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A Check on the Variations of Earth's Rotation with an Ancient Solar Eclipse

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chinese Journal of Astronomy and Astrophysics 2003年第6期3卷 569-575页

作者： Yan-Ben han and Qi-Yuan Qiao national astronomical observatories, chinese academy of sciences, beijing 100012 national astronomical observatories Chinese Academy of Sciences Beijing 100012

We address the relation between an ancient total eclipse, which occurred on A.D.1542 August 11 and the variation of Earth's rotation. The total eclipse was recorded in some ancient chinese books, especially in local chronicles. Some of the documents include useful information for determining the location of the totality zone. The parameters of the eclipse are calculated by using the DE406 Ephemeris. A high-precision value of ΔT which expresses the variation of the Earth's rotation, of about 300 ~ 380 s, is obtained.

关键词： solar eclipse earth rotation

“Double dawn”eclipse and the rotational variation of the earth

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chinese Science Bulletin 2000年第11期45卷 988-991页

作者： ZhanG Peiyu & han Yanben1. Purple Mountain observatory, chinese academy of sciences, Nanjing 210008, china 2. beijing astronomical observatory, chinese academy of sciences, beijing 100012, national astronomical observatory, chinese academy of sciences, beijing 100012, china Purple Mountain observatory Chinese Academy of Sciences Nanjing China beijing astronomical observatory Chinese Academy of Sciences Beijing national astronomical observatory Chinese Academy of Sciences Beijing China

A record of 'double dawn' at State Zheng in the first year of the reign of King Yi in Western Zhou Dynasty in the chronicle 'Bamboo Annals' (Zhushu Jinian) is discussed. We think that it may be a record of an annular solar eclipse happening in 899 BC. The record and the AT, which describes the secular variation of the earth’s rotation, are analyzed and discussed.

关键词： solar eclipse earth’s rotation.

Pulsars in FIRST Observations

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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 observatories, chinese academy of sciences, beijing 100012 national astronomical observatories 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 J1022+1001, J1518+4904, J1652+2651, and proper motion upper limits of PSR J0751+1807, J1012+5307, and J1640+2224. The proper motions of the other ten pulsars are consistent with the catalog values.

关键词： pulsar: general -stars: neutron

chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation

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Journal of Geriatric Cardiology 2024年第3期21卷 251-314页

作者： Chang-Sheng MA Shu-Lin WU Shao-Wen LIU Ya-Ling han chinese Society of Cardiology chinese Medical Association Heart Rhythm Committee of chinese Society of Biomedical Engineering beijing Anzhen Hospital Capital Medical University Guandong Provincial People’s Hospital Shanghai First People’s Hospital General Hospital of Northern Theater Command 不详

Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia,significantly impacting patients’quality of life and increasing the risk of death,stroke,heart failure,and *** the past two decades,there have been significant breakthroughs in AF risk prediction and screening,stroke prevention,rhythm control,catheter ablation,and integrated *** this period,the scale,quality,and experience of AF management in china have greatly improved,providing a solid foundation for the development of guidelines for the diagnosis and management of *** further promote standardized AF management,and apply new technologies and concepts to clinical practice in a timely and comprehensive manner,the chinese Society of Cardiology of the chinese Medical Association and the Heart Rhythm Committee of the chinese Society of Biomedical Engineering have jointly developed the chinese Guidelines for the Diagnosis and Management of Atrial *** guidelines have comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2-VASc-60 stroke risk score based on the characteristics of AF in the Asian *** guidelines have also reevaluated the clinical application of AF screening,emphasized the significance of early rhythm control,and highlighted the central role of catheter ablation in rhythm control.

关键词： prevention sustained diagnosis

Wavelet analysis of sunspot relative numbers

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chinese Science Bulletin 2002年第7期47卷 609-612页

作者： han Yanben & han Yonggangnational astronomical observatories, chinese academy of sciences, beijing 100012, china Department of Applied Mathematics, beijing Polytechnic University, beijing 100022, china 1. national astronomical observatories Chinese Academy of Sciences 100012 Beijing China 2. Department of Applied Mathematics Beijing Polytechnic University 100022 Beijing China

The time series of the monthly smoothed sun-spot numbers in 1749-2000 is analyzed with the wavelet. The result shows that besides the known time-variation of the period about 11 years, other main periods of the sunspot numbers, such as the periods of about 100 years and so on, vary with time. We suggest that the time-variation of the main periods is the manifestation of the complex variation of sunspot numbers. It is significant to make a thorough study of the character and mechanism of the time-variation of the periods for proving prediction of sunspot numbers, especially for understanding the variation process of sunspot numbers.

关键词： sunspot numbers prediction wavelet time-variation.

