单脉冲搜索作为脉冲星探测的有力工具,在探测旋转射电暂现源以及快速射电暴中扮演着重要角色。为了从海量的射电巡天数据中快速筛选出最有价值的单脉冲搜索候选体,候选体识别已经从早期启发式阈值判断发展到基于机器学习自动识别。对于F...单脉冲搜索作为脉冲星探测的有力工具,在探测旋转射电暂现源以及快速射电暴中扮演着重要角色。为了从海量的射电巡天数据中快速筛选出最有价值的单脉冲搜索候选体,候选体识别已经从早期启发式阈值判断发展到基于机器学习自动识别。对于FAST观测,研究了基于机器学习的单脉冲搜索候选体识别应用到CRAFTS(the commensal radio astronomy FAST survey)超宽带脉冲星数据的性能表现。在评估过程中,使用单脉冲事件组识别(SPEGID)和单脉冲搜索器(SPS)两类自动识别方法,通过7种不同机器学习分类器对CRAFTS基准数据集产生的单脉冲搜索候选体进行自动识别;作为对比,也使用了启发式阈值判断的方法(RRATtrap和Clusterrank)。结果表明,SPEGID具有最好的性能表现(最高的F1-score值95.1%、次高的召回率95.4%、最低的假阳性率4.7%),SPS具有最快的筛选速度(平均每小时筛选4010个候选体)。通过对比分析结果,探讨了如何基于FAST观测数据开展高效的单脉冲搜索候选体识别。展开更多
对大规模射电天文巡天项目产生的数据进行单脉冲搜索会产生数以亿计的脉冲星候选体。处理了500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)多科学目标同时扫描巡天(The Commensal Radio Astrono...对大规模射电天文巡天项目产生的数据进行单脉冲搜索会产生数以亿计的脉冲星候选体。处理了500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)多科学目标同时扫描巡天(The Commensal Radio Astronomy FAST Survey,CRAFTS)32万个超宽带数据文件,得到5万个脉冲星候选体。针对CRAFTS单脉冲搜索试验结果中脉冲星候选体仅有1.5%真正是脉冲星信号的问题,提出3个显著区分脉冲星信号和干扰的特征,并应用于单脉冲筛选流程。试验结果表明,改进后的单脉冲筛选工具将需要人工检查脉冲星候选体的数量降低了20%,一定程度上提高了CRAFTS巡天数据的单脉冲搜索效率。展开更多
The progress of economic globalization,the rapid growth of international trade,and the maritime transportation has played an increasingly significant role in the international supply chain.As a result,worldwide seapor...The progress of economic globalization,the rapid growth of international trade,and the maritime transportation has played an increasingly significant role in the international supply chain.As a result,worldwide seaports have suffered from a central problem,which appears in the form of massive amounts of fuel consumed and exhaust gas fumes emitted from the ships while berthed.Many ports have taken the necessary precautions to overcome this problem,while others still suffer due to the presence of technical and financial constraints.In this paper,the barriers,interconnection standards,rules,regulations,power sources,and economic and environmental analysis related to ships,shore-side power were studied in efforts to find a solution to overcome his problem.As a case study,this paper investigates the practicability,costs and benefits of switching from onboard ship auxiliary engines to shore-side power connection for high-speed crafts called Alkahera while berthed at the port of Safaga,Egypt.The results provide the national electricity grid concept as the best economical selection with 49.03 percent of annual cost saving.Moreover,environmentally,it could achieve an annual reduction in exhaust gas emissions of CO2,CO,NOx,P.M,and SO2by 276,2.32,18.87,0.825 and 3.84 tons,respectively.展开更多
An efficient asymmetric Friedel-Crafts reaction has been developed for the synthesis of optically active quaternaryα‐aminophosphonates with up to98%ee.The synthesis involves the reaction of cyclicα‐ketiminophospho...An efficient asymmetric Friedel-Crafts reaction has been developed for the synthesis of optically active quaternaryα‐aminophosphonates with up to98%ee.The synthesis involves the reaction of cyclicα‐ketiminophosphonates with indoles using an H8‐BINOL‐derived chiral phosphoric acid(CPA)catalyst that bears electron‐withdrawing3,5‐ditrifluoromethylphenyl substituents on its3‐and3′‐positions.This Friedel-Crafts reaction of cyclicα‐ketiminophosphonates was also successful with pyrrole.展开更多
In 1996,the Institute for the History of Natural Sciences of the Chinese Academy of Sciences began work on the Complete Collection of Traditional Ounese Arts and Crafts(Zhongguo chuantong ongyi quanji中国传统工艺全集)...In 1996,the Institute for the History of Natural Sciences of the Chinese Academy of Sciences began work on the Complete Collection of Traditional Ounese Arts and Crafts(Zhongguo chuantong ongyi quanji中国传统工艺全集).In 2016,Elephant Press published this twenty-volume magnum opus under the chief editorship of Lu Yongxiang路甬祥.This rich and informative book series systematically details traditional arts and crafts in over ten main categories that demonstrate Chinese scholars'mastery of fields such as lacquerware,ceramics,metal crafts,machinery,spinning and weaving,dyeing,brewing,processing of traditional Chinese materia medica,papermaking and printing,sculpting,and armor restoration.The authors are well versed in traditional Chinese arts and crafts and have the pertinent academic credentials,elevating research on the subject to a new level and breadth.However,the Complete Collection has not yet covered all significant arts and crafts,and the cultural implications have still to be explored.展开更多
