This invention provides a convenient process for manufacturing 1,3-dialkyl-2-imidazolidinones in a direct one-step reaction from industrially available alkylene carbonate, N-alkylethanolamine or 1,2-diol, which can minimize forming solid materials and be readily conducted in an indus
A non-volatile semiconductor memory device includes memory cells each having a duplicate gate structure in which a floating gate and a control gate are stacked. Each memory cell includes a semiconductor substrate of a first conductivity type; a first gate insulation film formed on the
A non-volatile semiconductor memory device includes memory cells each having a duplicate gate structure in which a floating gate and a control gate are stacked. Each memory cell includes a semiconductor substrate of a first conductivity type; a first gate insulation film formed on the
