CN1399783A - Magnetic fluid - Google Patents
Magnetic fluid Download PDFInfo
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- CN1399783A CN1399783A CN00816121A CN00816121A CN1399783A CN 1399783 A CN1399783 A CN 1399783A CN 00816121 A CN00816121 A CN 00816121A CN 00816121 A CN00816121 A CN 00816121A CN 1399783 A CN1399783 A CN 1399783A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/42—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of organic or organo-metallic materials, e.g. graphene
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/0036—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties showing low dimensional magnetism, i.e. spin rearrangements due to a restriction of dimensions, e.g. showing giant magnetoresistivity
- H01F1/0045—Zero dimensional, e.g. nanoparticles, soft nanoparticles for medical/biological use
- H01F1/0054—Coated nanoparticles, e.g. nanoparticles coated with organic surfactant
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/44—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of magnetic liquids, e.g. ferrofluids
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
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Abstract
There is disclosed a magnetic fluid medium which comprises a plurality of ferro- or ferri-magnetic particles, each of which particles has a largest dimension no greater than 100 nm, said particles having been prepared by a process which includes a step in which the particles are formed within an organic macromolecular shell.
Description
The present invention relates to a kind of magnetic fluid medium (flowing molten iron body), it comprises the nanometer iron that is dispersed in the carrying object or the suspension of ferrimagnetism particulate.The method for preparing the flowing molten iron body is also disclosed.
The flowing molten iron body is nanometer iron or the stable suspension of ferrimagnetism particulate in carrying object.Particulate is enough little so that heat energy can be kept stable dispersion.But, no matter up to the present use which kind of method to synthesize the flowing molten iron body, always (promptly the having wide relatively particle size scope) of this dispersion polydispersion character.
Term " ferromagnetism " is commonly used to refer to contain the material of " ferromagnetism " or " ferrimagnetism " in the prior art.Can utilize the present invention to prepare and contain iron or ferrimagnetism nanoparticle.
According to a first aspect of the invention, a kind of magnetic fluid medium that contains multiple iron or ferrimagnetism particulate is provided, the full-size of each particulate is no more than 100 nanometers, and described particulate prepares by following method: it is included in the step that forms described particulate in the organic macromolecule shell.
The full-size of preferred iron or ferrimagnetism particulate is no more than 50 nanometers, more preferably no more than 15 nanometers.
Preferred magnetic fluid medium is monodispersed, and we refer to this, and the maximum sized variation of particulate is no more than approximately 10% in the fluid, preferably is no more than 5%.
Usually, the shape of nanoparticle is spherical substantially, and in this case, full-size refers to the diameter of particulate.In some cases, can form other particulate form, in such cases, the size of particulate is meant the size that it is maximum.
By the method that particulate forms, originally each iron or the ferrimagnetism particulate that obtain are loaded in the organic macromolecule at least in part.In one embodiment, magnetic fluid medium of the present invention is included in and forms the particulate that still is stored in the organic macromolecule in the organic macromolecule.In this embodiment, the organic macromolecule shell can functionalised (seeing following description).In another embodiment, the shell of removable organic macromolecule and remaining nanoparticle itself, and also in another execution mode, the shell of organic macromolecule can be carbonized to provide and surround the carbon-coating that nanoparticle is examined.
The big molecule of term refers to the aggregate of molecule or molecule in the present invention, and molecular weight is more than 1500kD, typically less than 500kD.
Big molecule should have and holds or hold the ability of iron or ferrimagnetism particulate to small part, therefore comprises the suitable hole that can hold particulate; Such hole is encapsulated in the big molecule usually fully.As selection, big molecule can comprise the suitable through hole that is not surrounded fully, but only it has the ability of accepting and supporting magnetic particle; For example, by the defined through hole of the annular space in the big molecule.
Suitable organic macromolecule is to have the protein that holds suitable hole of nanoparticle or through hole to can be used for the present invention.The preferred apoferritin matter of the present invention (it is a kind of ferritin, and the hole is empty in ferritin).But other suitable protein comprises: for example, and flagellum L-P ring and virion shell.
