Abstract: This invention relates to lubricant base oil having high viscosity indexes and low pour points, and particularly to lubricant base oil consisting essentially of a normal paraffin and an isoparaffin, wherein (a) an average carbon number Nc in one molecule is not less than 28 but not more than 40, and (b) an average branch number Nb in one molecule calculated from a ratio of CH3 carbon to total carbon determined by 13C-NMR analysis and the average carbon number Nc in one molecule is not more than (0.2Nc?3.1) but not less than 1.5.

Abstract: Provided are a method for producing a super-low sulfur gas oil blending component or a super-low sulfur gas oil composition having a sulfur content of less than 5 mass ppm, under relatively mild conditions, without greatly increasing the hydrogen consumption and without remarkably decreasing the aromatic content; and a super-low sulfur gas oil composition having a sulfur content of less than 5 mass ppm which exhibits a high heating value, is excellent in fuel economy and output power, and is free from an adverse effect on a sealing rubber member or the like used in the fuel injection system and thus does not cause the leakage of a fuel. A method for producing a super-low sulfur gas oil blending component or a super-low sulfur gas oil composition having a sulfur content of less than 5 mass ppm is also disclosed.

Abstract: Provided are a method for producing a super-low sulfur gas oil blending component or a super-low sulfur gas oil composition having a sulfur content of less than 5 mass ppm, under relatively mild conditions, without greatly increasing the hydrogen consumption and without remarkably decreasing the aromatic content; and a super-low sulfur gas oil composition having a sulfur content of less than 5 mass ppm which exhibits a high heating value, is excellent in fuel economy and output power, and is free from an adverse effect on a sealing rubber member or the like used in the fuel injection system and thus does not cause the leakage of a fuel. A method for producing a super-low sulfur gas oil blending component or a super-low sulfur gas oil composition having a sulfur content of less than 5 mass ppm is also disclosed.

Abstract: This invention relates to lubricant base oil having high viscosity indexes and low pour points, and particularly to lubricant base oil consisting essentially of a normal paraffin and an isoparaffin, wherein (a) an average carbon number Nc in one molecule is not less than 28 but not more than 40, and (b) an average branch number Nb in one molecule calculated from a ratio of CH3 carbon to total carbon determined by 13C-NMR analysis and the average carbon number Nc in one molecule is not more than (0.2Nc?3.1) but not less than 1.5.

Abstract: Method of producing lead-free gasoline composition having a sulfur content of 1 ppm or less and an octane number of 89.0 or more, includes: subjecting a cracked naphtha fraction exhibiting a temperature for 5 vol % distillation of 25° C. or higher and for 95 vol % distillation of 210° C. or lower, an olefin content of 5 mass % or more and a diene number of 0.3 g/100 g or less to a desulfurization treatment, and mixing the resultant desulfurized cracked naphtha fraction with another gasoline base material; and a lead-free gasoline composition having an octane number of 89.0 or more, a temperature for 50 vol % distillation of 105° C. or lower, has an olefin content of 10 vol % or more and a total sulfur content of 1 ppm or less, and a percentage of a thiophene type sulfur compound in the total sulfur content of 50% or more.

Abstract: The two-stage hydrocracking process of the present invention comprises bringing the first-stage feed oil containing a hydrocarbon component and having a boiling point of 316° C. or higher into contact with the first-stage catalyst in the presence of hydrogen to obtain a first-stage product; separating the first-stage product into heavy component and light component containing the middle distillate products; bringing the second-stage feed oil containing heavy component of the first-stage reaction product into contact with the second-stage catalyst in the presence of hydrogen to obtain the second-stage product; separating the second-stage product into heavy component and light component comprising middle distillate products and recycling part of the heavy component of the second-stage product to the second-stage feed oil. Hydrocracking activity of the first-stage catalyst is higher than hydrocracking activity of the second-stage catalyst.

