Polyanhydrides are one kind of biomaterial with characteristics of surface degradation and good biocompatibility.

聚酸酐是一类具有表面降解特性的生物医用高分子材料，具有良好生物相容性。

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Concerns include the degradation of surface and groundwater owing to poultry waste nutrients and pathogenic microorganisms.

令人担忧的问题包括家禽粪便养分和病原微生物造成的地表水和地下水退化。

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The results showed that UV radiation mainly led to crystal destruction and molecular degradation on the surface and recrystallization on the interior part of the sample.

结果表明，紫外光的照射主要导致聚甲醛试样表面层发生晶体破坏和无定形部分分子链降解，内层则主要发生非晶区重整结晶；

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The degradation of water quality in surface and groundwater systems is further exacerbating water scarcity and negatively impacting our natural environment and the ecosystem services and goods that it provides, jeopardizing food security and livelihoods.

UNESCO: World Water Day 22 March 2010: Clean Water for a Healthy World

The UNESCO Chair in The Development of a Sustainable Geoenvironment contributes to stalling and reversing the contamination and degradation of terrestrial systems and their surface and groundwater systems.

UNESCO: Chairs and UNITWIN Networks

Initially, the idea was to use plastic flexible displays (as evidenced by previous XO 3.0 renders), but degradation caused by the sun's UV rays and plastic's easily scratched surface forced the company to switch gears and use glass instead.

ENGADGET: OLPC's XO 3.0 tablet hands-on (video) Hands-on