TROS-Ⅰ型流动人卫激光测距仪光学系统设计

介绍了车载流动型人卫激光测距仪光学系统(包括激光发射系统、接收系统及微光电视监视系统)的设计思想和方法,着重叙述了光学系统的结构设计、关键部件几何尺寸的确定及重要元器件的选取。设计基于流动型仪器应满足的防振、体积小、调校方便、抗环境干扰能力强等特点。多年的实测证明,这种光学系统不仅能满足流动型人卫激光测距仪总体设计要求,而且经济实用。     

Mapping models for near-conservative systems with applications

A systematic method is presented to construct a mapping model for a near-conservative system, based on that of Hadjidemetriou for a Hamiltonian system [1]. The mapping we constructed preserves the basic features of the actual system. We apply this method to the forced oscillating system and to the 3 : 1 resonant grain motion in the presence of Poynting-Robertson drag.Supported by the National Natural Science Foundation of China.     

Forced secondary resonances at the 3 : 1 commensurability

For the 3 : 1 Jovian resonance problem, the time scales of the two degrees of freedom of the resonant Hamiltonian are well-separated [5]. With the adiabatic approximation, the solution for the fast oscillations can be found in terms of the slowly varying variables. Thus the rapidly oscillating terms in the slow oscillation equations can be treated as forced terms. We refer to the resonance between the forcing and intrinsic frequencies as a forced secondary one in this paper. We discuss the forced secondary resonances in asteroidal motion at the 3 : 1 commensurability by using Wisdom's method. The results show that the orbits situated originally near the resonance will leave the neighbourhood of resonance and tend to the separatrices and critical points for different energies, respectively. We have not found any stochastic web as expected in this case. Moreover, we study the problem of validity on the approximation of a system.The Project Supported by the National Natural Science Foundation of China.     

近10年我国天体测量的发展

简述天体测量学研究的内各以及与各相关学科之间的关系；描述近10年来国际天体测量研究的进展和前沿课题；叙述我国天体测量研究的历史背景和研究基础，以及近10年来在国家自然科学基金委员会和其他科学组织支持下取得的成果，并对今后10～20年我国天体测量的发展提出初步看法。     

新参考系的引入对天体测量学的影响

由于观测、参考架、模型、时间尺度精度的不断提高和完善，国际天球参考系(ICRS)被引入使用，IAU2000年大会决定从2003年起采用新的天球中介极(CIP)、新的天球中介原点(CIO)、新的岁差一章动模型和新的UTI定义等，并定义了新的中介的运动参考架，由此给天体测量学带来很大的影响，天体测量学的内容和实践发生了许多重要的变化。据此，对天体测量学的术语、概念和定义的变化作了描述，并讨论了变化的原因和对天体测量学的影响。新的一套天体测量理论和方法正在变更之中，我们应及时跟上这个领域的发展步伐。     

天文学研究发展趋势分析--恒星与恒星系统

对在1981-2000年世界上所发表的和中国学者所发表的有关恒星与恒星系统的论文作统计发现：此期间世界上这一领域的发展较平稳，而我国的发展快速．这反映了改革开放后，我国基础学科研究大有进展．从各分支所占的比重和发展来看，我国在恒星与恒星系统的研究与世界同期有几乎相同的分布，因此总体上我国在这一领域的发展基本正常．当然有些分支发展较快，如有关超新星及其遗迹、星际介质和恒星形成区、化学丰度的研究等，这和一些较强的研究团组形成有关；在双星研究方面，我国则与世界发展一致，双星研究始终是恒星研究领域的重点；而在世界范围内较突出的关于银河系的研究，在我国却相对较弱．恒星和恒星系统这一研究领域20年的论文数统计显示，我国学者所发表的论文只占世界总论文数的1．3％，虽然在最后5年有大幅上升，但也只占2．0％，这与我国IAU会员数所占比例相比是偏少的．就世界整体而言，恒星领域的研究进展与整个天文学领域相比是较慢的，显然这与一批能做深空探测和高能波段观测的设备投入有关．因此，除了对恒星及恒星系统领域作统计分析外，对整个天文学领域各大分支作分析可能对制定今后我国天文学发展计划更有利。     

用LLR资料解算日月轨道根数

本文推导了激光测月资料归算中测距对地月系轨道根数的偏导数，并对所得偏导数进行了精度估计，利用这些偏导数和１９８８年至１９９２年全球激光测月资料解算了日月轨道根数，得到了比较理想的结果。     

Preparing For Hyperseed MAC: An Observing Campaign To Monitor The Entry Of The Genesis Sample Return Capsule

The imminent return of the Genesis Sample Return Capsule (SRC) from the Earth’s L1 point on September 8, 2004, represents the first opportunity since the Apollo era to study the atmospheric entry of a meter-sized body at or above the Earth’s escape speed. Until now, reentry heating models are based on only one successful reentry with an instrumented vehicle at higher than escape speed, the 22 May 1965 NASA “FIRE 2” experiment. In preparation of an instrumented airborne and ground-based observing campaign, we examined the expected bolide radiation for the reentry of the Genesis SRC. We find that the expected emission spectrum consists mostly of blackbody emission from the SRC surface (T∼ ∼2630 K@peak heating), slightly skewed in shape because of a range of surface temperatures. At high enough spectral resolution, shock emission from nitrogen and oxygen atoms, as well as the first positive and first negative bands of N₂⁺, will stand out above this continuum. Carbon atom lines and the 389-nm CN band emission may also be detected, as well as the mid-IR 4.6-μm CO band. The ablation rate can be studied from the signature of trace sodium in the heat shield material, calibrated by the total amount of matter lost from the recovered shield. A pristine collection of the heat shield would also permit the sampling of products of ablation.     

银河系运动学参数的确定

利用 2 0 2个太阳附近疏散星团的视向速度和自行观测资料 ,对太阳的运动和银河系的运动学参数进行了研究。其中 ,距离在 0 .5kpc到 2kpc之间的 12 8个疏散星团对平均太阳运动分量的解算结果是 (u0 ,v0 ,w0 ) =(- 13.8± 1.4 ,- 5 .0± 1.6 ,- 11.6± 2 .9)km/s ;Oort常数和银河系径向运动参数的解算结果分别为 (A ,B) =(16 .9± 1.1,- 11.6± 2 .6 )km·s- 1·kpc- 1及 (C ,D) =(2 .5± 1.1,- 2 .1± 0 .9)km·s- 1·kpc- 1。