316 results about "Ferromagnetic particle" patented technology

The present invention discloses a grinding-polishing method based on magnetorheological effect. Said method is characterized by that in the magnetorheological fluid a kind of free abrasive material is added, used as grinding-polishing liquor and injected into the between of magnetic body and workpiece surface, under the action of magnetic field the ferromagnetic particles in the magnetorheological fluid can be arranged by strings to cover the abrasive material pacticles and can be constrained in the end face of magnetic body to form magnetic grinding brush, said magnetic grinding brush can be used for grinding-polishing workpiece surface. Said invention also provides a grinding-polishing device for implementing said grinding-polishing method. Said device includes grinding tool mounted on main shaft connected with motor and working table for mounting workpiece.

A catheter adapted to deliver therapeutic or diagnostic agents to a target tissue of a human body is disclosed. A catheter in accordance with the present invention comprises a magnetic field source for directing the flow of the therapeutic of diagnostic agent. The therapeutic or diagnostic agent may be conjugated with diamagnetic particles, ferromagnetic particles, super paramagnetic particles, or paramagnetic particles.

A pole piece for a permanent magnet MRI system and a method for increasing the stability of a gradient field in an MRI system. The method includes: obtaining an MRI system comprising a magnet capable of providing a gradient magnetic field within an image volume in an air gap; and fixing a plurality of pole pieces within said MRI system, thereby defining the air gap, the raw material of construction of the pole piece being a material including a plurality of ferromagnetic particles coated with an electrically insulating substance. The fixing increases the stability of said gradient field by at least 10% relative to that of a gradient magnetic field in an MRI system identical except for the use of the material in the fabrication of the pole pieces.

A magnetic lock device includes a first element and a second element that are capable of being detachably coupled together by attracting each other magnetically under the magnetic interaction of permanent magnets, wherein each of the first and second elements includes an annular permanent magnet having a center bore through it, a ferromagnetic disk-like plate disposed to make contact with the permanent magnet, and a ferromagnetic projecting member extending from the disk-like plate and through the center bore of the permanent magnet. All of the component parts for the first and second elements are covered with any suitable synthetic resin film, sheet or the like and shielded from the outside, so that any foreign matter such as dust, particularly ferromagnetic particles like iron, cannot enter the gap or space that is present between the outer peripheral wall of the projecting member and the inner peripheral wall of the center bore through the annular permanent magnet. In one specific form of the magnetic lock device, each of the first and second elements is entirely covered with any suitable non-magnetic, synthetic resin film, sheet, covering or casing, or is entirely covered with a coating of any suitable non-magnetic, synthetic resin layer. In another specific form, each of the first and second elements is covered with any suitable non-magnetic, synthetic resin film, sheet, covering or casing, or is covered with a coating of any suitable non-magnetic, synthetic resin layer, except for the ends of the ferromagnetic projecting members in the first and second elements engaging each other that remain uncovered or exposed. In both forms, each of the first and second elements includes an annular permanent magnet, wherein one annular permanent magnet has a given polarity (S or N) opposed to the polarity (N or S) of the other annular permanent magnet on the side on which the first and second elements are to engage each other.

A magnetorheological fluid-based device and method may include the use of magnetorheological (MR) fluid, a primary magnetic field to control the viscosity of the fluid, and a secondary magnetic field to reduce clumping of ferromagnetic particles.

The invention provides a composition (3) comprising: (i) a ferrofluid comprising a colloidal suspension (4) of ferromagnetic particles in a non-magnetic carrier liquid, and (ii) a plurality of electrically-conductive particles (5) having substantially uniform sizes and shapes, dispersed in the ferrofluid. Various types of substantially non-magnetic electrically-conductive particles (5) are described. Application of a substantially uniform magnetic field by magnet means (8) to the composition (3) causes the electrically-conductive particles (5) to form a regular pattern (9). The composition is used for providing anisotropic conductive pathways (9a, 9b) between two sets of conductors (2a, 2b; 7a, 7b) in the electronics industry. The composition may be a curable adhesive composition which bonds the conductors. Alternatively or in addition the electrically-conductive particles may have a latent adhesive property e.g. the particles may be solder particles. The ferrofluid may be a colloidal suspension of ferromagnetic particles in a liquid monomer.

