Abstract: A method for converting benzene and aromatic hydrocarbon compounds having 9 or more carbon atoms contained in a material oil having a boiling point of 30˜210° C. into toluene and aromatic hydrocarbon compounds having 8 carbon atoms in the presence of hydrogen and the said catalyst. The catalyst can be obtained by carrying at least one metal or metal compound selected from Group VIII and Group VIA of the Periodic Table on a carrier containing zeolites in which maximum diameter among diameters of its micropores is 0.6-1.0 nm and a ratio of SiO2/Al2O3 is 50 or more.

Abstract: There is provided a catalyst exhibiting a high activity and less catalytic deterioration, as well as a high selectivity, suitable for use in allowing aromatic hydrocarbons of 9 or more carbon atoms to react, and thereby converting them into toluene and aromatic hydrocarbons of 8 carbon atoms more useful as gasoline bases, and a conversion method using the catalyst. The catalyst is used for converting aromatic hydrocarbons of 9 or more carbon atoms in a material oil containing a component with a boiling point exceeding 210° C. into toluene and aromatic hydrocarbons of 8 carbon atoms in the presence of hydrogen, and contains a carrier containing one or more than one zeolites in which the maximum pore diameter of micropores is in a range of 0.6 to 1.0 nm; and one or more than one metals selected from the Group VIA metals of the Periodic Table or compounds thereof.

Abstract: A gear finishing apparatus includes a bed having a horizontally extending guide member and a vertically extending guide member, a grinding wheel support unit movable along the horizontally extending guide member and having a grinding wheel unit, a ring-shaped grinding wheel in the form of an internal gear rotatably supported on the grinding wheel head for rotation about a substantially vertical axis, a first actuator for moving the grinding wheel support unit along the horizontally extending guide member, a workpiece support unit movable along the vertically extending guide member, the workpiece support unit having a holding device for holding a gear blank having external gear teeth for rotation about a substantially vertical axis, a second actuator for moving the workpiece support unit along the vertically extending guide member to move the gear blank into and out of the grinding wheel, and a third actuator for rotating the grinding wheel to hone the gear teeth of the gear blank while the gear blank is being

Abstract: A rack and pinion gearing comprising a helical rack and a spiral pinion. The rack has a structure defined by a radius, a distance from the axis to tooth crest, a helix angle, and a pressure angle determined from the viewpoint of applied kinematics so as to produce a balancing moment of rotation. The structure keeps the rack free from inclination and rocking about the axis which would otherwise result in a biting effect.