114 results about "Particle size ratio" patented technology

The invention provides a positive plate and a preparation method thereof, an all-solid-state battery, a battery assembly and electric equipment. The positive plate comprises a positive active material, a first solid electrolyte and a second solid electrolyte, and the particle size ratio of the positive active material to the first solid electrolyte to the second solid electrolyte is (3-8): 1: (0.1-4). The positive plate can improve the cycle performance of the all-solid-state battery.

The invention provides a negative electrode material, a secondary battery and electric equipment. The negative electrode material comprises a carbonaceous material and meets the following relational expression: 0.4 < = DV50 * S / [| P-OI / 4.8 | * 210] < = 1.1; dV50 [mu] m represents the corresponding particle size when the cumulative volume percentage of the negative electrode material reaches 50%; s m < 2 > / g represents the specific surface area of the negative electrode material; p g / cm < 3 > represents the powder compaction density of the negative electrode material under the pressure of 5T; oI represents the graphite orientation degree of the negative electrode material, and is a peak intensity ratio of a (004) diffraction peak to a (110) diffraction peak in an XRD pattern. By controlling the particle size, the specific surface area, the powder compaction density and the OI value of the carbon negative electrode material to meet a certain relationship, the battery can be endowed with excellent fast charging performance and cycling stability.

A glass powder surface gradient activation-asphalt interface bonding enhancement technology is created for the first time, and the industry bottleneck that the compatibility of waste glass and asphalt is poor is broken through. The core of the method comprises the following steps: 1, an original pretreatment process: carrying out three-stage crushing, wet magnetic separation (the magnetic field intensity is 1.2 T), plasma etching (the ratio of Ar to O2 is 4: 1, and the power is 800W) and controllable ball milling (zirconium oxide balls are used for ball milling) on waste glass; according to interface molecular engineering, a bifunctional silane coupling agent (KH-792: gamma-aminoethyl aminopropyl trimethoxy silane) and titanate (NDZ-201) are compounded with a modifying agent (the mass ratio is 3: 1), and a-Si-O-Ti-cross-linked network 3 is constructed on the surface of the glass powder through in-situ hydrolytic condensation. According to mixture collaborative design, mineral powder is replaced by 35-55% of activated glass powder, and the particle size ratio of the activated glass powder to the mineral powder is 1: 2, D90 is smaller than or equal to 20 [mu] m < 2 >, D90 is smaller than or equal to 20 [mu] m < 2 >, and D90 is smaller than or equal to 20 [mu] m < 2 >. The technical effect of forming a core-shell structure reinforced phase in the SBS modified asphalt is as follows: the dynamic stability reaches 5032 + / -210 times / mm (JTGE20-2011T0719), and compared with the traditional mixture, the water sensitivity (TSR) is improved by 79.7% from 81.3% to 96.5%.

The invention discloses a deep coal seam and geothermal resource combined mining method which comprises the following steps: S1, sample preparation: mixing different rock powders according to a particle size ratio, and pressing into a rock test piece; s2, preparing the device; loading the processed rock test piece into a supporting sleeve, then loading the supporting sleeve into a clamping structure, sealing through a sealing structure, then connecting an injection system and a temperature monitoring system with the clamping structure, and setting test conditions; s3, starting a test, injecting a fluid into the sample through an injection system to complete the test, and recording the temperature change condition of the test piece in the whole test process and the temperature change condition of the fluid flowing through the test piece at the same time; s4, repeating the test, respectively changing the proportion of the rock test piece, the heating temperature of the test piece, the injection pressure and the water injection rate, repeating the test, obtaining a heat exchange change rule in the hot dry rock mining process through comparison, simulating the coal seam water injection process through an indoor test, and analyzing the prevention and control effect of coal seam water injection by changing the water injection condition. And a basis is provided for improving the heat exchange efficiency.

