3378 results about "Poly ethylene" patented technology

The invention discloses a machine learning assisted polyethylene reaction performance prediction model training method, prediction method and device. The method comprises the following steps: acquiring a training set; screening feature items used for model training; obtaining a gradient boosting regression model for catalytic activity, a gradient boosting regression model for molecular weight and a gradient boosting regression model for molecular weight distribution; extracting feature items for model training from the data of the training set so as to obtain feature vectors; and respectively inputting the feature vectors into each model so as to train each model, thereby respectively obtaining hyper-parameters of the trained gradient-boosted regression model for catalytic activity, hyper-parameters of the trained gradient-boosted regression model for molecular weight and hyper-parameters of the trained gradient-boosted regression model for molecular weight distribution. According to the method, a model relationship between input characteristics and polymerization results (including catalytic activity, molecular weight, molecular weight distribution and the like) is established through training set learning.

In some embodiments, a cable can include an electrically conductive inner core. A first insulation layer can be disposed about the inner core. An electrically conductive layer can be disposed about the first insulation layer. A second insulation layer can be disposed about the electrically conductive layer. A first polymer jacket can be disposed about the second insulation layer. The first polymer jacket can include a first layer of armor strength members disposed therein. A second polymer jacket can be disposed about the first polymer jacket. The second polymer jacket can include a second layer of armor strength members disposed therein. An outer polymer jacket can be disposed about the second polymer jacket. At least one of the first polymer jacket, the second polymer jacket, and the outer polymer jacket can be formed from an aliphatic polyketone polymer, an ethylene-propylene copolymer, a polyolefin elastomer, a polypropylene, or a cross-linkable polyethylene.

The invention discloses an antibacterial drug delivery system based on a dynamic response type microneedle patch and a preparation method, and belongs to the field of biomedical materials.The antibacterial drug delivery system comprises a substrate layer and a needle point layer arranged on the surface of the substrate layer, the substrate layer is a mixed matrix of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), and the needle point layer is made of nano-silver; the needle tip layer is a phenylboronic acid modified oxidized hyaluronic acid and polyvinyl alcohol composite system. The antibacterial drug delivery system based on the dynamic response type microneedle patch, namely the microneedle patch with the pH response drug release function, is suitable for antibacterial treatment of infectious wounds, the mechanical strength of the needle point layer is improved, it can be better guaranteed that a microneedle completely penetrates into the skin, and the delivery efficiency is improved; meanwhile, drug release can be responded according to the pH of a bacterial infection part, and the antibacterial effect is good.

The invention relates to the technical field of conductive materials, in particular to a high-concentration dispersion system and a preparation method thereof. The high-concentration dispersion system comprises a conductive agent, a dispersing agent, a solvent and a viscosity reduction auxiliary agent, the conductive agent is modified carbon nanotubes, the dispersing agent is modified polyvinylpyrrolidone, the solvent is N-methyl pyrrolidone or deionized water, and the viscosity reduction auxiliary agent is piperazine anhydrous; wherein the modified carbon nano tube is obtained by mixing and heating a carbon nano tube and a mixed acid solution of nitric acid and sulfuric acid, then cooling, filtering, washing, drying, then dispersing in 75% ethanol, and finally adding 3-[3-carboxyl allylamido] propyltriethoxysilane for modification; the modified polyvinylpyrrolidone is obtained by heating polyvinylpyrrolidone at 310-330 DEG C and then oxidizing the polyvinylpyrrolidone. The conductive agent content of the high-concentration dispersion system is high, the conductive agent accounts for 15%-20% of the high-concentration dispersion system by mass, and the high-concentration dispersion system is low in viscosity, high in dispersity and good in conductivity.

