111results about How to "Good crystallization" patented technology

A process for preparing the cubic silver nanocrystals includes such steps as proportionally dissolving surfactant and silver nitrate in organic solvent while stirring, slowly adding to an organic solvent at 150-180 deg.C to obtain the saturated solution of Ag nanoparticles, continuous reacting, and slow cooling while stirring to obtain the sol of cubic silver nanocrystals. Its advantage is high purity and dispersity.

The invention relates to a preparation technology of a battery anode material and a related automobile battery and particularly discloses a preparation method of lithium ion battery anode material lithium manganate. The method comprises the following steps: using lithium source, Mn3O4 and nanoscale doping metal additive as raw materials for proportioning, then presintering Mn3O4 or the Mn3O4 processed by ball milling, mixing the presintered Mn3O4 with the mixture of lithium source and metal additive; performing the first sintering and second sintering to the mixed raw material; and finally classifying and screening the sintering product to obtain the spinel lithium manganate product with the required grain size. The invention also discloses an automobile lithium ion battery which is assembled by using the spinel lithium manganate prepared by the method of the invention as anode and using graphite as cathode. The preparation method of the invention has simple operation and environmental friend; and the prepared lithium manganate product has excellent product performance.

A process for preparing nano hydroxyapatite powder comprises the steps of, mixing Ca(NO3)-2-4H20 and NH4-2HPO-4 according to the mol ratio of Ca:P = 1.67-2.5:1, dissolving by charging distilled water, making the concentration of the Ca2++ ion to be 0.01-0.1 mol / L, charging aquadrate powder into the solution according the ratio of Ca(NO3)-2-4H2O : NH4-2HPO-4 = 1:5-12, conducting sound chemo synthesis through multiple frequency phonochemical generator, filtrating and washing the suspending liquid, placing the filtered material into vacuum drying oven for drying at the temperature of 80-100 deg. C, thus the nano hydroxyapatite powder can be obtained.

A multiple elements doped anatase-type TiO2 sol photocatalyst features that its solvent is water or the mixture of water and unitary or binary alcohol, and its sol contains non-metal doped anatase-type TiO2 nanoparticles, and has a formula: TiO2-x-yAxBy, where x=0.0-0.1, y=0.0-0.1 and A or B is one or more of non-metal halogens or N-family elements. Its preparing process includes such steps as hydrolyzing organic or inorganic Ti source, doping, dispergating, and hydrothermal crystallizing.

The invention relates to a method for preparing a neutral mixed crystal nano TiO2 hydrosol with high stability, belonging to the photocatalytic active nano titanium dioxide material preparation process technical field. The method comprises the main steps that: 1. a titanium compound is hydrolyzed by aqueous slkali and deposited, filtered and washed; 2. products obtained are added in an acid solution and peptized at the temperature of between 60 and 100 DEG C, and added with a certain amount of SiO2 sols used as a stabilizer and metal salt used as a doping agent to be continuously reacted for a period of time; 3. the mixture is added with alkaline liquor for adjusting the pH value to between 7 and 8; 4. the mixture is filtered and washed, and filter cakes are dissolved in a certain amount of water and redispersed, and finally the neutral mixed crystal nano TiO2 sol with high stability is obtained. The TiO2 compound hydrosol prepared by the invention is neutral and has good transparency and stability, and the crystal form ratio of anatase and rutile is controllable, and the spectral response range is wide; the TiO2 hydrosol prepared by the invention is convenient in coating operation; moreover, the hydrosol can utilize the solar energy to complete sewage disposal, air purification, antibiotic treatment and glass film coating treatment, etc.

The invention discloses a preparation method of a graphene supported ferriferrous oxide nanocomposite, comprising the following steps: preparing a precursor by deposition precipitation method, depositing ferric nitrate ninehydrate or ferric chloride hexahydrate on graphene in the form of iron hydroxide by using sodium hydroxide or ammonia to obtain black powder, washing and drying the obtained black powder, grinding the dried black powder, then calcining under the protection of argon, and then cooling, and reducing under the protection of a mixed gas of argon and hydrogen or argon and ammonia gas to obtain the graphene supported ferriferrous oxide nanocomposite. The preparation method is simple and stable. In the obtained composite, ferriferrous oxide is uniformly distributed on graphene and has good interface combination of the substrate graphene, thus the absorbing properties and the like of the composite as a functional material can be improved. The method also can be used for preparing carbon material supported ferriferrous oxide nanocomposites with different substrates by using carbon nanotube, graphite oxide and other carbon materials as the substrate.