The invention discloses a high-specific-gravity and high-toughness tungsten-nickel-copper material and a preparation method thereof, and belongs to the technical field of non-ferrous metal materials. The material comprises the following components in percentage by mass: 6-15% of nickel; 2-5% of copper; 2-5% of manganese, and the balance tungsten and inevitable impurities. The preparation method of the material comprises the following steps: preparing materials (pure tungsten powder, pure nickel powder, pure copper powder and pure manganese powder), mixing the powder, pressing, sintering, and carrying out recrystallization annealing heat treatment. In the burdening step, two kinds of tungsten powder with different particle size grades are selected and added, and the gradient particle size ratio is adjusted. By adding the strengthening element manganese, combining the gradient particle size ratio and enhancing interface bonding, the high specific gravity and high strength of the material are kept, meanwhile, excellent toughness can be kept, and the material is suitable for aerospace gyroscope rotors and balance weight parts, electronic industry precise instrument parts, medical instrument ray shielding materials and national defense military industry kinetic energy armor-piercing weapon parts.

The embodiment of the invention provides aluminum-based silicon carbide, a preparation method of the aluminum-based silicon carbide, a heat dissipation piece and equipment. The aluminum-based silicon carbide comprises mixed aluminum alloy particles and beta-silicon carbide particles. The beta-silicon carbide particles comprise first beta-silicon carbide particles of which the D50 is 2-4 microns and second beta-silicon carbide particles of which the D50 is 6-12 microns; the first beta-silicon carbide particles account for 20%-45% of the volume fraction of the beta-silicon carbide, and the second beta-silicon carbide accounts for 55%-80% of the volume fraction of the beta-silicon carbide; the beta-silicon carbide particles are spherical particles, and the sphericity of the spherical particles is greater than or equal to 0.80. The spherical beta-silicon carbide particles with different D50 particle size ratios are added into the aluminum alloy, so that the plasticity of the obtained aluminum-based silicon carbide is improved.

The invention provides a single-layer core-shell structure polishing abrasive for silicon carbide wafer polishing, a polishing solution, a preparation method and a polishing method, and relates to the technical field of chemical mechanical polishing, the single-layer core-shell structure polishing abrasive takes silicon dioxide with the particle size of 300-800 nm as an inner core and aluminum oxide with the particle size of 10-150 nm as an outer shell, the particle size ratio of the inner core to the outer shell is 2: 1-10: 1, and the polishing solution is prepared from silicon dioxide with the particle size of 300-800 nm and aluminum oxide with the particle size of 10-150 nm. And single-layer coating is realized through cationic polyelectrolyte assisted electrostatic adsorption. The polishing solution comprises the following components in parts by weight: 3-15 parts of a polishing abrasive with a single-layer core-shell structure, 0.2-8 parts of an oxidizing agent, 0.1-8 parts of a dispersing agent and the balance of deionized water, and the pH value is adjusted to 8-11. The hardness of the inner core abrasive material of the prepared polishing abrasive material with the core-shell structure is smaller than that of the outer shell abrasive material, the polishing abrasive material with the core-shell structure has high dispersity and low agglomeration rate, in the final polishing process of SiC wafers, the surface roughness Ra smaller than or equal to 0.15 nm can be obtained, meanwhile, the material removal rate is kept to be larger than or equal to 1500 nm / h, the scratch density is remarkably reduced, and the polishing abrasive material is suitable for batch finish machining of high-end power device substrates.

The invention provides low-temperature base metal conductive paste and a preparation method and application thereof.The low-temperature base metal conductive paste comprises 86 wt%-90 wt% of a conductive phase, 3 wt%-6 wt% of resin, 0.1 wt%-0.5 wt% of a curing agent, 0.1 wt%-1 wt% of a dispersing agent, 0.1 wt%-3 wt% of an antioxidant, 0.8 wt%-1.4 wt% of an anti-settling agent and the balance solvent, the conductive phase comprises 30-60 wt% of first-class tin-coated copper powder, 10-30 wt% of second-class tin-coated copper powder and 30-60 wt% of pure copper powder, the first-class tin-coated copper powder is spheroidic and / or blocky and has an average particle size D1, the second-class tin-coated copper powder is flaky and has an average particle size D2, the pure copper powder has an average particle size D3, and D1 / D2 is larger than or equal to 0.5 and smaller than or equal to 1, and D1 / D3 is larger than or equal to 6 and smaller than or equal to 16.7. The tin-coated copper powder with different morphologies is matched according to a specific mass ratio and a specific particle size ratio and is further compounded with the pure copper powder according to a ratio, so that a conductive phase system with dense powder accumulation is formed, the electrode resistivity is reduced, metal silver does not need to be used, the dependence of conductive paste on a conductive network formed by silver powder is eliminated, and the remarkable cost reduction effect is achieved.

