258results about How to "Control growth rate" patented technology

A first set of orange LEDs with a peak wavelength emission of about 612 nanometers, a second set of red light emitting LEDs with a peak wavelength of about 660 nanometers, and blue light LEDs. Two beam spreads, 15° and 30°, were provided for both the 660 nm LEDs and 612 nm LEDs. When directed perpendicularly upon tops of the plant leaves, 10% light transmission occurred through the leaves for the 30° LEDs, and 80% light transmission for the 15° LEDs. Thus, fully 50% of the orange / red spectrum primarily used for photosynthesis was transmitted through the upper leaf canopy, making it available to support photosynthesis in leaves below. LED lamps are positioned at varying distances from the growing plants for controlling plant growth rates that vary with these distances, thereby to control plant inventory, because growth of plants can be greatly slowed to preserve them during periods of slow sales.

A multifunction plant cultivation LED able to control the growing speed of plants is to properly select the composition material and proportion of LED to enable the LED to emit light with different wavelengths and colors. Then, specific wavelengths beneficial to the growth of plants and able to offer best bright for human naked eyes are selected from light spectrums to make up a LED light source with multiple wavelengths for irradiating landscaping plants and flowers and controlling their growing speed as well as for seeing, enjoying and for lighting, versatile in use, having high efficiency and saving electricity.

The invention provides a method for preparing a hydrogenation catalyst with high activation. A disposition method is adopted to carry out step-by-step loading to the active components of the metals of VIB and VIII families; the VIB metal comprises tungsten or molybdenum, while the VIII metal comprises nickel or cobalt; a carrier is alumina. The loading of VIB metal takes a corresponding soluble salt as raw material, an acid solution as a precipitator and a cationic surface active agent as a dispersant. In a hydrothermal condition, the corresponding soluble salt, the acid solution and the cationic surface active agent produce metallic oxide particles by a liquid deposition reaction; the loading of VIII metal also takes a corresponding soluble salt as raw material and carbamide as a precipitator; the adding of the precipitator and the generation of precipitation are separated by controlling reaction temperature in sections and even precipitation is realized to disperse the particles of the active components on the carrier evenly. The hydrogenation catalyst prepared shows good effects in the respects of desulfurization and denitrification activation and can greatly reduce the usage of the active components.

The invention relates to a porous material and a preparation method thereof, in particular to a technology in which silk fibroin is taken as a raw material to prepare porous three-dimensional materials. In the method, silk fibroin solution is injected into a metal mould, 1-24 hours of quick freezing is carried out on the solution at the low temperature of minus 10-minus 80 DEG C, thus obtaining afrozen body; the frozen body is preserved at the temperature of minus 5-minus 25 DEG C for 2-60 days, thus obtaining frozen crystalline solid; then the frozen crystalline solid is thawed and dried, thus obtaining the silk fibroin porous three-dimensional material. The silk fibroin of the porous material is fibroin I type crystal structure, therefore, the silk fibroin is insoluble in water and canbe completely degraded in a while and is finally degraded into nonpoisonous amino acid; the material of the invention has mutual run-through pores with aperture of 10-500 microns; the pores and pore diameter are relatively large, thus being suitable for growth of cells; meanwhile, in the process of preparation, no chemical cross linking agent, foaming agent or denaturing agent are needed, thus retaining fine biocompatibility of the silk fibroin.

The invention relates to a process for preparing ultra-fine metal powder and in particular relates to the process for preparing nanometer-grade ultra-fine copper powder. The process which is provided by the invention for preparing the ultra-fine copper powder comprises firstly, using reducing agent solution whose amount is 1-2 times of theoretical amount which is needed to reduce divalent copper compounds to one valence copper compounds to enable solution of the divalent copper compounds to carry out the first reducing reaction, preparing solution which contains the one valence copper compounds, then, using the reducing agent solution whose amount is 1-2 times of the theoretical amount which is needed to reduce the one valence copper compounds to pure copper to enable the solution which contains the one valence copper compounds to carry out the second reducing reaction, and preparing ultra-fine copper powder. According to the process for preparing the ultra-fine copper powder, reaction speed for reducing copper ions into pure copper can be increased greatly, growing speed of nucleations and crystal nucleus of copper powder can be controlled better, and thereby finer, stable, and even nanometer-grade ultra-fine copper powder with narrow distribution of particle diameters can be obtained.

