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There is a controversy in the area of nonextensive statistical mechanics regarding the form of the expectation value of a physical quantity. Two definitions have been discussed in the literature: one is the ordinary definition and the other is the normalized q-expectation value associated with the escort distribution. Here, it is proved that the normalized q-expectation value is the correct one to be employed. The Shore-Johnson theorem is used to show that the formalism with the normalized q-expectation value is theoretically consistent with minimum cross entropy principle, whereas the ordinary expectation value has to be excluded.  相似文献   

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恒星形成于分子云环境中。近30多年的观测研究使得天文学家对小质量恒星的形成有了相对明确的认识:小质量恒星通过坍缩、吸积和外向流的路标而形成。至于大质量恒星,其形成过程还存在着许多不确定因素,现有的观测证据表明:大质量恒星也可能通过坍缩、吸积和外向流的路标来形成,但也不排除在星团中通过中小质量恒星聚合而成的因素。大质量恒星形成与致密电离氢区(UCHII)成协较好,而与大质量恒星形成区成协的分子云环境中,既有大质量恒星也有小质量恒星形成。综述了恒星形成各个阶段的观测结果和研究现状以及成协的天体物理环境情况。未来的观测和研究重点在于,大质量恒星形成以及星团环境中的恒星形成。  相似文献   

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Solar eruptions are the most spectacular events in our solar system and are associated with many different signatures of energy release including solar flares, coronal mass ejections, global waves, radio emission and accelerated particles. Here, we apply the Coronal Pulse Identification and Tracking Algorithm (CorPITA) to the high-cadence synoptic data provided by the Solar Dynamics Observatory (SDO) to identify and track global waves observed by SDO. 164 of the 362 solar flare events studied (45%) were found to have associated global waves with no waves found for the remaining 198 (55%). A clear linear relationship was found between the median initial velocity and the acceleration of the waves, with faster waves exhibiting a stronger deceleration (consistent with previous results). No clear relationship was found between global waves and type II radio bursts, electrons or protons detected in situ near Earth. While no relationship was found between the wave properties and the associated flare size (with waves produced by flares from B to X-class), more than a quarter of the active regions studied were found to produce more than one wave event. These results suggest that the presence of a global wave in a solar eruption is most likely determined by the structure and connectivity of the erupting active region and the surrounding quiet solar corona rather than by the amount of free energy available within the active region.  相似文献   

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阐述当今天体力学前沿课题中的几个热点问题,近地小行星与地球的交会及其动力演化,航天器定轨新手段中的得一星跟踪自主定轨方法以及星际探测中的轨道力学问题。  相似文献   

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This article provides some astronomical background for a systematic study of the lunar regolith. The Moon, like other atmosphere-less bodies, is the subject to all kinds of cosmic radiation, which are imprinted in the lunar surface. Therefore, the study of the lunar regolith for signs of cosmic radiation can assist to trace the history of changes in these emissions over time. Mostly changes in the solar wind and galactic cosmic rays are very interesting at time intervals from a few tens of millions of years to several billion years. The paper develops the idea of paleoregolith, the possible location of which can be seen on the slopes of some craters (Euler, Bessel) in images obtained by camera of LRO spacecraft (LROC). Because of the complexities of placing a spacecraft on the slopes of craters, some other possible locations of paleoregolith are offered to consideration. To study the recent history of the evolution of the Moon and the inner planets (up to 200 million years) the stored information in impact and volcanic melts, which are widely represented in the LROC images, should be considered.  相似文献   

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叙述了我国天文科技期刊论文中计量单位存在的问题 ,提出了正确使用计量单位的看法  相似文献   

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本文讨论了摄谱仪中若干畸象系统,它们的作用是缩放入射狭缝的象单在高或宽的方向的尺寸,这等效于在狭缝前、后单在子午面内或弧矢面(色散方向面)内改变光束的孔径角,也等效于准直光束单在子午面或弧矢面内缩放光束宽度,在讨论中指出了准直畸象系统优于非准直畸象系统。 在着重讨论和分析准直畸象系统的不同形式时,我们提出了棱镜系统,它具有许多优点,是最为可行的方案。  相似文献   

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Ten years ago, Forrest presented the first astronomical images with an SBRC 32×32 InSb array camera at the first NASA-Ames Infrared Detector Technology Workshop. Soon after, SBRC began development of 58×62 InSb arrays, both for ground-based astronomy and for SIRTF. By the time of the 1987 Hilo workshop Ground-based Astronomical Observations with Infrared Array Detectors astronomical results from cameras based on SBRC 32×32 and 58×62 InSb arrays, a CE linear InSb array, and a French 32×32 InSb CID array were presented. And at the Tucson 1990 meeting Astrophysics with Infrared Arrays, it was clear that this new technology was no longer the province of IR pundits, but provided a tool for all astronomers. At this meeting, the first astronomical observations with SBRC's new, gateless passivation 256×256 InSb arrays will be presented: they perform spectacularly!In this review, I can only broadly brush on the interesting science completed with InSb array cameras. Because of the broad wavelength coverage (1–5.5 m) of InSb, and the extremely high performance levels throughout the band, InSb cameras are used not only in the near IR, but also from 3–5.5 m, where unique science is achieved. For example, the point-like central engines of AGNs are delineated at L and M, and Br and 3.29 m dust emission images of galactic and extragalactic objects yield excitation conditions. Examples of imaging spectroscopy, high spatial resolution imaging, as well as deep, broad-band imaging with InSb cameras at this meeting illustrate the power of InSb array cameras.  相似文献   

