10867results about How to "High purity" patented technology

The invention belongs to the field of medical radioactive isotope preparation, and particularly relates to a method for extracting lead-212 and bismuth-212 from a thorium-232 decay chain, a solution containing a thorium-232 decay chain substance passes through an anion exchange resin column, the solution containing the thorium-232 decay chain substance contains halide ions, and the anion exchange resin column is used for extracting the lead-212 and the bismuth-212 from the thorium-232 decay chain substance. The concentration of hydrogen ions in the solution containing the thorium-232 decay chain substance is greater than 0.01 mol / L, the lead-212 and the bismuth-212 are adsorbed by the anion exchange resin column, other nuclides directly penetrate through the anion exchange resin column and are not adsorbed, a leaching reagent is introduced to desorb the lead-212 and the bismuth-212 from the anion exchange resin column, and the lead-212 and the bismuth-212 are separated and extracted; the method can be used for simultaneously extracting lead-212 and bismuth-212, has the advantages of high extraction speed and high purity, and is not easy to cause organic pollution to products.

The invention relates to plastic recovery equipment, and belongs to the technical field of plastic bottle recovery, the plastic recovery equipment comprises a first crushing cylinder and a second crushing cylinder, the middle parts of the first crushing cylinder and the second crushing cylinder are communicated with each other, and a feed hopper is fixedly communicated above the communication part of the first crushing cylinder and the second crushing cylinder; the lower portion of the communicating part of the first smashing cylinder and the second smashing cylinder is fixedly communicated with a separating cylinder, the lower side of the separating cylinder is communicated with a cleaning cylinder, smashing assemblies rotating oppositely are arranged on the inner side of the first smashing cylinder and the inner side of the second smashing cylinder correspondingly, and guide sleeves are fixedly arranged on the two sides of the upper portion of the inner side of the separating cylinder correspondingly; sliding plates are arranged on the sides, close to each other, of the two guide sleeves in a front-back sliding mode, a transmission mechanism for driving the two sliding plates to slide oppositely at the same time is arranged on the outer side of the separation barrel, and an air blowing mechanism is arranged on one side of the separation barrel.

The invention discloses a method for activating and precipitating MHP through magnesium, and belongs to the technical field of hydrometallurgy. The method comprises the following steps: S1, mixing a magnesium-containing solution with a sodium hydroxide solution, and carrying out precipitation reaction for 3-5 minutes to obtain a precipitator; s2, immediately mixing a precipitator with the laterite-nickel ore iron and aluminum removed liquid, and then carrying out first-stage nickel and cobalt precipitation reaction to obtain first-stage nickel and cobalt precipitation slurry; s3, performing first thickening treatment on the first-section nickel and cobalt deposited slurry to obtain first dense underflow and first dense overflow; and S4, filtering the first dense underflow to obtain an MHP product. According to the method, after the magnesium-containing solution and the sodium hydroxide solution are mixed, the magnesium solution and the sodium hydroxide solution are controlled to be mixed and react for 3-5 min, then the nickel and cobalt precipitation reaction is immediately carried out, the MHP product with high purity and quality can be obtained, and the whole method is simple and convenient for large-scale industrial application.

The invention relates to the technical field of chemical synthesis, in particular to a preparation method of 3, 4 '-diaminodiphenyl ether.The preparation method comprises the steps that m-dinitrobenzene is dissolved with alcohol, and selective hydrogenation is conducted in a high-temperature and high-pressure reaction kettle with a palladium catalyst; and co-heating and refluxing the product after selective hydrogenation, a strong alkali aqueous solution, a first solvent and a phase transfer catalyst to obtain the m-aminophenol salt. M-aminophenol salt, p-nitroiodobenzene, alkali and a second solvent are subjected to a co-heating reaction, and then 3-amino-4 '-nitrodiphenyl ether is obtained through post-treatment; the method comprises the following steps: dissolving 3-amino-4 '-nitrodiphenyl ether with alcohol, carrying out hydrogenation reduction with a palladium catalyst, and carrying out post-treatment purification to obtain 3, 4'-diaminodiphenyl ether. According to the method, common m-dinitrobenzene is used as a raw material, m-nitroaniline is obtained through selective hydrogenation, m-aminophenol salt is prepared through the m-nitroaniline, then etherification reaction is carried out, the reaction yield is higher, the purity is better, and side reactions are few.

