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介绍了一种用极谱催化波间接测定硫酸根的方法,讨论了实验条件和干扰因素.方法简便,选择性好,测定范围宽. 相似文献
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The tribological properties of perfluoro and non-perfluoro alkylsilane molecular films were investigated and compared detailedly.
Their surface properties were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact
angle (CA) measurement. A ball-on-disk tribometer was used to study the frictional properties of these alkylsilane monolayers.
The experimental results reveal that the alkylsilane molecular films are good candidates to decrease friction and they have
good capability to endure rigorous shear forces. Perfluoro alkylsilane molecular films are bonded better with the Si substrate
than the simple hydrocarbon ones. The effects of sliding velocity and normal load on friction coefficient are evident and
the friction coefficient increases with the increase of the sliding velocity. However, friction coefficient decreases with
the increase of normal load initially and then increases, indicating there exists a critical normal load for the load effect.
Funded by the National Natural Science Foundation of China (No.50730007 and 50805086), the Foundation of Tsighua Basic Research,
and the National Key Basic Research Program of China(No. 2007CB607604) 相似文献
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