This review summarizes the general developments of the operational mesoscale model system based on the Global/Regional Assimilation and Prediction System-Tropical Monsoon Model (GRAPES-TMM) at the Guangzhou Regional M...This review summarizes the general developments of the operational mesoscale model system based on the Global/Regional Assimilation and Prediction System-Tropical Monsoon Model (GRAPES-TMM) at the Guangzhou Regional Meteorological Center. GRAPES-TMM consists of the Tropical Regional Atmospheric Model System for the South China Sea (TRAMS, a typhoon model with a horizontal resolution of 9 km), the Mesoscale Atmospheric Regional Model System (MARS, 3km) and the fine-scale Rapid Update Cycling (RUC, 1km) forecasting system. The main advances of model dynamical core and physical processes are summarized, including the development of the 3D reference atmosphere scheme, the coupling scheme between dynamics and model physics, the calculation of nonlinear terms by fractional steps, the gravity wave drag scheme induced by sub-grid orography and a simplified model for landsurface scheme. The progress of model applications is reviewed and evaluated. The results show that the updated 9-3-1forecasting system provides an overall improved performance on the weather forecasting in south China, especially for typhoon-genesis and typhoon-track forecasting as well as short-range weather forecasting. Capabilities and limitations as well as the future development of the forecasting system are also discussed.展开更多
In this paper, in-situ coagulation of 0.9Al_2O_3–0.1TiO_2 suspension and microwave dielectric properties of 0.9Al_2O_3–0.1TiO_2 ceramics prepared by a novel direct coagulation casting via high valence counter ions(D...In this paper, in-situ coagulation of 0.9Al_2O_3–0.1TiO_2 suspension and microwave dielectric properties of 0.9Al_2O_3–0.1TiO_2 ceramics prepared by a novel direct coagulation casting via high valence counter ions(DCC-HVCI) method were proposed. The 0.9Al_2O_3–0.1TiO_2 suspension could be coagulated via controlled release of calcium ions from calcium iodate at an elevated temperature. The influence of tri-ammonium citrate(TAC) content, solid loading, and calcium iodate content on the rheological properties of the suspension was investigated. In addition, the influence of coagulation temperature on coagulation time and properties of green bodies was also studied. It was found that the stable 0.9Al_2O_3–0.1TiO_2 suspension could be successfully prepared by adding 0.3 wt% TAC and adjusting pH value to 10–12 at room temperature. 0.9Al_2O_3–0.1TiO_2 green bodies with uniform microstructures were coagulated by adding 8.0 g/L calcium iodate after treating at 70 ℃ for 1 h. 0.9Al_2O_3–0.1TiO_2 ceramics, sintered at 1500 ℃ for 4 h and annealed at 1100 ℃ for 5 h, showed uniform microstructures with density of 3.62±0.02 g/cm^3. The microwave dielectric properties of 0.9Al_2O_3–0.1TiO_2 ceramics prepared by DCC-HVCI method were: ε_r = 11.26±0.06, Q×f = 11569± 629 GHz, τ_t = 0.93±0.60 ppm/℃. The DCC-HVCI method is a novel and promising route without binder removal process to prepare complex-shaped microwave dielectric ceramics with uniform microstructures and good microwave dielectric properties.展开更多
基金National Key R&D Program of China(2018YFC1506901)National Natural Science Foundation of China (41505084)Program of Science and Technology Department of Guangdong Province (201804020038)。
文摘This review summarizes the general developments of the operational mesoscale model system based on the Global/Regional Assimilation and Prediction System-Tropical Monsoon Model (GRAPES-TMM) at the Guangzhou Regional Meteorological Center. GRAPES-TMM consists of the Tropical Regional Atmospheric Model System for the South China Sea (TRAMS, a typhoon model with a horizontal resolution of 9 km), the Mesoscale Atmospheric Regional Model System (MARS, 3km) and the fine-scale Rapid Update Cycling (RUC, 1km) forecasting system. The main advances of model dynamical core and physical processes are summarized, including the development of the 3D reference atmosphere scheme, the coupling scheme between dynamics and model physics, the calculation of nonlinear terms by fractional steps, the gravity wave drag scheme induced by sub-grid orography and a simplified model for landsurface scheme. The progress of model applications is reviewed and evaluated. The results show that the updated 9-3-1forecasting system provides an overall improved performance on the weather forecasting in south China, especially for typhoon-genesis and typhoon-track forecasting as well as short-range weather forecasting. Capabilities and limitations as well as the future development of the forecasting system are also discussed.
基金supported by National Natural Science Foundation of China(No.51501066)China Postdoctoral Science Foundation(Nos.2015M572136,2017T100550,and 2016M602290)the Fundamental Research Funds for the Central University(No.2017JYCXJJ002)
文摘In this paper, in-situ coagulation of 0.9Al_2O_3–0.1TiO_2 suspension and microwave dielectric properties of 0.9Al_2O_3–0.1TiO_2 ceramics prepared by a novel direct coagulation casting via high valence counter ions(DCC-HVCI) method were proposed. The 0.9Al_2O_3–0.1TiO_2 suspension could be coagulated via controlled release of calcium ions from calcium iodate at an elevated temperature. The influence of tri-ammonium citrate(TAC) content, solid loading, and calcium iodate content on the rheological properties of the suspension was investigated. In addition, the influence of coagulation temperature on coagulation time and properties of green bodies was also studied. It was found that the stable 0.9Al_2O_3–0.1TiO_2 suspension could be successfully prepared by adding 0.3 wt% TAC and adjusting pH value to 10–12 at room temperature. 0.9Al_2O_3–0.1TiO_2 green bodies with uniform microstructures were coagulated by adding 8.0 g/L calcium iodate after treating at 70 ℃ for 1 h. 0.9Al_2O_3–0.1TiO_2 ceramics, sintered at 1500 ℃ for 4 h and annealed at 1100 ℃ for 5 h, showed uniform microstructures with density of 3.62±0.02 g/cm^3. The microwave dielectric properties of 0.9Al_2O_3–0.1TiO_2 ceramics prepared by DCC-HVCI method were: ε_r = 11.26±0.06, Q×f = 11569± 629 GHz, τ_t = 0.93±0.60 ppm/℃. The DCC-HVCI method is a novel and promising route without binder removal process to prepare complex-shaped microwave dielectric ceramics with uniform microstructures and good microwave dielectric properties.
