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A puzzle of the radio-quiet quasar PG 1407+265:Are optical and X-ray emissions produced from a relativistic jet?

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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 observatories/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 chinese academy of sciences National Astronomical Observatories/Yunnan Observatory Kunming China (GRID:grid.9227.e) (ISNI:***) chinese academy of sciences Key Laboratory for the Structure and Evolution of Celestial Objects Kunming China (GRID:grid.9227.e) (ISNI:***) Graduate University of chinese academy of sciences Beijing China (GRID:grid.458514.9) chinese academy of sciences National Astronomical Observatories/Yunnan Observatory Kunming China (GRID:grid.9227.e) (ISNI:***) chinese academy of sciences Key Laboratory for the Structure and Evolution of Celestial Objects Kunming China (GRID:grid.9227.e) (ISNI:***)

PG 1407+265 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+265,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+265

Study of the primordial lithium abundance

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Science china(Physics,Mechanics & Astronomy) 2011年第S1期54卷 67-72页

作者： LI ZhiHong1, LI ErTao1, SU Jun1, LI YunJu1, BAI XiXiang1, GUO Bing1, WANG YouBao1, CHEN YongShou1, HOU SuQing1, ZENG Sheng1, LIAN Gang1, SHI JianRong2 & LIU WeiPing1 1 china Institute of Atomic Energy, beijing 102413, china 2national astronomical observatories, chinese academy of sciences, beijing 100012, china china Institute of Atomic Energy Beijing China (GRID:grid.410655.3) (ISNI:***) chinese academy of sciences National Astronomical Observatories Beijing China (GRID:grid.9227.e) (ISNI:***)

Lithium isotopes have attracted an intense interest because the abundance of both 6Li and 6Li from big bang nucleosynthesis (BBN) is one of the puzzles in nuclear astrophysics. Many investigations of both astrophysical observation and nucleosynthesis calculation have been carried out to solve the puzzle, but it is not solved yet. Several nuclear reactions involving lithium have been indirectly measured at china Institute of Atomic Energy, beijing. The Standard BBN (SBBN) network calculations are then performed to investigate the primordial Lithium abundance. The result shows that these nuclear reactions have minimal effect on the SBBN abundances of 6Li and 7Li.

关键词： big bang nucleosynthesis element abundance nuclear reaction network

Time-variation of the near 5-month period of sunspot numbers

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chinese Science Bulletin 2002年第23期47卷 1969-1973页

作者： HAN Yanben1 & HAN Yonggang1,21. national astronomical observatories, chinese academy of sciences, beijing 100012, china 2. Department of Applied Mathematics, beijing Polytechnic University, beijing 100022, china national astronomical observatories Chinese Academy of Sciences Beijing China Department of Applied Mathematics Beijing Polytechnic University Beijing China

The variation of the near 5-month period of sunspot numbers is discussed on the basis of the wavelet transform of the daily sunspot number series in the 14th-22nd solar cycles. The result shows that the period exists in every cycle and its energy density (amplitude) is comparatively large in the peak section of the cycle. In the distinct cycle, the length and intensity of the period is different, which means that the period varies with time. The near 25-day period is also analyzed and it is found to be time-variable and even not very stable in the peak section of the cycle. The variations of the two periods show that the near 5-month period should not be simply regarded as the multiples of the near 25-day period.

关键词： solar activity sunspot time-variation wavelet.

Polynomial regression calculation of the Earth's position based on millisecond pulsar timing

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Research in Astronomy and Astrophysics 2012年第2期12卷 219-234页

作者： Feng Tian 1,2,zheng-Hong Tang 1,Qing-Zeng Yan 1,2 and Yong Yu 11 Shanghai astronomical Observatory,chinese academy of sciences,Shanghai 200030,china 2 Graduate University of chinese academy of sciences,beijing 100049,china Shanghai astronomical Observatory Chinese Academy of Sciences Graduate University of chinese academy of sciences

