正因子 meaning in Chinese

positive divisor

1 mark ) how many positive integers less than 500 have exactly 15 positive integer factors
1分)小于500的正整数中有多少个刚好有15个正因子？
A rapid , simple method has been developed for determination of ammonium perchlorite by using formaldehyde . this experiment proved that this method saved measuring time , raised speed and efficiency
摘要实验证明甲醛法测定铵盐含量，只要准确测定出较正因子对结果加以校正，是能够直接使用未经蒸馏去除甲醇的甲醛溶液而测定结果不存在显著差异，本方法简单、快速。