中文摘要：

对于微量沉积物,利用扫描电镜获得的颗粒图像统计粒度参数是一条有效的途径,但需要解决被统计颗粒的最小样本量这一基本问题。使用北京市区降尘、中国北方的淡黑钙土和栗钙土3种微量样品,利用S-4800型扫描电镜获得的图片,对颗粒平均粒径、标准差和标准误,以及偏度和峰态等粒度参数进行了统计分析,旨在确定不同平均粒径的微量样品的最小统计样本量。结果表明：对于平均粒径约25μm的降尘样品,最小样本量为800;平均粒径100μm的淡黑钙土,最小样本量为1 100;平均粒径约180μm的栗钙土,最小样本量为1 200。

英文摘要：

It is an effective way for micro-samples of sediments to derive the grain size parameters by suing field emission scanning electron microscope（FESEM）,but the key issue of the minimum sample size needs to be solved.The three micro-samples were used,which were dustfall collected in Beijing,light chernozem soil and chestnut soil collected in the northern China respectively;besides,the parameters of mean particle size,standard deviation and standard error,skewness and kurtosis were used as a basis for evaluation.The aim of this study was to use particle images obtained by FESEM to determine the minimum sample size of different mean particle size of micro-samples.The results showed that the minimum sample size of the dustfall with the mean particle size about 25μm was 800 particles,the minimum sample size of the light chernozem with the mean particle size about 100μm was 1 100 particles,and the minimum sample size of the chestnut with the mean particle size about 180μm was 1 200 particles.