Provided is a thermally conductive material capable of achieving high thermal conductivity. The present invention is a thermally conductive material formed by dispersing, in a matrix containing a resin, a filler containing spherical particles and plate-shaped particles, the spherical particles containing aluminum nitride, and the plate-shaped particles containing boron nitride. The volume ratio of the plate-shaped particles to the spherical particles is, for example, 0.4-1.5. The particle size ratio of the plate-shaped particles to the spherical particles is 0.05-0.5. The volume ratio of the filler to the entire thermally conductive material is, for example, 73-93 vol%. The thermally conductive material satisfying such conditions can achieve significantly high thermal conductivity. The thermally conductive material is obtained by, for example, a preparation step in which spherical particles, plate-shaped particles, and a resin are blended to obtain a mixture, and a molding step in which the mixture is molded into a molded body. The preparation process can be carried out in multiple stages.

This invention provides a brazing filler metal, a brazing filler metal preparation method, and a rectifier brazing method. The brazing filler metal includes a first brazing filler metal and a second brazing filler metal. The brazing filler metal preparation method involves uniformly mixing high-temperature alloy powder and brazing binder at a mass ratio of 2:1 to 3:1 to form the first brazing filler metal; and uniformly mixing BNi2 powder and brazing binder at a mass ratio of 10:1 to 15:1 to form the second brazing filler metal. By specifying brazing filler metals with a specific particle size ratio and applying different types of brazing filler metals in different zones, defects such as incomplete welding and porosity that are difficult to control in large-gap welds during processing and assembly are solved, improving the welding quality of welds with both large and small gaps, thereby increasing the product qualification rate.

The invention relates to the technical field of metal processing, and discloses a simulation method for the grinding surface topography of a mixed-particle-size CBN (Cubic Boron Nitride) grinding wheel. Grinding wheel workpiece motion parameters and abrasive particle geometric parameters are set, a to-be-processed workpiece and a mixed particle size grinding wheel are simulated, and a trajectory equation of a certain abrasive particle under a global coordinate system is determined based on a workpiece surface analysis domain, the grinding wheel workpiece motion parameters and the abrasive particle geometric parameters; according to the trajectory equation, obtaining a trajectory scatter coordinate matrix of the mapping relation between the area where a certain abrasive particle is located and the workpiece surface, and mapping to obtain a minimum coordinate value; the track scatter coordinate matrixes corresponding to all the abrasive particles are mapped repeatedly, and the surface roughness of the workpiece is obtained based on all the coordinate minimum values; and the surface roughness of the workpiece is compared with the preset roughness, the geometrical parameters of the abrasive particles are adjusted based on the comparison result until the obtained surface roughness of the workpiece is smaller than the preset roughness, and the problem that the abrasive particle diameter ratio and the abrasive particle density ratio of an existing mixed particle size grinding wheel are unreasonable in design is solved.

The application discloses high-efficiency aerobic granular sludge and a preparation method and application thereof, and belongs to the technical field of biological wastewater treatment. The application provides high-efficiency aerobic granular sludge and a preparation method thereof. The granular sludge is prepared by taking dewatered sludge with a water content of 60-75% in a wastewater plant as a raw material, and through steps of mud cake crushing, particle size screening, specific gravity air selection and elutriation activation, and has different particle sizes, a specific gravity of 1.04-1.10, a sphericity coefficient of 0.75-0.95, a consistency of 0.50-0.65 and a diameter distance of 1.05-1.50, so that the AGS system can be rapidly started. The high-performance granular sludge can be prepared only by simple processing operation. It has been verified that the granular sludge prepared by the application is added to an aerobic reactor, which helps to achieve the target requirements of rapid starting and stable operation of the AGS system.

