Abstract: A circulation type aquaculture method and a circulation type aquaculture apparatus which treat and remove ammonia harmful to fishes/shellfishes. The method includes a first step of finding an ammonia decomposition rate upon preliminarily treating cultivation water by using ozone or hypochloric acid so as to set a target remaining amount of ammonia after the decomposing treatment, a second step of finding the amount of ammonia in cultivation water so as to calculate a treating period of time required for reducing the amount of ammonia to the target remaining amount of ammonia based upon the ammonia decomposition rate of the first step, a third step of treating the cultivation water using ozone or hypochloric acid during the treating period of time calculated in the second step so as to treat and decompose ammonia in the cultivation water and a fourth step of returning the cultivation water to the aquaculture tank.

Abstract: A circulation type aquaculture method and a circulation type aquaculture apparatus which treat and remove ammonia harmful to fishes/shellfishes. The method includes a first step of finding an ammonia decomposition rate upon preliminarily treating cultivation water by using ozone or hypochloric acid so as to set a target remaining amount of ammonia after the decomposing treatment, a second step of finding the amount of ammonia in cultivation water so as to calculate a treating period of time required for reducing the amount of ammonia to the target remaining amount of ammonia based upon the ammonia decomposition rate of the first step, a third step of treating the cultivation water using ozone or hypochloric acid during the treating period of time calculated in the second step so as to treat and decompose ammonia in the cultivation water and a fourth step of returning the cultivation water to the aquaculture tank.

Abstract: A magnetic recording disk having on its surface a texture structure of fine surface irregularities with reduced variations, which is suitable for high-density magnetic recording, and a method of manufacturing such a magnetic recording disk are provided. A magnetic recording disk has a substrate 11, 12 (16) coated on a surface thereof with a magnetic layer 13, a carbon layer 14, and a lubricating film 15. The substrate has on a surface thereof a texture structure of fine surface irregularities for reducing friction when the substrate is brought into contact with a head and controlling an amount of lift of the head. The fine surface irregularities have a height of 20 nm or less and are formed from a pattern shape or profile of a shield with a high-speed atomic beam emitted from a high-speed atomic beam source.

Abstract: It is an object of the present invention to provide a method of making a magnetic disk having a uniform textured structure with micro-waviness of fabrication depth of less than 20 nm, preferably less than 10 nm, and a local depth deviation of less than 5%, in which texture patterns are characterized by the fact that lateral surfaces of the structure are sloped or curved. The object has been achieved in a method for making a magnetic disk, having micro-waviness on a fabrication surface of a substrate for reducing dynamic friction and controlling head float, by rotating and irradiating the fabrication surface with a high energy beam from a beam surface at an inclined angle to the substrate surface. The surface is irradiated through a shielding mask having a specific pattern, so as to produce a transcription pattern on the substrate surface to produce a textured structure with micro-waviness having sloped or curved side surfaces.

Abstract: A magnetic recording disk having on its surface a texture structure of fine surface irregularities with reduced variations, which is suitable for high-density magnetic recording, and a method of manufacturing such a magnetic recording disk are provided.

Abstract: A magnetic recording disk having on its surface a texture structure of fine surface irregularities with reduced variations, which is suitable for high-density magnetic recording, and a method of manufacturing such a magnetic recording disk are provided. The magnetic recording disk has a substrate 11, 12 (16) coated on a surface thereof with a magnetic layer 13, a carbon layer 14, and a lubricating film 15. The substrate has on a surface thereof a texture structure of fine surface irregularities for reducing friction when the substrate is brought into contact with a head and controlling an amount of lift of the head. The fine surface irregularities have a height of 20 nm or less and are formed from a pattern shape or profile of a shield with a high-speed atomic beam emitted from a high-speed atomic beam source.

Abstract: It is an object of the present invention to provide a method of making a magnetic disk having a uniform textured structure with micro-waviness of fabrication depth of less than 20 nm, preferably less than 10 nm, and a local depth deviation of less than 5%, in which texture patterns are characterized by the fact that lateral surfaces of the structure are sloped or curved. The object has been achieved in a method for making a magnetic disk having micro-waviness on a fabrication surface of a substrate for reducing dynamic friction and controlling head float, by rotating and irradiating the fabrication surface with a high energy beam from a beam source at an inclined angle to the substrate surface, through a shielding mask having a specific pattern, so as to process a transcription pattern on the substrate surface to produce a textured structure with micro-waviness having sloped or curved side surfaces.