100results about How to "Stop the spread" patented technology

The application discloses a serological method for identifying Brucella A19-DeltaVirB12 vaccine immunized animals and infected animals, and belongs to the technical field of veterinary vaccine detection, comprising the step of identifying the antibodies of the serum by using the NH-AGID method. The method helps to perfect the animal Brucella A19-DeltaVirB12 vaccine prevention and control technical system, makes up for the short board that the A19-DeltaVirB12 vaccine immunized animals cannot be identified, and provides technical support for realizing the precise prevention and control of bovine brucellosis. The application of the method will accelerate the application of the Brucella A19-DeltaVirB12 vaccine to replace the traditional A19 vaccine, and opens a new milestone for the prevention and control of Brucella.

The utility model discloses a high-pressure sealing structure of high-temperature sterilization equipment for edible mushroom production in the field of high-pressure sealing, which comprises a sealing component, the sealing component comprises a sealing cover, the upper surface of the sealing cover is movably connected with a fixing bolt, and the outer surface of the sealing cover is fixedly connected with a first sealing ring; a second sealing ring is fixedly connected to the outer surface of the sealing cover, a spring column in the anti-leakage assembly is arranged, and when the second sealing ring extrudes the surface of a connecting pad, the spring column can eject a connecting plate upwards, so that the spring column adapts to size changes through elastic deformation of the spring column, and pressure on a sealing component is always kept; the sealing surfaces are tightly attached, so that the good sealing effect is maintained, meanwhile, pressure distribution can be automatically adjusted according to the actual conditions of the sealing surfaces, the problem that sealing is not tight due to the fact that local pressure is too high or too low is solved, and sealing reliability is improved.

This invention discloses an antioxidant porous TiAl alloy, the raw materials of which include: a mixed powder, nano-B4C, nano-NiO, and nano-SiO2. The mixed powder comprises TiH2 powder and aluminum powder; the Ti content in the mixed powder is 51-53 wt%; the weight ratio of nano-B4C, nano-NiO, and nano-SiO2 to the mixed powder is 2-3:0.5-1.5:2-3:100. This invention also discloses a method for preparing the above-mentioned antioxidant porous TiAl alloy, comprising the following steps: mixing TiH2 powder and aluminum powder to obtain a mixed powder, then adding nano-B4C, nano-NiO, and nano-SiO2 and mixing, pressing into shape, vacuum sintering, soaking in an alkaline solution, and washing with water to obtain the antioxidant porous TiAl alloy. This invention also discloses the application of the above-mentioned antioxidant porous TiAl alloy in filtering high-temperature flue gas. This invention exhibits excellent antioxidant and filtration performance.

The application discloses a logistics supply chain transportation delay risk intelligent early warning system and method, belongs to the technical field of logistics supply chain management, and is used for solving the problems that the existing logistics transportation delay prevention and control relies on manual experience, key node control is passive, and whole-process risk data is isolated; the system contains three modules of transportation capacity risk assessment, node risk control and transportation risk early warning, transportation capacity classification screening is completed by combining with the analytic hierarchy process through construction of driver hierarchical performance data archives and standardized transportation order system; the loading and unloading nodes are monitored in real time, and delay risks are quantified, and differentiated intervention is implemented; multi-link data is fused to account for comprehensive risks of whole-link and dynamically push early warning; the application forms a closed-loop prevention and control system of source screening-node control-whole-process early warning, can standardize transportation capacity evaluation processes, actively resolve node abnormalities, break through data barriers, effectively improves logistics transportation delay risk control capability and transportation timeliness stability, and is suitable for timeliness control needs of various logistics orders.

