230 results about "Fe3o4 nanoparticles" patented technology

The invention provides a modified basalt fiber, a basalt fiber shielding material and a preparation method, and relates to the technical field of fiber composites.The modified basalt fiber comprises an activated basalt fiber, an adhesion layer and an electromagnetic shielding layer, and the surface of the activated basalt fiber is sequentially coated with the adhesion layer and the electromagnetic shielding layer; the adhesion layer comprises polydopamine; the electromagnetic shielding layer comprises magnetic Fe3O4 nano particles and a graphene nano sheet; the mass ratio of the activated basalt fibers to the polydopamine to the magnetic Fe3O4 nanoparticles to the graphene nanosheets is 1 to (0.4 to 0.5) to (0.6 to 1) to (0.1 to 0.25). According to the basalt fiber shielding material provided by the invention, the conductive particles and the magnetic particles are combined, and by optimizing the material components and proportion, a very good electromagnetic wave absorption and shielding effect can be achieved, a wider frequency band shielding effect can be provided, and electromagnetic radiation in various frequency ranges can be effectively covered.

The invention discloses a flexible heat-conducting composite material with chain-shaped boron nitride and a preparation method, and belongs to the technical field of flexible electronic device heat management materials, the flexible heat-conducting composite material comprises an elastomer matrix and a magnetic functionalized boron nitride filler filled in the elastomer matrix; the elastomer matrix is polydimethylsiloxane; the magnetic functionalized boron nitride filler is prepared by modifying Fe3O4 nanoparticles on the surface of a boron nitride sheet; the boron nitride sheets form a vertically arranged chain structure in the elastomer matrix. The chained vertical arrangement of the boron nitride sheets is realized by prolonging the magnetic field treatment time, the Fe3O4 modification quantity is controlled to optimize the balance between the magnetic responsiveness and the heat-conducting property, a chained heat-conducting network connected end to end is formed, and the thermal seepage threshold value is reduced. According to the flexible composite material and the preparation method thereof, boron nitride sheets are induced to be vertically arranged through a magnetic field to form a chain-shaped heat-conducting network, so that high heat conductivity under low filler loading capacity is realized, and excellent stretchability is kept at the same time.

The invention discloses a preparation method of Fe3O4 magnetic nanoparticles rich in carboxyl groups on the surface, which comprises the following steps: modifying Fe3O4 nanoparticles by using polyethylene glycol and silicon dioxide to enhance the dispersity and biocompatibility of the magnetic nanoparticles, modifying the surfaces of PEG-Fe3O4 coated SiO2 nanoparticles by using a silane coupling agent containing silane groups and unsaturated double bonds to obtain the magnetic nanoparticles rich in carboxyl groups on the surface, and modifying the magnetic nanoparticles rich in carboxyl groups on the surface by using a silane coupling agent containing silane groups and unsaturated double bonds to obtain the magnetic nanoparticles rich in carboxyl groups on the surface. Then octavinyl-POSS and double bonds on the surfaces of the nano particles are subjected to click modification to form an octahedral cage, 4-mercaptobenzoic acid and double bonds are further subjected to click modification, the surfaces of the nano particles are rich in carboxyl, and a polymer brush rich in carboxyl is constructed. Compared with a conventional streptavidin coupling method, a high-density polymer chain provides a large number of carboxyl active binding sites, so that the streptavidin coupling amount is increased, the antibody coupling rate is increased, and a solution is provided for applications such as high-sensitivity biological detection, efficient targeted drug delivery and stable immunoassay.

The invention provides application of Fe3O4 nanoparticles in preparation of a medicine for treating benign prostatic hyperplasia, and relates to the technical field of biological medicines. The invention further discloses application of the Fe3O4 nano-particles in preparation of a medicine for treating benign prostatic hyperplasia. The research result of the invention emphasizes that the ferroferric oxide nanoparticles are a promising candidate drug for targeted therapy of BPH and related prostate diseases, and new possibility is provided for treatment intervention of urinary surgery. The inventor studies the effect of the Fe3O4 nanoparticles in inhibiting benign prostatic hyperplasia. Results of the inventor show that the nanoparticles not only effectively reduce the proliferation rate of prostate cells, but also improve related biochemical indexes. Therefore, the polypeptide has potential application in treatment of prostatic hyperplasia.

