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One-pot Synthesis of Isoxazolines Using Soluble Polymer-supported Acrylates

Chinese Chemical Letters 2005年第4期16卷 440-442页

作者： LanTAO pengfeizhang YiXinGU DepartmentofChemistry HangzhouNormalCollegeHangzhou310036

An efficient and rapid parallel liquid-phase synthesis of isoxazolines has been reported. The one-pot three-component reaction of polyethylene glycol-supported acrylates, aldehydes and hydroxylamine hydrochloride in the presence of chloramine-T in methanol gave the corresponding PEG-supported isoxazolines, which can be cleaved from the support under mild condition to afford isoxazolines in good yields (>80%) and high purities (>86%).

关键词： Isoxazolines 1 3-dipolar cycloaddition soluble polymer liquid-phase synthesis polythylene glycol.

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Automated Detection of Contaminated Radar Image Pixels in Mountain Areas

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Advances in Atmospheric Sciences 2008年第5期25卷 778-790页

作者：刘黎平 QinXU pengfeizhang ShunLIU State Key laboratory of Severe weather Chinese Academy of Meteorological Sciences Beijing 100081 NOAA/National Severe Stolons Laboratory Nonnan Oklahoma CIMMS University of Oklahoma Norman Oklahoma

In mountain areas, radar observations are often contaminated （1） by echoes from high-speed moving vehicles and （2） by point-wise ground clutter under either normal propagation （NP） or anomalous propagation （AP） conditions. Level Ⅱ data are collected from KMTX （Salt Lake City, Utah） radar to analyze these two types of contamination in the mountain area around the Great Salt Lake. Human experts provide the ＂ground truth＂ for possible contamination of either type on each individual pixel. Common features are then extracted for contaminated pixels of each type. For example, pixels contaminated by echoes from high-speed moving vehicles are characterized by large radial velocity and spectrum width. Echoes from a moving train tend to have larger velocity and reflectivity but smaller spectrum width than those from moving vehicles on highways. These contaminated pixels are only seen in areas of large terrain gradient （in the radial direction along the radar beam）. The same is true for the second type of contamination - pointwise ground clutters. Six quality control （QC） parameters are selected to quantify the extracted features. Histograms are computed for each QC parameter and grouped for contaminated pixels of each type and also for non-contaminated pixels. Based on the computed histograms, a fuzzy logical algorithm is developed for automated detection of contaminated pixels. The algorithm is tested with KMTX radar data under different （clear and rainy） weather conditions.

关键词： radar data quality control membership function point-wise ground clutter moving vehicle echoes

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