalytic reduction of carbon dioxide and carbon monoxide. Copper chloride (or copper nitrate, copper acetate) is dissolved in ultrapure water, and a sodium borohydride solution is added dropwise. Stir at room temperature for 5-60 min, filter, and dry to obtain a nano copper catalyst. Further, through a displacement reaction, nano copper-palladium and copper-silver catalysts are obtained. The present invention is applied to the electrocatalytic reduction of carbon monoxide. In a membrane electrode assembly (MEA) electrolyzer, the Faraday efficiency of multi-carbon products (C2+) reaches up to 95%, the partial current density reaches up to 3 A cm-2, and the overall electrolyzer energy efficiency reaches up to 39%. It can stably electrolyze for 30 hours at 1 A cm-2. This nano copper catalyst is applied to the electrocatalytic reduction of carbon dioxide. In an MEA electrolyzer, the Faraday efficiency of C2+ reaches up to 66%, and the partial current density reaches up to 331 mA cm-2.

The invention provides a method for removing nitrate in water by using a modified zero-valent iron aerogel electrocatalyst, which comprises the following steps: preparing a mixed solution of ferrous sulfate and sodium sulfide, preparing a sodium borohydride solution, mixing and magnetically stirring the mixed solution and the sodium borohydride solution to obtain black colloid, and finally obtaining vulcanized zero-valent iron aerogel, dispersing the obtained sulfurized zero-valent iron aerogel and a Nafion solution in absolute ethyl alcohol to prepare a catalyst mixed solution; potassium nitrate and potassium hydroxide are dissolved in a pure water solution to serve as electrolyte, a sulfurized zero-valent iron aerogel electrode is used as a cathode, a platinum sheet is used as an anode, a mercuric oxide electrode is used as a reference electrode, and an electrocatalytic reduction reaction is carried out by using a three-electrode system. The technology not only can improve the efficiency of water nitrate pollution treatment, but also conforms to the concept of green and low-carbon development, and has a wide environment application prospect.

The application provides a kind of superfine copper powder and its preparation method and application, the preparation method of the above-mentioned superfine copper powder uses two-step liquid phase reduction method to prepare superfine copper powder, and improves process conditions, using dropwise feeding mode. Among them, the first step uses alkaline ascorbic acid solution to reduce copper chloride to cuprous chloride with narrow particle size distribution; the second step uses ferrous sulfate and sodium citrate as mixed reducing agent, and sodium citrate can also be used as a complexing agent, which helps to reduce the cuprous chloride to spherical, well-dispersed, uniform particle size distribution of superfine copper powder. At the same time, the raw materials used by the application are easy to obtain, the reaction process is mild, and organic solvents and toxic and hazardous reagents such as sodium borohydride and hydrazine hydrate are not needed, the preparation process has cost effectiveness, is friendly to the environment, and is suitable for industrial production.

The invention discloses a fluorine coating melt-extruded on the surface of a polyimide film and a preparation method of the fluorine coating, and relates to the technical field of coating materials. The fluorine coating melt-extruded on the surface of the polyimide film is prepared by melt-mixing a component A, a component B and a fluorine-containing polymer, melt-extruding and coating the mixture on the surface of the polyimide film, the component A is a hydroxyl mixture, and the component B is an end-capped prepolymer; the hydroxyl mixture comprises hydroxyl terpyridine and hydroxyl fluorocarbon resin, the hydroxyl terpyridine is prepared by reacting diacetylpyridine with 3, 4-dihydroxyethoxy benzaldehyde, the 3, 4-dihydroxyethoxy benzaldehyde is prepared by reacting 3, 4-dihydroxybenzaldehyde with 2-chloroethanol, and the hydroxyl fluorocarbon resin is prepared by reacting 3, 4-dihydroxybenzaldehyde with 2-chloroethanol. The hydroxyl fluorocarbon resin is prepared by reacting butyl acrylate, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, methacrylic acid and 2-hydroxyethyl methacrylate; the fluorine-containing polymer is prepared by carrying out a reaction on p-aminobiphenyl, 2, 3, 5, 6-tetrafluoroterephthalaldehyde and sodium triacetoxyborohydride, and the p-aminobiphenyl is prepared by carrying out a reaction on decafluorobiphenyl and 4-aminophenol; and the water resistance of the polyimide film coated with the fluorine coating is ensured.

