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| 1 | A Positioning System based on Communication Satellites and the Chinese Area Positioning System(CAPS)显示文摘The Chinese Area Positioning System(CAPS) is a positioning system based on satellite communication that is fundamentally different from the 3'G'(GPS,GLONASS and GALILEO) systems.The latter use special-purpose navigation satellites to broadcast navi-gation information generated on-board to users,while the CAPS transfers ground-generated navigation information to users via the communication satellite.In order to achieve accurate Positioning,Velocity and Time(PVT),the CAPS employs the following strategies to over-come the three main obstacles caused by using the communication satellite:(a) by real-time following-up frequency stabilization to achieve stable frequency;(b) by using a single carrier in the transponder with 36 MHz band-width to gain sufficient power;(c) by incorporating Decommissioned Geostationary Orbit communication satellite(DGEO),barometric pressure and Inclined Geostationary Orbit communication satellite(IGSO) to achieve the 3-D posi-tioning.Furthermore,the abundant transponders available on DGEO can be used to realize the large capacity of communication as well as the integrated navigation and communication.With the communication functions incorporated,five new functions appear in the CAPS:(1) combination of navigation and communication;(2) combination of navigation and high accu-racy orbit measurement;(3) combination of navigation message and wide/local area differen-tial processing;(4) combination of the switching of satellites,frequencies and codes;and(5) combination of the navigation message and the barometric altimetry.The CAPS is thereby labelled a PVT5C system of high accuracy.In order to validate the working principle and the performance of the CAPS,a trial system was established in the course of two years at a cost of about 20 million dollars.The trial constellation consists of two GEO satellites located at E87.5° and E110.5°,two DGEOs located at E130° and E142°,as well as barometric altimetry as a virtual satellite.Static and dynamic performance tests were completed for the Eastern,the Western,the Northern,the Southern and the Middle regions of China.The evaluation results are as follows:(1) land static test,plane accuracy range:C/A code,15~25m;P code,5~10 meters;altitude accuracy range,1~3 m;(2) land dynamic test,plane accuracy range,C/A code,15~25m;P code,8~10m;(3) velocity accuracy,C/A code,0.13~0.3ms-1,P code,0.15~0.17ms-1;(4) timing accuracy,C/A code,160ns,P code,13 ns;(5) timing compared accuracy of Two Way Satellite Time and Frequency Transfer(TWSTFT),average accuracy,0.068ns;(6) random error of the satellite ranging,10.7 mm;(7) orbit determination accuracy,better than 2 m.The above stated random error is 1σ error.At present,this system is used as a preliminary operational system and a complete system with 3 GEO,3 DGEO and 3 IGSO is being established. | Guo-Xiang Ai Hu-Li Shi Hai-Tao Wu Yi-Hua Yan Yu-Jing Bian Yong-Hui Hu Zhi-Gang Li Ji Guo Xian-De Cai | 2008 | Chinese Journal of Astronomy and Astrophysics2008，8，6： | 33 |
| 2 | Wavelet Analysis of Several Important Periodic Properties in the Relative Sunspot Numbers显示文摘We investigate the wavelet transform of yearly mean relative sunspot number series from 1700 to 2002. The curve of the global wavelet power spectrum peaks at 11-yr, 53-yr and 101-yr periods. The evolution of the amplitudes of the three periods is studied. The results show that around 1750 and 1800, the amplitude of the 53-yr period was much higher than that of the the 11-yr period, that the ca.53-yr period was apparent only for the interval from 1725 to 1850, and was very low after 1850, that around 1750, 1800 and 1900, the amplitude of the 101-yr period was higher than that of the 11-yr period and that, from 1940 to 2000, the 11-yr period greatly dominates over the other two periods. | Gui-MingLe Jia-LongWang | 2003 | Chinese Journal of Astronomy and Astrophysics2003，3，5： | 16 |