A coated ferromagnetic particle comprises a ferromagnetic core and a coating. The coating comprises a residue resulting from a thermal treatment of a coating material comprising a polymer selected from the group consisting of polyorganosiloxanes, polyorganosilanes, and mixtures thereof. A composite magnetic article comprises a compacted and annealed article of a desired shape. The composite magnetic article comprises a plurality of coated ferromagnetic articles. Each coated ferromagnetic particle comprises a ferromagnetic core and a coating. The coating comprises a residue resulting from a thermal treatment of a coating material comprising a polymer selected from the group consisting of polyorganosiloxanes, polyorganosilanes, and mixtures thereof.

The invention provides a self-pressurized high-speed polishing method for the inner surface of a hole by means of abrasive particles and a magnetic flow. According to the method, the abrasive particles are coated with and restrained on the inner surface of the hole of a workpiece by the aid of ferromagnetic particles in a magnetorheological polishing fluid, which flows at a high speed, under the effect of a magnetic field produced by moving magnetic bodies, a flexible polishing abrasive brush flowing at a high speed is formed and reciprocates to rub against the inner surface of the hole of the machined workpiece to remove burrs and reduce the roughness of the inner surface of the hole, and burr removal and deterministic polishing are realized for various types of inner surfaces of holes. The invention further provides a self-pressurized high-speed polishing device for the inner surface of the hole by means of the abrasive particles and the magnetic flow. The device comprises a polishing mechanism, the magnetic bodies, a clamping mechanism, a sliding guide rail and a driving motor, wherein the driving motor drives the magnetic bodies to enable the polishing fluid to reciprocate in the hole at the high speed for polishing. The method and the device can solve problems that special holes are difficult to polish and the polishing efficiency is low, and have the advantages of high precision, high machining efficiency, low damage and low cost.

The invention relates to a nano particle taking Fe3O4 as core, in particular to a TiO2 / SiO2 / Fe3O4 nano particle with nuclear structure and manufacturing method thereof. The invention solves the technical problems that nano TiO2 particle catalyst has low catalytic efficiency under natural light and is difficult to meet recovery control while remaining high catalyst activity in sewage treatment. The method includes steps of preparing SiO2 / Fe3O4 solution, preparing titanium sol and mixing the prepared SiO2 / Fe3O4 solution and the titanium sol. The invention adopts ferromagnetic particle as a carrier core and prepared TiO2 / SiO2 / Fe3O4 particle with nuclear shell structure as catalyst, and the catalyst particle has good dispersity and water-solubility and can be fully contacted with organic pollutant in sewage, thereby not only having high efficiency of suspended phase photocatalyst but also realizing magnetic control of catalyst by super paramagnetic nuclear energy, thus being effectively recovered.

Provided is a particulate magnetic recording medium having good processing properties and being inexpensive to produce, similar to prior recording media, wherein by controlling the magnetic clusters that appear due to recording at short wavelengths and thinning of the magnetic layer, good high-density characteristics are achieved in combination with MR heads. The magnetic recording medium comprising an essentially nonmagnetic lower layer and a magnetic layer comprising a ferromagnetic powder and a binder in this order, wherein the magnetic layer has a thickness ranging from 0.01 to 0.15 mum and a coercivity equal to or higher than 159 kA / m, ferromagnetic particles contained in the ferromagnetic powder have a size less than ½ of the minimum recording wavelength, and an average size of magnetic cluster at DC erase is equal to or higher than 0.5x104 nm2 and less than 5.5x104 nm2.

A biosensor utilizing bio-functionalized magnetic nanoparticles is provided. An external magnetic field is applied to a suspension of magnetic nanoparticles. A linearly polarized incident light is applied to the suspension of magnetic nanoparticles. A photocurrent from polarized light scattering by bio-functionalized magnetic nanoparticles in liquid is detected. The magneto-optic sensing technique is applied to a micro-fluidic channel for rapid and sensitive detection with a small sample amount, and subsequent magnetic separation for detoxification. This technique is used for the detection of Brownian relaxation with time sweep as well as frequency sweep. The magneto-optical sensor enables rapidly detecting changes in local dynamic properties of the magnetic nanoparticles in liquids and magnetic modulation of ferromagnetic particles in liquid provides increased signal sensitivity.

