14 results about "Surface diffusion" patented technology

The invention relates to a method of oxygen hardening of a Group IV metal, comprising the steps of: providing a workpiece of a Group IV metal in its final shape; oxidizing the Group IV metal in an oxidizing atmosphere at a first temperature using a gaseous oxidizing species having an upper temperature limit of up to 800°C for an oxidation duration of at least 10 minutes to provide a non-delaminated Group IV metal oxide on the surface of the workpiece, wherein the first temperature is in the range of 500°C and the upper temperature limit of the gaseous oxidizing species; diffusing oxygen from the non-delaminated Group IV metal oxide into the Group IV metal in an inert atmosphere at a second temperature in the range of 500°C to 800°C and at a partial pressure of the gaseous oxidizing species of up to 10"4mbar for a diffusion duration of at least 0.1 hour to provide a surface diffusion zone comprising oxygen in solid solution. In another aspect, the invention relates to a Group IV metal component comprising a material core having a core hardness and a surface hardness of at least the core hardness + 200 HV 0.025 The component is obtainable in the method of the invention.

The invention provides a method for predicting the permeability of a hydrate-containing sediment reservoir, and belongs to the technical field of unconventional oil and gas development. According to the method, the characteristics of pore size distribution, tortuosity and the like of a hydrate reservoir matrix are considered, a porous medium model formed by tortuosity capillary bundles is adopted to represent HBS on the basis of a fractal geometry theory, flow mechanisms such as a slippage effect, Knudsen diffusion and surface diffusion are comprehensively considered, and the influence of methane molecules adsorbed on a pipe wall on free gas molecule flow is considered; an HBS multi-scale permeability model is established, and a brand new HBS reservoir permeability model is deduced. By means of the model, the flow rule in the HBS reservoir and the change rule of the permeability can be predicted according to construction and geological parameters, and the blank of the existing theoretical technology is filled with the method.

The present invention discloses an analysis method for apparent permeability considering the coupling of multiple mass transfer mechanisms in coal and rock, which relates to a calculation method for the permeability of coal and rock, and solves the problem that the traditional coalbed methane permeability model ignores the influence of adsorption on the flow of coalbed methane and the inaccurate characterization of the flow law of coalbed methane. The key points of the technical solution are as follows: The nano-pores of coal and rock are equivalently divided into an adsorption layer region and an internal region, an apparent permeability equation for the adsorption layer region is established, and the apparent permeability equation for the adsorption layer region is corrected by the proportion of the adsorption layer region to obtain a first apparent permeability equation; an apparent permeability equation for the internal region is established, and the apparent permeability equation for the internal region is corrected by the proportion of the internal region to obtain a second apparent permeability equation; the first and second apparent permeability equations are superimposed to obtain a calculation model for the apparent permeability of gas in the nano-pores of coal and rock; the contribution of surface diffusion of gas in the adsorption layer to the flow flux and the influence of the coupling of multiple mass transfer mechanisms are considered.

The invention provides a low-resistivity film, a preparation method thereof and a super-atom beam auxiliary coating device. The preparation method comprises the following steps: providing a substrate; and bombarding the deposition surface of the substrate by using a super-atom beam in the process of depositing and forming the film on the surface of the substrate by sputtering a target material through an ion beam until the deposition of the film is finished. According to the method, the thin film deposition surface of the substrate is bombarded by the super-atomic beam in the deposition process, the energy of atoms on the deposition surface of the substrate can be increased by the super-atomic beam, so that the atoms are easily subjected to surface diffusion towards crystal grains with low-energy surfaces, and the low-resistivity thin film of which the crystal grain orientation is approximately consistent can be formed; in the process, the damage to the film layer can be avoided, and the compactness of the film is also improved.

This invention relates to the field of surface diffusion methods and discloses a surface treatment process for protecting the inner wall of a separation device. The process includes: placing the separation device in a vacuum chamber and introducing an active gas; opening the inlet gas path within a preset temperature zone to saturate and adsorb alloy atoms; constructing a constant-volume environment by simultaneously cutting off the gas path; calculating the pressure drop rate using an absolute pressure transmitter to characterize the flux consumed by atomic transfer to the crystal lattice; switching to a low-pressure permeation stage based on the flux consumed to remove the gas-phase barrier layer on the inner wall surface and drive atomic deep migration; and controlling the cooling process after the process to generate residual micro-compression stress. This invention utilizes the causal relationship between overall pressure evolution and surface diffusion dynamics to effectively suppress the precipitation of brittle intermetallic compounds, solve the mass transfer bottleneck in confined spaces, enhance the metallurgical bonding strength and homogeneity of the protective layer, and, in conjunction with pre-set stress, improve the service life of the separation device under strong erosion conditions.