The invention discloses a ternary precursor with a controllable crystal structure, a positive electrode material and a preparation method of the positive electrode material. Specifically, a nickel-cobalt-manganese soluble salt, NaOH, concentrated ammonia water and a surfactant for oriented growth are separately formulated into solutions and then subjected to a coprecipitation reaction to obtain aternary precursor of an oriented grow structure; the precursor is mixed with a lithium source and then calcined at high temperature to obtain a ternary layered positive electrode material of an oriented grow precursor-like structure. The positive electrode material the crystal structure of which grows in a [003] direction is obtained by regulating the growth of the precursor, so that the order degree of internal structure growth is increased, the stability of internal structure growth is improved, cation mixing and Li+ diffusion resistance are reduced, and the Li+ diffusion coefficient is increased. The ternary precursor with the crystal structure controllable, the positive electrode material and the preparation method of the positive electrode material are applicable to lithium-ion powerbatteries. Compared with existing products, the ternary precursor and the positive electrode material have the advantages that the rate performance and cycle stability of lithium-ion batteries are significantly improved.

The invention discloses a method for preparing a uniform transparent zinc oxide nano-rod array membrane by pulse electrodeposition, belonging to the preparation field of nano materials. The method comprises in turn the following steps: analytically pure zinc chloride and potassium chloride are dissolved in distilled water, and are stirred so as to obtain stable transparent solution; the the solution is fed into water bath with the temperature of between 60 and 80 DEG C so as to maintain a constant temperature, and oxygen is continuously fed into the solution; and in a three-electrode system, ITO conductive glass coated with a ZnO nano particle membrane is used as a cathode, while a platinum sheet is used as a counter electrode and a saturated calomel electrode is used as a reference electrode so as to carry out pulse electrodeposition to prepare a ZnO nano-rod array membrane under applied voltage of between 0.8 V below zero and 1.1V below zero with the on-off time ratio ton / toff controlled between 10s / 10s and 1s / 1s. Through adjusting the initial concentration of precursor and controlling factors such as the applied voltage of pulse electrodeposition, on-off time ratio of voltage and pulse frequency, the method prepares the transparent zinc oxide nano-rod array membrane with the diameter less than 50nm and uniform and controllable length, and effectively increases the quality of the membrane. The method has the advantages of simple process, strong controllability and less energy consumption, and can meet the requirements of mass production; moreover, the method has an enormous application prospect in the fields of solar battery, photoelectron, catalysis, and the like.

Through carbonization in Ca(OH)2 suspension by leading-in kiln gas containing CO2; controlling the nucleation rate of calcium carbonate crystal nucleus by the temperature of Ca(OH)2 suspension and the CO2 flow rate; controlling the growth rate of crystal faces by adding crystal form regulator; adding dispersant to regulate surface charge; and liquid phase surface coating dispersed cubic nanometercalcium carbonate grains, transparent nanometer calcium carbonate material for ink is prepared, which has size of 15-40 nm, GSD of 1.57, specific surface area greater than 35 sq m / g, ink oil absorption of 0.4 g / g and no coagulation. The calcium carbonate material may be used to produce transparent ink for high grade lithography.

The invention discloses high specific surface area silver powder improving conductivity of a solar battery electrode and a preparation method. The silver powder has an average particle size of 0.6-0.75 micrometers, an apparent density of 2.5-5.0g / mL, a tap density of 4.15-6.95g / mL and specific surface area of 0.45-0.75m<2> / g. The method comprises the steps of preparing a silver nitrate solution and a reducer solution, adding a dispersing agent, performing parallel flow addition of various reaction system solutions into a reaction vessel by twice in a twice addition manner, uniformly mixing the reaction system solutions for the first time, keeping a PH value and temperature of reaction liquid as 2-5 and 25-60 DEG C, continuing stirring for 10-30min after feeding, and adding a mixed reaction solution in a parallel flow addition manner with the addition volume of 0.25-0.75 time of the total addition volume of the first time. The silver powder is a spheroid covered with bulges on the surface, is uniform in particle size and has a good crystal surface and high dispersity; the photoelectric conversion efficiency can be improved when the silver powder is used as front silver electrode slurry of crystalline silicon solar battery; the silver powder particularly has excellent characteristics in aspects of short-circuit current, contact resistance, fill factor and the like.