The invention relates to the technical field of lithium dihydrogen phosphate, and discloses a method for preparing battery-grade lithium dihydrogen phosphate by using lithium precipitation mother liquor. The method comprises the following steps: (1) mixing a hydrochloric acid solution with a lithium precipitation mother solution until the pH value of the obtained reaction solution is 4-5; (2) heating the reaction solution, adding the sodium phosphate solution into the reaction solution to adjust the pH value to 9-10, and reacting to obtain crude lithium phosphate; (3) adding a phosphoric acid solution into the crude lithium phosphate until the pH value of the obtained mixed solution is 3-5.5; (4) carrying out first reduced pressure evaporation on the crude lithium dihydrogen phosphate solution, and carrying out solid-liquid separation on a first concentrate to obtain a first solid phase and a first mother solution; (5) dissolving the first solid phase in hot water, carrying out second reduced pressure evaporation, and carrying out solid-liquid separation on a second concentrate to obtain a second solid phase and a second mother solution; the solid content of the second concentrate is higher than that of the first concentrate. The lithium dihydrogen acid prepared by the method is high in purity, and the comprehensive yield of lithium is high.

The invention relates to the technical field of organic synthesis, in particular to a method for preparing pyroxasulfone with the IPC classification number of C07D413 / 12, and particularly relates to a method for preparing pyroxasulfone with ozone as an oxidizing agent. The preparation method provided by the invention comprises the following steps: at a certain temperature and pressure, taking ozone as an oxidizing agent, and carrying out oxidation reaction between a compound 1 and the oxidizing agent in the presence of a catalyst to obtain pyroxasulfone. According to the preparation method, ozone is used as an oxidizing agent, ozone can be automatically decomposed into oxygen at normal temperature and normal pressure, and the defect that a hydrogen peroxide solution needs to be treated when hydrogen peroxide is used as the oxidizing agent is avoided, so that the preparation method is environment-friendly, and the defect of harmful emission is overcome; the preparation method disclosed by the invention is high in product purity and yield, simple and easy to control in operation process, and beneficial to industrial application.

The invention discloses an indirect ELISA kit for distinguishing porcine actinobacillus pleuropneumoniae wild virus infection and vaccine immunity and application, and belongs to the technical field of biology. According to the indirect ELISA kit, screened ApxIVA truncated protein serves as a coating antigen, the amino acid sequence of the ApxIVA truncated protein is shown in SEQ ID NO.3, the ApxIVA truncated protein can be subjected to soluble expression in escherichia coli, only one His tag and one S tag are carried, and the structure and the function of the ApxIVA truncated protein are close to those of natural ApxIVA. The pxIVA truncated protein is used as an antigen, an indirect ELISA method and kit for distinguishing APP wild strain infection and gene deletion vaccine immunity are established, the kit has the advantages of high specificity, low background value, low cost and short detection time, and the kit has the advantages of improving animal husbandry APP diagnosis accuracy and improving animal husbandry APP diagnosis accuracy. And the method has important significance in the aspects of optimizing prevention and control measures and guaranteeing animal health and production benefits.

The invention relates to a preparation method of a chlorella exosome as well as a product and application of the chlorella exosome, the preparation method comprises the following steps: (1) mixing extremely micro chlorella with a separation buffer solution, and then carrying out wall breaking treatment to obtain a cell breaking solution; (2) centrifuging the cell disruption liquid, and reserving supernate; and (3) filtering the supernate to obtain the chlorella exosome. The preparation method of the chlorella exosome, provided by the invention, is simple in steps and easy to operate, the chlorella raw material and the specific separation buffer solution are subjected to wall breaking treatment, so that active ingredients in the prepared chlorella can be better extracted, the content of protein and polysaccharide in the obtained exosome is higher, and the purity of the exosome is improved. Meanwhile, gradient centrifugation, filter membrane filtration and the like are assisted in the preparation process, so that the prepared exosome is high in purity and less in impurities.

