Abstract: A light emitting device includes a housing; a light source unit; and a cooling unit provided in the housing to discharge heat to an outside of the housing by means of a gas, the heat being generated by the light source unit. The cooling unit includes an introduction portion, a heat exchange portion, and a circulation portion that guides the gas from the introduction portion to the heat exchange portion. The circulation portion includes a first flow path receiving the gas from the introduction portion, and a second flow path receiving the gas from the first flow path, and being connected to the heat exchange portion. The first flow path includes a portion having a flow path area larger than a flow path area of the introduction portion.

Abstract: The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a core portion and three or more arm portions, wherein each of the arm portions consists of a polymer chain comprising a structural unit represented by the following formula (1), and one end of the polymer chain is bonded to the core portion, and wherein a weight-average molecular weight Mw is 100000 or more, and a ratio of the weight-average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, is 1.6 or less. [R1 represents hydrogen or a methyl group, and R2 represents a C1 to C36 alkyl group.

Abstract: A lubricant oil composition for internal combustion engines with which further reduction of friction can be achieved to provide excellent fuel efficiency is provided. (A) A lubricant oil base oil having a kinematic viscosity at 100° C. of 2.0 to 5.0 mm2/s; (B) a molybdenum-based friction modifier in an amount of 0.005 to 0.2 mass % in terms of the mass of the molybdenum relative to the total mass of the composition; (C) a metal-based detergent in an amount of 0.01 to 1 mass % in terms of the mass of the metal relative to the total mass of the composition; and (D) 0.01 to 10 mass % of at least one compound selected from amino acids having a C6-24 alkyl, alkenyl, or acyl group, and/or derivatives of the amino acids.

Abstract: The present invention provides a lubricating oil composition for an internal combustion engine used mainly to drive a generator and to improve the fuel economy thereof. The composition comprises (A) a base oil being a hydrocarbon base oil having a ratio (CA/CB) of the proportion of the component of 24 or fewer carbon atoms (CA) and the proportion of the component of 25 or more carbon atoms (CB) in the carbon number distribution obtained by gas chromatography distillation of 2.0 or higher, the composition having a ratio (Vs/Vk) of the 80° C. high-temperature high-shear (HTHS) viscosity (Vk) and the 150° C. HTHS viscosity (Vs) of 0.35 or higher and a 100° C. kinematic viscosity of 2.5 mm2/s or higher and 5.2 mm2/s or lower.

Abstract: The present invention provides a lubricating oil composition for an internal combustion engine used mainly to drive a generator and to improve the fuel economy thereof. The composition comprises (A) a base oil being a hydrocarbon base oil having a ratio (CA/CB) of the proportion of the component of 24 or fewer carbon atoms (CA) and the proportion of the component of 25 or more carbon atoms (CB) in the carbon number distribution obtained by gas chromatography distillation of 2.0 or higher, the composition having a ratio (Vs/Vk) of the 80° C. high-temperature high-shear (HTHS) viscosity (Vk) and the 150° C. HTHS viscosity (Vs) of 0.4 or higher and a 100° C. kinematic viscosity of 5.2 mm2/s or higher and 8 mm2/s or lower.

Abstract: The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a core portion, and three or more arm portions, wherein each of the arm portions consists of a polymer chain comprising a structural unit represented by formula (1) and a structural unit represented by formula (2) and one end of the polymer chain is bonded to the core portion, and wherein a weight-average molecular weight Mw is 100000 or more, and a ratio of the weight-average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, is 1.6 or less. [R1 represents hydrogen or a methyl group, and R2 represents a group represented by formula (3), and R3 represents a C1 to C18 alkyl group that is straight-chain or has a branch having 5 or less carbon atoms: m and n are integers which satisfy m?5, n?4, and m+n?31.

Abstract: A lubricating oil composition is provided as an engine oil for an internal combustion engine employing heat management. The composition includes (A) a base oil having 100° C. kinematic viscosity of 3.0 to 5.0 mm2/s, (B) a boronated succinimide in an amount of 0.007 mass percent or more as boron and in an amount of 5 mass percent or less as the succinimide ashless dispersant, based on total mass of the composition, (C) a phenol-based antioxidant in an amount of 0.5 mass percent or more, and (D) a viscosity index improver having a ratio of weight average molecular weight and PSSI of 1.2×104 or greater in an amount of 0.1 to 5 percent by mass. The composition has a 150° C. HTHS viscosity of 2.0 to 2.8 mPa·s, a 100° C. HTHS viscosity of 4.8 mPa·s or lower and a viscosity index of 180 or greater.

Abstract: A lubricating oil composition comprising a lubricating base oil having a kinematic viscosity at 100° C. of 1 to 10 mm2/s, and a poly(meth)acrylate viscosity index improver containing a structural unit represented by the formula (1) in a proportion of 30 to 90 mol % and having a hydrocarbon main chain ratio of 0.18 or less: wherein R1 represents hydrogen or a methyl group, and R2 represents a linear or branched hydrocarbon group having a carbon number of 6 or less.

Abstract: The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a polymer chain comprising a structural unit represented by the following formula (1), wherein a weight-average molecular weight Mw is 100000 or more, and a ratio of the weight-average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, is 1.6 or less. [In the formula (1), R1 represents hydrogen or a methyl group, and R2 represents a C1 to C36 alkyl group.