| 3 | The Correlation between Gamma-ray and Radio Emissions in γ-ray Loud Blazars显示文摘We collect 119 γ-ray-loud blazars (97 flat spectrum radio quasars (FSRQs) and 22 BL Lacertae objects (BL Lacs)), and investigate possible correlations between their γ-ray emission (maximum, minimum and average values) at 1 GeV and the radio emission at 8.4 GHz. Our main results are as follows. For the lower state γ-ray data, there is no correlation between the γ-ray and radio flux density; For the high state γ-ray data, there are good correlations for the whole 119 blazars and 97 FSRQs, and a weak correlation for the 22 BL Lac objects; For the average γ-ray data, there are good correlations. According to our analysis, we propose that the γ-rays are associated with the radio emission from the jet, and that the γ-ray emission is likely from the SSC process in this case. | Jiang-HeYang Jun-HuiFan | 2005 | Chinese Journal of Astronomy and Astrophysics2005，5，3： | 12 |
| 4 | Gamma-Ray Bursts in the Swift Era显示文摘Since the successful launch of NASA’s dedicated gamma-ray burst (GRB) mission, Swift, the study of cosmological GRBs has entered a new era. Here I review the rapid obser- vational and theoretical progress in this dynamical research field during the first two-year of the Swift mission, focusing on how observational breakthroughs have revolutionized our un- derstanding of the physical origins of GRBs. Besides summarizing how Swift helps to solve some pre-Swift mysteries, I also list some outstanding problems raised by the Swift obser-vations. An outlook of GRB science in the future, especially in the GLAST era, is briely discussed. | Bing Zhang | 2007 | Chinese Journal of Astronomy and Astrophysics2007，7，1： | 11 |
| 5 | Measurements of electronic properties of the Miyun 50m Radio Telescope显示文摘Measurement results of some properties of the Miyun 50m radio telescope (MRT50) of the National Astronomical Observatories, such as pointing calibration, an- tenna beams, system noise temperature, gain and gain variations with elevation are intro- duced. By using a new de-convolution technique developed by our group, the broadening effect on measured beams caused by the width of an extended radio source has been re- moved so that we obtained higher accuracy on the measurements of MRT50 beams. | Xi-Zhen Zhang Xin-Ying Zhu De-Qing Kong Lei Zheng Cheng Yao Hong-Bo Zhang Yan Su Ting-Yi Piao | 2009 | Chinese Journal of Astronomy and Astrophysics2009，9，3： | 11 |
| 6 | Support Vector Machine combined with K-Nearest Neighbors for Solar Flare Forecasting显示文摘A method combining the support vector machine (SVM) the K-Nearest Neighbors (KNN), labelled the SVM-KNN method, is used to construct a solar flare forecasting model. Based on a proven relationship between SVM and KNN, the SVM-KNN method improves the SVM algorithm of classification by taking advantage of the KNN algorithm according to the distribution of test samples in a feature space. In our flare forecast study, sunspots and 10cm radio flux data observed during Solar Cycle 23 are taken as predictors, and whether an M class flare will occur for each active region within two days will be predicted. The SVM- KNN method is compared with the SVM and Neural networks-based method. The test results indicate that the rate of correct predictions from the SVM-KNN method is higher than that from the other two methods. This method shows promise as a practicable future forecasting model. | Rong Li Hua-Ning Wang Han He Yan-Mei Cui Zhan-Le Du | 2007 | Chinese Journal of Astronomy and Astrophysics2007，7，3： | 10 |
| 7 | A New Method of Identifying 3D Null Points in Solar Vector Magnetic Fields显示文摘Employing the Poincaré index of isolated null-points in a vector field,we worked out a mathematical method of searching for 3D null-points in coronal magnetic fields. After introducing the relevant differential topology, we test the method by using the analytical model of Brown & Priest. The location of nullpoint identified by our method coincides precisely with the analytical solution.Finally we apply the method to the 3D coronal magnetic fields reconstructed from an observed MDI magnetogram of a super-active region (NOAA 10488). We find that the 3D null-point seems to be a key element in the magnetic topology associated with flare occurrence. | Hui Zhao Jing-Xiu Wang Jun Zhang Chi-Jie Xiao | 2005 | Chinese Journal of Astronomy and Astrophysics2005，5，5： | 9 |
