793 results about "Buffer solution" patented technology

The invention relates to the technical field of sewage treatment, in particular to an electrostatic spinning PVDF nanofiber membrane for sewage treatment and a preparation method and application of the electrostatic spinning PVDF nanofiber membrane. The preparation method comprises the following steps: dissolving PVDF (Polyvinylidene Fluoride) particles in a mixed solvent of DMF (Dimethyl Formamide) and acetone, adding nano TiO2 particles subjected to APTES (Aminopropyltriethoxysilane) surface modification, and adding PVP (Polyvinyl Pyrrolidone) into the solution to obtain a uniform spinning solution; spinning by adopting electrostatic spinning equipment to obtain a PVDF / TiO2 / PVP nanofiber membrane; the nanofiber membrane is soaked in a sodium hydroxide solution, then the membrane is soaked in a Tris-HCl buffer solution containing dopamine, and the final electrostatic spinning PVDF nanofiber membrane is obtained. The average diameter of nanofibers of the nanofiber membrane is 200-300nm, the porosity of the membrane is 70-80%, and the water contact angle is less than 60 degrees; when the nanofiber membrane is used for treating sewage containing organic pollutants and heavy metal ions, the removal rate of the nanofiber membrane on methyl orange can reach 95% or above; the rejection rate of copper ions can reach 90% or above; the removal efficiency of organic pollutants and heavy metal ions is obviously 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 discloses a reaction buffer solution for improving endotoxin detection sensitivity of a recombinant tachypleus amebocyte lysate, a kit containing the reaction buffer solution and application of the reaction buffer solution. The reaction buffer solution comprises the following components: a Tris-HCl buffer solution, magnesium ions, sodium chloride, cane sugar, ethylene glycol diethyl ether diamine tetraacetic acid, a nonionic surfactant and cyclodextrin or a derivative thereof. The invention also discloses a preparation method of the reaction buffer solution and a kit containing the reaction buffer solution. When the reaction buffer solution or the kit is used for detecting the endotoxin of the recombinant tachypleus amebocyte lysate, the sensitivity of the recombinant tachypleus amebocyte lysate for detecting the endotoxin can be improved by one order of magnitude, the lowest detection limit can reach 0.0005 EU / ml, the reaction buffer solution or the kit has strong anti-interference capability and short reaction time, and the detection efficiency is greatly improved.

The application discloses a preparation method of a hydrophilic oil-water separation anti-pollution membrane and the anti-pollution membrane and application thereof, and prepares MNRs material; the MNRs material is dispersed in dimethylacetamide, is uniformly stirred, polyvinylpyrrolidone is added, and stirring is continued, and a first mixture is obtained through ultrasonic treatment; the first mixture is mixed with polyvinylidene fluoride to obtain a second mixture, and the second mixture is stirred; the treated second mixture is dip-coated on a carrier, the dip-coated carrier is treated in deionized water to obtain an ultrafiltration membrane; the ultrafiltration membrane is soaked in a tea polyphenol solution with a Tris-HCl buffer solution, and is shaken to obtain the hydrophilic oil-water separation anti-pollution membrane. The hydrophilic oil-water separation anti-pollution membrane has excellent separation efficiency and flux recovery rate for four different oil-water mixtures of kerosene, gasoline, edible oil and n-hexane. The preparation process of the oil-water separation membrane is simple, the cost is low, and the reaction condition is mild; when the oil-water separation membrane is applied to organic wastewater separation, the oil-water separation membrane has the advantages of high efficiency, good removal performance and good recycling performance.

The invention discloses a method for separating an egg white polypeptide chain by adopting a coupling membrane, and particularly relates to the field of egg white polypeptide chains, the method comprises the following steps: S1, mixing fresh egg white with a buffer solution, adjusting the initial acid-base environment and initial temperature of a system, and measuring key basic parameters after dispersion treatment; s3, introducing the pretreated egg white liquid into a first-stage membrane assembly, monitoring separation process parameters, obtaining interception efficiency, dynamically adjusting operation parameters, and enabling permeate liquid to enter a second-stage membrane assembly; s7, monitoring system environment parameters and polypeptide activity, obtaining an activity retention rate, dynamically adjusting supply parameters, and maintaining the polypeptide activity; s8, classifying and collecting products according to molecular weight intervals, evaluating comprehensive separation efficiency, completing separation and verifying product indexes; by constructing an ultrafiltration membrane-nanofiltration membrane-reverse osmosis membrane three-stage coupling separation system and combining a dynamic parameter adjustment mechanism based on interception efficiency, separation selectivity and refined purity, the purity and separation efficiency of a polypeptide product are remarkably improved.

