铝铁硅钙壳是土壤表面或其附近的一层硬物。

Duricrust is a hard layer on or near the surface of soil.

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更沉重的壳：锈蚀斑斑的波浪形铁，坍塌的墙，或是留在好望角巨大的混凝土块，人工做的悬崖，用古代的金属丝做成的胡子等等。

Heavier coverings: rusting corrugated iron, broken-down walls, or at Hope cove giant concrete blocks, mimicking the cliffs, whiskered with antique wire.

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本文以二氧化硅为壳层材料，以纳米铁以及羰基铁粒子为核层材料，制备一种新型的吸收剂粒子。

This text attempts to regard silica as shell materials, regard nanometer iron and carbonyl iron particle as core materials to prepare a kind of new-type absorbent.

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