43results about How to "Overcoming the problem of low yield" patented technology

The invention relates to a method for preparing nano hydroxyapatite powder, belonging to the field of the biomedical material. The method for preparing the nano hydroxyapatite powder comprises the following steps: adding the organic polymer of polyethylene glycol to the initial reactants of calcium nitrate and diammonium phosphate solution to adjust and control the morphologies of the products of reaction; adding aqueous ammonia to adjust the pH values of the products of reaction, and making the aqueous ammonia react with the products of reaction at different water bath temperature to synthesize nano hydroxyapatite precipitate, wherein the agglomeration of the synthesized nano hydroxyapatite precipitate can be inhibited by the polyethylene glycol functioning as the dispersant; freezing and drying synthesized nano hydroxyapatite precipitate slurry to obtain dry nano hydroxyapatite powder which contains by-products of reaction and polyethylene glycol, and calcinating the dry nano hydroxyapatite powder at high temperature to remove the by-products of reaction and the polyethylene glycol which are contained in the dry nano hydroxyapatite powder to obtain the nano hydroxyapatite powder which is in the shape of the ball or the rod and in the particle size of 10-100 nm and has high yield and good dispersion. The method for preparing the nano hydroxyapatite powder is simple, needs short preparing period, causes no poison and pollution and is suitable for industrial production.

The invention relates to a grain material optical color selector which comprises a discharge chute, an image collecting system, a blowing system as well as an information treating control system. The observing area of the image collecting system is arranged on a material moving track limited by the discharge chute; the information treating control system is respectively connected with the image collecting system and the blowing system in a signaling way used for identifying the grains with different colors according the image digital signals of the image collecting system and controlling the blowing system to carry out corresponding blowing actions. The blowing system is provided with a plurality of blowing nozzles; the blowing path of each blowing nozzle passes through the material moving track limited by the discharge chute; the crossing position of the blowing paths and the material moving track is arranged below the observing area of the image collecting system. The image collecting system preferentially selects a CCD camera of area array CCD imaging or linear array CCD imaging. The color selector has large treating amount, simple structure and accurate judgment to the grains with different colors, which can automatically remove the grains with different colors in the material and is mainly used for sorting the grain materials, such as rice, etc.

The invention discloses R-1-(3-methylphenyl)ethanol and a synthetic method of an ester thereof. The preparation method of R-1-(3-methylphenyl)ethanol comprises the following steps: taking 1-(3-methylphenyl)ethanol as a raw material, lipase as a biologic resolution catalyst, acidic resin as a racemization catalyst, and p-chlorophenol ester as an acyl donor, conducting dynamic kinetic resolution to obtain R-1-(3-methylphenyl)ethanol ester, and then conducting LiOH hydrolysis to obtain R-1-(3-methylphenyl)ethanol. The R-1-(3-methylphenyl)ethanol and the synthetic method of the ester thereof disclosed by the invention have the advantages of mild conditions, environment friendliness, good product yield, high selectivity and cheap price and good feasibility of the adopted racemization catalyst, so that the technology has a high application value in industrial production.

The invention provides a method for separating and purifying phytase with simpleness and high efficiency. The method comprises the following steps of: centrifugating fermentation liquor producing the phytase by a centrifuge, collecting supernatant, utilizing substrate applied by the phytase, namely phytic acid (or phytate), as affinity chromatography adsorbent, directly adding the phytic acid (or phytate) into the supernatant, stirring fully and evenly, and absorbing phytic acid (or phytate) and the phytase with specificity. Due to strong sequestering power, the phytic acid (or phytate) generally forms insoluble salts with minerals of calcium, magnesium, sodium, zinc, iron, copper, manganese and the like. At the moment, the adding of inorganic salt containing the metal ions can precipitate the combined body of phytic acid and phytase, and the precipitates can be collected by the centrifuge and is dried by a drier so as to obtain the preparation of phytase powder. The method has the advantages of simple and convenient separation and purification, high yield, high purity, low cost and the like.