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 invention belongs to the technical field of water treatment, and particularly relates to a preparation method and application of a PDA / CS composite adsorbent loaded with a bimetallic system, and the preparation method comprises the following steps: 1) dissolving dopamine in a Tris buffer solution to prepare a dopamine prepolymer solution; then adding FeCl3, and carrying out constant-temperature water bath; centrifuging the obtained black suspension, performing suction filtration, washing, collecting a filter cake, and performing freeze drying to obtain PDA microspheres; 2) dispersing PDA microspheres in deionized water, and carrying out ultrasonic treatment until the PDA microspheres are uniformly dispersed; 3) dissolving chitosan in an acetic acid solution, and adding CuCl2 to prepare a mixed solution; the suspension obtained in the step 2 is dropwise added into a mixed solution for constant-temperature water bath, the pH of the mixed solution is adjusted through a NaOH solution, glutaraldehyde is added for constant-temperature water bath after constant-temperature water bath, and 4, the obtained suspension is subjected to centrifugation, suction filtration, washing, filter cake collection and freeze drying.

The invention provides a preparation method and application of a high-activity salmon salmon sperm PDRN (DNA sodium) raw material. The preparation method comprises the following steps: crushing and freezing a salmon testis at an ultralow temperature, adding a mixed solution of a Tris-HCl buffer solution and sodium chloride, and dispersing at a low temperature; adding a compound enzyme preparation with the total enzyme activity of more than or equal to 350KU / L, and carrying out low-temperature appropriate pH enzymolysis; and adjusting the pH value to a suitable range, and carrying out frequency conversion ultrasonic and high-pressure homogenization alternate synergistic treatment in an ice-water bath to obtain the DNA fragmentation liquid, so that the defects of low PDRN activity retention rate, insufficient purity and high protein residue in the prior art are overcome.

The invention belongs to the technical field of medicines, and particularly relates to a hydrogel dressing for promoting healing of diabetic wounds as well as a preparation method and application of the hydrogel dressing. According to the hydrogel dressing for promoting healing of the diabetic wound, glycyrrhizic acid and S-allyl-L-cysteine are used as raw materials, a buffer solution is used as a dispersion medium, and the glycyrrhizic acid and S-allyl-L-cysteine are compounded and self-assembled by controlling the mass ratio of the raw materials, the reaction temperature, the reaction time and the pH value. The hydrogel shows tissue-like viscoelasticity characteristics, can adaptively deform along with wound movement, provides continuous protection for chronic wounds under dynamic physiological conditions, and has flexibility of adapting to dynamic requirements in different healing stages.

The invention provides synthesis of a T-2 toxin antigen and preparation and application of a monoclonal antibody. Relates to the technical field of biotoxin detection. The preparation method of the T-2 toxin antigen comprises the following steps: step 1, synthesizing an immunogen T-2-BSA by adopting a carbodiimide method, dissolving 2mg of T-2 adipic acid with 0.5 mL of dimethylformamide, and recording as a solution A; 5 mg of bovine serum albumin and 3 mg of EDC are dissolved with a 2-morpholine ethanesulfonic acid buffer solution with the pH being 5.5, and the solution is marked as a solution B; step 2, under the condition of stirring, dropwise adding the solution A into the solution B, stirring for 18 hours in a dark place at 4 DEG C, then dialyzing for 3 days by using a phosphate buffer solution, changing the solution once a day, centrifuging the dialysate for 10 minutes at 3,500 r / min, and discarding the precipitate; the adipic acid is coupled with the T-2 toxin through a chemical method, and the unique step enriches the structural characteristics of the hapten, so that the prepared T-2 toxin complete antigen is excellent in immune effect, can efficiently excite immune response of an organism, and shows high specificity and sensitivity.

