Abstract: A multi-module fuel cell system capable of preventing backflow of purged hydrogen may include a plurality of fuel cell modules each including an air compressor, an air inlet valve, an air outlet valve, and a fuel cell stack, a discharge pipe interconnecting air outlet portions of the plurality of fuel cell modules to allow at least one of air or hydrogen discharged from the plurality of fuel cell modules to flow therethrough, and a controller configured to determine whether at least one of the plurality of fuel cell modules requires hydrogen purge, to calculate a purge pressure of a fuel cell module requiring hydrogen purge, and to calculate an air discharge pressure of a remaining fuel cell modules based on the calculated purge pressure.

Abstract: A semiconductor memory device includes a substrate; a bit-line on the substrate and extending in a first direction; first and second channel patterns on the bit-line; the second channel pattern being spaced apart from the first channel pattern in the first direction; a first word-line between the first and second channel patterns and extending in a second direction that intersects the first direction; a second word-line between the first and second channel patterns, extending in the second direction, and being spaced apart from the first word-line in the first direction; capacitors on and connected to the channel patterns; wherein the first and second channel patterns include first and second metal oxide patterns sequentially on the bit-line, each of the first and second metal oxide patterns include an amorphous metal oxide, and a composition of the first metal oxide pattern is different from a composition of the second metal oxide pattern.

Abstract: A hydrogen supply system for a fuel cell includes a fuel cell, a hydrogen supply line connected to an inlet side of a fuel-cell anode, and supplying hydrogen to the fuel cell, a pressure sensor provided on the hydrogen supply line, and measuring a pressure of the hydrogen supply line, a discharge line connected to an outlet side of the fuel-cell anode, and communicating with the outside; a discharge valve provided on the discharge line to control communication between the anode of the fuel cell and the outside, and a controller shutting off the discharge valve during an operation of the fuel cell, differently estimating an amount of gas discharged through the discharge line depending on whether choking occurs after the discharge valve is shut off, and correcting the pressure sensor based on the estimated gas discharge amount.