Abstract: A hydrocracking catalyst has a carrier that has particles of a compound oxide and a binder present between these particles, and at least one metal component selected from Group 6, Group 9 or Group 10 of the Periodic Table supported on the carrier. The catalyst has a median pore diameter of 40 to 100 Å and the volume of pores whose pore diameter falls within a range of 40 to 100 Å is at least 0.1 mL/g. Moreover, the volume of pores of the catalyst whose pore diameter falls within a range of 0.05 to 5 &mgr;m is 0.05 to 0.5 mL/g, and the volume of pores whose pore diameter is 0.5 to 10 &mgr;m is less than 0.05 mL/g. This catalyst is mechanically strong enough for practical use and has a high conversion rate and middle distillate selectivity in hydrocracking of hydrocarbon oils, particularly vacuum gas oil.

Abstract: Hydrorefining catalyst contains 0.1 to 25 wt % in total of at least one hydrogenation active metal element selected from elements of Group 6, Group 8, Group 9, and Group 10 of the Periodic Table, and 0.1 to 3 wt % potassium on a carrier formed of porous inorganic oxide. The concentration distribution of the hydrogenation active metal element is higher in the central part than in the peripheral part of the catalyst, and the concentration distribution of potassium is higher in the peripheral part than in the central part of the catalyst. The pores on the outside surface of the catalyst are not plugged by the metal content of hetero compounds and hetero compounds can be efficiently diffused to inside the catalyst. As a result, long-term retention of a state of high activity is possible.

Abstract: The two-stage hydrocracking process of the present invention comprises bringing the first-stage feed oil containing a hydrocarbon component and having a boiling point of 316° C. or higher into contact with the first-stage catalyst in the presence of hydrogen to obtain a first-stage product; separating the first-stage product into heavy component and light component containing the middle distillate products; bringing the second-stage feed oil containing heavy component of the first-stage reaction product into contact with the second-stage catalyst in the presence of hydrogen to obtain the second-stage product; separating the second-stage product into heavy component and light component comprising middle distillate products and recycling part of the heavy component of the second-stage product to the second-stage feed oil. Hydrocracking activity of the first-stage catalyst is higher than hydrocracking activity of the second-stage catalyst.

Abstract: In a disk device including, on a base, at least one recording disk rotated by a spindle motor, a carriage equipped with heads for executing read/write operations with the recording disk and a voice coil motor for driving the carriage, whereby the carriage includes an arm portion for mounting the heads at a distal end thereof, a main body equipped with a rotary shaft and a rotor portion serving as a rotor of the voice coil motor, the present invention provides a carriage structure capable of reducing noise and accomplishing a high transfer rate. According to the first embodiment, an anchor member comprising a flat sheet portion and an extension portion and made of a sheet metal is disposed on the flat surface portion of the side surface of the carriage main body, and a flexible circuit board is wound on the anchor member and is, in this state, connected to the carriage. Therefore, a package area on the carriage side can be increased.

Abstract: A disk drive includes a disk drive housing and a frame that supports the disk drive housing, wherein a thermally conductive elastic member is interposed between the disk drive housing and the frame for conducting heat in the disk drive housing to the frame and for isolating vibration.

Abstract: A breather structure for ventilation between the inside and outside of the housing of the disk drive is realized by a simple, inexpensive construction. The cover structure is for a disk drive provided on a base with a spindle motor carrying recording disks and an actuator for driving a carriage carrying heads for writing information on the disks, with the inside sealed airtight by attaching a cover to the gas through a gasket, and with an antivibration plate for preventing vibration and noise from generating when driving the disks at the surface of the cover contacting the outside air either directly or through a viscoelastic member.

Abstract: A magnetic disk drive having one or more magnetic disks, one or more read/write heads each recording or reproducing information for a corresponding one of the magnetic disks, a servo head reading control information from a predetermined one of the magnetic disks, and an actuator supporting the one or more read/write heads and the servo head includes first leads extending from the one or more read/write heads along one side of the actuator, and second leads extending from the servo head along the other side of the actuator so that the second leads can be distanced in space from the first leads.

