基于实测数据的大气密度反演方法及应用研究

针对中长期的平均大气密度反演问题,以我国典型遥感卫星运行轨道数据作为基础,采用实测数据反演大气密度并对MSIS00模型进行局部修正,并将修正后的模型应用于遥感卫星推进剂的预算,仿真结果表明:得到的修正大气模型具有较高的准确度,且采用修正后的大气模型得到的轨道维持推进剂消耗比修正前减少了近35%,达到了在保障卫星安全运行基础上最大限度降低整星质量的目的。研究结果还可用于我国未来航天器的高精度轨道预报、推进剂预算、碰撞规避等任务。

太阳系边际探测飞行任务规划

针对太阳系边际探测任务,开展了星际多目标飞越的任务规划,采用小推力混合优化设计方法完成了基于借力飞行及电推进技术的行星际转移轨道联合优化设计,对比研究了面向日球层鼻尖和尾部探测的星际多目标探测飞行方案。研究表明,探测器在2024-2025年发射,可飞抵日球层鼻尖区域,在2027-2030年发射可飞抵日球层尾部区域,并可在2049年1月1日前飞离日心100 AU,实现太阳系边际空间的科学探测。其中日球层鼻尖探测任务探测器飞抵100 AU的位置位于鼻尖中心区域,可与旅行者1号、2号探测器形成有效互补。文章所用任务规划方法,可为太阳系边际探测的自主任务规划技术提供基础,相关研究成果能够为未来中国首次太阳系边际探测任务的实施提供有价值的参考。

多次行星借力的小推力飞行控制策略研究

针对小推力深空探测器采用多次行星借力的飞行控制策略优化问题,文章提出了一种将推进段作为整体与滑行段进行打靶拼接的方法,最大限度地减少了优化设计时的待优化参数个数.首先,文章给出了小推力飞行轨道的间接优化设计模型和基于B平面理论的行星借力模型.随后,建立了给定开关机时序条件下的小推力借力飞行控制策略优化模型;最后,采用遗传算法和序列二次规划算法循环对该模型进行优化求解,并以地球–金星–地球–木星小推力飞行轨道控制策略优化设计为例进行仿真分析,仿真结果验证了优化模型的正确性和有效性,表明本文的研究方法可对小推力多次行星借力飞行的控制策略进行优化设计.

多源异构大数据下支持范围密文搜索属性加密

目前的数据加密方法在对数据进行加密时,没有对数据进行过滤,导致全局数据初始化时间、数据加密时间以及对加密后的密文数据搜索时间较长。提出基于多源异构大数据下支持范围密文搜索属性加密方法,对数据进行过滤,通过建立密钥池,对数据进行聚合操作完成水印的添加,采用小波变换实现数据的过滤,进而缩小了数据范围,通过密文搜索属性加密方法对全局数据、授权中心进行初始化,生成用户私钥,然后对全局数据进行加密,生成对应陷门,完成对密文的搜索以及后期对用户属性的撤销,从而实现数据的加密以及对加密后的数据进行访问与搜索。实验结果表明,所提方法的全局数据初始化时间、数据加密时间以及密文搜索时间的开销结果均较为理想,可以对数据完成加密,并且保证安全前提下完成对密文的搜索。

夹心型磷钨酸盐光催化降解甲基橙

光催化降解有机污染物具有降解效率高、矿化彻底等优点而备受关注,而组成丰富、结构多样的过渡金属夹心型磷钨酸盐光催化降解有机染料仍鲜有报道。本文通过水溶液合成法制备了一系列过渡金属二夹心磷钨酸盐Na_(2)M_(2)(PW_(9)O_(34))_(2)^(12-)(M=Mn^(2+),Co^(2+),Ni^(2+),Cu^(2+),Zn^(2+)),并利用粉末X射线衍射(P-XRD)、拉曼光谱(Raman)、红外光谱(IR)对夹心型磷钨酸盐的结构进行表征,利用紫外-可见光谱(UV-Vis)、循环伏安法(CVs)对夹心型磷钨酸盐的光、电活性进行研究。以甲基橙为光催化降解底物分子,考察不同过渡金属二夹心磷钨酸盐、催化剂用量、底物分子浓度对甲基橙光催化降解率的影响。五种过渡金属二夹心磷钨酸盐催化剂对甲基橙光催化降解活性顺序为:Na_(2)Co_(2)(PW_(9)O_(34))_(2)^(12-)>Na_(2)Zn(2)(PW_(9)O_(34))_(2)^(12-)>Na_(2)Ni_(2)(PW_(9)O_(34))_(2)^(12-)>Na_(2)Mn_(2)_(2)(PW_(9)O_(34))_(2)^(12-)>Na_(2)Cu_(2)(PW_(9)O_(34))_(2)^(12-)。

Design and Development of System Platform of "Study on Relationship between Natural Phenology and Climate Change" Based on WEB and GIS

[Objective] The research aimed to study design and development of system platform of 'study on relationship between natural phenology and climate change' based on WEB and GIS. [Method] Relied on the technologies of WEB and GIS, a set of system platform of 'study on relationship between natural phenology and climate change' was developed based on the hybrid architecture of C/S (Client/Server) and B/S (Browser/Server). Moreover, its establishing process and functional module were detailedly introduced. [Result] The natural phenology and climate change in Guangxi were research objects of system platform of 'study on relationship between natural phenology and climate change'. By combining WEB and GIS with database, the primary application of 'study on relationship between natural phenology and climate change' was realized. The system used hybrid architecture of C/S and B/S. The four-layer architectures were independent to improve security, stability and maintainability of system. The visual interface on the foreground was simply, clear and easy to use. The generating program of GIS three-dimensional graph on the background was real-time and high-efficiency, providing powerful guarantee for stable and safe operation of phenology research work process. The system had functions of inquiry, analysis, statistical diagram, GIS three-dimensional graph and data export. Through the analysis of natural phenology observation data, the system could find variation rule of natural phenology as three-dimensional space (longitude, latitude and altitude) and its relationship with climate change. [Conclusion] The research laid good foundation for further deeply carrying out application of 'study on relationship between natural phenology and climate change', and also provided reference basis for recognizing nature and using change rule of phenology to execute production scheduling and strategic decision (seed-introduction and regionalization).

Ω-左R-模范畴中内射对象的等价刻画

引入内射Ω-左R-模的概念,研究内射Ω-左R-模的等价刻画,证明一簇Ω-左R-模的乘积是内射Ω-左R-模当且仅当每一个是内射Ω-左R-模,一个Ω-左R-模是内射Ω-左R-模当且仅当它的每一个截集是内射左R-模.