| 8 | Statistical Properties of a Blazar Sample and Comparison of HBLs, LBLs and FSRQs显示文摘Making use of the 2MASS Data Release, we have searched for nearinfrared (JHK) counterparts to 268 blazars from Donato et al. and obtained 238counterparts within 5' in the area covered by 2MASS. It provides us a sample with infrared data several times larger than the previous one of the same kind.Based on our sample and the sample by Donato et al., we have compared in detail the properties of HBLs, LBLs and FSRQs from five aspects and found that HBLs are significantly different from LBLs and FSRQs while LBLs are not obviously different from FSRQs. Our results strongly support the division of BL Lac objects into the high-frequency peaked (HBL) and low-frequency peaked (LBL) objects introduced by Padovani & Giommi and show that HBLs and LBLs are two kinds of blazar having different physical properties. | Li-Sheng Mao Guang-Zhong Xie Jin-Ming Bai Hong-Tao Liu | 2005 | Chinese Journal of Astronomy and Astrophysics2005，5，5： | 9 |
| 9 | Orbit Determination Using Satellite-to-Satellite Tracking Data显示文摘Satellite-to-Satellite tricking (SST) data can be used to determine the orbits of spacecraft in two ways. One is combined orbit determination, which combines SST data with ground-based tracking data and exploits the enhanced tracking geometry. The other is the autonomous orbit determination, which uses only SST. The latter only fits some particular circumstances since it suffers the rank defect problem in other circumstances. The proof of this statement is presented. The nature of the problem is also investigated in order to find an effective solution. Several. methods of solution are discussed. The feasibility of the methods is demonstrated by their application to a simulation. | Ying-ChunLiu LinLiu | 2001 | Chinese Journal of Astronomy and Astrophysics2001，1，3： | 9 |
| 10 | On the Physical Processes in Contact Binary Systems显示文摘Three importantphysical processes occurringin contact binarysystems are studied. The first one is the effect of spin, orbital rotation and tide on the structure of the components, which includes also the effect of meridian circulation on the mixing of the chemical elements in the components. The second one is the mass and energy exchange between the components. To describe the energy exchange, a new approach is introduced based on the understanding that the exchange is due to the release of the potential, kinetic and thermal energy of the exchanged mass. The third is the loss of mass and angular momentum through the outer Lagrangian point. The rate of mass loss and the angular momentum carried away by the lost mass are discussed. To show the effects of these processes, we follow the evolution of a binary system consisting of a 12M and a 5M star with mass exchange between the components and mass loss via the outer Lagrangian point, both with and without considering the effects of rotation and tide. The result shows that the effect of rotation and tide advances the start of the semi-detached and the contact phases, and delays the end of the hydrogen-burning phase of the primary. Furthermore, it can change not only the occurrence of mass and angular momentum loss via the outer Lagrangian point, but also the contact or semi-contact status of the system. Thus, this effect can result in the special phenomenon of short-term variations occurring over a slow increase of the orbital period. The occurrence of mass and angular momentum loss via the outer Lagrangian point can affect the orbital period of the system significantly, but this process can be influenced, even suppressed out by the effect of rotation and tide. The mass and energy exchange occurs in the common envelope. The net result of the mass exchange process is a mass transfer from the primary to the secondary during the whole contact phase. | Run-Qian Huang Han-Feng Song Shao-Lan Bi | 2007 | Chinese Journal of Astronomy and Astrophysics2007，7，2： | 8 |
| 11 | The Prediction of Maximum Amplitudes of Solar Cycles and the Maximum Amplitude of Solar Cycle 24显示文摘We present a brief review of predictions of solar cycle maximum ampli-tude with a lead time of 2 years or more. It is pointed out that a precise predictionof the maximum amplitude with such a lead-time is still an open question despiteprogress made since the 1960s. A method of prediction using statistical character-istics of solar cycles is developed: the solar cycles are divided into two groups, ahigh rising velocity (HRV) group and a low rising velocity (LRV) group, dependingon the rising velocity in the ascending phase for a given duration of the ascendingphase. The amplitude of Solar Cycle 24 can be predicted after the start of thecycle using the formula derived in this paper. Now, about 5 years before the startof the cycle, we can make a preliminary prediction of 83.2-119.4 for its maximumamplitude. | Jia-Long Wang, Jian-Cun Gong, Si-Qing Liu, Gui-Ming Le and Jing-Lan Sun1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 1000122 Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080 | 2002 | Chinese Journal of Astronomy and Astrophysics2002，2，6： | 8 |
