3234 results about "Heat stability" patented technology

The invention discloses a 3D printing layered honeycomb sandwich panel and a processing method thereof. The processing method comprises the steps that a digital forming platform is constructed, process parameters are initialized, a functional interface layer is laid on a printing substrate in advance, a three-dimensional model is generated, and the printing substrate is divided into a plurality of gradient areas; collaborative printing of a lower panel structure is executed, and a composite panel base body is formed by adopting a multi-nozzle alternate deposition process; according to the characteristics of the divided gradient areas, honeycomb units are formed layer by layer by dynamically controlling printing rheological parameters, and a gradient honeycomb core layer is constructed; the cooperative growth of the upper panel and the gradient honeycomb core layer is realized by adopting a rotary incongruous printing strategy; the performance of the core layer material is regulated and controlled through a multi-stage heat treatment process, and the functional interface layer is activated to obtain the honeycomb sandwich panel; according to the honeycomb sandwich board, the mechanical property customized distribution of the honeycomb core layer is realized, the surface-core interface bonding strength is improved by combining the directional activation mechanism of the micro interlocking structure and the functional interface layer, and the honeycomb sandwich board with high mechanical property and thermal stability is provided.

The invention provides an intelligent harmonic dynamic compensation method and system for a data center. According to the method, server heat source surface temperature field distribution is monitored in real time through a distributed optical fiber temperature measurement array, and a dynamic impedance spectrum is generated; when the temperature gradient exceeds the flash evaporation critical value of the fluorinated cooling liquid, an active filter is activated to carry out dynamic impedance matching compensation on high-frequency harmonic current in the liquid cooling tank cabinet, and a pulse width modulation control signal of a circulating pump is generated; the compensation power of the filter and the turbulence intensity of the cooling liquid are synchronously adjusted by analyzing the coupling relation between the flowing vortex intensity of the cooling liquid and the dielectric polarization loss; when phase mismatch of a temperature field is caused by heat dissipation of multiple heat sources, a multi-band compensation strategy is reconstructed by utilizing frequency domain characteristics of a pulse width modulation signal and a compensation power historical value, and a cooling liquid branch flow distribution ratio and a filter frequency response curve are cooperatively adjusted. According to the technical scheme, the thermal stability and the electrical safety of the data center cooling machine room are improved.

The present invention provides a composition, particularly a composition for an organic electroluminescent device, the composition comprising a first compound having a structure represented by formula (I-1) or (I-2) and a second compound having a structure represented by formula (II). The composition is easy to prepare and good in thermal stability, meanwhile, the compound can adjust the stability of the material, and finally it is ensured that the photoelectric property of a device prepared from the compound is obviously improved. # imgabs0 #

The invention discloses a high-temperature superconducting coil structure, and relates to the technical field of superconducting magnets, and the main points of the technical scheme are that the high-temperature superconducting coil structure comprises a solenoid superconducting coil which is arranged in a layer winding manner and is internally provided with a first cooling channel arranged along the axis direction of a wire; the shunt bypasses are arranged on the solenoid superconducting coil at intervals, and second cooling channels are arranged in the shunt bypasses; wherein the shunt bypass and the solenoid superconducting coil are connected in a lap joint mode to form a connector, and at least one longitudinal cooling hole for communicating the first cooling channel with the second cooling channel is formed in the connector. While the inherent thermal stability and safety of the magnet are improved, the number of coil joints is greatly reduced, and heat generated by the joints is reduced; the superconducting magnet is divided into multiple sections by the shunt bypasses which are connected in parallel, and the shunt bypasses serve as a refrigerant inlet and outlet of the magnet and also serve as a rapid energy release and energy transfer loop during magnet quenching protection, so that the cooling efficiency of the magnet is improved, and the energy release speed of a magnet quenching section is increased.

