92results about How to "Precise control of stoichiometric ratio" patented technology

The invention provides a self-propagating high-temperature rapid one-step synthesis thermoelectric material powder with nanostructure Cu2Se method. The method includes: preparing stoichiometry of Cu powder and Se powder as 2 to 1 as raw materials, evenly mixing Cu powder with Fe powder to have reactants, adopting direct detonating or constant temperature detonating to trigger self-propagating reaction, natural cooling after reaction achievement and acquiring thermoelectric material powder with nanostructure Cu2Se. The method has the advantages of adoption of self-propagating high-temperature synthetic process, reaction for a short time, simple technique, low facility requirement, low energy consumption and environment friendliness. Further, stoichiometry of products is controlled accurately. Even distribution nanostructure is formed at normal positions.

The present invention relates to the process of preparing micron level SiO2 aerogel ball as the stuffing of chromatographic column for separating biological macromolecule. The process includes the following steps: preparing alcohol sol of SiO2 via mixing silicon gel and nitric acid in the volume ratio of 1 to 0.5-20, and adding anhydrous ethanol; mixing n-heptane, span-80, Tween-85 and n-butanol in certain volume proportion through stirring to obtain oil phase; adding the sol of SiO2 into the oil phase in certain volume ratio to form W/O emulsion; stirring, adding concentrated ammonia water to alkaline for depositing gel, further stirring, and liquid-solid separation to obtain SiO2 gel microballoon; washing with acetone and drying to obtain micron level SiO2 aerogel ball. The process has normal pressure, easy control, low cost, and other advantages.

The invention relates to a method for preparing a ternary high-nickel positive electrode material by employing a sol-gel self-propagating combustion method. The ternary high-nickel positive electrode material is LiNi<1-x-y>CoxAlyO2 (1-x-y is greater than 0.5, x is smaller than 1 and greater than 0 and y is smaller than 1 and greater than 0). The method comprises the steps of mixing and dissolving a lithium source, a nickel source, a cobalt source and an aluminum source into deionized water, adding glutamic acid and sodium fluoride to obtain a mixed solution; preparing dry gel from the mixed solution; carrying out heating and heat preservation, and carrying out complete self-propagating combustion on the dry gel to generate fluffy powder; and carrying out heat treatment on the powder to prepare lithium nickel cobalt aluminate positive electrode material. Sol-gel self-propagating combustion is carried out to prepare the lithium nickel cobalt aluminate by employing a glutamic acid as water-soluble gel and sodium fluoride as a catalyst. According to the method, the rate capability of the material can be improved, the cycling stability of the material is improved and the first cycling specific discharge capacity reaches 270-320mAh/g; and meanwhile, the requirements on heat treatment equipment can be reduced and the method has a good application prospect.

A method for preparing positive electrode multielement active material containing lithium / manganese composite oxide includes directly using lithium hydroxide coprecipitation to prepare M ( OH )2 , mixing it with lithium salt in grinding , forming plate by pressing , prebaking , cooled ball grinding , forming plate by pressing and backing . In the method , applied nickel salt is nickel acetate or nickel nitrate , applied cobalt salt is cobalt acetate or cobalt nitrate, applied manganese salt is manganese nitrate or manganese acetate and applied lithium salt is lithium carbonate or lithium acetate .

The invention belongs to the technical field of energy materials and in particular relates to a trace Cu-doped Bi2S3-based thermoelectric material. In the thermoelectric material, metal simple substance Bi and Cu powder with the purity of 99.99 percent and simple substance S powder serve as raw materials, the thermoelectric material is prepared according to a chemical general formula of CuxBi2-xS3, wherein x is mole fraction of a Cu component and x is more than or equal to 0.001 and less than or equal to 0.05, and the thermoelectric material is prepared into a block material by combining a discharge plasma sintering technology and a mechanical alloying method. By the method, the trace Cu-doped Bi2S3-based block thermoelectric material can be easy and convenient to prepare, trace Cu is introduced into a Bi2S3 lattice, the carrier concentration of a sample is improved, a power factor is optimized, a Cu-S nano deposition coherent with a substrate structure is formed, and the thermal conductivity is greatly reduced; therefore, the thermoelectric performance of the Bi2S3-based block material can be greatly improved.

