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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 3.Key Laboratory of Solar Activity,national astronomical {2. 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

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A Date Recovery System launched for chronological studies in ancient china

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Science china(Physics,Mechanics & Astronomy) 2008年第1期51卷 105-110页

作者： LI Yong national astronomical {2.,Chinese {3. of sciences,Beijing 100012.china 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

Benefited from the performance of the Xia-Shang-Zhou Chronology Project(XSZP) in china and our new astronomical chronology method designed and processed for Chinese particular 60-day-cycle Ganzhi(the heavenly stems and earthly branches)date records,we launch a Date Recovery System(DRS)for ancient china. Of high analysis function,this software can recover and convert the complete or incomplete date information originally from Ganzhi style in the historical period of china to the Gregorian Calendar System,which may have wide applications in the area of literary history,archaeology and cultural relic,etc.,and solve the Goldbach Puzzles of Chinese *** an example,we give the detailed process for the sculptures on four bronze wares with the Ganzhi data and afterwards employ this software and provide their possible dates corresponding to Gregorian system.

关键词： chronology date ephemeris software

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Modeling earthquake indexes derived from the earthquake warning system upon the planet earth

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Science china(Physics,Mechanics & Astronomy) 2010年第12期53卷 2293-2299页

作者： LI Yong national astronomical {2., Chinese {3. of sciences, Beijing 100012, china 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

By studying the correlation between historical earthquake data and the distributional characteristics of parameters of solid earth tides in the earthquake epicenter, we are able to design a forecasting function of earthquake probability. We put forward a design method for the Earthquake Warning System. The model could theoretically simulate and be used to predict the probability of strong earthquakes that could occur anywhere at any time. In addition, the system could also conveniently obtain global or partial Modeling Earthquake Indexes to finally combine the precise pointing prediction and forecast of partial indexes. The literature quotes global data values, provided by NEIC, of 1544 M ≥ 6.5 earthquakes. It also gives examples of instantaneous earthquake indexes of the whole world and Taiwan Region on 1st January 2.10, UT=0:00 and the average earthquake index near the Taiwan Region. According to the 10-year pointing prediction of strong earthquakes in San Francisco, the literature provides the average earthquake index on 2.th June 2.15 (± 15 days), in its neighborhood.

关键词： earthquake earthquake warning system astrogeodynamics index

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2.ASS photometry and age estimation of the globular clusters in the outer halo of M3.

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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 M3.. 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 M3. 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 (M3.) - star clusters: general

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Simulations for terrestrial planets formation

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Science china(Physics,Mechanics & Astronomy) 2009年第5期52卷 794-803页

作者： ZHANG Niu 1,2.&JI JiangHui 2.3.1Graduate University of Chinese academy of {3.,Beijing 100049,{2. 2.urple Mountain Observatory,Chinese academy of {3.,Nanjing 2.0008,{2. 3.national astronomical observatories,Chinese academy of {3.,Beijing {13. Graduate University of Chinese academy of sciences Beijing 100049 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

In this paper,the formation of terrestrial planets in the late stage of planetary formation is investigated using the two-planet *** that time,the protostar formed for about 3.Ma and the gas disk *** the model,the perturbations from Jupiter and Saturn are *** of the mass of outer planet,and the initial eccentricities and inclinations of embryos and planetesimals are also *** results show that,terrestrial planets are formed in 50 Ma,and the accretion rate is about 60%-80%.In each simulation,3.4 terrestrial planets are formed inside"Jupiter"with masses of 0.15 -3.6M⊕.In the 0.5-4 AU,when the eccentricities of planetesimals are excited,planetesimals are able to accrete material from wide radial *** plenty of water material of the terrestrial planet in the Habitable Zone may be transferred from the farther places by this *** could also happen a few times between two major planets only if the outer planet has a moderate mass and the small terrestrial planet could survive at some resonances over time scale of 10 8 *** one of our simulations,commensurability of the orbital periods of planets is very ***,a librating-circulating 3.2.configuration of mean motion resonance is found.

关键词： astrophysics exoplanet planetary formation n-body simulation

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Expected Number Counts of Radio Galaxy Clusters

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Chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 106-111页

作者： Wei Zhou national astronomical {2., Chinese {3. of sciences, Beijing 100012 national astronomical {2. Chinese Academy of Sciences Beijing 100012

Clusters of galaxies may contain radio sources if they still experience successive mergers at present. This has been confirmed by radio observations that about 3.% of nearby clusters possess radio halos. We present a theoretical pre- diction of radio cluster counts using a semi-analytic approach which incorporates the empirical correlation between radio power and dynamical mass of clusters, and the cluster mass function described by the Press-Schechter formalism. The total population of radio clusters over the whole sky and their redshift distribution are given.

