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A silver nanoparticle composite based on modified polyallylamine has been synthesized by a simple chemical route and its catalytic activity has been tested for alkyne–azide cycloaddition reaction. This silver nanocomposite shows an excellent catalytic activity at 80 °C for the synthesis of 1,4-disubstituted 1,2,3-triazole by alkyne–azide cycloaddition. The solid silver nanocomposite catalyst was characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffractometry and thermogravimetric analysis. The developed catalyst is stable in air, easy to prepare and can be recovered easily and reused ten times without a significant decrease in activity. 相似文献
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为改善液晶电视机面壳注塑模具点浇口处因长期料流冲击、磨损造成的缺陷,对模具成型面进行局部表面热处理,提高局部材料的硬度和耐磨性。从注塑成型模具浇口结构和对模具材料的分析,说明改善液晶电视机面壳注塑模具点浇口具体处理的方法和产生的效果。 相似文献
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Cheng Tan Feng-Shou Liu Dong-Sheng Shen Tao Cheng Zong-Zhou Zhou 《Catalysis Letters》2011,141(9):1332-1337
Abstract
In this letter, a series of bulky N-acyl-pyridylbenzamidine ligands were synthesized and characterized. Under the optimized reaction conditions, these bulky ligands were applied to catalyze Suzuki–Miyaura reactions of various aryl bromides and chlorides. The desired biaryl products were obtained in good to high yields. 相似文献8.
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建立了顶空固相微萃取—气相色谱—质谱(headspace solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)结合自动解卷积技术检测阿胶中挥发性物质的分析方法。以总峰面积和总出峰数为考察指标,通过单因素和正交试验对萃取条件进行优化,以期得到HS-SPME-GC-MS分析阿胶挥发性物质的较优条件。结果显示,萃取温度对总出峰数和总峰面积的影响较大,所得优化萃取条件为样品量5g、50/30μm DVB/CAR/PDMS萃取头、萃取温度70℃、平衡时间10 min、萃取时间50 min、解吸时间5min。该条件下,鉴定出阿胶挥发性成分41种,分别为吡嗪类10种、醛类8种、酯类5种、酮类6种、13种其他类化合物,其中相对含量较高的为吡嗪类48.95%和醛类26.37%。挥发性成分绝对峰面积的相对标准偏差的平均值为6.25%,该方法重复性较好。 相似文献