This standard specifies the use of X-ray small-angle scattering effects side be satisfied wood wooden Du degree distribution method. This standard applies to the determination of capsules size I nm ~ 300 nm in the range of particle size distribution of the powder, the inorganic, organic and biological macromolecules off glue determination of particle size, but also for implementation. When a deviation from the spherical shape of the powder particles, the method gives the equivalent spherical diameter of the scattering. This method does not apply to shun grains composed of different materials mixed powder, generally does not apply to a powder emblem holes exist, but emblem nanoscale pore size and smooth grain (or frame) size is 0. 5 ��m or more, can be used to set the appropriate pore size distribution side.