density log密度测井densityn.密度；浓度；比重density functinoal theory密度泛涵理论Density Difference Theory密度法density of surface charge面电荷密度density of state function能态密度函数density of wood substance木材密实度density-stratified flow密度分层流density of infected users用户感染密度density-change equation密度变化方程density-related process密度关联过程Density fauctional theory密度泛函理论