The present invention discloses a solid spherical Li[Ni0.8Co0.1Mn0.1]O2 positive electrode material precursor preparation method. According to the method, a nickel compound, a cobalt compound and a manganese compound are matched according to a stoichiometric ratio to prepare a solution having uniform components, the solution is subjected to atomization through an ultrasonic atomizer to form droplets, and the whole atomization thermal decomposition process is rapidly completed, such that component segregation of the droplets does not occur timely so as to ensure component distribution uniformity of the Li[Ni0.8Co0.1Mn0.1]O2 precursor; and regular spherical particles are formed after the droplets are dried, agglomeration is less, and the subsequent washing and grinding is not required, such that high purity of the product is ensured so as to obtain the Li[Ni0.8Co0.1Mn0.1]O2 precursor with good sphericity. The method has the following advantages that: the preparation process is simplified, the stoichiometric ratio of the components can be precisely controlled, the prepared powder has high purity, and the Li[Ni0.8Co0.1Mn0.1]O2 material with an excellent electrical performance is easily prepared after sintering.

The invention relates to a silver, gold nano particle distributed silicon dioxide optical thin-film and a preparation method thereof, belonging to the field of metal nano particle and inorganic non-metallic composite material. In the invention, the method of sol-gel is adopted to prepare simple substance metal nano particle distributed silicon dioxide Ag<x>Au<y>/(SiO2)<1-x-y> composite thin-film, the materials are ethyl orthosilicate, silver nitrate, chloroauric acid, absolute ethyl alcohol and distilled water; the preparation steps are as follows: configuring Aga<>/(SiO2)<1-a>, Aub/(SiO2)<1-b> sol with mol fraction a ranging from 0.02-0.9, mol fraction b ranging from 0.02 to 0.83; adopting a spin coater to coat Aga<>/(SiO2)<1-a>, Aub<>/(SiO2)<1-b> film on a glass substrate in an alternating way to prepare silver, gold single substance metal particle distributed sull thin film with a laminated structure. The method has the advantages that in the process of preparing the silver, gold single substance metal particle distributed sull, stoichiometric proportion of the Ag<x>Auy<>/(SiO2)<1-x-y> thin film can be accurately controlled, silver and gold both exist in the form of single substance, two absorption peaks can be observed within specific range of wavelength, light absorption scope is expanded and fine nonlinear optical characteristics are provided.

The invention discloses a method for manufacturing a composite Nb3Al/Nb multi-core superconducting wire. The method comprises the following steps of: weighting Nb foil and Al foil based on a stoichiometric ratio of the Nb3Al; superposing the Nb foil and the Al foil and winding the Nb foil and the Al foil around a Nb rod, placing the Nb rod into a Nb tube, and drawing the Nb tube to a thin line of0.8-1mm to obtain a single-core wire; orderly placing the sections of the single-core wire into the Nb tube after cutting off the single-core wire to be multiple equal-length sections, and placing anequal-length Nb rod on the central axial line of the Nb tube; drawing and rolling the Nb tube to a circular or flat wire with the diameter of 1-2.5mm to obtain a multi-core wire; and cutting off the multi-core wire to short wires of 10cm, and carrying out a high-temperature treatment of 1900-2100 DEG C on the short wires for 0.05-0.2s by utilizing a pulse electric power under a vacuum condition to obtain the composite Nb3Al/Nb multi-core superconducting wires. The method disclosed by the invention has the advantages of short manufacturing period and high efficiency; in addition, the compositeNb3Al/Nb multi-core superconducting wire manufactured by the method has the advantages of compact connection, good uniformity, no separation situation, no impurity phase, and excellent superconducting performance.

The present invention belongs to the field of piezoelectric film material preparing technology, and is water base sol-gel process of preparing high Curie point piezoelectric film. Tetrabutyl titanate and nitrate and acetate of other metal cation as main material and glacial acetic acid and deionized water as main solvent are first prepared into stable sol; and the sol is coated and fast annealed to form the piezoelectric film with compact structure and homogeneous components. The piezoelectric film has excellent piezoelectric performance, Curie point as high as 435 deg.c, crystal grain size of 20-100 nm, effective piezoelectric coefficient d33*of about 80 pC/N, comparable with that of the PZT film, and thickness controllable in 0.15-1 micron. The piezoelectric film is suitable for various piezoelectric ferrite elements and devices used in high temperature, and may find wide application in space, automobile and other industrial fields.