The invention provides a diaphragm and a preparation method thereof and a lithium ion battery, the diaphragm comprises a base membrane layer and a composite functional layer, the composite functional layer comprises hydrophobic SiO2 aerogel modified by a hydrophobic agent, a conductive ion polymer and a solid electrolyte, and the composite functional layer respectively accounts for 3-12wt%, 0.5-1.0 wt% and 0.5-1.5 wt% of the total mass of the diaphragm; the hydrophobic agent comprises trimethylchlorosilane, hexamethyldisilazane, perfluorooctyltriethoxysilane, polyvinylidene fluoride, polydimethylsiloxane and the like, the conductive ionic polymer comprises polyvinylpyrrolidone, lithium polymethacrylate, lithium polystyrene sulfonate, polyacrylamide and the like, and the solid electrolyte comprises lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide and the like. The wettability is improved by the high porosity of the hydrophobic SiO2 aerogel, the stability and strong conductivity of a physical conductive network of the solid electrolyte and the ion affinity and amphoteric binding capacity of the conductive ion polymer are optimized, the electrochemical performance and thermal stability of the interface are optimized, and comprehensive optimization of the thermal-electric-interface performance of the diaphragm is realized through combination.

The application provides a high-voltage cable preparation method and a high-voltage cable. The preparation method comprises the following steps: preparing modified polyvinyl chloride, wherein the modified polyvinyl chloride comprises polyvinyl chloride and a filler added into the polyvinyl chloride; taking 100 parts by weight of the polyvinyl chloride as a base material, and the filler comprises the following components in parts by weight: 1-2 parts of polyethylene, 2-3 parts of a filler, 2-3 parts of a lubricant and 2-5 parts of a toughening agent; extruding the modified polyvinyl chloride on the outer surface of a smooth metal sheath layer to form a modified polyvinyl chloride sheath, and the modified polyvinyl chloride sheath is bonded to the smooth metal sheath layer; and the smooth metal sheath layer is wrapped on the outer surface of a cable core. The high-voltage cable preparation method can greatly improve the flame-retardant performance of the high-voltage cable.

The invention discloses a cerium-modified manganese-based NH3-SCR (Selective Catalytic Reduction) denitration catalyst as well as a preparation method and application thereof. The catalyst is obtained by uniformly mixing and stirring manganous nitrate, cerous nitrate, polyvinylpyrrolidone, citric acid and deionized water, stirring and evaporating to a gel state, drying to form a precursor, and roasting the precursor in an air atmosphere. Ce is used for modifying MnOx, polyvinylpyrrolidone and citric acid are used as a surfactant and a complexing agent in the preparation process of the catalyst, the interaction between Ce and Mn is enhanced, the phase of the catalyst is adjusted, and under the conditions of high NOx concentration (1000 ppm) and high space velocity (GHSV = 120,000 mL h <-1 > g <-1 >), the catalyst can be used for preparing the catalyst, and the catalyst can be used for preparing the catalyst. The catalyst has excellent low-temperature catalytic activity, a wide working temperature window and good reaction stability, and has good water resistance and sulfur dioxide poisoning resistance.

The invention provides a preparation method and application of a quantum dot light-emitting diode based on interface modification, and belongs to the technical field of quantum dot materials. The preparation method comprises the following steps: (1) spin-coating PEDOT: PSS-4083 on ITO (Indium Tin Oxide) to obtain a hole injection layer; (2) spin-coating polyvinyl carbazole on the hole injection layer in the step (1) to obtain a hole transport layer; (3) spin-coating pyridine on the hole transport layer in the step (2) to obtain a modification layer; (4) spin-coating ZnCdS / ZnS quantum dot normal octane on the modification layer in the step (3) to obtain a quantum dot film; and (5) spin-coating an Mg-doped ZnO ethanol solution on the quantum dot film in the step (4), and performing high-vacuum evaporation to obtain the quantum dot light-emitting diode. Compared with an original device, the EQE of the prepared quantum dot light emitting diode is improved by 16.5%, and the highest brightness is improved by 12.5%.

A dry eye composition containing hypochlorous acid and a demulcent. The demulcent can be polyvinylpyrrolidoe with a molecular weight of 30-50 kDa. The composition can be applied to the surface of the eye with a dropper device or a spray dispenser. Critically, hypochlorous acid is stable in the dry eye composition and maintains its effectiveness at preventing microbial growth.