Selected iron or ferrimagnetic material should be the materials with the orderly ability of magnetic.It can be metal, metal alloy or M-type or ferrospinel.Metal, metal alloy or ferrite can comprise following one or more: aluminium, barium, bismuth, cerium, chromium, cobalt, copper, dysprosium, erbium, europium, gadolinium, holmium, iron, lanthanum, lutetium, manganese, molybdenum, neodymium, nickel, niobium, palladium, platinum, praseodymium, promethium, samarium, strontium, terbium, thulium, titanium, vanadium, ytterbium and yttrium.Metal, metal alloy or ferrite preferably comprise following one or more: cobalt, iron and nickel.
In an execution mode of magnetic fluid medium of the present invention, particulate be loaded into or or be encapsulated in the organic macromolecule, the optimization protein mass shell, it can suppress to assemble and oxidation also can provide a kind of surface, and this surface can functionalised so that it can be dispersed in the multiple carrying object or be attached to pollutant.For example, can make functionalisation of surfaces have hydrophobicity, therefore allow to be dispersed in the nonpolar carrying object.Another example is to make functionalisation of surfaces with for example part of metal bonding, and medium is used for from removing the application of metal pollutant as waste material.
In this embodiment, selected iron or ferrimagnetic material preferable alloy are as cobalt, iron or nickel; Or metal alloy; Or M-type ferrite.More preferably iron or ferrimagnetic material are metal or metal alloy.
The present invention most preferably uses iron storage protein, ferritin, and its inner cavity is used for preparing nano magnetic particle.The molecular weight of ferritin is 400kD.In the iron metabolism of whole live species, ferritin to be utilized, and its structure can be kept to heavens therein.It is made up of the subunit of 24 self assemblies, and the hollow shell of about 12 nanometers of external diameter can be provided.It has the hole of diameter 8 nanometers, can store 4500 iron (III) atom that exists with the paramagnetic hydrated ferric oxide usually.But removable this hydrated ferric oxide ferritin of hydrated ferric oxide (lack be called " apoferritin ") and introduce other material.Subunit in ferritin fills closely; But the passage that leads to the hole is arranged at 3-weight or 4-solid axle direction.The big molecule that the present invention preferably uses be deferrization iron egg from matter, it has the hole of diameter 8 nanometer sizes.The diameter of iron in this protein or the ferrimagnetism particulate of will packing into is up to about 15 nanometers, yet protein can be upheld to hold the big particulate of diameter group 8 nanometers.
Ferritin is natural to be present in vertebrate, invertebrate, plant, fungi, saccharomycete and the bacterium.It also can be synthetic by recombinant technique.Such synthesized form can be identical with natural form, although might synthesize the form of variation, but still is retained in the principal character that can hold particulate in its inner cavity.The all natural and synthetic forms of expection ferritin all can be used in the present invention.
The carrying object of flowing molten iron body itself is known.Carrying object can be a polarity or nonpolar.Typical polarity carrying object comprises for example ethanol of water, lower alcohol, synthetic resin.Preferred water of the present invention.Spendable typical nonpolar carrying object is an organic solvent, for example heptane, dimethylbenzene or toluene, other hydro carbons, polyethylene glycols, polyphenyl ethers, perfluoropolyether, sila hydro carbons, halohydrocarbon or styrene.
Prepare nanoparticle by the following method: the common organic macromolecule suspension in water-bearing media wherein and comprises nanoparticle or is combined by suitable metal (one or more) ion source that nanoparticle is formed.As selection, but this is the inferior optimal way of the present invention, and metal ion source can be present in the suspension, to wherein adding the organic macromolecule source.
Organic macromolecule and metal ion mix the back and stir to guarantee its homogenizing.
If nanoparticle comprises metal element, preferably under inert atmosphere, on suspension, reduce, in the organic macromolecule hole, form the nano metal particulate thus.If nanoparticle is a ferrite, then in the organic macromolecule hole, form the ferrite nano particulate by carrying out oxidation.During adding metal ion (used ion can be identical or different in each repetition period) formation nanoparticle, the reducing/oxidizing step can repeat.
For example, handle the suspension obtain to remove the particulate that is not encased in the big molecule by osmotic technique.If necessary, separable installed nanoparticle is for example carried out centrifugation by form suspension in the carrying object medium of hope before.