The invention discloses a Bi0.92Dy0.08Fe(1-x)MnxO3 ferroelectric film with a low coercive field and a preparation method of the film. In Bi0.92Dy0.08Fe(1-x)MnxO3, x is 0.01-0.05; the film is of a rhombohedral structure and is good in uniformity; the residual polarization intensity is 58.27-69.87 muC/cm<2>; the coercive field is 318-448kV/cm; the dielectric constant is 214.4-260.6. The preparation method comprises the following steps: dissolving bismuth nitrate, ferric nitrate, dysprosium nitrate and manganese acetate into a mixed solution prepared from ethylene glycol monomethyl ether and acetic oxide in a mixing manner, so as to obtain a precursor solution; spinning the precursor solution on a substrate; baking after spinning to obtain a dry film; annealing to obtain the Bi0.92Dy0.08Fe(1-x)MnxO3 film; repeatedly spinning the precursor solution, baking and annealing to achieve the required film thickness, so as to obtain the film. According to the invention, equipment requirements are simple, doping content is easy to control, and the ferroelectric properties of the BiFeO3 film can be greatly improved.

The invention discloses a nonstoichiometric ratio Bi-Ag-S series thermoelectric material and a preparation method, and belongs to the technical field of energy materials. The method for preparing the nonstoichiometric ratio Bi-Ag-S material provided by the invention is characterized in that: high-purity metal simple substance Bi, Ag powder and high-purity S powder are used as raw materials and are prepared according to a chemical general formula of Bi2-xAgxS3 and Bi2-xAg3xS3-y (wherein the x is the molar fraction of an Ag component, the value range of the x is more than or equal to 0.001 and less than or equal to 1, the y is the molar fraction of the lacking amount of a sulfur element, and the value range of the y is more than 0 and less than or equal to 1.5); and the raw materials are synthesized into compound powder by adopting a mechanical alloying method, and then the compound powder is sintered through discharge plasma to form blocks. The method can simply, conveniently and accurately prepare the nonstoichiometric ratio Bi-Ag-S series block material, control the thickness of material carriers and the category of main carriers through the nonstoichiometric ratio of the components, and improve the thermoelectric performance.

The invention discloses a preparation method of cubic pyrochlore phase nanofiber based on an electrospinning method and application. The method includes using dimethylformamide as a solvent, adding anappropriate amount of polyvinylpyrrolidone to form a Taylor cone in an electrostatic field by dropping, preparing a one-dimensional nano material by the electrospinning method under the action of liquid surface tension and the electric field, and removing organic matter residues by heating, heat preservation and cooling to obtain the cubic pyrochlore phase one-dimensional nano material. The doping process of other rare earth ions and the traditional double doping or multi-doping processes are avoided, and the preparation method is simple and practicable, good in repeatability and capable of meeting the batch production requirements. A green up-converting luminescent substrate involved is an oxide with good chemical stability, non-toxic, inexpensive and prone to meet industrial productionrequirements. The prepared one-dimensional pure pyrochlore phase nano material is expected to play an important role in the fields of display, anti-counterfeiting, biological detection, infrared sensors, solar photovoltaic devices and the like.

The invention discloses a microwave-assisted solvothermal synthesis method of I-III-VI semiconductor material nano-powder. The method comprises the following steps: adding metal salt and a sulfur source or selenium source into a beaker based on the mole ratio of an expected product, adding a solvent, evenly mixing and then transferring the obtained mixed solution to a microwave reaction kettle; after the reaction kettle is closed, heating the mixed solution to rated temperature in a microwave field, and performing heat preservation for rated time; and centrifugally washing the final product to obtain the target powder. In the method, the solvent is one or more of water, ethylenediamine, ethylene glycol, diamine and ethanol; the metal salt is the metal salt of Cu, In, Ga and Al; the sulfur source is thiourea or sulfur powder; and the selenium source is selenium powder or seleninic acid. The microwave-assisted solvothermal synthesis method has the beneficial effects that based on the heating and activation effect of the microwave field, reaction temperature is lowered and reaction time is shortened; and part of reaction that can not be made in the traditional high-pressure solvothermal synthesis process can be performed smoothly. The obtained semiconductor material nano-powder has the advantages of smaller grain size, pure phases, accurately controlled stoichiometric ratio of the phases and the like.

