704results about "Magnetic liquids" patented technology

A coated assembly with an inductance of from about 0.1 to about 5 nanohenries and a capacitance of from about 0.1 to about 10 nanofarads. The coated assembly contains a stent and a coating. When the assembly is exposed to radio frequency electromagnetic radiation with a frequency of from 10 megahertz to about 200 megahertz, at least 90 percent of the electromagnetic radiation penetrates to the interior of the stent.

One embodiment of the invention includes an MR fluid of improved durability. The MR fluid is particularly useful in devices that subject the fluid to substantial centrifugal forces, such as large fan clutches. A particular embodiment includes a magnetorheological fluid including 10 to 14 wt % of a hydrocarbon-based liquid, 86 to 90 wt % of bimodal magnetizable particles, and 0.05 to 0.5 wt % fumed silica.

The invention relates to a method for preparing ethylenediamine modified chitosan composite magnetic microspheres and application thereof. The method specifically comprises the following steps of: mixing acidic aqueous solution of chitosan and a water-based magnetofluid first, then crosslinking by using glutaraldehyde, then adjusting the pH value to form a gelatinous precipitate, then modifying by using ethylenediamine and epichlorohydrin, and washing and drying to obtain a final product. The product has good absorption effect on radionuclide aranium and metal ions such as heavy metal Pb, Cr and the like; the removal rate reaches over 95 percent when the initial concentration of various ions is within the range of 200mg/L; and the product has quick absorption rate and good regeneration performance. The ethylenediamine modified chitosan composite magnetic microspheres can be used for metal recovery and pollution remediation in mines, radioactive waste water, smelteries, electronics factories and waste water of electroplating factories.

A method and apparatus for finishing a workpiece surface using MR fluid is provided wherein the workpiece is positioned near a carrier surface such that a converging gap is defined between a portion of the workpiece surface and the carrier surface; a magnetic field is applied substantially at said gap; a flow of stiffened MR fluid is introduced into said converging gap such that a work zone is created in the MR fluid to form a sub-aperture transient finishing tool for engaging and causing material removal at the portion of the workpiece surface; and the workpiece or the work zone is moved relative to the other to expose different portions of the workpiece surface to the work zone for predetermined time periods to selectively finish said portions of said workpiece surface to predetermined degrees.

A method of producing at least one of microscopic and submicroscopic particles includes providing a template that has a plurality of discrete surface portions, each discrete surface portion having a surface geometry selected to impart a desired geometrical property to a particle while being produced; depositing a constituent material of the at least one of microscopic and submicroscopic particles being produced onto the plurality of discrete surface portions of the template to form at least portions of the particles; separating the at least one of microscopic and submicroscopic particles comprising the constituent material from the template into a fluid material, the particles being separate from each other at respective discrete surface portions of the template; and processing the template for subsequent use in producing additional at least one of microscopic and submicroscopic particles. A multi-component composition includes a first material component in which particles can be dispersed, and a plurality of particles dispersed in the first material component. The plurality of particles is produced by methods according to embodiments of the current invention.

The invention relates to a magnetic rheological polishing fluid and a preparing method for the fluid. The magnetic rheological polishing fluid comprises by volume magnetic particles 30-40%, pure water 45-55%, additive 5-10%, surface active agent 3-5% and polishing powder 5-8%. The preparing method comprises: the magnetic particles are surface cleaned and activated, the surfaces of the magnetic particles are treated by a hi-speed ball pulverizer. The magnetic rheological polishing fluid prepared by the invention is of hydrolyzation function. The preparing method is simple. The fluid is of a good resistance to settlement and conglobation, low zero-field viscosity, high polishing efficiency, good effect, long service life, and is applicable for optic polishing. The invention solves such problems of prior magnetic rheological polishing fluid as high viscosity, weak magnetizing strength, liable to caking, not stable in settling and conglobation, liable to rust, short service life and low efficiency. The magnetic rheological polishing fluid prepared by the invention is of high efficiency, and can facilitate the surface finish of a k9 glass to increase from 400nm to 0.6 nm in 30 minutes. The invention can be widely used in the super surface polishing of optic glass.