The invention discloses a preparation method of a 3-micron ultrathin lithium battery copper foil. The preparation method comprises the following steps: preparing a copper sulfate electrolyte; a wetting agent, a brightening agent and a high resistance agent are added into the copper sulfate electrolyte, the high resistance agent is at least one of thiazolidinethione, polyethyleneimine, 2-mercaptobenzimidazole and ethylene thiourea, and a mixed additive is formed; polishing and grinding a cathode roller by adopting a flying wing wheel, and carrying out electrolytic treatment on the mixed additive through the polished and ground cathode roller to obtain a first-stage copper foil; and the first-stage copper foil is placed in a nitrogen furnace to be subjected to annealing treatment, and the 3-micron ultrathin lithium battery copper foil is obtained. The invention aims to solve the technical problems that in the prior art, edge tearing, foil breaking, warping, dark appearance oxidation and the like are prone to occurring in the production process of the ultrathin copper foil, the tensile strength and the ductility are difficult to consider at the same time, and stable mass production of the 3-micron copper foil is still difficult.

The invention relates to the technical field of cable preparation, and provides a high-temperature-resistant flame-retardant cable, which comprises a cable core, and an insulating layer and a sheath layer which sequentially coat the cable core from inside to outside, the sheath layer is prepared from the following components in parts by weight: 8 to 10 parts of ethylene-vinyl acetate copolymer, 15 to 18 parts of ethylene-acrylate copolymer, 15 to 18 parts of polyvinyl chloride resin, 15 to 20 parts of filler, 10 to 12 parts of modified glass fiber, 3 to 4 parts of maleic anhydride grafted polyethylene, 0.5 to 1 part of ultraviolet absorbent, 1 to 2 parts of antioxidant and 1 to 2 parts of coupling agent. The cable has the beneficial effects that through introduction of the modified glass fiber and the functional monomer, the mechanical property and the flame retardant grade of the cable are improved, and the stability of the cable in a high-temperature environment is also remarkably enhanced.

The invention relates to a particulate composition comprising, or substantially consisting of, urea, an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor, and an additive, wherein the additive comprises components (i), (ii), and optionally (iii): (i) one or more polyhydric alcohols; preferably one or more carbohydrates, preferably selected from monosaccharides, disaccharides, and oligosaccharides; (ii) a first polymer, preferably an amine-containing polymer; more preferably a polyvinylamine or a polyalkyleneimine; and (ii) optionally, a second polymer, preferably a polar polymer; more preferably a water-soluble polar polymer. The invention further relates to a process for producing the particulate composition, an additive for a particulate composition, and the use of the particulate composition as a fertilizer.

The invention discloses a cable insulating material which comprises the following components in parts by weight: 40-60 parts of low-density polyethylene, 20-30 parts of an ethylene-vinyl acetate copolymer EVA, 2-5 parts of a composite anti-aging agent, 5-10 parts of a core-shell structure nano composite modifier, 1-2 parts of a lubricant, 3-8 parts of a compatilizer, 20-30 parts of a composite flame retardant, 5-10 parts of a nano reinforcing agent and 2-4 parts of phenylsilane. The core-shell structure modifier strengthens interface bonding, and cooperates with the modified nano reinforcing agent to disperse stress, so that the mechanics and high and low temperature resistance are improved; the composite anti-aging agent inhibits multi-path aging and improves the aging resistance. The material has the advantages of excellent mechanical properties, high and low temperature resistance and outstanding aging resistance, and meets the insulation quality and efficiency requirements of cables in complex use environments.

