ABSTRACT The Global/Regional Assimilation and PrEdiction System （GRAPES） is the newgeneration numerical weather predic- tion （NWP） system developed by the China Meteorological Administration. It is a fully compre...ABSTRACT The Global/Regional Assimilation and PrEdiction System （GRAPES） is the newgeneration numerical weather predic- tion （NWP） system developed by the China Meteorological Administration. It is a fully compressible non-hydrostatical global/regional unified model that uses a traditional semi-Lagrangian advection scheme with cubic Lagrangian interpola tion （referred to as the SL_CL scheme）. The SL_CL scheme has been used in many operational NWP models, but there are still some deficiencies, such as the damping effects due to the interpolation and the relatively low accuracy. Based on Reich＇s semi-Lagrangian advection scheme （referred to as the R2007 scheme）, the Re_R2007 scheme that uses the low- and high-order B-spline function for interpolation at the departure point, is developed in this paper. One- and two-dimensional idealized tests in the rectangular coordinate system with uniform grid cells were conducted to compare the Re..R2007 scheme and the SL_CL scheme. The numerical results showed that： （1） the damping effects were remarkably reduced with the Re_R2007 scheme; and （2） the normalized errors of the Re_R2007 scheme were about 7.5 and 3 times smaller than those of the SL_CL scheme in one- and two-dimensional tests, respectively, indicating the higher accuracy of the Re..R2007 scheme. Furthermore, two solid-body rotation tests were conducted in the latitude-longitude spherical coordinate system with non uniform grid cells, which also verified the Re_R2007 scheme＇s advantages. Finally, in comparison with other global advection schemes, the Re_R2007 scheme was competitive in terms of accuracy and flow independence. An encouraging possibility for the application of the Re_R2007 scheme to the GRAPES model is provided.展开更多
A series of Sr1-1.5xYxTiO3（x = 0-12） solid solutions were synthesized by a solid state reaction process.The effects of reaction temperature and dopant on the crystallinity,microstructure and morphology of Sr1-1.5xYx...A series of Sr1-1.5xYxTiO3（x = 0-12） solid solutions were synthesized by a solid state reaction process.The effects of reaction temperature and dopant on the crystallinity,microstructure and morphology of Sr1-1.5xYxTiO3（x=0-0.12） were investigated.Pure and single-phase perovskite-type Sr1-1.5xYxTiO3（x0.08） solid solutions were obtained at 1 400 ℃ for 6 h.The perovskite-type SrTiO3 and pyrochlore-phase Y2Ti2O7 coexisted for x = 0.08-0.12,leading to an unstable and unfavourable solid solution structure for long-term immobilization of the 90Sr.The X-ray diffraction patterns for Rietveld refinement analysis confirmed the formation of a Sr1-1.5xYxTiO3（x = 0-0.12） continuous solid solution.Stretching and bending vibrations were assigned in the infrared region.The SrTiO3 grain size increased with Y content.The leaching behavior of Y^3＋ from the waste forms of Sr1-1.5xYxTiO3 was controlled by its structural change.展开更多
基金jointly sponsored by the Key Project of the Chinese National Programs for Fundamental Research and Development ("973 Program" Grant No.2013CB430106)+1 种基金the Key Project of the Chinese National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (Grant No.2012BAC22B01)the National Natural Science Foundation of China ( Grant No.41375108)
文摘ABSTRACT The Global/Regional Assimilation and PrEdiction System （GRAPES） is the newgeneration numerical weather predic- tion （NWP） system developed by the China Meteorological Administration. It is a fully compressible non-hydrostatical global/regional unified model that uses a traditional semi-Lagrangian advection scheme with cubic Lagrangian interpola tion （referred to as the SL_CL scheme）. The SL_CL scheme has been used in many operational NWP models, but there are still some deficiencies, such as the damping effects due to the interpolation and the relatively low accuracy. Based on Reich＇s semi-Lagrangian advection scheme （referred to as the R2007 scheme）, the Re_R2007 scheme that uses the low- and high-order B-spline function for interpolation at the departure point, is developed in this paper. One- and two-dimensional idealized tests in the rectangular coordinate system with uniform grid cells were conducted to compare the Re..R2007 scheme and the SL_CL scheme. The numerical results showed that： （1） the damping effects were remarkably reduced with the Re_R2007 scheme; and （2） the normalized errors of the Re_R2007 scheme were about 7.5 and 3 times smaller than those of the SL_CL scheme in one- and two-dimensional tests, respectively, indicating the higher accuracy of the Re..R2007 scheme. Furthermore, two solid-body rotation tests were conducted in the latitude-longitude spherical coordinate system with non uniform grid cells, which also verified the Re_R2007 scheme＇s advantages. Finally, in comparison with other global advection schemes, the Re_R2007 scheme was competitive in terms of accuracy and flow independence. An encouraging possibility for the application of the Re_R2007 scheme to the GRAPES model is provided.
基金Funded by the National Natural Science Foundation of China(No.21501159)
文摘A series of Sr1-1.5xYxTiO3（x = 0-12） solid solutions were synthesized by a solid state reaction process.The effects of reaction temperature and dopant on the crystallinity,microstructure and morphology of Sr1-1.5xYxTiO3（x=0-0.12） were investigated.Pure and single-phase perovskite-type Sr1-1.5xYxTiO3（x0.08） solid solutions were obtained at 1 400 ℃ for 6 h.The perovskite-type SrTiO3 and pyrochlore-phase Y2Ti2O7 coexisted for x = 0.08-0.12,leading to an unstable and unfavourable solid solution structure for long-term immobilization of the 90Sr.The X-ray diffraction patterns for Rietveld refinement analysis confirmed the formation of a Sr1-1.5xYxTiO3（x = 0-0.12） continuous solid solution.Stretching and bending vibrations were assigned in the infrared region.The SrTiO3 grain size increased with Y content.The leaching behavior of Y^3＋ from the waste forms of Sr1-1.5xYxTiO3 was controlled by its structural change.
