6610 results about "Silicon oxide" patented technology

The invention provides an iron tailing-based geopolymer electromagnetic wave attenuation performance optimization control method and system, and relates to the technical field of electromagnetic wave attenuation, and the method comprises the steps: 1, setting a synthesis condition parameter set of an iron tailing-based geopolymer in a simulation environment, comprising virtual matching of raw materials, particle size distribution, concentration gradient of an alkali activator and curing temperature-time coupling parameters, and a forming process is deduced through an amorphous phase topological configuration and a pore network evolution rule of aluminosilicate gel in a geopolymer microstructure; and step 2, constructing an interface reaction kinetics process based on the synthesis condition parameter set, and generating an enhanced interface digital mapping system with periodically arranged aluminum oxide and silicon oxide regular tetrahedrons through virtual iteration of mineral admixture ratio and forming process parameter boundary conditions. According to the method, a strengthened interface is constructed through simulation synthesis, a loss layer database is established, and microstructure regulation and control and multi-band electromagnetic wave efficient attenuation are achieved.

The invention discloses a lithium battery diaphragm coating based on a nano material and application thereof, and relates to the technical field of lithium battery diaphragms. The coating comprises the following raw materials in parts by weight: 15-25 parts of polystyrene maleic anhydride copolymer modified polyvinylidene fluoride, 10-20 parts of polystyrene, 2-4 parts of nano silicon nitride, 3-6 parts of a boehmite / aluminum oxide and silicon dioxide composite material, 1-2 parts of a dispersing agent and 65-90 parts of a solvent, according to the lithium battery diaphragm coating provided by the invention, the wettability and absorptivity of a diaphragm to an electrolyte are remarkably improved, meanwhile, the lithium battery diaphragm coating also has excellent thermal stability, and the diaphragm can be effectively prevented from thermal shrinkage or melting under a high-temperature condition, so that the safety performance of a battery is remarkably enhanced.

The invention relates to an insulating weather-resistant powder coating and a preparation method thereof, and belongs to the technical field of coatings, and the powder coating comprises composite modified resin, a dual curing agent, a functional filler, a polyacrylate leveling agent, fumed silica, a benzotriazole ultraviolet light absorber, polytetrafluoroethylene wax powder and the like. A core-shell structure of the composite modified resin is designed, high insulativity is kept through a silane modified epoxy core layer, a weather-proof barrier is provided through an acrylic acid shell layer, and the phase separation problem is solved through interface chemical bonding; a dual-curing mechanism is designed, and isocyanate and acrylic hydroxyl react to form an interpenetrating network while an epoxy core layer is cured by anhydride; a filler synergistic effect is designed, silane coupling agent modified nano boron nitride forms a three-dimensional heat-conducting insulating network, and rutile type titanium dioxide is coated with silicon dioxide, so that ultraviolet aging is resisted. All the components cooperate with one another, so that the coating has excellent insulativity, weather resistance, adhesiveness and the like at the same time.

The invention provides a doped electrode material based on porous silicon carbon and a preparation method thereof.The preparation method comprises the steps that a resin base material is smashed and then put into a high-temperature furnace to be subjected to a carbonization process, the carbonization temperature ranges from 300 DEG C to 1500 DEG C, an alkaline additive, a phosphorus source material and a nitrogen source material are sequentially added in the temperature interval, and phosphorus-nitrogen co-doped porous carbon is obtained; the preparation method comprises the following steps: mixing a silicon dioxide microsphere template into phosphorus-nitrogen co-doped porous carbon, adding a first coating carbon source to carry out first coating treatment, and etching the silicon dioxide microsphere template by using an etching solution to obtain a prefabricated object with a cavity structure; and putting the prefabricated object with the cavity structure into a fluidized bed reactor, introducing silicon source gas and a surface activation auxiliary agent, carrying out deposition at 400-550 DEG C, and then adding a second coating carbon source to carry out secondary coating treatment, thereby obtaining the doped electrode material based on porous silicon carbon. Therefore, the expansion coefficient of the electrode material is effectively reduced, and the rate capability is improved.