The present invention discloses a method for predicting the leakage depth of helium in a salt cavern helium storage reservoir. First, obtain the porosity, tortuosity, and pore size distribution data of the rock sample, and then combine with the comprehensive permeability prediction method of salt rock proposed by the present invention, which considers the Knudsen effect, viscous flow, and surface diffusion effect, to calculate the comprehensive permeability of helium under the temperature and pressure conditions where the salt cavern is located; finally, according to the wellhead pressure and helium injection and production data, combined with the gas seepage equation, the leakage depth of helium during the storage period can be predicted, providing a theoretical reference for the design and construction of the helium storage reservoir and the safe and efficient storage of helium.

The invention relates to an anisotropic shale matrix apparent permeability calculation method, which comprises the following steps: directionally sampling a rock core sample in parallel bedding / vertical bedding directions, and obtaining anisotropic characteristic parameters such as TOC, aperture, surface diffusion coefficient, stress sensitivity coefficient and the like through experiments; according to the method, high-pressure mercury injection and nuclear magnetic resonance experiments are combined to represent multi-scale pore distribution and connectivity, an atomic force microscope is adopted to measure pore surface roughness, and a cone roughness element is taken as a physical model to represent roughness fractal dimension; on the basis of a three-dimensional fractal theory, factors such as multi-scale pore size distribution, connectivity, roughness, a water film, stress sensitivity and a real gas effect are integrated, transmission mechanisms such as viscous flow, Knudsen diffusion, surface diffusion and a desorption effect are coupled, and the anisotropic multi-scale micro-nano pore mass transfer model of the shale is established. Compared with a prediction model in the prior art, the anisotropic shale matrix apparent permeability calculation method provided by the invention is higher in accuracy.

The invention discloses a method for improving high-temperature oxidation resistance of an MAX phase, which comprises the following steps: introducing an oxidation film forming element A'to carry out solution treatment on A site in the MAX phase to prepare an MAX phase solid solution; the MAX-phase solid solution can generate a protective oxidation film on the surface in situ in a high-temperature oxidation environment. The solid solution A'atoms are preferentially diffused to the surface of the material in the high-temperature oxidation process to form a continuous and compact oxidation layer, the oxidation layer can effectively prevent the A atoms from diffusing to the surface to generate oxidation reaction, meanwhile, oxygen atoms can be prevented from penetrating through the oxidation layer to diffuse inwards, and therefore the high-temperature oxidation resistance of the MAX phase is remarkably improved.

The application provides a kind of deep coal seam micro-nano cross-scale pore gas permeability detection method, belongs to deep coal seam pore gas permeability detection technical field;The technical problem to be solved is to provide a kind of deep coal seam micro-nano cross-scale pore gas permeability detection method;The technical scheme adopted is: analyzing the gas transmission mechanism of micro-nano scale pore, respectively establishing: surface diffusion transmission mechanism, Knudsen diffusion transmission mechanism, slip or viscous flow transmission mechanism calculation model;And respectively establish the weighting factor of Knudsen diffusion transmission mechanism, slip or viscous flow transmission mechanism;Establish the additional pressure drop calculation model caused by end effect, finally through coupling weighting factor, end effect, establish the calculation model of deep coal seam micro-nano scale pore gas permeability;The application is applied to detect deep coal seam pore gas permeability.

This invention discloses a method for enhancing the stability of gallium nitride epitaxial growth by combining surface mobility calibration. The method involves neutralizing polarization residues on the growth layer surface through inert gas impingement and plasma activation to generate a regrowth substrate interface. Then, energy pulse-assisted control is used to alternately heat and cool the growth layer surface to obtain a regrowth layer of a predetermined thickness. The regrowth layer is then heated, and the ratio of ammonia to metal source flow rate is adjusted to generate a nitrogen-rich surface in the initial heating stage. Stress redistribution is performed in stress concentration areas to obtain a thick-layer sample. The mobility of the thick-layer sample is calibrated using a closed-loop method by comparing the mobility of a preset model with the measured surface diffusion response time to correct the timing of pulsed thermal flow period and nitrogen-rich surface formation. This invention solves the technical problems of delayed surface activity recovery, interlayer stress inhomogeneity, and rapid local dislocation propagation during the low-temperature regrowth stage, significantly improving the crystal quality and process stability of gallium nitride epitaxial layers.