In some embodiments, macromolecular shell can be removed and the remaining nanoparticle that does not have shell.For example, be protein as shell, can make it change character by for example changing change pH values, thereby like this by for example dialysis or the centrifugal protein material of removing modification.
In other execution mode, shell can be carbonized so that the carbon shell to be provided to particulate.Most preferably, in suspension, finish said process by the laser pyrolysis.But another kind of separating particles also makes the method for protein coat carbonization be, for example again before the suspended particulates, finishes by the heating in the stove in the carrying object of hope.
In a preferred embodiment of the present invention, organic macromolecule is an apoferritin.Method below in this preferred implementation, using.
Described method is at first removed hydrated ferric oxide nuclear from the native ferritin aqueous solution, sodium borohydride reduction by for example aqueous metal salt, the orderly metal particle of iron or ferrimagnetism can be introduced in the hole of ferritin, separate the distribution of sizes that obtains close limit by ultracentrifugation or magnetic subsequently, and the dispersion of particulate in carrying object.
Metal alloy is endorsed by the sodium borohydride selective reduction of water-soluble metal salt and is generated in apoferritin protein.Other method of reducing comprises: carbon, carbon monoxide, hydrogen, hydrazine hydrate or electrochemistry.Similarly reaction can be used to generate the rare earth/transition metal alloy.As selection, oxidable suitable solution is to obtain M-type or ferrospinel nuclear.Oxidation can be chemistry or electrochemical, and purpose is to generate the metallic iron oxysome.
In more detail, use iron protein sealing iron or ferrimagnetism particulate, its full-size is limited (however, but its have crooking ability thereby can hold diameter greatly to the particulate of about 15 nanometers) by the maximum inner diameter of ferritin 8 nanometers.Thereby at first obtain apoferritin and prepare particulate by removing hydrated ferric oxide nuclear.It also can be finished by in nitrogen current the sodium acetate solution that has cushioned being carried out dialysis.For example use TGA to reduce chelation and can remove hydrated ferric oxide nuclear.Subsequently sodium chloride solution is repeated dialysis to remove as-reduced hydrated ferric oxide nuclear fully from solution.
In case the generation apoferritin will be introduced magnetic particle with following method.Reducing metal salting liquid in the presence of apoferritin at first.Described operating in carried out in the inert atmosphere with protection metal particle not oxidized (the oxidation meeting reduces their magnetic property).The composition of metal salt solution also can be reduced and generate alloy or precursor material.The composition of the oxidable iron of another method (II) salt and other slaine.Obtained not being subjected to the metallic iron oxysome particulate of negative oxidation like this.Available slaine comprises the salt of following metal: aluminium, barium, bismuth, cerium, chromium, cobalt, copper, dysprosium, erbium, europium, gadolinium, holmium, iron, lanthanum, lutetium, manganese, molybdenum, neodymium, nickel, niobium, palladium, platinum, praseodymium, promethium, samarium, strontium, terbium, thulium, titanium, vanadium, ytterbium and yttrium.
Although detailed preparation method has used natural horse spleen ferritin, the present invention should not regard as and is limited to described source.Ferritin is present in vertebrate, invertebrate, plant, fungi, saccharomycete, the bacterium or even is obtained by recombinant technique.
After obtaining iron or ferrimagnetism particulate, moisture suspension can directly be used as magnetic fluid medium (flowing molten iron body).But use other carrying object by extraction or passivation particulate.Described passivation or extraction can be finished by the following method: be coated with in surfactant and wrap up in protein, or make it to form derivative with organic chain.But the present invention should not regard described these methods that are limited to as.The carrying object of other use is an organic solvent: for example heptane, dimethylbenzene or toluene, hydro carbons, synthetic resin, polyethylene glycols, polyphenyl ethers, perfluoropolyether, sila hydro carbons, halohydrocarbon or styrene.Prepare method existing description in U.S. Patent No. 6068785 of flowing molten iron body, its content is hereby incorporated by.Many books and list of references have also been discussed the magnetic fluid science, comprise their preparation.These lists of references comprise: magnetic fluid application manual, B.Berkovsky chief editor, Begell publishing company, New York (1996); The flowing molten iron body dynamics, R.E.Rosensweig, Cambridge University Press, New York (1985); The orderly material Performance Manual of ferrimagnet-magnetic, E.P.Wohlfarth edits, the 8th chapter, North-Holland publishing company, New York, and " the 7th international magnetic fluid proceeding ", magnetics and magnetic material magazine, the 149th volume, the 1st～2 phase (1995).