The invention discloses a preparation method of an isotropic graphite material. The preparation method specifically comprises the following steps: doping mesocarbon microbeads with different particlesizes with chopped carbon fibers, carrying out liquid-phase oxidation treatment, carrying out compression molding by a secondary cold isostatic pressing method, and carrying out carbonization and graphitization. According to the invention, the problem of low yield caused by product cracking in the existing ink preparation technology taking the mesocarbon microbeads as a raw material is effectivelysolved, the bending strength of the graphite material is also improved, the compactness is improved, and the resistivity and the aperture ratio are reduced, so that the performance of the graphite material is improved.

The invention relates to a method for producing D-plant nucleic acid by using Bacillus subtilis to ferment which includes the steps: (1) inoculating the production strain of transketolase defect Bacillus subtilis into a seed culture medium to activate to obtain a seed liquid; (2) preparing a fermentation culture medium which takes dextrose as a carbon source and adding organic acid such as citric acid or lactic acid; (3) inoculating the seed liquid into the fermentation culture medium to carry out fermentation. The method of the invention has the beneficial effects of: being capable of remarkably increasing the yield of the D-plant nucleic acid and improving the yield rate; reducing the outgrowths in the fermentation liquid, thus being beneficial to the separation and extraction of the D-plant nucleic acid; being simple and practical to control the fermentation metabolic process and being easily industrialized.

The invention discloses a wavelength selective radiator coating applied to a thermophotovoltaic power generation device and a preparation method of the wavelength selective radiator coating. Firstly, erbium oxide powder and aluminum oxide powder are uniformly mixed, then mixed powder is obtained, grinding balls, a ball-milling liquid, the mixed powder and a dispersing agent are added to a ball-milling tank for ball milling, and uniformly dispersed slurry is obtained; the grinding balls in the slurry are filtered out, the ball-milling liquid in the slurry is dried, and dry powder is obtained; the dry powder is put in a high-temperature atmosphere furnace and heated, so that the erbium oxide powder and the aluminum oxide powder in the dry powder are sintered to form composite powder, the grinding balls, a binding agent and a diluent are added to the composite powder, the mixture is subjected to ball milling, the uniformly mixed slurry after ball-milling is dried, and then a die can be used for coating a substrate material; after the coated substrate material is dried and sintered at a high temperature, the wavelength selective radiator coating is formed and obtained. The mechanical performance and the surface strength of the coating are improved, the thermal stability of a coating radiator is improved, and the defect that the coating cannot be bonded to a ceramic substrate easily is overcome.

The invention relates to a catalytic synthesis method of an organic chemical intermediate 1,2-diketone compound. Asymmetric aryl alkyl acetylene is taken as a raw material, direct catalytic oxidation reaction is achieved in the presence of a multi-component catalyst/assistant system, so as to prepare the 1,2-diketone compound. Effects of types of components of the catalyst and the assistant are researched by a lot of experiments, and a reaction solvent applicable to the system is properly screened. The synthesis process is high in reaction yield, mild in reaction condition and short in reaction time, is an excellent synthesis method of the 1,2-diketone compound, and has broad large-scale industrial application value and market potential.

The invention discloses a preparation method of calcium astragalus polysaccharide. The preparation method comprises the following steps: (1) extracting radix astragali with ethanol of which the concentration is 5 wt% and the pH is 9; carrying out filtering to obtain a filtrate; concentrating the filtrate till ethanol is removed completely; drying to obtain an astragalus polysaccharide extract; (2) dissolving the astragalus polysaccharide extract obtained in the step (1) with water, adding a calcium chloride solution to adjust the pH to be 9 to 11, and carrying out a reaction for 6 to 48 hours at 60 to 90 DEG C; (3) purifying the reaction liquid obtained in the step (2) to obtain calcium astragalus polysaccharide. The preparation method has the advantage that the yield of calcium astragalus polysaccharide can be improved obviously, thereby being suitable for industrial application.