The invention provides a method for regenerating battery-grade iron phosphate from ferrophosphorus slag after lithium extraction. The method comprises the following steps: carrying out wet reduction leaching on the ferrophosphorus slag, removing impurities from a leaching solution, and roasting to prepare the battery-grade iron phosphate. According to the method, under the condition that impurity elements are not introduced, the leaching reaction of the ferrophosphorus slag is strengthened, and the leaching rate of phosphorus and iron elements can reach 99%; the purification liquid is prepared through impurity removal, the impurity removal rate is as high as 99.93%, and the ferrophosphorus loss rate is as low as 2.44%; and synthesizing the battery-grade iron phosphate from the purified liquid through a regulator. According to the method disclosed by the invention, deep removal of metal ions is realized, and the obtained product is high in purity and can completely meet the use requirements of commercially available battery-grade iron phosphate; and the slag obtained after lithium extraction of the waste lithium iron phosphate battery black powder is used as the battery-grade iron phosphate regeneration raw material, so that the iron phosphate regeneration cost can be reduced, the problems of solid waste stockpiling and landfill are effectively avoided, the resource utilization rate is increased, and deep recycling and green and environment-friendly circulation of the waste lithium battery resource are realized.

The invention discloses a device and a method for preparing a single-walled carbon nanotube by a two-step method. The device comprises a carbon nanotube growth chamber, a product collection module, a catalyst supply module, a carbon source supply module and an etching agent supply module, the carbon source supply module is used for introducing a first airflow containing a carbon source in a first direction, the etching agent supply module is used for introducing a second airflow containing an etching agent in a second direction, and the first direction is opposite to the second direction so that the airflow intersects to form a vortex; the catalyst supply module introduces catalyst particles in a third direction, and the third direction points to the position near the vortex; and the product collecting module is arranged above the vortex and is used for collecting the formed single-walled carbon tubes. Controllable preparation of catalyst nanoparticles and ordered separation of carbon nanotube growth steps are realized, the influence of hybrid variables on the reaction is reduced, the vortex is formed by opposite intersection of airflow, and the problem of local deposition and blockage of tangential laminar flow is avoided by the vortex, so that the influence on the quality and continuous growth of the carbon nanotubes is avoided.

The invention relates to a catalyst for ethylene oxide ring-opening polymerization and a preparation method thereof, and belongs to the technical field of high polymer material synthesis, and the catalyst is a composite structure based on a silicon dioxide nanoparticle loaded bimetal organic complex; a modified nitrogen-containing polydentate ligand is prepared by adopting a special method, is coordinated with metal ions through covalent bonds and is loaded on silicon dioxide nanoparticles; by utilizing the high dispersity and stability of the silicon dioxide nanoparticles and the synergistic catalytic effect of the bimetal organic complex, the catalytic effect is effectively improved, the polymerization process is accelerated, the polymerization stability is enhanced, the polymerization molecular weight is improved, and the distribution is narrow.

The invention provides lithium sulfide as well as a preparation method and application thereof. The preparation method of the lithium sulfide comprises the following steps: providing a mixed solution containing a lithium-containing compound and liquid sulfur which are uniformly mixed, and enabling the mixed solution to be in contact with a reducing gas so as to carry out a lithium sulfide synthesis reaction, after the synthesis reaction of the lithium sulfide is finished, at least removing part of sulfur in the obtained reaction mixture to obtain a crude finished product; and calcining the crude finished product to convert lithium polysulfide in the crude finished product into lithium sulfide to obtain a lithium sulfide product. According to the preparation method provided by the invention, the high-purity lithium sulfide is prepared by a one-pot method, the liquid sulfur is used as a reaction raw material and a reaction solvent, and the whole reaction process does not need to use an organic solvent; according to the method, the lithium salt conversion rate can reach 99% or above, and the purity of the obtained lithium sulfide can reach 99.99% or above; compared with the prior art, the reaction temperature is lower, and low energy consumption and high conversion rate are both considered.

The invention provides a method for preparing high-purity and fine-particle-size lithium sulfide based on carbon thermal reduction. The method comprises the following steps: weighing lithium sulfate monohydrate, an insoluble inorganic carbon source and cysteine in a set proportion to form a raw material mixture; mixing the raw material mixture with water according to a set solid-to-liquid ratio, performing ultrasonic dispersion to obtain homogeneous dispersion liquid, and enabling the dispersion liquid to pass through a nitrogen circulating spray dryer to obtain uniform and dry precursor powder; in a vacuum environment, carrying out segmented calcination to obtain a crude product lithium sulfide; and in a dry and anhydrous environment, washing the crude product lithium sulfide for multiple times by using absolute ethyl alcohol according to a set liquid-solid ratio to obtain an alcoholic solution containing lithium sulfide, and then obtaining lithium sulfide fine powder through a nitrogen circulating spray dryer. The invention solves the problems of side reaction, low purity, large product particles, uncontrollable particle size and the like of lithium sulfide prepared by a carbon thermal reduction method in the prior art.