The invention discloses a coal gas effective diffusion coefficient calculation method considering multiple diffusion mechanisms, which comprises the following steps: S1, collecting a target coal rock sample, carrying out related experiments, and measuring required basic parameters; s2, calculating theoretical values of volume diffusion, Knudsen diffusion and surface diffusion considering a pore structure effect and an adsorption effect, and then constructing a gas effective diffusion coefficient calculation model containing a weight coefficient; s3, calculating a sample diffusion coefficient based on an isothermal test result, and judging a main control pressure interval and a coupling mode of each diffusion mechanism; s4, performing data fitting and weight coefficient assignment; and S5, resolving the constructed effective diffusion coefficient calculation equation. According to the method provided by the invention, the dynamic transformation of a gas diffusion master control mechanism is fully considered, and the influence of the pore-fissure structure and the adsorption characteristic in the coal on the gas diffusion is brought into modeling, so that the calculation result has clear physical significance, the accurate calculation of the effective diffusion coefficient of the gas in the coal under the variable-pressure condition is realized, and the calculation efficiency is improved. And coal bed gas exploration and development can be guided.

The invention discloses a gallium nitride epitaxial stability enhancing method combined with surface mobility calibration, which comprises the following steps of: performing polarization residue neutralization treatment on the surface of a growth layer through inert gas impact and plasma activation to generate a regrowth substrate interface; and controlling the surface of the growth layer to be in a heating and cooling alternating state through energy pulse assistance so as to obtain a regrowth layer with a set thickness. And carrying out heating treatment on the regrowth layer, and adjusting the flow ratio of the ammonia gas to the metal source so as to generate a nitrogen-rich surface at the initial heating stage. And carrying out stress redistribution on the stress concentration area to obtain a thick-layer sample. And carrying out migration rate closed-loop calibration on the thick-layer sample by comparing the migration rate of the preset model with the actually measured surface diffusion response time so as to correct the pulse heat flow period and the generation time sequence of the nitrogen-rich surface. According to the method, the technical problems of surface activity recovery lag, uneven interlayer stress and rapid expansion of local dislocation in the low-temperature regrowth stage are solved, and the crystal quality and the process stability of the gallium nitride epitaxial layer are remarkably improved.

The invention discloses a plasma arc zone melting purification device and method, and relates to the technical field of metal purification, the plasma arc zone melting purification device comprises a plasma gun, a bearing assembly and a permanent magnet; the plasma gun is used for generating a plasma arc to form a melting zone on the metal to be purified; the permanent magnet is used for generating a static magnetic field in the melting zone; based on the characteristics of plasma arc smelting, strong current exists in melt, when a static magnetic field is applied around the melt, the current and the static magnetic field interact to generate Lorentz force, the melt generates strong convection under the action of the Lorentz force, melt convection is enhanced, impurities can be promoted to be diffused from the inside of the melt to the surface, the impurities are promoted to move to the surface at a higher speed, and therefore the impurities are prevented from entering the melt. Meanwhile, the thickness of the pasty area is reduced by enhancing convection, so that impurities are promoted to be discharged into the melting area from the pasty area, volatilization of the impurities and plasma reaction are promoted, and the purification efficiency is improved.

The present application discloses a method and device for calculating in-situ gas content and adsorption / free gas ratio of deep coal and rock, which relates to the field of reservoir resource potential evaluation. It includes constructing an isotope fractionation model coupled with a dual-dispersed pore structure (matrix pores and kerogen pores) and multiple gas transport mechanisms (viscous flow, Knudsen diffusion, and surface diffusion), and solving it. The cumulative desorbed gas volume and the apparent isotope value of the produced gas obtained by the solution are fitted with the measured cumulative desorbed gas volume and the apparent isotope value of the produced gas to obtain the key parameters corresponding to the optimal fitting result. According to the production capacity evaluation parameters at the initial moment corresponding to the optimal key parameters, the in-situ gas content, in-situ adsorbed gas ratio, and in-situ free gas ratio are determined. The present application calculates the in-situ gas content, in-situ adsorbed gas ratio, and in-situ free gas ratio of deep coal and rock based on an isotope fractionation model coupled with a dual-dispersed pore structure and multiple gas transport mechanisms, so as to predict the gas resource content of deep coal and rock.