Abstract: A breather filter unit for a magnetic disk drive including a base and a cover fixed to the base, the cover having a vent. The breather filter unit includes a casing fixed to an inner surface of the cover, the casing having a vent inlet communicating with the vent of the cover and a vent outlet communicating with an inside of the magnetic disk drive, and a first filter contained in the casing at a position adjacent to the vent inlet, the first filter being formed from a plurality of fibers extending in a direction substantially parallel to that of an air flow from the vent inlet to the vent outlet. The breather filter unit further includes a second filter bonded to the casing so as to cover the vent outlet, and an activated carbon layer contained in the casing at a position between the first filter and the second filter.

Abstract: Disclosed is a magnetic disk apparatus having a large internal accommodation space. This magnetic disk apparatus comprises a case defining accommodation space inside, magnetic disks disposed in the accommodation space, a spindle motor, magnetic heads and a rotary actuator. The case includes a cover having a first flat portion and a first upright portion standing upright on the first flat portion at a peripheral portion thereof, and a base having a second flat portion and a second upright portion standing upright on the second flat portion at a peripheral portion thereof. This design can ensure a sufficient strength even if the case is made thin, thus allowing the internal accommodation space to be increased. The magnetic disk apparatus also has a printed circuit board, which is provided at the case and has a control circuit mounted thereon for controlling the magnetic heads. The printed circuit board supplies a source voltage to the case.

Abstract: A head actuator for a magnetic disk drive unit which eliminates the possibility of track slip due to a mechanical external force and allows high-speed access. The head actuator includes a carriage having a body provided rotatably to a shaft fixed to a housing and an arm fixed to the body so as to extend substantially perpendicularly to the shaft, a supporting member mounted on the body on its side opposite to the arm with respect to the shaft, and a coil fixed to the supporting member and receiving a driving force from a static magnetic field. The supporting member is formed of a material having a specific gravity larger than that of a material forming the body of the carriage.

Abstract: A breather filter unit for a magnetic disk drive including a base and a cover fixed to the base, the cover having a vent. The breather filter unit includes a casing fixed to an inner surface of the cover, the casing having a vent inlet communicating with the vent of the cover and a vent outlet communicating with an inside of the magnetic disk drive, and a first filter contained in the casing at a position adjacent to the vent inlet, the first filter being formed from a plurality of fibers extending in a direction substantially parallel to that of an air flow from the vent inlet to the vent outlet. The breather filter unit further includes a second filter bonded to the casing so as to cover the vent outlet, and an activated carbon layer contained in the casing at a position between the first filter and the second filter.

Abstract: A magnetic disk drive having one or more magnetic disks, one or more read/write heads each recording or reproducing information for a corresponding one of the magnetic disks, a servo head reading control information from a predetermined one of the magnetic disks, and an actuator supporting the one or more read/write heads and the servo head includes first leads extending from the one or more read/write heads along one side of the actuator, and second leads extending from the servo head along the other side of the actuator so that the second leads can be distanced in space from the first leads.

Abstract: A magnetic disk device includes a flexible printed circuit board having a first portion provided with read/write ICs for read/write heads and first printed patterns connected to the read/write ICs and a second portion positioned within the first portion, an end of the second portion being connected to the first portion so as to be bendably projected from the first portion, the second portion being provided with a servo IC for the servo head and second printed patterns connected to the servo IC, the flexible printed circuit board being mounted on an actuator body such that one end of the first portion lies outside the actuator and the second portion lies on the actuator body. The magnetic disk device also includes first lead wires of the read/write heads extending to the flexible printed circuit board and being connected to the first patterns, and second lead wires of the servo head extending to the flexible printed circuit board and being connected to the second printed patterns.

Abstract: A swing head arm type magnetic disc apparatus includes a magnetic disc having a data R/W zone and a CSS zone, and is accommodated in a housing and a spindle rotably supported on the housing, a head arm provided with a floating-type magnetic head and secured to the spindle, a motor for driving the spindle when a seek operation is performed, and apparatus for imparting torque to the spindle. The torque imparting apparatus imparts torque such that the total torque obtained by summing up torque provided by a head arm and the torque by the torque imparting apparatus itself is made uniform irrespective of rotational position of a head arm, and acts in a direction which causes the magnetic head to move toward the CSS zone.