Abstract: A method of producing a lithium-ion secondary battery includes the following (?) and (?): (?) preparing a lithium-ion secondary battery, the lithium-ion secondary battery including at least a positive electrode, a negative electrode, and an electrolyte solution; and (?) adding a zwitterionic compound to the electrolyte solution. The negative electrode includes at least a negative electrode active material and a film. The film is formed on a surface of the negative electrode active material. The film contains a lithium compound. The zwitterionic compound contains a phosphonium cation or an ammonium cation and a carboxylate anion in one molecule.

Abstract: A suction apparatus of a multi-cylinder internal combustion engine has a suction manifold disposed in a direction parallel with a row of cylinders at one side of a cylinder head. The suction apparatus includes a plurality of independent suction passages of equal length each extending from an engine main body at right angle, a suction gathering chamber connected to the suction passages and disposed in the direction parallel with the row of cylinders, a throttle body provided at an upper stream end of the suction gathering chamber, and a resonance vessel communicating with the suction gathering chamber. The resonance vessel is supported by a cylinder head cover and a wall of the gathering chamber elastically through rubber members covering above of the independent suction passages with a space, and communicates with an upper part of the suction gathering chamber at a just downstream position of the throttle body.

Abstract: An optical system includes a first optical element formed of a noncrystalline polyester resin having a copolymer ratio of 9,9-bis [4(2-hydroxyethoxy) phenyl]fluorene in a range of 35 molar percent to 45 molar percent when the dicarboxylic acid component is 100 molar percent, and a second optical element formed of material incorporating an ultraviolet light absorption agent and disposed at least either anteriorly or posteriorly to the first optical element.

Abstract: A zoom finder optical system of real image type of the present invention is provided with an objective lens system of a positive refractive power, a condenser lens of a positive refractive power and an eyepiece system of a positive refractive power from an object side. The objective lens system includes from the object side a first lens unit of negative refractive power, a second lens unit of a negative refractive power, a third lens unit of a positive refractive power and a fourth lens unit of a positive refractive power.

Abstract: An eyepiece for use in a viewfinder optical system has a wide dioptric power adjustment range. The eyepiece is provided with, from a side of a secondary-image plane formed by a first, a second, and a third relay lens, a first, a second, and a third eyepiece lens having a positive, a negative, and a positive refractive power, respectively. For dioptric power adjustment, the positive first eyepiece lens or the negative second eyepiece lens is moved in an optical axis direction.