The invention relates to the technical field of film packaging, in particular to a PA-EVOH multi-layer co-extrusion film, a preparation method thereof and a composite film. The PA-EVOH multi-layer co-extrusion film comprises a first functional surface layer, a first secondary surface layer, a core layer, a second secondary surface layer and a second functional surface layer, the thickness of the core layer is 13%-40% of the total thickness of the film layer, the melting point of the adopted PA resin is 215-225 DEG C, the melting point of the EVOH resin is 164-183 DEG C, and the ethylene content is 32-44 mol%. The PA-EVOH multi-layer co-extrusion film and the composite film thereof have high barrier property and thermal stability, and good transparency and apparent quality, and can be used for pasteurization or poaching sterilization food packaging. The invention further provides a preparation method which is used for manufacturing the PA-EVOH multi-layer co-extrusion film, the film layer structure and the film layer thickness proportion are optimized, and better physical comprehensive performance and processing performance are achieved.

The invention belongs to the technical field of application of brake materials for brake pads, and particularly discloses a friction material for a phase change heat storage composite brake pad, which comprises Cu powder, Cr powder, V powder, CuAlMn particles, graphene powder and graphite powder in a mass ratio of (40-60): (10-25): (0.1-1.5): (10-30): (0.5-1.5): (4-6). The friction material for the brake pad has the beneficial effects that the prepared friction material for the brake pad is low in friction coefficient, good in wear resistance and good in heat fading resistance, and the service life is prolonged; cu is used as a matrix, and Cr and V are used as reinforced matrix components, so that the material plays an important role in the overall strength and wear resistance of the material for the brake pad; the CuAlMn particles are adopted, so that unstable friction coefficient and brake failure caused by over-high temperature of the friction material for the brake pad under the high-temperature condition are effectively relieved; graphene and graphite are used as lubricating materials, so that the friction coefficient is effectively reduced and stabilized, and the thermal stability is improved.

The invention discloses a ship heat exchanger heat transfer performance simulation method, particularly relates to the field of heat transfer, and comprises the steps of multi-source data acquisition, characteristic parameter calculation, heat transfer stability diagnosis, comprehensive heat transfer degradation evaluation, structure reliability prediction and system efficiency comprehensive evaluation. Multi-dimensional data synchronous acquisition is realized through a multi-source sensor network, a dynamic coupling analysis model is constructed to accurately calculate the heat transfer stability and the comprehensive degradation index, a three-level early warning mechanism is established to improve the state evaluation accuracy, turbulence attenuation characteristics and vibration data are fused to predict the structural reliability, and the reliability of the system is improved. And closed-loop management and control is formed by combining an efficiency index triple evaluation system, so that the spanning from single alarm to preventive maintenance is realized, the health management capability of the system is comprehensively enhanced, and full-life-cycle dynamic optimization support is provided for the ship heat exchanger.

The invention provides a permafrost region ventilation pipe foundation design method based on a heat balance principle, and aims to keep heat balance of permafrost on the lower portion of a foundation and ensure long-term heat stability of the foundation. According to the method, meteorological data, soil physical parameters and permafrost upper limit and ground temperature distribution information are collected so as to evaluate whether additional protection measures are needed or not and determine the burying height of the ventilation pipe foundation. And based on the selected ventilation pipe configuration, the air speed in the pipe is calculated by using a corresponding air speed calculation formula, and the convective heat transfer coefficient is determined accordingly. And determining the diameter of the pipeline by combining the convective heat transfer coefficient and the economical efficiency. And the cooling radius and the optimal operation mode of the ventilation pipe foundation are further determined, so that heat balance at the bottom of the foundation is ensured, and permafrost at the lower part of the foundation is effectively protected. The design method is simple, convenient, rapid and accurate, and has important engineering application value and wide applicability.

The present invention comprises Magnetic Tunnel Junctions and Bit-Patterned Media with a warped geometry with the purpose of attaining large thermal stability factors and dramatically increasing the scalability of the magnetic bits while still allowing the reduction of switching current density and switching magnetic field, and also increasing switching speed. The warped shape allows providing thermal stability to the bits through dynamic exchange energy barrier and also by providing additional net magnetic anisotropy through shape-induced reduction of the demagnetization field. The dynamic exchange energy barrier in turn allows engineering the damping torque and the free-layer's magnetic parameters to a much larger extent than the current planar technology. It also allows much faster magnetic-field-induced switching of patterned bits than it is possible with current hard disk drive technology, through the use of precession torque instead of conventional damping torque.