In the present invention, using ferrite is that it can be used to select uniform particulate by the advantage that encapsulation methods prepares magnetic particle.Narrow distribution of sizes can improve the monodispersity of fluid, and makes it have the more dispersion stabilization of the dispersed and raising of homogeneous in respective field of application.
When preparing the flowing molten iron body of different application purpose, wish to solve the range problem of response and temperature.Have the higher magnetization (or can under higher temperature, use) because wish the flowing molten iron body, do not wish that so those flowing molten iron bodies sharply reduce and response temperature by the magnetic property that makes them.When particulate became the superparamagnetism of flowing molten iron body standard state, such variation can take place.Super paramagnetic particulate is those particulates with permanent magnetic dipole moment, but fluctuates in time with respect to the dipole moment orientation of crystallographic axis.Superparamagnetism depends on volume, temperature and anisotropy or employed material.By considering energy, can derive equation about this tittle.Volume (Vp) when particulate or zone become superparamagnetism is provided by following formula: Vp=25kT/K, and wherein k is a Boltzmann constant, T is a kelvin degree, and k is the anisotropy of material constant.Use this equation,, can determine the temperature (magnetic transition temperature [blocking temperature]) when becoming superparamagnetism at particulate or zone for the given material of fixed volume.For example the fixed volume in ferritin is 8 nanometers.If (value is 45 * 10 only to have the crystalline anisotropy
5) the cobalt metal particle be the ball of diameter 8 nanometers, magnetic transition temperature then is 353 ° of K.By adjustment enter the iron egg from material, the response of wide region and temperature problem can be solved.
The main field of magnetic fluid medium of the present invention is magnetic carrier, transducer, pressure sensor, loud speaker, the optical switch of sealing, heat conduction, damping, separation, safe coding, printing ink and forms ordered structure.
Sealing
Flowing molten iron body of the present invention can be used to sealed bearing, the bearing in computer disc driver is used for example, and for example be described in the U.S. Patent No. 4673997 and 4692826, be incorporated herein their contents separately as a reference.Using the flowing molten iron body is such sealing pivot: use annular magnetic pole on the another side of axle, it is restricted flowing molten iron body therebetween by magnetic action.Flowing molten iron body as fluid gasket can make axle freely rotate.
Heat conduction
Flowing molten iron body of the present invention can be used as coolant, describes in detail and sees U.S. Patent No. 5462685, and its content is hereby incorporated by.A kind of method of cooling device is to attract the flowing molten iron body near described equipment under the action of a magnetic field.When the flowing molten iron body near equipment and when being warming to temperature and being higher than its Curie point, magnetized sizable part will lose magnetism and be replaced by fluid colder, that have more magnetic.Therefore the loop that forms convection current makes apparatus cools.
Damping
Flowing molten iron body of the present invention can be used as resisting medium, describes in detail and sees U.S. Patent No. 4123675, and its content is hereby incorporated by.Can influence the viscosity of flowing molten iron body by applying outside magnetic field.An example is to be closed in outstanding axle or the suspension spring that is full of the flowing molten iron body in the chamber.By applying the external magnetic field, the viscosity of flowing molten iron body increases so the free movement of axle and spring reduces.With such method, the external magnetic field can form the part loop, effectively the vibration of damping axle or spring or motion.
Safe coding/printing ink
For safe coding, can use flowing molten iron body of the present invention as magnetic ink printing and stored information, or provide only magnetic signature for signing banker's check or other important files or project.Simultaneously, use by the printing ink that in painted carrying object, disperses the flowing molten iron body, just can be used as to deposit by calutron.
