As it ages, white paper turns a distinctive yellow. But why? To find out, scientists artificially aged modern paper to reveal the changes on the molecular level. The research is in the journal Physical Review Letters.
隨著年代的久遠(yuǎn),白紙會(huì)明顯發(fā)黃。這是為什么呢?為了尋找答案,科學(xué)家人為地將現(xiàn)代的白紙老化以揭示其分子水平出現(xiàn)的變化。這項(xiàng)研究成果刊登在《物理評(píng)論通訊》上。
For 48 days, three unbleached paper samples aged rapidly in reactors that simulated different environmental conditions. The researchers then compared the artificially aged samples to the real deal: three pieces of paper crafted in 15th century Europe. This technique allowed them to gauge the types and amounts of changes going on.
在48天的時(shí)間里,三個(gè)原色紙張樣品在三個(gè)模擬不同環(huán)境條件的反應(yīng)堆中迅速老化。然后,研究人員比較了人為老化的紙張和三張15世紀(jì)歐洲的紙片之間的區(qū)別。這種方式可以讓他們判斷出這些紙張?jiān)陬愋秃蛿?shù)量上所發(fā)生的變化。
About 90 percent of the weight of old paper is cellulose, the sturdy material that makes up plant cell walls. But over time cellulose fibers oxidize. The process modifies parts of various molecules and turns them into what are called chromophores, which absorb light.
舊紙張重量的約90%來自纖維素,這是構(gòu)成植物細(xì)胞壁的堅(jiān)固材料。但隨著時(shí)間的推移,這種纖維素會(huì)逐漸氧化。這個(gè)過程會(huì)讓各種分子發(fā)生改性變化并將其轉(zhuǎn)化成染色體,而染色體會(huì)吸收光線。
White paper is white because it reflects all colors of light. Aging paper filled with chromophores reflects wavelengths that make it look yellow. The non-destructive technique used in this study could inform research to preserve and even whiten ancient texts and art. And give paper conservation abrighter outlook.
白紙之所以顯出白色因?yàn)樗梢苑瓷涓鞣N光線。而充滿了染色體的年代久遠(yuǎn)的紙張則可以反射那些使它看起來顯示黃色的波長。這項(xiàng)研究中使用的非破壞性技術(shù)有助于研究如何保持甚至將古代典籍和作品重新亮白。這對(duì)紙張保護(hù)而言是一個(gè)光明的前景。
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