The invention provides a preparation method of an hourglass type covalent organic framework (COF) composite membrane, and belongs to the field of gas membrane separation. According to the method, covalent organic framework nanosheets with different pore diameters and charge characteristics are utilized to construct the COF composite membrane with a unique hourglass structure through a vacuum-assisted layer-by-layer assembly technology, so that precise regulation and control on H2 and CO2 gas transmission behaviors are realized, and the prepared composite membrane shows remarkable H2 / CO2 separation selectivity and high permeation flux, and has a good application prospect. The chemical stability, the thermal stability and the mechanical flexibility are excellent. The invention provides a novel solution for efficient gas separation and energy storage application.

The invention discloses a server liquid cooling cabinet group heat dissipation system with phase change energy storage, which comprises two linear array type server liquid cooling cabinet groups, two cooling capacity distribution units, two heat pipe air conditioner all-in-one machines, a multi-channel cold liquid distributor, a multi-channel hot liquid backflow device and the like, the all-in-one machine comprises a heat pipe natural cold source refrigerating loop and a compressor mechanical refrigerating loop, the two refrigerating loops independently or jointly provide an outdoor cold source, heat of all the liquid cooling cabinets is transmitted to the all-in-one machine in the cold capacity distribution unit, and therefore the heat is transmitted out of the machine room. A phase change energy storage flow channel is preferably arranged on the primary side of the intermediate heat exchanger in parallel, cold storage and buffering are achieved by switching a channel, a cold storage and cold release intelligent control strategy based on a lag temperature difference threshold value is constructed, a main cold source linkage and cold source switching smooth transition mechanism is achieved, the thermal stability, operation continuity and response capacity of the system are improved, and the system reliability is improved. The liquid cooling heat dissipation device is suitable for data center liquid cooling heat dissipation scenes with high heat density, high energy efficiency and high reliability requirements.

The invention belongs to the technical field of dielectric materials, and particularly relates to a dielectric material based on polybenzocyclobutene as well as a preparation method and application of the dielectric material. According to the multi-benzocyclobutene-based dielectric material provided by the invention, different halogenated hydrocarbon, olefin and other raw materials are used, and on the basis of containing more than two benzocyclobutene groups, a specific group can be introduced into a connecting group so as to improve the dielectric property and thermal stability of the material; meanwhile, specific groups can be introduced into R2 and R3 through secondary Heck reaction to further improve the dielectric property and thermal stability of the material, so that the dielectric material with excellent comprehensive properties such as dielectric property and thermal stability is provided, and the technical problem of lack of dielectric materials for high-frequency and high-speed printed circuit boards (PCBs) in the prior art can be solved.

The invention discloses a PA6 nylon composite material for a high-temperature-resistant filter screen and a preparation method of the PA6 nylon composite material, and relates to the technical field of composite materials. The invention discloses a PA6 nylon composite material for a high-temperature-resistant filter screen. The nylon material is prepared from the following raw materials in parts by weight: 60 to 80 parts of modified PA6 nylon, 10 to 20 parts of modified glass fiber, 2 to 5 parts of montmorillonite, 0.3 to 0.8 part of antioxidant 1010, 0.2 to 0.6 part of stearic acid, 0.5 to 1.0 part of ethoxylated fatty amine, 1 to 3 parts of nano titanium dioxide, 1 to 3 parts of polytetrafluoroethylene micro powder, 3 to 8 parts of aluminum hydroxide, 0.5 to 1.5 parts of chitosan, 1 to 3 parts of hyperbranched polyamide and 0.5 to 1.5 parts of urea-formaldehyde resin coated epoxy resin microcapsules. And 0.3 to 0.8 part of sodium polyacrylate. The PA6 nylon composite material for the high-temperature-resistant filter screen has remarkable advantages. The material disclosed by the invention is high in mechanical property, good in thermal stability and stable in size at high temperature; the self-cleaning, antibacterial and antistatic functions are realized, and the filtering efficiency is high; chemical corrosion resistance, wear resistance and low water absorption are achieved; part of the raw materials can be recycled, the environmental protection concept is met, and the use requirement of the high-temperature-resistant filter screen in a complex environment can be met.

