Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a compressive stress CS (MPa) on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and DOL50%/DOLzero is 0.30 or more, where DOL50% (?m) is a depth at which the value of the compressive stress is 50% of the CS and DOLzero (?m) is a depth at which the value of the compressive stress is 0 MPa.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a stress depth DOLzero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 ?m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and CS×DOLzero, which is a product of the compressive stress CS on the outermost surface and the stress depth DOLzero (?m), is 4.8×104 or more.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, where a stress depth DOLzero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 ?m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and a central stress CT determined by using curve analysis is 55 to 300 MPa.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, in which, CS is 400 to 1400 MPa and CT×(T?2×DOLzero)/CS×DOLzero is 0.60 or more, where CS (MPa) denotes a compressive stress on an outermost surface of the compressive stress layer, DOLzero (?m) denotes a stress depth of the compressive stress layer at which the compressive stress is 0 MPa, CT (MPa) denotes a central stress determined by curve analysis, and T (?m) denotes a thickness of the substrate.

Abstract: A fuel cap capable of preventing a reduction in breathability in a housing due to a moistened adsorbent and appropriately discharging fuel vapor includes a housing including an inner space through which vapor generated in a fuel tank flows upward from below. A granular adsorbent is disposed in the inner space of the housing. A lower air-permeable layer is disposed below the adsorbent, and an upper air-permeable layer is disposed above the adsorbent. A lower porous member is disposed between the adsorbent and the lower air-permeable layer. The lower air-permeable layer, the lower porous member, and the upper air-permeable layer respectively have a porous structure. A density of the lower porous member is lower than a density of the lower air-permeable layer and a density of the upper air-permeable layer.

Abstract: A fuel cap capable of preventing a reduction in breathability in a housing due to a moistened adsorbent and appropriately discharging fuel vapor includes a housing including an inner space through which vapor generated in a fuel tank flows upward from below. A granular adsorbent is disposed in the inner space of the housing. A lower air-permeable layer is disposed below the adsorbent, and an upper air-permeable layer is disposed above the adsorbent. A lower porous member is disposed between the adsorbent and the lower air-permeable layer. The lower air-permeable layer, the lower porous member, and the upper air-permeable layer respectively have a porous structure. A density of the lower porous member is lower than a density of the lower air-permeable layer and a density of the upper air-permeable layer.