The application discloses a resistive switching memory structure and a manufacturing method thereof. The resistive switching memory structure comprises, from bottom to top, a bottom electrode, a resistive switching layer and a top electrode. The upper surface of the bottom electrode and the lower surface of the resistive switching layer are in Schottky contact, and the lower surface of the top electrode and the upper surface of the resistive switching layer are in Ohmic contact. The resistive switching layer is a single oxide film layer. The materials of the bottom electrode and the top electrode are the same metal nitride, and the atomic number ratio of metal elements to nitrogen elements in the top electrode is greater than that in the bottom electrode. The application can simplify the structure of the memory, reduce the process complexity and manufacturing cost.

The utility model discloses a transmission assembly of low-noise environment-friendly hoisting equipment, which belongs to the technical field of hoisting equipment and comprises a hoisting outer box, a hoisting inner box is arranged in the hoisting outer box, and a plurality of nonlinear rubber vibration isolators are embedded at the bottom of the inner wall of the hoisting outer box. The sides, away from the hoisting outer box, of the multiple nonlinear rubber vibration isolators are fixedly connected with the hoisting inner box, a hoisting rope is arranged in the hoisting inner box, and the hoisting rope penetrates through the bottom of the hoisting inner box and the bottom of the hoisting outer box and is movably connected with the hoisting inner box and the hoisting outer box. The hoisting outer box and the hoisting inner box are matched, a hollow interlayer is formed between the hoisting outer box and the hoisting inner box, sound transmission is effectively prevented, the multiple nonlinear rubber vibration isolators are connected with the hoisting inner box to form a suspension type isolation structure, and part of vibration transmission is reduced.

The application discloses a compression-torsion coupling mechanism and a phononic crystal damping device with adjustable band gap, and belongs to the technical field of phononic crystal damping. The compression-torsion coupling mechanism comprises two plastic elastic plates arranged oppositely, the two plastic elastic plates are connected through a plurality of connecting rods, the connecting rods are connected with the corresponding plastic elastic plates through spherical hinges at two ends, electromagnetic coils are arranged on opposite surfaces of the two plastic elastic plates, the two electromagnetic coils are respectively connected with power supplies, and holes matched with tubular target structures are arranged on the plastic elastic plates. The phononic crystal damping device with adjustable band gap comprises a plurality of sleeves, the plurality of sleeves are used for being regularly and intervalled on the tubular target structure, at least one compression-torsion coupling mechanism is arranged between the two sleeves, the compression-torsion coupling mechanism is convenient to design and manufacture, the installation spacing of the phononic crystal damping unit can be changed through remote and reversible electromagnetic driving, and therefore the effect of adjustable band gap is achieved, and the operation is simple.

This invention relates to the field of cable protection conduit technology, specifically a flame-retardant and impact-resistant protective conduit for communication and power cables. The conduit includes a flame-retardant structure comprising an outer tube layer, the inner wall of which is fitted with a heat-resistant outer tube. An impact-resistant protective structure is provided on the inner wall of the inner mounting layer, including a cable mounting bracket outer tube located on the inner wall of the inner mounting layer. One end of the outer tube layer has a conduit interface structure. This flame-retardant and impact-resistant protective conduit for communication and power cables exhibits significant flame-retardant effects, effectively preventing flame spread, avoiding pipe combustion and dripping, and effectively absorbing impacts from external collisions and compression. It can withstand various external impacts such as outdoor construction, vehicle collisions, and heavy object compression. Furthermore, it improves splicing and connection efficiency, is suitable for large-scale cable laying projects, and can significantly shorten the construction cycle.

This invention is a divisional application of Chinese invention patent application No. 202310608706.5, filed on May 28, 2023, entitled "Slow-Release Hydrogen Production Material Containing Nano-Silicon and Its Application in Aquatic Ecosystem Restoration". This invention discloses a slow-release hydrogen production material containing nano-silicon and its preparation method, belonging to the field of environmental protection technology. The invention involves sterilizing a 2-5% sodium alginate solution, cooling it to room temperature, adding 0.3-0.5% wt of nano-silicon to the sodium alginate solution, and stirring at 500-600 r / min at room temperature for 30-60 min to obtain a nano-silicon sodium alginate solution. The prepared nano-silicon sodium alginate solution is then added dropwise at a volume ratio of (1-5):1 to a 2-5% CaCl2 solution at a rate of 1 drop / second, and allowed to stand for 5-10 min to obtain the final product. The layered structure of this material allows the nano-silicon material to be uniformly distributed and stably produce hydrogen within the sphere.

