sign

So analysing the causes,signs and controling of roof fall is the key of mining in coal mine.

冒顶是煤矿生产中常见的事故,因此认识冒顶的原因及预兆,控制好冒顶是煤矿安全生产的重要保

We apply the concept and method developed in part I of this paper to determine the presage day and the onset day of summer monsoon in South China Sea region for every particular year.

用该指标定义的南海夏季风建立的预兆日期与用传统天气气候学方法确定的南海夏季风的来临日期,在绝大多数具体年份两者均很接近,故可作南海夏季风建立的先兆指标。