| 12 | Gamma-Ray Bursts: Afterglows and Central Engines显示文摘Gamma-ray bursts (GRBs) are the most intense transient gamma-ray events in the sky; this, together with the strong evidence (the isotropic and inhomogeneous distribution of GRBs detected by BASTE) that they are located at cosmological distances, makes them the most energetic events ever known. For example, the observed radiation energies of some GRBs are equivalent to the total convertion into radiation of the mass energy of more than one solar mass. This is thousand times stronger than the energy of a supernova explosion. Some unconventional energy mechanism and extremely high conversion efficiency for these mysterious events are required. The discovery of host galaxies and association with supernovae at cosmological distances by the recently launched satellite of BeppoSAX and ground based radio and optical telescopes in GRB afterglow provides further support to the cosmological origin of GRBs and put strong constraints on their central engine. It is the aim of this article to review the possible central engines, energy mechanisms, dynamical and spectral evolution of GRBs, especially focusing on the afterglows in multi-wavebands. | K.S.Cheng T.Lu | 2001 | Chinese Journal of Astronomy and Astrophysics2001，1，1： | 8 |
| 13 | Fitting formulae for the effects of binary interactions on lick indices and colors of stellar populations显示文摘More than about 50% of stars are in binaries, but most stellar populationstudies take single star stellar population (ssSSP) models, which do not take binary interactions into account. In fact, the integrated peculiarities of ssSSPs are different from those of stel- lar populations with binary interactions (bsSSPs). Therefore, it is necessary to investigate the effects of binary interactions on the Lick indices and colors of populations in detail. We show some formulae for calculating the difference between the Lick indices and col- ors of bsSSPs, and those of ssSSPs. Twenty-five Lick indices and 12 colors are studied in this work. The results can be conveniently used for calculating the effects of binary interactions on stellar population studies and for adding the effects of binary interactions into present ssSSP models. The electronic data and fortran procedures in the paper can be obtained on request from the authors. | Zhong-Mu Li Zhan-Wen Han | 2009 | Chinese Journal of Astronomy and Astrophysics2009，9，2： | 7 |
| 14 | Estimating the Size and Timing of the Maximum Amplitude of Solar Cycle 24显示文摘A simple statistical method is used to estimate the size and timing of maximum amplitude of the next solar cycle (cycle 24). Presuming cycle 23 to be a short cycle (as is more likely), the minimum of cycle 24 should occur about December 2006 (±2 months) and the maximum, around March 2011 (±9 months),and the amplitude is 189.9 ± 15.5, if it is a fast riser, or about 136, if it is a slow riser. If we presume cycle 23 to be a long cycle (as is less likely), the minimum of cycle 24 should occur about June 2008 (±2 months) and the maximum, about February 2013 (±8 months) and the maximum will be about 137 or 80, according as the cycle is a fast riser or a slow riser. | Ke-Jun Li Peng-Xin Gao Tong.Wei Su | 2005 | Chinese Journal of Astronomy and Astrophysics2005，5，5： | 7 |
| 15 | A New Feature Vector Using Selected Line Spectra for Pulsar Signal Bispectrum Characteristic Analysis and Recognition显示文摘Average pulse profiles of pulsar signals are analyzed using the bispectrum tech-nique. The result shows that there are nonlinear phase couplings between the two frequency axes of the bispectrum charts, which indicate nonlinear factors in the generation and prop-agation of pulsar signals. Bispectra can be used as feature vectors of pulsar signals because of their being translation invariant. A one-dimension selected line spectrum algorithm for ex-tracting pulsar signal characteristic is proposed. Compared with selected bispectra, the pro-posed selected line spectra have the maximum interclass separability measurements from the point of view of the whole one-dimension feature vector. Recognition experiments on several pulsar signals received at several frequency bands are carried out. The result shows that the selected line spectrum algorithm is suitable for extracting pulsar signal characteristics and has a good classification performance. | Zhen-Hua Xie Lu-Ping XU Guang-Ren Ni Yan Wang | 2007 | Chinese Journal of Astronomy and Astrophysics2007，7，4： | 7 |