The invention relates to a silver nanoparticle-dispersed cobalt oxide functional thin film material and a preparation method, and belongs to the field of photocatalysis. The material is characterized in that the general formula of chemical compositions of the thin film material is Agx / (Co3O4) 1-x, wherein x indicates the mole fraction of constituent element of Ag, and x ranges from 0.01 to 0.85. In the process, cobalt nitrate and silver nitrate are used as raw materials, and ethylene glycol monomethyl ether is used as a solvent; a precursor solution with accurate stoichiometric proportion and uniform compositions is synthesized by chemical solution method, and film is coated on a glass substrate by a spin coater, and finally the Agx / (Co3O4) 1-x composite film is obtained by thermal decomposition and annealing. Silver nanoparticles are uniformly dispersed in a cobalt oxide matrix, and the diameter of the silver particle is 1- 500nm; and the film can observe the plasma resonance absorption peaks of metal particles at a wave band of 350-450nm, and the film has excellent photocatalytic properties under the irradiation of visible light.

The invention discloses a method for preparing a rare-earth ytterbium-erbium-doped pyrochlore-phase nanofiber and application of the nanofiber. The method comprises the following steps of taking dimethyl formamide as a solvent, adding polyvinylpyrrolidone, forming a Taylor cone through liquid drops under the action of an electrostatic field, preparing a one-dimensional nano material by means of anelectrostatic spinning approach under the action of liquid surface tension and the electric field, and removing organic matter in the processes of heating, heat preservation and cooling to prepare the cubic pyrochlore-phase one-dimensional nano material. The one-dimensional nanofiber has high dispersibility in water and a great photothermal effect under the irradiation of near-infrared light. Thepreparation method is simple, feasible and high in repeatability and can meet the requirement of batch production. A related photo-thermal material matrix is an oxide which is high in chemical stability, free of toxin and low in price and is easily dispersed in water, and the demands of photo-thermal therapy and industrial production can be met. The prepared one-dimensional pure pyrochlore-phasenano material is expected to play an important role in the treatment field of major diseases such as cancers and tumors.

The invention discloses a flexible honeycomb bimetallic nitride supercapacitor electrode and a preparation method, and relates to the technical field of supercapacitor electrode materials, and the preparation method comprises the following steps: dissolving cobalt nitrate and nickel nitrate in methanol, then adding 2-methylimidazole, and performing stirring to obtain a methanol solution of cobalt and nickel; sequentially putting hydrochloric acid, acetone, ethanol and deionized water into the flexible porous conductive substrate, performing ultrasonic cleaning, and performing vacuum drying; adding a flexible porous conductive substrate and a methanol solution of cobalt and nickel into an autoclave, carrying out heating reaction to obtain a Ni-Co LDH precursor sample grown on the substrate, carrying out cleaning and vacuum drying, then putting the Ni-Co LDH precursor sample into a tubular furnace, introducing a nitrogen source, carrying out heating and heat preservation reaction to obtain a Ni-Co-N porous film sample grown on the substrate, and thus obtaining the electrode. According to the invention, a solvothermal method is adopted for in-situ growth of the three-dimensional layered multistage porous honeycomb Ni-Co-N porous film on the flexible porous conductive substrate, and the porous film shows excellent cycling stability and ultrahigh rate capability when being used as a supercapacitor electrode.

The invention provides spherical spinel lithium titanate and a preparation method and an application thereof. The preparation method includes the following steps: successively dissolving cetyl trimethyl ammonium bromide and lithium acetate in absolute ethyl alcohol to obtain a mixed solution; slowly dripping butyl titanate into the mixed solution under magnetic force stirring to form a yellow transparent solution, and continuing to stir to form yellow transparent gel; aging the yellow transparent gel in the air to form white gel, drying the obtained white gel in the air at 100 DEG C to form a dry gel precursor; grinding the dry gel precursor, pre-sintering the dry gel precursor at 700-900 DEG C for 4 hours, and carrying out heat treatment at temperature of 700-900 DEG C for 12 hours to obtain the spherical spinel lithium titanate, and the spherical spinel lithium titanate can be applied in lithium ion battery cathode materials. The spherical spinel lithium titanate provided by the invention has the characteristics of high tap density, good processing performance, good compatibility with electrolyte, excellent electrochemical performance and the like, and is wide in preparation raw material source, low in cost, short in period, low in temperature, simple and reliable in process and easy to achieve industrial production.