The invention relates to the field of organic synthesis, and discloses a method for preparing m-diisopropylbenzene hydrogen peroxide and p-diisopropylbenzene hydrogen peroxide, which comprises the following steps: contacting a material containing m-di (2-hydroxy isopropyl) benzene and p-di (2-hydroxy isopropyl) benzene with hydrogen peroxide to react; obtaining a reaction mixture containing m-diisopropylbenzene hydroperoxide and p-diisopropylbenzene hydroperoxide; and carrying out solid-liquid separation on the reaction mixture to obtain a liquid phase containing m-diisopropylbenzene hydroperoxide and a solid phase containing p-diisopropylbenzene hydroperoxide. The m-diisopropylbenzene hydrogen peroxide prepared by the method provided by the invention has the purity of 95% or more and the yield of 82% or more, the p-diisopropylbenzene hydrogen peroxide has the purity of 97% or more and the yield of 86% or more, and the method has the advantages of less waste acid generation amount, cleanness, environmental protection, mild reaction conditions and easy control of reaction, and is suitable for industrialization.

The invention discloses a synthesis method of o-tert-butyl aniline. The reaction formula is shown in the specification, wherein R1 and R2 are independently selected from CH3 or H; the preparation method comprises the following steps: carrying out a heating reaction on a compound shown in a formula III and alkali in an organic solvent to obtain an o-tert-butyl aniline compound, wherein the molar ratio of the compound shown in the formula III to the alkali is 1: (3.5-7.5). The synthesis method provided by the invention overcomes the problem of low yield of aryloxy amide of which the ortho-position is a tert-butyl electron-donating group in the prior art, the yield reaches 70% or above, and the synthesis method is high in safety, low in cost, good in selectivity, high in yield and suitable for large-scale production.

The invention discloses R-1-(2,5-dimethylphenyl)ethanol and a synthetic method of an ester thereof. The preparation method of R-1-(2,5-dimethylphenyl)ethanol comprises the following steps: taking 1-(2,5-dimethylphenyl)ethanol as a raw material, lipase as a biologic resolution catalyst, acidic resin as a racemization catalyst, and p-chlorophenol ester as an acyl donor, conducting dynamic kinetic resolution to obtain R-1-(2,5-dimethylphenyl)ethanol ester, and then conducting LiOH hydrolysis to obtain R-1-(2,5-dimethylphenyl)ethanol. The R-1-(2,5-dimethylphenyl)ethanol and the synthetic method of the ester thereof disclosed by the invention have the advantages of mild conditions, environment friendliness, good product yield, high selectivity and cheap price and high feasibility of the adopted racemization catalyst, so that the technology has a high application value in industrial production.

The invention discloses a double concave diamond energy transmission window and a preparation process thereof, which solve the problem that the effective welding area of a window sheet of an energy transmission window in the prior art is smaller and smaller, thus leading to difficulty of metallization of a box type window. The window includes a first rectangular waveguide, a first circular waveguide, a diamond window sheet, a second circular waveguide, and a second rectangular waveguide that are sequentially connected, and a surface of the diamond window sheet orienting to the first circular waveguide or/and the second circular waveguide is disposed as an inwardly-concave cambered surface. The window achieves the effect of effectively increasing the metallized area without substantially changing the size of the box type window.

The invention provides a clean synthesis method of an iron oxide red pigment with low oil absorption. The method comprises the following steps: 1, preparation: adding 30-50 parts of FeSO4.7H2O into an auxiliary agent, and dissolving to prepare a solution A; 2, primary crystallization: mixing the solution A obtained in the step 1 with a NaOH solution B, and then precipitating and uniformly oxidizing to prepare gamma-FeOOH primary seed crystal; 3, secondary crystallization: adding the gamma-FeOOH primary seed crystal suspension prepared in the step 2 into the solution A in the step 1, stirring and oxidizing, and adding a NaOH solution B to prepare gamma-FeOOH secondary seed crystal; 4, tertiary crystallization: adding the gamma-FeOOH secondary seed crystal obtained in the step 3 into the solution A obtained in the step 1, adding a NaOH solution B at the same time, and stirring and oxidizing to obtain gamma-FeOOH tertiary seed crystal; and 5, preparation of a finished product of iron oxide red: preparing a FeSO4.7H2O solution, heating the gamma-FeOOH tertiary seed crystal suspension obtained in the step 4, then adding the FeSO4.7H2O solution, heating, and carrying out suction filtration, washing, drying and grinding to obtain the finished product of iron oxide red.