The invention discloses a method for preparing flaky nano copper powder, comprising the following steps: compounding a copper salt aqueous solution with a surfactant to obtain a mixed solution A, wherein the water in the copper salt aqueous solution and the surfactant form a surfactant compound system; (2) compounding a reducing agent aqueous solution with the surfactant which is the same as that used in step (1) to obtain a mixed solution B, wherein the water in the reducing agent aqueous solution and the surfactant form the surfactant compound system; (3) mixing the mixed solution B obtained in step (2) and the mixed solution A obtained in step (1) by stirring at the temperature of 20 DEG C to 80 DEG C, and reacting completely with stirring; and (4) carrying out solid and liquid separation on the product, washing the solid, and carrying out vacuum drying to obtain the flaky nano copper powder. The method of the invention has mild condition, simple process, short production period, low equipment investment and low preparation cost, and is easy to realize industrial production. The prepared flaky nano copper powder has consistent appearance, uniform size and good dispersibility.

The invention discloses a transparent super-hydrophobic nano-array and a preparation method thereof. The preparation method comprises the following steps: firstly coating the surface of a substrate with zinc oxide seed crystal sol by virtue of a spin coating method or a spray coating method, so as to obtain a uniform nano-seed crystal layer; then controlling the hanging altitude and the position in a low-concentration growth solution prepared from KOH and Zn(NO3)2 by virtue of a vertical cotton thread hanging technique, so as to obtain a transparent zinc oxide nano-array, and carrying out fluorination to construct excellent super-hydrophobicity; and carrying out double-surface coating, sintering and growth on the substrate, so as to obtain the transparent super-hydrophobic nano-array on two surfaces of the substrate. Liquid drops with condensed and frosted surfaces are of a sphere shape, small in sizes, extremely easy to combine and bounce, high in desorption rate and low in coverage rate, present excellent frosting resistance and have important application prospects in products of building exterior glass, solar cells, automotive glass and the like, and furthermore, concepts can be provided for application of dropwise condensation, frosting resisting, freezing resisting and the like.

The invention relates to the process for purifying purifying phosphoric acid through crystallization process, which comprises pre-processing the raw material acid, precleaning with solvent precipitation method, concentrating the obtained phosphoric acid to 85-90% and carrying out crystallization operation at 8-20 deg. C, introducing seed crystal 1-3 wt% of the total acid liquor quality, disintegrating, scouring and diluting the crystal, fluxing the obtained crystal, diluting to 85-90% and carrying out recrystallization, third crystallization, finally separating, washing and diluting the crystal product.

The invention discloses a high-density fermentation method of engineering bacteria containing nitrilase. The method adopts a novel recombinant Escherichia coli fermentation and supplementary material culture medium formula, and uses a method of DO-STAT coupling step-by-step induction and gradual increase of the speed stage by stage. The method not only meets the need for mixing power in the culture process with biomass increase, effectively controls the growth rate of thalli, and prevents disadvantages of produced acid accumulation caused by fast growth of thalli, feedback inhibition and culture medium waste. In addition, the induced mode of batch-by-batch lactose supplement addition avoids the high viscosity of the fermentation broth caused by high concentration of lactose, resulting in resistance of oxygen transfer and mass transfer, but also improves the induction strength. The high-density fermentation technology of the invention increase the biomass of recombinant Escherichia coli from 10.35g DCW / L to 70g DCW / L, volume enzyme activity from 18205U / L to 103530U / L, and the fermentation level by 4.7 times.