On September 17,the Craftsmanship:Chinese Traditional Arts and Crafts Exhibition,jointly sponsored by China Cultural Center in Tanzania,Network of International Culturalink Entities and Quanzhou Art Museum was open to...On September 17,the Craftsmanship:Chinese Traditional Arts and Crafts Exhibition,jointly sponsored by China Cultural Center in Tanzania,Network of International Culturalink Entities and Quanzhou Art Museum was open to the public in China Cultural Center in Tanzania.展开更多
文摘单脉冲搜索作为脉冲星探测的有力工具,在探测旋转射电暂现源以及快速射电暴中扮演着重要角色。为了从海量的射电巡天数据中快速筛选出最有价值的单脉冲搜索候选体,候选体识别已经从早期启发式阈值判断发展到基于机器学习自动识别。对于FAST观测,研究了基于机器学习的单脉冲搜索候选体识别应用到CRAFTS(the commensal radio astronomy FAST survey)超宽带脉冲星数据的性能表现。在评估过程中,使用单脉冲事件组识别(SPEGID)和单脉冲搜索器(SPS)两类自动识别方法,通过7种不同机器学习分类器对CRAFTS基准数据集产生的单脉冲搜索候选体进行自动识别;作为对比,也使用了启发式阈值判断的方法(RRATtrap和Clusterrank)。结果表明,SPEGID具有最好的性能表现(最高的F1-score值95.1%、次高的召回率95.4%、最低的假阳性率4.7%),SPS具有最快的筛选速度(平均每小时筛选4010个候选体)。通过对比分析结果,探讨了如何基于FAST观测数据开展高效的单脉冲搜索候选体识别。
文摘对大规模射电天文巡天项目产生的数据进行单脉冲搜索会产生数以亿计的脉冲星候选体。处理了500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)多科学目标同时扫描巡天(The Commensal Radio Astronomy FAST Survey,CRAFTS)32万个超宽带数据文件,得到5万个脉冲星候选体。针对CRAFTS单脉冲搜索试验结果中脉冲星候选体仅有1.5%真正是脉冲星信号的问题,提出3个显著区分脉冲星信号和干扰的特征,并应用于单脉冲筛选流程。试验结果表明,改进后的单脉冲筛选工具将需要人工检查脉冲星候选体的数量降低了20%,一定程度上提高了CRAFTS巡天数据的单脉冲搜索效率。
文摘The progress of economic globalization,the rapid growth of international trade,and the maritime transportation has played an increasingly significant role in the international supply chain.As a result,worldwide seaports have suffered from a central problem,which appears in the form of massive amounts of fuel consumed and exhaust gas fumes emitted from the ships while berthed.Many ports have taken the necessary precautions to overcome this problem,while others still suffer due to the presence of technical and financial constraints.In this paper,the barriers,interconnection standards,rules,regulations,power sources,and economic and environmental analysis related to ships,shore-side power were studied in efforts to find a solution to overcome his problem.As a case study,this paper investigates the practicability,costs and benefits of switching from onboard ship auxiliary engines to shore-side power connection for high-speed crafts called Alkahera while berthed at the port of Safaga,Egypt.The results provide the national electricity grid concept as the best economical selection with 49.03 percent of annual cost saving.Moreover,environmentally,it could achieve an annual reduction in exhaust gas emissions of CO2,CO,NOx,P.M,and SO2by 276,2.32,18.87,0.825 and 3.84 tons,respectively.
基金supported by the National Natural Science Foundation of China(21532006,21690074)~~
文摘An efficient asymmetric Friedel-Crafts reaction has been developed for the synthesis of optically active quaternaryα‐aminophosphonates with up to98%ee.The synthesis involves the reaction of cyclicα‐ketiminophosphonates with indoles using an H8‐BINOL‐derived chiral phosphoric acid(CPA)catalyst that bears electron‐withdrawing3,5‐ditrifluoromethylphenyl substituents on its3‐and3′‐positions.This Friedel-Crafts reaction of cyclicα‐ketiminophosphonates was also successful with pyrrole.
文摘In 1996,the Institute for the History of Natural Sciences of the Chinese Academy of Sciences began work on the Complete Collection of Traditional Ounese Arts and Crafts(Zhongguo chuantong ongyi quanji中国传统工艺全集).In 2016,Elephant Press published this twenty-volume magnum opus under the chief editorship of Lu Yongxiang路甬祥.This rich and informative book series systematically details traditional arts and crafts in over ten main categories that demonstrate Chinese scholars'mastery of fields such as lacquerware,ceramics,metal crafts,machinery,spinning and weaving,dyeing,brewing,processing of traditional Chinese materia medica,papermaking and printing,sculpting,and armor restoration.The authors are well versed in traditional Chinese arts and crafts and have the pertinent academic credentials,elevating research on the subject to a new level and breadth.However,the Complete Collection has not yet covered all significant arts and crafts,and the cultural implications have still to be explored.
文摘On September 17,the Craftsmanship:Chinese Traditional Arts and Crafts Exhibition,jointly sponsored by China Cultural Center in Tanzania,Network of International Culturalink Entities and Quanzhou Art Museum was open to the public in China Cultural Center in Tanzania.