A coated ferromagnetic particle comprises a ferromagnetic core and a coating. The coating comprises a residue resulting from a thermal treatment of a coating material comprising a polymer selected from the group consisting of polyorganosiloxanes, polyorganosilanes, and mixtures thereof. A composite magnetic article comprises a compacted and annealed article of a desired shape. The composite magnetic article comprises a plurality of coated ferromagnetic articles. Each coated ferromagnetic particle comprises a ferromagnetic core and a coating. The coating comprises a residue resulting from a thermal treatment of a coating material comprising a polymer selected from the group consisting of polyorganosiloxanes, polyorganosilanes, and mixtures thereof.

The present invention provides new polymer induction bonding technology. Induction heating technologies are utilized to weld, forge, bond or set polymer materials. The invention provides controlled-temperature induction heating of polymeric materials by mixing ferromagnetic particles in the polymer to be heated. Temperature control is obtained by selecting ferromagnetic particles with a specific Curie temperature. The ferromagnetic particles will heat up in an induction field, through hysteresis losses, until they reach their Curie temperature. At that point, heat generation through hysteresis loss ceases. This invention is applicable to bonding thermoplastic materials, wherein only the area to be heated has ferromagnetic particles in it; bonding of thermoset composites, which have been processed with a layer of thermoplastic material on one side; curing of thermoset adhesives or composite resins; or consolidating thermoplastic composites.

A membrane strip biosensor device (10, 20, 100) using a fluid mobile conductive composition of ferromagnetic particles bound to a conductive polymer bound to a capture reagent is described. The biosensor device is designed to detect analytes at low concentrations in near real-time with an electronic data collection system and can be small. The device can be used to detect pathogens, proteins, and other biological materials of interest in food, water, and environmental samples. The device can also be used for on-site diagnosis and against potential bioterrorism. Potential users include food processing plants, meat packaging facilities, fruit and vegetable packers, restaurants, food and water safety inspectors, food wholesalers and retailers, farms, homes, medical profession, import border crossing personnel, and the police force, military, space habitation and national security.

A biosensor utilizing bio-functionalized magnetic nanoparticles is provided. An external magnetic field is applied to a suspension of magnetic nanoparticles. A linearly polarized incident light is applied to the suspension of magnetic nanoparticles. A photocurrent from polarized light scattering by bio-functionalized magnetic nanoparticles in liquid is detected. The magneto-optic sensing technique is applied to a micro-fluidic channel for rapid and sensitive detection with a small sample amount, and subsequent magnetic separation for detoxification. This technique is used for the detection of Brownian relaxation with time sweep as well as frequency sweep. The magneto-optical sensor enables rapidly detecting changes in local dynamic properties of the magnetic nanoparticles in liquids and magnetic modulation of ferromagnetic particles in liquid provides increased signal sensitivity.

Electrodynamic apparatus such as a motor, generator or alternator is configured having a stator core assembly formed of pressure shaped processed ferromagnetic particles which are pressure molded in the form of stator modules. These generally identical stator modules are paired with or without intermediate modules to provide the stator core structure for receiving field winding components. In one embodiment, two sets of the paired stator modules are combined in tandem to enhance operational functions without substantial diametric increases in the overall apparatus.

The present invention relates to ferromagnetic particles capable of exhibiting a high purity and excellent magnetic properties from the industrial viewpoints and a process for producing the ferromagnetic particles, and also provides an anisotropic magnet, a bonded magnet and a compacted magnet which are obtained by using the ferromagnetic particles. The ferromagnetic particles comprising an Fe16N2 compound phase in an amount of not less than 80% as measured by Mössbauer spectrum and each having an outer shell in which FeO is present in the form of a film having a thickness of not more than 5 nm according to the present invention can be produced by subjecting iron oxide or iron oxyhydroxide having an average major axis diameter of 40 to 5000 nm and an aspect ratio (major axis diameter / minor axis diameter) of 1 to 200 as a starting material to dispersing treatment to prepare aggregated particles; subjecting the iron compound particles passed through a mesh to hydrogen reducing treatment at a temperature of 160 to 420° C.; and then subjecting the resulting particles to nitridation treatment at a temperature of 130 to 170° C.

