Star formation in blue compact dwarf galaxies: Mkn 104 and I Zw 97     

S. Ramya  D. K. Sahu  T. P. Prabhu 《Monthly notices of the Royal Astronomical Society》2009,396(1):97-108

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Surface magnetic fields on two accreting T Tauri stars: CV Cha and CR Cha     

G. A. J. Hussain  A. Collier Cameron  M. M. Jardine  N. Dunstone  J. Ramirez Velez  H. C. Stempels  J.-F. Donati  M. Semel  G. Aulanier  T. Harries  J. Bouvier  C. Dougados  J. Ferreira  B. D. Carter  W. A. Lawson 《Monthly notices of the Royal Astronomical Society》2009,398(1):189-200

We have produced brightness and magnetic field maps of the surfaces of CV Cha and CR Cha: two actively accreting G- and K-type T Tauri stars in the Chamaeleon I star-forming cloud with ages of 3–5 Myr. Our magnetic field maps show evidence for strong, complex multipolar fields similar to those obtained for young rapidly rotating main-sequence stars. Brightness maps indicate the presence of dark polar caps and low-latitude spots – these brightness maps are very similar to those obtained for other pre-main-sequence and rapidly rotating main-sequence stars.
Only two other classical T Tauri stars have been studied using similar techniques so far: V2129 Oph and BP Tau. CV Cha and CR Cha show magnetic field patterns that are significantly more complex than those recovered for BP Tau, a fully convective T Tauri star.
We discuss possible reasons for this difference and suggest that the complexity of the stellar magnetic field is related to the convection zone; with more complex fields being found in T Tauri stars with radiative cores (V2129 Oph, CV Cha and CR Cha). However, it is clearly necessary to conduct magnetic field studies of T Tauri star systems, exploring a wide range of stellar parameters in order to establish how they affect magnetic field generation, and thus how these magnetic fields are likely to affect the evolution of T Tauri star systems as they approach the main sequence.  相似文献   

基于SVAR模型的气温变化对南京市工业经济的影响研究   总被引：7，自引：1，他引：6  

孙宁  李廉水 《气象》2009,35(10):90-96

目前气象经济学领域探讨气象因子与经济体之间相互动态影响的研究尚不多见,基于此,采用年平均气温序列及工业产值、GDP、劳动力序列,建立多变量的结构向量自回归模型(SVAR模型),通过脉冲响应函数来考察气温对南京市工业经济的动态影响,并用方差分解法揭示其相互影响程度.结果表明总体上气温升高对南京工业有负面影响,但是这种负面作用是趋缓的,平均每年南京工业产值的3.1%受到气温升高带来的负面影响;同时南京工业经济发展对当地气温升高确实存在促进作用,平均每年南京工业经济发展对本地的气温升高的贡献率有4.4%.研究也说明SVAR模型不失为研究气象因子对经济体影响的可行方法.  相似文献   

雷达定量降水估算在水文模式汛期洪水预报中的应用试验   总被引：3，自引：0，他引：3  

彭涛  宋星原  殷志远  沈铁元  李武阶 《气象》2010,36(12):50-55

通过雷达测雨技术获得高时空分辨率的降雨信息,作为水文模型的输入,用以提高水文预报的精度。文章以湖北省白莲河流域为例,利用分组Z-I关系转化雷达反射率为雨强,运用地面雨量站网实测雨量对其进行校准,将不同方法估算得到的雨量结果输入新安江模型进行洪水预报测试,结果表明未校准雷达估算降雨量直接输入水文模型,其结果是不理想的;利用校准后的雷达估算降雨量进行洪水预报,精度得到了很大提高。  相似文献   

