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  • Author or Editor: Wensheng Wang x
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Abstract  

Large deviation results for Gaussian processes are presented. As an application, we obtain a functional limit result for small increments of a fractional Brownian motion. Lvy's modulus of continuity for a fractional Brownian motion is obtained as a special case.

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Abstract  

Small ball probability is estimated for a Brownian motion in l p. As an application we establish the modulus of non-differentiability of a Brownian motion in l p.

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Abstract  

A series of phosphorus modified Si-MCM-41 catalysts prepared via the impregnation method were used for the vapor-phase Beckmann rearrangement of cyclohexanone oxime to caprolactam. The catalysts were characterized by XRD, N2 adsorption, FT-IR, and NH3-TPD. The results indicated that weak acid sites increased with P content, leading to enhanced catalytic activity. The catalyst with Si/P mol ratio of 25 showed best performance at 633 K. The conversion of cyclohexanone oxime and the selectivity for caprolactam were 92.7 and 64.2%, respectively. The P–OH groups are main active sites for the Beckmann rearrangement. Grafting acid hydroxyl groups to cover the Si–OH groups may be a good way to improve the selectivity for this reaction.

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