The utility model relates to the technical field of battery detection, in particular to a battery vibration test transmission device, and adopts the technical scheme that the battery vibration test transmission device comprises a base, a placement table is mounted on the base, a protective cover is mounted on the base, the front end and the rear end of the protective cover adopt open structure design, a hole is formed in the protective cover, and a discharge mechanism is mounted on the protective cover. The discharging mechanism is used for discharging the combusted battery pack; a feeding mechanism is mounted on the placement table and is used for conveying a battery pack; the feeding mechanism comprises sliding rods, the sliding rods are fixedly connected through a connecting plate, a baffle is installed on the sliding rods through an inclined supporting plate, and the size of the baffle is matched with the size of the opening position of the protective cover. The device has the advantages that fire behavior isolation and rapid removal can be carried out on the burning battery pack, and the problems that an existing device cannot effectively block fire behavior spreading of the burning battery pack and is lack of a rapid removal mechanism are solved.

The utility model provides automatic fire cut exhaust system, relates to fire field, including water supply tank, the outer wall of water supply tank is fixedly connected with water supply motor, the outer wall of water supply tank is matched to be provided with acid mist purification tower, the outer wall of acid mist purification tower is provided with control cabinet, the outer wall of acid mist purification tower is fixedly connected with temperature control valve, in the utility model, when the workshop breaks out fire, this system can rely on the linkage mechanism of thermocouple and temperature control valve, and the exhaust motor power is automatically cut off and the valve is closed in the moment of detecting abnormal temperature, prevents the exhaust system from intensifying the fire spreading and smoke diffusion because of the chimney effect accurately, gains the precious time for personnel safety evacuation and fire rescue, reduces the security risk from the root, in addition, the system adopts the humanization design, only needs to connect the power and completes the basic parameter setting to put into operation, discards the complicated operation process, greatly promotes the use convenience, even if the non - professional personnel can also grasp the operation gist quickly.

The present application relates to the technical field of oxalic acid processing, and particularly relates to an oxalic acid material feeding and discharging device.The present application provides an oxalic acid material feeding and discharging device capable of preventing the diffusion of oxalic acid powder.The oxalic acid material feeding and discharging device comprises a mixing barrel, a discharging pipe connected to the bottom of the mixing barrel, a feeding frame connected to the top left side of the mixing barrel, a separation net connected to the inside of the feeding frame, a covering mechanism arranged on the upper right side of the feeding frame, and an absorption mechanism arranged between the top of the mixing barrel and the feeding frame.The oxalic acid is put into the feeding frame, and then the cover is closed, so that the diffusion of oxalic acid powder can be avoided when the oxalic acid is discharged, thereby improving the safety.

The invention provides a flame-retardant antistatic nylon fiber with a skin-core structure and a preparation method of the flame-retardant antistatic nylon fiber, and belongs to the technical field of nylon fibers. The flame-retardant antistatic nylon fiber comprises an antistatic nylon skin layer and a flame-retardant nylon core layer, the outer surface of the flame-retardant nylon core layer is coated with the antistatic nylon skin layer, the antistatic nylon skin layer comprises a nylon 6 matrix and an antistatic agent, and the antistatic agent is aniline modified zirconium phosphate; wherein the aniline modified zirconium phosphate is obtained by carrying out in-situ polymerization on aniline monomers between stripped zirconium phosphate layers. The flame-retardant antistatic nylon fiber is obtained through sheath-core composite melt spinning. According to the invention, the antistatic agent and the flame retardant are efficiently and stably introduced into the nylon matrix, and the synergistic effect of the antistatic agent and the flame retardant is realized, so that the fiber has better spinnability and mechanical property, and meanwhile, the long-term effect and durability of the function are ensured.