The present invention discloses a basalt fiber reinforced thermoplastic composite material with electromagnetic wave shielding function and its preparation method. The composite material is prepared by melt blending basalt short fibers after surface modification and thermoplastic plastics in a certain proportion. The preparation method of the surface-modified basalt short fibers is as follows: The basalt fibers, surface lipophilized modified Fe3O4 nanoparticles, carbon nanotubes or graphene nanosheets, and dopamine that have undergone surface cleaning treatment are dispersed in a buffer solution for polymerization reaction, and a polydopamine / Fe3O4 nanoparticle composite coating layer is formed on the surface of the basalt fibers, and at the same time, carbon nanotubes or graphene nanosheets are adhered to its surface. The composite material of the present invention not only obtains more excellent mechanical strength, but also has electromagnetic wave shielding function at the same time.

The application relates to a method for one-step synthesis of strong magnetic hydrophobic Fe3O4 nanoparticles at low temperature and the Fe3O4 nanoparticles and application, and belongs to the technical field of nano material preparation. The method comprises the following steps: adding a ferrous sulfate solution into a mixed solution of sodium hydroxide and sodium nitrate, heating and stirring to react, adding oleic acid in the reaction process, and obtaining black Fe3O4 crystals after the reaction is completed. The saturation magnetization of the obtained strong magnetic hydrophobic Fe3O4 nanoparticles can reach 85.69 emu / g at most, and the water contact angle can reach 148.95 DEG. The one-step synthesis reaction only needs to use oleic acid as a regulator, avoids an extreme high-temperature and high-pressure environment, does not need to use a toxic chemical solvent, the condition is mild, the process is simple, the operation condition is easy to control, and the method has a wide application prospect.

The invention relates to a method for preparing an efficient electromagnetic shielding graphene film by using a rapid Joule heat technology, and belongs to the technical field of functional materials and application thereof. The method comprises the following steps: firstly, preparing a graphene oxide film through vacuum filtration, then carrying out pre-reduction treatment under the protection of argon, heating the film to 700 DEG C, and carrying out heat preservation for 1 hour so as to remove part of oxygen functional groups; and then, soaking the pre-reduced film in a ferric chloride ethanol solution, introducing a Fe3O4 nanoparticle precursor, and carrying out discharge treatment for 0.1 second under the voltage of 100V through a rapid Joule thermal reduction technology to realize rapid reduction of graphene oxide and doping of Fe3O4 nanoparticles. The finally prepared graphene film shows excellent electromagnetic shielding effectiveness in an X wave band (8-12 GHz), the electromagnetic shielding effectiveness reaches 38 dB, and the electromagnetic shielding effectiveness is improved by 2 dB compared with a sample (36 dB) not doped with Fe3O4. The method has the advantages of being easy and convenient to operate, low in energy consumption and high in reduction efficiency, meanwhile, the synergistic effect of conductivity loss, magnetic loss and dielectric loss is achieved through introduction of the Fe3O4 nanoparticles, the electromagnetic shielding performance of the material is remarkably improved, and the method is suitable for the fields of electromagnetic interference protection of electronic equipment and the like.

The invention belongs to the technical field of biomedical materials, and discloses pH-responsive injectable hydrogel as well as a preparation method and application thereof. Comprising the following steps: (1) dissolving sodium alginate in water to form a uniform solution; (2) adding a fat-soluble small molecule drug and Fe3O4 nanoparticles into the solution, carrying out high-speed shearing dispersion under an ice-water bath condition to form a drug / nano composite system, and standing; and (3) sequentially adding a calcium carbonate suspension and glucolactone into the drug / nano composite system, uniformly stirring, and incubating until the mixture is completely cured to obtain the pH-responsive injectable hydrogel. The hydrogel obtained by the invention not only has excellent injectability and pH response release performance, but also can remarkably improve the loading efficiency of fat-soluble drugs, and provides a new technical approach for realizing local anti-tumor treatment.