The invention discloses a nitrogen / boron-doped non-noble metal-based material, a synthesis method thereof and application of the nitrogen / boron-doped non-noble metal-based material in a microbial fuel cell. According to the method, a carbon fiber brush is used as a substrate, urea and sodium borohydride are used as a nitrogen source and a carbon source respectively, and the nitrogen / boron doped non-noble metal-based material is synthesized through a hydrothermal method. The electrostatic interaction between graphene oxide and FeCoNi-LDH is utilized to realize tight combination, so that FeCoNi-LDH nanosheets are uniformly dispersed on the surface of the carbon fiber brush, and the problems that LDHs are easy to agglomerate and poor in conductivity are solved; in the boron / nitrogen co-doping process, an efficient electron transmission channel is constructed by adjusting the electronic structure of the composite material, and the material is endowed with excellent electron transmission capability and oxygen reduction performance. In an MFC (Microbial Fuel Cell) test constructed by taking a nitrogen / boron-doped non-noble metal-based material as a cathode, the output voltage and the maximum power density are several times of those of commercial Pt / C and a blank carbon fiber brush, and the carbon fiber brush has a wide application prospect in the field of microbial fuel cells.

The invention belongs to the field of gas sensors, and discloses an indium oxide composite material based on palladium doping and a preparation method and application thereof.The preparation method comprises the steps that indium nitrate, absolute ethyl alcohol, ammonia water and deionized water are used for preparing an indium oxide material, then palladium ions are doped in an indium oxide solution to obtain a palladium ion-doped indium oxide solution, and the palladium ion-doped indium oxide solution is subjected to vacuum drying to obtain the palladium ion-doped indium oxide composite material. And reducing and centrifuging by using sodium borohydride to obtain a palladium-doped indium oxide composite material, and then preparing the palladium-doped indium oxide composite material into the gas sensor. The key technological process design of the preparation method is improved, so that the problems that the reaction of a pure indium oxide gas sensor needs relatively high activation energy and the surface of a pure semiconductor lacks selectivity to sulfide can be effectively solved, and the detection of dimethyl disulfide gas is realized.

The invention relates to the technical field of chemical intermediates, and particularly discloses a preparation method of a givelastat intermediate.According to the preparation method, an initiator compound 5 can be synthesized by adopting cheap 2-hydroxy-6-naphthoic acid (CAS: 16712-64-4, 141 yuan / kg), and the preparation method is different from a method in the prior art. A gemvelastat intermediate compound 4 is synthesized from a compound 5 through a three-step reaction, compared with the prior art, the yield is high, industrial amplification production is more facilitated, in the process of synthesizing a compound 6 from the compound 5, acetonitrile can be adopted as a cyanide source in a reaction system, activated hydroxyl is subjected to a coupling reaction, and the yield is high. In the process of synthesizing a compound 6 from a compound 7 instead of a traditional metal cyanide, or in the process of synthesizing a compound 6 from another compound 5, a cheap cuprous cyanide and cuprous iodide system is adopted for a coupling reaction, and in the process of synthesizing a compound 4 from a compound 7, an acetic acid and sodium triacetoxyborohydride reaction system is adopted, so that the compound 6 is synthesized. And the important intermediate of the givelastat can be obtained with high yield.

The invention discloses a method for detecting aflatoxin B1 in coffee based on colorimetric and photo-thermal dual modes of MXene (at) Pt nano-enzyme, which comprises the following steps: etching Ti3AlC2 by using LiF and HCl to obtain MXene, synthesizing platinum nano-particle modified MXene nano-enzyme (MXene (at) Pt) by using dopamine carbon dots and sodium borohydride as reducing agents and adopting an in-situ reduction technology, and detecting aflatoxin B1 in coffee by using the MXene (at) Pt nano-enzyme (MXene (at) Pt nano-enzyme (MXene (at) Pt nano-enzyme (MXene (at) Pt nano-enzyme (MXene (at) Pt). The MXene (at) Pt shows near-infrared light stimulation enhanced peroxidase-like activity and photo-thermal performance and can catalyze blue deepening and temperature rising of a substrate 3, 3 ', 5, 5'-tetramethyl benzidine (TMB), when aflatoxin B1 exists, POD-like activity of MXene (at) Pt nano-enzyme is inhibited, and colorimetric and temperature signals are reduced; a method for detecting the AFB1 by the colorimetric temperature dual-mode sensor is established, and the method has the characteristics of high sensitivity, strong specificity, simplicity and rapidness in operation and the like.

The invention relates to the technical field of energy environment science and engineering, in particular to a plasma-ferroelectric WO3-x / K4Nb6O17 heterojunction and a preparation method and application thereof. According to the plasma-ferroelectric WO3-x / K4Nb6O17 heterojunction, a ferroelectric K4Nb6O17 nanosheet serves as a substrate, oxalic acid dihydrate and sodium borohydride serve as composite reducing agents, in-situ synthesis of WO3-x nanoparticles with oxygen vacancies and in-situ loading and growth of the WO3-x nanoparticles on the surface of the K4Nb6O17 nanosheet are achieved in the solvent heat treatment process, and the plasma-ferroelectric WO3-x / K4Nb6O17 heterojunction is obtained. Therefore, the plasma-ferroelectric WO3-x / K4Nb6O17 heterojunction is obtained. The WO3-x / K4Nb6O17 heterojunction can be used as a photocatalyst, and the coupling reaction efficiency of preparing CO through photocatalytic CO2 reduction and preparing hydrogenated benzoin through benzyl alcohol oxidation is improved.

