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11.
三维回转器回旋条件下拟南芥种子发育分析   总被引:1,自引:1,他引:0  
向重力性反应是植物适应地球重力环境的一个重要生理过程, 是植物正常生长发育不可缺少的反应机制, 但是, 微重力是否影响植物种子发育至今尚无一致性结论. 本文研究了三维回转器回旋模拟微重力对拟南芥种子发育(胚胎发育与代谢活动)的影响. 研究结果表明, 三维回转条件下, 拟南芥果荚出现不规则弯曲或扭曲形态, 形成的种子中可溶性糖和淀粉含量明显增加, 盐溶性贮藏蛋白质含量显著降低而碱溶性蛋白质含量显著升高, 球形胚时期的种子对三维回转处理最为敏感. 对球形胚时期的植株进行短期的三维回转处理可抑制胚柄细胞的分裂和伸长, 而胚柄伸长受阻可能会影响到营养物质向胚胎中输送, 进而导致部分胚胎败育. 对种子干燥脱水阶段的植株进行三维回转处理不影响胚胎的发育, 但会导致种子贮藏蛋白质含量下降.   相似文献   
12.
电刺激大壁虎中脑对运动行为影响的研究   总被引:1,自引:0,他引:1  
采用金属微电极对麻醉状态下的大壁虎(Gekko gecko)中脑脑区逐点施以电刺激,观测大壁虎中脑与运动的相互关系。结果发现,电刺激中脑不同脑区可分别诱导出张嘴、鸣叫及一些肢体动作,如:四肢动,脊柱对侧弯曲,脊柱同侧弯曲和脊柱S形弯曲等。这些结果为人工制导大壁虎运动打下一定的基础。  相似文献   
13.
本文利用SMM1980年和1984年观测的两组日冕物质抛射事件(CMF)及同期耀斑和爆发日珥观测资料,从速度、位置及活动相关率三个方面分析CME在这两个不同时期的特征,并由此推测它在整个太阳活动周内的变化趋势.   相似文献   
14.
本文对第22太阳周极大时期Imp≥M1.0X射线耀斑的空间分布进行了统计分析.结果表明,该事件存在南北半球分布的不对称性,且不对称性在极大年或其后一年改变符号.文中还对不对称性与太阳活动的相关关系也进行了探讨.   相似文献   
15.
Results of a statistical variation of total ion density observed in the vicinity of epicenters as well as around magnetically conjugated points of earthquakes are presented in this paper. Two data sets are used: the ion density measured by DEMETER during about 6.5?years and the list of strong earthquakes (MW?≥?4.8) occurring globally during this period (14,764 earthquakes in total). First of all, ionospheric perturbations with 23–120?s observation time corresponding to spatial scales of 160–840?km are automatically detected by a software (64,287 anomalies in total). Second, it is checked if a perturbation could be associated either with the epicenter of an earthquake or with its magnetically conjugated point (distance?<?1500?km and time?<?15?days before the earthquake). The index Kp?<?3 is also considered in order to reduce the effect of the geomagnetic activity on the ionosphere during this period. The results show that it is possible to detect variations of the ionospheric parameters above the epicenter areas as well as above their conjugated points. About one third of the earthquakes are detected with ionospheric influence on both sides of the Earth. There is a trend showing that the perturbation length increases as the magnitude of the detected EQs but it is more obvious for large magnitude. The probability that a perturbation appears is higher on the day of the earthquake and then gradually decreases when the time before the earthquake increases. The spatial distribution of perturbations shows that the probability of perturbations appearing southeast of the epicenter before an earthquake is a little bit higher and that there is an obvious trend because perturbations appear west of the conjugated point of an earthquake.  相似文献   
16.
掌握舱外维修维护的地面验证技术对长寿命载人航天器的研制和在轨运行十分重要,而建立一套舱外在轨维修维护地面验证平台是实现地面验证技术的基础。文章从航天器舱外维修维护地面验证平台的需求分析,任务和功能分配,系统组成,详细设计等几个方面系统阐述了平台的设计。集成测试结果表明,该平台满足航天器舱外维修验证需求,可以作为广泛使用的水槽和仿真手段的有效补充。  相似文献   
17.
本文拟对女大学生这一特殊的群体为研究对象,采用"运动套餐"实验法,结合问卷调查、文献资料法等,以《学生体质健康标准》为衡量标准,对其身体形态等方面产生的影响进行对照实验性的研究。经过十二周女大学生运用"运动套餐"课外体育活动实验,实验结果:实验组除体重指标以外呈现显著良性差异,实验组体重指数(BMI)朝正常体重区域发展,对控制体重有较好的作用,而对照组超重区域出现增长现象;实验组SCL90心理症状量表测试各项因子均值指标皆低于对照组,并抑郁、偏执两项因子出现差异;锻炼态度量表实验组各项指标除主观分量表均值以外皆高于对照组。结论:运用"运动套餐"实验组锻炼效果好于学校惯例式课外体育活动学生体育锻炼的效果,同时为高校体育课其它项目选项班设计不同的课外体育"运动套餐"提供参考。  相似文献   
18.
Outer space activities have evolved significantly. While they were previously the exclusive domain of a restricted number of states, now thanks to technological advances and the easing of governmental restrictions, space activities are carried out on a much larger scale and involve subjects of both a governmental and non-governmental nature. Furthermore, the commercial uses of outer space are making space business increasingly profitable and attractive to potential investors. As the economic value of outer space activities, as well as the number of space actors grows, it is nearly inevitable that international disputes related to the use of outer space will occur. Until recently, international space law contained little dedicated machinery to settle international outer space-related disputes. This absence significantly weakened the applicability and enforceability of space law and contributed to a climate of uncertainty. In order to address these issues, the Permanent Court of Arbitration (PCA) adopted the Optional Rules for Arbitration of Disputes Relating to Outer Space Activities on 6 December 2011. The PCA Space Rules represent a significant development in the field of space law because they provide a voluntary and binding dispute settlement method accessible to all space actors and modeled on the specific legal and economic characteristics of space activities. This paper describes the genesis of the PCA Space Rules, assesses their content and innovative character, evaluates their possible implications for the settlement of outer space disputes, and argues that they should be positively received by the outer space community.  相似文献   
19.
Since the beginning space was an exclusive domain of public organizations, the role of privates is becoming more and more important, and not only in commercial activities. However, the main international treaties dealing with this subject are still based on the assumption that space activities are mostly reserved to states. In the last decade the idea that the role of privates could include the management of space infrastructures and launch vehicles gained support and now private launch services are a reality. An even wider role of privates is now advocated and private exploration and exploitation missions are discussed. This requires that space activity in general can generate an attractive return and those business models are identified.  相似文献   
20.
通过文献资料对我国高校开展武术活动的影响因素进行了探讨分析。研究发现大学生武术人口;学生认识水平;师资状况;经济和环境等因素对高校开展武术活动有一定的影响。提出了应从大学生认识观念、教师的引导作用、师资队伍建设、改进教学方法、实现"以人为本"的武术教学目标等方面入手进行强化建设。  相似文献   
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