Abstract: The present disclosure relates to the technical field of biotechnology, in particular to carbonyl reductase mutant and its application. Specifically, the present disclosure provides a carbonyl reductase mutant for catalyzing the preparation of (R)-8-chloro-6-hydroxyoctanoic acid ethyl ester from 8-chloro-6-oxooctanoic acid ethyl ester. The mutant protein is a non natural protein and undergoes mutations in three core amino acids related to enzyme catalytic activity in the initial carbonyl reductase. The advantageous effect of the present disclosure is that the carbonyl reductase mutant provided by the present disclosure has the characteristic of efficiently catalyzing the preparation of the precursor substance (R)-8-chloro-6-hydroxyoctanoic acid from 8-chloro-6-oxooctanoic acid ethyl ester, and can efficiently catalyze the oxidation-reduction reaction of 8-chloro-6-oxooctanoic acid, with a product space-time yield of 99.9 g·L?1·h?1 or more.

Abstract: Provided are an unequal-channel angular self-bending extrusion die and a method for designing and manufacturing the same and extrusion method thereof and includes following steps: designing a symmetrical streamlined extrusion die based on sine function; making the medial axis of the die cavity of the symmetrical streamlined extrusion die twisted and deformed on a certain plane; establishing the die cavity wall surface equation of the unequal-channel angular self-bending extrusion die; setting a working belt structure downstream the die cavity of the unequal-channel angular self-bending extrusion die.

Abstract: A magnetic field-assisted vibratory finishing device for a minute structure and a finishing method is provided. The device includes a rotating shaft, a workpiece clamping device, a magnetic field generating device, a vibration assisting device, a three-axis precision displacement platform and a base. The magnetic field generating device includes a baffle plate, magnetic bars and a magnetic-pole groove. The vibration assisting device includes a housing, guide fixing rods, a vibration motor, a vibration connecting plate, and compression springs. The workpiece clamping device clamps parts with a variety of structural shapes, and a frequency controller can control the motion mode of the magnetic field generating device during the finishing processing, thereby controlling the motion track of grinding material.

Abstract: A controllable magnetic field-assisted finishing apparatus for an inner surface and a finishing method are provided. The apparatus includes a housing, ball screw mechanisms, a workpiece, a centering clamp, a connecting plate, a magnetic field generating device, a chuck clamp, a precise displacement platform and a base. The magnetic field generating device includes electromagnetic coils, coil connecting plates, a magnetic yoke, nuts, springs and bolts. The magnetic field generating device dynamically adjusts a distance from the magnetic yoke to the outer surface of the workpiece through the springs. The movement tracks of the magnetic finishing medium are controlled by the formed rotation of the magnetic field, the finishing action force dynamic-adjustment, the optimization of the machining form of the magnetic finishing medium in collaboration with the rotation of the chuck clamp and the feed movement of the precise displacement platform.

Abstract: A large-load unmanned aerial vehicle (UAV) for plant protection with adjustable spraying swath and pesticide application amount is provided, relating to the technical field of pesticide application of unmanned aerial vehicles. The large-load unmanned aerial vehicle for plant protection comprises a large-load unmanned aerial vehicle, a pesticide box, a variable pesticide application system, and adjustable spraying swath mechanisms, wherein the pesticide box is fixed to landing gears of the unmanned aerial vehicle and is positioned below a control platform of the unmanned aerial vehicle; the adjustable spraying swath mechanisms are arranged on the landing gears, the variable pesticide application system is connected with the pesticide box and the adjustable spraying swath mechanisms, the variable pesticide application system and the adjustable spraying swath mechanisms are electrically connected with the control platform, and the control platform is in communication connection with a remote control handle.

Abstract: A large-load unmanned aerial vehicle (UAV) for plant protection with adjustable spraying swath and pesticide application amount is provided, relating to the technical field of pesticide application of unmanned aerial vehicles. The large-load unmanned aerial vehicle for plant protection comprises a large-load unmanned aerial vehicle, a pesticide box, a variable pesticide application system, and adjustable spraying swath mechanisms, wherein the pesticide box is fixed to landing gears of the unmanned aerial vehicle and is positioned below a control platform of the unmanned aerial vehicle; the adjustable spraying swath mechanisms are arranged on the landing gears, the variable pesticide application system is connected with the pesticide box and the adjustable spraying swath mechanisms, the variable pesticide application system and the adjustable spraying swath mechanisms are electrically connected with the control platform, and the control platform is in communication connection with a remote control handle.

Abstract: Disclosed is an organic amine salt foaming agent, that is, a composite polyurethane foaming agent, comprising: 1) hexafluorobutene; and 2) an alkanolamine salt mixture (MAA), the alkanolamine salt mixture (MAA) contains an organic amine salt compound having the following general formula (I): An?[Bm+]p (I); wherein An? is one or two or three selected from the following anions: (b) carbonate: CO32?; (c) formate: HCOO?; (d) bicarbonate: HO—COO?. A polyurethane foaming method using carbon dioxide and an organic amine in combination is also disclosed, in which carbon dioxide is added to a polyurethane composition for foaming. A method for preparing an alkanolamine carbonate salt with low water content from ammonium carbonate and an epoxide is additionally disclosed, in which a liquid alkanolamine salt mixture is used as a dispersion medium or as a solvent for reaction raw material.

