1.1 本规程的目的是介绍计算作为直方图数据给出的尺寸分布的平均尺寸和标准偏差的程序（参见规程 图1617 ). 假设颗粒大小为等效球体的直径，例如等效（面积/表面/体积/周长）直径。 1.2 平均尺寸/直径根据力矩比（M-R）定义系统定义。 2. , 3. , 4. 1.3 以国际单位表示的数值视为标准值。本标准不包括其他计量单位。 1.4 本标准并不旨在解决与其使用相关的所有安全问题（如有）。 本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 5.1 根据力矩定义的平均颗粒直径- 比值（M-R）系统由粒径分布的两个力矩之间的比值导出。

1.1 The purpose of this practice is to present procedures for calculating mean sizes and standard deviations of size distributions given as histogram data (see Practice E1617 ). The particle size is assumed to be the diameter of an equivalent sphere, for example, equivalent (area/surface/volume/perimeter) diameter. 1.2 The mean sizes/diameters are defined according to the Moment-Ratio (M-R) definition system. 2 , 3 , 4 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Mean particle diameters defined according to the Moment-Ratio (M-R) system are derived from ratios between two moments of a particle size distribution.