The invention discloses a composition with a sleep improving function as well as a preparation method and application thereof, and the composition is prepared from the following raw materials in parts by weight: 50-100 parts of acanthopanax root, 30-50 parts of lotus seed, 50-100 parts of spina date seed, 30 parts of lily, 30 parts of longan, 30-50 parts of poria cocos, 30 parts of radix ophiopogonis, 10-30 parts of rehmannia, 10-30 parts of gastrodia elata, 2 parts of glutamic acid, 0.1 part of vitamin B, 0.1 part of vitamin B6 and 0.1 part of gamma-aminobutyric acid. The traditional single target spot limitation is broken through, a synergistic effect system of tonifying the spleen and soothing the nerves-neurotransmitter regulation and control-intestinal brain axis regulation is formed, a buffer solution of pH simulation biological fluid is adopted as a non-organic extraction medium in the process, the ultrasonic cavitation effect and the plasma activation effect are combined, the temperature is controlled in the whole process, and the preparation method is simple and easy to implement. The problems of vortex, uneven extraction, dead volume, solvent residue, active ingredient damage and the like in traditional extraction are fundamentally solved, the composition capable of effectively improving the sleep quality is obtained, and animal model and crowd experiments prove that the composition can effectively improve the sleep quality and achieve a good sleep aiding effect.

The invention discloses a preparation method of a high-activity exosome hair growth promoter, which comprises the following steps: providing purified exosome, and mixing the purified exosome with hair growth active ingredients in a PBS (Phosphate Buffer Solution) with the pH value of 7.0-7.6, adding hydroxypropyl-beta-cyclodextrin with the final concentration of 0.5%-2% (w / v) and trehalose with the final concentration of 5%-10% (w / v), mildly incubating for 1-2 hours under the conditions that the temperature is 35-37 DEG C and the speed is 50-100 rpm, purifying, and freeze-drying to obtain a solid product. According to the invention, through the synergistic effect of the specific membrane permeability enhancer and the membrane stabilization protective agent, the efficient loading of the hair growth active component and the natural biological activity of the exosome are considered, the process is mild and controllable, the industrial amplification is easy, and the solid preparation solves the problem of inconvenient storage and transportation, and has strong practicability.

The invention provides a sodium ion specific fluorescence labeled transparent soil sample as well as a preparation method and application thereof, and belongs to the technical field of rock soil and geological engineering. The method comprises the following steps: firstly, sequentially carrying out hydrophilization treatment, solvent evaporation and dissolution on a sodion combined benzofuran isophthalate probe to obtain a probe mother solution; mixing the probe mother solution, a buffer solution, an inorganic sodium salt solution and a solvent to prepare a fluorescence labeling pore solution; and finally, mixing the sodium polyacrylate particles and the fluorescence labeled pore liquid, and performing vacuum saturation treatment to obtain the transparent soil sample. The transparent soil sample provided by the invention still keeps excellent optical transparency while having sodium ion specific response capability, so that a stable and reliable experimental medium is provided for in-situ, real-time and full-field observation of sodium ion migration.

The invention discloses a folic acid modified active oxygen response type sodium alginate nano-carrier and application thereof, and the preparation method comprises the following steps: firstly synthesizing-Se-Se-FA: stirring dicyclohexylcarbodiimide, 4-dimethylaminopyridine, dimethyl sulfoxide / pyridine, a double-selenium fragment and folic acid at room temperature for 18-22 hours in an argon environment; and carrying out acetone precipitation, centrifugation, washing, rotary evaporation concentration and freeze-drying. The preparation method comprises the following steps: preparing an ALG-Se-FA carrier, stirring sodium alginate, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and hydroxysuccinimide in a 2-morpholinoethanesulfonic acid buffer solution, adding DMSO, dissolving a double-selenium fragment and a-Se-Se-FA fragment in DMSO and deionized water, adding the dissolved double-selenium fragment and-Se-Se-FA fragment into a system, stirring, dialyzing, and freeze-drying to obtain the product. According to the carrier, a double-selenium bond ROS response unit and folic acid targeting molecules are introduced through covalent bonds, astaxanthin can be efficiently entrapped and protected, and after the carrier is stable in gastrointestinal environment and reaches a colitis disease part, high ROS level can be responded, and intelligent drug slow release is achieved through folic acid receptor targeting.

