Abstract: A nonvolatile memory device includes a memory block including a first structure formed on a substrate and a second structure formed on the first structure. An erase method of the nonvolatile memory device includes applying a word line erase voltage to first normal word lines of the first structure and second normal word lines of the second structure, and applying a junction word line erase voltage smaller than the word line erase voltage to at least one of a first junction word line of the first structure and a second junction word line of the second structure. The first junction word line is a word line adjacent to the second structure from among word lines of the first structure, and the second junction word line is a word line adjacent to the first structure from among word lines of the second structure.

Abstract: A nonvolatile memory device includes a memory block including a first structure formed on a substrate and a second structure formed on the first structure. An erase method of the nonvolatile memory device includes applying a word line erase voltage to first normal word lines of the first structure and second normal word lines of the second structure, and applying a junction word line erase voltage smaller than the word line erase voltage to at least one of a first junction word line of the first structure and a second junction word line of the second structure. The first junction word line is a word line adjacent to the second structure from among word lines of the first structure, and the second junction word line is a word line adjacent to the first structure from among word lines of the second structure.

Abstract: The present disclosure relates to an engine valve device including: engine valves; valve guides configured to guide a reciprocating motion of the engine valves; and stem seals fitting on one end of each of the valve guides and circumferentially covering the engine valves, in which the engine valves have micro-machined oil ports on the surfaces surrounded by the valve guides or the stem seals.

Abstract: The present disclosure relates to an engine valve device including: engine valves; valve guides configured to guide a reciprocating motion of the engine valves; and stem seals fitting on one end of each of the valve guides and circumferentially covering the engine valves, in which the engine valves have micro-machined oil ports on the surfaces surrounded by the valve guides or the stem seals.