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听众
性别保密
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B.4.2 Cleanliness recovery performance 洁净度自净性能
Recovery performance is evaluated by using the 100:1 or 10:1 recovery time and/or the cleanliness
recovery rate. The 100:1 or 10:1 recovery time is defined as the time required for decreasing the initial
concentration by a factor of 100 times (or 10 times). The cleanliness recovery rate is defined as the rate
of change of particle concentration by time. It is possible to estimate both of these from the same particle
concentration decreasing curve. The measured concentration levels used should be taken from inside
the time range where the decreasing of particle concentration is described by a single exponential,
indicated by a straight line on a semi-log chart (concentrations on the ordinate by the logarithmic scale,
and the time values on the abscissa by the linear scale). Moreover, the test concentration should not be
so high that coincident loss occurs, or so low that counting uncertainty occurs.
自净性能采用 100:1 或 10:1 的自净时间和/或洁净级别恢复速度来评估。100:1 或 10:1 自净时间定义
为将初始浓度降低至 100 分之一(或 10 分之一)所需时间。洁净度恢复速度定义为粒子浓度随时间
变化的速度。用相同的粒子浓度衰减曲线能够预测出上述两项结果。测量应该在这样的时间范围内进
行,即粒子浓度用单一指数表述,该指数在半对数图(纵坐标上的浓度按对数刻度,横坐标上的时间
值按线性刻度)上以直线标出。另外,检测浓度不应过高而引起重合损耗,也不应过低而引起计数偏
差。 |
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