1542 results about "Nano carbon" patented technology

The invention discloses a microencapsulation repairing agent and an intelligent self-repairing ultrahigh-strength ultrahigh-toughness cement-based structural material, the microencapsulation repairing agent is mainly composed of a humidity-responsive outer layer, a pH-responsive middle layer and a temperature-responsive inner layer, and the outer layer is modified with a silane coupling agent. The intelligent self-repairing ultrahigh-strength ultrahigh-toughness cement-based structural material is mainly prepared from the microencapsulated repairing agent, nano carbon black, nano montmorillonite, nano cellulose and other raw materials. According to the invention, by introducing the self-repairing microcapsule with a specific structure and materials such as nano carbon black, nano montmorillonite and nano cellulose, the strength, toughness and durability of the concrete are remarkably improved, and the concrete has an intelligent self-repairing function.

The invention discloses a preparation method of porous carbon, the porous carbon, a negative electrode material and a secondary battery, the preparation method of the porous carbon comprises the following steps: granulation: drying and granulating a phenolic resin microsphere suspension to obtain powder; nano carbon nanotubes are dispersed in the phenolic resin microspheres; and carbonization: sequentially carrying out secondary curing, pre-oxidation and carbonization on the powder to obtain the porous carbon. According to the preparation method, the porous carbon is prepared by adopting the nanoscale carbon nanotubes, firstly, the conductivity of the porous carbon is favorably improved due to the good conductivity of the carbon nanotubes, and meanwhile, the nanoscale carbon nanotubes are utilized, so that the carbon nanotubes can be more sufficiently dispersed, and the effect of improving the conductivity of the porous carbon by the carbon nanotubes is more favorably exerted; secondly, the tin or germanium element doped into the negative electrode material assists lithium ion deintercalation by reducing lithium ion transition energy barriers, so that the first effect is improved.

The invention relates to the technical field of plastic cups, in particular to a transparent polypropylene medical plastic cup and a preparation method thereof. The plastic cup comprises the following components in parts by weight: 60-80 parts of polypropylene, 3-8 parts of polyformaldehyde, 5-15 parts of modified nano calcium carbonate, 3-5 parts of kaolin, 2-4 parts of talcum powder, 0.2-0.4 part of a nucleating agent, 0.5-1.5 parts of a lubricant, 1-3 parts of an antioxidant and 0.5-1.0 part of a stabilizer. The preparation method comprises the following steps: uniformly stirring polypropylene, polyformaldehyde, modified nano calcium carbonate, kaolin, talcum powder, a nucleating agent, a lubricant, an antioxidant and a stabilizer to obtain a mixture; the mixture is subjected to melt extrusion, granulation and injection molding to obtain the plastic cup, and the plastic cup not only has excellent mechanical properties, but also has excellent antibacterial properties, and can effectively prevent growth of bacteria.

The invention discloses a preparation process of an aluminum oxide ceramic material, which comprises the following steps: S1, pretreatment of aluminum oxide powder: taking alpha-Al2O3 powder as a raw material, adding a dispersion medium, carrying out ball milling, transferring into an ultrasonic dispersion machine, dispersing, and further carrying out vacuum drying to obtain pretreated aluminum oxide powder; s2, chemical activation treatment: weighing pretreated aluminum oxide, magnesium oxide, nano silicon dioxide, calcium oxide, zirconium dioxide, titanium dioxide and modified nano silicon carbide in parts by weight, mixing, sequentially adding a dispersing agent absolute ethyl alcohol and a KH550 silane coupling agent, stirring at a high speed, adding a polyvinyl alcohol binder, and continuously stirring to obtain ceramic slurry; s3, sieving the ceramic slurry, filling the ceramic slurry into a mold, and performing isostatic pressing to obtain a ceramic green body; and S4, putting the ceramic green body into a box-type sintering furnace, sintering step by step, and cooling to room temperature along with the furnace to obtain the aluminum oxide ceramic material. The prepared aluminum oxide ceramic material has high compactness, excellent dielectric strength and mechanical property, low energy consumption and great application potential.