The invention relates to the field of artificial crystal growth, in particular to a method and a device for growing a novel KDP-type crystal, i.e. a method for growing the crystal by circularly evaporating a solution. The device consists of a container and a temperature control system. The container part comprises a heat insulating trough and a growth cylinder, wherein the heat insulating troughis partitioned into an upper part and a lower part which by a partition board in the middle. The lower part is filled with distilled water, is used for water bath and heat insulation and is a high-temperature region, and the upper part is heat-insulated by using the air bath and is a low temperature region. The growth cylinder is also divided into two parts; the upper lid part is a dissolving chamber while the lower part is a growth chamber. The growth chamber is in the water bath of the heat insulating layer. The dissolving chamber is in the air bath of the heat insulating layer. The growthdevice can be used for the growth of crystals of potassium dihydrogen phosphate, potassium dideuterium phosphate, ammonium dihydrogen phosphate and ammonium dideuterium phosphate as well as the same series of KDP-type crystals. The crystal with bigger size can be grown in a relatively small growth cylinder by using the growth device. The invention has the advantages of high growth speed, high crystal quality, simple growth equipment, reduced investment cost and improved economic benefits.

The invention discoses a prepartion method of highly anti-yellow resistance white carbon black for silastic, processing steps include dissolution and refining of solid soluble glass, precipitation reaction of the soluble glass and concentrated sulfuric acid under function of organic surface active agent, after synthetic reaction, homemade composite anti-yellow agent B is used to proceed anti-yellow treatment to surface of silicon dioxide particles, then through filter pressing, washing, liquefaction of filter cake, spray drying and semi-finished product collecting, crushing and grading, and products collecting to obtain highly anti-yellow resistance white carbon black for silastic. White carbon black produced according to the method has advantages of stable and reliable quality, excellent anti-yellow performance, which solves crucial problem of easily yellowing in white carbon black in precipitation method for silastic.

The invention provides a preparation method of a nickel-cobalt-manganese ternary material; under the stirring effect, the co-precipitation reaction is implemented for soluble salt of nickel, soluble salt of cobalt, soluble salt of manganese and precipitating agent under the condition of 7.5-8.5 of pH value to obtain a nickel-cobalt-manganese ternary material precursor; the stirring speed is 600-1000 r / m; the reaction temperature of the co-precipitation reaction is 40-60 DEG C; the lithiation is implemented for the nickel-cobalt-manganese ternary material precursor to obtain the nickel-cobalt-manganese ternary material. The preparation method prepares the nickel-cobalt-manganese ternary material precursor with spherical morphology through comprehensively controlling the stirring speed and reaction temperature of the co-precipitation reaction and the pH value of the reaction system in the reaction process in the process of preparing the nickel-cobalt-manganese ternary material precursor; the method for preparing the nickel-cobalt-manganese ternary material, provided by the invention, is environment-friendly, and has lower cost.

The invention provides a method for preparing rare earth oxides, which comprises: mixing solution of rare earth salts and polyvinylpyrrolidone, and dissolving the mixture in an organic solvent to obtain first reaction solution, wherein the solution of the rare earth salts is solution of rare earth nitrates and / or rare earth chlorides and the solution of the rare earth salts may contain one or two of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutecium and yttrium; dissolving thiourea in an organic solvent to obtain second reaction solution; mixing the first reaction solution and the second reaction solution, heating the mixed reaction solution, and allowing the mixed solution to react at a constant temperature to obtain a precursor; and calcining the precursor in sulfur-containing atmosphere to obtain spherical rare earth oxides. The rare earth oxides prepared by the method have a spherical shape, and therefore, materials prepared by using the rare earth oxides have remarkable luminous effect.

The invention discloses a chemically strengthenable self-crystallizing glass ceramic and a preparation method thereof. The glass ceramic has crystals with the average crystal size ranging from 5 nm to60 nm, a main crystal phase of the crystals is at least one of a beta quartz solid solution, nepheline and a nepheline solid solution, the crystals account for 30%-90% by mass of the glass ceramic, and the glass ceramic contains 8%-13% of Li2O by mole, the content ratio of Al2O3 to Li2O is greater than or equal to 1.8, the sum of the content of the Li2O and the content of the Na2O is 10% to 15%,and nucleating agents ZrO2, TiO2 and fluoride are not added in the glass ceramic. The glass ceramic has the advantages of high aluminum content, high lithium content and low sodium content in composition, and contains no nucleating agent; the high lithium content increases the crystallization tendency of the glass substrate to realize uniform crystallization; the crystal growth speed can be controlled by the high aluminum content, so that the glass ceramic network structure is firm, and the mechanical strength is improved; the low nano content can reduce the dielectric constant of the glass ceramic.