The invention relates to a preparation method of a homodisperse carbon nano tube enhanced aluminium base composite material and belongs to the preparation technology of an aluminium base composite material. The method comprises the following steps: preparing catalyst precursor powder from nickel salt and aluminite powder by a dipping method; preparing Ni / Al catalyst by calcining the precursor powder, and then reducing the calcined precursor powder by utilizing hydrogen, or directly reducing the precursor powder by utilizing the hydrogen; carrying out catalytic pyrolysis reaction on the Ni / Al catalyst in a tubular furnace and the mixing gas of the introduced carbon source gas and carrier gas to prepare the composite powder of the carbon nano tube and aluminum; and preparing the homodisperse carbon nano tube enhanced aluminium base composite material block by carrying out cold pressing, sintering and hot extruding on the composite powder of the carbon nano tube and the aluminum. The invention has the advantages of simple and stable preparation process and promotion applicability; the obtained carbon nano tube is evenly dispersed on the surface of aluminium powder, and is well bonded with the interface of a substrate body; and the property of the aluminium base composite material is improved.

The invention discloses a p-n knot nano composite material in a special structure and a preparation method and application thereof, and belongs to the technical field of preparation of inorganic non-metal nano materials, environmental protection and solar energy utilization. The p-n knot material is a surface-modified (partially wrapped) nanoscale large energy gap n type semiconductor material (titanium dioxide, zinc oxide, stannic oxide and the like) by taking a low energy gap p type semiconductor material (cuprous oxide, cuprous sulfide, cadmium sulfide and the like) in a low-dimensional nano structure (spherical, polyhedral, linear and the like) as the inner core. By adopting a method of controlling hydrolysis of a metal salt, a lot of heterogeneous p-n knots are constructed on the surface of low energy gap p type semiconductor material in the low-dimensional nano structure. The p-n knot nano composite material can be directly used for solving the problem of decomposition of organic matters under visible lights, deactivation of microbial pathogens and efficient utilization of solar energy, particular the problem of low electron-hole separation efficiency of a single-component photocatalyst material.

The invention provides a monodisperse cerium oxide nanoparticle and a preparation method thereof. Monodisperse cerium oxide nano-powder with high crystallinity can be prepared by controlling the reaction speed in a way of taking a soluble cerium salt, nitrate and a dispersant as reaction raw materials, taking water as a solvent and taking nitrate as a mineralizing agent and by controlling the concentration of a cerium salt solution, the proportions of reaction raw materials, hydrothermal time and hydrothermal temperature under a hydrothermal condition, and effective regulation and control over the particle diameter of cerium oxide is realized. The cerium oxide nano-powder prepared with the method has the advantages of uniform size distribution, high dispersity, simple preparation process, no need of complex raw material equipment, easiness for operating, low cost and high repeatability.

The invention discloses a preparation method of carbon-coated cobalt metal nano-particles, which relates to a gaseous compound decomposition-based chemical plating by which reaction product of surface material is not preserved in a plating layer and only carbon is deposited, and is a method for decomposing ethyne and synthesizing carbon-coated cobalt metal nano-particles on potassium chloride carrier by means of chemical vapor deposition. The preparation method comprises the following steps: firstly, preparing cobalt-potassium chloride catalyst, then, synthesizing carbon-coated cobalt metal nano-particles, and finally, performing purification to obtain the carbon-coated cobalt metal nano-particles with purity of 95-99%. The preparation method overcomes the defects that the carbon-coated metal nano-particles synthesized by the existing technology have low purity, poor performance and low yield, and contains overmuch impurities, and the impurities are not easy to remove.

The invention discloses a method for preparing flame retardant epoxy resin from modified graphene, and relates to a method for preparing epoxy resin. The method comprises preparation of graphene oxide; preparation of octa-aminopropyl cage-like silsesquioxane; and modifying of epoxy resin with functionalized graphene, to be more specific, heating and melting the epoxy resin, mixing and curing the epoxy resin and the functionalized graphene to obtain modified epoxy resin. According to the method, the graphene oxide (GO) is prepared by modifying, silane coupling agent KH-550 is used as a raw material for preparation of the octa-aminopropyl cage-like silsesquioxane (ApPOSS), the modified graphene is prepared by grafting reaction of the GO and the ApPOSS, the modified graphene and EP are mixedand cured to improve the compatibility of the modified graphene with the epoxy resin, the modified graphene and the epoxy resin are compounded for preparation of an epoxy resin nanocomposite, and thecomprehensive effect is obvious.

