The effect of prenatal exposure to ambient particulate matter(PM)on birth weight varies considerably across studies,and the findings remain inconclusive.In this study,we conducted a meta-analysis to assess the associa...The effect of prenatal exposure to ambient particulate matter(PM)on birth weight varies considerably across studies,and the findings remain inconclusive.In this study,we conducted a meta-analysis to assess the associations between exposure to PM_(2.5) and PM10 and birth weight.A total of 74 studies were identified through searches in Web of Science,PubMed,Embase,and Ovid Medline,as well as manual searches,up to October 2024.We found that for each 10μg/m^(3) increase in PM_(2.5),the risk of low birth weight(LBW)increased significantly during the entire pregnancy(odds ratio[OR]=2.41,95%confidence interval[CI]:1.99–2.91)and in all trimesters.Similarly,for every 10μg/m^(3) increase in PM10 concentration,the risk of LBW increased significantly during the entire pregnancy(OR=1.46,95%CI:1.16–1.84).Subgroup analysis by maternal age for PM_(2.5) showed that mothers aged 30 and above had a significantly higher risk of LBW(OR=3.69,95%CI:2.81–4.84),compared with those under 30.In conclusion,maternal exposure to PM_(2.5) and PM_(10) is associated with an increased risk of LBW across all trimesters.Additionally,mothers aged 30 and above are at a higher risk of LBW,compared with younger mothers.Further research is needed to clarify the biological mechanisms by which PM pollution may contribute to LBW.展开更多
高性能同轴电缆网络(High Performance Network Over Coax,HINOC)技术是一种光纤同轴混合接入技术,已发展至第3代。为了实现万兆以太网的接入速率,第3代HINOC引入了多信道绑定机制。但该机制在有效扩展HINOC网络信道带宽的同时易导致HIM...高性能同轴电缆网络(High Performance Network Over Coax,HINOC)技术是一种光纤同轴混合接入技术,已发展至第3代。为了实现万兆以太网的接入速率,第3代HINOC引入了多信道绑定机制。但该机制在有效扩展HINOC网络信道带宽的同时易导致HIMAC(HINOC Medium Access Control)拆帧端接收的数据流失序。针对该问题,文中提出了一种拆帧重排序方法。通过重排序队列缓存管理、入队逻辑地址计算、超时判断及清空以及出队判断等关键技术的设计和实现来解决多信道绑定机制引起的拆帧乱序问题,并对其关键功能点进行仿真验证和板级验证。实验结果表明,所提方法能够有效处理多信道绑定导致的乱序问题,并且能够确保系统在遇到错误情况时稳定运行,具有较强的鲁棒性,满足万兆同轴宽带接入HIMAC 3.0的功能和性能要求。展开更多
本文探究了一种基于RELAP5程序的球床模块式高温气冷堆模拟分析方法。以山东石岛湾高温气冷堆核电站示范工程(High Temperature Reactor-Pebble bed Module,HTR-PM)为研究对象,依据其系统特性进行模型简化与模块划分,建立了包括反应堆...本文探究了一种基于RELAP5程序的球床模块式高温气冷堆模拟分析方法。以山东石岛湾高温气冷堆核电站示范工程(High Temperature Reactor-Pebble bed Module,HTR-PM)为研究对象,依据其系统特性进行模型简化与模块划分,建立了包括反应堆堆芯流道、燃料热构件、横向导热构件及蒸汽发生器的全回路系统模型。基于所建HTR-PM模型,开展100%额定功率和50%额定功率下的平衡堆芯热工水力分析,同时研究了旁流份额对堆芯热效应的影响;在此基础上,选择保守旁流份额开展全厂断电叠加未能停堆(Anticipated Transient without Scram,ATWS)事故的模拟。结果表明:针对稳态平衡堆芯计算得到的回路主参数及堆芯燃料、冷却剂的温度分布与参考软件THERMIX的计算结果吻合良好;反应堆结构设计中,过高的旁流份额会导致堆芯局部燃料及冷却剂温度过高,通过优化堆芯结构降低旁流份额对保障堆芯热工安全具有重要意义;全厂断电ATWS事故中,燃料最高温度低于设计限值,再次验证球床模块式高温气冷堆的固有安全性。本研究基于独立的系统分析程序,实现对现有球床模块式高温气冷堆分析工具的补充和扩展;提供的详细的建模分析方法与丰富的数据,可为RELAP5程序在球床模块式高温气冷堆的复杂热工水力与事故分析的全面应用提供参考。展开更多