The invention discloses a low-energy-consumption nitrogen-charging grain storage system and method, and relates to the field of nitrogen-charging grain storage. The method comprises the steps that compressed air is sequentially introduced into a filter set, a drying machine and a micro-oil adsorber to be purified and dried; stripping oxygen O2 molecules and water H2O molecules in the air by using a carbon molecular sieve pressure swing adsorption tower to obtain nitrogen N2 molecular gas; inputting nitrogen N2 molecular gas into a cold drying system, and cooling to a preset temperature range; detecting whether the concentration of the output nitrogen N2 molecular gas meets a preset concentration range or not by using an oxygen analyzer; and when the detected N2 molecular gas concentration of the nitrogen is lower than the lower limit of the preset concentration range, starting a circulating pump to suck the mixed gas in the closed warehouse to the carbon molecular sieve pressure swing adsorption tower for adsorption and nitrogen production again until the N2 molecular gas concentration of the output nitrogen meets the preset concentration range. Aiming at the problem that the nitrogen concentration in nitrogen-filled grain storage is difficult to accurately control in the prior art, accurate control of the nitrogen concentration and yield is realized.

The invention belongs to but is not limited to the technical field of aluminum alloy preparation, and discloses a high-plasticity aluminum alloy prepared from secondary aluminum and a preparation method, high-quality secondary aluminum waste is selected, and obvious impurities are removed; carrying out chemical or mechanical cleaning on the secondary aluminum, and sorting; the pretreated secondary aluminum waste is added into a smelting furnace to be smelted; a purifying agent is added for melt purification; the melt is further purified through inert gas stirring and standing; adding a proper amount of alloy elements into the melt; under the protection of inert gas, uniformly stirring the melt; casting the melt into a cast ingot by adopting a semi-continuous casting or continuous casting process; controlling the cooling speed; carrying out homogenizing heat treatment on the cast ingot to eliminate composition segregation in the cast ingot; and extruding and rolling to obtain the high-plasticity aluminum alloy material. According to the method, the purity of the aluminum alloy is improved, the performance uniformity is enhanced, and the aluminum alloy material with high plasticity and excellent mechanical performance is obtained and is suitable for industrial application with high requirements.

The invention relates to the technical field of vacuum coating, in particular to a vacuum coating machine capable of improving coating purity, which comprises a bearing frame and a coating cavity mounted in the bearing frame, and the coating cavity is of an inverted conical structure; a rotary driving rod is mounted in the middle of the upper part of the coating cavity in a penetrating manner, and a non-contact transmission assembly is mounted above a main mounting rod, so that friction caused by contact is avoided; the interior of the lower portion of the bearing frame is connected with the evaporation source carrying table through a rotary lifting control mechanism. According to the vacuum coating machine capable of improving the coating purity, the cleanliness of a coating area can be improved through the non-contact transmission assembly, so that the coating purity and the product performance can be further improved, airflow generated by pressure difference can be reduced through the arrangement of the hollow interlayer groove, and the situation that the purity and the adhesive force of a formed film are affected due to the fact that tiny dust particles are raised is avoided; therefore, the cleanliness of the coating area can be further improved, and the coating purity is further improved.

The invention discloses a synthesis method of vitamin C ethyl ether, and belongs to the technical field of vitamin derivative synthesis. The synthesis method comprises the following steps: adding vitamin C, benzaldehyde and a catalyst into a first organic solvent, carrying out an aldolization reaction, adding an organic alkali after the aldolization reaction is finished, carrying out a neutralization reaction, adding an alkylation reagent, carrying out an alkylation reaction, and removing the first organic solvent after the alkylation reaction is finished, so as to obtain the vitamin C benzaldehyde. The preparation method comprises the following steps: adding a first organic solvent into a first organic solvent, pulping, filtering, collecting filter residues, washing and drying to obtain 5, 6-O-benzyl-3-O-ethyl-L-ascorbic acid, carrying out hydrogenation deprotection on the 5, 6-O-benzyl-3-O-ethyl-L-ascorbic acid, filtering after hydrogenation deprotection, collecting filtrate, crystallizing, collecting precipitate, washing and drying to obtain the 5, 6-O-benzyl-3-O-ethyl-L-ascorbic acid. The vitamin C ethyl ether is obtained. The synthesis method provided by the invention is simple to operate and high in production efficiency, and the obtained vitamin C ethyl ether is high in yield and purity.