The invention relates to a preparation method of spherical silicon dioxide micropowder with ultralow dielectric loss. The preparation method comprises the following steps: preparing an organic silicon polymer; preparing slurry; performing solid-liquid separation on the synthetic slurry to obtain concentrated slurry, and drying the concentrated slurry to obtain spherical silica powder; carrying out low-temperature heat treatment on the obtained spherical silica powder at 1500-7000 DEG C for h to remove residual organic matters and free water in the powder; then, high-temperature densification is carried out at the temperature of 3000-28000 DEG C for h, and moisture is further removed; adding a modifier into the stirring equipment for surface modification; and after surface modification, drying at 55-300 DEG C for h, and removing modified micromolecular byproducts to obtain the spherical silicon dioxide micro powder with ultralow dielectric loss. The method is simple in production process, short in production period, low in production cost, high in yield and capable of effectively reducing the dielectric loss of the spherical silicon dioxide micro powder.

The invention relates to the field of building materials, and discloses a multifunctional foamed ceramic sound insulation and heat preservation material for buildings. Comprising the following raw materials in parts by weight: 42 to 48 parts of pottery clay tailings, 14 to 16 parts of fly ash, 10.5 to 12 parts of crushed stone materials, 2.8 to 3.2 parts of a silicon carbide foaming agent, 0.7 to 0.8 part of a borax fluxing agent, 7 to 8 parts of paraffin / silicon dioxide phase change microcapsules, 0.5 to 1.0 part of graphene, 2.0 to 2.5 parts of nano iron powder, 0.05 to 0.5 part of nano silver, 1.0 to 1.5 parts of photocatalytic titanium dioxide and 0.3 to 0.4 part of a fluorosilane coupling agent. A stable matrix structure is constructed through the argil tailings, the fly ash and the crushed stone materials, the silicon carbide foaming agent and the borax fluxing agent reduce the heat conductivity coefficient, the sound insulation performance is improved, the material is endowed with the antibacterial ability through nano-silver and photocatalytic titanium dioxide, indoor sanitation is guaranteed, and a super-hydrophobic layer is constructed through the fluorosilane coupling agent.

The invention relates to the technical field of solar cells, and particularly discloses a back contact solar cell and a preparation method thereof, a cell assembly and a photovoltaic system, the back contact solar cell comprises a silicon substrate, the silicon substrate is provided with a first surface, a second surface and a side surface, the first surface and the second surface are oppositely arranged, and the side surface is respectively connected with the first surface and the second surface; the anti-reflection passivation composite layer comprises a first branch part arranged on the first surface and a second branch part extending from the edge of the first branch part to the outside of the side surface; the anti-reflection passivation composite layer comprises an ultrathin silicon oxide layer, an aluminum oxide layer, a silicon nitride layer, a silicon oxynitride layer and a silicon oxide layer which are sequentially arranged in the direction away from the silicon substrate, and the refractive indexes of the silicon nitride layer, the silicon oxynitride layer and the silicon oxide layer are sequentially decreased. Influences brought by defects on the side face of the silicon substrate can be effectively solved, parasitic absorption on the edge of the cell can be reduced, the anti-reflection and passivation effects of the anti-reflection and passivation composite layer can be effectively improved through mutual cooperation of the multiple material layers, the stress problem can be improved, the conversion efficiency of the cell can be integrally and effectively improved, and the service life of the cell can be prolonged. And the long-term reliability of the battery is ensured.

The invention provides a germanium-silicon groove preparation method, which comprises the following steps of: forming a PMOS (P-channel Metal Oxide Semiconductor) gate structure and an NMOS (N-channel Metal Oxide Semiconductor) gate structure on a semiconductor substrate, arranging a first silicon nitride layer, a silicon oxide layer and a second silicon nitride layer in hard mask layers of the PMOS gate structure and the NMOS gate structure, exposing the second silicon nitride layer through a gate side wall, and covering a germanium-silicon mask layer, a patterned photoresist protection NMOS gate structure is formed, the germanium-silicon mask layer exposed in the PMOS region is etched, a groove is formed, and at least part of the second silicon nitride layer is reserved at the top of the PMOS gate to protect the silicon oxide layer; according to the method, the first silicon nitride layer and the germanium-silicon mask layer are etched, germanium-silicon deposition is carried out, and the residual second silicon nitride layer and the germanium-silicon mask layer are removed together through wet etching, so that the height difference of the hard mask layer caused by the conventional process of the PMOS gate and the NMOS gate is eliminated, the process load is avoided, the process steps are simplified, and the process cost is reduced.