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中国天文学名词审定委员会在《天文学进展》第3卷第4期(1985)、第7卷第2期(1989)、第9卷第2期(1991)、第12卷第2期(1994)、第15卷第1期(1997)、第16卷第2期(1998)、第17卷第4期(1999)、第19卷第3期(2001)和第21卷第1期(2003)上刊登了本委员会提供的10批共1581个天文学名词的推荐译名。现再推荐第11批93个,其中大多数是近年出现的天文学新词。希望读者在使用过程中对译名提出改进意见。  相似文献   

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中国天文学会名词审定委员会从1985年起开始在<天文学进展>发表天文学名词的推荐译名,到2009年已公布16批共2536个名词.现再推荐第17批114个名词,其中大多数是近年出现的天文学新词.希望读者在使用过程中对译名提出改进意见.  相似文献   

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中国天文学会名词审定委员会从1985年起开始在《天文学进展》发表天文学名词的推荐译名,到2004 年已公布了12批共2025个名词。现再推荐第13批126个名词,其中大多数是近年出现的天文学新词。希望读者在使用过程中对译名提出改进意见。  相似文献   

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中国天文学名词审定委员会在《天文学进展》第3卷第4期(1985)、第7卷第2期(1989)、第9卷第2期(1991)、第12卷第2期(1994)、第15卷第1期(1997)、第16卷第2期(1998)、第17卷第4期(1999)、第19卷第3期(2001)、第21卷第1期(2003)和第22卷第1期(2004)上刊登了本委员会提供的11批共1674个天文学名词的推荐译名.现再推荐第12批351个,其中大多数是近年出现的天文学新词。希望读者在使用过程中对译名提出改进意见。  相似文献   

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中国天文学会名词审定委员会从1985年起开始在<天文学进展>发表天文学名词的推荐译名,到2008年已公布15批共2431个名词.现再推荐第16批105个名词,其中大多数是近年出现的天文学新词.希望读者在使用过程中对译名提出改进意见.  相似文献   

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中国天文学名词审定委员会在《天文学进展》第3卷第4期(1985)、第7卷第2期(1989)、第9卷第2期(1991)、第12卷第2期(1994)、第15卷第1期(1997)、第16卷第2期(1998)、第17卷第4期(1999)和第19卷第3期(2001)上刊登了本委员会提供的1431个天文学名词的推荐译名。现再推荐第10批130个,其中大多数是近年出现的天文学新词。希望读者在使用过程中对译名提出改进意见。  相似文献   

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中国天文学会名词审定委员会从1985年起开始在《天文学进展》发表天文学名词的推荐译名,到2006年已公布了13批共2151个名词。现再推荐第14批129个名词,其中大多数是近年出现的天文学新词,希望读者在使用过程中对译名提出改进意见.  相似文献   

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我国天文视宁度Fried参数r0的计算与统计分析   总被引:2,自引:0,他引:2  
在塔塔尔斯基理论模式下,使用全国81个探空气象站1986—1995年10年探空资料计算了各测站不同高度上的Pried参数r0,统计结果表明,r0年平均值存在明显的地理分布,高值中心在3000m高度上是夏河合作、丽江和上海;在1500m高度上为民勤和贵阳,在900m高度上为汉中;在测站海拔高度上为定日,r0的月平均值的地理分布存在显著的季节变化,这种变化与东亚副热带急流季节性变化相吻合.  相似文献   

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The latest version of the planetary part of the numerical ephemerides EPM (Ephemerides of Planets and the Moon) developed at the Institute of Applied Astronomy of the Russian Academy of Sciences is presented. The ephemerides of planets and the Moon were constructed by numerical integration in the post-Newtonian metric over a 140-year interval (from 1880 to 2020). The dynamical model of EPM2004 ephemerides includes the mutual perturbations from major planets and the Moon computed in terms of General Relativity with allowance for effects due to lunar physical libration, perturbations from 301 big asteroids, and dynamic perturbations due to the solar oblateness and the massive asteroid ring with uniform mass distribution in the plane of the ecliptic. The EPM2004 ephemerides resulted from a least-squares adjustment to more than 317000 position observations (1913–2003) of various types, including radiometric measurements of planets and spacecraft, CCD astrometric observations of the outer planets and their satellites, and meridian and photographic observations. The high-precision ephemerides constructed made it possible to determine, from modern radiometric measurements, a wide range of astrometric constants, including the astronomical unit AU = (149597870.6960 ± 0.0001) km, parameters of the rotation of Mars, the masses of the biggest asteroids, the solar quadrupole moment J 2 = (1.9 ± 0.3) × 10−7, and the parameters of the PPN formalism β and γ. Also given is a brief summary of the available state-of-the-art ephemerides with the same precision: various versions of EPM and DE ephemerides from the Jet Propulsion Laboratory (JPL) (USA) and the recent versions of these ephemerides—EPM2004 and DE410—are compared. EPM2004 ephemerides are available via FTP at ftp://qua-sar.ipa.nw.ru/incoming/EPM2004.__________Translated from Astronomicheskii Vestnik, Vol. 39, No. 3, 2005, pp. 202–213.Original Russian Text Copyright © 2005 by Pitjeva.  相似文献   

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