The invention discloses a BiFe1-XMnXO3 ferroelectric film with high remnant polarization and a preparation method thereof, and x is equal to 0.02-0.08. The BiFe1-XMnXO3 ferroelectric film is of a twisty perovskite structure, belongs to a rhombohedral system, and is good in uniformity. At the frequency of 1kHz, the remnant polarization is 100-130.4mu C/cm<2>. The preparation method comprises the steps of: dissolving bismuth nitrate, ferric nitrate and manganese acetate in a mixed solution of ethylene glycol monomethyl ether and acetic anhydride according to a molar ratio of 1.05:(1-x) to obtain a precursor solution; and spinning the precursor solution on a substrate, homogenating and baking to obtain a dry film; annealing to obtain the BiFe1-XMnXO3 ferroelectric film, repeatedly carrying out the steps of spinning the precursor solution, baking, and annealing till a required film thickness is reached, thus obtainng the BiFe1-XMnXO3 ferroelectric film with high remnant polarization. The BiFe1-XMnXO3 ferroelectric film is simple in requirement of equipment, easily controllable in doping amount, and capable of greatly improving ferroelectric properties and dielectric properties of a BiFeO3 film.

The invention relates to a batch preparation method of pentatitanium trisilicate intermetallic compound powder. Si powder and Ti powder are weighed according to a mole ratio of 3: 5 as sintering raw materials; a Ti5Si3 compound is synthesized by adopting a vacuum sintering process; the sintering process comprises the following steps: the Si powder and the Ti powder, uniformly mixed, are put in a vacuum furnace, are heated to 1350-1450 DEG C for insulation, and are cooled to the room temperature along with the furnace; the sintering materials are added in anhydrous ethanol, and are put in a ball milling tank; Ar gas is used as shielding gas; the sealed ball milling tank is put in a high-energy planet ball mill; a wet ball milling method is used for refining; and vacuum drying and grinding are performed on obtained ball milling pulp to pass through a sieve of 130 meshes to obtain Ti5Si3 powder. The method overcomes the defects of easy generation of pollutions, complex machining process,low yield and the like in a casting method, a powder press sintering method, a quick solidification method and a self-propagating combustion method. No by-product is generated in the reaction process;the powder purity is high; meanwhile, the chemical ratios of products can be precisely controlled; the energy consumption is low; the particle sizes of the products are fine and uniformly distributed; the activity is high; the products can be prepared in batches; no pollution is generated; and the cost is reduced.

The invention discloses an all-oxide ferroelectric photodiode and a preparation method thereof, and the all-oxide ferroelectric photodiode comprises a substrate, the substrate is covered with an LSMOlayer, the LSMO layer is covered with a BFCO layer, and the BFCO layer is covered with an ITO layer. The LSMO layer is a La0. 7Sr0. 3MnO3 thin film which grows in an epitaxial mode, and the BFCO layeris a BiFe0. 7Co0. 3O3-delta thin film which grows in an epitaxial mode. Separation and efficient collection of photo-induced electron hole pairs in a device are promoted by utilizing ferroelectric polarization and the coupling effect of Schottky junction region barriers between electrodes, the modulation of photocurrent response and ferroelectric polarization on diode current is enhanced, the advantages of ferroelectricity and semiconductivity are both achieved, the large photocurrent response is achieved, and the polarization adjustability is good.

The invention discloses fluorescent powder, a preparation method thereof, and a luminescent device comprising the fluorescent powder. The chemical constitution of the fluorescent powder is AXZ3-xAl2LiyE3-y(DmNnO12-m-n), wherein A is one or more elements selected from Na, K, Rb or Cs; Z is one or more elements selected from Ce, Sc, Y, La, Gd, Tb or Lu; E is one or more elements selected from B, Al, In or Ga; D is one or two elements selected from F or Cl; x is no lower than 0 and no higher than 3; y is no lower than 0 and no higher than 3; n is no lower than 0 and no higher than m; m+n is lower than 12; and 2x+2y=m-n. The fluorescent powder provided by the invention has a novel chemical constitution, and has high luminescent intensity. With the fluorescent powder, a phenomenon of charge imbalance is prevented, and thus fluorescent powder luminescent intensity reduction is avoided.