The biomineralization process of iron oxidizing bacteria and its influence on accumulation of metals were investigated by modern biological observation techniques (i.e., SEM and TEM) and geochemical methods, in coasta...The biomineralization process of iron oxidizing bacteria and its influence on accumulation of metals were investigated by modern biological observation techniques (i.e., SEM and TEM) and geochemical methods, in coastal area of Zhoushan Island, Zhejiang province where a thick ancient wood layers were buried, Results show that the iron mud samples mainly contain Leptothrix-like sheaths and Gal-lionella-like stalks, which are known as neutrophilic iron-oxidizing bacteria. These two bacteria are present as obviously different abundance in two sampling sites, which may be regulated by the geo-chemistry of seepage water. The biomineralization product of iron oxidizing bacteria is ferrihydrite, a poorly ordered iron oxide, and formation of amorphous mineral is affected by the factors of bacteria, minor Si and temperature preventing any further transformation into more crystalline phases. Organic functional groups, extracellular polymers and surface charges can provide favorable nucleation sites or template for formation of iron precipitates on the bacterial surface. The mineralization process of the iron oxidizing bacteria is divided into different stages, i.e., extracellular mineralization, intracellular mineralization and the whole cell mineralization. Furthermore, due to BIOS containing the bacterial organic matter, the accumulation capacity of metals specially Fe and Co is highly increased, suggest-ing that BIOS exert a degree of controlling in the cycling of metal elements in seepage area.展开更多
本文探索了一种能用于大规模 MOS 集成电路的栅氧化技术—补充后的两步 TCE法。笔者采用该法,在一般工厂的工艺条件下,制得了90%以上的 MOS 电容,击穿电场大于6MV/cm,可动电荷密度约为10^(10)cm^(-2),固定电荷密度约为10^(11)cm^(-2)的...本文探索了一种能用于大规模 MOS 集成电路的栅氧化技术—补充后的两步 TCE法。笔者采用该法,在一般工厂的工艺条件下,制得了90%以上的 MOS 电容,击穿电场大于6MV/cm,可动电荷密度约为10^(10)cm^(-2),固定电荷密度约为10^(11)cm^(-2)的优质超薄氧化层。展开更多
基金the Important Direction Project of the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No.KZCX3-SW-151)China Post-doctoral Science Foundation (Grant No.20060400723)
文摘The biomineralization process of iron oxidizing bacteria and its influence on accumulation of metals were investigated by modern biological observation techniques (i.e., SEM and TEM) and geochemical methods, in coastal area of Zhoushan Island, Zhejiang province where a thick ancient wood layers were buried, Results show that the iron mud samples mainly contain Leptothrix-like sheaths and Gal-lionella-like stalks, which are known as neutrophilic iron-oxidizing bacteria. These two bacteria are present as obviously different abundance in two sampling sites, which may be regulated by the geo-chemistry of seepage water. The biomineralization product of iron oxidizing bacteria is ferrihydrite, a poorly ordered iron oxide, and formation of amorphous mineral is affected by the factors of bacteria, minor Si and temperature preventing any further transformation into more crystalline phases. Organic functional groups, extracellular polymers and surface charges can provide favorable nucleation sites or template for formation of iron precipitates on the bacterial surface. The mineralization process of the iron oxidizing bacteria is divided into different stages, i.e., extracellular mineralization, intracellular mineralization and the whole cell mineralization. Furthermore, due to BIOS containing the bacterial organic matter, the accumulation capacity of metals specially Fe and Co is highly increased, suggest-ing that BIOS exert a degree of controlling in the cycling of metal elements in seepage area.
