994 resultados para 195-1200A


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浙江天(天台)-嵊(嵊县)地区是东南沿海中生代火山岩区Au、Ag及多金属成矿带的一部分,近年来发现多处具有工业意义的贵金属矿床。其矿床特征可以同世界上以火山岩为主岩的冰长石-绢云母型浅成低温热液贵金属矿床类比。具有高Ag、Pb、Zn(Au、Cu)丰度的前震旦纪陈蔡群变质岩和早白垩纪朝川组火山岩系是矿源层。矿床产于火山岩系中;围岩蚀变发育,硅化、绢云母化、伊利石化、菱锰矿化、冰长石化以及似青盘岩化与矿化有关。矿床元素垂直分带由浅部至深部为Au、Ag、Zn-Ag、Pb、Zn-Pb、Zn、Cu。菱锰矿的含Fe、Ca量与Ag矿化具有消长关系,菱锰矿含Fe高对Ag(Au)矿化有利。成矿流体为低盐度的NaCl-H_2O体系,富Na酸性(pH = 4.5)是该体系的特征。成矿流体来源以火山岩浆热液为主,有大气降水加入形成混合流体。硫、碳质来自火山岩浆。而成矿有用元素则来自大陆地壳的Ag、Pb、Zn (Au、Cu)高丰度值的陈蔡群或早白垩纪朝川组。成矿温度195 ℃ ~ 250 ℃及135 ℃±;成矿时代74 * 10~6年 ~ 105 * 10~6年,属晚白垩纪;成矿压力350 ~ 500 bar。成矿构造环境为大陆裂谷发展初期。矿床成因类型可确定为浅成中低温火山岩浆混合热液贵金属矿床。

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A novel method for the determination of N-acetylneuraminic acid (NANA) and N-glycolylneuraminic acid (NGNA) was developed by using high-performance capillary electrophoresis (HPCE) with UV detection at 195 nm. NANA and NGNA were separated directly and analyzed without pre- or postcolumn derivation. The detection limit of NANA is 9.6 x 10(-6) mol L-1 and for mass 3.879 x 10(-14) mol (39 fmol). This method was applied for the determination of NANA in 30 normal human and 72 cancer patients. The results demonstrated that NANA in the sera of cancer patients increased significantly as compared with the normal human (P < 0.001). The new method is simple and sensitive, and is suitable for basic research and clinical application to malignant tumors.

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Zeolite membranes with high permeance and separation factors are highly desirable for practical applications. Although, in the past, very good separation factors have been obtained, it has proved difficult to achieve a high permeance. Ken a comparative study of microwave versus conventional heating in the hydrothermal synthesis of NaA zeolite membranes is made. It is demonstrated that membranes prepared by microwave heating have not only a higher permeance but also a considerably shorter synthesis time. These observations are rationalized by examining the mechanism of membrane formation.