Prior to achieving high precision navigation of a spacecraft using X-ray observations, a pulsar rotation model must be built and analysis of the precise posi- tion of the Earth should be performed using ground pulsar timing observations. We can simulate time-of-arrival ground observation data close to actual observed values before using pulsar timing observation data. Considering the correlation between the Earth＇s position and its short arc section of an orbit, we use polynomial regression to build the correlation. Regression coefficients can be calculated using the least square method, and a coordinate component series can also be obtained; that is, we can calcu- late Earth＇s position in the Barycentric Celestial Reference System according to pulse arrival time data and a precise pulsar rotation model. In order to set appropriate param- eters before the actual timing observations for Earth positioning, we can calculate the influence of the spatial distribution of pulsars on errors in the positioning result and the influence of error source variation on positioning by simulation. It is significant that the threshold values of the observation and systematic errors can be established before an actual observation occurs; namely, we can determine the observation mode with small errors and reject the observed data with big errors, thus improving the positioning result.

关键词： autonomous positioning - millisecond pulsar - pulsar timing - re-gression analysis

A Check on the Cardassian Expansion Model with Type-la Supernovae Data

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chinese Journal of Astronomy and Astrophysics 2003年第4期3卷 341-346页

作者： Li Caonational astronomical observatories, chinese academy of sciences, beijing 100012

We use the magnitude-redshift relation for the type Ia supernova datacompiled by Riess et al. to analyze the Cardassian expansion scenario. This scenario assumes theuniverse to be flat, matter dominated, and accelerating, but contains no vacuum contribution. Thebest fitting model parameters are H_0 = 65.3 km s^(-1) Mpc^(-1), n = 0.35 and Ω_m = 0.05. When thehighest redshift supernova, SN 1997ck, is excluded, H_0 remains the same, but n becomes 0.20 andΩ_m, 0.15, and the matter density remains unreasonably low. Our result shows that this particularscenario is strongly disfavoured by the SNeIa data.

关键词： supernovae: general cosmology: theory distances and redshifts

Regulation mechanism of EM parameters in natural ferrite and its application in microwave absorbing materials

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Science china(Technological sciences) 2006年第1期49卷 38-49页

作者： zheng Yongchun1,2, WANG Shijie2, FENG Junming2, LI Chunlai1, OUYANG Ziyuan1,2, LIU Jianzhong1 & LI Xiaobiao2 1. national astronomical observatories, chinese academy of sciences, beijing 100012, china 2. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, chinese academy of sciences, Guiyang 550002, china national astronomical observatories Chinese Academy of Sciences Beijing 100012 China

Electromagnetic (EM) parameters (ε ′, ε ″, μ ′, μ″ ) of several M2+Fe2O4 and Fe2O3 type natural ferrites with different geological occurrences are measured in this pa-per. The measurement results show that EM parameters of a magmatic-occurring natural ferrite is very different from other types occurring from sedimentary-metamorphic iron deposit, hydrothermal vein iron deposit, outer contact of magmatic iron deposit. It has potential to be used as magnetic absorbent in microwave absorbing materials. After min-eral separation and concentration, this magmatic-occurring natural ferrite was processed into type A ferrite absorbent. Type A natural ferrite absorbent is a kind of magnetic material with low dielectric constants, high magnetic conductivity and high EM loss. Its EM pa-rameters are ε ′ = 58.60, ε ″ = 10.0, μ ′ = 1.2-1.5, μ ″ = 1.0-1.2, respectively. In order to illuminate the regulation mechanism of EM parameters, we studied the chemical and mineral composition of type A ferrite absorbent. There is high concentration of natural impurities, which regulate the EM parameters of type A ferrite greatly. For comparison, the other types of natural ferrite, single-phase magnetite and two-phase iron minerals (ilmen-ite and magnetite), have few impurity. Thus regulation mechanism of EM parameters was absent in these ferrites. As a result, the regulation of EM parameters is advantageous to develop type A natural ferrite as excellent absorbent, lowers the reflectivity coefficients and enhances the absorbing efficiency of MAM made from it. Furthermore, the impurities in type A natural ferrite and its effects on EM parameters are very difficult to simulate in the synthesize ferrite. The carbonyl-iron powder is another kind of absorbent that is used ex-tensively in MAM. To compare the absorbing properties of these two absorbent, type A natural ferrite and carbonyl-iron powder were mixed with rubber and processed into mi-crowave absorbing sheets with the same procedures and tec

关键词： natural impure ferrite, complex permittivity, complex permeability, microwave absorbing materials.