The utility model discloses a kind of fireproof light power cable of rat and termite prevention, including conductor, the outside of the conductor is equipped with shielding layer, the outside of the shielding layer is equipped with insulating layer, the outside of the insulating layer is equipped with inner protective layer, the outside of the inner protective layer is equipped with physical protection layer, the outside of the physical protection layer is equipped with protective net layer, in the utility model, the power cable, by inner protective layer inner layer elastic memory resistance layer hardens and releases chlorpyrifos when receiving ≥5N bite pressure, outer layer honeycomb metal-ceramic composite layer improves bite resistance strength;Physical protection layer forms barrier with material hardness;Protective net layer can release medicament, and the defense capability of rat and termite bite is improved compared with traditional cable by multilayer protection;And insulating layer uses high-temperature resistant material to guarantee fireproof basis;Inner protective layer outer layer honeycomb metal-ceramic composite layer can form fireproof barrier when meeting fire.These structures cooperate and improve the fire resistance in fire situation compared with traditional cable.

The present disclosure relates to a display device and a method for manufacturing a display device. The display device can include a substrate including a display area and a bending area; a buffer layer disposed on the substrate; a first dummy pattern disposed on the buffer layer in the bending area; a first insulating layer disposed on the buffer layer, the first insulating layer exposing an upper surface of the first dummy pattern; a second insulating layer disposed on the first insulating layer, the second insulating layer having an opening exposing the upper surface of the first dummy pattern; a second dummy pattern disposed on the upper surface of the first dummy pattern exposed through the opening; and a transmission line disposed on the second dummy pattern.

This invention discloses a method for refining primary silicon in Al-Si alloys through synergistic modification with nano-ceramics based on laser additive manufacturing. The method involves uniformly mixing Al-Si alloy powder with TiB2 and Al2O3 nano-ceramics using a ball mill under inert gas protection to obtain a ceramic-reinforced nano-Al-Si alloy composite powder. This nano-ceramic-modified Al-Si alloy powder is then melted and solidified layer by layer using a laser powder bed melting and forming equipment to create the desired target part. In this method, during the solidification of the nano-ceramic-reinforced Al-Si alloy melt, Al2O3 nanoparticles, due to their similarity to the Si crystal structure and the existence of a good interfacial coherence relationship, act as heterogeneous nucleation sites for primary silicon, increasing the nucleation rate and refining the size of primary silicon. TiB2 nanoparticles, distributed at the solid-liquid interface, can to a certain extent prevent the diffusion and aggregation of Si atoms into Si-Si atom clusters, thereby inhibiting the growth of the primary silicon phase, promoting the regularization of the primary silicon morphology and refining its size, and effectively reducing matrix grain size, significantly improving the mechanical properties of the Al-Si alloy.

The utility model discloses a chemical adding device and a sewage treatment system, and relates to the technical field of sewage treatment, the chemical adding device comprises a chemical adding bin, an unpacking assembly and a water film dustproof assembly, the chemical adding bin comprises a chemical carrying area and a dust removal pipe mounting area, and the chemical carrying area is arranged at the bottom of the dust removal pipe mounting area and communicates with the dust removal pipe mounting area; the unpacking assembly is arranged in the medicine carrying area and used for breaking medicine bags and enabling medicine to flow into the medicine carrying area. The water film dust prevention assembly comprises a water film dust removal pipe, the water film dust removal pipe is arranged on the inner wall of the dust removal pipe installation area and arranged in the circumferential direction of the dust removal pipe installation area, a water outlet used for discharging water is formed in the side wall of the water film dust removal pipe, and water in the water film dust removal pipe can be sprayed to the peripheral side face of the medicine bag through the water outlet in the medicine adding process; and a water film is formed to prevent medicine dust from diffusing. By additionally arranging the water film dustproof assembly, diffusion of medicine dust in the medicine adding process can be effectively reduced, and therefore harm of the medicine dust to operators and pollution of the medicine dust to the surrounding environment are reduced.

