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Effects of various solar indices on accuracy of Earth’s thermospheric neutral density models

Science China(Physics,Mechanics & Astronomy) 2009年第7期52卷 1120-1128页

作者： wang hongbo1,2.& zhao changyin1 1 purple mountain observatory,{2., nanjing 2.0008, China 2.Graduate University of{2., Beijing 100049, China purple mountain {2. Chinese Academy of Sciences Nanjing 210008 China Graduate University of chinese academy of sciences Beijing 100049 China

Four kinds of solar indices F10.7, E10.7, S10, Mg10 and four thermospheric neutral density models, i.e., CIRA72. DTM94, NRLMSISE00 and JB2.06, are discussed. The CHAMP accelerometer data are used to calculate thermospheric total mass density. Based on the comparison of the model densities with CHAMP observations, the effects of various indices on the model accuracy are detected. It is found that under quiet and moderate solar conditions (F10.7160), all of the models’ errors are reduced about 15% by using E10.7 instead of F10.7, while under active solar conditions (F10.7>2.0) the error’s standard deviation using E10.7 increases quickly and causes the models’ accuracy to fall down. With regard to S10, Mg10, their effects under quiet solar conditions are inconspicuous. If under active solar conditions, they can reduce the model error’s standard deviation by 5%-10%, implying that S10, Mg10 make the model error more stable. The JB2.06 model, which was constructed by multi-solar-index (F10.7, S10, Mg10), is compared with DTM94 and NRLMSISE00 based on single-solar-index. It is found that JB2.06’s accuracy is better than DTM94’s, and is close to NRLMSISE00 under the quiet solar condition. During the solar burst occurring on October 2., 2.03, JB2.06 has been in best agreement with CHAMP observations. All in all, the new indices may improve thermospheric density models’ accuracy under some special conditions. Concretely, E10.7 may reduce the average error of models and S10, Mg10 may prevent the error’s divergence.

关键词： solar radiation index CHAMP accelerometer data neutrals density model

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Recent study of emission line star 3G71

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chinese Science Bulletin 1998年第6期43卷 470-473页

作者： HANG Hengrong 1,2.and XIA Jianping+1 1. purple mountain {2., chinese academy of sciences, nanjing 2.0008, China 2. Joint Laboratory for Optical Astronomy, chinese academy of sciences, nanjing 2.0008, China purple mountain {2. Chinese Academy of Sciences Nanjing China Joint Laboratory for Optical Astronomy Chinese Academy of Sciences Nanjing China

New spectral observations of 3G71 are presented. The main features of optical spectra which exhibit a lot of forbidden lines and unusual strong H-Balmer emission lines are discussed. Our data, together with its large IRAS infrared color excess and other characteristics, show evidence that the star may be a Herbig Ae/Be star rather than the optical counterpart of Be/X-ray source of 1H2.14+589.

关键词： Be/X-ray binary emission line IRAS identification Herbig Ae/Be star.

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An Alternative Explanation for a Screw-like Meteoric Train Photographed by Double-Station Observations

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chinese Journal of Astronomy and Astrophysics 2007年第6期7卷 814-822页

作者： Guang-Jie Wu1,2.1 National Astronomical Observatories/Yunnan observatory,chinese {2. of sciences,Kunming 650011 2.purple mountain observatory,chinese {2. of sciences,nanjing 2.0008 purple mountain {2. Chinese Academy of Sciences Nanjing 210008

Two-station observation of meteors, especially a meteor trains, provides an effective approach to the measurement of the physical parameters. We have collected four special groups of photographs of meteoric trains taken at two stations during Leonids 2.01. One representative group has been measured and analyzed in detail. An analysis has been reported in our first paper. In this paper, an alternative explanation for the screw-like meteoric train is suggested based on some physical calculations. The results reveal that this train has a screw-like structure and, apparently, spoke beams. The mother meteor of this train may be negatively charged and moves forward along a left-hand screw trajectory under the effect of the geomagnetic field. The spoke beams might be the visual effect of the long time exposure of many particles released from the disintegrated meteoroid.

