A two-stage reaction (A + B-->R, B + R-->S) is studied, where the reac
tants A and B lie initially in an array of alternating striations. The
product R is desired, and S is an unwanted byproduct. A corresponding
reaction-diffusion system in one spatial dimension is analysed in two
special cases, and comparison is made with numerical simulations of t
he reaction and diffusion in a periodic array of lamellae for realisti
c parameter values. For lamellar widths of the order of 1 mu m or less
, diffusion rapidly smears out the lamellar structure, and the yields
of R and S are nearly equal to those in a spatially homogeneous, well-
mixed system. For thicker lamellae, of around one millimetre in width,
the yields are significantly different in the lamellar case from the
well-mixed case. The differences are quantified and discussed. (C) 199
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