The invention provides a SiO2 / TiO2 / PMMA radiation refrigeration film and a preparation method thereof, and relates to the technical field of passive daytime radiation refrigeration films. The radiation refrigeration film is prepared from the following raw materials: N, N-dimethylformamide, polymethyl methacrylate, silicon dioxide and titanium dioxide. The invention relates to a preparation method of a SiO2 / TiO2 / PMMA radiation refrigeration film. The preparation method comprises the steps of preparing silicon dioxide, preparing titanium dioxide, synthesizing composite sol and preparing the SiO2 / TiO2 / PMMA radiation refrigeration film. The SiO2 / TiO2 / PMMA radiation refrigeration film prepared by the invention has high reflectivity in the ultraviolet-visible-near infrared band and high emissivity in the infrared band, can realize 8.4 DEG C sub-environment refrigeration, and is low in cost and simple in process flow.

The invention provides a negative plate and a battery. The negative plate comprises a negative current collector and a coating, and the coating is divided into an inner layer and an outer layer; the inner layer is close to the surface of the negative current collector and the outer layer is away from the surface of the negative current collector; the first negative electrode active substance of the inner layer comprises a silicon-based negative electrode material, and the silicon-based negative electrode material comprises at least one of silicon oxide, silicon carbide, nano silicon and silicon alloy. The second negative electrode active material of the outer layer comprises a carbon negative electrode material, and the carbon negative electrode material comprises at least one of natural graphite, artificial graphite, hard carbon, soft carbon, mesocarbon microbeads and graphene. By adopting the specific double-layer active material layer structure, the performance of the negative electrode is effectively improved, and the energy density and the fast charging performance of the battery are improved. Meanwhile, due to the special multi-layer structural design, the volume expansion effect of the silicon-based negative electrode material can be effectively relieved, the structural stability of the negative electrode is optimized, the structural stability of the negative electrode can be kept for a long time in the charge-discharge cycle, and then the battery performance is optimized.

The invention discloses a self-cleaning waterproof coating and a preparation method thereof, and relates to the technical field of waterproof coatings. Wherein the waterproof coating is prepared from organic silicon modified acrylic resin emulsion, a photocatalyst nano composite material, hydrophobic modified silicon dioxide aerogel powder, a nanofiber reinforced material, a dispersing agent, a coalescing agent, a thickening agent, a defoaming agent and deionized water; through the compatibility design of the core-shell structure photocatalyst and the super-hydrophobic silicon dioxide aerogel, multiple self-cleaning of adsorption, degradation and scouring is achieved, the durability and reliability of self-cleaning are remarkably improved, surface modified nanofibers are adopted as a reinforcing material, a three-dimensional network structure is formed in a coating film, and the self-cleaning performance is improved. And the flexibility of the organic silicon modified acrylic resin is synergistically complemented, so that the tensile strength and the deformation resistance of the coating are improved, the brittleness problem of rigid particles is avoided, and the durability of the coating is remarkably improved.

The present invention is a negative electrode active material comprising negative electrode active material particles. The negative electrode active material is characterized in that: the negative electrode active material particles include porous carbon structures; silicon and a silicon oxide are dispersed in the interiors of the porous carbon structures; a low-valent nanosilicon oxide in an amorphous state is dispersed in at least surface-layer portions of the interiors of the porous carbon structures; the low-valent nanosilicon oxide is SiOx, where x is less than 1.0; and nanosilicon with a crystalline structure is dispersed at least in deep layer portions of the interiors of the porous carbon structures, such portions being deeper than where the low-valent nanosilicon oxide is dispersed. Due to this configuration, it is possible to provide a negative electrode active material that can increase capacity while maintaining battery characteristics.