The invention relates to the field of soil remediation materials, in particular to a nano-enzyme composite material, a preparation method of the nano-enzyme composite material and application of the nano-enzyme composite material in remediation of organic chemical pesticide pollution of soil, and the preparation method of the nano-enzyme composite material comprises the following steps: S1, sequentially coating the surfaces of Fe3O4 nano particles with a compact SiO2 layer and a mesoporous SiO2 layer to form an SFe3O4atMSN composite material; s2, the surfaces of the CaO2 nanoparticles are coated with a compact SiO2 layer, and an SCaO2 composite material is formed; s3, preparing a chitosan ferrous complex solution Cs-Fe, and uniformly dispersing the SFe3O4 (at) MSN composite material in the Cs-Fe solution to form a dispersion liquid containing the SFe3O4 (at) MSN (at) Cs-Fe composite material; and S4, adjusting the pH value of the dispersion liquid containing the SFe3O4 (at) MSN (at) Cs-Fe composite material to 7-10, and dispersing SCaO2 in the solution to obtain the SFe3O4 (at) MSN (at) SCaO2 (at) Cs-Fe. The nano-enzyme composite material disclosed by the invention is applied to acid soil, and organic chemical pesticide pollutants in the acid soil can be effectively degraded.

The invention relates to the technical field of biological medicine, in particular to a diagnosis and treatment integrated brain-targeted magnetic particle imaging tracer and a preparation method and application thereof. The preparation method comprises the following steps: loading tetrahydrocurcumin into glucan by adopting a nano-particle self-assembly technology to form glucan nano-particles loaded with tetrahydrocurcumin, synthesizing Fe3O4 nano-particles by adopting a chemical precipitation method, and embedding the Fe3O4 nano-particles on the glucan nano-particles to obtain the diagnosis and treatment integrated brain-targeted magnetic particle imaging tracer agent. The nano-particles are marked as THC (at) Dex-Fe3O4 nano-particles. The THC-Dex-Fe3O4 nanoparticles play a role in treating the Alzheimer's disease during brain imaging diagnosis, and the technical problems that magnetic particle imaging cannot be applied to diagnosis of the Alzheimer's disease and the Alzheimer's disease is difficult to treat are solved.

The invention belongs to the technical field of SERS (Surface Enhanced Raman Scattering) detection, and relates to a preparation method of an Ag-Fe3O4 composite SERS substrate and application of the Ag-Fe3O4 composite SERS substrate in monitoring trace pollutants in water. Based on a plasma-semiconductor synergistic enhancement mechanism, cubic Fe3O4 nano particles with exposed {100} crystal faces are synthesized through a hydrothermal method, and the cubic Fe3O4 nano particles and Ag nano particles are subjected to ultrasonic-stirring to construct the Schottky heterojunction. The substrate creatively realizes dual-channel enhancement: the local surface plasmon resonance effect of Ag nanoparticles generates electromagnetic enhancement, the narrow band gap of Fe3O4 promotes photo-induced electrons to be transferred to Ag, an interface electric field is formed, and the polarizability of adsorption molecules is remarkably increased. When the probe is applied to detection of trace pollutants in a water body, the probe molecule RB is anchored on the surface of Fe3O4 through carboxyl, and the HOMO energy level of the probe molecule RB and the valence band top of Fe3O4 generate resonance charge transfer, so that the Raman cross section is improved. The detection limit of RB under 0.25 mW laser is increased by several orders of magnitude compared with that of a single Ag substrate.

The invention relates to the technical field of biochemistry, in particular to a specific affinity enrichment and preparation method of a torreya grandis protease hydrolysate ACE inhibitory peptide, which comprises the following steps: step 1, preparing and characterizing magnetic aminated Fe3O4 nanoparticles; step 2, preparing and characterizing the immobilized trypsin; 3, preparing and characterizing the immobilized ACE, and optimizing reaction conditions; step 4, determining the activity of the immobilized ACE; step 5, then preparing and specifically enriching the Chinese torreya antihypertensive peptide; step 6, then, carrying out molecular docking through AutoDock Vina; according to the method, genipin is adopted as a cross-linking agent, magnetic Fe3O4 nanoparticles with the ACE inhibitory peptide specific affinity recognition function are constructed, specific enrichment of the ACE inhibitory peptide from the torreya grandis cake protein hydrolysate is achieved, and specific separation is achieved.

