韩显符及其天文仪器研究

对北宋天文学家韩显符 (94 0～ 10 13)及其制造的天文仪器进行了研究 .韩显符首先制造了至道浑仪 ,他大胆简化 ,取消了白道环 ;在地平圈上首次设置“地盘平准轮” ,加强了仪器工作部分的水平调节 ;在“游规”中设计“二直矩”以夹窥管 ,使其运转平稳 ;他明确提到定天极高度的问题 ,为后世定天极的理论和方法的产生做了铺垫 .他的第二件天文仪器在授业与观测天象方面的功用 ,证明韩显符的天文学成就是多方面的 .另外 ,还对其天文仪器的发展和承继性问题做了初步探讨     

中国古代历法中内插法的应用与发展

运用历史文献分析和逻辑分析相结合的研究方法，对中国古代历法中内插法的产生、发展进行了系统的疏解和研究．结果表明，内插法肇始于《周髀算经》中关于晷长的计算，后经东汉、随、唐、元等朝代天文学家在日、月、五星的运行测量和计算中逐步得到发展．元代郭守敬的平立定三差法(招差法)标志看中国古代历法计算从二次到高次插值方法的演变．通过中外比较，有些成果比西方国家早400-1000年。     

Simultaneous measurements of thermal diffusivity, thermal conductivity and thermopower with application to copper and ceramic superconductors

A home made experimental set-up allows us to measure the thermal conductivity, the thermopower and the thermal diffusivity simultaneously in the temperature range (20-300 K). Therefore the specific heat can be deduced. The role of a radiation shield is shown to be relevant. Tests of the system are made on a 99.9% pure Cu sample and two polycrystalline cuprate ceramics for illustration. Without any complicated optimisation, the technique indicates much promise already due to its efficiency and rapidity. Received 9 November 1998 and Received in final form 12 July 1999     

我国天体物理研究50年进展

中国天体物理研究的发展在自建国以来的５０年中,经历了几乎是从头建设到发展成长的道路。其中历经“三年困难”、十年“文化大革命”的磨难,“文革”之后,改革开放的春风为天体物理开避了迅速发展的道路,在此期间,我国有计划地研制了一系列天文观测 天文和天体物理研究地实验条件,在此基础上,无论是天体物理的观测和理论研究都有了长足的发展,我国天体物理研究在国际上的影响也日益加强。这一切,为在新世纪中我国天体物理     

天文公共选修课教学的一点体会

讨论了天文公共选修课的教学特点,认为当前的天文选修课要有时代气息,即选修课教学要和科学研究紧密结合,要与其他学科相结合,教学手段要传统手段和现代手段相结合.     

“Chi-Fang-Qi”: Is it the aureole of an ancient supernova?

An annotation for the statement about JingXing (Great Star) in the most famous Chinese ancient historical book Ski Ji Historical Records authored by Sima Qian reads as follows: “There was a red aureole (“Chi-Fang-Qi”) which connected with a deep-color aureole (“Qing-Fang-Qi”). Two yellaw stars were in the red aureole,one yellow star was in the deep-color aureole”. The author of the annotation was Meng Kang, an officer as well as a scholar of the Wei State in the Three Kingdoms period. The same records are to be found in two other Chinese histurical books compiled by the authors of later ages in Tang Dynasty——Jin History and Sui History. The scene illustrated by the record of “Chi-Fang-Qi” is very similar to the pictures of SN1987A taken by the Hubble Space Telescope. Let it be noted that although the ancient authors were often with serious wrong understandings of some astronomical phenomena such as supernovae, their depictions about natural phenomena they witnessed were mostly objective, and it was unlikely that they fictionally made the record of “Chi-Fang-Qi”. We infer that the ancient observers might have ever watched a very bright supernnva with an aureole structure in its remnant and then left such a record. Meng Kang perhaps was the first to give the record about“Chi-Fang-Qi”, and he might have lived in the period from about AD 180 to AD250, very near to AD 185. so, here the supernova the ancient people watched was most likely the one in the year of AD 185. This supposition is consistent with the distance parameter of the most possible remnant of SN185 derived by some modern measurements. If the correlation between the record of “Chi-Fang-Qi” and the supernova remnant can he further proven true, it would be an important verification of the modern theory about stellar evolution.     

High-spin states in 190Pt

The level structure of 190Pt has been studied experimentally using the 176Yb (18O, 4n) reaction at beam energies of 88 and 95 MeV. γ-γ-t coincidence measurements were carried out. Based onthe analysis of γ-γ coincidence relationships, the level scheme of 190Pt is extended to high-spin states. A new structure built on the 3413.6 keV 14+ state has been observed, and the vi1-213/2 vh-19/2 vj (j = p3/2 or f5/2) configuration is tentatively assigned to it.     

TibetⅡ/HD阵列寻找来自蟹状星云的TeVγ射线

羊八井二期阵列(TibetⅡ)和加密阵列HD(HighDensity)分别从1995年和1996年成功地运行以来,已经积累了大量的数据.报道了利用TibetⅡ在1995年10月至1997年9月、HD阵列在1997年2月至8月收集的数据寻找来自蟹状星云(CrabNebula)方向的10TeV和3TeVγ射线稳定发射的初步结果.分析表明,来自CrabNebula的3TeVγ射线的累积信号事例数显示了稳定增长的趋势,显著性达到了3.2σ,但没有发现10TeV和30TeVγ射线稳定发射的迹象.     

Clifford分析中具有超正则核的T算子的性质

讨论了Clifford分析中具有超正则核的T(Ieodorescu)算子的基本性质.T算子是定义在区域上的奇异积分算子,它在广义解析函数理论和Vekua理论中起着重要的作用.在复分析中关于T算子的理论已经发展得很完善,但在Clifford分析中,具有超正则核的T算子的相关性质还没有得到研究.研究了Clifford分析中具有超正则核的T算子的基本性质,得到了这个算子在ΩR_+~(n+1)上的一致有界性,Hlder连续性以及这个算子的γ次可积性.     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.