Most page elements have a boxy contour, so this variation will create some unique contrast.
许多页面元素都采用的是框式轮廓，因而这些变化会营造一些独特的对比效果。
2
The lateral inhomogeneity and the variation of density contrast with depth in the crust and their effects on the inversion of gravity field are discussed.
XPCI of low-absorption objects or little absorption variation objects showed some structure that could not be demonstrated in absorption contrast images.