Mercury’s Atmosphere: A Surface-Bounded Exosphere

The existence of a surface-bounded exosphere about Mercury was discovered through the Mariner 10 airglow and occultation experiments. Most of what is currently known or understood about this very tenuous atmosphere, however, comes from ground-based telescopic observations. It is likely that only a subset of the exospheric constituents have been identified, but their variable abundance with location, time, and space weather events demonstrate that Mercury’s exosphere is part of a complex system involving the planet’s surface, magnetosphere, and the surrounding space environment (the solar wind and interplanetary magnetic field). This paper reviews the current hypotheses and supporting observations concerning the processes that form and support the exosphere. The outstanding questions and issues regarding Mercury’s exosphere stem from our current lack of knowledge concerning the surface composition, the magnetic field behavior within the local space environment, and the character of the local space environment.     

诱导创新理论与我国农业技术创新方向

由于在技术变迁过程中会出现“路径依赖”现象，技术创新方向的选择就显得至关重要。当前我国应发展劳动力使用型技术，但从长远来看必须走知识农业的道路；丰裕型农产品应成为农业技术创新的主导方向；政府要制定良好的教育、科研推广制度，促进技术创新方向合理化。     

计算物理中的数学实验方法

论述了计算物理与数学实验的关系,以及数学实验对计算物理的重要性,并通过实例说明,利用数学实验方法可以简化计算,突出物理概念,使问题得到更好的解决。     

知识、经验的表达及在概念设计中的应用

介绍了如何针对知识在概念设计中的不同层次对知识进行分类、建立知识经验库 ;阐述了知识、经验在概念设计中的应用 ,以达到提高设计质量、缩短设计周期的目的     

Progress on Solar Physics Research in China

The progress on Chinese Space Solar Telescope (SST) in 2002-2004 is introduced. The documentations on plans and outlines based on the standards of Chinese aerospace industry for SST mission has been fulfilled. The key technical problems of SST satellite platform and payloads are tackled during pre-study stage of the mission. The laboratory assembly and calibration of the main optical telescope of 1.2 m spherical mirror and 1 m plain mirror have been carried out with the accuracy of λ/40 and λ/30, respectively. The prototype at 17.1 nm for extreme ultraviolet telescope is under development and manufacture with a diameter of 13 cm. Its primary and secondary mirrors have a manufacturing error of 5 nm with a roughness degree of less than 0.5 nm and a multiplayer reflection factor of better than 20%. The on-board scientific data processing unit has been developed. Prototypes for other payloads such as H. and white light telescope, wide band spectroscopy in high energy and solar and interplanetary radio spectrometer have been developed accordingly.     

Progress on Microgravity Sciences in China

The main progress of the research activities on microgravity fluid physics, combustion, biotechnology research and fundamental Physics in China are briefly summarized in the present paper. The major space missions and experimental results obtained on board the Chinese recoverable/nonrecoverable satellites and the Chinese manned spaceship named "Shen Zhou" are presented summarily. The recent main activities of the ground-based studies in China are introduced in brief.     

基于CBR的数控设备故障诊断系统知识表示

随着数控设备越来越复杂,对设备故障诊断与维修提出了更高的要求,采用专家系统的方式建立故障诊断系统以实现数控设备的快速诊断和维修.针对CBR (Case-Based Reasoning)系统自身的增量学习模式使系统的实例库逐渐增大,系统效能大大降低的缺点.根据数控系统结构的特点采用分层检索的方法,依据该检索方法采用框架型的知识表示方式,提高了大实例库的检索效率.将该方法应用于数控设备的故障诊断系统中,提高了故障诊断的诊断效率.      

应用于工程设计的KBE技术

介绍了一种新型的工程设计方法——基于知识的工程(knowledge—Based Engineering,KBE),并对这一新型设计系统的研究和应用现状、关键技术(知识获取,知识表示和推理,知识库的建立)、应用过程中存在的问题以及将来的发展趋势作了分析和介绍。     

Shoemaker－Levy9彗星撞击木星的流星物理学

本文从流星物理学的基本方程出发,导出Shoemaker-Levy9慧星撞击木星时的速度、质量损失、电子线密度、能量释放率随高度的分布公式;采用合理的参数,作了一系列计算,并与观测资料比较,进行一些讨论。      

基于开放式知识表示的智能化产品设计

基于知识的智能化产品设计是CAD技术的发展方向之一,但现有知识表示方式缺乏对产品设计人员的开放性,不利于设计人员理解和维护设计系统中的知识。针对这一不足,研究机械产品设计领域常见的公式、表格、二维映射图、过程、规则等类型知识的开放式表示方法,给出了其BNF(Backus Naur Form)范式描述,并研究了各类知识的推理方法。所研究的开放式知识表示及相应推理方法具有以下优点:1)知识不再固化于设计系统;2)知识便于设计人员自行录入和维护。最后以基于知识的航空发动机涡轮叶片气膜孔设计为例,验证了该方法应用于工程实践的可行性。