The invention discloses an all-season hot rod device and a permafrost stability maintenance method, and belongs to the technical field of permafrost protection.The all-season hot rod device comprises a hot rod unit and a refrigeration unit, the hot rod unit is sequentially divided into a condensation section, a heat insulation section and an evaporation section from top to bottom, and the condensation section is arranged above the ground surface; the heat insulation section is arranged in a permafrost season activity layer, the evaporation section is arranged in a permafrost layer, and a gaseous heat-carrying agent on the lower portion of the evaporation section is injected into the upper condensation section through an ejector in the heat insulation section; the refrigeration unit is arranged at the top of the condensation section and can absorb heat of the condensation section and release the heat into the atmosphere; the operation of the hot rod unit and the refrigeration unit is controlled according to the permafrost temperature. The heat rod unit and the refrigeration unit are combined, cold can be continuously conveyed to permafrost all year round, and the heat stability of permafrost engineering is maintained; and meanwhile, the device has the advantages of zero energy consumption, efficient heat transfer, convenience in transportation and installation, is reliable in operation, and can achieve the dual purposes of permafrost protection, energy conservation and efficiency improvement.

The invention provides a DOPO-HQ-based flame retardant, a preparation method and application thereof, a flame-retardant anti-dripping PET composite material and preparation thereof, and belongs to the technical field of flame retardants. The DOPO-HQ-based flame retardant provided by the invention contains an efficient phosphorus-based flame retardant DOPO structure, so that the composite material can be endowed with efficient flame-retardant self-extinguishing performance; besides, the DOPO-HQ-based flame retardant contains a triazine structure, is high in thermal stability and has excellent high-temperature carbonization capacity, so that a large number of carbon layers are generated in the combustion process of the composite material and cover the surface of a base material, and the effects of molten drop resistance and smoke suppression are achieved. The thermal performance of the flame-retardant PET composite material prepared from the DOPO-HQ-based flame retardant is similar to that of pure PET, and the flame-retardant PET composite material has the characteristics of high flame-retardant efficiency, no halogen, no molten drop, low smoke release amount and the like under the condition of a small addition amount (2-8wt%) (the current commercially available flame-retardant anti-molten drop addition amount is greater than or equal to 15wt%).

The invention discloses a pure smelting method for nickel-based superalloy, which relates to the technical field of metal smelting and comprises the following steps: (1) screening high-purity raw materials; (2) selecting a vacuum induction melting furnace and carrying out vacuumizing treatment; (3) sequentially adding the pretreated raw materials into a vacuum induction melting furnace, and heating and melting the raw materials; (4) carrying out electromagnetic stirring; (5) preparing special electroslag, and drying and crushing the electroslag; and (6) casting the alloy liquid subjected to vacuum melting into a consumable electrode, inserting the consumable electrode into the slag of the electroslag remelting furnace, and electrifying. According to the design scheme, impurities in the nickel-based superalloy are effectively removed, the purity and uniformity of the alloy are improved, the mechanical property and thermal stability of the alloy are improved, the service life is prolonged, and a better purification effect is achieved.

The invention provides a polysilazane green special refractory ceramic coating and a preparation method thereof, and belongs to the field of ceramic coatings. The ternary core material composed of titanium carbide, zirconium boride and silicon nitride provides high hardness, oxidation resistance, thermal shock resistance and excellent thermal stability; the silicon dioxide-aluminum oxide composite shell layer remarkably improves the oxidation resistance and reliability of the coating through the synergistic oxidation resistance and crack self-repairing function; the multi-metal oxygen cluster network endows the coating with excellent electrical conductivity, thermal conductivity and corrosion resistance; the intercalated montmorillonite enhances the crack resistance and oxidation resistance through a layered structure and embedded active ions; and the boron nitride coated vanadium carbide particles provide lubricity, oxidation resistance and wear resistance. Through collaborative optimization of multiple components, the comprehensive performance of the coating is comprehensively improved in the aspects of oxidation resistance, thermal conductivity, interface stability, high-temperature performance, mechanical performance and the like, so that the coating shows excellent long-term stability and functionality in an extreme environment.

