c	mass fraction
D	diffusion coefficient (m2/s)
Li	length of initial part of main channel (µm)
Le	exit channel length (µm)
Lt	total length of the micromixer (µm)
M	mixing index
M0	mixing index at the exit
N	number of sampling points
P	pressure drop (Pa)
Pi	pitch length (µm)
Re	Reynolds number
SAR U	split and recombine average inlet velocity (m/s)
W	width of main channel (µm)
x, y, z	Cartesian coordinates
Greek Symbols
µ	fluid dynamic viscosity (kg·m−1·s−1)
ν	fluid Kinematic viscosity (m2/s)
ρ	fluid density (kg/m3)
σ	standard deviation
Subscripts
i	sampling point or fluid component
m	optimal mixing
max	maximum value
x	axial distance