环境辐射监测仪表作为微弱放射性监测计量器具,它的量值溯源是一个急需解决的问题。由于环境辐射剂量率低且电离信号微弱,故通常采用大体积电离室或者充压电离室进行测量。依托60~250 k V X射线空气比释动能基准电离室,在完成重过滤窄谱...环境辐射监测仪表作为微弱放射性监测计量器具,它的量值溯源是一个急需解决的问题。由于环境辐射剂量率低且电离信号微弱,故通常采用大体积电离室或者充压电离室进行测量。依托60~250 k V X射线空气比释动能基准电离室,在完成重过滤窄谱X射线辐射质空气比释动能绝对测量的基础上,通过逐级替代法完成大体积环境辐射监测仪器的校准。测量结果不确定度为5.6%(k=2),实现环境水平X射线空气比释动能测量量值溯源,为国内环境辐射监测仪器在低剂量率水平的性能评价提供计量保障。展开更多
使用标准放射源对用于X射线测量的SDD探测器进行能量刻度。对北京同步辐射装置的4W1A实验站单色光模式下6~20 ke V的X射线能谱进行测量。测量结果表明,所测能量值与理论值偏差在3%之内,且除15 ke V外偏差随能量增加而增加。能量较低的单...使用标准放射源对用于X射线测量的SDD探测器进行能量刻度。对北京同步辐射装置的4W1A实验站单色光模式下6~20 ke V的X射线能谱进行测量。测量结果表明,所测能量值与理论值偏差在3%之内,且除15 ke V外偏差随能量增加而增加。能量较低的单能X射线多次谐波现象较为严重,经过微调单色器角度,多次谐波受到抑制。并研究了本测量方法的测量精度,不同能量点精度偏差为3.1‰~1.75%。为高注量率同步辐射空气比释动能的绝对测量以及同步辐射光源的利用提供参考。展开更多
A genuinely three-dimensional spacetime conservation element and solution element(CE/SE)scheme is built as simple,consistent and straightforward extensions of an improved high resolution 2D CE/SE scheme.It is applied ...A genuinely three-dimensional spacetime conservation element and solution element(CE/SE)scheme is built as simple,consistent and straightforward extensions of an improved high resolution 2D CE/SE scheme.It is applied to examine the mechanism of three-dimensional detonation process in rectangular ducts.The simulations clearly show detailed three-dimensional detonation modes,namely a rectangular mode and a diagonal mode.Furthermore,the formation of unreacted pockets with high density and low temperature behind the detonation is observed for the two modes.展开更多
We extend the conservation-element and solution-element method to simulate a two-phase detonation model in porous media.The accuracy of the method is validated by calculating an inert compaction problem.The main chara...We extend the conservation-element and solution-element method to simulate a two-phase detonation model in porous media.The accuracy of the method is validated by calculating an inert compaction problem.The main characteristics of piston-driven detonation phenomena,including the compaction wave,the onset of combustion,and the transition to detonation,could be predicted successfully.展开更多
文摘环境辐射监测仪表作为微弱放射性监测计量器具,它的量值溯源是一个急需解决的问题。由于环境辐射剂量率低且电离信号微弱,故通常采用大体积电离室或者充压电离室进行测量。依托60~250 k V X射线空气比释动能基准电离室,在完成重过滤窄谱X射线辐射质空气比释动能绝对测量的基础上,通过逐级替代法完成大体积环境辐射监测仪器的校准。测量结果不确定度为5.6%(k=2),实现环境水平X射线空气比释动能测量量值溯源,为国内环境辐射监测仪器在低剂量率水平的性能评价提供计量保障。
文摘使用标准放射源对用于X射线测量的SDD探测器进行能量刻度。对北京同步辐射装置的4W1A实验站单色光模式下6~20 ke V的X射线能谱进行测量。测量结果表明,所测能量值与理论值偏差在3%之内,且除15 ke V外偏差随能量增加而增加。能量较低的单能X射线多次谐波现象较为严重,经过微调单色器角度,多次谐波受到抑制。并研究了本测量方法的测量精度,不同能量点精度偏差为3.1‰~1.75%。为高注量率同步辐射空气比释动能的绝对测量以及同步辐射光源的利用提供参考。
基金Supported by the National Natural Science Foundation of China under Grant Nos 10732010 and 10972010.
文摘A genuinely three-dimensional spacetime conservation element and solution element(CE/SE)scheme is built as simple,consistent and straightforward extensions of an improved high resolution 2D CE/SE scheme.It is applied to examine the mechanism of three-dimensional detonation process in rectangular ducts.The simulations clearly show detailed three-dimensional detonation modes,namely a rectangular mode and a diagonal mode.Furthermore,the formation of unreacted pockets with high density and low temperature behind the detonation is observed for the two modes.
文摘We extend the conservation-element and solution-element method to simulate a two-phase detonation model in porous media.The accuracy of the method is validated by calculating an inert compaction problem.The main characteristics of piston-driven detonation phenomena,including the compaction wave,the onset of combustion,and the transition to detonation,could be predicted successfully.