The invention relates to a high-strength electric-control solid propellant which comprises the following components in percentage by mass: 10-20% of adhesive, 60-80% of main oxidizer, 5-20% of auxiliary oxidizer, 1-2% of crosslinking agent, 0.1-0.5% of coupling agent and 1-5% of fuel additive. The adhesive is water-soluble polyvinyl alcohol (PVA); the main oxidizer is hydroxylammonium nitrate (HAN); the auxiliary oxidizer is one or combination of ammonium nitrate (AN) and ammonium perchlorate (AP); the crosslinking agent is one or combination of boric acid and borax; the coupling agent is a silane coupling agent; and the fuel additive is one or combination of cyclodextrin, sodium alginate, polyvinylpyrrolidone (PVP) and gelatin. The normal-temperature tensile strength of the electric-control solid propellant can be obviously enhanced, and the maximum normal-temperature strength can reach 8 MPa or above. The electric-control solid propellant is suitable to be used as an attitude control or orbit control propellant with higher requirements for normal-temperature strength.

The invention provides aerated concrete prepared from coal ash-nanosilicon dioxide-silica fume as main siliceous materials. The aerated concrete comprises at least the following ingredients by weight: 80-150 parts of cement, 180-270 parts of lime, 15-25 parts of gypsum, 550-650 parts of coal ash, 30-45 parts of nanosilicon dioxide, 35-50 parts of silica fume, 30-40 parts of solid water reducers, 1.5-3 parts of retarders, 1.0-1.5 parts of foaming agents, 1.2-1.7 parts of foam stabilizers, 2.1-3.0 parts of water glass, 1.6-2.5 parts of oleic acid-triethanolamine binary mixed solutions and 400-500 parts of water. According to the invention, the aerated concrete is low in cost and simple in preparation technology, and improves the crystalline degree and crystalline quantity of an aerated concrete hydration product tobermorite, so that the thermal insulation property and strength of the aerated concrete are improved.

The invention relates to a method for preparing a composite heterostructure of zinc oxide nano rods and a silver micron plate. The method includes: utilizing dextran sulphate sodium as regulating agent to prepare a perforated silver micron plate in a reaction system of silver nitrate and an ascorbic acid solution of water and methanamide; depositing zinc oxide seed crystals on the silver micron plate, coating the silver micron plate with the deposition of the zinc oxide seed crystals on an electric-conducting glass sheet in a rotating manner, cleaning, drying, placing the electric-conducting glass sheet in an ethanol solution of hexamethylene tetramine and zinc nitrate to grow a zinc oxide nano rod array on the silver micron plate, fully cleaning with water, and naturally drying to obtain the finished product. The product prepared by the method is a high-level composite heterostructure with the zinc oxide nano rod array growing on the perforated silver micron plate, wherein the diameter of the silver micron plate is about 4 microns, and the size and the structure of the zinc oxide nano rod array are adjustable and controller. The method for preparing the composite heterostructure of the zinc oxide nano rods and the silver micron plate is structurally controllable, good in repeatability and stable in product property, and has excellent photocatalytic performance.

The invention discloses a preparation method of size-controllable nanoscale cubic-phase super-fine barium titanate powder. Relatively cheap titanium tetrachloride is used for preparing a titanium precursor solution TiClO2 through hydrolysis, the precursor solution is dropwise added into a mineralizing agent and dispersant solution, and continuous stirring is performed to obtain a titanium precursor gel solution; then centrifugal gel washing is performed to remove chloride ions, the prepared H4TiO4 gel and barium hydroxide or barium nitrate are grinded and dispersed with water and a dispersant according to a certain proportion to prepare mixed dispersed slurry, the mixed dispersed slurry is put into a reaction kettle for hydrothermal reaction, and then washing and drying are performed to obtain the nanoscale cubic-phase super-fine barium titanate powder good in dispersion and centralized in particle size, the average particle size of the power is smaller than 100 nm, and the specific surface area is within the range of 12.5-15.0 m<2> / g.