The invention discloses a low-cost, large-quantity and efficient carbon dioxide curing method for a tailing filling body, which adopts a two-step carbon sequestration method and comprises the following steps of: firstly, grinding and screening a tailing raw material, and chemically exciting and activating; secondly, the activated tailings are subjected to first-step carbon sequestration through cooperation of a wet method and ultrasonic, and carbon sequestration tailings are prepared; then preparing a mine filling body by using the carbon sequestration tailings and cementing materials such as cement; and finally, through second-step carbon sequestration maintenance, the carbon sequestration filling body with the high carbon sequestration amount is obtained. The carbon sequestration in the first step can stimulate the carbonization and gelation activity of the tailings and increase the carbon sequestration amount on one hand, and nano calcium carbonate and silica gel formed in the prepared carbon sequestration tailings optimize the structural compactness of the filling body and improve various properties on the other hand. According to the carbon sequestration filling body prepared through the second step of carbon sequestration, the compressive strength of 3 days can reach 3 MPa or above, the compressive strength of 28 days can reach 5 MPa or above, the carbon sequestration amount can reach 13 wt.% or above, and the carbon sequestration filling body has the advantages of being simple in process, good in performance and low in cost.

The invention discloses a waterproof heat-resistant adhesive and a preparation method thereof, and relates to the technical field of adhesives. Tetramethyltri-3-trifluoropropyl cyclotetrasiloxane is used as a raw material to prepare hydroxyl-terminated organic fluorosilicone oil and modified epoxy resin, fluorine atoms are closely arranged around a main chain of the hydroxyl-terminated organic fluorosilicone oil and modified epoxy resin in an umbrella shape, and the hydroxyl-terminated organic fluorosilicone oil and modified epoxy resin cooperate with organic silicon to improve the waterproof and heat-resistant effects; hydroxyl groups on the oxidized carbon nanofibers are reacted and combined with thiocyanate in vulcanized rubber powder, and hybrid filler is formed; residual active groups on the surface of the oxidized carbon fiber are combined and crosslinked with epoxy resin, so that the heat resistance of the epoxy resin is greatly improved; secondly, phenyl maleic anhydride is used as a cross-linking agent to form a three-dimensional cross-linked structure, and meanwhile, phenyl is introduced into the structure, so that the heat-resistant effect and the waterproof effect of the epoxy resin are further improved, and the adhesive prepared by taking the epoxy resin as the raw material has excellent waterproof and heat-resistant performance. The adhesive prepared by the invention has waterproof and heat-resistant effects.

The invention provides a super-hydrophobic / super-oleophylic degradable photo-thermal aerogel adsorption material and demulsification performance thereof, and belongs to the technical field of oil-water separation materials, and the super-hydrophobic / super-oleophylic degradable photo-thermal aerogel adsorption material is prepared by the following steps: (1) extracting cellulose from waste cartons and performing ultrasonic dispersion to prepare a cellulose suspension; (2) preparing a chitosan solution; (3) mixing the cellulose suspension and the chitosan solution to obtain a cellulose / chitosan composite solution, adding nano carbon black particles, glutaraldehyde and a methyltrimethoxysilane aqueous solution into the cellulose / chitosan composite solution, and stirring; (4) injecting the mixed solution into a mold, and performing directional freezing on a semiconductor refrigeration platform; and (5) performing freeze drying on the frozen sample, and then putting the frozen sample into a drying oven for cross-linking to obtain the aerogel. The aerogel is obtained by taking cellulose extracted from waste cartons and chitosan as organic frameworks, carrying out chemical crosslinking through glutaraldehyde, introducing nano carbon black particles as photo-thermal components and carrying out hydrophobic modification through methyltrimethoxysilane, and has an excellent pore structure, super-hydrophobicity-super-lipophilicity and excellent mechanical properties; the adsorbent has efficient adsorption capacity on high-viscosity crude oil; and the device can be repeatedly used and is biodegradable, so that the burden on the environment is reduced.