The invention discloses a method for preparing battery-grade iron phosphate and lithium carbonate from a waste lithium iron phosphate battery, and belongs to the technical field of lithium batteries, the method comprises the following steps: slurrying a waste lithium iron phosphate positive electrode material, adding concentrated sulfuric acid for leaching, adding sodium sulfite, controlling reaction potential, and carrying out filter pressing after reaction to obtain a leachate; iron is added into the leachate to remove copper, and copper-removed liquid and copper slag are obtained after filter pressing; adding sodium dihydrogen phosphate into the copper-removed liquid to remove aluminum, and carrying out filter pressing to obtain aluminum slag and impurity-removed liquid; adjusting the pH value of the impurity-removed solution, adding hydrogen peroxide, reacting to obtain an iron phosphate dehydrate precipitate and an iron phosphate mother solution, and treating the iron phosphate dehydrate to obtain battery-grade anhydrous iron phosphate; adjusting the pH value of the iron phosphate mother liquor, carrying out filter pressing to obtain impurity-removed slag and a lithium sulfate solution, adding sodium carbonate into the lithium sulfate solution, carrying out heating reaction, filtering slurry to obtain a lithium carbonate wet material, and treating to obtain battery-grade lithium carbonate. According to the method, the problem of recycling the waste lithium iron phosphate battery material iron phosphate is solved, and comprehensive recycling of the iron phosphate and the lithium material is realized.

The invention discloses industrial-grade mixed oil produced by utilizing kitchen waste oil and a preparation method of the industrial-grade mixed oil, and belongs to the technical field of recycling of the kitchen waste oil. The invention relates to industrial-grade mixed oil produced by using kitchen waste oil and a preparation method thereof, and the preparation method comprises the following steps: firstly collecting kitchen waste containing the waste oil, and storing the kitchen waste in a container through special equipment; carrying out screen solid-liquid separation, cleaning grease on the surface of the solid waste, and then carrying out precipitation separation; then carrying out centrifugal separation, chemical cleaning, water washing, acid treatment, dehydration, degumming and metal ion removal on the separated grease and oil-containing liquid; carrying out ultrasonic-assisted multistage ester exchange after enzymolysis optimization, carrying out membrane separation on glycerol and fatty acid methyl ester, and carrying out reduced pressure distillation to obtain a high-purity fraction; carrying out adsorption refining, plasma treatment and supercritical fluid extraction; finally, nano particles are added and blended with additives, efficient recycling of the kitchen waste oil is achieved, and then high-purity industrial-grade mixed oil is prepared.

The invention relates to the technical field of preparation methods of polypeptide drugs, and provides a solid-phase preparation method of tirpotide, which comprises the following steps: by taking amino resin as initial resin, sequentially coupling amino acid and small-fragment peptide according to an amino acid sequence of the tirpotide by using a solid-phase synthesis method to synthesize tirpotide resin; and cracking and purifying the tilpotide resin to obtain a pure tilpotide product. Wherein the small fragment peptide is 1-4 tetrapeptide fragment Boc-Tyr (tBu)-Aib-Glu (OtBu)-G1y-OH, 5-6 dipeptide fragment Fmoc-Thr (tBu)-Phe-OH, 7-8 dipeptide fragment Fmoc-Thr (tBu)-Ser (tBu)-OH, 10-11 dipeptide fragment Fmoc-Tyr (tBu)-Ser (tBu)-OH, 12-13 dipeptide fragment Fmoc-Ile-Aib-OH, 17-18 dipeptide fragment Fmoc-Lys (AEEA-AEA-gamma-Glu (alpha-OtBu)-Ecosanoic acid (mon-tBu), 20 side chain peptide Fmoc The coupling agent coupling the amino acid and the small fragment peptide is selected from the group consisting of Oxyma and DIC, TPTU and TMP or COMU and DIEA. The crude product of the tirpotide prepared by the method disclosed by the invention is high in yield and high in purity.

