Abstract: In a rolling mill (101) with upper and lower drive motors (174 and 184) arranged oppositely to each other with respect to paired upper and lower work rolls (131 and 141), changing of the upper work roll (131) is carried out such that a changing carriage (400) is inserted from a lower drive motor side to a space in the rolling mill (101) provided by the lower work roll (141) extracted from the rolling mill (101) to an upper drive motor side, the upper work roll (131) being loaded on the changing carriage (400) and then extracted together therewith to the lower drive motor side.

Abstract: A circular fluorescent lamp has a fluorescent tube of a generally circular shape having electrodes fixed gastight in both of its ends respectively to enclose inert gas and mercury therein. A cap is mounted to bridge between the tube ends. The fluorescent tube has an oval section taken along a line perpendicular with respect to its axis. The rate of ovalness y/x, representing the ratio between the larger tube diameter y and the smaller tube diameter x of the tube sectional shape, preferably lies within the range of 1.10 to 1.30.

Abstract: A phosphor system consisting of an alkaline-earth metal silicate host lattice activated by trivalent terbium together with monovalent alkaline metal as a charge compensator, said phosphor system corresponding to the formula, X.sub.3-x Y.sub.1-x Si.sub.2 O.sub.8 : Tb.sub.x, Z.sub.x wherein X is at least one of Ba, Sr, and Ca; Y is at least one of Mg and Zn; and Z acting as a charge compensator is at least one of Li, K, and Na, and x is from 0.001 to 0.95, said phosphor system substituting Ca plus Mg for X plus Y of the formula being excluded. The present invention provides an efficient green-emitting phosphor particularly useful for a deluxe fluorescent lamp.