Abstract: The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a core portion and three or more arm portions, wherein each of the arm portions consists of a polymer chain comprising a structural unit represented by the following formula (1), and one end of the polymer chain is bonded to the core portion, and wherein a weight-average molecular weight Mw is 100000 or more, and a ratio of the weight-average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, is 1.6 or less. [R1 represents hydrogen or a methyl group, and R2 represents a C1 to C36 alkyl group.

Abstract: An engine oil composition comprising: a lubricating base oil having a kinematic viscosity at 100° C. of 1 to 5 mm2/s; a poly(meth)acrylate viscosity index improver containing a structural unit represented by the formula (1) in a proportion of 30 to 90 mol % and having a PSSI in an ultrasonic shear test of 15 or less; and a friction modifier, the engine oil composition has a kinematic viscosity at 100° C. of 4 to 8 mm2/s, and an HTHS viscosity at 150° C. of less than 2.

Abstract: A lubricating oil composition comprising a lubricating base oil having a kinematic viscosity at 100° C. of 1 to 10 mm2/s, and a branched poly(meth)acrylate viscosity index improver containing a structural unit represented by the following formula (1) in the proportion of 30 to 90 mol % and having a branching degree of 0.1 to 8.0: wherein R1 represents hydrogen or a methyl group, and R2 represents a linear or branched hydrocarbon group having a carbon number of 6 or less.

Abstract: The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a polymer chain comprising a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), wherein Mw is 100000 or more, and Mw/Mn, is 1.6 or less. [R1 represents hydrogen or a methyl group, and R2 represents a group represented by the following formula (3), and R3 represents a C1 to C18 alkyl group that is straight-chain or has a branch having 5 or less carbon atoms. m and n are integers which satisfy m?5, n?4, and m+n?31.

Abstract: The lubricating oil composition of the invention comprises a lubricating base oil with a kinematic viscosity at 100° C. of 1-20 mm2/s, and a viscosity index improver having a ratio M1/M2 of 0.20 or greater, between the total area of the peaks between chemical shifts of 36-38 ppm M1 and the total area of the peaks between chemical shifts of 64-66 ppm M2, with respect to the total area of all of the peaks, in the spectrum obtained by 13C-NMR. The lubricating oil composition of the invention has excellent effects, with a sufficiently high HTHS viscosity at 150° C., and a sufficiently low kinematic viscosity at 40° C., a sufficiently low kinematic viscosity at 100° C. and a sufficiently low HTHS viscosity at 100° C.

Abstract: The present invention provides a lubricating oil composition for an internal combustion engine used mainly to drive a generator and to improve the fuel economy thereof. The composition comprises (A) a base oil being a hydrocarbon base oil having a ratio (CA/CB) of the proportion of the component of 24 or fewer carbon atoms (CA) and the proportion of the component of 25 or more carbon atoms (CB) in the carbon number distribution obtained by gas chromatography distillation of 2.0 or higher, the composition having a ratio (Vs/Vk) of the 80° C. high-temperature high-shear (HTHS) viscosity (Vk) and the 150° C. HTHS viscosity (Vs) of 0.35 or higher and a 100° C. kinematic viscosity of 2.5 mm2/s or higher and 5.2 mm2/s or lower.

Abstract: The present invention provides a lubricating oil composition for an internal combustion engine used mainly to drive a generator and to improve the fuel economy thereof. The composition comprises (A) a base oil being a hydrocarbon base oil having a ratio (CA/CB) of the proportion of the component of 24 or fewer carbon atoms (CA) and the proportion of the component of 25 or more carbon atoms (CB) in the carbon number distribution obtained by gas chromatography distillation of 2.0 or higher, the composition having a ratio (Vs/Vk) of the 80° C. high-temperature high-shear (HTHS) viscosity (Vk) and the 150° C. HTHS viscosity (Vs) of 0.4 or higher and a 100° C. kinematic viscosity of 5.2 mm2/s or higher and 8 mm2/s or lower.

Abstract: The lubricating oil composition of the invention comprises a lubricating base oil with a kinematic viscosity at 100° C. of 1-20 mm2/s, and a viscosity index improver having a ratio M1/M2 of 0.20 or greater, between the total area of the peaks between chemical shifts of 36-38 ppm M1 and the total area of the peaks between chemical shifts of 64-66 ppm M2, with respect to the total area of all of the peaks, in the spectrum obtained by 13C-NMR. The lubricating oil composition of the invention has excellent effects, with a sufficiently high HTHS viscosity at 150° C., and a sufficiently low kinematic viscosity at 40° C., a sufficiently low kinematic viscosity at 100° C. and a sufficiently low HTHS viscosity at 100° C.

Abstract: The present invention provides a lubricating oil composition having a low traction coefficient that can reduce the friction between parts such as gear teeth surfaces, exposed to elastohydrodynamic lubrication conditions to attain energy saving properties and high efficiency, suitable for use in manual, automatic and continuously variable transmissions of automobiles or industrial gear systems. The low traction coefficient lubricating oil composition comprises a lubricating base oil containing (A) a partial ester of a polyhydric alcohol and a carboxylic acid in an amount of 0.1 to 80 percent by mass on the basis of the total mass of the base oil and having a kinematic viscosity at 100° C. of 1 to 15 mm2/s, the composition having a kinematic viscosity at 100° C. of 1 to 20 mm2/s.