检索结果-南通市图书馆

Thermal analysis of the baffle structure of the solar Space Telescope

Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1755-1764页

作者： LI Rong1,2.3 & WANG Sen1,3 1 national astronomical {2.,chinese academy of sciences,Beijing 100012,china 2.Graduate University of chinese academy of sciences,Beijing 100049,china {12.,national astronomical observatories of chinese academy of sciences,Beijing 100012,china 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Key Laboratory of Solar Activity National Astronomical Observatories of Chinese Academy of Sciences Beijing 100012 China

The SST(Space solar Telescope) is an astronomical telescope with a primary mirror of 1 m in *** observes the sun with a small view field to ensure that its high spatial resolution imaging has 0.1″-0.15″ and high SNR(signal to noise ratio).Surrounding the small view field is still the sun,which is an intense source of both heat and stray *** baffles(the main baffle,the aperture,and the outer baffle),which are used to eliminate the stray light,will change the thermal flux in the SST and will weaken the effect of the thermal control *** this study,the compatibility analysis of the thermal effect of baffle structures in SST is *** GCF(Geometry Composing Function) and BRDF(Bidirectional Reflectance Distribution Function),which are two inherent related parameters in the compatibility analysis,are *** objective and method of the compatibility analysis are *** the thermal analysis software,the temperature fields are calculated for different lengths of the main baffle,different radii of apertures,different lengths of the outer baffle with a 3' tilt angle and 16' tilt angle,and different tilt angles of the outer baffle with a 2.0 mm length.A series of configurations and sizes of the baffles are studied with the goals of both thermal control and elimination of stray *** design of the baffle structure of SST is achieved:the main baffle of length 4100 mm,the internal shield of radius 494 mm,the outer baffle of length 2.0 mm,and the outer baffle of tilt angle 3' are successfully *** paper presents the relationship between the thermal control design and stray light elimination plan in the *** aims of the optimal design of the baffle structure of SST are *** thoughts and methods of the optimal analysis are also useful for similar optical telescopes designed for solar observation.

关键词： baffle the main baffle the outer baffle GCF BRDF

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

What does the Sun tell and hint now?

引用

Research in Astronomy and Astrophysics 2009年第9期9卷 959-965页

作者： Ke-Jun Li1,2.1 national astronomical {2. /Yunnan Observatory,chinese academy of sciences,Kunming 650011,china 2.key laboratory of solar activity,national astronomical {2.,chinese academy of sciences,Beijing 100012,china national astronomical {2./Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China key laboratory of {2. activity National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

Some historical records, which have held since the beginning of modern solar activity cycles, are being broken by the present Sun： cycle 2. records the longest cycle length and fall time; latitudes of high-latitude sunspots belonging to a new cycle around the minimum time of the cycle are statistically the lowest at present, compared with those of other cycles; there are only one or no sunspots in a month appearing at high latitudes for 58 months, which is the first time that such a long duration has been observed. The solar dynamo is believed to be slowing down due to：（1） the minimum smoothed monthly mean sunspot number is the smallest since cycle 16 onwards, and even probably among all modern solar cycles; and （2. once the time interval between the first observations of two neighboring sunspot groups is larger than 14 d, it should be approximately regarded as an observation of no sunspots on the visible solar disk, called a spotless event. Spotless events occur with the highest frequency around the minimum time of cycle 2., and the longest spotless event also appears around the minimum time for observations of the Sun since cycle 16. Cycle 2. is expected to have the lowest level of sunspot activity from cycle 16 onwards and even probably for all of the modern solar cycles.

