fix：

（1）打印读取有误的文件名；
（2）doas算法计算过程中负值置零；

sif_methods.py

@@ -237,6 +237,10 @@ def doas(data,wl_range,band=760):
         print(data.Measures[i].values)
         sky_spec = data.sky[i].values
         veg_spec = data.veg[i].values
+
+        veg_spec[np.where(veg_spec < 0)] = 0
+        sky_spec[np.where(sky_spec < 0)] = 0
+
         _X = np.concatenate([_ref_base,(_hf/(veg_spec+0.000001111)).reshape(1,-1)]).T
         _y = np.log(veg_spec+0.000001111) - np.log(sky_spec+0.00000111111)
         _B = np.linalg.lstsq(_X,_y,rcond=-1)