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 transparent radiation refrigeration film and radiation refrigeration ceramic for building heat management and a preparation method of the transparent radiation refrigeration film and the radiation refrigeration ceramic. According to the film and the ceramic, SiO2 nano-particles are selected as base materials for achieving radiation refrigeration, dendritic silicon oxide nano-particles are adopted as inorganic particle emission materials of the film, PDMS is adopted as a polymer matrix, ITO coating PET is adopted as a flexible substrate, DMSNs are dispersed in PDMS, and the film is formed on the ITO-PET substrate through a blade coating technology. The white or colored ceramic takes spherical SiO2 nano-particles as a radiation refrigeration material and is sintered into white SiO2 porous ceramic, namely white radiation refrigeration ceramic, through phase inversion, and then the white radiation refrigeration ceramic is colored through chemical dye to form the colored ceramic. The radiation refrigeration film is good in transparency and bright in ceramic color, both the radiation refrigeration film and the ceramic have excellent radiation refrigeration performance, the transparent film can achieve the indoor cooling effect of about 12 DEG C on sunny days, and the colored ceramic can achieve the cooling effect of about 5 DEG C on sunny days.

The invention discloses a high-weather-resistance bismuth vanadate coating and a preparation method thereof, and belongs to the technical field of inorganic pigment modification. The high-weather-resistance bismuth vanadate coating comprises bismuth vanadate matrix particles, and the surfaces of the bismuth vanadate matrix particles are sequentially coated with an amorphous aluminum oxide layer, a cerium oxide layer and a fluorinated silicon oxide layer. The amorphous aluminum oxide layer is formed in an atomic layer deposition mode; the cerium oxide layer is formed by hydrothermal treatment of a cerium source. The preparation technology has accurate and controllable technological parameters, is suitable for industrial production, can replace the traditional toxic pigment containing lead and cadmium, and meets the requirements of environmental regulations. The bismuth vanadate coating has excellent weather resistance and chemical stability, the service life of a product can be prolonged, the maintenance cost is reduced, and a reliable solution is provided for development of high-performance environment-friendly pigments.

The invention provides base metal conductive paste for a photovoltaic cell and a preparation method, a use method and application thereof, and the conductive paste comprises the following components in percentage by mass: 5-60wt% of oxide coated base metal powder, 27-77wt% of silver powder, 2-5wt% of glass powder, 0.1-3wt% of an antioxidant aid and the balance of an organic carrier; wherein the base metal powder comprises one or more of copper, tungsten, tin, nickel, aluminum and alloy powder of the copper, the tungsten, the tin, the nickel, the aluminum and the alloy powder of the aluminum, and the oxide comprises one or more of silicon oxide, aluminum oxide, titanium oxide and boric oxide. The base metal powder coated with a specific type and a proper amount of oxide is selected and matched with the oxide and the glass powder which are good in compatibility, the manufacturing cost of the conductive paste and the battery can be effectively reduced, meanwhile, the conductive paste is applied to TOPCon and BC batteries, and the battery conversion efficiency can be kept equivalent to or even superior to that of traditional pure silver conductive paste.

The invention belongs to the technical field of heat-conducting materials, and provides liquid metal-based composite heat-conducting silicone grease as well as a preparation method and application thereof. The modified silicone oil, the liquid metal, the heat-conducting auxiliary filler and the hydrophobic fumed silica in a specific ratio are used as main components of the liquid metal-based composite heat-conducting silicone grease, and the liquid metal-based composite heat-conducting silicone grease prepared by the invention has high heat conductivity coefficient (up to 6.05-10.0 W / mk) and low heat resistance (as low as 0.01-0.03 DEG C * cm < 2 > / W), can maintain a good appearance in double-85, high temperature 125 DEG C and temperature cycle aging tests, and has a wide application prospect. Therefore, the structure is suitable for an assembly interface of a power module and a radiator with high-power heat dissipation requirements, and the heat dissipation efficiency is improved.