关键词： Sun: activity -- Sun: general -- sunspots

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

2.ASS photometry and age estimation of the globular clusters in the outer halo of M31

引用

Research in Astronomy and Astrophysics 2012年第2期12卷 115-126页

作者： Jun Ma 1,2. national astronomical {2.,chinese academy of sciences,Beijing 100012,china 2.key laboratory of Optical Astronomy,national astronomical {2.,chinese academy of sciences,Beijing 100012,china national astronomical {2. Chinese Academy of Sciences Beijing 100012 China key laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present the first photometric results in J, H and Ks from 2.ASS （Two Micron All Sky Survey） imaging of 10 classical globular clusters （GCs） in the far outer regions of M31. Combined with the V and I photometric data from previous literature, we constructed a color-color diagram between J - Ks and V - Ⅰ. By comparing the integrated photometric measurements with evolutionary models, we estimate the ages of these clusters. The results showed that all of these clusters are older than 3 × 109 yr, and among them four are older than 10 Gyr and the other six have intermediate ages between 3 - 8 Gyr. The masses for these outer-halo GCs are from 7.0 × 104 M to 1.02.× 10^6 M. We argued that GC2.and GC3, whose ages, metallicities and distance moduli are almost the same, were accreted from the same satellite galaxy, if they did not form in situ. The statistical results show that the ages and metallicities of these 10 M31 outer-halo GCs do not vary with projected radial position, and a relationship between age and metallicity does not exist.

关键词： galaxies: halos - galaxies: individual (M31) - star clusters: general

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A method to predict amplitude and date of maximum sunspot number

引用

chinese Science Bulletin 2000年第14期45卷 1287-1290页

作者： HAN YanbenBeijing astronomical Observatory, chinese {2. of sciences, national astronomical observatories, chinese {2. of sciences, Beijing 100012, china Beijing astronomical Observatory Chinese Academy of Sciences National Astronomical Observatories Chinese Academy of Sciences Beijing China

A method to predict the amplitude and date of the maximum sunspot number is introduced. The regression analysis of the relationship between the variation rate of monthly sunspot numbers in the initial stage of solar cycles and both of the maximum and the time-length of ascending period of the cycle showed that they are closely correlative. In general, the maximum will be larger and the ascending period will be shorter when the rate is larger. The rate of sunspot numbers in the initial 2.years of the 2.rd cycle is thus analyzed based on these grounds and the maximum of the cycle is predicted. For the smoothed monthly sunspot numbers, the maximum will be about 139.2.±18.8 and the time-length of ascending period will be about 3.31 ±0.42.years, that is to say, the maximum will appear around the spring of the year 2.00. For the mean monthly ones, the maximum will be near 170.1±2..9 and the time-length of ascending period will be about 3.42.±0.46 years, that is to say, the appearing date of the maximum

关键词： solar activity prediction sunspot number 2.rd solar cycle.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Spectroscopic study of globular clusters in the halo of M31 with the Xinglong 2.16 m telescope

引用

Research in Astronomy and Astrophysics 2011年第11期11卷 1298-1310页

作者： Zhou Fan1,2.Ya-Fang Huang1,2.Jin-Zeng Li1,2.Xu Zhou1,2.Jun Ma1,2.Hong Wu1,2.Tian-Meng Zhang1,2.and Yong-Heng Zhao1,2.1 national astronomical {2.,chinese academy of sciences,Beijing 100012,china 2.key laboratory of Optical Astronomy,national astronomical {2.,chinese academy of sciences,Beijing 100012,china national astronomical {2. Chinese Academy of Sciences Beijing 100012 China key laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present spectroscopic observations for 11 confirmed globular clusters(GCs) of M31 with the OMR spectrograph on the 2.16 m telescope at the Xinglong site of national astronomical {2.,chinese academy of *** of our sample clusters are located in the halo of M31 and the most remote one is out to a projected radius of 78.75 kpc from the galactic *** all our sample clusters,we measured the Lick absorption-line indices and radial *** is noted that most GCs in our sample are distinct from the HI rotation curve of galaxy M31,especially for B514,MCGC5,H12.and B517,suggesting that most of our sample clusters do not have a kinematic association with the star-forming young disk of the *** separately fitted the absorption line indices from the updated stellar population model of Thomas et *** two different tracks of Cassisi and Padova,by applying the χ2.minimization *** fitting results show that all our sample clusters are older than 10 Gyr,and metal-poor(2.38 ≤ [Fe/H] ≤ 0.91 dex).After merging the spectroscopic metallicity of our work with the previously published ones,we extended the cluster sample out to a projected radius of 117 kpc from the galaxy's *** found the metallicity gradient exists for all the confirmed clusters with a slope of 0.02. ± 0.001 dex kpc ***,the slope turns out to be 0.018 ± 0.001 dex kpc 1 for all the halo clusters,which is much *** we only consider the outer halo clusters with rp > 2. kpc,the slope becomes 0.010 ± 0.002.dex kpc 1 and if one cluster G001 is excluded from the outer halo sample,the slope is 0.004 ± 0.002.dex kpc ***,we conclude that the metallicity gradient for M31's outer halo clusters is not significant,which agrees well with previous findings.

