A New Solar Radio Spectrometer at 1.10-2.06 GHz and First Observational Results   总被引：1，自引：0，他引：1  

Hui-Rong Ji  Qi-Jun Pu  Yi-Hua Yan  Yu-Ying Liu  Zhi-Jun Chen  Cheng-Ming Tan  Cong-Ling Cheng  De-Bang Lao  Shu-Ke Li  Zhi-Qiang Wang  Min-Hong Yu  Jian-Nong Liu  Li-Kang Zhang  Ji-Yong Gao National Astronomical Observatories  Chinese Academy of Sciences  Beijing  Hebei Semiconductor Research Institute  Shijiazhuang 《中国天文和天体物理学报》2005,5(4):433-441

An improved Solar Radio Spectrometer working at 1.10-2.06 GHz with much improved spectral and temporal resolution, has been accomplished by the National Astronomical Observatories and Hebei Semiconductor Research Institute, based on an old spectrometer at 1-2 GHz. The new spectrometer has a spectral resolution of 4 MHz and a temporal resolution of 5ms, with an instantaneous detectable range from 0.02 to 10 times of the quiet Sun flux. It can measure both left and right circular polarization with an accuracy of 10% in degree of polarization. Some results of preliminary observations that could not be recorded by the old spectrometer at 1-2 GHz are presented.  相似文献   

X-ray synchrotron emission from the oblique shock in the jet of the powerful radio galaxy 3C 346     

D. M. Worrall  M. Birkinshaw 《Monthly notices of the Royal Astronomical Society》2005,360(3):926-934

We report the first detection, with Chandra , of X-ray emission from the jet of the powerful narrow-line radio galaxy 3C 346. X-rays are detected from the bright radio and optical knot at which the jet apparently bends by approximately 70°. The Chandra observation also reveals a bright galaxy-scale atmosphere within the previously known cluster and provides a good X-ray spectrum for the bright core of 3C 346. The X-ray emission from the knot is synchrotron radiation, as seen in lower-power sources. In common with these sources, there is evidence of morphological differences between the radio/optical and X-ray structures, and the spectrum is inconsistent with a one-component continuous-injection model. We suggest that the X-ray-bright knot is associated with a strong oblique shock in a moderately relativistic, light jet, at ∼ 20° to the line of sight, and that this shock is caused by the jet interacting with the wake in the cluster medium behind the companion galaxy of 3C 346. The general jet curvature can result from pressure gradients in the cluster atmosphere.  相似文献   

Ⅰ型超新星模型——部分燃尽白矮星     

李宗伟  J.C.Wheeler 《中国天文和天体物理学报》1986,(3)

本文用完全动力学程式计算了Ⅰ型超新星爆发。这些模型是依据氦或碳和氧构成星核,部分地或全部地产生瞬时完成的核燃烧。计算中将动力学方程、核统计平衡、Rayleigh-Taylor不稳定性等物理过程联合起来求解。重点比较了Rayleigh-Taylor不稳定性的影响,现不能作出完全肯定的结论。计算结果列在表1、表2和图2—6中。  相似文献   

形变大地测量学的进展、问题与地震预报   总被引：12，自引：7，他引：5  

周硕愚  吴云  李正媛  杜瑞林 《大地测量与地球动力学》2004,24(4):95-101

简要概括了形变大地测量学的革命性进展，研讨了它的科学特色、功能和定义以及对地球科学和防灾减灾的推动。形变大地测量学有助于从根本上击破多年来制约地震预报的“瓶颈”，但也存在不少急待解决的问题。着重研讨了在21世纪前10年，形变大地测量学如何依托多年的学科积累并充分受益于人造卫星和数字化等新技术，开展创新性研究和试验以推进地震预报。为此，对当前的研究工作提出了12条科学技术途径。最后对学科名称提出了建议。  相似文献   

