This article deals with some properties of Galton-Watson branching processes in varying environments. A necessary and suffcient condition for relative recurrent state is presented, and a series of ratio limit properti...This article deals with some properties of Galton-Watson branching processes in varying environments. A necessary and suffcient condition for relative recurrent state is presented, and a series of ratio limit properties of the transition probabilities are showed.展开更多
In my ten-yeat experience of tenching English as major in college , I feel that students experience more difficulties in listening lessons than in other lessons. What, then, prevents students from achieving success in...In my ten-yeat experience of tenching English as major in college , I feel that students experience more difficulties in listening lessons than in other lessons. What, then, prevents students from achieving success in the listening class? I suggest that anxiety is one of the major factors, which interferes with students listening comprehension. And I would agree with writers such as Gardner and Horwitz et al. (1991)that anxiety may impede learner’s ability to perform successfully in all aspects of learning a foreign language. I feet it is particularly significant for listening.展开更多
为了解决采煤工作面冷损大,降温费用高,降温效果不理想的问题,提出了采煤工作面非均匀环境营建技术,研究了跟随工人旋转的跟踪型小型空冷器,提出了有效空冷空间和无效空冷空间的概念,确定了采煤工作面非均匀环境营建技术需冷量的计算公...为了解决采煤工作面冷损大,降温费用高,降温效果不理想的问题,提出了采煤工作面非均匀环境营建技术,研究了跟随工人旋转的跟踪型小型空冷器,提出了有效空冷空间和无效空冷空间的概念,确定了采煤工作面非均匀环境营建技术需冷量的计算公式。对某采煤工作面需冷量进行了计算,结果表明:传统降温方式需冷量为227.7 k W,采煤工作面非均匀环境营建技术需冷量为108 k W,1个采煤工作面每年可节省51.7万元降温费用。展开更多
基金supported by NNSF of China(6053408070571079)Open Fundation of SKLSE of Wuhan University (2008-07-03)
文摘This article deals with some properties of Galton-Watson branching processes in varying environments. A necessary and suffcient condition for relative recurrent state is presented, and a series of ratio limit properties of the transition probabilities are showed.
文摘In my ten-yeat experience of tenching English as major in college , I feel that students experience more difficulties in listening lessons than in other lessons. What, then, prevents students from achieving success in the listening class? I suggest that anxiety is one of the major factors, which interferes with students listening comprehension. And I would agree with writers such as Gardner and Horwitz et al. (1991)that anxiety may impede learner’s ability to perform successfully in all aspects of learning a foreign language. I feet it is particularly significant for listening.
文摘为了解决采煤工作面冷损大,降温费用高,降温效果不理想的问题,提出了采煤工作面非均匀环境营建技术,研究了跟随工人旋转的跟踪型小型空冷器,提出了有效空冷空间和无效空冷空间的概念,确定了采煤工作面非均匀环境营建技术需冷量的计算公式。对某采煤工作面需冷量进行了计算,结果表明:传统降温方式需冷量为227.7 k W,采煤工作面非均匀环境营建技术需冷量为108 k W,1个采煤工作面每年可节省51.7万元降温费用。