The invention relates to the field of semiconductor yield improvement, in particular to a crystal edge cleaning device. According to the crystal edge cleaning device, the front face and the back face of the crystal edge of a wafer can be processed at the same time, residual film structures and various impurities on the crystal edge can be effectively removed, meanwhile, the crystalline degree of the crystal edge can be improved, then, the probability that the crystal edge is the defect source is reduced, and great help is provided for improving the product yield.

The present invention discloses chemical preparation process of nanometer polyethylene thienyl dioxide, and belongs to the field of conducting material preparing technology. The preparation process includes the following steps: compounding 0.5-1.2 mol / L concentration mixed solution of camphor sulfonic acid and ethylene thienyl dioxide, compounding 0.47-2.80 mol / L concentration solution of ferric trichloride, mixing them to initiate polymerization reaction at 0-5 deg.c; centrifugally separating and washing the product with deionized water to neutral, vacuum drying at 50-80 deg.c for 6-24 hr to obtain the navy blue polyethylene thienyl dioxide powder as the product. The preparation process is simple and environment friendly, and the prepared nanometer polyethylene thienyl dioxide has high conductivity, high crystallization degree and other physical characteristics, and possesses latent application in photoelectronic device field.

The invention relates to a composite intermediate layer capable of prolonging the service life of a titanium-based lead dioxide anode. The expression of the composite intermediate layer is alpha-PbO2-(Nano WC). According to a preparation method of the intermediate layer, the alpha-PbO2-(Nano WC) composite intermediate layer is prepared by adopting an anode composite electrodeposition approach in aPbO alkaline plating solution into which platinum-like nano WC particles with great electricity conduction performance are added. The composite intermediate layer can be used as a titanium-based leaddioxide anode intermediate layer. The alpha-PbO2-(Nano WC) composite intermediate layer is prepared on a titanium substrate which is pretreated by oil removal and acid etching, then subjected to flowing water washing and neutralization and put into a lead nitrate bath liquid, and a beta-PbO2 active layer is electrodeposited on the alpha-PbO2-(Nano WC) composite intermediate layer by the anode, sothat the coating anode of a Ti / alpha-PbO2-(Nano WC) / beta-PbO2 structure is finally obtained. The preparation method is an effective method for controllably constructing a titanium-based metal oxide electrode by utilizing electrochemical co-electrodeposition to prepare the composite intermediate layer, not only the advantages of a composite multifunctional coating be fully exerted, but also a firmcoating electrode base can be obtained through preparation of the composite intermediate layer, and correspondingly long-term reliable use of the titanium-based metal oxide electrode is achieved.

The invention discloses a method for preparing a comb-shaped macromolecular solid-solid phase change material. The method comprises the following processes of: adding at least one of macromolecular compounds containing hydroxy, amino or carboxyl into a dispersion liquid to form a uniformly dispersed suspension, heating the suspension to the temperature between 50 DEG C and 95 DEG C to react at the stirring speed of 50-400r / min, adding a catalyst or an initiator in an amount which is 0.1-2 percent of the mass of the macromolecular compound, then adding (methyl) acrylic n-alkyl ester in an amount which is 30-300 percent of the mass of the macromolecular compound, reacting for 6-24 h at the same stirring speed, washing the obtained reaction product for three times with deionized water and anorganic solvent respectively, and drying the reaction product to obtain the comb-shaped macromolecular solid-solid phase change material. The dispersion liquid is water, formic acid, acetic acid, methanol or ethanol; and the organic solvent is capable of dissolving the (methyl) acrylic n-alkyl ester and poly (methyl) acrylic n-alkyl ester.

The invention discloses a preparation method of a titanium-based PbO2 anode with a conductive ceramic membrane intermediate layer based on in-situ thermal reaction. The method comprises the followingsteps (1), a titanium material is anodized; (2), a Ti4O7-TiN ceramic membrane is prepared by high temperature thermal reaction under hydrogen atmosphere; and (3), a beta-PbO2 active layer is electrodeposited on an anodic, and finally a Ti / Ti4O7-TiN / PbO2 coating anode is prepared. According to the method, the titanium dioxide-titanium nitride composite ceramic membrane with good conductivity, highcorrosion resistance and high strength (hardness) is obtained by utilizing electrochemical anodic oxidation and in-situ high-temperature thermal reduction, the composite ceramic membrane serves as a bottom layer to prepare the Ti / Ti4O7-TiN / PbO2 coating anode through anodic electrodeposition, and a novel titanium-based PbO2 coating anode with long service life and low energy consumption is finallyobtained; and moreover, the good conductivity of an electrode enables cell voltage in the electrochemical preparation and electrolysis processes of the electrode to be remarkably reduced, and the electric energy consumption can be saved.

