論来自震源上方分界面的二次地震波的干涉現象

空气或風化了的地表层具有較小的波阻抗,其下則为具有較高波阻抗的致密介質,因而地表面或低速带的底面是两个波阻抗数值相差悬殊的介質的分界面。当地震波入射到这样的一个分界面上时,就有可能产生反射波。这种情况在天然地震（此时,首次的反射系来自地表面）以及勘探地震的实际工作中是会碰到的。     

Hyper-spectrum models for monitoring water quality in Dianshan Lake,China

The correlation between water quality parameters and hyper-spectral reflectance is studied with models established for each parameter and applied in Dianshan Lake, in the upstream of the Huangpu River running through Shanghai, China. Models are for dissolved oxygen (DO in mg/L): R720/R680 = 20.362×(R720/R680)2-31.438×(R720/R680)+19.156; for turbidity (NTU): R*714.5 = 206.07× (R*714.5)2-582.5×R*714.5 + 423.24; and for total phosphorus (TP in mg/L): R*509.5 = 16.661× (R*509.5)2-32.646×R*509.5+16.116. The R2 values are 0.770 8, 0.660 4 and 0.738 7, respectively, showing strong positive relationships. The models were then applied to assess water quality of different times. Results are quite satisfactory for some samples.