Transducer
Flowing molten iron body of the present invention can be used as flowing molten iron body transducer, and its detailed description is for example seen U.S. Patent No. 4361879, and its content is hereby incorporated by.For example, the underwater sound wave generator of being made up of flowing molten iron body of the present invention can be packed in the toroidal container, and described container has hard bottom and top and elastic cylindrical wall.Coil is connected to bulge and is connected to dc bias power with the generation bias magnetic field, HBIAS, it can make the magnetization of flowing molten iron body just in time reach capacity.The coil that connects two rightabouts windings of madial wall and lateral wall respectively is connected in series to ac signal which with the generation mM disodium hydrogen phosphate, HAC, and it can modulate HBIAS.Electric wire is distributed in the volume that the flowing molten iron body occupies equably.HAC gradient along its radial direction can provide the time dependent active force that puts on the flowing molten iron body.Last flowing molten iron body can be transmitted by the elastic wall of outside along moving of its radial direction, thereby the water around giving provides sound wave.
Pressure sensor
Flowing molten iron body of the present invention can be used as the flowing molten iron pressure sensor, and its detailed description is seen U.S. Patent No. 5429000, and its content is hereby incorporated by.For example, differential pressure pick-up comprises flowing molten iron health check-up survey element or iron core, and it can make the position response pressure reduction in taper magnetic field and change.Flowing molten iron body core is contained in the pipe and moves in the taper magnetic field vertical with the longitudinal axis of pipe.The magnetic field heart therein has maximum flux density, reduces gradually along diaxon from its center.Iron core is placed in the center in magnetic field, corresponding to zero pressure difference.Corresponding to non-zero differential pressure, iron core moves to the magnetic field position that clean the action of a magnetic field power equates with pressure reduction.The output signal that changes according to the iron core position that produces by detecting element is judged the position of iron core.In one embodiment, detecting element is a sensor coil, and it is positioned with the range of movement of covering iron core one end, or a pair of sensor coil of location respectively, to cover the range of movement at iron core two ends.Therefore flowing molten iron body core is as the removable nuclear core of sensor coil.When flowing molten iron body core moved, it can change the relative induction coefficient of sensor coil.One or a pair of sensor coil are connected in the bridge circuit, and described bridge circuit can produce the output signal that changes with induction coefficient and pressure reduction thus.
Loud speaker
Flowing molten iron body of the present invention can use in loudspeaker, for example description in U.S. Patent No. 5461677, and its content is hereby incorporated by.More particularly, can fill flowing molten iron body of the present invention between the air gap in the loudspeaker.The flowing molten iron body transmits heat from voice coil loudspeaker voice coil, and the damping of voice coil loudspeaker voice coil motion also can be provided, and therefore reduces the distortion of loudspeaker sound and makes its frequency response level and smooth.Explain that further see W.Bottenberg, L.Melillo and K.Raj are published in Audiotechnica association proceedings, 1980 the 28th volume January and February the 17th～25 page of combined issue paper " the loudspeaker design parameter depends on the performance of magnetic fluid ".The flowing molten iron body is exceedingly useful in loud speaker, and it can make their voice coil loudspeaker voice coil move relatively large distance, for example in response to low-frequency woofer and time woofer.For example see that L.Melillo and K.Raj are published in audion technic association proceedings, March the 29th in 1981 was rolled up the 3rd phase the 132nd～139 page paper " flowing molten iron body, a kind of means of controlling the woofer design parameter ".
Optical switch
Flowing molten iron body of the present invention can be used as optical switch and uses, for example description in U.S. Patent No. 4384761, and its content is hereby incorporated by.In more detail, use controllable magnetic field to influence position, shape and the density distribution of flowing molten iron body, the flowing molten iron body can cause or stop the optical coupling between the light path by the following method like this: cause waveguide (as optical fiber) motion by physical method, or itself shift-in or shift out coupling regime between the light path physically.
Ordered structure
Flowing molten iron body of the present invention can be used to prepare ordered structure, for example description in U.S. Patent No. 5948321 and 6086780, and its content is hereby incorporated by.The film of flowing molten iron body in the film of the flowing molten iron body composition that applies magnetic field in response to the outside, can form orderly one-dimentional structure or two-dimensional lattice after applying the external magnetic field.Can make up many magneto-optical devices, it can utilize ordered structure to make optical diffraction, reflection and polarization with may command or foreseeable mode.These devices comprise: color monitor, monochromatic light switch and wavelength tunable filter.
