设立在美国国家档案馆的金属橱柜里贮存了30多亿件美国历史文献,其中包括美国移民和人口调查的文件、南北战争期间的防水墨块以及1920年美国驻日领事收到的信件,等等。这些文件经过许多年的贮存,其中数以百万计的文件已变得很陈旧,纸张因年代久远而容易破坏,纸张的边缘也因翻阅过多而磨损。最近有一批科学家组成的小组正在研究保持这些文献的方法。这个新组成的科学家国家研究委员会认为,这些历史文件应该用三种方法之中的一种方法保存。这三 More than 3 billion American historical documents were stored in the metal cabinets of the National Archives, including documents on U.S. immigration and censuses, water-proof ink sticks during the Civil War and letters received by consul in the United States in 1920, etc. Wait. After many years of storage of these documents, millions of documents have become obsolete, the paper is easily destroyed by age, and the edges of paper have also been worn down due to overviews. A group of scientists recently is studying ways to keep these documents. The newly formed National Research Council of Scientists believes that these historical documents should be preserved in one of three ways. These three