The invention discloses a low-temperature vacuum microwave freeze-dried sinomenine hydrochloride preparation and a preparation method thereof in the technical field of pharmaceutical preparations, and solves the problems of long drying time, high energy consumption and poor product stability in the traditional freeze-drying technology. A vacuum microwave collaborative freeze-drying technology is adopted, microwave internal heating is achieved through a 2.45 GHz magnetron microwave generator and a rectangular waveguide tube under the conditions that the vacuum degree is 20-30 Pa and the plate layer temperature ranges from-40 DEG C to-35 DEG C, the microwave power density in the primary drying stage ranges from 0.3 W / g to 0.5 W / g, the microwave power density in the secondary drying stage ranges from 0.1 W / g to 0.3 W / g, and collaborative control over the microwave power, the vacuum degree, the temperature and the time is achieved in cooperation with a quaternary coupling precise control system. The preparation contains 50 mg of sinomenine hydrochloride, 100 mg of mannitol and 10 mg of sodium carboxymethyl cellulose grafted modified polyvinylpyrrolidone, the residual moisture is controlled to be 0.4-0.6%, the activity retention rate is 94-96%, and the drying time is shortened to 12-16 hours.

The invention discloses a high-strength water-resistant starch adhesive and a preparation method thereof, and belongs to the technical field of preparation of environment-friendly adhesives. The problems of strength and mildew resistance of the starch adhesive are solved. The preparation method comprises the following steps: preparing 5-10g of polyethyleneimine into a 30-60wt% solution, weighing a certain mass of urea according to a molar ratio of (1-5): 1, adding the weighed urea into the prepared polyethyleneimine solution, and reacting for 8-14 hours in an oil bath to obtain a first branched polymer; 20-50 g of dialdehyde starch and 60-90 g of polyvinyl alcohol are added into a flask to prepare a starch solution, then the reaction temperature is set, uniform stirring is performed for gelatinization treatment, a second gelatinized solution is obtained, and after mixing reaction, a prefabricated high-strength water-resistant starch adhesive is obtained; and adding 5-10 g of cassava starch filler and 5-10 g of polymethyl silicon polyphenyl isocyanate, and stirring for 10-30 minutes to obtain the high-strength water-resistant starch adhesive.

The invention belongs to the technical field of gene engineering, and discloses a CRISPR / Cas9 delivery system and application thereof. The CRISPR / Cas9 delivery system is obtained by loading the CRISPR / Cas9 system with the fluorinated polyethyleneimine, and the fluorinated polyethyleneimine can deliver the CRISPR / Cas9 carrier into cells, has excellent transmembrane delivery efficiency, and can efficiently mediate the CRISPR / Cas9 system to enter target cells. The CRISPR / Cas9 delivery system is applied to large-scale breeding of aquatic animals, the use safety is high, the biocompatibility is excellent, and the delivery system has excellent gene editing efficiency and has wide application prospects in the field of gene editing breeding.

The invention relates to the technical field of cables, and provides a high-temperature-resistant flame-retardant cable and a preparation method thereof. The high-temperature-resistant flame-retardant cable comprises a conductor and a flame-retardant outer sheath, the flame-retardant outer sheath is prepared from the following raw materials in parts by weight: 40 to 50 parts of linear low-density polyethylene, 35 to 45 parts of ethylene-vinyl acetate copolymer, 10 to 15 parts of ethylene propylene diene monomer, 15 to 18 parts of modified aluminum hydroxide, 10 to 14 parts of modified magnesium hydroxide, 5 to 8 parts of polyethylene grafted maleic anhydride, 5 to 8 parts of microencapsulated red phosphorus, 2 to 3 parts of silane coupling agent and 0.8 to 1 part of antioxidant. The composite material is prepared from the following components in parts by weight: 0.5-1 part of a light stabilizer, 0.5-1 part of calcium stearate, 0.8-1 part of polyethylene wax and 0.5-0.9 part of carbon nanotubes. According to the cable prepared in the invention, the performance stability of an existing high-temperature-resistant material in a high-temperature environment is improved, and the problems of softening, melting and the like of the cable are avoided.