The invention discloses a preparation method of a high-homogeneity and high-stability copper target material, which comprises the following steps of: 1, cutting off a riser of a high-purity copper cast ingot, and turning to obtain a pretreated high-purity copper cast ingot; secondly, the pretreated high-purity copper ingot is heated and subjected to heat preservation in a furnace and then forged to obtain a forged copper blank; thirdly, the forged copper blank is subjected to room-temperature circumferential rolling treatment, and a rolled copper blank is obtained; fourthly, the rolled copper blank is subjected to two-stage annealing heat treatment, and a copper target blank is obtained; and 5, machining, cleaning and packaging to obtain the high-homogeneity and high-stability copper target material. According to the method, the high-purity copper cast ingot is sequentially subjected to pretreatment, forging, room-temperature circumferential rolling, two-stage annealing, machining, cleaning and packaging, preparation of the high-quality copper target material which is uniform in structure, controllable in crystal orientation and excellent in heat stability is achieved, the sputter coating quality is improved, and the method is easy to operate, high in controllability, high in production efficiency and suitable for industrial production. Meanwhile, raw materials and production cost are saved, and the method is suitable for large-scale popularization and application.

The utility model discloses an ultra-high manganese steel jaw plate inlaid with alloy bars, which comprises a jaw plate body, a plurality of slots are arranged in the jaw plate body, and reinforcing components are arranged in the slots. The reinforcing assembly comprises an alloy bar body and an insertion rod. The alloy bar bodies are connected into a whole, the alloy bar bodies are made of tungsten alloy bars and have high hardness, corrosion resistance and thermal stability, the strength of the jaw plate body is improved, and the service life of the jaw plate body is prolonged; according to the jaw plate, through the arrangement of the T-shaped protruding blocks and the bolts, the T-shaped protruding blocks below the jaw plate body are aligned with the T-shaped grooves in the mounting plate, the T-shaped protruding blocks are clamped into the T-shaped grooves, and therefore primary mounting of the jaw plate body is completed, the first screw holes are aligned with the second screw holes, the jaw plate body can be fixedly mounted on the mounting plate through the bolts, and mounting is easy and convenient.

The invention relates to a preparation method of a polyurethane-based flexible phase-change material and a battery heat management device. Polyethylene glycol is used as a phase-change material, and adipic dihydrazide (ADH) and 4, 4 '-diphenyltetracarboxylic dianhydride (ADH) are integrated at a condensation end of a heat pipe; at least one of 4, 4 '-diaminobenzanilide (DABA) is used as a cross-linking agent, and at least one of HMDI or IPDI is used as a chain extender to prepare the polyurethane-based flexible phase change material with enthalpy value, flexible rigidity and appropriate phase change temperature. The material not only has excellent mechanical strength and thermal stability, but also has healing property, recoverability and shape memory function. The polyurethane-based flexible phase change material serves as an energy storage film and forms a sealing structure with the condensation end through mechanical pressing. When the temperature rises, the energy storage film B1 absorbs heat and expands, the contact area with the outside is increased, the heat dissipation power is improved, and the heat dissipation efficiency and the heat load management capacity are remarkably improved by maximizing the heat transfer area and utilizing the high latent heat characteristic.

The present application discloses a composite separator, a preparation method therefor and a use thereof. The composite separator comprises a polyolefin separator, an adhesive layer coated on one or both sides of the polyolefin separator, and a cellulose film covering the surface of the adhesive layer, wherein the pore diameter of the cellulose film is greater than that of the polyolefin separator. According to the composite separator, the strength and thermal stability of a traditional separator can be improved, and the requirements of liquid absorption and retention are met, so that the performance and the cycle life of an energy storage device are improved.

