37 results about "Ferromagnetic nanoparticles" patented technology

A magnetic nanoparticle (22), a magnetic nanomaterial (30), assembly (30), and a method for synthsising a magnetic nanoparticle, relating to thermodynamically stable and air stable ferromagnetic nanoparticles of adjustable aspect ratio made upon decomposition of organometallic precursors in solution in the presence of a reaction gas and a mixture of organic ligands. The magnetic nanomaterial comprises magnetic nanoparticles of homogeneous size, shape, and magnetic orientation that comprises a magnetic core (24, 34) ferromagnetic at room temerature and / or operating temperatures, and a non-magnetic matrix (26, 36) encapsulating the magnetic core. This magenetic nanomaterial could be used in high frequency integrated circuit applications, such as used in wireless portable electronic devices, to enchance magnetic field confienment and improve passive component performance at MHz and GHz frequency in a variety of passive and active devices, such as transformers, on-chip signal isolation, inductors, and the like.

Provided is a method of inhibiting magnetically induced aggregation of ferrimagnetic and / or ferromagnetic nanoparticles by encapsulating the nanoparticles in a silica shell. The method entails coating magnetic nanoparticle surfaces with a polyacid polymer to form polymer-coated magnetic nanoparticles and treating the polymer-coated magnetic nanoparticles with a silica precursor to form uniform silica-coated magnetic nanoparticles. By controlling the thickness of the silica encapsulating the nanoparticles, the inherent magnetically induced aggregation of the nanoparticles can be completely inhibited.

A magnetic recording medium for high-density recording, having a doped interlayer to preserve the uniformity and ordering of the magnetic nanoparticles in its recording layer. The interlayer is doped with a high electronegativity material. The dopant atoms in the interlayer interact with the ferromagnetic nanoparticles to promote the formation of a homogeneous, ordered monolayer of nanoparticles in the recording layer. In addition, the high electronegative property of the dopant atoms holds the nanoparticles in place during the subsequent annealing process to prevent sintering and disordering damage. In one embodiment, the dopant is a halogen or non-halogen material having a high electronegativity, which is not polymerized to the matrix material in the interlayer. The matrix material may be polymerized. An example of a doped interlayer is a fluorinated carbon film.

This invention relates to a new type of reflective optical element made of a fluid that responds to a force if subjected to a magnetic field. As a consequence, one can impose any shape one wants to the reflecting surface by generating an appropriate magnetic field geometry with permanent magnets, electromagnets or a combination of permanent magnets and electromagnets, or the like. A preferred embodiment uses a ferromagnetic fluid made of water containing ferromagnetic nanoparticles. Liquid ferromagnetic surfaces thus obtained were successfully shaped using magnetic fields. In another preferred embodiment, to modify the reflectivity of the optical element, a reflective layer, such as a nano-engineered silver reflecting surface, is deposited on the surface of the magnetically sensitive fluid. The surface of the reflecting layer can therefore be warped by applying a magnetic field to the fluid. Coated or uncoated magnetically deformable liquid surfaces with reflective layers allows one to make inexpensive and versatile high-quality reflecting mirrors having complex shapes. The shapes of the reflecting surfaces can be changed within short time periods by changing the shapes of the magnetic fields.

This invention relates to a new type of reflective optical element made of a fluid that responds to a force if subjected to a magnetic field. As a consequence, one can impose any shape one wants to the reflecting surface by generating an appropriate magnetic field geometry with permanent magnets, electromagnets or a combination of permanent magnets and electromagnets, or the like. A preferred embodiment uses a ferromagnetic fluid made of water containing ferromagnetic nanoparticles. Liquid ferromagnetic surfaces thus obtained were successfully shaped using magnetic fields. In another preferred embodiment, to modify the reflectivity of the optical element, a reflective layer, such as a nano-engineered silver reflecting surface, is deposited on the surface of the magnetically sensitive fluid. The surface of the reflecting layer can therefore be warped by applying a magnetic field to the fluid. Coated or uncoated magnetically deformable liquid surfaces with reflective layers allows one to make inexpensive and versatile high-quality reflecting mirrors having complex shapes. The shapes of the reflecting surfaces can be changed within short time periods by changing the shapes of the magnetic fields.

The present invention provides a synthetic antiferromagnetic (SAF) nanoparticle. The SAF nanoparticle includes at least two ferromagnetic layers and at least one non-magnetic spacer layer. The spacer layer is situated in between planar surfaces of the ferromagnetic layers. The saturation field of the SAF nanoparticle is tunable by the geometry and composition of the nanoparticle. Preferably, the saturation field can be tuned to be between about 100 Oe and about 10,000 Oe. Also preferably, the SAF nanoparticle has a magnetic moment of at least 800 emu / cm3. In a preferred embodiment, the SAF nanoparticle has at least one of a biomolecule, a recognition moiety, or a molecular coating attached to its surface. The SAF nanoparticle may also have a dye attached to its surface.

