10 results about "Spontaneous nucleation" patented technology

The invention discloses a crystal growth method for avoiding formation of a gallium oxide polycrystal shoulder, and belongs to the technical field of crystal growth. The length of the slit on the surface of the mold is designed to be not more than one third of the length of the mold, and melt supply is strictly limited in a local area of the slit in a seeding stage, so that accurate starting of single crystals is realized; and then, in a crystal lateral expansion stage, actively regulating and controlling the interval between the upper surface of the mold and a crystal growth interface, so that a melt layer in the interval is used as a dynamic and expandable raw material supply channel. Therefore, the technical prejudice that a traditional edge-defined film-fed method depends on full-length solid slit feeding penetrating through a mold is broken through, a melt exposure area is reduced to be near a growth interface, spontaneous nucleation of a melt in a non-target area is fundamentally inhibited, formation of a polycrystal shoulder (square shoulder) is effectively avoided, raw material volatilization is remarkably reduced, thermal field uniformity is improved, and the method is suitable for large-scale production. And the crystal quality, the growth stability and the process efficiency are improved.

This invention relates to a crystal growth apparatus, method, and application based on thermal convection mass transfer, belonging to the field of crystal material preparation technology. The invention aims to solve the problems of spontaneous nucleation, secondary nucleation, and the intrusion of impurities into the growth zone leading to decreased crystal quality, as well as poor interfacial stability caused by mechanical stirring, in existing single crystal preparation processes. The method involves: 1. Establishing a temperature field and gradient; 2. Adding crystal raw materials and growth media to the dissolution zone reactor, ensuring the crystal raw materials form a saturated solution in the dissolution zone reactor with some solid raw material remaining, suspending the seed crystal; 3. Not adding crystal raw materials to the high-temperature zone reactor; 4. Cooling after growth to obtain a single crystal. This invention reduces the probability of microcrystals / clusters entering the growth zone, and reduces interfacial disturbance and further suppresses the intrusion of impurities into the growth zone without introducing mechanical stirring, resulting in higher crystal quality.

The application relates to a large-size orthorhombic phase bromine lead cesium single crystal and a solution growth method and application thereof, and belongs to the technical field of crystal materials. The application comprises the following steps: (1) mixing water and dimethyl sulfoxide uniformly, adding cesium bromide and lead bromide to obtain a bromine lead cesium solution; (2) overheating the bromine lead cesium solution at 70-80 DEG C for 24-48h to obtain a bromine lead cesium growth solution; and (3) growing the bromine lead cesium seed in the bromine lead cesium growth solution or spontaneously nucleating and growing under a sealed condition to obtain a large-size orthorhombic phase bromine lead cesium single crystal. The application uses a mixed solution of water and dimethyl sulfoxide as a solvent of cesium bromide and lead bromide for the first time, lets water participate in the growth of the bromine lead cesium crystal, changes the inverse temperature crystallization property of the CsPbBr3 crystal, changes the solubility of the CsPbBr3 crystal from an inverse temperature curve into a positive temperature curve, realizes the temperature-reducing controlled growth of the crystal, and effectively avoids the generation of other by-products of the bromine lead cesium.

The invention discloses a homogeneous and heterogeneous seed crystal epitaxial growth method and application of a Pb-based hybrid perovskite MAPbBr3-nCln crystal, and relates to the technical field of perovskite crystal growth. The method comprises the following steps: obtaining homogeneous seed crystals or heterogeneous seed crystals; the preparation method comprises the following steps: dissolving MABr, PbBr2 and PbCl2 in an organic solvent, and filtering to obtain a precursor solution; and sealing the precursor solution, preserving heat in a water bath at 35-42 DEG C for 6-24 hours, then putting the homogeneous seed crystal or the heterogeneous seed crystal into the precursor solution, then partially dissolving the homogeneous seed crystal or the heterogeneous seed crystal at 35-42 DEG C, then heating to 55-60 DEG C from 35-42 DEG C at a speed of 2-3 DEG C / d, and keeping the constant temperature at 55-60 DEG C for 12-24 hours, thereby obtaining the Pb-based hybrid perovskite MAPbBr3-nCln crystal through epitaxial growth of the seed crystal. By introducing the seed crystal, the problem of excessive nucleation quantity in spontaneous nucleation is solved, so that the nucleation quantity is reduced; and the size and the crystallization quality of the MAPbBr3-nCln crystal can be improved.

The application discloses a method for preparing 2-chloro-4-(1H-pyrazol-3-yl)benzonitrile and relates to the technical field of 2-chloro-4-(1H-pyrazol-3-yl)benzonitrile. A clear hot-solvent pretreatment liquid is formed; a homogeneous supersaturated mother liquor is obtained; a high-activity primary crystal seed suspension is constructed; the remaining main body liquid stream of the supersaturated mother liquor is subjected to nonlinear programmed cooling pretreatment, so that the remaining main body liquid stream enters a phase diagram metastable zone but maintains a stable state without spontaneous nucleation, and a metastable nucleation precursor liquid is formed; and high-purity and uniform-crystal 2-chloro-4-(1H-pyrazol-3-yl)benzonitrile finished products are prepared. The application can extract an absolutely homogeneous and extremely low-impurity pretreatment liquid, and significantly improves the purity standard and optical transmittance of a subsequent crystallization mother liquor.