The invention discloses a liquid metal-based catalyst with flowable amorphous cobalt active sites as well as a preparation method and application of the liquid metal-based catalyst. The spherical gallium-based liquid metal loaded amorphous cobalt nanosheet material is synthesized by using a sodium borohydride ice bath method. Due to the optimization of the synthesis process, the amorphous cobalt nanosheets are uniformly distributed on the surfaces of the liquid gallium balls, are small in size, are high in utilization rate and are not easy to agglomerate; the intrinsic flow characteristic of the liquid metal gallium realizes the efficient reverse hydrogen overflow effect, optimizes the formation process of a catalytic reaction intermediate, and accelerates the formation of the intermediate. The composite material has the advantages of low overpotential, high Faraday efficiency, high ammonia production rate, good stability and the like during nitrate electrocatalytic reduction reaction, meets the requirements of production and use, and is low in preparation cost.

The invention discloses a seawater initiation preparation method of metal wet gel and aerogel and application of the seawater initiation preparation method in electro-catalysis ethylene glycol oxidation. Comprising the following steps: 1) sequentially adding a metal salt, sodium citrate and a reducing agent into pure water, 2) adding seawater into a reaction solution to obtain wet gel, and 3) washing and drying the wet gel to obtain the aerogel. Seawater can be used for replacing expensive drugs used in a large amount in a salting-out method and an excessive sodium borohydride method, so that the metal nanoparticle solution is unstable, the metal aerogel material is prepared, and the preparation cost of the metal aerogel is greatly reduced. The metal aerogel obtained by the invention shows excellent catalytic performance in the application of electro-catalysis of ethylene glycol oxidation.

A method for hydrogen (H2) generation includes contacting a graphite-phase carbon nitride cobalt oxide and magnesium aluminum oxide nanocomposite (g-C3N4@CoO / MgAl2O4) with sodium borohydride (NaBH4) in water (H2O) and hydrolyzing the sodium borohydride to generate hydrogen. The g-C3N4@CoO / MgAl2O4 nanocomposite comprises a graphite-phase carbon nitride (g-C3N4) in an amount of 5 to 15 percent by weight (wt. %), cobalt oxide in an amount of 1 to 10 wt. %, and magnesium aluminum oxide (MgAl2O4) in an amount of 75 to 95 wt. % based on a total weight of the g-C3N4@CoO / MgAl2O4 nanocomposite.

The invention discloses a divalent nucleic acid aptamer fluorescence detection method based on an exonuclease I auxiliary target circulation strategy, and belongs to the field of analysis and detection.The divalent nucleic acid aptamer is a repetitive sequence composed of two monovalent nucleic acid aptamers and can form double-stranded DNA through base complementary pairing with complementary strand cDNA of the divalent nucleic acid aptamer, and the divalent nucleic acid aptamer can be used for fluorescence detection of the divalent nucleic acid aptamer. The method comprises the following steps: taking a bivalent nucleic acid aptamer as a template, forming a DNA silver nanocluster (DNA-AgNCs) under the action of silver nitrate and sodium borohydride, and when the target okadaic acid exists, combining the bivalent nucleic acid aptamer with the target, so that cDNA can be replaced from double-stranded DNA by the target. Exonuclease I is added to perform enzyme digestion on the cDNA and the divalent nucleic acid aptamer, so that the fluorescence intensity of the DNA-AgNCs can be rapidly reduced. The content of the okadaic acid can be judged by detecting the change of the fluorescence intensity. The invention provides a simple, convenient, rapid, high-sensitivity and high-specificity detection method for okadaic acid detection based on a divalent nucleic acid aptamer for the first time.