This invention provides a low-cost, bimodal particle size distribution titanium-based powder for additive manufacturing, titanium-based parts, and a method for preparing the same. The method utilizes two different medium particle sizes D... 50 Using near-spherical titanium-based powder as raw material, a near-spherical bimodal particle size distribution titanium-based powder with good uniformity is obtained by wet mixing of suspension and rotary degreasing in a furnace. Various near-spherical bimodal particle size distribution titanium-based powders can also be prepared. The difference between these powders lies in the different particle size ratios and mass ratios of the two raw material powders used. The bulk density and flowability of each bimodal powder are tested to determine the range of particle size ratios and mass ratios of the two powders in near-spherical bimodal particle size distribution powders with high bulk density and flowability. This guides the preparation of high-quality near-spherical bimodal particle size distribution titanium-based powders for additive manufacturing. Ultimately, additive manufacturing technology is used to prepare high-performance, low-cost titanium-based parts to meet the stringent performance requirements of titanium components in high-end fields such as aerospace.

The invention discloses an injection molding composition gradient tungsten-copper alloy which is composed of 50-90 wt% of tungsten, 5-45 wt% of copper and 3-7 wt% of modified tin antimony oxide, the injection molding composition gradient tungsten-copper alloy has a C1-C4 four-layer composition gradient, the tungsten content is 80-90 wt%, 70-80 wt%, 60-70 wt% and 50-60 wt%, the mass ratio of C1 to C2 to C3 to C4 is 1: (0.8-1.2): (0.8-1.2): (1-1.4), the modified tin antimony oxide is doped with 0.2-0.6 mol% of La and 0.3-0.9 mol% of Y, and the conductivity of the alloy is improved. The particle size ranges of the tungsten powder, the copper powder and the modified tin antimony oxide which serve as raw materials are 200-300 nm, 50-150 nm and 10-30 nm respectively, and the compactness and uniformity of the alloy are improved through different particle size ratios. According to the preparation method of the alloy, injection molding and plasma discharge sintering are combined, the process is simple, consumed time is short, and the product is high in sintering strength and excellent in mechanical property and has good application prospects.

The present application provides a kind of polyurethane foam of wide frequency range sound absorption.The polyurethane foam of wide frequency range sound absorption includes polyurethane matrix and the porous polyurethane microsphere of bimodal distribution of particle size dispersed therein, the porous polyurethane microsphere is prepared by incomplete reverse emulsification method, its particle size presents bimodal distribution, the particle size ratio of large particle size porous microsphere and small particle size porous microsphere is 2:1~10:1, and the total mass ratio of large particle size porous microsphere and small particle size porous microsphere is 0.5:1~4:1.The present application is dispersed by bimodal distribution of porous polyurethane microsphere in polyurethane foam material, so as to obtain the polyurethane foam sound absorption material of wide frequency range, and the method process is simple.

The invention discloses an armored sand-ceramsite bimodal proppant based on performance matching as well as a preparation method and application thereof, and relates to the technical field of oil and gas exploitation. The proppant comprises ceramsite and armored sand which are compounded according to the mass ratio of (20: 80)-(60: 40), the volume density ratio of the ceramsite to the armored sand is 0.9-1.1, the median particle size ratio of the ceramsite to the armored sand is 1.5-3.0, it can be ensured that the proppant is evenly and stably conveyed to a target crack, the ceramsite forms a bearing framework, gaps are filled with the armored sand, and a synergistic and stable composite supporting structure is constructed. According to the proppant, the four-in-one performance matching design of volume density, breakage rate, acid solubility and particle size is adopted, the obtained proppant is superior to a conventional proppant in breakage resistance, acid corrosion resistance and long-term flow guide performance, the preparation cost is low, the defects of performance mismatch, system failure and the like of the conventional proppant can be overcome, and the proppant has wide application prospects in hydraulic fracturing construction of oil and gas fields.