The invention relates to a water-based magnetorheological polishing solution for optical manufacture, which is formed by the following volume components, water-based remixed carrier liquid 25%-75% and additive component 25%-75%, wherein the additive component is dispensed by the following volume percentage, carbonyl iron powder 80%-90%, nanometer iron powder 4%-10% and polishing powder 4%-10%, the water-based remixed carrier liquid which is measured according to volume percentage comprises deionized water 85%-90%, dispersing agent 3%-5%, wetting agent 2%-5% and thixotropic agent 3%-5%, the method for preparing comprises the following steps: mixing deionized water and thixotropic agent, stirring in indoor temperature for 1-2 hours, and adding dispersing agent, stirring in indoor temperature for 0.5-1 hour, and then adding wetting agent, stirring in indoor temperature for 0.5-1 hour, getting water-based remixed carrier liquid, mixing additive component and water-based remixed carrier liquid, adding into a ball-milling tank, adding into a steel ball according to mass ratio which is 1:10, grinding for 3-5 hours in the speed which is 20-30r/m, separating out a steel ball, and getting products. The polishing solution of the invention has the advantages of excellent stability, high rheological property, excellent oxidation resistance property and simple and environmental-friendly preparation technology.

Aqueous coating compositions containing acid stable metal dispersions, prepared by chemical reduction in aqueous medium, are obtained by using a N-quaternized cellulose derivative as binder. They can be used for the preparation of heat mode recording layers, magnetic layers and conductive layers.

The invention discloses a preparation method of a magnetic antiphase demulsifier. The preparation method is characterized by firstly, preparing monodisperse ferroferric oxide magnetic microspheres by a hydrothermal method; secondly, coating a layer of thin silicon dioxide on the surfaces of the monodisperse ferroferric oxide magnetic microspheres, synthesizing magnetic microspheres with nuclear shell structures, performing group functional modification on the nuclear shell magnetic microspheres by using a silane coupling agent KH560; at last, performing grafting reaction by using the activity of functional groups and an antiphase demulsifier to obtain the magnetic antiphase demulsifier; the magnetic antiphase demulsifier prepared by the preparation method can improve the efficiency of original antiphase demulsifiers and has the characteristics of easy separation, high oil removing rate, obvious separation effect to oil-containing sewage, little use amount and high efficiency.

The metal oxide particle dispersion for manufacturing a particulate magnetic recording medium contains metal oxide particles, solvent, and a polyester compound having one or more groups selected from the group consisting of a carboxyl group and a salt thereof, a phosphoric acid group and a salt thereof, a hydroxyl group and a nitrogen-substituted alkylene group, but substantially not containing ferromagnetic powder.

The invention relates to a magnetic rheologic liquid and its manufacture method. The magnetic rheologic liquid is stable suspension containing micronsized magnetic particle and carrier liquid and magnetic particle and high molecular compound re cross linked on surface, whose composition ratio according to weight percentage is magnetic particle 67-94%, high molecular compound 1-24% and carrier liquid 4-20%. Some supplements whose weight percentage is not larger than 5% can be added into carrier liquid, whose manufacture method is that, firstly produce magnetic particle or magnetic particle covered by silicon oxide and aluminium oxide, then make the magnetic particle to be that which has cross linked on surface with high molecular compound, finally mix and stir the mixture of magnetic particle, carrier liquid and added substance to be magnetic rheologic liquid according to suitable match. The invention has its stability of suspension, mechanical behavior of magnetic rheologic liquid and reversibility of solid-liquid phase transformation all reach the level of magnetic rheologic liquid imported and is suitable in the fields like aerospace, mechanical engineering, automobile industry, precision finishing, building engineering and medical and health.

The invention belongs to the technical field of the preparation of iron oxide magnetofluids and particularly relates to an aqueous reduction based synthesis method of superparamagnetic ferroferric oxide nanoparticles. According to the aqueous reduction based synthesis method, an inorganic metal water-soluble compound (ferric salt) serves as an iron source, a reducing compound and a stabilizer which can be coordinated with iron serve as raw materials, and reduction reaction is carried out in an aqueous solution to generate the ferroferric oxide magnetofluid in situ. The aqueous reduction based synthesis method provided by the invention has the advantages of mild reaction condition and good repeatability, is easy to operate and safe, and the ferroferric oxide nanoparticles prepared by adopting the aqueous reduction based synthesis method overcome the defects that the ferroferric oxide particles prepared by adopting the traditional aqueous co-precipitation method are easy to agglomerate, can not be dispersed uniformly and are affected in application. The ferroferric oxide nanoparticles with stable performance are prepared successfully by adopting the aqueous reduction based synthesis method, and the ferroferric oxide nanoparticles have good biocompatibility, can form the magnetofluid in an aqueous solution and can be widely applied to the biomedical fields of magnetic resonance imaging, magnetofluid thermotherapy, cell separation, protein separation, DNA purification, immunodetection, magnetically targeted medicine carriers.

