The crystallinities of bamboo-based carbon filaments have been examined by Raman spectroscopy as a nondestructive means of analysis of the historical lamp (ca. 1890s) manufactured by Ichisuke Fujioka of Japan, and the results have been compared with results from the study of Edison's lamp (ca. 1889) and replica lamps produced in 1979. The crystallinities for the three carbon filaments have been evaluated in terms of the intensity ratio ID/IG, where ID is the intensity at 1350 cm(-1) for the D band originating from the defect of graphite and IG is the intensity at 1585 cm(-1) for the G band due to the stretching vibration of graphite layers. The ratios obtained are 0.3-0.4, 0.28-0.3, and 0.25-0.28 for the Fujioka, Edison, and replica lamps, respectively. The Raman spectrum of the bamboo-based carbon filament produced by thermal pyrolysis at 1273 K in a nitrogen atmosphere is significantly different from those of filaments inside the incandescent lamps. The raw bamboo filament was analyzed by ultraviolet (UV) Raman spectroscopy using an excitation wavelength of 325 nm from a HeCd laser to avoid the strong interference due to photoluminescence. An intense peak at 1585 cm(-1) was recognized, which was ascribed to the C=C bond vibration for the lignin component in the bamboo. The upper shift of the D band for the carbon filament pyrolyzed at 1273 K was confirmed by varying the excitation wavelength at 514.5 nm to 325 nm, and this behavior was interpreted on the basis of the double resonance Raman scattering mechanism.
The strength degradation of steel adhesive joint in water environment was investigated. A model is proposed in which the process of progressive decrease in joint strength due to water uptake is considered as that of progressive growth of an apparent crack at the joint interface, and the strength degradation of adhesive joint can be analysed on the basis of fracture mechanics. It was found that in the specimens immersed in water for the same duration of time, the depth of the apparent crack increased with increasing water temperature, while the water concentration at the tip of respective crack was nearly the same. The fracture strength after immersing the joint in water at various temperatures was determined as a function of a single variable of Dt. The effect of side diffusion on the joint strength is not negligible in the case of longer immersion, especially at higher temperatures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.