Part four is the hazard assessment of hillslope debris flow . because the hazard of hillslope debris flow mainly is pounding , the former formula ( hazard = magnitude x probability ) ca n ' t assess accurately the hazard of hillslope debris flow . applying the law of conservation of energy , we improved the formula as : hazard = energy x probability , and examined it on the basis of concrete example 鉴于山坡泥石流的危险性主要表现为冲击破坏，过去的泥石流评价公式，即“危险度=规模频率”已不能很好地评价山坡泥石流的危险性，因此我们运用能量守恒的观点，将泥石流的评价公式改进为“危险度=能量频率” ，并以具体实例加以检验。
It has a long history using a throttle device to measure the flow volume of fluid in pipe the method has formed normalization at home and abroad the principle is to make the flow bunch form the particial shrink at the place where the throttle part is located so as to produce a static pressure difference then measure and calculate the flow volume at the moment when the fluid is flowing through the throttle device by the static pressure measured this method is based on the law of conservation of energy and the equation of flow continuity 用节流装置测量管道中流体流量已历史悠久，在国内、国际上都已标准化，其原理是使流束在节流件处形成局部收缩，产生静压力差，通过测量静压力差来衡量流体流过节流装置时的流量大小，这种测量方法是以能量守恒定律和流动连续性方程为基础的。