When particulate feed in the encapsulate mode in the protein that has functional group, can attract antimatter or other charged parts, purpose is to extract pollutant with magnetic means from waste liquid stream.
In all applications, the present invention has utilized its following beneficial characteristics: adjustable magnetic property, single dispersiveness and can be present in ability in the multiple carrying object.
Below with reference to appended non-limiting example explanation the present invention.
Embodiment 1
This embodiment describes the method that is prepared apoferritin by horse spleen ferritin.The method for preparing apoferritin from the natural horse spleen of no cadmium ferritin is as follows: under nitrogen current, utilizing the reduction chelation of TGA (0.3M), is that 5.5 sodium acetate solution (0.2M) carries out dialysis (it is 10～14kD) to remove hydrated ferric oxide nuclear that molecular weight is accepted or rejected point to being buffered to pH.Subsequently sodium chloride solution (0.15M) is repeated dialysis to remove as-reduced hydrated ferric oxide nuclear fully from solution.
Embodiment 2
This embodiment is described in the method for preparing metallic iron in the apoferritin.Apoprotein joins in the AMPSO/ sodium chloride solution (0.1/0.4M) of removing bubble, and described solution is buffered to the protein working solution that pH8.5 obtains about 1mg/ml, and this liquid is heated to 60 ℃.Iron (II) [for example acetate] solution (1mg/ml) of removing bubble adds to be about up to the total atom number that adds gradually 500 atoms in each apoprotein molecule.It was stirred one day under room temperature and inert atmosphere.Use sodium borohydride reduction iron (II) salt to obtain metallic iron (0) subsequently.Last product can form iron granules solution, and described each particulate is all wrapped up by the ferritin shell.
Embodiment 3
This embodiment is described in the method for preparing metallic cobalt in the apoferritin.Apoprotein joins in the AMPSO solution (0.05M) of removing bubble, and described solution is buffered to the protein working solution that pH8.5 obtains about 1mg/ml, and this liquid is heated to 45 ℃.Cobalt (II) [for example acetate] solution (0.1M) of removing bubble adds to be about up to the total atom number that adds gradually 500 atoms in each apoprotein molecule.It was stirred one hour under this temperature and inert atmosphere.Use sodium borohydride reduction cobalt (II) salt to obtain metallic cobalt (0) subsequently.Last product can form cobalt particulate solution, and described each particulate is all wrapped up by the ferritin shell.
Embodiment 4
This embodiment is described in the apoferritin and prepares as yttrium cobalt (YCo
5) method of metal alloy.The preparation of described metal alloy is undertaken by the step identical with embodiment 2, and difference is: the ratio of yttrium of use (III) [for example acetate] and cobalt (II) [for example acetate] is 1: 5.Last product can form yttrium cobalt particulate solution, and described each particulate is all wrapped up by the ferritin shell.
Embodiment 5
This embodiment is described in the method for preparing in the apoferritin as cobalt platinum (CoPt) metal alloy.The preparation of described metal alloy is undertaken by the step identical with embodiment 3, and difference is: the ratio of platinum of use (II) [for example acetate] and cobalt (II) [for example acetate] is 1: 1, and pH value higher (9.0).Last product can form cobalt platinum particulate solution, and described each particulate is all wrapped up by the ferritin shell.
Embodiment 6
This embodiment is described in the apoferritin and prepares as Conjugate ferrite (CoFe
2O
3) the ferritic method of metal.Apoprotein joins in the AMPSO/ sodium chloride solution (0.1/0.4M) of removing bubble, and described solution is buffered to the protein working solution that pH8.5 obtains about 1mg/ml, and this liquid is heated to 60 ℃.Add gradually and remove the cobalt (II) [for example acetate] of bubble and the ratio of iron (II) [for example ammonium sulfate] is 1: 2 a solution, and use the Trimethylamine selective oxidation.Last product can form Conjugate ferrite particulate solution, and described each particulate is all wrapped up by the ferritin shell.
Embodiment 7
This embodiment describes and the product that obtains among the embodiment 2～6 is incorporated into carrying object but not method in the natural aqueous carrying object.Product among the embodiment 2～4 mixes with oleic acid as surfactant at 1: 100, and stirs 24 hours, and is dry in the rotation vacuum equipment, then suspends in kerosene again.
