The exact calculation of point kinetic parameters is very important in nuclear reactor safety assessment, and most sophisticated safety codes such as RELAP5, PARCS,DYN3D, and PARET are using these parameters in their ...The exact calculation of point kinetic parameters is very important in nuclear reactor safety assessment, and most sophisticated safety codes such as RELAP5, PARCS,DYN3D, and PARET are using these parameters in their dynamic models. These parameters include effective delayed neutron fractions as well as mean generation time.These parameters are adjoint-weighted, and adjoint flux is employed as a weighting function in their evaluation.Adjoint flux calculation is an easy task for most of deterministic codes, but its evaluation is cumbersome for Monte Carlo codes. However, in recent years, some sophisticated techniques have been proposed for Monte Carlo-based point kinetic parameters calculation without any need of adjoint flux. The most straightforward scheme is known as the ‘‘prompt method'' and has been used widely in literature. The main objective of this article is dedicated to point kinetic parameters calculation in Tehran research reactor(TRR) using deterministic as well as probabilistic techniques. WIMS-D5B and CITATION codes have been used in deterministic calculation of forward and adjoint fluxes in the TRR core. On the other hand, the MCNP Monte Carlo code has been employed in the ‘‘prompt method''scheme for effective delayed neutron fraction evaluation.Deterministic results have been cross-checked with probabilistic ones and validated with SAR and experimental data. In comparison with experimental results, the relativedifferences of deterministic as well as probabilistic methods are 7.6 and 3.2%, respectively. These quantities are10.7 and 6.4%, respectively, in comparison with SAR report.展开更多
This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village ho...This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village houses. The stratum structure control action of mining subsidence was used to design the mining and pillar width. To further raise resources recovery, we adopted the mutative scheme of mining and pillar width. Observation was carried out while mining. Research shows there is feasibility of the strip mining technology to protecting the village buildings of the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. Finally, subsidence parameters of strip mining were obtained. It is the basic data of the strip mining of the coal field at the north of the Yellow River.展开更多
针对线控转向(steering-by-wire,SBW)车辆路径跟踪的工况适应性问题,根据车辆在中低速和高速工况下的运动状态差异,提出了一种考虑车辆状态估计的横向分层控制策略。首先,为提供可靠的状态量,设计状态估计方法;随后,为提升工况适应性,...针对线控转向(steering-by-wire,SBW)车辆路径跟踪的工况适应性问题,根据车辆在中低速和高速工况下的运动状态差异,提出了一种考虑车辆状态估计的横向分层控制策略。首先,为提供可靠的状态量,设计状态估计方法;随后,为提升工况适应性,在上层设计低速DM-LQR控制器(Double model LQR controller)和高速模糊PID控制器,并在下层考虑线控转向系统的动力学特性;然后,使用模糊权重控制器进行控制方法的选择;最后,基于CarSim-Matlab/Simulink联合仿真平台对所设计的分层控制策略进行验证,仿真结果表明该控制策略在不同工况下都具有较高的控制精度。展开更多
盐体是具有良好气密性的地质构造,有利于油气储存,实现精细化盐体的解释极为必要。然而,不同于断层,盐体的特征较为复杂且形态差异大,常规方法易导致混淆和误判。此外,基于数据驱动的盐体识别模型在实际数据集上的泛化能力较差,因此目...盐体是具有良好气密性的地质构造,有利于油气储存,实现精细化盐体的解释极为必要。然而,不同于断层,盐体的特征较为复杂且形态差异大,常规方法易导致混淆和误判。此外,基于数据驱动的盐体识别模型在实际数据集上的泛化能力较差,因此目前在地震勘探中进行盐体的解释及可视化仍存在挑战。文章将盐体解释视为地震图像的语义分割问题,提出了基于迁移学习的上下文融合与混合注意力的智能盐体分割(Multi-path structure Mixed Attention and Transfer Optimized Net,MMTONet)方法。同时设计了一种基于盐体上下文特征融合模块,进而建立了改进注意力卷积混合的跳跃连接机制,以更好地弥补由下采样造成的信息损失,从而提高模型对盐体边界与高振幅噪声的像素级辨别能力。在此基础上,还设计了迁移学习的适配器微调策略,提升了模型在实际数据上的泛化能力。在地震数据集上的实验结果表明,MMTONet在提高分割精度和减少计算量、参数量方面均优于主流的语义分割方法。展开更多