Provided is a method of inhibiting magnetically induced aggregation of ferrimagnetic and / or ferromagnetic nanoparticles by encapsulating the nanoparticles in a silica shell. The method entails coating magnetic nanoparticle surfaces with a polyacid polymer to form polymer-coated magnetic nanoparticles and treating the polymer-coated magnetic nanoparticles with a silica precursor to form uniform silica-coated magnetic nanoparticles. By controlling the thickness of the silica encapsulating the nanoparticles, the inherent magnetically induced aggregation of the nanoparticles can be completely inhibited.

The present invention relates to a water-soluble polymer complex that includes a water-soluble block copolymer and a magnetic nanoparticle, wherein the water-soluble polymer complex has a nonzero net magnetic moment in the absence of an applied magnetic field at ambient temperatures. The water-soluble block copolymer is preferably a diblock or triblock copolymer and the magnetic nanoparticle is preferably a ferrimagnetic or ferromagnetic nanoparticle. The water-soluble complexes may be derivatized with reactive groups and conjugated to biomolecules. Exemplary water-soluble polymer complexes covered under the scope of the invention include PEG112-b-PAA40 modified CoFe2O4; NH2-PEG112-b-PAA40 modified CoFe2O4; PNIPAM68-b-PAA28 modified CoFe2O4; and mPEG-b-PCL-b-PAA modified CoFe2O4.

The present disclosure provides devices, systems and methods for hyperthermia cancer treatment by supplying ferromagnetic nanoparticles to a target area having or suspected of having cancer cells, the ferromagnetic nanoparticles are configured to attach to the cancer cells and heat by absorbing magnetic energy, and radiating the target area with microwaves such that the target area is within a nearfield range of the radiated microwave, and the microwave radiation nearfield is magnetically biased such that the ratio of magnetic energy to electric energy is greater than 1.

An encoded microparticle having a spatial code is provided; and a set of encoded microparticles possessing subsets each provided with a distinguishable spatial code, wherein the codes comply with a pre-determined coding scheme. Presented are also methods of using the encoded microparticles in various biological assays, such as various multiplex assays and visualizing them by creating a digital image of the encoded microparticles and determining whether false positives are present. Further are provided methods of manufacture of the encoded microparticles which employ ferromagnetic nanoparticles applied using spin-on-glass techniques.

An information recording apparatus comprises a plurality of fine particles forming an array on a plane in close proximity of each other, each of the plural particles including a ferromagnetic metal, a light-emitting device for exciting a near-field light, and a photo-electric conversion element for detecting a near-field light traveled along the fine particles.

The invention belongs to the technical field of environmental pollution research and environmental protection technology, and in particular relates to a ferromagnetic nanoparticle and preparation thereof and an application in removal of micro-plastics in the environment based on the nanoparticle. The surface of an iron nanoparticle is modified with methoxysilane to form siloxane bonds (-Si-O-Si-), and alkyl chains face outward to form a hydrophobic iron nanoparticle. The ferromagnetic nanomaterial is applied to extract and remove micro-plastics in an environmental sample. The method has wide adaptability, reliable method, simple operation and relatively low cost, can be used for extracting and identifying micro-plastics in environmental pollution (water, soil, sediment) researches, can be used for removing micro-plastics in environmental water body, sewage, and drinking water, provides a new solution for the micro-plastic environmental pollution field research and the environmental management, and is suitable for further development and application.

The invention discloses a novel magnetic sealing material, which is formed by nucleus-shell-grafting group particles. The nucleus is ferromagnetic nanoparticles with the particle size being 5 to 100nm; the shell is an inert metal oxide layer or a resin layer covering the surface of the nucleus; hydroxide radical, carboxyl, amidogen or hydrosulphonyl on the shell can be chemically grafted with groups; the thickness of the shell is 1 to 100nm; the grafting group is a fluorocarbon chain grafted on the inert metal oxide layer or the resin layer; the cover degree of the fluorocarbon chain on the shell surface is 5 to 95 percent. The invention provides the novel magnetic sealing material used as magnetic particles in magnetic fluid, so that the magnetic particles can be directly, stably and uniformly dispersed into carrier liquid, and cannot be settled or agglomerated, and the magnetic sealing effect of the magnetic fluid is better.