The invention relates to an MPL composite adjuvant and a preparation method thereof, and belongs to the technical field of vaccine adjuvants. The composite adjuvant comprises neutral phospholipid, anionic phospholipid, cholesterol, monophosphoryl lipid A, QS-21 and surface modified lipid. The preparation method comprises the following steps: dissolving a lipid component in an organic solvent to form a mixed solution, evaporating the solvent to form a lipid film, adding a buffer solution, hydrating to form a liposome suspension, performing ultrasonic treatment to obtain small single-layer liposome, and mixing the small single-layer liposome with a QS-21 micelle solution. By introducing the surface modified lipid, the stability of the adjuvant is remarkably improved, the adjuvant is small in particle size, uniform in distribution, high in Zeta potential negative value and good in stability in a serum environment, can induce high-level antibody immune response, and is suitable for vaccine development.

The invention discloses a lithium-rich manganese-based positive electrode material precursor as well as a preparation method and application thereof, and relates to the technical field of lithium ion battery positive electrode materials. Comprising a nucleation stage, a growth stage and an aging stage, in the nucleation stage, a precipitant solution, a metal salt solution, a complexing agent solution and a buffering agent solution are added into a reaction container in a parallel flow mode, and pH is controlled; in the growth stage, the pH is controlled, and feeding is stopped after D50 and the span meet the requirements. The parallel flow addition of the buffer agent solution is beneficial to adjusting the precipitation rate of a reaction system, and a lithium-rich manganese-based positive electrode material precursor with low particle size, high tap density, high specific surface area, high sphericity and dense morphology is obtained; the preparation method has obvious stability, reproducibility and superiority, and provides great convenience for batch production.

The invention provides a preparation method and application of an air-stable sulfide composite electrolyte, and the method comprises the following steps: S1, weighing an M source (M = Cd, Mn and Zn), P2S5 and S powder according to a ratio of 1: 1: 3, adding iodine for catalysis, carrying out heat preservation at 700-720 DEG C for 6-7 days, and carrying out K + insertion, Li + exchange and ultrasonic centrifugation to prepare a LiMyPS3 nanosheet dispersion liquid; s2, dissolving PEO and LiTFSI in acetonitrile to form a film, drying to obtain a pure PEO film, immersing the pure PEO film into a dopamine Tris buffer solution with the concentration of 2 mg / ml and the pH value of 8.5, oscillating for 12-24 hours in an oxygen environment, and washing and drying to obtain a PDA-coated PEO film; and S3, carrying out suction filtration on the LiMyPS3 dispersion liquid to obtain a self-supporting membrane, stacking according to the sequence of "PDA-coated PEO membrane-sulfide membrane-PDA-coated PEO membrane", carrying out isostatic pressing at 10-20 MPa, and then carrying out vertical cutting at 0 DEG C to obtain the 20-30 [mu] m composite membrane. The film has the advantages of good air stability, almost no loss of conductivity after 30 days, room temperature conductivity of 9.2-10.2 ms / cm, excellent interface bonding force and mechanical strength, and stable window of 4.3-4.5 V, is adaptive to a high-voltage positive electrode, and can be used for a high-energy-density solid-state lithium battery.

The present application relates to a controllable preparation method of a colloidal crystal capillary column and its application in biomolecule separation, and specifically comprises the following steps: a plunger and an electroosmotic pump are prepared in situ at one end of a capillary; a buffer solution containing monodisperse colloidal particles is filled in an upper reservoir of an electric field assembly device, and a buffer solution is filled in a lower reservoir; the capillary is filled with the buffer solution, and the end of the capillary containing the electroosmotic pump is inserted into the lower reservoir; the dispersion of the colloidal solution is maintained by applying oscillation to the upper reservoir, an electric field is applied between the two reservoirs to make the colloidal particles move to the electroosmotic pump under the action of an electroosmotic flow, and a three-dimensional colloidal crystal is assembled; and the capillary is supplemented with an ultrasonic force to reduce lattice defects. The present application has the advantages of simple preparation process, controlled directional movement of colloidal particles through an electric field, improved assembly efficiency and quality of the three-dimensional colloidal crystal, and controllable assembly of the colloidal particles under the action of an electric field through regulation and control of the length and surface charge of the electroosmotic pump.