胶辽鲁西徐淮地区新元古代地层多重划分对比          下载免费PDF全文

许克民  王来明  刘桂玲  张增奇  汪又平  胡艳蕾 《山东国土资源》2004,20(5):26-31,36

依据岩性组合、古生物特征及地震事件层研究，对胶辽鲁西徐淮地区新元古代地层可作如下多重划分对比：鲁西黑山官组、二青山组分别与辽东的钓鱼台组，南芬组相当，胶东豹山口组可与南芬组对比，它们同属青白口系。辽东南关岭组下部、鲁西石旺庄组下部、苏皖北部贾园组、淮南九里桥组皆为一套砂灰岩组合，都发育第一期地震事件层，并开始含有后生动物化石，为等时地层单位，与其以上各前寒武岩石地层单位同属灯影峡阶，鲁西的佟家庄组、浮来山组可分别与辽东桥头组、长岭子组、胶东辅子夼组、南庄组、苏皖北部兰陵组一城山组、淮南伍山组一四十里长山组对比，归属《中国区域年代地层(地质年代)表》新划分的陡山陀阶。  相似文献   

The Latest Research Progress on El Nino     

CHEN Dianyou  WANG Ruiting  WANG Xudong 《世界地质(英文版)》2002,5(1)

Cold water in the deep Pacific can be drawn up to the surface (or west warm water drifts eastwards ) because strong tide increases the mixing of seawater both in vertical and horizontal. In this way greenhouse effect is decreased or increased by means of absorbing (or releasing) CO2. Therefore, La Nina cold event (or El Nino warm event) may occur,which is caused by wanning - up or cooling - down air above the ocean. Volcanic action at sea bottom is also controlled by strong tide.  相似文献   

Is there a disc in the superluminal quasars?     

E. Rokaki  A. Lawrence  F. Economou  A. Mastichiadis 《Monthly notices of the Royal Astronomical Society》2003,340(4):1298-1308

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The 550-au Mission: a critical discussion     

S. G. Turyshev  B-G. Andersson 《Monthly notices of the Royal Astronomical Society》2003,341(2):577-582

We have studied the science rationale, goals and requirements for a mission aimed at using the gravitational lensing from the Sun as a way of achieving high angular resolution and high signal amplification. We find that such a mission concept is compromised by several practical problems. Most severe are the effects due to the plasma in the solar atmosphere which cause refraction and scattering of the propagating rays. These effects either limit the frequencies that can be observed to those above ∼1 THz, or they move the optical point outwards beyond the vacuum value of ≥550 au. (Thus for observing frequency of 300 GHz the optical point is moved outwards to ∼ 680 au.) Density fluctuations in the inner solar atmosphere will further cause random pathlength differences for different rays. The corrections for the radiation from the Sun itself will also be a major challenge at any wavelength used, but could be mitigated with coronographic techniques. Given reasonable constraints on the spacecraft (particularly in terms of size and propulsion), source selection as well as severe navigational constraints further add to the difficulties for a potential mission. Nevertheless, unbiased surveys of small-scale structure on the sky at short wavelengths might be the most promising application of such a mission.  相似文献   

The intracluster iron distribution around 4C+55.16     

K. Iwasawa  A.C. Fabian  S.W. Allen  S. Ettori 《Monthly notices of the Royal Astronomical Society》2001,328(1):L5-L10

We report on the metal distribution in the intracluster medium around the radio galaxy 4C+55.16     observed with the Chandra X-ray Observatory . The radial metallicity profile shows a dramatic change at 10 arcsec (∼50 kpc) in radius from half solar to twice solar at inner radii. Also found was a plume-like feature located at ∼3 arcsec to the south-west of the centre of the galaxy, which is mostly accounted for by a strong enhancement of iron L emission. The X-ray spectrum of the plume is characterized by the metal abundance pattern of Type Ia supernovae (SNeIa), i.e. large ratios of Fe to α elements, with the iron metallicity being unusually high at     solar (90 per cent error). How the plume has been formed is not entirely clear. The inhomogeneous iron distribution suggested in this cluster provides important clues to understanding the metal enrichment process of the cluster medium.  相似文献   

概率赋范空间的S-凸和K-凸     

张敏先 《成都信息工程学院学报》2001,16(3):209-212

文献[1][2]认为M－PN空间是局部凸的。通过定理说明这个结论对t-模T（a,b)≥min(a,b)时成立。又通过反例表明，当t-模型T（a,b)=max(a b-1,0）时无论邻域Nθ（ε，λ）概率有界还是概率半有界结论均不成立。还讨论了Takahashi凸性并对S－凸和K－凸作了比较。  相似文献