Conventional model tests and centrifuge tests are frequently used to investigate seepage erosion. However, the centrifugal test method may not be efficient according to the results of hydraulic conductivity tests and ...Conventional model tests and centrifuge tests are frequently used to investigate seepage erosion. However, the centrifugal test method may not be efficient according to the results of hydraulic conductivity tests and piping erosion tests. The reason why seepage deformation in model tests may deviate from similarity was first discussed in this work. Then, the similarity criterion for seepage deformation in porous media was improved based on the extended Darcy-Brinkman-Forchheimer equation. Finally, the coupled particle flow code–computational fluid dynamics(PFC-CFD) model at the mesoscopic level was proposed to verify the derived similarity criterion. The proposed model maximizes its potential to simulate seepage erosion via the discrete element method and satisfy the similarity criterion by adjusting particle size. The numerical simulations achieved identical results with the prototype, thus indicating that the PFC-CFD model that satisfies the improved similarity criterion can accurately reproduce the processes of seepage erosion at the mesoscopic level.展开更多
The purpose of this study is to design a tool, adapted to students＇ individual contexts and to enable students to reflect on their understanding of media characteristics. AHP （analytic hierarchy process） is a struc...The purpose of this study is to design a tool, adapted to students＇ individual contexts and to enable students to reflect on their understanding of media characteristics. AHP （analytic hierarchy process） is a structured technique for organizing and analyzing complex decisions. Using AHP, students have to define appropriate criteria and priorities for using media. It is expected that students＂ understanding of the characteristics of different types of media will emerge through reflection. Seventy two university students took part in this research. They were asked to prioritize their ways.of obtaining information about current affairs using sets of media such as TV, books, newspapers and web pages, Twitter and Facebook. AHP enables us to visualize a ＂real＂ understanding of media characteristics and students can reflect on that basis. As far as ＂information sources and media＂ is concerned, a few students indicated that it was the information source itself that was important rather than the type of media. Our tool fulfils the role of encouraging this type of reflection.展开更多
Based on homogeneous balance method, sofiton solutions to a generalized nonlinear Sehr6dinger equation （NLSE） with varying coefficients have been gotten. Our results indicate that a new family of vortex or petal-lik...Based on homogeneous balance method, sofiton solutions to a generalized nonlinear Sehr6dinger equation （NLSE） with varying coefficients have been gotten. Our results indicate that a new family of vortex or petal-like spatial solitons can be formed in the Kerr nonlinear media in the cylindrical symmetric geometry. It is shown by numerical simulation that these soliton profiles are stable.展开更多
We obtain exact spatiotemporal similaritons to a （3＋ l）-dimensional inhomogeneous nonlinear Schrodinger equation, which describes the propagation of optical pulses in a cubic-quintic nonlinearity medium with distri...We obtain exact spatiotemporal similaritons to a （3＋ l）-dimensional inhomogeneous nonlinear Schrodinger equation, which describes the propagation of optical pulses in a cubic-quintic nonlinearity medium with distributed dispersion and gain. A one-to-one correspondence between such self-similar waves and solutions of the elliptic equation is found when a certain compatibility condition is satisfied. Based on exact solutions, we discuss evolutional behaviors of self-similar cnoidal waves and chirped similaritons in two kind of typicai soliton control systems. Moreover, the comparison between chirped similaritons and chirp-free solitons is given.展开更多
The （1＋1）-dimensional F-expansion technique and the homogeneous nonlinear balance principle have been generalized and applied for solving exact solutions to a general （3＋1）-dimensional nonlinear Schr6dinger equa...The （1＋1）-dimensional F-expansion technique and the homogeneous nonlinear balance principle have been generalized and applied for solving exact solutions to a general （3＋1）-dimensional nonlinear Schr6dinger equation （NLSE） with varying coefficients and a harmonica potential. We found that there exist two kinds of soliton solutions. The evolution features of exact solutions have been numerically studied. The （3＋1）D soliton solutions may help us to understand the nonlinear wave propagation in the nonlinear media such as classical optical waves and the matter waves of the Bose-Einstein condensates.展开更多
