Crystal structure and fluorescence properties for corbicula japonica shells were researched for the purpose of an application to functional materials. Corbicula japonica shells were heat-treated at 200 to 1000°C. The crystal structure of the specimens heat-treated less than 300°C was aragonite CaCO₃, that heat-treated at 400~600°C was calcite CaCO₃ and that heat-treated at 800~1000°C was CaO. All the specimens showed a fluorescence property with the broad peak at 400~500 nm, and the specimens heat-treated at 800~1000°C showed orange color fluorescence with the peak at 594 nm attributed to Mn activator.

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The fluorescence samples (CaO matrix and Mn activator) was prepared by firing corbicula japonica shells at 900°C, where the origin places of those were the lake Abashiri, the lake Ogawara, the Kisogawa, the lake Ju-san, the lake Shinji and the lake Hinuma. All the samples showed orange color fluorescence with the peak at 594 nm. The fluorescence intensity increased with increase of the Mn/Ca ratio of the samples except the sample of the lake Ju-san.

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Stress distribution in multi-step ion-exchanged glass could not be measured accurately by conventional non-destructive stress measurement instrument and method. Therefore, by applying improved algorithm, stress distribution in 2-step ion-exchanged glass was evaluated. By comparing the results with 3 destructive measurement methods, it was confirmed that the measured stress value and the shape of distribution corresponded to the methods. Besides, it was shown that the accuracy of the new method was equal to the accuracy of conventional method for common 1-step ion-exchanged glass. Thus, it was confirmed that this developed method is applicable for the practical use.

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