Abstract: Disclosed are a borohydride reduction stabilizing system and a method for reducing an ester to an alcohol. The borohydride reduction stabilizing system includes: a borohydride reducing agent and a stabilizing agent for stabilizing the borohydride reducing agent. The borohydride reducing agent is sodium borohydride or potassium borohydride. The stabilizing agent is an alkali metal salt of an alcohol. By adding the alkali metal salt of the alcohol, such as sodium alkoxide or potassium alkoxide, on the basis of an existing sodium/potassium borohydride reducing agent, the sodium/potassium borohydride reducing agent may be kept stable without being decomposed under the condition of increased temperature, so that on the one hand, the reducing activity is maintained in a relatively high state, and the condition of excessive use is reduced, and on the other hand, the generation of hydrogen is reduced, and the process risks are reduced.

Abstract: The present application provides a processing method of a metal composite structure including a first metal layer and a second metal layer stacked on the first metal layer. The processing method includes the steps of defining a first through hole in the first metal layer, and drilling in the first through hole toward the second metal layer to form a traction hole in the second metal layer. Then, hot melt drilling is performed on a surface of the second metal layer away from the first metal layer toward the first through hole, thereby causing the second metal layer to crack under a traction force of the traction hole to form a second through hole, and a portion of the second metal layer to be melted and squeezed to form a bushing which adheres to at least a portion of a sidewall of the first through hole.

Abstract: Provided are an esterase mutant and the use thereof. The esterase mutant obtained by means of rational design and several rounds of evolution screening with enzymes on the basis of an amino acid sequence as shown in SEQ ID NO: 1 is changed in terms of protein structure and function compared with a wild-type esterase; in practical use, the catalytic activity and/or stereoselectivity of the esterase mutant is greatly improved; and when a system contains some organic cosolvents, the esterase mutant still has relatively stable catalytic activity and/or stereoselectivity. In addition, the improvement of the catalytic activity and/or stereoselectivity of the esterase mutant reduces the use amount of the enzyme to a certain extent and reduces the difficulty of post-treatment, and therefore the esterase mutant is suitable for industrial production.

Abstract: Provided are an immobilized enzyme and an application thereof in continuous production. The immobilized enzyme is a Polyethyleneimine (PEI)-modified immobilized enzyme, and includes: an enzyme, which includes Amine Dehydrogenase (AmDH) and/or Formate Dehydrogenase (FDH); and a carrier, which is a cyanuric chloride-activated amino carrier. The problem in the prior art of poor performance of an immobilized enzyme is solved, the catalytic activity and reusability of the immobilized enzyme are improved, and the immobilized enzyme is suitable for the field of enzyme immobilization.

Abstract: A nonlinear optical crystal structure is provided. The nonlinear optical crystal structure includes a plurality of two-dimensional material films, wherein the plurality of two-dimensional material films are stacked in a direction perpendicular to a two-dimensional plane thereof, and two-dimensional material films adjacent to each other are bonded by van der Waals forces, each of the plurality of two-dimensional material films is a crystal with a center-inversion-asymmetric crystal structure, and has a predetermined lattice orientation parallel to the two-dimensional plane in a direction parallel to the two-dimensional plane, there is a non-zero twist angle between the two-dimensional material films adjacent to each other, and the twist angle is an included angle between predetermined lattice orientations of the two-dimensional material films adjacent to each other in the same two-dimensional plane, and a thickness of each of the plurality of two-dimensional material films is greater than 5 nm.

Abstract: A method for continuously synthesizing N-Boc-2,5-dihydropyrrole is provided. The method includes the following steps: cis-1,4 dichloro-2 butene is dissolved in an organic solvent, to prepare solution A; urotropine is dissolved in an organic solvent, to prepare solution B; the solution A and solution B are fed into a first continuous reaction device; a product overflow system is transferred to a second continuous reaction device, and concentrated hydrochloric acid is fed into the same; a product overflow system of the second continuous reaction device is transferred to a third continuous reaction device, and potassium carbonate is fed into the same; a product overflow system of the third continuous reaction device is transferred to a fourth continuous reaction device, and Boc acid anhydride solution is fed into the same; and a product of the fourth continuous reaction device is subjected to continuous solid-liquid separation, concentration and distillation, to obtain N-Boc-2,5-dihydropyrrole.