The invention relates to a dynamic evolution simulation method and system for an aluminum alloy high-solid-phase rheo-die-casting microstructure, and belongs to the technical field of aluminum alloy material solidification numerical simulation and calculation material science. The simulation method comprises the following steps: (1) establishing a rheo-die-casting whole-process model, and constructing a control equation set of a coupling phase field and a solute field by adopting a quantitative phase field model framework; a macroscopic temperature field is obtained through multi-scale parameters, thermodynamic parameters are coupled and called in real time, secondary alpha2-Al phase nucleation in the second-stage rheology die-casting forming process is simulated through a spontaneous nucleation calculation method, and numerical solution and visualization are conducted; (2) setting boundary conditions; (3) solving an equation; and (4) data processing. The invention also discloses a simulation system. According to the method, whole-process dynamic simulation is achieved for the first time, macroscopic-to-mesoscopic multi-scale thermodynamic multi-physics field accurate coupling is achieved, and the method is high in engineering applicability and suitable for binary alloy.

This invention relates to the field of water treatment technology, specifically to a sludge phosphorus release and phosphorus crystallization recovery device, comprising a phosphorus release mechanism and a phosphorus crystallization recovery mechanism. The phosphorus release mechanism includes a sludge thickening unit, a sludge breaking component, and a sludge dewatering unit; the sludge breaking component includes a sludge breaking unit and a pH adjustment unit; the phosphorus crystallization recovery mechanism includes an outer shell, a middle shell, an inner shell, a flow-pushing and stirring component, a baffle vortex component, a modular vortex component, an inclined plate component, and a micro-nano aeration disc. The outer shell, middle shell, and inner shell combine to form a unique circulation channel. Combined with the micro-nano aeration disc, small crystal particles enter the circulation channel as seed crystals, providing readily available nucleation sites for the solution, reducing the critical supersaturation required to form new crystal nuclei, reducing the probability of spontaneous nucleation, inhibiting the formation of irregular dendritic or needle-like crystals, and promoting the formation of denser, more uniform prismatic or plate-like large crystal particles, thus achieving efficient phosphorus release and phosphorus crystallization recovery.

The application provides a Li + Doped halide scintillation crystal and preparation method thereof, the chemical formula of the scintillation crystal is Cs 1‑x Cu2I3:xLi, wherein the value range of x is 0.001<=x<=0.1. CuI powder, CsI powder and LiI powder are dosed in a molar ratio of 2:(1-x):x under an inert atmosphere, and after being fully mixed, the raw material powder is used to grow the Cs 1‑x Cu2I3:xLi one-dimensional perovskite structure metal halide scintillation crystal by a spontaneous nucleation crucible descending method. The crystal can emit a broadband yellow light of 400-800 nm after excitation, and the intensity is much higher than that of the original pure component crystal. Due to the existence of Li + , the application range is further expanded from the original X / gamma ray detection to the neutron detection field.

The application discloses a production process of anti-condensation and anti-caking taurine crystals, which comprises the following steps: (1) a homogeneous feed liquid with taurine concentration of 10-15 wt% and temperature of 35-50 DEG C is introduced into a flash evaporator to perform flash cooling to form a low supersaturation solution with temperature of 25-35 DEG C; (2) the low supersaturation solution is introduced into the top of a plug flow crystallizer, and the crystals spontaneously nucleate and grow in the descending process of the plug flow crystallizer, and slurry with complete supersaturation release is obtained at the bottom outlet; (3) the slurry is introduced into a thickener, and after the solid content is increased to 30-40%, filtration is performed, and the obtained solid is dried to obtain the taurine crystals. The taurine crystals obtained by the production process have the advantages of less defects, smooth crystal surface, narrow particle size distribution, small aspect ratio, good fluidity, and greatly improved anti-condensation and anti-caking performances.

The application discloses a crystal growth method for avoiding polycrystalline shoulder formation of gallium oxide, and belongs to the technical field of crystal growth. The length of a slit on the surface of a mold is designed to be less than one third of the length of the mold, the supply of melt is strictly limited to the local area of the slit in the seeding stage, and the accurate starting of a single crystal is realized. Then, in the lateral expansion stage of the crystal, the interval between the upper surface of the mold and the growth interface of the crystal is actively controlled, and the melt layer in the interval is used as a dynamic and expandable raw material supply channel. Therefore, the technical prejudice of the traditional guide mold method relying on the full-length entity slit supply of the mold is broken, the melt exposure area is reduced to the vicinity of the growth interface, the spontaneous nucleation of the melt in the non-target area is fundamentally inhibited, the formation of the polycrystalline shoulder (flat shoulder) is effectively avoided, the raw material volatilization is significantly reduced, the thermal field uniformity is improved, and the crystal quality, the growth stability and the process efficiency are improved.