58.31 多孔鉄淦氧磁心的構造和用途作者:H. W. Abbott, J. J. Surau 原名:Multihole Ferrite Core Configuratious and Applications 原載:P.I.R.E.Aug.1957 摘写:邮电科学研究院資料組 本文再次介紹了对磁通量轉移器(Transfluxor)所进...58.31 多孔鉄淦氧磁心的構造和用途作者:H. W. Abbott, J. J. Surau 原名:Multihole Ferrite Core Configuratious and Applications 原載:P.I.R.E.Aug.1957 摘写:邮电科学研究院資料組 本文再次介紹了对磁通量轉移器(Transfluxor)所进行的工作。它是一个多孔铁淦氧圓片,可用作控制和計算机电路的开关元件。利用这种元件,设计者有可能設計出許多新颖和复杂的記忆和门电路。如文中所指出的,应用一个六孔磁通量轉移器。展开更多
基金Project(51309086)supported by the National Natural Science Foundation of ChinaProject(20110094120002)supported by the Ministry Education Foundation of ChinaProjects(2014B04914,2011B07214)supported by the Fundamental Research Funds for the Central Universities,China
文摘Conventional model tests and centrifuge tests are frequently used to investigate seepage erosion. However, the centrifugal test method may not be efficient according to the results of hydraulic conductivity tests and piping erosion tests. The reason why seepage deformation in model tests may deviate from similarity was first discussed in this work. Then, the similarity criterion for seepage deformation in porous media was improved based on the extended Darcy-Brinkman-Forchheimer equation. Finally, the coupled particle flow code–computational fluid dynamics(PFC-CFD) model at the mesoscopic level was proposed to verify the derived similarity criterion. The proposed model maximizes its potential to simulate seepage erosion via the discrete element method and satisfy the similarity criterion by adjusting particle size. The numerical simulations achieved identical results with the prototype, thus indicating that the PFC-CFD model that satisfies the improved similarity criterion can accurately reproduce the processes of seepage erosion at the mesoscopic level.
文摘The purpose of this study is to design a tool, adapted to students＇ individual contexts and to enable students to reflect on their understanding of media characteristics. AHP （analytic hierarchy process） is a structured technique for organizing and analyzing complex decisions. Using AHP, students have to define appropriate criteria and priorities for using media. It is expected that students＂ understanding of the characteristics of different types of media will emerge through reflection. Seventy two university students took part in this research. They were asked to prioritize their ways.of obtaining information about current affairs using sets of media such as TV, books, newspapers and web pages, Twitter and Facebook. AHP enables us to visualize a ＂real＂ understanding of media characteristics and students can reflect on that basis. As far as ＂information sources and media＂ is concerned, a few students indicated that it was the information source itself that was important rather than the type of media. Our tool fulfils the role of encouraging this type of reflection.
基金Supported by the Xianning University Foundation of Hubei Province under Grant No.2010CDB05103Xianning University Foundation under Grant No.BK001
文摘Based on homogeneous balance method, sofiton solutions to a generalized nonlinear Sehr6dinger equation （NLSE） with varying coefficients have been gotten. Our results indicate that a new family of vortex or petal-like spatial solitons can be formed in the Kerr nonlinear media in the cylindrical symmetric geometry. It is shown by numerical simulation that these soliton profiles are stable.
基金Supported by the National Natural Science Foundation of China under Grant No.10974177by the Ministry of Science and Technology of China under Grant No.2010DFA04690
文摘We obtain exact spatiotemporal similaritons to a （3＋ l）-dimensional inhomogeneous nonlinear Schrodinger equation, which describes the propagation of optical pulses in a cubic-quintic nonlinearity medium with distributed dispersion and gain. A one-to-one correspondence between such self-similar waves and solutions of the elliptic equation is found when a certain compatibility condition is satisfied. Based on exact solutions, we discuss evolutional behaviors of self-similar cnoidal waves and chirped similaritons in two kind of typicai soliton control systems. Moreover, the comparison between chirped similaritons and chirp-free solitons is given.
基金Supported by National Science Foundation of China under Grant No. 2006CB921605
文摘The （1＋1）-dimensional F-expansion technique and the homogeneous nonlinear balance principle have been generalized and applied for solving exact solutions to a general （3＋1）-dimensional nonlinear Schr6dinger equation （NLSE） with varying coefficients and a harmonica potential. We found that there exist two kinds of soliton solutions. The evolution features of exact solutions have been numerically studied. The （3＋1）D soliton solutions may help us to understand the nonlinear wave propagation in the nonlinear media such as classical optical waves and the matter waves of the Bose-Einstein condensates.
文摘58.31 多孔鉄淦氧磁心的構造和用途作者:H. W. Abbott, J. J. Surau 原名:Multihole Ferrite Core Configuratious and Applications 原載:P.I.R.E.Aug.1957 摘写:邮电科学研究院資料組 本文再次介紹了对磁通量轉移器(Transfluxor)所进行的工作。它是一个多孔铁淦氧圓片,可用作控制和計算机电路的开关元件。利用这种元件,设计者有可能設計出許多新颖和复杂的記忆和门电路。如文中所指出的,应用一个六孔磁通量轉移器。