The invention discloses a halogen-free flame-retardant reinforced PBT (polybutylene terephthalate) composition as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The halogen-free flame-retardant reinforced PBT composition comprises polybutylene terephthalate, a halogen-free flame retardant, a melamine flame-retardant synergist, glass fibers, a phenol amide metal deactivator, a free radical trapping agent and a hydroperoxide trapping agent. According to the halogen-free flame-retardant reinforced PBT composition disclosed by the invention, under the combined action of all the components, the effects of improving the flame retardance, the ignition temperature of a glowing filament and the heat-resistant stability can be achieved, and the halogen-free flame-retardant reinforced PBT composition has relatively high mechanical properties. The flame retardant property of the halogen-free flame-retardant reinforced PBT composition reaches V-0 or above, the tensile strength is 95 Mpa or above, the glowing filament ignition temperature is 800 DEG C or above, and the thermal weight loss T1% temperature is 335 DEG C or above.

The invention discloses a production process control system for functional food, and belongs to the technical field of production equipment control systems, and the system specifically comprises a parameter collection module which is used for collecting raw material characteristic parameters of functional food raw materials, and the raw material characteristic parameters comprise rheological characteristic parameters, thermal stability parameters and structural strength parameters; the process adaptation module is used for constructing a dynamic process adaptation model and mapping the raw material characteristic parameters into an equipment control instruction set; dividing energy demand levels according to raw material processing stages, and generating an on-demand energy supply tree structure; the equipment adjusting module is used for monitoring operation state data of the production equipment in real time; triggering a process parameter dynamic compensation instruction based on the equipment operation state data; the equipment feedback module is used for comparing the deviation between the actual product characteristics of the production line and the target characteristics through the closed-loop verification unit, and iteratively optimizing the dynamic process adaptation model; precise production, energy conservation and efficiency improvement of functional food are achieved through the multi-module cooperation technology.

The invention discloses a high-pressure sleeve sheath aging evaluation method and system based on feature unevenness, and belongs to the technical field of high-pressure sleeve operation and maintaining.The method comprises the steps that a to-be-tested high-pressure sleeve sheath is sampled, the interior of a sheath body is selected as a reference area, and meanwhile multiple aging feature areas on the surface of the sheath are selected as aging areas; repairing the sampled insulated damaged area, injecting a nano silicon dioxide modified silicone rubber filler, and performing ultraviolet curing; performing group degradation characteristic test and thermal stability characteristic test on the sampled sample to obtain aging characteristic parameters including characteristic peak absorptivity of each group and thermogravimetric residual rate parameters of different temperature points; taking the aging characteristic parameter of the reference area as a reference value, respectively calculating a single parameter deviation degree of each aging area, and calculating a comprehensive aging non-uniformity value; and according to a comparison result of the comprehensive aging non-uniformity value and a preset grading threshold value, outputting an aging grade of the high-voltage sleeve sheath and a corresponding operation and maintenance strategy.

The invention discloses a heat-dissipation flame-retardant composite material as well as a preparation method and application thereof, and belongs to the field of functional composite materials. The preparation method comprises the following steps: S1, mixing a ceramic filler with a phosphorus-containing modifier, and carrying out inorganic modification to obtain a first modified filler; s2, mixing the first modified filler with an organic modifier to obtain a second modified filler; s3, mixing the second modified filler with the polymer matrix to obtain the heat-dissipation flame-retardant composite material. The organic modifier is at least one of polysilazane, polysilazane and polysiloxane. The phosphorus-containing modifier and the organic modifier are adopted to modify the ceramic filler, so that the flame retardant property, the thermal stability and the high temperature resistance of the composite material are improved, the compatibility between the ceramic filler and the filler and between the filler and a polymer substrate is improved, the dispersity of the ceramic filler in the polymer substrate is improved, and the thermal resistance of the composite material is reduced; and the heat dissipation capability of the composite material is improved.

The invention relates to the technical field of hydrogen storage performance calculation and evaluation, and discloses a method and a system for calculating and evaluating the hydrogen storage performance of a solid hydrogen storage material. Analyzing and designing the mechanical property, electron distribution, heat-conducting property, heat stability and the like of the material; the hydrogen adsorption performance of the newly designed hydrogen storage material is calculated by calculating the adsorption state and adsorption energy of hydrogen molecules on the hydrogen storage material and the hydrogen adsorption capacity of the material under different pressures and temperatures; and drawing a hydrogen adsorption dynamic curve of the solid hydrogen storage material so as to calculate and evaluate the hydrogen storage dynamic performance of the material. The system comprises a performance analysis module, a performance calculation module and a performance evaluation module. The research and development efficiency and hydrogen storage performance of the solid hydrogen storage material can be comprehensively improved in theory and practical application. Each step provides important theoretical support and data basis for solving technical challenges in different aspects.