文摘The effect of prenatal exposure to ambient particulate matter(PM)on birth weight varies considerably across studies,and the findings remain inconclusive.In this study,we conducted a meta-analysis to assess the associations between exposure to PM_(2.5) and PM10 and birth weight.A total of 74 studies were identified through searches in Web of Science,PubMed,Embase,and Ovid Medline,as well as manual searches,up to October 2024.We found that for each 10μg/m^(3) increase in PM_(2.5),the risk of low birth weight(LBW)increased significantly during the entire pregnancy(odds ratio[OR]=2.41,95%confidence interval[CI]:1.99–2.91)and in all trimesters.Similarly,for every 10μg/m^(3) increase in PM10 concentration,the risk of LBW increased significantly during the entire pregnancy(OR=1.46,95%CI:1.16–1.84).Subgroup analysis by maternal age for PM_(2.5) showed that mothers aged 30 and above had a significantly higher risk of LBW(OR=3.69,95%CI:2.81–4.84),compared with those under 30.In conclusion,maternal exposure to PM_(2.5) and PM_(10) is associated with an increased risk of LBW across all trimesters.Additionally,mothers aged 30 and above are at a higher risk of LBW,compared with younger mothers.Further research is needed to clarify the biological mechanisms by which PM pollution may contribute to LBW.
文摘高性能同轴电缆网络(High Performance Network Over Coax,HINOC)技术是一种光纤同轴混合接入技术,已发展至第3代。为了实现万兆以太网的接入速率,第3代HINOC引入了多信道绑定机制。但该机制在有效扩展HINOC网络信道带宽的同时易导致HIMAC(HINOC Medium Access Control)拆帧端接收的数据流失序。针对该问题,文中提出了一种拆帧重排序方法。通过重排序队列缓存管理、入队逻辑地址计算、超时判断及清空以及出队判断等关键技术的设计和实现来解决多信道绑定机制引起的拆帧乱序问题,并对其关键功能点进行仿真验证和板级验证。实验结果表明,所提方法能够有效处理多信道绑定导致的乱序问题,并且能够确保系统在遇到错误情况时稳定运行,具有较强的鲁棒性,满足万兆同轴宽带接入HIMAC 3.0的功能和性能要求。
文摘本文探究了一种基于RELAP5程序的球床模块式高温气冷堆模拟分析方法。以山东石岛湾高温气冷堆核电站示范工程(High Temperature Reactor-Pebble bed Module,HTR-PM)为研究对象,依据其系统特性进行模型简化与模块划分,建立了包括反应堆堆芯流道、燃料热构件、横向导热构件及蒸汽发生器的全回路系统模型。基于所建HTR-PM模型,开展100%额定功率和50%额定功率下的平衡堆芯热工水力分析,同时研究了旁流份额对堆芯热效应的影响;在此基础上,选择保守旁流份额开展全厂断电叠加未能停堆(Anticipated Transient without Scram,ATWS)事故的模拟。结果表明:针对稳态平衡堆芯计算得到的回路主参数及堆芯燃料、冷却剂的温度分布与参考软件THERMIX的计算结果吻合良好;反应堆结构设计中,过高的旁流份额会导致堆芯局部燃料及冷却剂温度过高,通过优化堆芯结构降低旁流份额对保障堆芯热工安全具有重要意义;全厂断电ATWS事故中,燃料最高温度低于设计限值,再次验证球床模块式高温气冷堆的固有安全性。本研究基于独立的系统分析程序,实现对现有球床模块式高温气冷堆分析工具的补充和扩展;提供的详细的建模分析方法与丰富的数据,可为RELAP5程序在球床模块式高温气冷堆的复杂热工水力与事故分析的全面应用提供参考。
