170 results about "Nucleation growth" patented technology

The invention relates to a rotary micro-liquid membrane reactor in-situ detection system for monitoring the nucleation behavior of a nano material. The reactor comprises a rotor and a stator, the base angle of the stator is 70-85 degrees, the rotating speed of the stator is 500-5000 rpm, the width of a slit is 10-500 microns, it is guaranteed that fluid does not backmix when passing through the slit, and a strong shear field is formed. A micro-negative pressure sampler is manufactured to capture nucleation particles in a high-speed shear field to enter a visual observation area, and a high-speed camera and a microscope objective lens are connected in situ, so that an instantaneous image of a nucleation process is obtained in a nano-micro scale, and a transient evolution behavior of a crystal nucleus is captured in situ. The construction of the rotary micro-liquid membrane reactor in-situ detection system solves the problems that the large-scale preparation quality is poor due to the fact that a traditional stirred tank reactor is poor in structure and micro-mixing effect and uncontrollable in material nucleation and growth, and the instantaneous phase transformation and nucleation process cannot be observed due to the fact that the reactor is closed. The obtained hydrotalcite nucleation result enriches the non-classical nucleation theory, and provides guidance for large-scale preparation of nano materials.

The invention discloses TiO2-x (F) powder, a preparation method thereof and application of the TiO2-x (F) powder in strengthening the performance of a solid hydrogen storage material, and belongs to the technical field of hydrogen storage materials and preparation of the hydrogen storage materials. The problems that an existing magnesium-based solid hydrogen storage material is high in hydrogen desorption temperature, slow in low-temperature dynamics and the like are solved. According to the preparation method, the fluorinated transition metal Ti oxide additive doped with the oxygen vacancies is prepared, electrons of Mg are captured by utilizing the strong electronegativity of F atoms on the surfaces of transition metal Ti atoms, MgF2 active catalytic species are generated in the hydrogen absorption and desorption process, and the hydrogen storage performance of MgH2 is further improved. Meanwhile, the construction of oxygen vacancies on the surface of the transition metal Ti atom can provide active sites for Mg / MgH2 nucleation growth, can greatly accelerate the flow of electrons in the hydrogen absorption / desorption process, improves the thermal / dynamic performance, and realizes the reversible hydrogen absorption / desorption of the magnesium-based hydrogen storage material at low temperature.

The invention relates to the technical field of catalyst preparation, in particular to a preparation method of a platinum-carbon catalyst with an adjustable size, which comprises the following steps: uniformly stirring and mixing an ethylene glycol solution containing H2O and an ethylene glycol solution containing potassium chloroplatinate, heating and reacting under the protection of inert gas, and cooling to room temperature after the reaction is completed; and adding a carbon carrier material into the reaction liquid, uniformly stirring, washing with water, and drying to obtain the platinum-carbon catalyst. In the invention, the polarity, viscosity and dielectric constant of an ethylene glycol solution can be changed by adding water into ethylene glycol, and the change of the properties can influence the reduction kinetics of metal ions and the nucleation growth process of particles. Therefore, under the action of the ethylene glycol reducing agent, the effect of regulating and controlling the particle size of the metal particles can be achieved only by relying on water, the method has the advantages of being simple and green and has wide application prospects, and the prepared platinum-carbon metal nano-catalyst is clean and free of pollution.

According to the high-sphericity superfine silver powder and the preparation method and application thereof, when the superfine silver powder is prepared through a chemical reduction method, a hydrothermal method is added for assistance, the crystal nucleus growth process of the silver powder is accurately controlled by adjusting parameters such as temperature and reaction time through the hydrothermal method, and the high-sphericity superfine silver powder is obtained. According to the method, the particle size and morphology are regulated and controlled, the superfine silver powder which is excellent in performance, uniform in particle size and high in sphericity degree and is used for preparing the conductive paste is prepared, and then the conductive paste prepared from the superfine silver powder with the high sphericity degree has excellent conductive performance.