Abstract: A shrimp shell separation and cleaning device for Euphausia superba comprises a hollow main body; a screening cylinder installed rotationally inside the main body and having a bottom installed with a filter screen; a stirring assembly provided rotationally inside the main body and comprising a cylindrical cam installed inside the screening cylinder, wherein a sleeve frame is sleeved over the cylindrical cam, stirring rods are provided on the sleeve frame in an array mode and rotationally installed on the sleeve frame through driving grooves, the driving grooves run through the sleeve frame and each have one end, which penetrates through the sleeve frame, rotationally installed in one driving groove of the cylindrical cam, and the sleeve frame is arranged in self-rotating manner; a feeding port installed fixedly on communicating with the main body; and a spray head arranged fixedly inside the main body for spraying water into the screening cylinder.

Abstract: An driving motor with hybrid excitation of electromagnetism and invisible magnetic pole, wherein each magnetic pole comprises two first magnets, one second magnet and one third magnet; wherein the first magnet is placed along a diameter direction of a rotor core, the second magnet is located at a middle and lower portion of two first magnets of each magnetic pole corresponding to the second magnet at a diameter direction, and a magnetic isolation groove is disposed at an inner end of the first magnet and extends toward two sides of the inner end of the first magnet. The magnetic isolated air gap can adjust a spatial distribution of a magnetic field generated by permanent magnets of each pole to replace the permanent magnets, so as to save the number of the permanent magnets, reduce the weight of the motor, and reduce the cost of the motor.

Abstract: The present invention discloses an opposite belt-type precise seeding device. The opposite belt-type precise seeding device comprises a seed metering tube consisting of a U-shaped shell and a cover plate, two conveying devices provided inside the seed metering tube in parallel, and a conveying plate provided at the lower end of the seed metering tube. The opposite belt-type precise seeding device belongs to the field of agricultural machinery. In a seeder, a tubular seed conveying tube is usually used for guiding movement of seeds, but the movement of the seeds in the seed conveying tube has certain randomness, so that the seed distance consistency of the seeds in a seed bed is reduced. Through control of the seeds by the conveying devices, the stable movement of the seeds is achieved and the seed distance consistency of the seeds in the seed bed is guaranteed.

Abstract: The disclosure relates to a method for producing levulinic acid in a molten salt hydrate from cellulose hydrolysis. An inorganic molten salt hydrate was prepared by mixing an inorganic salt with water, cellulose is added and stirred to dissolve, a solid catalyst is added and heated up for reaction to obtain a reactant, the reactant is cooled and subjected to a separation to obtain the levulinic acid, and the inorganic molten salt hydrate and the solid catalyst obtained after the separation are recycled, wherein the inorganic salt is one or more selected from the group consisting of LiCl, LiBr, CaBr2, Ca(NO3)2, LiNO3 and KNO3.

Abstract: A method for fault location to multi-terminal traveling wave in a direct current distribution line, which belongs to the field of power line fault ranging and location technology. The method includes a main site and a plurality of acquisition points installed into the distribution line and includes steps as follows. Step 1001: collecting and uploading a traveling wave signal by each of the acquisition points after a fault occurs in the line; step 1002: generating a fault record set; step 1003: computing the shortest paths from a central site to other sites and their lengths; step 1004: using expanded two-terminal traveling wave ranging principle for pairing computation; step 1005: converting positions of possible disturbance points into possible disturbance occurrence time points; step 1006: extrapolating from equal path lengths of the possible disturbance points to obtain disturbance time data; and step 1007: determining a final disturbance point.

Abstract: A controllable magnetic field-assisted finishing apparatus for an inner surface and a finishing method are provided. The apparatus includes a housing, ball screw mechanisms, a workpiece, a centering clamp, a connecting plate, a magnetic field generating device, a chuck clamp, a precise displacement platform and a base. The magnetic field generating device includes electromagnetic coils, coil connecting plates, a magnetic yoke, nuts, springs and bolts. The magnetic field generating device dynamically adjusts a distance from the magnetic yoke to the outer surface of the workpiece through the springs. The movement tracks of the magnetic finishing medium are controlled by the formed rotation of the magnetic field, the finishing action force dynamic-adjustment, the optimization of the machining form of the magnetic finishing medium in collaboration with the rotation of the chuck clamp and the feed movement of the precise displacement platform.

