In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried ou...In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried out using a numerical simulation package(Fluent) based on gas-solid coupling dispersed multiphase flow model and field measurement to research different technology modes, dust distribution law at different intervals where shearers work in opposite directions on the lower 9303 face, No. 2 Jining Mine,Yankuang Coal Mining Co. Results show that the concentration of dust 3–6 m away from the shearers working in the same directions was large, while the impact area of respirable dust near the shearer increased significantly to 5–6 m with the distance between two shearers working in opposite directions.The concentration of dust on a double-shearer face was considerably higher than that of a face with one shear under the combined effect of wind speed on the face and disturbed wind around the shearer, while the dust concentration near the shearer on the return side was considerably higher than that on the inlet side. The concentration of dust on a double-shearer face along the airflow declined slowly so that dust was hard to control. Simulation results confirmed the results of field measurement, which could provide reference for dust prevention design.展开更多
As a constant and active factor affecting population migration, marriage has long been neglected. This paper brings to light of the social significance of marriage migration and makes an inquiry into its characteristi...As a constant and active factor affecting population migration, marriage has long been neglected. This paper brings to light of the social significance of marriage migration and makes an inquiry into its characteristics, patterns and mechanism. It is thought the marriage plays an important role in hastening population migration. While compared with other forms of population migration, marriage migration is distinctive, showing its own characteristics, such as irreversibility in direction, shorter distance, age long continuity, regional dispersal, gentler fluctuation in number, sexual imbalance, and multiple factors at work. Although the manifestation of marriage migration is complicated, its patterns are clear, that is: pattern 1, women to men’s habitation; pattern 2, men to women’s habitation; and pattern 3, men and women to a third place. It is thought that both the characters and the patterns of marriage migration are determined by its mechanism, because marriage migration is not only a kind of biological action but also a kind of social action, the former of which determines whether it happens, while the latter of which determines how it does. The difference of men’s and women’s social status, that of cities and country, and that of developed and backward areas may result in abnormality of marriage migration, while the socio biological feedback of sexual imbalance and regional environmental deterioration can give rise to some self adjusting mechanism. In the end of the paper, based on a sample analysis, it concludes four tendencies towards marriage migration in China: (1) pair migration is emerging; (2) the changing trend of urban and rural regional relationship of marriage is contrary; (3) urban “island effect” in marriage is weakening; and (4) the potential energy between developed and less developed areas is still strong.展开更多
以提高瓦斯抽采效果为目标,某矿Ⅲ4423工作面为研究对象,采用理论分析、数值模拟、现场试验等研究方法,研究了顶板高位钻孔条件下瓦斯抽采的主要技术参数,数值模拟出高位钻孔抽采瓦斯前采空区的瓦斯分布情况与运移规律,以及负压分别为8...以提高瓦斯抽采效果为目标,某矿Ⅲ4423工作面为研究对象,采用理论分析、数值模拟、现场试验等研究方法,研究了顶板高位钻孔条件下瓦斯抽采的主要技术参数,数值模拟出高位钻孔抽采瓦斯前采空区的瓦斯分布情况与运移规律,以及负压分别为8、10 k Pa时的高位钻孔瓦斯抽采效果。依据瓦斯流动"O"型圈理论与FLUENT数值模拟分析,优化设计高位钻孔抽采瓦斯工艺参数并进行现场试验。结果表明:当高位钻孔抽采负压为8 k Pa、终孔位置调整到采空区裂隙带回风巷侧15~35 m范围内时,高位钻孔抽采瓦斯效果最佳,采空区内瓦斯最高浓度明显降低,单个钻场最大抽采瓦斯量为19 821.74 m^3,钻孔瓦斯浓度稳定在20%~30%之间,最大值达到50%,实现了工作面有效治理瓦斯和安全生产的目标。展开更多
基金the National Natural Science Foundation of China (No.51404249)the Basic Research Program of Jiangsu Province (No.BK20140201)the Priority Academic Program Development of Jiangsu Higher Education Institutions for financial support provided during this research
文摘In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried out using a numerical simulation package(Fluent) based on gas-solid coupling dispersed multiphase flow model and field measurement to research different technology modes, dust distribution law at different intervals where shearers work in opposite directions on the lower 9303 face, No. 2 Jining Mine,Yankuang Coal Mining Co. Results show that the concentration of dust 3–6 m away from the shearers working in the same directions was large, while the impact area of respirable dust near the shearer increased significantly to 5–6 m with the distance between two shearers working in opposite directions.The concentration of dust on a double-shearer face was considerably higher than that of a face with one shear under the combined effect of wind speed on the face and disturbed wind around the shearer, while the dust concentration near the shearer on the return side was considerably higher than that on the inlet side. The concentration of dust on a double-shearer face along the airflow declined slowly so that dust was hard to control. Simulation results confirmed the results of field measurement, which could provide reference for dust prevention design.
文摘As a constant and active factor affecting population migration, marriage has long been neglected. This paper brings to light of the social significance of marriage migration and makes an inquiry into its characteristics, patterns and mechanism. It is thought the marriage plays an important role in hastening population migration. While compared with other forms of population migration, marriage migration is distinctive, showing its own characteristics, such as irreversibility in direction, shorter distance, age long continuity, regional dispersal, gentler fluctuation in number, sexual imbalance, and multiple factors at work. Although the manifestation of marriage migration is complicated, its patterns are clear, that is: pattern 1, women to men’s habitation; pattern 2, men to women’s habitation; and pattern 3, men and women to a third place. It is thought that both the characters and the patterns of marriage migration are determined by its mechanism, because marriage migration is not only a kind of biological action but also a kind of social action, the former of which determines whether it happens, while the latter of which determines how it does. The difference of men’s and women’s social status, that of cities and country, and that of developed and backward areas may result in abnormality of marriage migration, while the socio biological feedback of sexual imbalance and regional environmental deterioration can give rise to some self adjusting mechanism. In the end of the paper, based on a sample analysis, it concludes four tendencies towards marriage migration in China: (1) pair migration is emerging; (2) the changing trend of urban and rural regional relationship of marriage is contrary; (3) urban “island effect” in marriage is weakening; and (4) the potential energy between developed and less developed areas is still strong.
文摘以提高瓦斯抽采效果为目标,某矿Ⅲ4423工作面为研究对象,采用理论分析、数值模拟、现场试验等研究方法,研究了顶板高位钻孔条件下瓦斯抽采的主要技术参数,数值模拟出高位钻孔抽采瓦斯前采空区的瓦斯分布情况与运移规律,以及负压分别为8、10 k Pa时的高位钻孔瓦斯抽采效果。依据瓦斯流动"O"型圈理论与FLUENT数值模拟分析,优化设计高位钻孔抽采瓦斯工艺参数并进行现场试验。结果表明:当高位钻孔抽采负压为8 k Pa、终孔位置调整到采空区裂隙带回风巷侧15~35 m范围内时,高位钻孔抽采瓦斯效果最佳,采空区内瓦斯最高浓度明显降低,单个钻场最大抽采瓦斯量为19 821.74 m^3,钻孔瓦斯浓度稳定在20%~30%之间,最大值达到50%,实现了工作面有效治理瓦斯和安全生产的目标。