| 16 | Wavelet Analysis of the Schwabe Cycle Properties in Solar Activity显示文摘Properties of the Schwabe cycles in solar activity are investigated by using wavelet transform. We study the main range of the Schwabe cycles of the solar activity recorded by relative sunspot numbers, and find that the main range of the Schwabe cycles is the periodic span from 8-year to 14-year. We make the comparison of 11-year's phase between relative sunspot numbers and sunspot group numbers. The results show that there is some difference between two phases for the interval from 1710 to 1810, while the two phases are almost the same for the interval from 1810 to 1990. | Gui-Ming LeNational Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 Center for Space Science and Applied Research Center, Chinese Academy of Sciences, Beijing 100080 | 2004 | Chinese Journal of Astronomy and Astrophysics2004，4，6： | 7 |
| 17 | Verification of a Similar Cycle Prediction for the Ascending and Peak Phases of Solar Cycle 23显示文摘Reviews of long-term predictions of solar cycles have shown that a precise prediction with a lead time of 2 years or more of a solar cycle remains an unsolved problem.We used a simple method,the method of similar cycles,to make long-term predictions of not only the maximum amplitude but also the smoothed monthly mean sunspot number for every month of Solar Cycle 23.We verify and compare our prediction with the latest available observational results. | Jia-Long Wang Jian-Cun Gong 等 | 2002 | Chinese Journal of Astronomy and Astrophysics2002，2，5： | 6 |
| 18 | A Study of Binary Stellar Population Synthesis of Elliptical Galaxies显示文摘We determined the relative stellar ages and metallicities of about 80 elliptical galaxies in both low and high density environments using the latest binary stellar population (BSP) synthesis model and tested the predictions of a recent hierarchical formation model that adopted the new ACDM cosmology. The stellar ages and metallicities were estimated from two high-quality published spectra line indices, the Hβand [MgFe] indices. The results show that the stellar populations of elliptical galaxies are older than 3.9 Gyr and more metal rich than 0.02. Most of our results are in agreement with the model predictions: (1) elliptical galaxies in denser environment are redder and have older populations than field galaxies; (2) elliptical galaxies with more massive stellar components are redder and have older and more metal rich populations than less massive ones; (3) the most massive galaxies have the oldest and most metal rich stars. However, some of our results differ from the model predictions on the metallicity distributions of low- and high-density elliptical galaxies and the dependence on the distance to the cluster center. | Zhong-Mu Li Feng-Hui Zhang Zhan-Wen Han | 2006 | Chinese Journal of Astronomy and Astrophysics2006，6，6： | 6 |
| 19 | Optical Design of Multilayer Achromatic Waveplate by Simulated Annealing Algorithm显示文摘我们使用了一个蒙特卡罗方法—模仿的退火的算法—执行多层的无色波浪板的设计。我们三的现在的解决方案 -- ,六层、十层的无色波浪盘子。优化 retardance 背景被发现是 89 ° 5 1'39''± 0 ° 3 3'37'' 和 89 ° 5 为六层、十层的波浪盘子的 4'46''± 0 ° 2 2'4'' 分别地,从 1000 nm 为波长到 1800 nm。多层的波浪盘子的测定偏振的性质基于几个数字实验被调查。与以前建议的三层的无色波浪板相对照,新六层、十层的无色波浪板的快轴在固定角度留下,独立于波长。多层的无色波浪板的二个应用程序被讨论,在大熊的红外线的成像磁针自记仪(IRIM ) 系统的通用阶段 shifter 和双折射的过滤器太阳的天文台(BBSO ) 。我们也检查了一个试验性的方法测量波浪盘子的 retardance。 | Jun Ma Jing-Shan Wang Carsten Denker Hai-Min Wang | 2008 | Chinese Journal of Astronomy and Astrophysics2008，8，3： | 6 |
| 20 | The Effect of Solar Activity on the Annual Precipitation in the Beijing Area显示文摘Using continuous wavelet transform, we examine the relationship between solar activity and the annual precipitation in the Beijing area. The results indicate that the annual precipitation is closely related to the variation of sunspot numbers, and that solar activity probably plays an important role in influencing the precipitation on land. | JuanZhao Yan-BenHan Zhi-AnLi | 2004 | Chinese Journal of Astronomy and Astrophysics2004，4，2： | 6 |
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