Abstract: An oil circulation device for an internal combustion engine includes an oil pan, a partition, and a communication groove. The oil pan is disposed below a cylinder block and includes a bottom wall and a sidewall to define a recessed portion that opens upward. The partition extends upward from the bottom wall so as to have a protruding end and divide the recessed portion into a first recessed portion and a second recessed portion. The communication groove extends downward from the protruding end of the partition in a thickness direction of the partition to connect the first recessed portion and the second recessed portion.

Abstract: An oil circulation device for an internal combustion engine includes an oil pan, a partition, and a communication groove. The oil pan is disposed below a cylinder block and includes a bottom wall and a sidewall to define a recessed portion that opens upward. The partition extends upward from the bottom wall so as to have a protruding end and divide the recessed portion into a first recessed portion and a second recessed portion. The communication groove extends downward from the protruding end of the partition in a thickness direction of the partition to connect the first recessed portion and the second recessed portion.

Abstract: Even if it is impossible to image a pattern surface of a wafer that is placed with its down on a wafer table with visible light, a wafer pattern imaging apparatus is able to image the pattern surface (the obverse) from the reverse of the wafer with light transmitted through the wafer. The obverse of the wafer, made of silicon, is attached to a wafer sheet to protect the obverse of the wafer, on which patterns are formed. An infrared camera, which images an image formed by infrared light, and an infrared light source, which emits the infrared light to the wafer, are disposed above the wafer table. A mirror for reflecting the infrared light is disposed in the wafer table. The infrared light emitted from the infrared light source is transmitted through the wafer. Then, the infrared light is reflected on the mirror, and the reflected infrared light illuminates the pattern surface of the wafer. The infrared camera images the images of the pattern surface.

Abstract: A mechanical seal for sealing a slurry liquid between a casing and a rotary shaft comprises a fixed seat ring; a rotatable slide ring in the casing and abutting against the seat ring to form a sealing face therebetween; a helical spring in the casing and surrounding the rotary shaft, and biassing the rotatable slide ring toward the seat ring; and a rotatable ring on the rotary shaft and rotatable with the rotary shaft and holding the spring at a predetermined position relative to the rotary shaft, the spring being interposed between the rotatable slide ring and the rotatable ring. A small space is provided between the casing and the rotatable ring and the rotatable ring has a helical projection on the outer surface thereof. The helical projection of the rotatable ring and the helical spring are directed such that upon rotation thereof a force is produced in a direction away from the sealing face and toward the interior of the casing.