The purpose of this study is to develop a system that enables location finding of a small sound. The location finding of a small sound has some difficulties such as high computational costs or disturbances from the am...The purpose of this study is to develop a system that enables location finding of a small sound. The location finding of a small sound has some difficulties such as high computational costs or disturbances from the ambient noises and reflected waves. The proposed system is composed of a biologically-inspired system which uses a hearing mechanism based on the human ear and a mechanism for perceiving weak signals that uses stochastic resonance. The location finding mechanism in the proposed system is based on the time-lag detecting architecture. On the other hand, the stochastic resonance mechanism can pick up the small sound source in the ambient noises. Using this proposed system, we implemented the location finding of small sounds through numerical simulations and hardware experiments. Good results were obtained for the small sound source location finding.展开更多
In the eastern edge of the Ordos Basin,the coalbed methane(CBM)development has not made substantial progress in the past20 years,and the origin of gas can be used to guide the CBM block-selecting and development.Based...In the eastern edge of the Ordos Basin,the coalbed methane(CBM)development has not made substantial progress in the past20 years,and the origin of gas can be used to guide the CBM block-selecting and development.Based on the 37 sets of carbon isotope data,the origin of the gas was determined and the origin mechanism was studied in this work.The 13CPDB of methane ranges from 70.5‰to 36.19‰in the eastern edge in the Ordos Basin and the value becomes heavier from the north to the south.The secondary biogenic gas and the thermogenic gas are mixed in the shallow area and the thermogenic gas occurs in the medium and deep levels.The phenomenon is controlled mainly by the distribution of coal rank and hydrodynamics.Firstly,based on the relationship between China coal rank and methane 13CPDB,the medium rank coal is dominant in the eastern edge of the Ordos Basin,and the mixture of the secondary biogenic gas and the thermogenic gas is formed in the coal of vitrinite reflectant ratio(Rmax)between 0.5%and 2.0%if there is appropriate hydrodynamics;at the same time,because of the shallow burial depth,and the well-developed coal outcrop,meteoric water and other surface water carrying bacteria recharge the coal reservoir,metabolize the organic compounds at a relatively low temperature,and generate methane and carbon dioxide.Wherever the trapping mechanisms occur in the coal,such as Liulin and Hancheng,modern gas content should be high.展开更多
Based on the micro-fluorescence observation of polished sections of source rocks,two types of micro-layers with different wetting properties formed in thermal evolution,i.e.,oil-wetting and water-wetting micro-layers,...Based on the micro-fluorescence observation of polished sections of source rocks,two types of micro-layers with different wetting properties formed in thermal evolution,i.e.,oil-wetting and water-wetting micro-layers,are distinguished.The wetting property is found closely related to the abundance of organic matter and its occurrences with inorganic minerals.The alternating distribution and intercrossing of two types of micro-layers formed many separated spaces with different wettabilities.The strong capillary forces in these separated spaces with different wettibilities obstruct the cross flows of pore fluids and result in nearly independent and closed fluid systems.As a consequence,these spatially superposed spaces in source rocks bear the overburden pressure and then abnormally high pressures have developed in the whole source rock unit.Therefore,the abundance and occurrences of organic matter are the main inner factors influencing the formation of abnormally high pressures,whereas the formation,distribution and development of micro-layers with different wettabilities during the evolution of source rock determine the intensity and spatial distribution of abnormally high pressures.展开更多
文摘The purpose of this study is to develop a system that enables location finding of a small sound. The location finding of a small sound has some difficulties such as high computational costs or disturbances from the ambient noises and reflected waves. The proposed system is composed of a biologically-inspired system which uses a hearing mechanism based on the human ear and a mechanism for perceiving weak signals that uses stochastic resonance. The location finding mechanism in the proposed system is based on the time-lag detecting architecture. On the other hand, the stochastic resonance mechanism can pick up the small sound source in the ambient noises. Using this proposed system, we implemented the location finding of small sounds through numerical simulations and hardware experiments. Good results were obtained for the small sound source location finding.
基金supported by the National Basic Research Program of China(Grant No.2009CB219602)
文摘In the eastern edge of the Ordos Basin,the coalbed methane(CBM)development has not made substantial progress in the past20 years,and the origin of gas can be used to guide the CBM block-selecting and development.Based on the 37 sets of carbon isotope data,the origin of the gas was determined and the origin mechanism was studied in this work.The 13CPDB of methane ranges from 70.5‰to 36.19‰in the eastern edge in the Ordos Basin and the value becomes heavier from the north to the south.The secondary biogenic gas and the thermogenic gas are mixed in the shallow area and the thermogenic gas occurs in the medium and deep levels.The phenomenon is controlled mainly by the distribution of coal rank and hydrodynamics.Firstly,based on the relationship between China coal rank and methane 13CPDB,the medium rank coal is dominant in the eastern edge of the Ordos Basin,and the mixture of the secondary biogenic gas and the thermogenic gas is formed in the coal of vitrinite reflectant ratio(Rmax)between 0.5%and 2.0%if there is appropriate hydrodynamics;at the same time,because of the shallow burial depth,and the well-developed coal outcrop,meteoric water and other surface water carrying bacteria recharge the coal reservoir,metabolize the organic compounds at a relatively low temperature,and generate methane and carbon dioxide.Wherever the trapping mechanisms occur in the coal,such as Liulin and Hancheng,modern gas content should be high.
文摘Based on the micro-fluorescence observation of polished sections of source rocks,two types of micro-layers with different wetting properties formed in thermal evolution,i.e.,oil-wetting and water-wetting micro-layers,are distinguished.The wetting property is found closely related to the abundance of organic matter and its occurrences with inorganic minerals.The alternating distribution and intercrossing of two types of micro-layers formed many separated spaces with different wettabilities.The strong capillary forces in these separated spaces with different wettibilities obstruct the cross flows of pore fluids and result in nearly independent and closed fluid systems.As a consequence,these spatially superposed spaces in source rocks bear the overburden pressure and then abnormally high pressures have developed in the whole source rock unit.Therefore,the abundance and occurrences of organic matter are the main inner factors influencing the formation of abnormally high pressures,whereas the formation,distribution and development of micro-layers with different wettabilities during the evolution of source rock determine the intensity and spatial distribution of abnormally high pressures.
