Abstract: Novel porphyrin derivatives of the general formula: ##STR1## wherein R.sub.1 each independently denotes a hydrogen, a C.sub.1 -C.sub.4 alkyl group or an ethenyl group, and R.sub.2 each independently denotes COZ(C.sub.m H.sub.2m)Q, COZCH(C.sub.m H.sub.2m Q).sub.2, --CH.sub.2 --Q [wherein Z is O, S or NH, m is an integer of 1 to 23, and Q is a di-(C.sub.1 -C.sub.4 alkyl)amino group or tri-(C.sub.1 -C.sub.4 alkyl)ammonium halide group] or ##STR2## (wherein X is a halogen); or R.sub.1 each independently denotes --C.sub.2 H.sub.4 --Q (wherein Q is the same as defined above), ##STR3## (wherein X is the same as defined above), and R.sub.2 each independently denotes a carboxyl group or a C.sub.1 -C.sub.4 alkoxycarbonyl group, and the production thereof are described. The quarternary ammonium salt type of the above compounds exhibit affinity and photosensitizing activity for cancer cells and can be employed for diagnosing and treating cancer under irradiation of laser light.

Abstract: A mounting structure for chemical injection tube for a geothermal well which is used to generate power from geothermal energy is provided. A chemical injection tube is wound spirally along the outer surface of a vertical pipe. A double structure of a casing pipe of the geothermal well including the injection tube, which is inserted between the pipes, extends deep in the well below, the flashing point of the well. A plug is inserted at the lower end of the tube. The plug is removed by compressed air or water prior to the injection of scale inhibiting chemicals from the top of the tube. Thus, the chemical injection tube protects the well from the deposition of carbonate scale thereby providing a stable power plant operation.

Abstract: An internal combustion engine having a helically-shaped intake port. When the intake manifold vacuum is in the range of about -500 through -250 mmHg, a super lean mixture is fed into the cylinders of the engine. When the intake manifold vacuum is in the range of about -250 through -100 mmHg, a fuel mixture, having the stoichiometric air-fuel ratio, is fed into the cylinders of the engine. When the intake manifold vacuum is smaller than about -100 mmHg, a rich mixture is fed into the cylinders of the engine.