CCMS系统(Core Cooling and Monitoring System)是CPPR1000核电站重要的监测系统之一,当发生LBA失电故障时,其计算结果可能与实际情形产生误差。文章基于理论分析及仿真验证方法,对LBA失电故障后,CCMS的计算结果进行了分析研究。分析结...CCMS系统(Core Cooling and Monitoring System)是CPPR1000核电站重要的监测系统之一,当发生LBA失电故障时,其计算结果可能与实际情形产生误差。文章基于理论分析及仿真验证方法,对LBA失电故障后,CCMS的计算结果进行了分析研究。分析结果指出当发生LBA失电叠加LOCA事故时,CCMS计算出的堆芯水位低于实际水位,甚至低于THL阈值,导致操纵员判断失误,错误执行SOP规程。需要采取有效的防范措施及培训,防止出现错误判断堆芯水位或错误执行SOP规程。展开更多
The crop yields achieved through traditional plant breeding techniques appear to be nearing a plateau.Therefore,it is essential to accelerate advancements in photosynthesis,the fundamental process by which plants conv...The crop yields achieved through traditional plant breeding techniques appear to be nearing a plateau.Therefore,it is essential to accelerate advancements in photosynthesis,the fundamental process by which plants convert light energy into chemical energy,to further enhance crop yields.Research focused on improving photosynthesis holds significant promise for increasing sustainable agricultural productivity and addressing challenges related to global food security.This review examines the latest advancements and strategies aimed at boosting crop yields by enhancing photosynthetic efficiency.There has been a linear increase in yield over the years in historically released germplasm selected through traditional breeding methods,and this increase is accompanied by improved photosynthesis.We explore various aspects of the light reactions designed to enhance crop yield,including light harvest efficiency through smart canopy systems,expanding the absorbed light spectrum to include far-red light,optimizing non-photochemical quenching,and accelerating electron transport flux.At the same time,we investigate carbon reactions that can enhance crop yield,such as manipulating Rubisco activity,improving the Calvin-Benson-Bassham cycle,introducing CO_(2)concentrating mechanisms in C_(3)plants,and optimizing carbon allocation.These strategies could significantly impact crop yield enhancement and help bridge the yield gap.展开更多
Low porosity is very significant for cementitious composite materials(CCM)under freeze-thaw conditions.To reduce the porosity of CCM,we used wollastonite mineral fibers as a partial replacement for cement and aggregat...Low porosity is very significant for cementitious composite materials(CCM)under freeze-thaw conditions.To reduce the porosity of CCM,we used wollastonite mineral fibers as a partial replacement for cement and aggregate.The five combinations,in which 10%,32%,and 48%Wollastonite were added,were made for scanning using both scanning electron microscopy(SEM)and computed tomography scan technology(CT).Then,the 2D SEM pictures and the 3D pore distribution curves are obtained before and after the freezing and thawing processes,where the micro-pores in the CCM materials are shown.The fractal dimension is used to quantify the topography image in two dimensions,as well as the pore distribution in three dimensions.This method allows for the determination of both surface porosity and volume porosity,both of which show an increase in response to an escalation of freeze-thaw cycles.It is also found that the micro-damage in the concrete is of self-similarity,and in the context of the fractal dimension,the pore evolution can be quantitatively characterized across different sizes,ranging from local to global levels,before and after freezing and thawing.展开更多
文摘CCMS系统(Core Cooling and Monitoring System)是CPPR1000核电站重要的监测系统之一,当发生LBA失电故障时,其计算结果可能与实际情形产生误差。文章基于理论分析及仿真验证方法,对LBA失电故障后,CCMS的计算结果进行了分析研究。分析结果指出当发生LBA失电叠加LOCA事故时,CCMS计算出的堆芯水位低于实际水位,甚至低于THL阈值,导致操纵员判断失误,错误执行SOP规程。需要采取有效的防范措施及培训,防止出现错误判断堆芯水位或错误执行SOP规程。
基金funded by CAS Project for Young Scientists in Basic Research(YSBR-072-8)National Key Research and Development Program of China(2021YFF1000203 and 2022YFF1001704)。
文摘The crop yields achieved through traditional plant breeding techniques appear to be nearing a plateau.Therefore,it is essential to accelerate advancements in photosynthesis,the fundamental process by which plants convert light energy into chemical energy,to further enhance crop yields.Research focused on improving photosynthesis holds significant promise for increasing sustainable agricultural productivity and addressing challenges related to global food security.This review examines the latest advancements and strategies aimed at boosting crop yields by enhancing photosynthetic efficiency.There has been a linear increase in yield over the years in historically released germplasm selected through traditional breeding methods,and this increase is accompanied by improved photosynthesis.We explore various aspects of the light reactions designed to enhance crop yield,including light harvest efficiency through smart canopy systems,expanding the absorbed light spectrum to include far-red light,optimizing non-photochemical quenching,and accelerating electron transport flux.At the same time,we investigate carbon reactions that can enhance crop yield,such as manipulating Rubisco activity,improving the Calvin-Benson-Bassham cycle,introducing CO_(2)concentrating mechanisms in C_(3)plants,and optimizing carbon allocation.These strategies could significantly impact crop yield enhancement and help bridge the yield gap.
文摘Low porosity is very significant for cementitious composite materials(CCM)under freeze-thaw conditions.To reduce the porosity of CCM,we used wollastonite mineral fibers as a partial replacement for cement and aggregate.The five combinations,in which 10%,32%,and 48%Wollastonite were added,were made for scanning using both scanning electron microscopy(SEM)and computed tomography scan technology(CT).Then,the 2D SEM pictures and the 3D pore distribution curves are obtained before and after the freezing and thawing processes,where the micro-pores in the CCM materials are shown.The fractal dimension is used to quantify the topography image in two dimensions,as well as the pore distribution in three dimensions.This method allows for the determination of both surface porosity and volume porosity,both of which show an increase in response to an escalation of freeze-thaw cycles.It is also found that the micro-damage in the concrete is of self-similarity,and in the context of the fractal dimension,the pore evolution can be quantitatively characterized across different sizes,ranging from local to global levels,before and after freezing and thawing.