The present application relates to the technical field of lead-free solder paste, and more specifically, to a lead-free solder paste with low voiding rate and precision welding and a preparation method thereof, which is prepared from the following raw materials in parts by weight: 70-90 parts of tin, 1-2 parts of silver, 3-6 parts of copper, 2-5 parts of magnesium fluorosilicate, 3-6 parts of nano-carbon powder, 4-5 parts of rare earth oxide and 20-30 parts of flux. The above formula can reduce the voiding rate in the welding process, improve the wettability of the lead-free solder paste, and improve the quality and reliability of the welding points.

The invention relates to the technical field of high-corrosion-resistance stainless steel pipe processing, and discloses a high-corrosion-resistance high-molybdenum stainless steel pipe processing technology based on gradient carbide design, which comprises the following steps: applying an axial gradient magnetic field in a stainless steel pipe rolling process, and combining with dynamic strain rate matching rolling to promote molybdenum atom grain boundary migration and inhibit carbide coarsening, so as to obtain a high-molybdenum-resistance stainless steel pipe. Nano carbide smaller than or equal to 50 nm is formed on the surface layer, and submicron carbide of 200-500 nm is formed on the core part; after rolling, micro-arc oxidation and phosphonic acid group silane dipping are immediately carried out to form a self-repairing passivation film; and finally, an alternating magnetic field and pulse current are adopted for cooperative annealing, and a grain boundary molybdenum-poor region and residual stress are eliminated. Through magnetic field-chemical-thermal multi-field coupling, the material has erosion corrosion resistance of a gradient carbide structure, dynamic passive film self-repairing and low-temperature high toughness, and is suitable for long-acting protection of deep sea oil and gas pipelines.

The invention belongs to the technical field of catalysts, and particularly relates to a supported Co-based catalyst with a nano molybdenum carbide auxiliary as well as a preparation method and application of the supported Co-based catalyst. The preparation method comprises the following steps: depositing molybdenum oxide on the surface of a carrier material by adopting an atomic layer deposition method, then carrying out carburizing treatment to obtain a molybdenum carbide catalyst, depositing cobalt oxide on the surface of the molybdenum carbide catalyst by adopting the atomic layer deposition method, and then carrying out reduction treatment to obtain the supported cobalt-based catalyst with the nano molybdenum carbide assistant. According to the preparation method provided by the invention, the size of molybdenum carbide and the dispersity and valence state of cobalt are controlled by regulating and controlling the deposition times of molybdenum oxide, and the prepared catalyst has excellent catalytic activity and stability in the hydroformylation reaction of long-chain olefin with the carbon atom number being greater than or equal to 5.

The invention provides a platinum-carbon catalyst taking hollow carbon nanospheres as a carrier and a preparation method of the platinum-carbon catalyst. The method comprises the following steps: adding a polymer monomer into a nano template dispersion liquid with a uniform size; then adding a proper amount of platinum salt into the solution to obtain a mixed solution, and stirring to react for 0.5-30 hours to obtain a reaction product; and annealing the reaction product, and then removing the nano template to obtain the platinum-carbon catalyst. The obtained platinum-carbon catalyst takes the hollow carbon nanospheres as a carrier and has a larger specific surface area, the platinum catalyst is loaded on the surfaces of the carbon nanospheres and can be in better contact with an electrolyte, and the obtained catalyst has good electrochemical activity and shows excellent electro-catalytic hydrogen evolution performance and oxygen reduction performance; and the related preparation method is simple and reliable, is suitable for preparation of an electrocatalytic hydrogen evolution electrode and an oxygen reduction electrode, and has a good application prospect in the fields of proton exchange membrane electrolytic cells, hydrogen fuel cells and the like.