The invention provides a method for synchronously and rapidly detecting Escherichia coli and multiple drug-resistant genes thereof, which comprises the following steps: culturing a sample at night to obtain a bacterial solution to be detected, adding a buffer solution and a metal bath, centrifuging, taking a supernatant, detecting by micro-fluidic, optimizing the extraction process of nucleic acid in the sample, designing an optimal RPA primer probe group, and detecting the multiple drug-resistant genes of the Escherichia coli. A reasonable RPA coupled microfluidic detection system is established, synchronous and rapid detection of the escherichia coli uidA and I-type integrase gene intI1 thereof and drug-resistant genes sul1 and aadA5 is realized, the specificity is high, the sensitivity is high, the reaction time is short, the operation is convenient, and a method support is provided for monitoring and prevention and control of food-borne drug-resistant bacteria.

This invention provides a simple synthesis method for Fe-Ag / CMP nanopolymers with catalase-like activity and their application in hydrogen peroxide detection, belonging to the field of bioanalytical technology. The method of this invention includes the following steps: (1) preparing a 4-hydroxyethylpiperazine thiosulfonic acid (HEPES) standard buffer solution; (2) adding cytidine monophosphate (CMP) to the solution obtained in step (1) and stirring until the CMP is fully dissolved. Then, under vigorous stirring, ferric nitrate aqueous solution and silver nitrate aqueous solution are added sequentially, at which point the colorless solution turns pale yellow; (3) transferring the mixed solution obtained in step (2) to a centrifuge tube, centrifuging at 12000 rpm for 8 min to collect the precipitate, washing it three times with distilled water, and finally adding 4 mL of distilled water to obtain a 1 mg / mL Fe-Ag / CMP suspension. This invention utilizes CMP as a biological ligand and Ag... + Fe 3+ Simultaneous coordination, and the reducing amino groups on CMP can directly transfer Ag... + In situ reduction to silver nanoparticles (AgNPs) led to the one-step synthesis of a bimetallic Fe-Ag / CMP nanopolymer with hydrogen peroxide-like nanozyme activity, enabling the detection of hydrogen peroxide.

The utility model discloses a blood detection device. The blood detection device comprises a shell, test paper and a cap, the shell comprises an upper shell and a lower shell which are fixedly connected, a containing cavity is formed between the upper shell and the lower shell, the test paper is located in the containing cavity, a blood sampling head is formed at the front end of the shell, a liquid inlet is formed in the blood sampling head, and the liquid inlet is communicated with the containing cavity through a capillary structure and a premixing cavity in sequence; a hydrophobic coating belt arranged in the left-right direction is arranged on the front cavity wall of the premixing cavity, and an air hole communicated with the containing cavity is formed in the rear end of the shell; the front end of the shell is sleeved with the cap, a liquid storage bag is arranged at the bottom in the cap, and buffer liquid is stored in the liquid storage bag. The blood detection device can realize integration of sample collection and sample treatment, and has the advantages of simple structure, low manufacturing cost, convenience in use, high detection success rate, high detection accuracy and the like.

The present invention proposes a method and use for stabilizing a simple agglomerate for pH and salt and with adjustable size. In phosphoric acid buffer solutions with different salt concentrations and pH values, the polyacrylic acid hydroxypropyl group condensation body has specific stability; hydrophobic thermal response blocks are introduced into a hydroxypropyl acrylate monomer through reversible addition-fragmentation chain transfer polymerization to regulate and control the size of a condensation body, and a phase separation behavior is shown at different temperatures; a hydrophobic block without thermal response is introduced to regulate and control the size of the aggregate, and no thermal response behavior is shown. Continuous regulation and control of the size of the aggregate from the micron level to the nano level are achieved, and the requirements of different application scenes are met. The hydroxypropyl polyacrylate condensation body can be used for packaging various dyes and drugs; high-efficiency enzyme protection is achieved, formed aggregates can protect glucose oxidase, and the retention rate of enzyme activity reaches 85% or above after treatment is conducted for 3 hours at 60 DEG C; as a micro-reactor for the reaction of generating p-nitrobenzaldehyde phenylhydrazone from p-nitrobenzaldehyde and phenylhydrazine, the reaction rate is greatly improved.