The application relates to an injection molding material of a remote controller shell, a preparation method and an injection molding process, and belongs to the technical field of plastic processing. The injection molding material of the remote controller shell comprises the following raw materials in parts by weight: 60-70 parts of ABS, 10-15 parts of modified rice husk powder, 3-4 parts of an ABS-g-MAH compatilizer, 8-10 parts of modified basalt fiber, 0.6-1.0 parts of an ultradispersion lubricant, 0.3-0.5 parts of an antioxidant and 3-5 parts of an MBS toughening agent. The application introduces a polydopamine layer on the surface of the rice husk powder by modifying the rice husk powder, the polydopamine has rich benzene rings, can form a pi-pi conjugation effect between the benzene rings in the ABS, and makes the molecular chains of the ABS entangled on the surface of the modified rice husk powder, thereby enhancing the dispersity of the modified rice husk powder in the ABS. In addition, the polydopamine is black in color, the rice husk powder coated with the polydopamine is also black, and the color difference between the remote controller shell after adding the rice husk powder and the traditional black color is avoided.

The application discloses a kind of Gliocephalotrichum simmonsii and application thereof, the strain number of the Gliocephalotrichum simmonsii (Gliocephalotrichum simmonsii) is JSAFC 2056, and is preserved in China Microorganism Culture Collection Center on September 23, 2024, and the preservation number is CGMCC No.41562.The biocontrol agent of the application provided can significantly inhibit the survival activity of Anomala cuprea, and the survival activity of Anomala cuprea can be reduced to 0 after 28 days of treatment, and the biocontrol agent is environmentally friendly, non-toxic and harmless.The preparation method of the biocontrol agent of the application provided is simple, the culture requirement is low, and has good application prospect.

This invention provides a solar cell, its fabrication process, a tandem solar cell, and a photovoltaic module. The fabrication process of the solar cell includes: providing a cell substrate; printing a conductive material onto the cell substrate; and curing the conductive material to form initial grid lines. The conductive material includes bismuth-based lead-free glass; the conductive material also includes copper powder and nickel powder; the mass ratio of copper powder to nickel powder is 80~99.5:0.5~20, and the copper powder includes flake-shaped copper powder and spherical copper powder. In the fabrication process of this invention, the conductive material, through a ternary synergistic system of "copper-nickel-glass" and a dual-morphology copper powder composite design, achieves multiple effects such as suppressing copper diffusion and oxidation and improving adhesion under an air-sintering atmosphere, thereby improving the fill factor and photoelectric conversion efficiency of the solar cell.

The utility model discloses a kind of automobile flame-retardant seat cushions, it includes pad body surface layer, the pad body surface layer upper side is connected with backrest, the backrest upper side is connected with headrest, the backrest both sides are symmetrically connected with side pad, the side pad one side is connected with first telescopic belt, the side pad one side is connected with second telescopic belt. Through the above structure, pad body surface layer adopts fireproof fabric, its inside is provided with glass fibre layer, can constitute double flame-retardant barrier, can effectively block flame spread and heat transfer, substantially reduce the risk of seat combustion when vehicle fire, by magic tape wool surface, the cooperation of magic tape prickle surface, collocation antiskid pad, make seat cushion installation firm and dismounting convenient, seat cushion inside is provided with honeycomb layer, can provide excellent breathability and buffering, headrest is connected with neck pillow between backrest, pad body surface layer upper side is provided with backrest, side pad and other ergonomic support, can effectively alleviate fatigue of long time driving, improve ride comfort.

