Turbulent dispersed multiphase flows,including gas-particle,gas-droplet and bubble-liquid flows,are widely encountered in various engineering facilities.Modeling of two-phase turbulence,in particular the dispersed pha...Turbulent dispersed multiphase flows,including gas-particle,gas-droplet and bubble-liquid flows,are widely encountered in various engineering facilities.Modeling of two-phase turbulence,in particular the dispersed phase turbulence,is the key problem in the Eulerian-Eulerian simulation of practical dispersed multiphase flows.Although different models were developed and used,the experimental validation shows that they cannot always give satisfactory prediction results.In this paper the present author give a detailed review of the unified second-order moment (USM),k-k p and nonlinear k-k p two-phase turbulence models,proposed by him.The derivation and closure of these models are described in detail and the experimental validation and application of these models are extensively discussed.展开更多
前不久，佳能正式发布了L级EF远摄变焦镜头瓿晶EF70-200mm f／4L IS II USM，让拥有优秀便携性的具备F4恒定光圈的佳能“小三元”系列实现阵容升级。新款毡F70—200mm f／4L IS II USM镜头往IS影像稳定器、抑制鬼影和眩光、最近对焦距...前不久，佳能正式发布了L级EF远摄变焦镜头瓿晶EF70-200mm f／4L IS II USM，让拥有优秀便携性的具备F4恒定光圈的佳能“小三元”系列实现阵容升级。新款毡F70—200mm f／4L IS II USM镜头往IS影像稳定器、抑制鬼影和眩光、最近对焦距离、可靠性以及外观等方面，进行了多方位提升，同时延续了佳能L级镜头高画质特点，捧保持紧凑、轻量化的优势。展开更多
日前,佳能（中国）正式发布一代大光圈L级广角定焦镜头EF 35mm f／1.4L II USM，新镜头最大的特点是应用了佳能最新研发的BR镜片。EF 35mm f／1.4L II USM将于10月正式上市，售价1799美元，约合1．15万人民币。EF 35mm f/1.4L II USM采...日前,佳能（中国）正式发布一代大光圈L级广角定焦镜头EF 35mm f／1.4L II USM，新镜头最大的特点是应用了佳能最新研发的BR镜片。EF 35mm f／1.4L II USM将于10月正式上市，售价1799美元，约合1．15万人民币。EF 35mm f/1.4L II USM采用11组、14片镜头光学结构，第一片镜片采用SWC亚波长结构镀膜，具有良好的防反射效果，从而有效抑制眩光和鬼影的产生。展开更多
基金supported by the National Key Project of Fundamental Research of China (Grant No.G1999-0222-07-08)the National Natural Science Foundation of China (Grant Nos.50736006 and 50606026)the Foundation of State Key Laboratory of Engines,Tianjin University (Grant No.K2010-07)
文摘Turbulent dispersed multiphase flows,including gas-particle,gas-droplet and bubble-liquid flows,are widely encountered in various engineering facilities.Modeling of two-phase turbulence,in particular the dispersed phase turbulence,is the key problem in the Eulerian-Eulerian simulation of practical dispersed multiphase flows.Although different models were developed and used,the experimental validation shows that they cannot always give satisfactory prediction results.In this paper the present author give a detailed review of the unified second-order moment (USM),k-k p and nonlinear k-k p two-phase turbulence models,proposed by him.The derivation and closure of these models are described in detail and the experimental validation and application of these models are extensively discussed.
文摘前不久，佳能正式发布了L级EF远摄变焦镜头瓿晶EF70-200mm f／4L IS II USM，让拥有优秀便携性的具备F4恒定光圈的佳能“小三元”系列实现阵容升级。新款毡F70—200mm f／4L IS II USM镜头往IS影像稳定器、抑制鬼影和眩光、最近对焦距离、可靠性以及外观等方面，进行了多方位提升，同时延续了佳能L级镜头高画质特点，捧保持紧凑、轻量化的优势。
文摘日前,佳能（中国）正式发布一代大光圈L级广角定焦镜头EF 35mm f／1.4L II USM，新镜头最大的特点是应用了佳能最新研发的BR镜片。EF 35mm f／1.4L II USM将于10月正式上市，售价1799美元，约合1．15万人民币。EF 35mm f/1.4L II USM采用11组、14片镜头光学结构，第一片镜片采用SWC亚波长结构镀膜，具有良好的防反射效果，从而有效抑制眩光和鬼影的产生。