To enable stable and inexpensive provision of highly dense, highly heterogeneous sintered particles for radiation shielding materials.SOLUTION: Sintered particles for radiation shielding material are provided for radiation shielding tools, the sintered particles being produced by using LiF, or LiF mixed with one or more fluorides selected from MgF2, CaF2, NaF, AlF3, and / or BaF2, to form spheres with a particle size ratio of 1.2 or less and sintering the spheres.SELECTED DRAWING: Figure 2

The invention discloses a formula design and a preparation method of high-permeability soft magnetic composite powder, and the high-permeability soft magnetic composite powder comprises the following components in parts by weight: 20-30 parts of amorphous magnetic powder with D50 distribution of 25 [mu] m; 70-80 parts of carbonyl iron powder, wherein D50 distribution is 9 [mu] m; the adhesive is composed of epoxy resin, an anhydride curing agent and gamma-aminopropyltriethoxysilane, the anhydride curing agent accounts for 20% of the weight of the adhesive, the gamma-aminopropyltriethoxysilane accounts for 6.7% of the weight of the adhesive, and two molecular ends of the gamma-aminopropyltriethoxysilane are chemically bonded with hydroxyl on the surface of the magnetic powder and the epoxy resin respectively; the particle size ratio of the amorphous magnetic powder to the carbonyl iron powder is controlled to be (2.5-3): 1. According to the formula design, the magnetic powder with a specific proportion and a specific particle size ratio is mixed, and a special adhesive is matched to enhance the interface bonding force, so that the defect of single magnetic powder is overcome.

The present invention discloses a high-strength diamond-boron carbide composite ceramic material and a preparation method thereof. The preparation method comprises the following steps: preparing a powder raw material, molding, degreasing, and siliconizing and sintering. The powder raw material preparation comprises: using diamond powder and B4C powder as raw materials, adding a binder, mixing the raw materials, and drying to obtain a mixed material. The diamond powder comprises diamond micropowder and diamond nanopowder. The particle size of the diamond micropowder is 5 to 100 μm, the particle size of the diamond nanopowder is 5 to 500 nm, and the particle size of the B4C powder is 50 to 300 μm. The particle size ratio of the diamond micropowder, diamond nanopowder, and B4C powder is 1:(0.001 to 0.02):(3 to 10). By controlling the particle size range and particle size ratio of the diamond powder and the boron carbide powder and adopting a specific method for preparing the powder raw material, the present invention can effectively improve the powder fluidity and reduce friction, and also reduce the impact of the siliconizing reaction on the performance of the ceramic material.

The invention belongs to the technical field of water purification filtering materials, and particularly relates to a degerming carbon rod as well as a preparation method and application thereof. The degerming carbon rod comprises first active carbon particles, second active carbon particles, a metal oxide, a polyethylene binder and a bacteriostatic agent. The ratio of the D50 particle size of the first activated carbon particles to the D50 particle size of the second activated carbon particles is (1.2-3.0): 1; the ratio of the D50 particle size of the second active carbon particles to the D50 particle size of the metal oxide is (1.2-5.0): 1; the D50 particle size of the metal oxide is 20-50 [mu] m; and the content of the metal oxide in the degerming carbon rod is 4-8wt%. The key point of the invention is to regulate and control the D50 particle size proportion and mass ratio of the first activated carbon particles, the second activated carbon particles and the metal oxide, so that the obtained carbon rod not only has low pressure drop and high flow rate, but also has high filtration precision, high sterilization rate and high disinfection byproduct removal rate.

Embodiments of the present application provide an aluminum-based silicon carbide, a preparation method thereof, a heat dissipation member and equipment. The aluminum-based silicon carbide comprises mixed aluminum alloy particles and beta-silicon carbide particles. The beta-silicon carbide particles comprise first beta-silicon carbide particles with a D50 of 2-4 mu m and second beta-silicon carbide particles with a D50 of 6-12 mu m. The volume fraction of the first beta-silicon carbide particles in the beta-silicon carbide is 20-45%, and the volume fraction of the second beta-silicon carbide in the beta-silicon carbide is 55-80%. The beta-silicon carbide particles are spherical particles, and the sphericity of the spherical particles is greater than or equal to 0.80. The present application improves the plasticity of the obtained aluminum-based silicon carbide by adding spherical beta-silicon carbide particles with different D50 particle size ratios in the aluminum alloy.