The invention relates to a preparation method for tape casting of a gradient material in a revolving magnetic field. The existing method has complicated process and high requirement on equipment. The method comprises the following steps: mixing ferromagnetic particles and non-magnetic particles into mixed powder; adding an organic solvent, a dispersing agent, a plasticizing agent and a cementing agent into the mixed powder; adding the plasticizing agent and the cementing agent into the mixed powder after ball milling; and obtaining dispersed slurry through ball milling, ultrasonic dispersion treatment and vacuum degassing; pouring the dispersed slurry into a casting machine to apply revolving magnetic field on the substrate which is made of high temperature resistant ceramic; and carrying out dry combustion to obtain a finished product. The method can prepare thin and flat gradient material with large area in a large ingredient range, and the mature tape casting process is used to ensure that the process for producing the gradient functional material is simplified and cost is reduced.

Electrodynamic apparatus such as a motor, generator or alternator is configured having a stator core assembly formed of pressure shaped processed ferromagnetic particles which are pressure molded in the form of stator modules. These generally identical stator modules are paired with or without intermediate modules to provide the stator core structure for receiving field winding components. In one embodiment, two sets of the paired stator modules are combined in tandem to enhance operational functions without substantial diametric increases in the overall apparatus.

The invention discloses an online particle detection device and method based on a microfluidic chip. The online particle detection device comprises the microfluidic chip, a first impedance analyzer and a second impedance analyzer, wherein the microfluidic chip comprises a substrate part and a main chip body arranged on the substrate part; the main chip body comprises a first liquid inlet, a second liquid inlet, a first liquid outlet and a second liquid outlet formed in the substrate part, a particle separation region for separating ferromagnetic particles from non-ferromagnetic particles in oil liquid under the action of a magnetic field, a magnetic part placement region arranged on the substrate plate and located on one side of a first microchannel, a magnetic part placed on the magnetic part placement region and used for providing the magnetic field, and a particle detection region. The online particle detection device and method provided by the invention can realize the distinguishing and the online continuous counting of the ferromagnetic particles and the non-ferromagnetic particles in the oil liquid, and is suitable for online detection and analysis of oil liquid, in particular the detection and analysis of oil liquid on sailing ships.

The invention relates to magneto-rheological fluid with good settling agglomeration resistance. The magneto-rheological fluid comprises the following ingredients in parts by weight according to 100 volume parts: 125-225 parts of ferromagnetic particles, 30-85 parts of carrier fluid, 0.2-5 parts of xanthan gum, and 0-12.5 parts of additives, wherein the additives are a thixotropic agent, a dispersing agent, an antioxidant and a lubricant when the carrier fluid is water-based; and when the carrier fluid is oil-based, the additives are a thixotropic agent, a dispersing agent, and a lubricant. The magneto-rheological fluid is good in stability within a larger temperature range (minus 18 DEG C-130 DEG C), difficult to settle, and also keeps the original performances, namely high shearing stress and good friction property.

A magnetic recording medium having on a flexible, nonmagnetic support, in order, a lower layer comprising a nonmagnetic powder and a binder, and a magnetic layer comprising a ferromagnetic powder and a binder. The average thickness d of the magnetic layer is 0.02-0.2 mum. The ferromagnetic powder contained in the magnetic layer is a platelike hexagonal ferrite magnetic powder with a mean plate diameter of not more than 40 nm. The nonmagnetic powder contained in the lower layer is an acicular inorganic powder with a mean main axis length of not more than 0.2 mum. Further, the plate ratio of the ferromagnetic powder is not greater than the acicular ratio of the lower layer inorganic powder. A particulate magnetic recording material exhibiting a high C / N in high-density magnetic recording, particularly in reproduction with MR heads is provided.