The invention provides a nano-carbon composite titanium aluminum lithium phosphate conductive functional material and a preparation process and application thereof, and the process adopts a mode of adding synthetic components step by step, so that the reaction is performed according to preset selectivity; according to the method, the mixing uniformity is improved, the reaction rate is controlled, the utilization rate of raw materials is improved, large-scale production and application can be achieved without complex process control, and the nanocrystallized lithium titanium aluminum phosphate conductive functional material of the in-situ composite carbon layer is synthesized under inert gas, so that the nanocrystallized lithium titanium aluminum phosphate conductive functional material is not limited to the range of being independently used as a solid electrolyte; carbon composite nanocrystallization modification endows electronic insulation titanium aluminum lithium phosphate with high electronic conductivity, the prepared nanocarbon composite titanium aluminum lithium phosphate conductive functional material and slurry thereof can be used as a modified material of a lithium ion battery and a solid or semi-solid battery electrode material, surface activity of the electrode material is passivated, side reaction of a battery material interface is reduced, and the service life of the battery is prolonged. Structural degeneration of the material in circulation is slowed down, and the overall safety of the lithium ion battery is enhanced.

The invention relates to the technical field of environment-friendly additives, and discloses an environment-friendly additive for soil pollution remediation and an application method thereof.The environment-friendly additive is prepared from 5-20 parts of nano zero-valent iron, 2-15 parts of a nano carbon material and 3-18 parts of a nano mineral composite material; 5-25 parts of biochar, 2-10 parts of microbial flora and 1-10 parts of a plant source extract; 1-8 parts of a pH responsive material; 2-10 parts of a microcapsule material; the particle size range of the nanoscale zero-valent iron is 10-100 nm, and SiO2 or C is coated on the surface of the nanoscale zero-valent iron; the nano carbon material is selected from activated carbon nanoparticles, graphene and carbon nanotubes. The carbon-coated nano zero-valent iron is adopted, so that the technical effects of improving the oxidation resistance of the material and prolonging the active life are achieved. Compared with a traditional technical scheme without coating nZVI, the problems that the composite material is prone to oxidation inactivation and insufficient in long-term repair capacity are solved, and the composite material has more stable heavy metal removal performance in a complex environment.

The invention relates to a high-temperature-resistant light stealth coating material and a preparation method thereof, and belongs to the technical field of functional materials, the high-temperature-resistant light stealth coating material comprises the following raw materials: boride, silicide, a titanate fluxing agent, metal coated carbide, a zinc oxide coated nano carbon material and a sintering aid; according to the prepared high-temperature-resistant light stealth coating material, the infrared emissivity at the wavelength of 3-5 [mu] m is 0.231-0.245, the infrared emissivity at the wavelength of 8-14 [mu] m is 0.424-0.441, the tensile bonding strength is 40.8-46.4 MPa, and the thermal shock resistance frequency is 153-167.

The invention belongs to the technical field of flame-retardant polypropylene, and particularly relates to flame-retardant polypropylene containing intumescent DOPO derivatives and a preparation method thereof.The flame-retardant polypropylene is prepared from, by mass, 100 parts of polypropylene, 15-25 parts of intumescent DOPO flame retardant shown in the formula I, 3-10 parts of linear low-density polyethylene and 2-8 parts of silane coupling agent modified glass fiber, 1-8 parts of nano calcium carbonate; the total mass part of the silane coupling agent modified glass fiber and the nano calcium carbonate is 4-10. The novel intumescent DOPO flame retardant is prepared through synthesis, has an N and P synergistic flame retardant effect, and can enable polyolefin to have a very good flame retardant effect under the condition of a relatively low addition amount. Meanwhile, a certain amount of linear low-density polyethylene, silane coupling agent modified glass fiber and nano calcium carbonate are added in a matched manner, so that the mechanical property of polypropylene is improved, and particularly the impact property is remarkably improved.

The invention discloses a compound yeast agent for anaerobic degradation of biodegradable plastics. The compound yeast agent comprises the following components in percentage by mass: 0.5-3% of fenpropathrin, 1-6% of nitrite, 1-4% of ammonium molybdate, 5-10% of PLA, 5-10% of nano starch, 3-6% of nano calcium carbonate, 1-5% of carbamide and the balance of a biodegradable resin carrier. The production method comprises the following steps: 1, dispersion treatment; 2, centralization processing; 3, carrying out structured treatment; 4, carrying out carrier implantation treatment; and 5, plasticizing and granulating. The compound yeast agent is added into the plastic, and the addition amount is 1-5%, so that the anaerobic degradation plastic is formed. According to the invention, anaerobic degradation can be regulated and controlled, and more importantly, anaerobic degradation also realizes that the degradable plastic disclosed by the invention is in a normal use condition, the plastic cannot be degraded quickly in light and oxygen environments, the aging property of the plastic is equivalent to that of a resin matrix of the plastic, and the physical and mechanical properties are ensured.