The invention discloses a method for lateral epitaxial growth of a gallium nitride layer and a gallium nitride structure, and the method comprises the following steps: providing a substrate structure which comprises a substrate and a graphene layer which are stacked; etching the graphene layer to form a first window and a first graphene mask structure which are arranged at an interval; the bottom of the first window is in contact with the upper surface of the substrate, and an oxide mask structure is arranged at the bottom; etching the first graphene mask structure to form a second window to obtain a second graphene mask structure; the bottom of the second window is in contact with the upper surface of the substrate, and the second window is located around the second graphene mask structure; and growing a gallium nitride layer on the substrate at the boundary of the second graphene mask structure in a nucleation manner. According to the invention, GaN is subjected to nucleation growth in the nano-scale second window, dislocation of the substrate is blocked by the oxide mask structure and the second graphene mask structure, and a large amount of dislocation is prevented from extending to the gallium nitride layer, so that the dislocation density is greatly reduced.

This invention relates to an in-situ detection system for a rotating microliquid film reactor (MFR) for monitoring the nucleation behavior of nanomaterials. The reactor comprises a rotor and a stator, with a stator base angle of 70-85°, a rotational speed of 500-5000 rpm, and a slit width of 10-500 μm to ensure that fluid passing through the slit does not undergo backmixing and to create a strong shear field. A micro-negative pressure sampler is fabricated to capture nucleating particles within the high-speed shear field and bring them into the visible observation area. A high-speed camera and microscope objective are connected in situ, thereby acquiring instantaneous images of the nucleation process at the nanoscale and capturing the transient evolution behavior of crystal nuclei. The construction of this rotating MFR in-situ detection system solves the problems of poor micro-mixing effects and uncontrollable nucleation and growth in traditional stirred tank reactors, leading to poor quality in large-scale preparations, and the inability to observe phase transitions and instantaneous nucleation processes in a closed reactor. The obtained hydrotalcite nucleation results enrich non-classical nucleation theories and provide guidance for the large-scale preparation of nanomaterials.

The invention discloses a silicon carbide single crystal near-free-state growth device and growth method. The silicon carbide single crystal near-free-state growth device comprises a crucible cover, a crucible barrel, a neck bush and a seed crystal support, the crucible cover is positioned at the upper end of the crucible barrel and is matched with a barrel opening of the crucible barrel; the seed crystal support is positioned at the lower end of the crucible cover and is parallel to the crucible cover, the vertical section of the seed crystal support is of a transverse bow-shaped structure, and the middle position of the bow-shaped structure is sunken downwards; the vertical section of the neck bush is of an inverted-T-shaped opening structure, and the opening position at the upper end is matched with the lower end of the middle sunken position of the seed crystal support. The seed crystal support shaped like the Chinese character'gong 'can drain growth components on the edge of the crystal into a cavity on the back of the seed crystal, the edge of the crystal is in an unsaturated state, silicon carbide polycrystals cannot nucleate and grow on the edge of the crystal and the inner wall of the lining cylinder, and generation of the silicon carbide polycrystals is avoided. The near-free-state growth method ensures the stability of a growth interface, no defect proliferation occurs in the growth process, and the thickness of the silicon carbide single crystal is effectively increased.

The present invention provides a method for preparing high-stability two-dimensional black phosphorus. First, a phosphorus source and an iodine source are introduced into a reaction system for preliminary preheating and activation. After being fully activated in the raw material area of ​​the reaction system, they are slowly transferred to the crystal growth area of ​​the reaction system. The phosphorus source and the transport agent flow through the liquid to the catalyst and are fully converted in the intermediate formation area. The converted intermediate slowly moves to the crystal nucleation growth area to begin crystal nucleation and growth. After further sufficient reaction, the crystal nucleation growth point continues to extend and grow, and finally the black phosphorus crystal slowly nucleates and grows in blocks. After the crystal growth is completely cooled to room temperature, the unconverted raw materials are reused until they are finally converted into black phosphorus crystals and tail gas. The tail gas is absorbed and converted into other by-products. The use of high-temperature and high-pressure resistant pipelines can achieve efficient transportation of gaseous phosphorus, thereby extending the growth time of black phosphorus crystals and improving the growth efficiency of black phosphorus crystals.

