挥发速度的英文：
volatilization rate

volatilization是什么意思：
n. 挥发,发散

Petrol is a volatile substance.
汽油是挥发性物质。

He has a volatile temper.
他脾气反复无常。

It is dispersed either by thermal volatilization or as a dust.
它用加热蒸发或粉尘的方式散发。

The poet is highly nervous and volatile in temperament.
诗人生性神经过敏，喜怒无常。

Volatility is the order of the day in the stock market.
上下浮动是股票市场整天的特点。

rate是什么意思：
n. 比率，速率；费用
v. 评估；认为；划分等级；值得

cumulative rating
累积收听率

These bonds have an AAA rating.
这些债券的信用度是3A级的。

To rate too low;underestimate.
低估对…估价太低；低估

A Lump Sum Rate of ...
费用合计…

To reduce in rank or rating;demote.
使降级降低级别或降级；使人降级