The invention discloses a high-strength diamond and boron carbide composite ceramic material and a preparation method thereof. The preparation method of the ceramic material comprises the following steps: preparing a powder raw material, molding, degreasing and siliconizing and sintering, the powder raw material preparation comprises the steps that diamond powder and B4C powder serve as raw materials, a binder is added for raw material mixing and drying, and a mixed material is obtained; the diamond powder comprises diamond micro-powder and diamond nano-powder, the particle size of the diamond micro-powder is 5-100 [mu] m, the particle size of the diamond nano-powder is 5-500 nm, the particle size of the B4C powder is 50-300 [mu] m, and the particle size ratio of the diamond micro-powder to the diamond nano-powder to the B4C powder is 1: (0.001-0.02): (3-10). The particle size range and the particle size ratio of the diamond powder and the boron carbide powder are controlled, and the powder raw material is prepared in a specific mode, so that the powder fluidity can be effectively improved, the friction force can be reduced, and the influence of siliconizing reaction on the performance of the ceramic material can be reduced.

A thermally conductive material obtained by dispersing a filler in a matrix composed of a resin. The filler includes spherical particles composed of aluminum nitride and plate-like particles composed of boron nitride. The volume ratio of plate-like to spherical particles is, for example, 0.4 to 1.5. The particle diameter ratio of the plate-like to the spherical particles is, for example, 0.05 to 0.5. The volume percent of the filler to the thermally conductive material as a whole is, for example, 73 to 93 vol %. The thermally conductive material that satisfies such conditions can develop remarkably high thermal conductivity. The thermally conductive material can be produced through a preparation step of obtaining a mixture in which spherical particles, plate-like particles, and a resin are present in a mixed manner, and a molding step of forming the mixture into a molded body. The preparation step may be performed in multiple stages.

The invention relates to the technical field of sliding bearings, in particular to a self-lubricating bearing and a preparation method and application thereof. According to the preparation method of the self-lubricating bearing, a compact copper powder transition layer and a porous copper powder buffer layer are formed by laying and sintering on a substrate supporting layer, a gradient copper powder layer with the median particle size ratio larger than or equal to 7.5: 1 and the porosity difference larger than or equal to 25% is formed, and the porous copper powder buffer layer forms the communicating aperture of 200-500 microns; carrying out thermoplastic film forming on a mixed material containing PEEK resin, whiskers, a solid lubricant and a flow modifier, and controlling the cooling speed to be 20-80 DEG C / s; and after the obtained toughened PEEK film and a gradient copper powder layer are subjected to hot-pressing compounding, 0.5-2 MPa back pressure is applied at the temperature of 150-170 DEG C, and reverse rolling welding forming is carried out. Through gradient pore structure design and molding process innovation, the problems that an existing injection molding PEEK bearing is insufficient in ductility, low in interface bonding strength and prone to cracking after being rolled back are solved.

This invention discloses a method for preparing high-entropy zirconate PVD ceramic films. The method involves first spray-granulating five rare earth oxides—nano-Sm₂O₃, nano-Eu₂O₃, nano-Tb₂O₃, nano-Dy₂O₃, nano-Lu₂O₃, and nano-ZrO₂—with zirconium oxide to obtain target raw material powder. After sieving, spherical powders with different particle size ratios are obtained. These powders are then used to fabricate target green bodies using cold isostatic pressing, followed by sintering. Finally, the high-entropy zirconate EB-PVD target is deposited onto a smooth and glossy PVD substrate using PVD technology to form a high-entropy zirconate PVD ceramic film. The high-entropy ceramic film prepared using PVD technology exhibits significantly improved high-temperature stability, capable of withstanding environments exceeding 1500℃, enhanced interfacial adhesion, and adaptability to repeated thermal cycling requirements.

The present invention discloses a full-flotation lithium process method based on lithobite combined with multiple collectors. The present invention provides an application of a reagent composition for flotation of lithobite without desliming, and the full-flotation of lithobite is carried out. The lithobite is coarsely ground by a jaw crusher and finely ground by a roller crusher, thereby ensuring a particle size ratio of 38% to 42% for particles of 40 to 200 mesh and 58% to 62% for particles of -200 mesh. This allows the muddy lithobite and the reagent to fully interact, achieving thorough dispersion of the ore pulp solution and making the surface of the lithobite hydrophobic. A large amount of concentrate is flotated by adding a pH adjuster, an inhibitor, and a first collector in rough selection. A high-grade and high-recovery lithobite concentrate product is obtained by adding a second collector in primary selection and secondary selection. The lithium grade and lithium loss rate in the tailings are reduced by primary and secondary scavenging.