High Throughput SNP Genotyping with Two Mini-sequencing Assays

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Acta Biochimica et Biophysica Sinica 2004年第6期36卷 379-384页

作者： Chunqing LUO1,2#, Libin deng1#, and Changqing ZENG1,2* The Institute of Genetic and Developmental Biology, the chinese academy of sciences, beijing 100101, china 2beijing Genomics Institute, the chinese academy of sciences, beijing 101300, china The Institute of Genetic and Developmental Biology the Chinese Academy of SciencesBeijing 100101 China beijing Genomics Institute the Chinese Academy of SciencesBeijing 101300 China

Two mini-sequencing methods, FP-TDI (template-directed dye-terminator incorporation with fluorescence-polarization) and MassArray (matrix assisted laser desorption ionization time of flight detection mass spectrometry), were optimized. A numeric standard was introduced to evaluate the SNP scoring quality of FP-TDI assay, thus made the optimization work easier. At the same time, using multi-PCR technology, 8-plex genotyping of MassArray assay was successfully carried out, some softwares were developed and the data process of MassArray was highly automated. Then these two methods were applied to high throughput SNP genotyping, the accuracy, efficiency and robustness were compared. The result shows FP-TDI is more sensitive to the concentration of SNPprimer and PCR product, as well as extension cycles, the SNPprimer length of FP-TDI should be 24–30 bp long, whereas MassArray assay prefers to be as short as only 16 *** 6440 SNP sites of human chromosome 3 were genotyped in a sample of 90 individuals, 4792 sites by FP-TDI assay and 1648 sites by MassArray assay, the success rates of FP-TDI and MassArray were 67.7% and 93.6% respectively. The throughput of MassArray was higher than FP-TDI, and the cost of MassArray was lower, MassArray was more suitable for high throughput SNP genotyping.

关键词： SNP genotyping FP-TDI MassArray high throughput

Formation of Solar Delta Active Regions:Twist and Writhe of Magnetic Ropes

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chinese Journal of Astronomy and Astrophysics 2004年第6期4卷 563-577页

作者： Hong-QiZhang nationalastronomicalobservatories ChineseAcademyofSciencesBeijing100012

We analyze the process of formation of delta configuration in some well-known super active regions based on photospheric vector magnetogram observations. It is found that the magnetic field in the initial developing stage of some delta active regions shows a potential-like configuration in the solar atmosphere, the magnetic shear develops mainly near the magnetic neutral line with magnetic islands of opposite polarities, and the large-scale photospheric twisted field forming gradually later. Some results are obtained: (1) The analysis of magnetic writhe of whole active regions cannot be limited in the strong field of sunspots, because the contribution of the fraction of decayed magnetic field is non-negligible. (2) The magnetic model of kink magnetic ropes, supposed to be generated in the subatmosphere, is not consistent with the evolution of large-scale twisted photospheric transverse magnetic field and not entirely consistent with the relationship with magnetic shear in some delta active regions. (3) The proposition is that the large-scale delta active regions are formed from contribution by small-scale non-potential magnetic flux bundles generated in the subatmosphere.

关键词： sun activity sun flares sun magnetic fields

The Influence of Panel Gaps on the System NoiseTemperature of the FAST

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chinese Journal of Astronomy and Astrophysics 2001年第2期1卷 190-194页

作者： Yan Su and Guo-Ding Li (1 beijing astronomical Observatory, national astronomical observatories, chinese academy of sciences, beijing 100012 2 The Laboratory of Microwave and Digital Communication Technology, Tsinghua University, beijing 100084) beijing astronomical Observatory National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 The Laboratory of Microwave and Digital Communication Technology Tsinghua University Beijing 100084

A Five-hundred-meter Aperture Spherical Telescope (FAST), the largest single dish in the world, is proposed to be built in one of the karst depressions in Guizhou province. The main spherical reflector is to consist of about two thousand small panels, which can be adjusted to fit a paraboloid in real time. There are many slit-like gaps across the aperture due to manufacturing errors thermal effects and deviations between a sphere and a paraboloid. The influence of the energy leakage of the narrow gaps on the system noise temperature of the FAST reflector is discussed in this paper.

关键词： telescopes - methods: analytical - energy leakage