9 results about "Diffusion flux" patented technology

The invention discloses a system and a method for measuring the release flux of methane in a water body, and belongs to the technical field of measurement of the release flux of methane gas in the water body. When the diffusion flux is measured, the box body is placed on the liquid level of the water body in a floating manner, and the partition plate is arranged below the first opening of the box body at the interval of the first preset distance, so that methane gas released in the form of bubbles in the water body below the partition plate can be prevented from entering the accommodating cavity, and the interference of bubble release on the measurement result can be reduced; the determination accuracy of the diffusion flux is improved. When the bubble flux is measured, the cover body covers the sediment at the bottom of the water body below the box body, and the methane gas released by the sediment is collected by the gas collection container below the liquid level, so that the probability that bubbles are dissolved in the water body in the floating process can be reduced, and the measurement accuracy of the bubble flux is improved.

This invention discloses a method for predicting the high-temperature degradation of resistance in micro-copper pillar bump interconnects, comprising: establishing a relationship between the net flux of Ni atoms and the thickness variation of the Ni-Cu-Sn compound layer based on the thermal diffusion flux of Ni atoms; establishing a relationship between the net flux of Cu atoms and the thickness variations of the Cu6Sn5 and Cu3Sn layers based on the thermal diffusion flux of Cu atoms; and establishing a relationship between the Ni-Cu-Sn compound layer and the Cu6Sn layer based on these thickness variation relationships. s This invention provides an effective solution for predicting the high-temperature degradation of Ni-plated copper pillar bump interconnect resistors, significantly reducing or avoiding the time and economic costs associated with numerous lifetime and failure analysis tests. It establishes a high-temperature growth model for the Cu3Sn layer and its thickness; a high-temperature consumption model for the Cu pads, Sn solder, and Ni layer based on the thickness high-temperature growth model; and a high-temperature degradation model for the resistor based on the thickness high-temperature growth model and the thickness high-temperature consumption model.

The application discloses a method for determining and distinguishing methane bubble flux and diffusion flux released by water bodies, and belongs to the field of methane flux determination in environmental water bodies, and comprises the following steps: determining the gas content of CH4 and N2O in the gas after the water body at a sampling point and surrounding atmosphere are shaken together and in the surrounding atmosphere of the water body at the sampling point, calculating the gas concentration of CH4 and N2O in the water body when the water body and the surrounding atmosphere are balanced and in the water body at the actual sampling point; determining the release flux of N2O and the total release flux of CH4 in the water body; calculating and comparing the gas mass transfer coefficients of diffusion type CH4 and total CH4; and calculating the CH4 diffusion and bubble flux. The application utilizes N2O to calculate the CH4 diffusion flux, realizes the rapid distinction of bubble type and diffusion type CH4 of water bodies, can collect and determine CH4 gas on a large scale in multiple environments, and solves the problems that CH4 determination is easily affected by the environment, time-consuming is relatively long, and it is difficult to capture occasional bubble events.

The invention discloses a method for measuring and distinguishing bubbling flux and diffusion flux of methane released by a water body, which belongs to the field of methane flux measurement in environmental water bodies and comprises the following steps: measuring the gas content of CH4 and N2O in gas generated after the water body at a sampling point and the surrounding atmosphere are oscillated together and in the surrounding atmosphere of the water body at the sampling point; calculating the gas concentrations of CH4 and N2O in the water body when the water body at the sampling point and the surrounding atmosphere are balanced and in the water body at the actual sampling point; measuring the release flux of N2O and the total release flux of CH4 in the water body; calculating and comparing the gas mass transfer coefficients of the diffusion type CH4 and the total CH4; and calculating the CH4 diffusion and bubbling flux. According to the method, N2O is used for calculating the diffusion flux of CH4, rapid distinguishing of bubbling type CH4 and diffusion type CH4 in a water body is achieved, CH4 gas can be collected and measured in a large scale in multiple environments, and the problems that CH4 measurement is prone to being affected by the environment, consumed time is long, and accidental bubbling events are difficult to capture are solved.

