Abstract: A manufacturing method of a semiconductor device disclosed herein, comprises: forming a buried insulating film in a semiconductor substrate; forming semiconductor elements isolated by the buried insulating film; cleaning a surface side of the semiconductor substrate with a cleaning solution; and covering a surface side of the buried insulating film with a protective film before the step of cleaning the surface side of the semiconductor substrate, wherein a protective film is resistant to the cleaning solution.

Abstract: An oil separator comprises an oil chamber having a first space on an upper side and a second space on a lower side which communicate with each other. An air-fuel mixture transport pipe is connected to a peripheral portion of the oil chamber so as to communicate with the second space. An oil discharge pipe is connected to a lower end portion of the oil chamber. A blow-by gas discharge pipe is connected to an upper end portion of the oil chamber. The second space communicates with the first space so as to inhibit the oil from flowing from the second space into the first space. The first space communicates with the blow-by gas discharge pipe so as to inhibit the oil from flowing from the first space into the blow-by gas discharge pipe. The flow direction at one end portion of the air-fuel mixture transport pipe substantially corresponds with the circumferential direction of the oil chamber.

Abstract: Disclosed is a jet-propulsion watercraft having a simple structure for drawing water as cooling water, the inside of which may be cleaned easily. The watercraft typically comprises an engine, a water jet pump driven by the engine, a two-part pump casing, at least one water drawing passage provided so as to communicate with an inside of the water jet pump in a portion where the two parts of the pump casing are connected to each other, and a component cooled by cooling water taken through the water drawing passage.

Abstract: A first exhaust chamber and a second exhaust chamber are disposed within a body of a watercraft. The first exhaust chamber communicates with an exhaust port of an engine through a first exhaust pipe. A first space of the first exhaust chamber communicates with the second exhaust chamber through a first inverted-U shaped pipe. The second exhaust chamber communicates with another space of the first exhaust chamber through a second inverted-U shaped pipe. The first and second inverted-U shaped pipes are each positioned in the flow path of the exhaust gas and bent to be substantially inverted-U shaped. The other space of the first exhaust chamber communicates with an outside of the body through a second exhaust pipe. An uppermost portion of the first inverted-U shaped pipe and an uppermost portion of the second inverted-U shaped pipe are located higher than a waterline of the watercraft.

Abstract: An engine for a personal watercraft uses an open-looped cooling system and comprises a cylinder block having a water jacket within which cooling water flows, and a piston that reciprocates within the cylinder block, and a dimension of the water jacket in a reciprocation direction of the piston is equal to or less than a half of a reciprocation distance of the piston.

Abstract: An oil cooler of an engine for small watercraft. The oil cooler typically includes a mounting portion configured to mount the oil cooler on an outer wall face of an engine of the small watercraft, an oil passage configured to allow oil to flow therethrough and lead to outside of the oil cooler at the mounting portion, and a coolant passage through which coolant for cooling the oil flows, wherein the oil cooler is capable of being disassembled such that an inside of at least the coolant passage is exposed.

Abstract: A small watercraft comprises an engine for propelling a body of the watercraft, an oil tank configured to reserve oil for lubricating the engine, an oil separator configured to separate the oil from a blow-by gas of the engine, and an oil return passage configured to return the separated oil to the oil tank, wherein a baffle member is provided in the vicinity of an opening portion at which the oil return passage opens in the oil tank so as to inhibit the oil from moving from a predetermined direction toward the opening portion of the oil return passage within the oil tank.

Abstract: A first exhaust chamber and a second exhaust chamber are disposed within a body of a watercraft. The first exhaust chamber communicates with an exhaust port of an engine through a first exhaust pipe. A first space of the first exhaust chamber communicates with the second exhaust chamber through a first inverted-U shaped pipe. The second exhaust chamber communicates with another space of the first exhaust chamber through a second inverted-U shaped pipe. The first and second inverted-U shaped pipes are each positioned in the flow path of the exhaust gas and bent to be substantially inverted-U shaped. The other space of the first exhaust chamber communicates with an outside of the body through a second exhaust pipe. An uppermost portion of the first inverted-U shaped pipe and an uppermost portion of the second inverted-U shaped pipe are located higher than a waterline of the watercraft.

Abstract: An oil separator comprises an oil chamber having a first space on an upper side and a second space on a lower side which communicate with each other. An air-fuel mixture transport pipe is connected to a peripheral portion of the oil chamber so as to communicate with the second space. An oil discharge pipe is connected to a lower end portion of the oil chamber. A blow-by gas discharge pipe is connected to an upper end portion of the oil chamber. The second space communicates with the first space so as to inhibit the oil from flowing from the second space into the first space. The first space communicates with the blow-by gas discharge pipe so as to inhibit the oil from flowing from the first space into the blow-by gas discharge pipe. The flow direction at one end portion of the air-fuel mixture transport pipe substantially corresponds with the circumferential direction of the oil chamber.

Abstract: A manufacturing method of a semiconductor device disclosed herein, comprises: forming a buried insulating film in a semiconductor substrate; forming semiconductor elements isolated by the buried insulating film; cleaning a surface side of the semiconductor substrate with a cleaning solution; and covering a surface side of the buried insulating film with a protective film before the step of cleaning the surface side of the semiconductor substrate, wherein a protective film is resistant to the cleaning solution.

Abstract: A small watercraft including an engine mounted in a body such that an axial direction of a crankshaft corresponds with a longitudinal direction of the body, an oil tank provided such that a longitudinal direction thereof corresponds with the axial direction of the crankshaft, a first communicating port and a second communicating port formed in the oil tank at least two positions spaced apart from each other in the longitudinal direction, a gas-release chamber having a third communicating port and a fourth communicating port provided at two positions spaced apart from each other, and at least one fifth communicating port located to communicate with an ambient side, the gas-release chamber having a bottom face located higher than a liquid level of oil inside the oil tank, wherein the first communicating port communicates with the third communicating port and the second communicating port communicates with the fourth communicating port.

