There was a calculation method for determining necessary lamps in a rectangled ultraviolet air washer, but it had a limiting condition.
国外已有矩形紫外线消毒器必要灯管数的计算公式，但有限定条件。
2
Presently, calculation method of a reinforced concrete isosceles trapezoid slab is experiential arithmetic with which the isosceles trapezoid slab is simplified into an equivalent rectangled slab.