Narrow disperse poly（ethyleneglycol dimethacrylate-co-4-vinylpyridine） （poly（EGDMA-co-4-VPy）） microspheres were prepared by distillation-precipitation copolymerization of ethyleneglycol dimethacrylate （EGDMA） ...Narrow disperse poly（ethyleneglycol dimethacrylate-co-4-vinylpyridine） （poly（EGDMA-co-4-VPy）） microspheres were prepared by distillation-precipitation copolymerization of ethyleneglycol dimethacrylate （EGDMA） and 4-vinylpyridine （4-VPy） with 2,2＇-azobisisobutyronitrile （AIBN） as initiator in neat acetonitrile. The polymer microspheres containing pyridyl group were then utilized as stabilizer for gold metallic colloids with the diameter around 7 nm, which were prepared by the in situ reduction of gold chloride trihydrate with sodium borohydride through the coordination of the pyridyl group on the gel layer and surface of the microsphere with the gold metallic nano-particles. The catalytic properties of the pyridyl- functionalized microsphere-stabilized gold metallic colloids and the behavior of the stabilized-catalyst for the recycling were investigated with reduction of 4-nitrophenol to 4-aminophenol as a model reaction.展开更多
In recent years, the modern methods of multi-element analysis of precious metals have attracted wide attention in scientific research and industry. The application and development in the decomposition of samples, sepa...In recent years, the modern methods of multi-element analysis of precious metals have attracted wide attention in scientific research and industry. The application and development in the decomposition of samples, separation and enrichment, and modern instrumental analysis of the platinum-group elements (PGEs) and gold in geological and environmental samples have been reviewed. Finally, the tendency of analysis of precious metals is also prospected.展开更多
Geological and geochemical studies and experiments on mineralization indicate that the source bed of the La' erma gold deposit in the south subbelt of the western Qinling Mountains is hydrothermal cherts in the Ca...Geological and geochemical studies and experiments on mineralization indicate that the source bed of the La' erma gold deposit in the south subbelt of the western Qinling Mountains is hydrothermal cherts in the Cambrian Taiyangding Group. Organic geochemical study of the cherts shows that the organic precursors intimately associated with gold are marine bacteria and algae. The gold content in chert,is positively correlated with the amount of bacterial and algal microfossils, and simulation experiments on biomineralization of modern bacteria and algae indicate that bacteria and algae played an important role in the formation of the La' erma gold deposit.展开更多
All gold deposits in North-Eastern Hunan are of vein type, and hosted by the low grade metamorphic rocks of Lengjiaxi Group of the Middle Proterozoic Era. Their geochemical characteristics show that the ore-forming ma...All gold deposits in North-Eastern Hunan are of vein type, and hosted by the low grade metamorphic rocks of Lengjiaxi Group of the Middle Proterozoic Era. Their geochemical characteristics show that the ore-forming materials came from their host rocks. Oreforming fluids are rich in CO2 and SO2-4,with high Na+/K+ ratio, low Cl - and varied δ18O and δD values, showing that they are from multisources. These gold deposits were formed by a series of tectonic-thermal events which reworked the Lengjiaxi Group. There are two main stages of tectonic-thermal events: the Wulingian Period forming the auriferous quartz veins by syntectonic metamorphic differentiation, and the Indosinian-Yanshanian peroid causing re formation and enrichment of the former auriferous quartz veins.展开更多
Strata of different geological periods extensively outcrop in western Guang-dong Province, but most gold deposits are restricted to the Middle-Late Proterozoic Yunkai Group and the Cambrian Bacun Group,showing obvious...Strata of different geological periods extensively outcrop in western Guang-dong Province, but most gold deposits are restricted to the Middle-Late Proterozoic Yunkai Group and the Cambrian Bacun Group,showing obvious strata-boun character-istics .Gold abundance and trace element geochemistry of the Yunkai and Bacun Groups are compared with those of the Ordovician and Silurian strta.The Yunkai Group is considered to be the source strata for gold mineralization in the region.展开更多
基金This work was supported in part by the National Science Foundation of China(No.20504015)the Opening Research Fund from the State Key Laboratory of Polymer Chemistry and Physics,Chinese Academy of Sciences(No.200613).
文摘Narrow disperse poly（ethyleneglycol dimethacrylate-co-4-vinylpyridine） （poly（EGDMA-co-4-VPy）） microspheres were prepared by distillation-precipitation copolymerization of ethyleneglycol dimethacrylate （EGDMA） and 4-vinylpyridine （4-VPy） with 2,2＇-azobisisobutyronitrile （AIBN） as initiator in neat acetonitrile. The polymer microspheres containing pyridyl group were then utilized as stabilizer for gold metallic colloids with the diameter around 7 nm, which were prepared by the in situ reduction of gold chloride trihydrate with sodium borohydride through the coordination of the pyridyl group on the gel layer and surface of the microsphere with the gold metallic nano-particles. The catalytic properties of the pyridyl- functionalized microsphere-stabilized gold metallic colloids and the behavior of the stabilized-catalyst for the recycling were investigated with reduction of 4-nitrophenol to 4-aminophenol as a model reaction.
文摘In recent years, the modern methods of multi-element analysis of precious metals have attracted wide attention in scientific research and industry. The application and development in the decomposition of samples, separation and enrichment, and modern instrumental analysis of the platinum-group elements (PGEs) and gold in geological and environmental samples have been reviewed. Finally, the tendency of analysis of precious metals is also prospected.
基金This research was supported by the Youth Foundation of National Natural Science of China grant 49503048.
文摘Geological and geochemical studies and experiments on mineralization indicate that the source bed of the La' erma gold deposit in the south subbelt of the western Qinling Mountains is hydrothermal cherts in the Cambrian Taiyangding Group. Organic geochemical study of the cherts shows that the organic precursors intimately associated with gold are marine bacteria and algae. The gold content in chert,is positively correlated with the amount of bacterial and algal microfossils, and simulation experiments on biomineralization of modern bacteria and algae indicate that bacteria and algae played an important role in the formation of the La' erma gold deposit.
文摘All gold deposits in North-Eastern Hunan are of vein type, and hosted by the low grade metamorphic rocks of Lengjiaxi Group of the Middle Proterozoic Era. Their geochemical characteristics show that the ore-forming materials came from their host rocks. Oreforming fluids are rich in CO2 and SO2-4,with high Na+/K+ ratio, low Cl - and varied δ18O and δD values, showing that they are from multisources. These gold deposits were formed by a series of tectonic-thermal events which reworked the Lengjiaxi Group. There are two main stages of tectonic-thermal events: the Wulingian Period forming the auriferous quartz veins by syntectonic metamorphic differentiation, and the Indosinian-Yanshanian peroid causing re formation and enrichment of the former auriferous quartz veins.
文摘Strata of different geological periods extensively outcrop in western Guang-dong Province, but most gold deposits are restricted to the Middle-Late Proterozoic Yunkai Group and the Cambrian Bacun Group,showing obvious strata-boun character-istics .Gold abundance and trace element geochemistry of the Yunkai and Bacun Groups are compared with those of the Ordovician and Silurian strta.The Yunkai Group is considered to be the source strata for gold mineralization in the region.