The invention discloses a surface acoustic wave resonator and a filter, and the resonator comprises an interdigital structure which comprises a first interdigital region and a second interdigital region; the first interdigital area comprises a plurality of first finger strips, and the second interdigital area comprises a plurality of second finger strips; the reflecting gratings are arranged on the two sides of the interdigital structure in the first direction, and the reflecting gratings, the first finger strips and the second finger strips are located on the same plane; the reflecting grating and the plurality of first finger strips are vertically crossed with each other, and the reflecting grating and the plurality of second finger strips are vertically crossed with each other; in the first direction, each first finger strip and each second finger strip are oppositely arranged, and a gap is formed between each first finger strip and the corresponding second finger strip; in the second direction, the multiple first finger strips are arranged in parallel, and the multiple second finger strips are arranged in parallel; the first direction is perpendicular to the second direction. According to the invention, the leakage of transverse energy in the first direction can be reduced, and the high-order stray mode of the surface acoustic wave resonator in the first direction and the second direction can be suppressed.

The invention provides a method for synthesizing tirpotide by adopting a solid-liquid combination strategy. The preparation method comprises the following steps: firstly, respectively synthesizing full-protection peptide fragments (1-17) and (18-39), and then carrying out liquid-phase splicing and deprotection to obtain crude peptide; according to the strategy, the synthesis period can be remarkably shortened, large-scale industrial production is facilitated, meanwhile, the synthesis yield is high, and the purity and content of the obtained crude peptide are high.

The invention belongs to the technical field of biology, and particularly relates to an extraction method of polydeoxyribonucleotide, which comprises the following steps: carrying out homogenate treatment on pretreated in-vitro testis tissue, filtering the obtained homogenate, adding a pancreas extract into the filtrate, and stirring to obtain enzymatic hydrolysate; and precipitating protein in the enzymatic hydrolysate, removing the protein, adding sodium acetate for treatment, adding absolute ethyl alcohol for precipitation, centrifuging, washing the obtained precipitate, and drying to obtain the product. Common trypsin and lipase in fish pancreas are beneficial to release of DNA, the fish pancreas extract is applied to extraction of the polydeoxyribonucleotide, the extraction time can be remarkably shortened, the yield can be increased, meanwhile, nuclease in the fish pancreas extract can effectively degrade DNA, and small-fragment polydeoxyribonucleotide is obtained.

The invention discloses a synthetic method of a water soluble ultraviolet light absorber BP-9. The method mainly comprises the following process steps: (1) carrying out methylation on the main raw materials of 2, 2', 4, 4'-tetrahydroxyl benzophenone, a transition metal salt catalyst and a mixed solvent which is prepared from dichloroethane and anhydrous ethanol in equal parts by weight to obtain 2, 2'-dihydroxyl-4, 4'-dimethoxyl benzophenone; (2) carrying out sulfonation reaction on the main raw materials of methylate, sulfamic acid and C1-C3 halohydrocarbon to obtain 2, 2'-dihydroxyl-4, 4'-dimethoxyl benzophenone-5, 5'-disulfonic acid; and (3) carrying out neutral reaction on the main raw materials of sulfonated product, inorganic base and ethanol water to finally obtain the BP-9 product. The synthetic method disclosed by the invention is few in reaction step, low in cost, high in product purity and stable in quality, and raw materials are easily available.

The invention provides a preparation method of an acid-resistant and chlorine-corrosion-resistant porous composite electrode and a device constructed on the basis of the electrode and used for preparing hydrogen and chlorine by electrolyzing a sodium chloride solution, two cavities are provided, an acid or neutral saturated sodium chloride solution is filled in the cavities, the cavities are separated by a proton exchange membrane or a diaphragm, and the proton exchange membrane or the diaphragm is filled in the cavities. And in the electrolysis process, the cathode generates high-purity hydrogen, the anode generates high-purity chlorine, the chlorine is absorbed by sodium hydroxide in the gas collection bottle and generates sodium hypochlorite, or the chlorine is introduced into a sodium bromide / sodium iodide solution to replace bromine / iodine elementary substances, and the chlorine is discharged from the gas collection bottle. The sodium hypochlorite solution and the bromine / iodine water are used for disinfection and sterilization experiments. The corrosion-resistant porous composite electrode for electrolysis of an acidic or neutral saturated sodium chloride solution is prepared, the electrolysis voltage of the corrosion-resistant porous composite electrode is further reduced by loading a cathode / anode catalyst, and an acidic or neutral saturated sodium chloride solution electrolysis device constructed based on the electrode can be used for preparing high-purity hydrogen and chlorine.