A magnetic nanoparticle (22), a magnetic nanomaterial (30), assembly (30), and a method for synthsising a magnetic nanoparticle, relating to thermodynamically stable and air stable ferromagnetic nanoparticles of adjustable aspect ratio made upon decomposition of organometallic precursors in solution in the presence of a reaction gas and a mixture of organic ligands. The magnetic nanomaterial comprises magnetic nanoparticles of homogeneous size, shape, and magnetic orientation that comprises a magnetic core (24, 34) ferromagnetic at room temperature and / or operating temperatures, and a non-magnetic matrix (26, 36) encapsulating the magnetic core. This magnetic nanomaterial could be used in high frequency integrated circuit applications, such as used in wireless portable electronic devices, to enchance magnetic field confinement and improve passive component performance at MHz and GHz frequency in a variety of passive and active devices, such as transformers, on-chip signal isolation, inductors, and the like.

The invention discloses a method for preparing magnetic nanoparticles with improved quality. The method comprises the following steps: weighing a soluble trivalent iron salt and sodium acetate to be dissolved in ethylene glycol so as to obtain yellow transparent liquid; adding trisodium citrate, a polyvinylpyrrolidone dispersing agent and an alkaline additive, and mechanically stirring at a room temperature; and adding the obtained mixed liquid into a reactor to be reacted, naturally cooling the product, washing with ethanol and water, and performing vacuum drying, thereby obtaining the magnetic nanoparticles. According to the method for preparing magnetic nanoparticles disclosed by the invention, ferroferric oxide magnetic nanoparticles are synthesized by a solvothermal method, synthesisis completed at a time under high temperature and high pressure, later crystallization treatment is not needed, the obtained powder is narrow in particle size distribution and pure in components, andanhydrous sodium acetate with excellent electrostatic stability is selected as the alkaline additive, so that agglomeration of the magnetic nanoparticles is effectively avoided. Therefore, the prepared ferroferric oxide magnetic nanoparticles are excellent in stability and have excellent monodispersity, superparamagnetism and particle size uniformity in water.

A method including providing Au-doped Co nanoparticles. The nanoparticles include a combination of non-ferromagnetic nanoparticles and weakly ferromagnetic nanoparticles. The nanoparticles each have an exterior surface. The surfaces of the nanoparticles are functionalized with 7-(5-uracil-ylcarbamoyl)heptanoic acid. A polymer is provided having a general formula including a uracil group. A dispersion is formed by agitating a solution of the nanoparticles. The solution is spin cast into a film. The film is heated under vacuum at a first temperature, TFM, resulting in inducing ferromagnetism in the non-ferromagnetic nanoparticles and converting the non-ferromagnetic nanoparticles to ferromagnetic nanoparticles, and resulting in enhancing ferromagnetism in the weakly ferromagnetic nanoparticles. The nanoparticles are aligned such that magnetic easy axes of the nanoparticles are oriented by applying a magnetic field to the dispersion while at a second temperature less than TFM. The axes align in a plane parallel to a plane of the film.

The invention relates to a temperature measurement method based on ferromagnetic resonance frequency. The method comprises the following steps: applying a static magnetic field to a measured object containing a ferromagnetic nanoparticle solution to saturate and magnetize ferromagnetic nanoparticles; applying an alternating pulse excitation magnetic field along the vertical direction of the static magnetic field; determining the ferromagnetic resonance frequency of the ferromagnetic nanoparticles during ferromagnetic resonance through a frequency sweep method; and calculating the temperature of the measured object according to the determined ferromagnetic resonance frequency, wherein the calculation formula is shown in the specification: according to the method provided by the invention, the temperature is measured through the constructed relation model of the ferromagnetic resonance frequency and the temperature, the model is simple in form, the measurement method is simple and convenient, the internal temperature of the measured object can be rapidly and conveniently measured, and the measurement accuracy is very high.

The invention relates to a ferromagnetic resonance temperature measurement method based on a field sweeping method. The method comprises the following steps: applying a static magnetic field to a measured object containing ferromagnetic nanoparticles to saturate and magnetize the ferromagnetic nanoparticles; applying an alternating pulse excitation magnetic field along the vertical direction of the static magnetic field; determining the magnetic field intensity of the static magnetic field through a field sweeping method when the ferromagnetic nanoparticles generate ferromagnetic resonance; and calculating the temperature of the measured object according to the determined magnetic field intensity of the static magnetic field. According to the method provided by the invention, temperature measurement is carried out through the established relation model of the magnetic field intensity of the external static magnetic field and the temperature, the model is simple in form, the measurement method is simple and convenient, the internal temperature of the measured object can be rapidly and simply measured, and the measurement accuracy is very high.

