(1)密度与相对密度(Density and relative density) 密度是指物质单位体积内所含的质量，简言之是质量与体积之比，其单位是百万克／米3(Mg／m3)..
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体育课的密度可分为一般密度和专项密度两类，与之相对应地形成了两类密度的测定方法。
The density of PE can be divided into general density and specialty density, in accordance with it, the two methods of measuring them are formed.
油漆薄木贴面中密度纤维板TVOC释放量与薄木贴面中密度纤维板差异不大，甲醛释放量很少，苯系物相对较多。
Less formaldehyde and more benzene released from spray MDF veneered veneer that had little difference in TVOC emission comparing with MDF veneered veneer.
当新型无银触头材料的相对密度与银氧化物触头材料的相对密度相同时，两者电阻率相当，而其硬度高于银氧化物触头材料的；
The properties of the material, such as density, hardness, resistivity, arc resistance and temperature characteristics, are all similar to those of the silver oxidization contact materials.
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