Abstract: A propeller shaft (1) that is a power transmission shaft has a shaft member (2) as a tubular body made of iron-based metal and a balance weight (3) made of iron-based metal and welded to an outer peripheral surface of this shaft member (2). At least a part of the balance weight (3) of the propeller shaft (1) is covered with a sacrificial metal coating (4) made of sacrificial corrosion prevention material that contains metal whose ionization tendency is higher than that of metal forming the shaft member (2). With this, it is possible to suppress local progression of corrosion at a periphery of the balance weight (3) and improve durability of the propeller shaft (1).

Abstract: A micro-bar code data processing system is capable of reducing the number of digits to be expressed by the micro-bar code by compressing information to be contained therein. The micro-bar code data processing system includes a receiver for receiving an original data to be contained in a micro-bar code; a reducer for reducing the number of digits of the original data by compressing the received original data; a converter for converting the compressed data into an encoded micro-bar code data; an outputter for outputting the encoded micro-bar code data; a receiver for receiving encoded data contained in the micro-bar code; a converter for converting the received encoded data into a compressed data; a restorer for restoring the original data from the compressed data by decompression of the compressed data, and an outputter for outputting the restored original data.

Abstract: A bar code reader system is adapted to read a micro-bar code and includes a light emitting body for irradiating a light beam onto a bar code surface on which the micro-bar code to be read is provided. A focusing lens focuses a reflected light from the bar code surface. An image pick-up device receives the focused reflected light and forms an image of the micro-bar code to be read. A cylindrical lens body is arranged to pass therethrough both the light beam from the light emitting body and the reflected light beam reflected from the bar code surface. The cylindrical lens body is oriented with an axis thereof substantially consistent with a bar code reading direction.