The embodiment of the invention provides a preparation method of octahedral Ag2O nano-enzyme and a method for detecting H2O2 through a colorimetric method, and relates to the technical field of H2O2 detection. The method for detecting H2O2 by using the colorimetric method comprises the following steps: step S11, taking a plurality of centrifugal tubes, adding quantitative Ag2O solution and H2O2 with different concentrations into each centrifugal tube, and uniformly mixing; step S12, adding a NaAc-Hac buffer solution and a TMB (Tetramethylbenzidine) solution into each centrifugal tube treated in the step S11 to form an Ag2O-TMB-H2O2 reaction system, heating the Ag2O-TMB-H2O2 reaction system in each centrifugal tube in a water bath for a preset time, and observing the color change of the solution in each centrifugal tube; and step S13, determining a light absorption value of the Ag2O-TMB-H2O2 reaction system at a preset wavelength through an ultraviolet photometer, and recording data. The method for detecting H2O2 through the colorimetric method has the advantages of being simple in operation process, accurate in detection, visual in result and the like.

The application discloses a method for synthesizing high-concentration furfuryl alcohol by using a double-enzyme coupling method, and the method comprises the following steps: mixing alcohol dehydrogenase freeze-dried bacterial powder and glucose dehydrogenase freeze-dried bacterial powder to serve as a catalyst, using furfural as a substrate, using glucose as a co-substrate, using NADP + or NAD + as a coenzyme, using a buffer solution with a pH value of 4-9 as a reaction medium to form a reaction system, and reacting completely under the condition of 20-50 DEG C and 400 rpm, then separating and purifying the reaction liquid to obtain furfuryl alcohol. The biological catalytic system is suitable for furfural with a concentration higher than 500 mM, and 100% conversion of 500 mM can be realized within 10 hours. The substrate continuous flow process is further used to eliminate the inhibition of aldehyde substrates on the biological catalyst, the concentration of the product can reach 1500 mM, and the highest space-time yield can reach 235 g / (L.d).

The application discloses a kind of composite super-hydrophobic paper based on alkyl ketene dimer and metal polyphenol network and preparation method thereof, belong to functional paper-based material field.The method is first immersed in 0.25%~5% alkyl ketene dimer emulsion in cellulose paper, is dried at 90~110 DEG C and is cured 48-96h to prepare modified paper;Then, the pH is 8.0-9.0 of tris-hydroxymethyl aminomethane hydrochloride buffer solution, hydrochloric acid dopamine is dissolved in the buffer solution to form dopamine solution, and the concentration is 0.25~20mg / mL of metal ion solution;Finally, the modified paper is immersed in dopamine solution and metal ion solution in turn, and is dried to obtain composite super-hydrophobic paper.The obtained composite super-hydrophobic paper uses cellulose paper-based material as substrate, and hydrophobic layer and metal polyphenol network layer are formed on the surface in turn, the composite paper has super-hydrophobic performance, water barrier performance and photo-thermal response performance, the preparation process is simple, and is suitable for waterproof packaging, self-cleaning surface, anti-icing and deicing and photo-thermal antibacterial and other fields.

The application discloses a kind of copper azide content trace detection method, the detection method includes: detecting copper azide content: taking the sample to be measured and inorganic acid mixed dissolution, then sequentially adding NaOH solution, buffer solution and copper nitrate solution, using ultraviolet visible spectrophotometer to measure absorbance and calculate corresponding azide radical concentration, determine the content of copper azide and cuprous azide in the sample to be measured by azide radical and copper azide content relationship model;Detect copper azide and cuprous azide: on the basis of measuring copper azide content, determine the content of copper azide and cuprous azide in the sample to be measured by azide radical and copper azide / cuprous azide content relationship model.The copper azide content trace detection method needs simple device of the application, low requirement to equipment, does not need organic solvent or color developing agent, and environmental pollution is small, and sub-milligram level copper azide used in MEMS fuze can be detected.