Various magnetically eyelash attaching prosthetic systems of the present disclosure are provided, comprising: (a) a load-bearing magnetic eyeliner adherable to an eyelid surface and incorporating magnetic particles compatible with a load-bearing structural adhesive; and (b) a magnetic eyelash prosthetic incorporating one or more magnetic elements exhibiting high magnetic coercivity and positioned at least at the base of the eyelash prosthetic, enabling the interaction between the ferromagnetic particles (incorporated into the load-bearing eyeliner) and the ferromagnetic elements (incorporated into the magnetic eyelash prosthetic) to stably attach the eyelash prosthetic to a pre-coated eyelid surface. Various methods for producing and using the various magnetically attachable eyelash prosthetics and the various load-bearing magnetic eyeliners are also provided.

The invention relates to a method for preparing a gel injection mold of a gradient material in a revolving magnetic field. The existing method is difficult to realize continuous and even variation of material compositions, or difficult to obtain large-thickness materials and the like. The method comprises the following steps: mixing ferromagnetic particles and non-magnetic particles into mixed powder; preparing organic monomer and a cross-linking agent into premixed solution; adding the mixed powder into the premixed solution; adding a dispersing agent into the solution; obtaining a dispersedslurry through ball milling and ultrasonic dispersion treatment; adding an initiator and a catalyst into the dispersed size; pouring the size into a mold after stirring; applying the revolving magnetic field outside the mold; and taking out the mold after gelling, drying, pressing and sintering. The method can prepare gradient materials with various thicknesses in a large ingredient range, has continuous variable and controllable ingredients, simplified process and reduced cost.

A magnetic recording medium comprising a nonmagnetic substrate, and a soft magnetic layer and a ferromagnetic layer formed in this order on the nonmagnetic layer, in which the ferromagnetic layer has a thickness of from 3 to 150 nm, contains spherical, ellipsoidal or plate-form ferromagnetic particles and a binder, and has an axis of easy magnetization substantially in the vertical direction, and the soft magnetic layer contains spherical or ellipsoidal Fe—Co-containing soft magnetic particles having a saturation magnetization of from 170 to 220 Am2 / kg, and a binder.

The present invention relates to Fe16N2 particles in the form of a single phase which are obtained by subjecting iron oxide or iron oxyhydroxide whose surface may be coated with at least alumina or silica, if required, as a starting material, to reducing treatment and nitridation treatment, a process for producing the Fe16N2 particles in the form of a single phase for a heat treatment time of not more than 36 hr, and further relates to an anisotropic magnet or a bonded magnet which is obtained by magnetically orienting the Fe16N2 particles in the form of a single phase. The Fe16N2 particles according to the present invention can be produced in an industrial scale and have a large BHmax value.

The invention relates to the technical field of water treatment, in particular to a novel technology for recycling a fluorinated surfactant in water. The technology comprises the steps that firstly, ferromagnetic particles are synthesized or selected, then, the surface of a magnetic material is coated with an inert material layer, and then, the surface of the magnetic material is coated with a large number of reaction species; then, polyethylene glycol and fluorocarbon with the tail end capable of reacting with the reaction species is added, and polyoxyethylene chains and fluorocarbon chains are linked to the surfaces of the particles; the particles with the surfaces covered with the polyoxyethylene chains and fluorocarbon chains are dispersed into raw water containing a fluorinated surfactant; when adsorption is saturated, a high magnetic field is utilized for extracting the particles from water, and therefore the fluorinated surfactant in water can be removed, and the treated clean water can be directly discharged. The novel technology has the advantages that the method is simple and reliable, energy consumption is low, the magnetic particles can be recycled, and the novel technology can be used for recycling fluorinated surfactant in fluorine-containing polymer production and treating wastewater of the fluorinated surfactant.

An exemplary magnetic recording medium with a high recording density and a low medium noise is provided. The magnetic recording medium includes a non-magnetic substrate, a soft magnetic layer, an oxygen-containing intermediate layer, and a perpendicular magnetic recording layer, arranged in contact with one another, in that particular order. The perpendicular magnetic recording layer has a composite layer structure with ferromagnetic grains and a matrix of an amorphous carbon-containing structure. The amorphous carbon-containing structure is dispersed so as to essentially surround the individual ferromagnetic grains, within the perpendicular magnetic recording layer. Methods for making such magnetic recording media also are provided.