The invention discloses a method for preparing subsphaeroidal barium sulfate by a sulfuric acid process, which aims to solve the problems that barium sulfate particles have unshaped morphology and wide particle size distribution. The method comprises the following concrete steps that: (a) coal is used to calcine barite to generate barium sulfate; (b) water is used to dissolve the barium sulfate to be prepared into 70 to 130g / L barium sulfate solution, the temperature is adjusted to be between 45 and 85 DEG C, the barium sulfate solution and excessive sulfuric acid are synchronously added into a continuous reactor to react to generate barium sulfate slurry and hydrogen sulfide, and the adding rate of the barium sulfate solution is between 500 and 7,000L / h; (c) hot air is introduced into the barium sulfate slurry to discharge the hydrogen sulfide; and (d) the barium sulfate slurry is dehydrated, washed, dried and crushed to obtain a finished product of the subsphaeroidal barium sulfate. The barium sulfate which is spheroidal or subsphaeroidal and has continuously adjusted particle size distribution can be obtained by the preparation method. At the same time, the invention also discloses application of the subsphaeroidal barium sulfate used as a packing material to copper foil substrates.

The invention discloses a preparation method of a high-activity molybdenum disulfide (MoS2) hydrogenation catalyst. The method comprises the following steps: dissolving or dispersing a certain amountof molybdenum source and reductive sulfur source in a high-viscosity solution, and adding a reducing agent to obtain a solution or turbid liquid; regulating and controlling the types of the molybdenumsource, the sulfur source and a solvent; putting the prepared solution or turbid liquid into a closed stainless steel reaction kettle, and controlling the reaction temperature to be 120-220 DEG C andthe reaction time to be 3-72 hours; and after the reaction is finished, cooling, separating, washing and drying to obtain the high-activity MoS2 hydrogenation catalyst. The synthesis method disclosedby the invention has the advantages of low temperature, low pressure, no need of adding an additional reducing agent and the like, and the prepared MoS2 hydrogenation catalyst has the advantages thatthe interlayer spacing is enlarged, the accumulation degree is less than 3 layers, and the lamellar length is shorter than 10nm, so that the highest hydrogenation active site exposure rate is achieved. The high-activity exposed nano MoS2 hydrogenation catalyst synthesized by the method disclosed by the invention has extremely high catalytic hydrogenation activity in the field of catalytic hydrogenation of oil products.

The invention discloses an epoxy-resin-based high-dielectric composite material and a preparation method thereof. According to the composite material, epoxy resin serves as a base body, modified barium titanate serves as filler, and the modified barium titanate is modified barium titanate BTNC doped with niobium pentoxide and cobaltosic oxide. The modified barium titanate BTNC is fully mixed with epoxy resin and a curing agent, heating and curing are conducted, and the BTNC / epoxy resin dielectric composite material is obtained. Compared with an epoxy resin composite material filled with barium titanate which is not modified, the composite material has a higher dielectric constant, lower dielectric consumption and better temperature stability.

The invention discloses a method for preparing spherical silver powder by a fractional step method. Reducing liquid, silver ammonium solution, a PH adjusting agent and a dispersing agent are respectively added in multiple serially connected reaction devices in sequence in a jet manner, and are fully mixed in sequence in different reaction containers for fraction step reaction. (1) a nanosilver seed crystal is generated by controlling a reducing reaction; (2) the nanosilver seed crystal is selectively grown by controlling reducing reaction conditions; (3) the damage of sphericity of silver powder due to quicker growth speed is prevented by controlling the reducing reaction conditions; and (4) micron-grade spherical silver powder with uniformly distributed particle sizes is quickly grown by controlling the reducing reaction conditions. Finally, the generated high-dispersibility spherical silver particles and the remained liquid are conveyed into a separation system; silver particles are separated from the remained liquid by a centrifugation or floculation precipitation effect to obtain the high-dispersibility spherical silver particles; the spherical silver particles are cleaned by de-ionized water or ethanol for drying to obtain the spherical silver powder. The method is simple and stable in production process, and is higher in quality of the spherical silver powder.