The invention relates to a low-temperature gradient enzymolysis technology for collagen peptide in the body wall of a sea cucumber, and discloses mild decomposition and efficient extraction of collagen in the body wall of the sea cucumber by virtue of a multi-section temperature zone reaction, enzyme seed compounding control and on-line regulation system. And the collagen peptide with concentrated molecular weight, strong biological activity and high terminal product quality is prepared by the low-temperature gradient enzymolysis technology. The method is characterized by comprising the following steps: cutting the body wall of the sea cucumber to obtain a particle size suitable for enzymolysis, adding the cut body wall of the sea cucumber into a neutral buffer solution, stirring at normal temperature, and adjusting the pH value to 6.5-7.5, so that the tissue of the body wall of the sea cucumber is fully expanded and uniformly dispersed to be more suitable for the subsequent enzymolysis process; the method comprises the following steps: carrying out staged reaction on the body wall of the sea cucumber and an enzyme at different temperatures, carrying out fine separation and terminal treatment on an enzymatic hydrolysate, and immediately cooling a system to 4 DEG C after the reaction of the enzymatic hydrolysate is finished.

This invention discloses a high-precision patterned hydrogel, its preparation method, and a flexible electronic device. The preparation method of the high-precision patterned hydrogel includes the following steps: using a buffer solution containing polyethylene glycol thiol derivatives and hydrogen peroxide as a prepolymer solution (prepolymer solution 1), applying the prepolymer solution 1 to the surface of a substrate, and reacting to obtain a substrate with a thin film; using an aqueous solution containing a monoene water-soluble monomer, a diene water-soluble monomer, a water-soluble photoinitiator, and a polymerization inhibitor as a prepolymer solution (prepolymer solution 2), immersing the substrate with the first thin film in the prepolymer solution 2; after immersion, washing and solvent removal to obtain a substrate with a dry film; photolithographically patterning the substrate with the dry film, and then removing unexposed areas with a developer to obtain the high-precision patterned hydrogel. This invention can effectively improve the precision of the patterned hydrogel, while also giving the high-precision patterned hydrogel high biocompatibility and ion permeability.

The application belongs to the technical field of battery recycling, and discloses a flotation depressant, a preparation method and application thereof. The flotation depressant comprises catechol, an oxidizing agent and a weak acid buffer solution, and the pH value of the flotation depressant is 4-6.5. The catechol and the oxidizing agent are dissolved in the weak acid buffer solution to prepare the flotation depressant, the flotation depressant can selectively inhibit the flotation of the positive electrode material, and thus the positive electrode material and the negative electrode material are separated through reverse flotation. The flotation depressant is used for flotation to obtain the positive electrode material rich in cobalt, and the grade and the recovery rate of the positive electrode material are as high as 90% and 83% respectively. The preparation method of the flotation depressant is simple, the cost is low, the flotation depressant is friendly to the environment, and the flotation depressant has a good application prospect in industrial battery recycling.

The invention relates to the technical field of biological catalysis engineering, in particular to a method for improving the solubility of stevioside Reb M and Reb D through enzyme catalysis modification, which comprises the following steps: dissolving Reb M and Reb D with the purity of more than or equal to 90% in a buffer solution with the pH value of 4.0-8.0, adding a non-starch glycosyl donor and composite glycosyl transferase according to the enzyme-substrate mass ratio of 0.05-0.5, and optimizing the enzyme addition sequence to realize specific site modification; reacting for 6-24 hours under the conditions that the pH is 5.5-6.0 and the temperature is 60-85 DEG C, and controlling the proportion of DP2-3 to be 60-80%; hPLC sampling is carried out every 4-6 hours, and the unreacted substrate is less than or equal to 20%; the solubility of the product is greater than or equal to 25g / L, and the sweet taste of the product is pure. According to the method, the solubility of Reb M / Reb D is improved, the structure of a directional glycosylation controlled product is realized, and pure sweetness is reserved; the reaction is mild and controllable, enzyme inactivation is simple and free of residues, industrialization is easy, and stevioside application upgrading is promoted.