Claims (13)
1. magnetic fluid medium that contains multiple iron or ferrimagnetism particulate, the full-size of each particulate is no more than 100 nanometers, and described particulate is by following method preparation: it is included in the step that forms described particulate in the organic macromolecule shell.
2. magnetic fluid medium according to claim 1, wherein the full-size of iron or ferrimagnetism particulate is no more than 50 nanometers.
3. magnetic fluid medium according to claim 1, wherein the full-size of iron or ferrimagnetism particulate is no more than 15 nanometers.
4. according to claim 1,2 or 3 described magnetic fluid media, wherein iron or the maximum sized variation of ferrimagnetism particulate are no more than about 10% in the fluid.
5. according to claim 1,2 or 3 described magnetic fluid media, wherein iron or the maximum sized variation of ferrimagnetism particulate are no more than about 5% in the fluid.
6. according to the magnetic fluid medium of aforesaid arbitrary claim, wherein each iron or ferrimagnetism particulate are encased in the organic macromolecule that wherein forms described particulate.
7. according to arbitrary magnetic fluid medium of claim 1～5, wherein the organic macromolecule shell can be removed and the remaining not nanoparticle of parcel.
8. according to arbitrary magnetic fluid medium of claim 1～5, the shell of organic macromolecule can be carbonized the carbon-coating that surrounds nanoparticle nuclear to provide.
9. according to the magnetic fluid medium of aforementioned arbitrary claim, wherein organic macromolecule is the molecule of molecular weight more than 1500kD or the aggregate of molecule.
10. according to the magnetic fluid medium of aforementioned arbitrary claim, wherein organic macromolecule is to have the suitable hole that holds nanoparticle or the protein of through hole.
11. according to the magnetic fluid medium of claim 10, wherein organic macromolecule is an apoferritin matter.
12. according to the magnetic fluid medium of aforementioned arbitrary claim, wherein iron or ferrimagnetism particulate are metal, metal alloy or M-type or ferrospinel.
13. application as the flowing molten iron body of fluid media (medium), it comprises multiple iron or ferrimagnetism particulate, the full-size of each particulate is no more than 100 nanometers, and described particulate prepares by following method: it is included in the step that forms described particulate in the organic macromolecule shell.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9927911.9 | 1999-11-25 | ||
| GBGB9927911.9A GB9927911D0 (en) | 1999-11-25 | 1999-11-25 | Magnetic fluid |
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| Publication Number | Publication Date |
|---|---|
| CN1399783A true CN1399783A (en) | 2003-02-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN00816121A Pending CN1399783A (en) | 1999-11-25 | 2000-11-27 | Magnetic fluid |
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| Country | Link |
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| EP (1) | EP1232503A1 (en) |
| JP (1) | JP2003515921A (en) |
| KR (1) | KR20030007383A (en) |
| CN (1) | CN1399783A (en) |
| AU (1) | AU2380801A (en) |
| BR (1) | BR0015816A (en) |
| CA (1) | CA2392381A1 (en) |
| GB (1) | GB9927911D0 (en) |
| MX (1) | MXPA02005229A (en) |
| WO (1) | WO2001039217A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338615A (en) * | 2013-06-14 | 2013-10-02 | 成都艾迈计算机辅助工程有限责任公司 | Cooling device and method with function of noise reduction |
| CN105845496A (en) * | 2016-05-24 | 2016-08-10 | 汕头大学 | Magnetic fluid travel switch and combination method thereof |
| CN105845497A (en) * | 2016-05-24 | 2016-08-10 | 汕头大学 | Magnetic fluid switch with copper nano particles and distributed combination method |
