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501.
Different attenuation correction methods for the X-band dual linear polarimetric radar are analyzed in this paper.The specific differential phase shift K DP is always considered as an effective factor in radar signal attenuation correction.However,the values of K DP for light rains are too small,which results in unstable quality and large errors of rainfall estimation.Therefore,radar horizontal reflectivity Z H and specific differential phase shift are combined together in the Z H –K DP method to correct th... 相似文献
502.
Using the Joint Typhoon Warning Center (JTWC) optimal typhoon tracks data and the NCEP/NCAR reanalysis,an investigation is made on the summer Asian-Pacific Oscillation (APO) in relation to synchronous air circulation from the coastal waters of East Asia to western North Pacific (WNP),along with a further exploration on the relationship between the APO and the tropical cyclone (TC) activities over the coastal waters of China.The results show that there exists a strong correlation between the APO intensity an... 相似文献
503.
Ground-based measurements are essential for understanding alpine glacier dynamics,especially in remote regions where in-situ measurements are extremely limited.Prom 1 May to 22 July 2005(the spring-summer period),and from 2 October 2007 to 20 January 2008(the autumn-winter period),surface radiation as well as meteorological variables were measured over the accumulation zone on the East Rongbuk Glacier of Mt. Qomolangma/Everest at an elevation of 6560 m a.s.l.by using an automatic weather station(AWS).The... 相似文献
504.
Jarken Esimbek 《中国天文和天体物理学报》2011,(2)
We report results of the H2CO and H110α survey toward 281 UCHII regions using the Urumqi 25m radio telescope.We obtained 37 new H2CO detections,and H110α was simultaneously detected in eight of them.Only H110α was detected in another UCHII region.We calculated kinematic distances of nine UCHII regions with the detected H110α and resolved the kinematic distance ambiguity for six of them.The detection rate of H2CO of our observation was 13.2%,which is low compared with one of the other authors.The possible re... 相似文献
505.
Li-Hong Yan Jian-Cheng Wang Yunnan Observatory /National Astronomical Observatories Key Laboratory for the Structure Evolution of Celestial Objects Chinese Academy of Sciences Kunming China Graduate School of Chinese Academy of Sciences Beijing China 《中国天文和天体物理学报》2011,(6)
We present a new explanation for the origin of the steep power-law(SPL) state of X-ray binaries.The power-law component of X-ray emission is the synchrotron radiation of relativistic electrons in highly magnetized compact spots orbiting near the inner stable circular orbit of a black hole.It has a hard spectrum that extends to above MeV energies,which is determined by the electron acceleration rate.These photons are then down-scattered by the surrounding plasma to form an observed steep spectrum.We discuss ... 相似文献
506.
Daniel Okoh 《中国天文和天体物理学报》2011,(6)
A 30-m TeraHertz(THz) radio telescope is proposed to operate at 200 μm with an active primary surface.This paper presents sensitivity analysis of active surface panel positioning errors with optical performance in terms of the Strehl ratio.Based on Ruze's surface error theory and using a Monte Carlo simulation,the effects of six rigid panel positioning errors,such as piston,tip,tilt,radial,azimuthal and twist displacements,were directly derived.The optical performance of the telescope was then evaluated usi... 相似文献
507.
Xiang-Yun Fu Pu-Xun Wu Hong-Wei Yu Zheng-Xiang Li Institute of Physics Hunan University of Science Technology Xiangtan China Center for Nonlinear Science 《中国天文和天体物理学报》2011,(8)
We test the distance-duality(DD) relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al.(the elliptical β model) and Bonamente et al.(the spherical β model),and the luminosity distance DL from Constitution and Union2 type Ia supernova(SNe Ia) datasets. To obtain DL associated with the observed DA at the same redshift,we smooth the noise of the SNe Ia in a model-independent way,obtain the evolutionary curve of DL and,finally,test the DD rel... 相似文献
508.
Xiao-Yan Gao Jian-Cheng Wang Ming Zhou National Astronomical Observatories /Yunnan Observatories Chinese Academy of Sciences Kunming China Key Laboratory for the Structure Evolution of Celestial Objects China Graduate University of Chinese Academy of Sciences Beijing China 《中国天文和天体物理学报》2011,(8)
The external Compton(EC) model is used to study the high energy emission of some blazars,in which the external photon field is considered to dominate inverse Compton radiation. We explore the properties of the external photon field through analyzing the FERMI LAT bright AGN sample within three months of the start of operations in sky-survey mode. In the sample,assuming the high energy radiation of low synchrotron peaked blazars is from the EC process,we find that the external photon parameter Uext/νext may ... 相似文献
509.
Shi-Bi Pu Zhan-Wen Han National Astronomical Observatory /Yunnan Observatory Chinese Academy of Sciences Kunming China Graduate University of Chinese Academy of Sciences Beijing China Key Laboratory of the Structure Evolution of Celestial Objects China 《中国天文和天体物理学报》2011,(8)
We present high quality long slit spectra along the major and minor axes out to 1.5 effective radii of the massive galaxy NGC 4636 taken by the Hobby-Eberly Telescope. Using the Fourier Correlation Quotient method,we measured the stellar line-of-sight velocity distribution along the axes. Furthermore,six Lick/IDS indices(Hβ,Mgb,Fe5015,Fe5270,Fe5335,Fe5406) are derived from the clean spectrum. By comparing the measured absorption line strengths with the predictions of Simple Stellar Population(SSP) models,we... 相似文献
510.
Hong Qi Da-Ming Chen National Astronomical Observatories Chinese Academy of Sciences Beijing China 《中国天文和天体物理学报》2011,(9)
We study the statistics of large-separation multiply-imaged quasars lensed by clusters of galaxies.In particular,we examine how the observed brightest cluster galaxies (BCGs) affect the predicted numbers of wide-separation lenses.We model the lens as an NFW-profiled dark matter halo with a truncated singular isothermal sphere to represent the BCG in its center.We mainly make predictions for the Sloan Digital Sky Survey Quasar Lens Search (SQLS) sample from the Data Release 5 (DR5) in two standard ΛCDM cosmo... 相似文献