The invention relates to a cellulose-chitosan-based lithium ion battery diaphragm and a preparation method and application thereof.The preparation method of the diaphragm comprises the steps that gamma-polyglutamic acid and polyamide epichlorohydrin are adopted for modifying chitosan, the hydrophilicity and the liquid absorption capacity of the chitosan are improved, polyvinylpyrrolidone is adopted for coating the chitosan, and the hydrophilicity and the liquid absorption capacity of the chitosan are improved; pVP is replaced in ethanol soaking to form micropores, so that the porosity of the modified chitosan is improved. Amino groups and hydroxyl groups of the modified chitosan are combined with catechol of the polydopamine and hydroxyl groups of the hydroxy propyl cellulose through hydrogen bonds and covalent bonds to form a chitosan-cellulose-PDA interpenetrating network, and the diaphragm material suitable for the lithium ion battery is finally prepared by combining hot-pressing shaping. The preparation method has the advantages that the balance between the mechanical property and the ion conduction property of the diaphragm is realized through multi-component compounding by utilizing the biocompatibility and renewability of natural macromolecules (cellulose and chitosan).

The invention discloses a method for preparing a micro-particle-size negative oxygen ion purifying agent from a nano material, and relates to the technical field of air purifying agents, the method comprises the following preparation steps: step 1, pouring 5-6.5 g of modified tourmaline powder and 10 g of an amino acid-nano particle compound into 200 mL of deionized water, then adding 0.5-0.54 g of polyvinylpyrrolidone, carrying out ultrasonic treatment for 30-40 min, then adding 0.5-0.54 g of polyvinylpyrrolidone into the deionized water, carrying out ultrasonic treatment for 30-40 min, and carrying out ultrasonic treatment for 30-40 min; carrying out ball milling until the particle size is 1-5 microns; 2, adding 2-2.6 g of a chitosan solution with the concentration of 1% after ball milling, adjusting the pH value of the system to 6, and stirring at 50 DEG C for 1 h; according to the method for preparing the micro-particle-size negative oxygen ion purifying agent from the nano material, tourmaline powder is modified, so that the surface hydroxylation degree of the tourmaline powder is improved, lattice defects are increased, the negative oxygen ion release efficiency is remarkably improved, meanwhile, the tourmaline powder is compounded with white carbon black, interface charge conduction can be enhanced, and continuous release of negative oxygen ions is further promoted.

The invention belongs to the technical field of membrane separation, and particularly relates to a method for preparing a high-flux hollow fiber nanofiltration membrane based on interfacial polymerization, the obtained membrane and application. The method comprises the following steps: firstly, carrying out pre-adsorption treatment on a polyethersulfone hollow fiber ultrafiltration base membrane through a polyethyleneimine aqueous solution to form a reactive anchoring layer; then sequentially dipping in an aqueous phase solution containing piperazine, sodium phytate and nanoscale cellulose whiskers and an organic phase solution containing trimesoyl chloride and 5-isocyanate isopeptide acyl chloride for interfacial polymerization; and finally, carrying out heat treatment on the obtained primary composite membrane, and completing a gas-phase cross-linking reaction in a glutaraldehyde steam atmosphere. According to the method, the hollow fiber nanofiltration membrane with high flux, high selectivity, excellent chlorine resistance and pollution resistance is successfully prepared through a multi-stage strengthening process, and the hollow fiber nanofiltration membrane is suitable for the fields of drinking water purification, industrial wastewater reuse, material separation and the like.

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 producing multimodal polyethylene through series connection of multiple reactors, and belongs to the field of olefin polymerization. The low-molecular-weight or medium-molecular-weight ethylene polymer is produced through polymerization in the first reactor, the obtained product enters the intermediate treatment unit to remove hydrogen, and then part of the product is shunted to enter the second reactor to be mixed with the ultra-high-molecular-weight ethylene polymer produced through ethylene polymerization in the second reactor; all polymers of the second reactor are returned to the intermediate treatment unit, and the rest products after hydrogen removal enter a third reactor and are mixed with high-molecular-weight ethylene polymers generated by copolymerization of ethylene and comonomers in the third reactor to generate multimodal polyethylene. The multimodal polyethylene produced by the method is wide in molecular weight distribution, and the molecular weight of ultra-high molecular weight polyethylene is flexible to regulate and control. According to the invention, material circulation between the third reactor and the second reactor is adopted, molecular chain-level mixing among the components is achieved, the compatibility is good, and the mechanical property is more excellent.

