问题的提出1960年,R. E. Burton和R. W. Kebler根据J. O. Bernald将文献老化(Obsolescence)过程与放射性物质衰变过程相类比的想法,提出了著名的描述文献老化过程的经验公式: y=1-((a/e~x)+(b/e~(2x))) …(1) (a+b=1)其中:x代表以10年为单位的时间变量(即被引文献的出版年龄),y代表被引文献的累积百分数(Cumulated Percentage) (即被引文献按其出版年龄累积的相对数量), PROBLEM PROBLEMS In the 1960’s, RE Burton and RW Kebler proposed well-known empirical equations describing aging processes based on JO Bernald’s idea of ​​obsolescence and decay of radioactive material: y = 1 - ((a (1) (a + b = 1) where: x represents the time variable in 10 years (ie, the published age of the cited documents), y Represents Cumulated Percentage of Cited Documents (ie, the relative number of citation articles accumulated by their publication age),