A serics of simulating experiments on the mechanism of formation of banded ironsilica formations have been made using a suite of self-designed glasswares to model the hypergene circulation of surface water.The simulat...A serics of simulating experiments on the mechanism of formation of banded ironsilica formations have been made using a suite of self-designed glasswares to model the hypergene circulation of surface water.The simulating process involved two stages;In the first stage weathering-leaching of basalts by strongly acidic meteoric water formed in the volcanic period of early Proeambrian,resulting in amorphous silica precipitates and strongly acidic ore solutions(pH,1.25),and in the second stage weathering-leaching of basalts by rainwater satupated with CO2 gas free fromcontamination of volcanie gases in the intermission of volcanic activity.Under such conditions the pH value of the seawater would increase.When the pH value rose to 1.25-3.00,ferric hydroxide and amorphous silica would be alternatively precipitated due to periodic heating of the upper solutions and continueous addition of pH-high basalt leaching solutions.This is a possible explanation for the mechanism of formation of banded iron-silica formations.展开更多
A conduction channel model is proposed to explain the high conductivity property of nc-Si: H. Detailed energy band diagram is developed based on the analysis and calculation, and the conductivity of the nc-Si: H was t...A conduction channel model is proposed to explain the high conductivity property of nc-Si: H. Detailed energy band diagram is developed based on the analysis and calculation, and the conductivity of the nc-Si: H was then analysed on the basis of energy band theory. It is assumed that the conductivity of the nc-Si: H stems from two parts: the conductance of the interface, where the transport mechanism is identified as a thermal-assisted tunnelling process, and the conductance along the channel around the grain, which mainly determined the high conductivity of the nc -Si: H. The conductivity of nc - Si: H is calculated and compared with the experiment data. The theory is in agreement with the experiment.展开更多
文摘A serics of simulating experiments on the mechanism of formation of banded ironsilica formations have been made using a suite of self-designed glasswares to model the hypergene circulation of surface water.The simulating process involved two stages;In the first stage weathering-leaching of basalts by strongly acidic meteoric water formed in the volcanic period of early Proeambrian,resulting in amorphous silica precipitates and strongly acidic ore solutions(pH,1.25),and in the second stage weathering-leaching of basalts by rainwater satupated with CO2 gas free fromcontamination of volcanie gases in the intermission of volcanic activity.Under such conditions the pH value of the seawater would increase.When the pH value rose to 1.25-3.00,ferric hydroxide and amorphous silica would be alternatively precipitated due to periodic heating of the upper solutions and continueous addition of pH-high basalt leaching solutions.This is a possible explanation for the mechanism of formation of banded iron-silica formations.
基金he Natural Science Foundation of Hubei Province of China!96J026
文摘A conduction channel model is proposed to explain the high conductivity property of nc-Si: H. Detailed energy band diagram is developed based on the analysis and calculation, and the conductivity of the nc-Si: H was then analysed on the basis of energy band theory. It is assumed that the conductivity of the nc-Si: H stems from two parts: the conductance of the interface, where the transport mechanism is identified as a thermal-assisted tunnelling process, and the conductance along the channel around the grain, which mainly determined the high conductivity of the nc -Si: H. The conductivity of nc - Si: H is calculated and compared with the experiment data. The theory is in agreement with the experiment.