关键词： cosmology: theory-galaxies: cluster: general-radio sources:extended

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Simulation of interplanetary scintillation with SSSF and SSDF mode

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Science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 187-192页

作者： LIU LiJia & PENG Bo national astronomical {2., Chinese {3. of sciences, Beijing 100012, china 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

The sun has the biggest effect on the Earth in many ways. Observing the solar wind is an important method to study the solar-earth environment. Ground-based interplanetary scintillation observations are an effective method of monitoring solar wind speed, studying the random fluctuations of the interplanetary plasma and the structures of radio sources. Two modes of single-station observations, namely, single station-single frequency (SSSF) and single station dual-frequency (SSDF), are briefly introduced and numerically simulated in this paper. The SSSF mode are easier to carry out and has been widely used. Although the observing system and data processing system of the SSDF mode are more complicated, it can measure the solar wind speed more accurately. A new SSDF system is under construction in Miyun, NAOC (the national astronomical {2., Chinese {3. of sciences), with a 50 m telescope, which will serve the Meridian Project, and this paper is devoted to preparing for this new system.

关键词： interplanetary scintillation single station-single frequency single station dual-frequency simulation

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What does the Sun tell and hint now?

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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 {13. national astronomical {2./Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory of Solar 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

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A network flow algorithm to position tiles for LAMOST

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Research in Astronomy and Astrophysics 2009年第11期9卷 1277-1284页

作者： Guang-Wei Li and Gang Zhao national astronomical {2., Chinese {3. of sciences, Beijing 100012, china national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

We introduce the network flow algorithm used by the Sloan Digital Sky Survey （SDSS） into the sky survey of the Large sky Area Multi-Object fiber Spectroscopic Telescope （LAMOST） to position tiles. Because fibers in LAMOST＇s focal plane are distributed uniformly, we cannot use SDSS＇ method directly. To solve this problem, firstly we divide the sky into many small blocks, and we also assume that all the targets that are in the same block have the same position, which is the center of the block. Secondly, we give a value to limit the number of the targets that the LAMOST focal plane can collect in one square degree so that it cannot collect too many targets in one small block. Thirdly, because the network flow algorithm used in this paper is a bipartite network, we do not use the general solution algorithm that was used by SDSS. Instead, we give our new faster solution method for this special network. Compared with the Convergent Mean Shift Algorithm, the network flow algorithm can decrease observation times with improved mean imaging quality. This algorithm also has a very fast running speed. It can distribute millions of targets in a few minutes using a common personal computer.

关键词： methods data analysis -- methods statistical

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astronomical function and date of the Taosi observatory

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Science china(Physics,Mechanics & Astronomy) 2009年第1期52卷 151-158页

作者： WU JiaBi1, CHEN MeiDong2.& LIU CiYuan3.1 national astronomical {2., Chinese academy of sciences, Beijing 100012, china 2.Institute for the History of Natural Science, Chinese academy of sciences, Beijing 100010, china 3.national Time Service Center, Chinese academy of sciences, Xi’an 710600, china 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China 2. Institute for the History of Natural Science Chinese Academy of Sciences Beijing 100010 China 3. national Time Service Center Chinese Academy of Sciences Xi’an 710600 China

The Taosi site in Xiangfen County,Shanxi Province,may be the capital of the King Yao. Archeologists recently discovered a large semi-circular stamped-earth platform, II FJT1,which has a clear and definite pounded-earth central core together with a curved wall perforated by twelve gaps. The platform is said to be an ancient observatory used to determine the seasons by watching the sunrise. Each feature of II FJT1 was precisely measured and the data are reproduced in this paper. An astronomical analysis of slots E2.and E12.was carried out using the azimuths of the slots' centerlines and the vertical angle of the mountain ridge opposite, above which the sun rises. The results show that at present the sun is close to the two slots but does not exactly enter them at summer and winter solstice sunrise. Using 14C analysis archeologists dated the site to about 2.00 BC. Because of the secular change in the obliquity of the ecliptic,at that date on the summer solstice the half-risen sun would have appeared inside slot E12.just to the right of the centerline,and on the winter solstice the sun would have been exactly on the centerline of slot E2. This result provides compelling proof that II FJT1 is an ancient observatory.

关键词： astro-archeology astro-chronology Taosi culture ancient observatory time service

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