Abstract: A quartz glass crucible (1) has a structure wherein a peak of a distribution of a total concentration of Na, K, and Ca in a depth direction from an inner surface (10i) of the crucible is present at a position deeper than the inner surface (10i). In an exemplary embodiment, the quartz glass crucible is capable of improving the yield of a silicon single crystal by suppressing peeling-off of brown rings.

Abstract: In an exemplary embodiment, a quartz glass crucible 1 includes: a straight body portion 1a having a cylindrical shape; a bottom portion 1b; and a corner portion 1c, in which a bubble content of an inner surface layer portion ranging from an inner surface to a depth 0.5 mm in an upper portion 1a1 of the straight body portion 1a is 0.2% to 2%, the bubble content of the inner surface layer portion in a lower portion 1a2 of the straight body portion 1a is more than 0.1% and not more than 1.3 times a lower limit of the bubble content of the upper portion 1a1, the bubble content of the inner surface layer portion in the corner portion 1c is more than 0.1% and 0.5% or less, and the bubble content of the inner surface layer portion in the bottom portion 1b is 0.1% or less.

Abstract: A quality-evaluated vitreous silica crucible for pulling silicon single crystal is provided, wherein an inner surface of the vitreous silica crucible has regions where surface defects including brown rings are to be generated when pulling silicon single crystal. The regions are distinguished using an infrared absorption spectrum or a Raman shift of the regions, wherein a position of each region and/or a density of the regions are/is specified.

Abstract: A quality-evaluated vitreous silica crucible for pulling silicon single crystal is provided, wherein an inner surface of the vitreous silica crucible has regions where surface defects including brown rings are to be generated when pulling silicon single crystal. The regions are distinguished using an infrared absorption spectrum or a Raman shift of the regions, wherein a position of each region and/or a density of the regions are/is specified.

Abstract: A method of manufacturing a vitreous silica crucible includes an inspection method comprising: a measurement step of measuring an infrared absorption spectrum or a Raman shift of a measurement point on an inner surface of the vitreous silica crucible; a determining step of predicting whether a surface defect region is generated or not in the measurement point based on an obtained spectrum to determine a quality of the vitreous silica crucible.

Abstract: A method of manufacturing a vitreous silica crucible includes an inspection method comprising: a measurement step of measuring an infrared absorption spectrum or a Raman shift of a measurement point on an inner surface of the vitreous silica crucible; a determining step of predicting whether a surface defect region is generated or not in the measurement point based on an obtained spectrum to determine a quality of the vitreous silica crucible.

Abstract: An inspection method of vitreous silica crucibles includes: a measurement step of measuring an infrared absorption spectrum or a Raman shift of a measurement point on an inner surface of the vitreous silica crucible; a determining step of predicting whether or not a surface-defect region occurs at the measurement point based on an obtained spectrum to determine a quality of the vitreous silica crucible.

Abstract: An inspection method of vitreous silica crucibles includes: a measurement step of measuring an infrared absorption spectrum or a Raman shift of a measurement point on an inner surface of the vitreous silica crucible; a determining step of predicting whether or not a surface-defect region occurs at the measurement point based on an obtained spectrum to determine a quality of the vitreous silica crucible.

Abstract: A closure for silica glass crucible to be mounted on an opening portion of a silica glass crucible is provided with a peripheral edge mounting portion closely adhered to an inner peripheral end of the opening portion.

Abstract: A closure for silica glass crucible to be mounted on an opening portion of a silica glass crucible is provided with a peripheral edge mounting portion closely adhered to an inner peripheral end of the opening portion.

Abstract: By providing a method capable of avoiding invasion of starting material powder for crucible into an inner face of the crucible, it is made possible to reliably avoid the invasion of foreign substances into a vitreous silica crucible until an actual use time of the crucible and to handle the crucible with no contamination. A cover 3 mounted onto an opening portion 2 of a vitreous silica crucible 1, comprising a flange portion 4 in close contact with an outer peripheral end 2a of the opening portion 2, is mounted onto the crucible 1.

Abstract: A closure for silica glass crucible to be mounted on an opening portion of a silica glass crucible is provided with a peripheral edge mounting portion closely adhered to an inner peripheral end of the opening portion.

Abstract: A lubricating system for use in a two-cycle engine having at least one valve pivotally mounted through bearings in the sidewall of an intake passage of a carburetor is disclosed which supplies lubricating oil directly on the sidewall of the intake passage to lubricate the valve bearings in order to prevent corrosion and sticking of the valve. The lubricating oil is delivered into the intake passage directly on the sidewalls upstream of the bearings so that the lubricating oil flows along these walls to assure adequate flow to the bearings. The lubricating oil may be delivered into the intake passage by supplying the oil directly through at least one of the bearings of the valve.