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A Controlled Ecological Life Support System (CELSS) is a sealed system used in spaceflight in order to provide astronauts with food and O2 by plants. It is of great significance to increase the energy-using efficiency because energy is extremely deficient in the space. Therefore, the objective of this research was to increase the energy-using efficiency of wheat by regulating the photoperiod. Sixteen treatments were set in total: four photoperiods before flowering (PBF) combined with four photoperiods after flowering (PAF) of 12 h, 16 h, 20 h and 24 h. The light source was red–blue LED (90% red+10% blue). As a result, the growth period of wheat was largely extended by shorter PBF, particularly the number of days from tillering to jointing and from jointing to heading. The period from flowering to maturity was extended by shorter PAF. Shorter PBF and longer PAF could increase not only the yield but also the energy-using efficiency of wheat. As for the nutritional quality, longer photoperiod (both PBF and PAF) increased starch concentration as well as decreased protein concentration of seeds. The effects of PBF and PAF were interactional. The lighting strategy with PBF of 12 h and PAF of 24 h was proved to be the optimum photoperiod for wheat cultivation in CELSS. The mechanisms of photoperiod effect contain two aspects. Firstly, photoperiod is a signal for many processes in plant growth, particularly the process of ear differentiation. Shorter PBF promoted the ear differentiation of wheat, increasing the spikelet number, floret number and seed number and thus enhancing the yield. Secondly, longer photoperiod leads to more light energy input and longer time of photosynthesis, so that longer PAF provided more photosynthate and increased seed yield. 相似文献
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大客机对中国的航空航天业是一个非常重要的项目.大客机项目所研制的飞机必须高效且有市场竞争力.而航空电子系统作为飞机系统的重要组成部分,必须为飞机的设计理念提供支持. 相似文献
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分区并行跨声速流的计算 总被引:2,自引:0,他引:2
本文采用求解N-S方程方法计算了轴对称钝头倒锥体外形的跨声速大迎角层流流动。 相似文献
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大型飞机机载设备及关键技术分析 总被引:1,自引:0,他引:1
机载设备已成为飞机实现新飞行功能、完成新任务的主要保证.机载设备是飞机的耳目、大脑和神经,可以说是飞机先进程度的一个重要标志,没有先进的机载设备就没有先进的飞机.其相关的关键技术也起着重大的作用. 相似文献
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在分析反辐射导弹末制导段特点的基础上,针对其跟踪模型不满足可观测性要求的问题,提出了一种基于方位/俯仰角的跟踪方案。理论分析和仿真验证了该方案具有较高的跟踪精度和实时性,并具有较好的通用性,为解决不可观测情况下的高精度稳定跟踪问题提供了一种新的思路。 相似文献
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Tao Yu Tian Mao Yungang Wang Zhongcao Zeng Chunliang Xia Fenglei Wu Le Wang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
With the rapid increase of GPS/GNSS receivers being deployed and operated in China, real-time GPS data from nearly a thousand sites are available at the National Center for Space Weather, China Meteorology Administration. However, it is challenging to generate a high-quality regional total electron content (TEC) map with the traditional two-dimensional (2-D) retrieval scheme because a large horizontal gradient has been reported over east–south Asia due to the northern equatorial ionization anomaly. We developed an Ionosphere Data Assimilation Analysis System (IDAAS), which is described in this study, using an International Reference Ionosphere (IRI) model as the background and applying a Kalman filter for updated observations. The IDAAS can reconstruct a three-dimensional ionosphere with the GPS slant TEC. The inverse slant TEC correlates well with observations both for GPS sites involved in the reconstruction and sites that are not involved. Based on the IDAAS, simulations were performed to investigate the deviation relative to the slant-to-vertical conversion (STV). The results indicate that the relative deviation induced by slant-to-vertical conversion may be significant in certain instances, and the deviation varies from 0% to 40% when the elevation decreases from 90° to 15°, while the relative IDAAS deviation is much smaller and varies from −5% to 15% without an elevation dependence. Compared with ‘true TEC’ map derived from the model, there is large difference in STV TEC map but no obvious discrepancy in IDAAS map. Generally, the IDAAS TEC map is much closer to the “true TEC” than is STV TEC map is. 相似文献