A soft magnetic metal powder having a predetermined particle size (about 1 μm) or less is kneaded with plastic or rubber in a volume ratio of about 10% to 50%, and preferably, in a content of 10% to 40%, and the kneaded composite is subjected to working which extends a composite material in one direction, such as extruding, rolling, rolling after extruding, drawing after extruding, or rolling after injection. As a result, the magnetic permeability can be enhanced, the direction dependency can be given to magnetic permeability, the dimensional accuracy can be improved, and the magnetic core material can be made hard to be damaged.

Magnetic particles capable of binding a target substance, which comprise a magnetic material and a matrix material, wherein the magnetic material is remanent upon exposure to a magnetic field and the matrix material has a surface comprising functional groups which promote disaggregation of the particles in the presence of a liquid phase.

This invention relates to water base Fe3O4 magnetic liquid process and provides one water base magnetizing liquid and its process method. This invention adopts shell chitose ramification of CM-sephadex-C25 as surface activity agent to synthesize the Fe3O4 water base magnetizing liquid.

Methods and apparatus for fluid conditioning to reduce scaling, inactivate microbes, reduce surface tension, maintain fluid composition, and improve pumping are provided for use in treating crude petroleum, industrial water, agricultural water, municipal water supplies, or any fluid flow system and comprise electromagnets of variable control that can be powered or in which a current can be induced by a permanent magnet. Magnetic field direction and intensity can be selected depending on the nature of the fluid and in some embodiments, the field can be varied during operation, including pulsing and variably selecting one or more field directions and intensities, or combinations thereof, during operation. A non-magnetic fluid transfer conduit section has at least one conductor assembly mounted about the section. In one embodiment, the conductor assembly comprises a concentric, tilted double helix coil or multipole coil. If desired, one or more rotating or reciprocating permanent magnets may be located in magnetic field contact with one or more multipole conductor assemblies and rotated or reciprocated to induce a current in the multipole conductor assembly, thereby to induce a magnetic field in the conductor assembly.

The invention discloses a magnetorheological fluid multi-stage treatment device and a control method and component manufacturing method thereof and belongs to the technical field of machine manufacturing. The magnetorheological fluid multi-stage treatment device comprises a preposition piston cylinder, a middle piston cylinder, a postposition piston cylinder, a preposition piston, a middle piston, a postposition piston, a preposition filtering box, a middle filtering box, a postposition filtering box, a preposition filtering mesh, a middle filtering mesh and a postposition filtering mesh. The preposition piston cylinder is connected with the preposition piston through a bolt, the preposition bolt is matched with an inner cavity of the preposition filtering box, the preposition filtering box is vertically arranged, and the axis is in the vertical direction; meanwhile, the invention further provides corresponding control method and a key component manufacturing method of the device. According to the magnetorheological fluid multi-stage treatment device and the control method and component manufacturing method thereof, a two-standing three-filtering mode is adopted to filter mixed liquid, the characteristic of the mixed liquid at each stage is fully utilized, and the purpose of fast and thoroughly separating magnetic substances and solvent is finally achieved.

Magnetorheological devices, including damping devices, rotary devices, and haptic systems constructed with said devices are disclosed. The devices contain dry magnetically-responsive particles, or MR fluids containing the magnetically responsive particles. The magnetically soft particles characterized by a single process yield population of atomized particles having a cumulative 10%, 50% and 90% by volume, fraction within specified size, i.e., D₁₀ of from 2 up to and including a D₁₀ of 5 μm, a D₅₀ 8 μm up to and including a D₅₀ of 15 μm, a D₉₀ of 25 μm up to and including a D₉₀ of 40 μm, and characterized by a least squares regression of log normal particles size against cumulative volume % fraction of greater than or equal to 0.77.