为评估处置库的安全性,核素化学形态信息是准确预测核素的运移行为研究的前提。鉴于我国核能工业的迅速发展以及建立环境中核素的确认需求,在我国开展处置库周围核素的化学形态研究具有十分重要的意义。针对地下水中元素种态分布的研究...为评估处置库的安全性,核素化学形态信息是准确预测核素的运移行为研究的前提。鉴于我国核能工业的迅速发展以及建立环境中核素的确认需求,在我国开展处置库周围核素的化学形态研究具有十分重要的意义。针对地下水中元素种态分布的研究需求,以JAVA为开发工具、MySQL作为数据库、Tomcat为容器,开发了一套B/S架构的元素种态分布模拟软件。针对模拟计算中遇到的化学反应平衡非线性方程组求解收敛困难的问题,引入了根据化学反应势能求解的方法和反应因子控制迭代步长,实现了对化学反应非线性方程快速地求解,并可拓展多相平衡计算。以塔木素地下水中镎为考察对象,利用所开发化学形态模拟软件(simulation software on chemical species,SSCS)计算环境中镎的形态和量,并对比PHREEQC的计算结果,相对偏差在10%以内,针对环境中痕量元素的分布,提供了理论计算的解决方案。展开更多
网络和信息安全是事关国家安全和国家发展、事关广大人民群众工作生活的重大战略问题。上海科技大学信息科学与技术学院系统与安全中心(System and Security Center,以下简称“SSC”)长期关注计算机系统优化设计和保护信息安全与隐私,...网络和信息安全是事关国家安全和国家发展、事关广大人民群众工作生活的重大战略问题。上海科技大学信息科学与技术学院系统与安全中心(System and Security Center,以下简称“SSC”)长期关注计算机系统优化设计和保护信息安全与隐私,并开展相关研究。近期,SSC在信息安全与数据隐私方面取得一系列重要进展,尤其在安全与隐私领域四大知名学术会议上,即IEEE S&P、ACM CCS、NDSS和USENIX Security,第一次实现了成果发表的“大满贯”。展开更多
文章基于互联电网安全稳定控制系统(security and stability control system,SSCS)分层结构和有向指令传输,建立概率加权有向图模型;由于该模型不具有布尔特性,基于路径搜索算法,提出概率加权全连通矩阵;从维护有功平衡能力角度,提出SSC...文章基于互联电网安全稳定控制系统(security and stability control system,SSCS)分层结构和有向指令传输,建立概率加权有向图模型;由于该模型不具有布尔特性,基于路径搜索算法,提出概率加权全连通矩阵;从维护有功平衡能力角度,提出SSCS功能可靠性指标。为提高SSCS可靠性,提出功能可靠性指标对直流线路可靠性参数的灵敏度模型。研究结果表明:上层控制站点和连接通道较多的控制站点对SSCS可靠性影响较大;提高系统结构的可靠性、增加可调节容量,有助于改善功能可靠性和提高大型跨区电网频率稳定水平。展开更多
The sea surface temperature(SST)and sea surface suspended matter concentration data in the Bohai Sea were collected by multiple NOAA satellites from 1985 to 2018.The background calibration method was used to correct t...The sea surface temperature(SST)and sea surface suspended matter concentration data in the Bohai Sea were collected by multiple NOAA satellites from 1985 to 2018.The background calibration method was used to correct the systematic errors caused by the long-term observations through multiple NOAA satellites in this paper.Then,we studied the long-term variations of the sea surface temperature(SST)and sea surface suspended matter concentration(SSC)and their response to ENSO events in the Bohai Sea.Our results show that the SST and SSC of the Bohai Sea have been increasing since 1985,with an average rate of 0.04℃per year for SST,which is higher than the global average.The average increasing rate of SSC was 0.51 mg L^(-1)yr^(-1),which may be mainly due to the enhancement of winter monsoon in the Bohai.In winter,the SST and SSC of the Bohai Sea were higher in El Niño years than in La Niña years.In El Niño years,the ocean circulations were the main factor affecting the variation in SST.The robust circulation system caused by the strong winter monsoon enhances the water exchange between the cold water of the Bohai Sea and the warm water of the Yellow Sea,resulting in a higher SST in La Niña years.In summer,the SSTs of the Bohai Sea were lower in El Niño years than those in the La Niña years because of the decrease of the SST in the Western Pacific Ocean,the weakening of the subtropical high in the western Pacific,and its eastward shift caused by the El Niño events.展开更多
文摘为评估处置库的安全性,核素化学形态信息是准确预测核素的运移行为研究的前提。鉴于我国核能工业的迅速发展以及建立环境中核素的确认需求,在我国开展处置库周围核素的化学形态研究具有十分重要的意义。针对地下水中元素种态分布的研究需求,以JAVA为开发工具、MySQL作为数据库、Tomcat为容器,开发了一套B/S架构的元素种态分布模拟软件。针对模拟计算中遇到的化学反应平衡非线性方程组求解收敛困难的问题,引入了根据化学反应势能求解的方法和反应因子控制迭代步长,实现了对化学反应非线性方程快速地求解,并可拓展多相平衡计算。以塔木素地下水中镎为考察对象,利用所开发化学形态模拟软件(simulation software on chemical species,SSCS)计算环境中镎的形态和量,并对比PHREEQC的计算结果,相对偏差在10%以内,针对环境中痕量元素的分布,提供了理论计算的解决方案。
文摘文章基于互联电网安全稳定控制系统(security and stability control system,SSCS)分层结构和有向指令传输,建立概率加权有向图模型;由于该模型不具有布尔特性,基于路径搜索算法,提出概率加权全连通矩阵;从维护有功平衡能力角度,提出SSCS功能可靠性指标。为提高SSCS可靠性,提出功能可靠性指标对直流线路可靠性参数的灵敏度模型。研究结果表明:上层控制站点和连接通道较多的控制站点对SSCS可靠性影响较大;提高系统结构的可靠性、增加可调节容量,有助于改善功能可靠性和提高大型跨区电网频率稳定水平。
基金supported by the National Natural Science Foundation of China(No.42121005)。
文摘The sea surface temperature(SST)and sea surface suspended matter concentration data in the Bohai Sea were collected by multiple NOAA satellites from 1985 to 2018.The background calibration method was used to correct the systematic errors caused by the long-term observations through multiple NOAA satellites in this paper.Then,we studied the long-term variations of the sea surface temperature(SST)and sea surface suspended matter concentration(SSC)and their response to ENSO events in the Bohai Sea.Our results show that the SST and SSC of the Bohai Sea have been increasing since 1985,with an average rate of 0.04℃per year for SST,which is higher than the global average.The average increasing rate of SSC was 0.51 mg L^(-1)yr^(-1),which may be mainly due to the enhancement of winter monsoon in the Bohai.In winter,the SST and SSC of the Bohai Sea were higher in El Niño years than in La Niña years.In El Niño years,the ocean circulations were the main factor affecting the variation in SST.The robust circulation system caused by the strong winter monsoon enhances the water exchange between the cold water of the Bohai Sea and the warm water of the Yellow Sea,resulting in a higher SST in La Niña years.In summer,the SSTs of the Bohai Sea were lower in El Niño years than those in the La Niña years because of the decrease of the SST in the Western Pacific Ocean,the weakening of the subtropical high in the western Pacific,and its eastward shift caused by the El Niño events.
