Abstract: An electrolyte solution containing at least one compound (1) selected from the group consisting of a compound represented by the following formula (1-1) (wherein R111 to R113 are each individually a C1-C4 linear or branched alkyl group, and at least one selected from R111 to R113 is a C1-C4 branched alkyl group) and a compound represented by the following formula (1-2) (wherein R121 to R123 are each individually a C1-C4 linear or branched alkyl group, and at least one selected from R121 to R123 is a C1-C4 branched alkyl group).

Abstract: An electrolyte solution containing LiFSO3 and a compound (1) represented by the following formula (1): LiZ, wherein Z is PF6, BF4, N(FSO2)2, N(CF3SO2)2, N(C2F5SO2)2, PO2F2, or B(C2O4)2. The electrolyte solution has a ratio [FSO3]/[Z] of a molar content of FSO3 [FSO3] to a molar content of Z [Z] of 3 to 1000. Also disclosed is an electrochemical device including the electrolyte solution, a lithium ion secondary battery including the electrolyte solution and a module including the electrochemical device.

Abstract: An electrolyte solution containing a compound represented by formula (1) and a compound represented, for example, by formula (11-1), the formula (1) being: wherein M101 is P or P?O; R101 is a group such as a C1-C11 alkylsilyloxy group; n101 is an oxidation number of M101 minus 1 or an oxidation number of M101 minus 3; and R102 to R104 are each individually a group such as a C1-C11 alkyl group; the formula (11-1) being: wherein R111 and R112 are the same as or different from each other and are each an atom or group such as a hydrogen atom; and R113 is a group such as an alkyl group free from a fluorine atom.

Abstract: An electrolyte solution capable of reducing the initial resistance of an electrochemical device, and an electrochemical device including the electrolyte solution. The electrolyte solution contains a compound represented by formula (I-1): wherein R111 to R113 are each individually a C1-C4 linear alkyl group, and wherein the compound (1-1) is present in an amount of 0.01-1000 mass ppm relative to the electrolyte solution.

Abstract: An electrolyte solution containing a compound (1) represented by the formula (1), (wherein R101 and R102 are each individually a substituent such as a C1-C7 alkyl group, and the substituent optionally contains at least one divalent to hexavalent hetero atom in a structure or optionally has a structure obtained by replacing at least one hydrogen atom by a fluorine atom or a C0-C7 functional group) and at least one compound (11) selected from compounds such as a compound represented by formula (11-1) (wherein R111 and R112 are the same as or different from each other and are each a hydrogen atom or the like, and R113 is an alkyl group free from a fluorine atom or the like):

Abstract: An underground structure cover comprises a cover body (10) and a receiving frame (20) arranged so that the cover body is fitted in and supported by the receiving frame in the manner that an inclined surface (11) of the outer circumference of the body meets an inclined surface (21) of the inner circumference of the frame. The inclined surfaces (11, 21) each have an upper inclined surface (11a, 21a) and a lower inclined surface (11b, 21b), and the lower inclined surfaces (11b, 21b) are steeper than the upper inclined surfaces (11a, 21a). The body (10) is fitted in and supported by the part (20) at the upper inclined surfaces (11a, 21a) and the lower inclined surfaces (11b, 21b). By this, the body is prevented from being wedged into the frame too deeply and also from becoming inclined with respect to the frame or riding up.

Abstract: An underground structure cover comprises a cover body (10) and a receiving frame (20) arranged so that the cover body is fitted in and supported by the receiving frame in the manner that an inclined surface (11) of the outer circumference of the body meets an inclined surface (21) of the inner circumference of the frame. The inclined surfaces (11, 21) each have an upper inclined surface (11a, 21a) and a lower inclined surface (11b, 21b), and the lower inclined surfaces (11b, 21b) are steeper than the upper inclined surfaces (11a, 21a). The body (10) is fitted in and supported by the part (20) at the upper inclined surfaces (11a, 21a) and the lower inclined surfaces (11b, 21b). By this, the body is prevented from being wedged into the frame too deeply and also from becoming inclined with respect to the frame or riding up.

Abstract: A cover assembly includes a support frame (20) fixed to a utility access hole and a rounded cover (10) fitted into the support frame. The support frame is provided in its upper portion with an S-curved inner peripheral surface (20b) having a convex curved surface portion (21) and a concave curved surface portion (22) that continues to the convex curved surface portion and is formed thereabove. The cover has an S-curved peripheral surface (10b) that is substantially complementary in shape to the S-curved inner peripheral surface of the support frame. When the access hole is closed by the cover, the cover is smoothly fitted into the support frame due to a guide function of the S-curved inner peripheral surface of the support frame.

Abstract: A cover assembly includes a support frame (20) fixed to a utility access hole and a rounded cover (10) fitted into the support frame. The support frame is provided in its upper portion with an S-curved inner peripheral surface (20b) having a convex curved surface portion (21) and a concave curved surface portion (22) that continues to the convex curved surface portion and is formed thereabove. The cover has an S-curved peripheral surface (10b) that is substantially complementary in shape to the S-curved inner peripheral surface of the support frame. When the access hole is closed by the cover, the cover is smoothly fitted into the support frame due to a guide function of the S-curved inner peripheral surface of the support frame.