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.

Ferromagnetic nanoparticles which are produced by reducing, in the presence of a polymer, two or more metals having different reduction potentials twice or more, using two or more reducing agents having different reduction potentials, a material coated with a dispersion of ferromagnetic nanoparticles in which the ferromagnetic nanoparticles are dispersed, and a magnetic recording medium which has a magnetic layer consisting of the material. The ferromagnetic nanoparticles having a holding power Hc of 95.5 kA/m or more, the material coated with the dispersion of ferromagnetic nanoparticles having excellent industrial coatability, and the magnetic recording medium using the dispersion are provided.

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 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.