The invention relates to a crystallization method of ammonium metavanadate crystals. The crystallization method comprises the following steps: cooling an ammonium metavanadate concentrated solution to obtain an ammonium metavanadate supersaturated solution; the cooling treatment process comprises the step of adding a crystallization regulating agent into the ammonium metavanadate concentrated solution; sequentially carrying out aging treatment and solid-liquid separation on the ammonium metavanadate supersaturated solution to obtain an ammonium metavanadate solid phase; by adding a crystallization regulating agent in the cooling treatment process, regulating the growth rate and growth direction of ammonium metavanadate crystals, matching with the steps of aging treatment and the like, the crystallization rate of the crystallization method is improved, preferably, the crystallization rate is up to 89.5% or above, and the high-purity ammonium metavanadate product with large grain size and regular morphology is obtained. Wherein the median particle size preferably reaches up to 86.5 microns or above, the purity reaches up to 99.97% or above, and the requirement for high-quality vanadium products at present is met.

The invention discloses a method for preparing a composite iron-based polyanion positive electrode material. The structural formula of the positive electrode material is represented as Na4Fe3 (PO4) 2 (P2O7) (at) Camp, mXenes are sodium ferric pyrophosphate compositely coated by an MXenes material and a carbonaceous precursor, and the preparation method comprises the following steps: weighing a sodium source, a ferrous source, a phosphorus source and a carbon source according to a stoichiometric ratio, uniformly mixing, grinding, spray-drying and sintering at high temperature to obtain the composite iron-based polyanion positive electrode material, and the carbon source comprises iron-nickel doped polyethylene glycol. The composite iron-based polyanion positive electrode material provided by the invention is remarkably improved in the aspects of energy density, rate capability and cycle life, and the preparation process is simple to operate, reliable in flow, quick in preparation process and easy for industrial production, so that an ideal scheme is provided for commercialized sodium ion battery positive electrode materials.

The invention discloses a gemigliptin oxalate and a crystal form, a preparation method and application thereof, relates to the technical field of medicinal chemistry, and provides the crystal form of the gemigliptin oxalate, the crystal form is not reported in the prior art, and animal experiments show that compared with gemigliptin tartrate and gemigliptin hydrochloride, the crystal form of the gemigliptin oxalate has the advantages that the crystal form of the gemigliptin oxalate is more stable. The gemigliptin oxalate prepared by the invention has better pharmacokinetic performance, and lays a foundation for development and application of a new dosage form of gemigliptin; the invention further provides a simple and efficient gemigliptin salt forming process, compared with a method for removing an amino protecting group through acid treatment, the salt forming process provided by the invention does not need to add alkali to dissociate the amino group, impurity generation caused by strong acid or strong alkali is avoided, and the prepared gemigliptin oxalate is high in purity.

The invention belongs to the field of medical chemistry, and particularly relates to a crystal form of a heterocyclic compound and a pharmaceutical composition thereof. Specifically, the invention relates to a crystal form of 4-((2R, 3S, 5R)-3-(3, 4-difluoro-2-methoxyphenyl)-5-methyl-5-(trifluoromethyl) thiacyclopentane-2-formamido) pyridine-2-formamide and a pharmaceutical composition of the crystal form of 4-((2R, 3S, 5R)-3-(3, 4-difluoro-2-methoxyphenyl)-5-methyl-5-(trifluoromethyl) thiacyclopentane-2-formamido) pyridine-2-formamide. The crystal form is good in crystallinity, excellent in chemical stability and crystal form stability, high in process safety and capable of playing a good drug effect in various animal models.

The invention provides a system for preparing a single-walled carbon nanotube based on a pulsed plasma arc, which can improve the yield of the single-walled carbon nanotube. Two electrode module groups are arranged in an electric arc reaction cavity and are respectively used as an anode and a cathode, and a pulse power supply drives a motor module group to generate a pulse plasma electric arc; a pulse plasma arc is used as a heat source, a mixed solution of a catalyst and a catalyst auxiliary agent is atomized and then is fed into an arc reaction cavity by using carrier gas to react with a gaseous carbon source which is independently fed, and a high-purity single-walled carbon nanotube is grown on the surface of the fine catalyst through plasma flow between a cathode and an anode and a cracked carbon source, so that the high-purity single-walled carbon nanotube is obtained. And a produced product is obtained in a collection chamber at the tail end of the system. Meanwhile, the invention also discloses a method for preparing the single-walled carbon nanotube based on the pulse plasma arc.