8results about How to "The preparation method is safe" patented technology

According to the method, a one-pot copolymerization method is adopted, MBAA and borax serve as cross-linking agents, zwitterionic polyelectrolyte hydrogel containing SBMA, PVA, THMA and AMPS is prepared, and the zwitterionic polyelectrolyte hydrogel has excellent adhesion performance and biocompatibility and is suitable for the field of biological medicine. According to the method, the physical characteristics of the hydrogel are enhanced due to crosslinking sites and hydrogen bonds of polyvinyl alcohol. The cationic and anionic groups of SBMA improve the adhesion performance, and the reaction monomer THMA provides hydrogen-bond interaction to further promote adhesion, so that the prepared hydrogel adhesive shows excellent adhesion performance and biocompatibility, and is suitable for biological medicine application of wound dressing, drug release systems, tissue engineering and the like.

The invention provides a preparation method of a perovskite thin film, and the method comprises the steps: providing an initial film layer which comprises a first surface and a second surface which are opposite to each other; a coating material is provided, the coating material comprises lead halide and a pore-forming agent, and the pore-forming agent has dehydration property; the coating material forms a porous lead halide framework layer with preset porosity on the first surface of the initial film layer through an evaporation process; coating one side, deviating from the initial film layer, of the porous lead halide framework layer with an organic amine salt mixed solution, and reacting to form an initial perovskite thin film; and performing first type annealing treatment on the initial perovskite thin film to form the perovskite thin film. By adopting the method, the film forming quality of the perovskite film can be effectively improved, and the electrical property of the solar cell can be ensured and improved. The invention also discloses a perovskite cell, a laminated cell and a preparation method thereof.

The application discloses a preparation method and application of a pyridine derivative compound, belongs to the technical field of chemical synthesis, and has the structural formula as shown in the following formula: wherein the R1 group is one of 4-CH3, 4-OCH3, 4-F, 4-Cl and 4-Br; the R2 group is one of -C5H9 and -C6H 11 ; and the R3 group is one of 3-F, 3-H and 3-CH3. The pyridine derivative compound prepared by the application has a pyridine ring as a structural center and has very important medicinal value and is widely applied in the fields of antitumor, anticancer, antibacterial and other biological medicines.

The invention belongs to the technical field of biological enzyme engineering, and particularly relates to a glycosyl transferase mutant and application thereof in synthesis of rebaudioside M. According to the invention, site-directed mutagenesis is carried out on an amino acid sequence SEQ ID NO.1 of wild type glycosyl transferase, and mutants: I29M, L149C and F374C are obtained through screening; the invention also provides a nucleic acid sequence for coding the mutant, an expression vector and a recombinant strain which are used for catalytically converting rebaudioside D to prepare rebaudioside M, and the conversion rate is obviously improved. Experimental results show that under optimized reaction conditions, the mutant can increase the conversion rate of converting rebaudioside D into rebaudioside M to 100%, which is increased by more than 30% compared with a wild type, and the mutant has significant industrial application value.

The application discloses diatomite-derived silicon-carbon negative electrode material and a preparation method thereof and application in lithium ion batteries, and belongs to the technical field of lithium ion battery negative electrode materials. The method discloses the diatomite and the pitch as raw materials by adopting magnesium heat treatment, and the diatomite-derived silicon-carbon negative electrode material is obtained through specific composite process and calcination treatment. The method can uniformly coat the carbon material on the inner and outer surfaces of the porous micron-sized silicon negative electrode, solves the technical problems of the existing silicon-carbon negative electrode material nano-particle agglomeration and the carbon material coating only on the outer surface, and achieves the beneficial effects of further improving the conductivity and structural stability of the composite material.

According to the europium-doped sodium lithium phosphate photoluminescence material and the preparation method thereof, the preparation raw materials and the preparation method are simple, safe and low in cost, a powder sample shows good characteristics of the photoluminescence material, a photoluminescence signal has high sensitivity and stability, and the photoluminescence signal has high sensitivity and stability by adopting the heating temperature of 650-700 DEG C and the heating time of 8-10 h. Higher photoluminescence sensitivity can be obtained; the total photoluminescence response of the synthesized europium-doped sodium lithium phosphate photoluminescence material fluctuates less than 3% within 24 h after irradiation, and the lowest detection limit is 0.68 [mu] Gy, which reaches the international advanced level. According to the invention, the problems of low sensitivity and poor stability of most photoluminescence materials at present can be solved, and a solid guarantee is provided for the accuracy of the material applied to nuclear radiation dose monitoring and traceability.

The application discloses a one-pot preparation method of 3,4,5-trifluorobromobenzene. In an organic solvent, 2,6-difluoroaniline is used as raw material to obtain the product 3,4,5-trifluorobromobenzene through three steps of bromination, diazotization and fluorination at a certain temperature. The method has the advantages of multiple raw material sources, obvious cost advantage, safety and convenience, high total yield, less waste and the like, and is beneficial to industrialization.

The invention relates to the technical field of shielding materials, and to a preparation method and material of a biomass carbon / silver composite electromagnetic shielding material, comprising: using hexadecyl trimethyl ammonium bromide solution to treat wood materials, and carbonizing the wood materials after the treatment to obtain biomass carbon; using hydrochloric acid solution, trishydroxymethylaminomethane solution and dopamine hydrochloride to prepare dopamine monomer solution, and using hydrogen peroxide solution and the prepared dopamine monomer solution to modify biomass carbon to obtain polydopamine-modified biomass carbon; using silver nitrate solution and ammonia solution to prepare silver ammonia solution, and immersing polydopamine-modified biomass carbon in the silver ammonia solution, adjusting the pH value of the silver ammonia solution, adding glucose solution, and ultrasonically reacting to obtain biomass carbon / silver composite electromagnetic shielding material. The invention can deposit silver nanoparticles on the surface and internal pores of biomass carbon modified by polydopamine, and has excellent electromagnetic shielding capabilities in both dual bands.