The invention relates to the technical field of biological separation materials, and discloses an amine-functionalized magnetic nano composite material and application thereof in protein separation and purification. The material has a core-shell structure and comprises a magnetic ferroferric oxide nano core, an ordered mesoporous silicon dioxide intermediate layer and a covalent grafted polyethyleneimine functional layer. By controlling the matching relationship between the pore diameter of mesopores and the molecular size of the polymer and adopting a crosslinking strategy, the material has high magnetic responsiveness, rapid mass transfer performance and high-density surface amino groups. The material shows high adsorption capacity, rapid adsorption kinetics and good cycle stability in the protein separation process, and is suitable for enrichment purification and metal chelating affinity separation of protein in a biological sample. According to the invention, the technical problems of low protein adsorption capacity, slow dynamics and poor cycling stability caused by compact shell layer, non-uniform amino distribution and limited mass transfer of the existing amine functionalized magnetic material are solved.

The invention belongs to the technical field of membrane separation, and particularly relates to a low-pressure high-flux polyamide / polysulfone hollow fiber composite nanofiltration membrane and a preparation method thereof. The preparation method of the composite nanofiltration membrane comprises the following steps: dissolving sulfonated polysulfone, poly (1-vinyl-3-butylimidazole) bromide and polyvinylpyrrolidone to prepare a spinning solution, and spinning to obtain a base membrane; carrying out hydrophilic modification on the base membrane by using 1, 3-propane sultone; then, an aqueous phase solution containing poly (gamma-glutamic acid) and triethylene tetramine and an organic phase solution containing trimesoyl chloride and 3, 5-diaminobenzoic acid are subjected to interfacial polymerization in the inner cavity of the modified base membrane to form a polyamide separation layer; and finally, carrying out heat treatment to obtain the composite nanofiltration membrane. Through the synergistic effect of zwitterionic ionization of the base membrane and biomacromolecule construction of the separation layer, the mass transfer resistance of water is remarkably reduced, unification of high flux and high selectivity is achieved, and good structural stability is achieved.

The invention discloses a preparation method of a CoMnFe-PBA hollow superstructure material, which combines seed induced self-assembly with an in-situ ligand / metal ion exchange growth method, and comprises the following steps: dissolving MOF-74 and potassium ferricyanide in deionized water, and carrying out ultrasonic treatment to form a solution A; dissolving polyvinylpyrrolidone, ferric chloride and manganese chloride tetrahydrate in a mixed solvent of ethanol and deionized water, and stirring for a certain time to obtain a solution B; dropwise adding the solution B into the solution A, stirring, carrying out centrifugal collection, ethanol washing and freeze drying on a reaction product, and collecting a sample to obtain the CoMnFe-PBA hollow superstructure material. According to the CoMnFe-PBA hollow superstructure material prepared through the method, a construction unit of a self-assembly superstructure is expanded to PBA nanoparticles, and the synthesis strategy, the construction unit, the structural level and the application range of the self-assembly superstructure can be further expanded.

The invention belongs to the field of nano-medicine and traditional Chinese medicine, and particularly discloses an antioxidant nano-material based on self-assembly of traditional Chinese medicine and copper ions and a preparation method thereof.The nano-material is prepared from BPCu nano-particles formed by self-assembly of berberine and procyanidine B2 under induction of the copper ions, the BPCu nano-particles are further subjected to surface modification through polyvinylpyrrolidone, and the antioxidant nano-material is prepared. And the stably dispersed PVP-coated BPCu nano structure is obtained. The material is small in particle size, uniform in distribution, good in water solubility and storage stability, excellent in free radical scavenging capacity and catalase-like activity and suitable for adjuvant therapy of oxidative stress related diseases, and the preparation method is easy and convenient to operate, does not need an organic solvent and has good industrialization and disease treatment potential.