The invention relates to a preparation method of ultra-fine particle of submicron barium titanate powder. The preparation method comprises the following steps of preparing a nano titanium source; removing chlorine ions in the titanium source; preparing a collosol; preparing cubic phase barium titanate sizing agent in a reaction kettle; washing the cubic phase barium titanate sizing agent; preparing tetragonal phase barium titanate powder aggregating preliminarily, and preparing tetragonal phase barium titanate powder. The preparation method has the advantage that the tetragonal phase barium titanate particle synthesized in the method is uniform, is complete, has the dispersibility of 1.01-1.2, is controllable in average particle size and specific surface area, has the tetragonal phase crystallization rate greater than or equal to 1.010, and is highly pure. The preparation method overcomes the defects of existing industrial production process, improves the yield of base powder of MLCC products, and improves the production efficiency.

The invention relates to a method for preparing trihydroxy cobalt hydroxide, which comprises the following steps of: adding an appropriate amount of cobalt chloride and hexadecyl trimethyl ammonium chloride into mixed liquor of N,N-dimethylformamide and deionized water, and slightly stirring to form red uniform solution; adding 30 weight percent of hydrogen peroxide, fully mixing, screwing a reaction kettle, putting into a drying box, and standing at the temperature of 150 DEG C; and performing centrifugal separation on a product, and washing for multiple times to obtain the product. Comparedwith the prior art, the method has the advantages that: a new type of trihydroxy cobalt hydroxide is synthesized by a hydrothermal method, is well crystallized, and has controllable size and structure, high purity and definite components; the preparation method is simple and practicable, and high in operability and repeatability; and the powdered product has stable performance, can be stored in air at room temperature for a long time, and can be widely used for the fields of energy batteries, catalysis, electrochemistry, gas sensors, magnetics and the like.

The invention discloses a method for preparing a comb-shaped polymer solid-solid phase change material. The method comprises the following processes of: dissolving 1-3 kinds of 1-n-alkanols into 2-4-times of the 1-n-alkanols of solvent uniformly, adding one of diisocyanates with the same mole number as the 1-n-alkanols at the speed of 1-50mL / min, and reacting for 2-4 hours in a solvent of 30-90 DEG C under stirring to form a prepolymer solution; dissolving dried polyvinyl alcohol into the solvent, adding a dibutyltin dilaurate catalyst -assisted 0.01-1 percent of the mass of the polyvinyl alcohol, and adding the prepolymer solution at the speed of 5-50mL / min, wherein the molar ratio of the prepolymer to the polyvinyl alcohol is 1,000:1-2,500:1; and controlling the reaction temperature at a temperature 30-90 DEG C, reacting for 6-12 hours under stirring, then washing the obtained product, and drying the product to obtain the comb-shaped polymer solid-solid phase change material.

The invention discloses a method for preparing Al2O3 composite powder with uniformly dispersed carbon nanotubes by an in-situ synthesis process, which comprises the following steps: proportionally preparing aluminum nitrate, nickelous nitrate and citric acid into a solution, and heating and calcining the obtained solution to initiate the combustion reaction, thereby obtaining the NiAlxO3x+1 solid solution catalyst precursor powder; and putting the obtained solid solution in a pipe furnace, introducing a gas mixture containing methane, hydrogen and nitrogen, heating to reaction temperature, reacting for some time, and cooling to obtain the Al2O3 composite powder with uniformly dispersed carbon nanotubes. The content of the catalyst nickel is controlled to control the content of the carbon nanotubes; and meanwhile, the invention solves the problem that the carbon nanotubes can not be easily dispersed in the ceramic matrix, so that the nanotubes are uniformly dispersed in the product.

