45results about How to "Preparation parameters are easy to control" patented technology

The present invention relates to a method for manufacturing an asymmetric polyvinlylidenefluoride (PVDF) hollow fiber membrane, which enables effective mixing of PVDF and a diluent without using separate inorganic fine powder, such as silica; in which a PVDF hollow fiber membrane is manufactured using a thermally induced phase separation method having an advantage of allowing easy obtaining of a separation membrane of consistent quality due to a key factor in controlling the phase separation in the two-substance mixture system of the polymer and the diluent being temperature, which is a manufacturing variable that is relatively simple and easy to control; in which a technique is applied for producing a temperature difference between the outer and the inner surfaces of a PVDF hollow fiber, and therefore, finally an asymmetric structure is expressed in which the inner surface side and the outer surface side of the PVDF hollow fiber have mutually different pore sizes and distributions; and which, even when an extraction process and a drawing process are applied, achieves a higher tensile strength and a larger average pore size, and thus higher porosity and water permeability than conventional hollow fiber membranes, since inorganic fine powder is not included. The asymmetric PVDF hollow fiber membrane has a pore symmetry index, defined as the ratio between the pore area on the outer surface and the pore area on the inner surface, of 0.1-0.8 and has superior water permeability and tensile strength unlike a PVDF separation membrane manufactured by the existing method.

An epitaxial growth method of a yttrium iron garnet film comprises the following steps: vacuumizing a vacuum cavity with a treated yttrium iron garnet substrate to be 8.6+ / -1*10-6 Pa, and heating the yttrium iron garnet substrate to the constant temperature which is 736 DEG C; in a heating process, feeding ozone when heating to the temperature of 250 DEG C; after heating to the temperature of 736 DEG C, maintaining air pressure of the vacuum cavity, adjusting the mass fraction of the ozone to be 40%, meanwhile insulating for half a hour, and starting a reflective high-energy electron diffraction instrument (RHEED) to adjust so as to obtain diffraction spots of a substrate; maintaining real-time and in-situ monitoring of the RHEED in the whole process, and focusing laser onto a YIG target through a lens by using a KrF excimer laser of which the wavelength is 248 nm; after growth of the film is finished, maintaining the temperature of the substrate unchanged, annealing in situ for 15 minutes, then naturally cooling the film to the temperature about 250 DEG C, stopping protective gas and cooling to the room temperature. The obtained YIG film has uniform components, is controllable in thickness and good in process repeatability, and has high preparation efficiency.

The invention discloses a lithium-ion battery composite cathode material and a preparation method thereof. The lithium-ion battery composite cathode material is composed of LMMP and a carbon material; the LMMP is phosphate in an olivine structure, and the phosphate is in stoichiometric proportion as shown in LiMn1-xMgxPO4, wherein x is not less than 0 and not more than 0.1; the LMMP is in a laminated structure, the sheet thickness is 10-30 nm, the size is 200-300 nm, and the powder tap density is 1.2-1.6g / cm<3>; and the carbon material is one or any combination of conductive carbon black and a carbon nano-tube. The preparation method comprises the following steps: solvothermal preparation of nano LMMP particles; ball-milling and mixed cladding of carbon; and annealing. Compared with the prior art, the adopted solvothermal method has the advantages of rapid reaction, low synthesis temperature and effectively controllable product appearance; and the product has uniform chemical components and uniformly distributed particles. By the subsequent ball-milling-annealing method, the nano LMMP / carbon composite material with high uniform dispersion can be obtained. The preparation method disclosed by the invention has the advantages that the technical process is simple, preparation parameters are easy to control, the repeatability is good, and the large-scale synthesis can be realized.

The invention discloses silicon with a three-dimensional hollow structure and a preparation method thereof, which belongs to the field of semiconductor material and preparation thereof. A three-dimensional structure of the silicon with the three-dimensional hollow structure of the invention has an outline that is similar to a roof, namely, a rectangular undersurface, two pairs of same sized triangles and trapezoids shaped sides, wherein, the length of the rectangular undersurface is equal to the sum of the length of a roof-shaped ridge and the width of the rectangular undersurface; particularly, when the length of the roof-shaped ridge is zero, the roof shape is degraded to the shape of a square pyramid which can also be called the shape of a pyramid. The inside part of the three-dimensional structure is hollow. Meanwhile, the invention provides a method for preparing the silicon with the three-dimensional hollow structure by a vapor deposition method. Compared with the prior art, theinvention has the advantages that raw material of the preparation is very cheap; the preparing procedures are simple and easy to be repeated; the preparation parameter is easy to control; crystallization of a generated product is good; a regular three-dimensional solid structure is provided.

The invention discloses a noble metal orientation load titanium dioxide photocatalyst and a preparation method thereof. A titanium dioxide carrier has a rutile phase structure and a uniform spherical appearance, wherein the microsphere diameter is about 10 to 16 mu m; the surface is cracked; the titanium dioxide carrier is formed by self-assembling nanowires with the length of 5 to 8 mu m and diameter of 3 to 6 mu m; and the exposed surface of each nanowire is a crystal face (110). The noble metal is one or more of platinum, gold, ruthenium, rhodium, silver and palladium; the load quantity of the noble metal is 0 to 3 percent of the mass of the titanium dioxide carrier; the noble metal exists in the form of a zero-valence simple substance; the grain size of the noble metal is 2 to 10 nm; and the noble metal is orientationally deposited on the crystal face (110) of the titanium dioxide nanowires. The noble metal load titanium dioxide material serving as an effective photocatalyst is applied to light degradation of organic pollutants in a waste water solution.

The invention discloses a zinc-copper-doped magnesium oxide nanopowder and a preparation method thereof. The zinc-copper is prepared by using magnesium acetate, zinc acetate and copper acetate as raw materials through mixing, evaporation, drying and two heat treatments. Doped magnesium oxide nanopowder, containing magnesium oxide, zinc oxide and copper oxide in the zinc copper doped magnesium oxide nanopowder, its general formula is Mg1‑xZnx‑yCuyO, wherein, 0.05≤x≤0.1,0

A high-performance graphene-supported mesoporous nickel-iron alloy electrocatalyst and a preparation method thereof belong to the technical field of graphene-based electrocatalysts. With graphene oxide as the initial support, after Sn 2+ Sensitization and Pd 2+ Activation of graphene oxide supported Pd nanoparticles Pd / GO. Ni source NiCl 2 ·6H 2 O, Fe source FeCl 2 4H 2 O and Pd / GO were dispersed in the lyotropic liquid crystal formed by the surfactant cetyl ethoxylate (Brij 58). Using dimethylamine borane (DMAB) as the reducing agent and the Pd particles on the surface of GO as the nucleation center, Brij58 was removed after the reduction reaction to obtain a graphene-supported mesoporous nickel-iron alloy electrocatalyst. The catalyst combines graphene and mesoporous nanostructures, which is conducive to the rapid transport of electrons and the increase of catalytic active sites, and has high electrocatalytic oxygen evolution performance and excellent stability.