关键词： meteors meteoroids -- magnetic fields

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A new class of symmetric periodic solutions of the spatial elliptic restricted three-body problem

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Science China(Physics,Mechanics & Astronomy) 2009年第9期52卷 1404-1413页

作者： XU XingBo1,2.& FU YanNing1 1 purple {2. {2., chinese academy of sciences, nanjing 2.0008, China 2.Graduate University of chinese academy of sciences, Beijing 100039, China 1. purple mountain {2. Chinese Academy of Sciences Nanjing 210008 China 2. Graduate University of chinese academy of sciences Beijing 100039 China

We show that there exists a new class of symmetric periodic solutions of the spatial elliptic restricted three-body problem. In such a solution, the infinitesimal body is confined to the vicinity of a primary and moves on a nearly circular orbit. This orbit is almost perpendicular to the orbital plane of the primaries, where the line of symmetry of the orbit lies. The existence is shown by applying a corollary of Arenstorf's fixed point theorem to a periodicity equation system of the problem. And this existence doesn't require any restriction on the mass ratio of the primaries, nor on the eccentricity of their relative elliptic orbit. Potential relevance of this new class of periodic solutions to real celestial body systems and the follow-up studies in this respect are also discussed.

关键词： periodic orbits spatial restricted three-body problem symmetric orbits averaging

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Suprathermal particle events observed by WIND spacecraft in interplanetary space during 1995―1999 and their classification

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Science China(Technological sciences) 2008年第9期51卷 1542-1553页

作者： SUN LingPeng1,2. WU DeJin1 & wang DeYu1 1 purple {2. observatory, chinese academy of sciences, nanjing 2.0008, China 2.Graduate School of chinese academy of sciences, Beijing 100049, China purple mountain {2. Chinese Academy of Sciences Nanjing 210008 China Graduate School of chinese academy of sciences Beijing 100049 China

Fifty-five suprathermal particle events were selected from WIND observations between 1995 and 1999. Based on systematic analysis on the observational characteristics of these events a two-parameter (the rising time and the flux ratio of electrons to protons in each event) classification method was proposed to classify these events. The three clas-sified classes are (1) impulsive electron events with the flux ratio of electrons to protons being bigger than 1 and rising time being shorter than 2.0 min, (2. impulsive proton events with the flux ratio being smaller than 1 and rising time being shorter than 2.0 min, and (3) gradual proton events with the flux ratio being smaller than 1 and the rising time being longer than 2.0 min. In the past, "impulsive solar electron events" were under in-tense research. However, because the selection standards of their velocity dispersions or pitch-angle distributions were inadequate, statistical surveys of selected events were dif-ferent from each other and even some conclusions were not consistent with the theory, for example, the relation of type-III solar radio bursts to the "impulsive solar electron events". The first class of impulsive electron events are associated with type-III radio bursts and with clear velocity dispersions; therefore they ought to originate from the Sun. The second class of the events, which have short continuance time and usually are not associated with type-III radio bursts and without velocity dispersion, are still far away from inter-planetary shocks and most of them do not one-to-one correspond to corrotating interact-ing regions (CIRs); such events are possible results of local interplanetary magnetic field reconnection or electromagnetic disturbances. Finally, about 2.3 gradual proton events of the third class occur with interplanetary shocks, the delay times of which are almost equal to the rising time. Some of these events can be understood as particle accelerations by shocks.

关键词： suprathermal particles solar wind plasma solar eruptive activity interplanetary active regions

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Molecular Gas and Dust in the Massive Star Forming Region S 2.3 IR

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chinese Journal of Astronomy and Astrophysics 2004年第5期4卷 440-454页

作者： Rui-Qing Mao and Qin Zeng1 purple mountain {2., chinese academy of sciences, nanjing 2.0008 2.National Astronomical Observatories, chinese academy of sciences, Beijing 100012 National Astronomical Observatories CAS NAOC Beijing 100012 China

The massive star forming region S 2.3 IR is observed in the molecular lines CO J = 2.1, 3–2. NH3 (1,1), (2.2. and the 870 um dust continuum. Four submillimeter continuum sources, labelled SMM 1–4, are revealed in the 870 um dust emission. The main core, SMM1, is found to be associated with a deeply embedded near infrared cluster in the northeast; while the weaker source SMM2.coincides with a more evolved cluster in the southwest. The best fit spectral energy distribution of SMM1 gives an emissivity of β = 1.6, and temperatures of 32.K and 92.K for the cold- and hot-dust components. An SMM1 core mass of 2.6 M☉, and a total mass of 445 M☉ are estimated from the 870 um dust continuum emission. SMM1 is found to have a temperature gradient decreasing from inside out, indicative of the presence of interior heating sources. The total outflow gas mass as traced by the CO J = 3–2.emission is estimated to be 35 M☉. Low velocity outflows are also found in the NH3 (1,1) emission. The non-thermal dominant NH3 line width as well as the substantial core mass suggest that the SMM1 core is a ``turbulent, massive dense core', in the process of forming a group or a cluster of stars. The much higher star formation efficiency found in the southwest cluster supports the suggestion that this cluster is more evolved than the northeast one. Large near infrared photometric variations found in the source PCS-IR93, a previously found highly polarized nebulosity, indicate an underlying star showing the FU Orionis type of behavior.