The invention discloses a reinforcing and toughening method of a microporous copper foil, and belongs to the technical field of copper foil reinforcing and toughening, the method comprises the following steps: S1, fixing the copper foil on a tension roller, controlling the roller to operate to drive the copper foil to enter a sulfuric acid solution for pickling, and removing an oxide layer on the surface of the copper foil; s2, an electroplating solution is prepared, the electroplating solution mainly comprises sulfuric acid and copper sulfate, the sulfuric acid and the copper sulfate are mixed together according to a certain proportion, and the electroplating solution is prepared through stirring; and S3, through transmission of a tension roller, the copper foil passes through the electroplating liquid, electrochemical deposition is conducted, the copper foil serves as a cathode, the DSA coating titanium plate serves as an anode, and a layer of compact copper is deposited on the surface of the copper foil. In the invention, the copper reinforcing layer selectively performs nucleation growth on the surface of the copper foil and is not deposited in the hole. The micro-defects caused by etching or laser perforation and the like around the hole are reinforced by the reinforcing layer, so that the mechanical property is greatly improved, and the ductility is improved by 40-50%. And the improvement of the mechanical property ensures that the copper foil can be smoothly applied downstream.

The invention discloses a method for preparing Ru-RuO2 core-shell nanosheets through a gas-solid phase reaction. Carbon black with amino functionalized surface is used as a carrier,-NH2 functional groups grafted on the surface of the carbon black are used for inducing deposition, dispersion and nucleation growth of Ru metal, and the growth speed of a crystal face is changed by optimizing reduction conditions and kinetic parameters and utilizing selective adsorption of reducing gas to the Ru crystal face, so that the morphology of particles is regulated and controlled, and the Ru metal particles are obtained. And synthesizing the hexagonal Ru nanosheet without the surfactant. Ru nanosheets are partially oxidized, Ru-RuO2 core-shell nanosheet structures with different atomic layer thicknesses are further obtained, and RuO2 shells with different thicknesses can accurately regulate and control the surface strain of the catalyst. The Ru-RuO2 core-shell nanosheet has the advantages that the use of a surfactant is avoided in the synthesis process, the Ru-RuO2 core-shell nanosheet can be obtained through simple loading and calcination, the large-scale mass production can be realized, and the core-shell nanosheet can be used for efficiently catalyzing the acidic OER reaction.

The invention provides a positive electrode material precursor and a preparation method and application thereof. The preparation method comprises the following steps: a first stage: introducing a ternary metal salt solution, a complexing agent and a precipitator into a first reaction kettle, and carrying out nucleation growth to obtain a core solution; in the second stage, the core solution is transferred into a second reaction kettle, and a ternary metal salt solution, a complexing agent and a precipitator are introduced for a growth reaction until the particles grow to the target particle size in the second stage; and a third stage: keeping the introduction of each raw material solution in the second stage, and introducing the doped metal salt solution to continue the growth reaction until the growth particle size of the particles reaches the target particle size in the third stage, thereby obtaining the positive electrode material precursor. According to the invention, a reaction container transfer means is utilized, so that the doping elements are intensively doped into the shell layer of the particles in the coprecipitation process, the maximized doping effect is realized in the most efficient mode and at the lowest cost, and the electrochemical performance of the positive electrode material is remarkably improved.

The invention discloses a method for constructing a hydration kinetic model of a cemented filling body under a temperature effect. The method comprises the following steps: 1, carrying out an indoor hydration heat experiment on the cemented filling body, selecting a cementing material, tailings and water as preparation materials of the cemented filling body, and measuring hydration heat release and heat release rate of the cemented filling body; 2, verifying a hydration heat experiment result by adopting a boundary nucleation-growth model, and calculating a nucleation rate Iv and a normal growth rate G of a hydration product at different temperatures; 3, changing a constant normal growth rate into a variable normal growth rate, and introducing a nucleation rate influence factor I0 and a nucleation influence factor M0 to carry out boundary nucleation-growth model correction so as to obtain a corrected hydration kinetic model; and 4, verifying the accuracy of the corrected boundary nucleation-growth model. The method can accurately reveal macroscopic and microscopic mechanisms and association in the hydration reaction process, and has the characteristics of accurate hydration characteristic analysis and high universality.