The invention relates to a method for preparing a REBa2Cu3Ox (REBCO) high-temperature superconducting block material, in particular to a melt texture growth (MTG) method for the REBCO high-temperature superconducting block material. The MTG method for the REBCO high-temperature superconducting block material comprises the following steps of: a) mixing raw materials; b) grinding and calcining to obtain a superconducting material rough blank; c) tabletting; d) firing; and e) cooling to obtain the REBCO high-temperature superconducting block material, namely e1) cooling to buffer temperature, and preserving heat, e2) cooling to growth temperature, and preserving heat, and e3) quenching. By the method, the technical problem that the REBCO high-temperature superconducting block material fails to grow because spontaneous nucleation is generated when temperature is reduced from the maximum temperature to the growth temperature in the conventional MTG method is solved.

The invention discloses a method for the bickiron inoculation of buds symbiotic to root fungi for culturing the seedlings of Chinese chestnut. The method adopts the methods of the bickiron graft of bud seedlings and the root-pruning inoculation of root fungi for breeding the container seedlings of Chinese chestnut of which the root system is symbiotic to the root fungi, prior diluted Chinese chestnut mycorhiza liquid or a prior Chinese chestnut mycorhiza agent is adopted, and inoculation is carried out after root pruning; on one hand, side roots have flourishing growth; on the other hand, the root system is symbiotic to the root fungi, and then the container seedlings are transplanted into a greenhouse for large-scale culture; and the seedlings after being cultured successfully are directly transplanted into a plowland, the seedling raising time is quick, the survival rate of the seedlings is high, and the growth of the seedlings is robust.

The invention provides a production method of glucose oxidase, and the production method comprises the following steps: (1) taking aspergillus niger seed to inoculate into a first stage seed culture medium for culturing to obtain a first stage seed solution; (2) inoculating the first stage seed solution into a second stage seed culture medium for culturing to obtain a second stage seed solution; (3) inoculating the second stage seed solution into a fermentation culture medium to obtain a mixed culture medium, then adding fructose, feeding in batch glucose to obtain a fermented liquid with the enzyme activity reached above 200U / mL; (4) filtering the fermented liquid, concentrating a filter liquid by ultrafiltration to obtain a glucose oxidase enzyme solution with the enzyme activity reached above 800U / mL; (5) using starch as a carrier to perform spray drying of the glucose oxidase enzyme solution to obtain the solid glucose oxidase with the enzyme activity reached above 2500U / mL. The production method of the glucose oxidase has the advantages of simple process, easy operation and high production efficiency, and the produced glucose oxidase has a high activity and good stability, and is easy to store.

The invention discloses a powder catalyst for synthesizing ultrafine granular diamond. The powder catalyst is mainly prepared from the following alloying components by weight percent: 20% to 25% of Fe, 3% to 5% of Co, 0.5% to 2% of Ce, 3% to 5% of Mn, 0.5% to 1% of SiC, 0.5% to 1% of Mo and the balance being Ni. By utilizing the technical scheme of the powder catalyst, the high-purity ultrafine-particle spherical or approximately spherical powder catalyst can be prepared, and the granularity of the obtained powder catalyst is 600 to 1000 meshes. When the powder catalyst is applied to synthesis of ultrafine diamond single crystal, single-crystal diamonds within 400 meshes can be produced.