Abstract: Disclosed are a monooxygenase mutant and use thereof. An amino acid sequence of a monooxygenase mutant is an amino acid sequence obtained by mutating an amino acid sequence as shown in SEQ ID NO: 1. Mutation includes at least one of the following mutation sites: site 49, site 60, site 61, site 144, site 145, site 146, site 147, site 167, site 169, site 189, site 246, site 247, site 280, site 284, site 285, site 286, site 287, site 328, site 330, site 332, site 382, site 427, site 428, site 429, site 430, site 431, site 432, site 433, site 434, site 435, site 436, site 438, site 441, site 493, site 494, site 508, site 509, site 510, site 511, site 512, and site 513 sites and the like.

Abstract: Provided is a ketoreductase mutant and a method for producing chiral alcohol using the same. The ketoreductase mutant has a sequence with amino acid mutations in the sequence shown in SEQ ID NO:1. The mutation sites include at least one of the following positions: 6th position, 21st position, 42nd position, 58th position, 61st position, 76th position, 87th position, 94th position, 96th position, 108th position, 113th position, 117th position, 144th position, 146th position, 147th position, 149th position, 151st position, 152nd, 156th position, 165th position, 177th position, and 198th position.

Abstract: Provided are a transaminase mutant and an application thereof. The transaminase mutant has an amino acid mutation based on a sequence shown in SEQ ID NO: 1, the amino acid mutation being a single position mutation from among W60Y, Y168A, V379W, V379L, V379M, C418Q and C418W or a combination thereof. The activity, stability, and tolerance to temperature, pH and organic solvents of such transaminase mutants are improved. The present application solves the problem of poor tolerance of extreme environments by transaminase in the prior art, and is suitable for the field of enzyme engineering.

Abstract: Provided are a lipase mutant and an application thereof. Specifically, one or more mutations selected from A262H, A338V, V3641, A158PN, and 1159N are generated on the basis of an amino acid sequence as shown in SEQ ID NO: 1; and compared with a parental lipase, a change in the structure and function of a protein occurs in the lipase mutant, and the stereoselectivity is improved, such that a usage amount of an enzyme is decreased to a certain extent, the post-treatment difficulty is reduced, and the lipase mutant is suitable for industrial production.

Abstract: Provided are a transaminase mutant and a method for producing a chiral amine using the same. An amino acid sequence of the transaminase mutant is an amino acid sequence obtained by mutation occurred in an amino acid sequence as shown in SEQ ID NO: 1, and the mutation includes at least one of the following mutation sites: position 3, position 5, position 8, position 25, position 32, position 45, position 56, position 59, position 60, position 84, position 86, position 164, position 176, position 178, position 180, position 187, position 197, position 206, position 207, position 242, position 245, position 319 and position 324.

Abstract: Provided is a continuous synthesis method for 1,1?-bicyclic[1.1.1]pentane-1,3-diethyl ketone compounds. The continuous synthesis method comprises: under the irradiation of a light source, continuously conveying raw material A and raw material B to a continuous reaction device for a continuous photochemical reaction to obtain 1,1?-bicyclic[1.1.1]pentane-1,3-diethyl ketone compounds, and controlling the reaction temperature in the continuous reaction device by a temperature control device during the continuous photochemical reaction. A propellane with substituents, as a reaction raw material, is subjected to the above photochemical reaction in the continuous reaction device to reduce the probability of its slow decomposition and deterioration under the irradiation, and greatly improve the conversion rate of the reaction material and product yield.

Abstract: Disclosed are a modified epoxy resin immobilized enzyme, a preparation method therefor and an application thereof. Herein, the preparation method includes the following steps: modifying an epoxy resin, adding a polyethyleneimine to a modified epoxy resin for further modification, and then adding an enzyme to be immobilized and a glutaraldehyde for immobilization, to obtain the modified epoxy resin immobilized enzyme. The epoxy resin is modified, the polyethyleneimine is added to the modified epoxy resin for the further modification, and an aldehyde group in the resin and an amino group in the polyethyleneimine are covalently bound to each enzyme, then it is activated by the bifunctional reagent glutaraldehyde.

