To clarify the effects of mechanical sowing and transplanting on dry mat- ter production of middle-season hybrid rice, a two-factor split plot design was used to study the effects of different sowing and transplanting...To clarify the effects of mechanical sowing and transplanting on dry mat- ter production of middle-season hybrid rice, a two-factor split plot design was used to study the effects of different sowing and transplanting methods and their interac- tion with the seedling number per hill or seeding time on dry matter accumulation, distribution and transformation of F You 498, a middle-season hybrid rice variety, under field conditions in 2012 and 2013. The results showed that there was a marked effect of the sowing and transplanting methods and their interaction with the seedling number per hill or seeding time on dry matter accumulation, distribution and transformation. The total population dry matter accumulation of the treatments with mechanical direct seeding （MDS） and machine-based transplanting （MT） was lower than that of the treatment with traditional manual transplanting （TMT）. How- ever, MDS had higher dry matter accumulation and accumulating rate in the joint- ing-earing stage,and maintained higher stem-sheath exportation, export rate and transformation than MT and TMT; MT had higher dry matter accumulation and ac- cumulating rate in the heading-maturity period than MDS and TMT. Moreover, the treatments with low seedling number per hill or early seeding enhanced the assimi- lation of dry matter after heading,the ratio of dry matter accumulation after earing to biomass yield and the contribution rate of dry matter accumulation after earing, and a reasonable early sowing was favorable to increase the harvest index of middle- season hybrid rice under mechanical sowing and transplanting conditions.展开更多
A method based on the virtual prototype technology simulating the separation of a launch vehicle from its aircraft in the aircraft wake was proposed based on the internally carried air-launched launch vehicle program....A method based on the virtual prototype technology simulating the separation of a launch vehicle from its aircraft in the aircraft wake was proposed based on the internally carried air-launched launch vehicle program.In this method,the full-scale model of the aircraft,the vehicle and the parachute are constructed.Then,they are imported into the ADAMS software,constraint solutions and driving forces are then added for visual dynamic simulation.The unsteady aerodynamic forces of the vehicle in the aircraft wake are calculated by CFD and the moving grid technique.The forces generated by the parachute can be derived from the Kirchhoff motion equation.Through comparing and analyzing the simulation results under different launch conditions,it has been proven that this method simulates the separation of a launch vehicle from the aircraft in the aircraft wake accurately.It provides the foundation for the aggregate project of internally carried air-launch vehicles,and offers a new referenced method for multi-body dynamic simulation.展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201303129)National Science and Technology Project for Bump Crop(2011BAD16B05)Scientific Research Foundation of Sichuan Agricultural University~~
文摘To clarify the effects of mechanical sowing and transplanting on dry mat- ter production of middle-season hybrid rice, a two-factor split plot design was used to study the effects of different sowing and transplanting methods and their interac- tion with the seedling number per hill or seeding time on dry matter accumulation, distribution and transformation of F You 498, a middle-season hybrid rice variety, under field conditions in 2012 and 2013. The results showed that there was a marked effect of the sowing and transplanting methods and their interaction with the seedling number per hill or seeding time on dry matter accumulation, distribution and transformation. The total population dry matter accumulation of the treatments with mechanical direct seeding （MDS） and machine-based transplanting （MT） was lower than that of the treatment with traditional manual transplanting （TMT）. How- ever, MDS had higher dry matter accumulation and accumulating rate in the joint- ing-earing stage,and maintained higher stem-sheath exportation, export rate and transformation than MT and TMT; MT had higher dry matter accumulation and ac- cumulating rate in the heading-maturity period than MDS and TMT. Moreover, the treatments with low seedling number per hill or early seeding enhanced the assimi- lation of dry matter after heading,the ratio of dry matter accumulation after earing to biomass yield and the contribution rate of dry matter accumulation after earing, and a reasonable early sowing was favorable to increase the harvest index of middle- season hybrid rice under mechanical sowing and transplanting conditions.
基金Supported by the National Natural Science Foundation Programme of China(No.61374145)
文摘A method based on the virtual prototype technology simulating the separation of a launch vehicle from its aircraft in the aircraft wake was proposed based on the internally carried air-launched launch vehicle program.In this method,the full-scale model of the aircraft,the vehicle and the parachute are constructed.Then,they are imported into the ADAMS software,constraint solutions and driving forces are then added for visual dynamic simulation.The unsteady aerodynamic forces of the vehicle in the aircraft wake are calculated by CFD and the moving grid technique.The forces generated by the parachute can be derived from the Kirchhoff motion equation.Through comparing and analyzing the simulation results under different launch conditions,it has been proven that this method simulates the separation of a launch vehicle from the aircraft in the aircraft wake accurately.It provides the foundation for the aggregate project of internally carried air-launch vehicles,and offers a new referenced method for multi-body dynamic simulation.
