We compare observed with predicted distributions of galaxy stellar masses M<sub>* </sub>and galaxy rest-frame ultra-violet luminosities per unit bandwidth L<sub>UV</sub>, in the redsh...We compare observed with predicted distributions of galaxy stellar masses M<sub>* </sub>and galaxy rest-frame ultra-violet luminosities per unit bandwidth L<sub>UV</sub>, in the redshift range z=2 to 13. The comparison is presented as a function of the comoving warm dark matter free-streaming cut-off wavenumber k<sub>fs</sub>. For this comparison the theory is a minimal extension of the Press-Schechter formalism with only two parameters: the star formation efficiency, and a proportionality factor between the star formation rate per galaxy and LUV</sub>. These two parameters are fixed to their values obtained prior to the James Webb Space Telescope (JWST) data. The purpose of this comparison is to identify if, and where, detailed astrophysical evolution is needed to account for the new JWST observations.展开更多
Araby is a short story by the famous Irish stream-of-consciousness writer James Joyce.Through a series of images,the novel expresses the theme of the story:the“mental paralysis”of Dubliners and the“spiritual Epiph...Araby is a short story by the famous Irish stream-of-consciousness writer James Joyce.Through a series of images,the novel expresses the theme of the story:the“mental paralysis”of Dubliners and the“spiritual Epiphany”of the little boy,which reflects the spiritual barren of Dubliners at that time.Through the analysis of the symbolic meaning of many images in the work,this paper reveals the social background and religious significance hidden behind the images.展开更多
做好重大科技项目的组织管理是实现抢占科技制高点目标的重要前提条件。本文以美国国家航空航天局(National Aeronautics and Space Administration,NASA)系列管理文件为分析对象,剖析其项目组织管理模式,并以投资近百亿美元、持续数十...做好重大科技项目的组织管理是实现抢占科技制高点目标的重要前提条件。本文以美国国家航空航天局(National Aeronautics and Space Administration,NASA)系列管理文件为分析对象,剖析其项目组织管理模式,并以投资近百亿美元、持续数十年的詹姆斯·韦布太空望远镜项目为例,对NASA重大项目预研管理过程进行分析。NASA将项目按照成本、风险、是否属于优先事项等分为3个类别进行管理,项目生命周期可以分为从“A前”(pre-A)到A、B直至F共7个阶段。韦布望远镜从1995年进入NASA的“A前阶段”,由3家单位独立开展概念研究;1999年7月从3家单位中遴选2家开始“A阶段”研究;2002年9月正式选择1家单位牵头开展“B阶段”研究。可供我国借鉴之处包括:项目组织方应发挥好“总体”角色,凝聚多方资源、提供长期稳定支持;新项目的酝酿需充分利用前期项目的科学、技术、管理人才基础;可利用“赛马制”等分阶段推进重大项目的实施,以降低不确定性和决策风险等。展开更多
文摘We compare observed with predicted distributions of galaxy stellar masses M<sub>* </sub>and galaxy rest-frame ultra-violet luminosities per unit bandwidth L<sub>UV</sub>, in the redshift range z=2 to 13. The comparison is presented as a function of the comoving warm dark matter free-streaming cut-off wavenumber k<sub>fs</sub>. For this comparison the theory is a minimal extension of the Press-Schechter formalism with only two parameters: the star formation efficiency, and a proportionality factor between the star formation rate per galaxy and LUV</sub>. These two parameters are fixed to their values obtained prior to the James Webb Space Telescope (JWST) data. The purpose of this comparison is to identify if, and where, detailed astrophysical evolution is needed to account for the new JWST observations.
文摘Araby is a short story by the famous Irish stream-of-consciousness writer James Joyce.Through a series of images,the novel expresses the theme of the story:the“mental paralysis”of Dubliners and the“spiritual Epiphany”of the little boy,which reflects the spiritual barren of Dubliners at that time.Through the analysis of the symbolic meaning of many images in the work,this paper reveals the social background and religious significance hidden behind the images.
文摘做好重大科技项目的组织管理是实现抢占科技制高点目标的重要前提条件。本文以美国国家航空航天局(National Aeronautics and Space Administration,NASA)系列管理文件为分析对象,剖析其项目组织管理模式,并以投资近百亿美元、持续数十年的詹姆斯·韦布太空望远镜项目为例,对NASA重大项目预研管理过程进行分析。NASA将项目按照成本、风险、是否属于优先事项等分为3个类别进行管理,项目生命周期可以分为从“A前”(pre-A)到A、B直至F共7个阶段。韦布望远镜从1995年进入NASA的“A前阶段”,由3家单位独立开展概念研究;1999年7月从3家单位中遴选2家开始“A阶段”研究;2002年9月正式选择1家单位牵头开展“B阶段”研究。可供我国借鉴之处包括:项目组织方应发挥好“总体”角色,凝聚多方资源、提供长期稳定支持;新项目的酝酿需充分利用前期项目的科学、技术、管理人才基础;可利用“赛马制”等分阶段推进重大项目的实施,以降低不确定性和决策风险等。