Abstract: Disclosed is a personal watercraft capable of separating and eliminating water contained in fuel without inspecting whether or not the water is present in a fuel tank. The personal watercraft comprises a water separator 21 in a fuel supply passage from a fuel tank 14 for reserving fuel supplied to an internal combustion engine 4 to an air-fuel mixture generating means 17 for mixing fuel with air to generate air-fuel mixture.

Abstract: Disclosed is a personal watercraft having a water cooling system of an engine, which allows inside of a cooling water passage of an engine or a water passage connected to the cooling water passage to be sufficiently cleaned and a clogged water-supply hole in an expansion chamber to be easily inspected or cleaned. The personal watercraft 1 comprises a first water passage 50 from a water jet pump 7 to a cooling water passage of an engine 4. Water is forcibly sent by the water jet pump 7 and led to the cooling water passage through the first water passage 50. The water flows through the cooling water passage while exchanging heat, and the resulting water is discharged outside the watercraft. The personal watercraft 1 further comprises a second water passage 53 opened in a surface of a body of the watercraft and communicating with the first water passage 50, and an opening/closing means 54 for opening/closing the second water passage 53.

Abstract: Disclosed is a jet-propulsion watercraft capable of maintaining cooling capability in an exhaust passage even when one cooling water passage is clogged with substances. The jet-propulsion watercraft comprises: an engine having a cooling water passage; an exhaust passage having a double-walled structure comprised of inner and outer walls between which a cooling water passage is at least partially formed; a water jet pump, the water jet pump pressurizing and accelerating water and ejecting the water from the outlet port, and supplying part of the water to the cooling water passages of the engine and the exhaust passage; a water-supply hole formed in the inner wall of the double-walled structure; a first cooling water passage for supplying the cooling water to the cooling water passage between the outer wall and the inner wall; and a bypass passage formed independently of the first cooling water passage.

Abstract: Disclosed is a jet-propulsion watercraft having a simple structure for drawing water as cooling water, the inside of which may be cleaned easily. The watercraft typically comprises an engine, a water jet pump driven by the engine, a two-part pump casing, at least one water drawing passage provided so as to communicate with an inside of the water jet pump in a portion where the two parts of the pump casing are connected to each other, and a component cooled by cooling water taken through the water drawing passage.

Abstract: Disclosed is a personal watercraft having a water cooling system of an engine, which allows inside of a cooling water passage of an engine or a water passage connected to the cooling water passage to be sufficiently cleaned and a clogged water-supply hole in an expansion chamber to be easily inspected or cleaned. The personal watercraft 1 comprises a first water passage 50 from a water jet pump 7 to a cooling water passage of an engine 4. Water is forcibly sent by the water jet pump 7 and led to the cooling water passage through the first water passage 50. The water flows through the cooling water passage while exchanging heat, and the resulting water is discharged outside the watercraft. The personal watercraft 1 further comprises a second water passage 53 opened in a surface of a body of the watercraft and communicating with the first water passage 50, and an opening/closing means 54 for opening/closing the second water passage 53.

Abstract: A polyester aqueous dispersion having excellent properties in waterproof, weatherproof, processibility and adhesion, which provides a large allowance for controlling liquid physical properties by post treatment and is advantageous in making dry powders from the dispersion, and an efficient method for preparing the aqueous dispersion at low costs in a simple manner. The polyester aqueous dispersion comprising (i) a water-insoluble polyester and (ii) a polyester containing a sulfonate group bound to a polymer in a concentration of 0.1 to 1.5 mmol equivalents when calculated as —SO3− group per gram of the polymer, and method for preparing a polyester aqueous dispersion comprises a step of melt-kneading a resin composition comprising the water-insoluble polyester (i) and polyester (ii) and a step of phase inversion of adding water or a basic aqueous solution to the molten kneaded mixture thereby to shift the resin composition into the aqueous dispersion.

Abstract: Disclosed is a personal watercraft capable of separating and eliminating water contained in fuel without inspecting whether or not the water is present in a fuel tank. The personal watercraft comprises a water separator 21 in a fuel supply passage from a fuel tank 14 for reserving fuel supplied to an internal combustion engine 4 to an air-fuel mixture generating means 17 for mixing fuel with air to generate air-fuel mixture.

Abstract: Disclosed is a jet-propulsion watercraft capable of maintaining cooling capability in an exhaust passage even when one cooling water passage is clogged with substances. The jet-propulsion watercraft comprises: an engine having a cooling water passage; an exhaust passage having a double-walled structure comprised of inner and outer walls between which a cooling water passage is at least partially formed; a water jet pump, the water jet pump pressurizing and accelerating water and ejecting the water from the outlet port, and supplying part of the water to the cooling water passages of the engine and the exhaust passage; a water-supply hole formed in the inner wall of the double-walled structure; a first cooling water passage for supplying the cooling water to the cooling water passage between the outer wall and the inner wall; and a bypass passage formed independently of the first cooling water passage.

Abstract: Disclosed is a personal watercraft capable of appropriately detecting temperatures of an engine and an exhaust manifold by using one temperature sensor and in particular capable of finding that cooling water flow is stagnant in cooling systems of them based on the detection of the temperatures. The personal watercraft comprises a water-cooled multi-cylinder engine placed in an engine room of a body, an exhaust manifold for gathering an exhaust gas from the engine, the exhaust manifold being cooled by cooling water, and a temperature sensor provided so as to be located downstream of the vicinity of an end of the exhaust manifold that is located downstream in an exhaust gas flow path.