The invention provides a thermal interface material based on vinyl imidazole ionic liquid as well as a preparation method and application of the thermal interface material. The thermal interface material is prepared from the following raw materials: the vinyl imidazole ionic liquid, a heat-conducting filler subjected to surface treatment by a silane coupling agent, an initiator and a cross-linking agent. The thermal interface material is based on the vinyl imidazole ionic liquid and the heat-conducting filler, the limitation of a traditional thermal interface material base body is broken through, dispensing can be achieved, no solvent is needed in the preparation process, the adverse effect of solvent residues on the performance of a chip when the thermal interface material is applied to the chip subsequently can be avoided, and the thermal interface material has ideal interface bonding strength; the heat conduction effect is remarkable and stable, the heat stability is good, the material can be well attached to an interface, the problems of stress concentration, cracks and the like are not prone to occurring, and the material can be widely applied to the heat conduction and heat dissipation fields of aerospace, advanced energy, electronic information, military industry and the like.

The invention discloses spherical silicon dioxide, a high-frequency high-speed copper-clad plate and a preparation method of the spherical silicon dioxide. The dielectric constant Dk of the spherical silicon dioxide is 3.5 F / m-4. 0F / m, the dielectric loss Df is 0.0001-0.005, the amorphous state proportion is larger than or equal to 99%, the spheroidization rate is larger than or equal to 99%, and the porosity is 0.1%-2%. During preparation, the hydrolysis degree is controlled till partial polycondensation is achieved, then under the oxygen introduction condition, pre-oxidation is conducted at the low temperature to remove alkyl, gradient calcination is conducted at the high temperature, local crystallization influence and defect influence caused by powder spontaneous combustion are prevented, meanwhile, viscous bodies in the microspheres are accurately controlled to flow to fill nanoscale pores, and the particle size is reduced. The spherical silicon dioxide with high purity, high spheroidization rate and low dielectric loss is obtained, the dielectric property of the high-frequency and high-speed copper-clad plate can be met, and the high thermal stability and high reliability of the high-frequency and high-speed copper-clad plate are improved.

The invention relates to the technical field of touch screens, and discloses printing silver paste for a touch screen and a preparation method of the printing silver paste. The prepared silver paste is prepared from silver powder, conductive filler, modified polyurethane resin and an organic solvent as raw materials. Wherein the silver powder and the conductive filler serve as conductive phases, so that the substrate has excellent conductive performance, the hardness, the adhesive force and the thermal stability of the cured silver paste are improved, the use amount of the silver powder is reduced, and the production cost is reduced; and organic silicon is introduced into the modified polyurethane resin, so that the viscosity of polyurethane is reduced, the flowability of the silver paste is improved, and the silver paste is easy to manufacture and process.

The invention belongs to the technical field of high-performance cutter coatings, and relates to a cross-scale bionic gradient coating design method based on a multi-principal-element high-entropy system, which comprises the following steps: sequentially forming a high-entropy alloy plastic layer, a high-entropy alloy / high-entropy ceramic tough layer and a nanocrystalline high-entropy ceramic superhard layer on the surface of a cutter matrix, and constructing a gradient transition structure; the method comprises the following steps: matching a high-entropy alloy plastic layer with a tool matrix binding phase, optimizing a high-entropy alloy / high-entropy ceramic tough layer material, improving interface binding force, optimizing gradient transition design by adopting thermal-mechanical coupling calculation, constructing an atomic model, simulating and optimizing a microstructure based on molecular dynamics, and establishing a finite element model to simulate thermal cycle and mechanical load. The interface performance is optimized, a mathematical model is constructed through a BP neural network and a particle swarm optimization algorithm, and gradual transition design of the tool base body and the coating is achieved. The problems that the tool coating interface is high in brittleness, insufficient in adhesiveness, limited in thermal stability and the like are solved, and the bonding performance of the coating interface and the stability and durability of the coated tool are improved.