This utility model relates to the field of heat dissipation guide plate technology, and discloses a low-voltage cabinet ventilation and heat dissipation guide plate, including a heat dissipation frame. A heat dissipation component is fixedly connected inside the heat dissipation frame to absorb hot air inside the cabinet. Grooves are provided on both sides of the front of the heat dissipation frame. A guide plate body is slidably connected inside the heat dissipation frame. Insertion plates are fixedly connected to both sides of the guide plate body. A support plate is fixedly connected to the opposite side of the insertion plates. A connecting shaft is fixedly connected inside the support plate, and a connecting sleeve is slidably connected to the outside of the connecting shaft. This utility model facilitates the disassembly and assembly of the guide plate body, making cleaning and maintenance convenient, improving the ease of use of the equipment. It also effectively improves heat dissipation performance and equipment reliability, ensuring stable operation of the equipment under different working environments.

The application discloses a kitchen door based on automatic control of smoke concentration, a system and a control method; the kitchen door based on automatic control of smoke concentration comprises a door frame, a fixed door fixedly connected with the door frame and a sliding door slidingly connected with the door frame; the inside of the door frame is provided with a driving mechanism for driving the sliding door to slide; the kitchen door further comprises a smoke sensor for detecting smoke concentration in the kitchen; and a controller is used for acquiring smoke concentration data detected by the smoke sensor; by integrating the smoke sensor and the controller, the kitchen door based on automatic control of smoke concentration is realized, and the opening and closing state of the sliding door can be automatically adjusted; when the smoke concentration detected by the smoke sensor exceeds the threshold value set by the controller, the controller instructs the driving mechanism to act, the sliding door is driven to move to the closed position, and the smoke in the kitchen is effectively prevented from spreading to the residential area.

The application relates to application of an organic sulfonate molecule in a perovskite solar cell and a normal perovskite solar cell and a preparation method thereof, and belongs to the technical field of perovskite solar cell preparation. + The application adopts different organic sulfonate molecules to dope a hole transport layer (HTL), and through synergistic effect of anions and cations in the organic sulfonate molecules, Li 4-tert-butylpyridine (tBP) and halogen ions are fixed, defects at a perovskite / HTL interface are passivated, the HTL and the interface non-radiative recombination loss are simultaneously stabilized, controllable preparation of a high-efficiency and stable perovskite solar cell is realized, and a foundation is laid for commercial application of perovskite photovoltaic technology.

The present application relates to a kind of drag type coke environmental protection quantitative car loading equipment and method, comprising: steel structure frame, steel structure frame is sequentially arranged from top to bottom the head of belt conveyor, bunker, cut off material arc-shaped gate, telescopic chute, swing anti-crushing gate, the end of the gate of swing anti-crushing gate is equipped with cut-off gate, the lower part of steel structure frame is equipped with the dustproof cover of closed dust removal device, the both ends of closed dustproof cover are equipped with automatic car door and automatic car door, the ground in closed dustproof cover is sequentially equipped with vehicle dragging device and ground scale from top to bottom.The present application is directed to the characteristics of fragile and poor flowability of coke, cancels the weighing bin, adopts the floor scale weighing that can drag vehicle to move.A control coke falling arc-shaped gate is arranged between telescopic chute and storage bunker, a inclined gate is arranged at the outlet of telescopic chute, and a cut-off gate is arranged at the end of the inclined plate of inclined gate, so as to reduce the coke crushing.At the same time, fence and dust collection equipment are arranged to protect the environment.

The application discloses an electric energy metering box, and relates to the technical field of power distribution equipment. The box body cooperates with a box door to enclose a closed cavity. A fire sensing device and an air pressure sensor are integrated in the cavity. Telescopic isolation components are arranged on the box door corresponding to each electrical element. Independent fire extinguishing components and pneumatic driving components are matched. A high-pressure gas source device and a main pipeline assembly are simultaneously carried. When a fire occurs, the closed cavity simultaneously carries out oxygen reduction by air extraction. The high-pressure gas source drives corresponding movable covers to extend, individually covering the electrical element on fire. Then, the independent fire extinguishing components spray fire extinguishing agents at fixed points to achieve single-point accurate fire extinguishing. After the fire is eliminated, the structure automatically resets after pressure relief. The application can block the spread of fire, avoid the influence on the intact electrical circuit, and effectively reduce the loss of electrical fire, thereby improving the safety of power distribution operation and the stability of power supply.

