基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件...基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件束波转换效率30%。在强流电子束加速器平台上进行实验研究,当二极管电压500k V、电流6.2k A、引导磁场强度0.46T时,得到频率为9.40GHz、功率为900MW、脉宽为32ns的微波输出。该实验结果为低磁场器件实现高功率、高效率微波输出及永磁包装打下了良好的基础。展开更多
Nitrogen fertilizer is an important factor for crop production. The N application strategies named as former nitrogen moved backward( FNMB) are tested in three ecological regions to optimize the N application in rice....Nitrogen fertilizer is an important factor for crop production. The N application strategies named as former nitrogen moved backward( FNMB) are tested in three ecological regions to optimize the N application in rice. The dry matter accumulation and distribution,yield and quality are studied to understand the formation of yield and quality of rice under different N application strategies. The result indicates that former nitrogen moved backward( FNMB) can increase tiller number and dry matter accumulation; effective ears and yield can be increased with the increase of fertilization; rational nitrogen application can help to establish scientific group structure,harmonize yield component,and then achieve high ratio of input to output and benefit.展开更多
文摘基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件束波转换效率30%。在强流电子束加速器平台上进行实验研究,当二极管电压500k V、电流6.2k A、引导磁场强度0.46T时,得到频率为9.40GHz、功率为900MW、脉宽为32ns的微波输出。该实验结果为低磁场器件实现高功率、高效率微波输出及永磁包装打下了良好的基础。
文摘Nitrogen fertilizer is an important factor for crop production. The N application strategies named as former nitrogen moved backward( FNMB) are tested in three ecological regions to optimize the N application in rice. The dry matter accumulation and distribution,yield and quality are studied to understand the formation of yield and quality of rice under different N application strategies. The result indicates that former nitrogen moved backward( FNMB) can increase tiller number and dry matter accumulation; effective ears and yield can be increased with the increase of fertilization; rational nitrogen application can help to establish scientific group structure,harmonize yield component,and then achieve high ratio of input to output and benefit.