The invention discloses application of sulfur quantum dot nanoparticles to improvement of plant waterlogging resistance. The invention provides sulfur quantum dot nanoparticles PEI-SQDs prepared from sulfur, sodium hydroxide, polyethylene glycol and polyethyleneimine. The sulfur quantum dot nanoparticles PEI-SQDs are simple in synthesis method, small in particle size, low in toxicity, low in price, simple to prepare, suitable for large-scale production, good in water solubility and good in biocompatibility; the compound has the capacity of removing active oxygen and ethylene in vitro, and can remove excessive active oxygen and ethylene in plants with waterlogging stress, relieve short-term waterlogging stress suffered by crops and recover growth and development of the crops when being applied to the plants with waterlogging stress; further, long-term waterflooding stress on the crops can be relieved, and the yield of the crops is increased; and the sulfur quantum dot nanoparticles are simple and convenient in use method and obvious in action effect.

The invention provides 3D tumor cell culture hydrogel as well as a preparation method and application thereof. The 3D tumor cell culture hydrogel is prepared from the following raw materials: polyvinylpyrrolidone and polyvinyl alcohol. The preparation method comprises the following steps: mixing a polyvinylpyrrolidone solution with a polyvinyl alcohol solution, adjusting the pH value, and freezing-unfreezing to obtain the 3D tumor cell culture hydrogel. The 3D tumor cell culture hydrogel provided by the invention does not need to be additionally added with a chemical cross-linking agent, and the material is high in biocompatibility and flexible in modulus adjustment, and can be well applied to a 3D in-vitro culture model of tumor cells.

The invention discloses an internal-acid and external-alkali type organic-inorganic hybrid molecular sieve catalyst as well as a preparation method and application thereof, and belongs to the technical field of heterogeneous catalytic materials and chemical processes. According to the catalyst, a hydrogen type Beta molecular sieve is used as an acidic inner core, polyvinylpyrrolidone (PVP) is used as an organic shell, and a unique inner-acid outer-alkali structure is formed. The preparation method comprises the following steps: hydrothermally synthesizing a hydrogen type Beta molecular sieve with a specific silica-alumina ratio, and then coating PVP through surface adsorption. The catalyst is used for catalyzing the condensation of methylal and trioxymethylene under mild conditions (40-70 DEG C and normal pressure) to prepare polyoxymethylene dimethyl ethers (DMMn). The PVP shell covers acidic sites on the outer surface of the molecular sieve to form an external neutral / weak base and internal strong acid microenvironment, so that the secondary side reaction of the product is effectively inhibited, the trioxymethylene conversion rate of more than 98% and the DMMn selectivity of more than 96% can be obtained in the reaction at 50 DEG C and normal pressure, the product distribution can be regulated and controlled, and the traditional Anderson-Schulz-Flory distribution limitation is broken through. The catalyst disclosed by the invention has the advantages of high activity, high selectivity, mild conditions and easiness in separation, and has a good industrial application prospect.

The invention relates to the field of cables, and discloses a flame-retardant impact-resistant cable and a preparation process thereof.The cable sheath layer is prepared from low-density polyethylene, nitrile rubber, ethylene-vinyl acetate copolymer, modified halloysite nanotubes and a flame-retardant additive, the preparation method comprises the following steps: carrying out acylating chlorination on 2, 4-dihydroxyphenyl)-2H-benzotriazole, reacting with 3, 5-di-tert-butyl-4-hydroxybenzylamine to prepare a modified acylating chlorination ultraviolet absorbent, and grafting the modified acylating chlorination ultraviolet absorbent with aminated halloysite nanotubes to prepare the ultraviolet absorbent. The aminated halloysite nanotube is prepared by using gamma-aminopropyl triethoxy silane to modify the aminated halloysite nanotube; the flame-retardant additive is prepared from a flame-retardant intermediate obtained by reaction of diphenyl silanediol and phosphorus oxychloride and phosphonitrilic chloride trimer through a precipitation polymerization method. The added modified halloysite nanotube and flame-retardant additive can endow the cable with excellent mechanical properties, aging resistance, flame retardance and heat resistance.