定容式气体微流量标准装置的不确定度分析

UNCERTAINTY ANALYSIS ON CONSTANT VOLUME FLOW STANDARD

定容式气体微流量标准装置采用定容法工作原理 ,用于校准热容式质量流量计 ,测量范围为1×10 -3～10Pa·m3·s -1 ,不确定度(1σ)小于1.20 %。

The constant volume flow standard adopts the constant volume method. The standard can be used to calibrate thermal mass flow meters. The range ofthe standard is from 1×10 3 to 10 Pa·m3·s-1 with uncertainty less than 1.2 %. The uncertainty (1 σ) of the standard is analyzed.Key words: vacuum;measurement standard;flow;uncertaintyontrol$$$$ FU Ke ming (Department of Physics, Yantai University, Yantai 264635, China)Abstract: In this paper, the deadline scheduling with interrupt points policy is proposed, underwhich a necessary and sufficient condition of the schedulability of n real time transport connections is given for statistical guarantees in transport communication services. Based on the necessary and sufficient condition, the connection control algorithms for statistical guarantees of QoS is given. The buffer space needed for each real time transport connection is also calculated.These results could be applied to other fields as well, such as real time operating systems.