文摘The exact calculation of point kinetic parameters is very important in nuclear reactor safety assessment, and most sophisticated safety codes such as RELAP5, PARCS,DYN3D, and PARET are using these parameters in their dynamic models. These parameters include effective delayed neutron fractions as well as mean generation time.These parameters are adjoint-weighted, and adjoint flux is employed as a weighting function in their evaluation.Adjoint flux calculation is an easy task for most of deterministic codes, but its evaluation is cumbersome for Monte Carlo codes. However, in recent years, some sophisticated techniques have been proposed for Monte Carlo-based point kinetic parameters calculation without any need of adjoint flux. The most straightforward scheme is known as the ‘‘prompt method'' and has been used widely in literature. The main objective of this article is dedicated to point kinetic parameters calculation in Tehran research reactor(TRR) using deterministic as well as probabilistic techniques. WIMS-D5B and CITATION codes have been used in deterministic calculation of forward and adjoint fluxes in the TRR core. On the other hand, the MCNP Monte Carlo code has been employed in the ‘‘prompt method''scheme for effective delayed neutron fraction evaluation.Deterministic results have been cross-checked with probabilistic ones and validated with SAR and experimental data. In comparison with experimental results, the relativedifferences of deterministic as well as probabilistic methods are 7.6 and 3.2%, respectively. These quantities are10.7 and 6.4%, respectively, in comparison with SAR report.
文摘This paper focuses on the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. The strip mining technology was used to protect the village houses. The stratum structure control action of mining subsidence was used to design the mining and pillar width. To further raise resources recovery, we adopted the mutative scheme of mining and pillar width. Observation was carried out while mining. Research shows there is feasibility of the strip mining technology to protecting the village buildings of the village coal pillar under huge thick loose bed and thin bedrock over high prelatic water level at the north of the Yellow River. Finally, subsidence parameters of strip mining were obtained. It is the basic data of the strip mining of the coal field at the north of the Yellow River.
文摘针对线控转向(steering-by-wire,SBW)车辆路径跟踪的工况适应性问题,根据车辆在中低速和高速工况下的运动状态差异,提出了一种考虑车辆状态估计的横向分层控制策略。首先,为提供可靠的状态量,设计状态估计方法;随后,为提升工况适应性,在上层设计低速DM-LQR控制器(Double model LQR controller)和高速模糊PID控制器,并在下层考虑线控转向系统的动力学特性;然后,使用模糊权重控制器进行控制方法的选择;最后,基于CarSim-Matlab/Simulink联合仿真平台对所设计的分层控制策略进行验证,仿真结果表明该控制策略在不同工况下都具有较高的控制精度。
文摘盐体是具有良好气密性的地质构造,有利于油气储存,实现精细化盐体的解释极为必要。然而,不同于断层,盐体的特征较为复杂且形态差异大,常规方法易导致混淆和误判。此外,基于数据驱动的盐体识别模型在实际数据集上的泛化能力较差,因此目前在地震勘探中进行盐体的解释及可视化仍存在挑战。文章将盐体解释视为地震图像的语义分割问题,提出了基于迁移学习的上下文融合与混合注意力的智能盐体分割(Multi-path structure Mixed Attention and Transfer Optimized Net,MMTONet)方法。同时设计了一种基于盐体上下文特征融合模块,进而建立了改进注意力卷积混合的跳跃连接机制,以更好地弥补由下采样造成的信息损失,从而提高模型对盐体边界与高振幅噪声的像素级辨别能力。在此基础上,还设计了迁移学习的适配器微调策略,提升了模型在实际数据上的泛化能力。在地震数据集上的实验结果表明,MMTONet在提高分割精度和减少计算量、参数量方面均优于主流的语义分割方法。