The invention belongs to the technical field of nano materials, and particularly relates to a liquid-phase preparation method of nanoscale superfine copper powder. The nucleation growth process of the copper powder is controlled by adding a reducing agent in a segmented mode, a certain amount of dispersing agent is added in the reduction process to guarantee good dispersion of copper powder particles in a liquid phase, the situation that the nucleation number of the copper powder is reduced and the particle size is increased due to agglomeration of the copper powder in the liquid phase nucleation process is avoided, and the large-size copper powder is continuously dissolved and then separated out through reduction in each segment. And the particle size distribution is further optimized, and finally the nanoscale superfine copper powder which is good in dispersion, narrow in particle size distribution range and good in circularity is obtained.

The invention provides a cobalt tungstate and bismuth vanadate photocatalytic material as well as a preparation method and application thereof, and belongs to the technical field of material synthesis and photocatalytic application. In the presence of monoclinic-phase decahedron BiVO4, CoWO4 nanoparticles grow in situ on an electron-rich (010) crystal face of the CoWO4 nanoparticles through a hydrothermal reaction, and the cobalt tungstate and bismuth vanadate photocatalytic material is obtained. According to the cobalt tungstate and bismuth vanadate photocatalytic material, a simple hydrothermal method is adopted, in the synthesis process, a CoWO4 precursor is guided by electrostatic interaction, preferentially adsorbed and subjected to nucleation growth on the (010) crystal face of BiVO4, a compact chemical bonding interface is constructed through selective growth, the charge migration distance is effectively shortened, and the photocatalytic performance of the material is improved. The interface charge transfer resistance is reduced to the greatest extent, and the formed binary photocatalyst has excellent effects on photocatalytic hydrogen evolution and tetracycline degradation.

The invention relates to the technical field of solar cell materials, in particular to a perovskite film, a preparation method thereof and a perovskite solar cell. The preparation method of the perovskite film comprises the steps that a divalent inorganic salt aqueous solution is prepared, divalent inorganic salt in the divalent inorganic salt aqueous solution is inorganic salt corresponding to perovskite divalent cations, and the divalent inorganic salt aqueous solution contains a cationic surface active agent; performing film-forming treatment on the divalent inorganic salt aqueous solution to obtain a divalent inorganic salt film; and converting the divalent inorganic salt in the divalent inorganic salt film into organic-inorganic hybrid perovskite to obtain the perovskite film. Based on the action of the cationic surface active agent, the surface tension of the divalent inorganic salt aqueous solution is reduced, spreading is easy in the film forming process, nucleation-growth of the divalent inorganic salt is optimized, the pinhole generation risk of the divalent inorganic salt film is reduced, and finally the smooth and compact perovskite film can be obtained.

The invention discloses a novel antifreeze polypeptide with a clear structure and excellent performance and a protection method of cryopreserved cells. The core structure of the polypeptide is formed by covalently connecting two functional modules, the N end is a unit with ice crystal binding performance, the C end is a super-hydrophilic unit, and the two functional modules are bridged through a flexible linker. Experimental verification shows that the synthetic polypeptide shows excellent anti-freezing activity, can significantly inhibit nucleation, growth and recrystallization processes of ice crystals, and has particularly outstanding ice recrystallization inhibition activity. The novel antifreeze polypeptide shows excellent biocompatibility, and is suitable for low-temperature cryopreservation of cells sensitive to freezing damage and other living microbial preparations. Results show that the polypeptide can greatly improve the freeze-drying survival rate of cells and the activity of the cells after recovery, is non-toxic to the cells, and shows the potential of replacing a traditional cryoprotectant. Therefore, the method has wide application prospects in food industry, biological medicine, agricultural breeding and low-temperature preservation technologies of biological sample libraries.

The application relates to the technical field of catalysts, and discloses a nano magnesium oxide material and a preparation method and application thereof. The nano magnesium oxide material has a porous structure, wherein the particle size of the nano magnesium oxide is 20-200 nm; and the pore size of the porous structure is 5-45 nm. The classical nucleation growth process of the magnesium oxide is directionally adjusted in a weak alkaline nucleation system, and then the nano magnesium oxide with a controllable grain size distribution is obtained. The nano magnesium oxide material has good catalytic activity in the synthesis of propylene carbonate from CO2 and an epoxide under the conditions of no solvent and no auxiliary agent, and the catalyst is not deactivated after multiple uses, and has good stability.