The invention provides a vibrating screen device which comprises a first vibrating area, a second vibrating area, a third vibrating area and a fourth vibrating area which are sequentially connected, the first vibrating area is provided with a plurality of first screen holes, the ratio of the width of the first screen holes to the particle size of target particles is smaller than 1, and the ratio of the length of the first screen holes to the particle size of the target particles is smaller than 1; the second vibration area is provided with a plurality of second sieve pores, and the ratio of the width of the second sieve pores to the particle size of target particles is smaller than 1; the third vibration area is provided with a comb tooth structure, the comb tooth structure comprises a plurality of comb tooth pieces arranged at intervals, and the ratio of the distance between every two adjacent comb tooth pieces to the particle size of the target particles is smaller than 1; the fourth vibration area is provided with a discharging port, the ratio of the width of the discharging port to the particle size of the target particles is larger than 1, and the ratio of the length of the discharging port to the particle size of the target particles is also larger than 1. Through the special screen surface structure design, hairiness is removed for multiple times, and the separation efficiency and the separation effect of target particles and hairiness are improved.

Provided is a silica that exhibits a high matting property when utilized as a matting agent for a paint, and can also suppress the occurrence of cloudiness. The silica has an aggregated structure in which primary particles are aggregated, has a particle diameter ratio R represented by the following equation (1) of from 4.3 to 5.2, has an absorbance of 0.6 or less for light having a wavelength of 700 nm as an aqueous dispersion having a concentration of 1.48 mass %, and has a particle density measured with a He pycnometer of 2.18 g / cm3 or more: Equation (1) R=LD50 / CD50 (in the equation (1), LD50 represents a volume-based 50% cumulative particle diameter (μm) of the silica measured based on a laser diffraction / scattering method, and CD50 represents a volume-based 50% cumulative particle diameter (μm) of the silica measured based on a Coulter counter method).

The invention belongs to the technical field of pouring sealants, and particularly relates to a preparation method of an insulating organic silicon pouring sealant with low dielectric constant and high thermal conductivity, the insulating organic silicon pouring sealant comprises a component A and a component B, the component A comprises the following preparation raw materials in percentage by weight: 10-20% of vinyl silicone oil, 2-3% of hydrogen-containing silicone oil, 0.1-0.5% of a reaction inhibitor, 60-70% of ferrochrome, 8-18% of polyvinyl alcohol and 3-10% of pure water; the component B comprises the following preparation raw materials in percentage by weight: 10-20% of vinyl silicone oil, 0.1-1% of a platinum catalyst, 60-80% of ferrochrome, 9-19% of polyvinyl alcohol, 3-10% of pure water and 0.1-0.5% of color master batch. By adjusting the formula, the low-dielectric-constant ferrochrome is added as an inorganic filler to reduce the dielectric constant of the pouring sealant, the ferrochrome has excellent thermal conductivity and can improve the thermal conductivity of the pouring sealant under different particle size ratios, and the polyvinyl alcohol is added to the formula, so that the insulating capacity of the pouring sealant can be improved, and the pouring sealant is low in viscosity and high in heat conductivity. The potting requirements of electronic product components can be met, the weather resistance and reliability of the electronic components are improved, and the service life is prolonged.

The invention relates to the technical field of binder spray forming manufacturing, and discloses a method for regulating and controlling the surface roughness of a binder spray forming initial blank. The method comprises the following steps: acquiring a particle size reference ratio of raw material powder, preparing an initial blank by adopting a binder spray forming process according to the ratio, measuring the surface roughness of the initial blank to obtain a measured value, and comparing the measured value with a target roughness threshold value. And when the measured value is larger than the target roughness threshold value, the particle size ratio of the raw material powder is adjusted through the calculation model. And repeating the steps of preparing the initial blank, measuring the surface roughness and comparing until the measured value of the surface roughness is less than or equal to the target roughness threshold value. According to the method, accurate regulation and control of the surface roughness of the initial blank are achieved, diversified requirements of different products for the surface quality can be met, meanwhile, the method has the advantages of being efficient, low in cost and the like, and powerful support is provided for wide application of the binder spray forming technology in the manufacturing industry.