Possible effect of solar activity on variation of the tree-rings of a 500 a platycladus orientalis at the Mausoleum of Emperor Huang

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Science china(Physics,Mechanics & Astronomy) 2009年第4期52卷 631-639页

作者： FENG Bo1,2 & han YanBen1 1 Xi’an Institute of Posts & Telecommunications,Xi’an 710061,china 2 national astronomical observatories,chinese academy of sciences,beijing 100012,china Xi’an Institute of Posts & Telecommunications Xi’an 710061 China national astronomical observatories Chinese Academy of Sciences Beijing 100012 China

The variation of the tree-ring's index of a platycladus orientalis at the Mausoleum of Emperor Huang and of a long series of sunspots relative number during AD1470-1974 are analyzed by using the wavelet power spectrum method,and their variation characters are also discussed. It is determined that the tree-ring's variation has cycles of approximate 2-7,11,93 and 150 a. Two data series are used for analyzing sunspot relative number(SSN) variation. First,the analysis of the annual average SSN during AD1700-1974 proved that variation cycles are about 11,50,and 93 a; then,the data during AD1465-1975 obtained from the decadal average SSN train over 7000 a reconstructed on the geomagnetic data is analyzed and its variation cycles are about 50,90,and 160 a. Besides the tree-rings cycle of 2-7 a is commonly considered to be related to ENSO,while 11 a cycle is related to solar Schwabe cycle; in addition,it is possible that the cycles of 90 and150 a are likely to be related to solar Gleissberg cycle and Suess cycle. The correlations between them are possibly due to the effect of solar activity on the climate and additionally on the tree's growth.

关键词： tree-ring solar activity climate change wavelet spectrum

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.

A new method of ionospheric-free hybrid differential positioning based on a double-antenna CAPS receiver

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Science china(Physics,Mechanics & Astronomy) 2009年第3期52卷 368-375页

作者： GUO JinYun1,2, han YanBen1 & ChanG XiaoTao3 1 national astronomical observatories, chinese academy of sciences, beijing 100012, china 2 College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266510, china 3 chinese academy of Surveying and Mapping, beijing 100039, china 1. national astronomical observatories Chinese Academy of Sciences Beijing 100012 China 2. College of Geodesy and Geomatics Shandong University of Science and Technology Qingdao 266510 China 3. chinese academy of Surveying and Mapping Beijing 100039 China

chinese Area Positioning System (CAPS) is a transmitted satellite navigation system moved by the chinese academy of sciences. Three basic modes of navigation and positioning with CAPS are given, and then a comparative analysis is made in this paper. In terms of the principle that the ionospheric delay is at an inverse ratio to the frequency square, a new ionospheric-free positioning method based on a double-antenna CAPS receiver is put forward. Then the hybrid differential observations and the solving equations and algorithms for one epoch and multi epochs are deduced according to the basic principle of the method. The method may remove the global errors in signal emission, propagation, transmission and receiving (e.g., ionospheric delay, hardware delay, and clock error). So it is very convenient for the single-epoch solution and multi-epoch navigation and positioning, and may efficiently improve the precision of real time CAPS navigation. Furthermore, the method can be used not only for the geometric orbit determination of CAPS GEO and IGSO satellites and the navigation and positioning, but also for the estimation of the tropospheric zenith delay, which is useful for the study of water vapor changes in the atmosphere. Polynomials are used in this method to express the tropospheric zenith delay and CAPS satellite orbits within the limited time interval, which reduces the num- ber of unknown parameters and thus speeds the computation.

关键词： chinese Area Positioning System (CAPS) ionospheric-free linear combination double-antenna receiver hybrid differential positioning method

Atmospheric Excitation of Time Variable Length-of-Day on Seasonal Scales

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chinese Journal of Astronomy and Astrophysics 2006年第1期6卷 120-124页

作者： Li-Hua Ma Yan-Ben han national astronomical observatories Chinese Academy of Sciences Beijing 100012

We use the method of wavelet transform to analyze the time series of the Earth＇s rotation rate of the EOP （IERS） C04. The result shows that the seasonal （annual and semiannual） variation of the length-of-day （LOD） has temporal variability in its period length and amplitude. During 1965.0-2001.0, the periods of the semiannual and annual components varied mainly from 175-day to 190-day and from 360-day to 370-day, respectively; while their amplitudes varied by more than 0.2 ms and 0.1 ms, respectively. Analyzing the axial component of atmospheric angular momentum （AAM） during this period, we have found that time-variations of period lengths and amplitudes also exist in the seasonal oscillations of the axial AAM and are in good consistency with those of the seasonal LOD change. The time variation of the axial AAM can explain largely the change of the LOD on seasonal scales.

关键词： Earth rotation -- seasonal variation -- wavelet transform