The invention discloses an MXene-based coating with a near-infrared light induction interaction effect and a preparation method of the MXene-based coating, and relates to the technical field of coatings. The preparation method comprises the following steps: a nano microcapsule and MXene powder are subjected to in-situ growth to form a composite dispersion liquid, the nano microcapsule is of a core-shell structure, a shell layer material is selected from at least one of polyaniline, polyurea, polyurethane, polyacrylate and silicon dioxide, a core contains a functional substance, and the surface of the core contains a porous material. The functional substances are selected from at least two of a corrosion inhibitor, a fluorescent indicator and a lubricant; adding a thermal reversible coating containing dynamic covalent bonds and a curing agent into the composite dispersion liquid, and uniformly mixing to form a homogeneous coating; and spraying the homogeneous coating on the surface of a base material, and curing to obtain the coating. The coating is high in mechanical strength, has a near-infrared light triggered self-repairing function, is high in self-repairing rate, and can realize multiple functions such as fluorescence labeling, corrosion early warning and lubrication coordinated regulation and control.

The invention relates to a back contact photovoltaic cell piece, a back contact photovoltaic cell assembly and a preparation method, and relates to the technical field of photovoltaic cell pieces. According to the preparation method, at least part of the structure of the surface of the silicon substrate is subjected to at least two times of texturing treatment to form a textured surface, in the two adjacent times of texturing treatment, the concentration of a texturing solution used in the later texturing treatment is smaller than that of a texturing solution used in the previous texturing treatment, the substrate is dried by ozone, and the textured surface is formed. And at least forming a silicon oxide passivation layer on the textured surface. Through at least two times of texturing treatment, the average size of the pyramid structure of the formed textured surface is relatively small, the density of the pyramid structure of the textured surface is relatively large, and the distribution uniformity degree of the pyramid structure of the textured surface is relatively large. The back contact photovoltaic cell prepared according to the preparation method has the advantages of relatively low light reflectivity and relatively low recombination rate, so that the prepared back contact photovoltaic cell can have relatively high photoelectric conversion efficiency.

The invention relates to the field of materials, in particular to a silicon dioxide aerogel composite thermal insulation material and a preparation method thereof. The silicon dioxide aerogel composite thermal insulation material is prepared by taking silicon dioxide aerogel, phenolic resin, a nano zirconium oxide graft and a locust bean gum graft as main raw materials and taking n-pentane, UV-327, hexamethylenetetramine and an antioxidant 1010 as auxiliary materials. The nano zirconium oxide graft and the locust bean gum graft are added into the silicon dioxide aerogel material, so that the prepared silicon dioxide aerogel composite material has excellent heat-insulating property, flame-retardant property and toughening effect, and the comprehensive requirements of the use scene of the silicon dioxide aerogel composite material on toughness and flame retardance are met; and the application market is expanded.

The invention discloses a method for synthesizing tetrahydrofuran from furfural in one step and a preparation method of a catalyst for the tetrahydrofuran. The catalyst is a bimetallic catalyst, bimetallic is M1 and M2, M1 is Pd, and M2 is selected from one of Pt, Rh, Ru, Ni, Cu, Co, Mn and Ce; the catalyst comprises an active component and a carrier, the bimetallic is the active component, and the carrier is selected from at least one of activated carbon, silicon dioxide, aluminum oxide, magnesium oxide, an S-1 molecular sieve, a ZSM-5 molecular sieve, a Beta molecular sieve, an MOR molecular sieve and a Y molecular sieve; based on the total weight of the catalyst, the loading capacity of M1 is 0.5-3.5%, and the loading capacity of M2 is 0.5-3.5%. The catalyst provided by the invention can be used in a reaction for preparing tetrahydrofuran through furfural hydrogenation, and can improve the conversion rate of furfural and the selectivity of tetrahydrofuran.

