哈雷彗星正向地球飞来

据观测,哈雷彗星正以每秒10公里的速度向地球方向移动。天文学家根据它几次回归时的观测结果,考虑了行星对它的摄动以及彗星本身损失质量而引起的效应,计算出哈雷彗星的轨道要素并编算出详尽的星历表。1986年2月9日哈雷彗星经过轨道近日点,近日距为8781万公里。1985年11月27     

彗星轨道运动中的非引力效应

运用非引力模型II对Hale-Bopp彗星的非引力效应作一初步的探讨。     

变质量少体问题及其应用

该文以变质量质点动力学方程（密歇尔斯基方程）为基础,建立了变质量少体问题的运动方程,并利用小参数方法得到了变质量少体问题的分析解。文中还将研究结果应用到彗星运动上,讨论彗星轨道中非引力效应。指出非引力效应会导致某些彗星轨道半长径和偏心率等产生长期和周期变化,这些变化将明显地影响彗星运动的周期以及过近日点的时间和地点。因此在这些彗星精密定轨和探讨其轨道动力演化时应当考虑这种非引力效应。文末还具体计算了恩克彗星轨道中非引力效应。     

用小型望远镜拍摄哈雷彗星的彗尾

1985—1986年度哈雷彗星的回归是举世瞩目的天象。“国际哈雷彗星联测机构”(IHW)组织全世界的天文工作者进行统一的观测。通过对哈雷彗星的观测和研究,对了解太阳系起源等重大问题将有着积极的意义。彗星的大尺度观测主要是研究彗尾等离子体与太阳风之间的关系及彗尾随时间的变化,     

哈雷彗星及中国天文学家在新西兰的观测

历史上的哈雷彗星哈雷彗里是所有彗星中最著名的一颗。值得注意的是,这一彗星并非象常规那样以发现者的名字命名的,而是以预言它能周期性回归的英国天文学家哈雷的名字命名的,借助于牛顿的两体问题轨道理论,在比较了出现于1531、1607和1682年的三颗彗星的轨道特征后,哈雷认定这三颗彗星实系同一彗星,每隔76年左右回归一次。他预言在1758～1759年间哈雷彗星将再次回归。果然在1758年圣诞节,哈雷彗星如期出现。那时,哈雷本人已经谢世,但是正如他生前所说,“世界将会知道,这事是一个英国人预告过的”。     

令人眩目的海尔—波普彗星

“世纪彗星”何处寻所谓世纪彗星,是指本世纪出现的最明亮的彗星。那么,在本世纪见到的众多彗星中,谁能获此殊荣呢? 谁是“世纪彗星”“当然是哈雷彗星。”许多人会这样回答,其实不然。哈雷彗星名声虽大,但却不是本世纪最明亮的彗星。哈雷彗星的运动周期是是76年,并在本世纪回归过两次,即1910年和1986年,最亮时星等分别只有1等和3等,并不很亮。     

哈雷彗星回归周期特征的研究

哈雷彗星是太阳系成员之一,研究哈雷彗星及其回归周期的特征对解决太阳系及彗星的许多正在探索的问题,将会有极大的启示与进展。现值空间时代,哈雷彗星1986年回归,当然引起全世界各国的极大关注。由此,世界各主要大国都积极制定了探测计划。日本的“行星——A”计划,将于1985年2月或8月发射一个航天器与哈雷彗星相会。欧洲空间局也将于1985年7月发射一颗乔托卫星,予计经8个月后与哈彗星相遇。国际天文学会组成“IHW”机构,成立了天体测量、红外光谱和射电观测、大尺度现象观测、近核研究、光度学和编振测量、射电研究、光谱学和分光光度学等学科组,组织了1984年的观测试验。与此同时,各国科学工作者对哈雷     

哈雷彗星的照相观测及其定位

<正> 引言举世瞩目的哈雷彗星已经回归,全球性的观测研究早已展开,这对研究太阳系的起源和演化、生命的起源和演化等课题具有十分重要的意义。我们已于11月8日利用国产120折反式望远镜首次观测到哈雷彗星,并进行了近日来的连续跟踪观测,拍摄到了哈雷彗星的照片。本文综合了我们所获资料的其中一部分,并进行了初步归算,试图为小型望远镜的观测研究提供参考。     

哈雷彗星观测

彗星的观测研究,对研究太阳系的起源和演化、太阳风速度场的分布、太阳系空间磁场的结构以及彗星本身的结构及其物理化学特性等都有重大的意义.哈雷慧星是一颗非常典型的周期彗星,有着众所周知的七十六年回归周期,1985—1986年,它将再次回归太阳附近,这是国际天文界的一件大事,国际天文协会第十五委员会——“国际哈雷彗星监测”(Inter-national Halley Wetch,简称IHW.)将动员、组织和指导全世界的地面观测和宇宙飞船的空间近距离探测。     

低能光子的量子引力“遗迹”效应

量子引力理论是人类在探索自然界四种基本相互作用统一的道路上的终极目标.其中不少候选理论预言了在低能区的可观测效应,称为量子引力“遗迹”效应.本文讨论了量子引力理论对于低能区的光子色散关系的修正,和由此带来的可观测后果,以及现今实验观测上的检验与约束.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has