The phrase "a certain diffusion" is correct and usable in written English.
It can be used when referring to a specific type or degree of diffusion in a scientific or metaphorical context.
Example: "The study focused on a certain diffusion of gases in the atmosphere that affects climate change."
Alternatives: "a specific diffusion" or "a particular diffusion".
Mr. Chatwal admitted to a certain diffusion of purpose.
Finally, English literature has enjoyed a certain diffusion abroad, not only in predominantly English-speaking countries but also in all those others where English is the first choice of study as a second language.
Therefore, we test this hypothesis by examining if the migration is explained by a parabolic curve fitting with a certain diffusion coefficient.
In this Letter, we suggest to introduce a certain diffusion effect in the substitution stage by simple sequential add-and-shift operations.
We consider a specific drug that corresponds to a certain diffusion coefficient and parameter η.
The second polymorphism we want to call attention to is the coexistence of Honest, Liar and Ignorant, which occurs e.g. at nq = 4 and nq = 5 for certain diffusion values.
The apparent diffusion coefficient (ADC) is an index that gives a rough evaluation of water diffusion in a certain region, considering diffusion as an isotropic process.
Thus, to a certain extent, the diffusion of Si atoms from substrate into the upper layer would be restrained.
The NR results indicated that even at these high molecular weights a certain amount of diffusion did occur but was confined to the first few hundred Angstroms of the interface.
No effects of film diffusion or intraparticular temperature gradients could be detected, while a certain influence of pore diffusion has to be taken into account at temperatures above 620 K.
In such cases, it seems reasonable to replace Δ with a certain type of nonlinear diffusion in (1).
