The skeletal density of four kinds of coal in different rank is determined by atomic distribution function of wide angle x-ray diffraction spectrum (WAXS) and a common method using hydrometer.

• 用x射线广角衍射原子分布函数方法测试了不同煤化程度煤的真密度，并与按常规方法（国家标准）测定的结果进行了对比。