关键词： ISM: jets and outflows ISM: molecules ISM: dust, extinction stars:formation ISM: individual

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Autonomous satellite constellation orbit determination using the star sensor and inter-satellite links data

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Science China(Physics,Mechanics & Astronomy) 2010年第5期53卷 966-974页

作者： GAN QingBo1,2.MA JianBo1 & XU Jin1 1 purple mountain {2.,chinese academy of sciences,nanjing 2.0008,China 2.Graduate University of chinese academy of sciences,Beijing 100049,China 1. purple mountain {2. Chinese Academy of Sciences Nanjing 210008 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

A method of autonomous orbit determination for a satellite constellation using a star sensor combined with inter satellite links(ISLs) is *** types of simulated observation data,Three-Satellite Constellation ISLs and background stellar observations by a CCD star sensor,are first *** on these data,an observation equation is built for the constellation joint autonomous orbit determination,in which the simulations are *** accuracy of this method with different orbital determination models are analyzed and compared with regard to the effect of potential measurement *** results show that autonomous satellite constellation orbit determination using star sensor measurement and ISLs data is ***,this paper arrives at several conclusions which contribute to extending this method to a more general satellite constellation.

关键词： satellite constellation star sensor inter-satellite links autonomous orbit determination

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The red damping wing of Gunn-Peterson trough in the high redshift GRBs

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Science China(Physics,Mechanics & Astronomy) 2009年第9期52卷 1428-1433页

作者： XU Zhou1,2.& WEI DaMing1,3 1 purple {2. {2., chinese academy of sciences, nanjing 2.0008, China 2.Graduate University of chinese academy of sciences, Beijing 100012. China 3 Joint Center for Particle Nuclear Physics and Cosmology of purple {2. {2.-nanjing University, nanjing 2.0008, China purple mountain {2. Chinese Academy of Sciences Nanjing 210008 China Graduate University of chinese academy of sciences Beijing 100012 China Joint Center for Particle Nuclear Physics and Cosmology of purple mountain {2.-nanjing University Nanjing 210008 China

We calculate the red damping wing of Gunn-Peterson trough taking the evolution of the neutral fraction into consideration and take a clear look at the ionized region around the ionizing sources. We get the result that the damping wing flux feature is mainly determined by the neutral hydrogen outside the ionized bubble and the cut off in the damping wing would be useful to get the size of the ionized bubble. We also fit the red damping wing of the recently discovered high redshift GRB080913 and find that the ionized bubble is too small to create apparent cut off in the spectrum of this burst.

关键词： cosmology theory intergalactic medium gamma ray burst

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Development of superconducting mixers for THz astronomy

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Science China(Information sciences) 2012年第1期55卷 120-126页

作者： SHI ShengCai1,2.1purple mountain {2.,chinese academy of sciences,nanjing 2.0008,China 2.ey Laboratory of Radio Astronomy,chinese academy of sciences,nanjing 2.0008,China 1. purple mountain {2. Chinese Academy of Sciences Nanjing 210008 China2. Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing 210008 China

The terahertz(THz)regime,loosely defined as 0.1-10 THz,is the last frequency window to be fully explored in *** particular,it is a regime in which there are rich molecular rotation lines and atomic fine structure *** are very important tracers for studying the dynamics of astronomical objects such as stars and planetary *** those spectral lines usually makes use of coherent detectors(i.e.,heterodyne mixers).With sensitivity approaching the quantum limit,superconducting mixers have become the coherent detector of choice in THz *** this paper we mainly introduce the superconducting mixers developed at purple mountain {2. and those for international collaborative projects.

关键词： terahertz detection superconducting mixer quantum limit

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The simulation of GCRs at near earth interplanetary locations for radioprotection

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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1739-1745页

作者： BAO Gang purple mountain {2.,chinese academy of sciences,nanjing 2.0008,China 1. purple mountain {2. Chinese Academy of Sciences Nanjing 210008 China

The interplanetary radiation environment is detrimental to space missions,giving rise to cumulative damage to both astronauts and payloads and enhanced background levels in ***,there is a pressing need for a reliable simulation of these harmful effects for risk assessment and shielding optimization in manned space *** have modeled the interaction processes of the two most abundant galactic cosmic ray particle fluxes(protons and helium nuclei) using the Geant4 toolkit for a given space vehicle *** total energy deposited due to protons and helium nuclei is calculated in this work,and the energy deposited due to the secondary particles generated by this radiation is also estimated.

关键词： radioprotection simulation Geant4 cosmic rays

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