关键词： galaxies individual(M31) — galaxies star clusters — globular clusters general — star clusters general

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Projection Effects on Physical Parameters Obtained from solar Vector Magnetograms

引用

chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 174-182页

作者： Hui Li Purple Mountain Observatory, chinese academy of {2., Nanjing 2.0008 national astronomical observatories, chinese academy of {2., Beijing 100012 Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 []National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

Projection effects in Huairou solar vector magnetograms are corrected by transferring or mapping the observed vector magnetogram in the image plane to the heliographic plane (planar correction) and to the heliospheric coordinate system (spherical correction). The magnetograms after the correction are considerably dif- ferent. The planar correction and the spherical correction lead to slightly different magnetic configurations, especially when the active region involved is far from the disk center. We also discuss the effects of the corrections on magnetic activity pa- rameters, such as magnetic shear, current helicity, etc. It is shown that the neutral line is obviously distorted after the mapping. The mapping generally decreases the average shear angle on the neutral line by several degrees when the active region is in the eastern hemisphere, and increases it when in the western hemisphere. In most of the cases studied, the correction reduces the current helicity imbalance, and sometimes even changes its sign. It is found that the current helicity imbalance may change its sign in its evolution when there are apparent fluxes emerging from the lower photosphere. The corrections increase the noise level of Bz greatly, and decrease the noise level of B~ slightly. The accuracy of the magnetic field measure- ment at Huairou is estimated to be better than 2. G and 150 G for the longitudinal and the transverse component, respectively.

关键词： Sun: magnetic fields ─Sun: activity ─Sun: photosphere

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Identification of ten new Galactic HII regions

引用

Science china(Physics,Mechanics & Astronomy) 2010年第6期53卷 1144-1152页

作者： RUAN GuiPing 1,2.& SHI WeiBin 1,2.1 Shandong Provincial key laboratory of Optical Astronomy and {2.-Terrestrial Environment,School of Space Science and Physics,Shandong University at Weihai,Weihai 2.42.9,china 2.key laboratory of Optical Astronomy,national astronomical observatories,chinese academy of sciences,Beijing {12.,china 1. Shandong Provincial key laboratory of Optical Astronomy and {2.-Terrestrial Environment School of Space Science and Physics Shandong University at Weihai Weihai 264209 China2. Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We discovered ten large HII regions in the Sino-German λ6 cm polarization survey of the Galactic plane. They have been identified according to their flat spectral indexes and the high ratio between the 60 μm infrared emission and the λ6 cm emission. The integrated flux densities as well as the sizes of these sources are given at 4800 MHz. Cross-identifications are made with other major radio catalogs.

关键词： radio continuum general-methods observational-HII regions

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A puzzle of the radio-quiet quasar PG 1407+2.5:Are optical and X-ray emissions produced from a relativistic jet?

