The second, the flame shape and color were determined by the concentration gradient of the place near the igniting position.
其次，火焰的形状和火焰的颜色是由点火位置附近的浓度梯度决定的。
2
For example, it may be done on the basis of business units, or on the basis of the type of product, length of period, the degree of concentration in a position, or differences in risk factors.
例如按业务单位是一种方式，其它如按产品种类，期间长短，部位集中度，不同风险因子等均是可行之方法。
3
By arranging the position of buildings, the area of high pollutant concentration can be reduced efficiently.