密封器件氦质谱细检漏技术所对应的气流状态为分子流.目前好的粗检法可以检出100Pa·cm3/s或更小的漏率.为了与粗检方法相衔接，我们取密封器件氦质谱细检漏的等效标准漏率上限为1.4Pa·cm3/s.本文分析了这一上限的合理性.本文将漏孔简化为长径比相当大的圆管，按照Dushman的近似理论，将漏孔看作是由一个孔眼与一根长管串联组成，利用传统的分子流、黏滞流流导公式，对21世纪多篇文献报导的微型管
中国国家军用标准GJB128/360/548、相应的美国军用标准、相近的中国国家标准和国际电工委员会标准中的密封性氦质谱细检漏方法,所采用的氦气测量漏率公式,普遍以等效(空气)标准漏率L为主要变量,并且以Lmax为基本判据,个别标准以空气交换(漏泄)时间常数θ为基本判据,但仍以L为主要变量。在气体交换漏泄的分子流范畴,L是虚拟的、而不是真实的物理量,而且以Lmax为基本判据,常使不同内腔体积时可靠
本论文设计了在KT-ST装置真空室小截面中心的金属内置导体环及相关的配套系统，实现了稳态等离子体放电的成功运行。这些工作让KT-ST装置具备了一种新的工程实验的基础条件，使得其可以长时间保持一个具有类托卡马克磁面结构的等离子体环境。装置的适应性和可实验研究范围得到了有效的扩展，有利于进行托卡马克边界等离子体物理可比的实验。本论文模拟了KT-ST装置的磁力线位形，并测量了真空磁场的空间分布，发现实际
Uranium exploration activities are ongoing in various parts of Tanzania and uranium mining and milling may start in the near future.Manyoni district located in Singida central Tanzania is one of the a
Automatic and continuous monitoring of radon concentration has become urgent demand in many environmental monitoring.However,the present instrument for continuous Radon measurement still has some issu
The Changjiang River is the third longest river in the world,the longest river in China.It has a drainage area of about l.8 million square kilometers.Because of the fallout of nuclear tests and the di
In Sweden the production of Naturally Occurring Radioactive Material,NORM,is relatively small.Activity concentrations above 1 Bq/g in NORM can mainly be found in used water treatment filters,scale in
The Fen complex,including the Sove mines,is located approximately 120 km southwest of Oslo,Norway.Up t0 1927 the Sove mines were used for the mining of iron ore and in 1920 the carbonatite mineral Sov
The huge amount of world-wide naturally occurring radioactive material (NORM) production shows a high level of complexity for monitoring purposes because of the high variability of radioactivity enric
Mining has been identified as one of the potential sources of exposure to naturally occurring radioactive materials (NORM).However,mining companies are not being regulated for NORM in Sierra Leone unt