The invention discloses terahertz wave-absorbing foam based on magnetically-induced gradient distribution carbon nanotubes and a preparation method, and belongs to the technical field of photoelectric materials and devices. The terahertz wave-absorbing foam comprises a porous framework and a wave-absorbing agent distributed in the porous framework, wherein the porous skeleton is a PDMS matrix with holes, the wave-absorbing agent is MWCNT modified by Fe3O4 nanoparticles, and the mass percentage of the wave-absorbing agent in the wave-absorbing foam is 3-7wt%. The dielectric constant of the wave-absorbing foam is regulated and controlled by controlling the concentration of the MWCNT modified by the Fe3O4 nanoparticles, and the concentration of the MWCNT can be guided to be distributed in a longitudinal gradient manner by using an external magnetic field, so that surface electromagnetic impedance matching is realized, and finally reflection suppression and absorption enhancement of electromagnetic waves are completed; meanwhile, large-area preparation can be realized by using white granulated sugar as a sacrificial template, and the method is suitable for industrial production.

The invention belongs to the technical field of biological materials, and discloses a pH response type magnetic hierarchical porous MOFs composite material and a preparation method thereof, the composite material is formed by emulsifying and cross-linking magnetic MOFs composite nanospheres with Fe3O4 nanoparticles as a core and an MOFs layer as a shell, and the composite material is of a cluster structure. According to the hierarchical porous structure of the composite material, the pore diameter is increased, the specific surface area of MOFs is increased, the yield of protein can be increased, and the application efficiency is improved; the method can be used for protein enrichment and release.

The invention relates to the technical field of oil gas well tracing monitoring, in particular to a preparation method and application of an oil gas well tracing monitoring magnetic nano tracer agent. Comprising the following steps: dissolving FeCl3, FeSO4. 7H2O and doped metal salt in water, and introducing N2 to remove oxygen; the initial reaction temperature is 85 DEG C, rapidly adding ammonia water, reacting to generate Fe3O4 nanoparticles, doping elements, reducing the temperature to 60 DEG C, and firstly adding sodium citrate for primary carboxyl modification; adding a mixed solution of oleic acid and PEG twice; the pH value of the reaction system is controlled to be 9.5-10.5 in the whole process. The method has the beneficial effects that the doping amount is remarkably increased, the doping amount of doped elements is multiple times of that in the prior art, and the detection sensitivity is remarkably improved; in addition, oleic acid / PEG composite modification is adopted instead of single citric acid modification, so that the tracer is kept stably dispersed in high-salinity formation water; the superparamagnetism facilitates magnetic separation and recovery, and is suitable for harsh formation conditions.

The invention discloses a magnetic-aptamer targeting tumor tissue nano-drug delivery system as well as a preparation method and application thereof, and belongs to the field of medicines. The system comprises a mesoporous ferroferric oxide magnetic core, a polyethyleneimine (PEI) layer coated outside the mesoporous ferroferric oxide magnetic core and an aptamer adsorbed outside the PEI layer, and an autophagy activator can be selectively loaded in the mesoporous core. The preparation method comprises the following steps: sequentially carrying out drug loading, PEI coating and aptamer modification on the mesoporous Fe3O4 nanoparticles. According to the invention, efficient enrichment and endocytosis of tumor tissues are realized through dual effects of magnetic targeting and active targeting of the aptamer; lysosome escape is promoted by using the proton sponge effect of PEI; finally, by virtue of the synergistic effect of iron ions released by degradation of the Fe3O4 nanoparticles and endogenous iron ions released by ferritin autophagy induced by an autophagy activator, ferroptosis of tumor cells is induced through enhanced Fenton-like reaction, so that high-efficiency and low-toxicity targeted therapy is realized.

The invention relates to liquid metal-based dual-network magnetic hydrogel as well as a preparation method and application thereof. The hydrogel comprises dual-network hydrogel and magnetic Fe3O4 nanoparticles loaded in a network structure of the dual-network hydrogel, the double-network hydrogel comprises a first network structure and a second network structure, wherein the first network structure is a network structure formed by polymerizing a liquid metal coated sodium alginate chain, and the second network structure is a polyacrylamide network structure formed by polymerizing an acrylamide monomer; the mass ratio of the liquid metal to the magnetic Fe3O4 nanoparticles is (0.5-2): (0.5-1.0). Compared with the prior art, the composite hydrogel not only can effectively shield electromagnetic radiation, but also has good intelligent magnetic responsiveness, and the application prospect of the composite hydrogel in the fields of intelligent materials, sensors, electromagnetic shielding and the like is widened.

