“不死鸟”终于返回地球 摆脱一个又一个危机的隼鸟号小行星探测器的航行轨迹

隼鸟号小行星探测器的任务是飞往名为“丝川”的小行星上,采集岩石样本,然后返回地球。它带着这种难度极高的使命,历时7年之久终于返回了地球。漫长的旅途之中,多次出现险情,每一次又奇迹般地化险为夷,完成了人类历史上首次地球与小行星之间的往返航程。我们就来追溯一下隼鸟号小行星探测器的艰难之旅吧!     

“隼鸟”采样的日日夜夜

2005年11月，探测器“隼鸟号”终于降落在距地球3亿千米的小行星“丝川”上，并完成了采样工作。这次计划的亮点是，“野心勃勃”的隼鸟号要把样品带回地球。第一次降落并不顺利，第二次虽然取得圆满成功，但是没高兴太久，人们就判断隼鸟号受到严重损坏，采样失败的可能性很大。隼鸟号虽然在世界上首次降落在月球以外的天体而且重新起飞意义重大，但是在其后几天发生的情况令人时而气馁，时而兴奋。本文将向读者详细介绍隼鸟号的奋斗历程。[编者按]     

太阳系的配角隐藏着太阳系历史秘密的卫星和小行星

我们居住的太阳系,不仅有太阳和行星,还有行星所携带的卫星,以及冥王星等矮行星、小行星和彗星等其他重要成员。日本的小行星探测器“隼鸟”号经过大约7年的太空之旅,采集到了小行星的物质样品并返回地球。这项探测任务的重要性在于,通过探测小行星有可能找到关于太阳系起源的线索。本文专门介绍通常被太阳和行星这样的主角掩盖了其重要性的、作为太阳系次要角色的卫星和小行星。     

2019年深空探测热点回眸

 深空探测是空间科学探索与发现的重要方式之一。2019年全球在轨工作的深空探测任务有29个，皆为非载人航天任务，主要开展了月球、火星和小行星等的探测、深空太阳观测及日-地L1点空间天气监测和L2点空间天文观测。在纪念人类登月50周年之际，美国加快推动重返月球的阿尔忒弥斯计划，中国嫦娥四号任务着陆器和玉兔二号月球车对月球背面的就位探测和巡视勘察陆续产出一批国际关注的科学成果。美国新视野号任务飞掠柯伊伯带小天体“2014 MU69”的首个科学成果揭示了该“接触双星系统”的发展、地质与构成。日本隼鸟二号任务完成对“龙宫”小行星的两次采样探测、启程返回地球。除了“史诗级”的太阳探测帕克号任务，被“遗忘”在L1点的多个超期服役的空间天气监测科学任务如SOHO、WIND等表现依然稳定和出色。2020年，人类将迎来探测火星的新发射窗口，中国、美国和欧洲等即将实施的多个火星任务引人注目。     

“不死鸟”历险记

<正>"隼鸟号"是世界上第一个成功带回小行星物质的探测器,在宇宙中历时7年,飞越了60亿千米的路程,经历种种艰辛完成各项任务。"隼鸟号"是一颗以小行星为目标的探测器。小行星就是指那些也绕着太阳转,但个头比行星小好多的天体,实际上它们比月球还要小很多。小行星上存在着许多矿物元素,这些元素可能是太阳系形成过程中残留下来的一些"印记",研究小"隼鸟号"的住务1验证离子发动机1000小时以上的工作能力。离子发动机是一种使用电力喷出阳离子流而产生推动力的发动机。2验证其"行星引力借力加速"能     

“隼鸟”亲吻“丝川”——在飞向小行星的路程上验证各项技术

2003年5月发射的工程实验探测器“隼乌”号从发射开始经过2年零6个月的航行，现正在进行几项“世界上首次”的技术验证，这些都是对今后探测行星极为重要的技术。本文将介绍“隼乌”号究竟是使用什么技术到达小行星的，以及预计今后还将完成哪些科学考察任务。[编者按]     

2018年深空探测热点回眸

 深空探测指人类航天器离开近地轨道、进入太阳系空间和宇宙空间，对地球以外天体（月球及以远天体）或空间环境开展的科学探测。2018年，国际深空探测叠彩纷呈：中国“嫦娥四号”成功实现国际首次月球背面软着陆并将开展巡视勘察；美国“洞察号”探测器登陆火星；向太阳系空间进发，朝向日心方向，欧洲空间局和日本合作研制的BeipiColombo探测器正飞向水星、美国“帕克号”探测器开启“史诗级”旅行去“触摸太阳”，远离日心方向，“新视野号”成功飞掠柯伊伯带的小行星“天涯海角”、“旅行者2号”突破日球层顶；美国“奥西里斯-REx”和日本“隼鸟2号”顺利抵达各自目标小行星执行采样任务。2018年，月球表面存在水冰、火星发现有机分子、太阳系边际再抵近等发现或突破对于探寻生命起源、太阳系起源和演化，拓展人类知识体系具有重要意义。     

2019年空间科学热点回眸

 回顾了2019年全球空间科学重要研究进展、美欧俄日等国家/地区最新重大发展战略以及新发射的空间科学重要任务平台，盘点了天基平台助力首次黑洞直接成像，宜居带系外行星的大气中存在水，“隼鸟2”号（Hayabusa 2）完成小行星采样，1年期双胞胎天地对比研究揭示人体空间适应性，美国明确在2024年前载人重返月球目标，俄罗斯计划分4个阶段开展月球综合探索与开发、至2040年全面建成月球基地，中国成功发射“太极一号”空间引力波探测技术实验卫星，美国成功发射“电离层探测器”（ICON）等重大成果和事件。     

小行星丝川的结构

<正>利用非常精确的地基观测设备,英国肯特大学的斯蒂芬·劳里(Stephen Lowry)和同事们研究了近地小行星"丝川"(第25143号小行星)的旋转速度,以及随时间的变化率。他们将精确的观测结果与小行星如何发热的最新理论结合起来。日本的"隼鸟号"探测器于2005年近距离拍到了这颗奇形怪状     

日本：“隼鸟”号探测器

日本宇宙航空研究开发机构近日宣布，“隼鸟”号小行星探测器，在距地球约2．9亿公里的小行星丝川成功着陆，并发射金属球采集了小行星岩石碎片。地面指挥人员已经确认，被金属球击碎弹起的岩石碎片已进入回收密封装置，密封装置的盖也已封闭，在小行星上采集岩石样本这在世界上是首次。小行星探测器绕太阳两周，运行20亿公里后在小行星着陆，第一次验证了日本行星探测技术，在日本宇宙开发史上也具有重要意义。     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-