| CN105869930A (en) * | 2016-05-24 | 2016-08-17 | 汕头大学 | Magnetofluid microcontrol knob and combining method thereof |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100490472B1 (en) * | 2002-06-04 | 2005-05-19 | 충남대학교산학협력단 | Carbon nanotubes synthesis method using magnetic fluids |
| GB2393729A (en) * | 2002-10-04 | 2004-04-07 | Nanomagnetics Ltd | Semiconductor nanoparticles |
| GB2393728A (en) * | 2002-10-04 | 2004-04-07 | Nanomagnetics Ltd | Magnetic nanoparticles |
| ES2304096B1 (en) * | 2003-11-26 | 2009-05-07 | Hoeganaes Corporation | SUSPENSIONS OF METALURGICAL POWDER COMPOSITIONS AND ARTICLES AND METHODS THAT USE THESE COMPOSITIONS. |
| JP3912391B2 (en) | 2004-05-26 | 2007-05-09 | ソニー株式会社 | Metallic magnetic nanoparticles and production method thereof |
| EP1646056A1 (en) * | 2004-10-09 | 2006-04-12 | European Central Bank | Security document on which data can be stored and method and apparatus for reading data from and writing data on the security document |
| EP1646057A2 (en) | 2004-10-09 | 2006-04-12 | European Central Bank | Security document and method for identification and/or authentication of a security document |
| EP2915991A1 (en) * | 2014-03-07 | 2015-09-09 | Continental Automotive GmbH | Electromagnetically actuatable fluid injection valve |
| DE102019219262B4 (en) * | 2019-12-10 | 2022-08-04 | Robert Bosch Gmbh | Sensor device, data acquisition system and method for evaluating work processes |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5512332A (en) * | 1985-10-04 | 1996-04-30 | Immunivest Corporation | Process of making resuspendable coated magnetic particles |
| NL1008528C2 (en) * | 1998-03-09 | 1999-09-10 | Univ Utrecht | Ferromagnetic particles. |
-
1999
- 1999-11-25 GB GBGB9927911.9A patent/GB9927911D0/en not_active Ceased
-
2000
- 2000-11-27 EP EP00987559A patent/EP1232503A1/en not_active Withdrawn
- 2000-11-27 KR KR1020027006645A patent/KR20030007383A/en not_active Application Discontinuation
- 2000-11-27 AU AU23808/01A patent/AU2380801A/en not_active Abandoned
- 2000-11-27 CN CN00816121A patent/CN1399783A/en active Pending
- 2000-11-27 CA CA002392381A patent/CA2392381A1/en not_active Abandoned
- 2000-11-27 WO PCT/GB2000/004517 patent/WO2001039217A1/en not_active Application Discontinuation
- 2000-11-27 BR BR0015816-0A patent/BR0015816A/en not_active IP Right Cessation
- 2000-11-27 JP JP2001540794A patent/JP2003515921A/en active Pending
- 2000-11-27 MX MXPA02005229A patent/MXPA02005229A/en unknown
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338615A (en) * | 2013-06-14 | 2013-10-02 | 成都艾迈计算机辅助工程有限责任公司 | Cooling device and method with function of noise reduction |
| CN103338615B (en) * | 2013-06-14 | 2016-05-18 | 成都艾迈计算机辅助工程有限责任公司 | A kind of cooling device and method that reduces noise |
| CN105845496A (en) * | 2016-05-24 | 2016-08-10 | 汕头大学 | Magnetic fluid travel switch and combination method thereof |
| CN105845497A (en) * | 2016-05-24 | 2016-08-10 | 汕头大学 | Magnetic fluid switch with copper nano particles and distributed combination method |
| CN105869930A (en) * | 2016-05-24 | 2016-08-17 | 汕头大学 | Magnetofluid microcontrol knob and combining method thereof |
| CN105845496B (en) * | 2016-05-24 | 2018-01-30 | 汕头大学 | A kind of magnetic fluid travel switch and combinations thereof method |
| CN105845497B (en) * | 2016-05-24 | 2018-04-24 | 汕头大学 | A kind of magnetic fluid switch with copper nano particles and distributed combined method |
| CN105869930B (en) * | 2016-05-24 | 2018-05-18 | 汕头大学 | A kind of magnetic current body minisize control handle and combinations thereof method |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20030007383A (en) | 2003-01-23 |
| BR0015816A (en) | 2002-07-16 |
| GB9927911D0 (en) | 2000-01-26 |
| AU2380801A (en) | 2001-06-04 |
| EP1232503A1 (en) | 2002-08-21 |
| WO2001039217A1 (en) | 2001-05-31 |
| JP2003515921A (en) | 2003-05-07 |
| CA2392381A1 (en) | 2001-05-31 |
| MXPA02005229A (en) | 2003-09-25 |
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