The embodiment of the invention relates to the photovoltaic field, and provides a back contact cell and a preparation method thereof, and the preparation method of the back contact cell comprises the steps: providing a substrate; forming a tunneling oxide layer and an intrinsic crystalline silicon layer; forming a first silicon oxide layer on the surface of the intrinsic crystalline silicon layer on the second region and the spacer region; carrying out first doping treatment on the intrinsic crystalline silicon layer on the first region, so that the intrinsic crystalline silicon layer on the first region is converted into a first doped conductive layer containing a first doping element; removing the first silicon oxide layer; forming a second silicon dioxide layer on the first doped conductive layer and the surface of the intrinsic crystalline silicon layer on the spacer region; performing second doping treatment on the intrinsic crystalline silicon layer on the second region, so that the intrinsic crystalline silicon layer on the second region is converted into a second doped conductive layer containing a second doping element; and removing the second silicon dioxide layer. According to the embodiment of the invention, the performance and preparation efficiency of the back contact battery can be improved at least, and the problem of high preparation process difficulty caused by laser treatment is avoided.

The invention relates to the technical field of titanium dioxide, and discloses a preparation process of oil paint core-coated titanium dioxide, which comprises the following steps: a core layer is rutile type titanium dioxide particles with the particle size range of 0.1-0.5 mu m and the specific surface area of 8-15m < 2 > / g, an inorganic coating layer is composed of silicon dioxide and aluminum oxide according to the mass ratio of 1: (0.2-1.5), the coating thickness is 5-15% of the diameter of the core layer, and the inorganic coating layer is composed of silicon dioxide and aluminum oxide according to the mass ratio of 1: (0.2-1.5). Wherein the silicon dioxide is coated by a hydrolytic deposition method, the aluminum oxide is coated by a sol-gel method, the organic coating layer comprises a copolymer containing a silane coupling agent and organic silicon resin, the organic silicon resin is methyl phenyl silicon resin, the organic coating layer accounts for 1-8% of the total mass of the titanium dioxide, and the surface contact angle of the organic coating layer is greater than or equal to 110 degrees. According to the preparation process of the oil paint core-coated titanium dioxide, an inorganic-organic gradient coating system is constructed, so that the core-coated titanium dioxide has a gloss retention rate of more than 95% (ASTM D523) and a delta E color difference of less than 1.5 (ISO 7724) after 1000 hours in a QUV accelerated aging test, and the weather resistance of the core-coated titanium dioxide is improved by more than 3 times compared with that of the traditional titanium dioxide.

The invention belongs to the technical field of chips, and discloses a vehicle gauge-level SMD chip crystal and a processing method thereof, and the method comprises the steps: forming a gradient doped region on the surface layer of a quartz wafer through an ion implantation technology, and carrying out the recognition of the surface defects of the wafer and the etching of an anchor point groove based on a visual detection system; the etched doped quartz wafer is subjected to micro-electro-mechanical processing, a double-cantilever supporting structure is formed, a three-dimensional electromagnetic shielding layer is constructed on the surface of the wafer subjected to cantilever processing, a ceramic substrate and a metal conducting layer are alternately deposited through an additive manufacturing process, a polyimide-silicon dioxide colloid material is provided, and the three-dimensional electromagnetic shielding layer is formed; gradient distribution of an adhesive layer is realized through a micro-droplet jetting technology, a polyimide-silicon dioxide composite stress buffer layer is coated on a ceramic substrate, alignment and patch packaging are carried out on a processed crystal and a substrate, and through material modification and process collaborative optimization, the method is suitable for application in a high-temperature environment; the reliability problem in the extreme environment of the vehicle gauge is solved, and meanwhile the yield is improved.

The invention discloses a preparation method of a passivation contact cell with double tunneling polycrystalline silicon layers. A first tunneling oxide layer, a first intrinsic amorphous silicon layer, a low-doping p-type amorphous silicon layer, a second tunneling oxide layer, a high-doping p-type amorphous silicon layer and a first silicon dioxide mask layer are sequentially deposited in a p region on the back surface of a silicon wafer; sequentially depositing a third tunneling oxide layer, a second intrinsic amorphous silicon layer, a low-doping n-type amorphous silicon layer, a fourth tunneling oxide layer, a high-doping n-type amorphous silicon layer and a second silicon dioxide mask layer in an n region on the back surface of the silicon wafer; and the p-type amorphous silicon and the n-type amorphous silicon are simultaneously converted into p-type polycrystalline silicon and n-type polycrystalline silicon through high-temperature annealing crystallization treatment, so that the preparation of the p-region and n-region dual-tunneling passivation contact structure of the TBC battery is realized. The doping level and passivation performance of the p-region p-type polycrystalline silicon and the n-region n-type polycrystalline silicon are improved, the conversion efficiency of the TBC battery is improved, the production steps are reduced, and the preparation cost is reduced.