This invention belongs to the field of tertiary oil recovery technology, specifically relating to a CO2-switched magnetically driven nanoparticle, its preparation method, and its application. The magnetically driven nanoparticles are silica-coated Fe3O4 nanoparticles. The surface of the silica coating is further modified with amidine groups to act as CO2 switches. These CO2 switches cause the hydrophilicity of the magnetically driven nanoparticles to increase with the increase of CO2 solubility in the solution in which they are located. This invention integrates emulsification and demulsification functions through the CO2 switch loaded on the surface of the magnetically driven nanoparticles. Furthermore, the particles can be recycled using their own magnetic response, reducing costs. This nano-displacement agent can solve the problems of poor efficiency, ineffective oil-water separation, high economic costs, and environmental impact associated with existing displacement agents.

The invention discloses an anti-biofilm nano composite material added with resveratrol and a preparation method of the anti-biofilm nano composite material. According to the method, ferric trichloride hexahydrate, trisodium citrate, sodium acetate, polyetherimide, resveratrol and hyaluronic acid are used as raw materials, modified magnetic Fe3O4 nanoparticles with positive charges are prepared through a hydrothermal method, carbon dots derived from a resveratrol and hyaluronic acid mixture are introduced, and the magnetic Fe3O4 nanoparticles with positive charges are prepared. The anti-biofilm nano composite material added with the resveratrol is prepared. The nano composite material disclosed by the invention can be attached to a biological membrane, so that the loss is reduced in a transfer process, the effective utilization rate of a medicine is remarkably improved, and excellent magnetic property, antibacterial property and biological membrane resistance are shown.

The invention relates to a construction method and application of a ternary composite photocatalyst, and the construction method comprises the following steps: step 1, synthesizing Bi2MoO6: taking Bi (NO3) 3.5 H2O and Na2MoO4. 2H2O as precursors, reacting for 12 hours at 180 DEG C by adopting a hydrothermal method, and centrifugally washing and drying to obtain Bi2MoO6 powder; step 2, loading Fe3O4 nanoparticles on the surface of Bi2MoO6 to form a composite core-shell structure: mixing FeCl3. 6H2O, FeCl2. 4H2O and the Bi2MoO6 powder obtained in the step 1, heating to 80 DEG C under the protection of nitrogen, adding a NaOH solution to adjust the pH value to 10, and reacting for 1 hour to form a Fe3O4 / Bi2MoO6 core-shell structure composite material; step 3, anchoring Ag nano-particles: dispersing the Fe3O4 / Bi2MoO6 composite material obtained in the step 2 in water, adding an AgNO3 solution, stirring in a dark place, and then anchoring Ag nano-particles on a xenon lamp (lambda gt; and reducing Ag < + > into Ag0 under the irradiation of SiO2 / Bi2MoO6, thereby obtaining the Fe3O4 / Bi2MoO6 / Ag composite photocatalyst. The Fe3O4 / Bi2MoO6 / Ag composite photocatalyst is a novel Fe3O4 / Bi2MoO6 / Ag composite photocatalyst, light absorption is enhanced through plasma resonance, carrier separation is promoted through heterojunction, magnetic recovery of Fe3O4 is achieved, and the bottleneck is solved.

The present invention provides a magnetothermal dual-responsive green nanoemulsifier and a preparation method thereof, belonging to the technical field of emulsifiers. The preparation method comprises the following steps: S1. preparing Fe3O4 nanoparticles; S2. preparing Fe3O4@SiO2 nanoparticles; S3. preparing Fe3O4@SiO2@NH2 nanoparticles; S4. preparing Fe3O4@SiO2@Br nanoparticles; and S5. preparing Fe3O4@SiO2@PNIPAM nanoparticles, which are the magnetothermal dual-responsive green nanoemulsifier. The preparation method of the present invention is simple and controllable, with a short cycle time. The resulting nanoemulsifier has good emulsification effect, high stability, and is environmentally friendly. It has efficient magnetothermal responsiveness and can be recycled and reused.