引用

Science china(Physics,Mechanics & Astronomy) 2011年第1期54卷 183-186页

作者： CHEN Liang 1,2.3 & BAI JinMing 1,2.1 national astronomical {2./Yunnan Observatory,chinese academy of sciences,Kunming 650011,china 2.key laboratory for the Structure and Evolution of Celestial Objects,chinese academy of sciences,Kunming 650011,china 3 Graduate University of chinese academy of sciences,Beijing 100049,china 1. national astronomical {2./Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China2. Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China

PG 1407+2.5 is a radio quiet quasar that has a relativistic *** this report,we show some peculiar properties of its optical and X-ray emissions,which indicate possible non-thermal origins produced from the *** use a simple synchrotron + synchrotron self Compton (SSC) model to fit the emissions with different ratios of energy densities between the magnetic field and electrons (η≡U B/U e),which predicts a different γ-ray *** First LAT AGN Catalog (1LAC) did not include PG 1407+2.5,which indicates an upper limit of γ-ray *** upper limit constrains the ratio to be unreasonably large (η≥10 4-5).This inversely indicates that the optical and X-ray emissions may not be produced from the beaming *** discuss the physical implications of these results.

关键词： active galactic nuclei jet non-thermal emission PG 1407+2.5

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Pulsars in FIRST Observations

引用

chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 146-150页

作者： Xiang-Hua Li and Jin-Lin Han national astronomical {2., chinese academy of sciences, Beijing 100012 national astronomical {2. Chinese Academy of Sciences Beijing 100012

We identify 16 pulsars from the Survey of Faint Images of the Radio Sky at Twenty-cm (FIRST) at 1.4 GHz. Their positions and total flux densities are extracted from the FIRST catalog. By comparing the source positions with those in the PSR catalog, we obtain better determined positions of PSR J102.+1001, J1518+4904, J1652.2.51, and proper motion upper limits of PSR J0751+1807, J1012.5307, and J1640+2.2.. The proper motions of the other ten pulsars are consistent with the catalog values.

关键词： pulsar: general -stars: neutron

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Avoided crossings between non-radial modes in low mass RGB stars

引用

Research in Astronomy and Astrophysics 2012年第12期12卷 1655-1665页

作者： Jun-Jun Guo1,2.3,Yan Li1,2.and Xiang-Jun Lai1,2.1 national astronomical {2./Yunnan Observatory,chinese academy of sciences, Kunming 650011,china 2.key laboratory for the Structure and Evolution of Celestial Objects,chinese academy of sciences,Kunming 650011,china 3 Graduate University of chinese academy of sciences,Beijing 100049,china national astronomical {2./Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China key laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China Graduate University of chinese academy of {2. Beijing 100049 China

Non-radial p modes and g modes appear simultaneously in red giant stars. Their frequencies have different variation rates,causing their frequencies to become close during stellar evolution so that avoided crossings *** separation between regions where acoustic waves and gravity waves propagate for l=1,2.and 3 is different,which results in the coupling efficiency also being *** present the results of numerical computations of the models we *** find that the two kinds of modes for l=2.and 3 need to be closer in frequency in order for a complete exchange to occur,compared to the case for modes with l=*** scaled oscillation frequencies also present better regularity with evolution than modes with l=1. In order to study the effect of the avoided crossings in detail,we set the mode which has the smallest mode inertia to be the p *** plot the two kinds of modes for l =1,2.and 3 in frequency and periodéchelle diagrams and find modes of l=2.and 3 fit the two relations better;they are more equally spaced in frequency and period than modes with l=*** careful observation of the two kinds oféchelle diagrams for l=2.and 3,we still find that some p modes shift a little from being equally spaced in frequency and some g modes,which are close to those p modes in period,shift a little from being equally spaced in ***,we study the relation between the deviation from period being equally spaced and the mode inertia of g modes for different *** g modes of l=1 with a period closer to the p mode have less inertia and the deviation is bigger in the periodéchelle *** deviation is also obvious. However g modes of l=2.and 3 shift a little or have almost no deviation from being equally spaced in period,even though some of them may have strong coupling and close mode inertia like in the p ***,we suggest a possible method for measuring period spacing of g modes precisely using mixed g modes with l=2.and 3 that have fewer observed mixed g m

关键词： stars:oscillations-stars:red giants

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：