The invention discloses a magnetic photonic crystal microsphere for enriching and separating aflatoxin B1 as well as a preparation method and application of the magnetic photonic crystal microsphere. The microsphere is a core-shell type surface molecular imprinting magnetic inverse opal photonic crystal microsphere, wherein the core is a photonic crystal microsphere which is of a magnetic inverse opal structure and is formed by silicon dioxide nanoparticles, polystyrene nanoparticles and ferroferric oxide magnetic nanoparticles through self-assembly and high-temperature firing, and the shell is a molecular imprinting layer which is modified through a molecular imprinting technology and can specifically recognize aflatoxin B1. The prepared core-shell type surface molecular imprinting magnetic inverse opal photonic crystal microsphere can selectively extract aflatoxin B1 in a sample, and compared with a biological antibody modified material, the stability of the material can be greatly improved, and the preparation cost of the material is reduced.

The present invention relates to a water-soluble polymer complex that includes a water-soluble block copolymer and a magnetic nanoparticle, wherein the water-soluble polymer complex has a nonzero net magnetic moment in the absence of an applied magnetic field at ambient temperatures. The water-soluble block copolymer is preferably a diblock or triblock copolymer and the magnetic nanoparticle is preferably a ferrimagnetic or ferromagnetic nanoparticle. The water-soluble complexes may be derivatized with reactive groups and conjugated to biomolecules. Exemplary water-soluble polymer complexes covered under the scope of the invention include PEG112-b-PAA40 modified CoFe2O4; NH2-PEG112-b-PAA40 modified CoFe2O4; PNIPAM68-b-PAA28 modified CoFe2O4; and mPEG-b-PCL-b-PAA modified CoFe2O4.

The invention discloses a magnetic compound-cyanide decomposing enzyme composite nanoparticle, its preparation method and application, and a method for treating electroplating wastewater by using it. The raw materials for making the composite nanoparticle include: spinel ferromagnetic nanoparticle, magnetic oxide Nanoparticles, SiO 2 Nanoparticles, cyanide decomposing enzyme, first polymer compound, second polymer compound, silane, amine compound, nucleoside monophosphate disodium salt, first inorganic metal salt, second inorganic metal salt; The stone ferromagnet is modified by amino groups, by wrapping SiO 2 The magnetic oxide nanoparticles are modified by epoxy groups, and then the metal adsorption coupling is carried out through the first inorganic metal and the enzyme, which increases the way and amount of enzyme coupling, and stabilizes the enzyme activity and applicable pH range and temperature range. At the same time, the magnetic substance can be used to absorb heavy metal ions or dyes and achieve the effect of decomposing cyanide, reducing the amount of flocculant used and the amount of sludge after treatment.

The invention discloses a method for preparing starch raw material carbon-coated nickel-zinc-ferromagnetic nanoparticles. 3.9H2O as raw material, Ni0.6Zn0.4Fe2O4 magnetic nanoparticles were prepared by self-propagating combustion method, Ni0.6Zn0.4Fe2O4 magnetic nanoparticles were coated with starch in situ, and then high-temperature hydrogen reduced starch to coat nickel-zinc ferrite. A carbon-coated nickel-zinc ferromagnetic nanomaterial is obtained. The magnetic nanomaterial has high saturation magnetization, low coercive force and residual magnetization, and is suitable for further modification to prepare magnetic resonance imaging contrast agents, biological analysis and drug carriers, hyperthermia media, catalysts, magnetic recording and magnetic fields. Materials such as separation media have important scientific significance and good application value.

The invention belongs to the field of nanometer materials, and specifically discloses a magnetic composite nanometer material, a preparation method and an application thereof. The raw materials for the preparation of the magnetic composite nanomaterial include Fe 3 o 4 Ferromagnetic nanoparticles, cellulose acetate and glyceryl trioleate, by modifying the surface of magnetic nanoparticles of cellulose acetate, and fixing glyceryl trioleate in the microporous structure of cellulose acetate; by controlling the ratio of solvent addition and temperature and other conditions, magnetic composite nanoparticles can be prepared. The preparation method of the magnetic composite nanomaterial is a chemical co-precipitation synthesis technology, which has the advantages of simple preparation process and equipment requirements, high stability of the produced material, and the obtained magnetic composite nanoparticle not only has a large specific surface area, but also has the advantages of being resistant to pollutants. The adsorption efficiency is fast, and it can be used for the adsorption of organic matter in sewage treatment; and there is less superparamagnetic interference to the material itself, and it can be quickly recovered under an external magnetic field, avoiding environmental pollution.

