Abstract: In a lighting apparatus which illuminates light ray from an illumination light source through a light distribution lens onto an illuminated surface, an inner surface of the light distribution lens is formed as continuous surface to receive incident ray in the perpendicular direction, and an outer surface of the lens for refracting outgoing ray is formed based on the equations which are made in consideration of the illuminance on the illuminated surface, thereby uniform illuminance is obtained on the illuminated surface.

Abstract: In a process for directly liquefying coal, a paste consisting of finely divided coal, catalyst and heavy oil can be treated for thermal cracking and hydrocracking with a high liquid/space ratio and short residence time in a preheating section and a reaction section. An apparatus threfor comprises a plural number of pipe units having apertures for hydrogen injection and apertures for the paste of a low concentration or heavy oil injection and a gas-liquid separator for removing H.sub.2 O, methane, etc., the pipe units being formed in such a manner that a Reynolds number of 3.times.10.sup.3 or greater and an axial dispersion coefficient of 0.05 or smaller are achieved for the fluid flow therein.