Smoke is a simple and effectual means of laser passive interference.The wave absorption property of nano-graphite as interference material of smoke screen was analyzed.Under insufflating different mass of nangraphite in a smoke chamber,the relation curves between transmission rate of 1.06μm and 10.6μm laser and time were tested,and with method of weighing dialyser the mass concentration was measured in different moments.So the average mass extinction coefficients of nano-graphite to 1.06μm and 10.6μm laser ...