The invention relates to the technical field of continuous casting, in particular to a casting method of an aluminum alloy slab ingot for a power lithium battery, which comprises the following steps: collecting crystallizer temperature difference to construct a thermal gradient sequence, identifying temperature drop rate abnormity and establishing a concentration migration area, calculating diffusion flux to obtain an element migration trend, judging dissolution rate change and delimiting a material supplementing window. And the stirring linkage rate is set by combining the dilution section mark. According to the method, a thermal gradient evolution sequence is constructed through multi-point temperature difference, local thermal disturbance is recognized and the alloy element migration trend is tracked by combining temperature drop rate, side wall temperature and liquid level layer thickness change, diffusion flux in a specific temperature zone is matched, dissolution rate change is judged by combining material flow temperature difference and concentration fluctuation, and a short-time material supplementing response interval is delimited; and through linkage dilution section identification and stirring speed setting, the feeding action and the melt state are synchronously adjusted, component distribution balance and crystal structure uniformity are enhanced, and the risks of section segregation, hardness fluctuation and internal structure crack defects are reduced.

The invention discloses a low-permeability reservoir carbon dioxide flooding numerical simulation method based on Maxwell-Stefan cross diffusion, and belongs to the technical field of reservoir numerical simulation and recovery efficiency improvement. Comprising the following steps: establishing a mass conservation equation of each component based on an oil reservoir thermodynamic field, a rock physical property field, an effective diffusion coefficient matrix and reaction kinetic parameters; a diffusion flux item is expressed by a generalized Fick law based on a Maxwell-Stefan theory so as to describe a multi-component cross diffusion effect; a reaction source convergence item is determined by a COand crude oil reversible miscible phase kinetic model so as to describe a miscible phase and split phase dynamic process; sequentially executing a diffusion transmission step and a chemical reaction step for solving by adopting an operator splitting method to obtain an updated concentration field, and synchronously updating the thermodynamic field, the rock physical property field, the reaction kinetic parameters and the effective diffusion coefficient matrix; repeatedly iterating until each field and parameter change meet a convergence condition, and completing simulation of each chemical component concentration field; according to the method, the physical simplification defect in low-permeability simulation is overcome, and high-precision prediction of the displacement process is achieved.

The utility model discloses an embodiment relates to a kind of buffer tanks for large diffusion flow membrane filter integrity test, upper oval head is arranged above the buffer tank for large diffusion flow membrane filter integrity test;Lower oval head is arranged below the buffer tank for large diffusion flow membrane filter integrity test;Tank body is arranged between upper oval head and lower oval head head;The length-diameter ratio of buffer tank is 1:1 to 20:1, buffer tank plays the role of gas uniform buffering, stable test pressure, improves the accuracy and reliability of test, solves the technical problem of the problem that when membrane filter is tested by automatic filter integrity tester in prior art, because diffusion flow is too large, and the upstream volume of membrane filter is small, so that the gas pressure in upstream volume drops too fast during test, and cannot be successfully tested.

The application provides a numerical calculation method for simulating solid fuel thermochemical conversion, belonging to the field of thermochemistry, and more specifically, the method comprises the following steps: constructing a geometric model containing solid fuel and a gas environment; establishing control equations for the constructed geometric model; defining a chemical reaction kinetics model of the solid fuel, and determining source terms of the control equations according to the chemical reaction kinetics model, so as to obtain actual control equations; based on the Knudsen diffusion mechanism, the diffusion fluxes of different gases in the actual control equations are corrected to obtain corrected actual control equations; and the thermochemical conversion process is calculated according to the constructed geometric model and the corrected actual control equations. The application can avoid the local over-temperature collapse of the calculation model caused by the rapid concentration of combustible gas and oxidant or gasification agent to a higher temperature area, thereby making up for the defects of the existing numerical calculation method for solid fuel thermochemical conversion.

The invention discloses a rapid wall surface simulation method of a lattice point type unstructured grid finite volume method, and belongs to the technical field of calculation fluid wall surface simulation. According to the method, wall surface flow flux calculation logic is simplified, and the boundary facet center gradient is calculated through original grid physical quantity information projection; in the process of solving the convection flux and the diffusion flux, through calculation modes such as momentum interpolation and boundary node physical quantity interpolation, in combination with an iterative solution and under-relaxation processing mode, rapid solving of the wall surface flow flux is achieved, so that the time consumption of overall simulation calculation is shortened, the solving efficiency is improved, and the calculation cost in engineering application is reduced.