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 belongs to the technical field of semiconductors, and discloses a method for manufacturing a sigma trench in a semiconductor device, which comprises the following steps of: providing a substrate which comprises a first device region and a second device region; a PMOS (P-channel Metal Oxide Semiconductor) region gate and a PMOS gate mask layer are formed on the first active region of the first device region; exposing the top of the PMOS gate mask layer outside the first device region photoresist layer; depositing a deposition silicon oxide layer on the top of the second device region and the top of the PMOS gate mask layer; removing the photoresist layer in the first device region; etching to remove the natural silicon oxide layer on the surface of the first active region, further etching silicon in the first active region, and forming a U-shaped groove in the semiconductor substrate in the first device region; and carrying out TMAH etching on the U-shaped groove to form a sigma groove. According to the invention, in the process of embedding germanium-silicon into the source and the drain, the height difference between the PMOS and the NMOS is avoided, and the subsequent process is not influenced.

The invention discloses a self-cleaning photovoltaic super-hydrophobic coating based on a nano-porous structure and a preparation method of the self-cleaning photovoltaic super-hydrophobic coating, and belongs to the technical field of photovoltaic panel coatings. The coating comprises the following components in percentage by mass: 15-25% of nano porous silicon dioxide particles, 5-10% of a low surface energy modifier, 3-8% of photocatalytic nano titanium dioxide, 30-40% of organic silicon resin and the balance of deionized water. The coating has super-hydrophobicity, photocatalytic decomposition of organic matters and wear resistance, can solve the problems of photovoltaic panel dust accumulation, bird droppings, organic matter pollution and the like, and improves the power generation efficiency of a photovoltaic system.

The invention discloses a high-density lithium manganese iron phosphate positive electrode material and a preparation method thereof.The preparation method of the high-density lithium manganese iron phosphate positive electrode material comprises the following steps that 1, an iron source, a lithium source, a manganese source, a phosphorus source, an additive, a dispersing agent and a carbon source are added into deionized water, grinding, drying and sintering are conducted, and a primary material is obtained; and 2, coating the primary material with a polydopamine layer, and sintering to obtain the high-density lithium iron manganese phosphate positive electrode material, wherein the dispersing agent is polyethylene glycol tert-octyl phenyl ether; the carbon source is polyvinyl alcohol and at least one of glucose, carbon nanotubes and graphene; the additive is at least one of magnesium oxide and silicon oxide. The high-density lithium manganese iron phosphate positive electrode material disclosed by the invention has relatively good electrical performance and compaction density, and a battery prepared from the high-density lithium manganese iron phosphate positive electrode material has good electrochemical performance.

The invention provides a preparation method of silicon dioxide serving as a flow promoter in a powder coating. The preparation method comprises the following steps: synthesizing silicon dioxide by using a precipitation method; washing and filter-pressing to obtain a precipitate; re-dispersing and pulping the silicon dioxide by using pure water; performing drying; performing high-temperature crushing; the synthesis of silicon dioxide comprises the following steps: adding bottom water, and heating to 40-100 DEG C; adding water glass and acid into the bottom water in a parallel flow manner under the conditions of constant temperature and pH value of 5.0-10.0; adjusting the pH value to 2.0-4.0 by using an acid; the specific surface area of the silicon dioxide is 100-500m < 2 > / g; the bulk ratio of the silicon dioxide is not higher than 0.30 g / cm < 3 >; the particle size of the silicon dioxide is not higher than 5.0 microns; the methanol value of the silicon dioxide is higher than 30%; the drying weight loss of the silicon dioxide is not higher than 3.0%. The preparation method of the silicon dioxide serving as the flow promoter in the powder coating is simple in process and low in cost.