The invention discloses a method for preparing nano copper powder in a micromolecular viscous medium. The method comprises the steps of: by taking a surface active agent, salt, a complexing agent, an antifoaming agent, an antioxidant, cupric salt, a reducing agent and deionized water as raw materials and according to the proportion of (0.001-95 percent) : (0.001-95 percent) : (0.001-80 percent): (0.001-75 percent): (0.001-70 percent): (0.001-75 percent): (0.001-70 percent): (0.001-98 percent), preparing the micromolecular viscous medium by using the surface active agent, the salt, the complexing agent, the antifoaming agent, the antioxidant and the deionized water; adding the cupric salt and uniformly mixing; adding the reducing agent and mixing; adding the deionized water to dilute so asto reduce the degree of viscosity according to a mass ratio of 1:0.5-10 of the total quantity of all materials abovementioned to the deionized water after the reaction completes; and obtaining nano copper powder through filter-pressing, deionized water washing, acetone washing and vacuum drying. According to the method disclosed by the invention, the raw materials selected in the invention are easily available, the manufacturing technique is simple and short, the production efficiency is high, the production cost and the energy compunction are low, and powder has low possibility of agglomeration and has good dispersibility, therefore the method is suitable for large-scale production and solves the problems of easy oxidation and easy agglomeration of the nano copper powder existing in the traditional chemical preparation method.

The invention relates to a purifying method of a novel antibiotic compound. The method includes: (1) a step of salifying, namely a step of adding cefazedone and sodium isooctoate into absolute methanol and performing a salifying reaction until the cefazedone is fully dissolved, with the temperature being controlled at 15-35 DEG C; (2) a step of decoloring, namely a step of adding active carbon into the reaction solution, stirring, decoloring, filtering to remove the active carbon, maintaining the temperature of the filtrate at 10-30 DEG C, and filtering again; (3) a step of crystallizing, namely a step of adding a certain amount of acetone and ethyl acetate into the filtrate after the filtration, controlling the temperature at 15-20 DEG C, growing the grain for 1-2 h, then adding a certain amount of the acetone and the ethyl acetate, stirring for crystallization with the stirring speed being maintained at 80-120 r / min, controlling the temperature at 15-25 DEG C, and growing the grain for 2-4 h; and (4) a step of drying, namely a step of filtering, washing the filter cake, and drying to obtain a purified product of the cefazedone sodium. Compared with the prior art, the method has characteristics of simple operation, low cost, high yield, and largely reduced pollution. The purified product of the cefazedone sodium has characteristics of low water content, low purity content and high stability.

The invention discloses an epitaxial structure for improving the illumination efficiency of a high-power GaN-base LED (light emitting diode) and a growth method. The epitaxial structure sequentially comprises a substrate, a low-temperature GaN buffer layer, a GaN non-doping layer, an N type GaN layer, a multiple quantum well layer, a luminescent quantum well layer, a low-temperature P type GaN layer, a PAlGaN / PInGaN current blocking layer, a high-temperature P type GaN layer and a P type contact layer from bottom to top, wherein the growth of the PAlGaN / PInGaN electron blocking layer is completed through nine steps. An optimized PAlGaN / PInGaN structure layer is introduced between the epitaxial structure L-PGaN and H-PGaN, and a general electron blocking layer is replaced for further improving the electron leakage stopping effect. Through the structure, the performance of the InGaN / GaN base LED can be greatly improved in case of high-current-density injection.

The invention provides a preparation method of copper crystal whiskers, which comprises the following steps: 1, providing a copper base material, placing the copper base material in sulfur source solution to perform a vulcanization reaction so as to form sulfide of copper on the surface of the copper base material; 2, carrying out cleaning and drying processing on the copper base material of whichthe surface is provided with the sulfide of copper; 3, placing the copper base material of which the surface is provided with the sulfide of copper in reducing atmosphere to perform a reduction reaction so that the copper crystal whiskers grow and form on the surface of the copper base material. The preparation method provided by the invention is high in repeatability, simple and easy to operate,and suitable for scale batch preparation of the copper crystal whiskers. According to the invention, a growth speed and a size of the copper crystal whiskers can be controlled by controlling a degreeof the vulcanization reaction of the copper and a degree of the reduction reaction of the copper. According to the invention, by utilizing different copper base materials, growth of the crystal whiskers on a copper wire, a copper plate, copper powder and the like can be implemented, and performance of the base material is reinforced or expanded.