Prospects in the orbital and rotational dynamics of the Moon with the advent of sub-centimeter lunar laser ranging

Lunar laser ranging (LLR) measurements are crucial for advanced exploration of the laws of fundamental gravitational physics and geophysics as well as for future human and robotic missions to the Moon. The corner-cube reflectors (CCR) currently on the Moon require no power and still work perfectly since their installation during the project Apollo era. Current LLR technology allows us to measure distances to the Moon with a precision approaching 1 mm. As NASA pursues the vision of taking humans back to the Moon, new, more precise laser ranging applications will be demanded, including continuous tracking from more sites on Earth, placing new CCR arrays on the Moon, and possibly installing other devices such as transponders, etc. for multiple scientific and technical purposes. Since this effort involves humans in space, then in all situations the accuracy, fidelity, and robustness of the measurements, their adequate interpretation, and any products based on them, are of utmost importance. Successful achievement of this goal strongly demands further significant improvement of the theoretical model of the orbital and rotational dynamics of the Earth–Moon system. This model should inevitably be based on the theory of general relativity, fully incorporate the relevant geophysical processes, lunar librations, tides, and should rely upon the most recent standards and recommendations of the IAU for data analysis. This paper discusses methods and problems in developing such a mathematical model. The model will take into account all the classical and relativistic effects in the orbital and rotational motion of the Moon and Earth at the sub-centimeter level. The model is supposed to be implemented as a part of the computer code underlying NASA Goddard’s orbital analysis and geophysical parameter estimation package GEODYN and the ephemeris package PMOE 2003 of the Purple Mountain Observatory. The new model will allow us to navigate a spacecraft precisely to a location on the Moon. It will also greatly improve our understanding of the structure of the lunar interior and the nature of the physical interaction at the core–mantle interface layer. The new theory and upcoming millimeter LLR will give us the means to perform one of the most precise fundamental tests of general relativity in the solar system.     

对接机构真空热试验外热流模拟方案研究

根据对接机构的结构特点和真空热试验要求,提出了红外笼、电加热片,以及红外笼+加热片组合3种对接机构外热流模拟方案.仿真计算了在真空罐模拟环境中各方案对接机构构件的稳态温度分布,并与轨道环境进行了比较.确定了最大温差构件.结果表明:红外笼方案较简单,适于正样飞行产品;电加热片和红外茏+加热片方案的地面模拟准确性较佳,适于初样地面产品试验.     

某卫星真空热试验中一些新要求的解决措施

某卫星在进行真空热试验时,对热流提出了三个方面的新要求：(1)对某些热流要求较低的加热区的加热笼进行修改,提高其低热流实现能力;(2)减小支架漏热;(3)实时计算设计热流和实际热流的周期积分偏差。由于修改时的约束条件较多,新的要求的满足非常困难。经过努力,最终解决了这些问题,通过对某些加热笼采取加热带双面涂黑漆的方法,实现了低热流;经过计算和针对性的设计,支架漏热不超过0．1188W;同时实现了设计热流与实际热流周期积分偏差的实时计算。     

航空发动机总体性能数学模型的1种收敛算法

介绍了改进的Newton-Raphson方法和Bmyden方法,以之计算航空发动机数学模型的收敛,提高了模型的收敛性。     

Analysis of the Boeing 747-100 using CEASIOM

One of the requirements for the SimSAC project was to use existing aircraft to act as benchmarks for comparison with CEASIOM generated models. Within this paper, results are given for one of these examples, the Boeing 747-100. This aircraft was selected because a complete dataset exists in the open domain, which can be used to validate SimSAC generated data. The purpose of this paper is to both give confidence in, and to demonstrate the capabilities of, the CEASIOM environment when used for preliminary aircraft and control system design. CEASIOM is the result of the integration of a set of sophisticated tools by the European Union funded, Framework 6 SimSAC program. The first part of this paper presents a comparison of the aerodynamic results for each of the solvers available within CEASIOM together with data from the 747-100 model published by NASA. The resulting nonlinear model is then trimmed and analysed using the Flight Control System Designer Toolkit (FCSDT) module. In the final section of the paper a state-feedback controller is designed within CEASIOM in order to modify the longitudinal dynamics of the aircraft. The open and closed loop models are subsequently evaluated with selected failed aerodynamic surfaces and for the case of a single failed engine. Through these results, the CEASIOM software suite is shown to be able to generate excellent quality adaptive-fidelity aerodynamic data. This data is contained within a full nonlinear aircraft model to which linear analysis and control system design can be easily applied.     

数理统计在机载设备延寿中的应用

介绍了利用数理统计分析开展机载设备寿命分布和故障水平研究的常用方法和步骤，并结合某型多功能显示器的延寿进行了应用分析。     

基于聚类分析的长沙市民体育休闲行为意向分异研究

城市居民作为体育休闲市场的主体,对其行为意向展开研究,对于发现城市体育休闲市场一般特征、开拓相关体育休闲市场等具有重要意义。通过对长沙市民抽样调查得到基础数据,运用聚类法得出3类意向不同的细分市场,采用对应分析方法对各细分市场的体育休闲意向进行分析,得出不同类型的细分市场的体育休闲意向有显著差异的结论,因而获得了体育休闲市场营销的启示。     

新城镇化背景下实现大遗址保护的对策

大遗址是一类与城镇建设与社会发展紧密相关的文化遗产资源,城镇化建设的指导方向直接影响着大遗址保护的策略.当前,大遗址保护工作在城镇化建设的热潮中机遇与挑战并存.新型城镇化概念的提出为大遗址保护提供了新的思路,它不再仅仅关注城镇化的速度和规模,更是肯定了城市的文化内涵和品格塑造,这有利于大遗址资源在城市改造进程中免遭破坏,进而转化为城市发展的助推力.当前,考古遗址公园建设是政府为文化遗产保护投入找到的一种回馈社会的最佳方式,也是化解遗址保护与城镇建设之间矛盾的最佳途径.郑州商城遗址已对此进行了多年有益的尝试,以此为例,对如何在新城镇化背景下做好遗址保护工作进行一些探索.     

Д-30发动机导向器叶片柱销孔的钎焊修复

针对Д-30发动机运行过程中,导向器叶片柱销孔出现扩大的情况,进行了钎焊工艺试验和实际叶片柱销孔的试焊修复,并制定了相应的钎焊修复工艺流程。     

贫困大学生的自助与"他助"

大学贫困生不仅数量越来越多，而且他们的生活状况也不容乐观，国家、社会和高校分别采取了各种措施以缓解贫困生的困难。但是，任何的减贫方式若没有贫困生主体的参与和实践，就不可能取得显著的成效。我们有必要换一个思路来仔细地探讨在缓解贫困这一问题上如何把贫困生的自助与社会性的“他助”更好地结合起来。