The transition point of CDW is near to 30k accompanying with the superconductiviting phenomenon. By analyzing the XRD patterns and the r-T curve of NbSe_2,the reappearance of the SbSe_2 crystals at low temperature are discused.

• 测试出NbSe2晶体的临界温度为7.；2K；30 K附近发生CDW转变；出现了CDW和超导电性共存的现象；通过分析NbSe2晶体的r-T曲线和NbSe2晶体的XRD图谱；讨论了低温下NbSe2晶体的重入现象。