The invention discloses a preparation method of a magnetically-driven diatom cell micron robot based on natural diatom shells and a photodynamic therapy method of the magnetically-driven diatom cell micron robot. The method comprises the following steps: firstly, centrifugally enriching a diatom suspension, treating the diatom suspension in a 0.1 M HCl darkroom for 4 hours, removing surface calcium and exposing a porous structure; and carrying out shaking table resonance with positively charged Fe3O4 nanoparticles (300 [mu] g / mL) for 1.5 h, uniformly modifying the magnetic particles on the surface of the shell through electrostatic adsorption, centrifuging, washing, and freeze-drying at-80 DEG C to obtain the Mag-Diatom. The prepared Mag-Diatom not only retains the autofluorescence of natural chlorophyll in diatom and the capability of generating active oxygen through laser triggering, but also can realize directional control and rapid separation in an external magnetic field due to superparamagnetic response of Fe3O4 modification. The invention provides a controllable and directional micro-nano robot PDT platform which has good biocompatibility and a wide clinical application prospect.

The application relates to the technical field of photocatalysts, in particular to a Fe3O4 / P / CuO x Nano-array composite photocatalyst, preparation method and application thereof. The preparation method is as follows: S1, a copper base material with CuO x nano-arrays is prepared; S2, the copper base material obtained in step S1 is immersed in a protective layer growth solution, the base material is taken out after reaction, and then washed and dried; the protective layer growth solution is prepared from one or more of dopamine mixed solution, tannic acid mixed solution and tea polyphenol mixed solution; S3, the base material obtained in step S2 is immersed in Fe3O4 nanoparticle dispersion liquid for a period of time, and then washed and dried after being taken out, so that the composite photocatalyst is prepared. Under visible light irradiation, the adsorption rate of the application to Cr(VI) reaches more than 98%, the proportion of elemental Cr in the reduction product is more than 60%, and the decomposition rate of the antibiotic reaches more than 99%.

The application belongs to the technical field of medicine preparation, and particularly relates to a magnetic layered double hydroxide, a targeted drug-loaded nano preparation, a preparation method and application of a tumor-targeted drug-loaded nano preparation. The preparation method of the magnetic layered double hydroxide provided by the application can prepare Fe3O4 nanoparticles with small particle size, and further prepare the magnetic layered double hydroxide which can be used as a water-soluble drug carrier. The magnetic layered double hydroxide is used for preparing the targeted drug-loaded nano preparation and the tumor-targeted drug-loaded nano preparation, and can be used for delivering water-soluble drugs such as 5-fluorouracil. The tumor-targeted drug-loaded nano preparation has good dispersity and can be actively targeted to HepG2 cells with high FR expression, has a good inhibitory effect on liver cancer cells, and is expected to provide a potential new treatment system for magnetic chemotherapy.

The invention discloses a three-dimensional network structure magnetic fiber carrier reinforced micro-plastic magnetic separation removal method, which is characterized in that Fe3O4 nanoparticles are selectively precipitated among sepiolite fiber bundle layers by controlling a coprecipitation process, and a wedging effect is generated to realize controllable stripping of fiber bundles, so that a three-dimensional network structure magnetic carrier is formed; a mechanical interlocking structure is formed on the surface of the flexible fiber and the micro-plastic, and the pH of a water body is self-adaptively regulated and controlled through the amphoteric ionization characteristic of silicon hydroxyl; enabling the magnetic aggregate suspension to sequentially pass through a multi-stage gradient magnetic field consisting of a pre-magnetization field, a main separation field and a fine scavenging field, and controlling the flow rate to enable the aggregate to form a stable filter cake layer on the surface of a magnetism gathering medium, so as to realize efficient separation of the micro-plastic; and the magnetic gathering medium capturing the aggregate is subjected to heat treatment, so that the micro-plastic is thermally decomposed, the magnetic carrier is directly recycled, the magnetic performance is improved, and regeneration reinforcement is realized. The micro-plastic removal rate reaches 99% or above, the performance is stable after multiple cycles, and the method is suitable for treating various micro-plastic-containing water bodies.

This invention relates to a high-temperature resistant industrial coating and its preparation method. The method includes: amylating Fe3O4 nanoparticles; grafting the amylated Fe3O4 nanoparticles with polybenzimidazole to obtain PBI-g-Fe3O4 composite particles; in-situ growing MOF to form polyMOF; and surface modification with a hydrophilic silane coupling agent to obtain a hydrophilic modified polyMOF; simultaneously, co-grafting silica nanoparticles with an aminosilane coupling agent and a long-chain alkylsilane coupling agent to obtain a synergist; finally, dispersing all components in an aqueous polyester resin varnish to prepare a composite coating. This invention achieves stable dispersion and strong interfacial bonding of polyMOF in aqueous polyester through a multi-level chemical bonding structure. The synergist synergistically provides curing and defoaming effects. The resulting coating exhibits grade 0 adhesion, excellent defoaming performance, a pencil hardness of 3H, and a temperature resistance limit of 640℃, showing broad application prospects in the field of high-temperature protection.