The invention discloses a device and a method for preparing single-wall and few-wall carbon nanotubes, and relates to the technical field of nano carbon materials, the device structurally comprises a heating system, a feeding system, a gas path system, a cooling system and an electrical system, the heating system comprises a medium-frequency induction furnace, an induction coil and a graphite crucible; the gas path system comprises a gas inlet; the feeding system comprises a second catalyst feeding hole and a discharging hole; wherein the feeding hole is formed above the graphite crucible, the air inlet is formed in the side surface of the medium-frequency induction furnace, and the discharging hole is formed in the other side of the medium-frequency induction furnace. The metal molten pool is used as a heat source, a steady-state heat source is provided for catalyst evaporation and single-wall / few-wall carbon nanotube growth, compared with a plasma method and an electric arc method, catalyst evaporation is more uniform and mild, the catalyst utilization rate is increased, and the single-wall / few-wall carbon nanotube growth efficiency is remarkably improved.

The invention discloses a soil stabilizer for road surface layer pouring and a preparation method thereof. The self-repairing concrete comprises the following components in percentage by weight: 30-40% of cement, 10-15% of lime, 5-10% of sodium silicate, 10-15% of bentonite, 2-5% of a polymer additive, 1-3% of a fiber reinforced material, 1-3% of nano calcium carbonate, 0.5-1% of biological enzyme, 2-4% of self-repairing microcapsules and a proper amount of water. According to the soil stabilizer, the nano calcium carbonate, the biological enzyme and the self-repairing microcapsule are added, so that the compressive strength and the water stability of the material are remarkably improved. Firstly, due to the ultrahigh specific surface area and the nanoscale particle size of nano calcium carbonate, a tighter filling effect can be formed in soil, the binding force among soil particles is enhanced, and therefore the overall compressive strength is improved. In an experiment, the compressive strength of the embodiment added with the nano calcium carbonate reaches 4.0 MPa after 28 days, the strength is doubled compared with 2.0 MPa of a reference example 1, and the remarkable effect of the nano material on the aspect of enhancing the soil structure is shown.

The invention belongs to the technical field of negative-electrode-free sodium metal batteries, and particularly discloses a negative-electrode-free sodium battery modified current collector and a preparation method and application thereof.The preparation method includes the steps that on the basis of polypyrrole preparation, transition metal salt is added, and the nitrogen doping type in polypyrrole-derived nitrogen-doped nano carbon particles is regulated and controlled. The negative-electrode-free sodium battery modified current collector prepared by the preparation method disclosed by the invention is high in relative content of N-6 and N-5 type doped nitrogen, so that the sodium affinity of a nitrogen-doped coating is improved, the nucleation over-point location of sodium metal is reduced, the reversibility of a sodium deposition / stripping reaction is improved, and the electrochemical performance of a negative-electrode-free sodium battery is further improved.

The invention provides weather-resistant anti-freezing road concrete and a preparation method thereof, and belongs to the technical field of concrete. The concrete comprises the following components: sulphoaluminate cement, Portland cement, silica fume, fly ash, modified granite gravel coarse aggregate, medium sand fine aggregate, silica fume blended fiber, silica fume blended polyacrylonitrile fiber, a composite air entraining agent, a functional modifier, a composite antifreeze agent, pre-absorbent zeolite powder and the like. The preparation method comprises the following steps: modifying granite macadam with Al (H2PO4) 3, SiO2 and methoxypolyethylene glycol triethoxysilane, and modifying with a lithium silicate aqueous solution to obtain the modified granite macadam coarse aggregate. The composite air entraining agent comprises a JRY-Q air entraining agent and sodium alpha-olefin sulfonate. The functional modifier is prepared from gas phase method spherical nano silicon dioxide and nano alpha-Al2O3. The composite antifreeze agent comprises ethylene glycol butyl ether acetate and modified calcium carbonate. The modified calcium carbonate is obtained by sequentially modifying nano calcium carbonate with calcium chloride, a KH-550 silane coupling agent and stearic acid.

