Abstract: An apparatus for removing acid constituents such as HCl and/or SO.sub.x from the waste-gas generated by furnaces,incinerators and the like wherein the calcium-containing powder material is blown into a waste-gas duct to form a lean fluidized flow until it reaches a vertical moving bed filter having two louvered walls between which granular packings are filled. The process for removing the acid constituents is accomplished by chemisorption which occurs first in the duct and then in the filter bed. A recycled use of the powder is preferred. The filtered waste-gas is further purified by an electrostatic precipitator. The use of a moving bed filter permits the use of a greater amount of calciumaceous powder relative to the acid gases without increasing the electrical load on the electrostatic precipitator.

Abstract: This invention relates to means for locating an ultra-precision positioning of a table, in which a rough moving of the table is made by a motor connected to the aforesaid means, while a minute moving thereof is done by a piezo-electric element mounted on a ball screw shaft to be driven by the motor, whereby an ultra-precision positioning of the table can be carried out smoothly. Accordingly, it is unnecessary to dispose a roughly moving table and a minutely moving table separately within a device.

Abstract: This invention relates to means for locating an ultra-precision positioning of a table, in which a rough moving of the table is made by a motor connected to the aforesaid means, while a minute moving thereof is done by a piezoelectric element mounted on a ball screw shaft to be driven by the motor, whereby an ultra-precision positioning of the table can be carried out smoothly. Accordingly, it is unnecessary to dispose a roughly moving table and a minutely moving table separately within a device.