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光波長對木材劣化的影響
Effect of Light Wavelength on the Degradation of Wood
Abstracts
本研究係探討光波長對木材表面強化的影響，木材分別用波長＞220nm, ＞254 nm, ＞300 nm, ＞350 nm, ＞400nm及＞540nm六種光源照射後，以明亮度及顏色測定儀，紅外線光譜儀與紫外光譜儀分析木材表面變化情形。試驗結果顯示當木材受到含有紫外光光源照射後其表面會產生黃化，且木材主要成分之一的木質素首先遭受破壞，這種劣化程度隨著光源能量增強及照射時間增長而變劇；當木材受到可見光（波長＞400nm）光源照射後，木材表面產生白化，但是其化學組成份却未產生任何可偵測的化學變化。根據這些試驗結果得知光源中的紫外光是誘始木材表面劣化的主要因子。
Parallel abstracts
The effect of light wavelength on the degradation of wood was studied by investigating the color change and the chemical composition changes of wood surfaces. When wood was irradiated with light of wavelengths shorter than 350run, yellowing was observed on wood surfaces and lignin also preferentially underwent decomposition by ultraviolet light. The extent of degradation was directly proportional to the light energy irradiated and increased as a function of irradiation time. However, no chemical changes except photo-bleaching were detected when wood .was irradiated with visible light of wavelengths longer than 400nm. These findings imply that it is the ultraviolet wavelength rather than the-visible wavelength which causes the adverse degradation on wood surfaces.