Difuusin

Difuusin is the Japanese transliteration of diffusion, the process by which particles spread from regions of higher concentration to regions of lower concentration due to random thermal motion. In Japanese scientific literature, the native term 拡散 is used, but transliterated forms such as difuusin appear in technical contexts, including materials science, solid-state chemistry, and semiconductor processing.

The mechanism is statistical: individual particles move randomly, and the collective result is a net flux from high to low concentration. This behavior is described by Fick's laws. Fick's first law states that the diffusive flux is proportional to the negative gradient of concentration, J = -D ∇C, where D is the diffusion coefficient. Fick's second law describes how concentration evolves over time, ∂C/∂t = D ∇²C (for constant D). The diffusion coefficient depends on temperature, the diffusing species, and the medium, and it can vary with concentration and structure.

Diffusion occurs in gases, liquids, and solids. In biology, it drives gas exchange and nutrient transport across membranes. In materials science, diffusion governs dopant distribution in semiconductors and alloy formation, as well as processes such as sintering. In environmental science, diffusion influences the spread of pollutants and contaminant plumes.

Difuusin is distinct from advection and dispersion, though real systems often involve multiple transport mechanisms. Related concepts include osmosis, permeation, and diffusion-controlled reactions.