Dr Shaffer draws a parallel with a classic virus-infection curve: high at the beginning as those most susceptible fall ill, but gradually tailing off as people adapt.
The paper deduces the calculation formula of parallel sidelines of spiral curve, and proves two characters of parallels sidelines. It can be applied to instruct actual setting-out work.
推导了缓和曲线的平行边线弧长计算公式，证明了平行边线的两个性质，对实际线路测设工作有指导意义。
3
Mainfactors are as follows: standard solution, regressive curve, parallel experiment of sample, diacetyl monoxide's reagent colorimetric method, spectrophotometer, sampling, etc.