The invention relates to a method for preparing K0.5Na0.5NbO3 superfine powder at low temperature; firstly, the powder of reactants: NB2o5, Na2CO3 and K2CO3, is mixed, and then the mixed powder is added with urea, an incendiary agent, which accounts for 80%-200% weight of the mixed powder; secondly, the mixture is put in a vessel and calcined at 550 DEG C-750 DEG C for more than 6 hours; finally, the calcined product is porphyrized to obtain the K0.5Na0.5NbO3 superfine powder. The K0.5Na0.5NbO3 powder prepared by the invention has high degree of crystallinity, fine particle size, narrow grain size distribution, little agglomeration, good uniformity, and the like; meanwhile, the adoption of urea can lower synthetic temperature; furthermore, the method of the invention has simple technical process and equipment, convenient operation, inexpensive and easily available raw materials and low preparing cost of the powder and is suitable for industrial production; therefore, the method has strong practicability.

The invention discloses a method for preparing novel titanium-based PbO2 anode with low energy consumption and long service life by adding a nickel composite intermediate layer. Through performing cathodic electrodeposition on the surface of a titanium plate which is subjected to oil removal and acid etching pretreatment by adding particles with good conductivity and oxygen evolution catalytic activity, such as MnO2, Co3O4, into the nickel plating deposition solution to prepare the composite intermediate layer, then a beta-PbO2 active layer is electrodeposited on the nickel composite intermediate layer, and Ti / Ni-Co3O4(MnO2) / PbO2 titanium-based PbO2 coating anode is obtained. Due to the fact that the composite intermediate layer effectively prevents corrosive medium and active oxygen fromtransferring to the anodic titanium substrate to generate TiO2 to lead to anode failure reaction, good physical barrier and reaction oxygen barrier effects are achieved, and the service life of the anodic electrode is prolonged.; meanwhile, the high-conductive nickel composite intermediate layer helps to obviously reduce the cell voltage in the electrochemical degradation process and reduce the energy consumption.

The invention discloses an onion shaped fullerene purification process comprising the steps of acid liquor thermal treatment, potassium dichromate oxidization, extraction thermal treatment, purification through vacuum heat treatment and ball grinding.

The invention relates to the technical field of new materials, in particular to olivine-added lightweight ceramsite sand and a preparation process thereof. The lightweight ceramsite sand comprises thefollowing raw materials in percentage by weight of 45-55 wt% of bauxite, 30-40wt% of flint clay, 7-12wt% of olivine, 1-6 wt% of magnesium slag and 1-5 wt% of manganese ore powder, wherein the bauxiteis the medium-low grade bauxite; the medium-low grade bauxite is used as the main material, so that the vacancy of high bauxite shortage is filled, and the medium-low grade bauxite is reasonably utilized; and during preparation, the rotating speed of a mixer in preparation is controlled to help form a semi-finished blank ball with high sphericity, so that the ceramsite sand with excellent mechanical property is prepared.

The invention relates to a method for laser pulse sputtering deposition preparation of a polycrystalline silicon thin film, wherein the method includes the following steps: pre-treating a base plate; putting a film plating material silicon target and the base plate into a vacuum system, vacuumizing to 1.0*10<-4> Pa, wherein the base plate temperature is 500-700 DEG C, and the distance between the base plate and the silicon target is 3-8 cm; then taking an excimer laser as a laser source, emitting laser, and with the frequency of 2-5 HZ, sputtering for 2-4 h; and finally annealing for 2-4 h at the temperature of 600-1000 DEG C, and thus obtaining the polycrystalline silicon thin film, wherein the base plate is a copper sheet or quartz glass. The prepared polycrystalline silicon thin film has fine grains and uniform size distribution, has quite good smoothness and compactness, has a better crystallization degree, moreover, has hardly any impurity atoms, can produce fine grains on various base plates, and is simple in process, good in repeatability, low in cost and suitable for industrialized production.

The invention provides a low-temperature polycrystalline silicon thin film transistor array substrate and a manufacturing method thereof. A gate insulation layer whose thickness is the odd number times a 1 / 4 laser wavelength on a patterned amorphous silicon to serve as an insulation layer. As the thickness of the gate insulation layer is the odd number times the 1 / 4 laser wavelength, the laser can pass through the gate insulation layer to the maximum degree to reach the patterned amorphous silicon, good crystallization processing is carried out on the patterned amorphous silicon, and large crystal grains are acquired. As the surface of the gate insulation layer is uniform, the passing laser thus uniformly irradiates on the patterned amorphous silicon, and the polycrystalline silicon with uniform crystal grains is thus formed.