放射性碘是核环境保护的重要监测内容。目前,碘监测仪均采用圆柱形活性炭取样盒,由均匀分布的标准体源进行效率标定,很难模拟实际测量中碘在活性炭盒中的分布情况,因此无法准确标定其探测效率。为了检验碘监测仪探测效率的准确性,利用...放射性碘是核环境保护的重要监测内容。目前,碘监测仪均采用圆柱形活性炭取样盒,由均匀分布的标准体源进行效率标定,很难模拟实际测量中碘在活性炭盒中的分布情况,因此无法准确标定其探测效率。为了检验碘监测仪探测效率的准确性,利用蒙特卡罗软件MCNP(Monte Carlo N Particle Transport Code),模拟计算了EIM型碘监测仪对碘在活性炭取样盒内呈不同分布情况下的探测效率,并进行验证。同时建立的碘监测仪探测效率的蒙特卡罗模型,为改进仪器设计,提高探测效率的准确度提供参考。结果表明:对于与探测器同轴的井型活性炭采样盒,使用均匀分布体源标定碘监测仪的探测效率准确度较高。展开更多
This study presents the effect of non-uniform heat source on the magneto-hydrodynamic flow of nanofluid across an expanding plate with consideration of the homogeneous-heterogeneous reactions and thermal radiation eff...This study presents the effect of non-uniform heat source on the magneto-hydrodynamic flow of nanofluid across an expanding plate with consideration of the homogeneous-heterogeneous reactions and thermal radiation effects.A nanofluid’s dynamic viscosity and effective thermal conductivity are specified with Corcione correlation.According to this correlation,the thermal conductivity is carried out by the Brownian motion.Similarity transformations reduce the governing equations concerned with energy,momentum,and concentration of nanofluid and then numerically solved.The influences of the effective parameters,e.g.,the internal heat source parameters,the volume fraction of nanofluid,the radiation parameter,the homogeneous reaction parameter,the magnetic parameter,the heterogeneous parameter and the Schmidt number are studied on the heat and flow transfer features.Further,regarding the effective parameters of the present work,the correlation for the Nusselt number has been developed.The outcomes illustrate that with the raising of the heterogeneous parameter and the homogeneous reaction parameter,the concentration profile diminishes.In addition,the outcomes point to a reverse relationship between the Nusselt number and the internal heat source parameters.展开更多
The microscopic approach is developed for obtaining of the free energy of a superconductor based on direct calculation of the vacuum amplitude.The free energy functional of the spatially inhomogeneous superconductor i...The microscopic approach is developed for obtaining of the free energy of a superconductor based on direct calculation of the vacuum amplitude.The free energy functional of the spatially inhomogeneous superconductor in a magnetic field is obtained with help of the developed approach.The obtained functional is generalization of GinzburgLandau functionals for any temperature,for arbitrary spatial variations of the order parameter and for the nonlocality of a magnetic response and the order parameter.Moreover,the nonlocality of the magnetic response is the consequence of order parameter's nonlocality.The extremals of this functional are considered in the explicit form in the low-and high-temperature limit at the condition of slowness of spatial variations of the order parameter.展开更多
文摘放射性碘是核环境保护的重要监测内容。目前,碘监测仪均采用圆柱形活性炭取样盒,由均匀分布的标准体源进行效率标定,很难模拟实际测量中碘在活性炭盒中的分布情况,因此无法准确标定其探测效率。为了检验碘监测仪探测效率的准确性,利用蒙特卡罗软件MCNP(Monte Carlo N Particle Transport Code),模拟计算了EIM型碘监测仪对碘在活性炭取样盒内呈不同分布情况下的探测效率,并进行验证。同时建立的碘监测仪探测效率的蒙特卡罗模型,为改进仪器设计,提高探测效率的准确度提供参考。结果表明:对于与探测器同轴的井型活性炭采样盒,使用均匀分布体源标定碘监测仪的探测效率准确度较高。
文摘This study presents the effect of non-uniform heat source on the magneto-hydrodynamic flow of nanofluid across an expanding plate with consideration of the homogeneous-heterogeneous reactions and thermal radiation effects.A nanofluid’s dynamic viscosity and effective thermal conductivity are specified with Corcione correlation.According to this correlation,the thermal conductivity is carried out by the Brownian motion.Similarity transformations reduce the governing equations concerned with energy,momentum,and concentration of nanofluid and then numerically solved.The influences of the effective parameters,e.g.,the internal heat source parameters,the volume fraction of nanofluid,the radiation parameter,the homogeneous reaction parameter,the magnetic parameter,the heterogeneous parameter and the Schmidt number are studied on the heat and flow transfer features.Further,regarding the effective parameters of the present work,the correlation for the Nusselt number has been developed.The outcomes illustrate that with the raising of the heterogeneous parameter and the homogeneous reaction parameter,the concentration profile diminishes.In addition,the outcomes point to a reverse relationship between the Nusselt number and the internal heat source parameters.
文摘The microscopic approach is developed for obtaining of the free energy of a superconductor based on direct calculation of the vacuum amplitude.The free energy functional of the spatially inhomogeneous superconductor in a magnetic field is obtained with help of the developed approach.The obtained functional is generalization of GinzburgLandau functionals for any temperature,for arbitrary spatial variations of the order parameter and for the nonlocality of a magnetic response and the order parameter.Moreover,the nonlocality of the magnetic response is the consequence of order parameter's nonlocality.The extremals of this functional are considered in the explicit form in the low-and high-temperature limit at the condition of slowness of spatial variations of the order parameter.