The invention relates to the technical field of building decoration materials, in particular to a high-performance antibacterial mildew-proof sealant and a preparation method thereof. The sealant is prepared from the following raw materials in parts by weight: 20 to 30 parts of silane modified polyurethane, 40 to 50 parts of nano calcium carbonate, 20 to 30 parts of a plasticizer, 3 to 7 parts of a hydroxyl silane coupling agent, 0.4 to 0.8 part of a mildew preventive, 0.3 to 0.7 part of an ultraviolet light absorber, 0.3 to 0.7 part of a de-foaming agent and 0.8 to 1.2 parts of a first catalyst. The high-performance antibacterial and mildew-proof sealant has long-acting antibacterial and mildew-proof performance, and excellent mechanical performance and weather resistance of the sealant can be maintained, so that the requirements of industries such as building, medical treatment and food processing on high-performance, healthy and environment-friendly sealing materials are met; and the preparation method is simple and controllable, the production cost is relatively low, and large-scale production can be realized.

The invention provides a silicon carbon material with a multilayer coating structure and a preparation method and application thereof, and relates to the technical field of battery materials. The silicon-carbon material with the multi-layer coating structure comprises a porous carbon core body, and a first carbon layer and a second carbon layer which sequentially coat the porous carbon core body from inside to outside, and the porous carbon core body comprises porous carbon and nano silicon particles deposited on the surface and in pore channels of the porous carbon; and a conductive nano carbon filler is dispersed in the second carbon layer. The silicon carbon material with the multilayer coating structure provided by the invention is used as a lithium ion battery negative electrode material, and has excellent specific capacity, coulombic efficiency and cycle performance. The result of the embodiment shows that when the silicon carbon material with the multi-layer coating structure is applied to the lithium ion battery, the first reversible capacity is 1882-2071 mAh / g, the first coulombic efficiency is 92.6-94.1%, and the capacity retention ratio of 100 cycles is 95.3-97.7%.

The invention discloses a hot and moisture dual-cured organic silicon sealant and a preparation method thereof. The organic silicon sealant is prepared from the following raw materials: hydroxyl-terminated methyl vinyl polysiloxane, alkoxy-terminated polydimethylsiloxane, active nano calcium carbonate, fumed silica, a cross-linking agent, a catalyst and a tackifier. The organic silicon sealant organically combines the advantages of a condensation type curing system and an addition type curing system, can be quickly positioned and cured, is high in strength, good in adhesion, excellent in temperature resistance and long in storage life after being cured, and can be used for various occasions needing quick positioning and assembling.

The invention belongs to the technical field of asphalt pavement repairing materials, and particularly relates to a micro-crack self-repairing microcapsule as well as a preparation method and application thereof. The microcapsule comprises a capsule wall and a capsule core, the capsule wall is prepared from methylated melamine-formaldehyde resin and a modifier, and the modifier is selected from nano carbon powder. The microcapsule has excellent wave-absorbing and temperature-rising performance, has relatively good thermal stability and mechanical properties, and can efficiently repair pavement microcracks.

The invention discloses a nickel-based alloy composite plate and a preparation method thereof, and belongs to the technical field of nickel-based alloys, the nickel-based alloy composite plate comprises a stainless steel bottom plate and a nickel-based alloy plate, and the nickel-based alloy plate comprises, by weight, 52-58 parts of nickel powder, 17-21 parts of molybdenum powder, 8-12 parts of copper powder, 7-9 parts of boron powder, 2-3 parts of modified hafnium carbide powder, 4-7 parts of an alloy reinforcing agent and 2-3 parts of a fluxing agent. The modified hafnium carbide prepared from hafnium oxide and nano carbon powder successfully replaces metal hafnium with high cost in the traditional process; and meanwhile, the actual adding proportion of the modified hafnium carbide in the nickel-based alloy plate is greatly reduced, the cost of industrial mass production is doubly reduced from the two aspects of raw material selection and dosage control, and the economic requirement of large-scale production is better met.