Abstract: A system for producing high-quality gas includes a heat carrier hoist, a coke feeder, a heat carrier heating furnace, a gas mixer, a high-temperature induced draft fan, a heat carrier storage tank, a dryer, a hopper, a concentrating solar collection pyrolysis-gasification reactor having a double-tube structure, a three-phase separator and a coke collecting bin. The system may use an adjustable concentrating solar collection technology in combination with a heat carrier circulation heating process, so as to effectively solve heat requirements of the waste pyrolysis and gasification process, reduce the waste material consumption caused by energy supply, and improve the effective utilization of raw materials.

Abstract: A method for fault location to single-terminal traveling wave includes steps as follows. Step (a): recording a waveform of a traveling wave signal of disturbance by a traveling wave device when a line disturbance occurs. Step (b): performing a phase mode transformation on the waveform recorded by the step (a), so as to obtain components of line mode and zero mode of a fault initial traveling wave, and performing a wavelet transform to decompose the components of the line mode to obtain singularities in the waveform of the traveling wave. Step (c): calculating a wavefront slope k of the components of the line mode of the fault initial traveling wave. Step (d): computing a preliminary fault distance D according to the slope k computed in the step (c). Step (e): confirming a fault point according to the preliminary fault distance and wavelet singularities of the components of the line mode. Step (f): end.

Abstract: A wheel hub motor for an electric vehicle includes eight sector-shaped through holes uniformly distributed in the circumference of a disc brake fixed to a shaft, and magnetic conductive ribs made of a magnetic conductive material arranged between two through holes. A stator core consists of nine square-C-shaped sub stator cores, each sub stator core surrounds two sides of the disc brake (6) and is fixed to a vehicle frame, adjacent sub stator cores are different by 30 degrees in a circumferential direction, a concentrated armature winding is wound around a yoke part at the middle portion of the sub stator core. A permanent magnet is fixed to a surface of an inner side of each sub stator core towards the disc brake, the brake caliper is fixed to the vehicle frame and is located at a position without the stator core in a circumferential direction.

Abstract: A magnetic field assisted vibratory finishing device for a minute structure and a finishing method is provided. The device includes a rotating shaft, a workpiece clamping device, a magnetic field generating device, a vibration assisting device, a three-axis precision displacement platform and a base. The magnetic field generating device includes a baffle plate, magnetic poles and a magnetic pole groove. The vibration assisting device includes a housing, guide fixing rods, a vibration motor, a vibration connecting plate, and compression springs. The workpiece clamping device clamps parts of structural shapes, and the frequency controller can control the motion mode of the magnetic field generating device during the finishing processing, thereby controlling the motion track of grinding material.

Abstract: An organic amine salt compounds of general formula An?[Bm+]p (I) is disclosed, wherein An? is a CO2-donating anion with a valence of ?n, wherein n=1, 2 or 3; each Bm+ comprises: ammonium ion, hydrazinium ion and/or organic amine B cation; wherein m = 1 ? - ? 10 ; 0 < p ? n m ; and wherein An? is one or more selected from a group consisting of following anions: (a) carbamate orcarbazate; (b) carbonate; (c) formate; (d) bicarbonate; (e) organic monocarbonate; (f) organic poly-carbamate; (g) orthoformate; or (h) organic poly-carbonate. The compound of general formula (I) has at least one of hydroxyalkyl group linked to N atom, i.e., has alkanolamine residue. They can be used as polyurethane foaming agent, and most of them can be used as polystyrene foaming agent or polyvinyl choride foaming agent.

Abstract: The present invention discloses an automatic high-shear low-pressure force-controlled grinding device for a complicated curved surface and a machining method thereof, which belong to the field of complicated curved surface grinding technologies of difficult-to-machine materials. The device comprises a base, columns, an industrial robot, an electrical spindle, a force-controlled floating tool holder, a workpiece chuck, a grinder plate, a six-dimensional force sensor, a rotary table, a triaxial precision displacement table, a safeguard hood, a safety door, and a pedestal. The grinder plate comprises a grinder plate substrate, a press plate, a lining plate, and an abrasive layer. Each module is effectively communicated, and a control system collects and processes signals as well as transmits commands to achieve automatic force-controlled grinding of the complicated curved surface.

Abstract: An electromagnetic clutch of a brushless control-by-wire centrifugal ball arm engagement device includes a brushless electromagnet, a thrust pressing disc, a driven inner-spline hub, a control-by-wire drive disc, a centrifugal ball arm hollow disc, centrifugal ball arm pins, centrifugal ball arms, centrifugal balls, a magnetic conductive force transmitting disk, a drive shaft; once the brushless electromagnet is energized, the centrifugal ball arms and the centrifugal balls each make a circular motion around the centrifugal ball arm pin outwardly along the smooth surface of the thrust pressing disc by the action of centrifugal force produced by them when rotating with high speed. The component of the centrifugal force in the direction of the central axis of the centrifugal ball arm hollow disc drives the thrust pressing disc to compress the outer-spline-groove steel sheets and the inner-spline-groove friction discs with each other, which makes the clutch engaged.