Sulfonated ordered mesoporous carbon (SOMC) has been used as a new catalytic material in heterogeneous reactions for it can replace many conventional homogeneous acid catalysts. At present, it was obtained mainly thro...
详细信息
ISBN:
(纸本)9783037856666
Sulfonated ordered mesoporous carbon (SOMC) has been used as a new catalytic material in heterogeneous reactions for it can replace many conventional homogeneous acid catalysts. At present, it was obtained mainly through sulfonating the surface of mesoporous carbon by post-processingmethod, which contained relatively complex process and rigorous condition. In this work, SOMC was prepared directly via pre-processing method. The structure and morphology of SOMC were characterized by means of FT-IR, XRD, TEM and BET, the catalytic performance was investigated by the acetalization reaction between benzaldehyde and n-butyl alcohol as a model reaction. The result showed that SOMC has excellent high surface area and uniform mesostructure when the mole ratio of phenolic resin: sulfuric acid: F127 was 1: 2: 0.0238 and carbonization temperature was 600 degrees C. In the acetalization reaction, the yield of acetal of using SOMC material as catalyst was 87.1%, much higher than that of using HY zeolite, which shows that the SOMC has excellent catalytic property in the catalytic reaction of acetalization.
A new pre-processing method for pitch smoothing is proposed. This methodology modifies the residual speech signal such that the pitch period evolves more smoothly without distorting perceptual speech quality. Thus, pi...
详细信息
A new pre-processing method for pitch smoothing is proposed. This methodology modifies the residual speech signal such that the pitch period evolves more smoothly without distorting perceptual speech quality. Thus, pitch can be effectively interpolated and transmitted only once per frame while presenting the long-term correlation of speech signal and maintaining the perceptual speech quality.
A new pre-processing method called independent interference reduction (IIR) is proposed. It is based on modelling of the interferences by use of principal component analysis (PCA) using samples containing no variation...
详细信息
A new pre-processing method called independent interference reduction (IIR) is proposed. It is based on modelling of the interferences by use of principal component analysis (PCA) using samples containing no variation in the parameter of interest. This is followed by subtraction of the modelled effects from the calibration matrix. It is useful in cases where the parameter of interest gives only minor contributions to the calibration matrix and where, at the same time, samples not containing variation in this parameter are easy to obtain. In such a case the method reduces the number of reference analyses required for establishing a reliable calibration. When applied to acetone determination in milk samples by use of Fourier transform infrared (FT-III) spectroscopy, the method provides a treatment of the data which yields more stable models in the subsequent calibration step. Copyright (C) 2000 John Wiley & Sons, Ltd.
暂无评论