The invention belongs to the technical field of magnetic composite materials and analysis and detection, and particularly relates to a magnetic cation covalent organic framework material as well as a preparation method and application thereof, and the preparation method comprises the following steps: taking trialdehyde phloroglucinol and bromomethanthridine as monomers, and carrying out aldehyde amine condensation polymerization on the surfaces of Fe3O4 nanoparticles to obtain the magnetic cation covalent organic framework material. Based on the magnetic cation covalent organic framework material, a magnetic solid phase extraction-liquid chromatography-mass spectrometry detection method is established, and efficient enrichment and sensitive detection of phenoxy carboxylic acid herbicides can be realized. The magnetic cation covalent organic framework material has the advantages of simplicity and convenience in preparation, high enrichment efficiency, strong selectivity, good reusability and the like. The constructed detection method is rapid, sensitive and accurate, can meet the trace analysis requirements of phenoxy carboxylic acid herbicides in water, and has very strong practicability.

The invention relates to the technical field of enzymatic hydrolysis, and particularly to an enzymatic hydrolysis preparation method for low-molecular-weight heparin sodium. The method comprises the following steps: S1.1, pre-treating the sodium heparin and combining it with a protective agent to obtain a heparin complex precipitate; S1.2, performing a first enzymatic hydrolysis on the heparin complex precipitate to obtain a supernatant A and a precipitate; S1.3, adjusting the pH of the precipitate to release highly sulfated fragments to obtain a supernatant B; S1.4, performing a second enzymatic hydrolysis on the supernatant B to obtain a secondary enzymatic hydrolyzate, combining the supernatant A and the secondary enzymatic hydrolyzate, and filtering to obtain a retentate; S1.5, post-treating the retentate to obtain the low-molecular-weight heparin sodium; and using a composite protective agent prepared by covalently coupling citric acid-modified superparamagnetic Fe3O4 nanoparticles with aminocalixarene, accurately regulating the enzymatic hydrolysis path and achieving efficient separation, thereby solving the problems of uneven molecular weight, low yield, and complex purification in traditional processes.

The invention discloses a surface modified titanium stent with a magnetic hydrogel coating and a preparation method and application of the surface modified titanium stent, and belongs to the technical field of biomedical materials. The surface modified titanium scaffold with the magnetic hydrogel coating comprises a titanium substrate, a polydopamine coating and a hydrogel precursor solution coating, wherein the polydopamine coating and the hydrogel precursor solution coating are compounded on the titanium substrate; the polydopamine coating is positioned between the titanium substrate and the hydrogel precursor solution coating; the hydrogel precursor solution is prepared from freeze-dried GelMA, Fe3O4 nanoparticles and ammonium persulfate. The prepared surface modified titanium scaffold with the magnetic hydrogel coating has excellent mechanical properties and stability, and can improve the ALP activity level of cells, improve the collagen secretion level and promote mineralization in the stem cell osteogenic differentiation process through an external magnetic field with certain strength, so that the bone regeneration process is accelerated, and the osteogenic differentiation effect is improved. The method has a wide application prospect in preparation of bone graft materials and bone repair materials.

The application discloses a recyclable Fe3O4 polymer nanocomposite pour point depressant, a preparation method and application thereof, and belongs to the technical field of crude oil pour point and viscosity reduction. The preparation method of the Fe3O4 polymer nanocomposite pour point depressant comprises the following steps: (1) preparing hydrophobic Fe3O4 nanoparticles by using a coprecipitation method; (2) performing a free radical polymerization reaction on the hydrophobic Fe3O4 nanoparticles and grafting materials to obtain polymer-modified magnetic nanoparticles; and (3) dispersing the polymer-modified magnetic nanoparticles and ethylene-vinyl acetate copolymer in an organic solvent to obtain the Fe3O4 polymer nanocomposite pour point depressant. The prepared composite pour point depressant can effectively improve the low-temperature fluidity of crude oil, can be recycled, and reduces the refining cost of crude oil and the preparation cost of the reagent.