Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The ...Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The variation characteristics of GWs during SSWs have always been an important issue.Using temperature data from January to March in 2014−2016,provided by the Constellation Observing System for Meteorology,Ionosphere and Climate(COSMIC)mission,we have analyzed global GW activity at 15−40 km in the Northern Hemisphere during SSW events.During the SSWs that we studied,the stratospheric temperature rose in one or two longitudinal regions in the Northern Hemisphere;the areas affected extended to the east of 90°W.During these SSWs,the potential energy density(E_(p)of GWs expanded and covered a larger range of longitude and altitude,exhibiting an eastward and downward extension.The E_(p)usually increased,while partially filtered by the eastward zonal winds.When zonal winds weakened or turned westward,E_(p)began to strengthen.After SSWs,the E_(p)usually decreased.These observations can serve as a reference for analyzing the interaction mechanism between SSWs and GWs in future work.展开更多
The paper describes research aimed at developing a configuration system to support theconceptual design of mechanical fasteners. A prototype configuration system has been developedwhich allows designers to interactive...The paper describes research aimed at developing a configuration system to support theconceptual design of mechanical fasteners. A prototype configuration system has been developedwhich allows designers to interactively configure fastener designs using geometric and functionalicons , freely without regard to physical constraints, with the aim of forming candidate designs.Candidate designs are then passed to the qualitative modeller which uses qualrtative reasoningtechniques to evaluate the configuration. Supporting the above design procedure is a knowledgebase which contains object descriptions of fasteners and fastener features (given in terms ofgeometry, function, performance, material,installation). Design rules (expressing spatial andcasual relationships of fastener features),which are required during the evaluation of candidatefastener configurations, are also contained in the knowledge base.展开更多
基金the National Science Foundation of Hunan Province,China(Grant No.2022JJ40471)the Research Foundation of the Education Bureau of Hunan Province,China(Grant No.22B0345)the Key Laboratory of Geospace Envi-ronment,Chinese Academy of Sciences,University of Science&Technology of China(Grant No.GE2023-01).
文摘Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The variation characteristics of GWs during SSWs have always been an important issue.Using temperature data from January to March in 2014−2016,provided by the Constellation Observing System for Meteorology,Ionosphere and Climate(COSMIC)mission,we have analyzed global GW activity at 15−40 km in the Northern Hemisphere during SSW events.During the SSWs that we studied,the stratospheric temperature rose in one or two longitudinal regions in the Northern Hemisphere;the areas affected extended to the east of 90°W.During these SSWs,the potential energy density(E_(p)of GWs expanded and covered a larger range of longitude and altitude,exhibiting an eastward and downward extension.The E_(p)usually increased,while partially filtered by the eastward zonal winds.When zonal winds weakened or turned westward,E_(p)began to strengthen.After SSWs,the E_(p)usually decreased.These observations can serve as a reference for analyzing the interaction mechanism between SSWs and GWs in future work.
文摘The paper describes research aimed at developing a configuration system to support theconceptual design of mechanical fasteners. A prototype configuration system has been developedwhich allows designers to interactively configure fastener designs using geometric and functionalicons , freely without regard to physical constraints, with the aim of forming candidate designs.Candidate designs are then passed to the qualitative modeller which uses qualrtative reasoningtechniques to evaluate the configuration. Supporting the above design procedure is a knowledgebase which contains object descriptions of fasteners and fastener features (given in terms ofgeometry, function, performance, material,installation). Design rules (expressing spatial andcasual relationships of fastener features),which are required during the evaluation of candidatefastener configurations, are also contained in the knowledge base.