The utility model discloses a booster-level flame-retardant low-intermodulation feeder line, and relates to the technical field of cables. The booster-level flame-retardant low-intermodulation feeder line comprises an inner conductor, an insulating layer, an outer conductor and a sheath which are coaxially arranged from inside to outside, the outer conductor is a spiral corrugated metal tube, the insulating layer is made of low-density polytetrafluoroethylene with a fibrous microporous structure, and the sheath is made of booster-level flame-retardant fluorinated ethylene propylene; the booster-level flame-retardant low-intermodulation feeder line provided by the utility model has the characteristics of high temperature resistance, high flame retardance, high shielding, low loss, low passive intermodulation and super-flexible bending, is suitable for booster-level cables or cable assemblies of a UL system, and is particularly suitable for interlayers of ceilings and high-flame-retardant safe application occasions of super-flexible wiring connection.

The application relates to the technical field of tires, in particular to a radial aviation tire, which comprises a carcass, a belt layer which is pasted on the carcass along the circumferential direction of the tire, the belt layer comprising a basic layer, a stress transition layer and a stress clamping layer, the widths of the basic layer, the stress transition layer and the stress clamping layer gradually decrease, the cords of the basic layer, the stress transition layer and the stress clamping layer are all wound along the circumferential direction of the tire, a tire turning rubber sheet which is pasted on the stress clamping layer and extends along the circumferential direction of the tire, a protective layer which is pasted on the tire turning rubber sheet, the cords of the protective layer extend along the circumferential direction of the tire in an S shape, and a tread which is fixed on the protective layer. The cords arranged at 0 degrees of the belt layer can make the tire realize the same load bearing capacity with less material when bearing the circumferential load, effectively reducing the tire weight, and the S-shaped arrangement of the cords of the protective layer can effectively prevent the straight line from spreading.

The utility model relates to the technical field of engine cover plate, especially relates to a dustproof and waterproof sealed engine cover plate, including first fixed plate and second fixed plate, the first fixed plate and second fixed plate between joint sealing assembly fixedly connected have, the sealing assembly upper end sleeve joint has the protection assembly, protection assembly upper end four corners all threadedly connected have bolt. The utility model discloses a dustproof and waterproof sealed engine cover plate, along with bolt tightening, protection assembly presses sealing assembly, and sealing washer is extruded and produces elastic deformation, and tightly fits the lower end surface of aluminium alloy shell, forms an elastic barrier, and the dust and moisture of outside are blocked outside the edge of cover plate, simultaneously, the sealing ring is extruded by the fire -retardant inner shell, fills the gap between sealing washer and fire -retardant inner shell, constructs the second sealed defense line, effectively avoids the trouble that engine causes dust accumulation to lead to poor heat dissipation, causes circuit short circuit because of water vapor erosion, prolongs the maintenance cycle and the service life of engine.

This application provides a composite current collector and its preparation method, a negative electrode, and a secondary battery. The composite current collector includes a substrate layer, a transition layer disposed on at least one side of the substrate layer, and a conductive layer disposed on the transition layer. The substrate layer is made of one or more of copper-nickel alloy, copper-tin alloy, and iron-nickel alloy. The elements contained in the transition layer are not entirely the same as those contained in the substrate layer. An elemental gradient diffusion region exists at the interface between the substrate layer and the transition layer. Within this region, the elements contained in the substrate layer and the transition layer diffuse into each other, and their concentrations are distributed in a gradient along the thickness direction. The composite current collector provided by this application has improved interfacial bonding.