The invention discloses a magnesium carbonate crystal prepared based on hexamethylenetetramine and a preparation method thereof, and belongs to the technical field of magnesium carbonate materials. The preparation method comprises the following steps: dissolving urea and magnesium chloride, adding hexamethylenetetramine, oscillating in water bath ultrasonic to fully react, then transferring the reaction system into a hydrothermal reaction kettle to perform hydrothermal reaction, and washing and drying a reactant to obtain magnesium carbonate crystals. According to the invention, magnesium chloride and urea are taken as raw materials, hexamethylenetetramine is taken as an additive, the nucleation-growth process is directionally regulated by the hexamethylenetetramine additive, and an optimized reaction process is adopted, so that the magnesium carbonate crystal with high purity, good crystallinity and an excellent pore structure is successfully synthesized; the prepared magnesium carbonate crystal has an optimized porous structure. According to the structure, the mass transfer efficiency is effectively improved, diffusion and transmission of substances in the material are facilitated, and the preparation method is simple and has wide application potential.

The present invention belongs to the technical field of lithium batteries, and particularly relates to a high-rate lithium / carbon monofluoride primary battery electrolyte and its application. By using sodium salts and / or potassium salts, the present invention changes the discharge mechanism of Li / CF x batteries, playing a dual role in the ion intercalation reaction mechanism and the nucleation and growth of discharge products. Compared with solvated Li + , the desolvation energy of solvated Na + with the same structure is about 30% lower, which transforms the original desolvation and intercalation mechanism involving lithium salts throughout the process into an early reaction between sodium ions and fluoride ions, reducing the reaction energy barrier of the early electrochemical reaction. At the same time, in various solvents, the Stokes radius of K + is smaller than that of Li + , which means that the diffusion rate of K + is faster, which can not only reduce polarization but also increase the ion intercalation rate, achieving good rate performance. Finally, the present invention realizes an increase in the discharge specific capacity and specific power of the battery, without sacrificing the specific capacity and specific power due to the increase in the mass of non-active substances.

The application provides an inorganic doped electrochromic fabric and a preparation method thereof. The flexible conductive fabric is first treated with an ammonium sulfate solution for hydrophilic treatment to obtain a pretreated fabric; then a tungsten chloride anhydrous ethanol solution is prepared, and molybdenum pentachloride powder is added to prepare a precursor solution; finally, the pretreated fabric is placed in the precursor solution for high-temperature reaction, and the inorganic doped electrochromic fabric is obtained after the reaction is completed. The flexible conductive fabric is treated with the ammonium sulfate solution, functional treatment is realized, and the surface activity is improved, so that the chemical bonding between the fabric and the electrochromic film is promoted; the molybdenum pentachloride is selected as the precursor, which provides a site for the nucleation and growth of WO3 on the surface of the fabric, so that a stable WO3 and MoO3 composite film is formed, the film serves as an electrochromic layer, the fabric has excellent electrical, optical and mechanical properties, has a fast optical response time and a high coloring efficiency, and can be applied to the fields of smart clothes and implantable display.

The application discloses preparation of one-dimensional rare earth metal-organic framework, one-dimensional rare earth metal-organic framework loaded transition metal-organic framework material and preparation and application, relates to the technical field of one-dimensional nanowire RE-MOF material preparation and double-MOF composite core-shell structure preparation, and a preparation method comprises the following steps: synthesizing a series of RE-MOF precursor one-dimensional nanowires by a solvent thermal method; at room temperature, in a methanol solvent system, PVP is used as an inducer to promote Co 2+ Deposition and enrichment on the surface of the RE-MOF, and then nucleation and growth of a uniform TM-MOF shell layer are formed by the coordination of 2-methyl imidazole and Co 2+ , thereby obtaining a core-shell structure one-dimensional nanowire Co-MOF@RE-MOF material. Finally, the prepared series of core-shell structure one-dimensional nanowire materials are subjected to calcination treatment in an argon atmosphere, and a multi-component composite wave-absorbing material with good wave-absorbing performance is obtained.