The present invention provides a paroxysmal hemoglobinuria indication drug ipropam key intermediate synthesis method, and relates to the technical field of ipropam, the method comprises: taking p-bromobenzaldehyde as an initial raw material, adopting an S-configuration catalyst to obtain an intermediate 03, carrying out protection group removal on the intermediate 03, carrying out automatic ring closing to obtain an intermediate 04, and carrying out post-treatment to obtain the paroxysmal hemoglobinuria indication drug ipropam key intermediate. Reducing the intermediate 04 with sodium borohydride to obtain a single cis-configuration intermediate 05, then carrying out a chiral flip reaction and hydrolysis to remove p-nitrobenzoic acid, then carrying out an etherification reaction with diethyl sulfate to obtain an intermediate 08, reducing amide of the intermediate 08 with sodium borohydride and boron trifluoride diethyl etherate to obtain an intermediate 09, then carrying out an acetylation reaction to protect amino, and finally carrying out a reaction to obtain the chiral cis-configuration intermediate 03. Cuprous cyanide is subjected to a cyanation reaction and a hydrolytic esterification reaction to obtain the ipropam key intermediate TM. The method is low in raw material price, high in chiral control selectivity, easy in reaction condition control and low in equipment requirement, avoids column chromatography and other operations, and is more suitable for industrial production.

The preparation method comprises the following steps: adding MnO2 into deionized water, carrying out uniform ultrasonic dispersion, adding RuCl3.xH2O, carrying out uniform ultrasonic dispersion, slowly dropwise adding an excessive amount of a sodium borohydride aqueous solution into the dispersed solution under vigorous stirring, continuously carrying out a stirring reaction for 3-5 h after the dropwise addition is completed, and after the reaction is completed, carrying out filtration, washing and drying to obtain the Ru / Mn3O4-x hydrogen evolution electrocatalyst. And centrifuging and collecting solids, sequentially washing and drying, fully grinding the obtained sample, transferring to an inert gas atmosphere at 300-500 DEG C, and calcining for 1-2 hours to obtain the Ru / Mn3O4-x hydrogen evolution electrocatalyst. The Ru / Mn3O4-x hydrogen evolution electrocatalyst prepared by a wet chemical reduction method has good intrinsic activity and good electrochemical performance, the process is simple, the cost is low, and a new thought is provided for reasonably constructing a ruthenium-based electrocatalyst to improve the electrocatalytic activity.

The invention relates to the technical field of chemical synthesis, and discloses a method for preparing 2, 5-furandicarboxylic acid, which comprises the following steps: dispersing cobalt nitrate and nickel sulfate into an aqueous solution of polyvinylpyrrolidone at room temperature; adding a sodium borohydride solution to obtain nano colloid; preparing an aqueous suspension of cerium oxide, and adding the aqueous suspension into the nano colloid; centrifugally filtering, and recovering a solid product; washing the solid product; centrifuging, putting solid powder obtained after centrifuging into a drying oven, and drying; and calcining and grinding the solid powder to finally prepare the Co-Ni / CeO2 catalyst. And dissolving 5-hydroxymethylfurfural in water at normal temperature, adding the prepared Co-Ni / CeO2 catalyst and a sodium hypochlorite solution, reacting, and filtering to remove the catalyst, thereby obtaining the 2, 5-furandicarboxylic acid. The method disclosed by the invention has the advantages of no use of strong base, low reaction temperature, short reaction time, few byproducts, greenness and sustainability.

The invention relates to the technical field of medicines, in particular to a preparation method of calcium L-5-methyltetrahydrofolate. According to the method, N-(4-aminobenzoyl)-L-glutamic acid, 2, 4, 5-triamino-6-hydroxypyrimidine sulfate and propane trihalide are adopted as starting raw materials, and tetrahydrofolic acid is synthesized through a one-pot method; compared with synthesis of L-5-methyl calcium tetrahydrofolate by using high-purity folic acid as an initial raw material, the process route does not involve use of chemical reagents such as sodium borohydride, zinc powder and some noble metal catalysts any more, the reaction is easier to control, the cost is lower, the safety is higher, the method is more environmentally friendly, and industrial production is easier to carry out.

The invention discloses a microbial soil conditioner and a preparation method thereof, and relates to the technical field of soil improvement. The method comprises the following steps: culturing heavy metal-resistant chlorella and aspergillus niger to obtain a mixed bacterial suspension, combining the mixed bacterial suspension with a composite chelating modifier prepared by reacting chitosan quaternary ammonium salt, ethylenediamine tetraacetic acid and epichlorohydrin, carrying out crosslinking by using genipin to obtain a functional microbial agent, and carrying out pyrolysis and acid oxidation on corn straws as a raw material to obtain the heavy metal-resistant chlorella modified functional microbial agent. The preparation method comprises the following steps: preparing a nano zero-valent iron-biochar composite material, reducing and loading ferrous ions through sodium borohydride, preparing the nano zero-valent iron-biochar composite material, mixing the nano zero-valent iron-biochar composite material with zeolite, bentonite and a silane coupling agent, carrying out spray drying to prepare a porous carrier substance, and finally stirring and mixing an organic fertilizer complex microbial inoculant, the functional microbial inoculant and the carrier substance, and aging to prepare the soil conditioner. The prepared conditioner has a good remediation effect on soil heavy metal pollution.