Abstract: An amino acid sequence of the monooxygenase mutant is obtained by mutation of an amino acid sequence shown in SEQ ID NO: 1, and the mutation at least includes one of the following mutation sites: 45-th site, 95-th site, 106-th site, 108-th site, 114-th site, 186-th site, 190-th site, 191-th site, 249-th site, 257-th site, 393-th site, 436-th site, 499-th site, 500-th site, 501-th site, 503-th site, 504-th site, 559-th site, and 560-th site.

Abstract: A memory with built-in synchronous-write-through (SWT) redundancy includes a plurality of memory input/output (IO) arrays, a plurality of SWT circuits, and at least one spare SWT circuit. The at least one spare SWT circuit is used to replace at least one of the plurality of SWT circuits that is defective.

Abstract: Provided is a preparation process of diazomethane. The preparation process includes: step S1, taking N-methylurea as a raw material to continuously prepare, in a continuous reactor, a first product system containing N-methyl-N-nitrosourea: step S2, performing continuous extraction and continuous back-extraction on the first product system to obtain an N-methyl-N-nitrosourea solution; step S3, enabling the N-methyl-N-nitrosourea solution to continuously react with an alkaline solution in a continuous reactor to obtain a second product system containing the diazomethane; and step S4, performing continuously liquid separation, water freezing and removal on the second product system, to obtain the diazomethane.

Abstract: The present invention provides a method for synthesizing a fluorine-containing chiral amine compound. The method comprised: reacting an amino donor with a fluorine-containing dihydroxy ketal compound under a catalysis of a transaminase to generate the fluorine-containing chiral amine compound, wherein the transaminase is derived from a plurality of strains. The transaminase of the present application has substrate specificity on the fluorine-containing dihydroxy ketal compound, and may effectively catalyze this type of the substrate to be converted into the fluorine-containing chiral amine compound. In addition, the transaminase has catalytic activity on a plurality of the fluorine-containing dihydroxy ketal compounds, and is relatively high in reaction selectivity and activity. The method catalyzed by the bio-enzyme is not only short in route, but also high in product yield, and the production using the method reduces cost, organic solvents and three wastes.

Abstract: The present disclosure describes a semiconductor device with a fill structure. The semiconductor structure includes first and second fin structures on a substrate, an isolation region on the substrate and between the first and second fin structures, a first gate structure disposed on the first fin structure and the isolation region, a second gate structure disposed on the second fin structure and the isolation region, and the fill structure on the isolation region and between the first and second gate structures. The fill structure includes a dielectric structure between the first and second gate structures and an air gap enclosed by the dielectric structure. The air gap is below top surfaces of the first and second fin structures.

Abstract: A memory includes a memory array and a single-ended sense amplifier circuit. The memory array includes wordlines, bitlines, and memory cells. The bitlines include a first bitline, routed on a first metal layer but not a second metal layer, and a second bitline, routed on the first metal layer and the second metal layer. Each of the memory cells is coupled to one of the wordlines. The memory cells include a first group of memory cells, coupled to the first bitline, and a second group of memory cells, coupled to the second bitline, where the first group of memory cells and the second group of memory cells are located at a same column. The single-ended sense amplifier circuit performs a read operation upon a target memory cell through single-ended sensing when a selected wordline is enabled.

Abstract: Provided is an amination method for a polystyrene-type resin, and a method for immobilizing an enzyme using an aminated polystyrene-type resin. The amination method includes: in a solvent, a catalyst is used to catalyze a polystyrene-type resin and an enamine salt to perform a Friedel-Crafts alkylation reaction, to obtain an aminated polystyrene-type resin, herein the catalyst is a Lewis acid catalyst. By means of the Friedel-Crafts alkylation reaction, the enamine salt is grafted onto the polystyrene-type resin, and the polystyrene-type resin is aminated. The conditions of the Friedel-Crafts alkylation reaction are easy to control, the post-treatment process is simple, and it is only necessary to remove the catalyst and the unreacted enamine salt by washing. Therefore, the above amination method in the present application has few steps and is simple and easy to implement. Meanwhile, the amination method further avoids the use of a noble metal catalyst, thereby reducing production cost.