The invention provides a preparation method of nano vanadium dioxide. According to the preparation method, a sol-gel method and a micro-scale confinement space reaction are combined, the sol-gel method can realize uniform mixing of raw materials in a liquid phase, a stable sol system is formed through hydrolysis and condensation chemical reactions, and the micro-scale confinement space reaction limits nucleation and growth processes through a micro-nano-scale physical space, so that the micro-scale confinement space reaction is formed. According to the preparation method, the material is subjected to'guiding 'growth, vanadium ion form transformation and ultrafine particle nucleation growth can be realized in one step, preparation of nano powder with given structural characteristics is realized, meanwhile, the phenomenon of product agglomeration is avoided, and the powder prepared by the process method is relatively high in particle size controllability and good in dispersity.

The present invention discloses a test method for the consistency of precursor material conversion and amplification, and the specific process is that in the experimental stage, a laser particle counter is used to measure the number of crystal nucleus particles per unit volume in the precursor slurry sample in the nucleation stage of the crystallization reaction, which is marked as n1, and the nucleation time is t1; in the conversion and amplification stage, a laser particle counter is used to measure the number of crystal nucleus particles per unit volume in the precursor slurry sample in the nucleation stage of the crystallization reaction, which is marked as n, and when the relative deviation of n and n1 is within ±10%, the time at this moment is the actual nucleation time of the conversion and amplification stage, and the pH corresponding to the nucleation stage is adjusted to the pH corresponding to the crystal nucleus growth stage under this nucleation time, and the crystal nucleus production stops feeding when the required particle size is reached, and the product conversion and amplification is successful. The present invention has the advantages of high efficiency, low cost, and high accuracy.

The invention discloses a two-dimensional carbon plate loaded nanocrystalline composite material and a preparation method and application thereof, and the preparation method comprises the following steps: S1, preparing a solution, dissolving a template agent, a carbon-containing anion agent and a metal salt in a solvent, and stirring to fully dissolve to obtain a mixed solution; s2, placing the mixed solution in a high-pressure reaction kettle by a one-pot method, converting a carbon-containing component in the solution into a two-dimensional carbon plate under a high-temperature condition, performing nucleation growth on metal ions and anions in the solution on the surface of the two-dimensional carbon plate, and after the reaction is finished, separating a solid to obtain a precursor; and S3, calcining: placing the precursor in an atmosphere furnace, adding an active substance into the atmosphere furnace or introducing active gas into the atmosphere furnace, and calcining in a protective gas atmosphere to obtain the two-dimensional carbon plate loaded nanocrystalline composite material. The two-dimensional carbon plate-loaded nanocrystalline composite material has a uniform nanoscale grain size, and has relatively high specific capacity when being used as a lithium ion battery negative electrode material.

This invention discloses a retarder for magnesium silicate cementitious materials and its preparation and application methods, belonging to the field of green building materials technology. The retarder of this invention is composed of sodium hexametaphosphate, citric acid, and tartaric acid in a mass ratio of (1-3):(2-4):(0.5-2). The retarder of this invention forms a three-level gradient synergistic retarding effect by using sodium hexametaphosphate to inhibit the rapid dissolution of active magnesium oxide, citric acid to chelate and regulate the magnesium ion concentration in the liquid phase, and tartaric acid to inhibit the nucleation and growth of hydration products, covering the entire hydration process of magnesium silicate cementitious materials. This invention also discloses the preparation and application methods of this retarder. Compared with existing technologies, the retarder of this invention can significantly extend the setting time of magnesium silicate cementitious materials while maximizing the preservation of their mechanical properties and improving slurry fluidity. Furthermore, the raw materials are widely available, the preparation process is simple, and the cost is controllable, showing good prospects for industrial application.

The invention relates to a method for one-step synthesis of high-quality stannous oxide through intermittent ultrasonic reinforcement, and belongs to the technical field of semiconductor material preparation. The preparation method comprises the following steps: dropwise adding a sodium hydroxide aqueous solution into a stannous chloride aqueous solution at room temperature under a stirring condition until the pH value is 12.5-13.5 to form a mixed solution system; applying intermittent ultrasonic waves to the mixed solution system for intermittent ultrasonic treatment to induce direct nucleation and growth of stannous oxide and synchronous removal of chlorine impurities, carrying out solid-liquid separation, and drying the solid to obtain the low-chlorine fine-particle-size stannous oxide. According to the method, through the work-stop periodic effect of intermittent ultrasound, dynamic conditions are provided for diffusion and desorption of chloride ions while nucleation and growth regulation are promoted through cavitation, cooperative regulation of particle size refinement and deep dechlorination of stannous oxide is achieved, a high-temperature step or repeated washing is not needed, the process is simple and efficient, the conditions are mild, and the method is suitable for industrial production. And controllable preparation of the high-performance stannous oxide material can be realized.