The invention discloses a pesticide slow-release granule suitable for simultaneous sowing of pesticide and plant seeds. The pesticide sustained-release granule has double coating layers, the first coating layer takes a pesticide effective component A as a core and a nano calcium carbonate carrier material as a shell, and nano calcium carbonate is used for carrying out first-layer coating on a bactericide effective component through a physical adsorption method; the second coating layer is formed by mixing the first coating layer and the pesticide active ingredient B as a core and taking materials such as attapulgite as a shell. The sustained-release granule has good sustained-release performance, can stably release effective components in a long time, prolongs the pesticide effect period, reduces frequent pesticide application operation, and further improves the pesticide utilization rate.

The invention belongs to the technical field of geotechnical engineering, and particularly relates to a nanocarbon reinforced superfine cement-based blocking material as well as a preparation method and application thereof. The superfine cement-based blocking material prepared by the invention is prepared by uniformly mixing 45-50 parts of cement, 0.5-2.5 parts of a solid waste sintered active material, 0-0.05 part of a water reducing agent, 0.015-0.1 part of carbon nanotubes, 0.5-2.5 parts of a 1% solution of carbon quantum dots and 45-50 parts of water. The material has relatively low porosity and is not dispersed; the high groutability is achieved, and the material can permeate into tiny holes; and it is guaranteed that the material has high strength, the crushed rock bonding and reinforcing strength is high, and the material has wide application prospects.

The invention relates to the technical field of concrete admixtures, and discloses a nano rebound inhibitor for shotcrete and a preparation method thereof. The components, measured by weight, include 400-600 parts of nano microspheres, 400-550 parts of nano calcium carbonate, 10-30 parts of sodium carbonate, 1-10 parts of sodium aluminate, 10-30 parts of alum, 18-40 parts of polycarboxylic acid water reducer, and 0-0.5 parts of triterpenoid saponin; the nano microspheres are hydrated calcium silicate with silicon dioxide as the core material and colloid as the shell material, and the colloid is doped with a lithium source. The nano rebound inhibitor of the present application can significantly improve the state of shotcrete and greatly reduce the rebound amount of concrete, thereby further saving construction costs and accelerating construction accuracy. By utilizing the characteristics of the mineral admixture in the nano rebound inhibitor, the compactness of the concrete can be improved, and the durability of the shotcrete can be further improved.

The invention discloses a core-shell structure nano calcium carbonate antibacterial composite powder and a preparation method thereof.The preparation method comprises the steps that firstly, the surface of nano calcium carbonate is coated with a layer of amorphous TiO2 to form a CaCO3 at-TiO2 core-shell structure, then CaCO3 at-TiO2 reacts with 3-isocyanate propyl trimethoxy silane to generate a Ti-O-Si chemical bond on the surface of the CaCO3 at-TiO2 core-shell structure, and the core-shell structure nano calcium carbonate antibacterial composite powder is obtained; finally, Ag < + > is adsorbed to the surface of CaCO3 (at) TiO2 under the electrostatic action of Si-OH and is reduced into nano silver under the action of sodium citrate, and the CaCO3 (at) TiO2 (at) Ag core-shell structure antibacterial composite powder which is uniform in coating and good in dispersity is formed. The core-shell structure antibacterial composite powder disclosed by the invention shows excellent antibacterial performance in an antibacterial test on escherichia coli and staphylococcus aureus. The method provided by the invention provides a new research thought for preparation of a nano calcium carbonate core-shell structure and a nano silver antibacterial agent.

A beamformer of this invention is a beamformer configured to perform beamforming of an input electromagnetic wave and output an output electromagnetic wave, which includes a cell made of a metamaterial, and a filling material configured to fill a periphery of the cell. The metamaterial is made of a conductive organic material or a nanocarbon material. The filling material is made of a nonconductive organic material. The cell has an inductance and a capacitance. A phase of the input electromagnetic wave is changed by a change of at least one of the inductance and the capacitance.