The invention discloses a ferromagnetic nano alpha-Fe2O3 with iron defects, and a preparation method thereof. According to the ferromagnetic nano alpha-Fe2O3 with iron defects, the molar ratio of Fe atom to O atom is controlled to be smaller than 1:1.5.

The invention discloses a low-temperature and low-pressure gas-phase preparation method of ferromagnetic chromium oxide nanoparticle film, which uses metal Cr as a precursor, through plasma gas-phase aggregation and real-time oxidation method, and utilizes the unique nucleation in the gas-phase aggregation process Growth and reaction environment, forming Cr oxide nanoparticles in the gas phase environment, and through the differential vacuum system, the formed nanoparticles are deposited on the substrate under high vacuum, forming a chromium oxide nanoparticle film at room temperature and low pressure, oxidation The main component of the material is chromium dioxide with ferromagnetism. The preparation method of the invention can be applied to the preparation process of high-density storage devices and nano-magnetic electronic devices, and has the characteristics of simple process, stability, high efficiency, easy scale and the like.

The invention discloses a polylactic acid shell of an electric energy metering box and a preparation method of the polylactic acid shell. The preparation method comprises the following steps: mixing the phase change material, the high-molecular surfactant and an alcohol-water mixed solution in a reaction container; starting a temperature control system to heat the reaction system to 30-100 DEG C under the condition of inert gas protective atmosphere; after the temperature of the reaction system is stable, adding a styrene monomer and an initiator, mixing and stirring at the stirring speed of 200-400r / min; when the reaction is carried out for 11-13 hours, ferromagnetic nanoparticles modified by a high-molecular surfactant are added, and the reaction is continued for 2-4 hours to obtain a phase change microcapsule; the preparation method comprises the following steps: putting polylactic acid into a dryer, and carrying out drying treatment at 55-65 DEG C for 22-26 hours to remove moisture; premixing polylactic acid and the phase change microcapsules, and performing melt extrusion and granulation through a double-screw extruder; and carrying out injection molding on the blended particles through an injection molding machine. Development of electrical branches can be effectively inhibited, the electrical aging process of the material is delayed, the service life of the material is prolonged, and the use safety is improved.

The invention provides a magnetofluid enhanced electromagnetic heating device and method for preventing and treating secondary hydrate around a well. At present, in the process of exploiting natural gas hydrates through a depressurization method, secondary hydrates or ice can be formed due to the fact that the temperature around a well is too low, a gas migration channel in sediment is blocked, and the gas production rate is affected. According to the device or method, a coil is arranged outside a shaft sleeve, and the coil generates a specific-frequency electromagnetic field radiated to stratum sediments. Under the action of the electromagnetic field, magnetite nano-particles naturally contained in the stratum sediment generate oscillating motion, and the aim of heating the stratum around the well is achieved due to heat generated by friction. In addition, in the hydraulic fracturing or slotting stage of the reservoir, the magnetofluid containing the ferromagnetic nanoparticles can be injected along with fracturing fluid, so that the magnetothermal effect of sediments is increased, and the heating effect is further enhanced. In this way, secondary hydrate or ice can be prevented from being formed around the well, pore channels in the sediment are kept unblocked, and therefore the exploitation efficiency of the natural gas hydrate is improved.

The invention relates to a preparation method of ferromagnetic nanoparticles grafted on surface of polyglycerol. Ferric oxalate pentahydrate is taken as a precursor compound, triethylene glycol is taken as a solvent, glycidol is taken as a surface modifier, the synthesis is performed through a one-pot process, and the method comprises the following steps: mixing an iron salt oxalate and the strongly polar high-boiling point solvent with a hydroxyl group, firstly reacting at the temperature of 200 DEG C for 1-10 hours, then reacting at the temperature of 280-350 DEG C for 1-10 hours, and naturally cooling to 25 DEG C-120 DEG C after the completion of the reaction; and then adding glycidol monomers, uniformly mixing, reacting at the temperature of 50-200 DEG C for 1-24 hours, then adding the polar organic solvent, precipitating, and separating obtained solids to get the ferromagnetic nanoparticles grafted on the surface of the polyglycerol. The preparation method disclosed by the invention has the advantages that compared with the two-step preparation of the ferromagnetic nanoparticles, the one-pot process preparation process is simple and easy to realize the large-scale industrial production; and the particle size of the ferromagnetic nanoparticles prepared by the method is 10-20nm, and the particle size distribution is uniform.