The utility model discloses a gradient regulation type nanometer active silicon particle size synthesis reaction device, which relates to the technical field of nanometer active silicon particle size synthesis reaction devices and comprises an active silicon reaction kettle, a cavity is arranged in the active silicon reaction kettle, and an electric heating plate is sleeved in the cavity. The inner wall of the active silicon reaction kettle is fixedly connected with an ultrasonic assembly. According to the gradient regulation and control type nano active silicon particle size synthesis reaction device, through cooperative coupling of the electric heating plate and the ultrasonic assembly, the ultrasonic generator drives the multiple ultrasonic transducers which are symmetrically distributed to form a uniform cavitation field, and meanwhile the electric heating plate dynamically adjusts a temperature field based on a control panel instruction; space-time matching optimization of a temperature-cavitation dual-energy field is achieved, reaction nonuniformity caused by energy field separation of traditional equipment is effectively overcome, ultrasonic hot spots in the reaction kettle are eliminated through ultrasonic transducers which are arranged on a connecting rod in an axial symmetry mode, nano silicon particle nucleation growth kinetics are controllable, and the particle size standard deviation is reduced.

The embodiment of the application relates to a method for preparing perovskite quantum dots assisted by supercritical carbon dioxide, and belongs to the technical field of perovskite quantum dots. The method solves the problems of complex process of hot injection method, large amount of anti-solvent required by ligand assisted precipitation method and difficult size control. The specific steps include: 1) dissolving lead halide and ligand 1 in polar solvent 1 to form precursor solution A; 2) dissolving cesium halide and ligand 2 in polar solvent 2 to form solution B; 3) premixing solution A and supercritical carbon dioxide to be homogeneous; 4) adding anti-solvent 3 into the reaction kettle and introducing the homogeneous phase of solution A and supercritical carbon dioxide; 5) rapidly injecting solution B for reaction, and releasing pressure after crystal nucleation and growth; 6) collecting and purifying the product. The method is green and efficient, and the prepared perovskite quantum dots are suitable for the fields of optoelectronic devices, display and lighting, etc.

A novel normal-temperature normal-pressure imine-linked covalent organic framework rapid preparation method relates to the technical field of covalent organic framework materials, and comprises the following steps: 1) dissolving an aldehyde group monomer and a fatty amine regulator in a tetrahydrofuran and toluene composite solvent; 2) dissolving an amino monomer in a composite solvent of tetrahydrofuran and toluene; and 3) mixing the solution obtained in the step 1), the solution obtained in the step 2) and an acetic acid aqueous solution for reaction, and then washing and drying to obtain the COFs material. The COFs are prepared in a simpler mode based on a new nucleation-growth mechanism, and the technical problems that in the prior art, COFs preparation means are tedious, the product crystallinity is poor, and batch preparation is difficult can be solved. According to the method, the synthesis cost and time are remarkably reduced, the yield and crystallinity of the COFs are improved, and a foundation is laid for industrial application of the COFs.

This invention discloses a one-dimensional WS2 / WSe2 heterojunction material, its preparation method, and its applications, belonging to the field of nanomaterials technology. The one-dimensional WS2 / WSe2 heterojunction material is a one-dimensional structural material composed of alternating WS2 nanoribbons and WSe2 nanoribbons arranged along its width direction. Furthermore, this invention proposes a method for preparing the one-dimensional WS2 / WSe2 heterojunction material, comprising: arranging a WS2 source and a WSe2 source separately in a reaction apparatus, and placing a growth substrate loaded with salt halides in the nucleation growth region; heating to the growth temperature under a protective atmosphere to allow the WS2 source and WSe2 source to react sequentially; and obtaining the one-dimensional WS2 / WSe2 heterojunction material through catalytic induction of the salt halide by sequentially switching the effective supply of the WS2 source and WSe2 source. The one-dimensional WS2 / WSe2 heterojunction material proposed in this invention exhibits high crystallinity and a clear heterojunction interface.