塔中Ⅰ号坡折带上奥陶统成礁背景分析   总被引：6，自引：1，他引：5  

王振宇  孙崇浩  张云峰  韩剑发  李新生  吉云刚 《沉积学报》2010,28(3):525-533

自塔中Ⅰ号坡折带上奥陶统良里塔格组发现生物礁滩作为重要储集层后,有关礁的形态和规模一直存在较大的争议。本研究解析该地区礁的古生物组合、古生态结构和沉积环境,以此为基础系统论证生物礁的沉积序列。礁的建造方式可归属于珊瑚骨架礁丘、层孔虫—海绵骨架礁丘、海绵—层孔虫骨架礁丘以及管孔藻—层孔虫骨架礁丘几种生态类型,这些骨架礁丘无论从造礁生物多样性、生态组合特征以及造礁规模,皆不同于前时代的前寒武纪叠层石礁、寒武纪古杯礁、早奥陶世的灰泥丘和托盘海绵礁,而呈现出单个礁体厚度大、发育旋回多之特点,多期礁体的垂向叠加、横向迁移造成礁体叠置连片, 形成了呈条带状展布的大型生物礁群。  相似文献   

Eight new and three recalculated orbits for binaries     

Z. Cvetkovi&#x;  B. Novakovi&#x; 《Astronomische Nachrichten》2010,331(3):304-311

In this paper new orbital elements are given for eleven binaries. For eight of them, WDS 00003–4417 = I 1477, WDS 00106–7313 = I 43 AB, WDS 00366+5609 = A 914, WDS 00519–4343 = I 47, WDS 01315+1521 = BU 506, WDS 01577+4434 = A 1526, WDS 08144–4550 = FIN 113 AB and WDS 08291–4756 = FIN 315 Aa‐Ab, the orbital elements are calculated for the first time. For three of them, WDS 04422+2257 = MCA 16 Aa‐Ab, WDS 08275–5501 = FIN 116 and WDS 14567–6247 = FIN 372, the orbital elements are recalculated. One of the eleven binaries, MCA 16 Aa‐Ab, was discovered by McAlister in 1980 by speckle interferometry and four pairs were discovered by Finsen between 1929 and 1960. For these five pairs, all measured separations are less than 0″.4 and most of the observations were done by using the interferometric techniques. The orbital periods calculated here are between 39 and 270 years. The remaining six pairs were discovered between 1878 and 1926 and most of the observations are visual. They have longer orbital periods, between 384 and 1637 years. In addition to the orbital elements the masses, dynamical parallaxes, absolute magnitudes and ephemerides for the next five years are also given in this paper (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

赛什塘矿区侵入岩的地球化学特征及构造环境分析   总被引：3，自引：0，他引：3  

赖健清  安江华  王雄军  毛寅  宋泽友  曹勇华  陶斤金  郭志军  王晶 《矿产与地质》2010,24(5):460-465

青海赛什塘地区岩体分布普遍,是多期次侵入的结果。岩体主要以高钾、过铝质、同属钙碱性系列为特征,具有较低含量的稀土元素丰度值,轻稀土富集,重稀土亏损,铕异常不明显,属I型花岗岩。岩体有Y/Tb值高低不同的两个源区,一是由柴达木地块东南缘岩石圈地幔构成的地幔楔形体,另一个是受其它物源污染的岩浆,是岛弧形成过程中不同阶段的产物。矿区内发现埃达克岩,岩体富含成矿元素,为成矿提供了物质条件。  相似文献   

Nonlinear spinor field in Bianchi type-I Universe filled with viscous fluid: numerical solutions     

Bijan Saha 《Astrophysics and Space Science》2007,312(1-2):3-11

We consider a system of nonlinear spinor and a Bianchi type I gravitational fields in presence of viscous fluid. The nonlinear term in the spinor field Lagrangian is chosen to be λ F, with λ being a self-coupling constant and F being a function of the invariants I an J constructed from bilinear spinor forms S and P. Self-consistent solutions to the spinor and BI gravitational field equations are obtained in terms of τ, where τ is the volume scale of BI universe. System of equations for τ and ε, where ε is the energy of the viscous fluid, is deduced. This system is solved numerically for some special cases.   相似文献   

山东惠民凹陷东营组尾花介科化石的发现及其意义          下载免费PDF全文

费安玮 《地质论评》2001,47(6):596-601

在山东惠民凹陷渐新统东营组二段发现了浪花介超科尾花介科Recticytherura ualisicosta gen.et sp.nov.－－U形脊直尾花介（新属、新种），化石产于该段近底部含生物砂质灰岩中。这是本区乃至渤海湾盆地下第三系尾花介科化石的首次发现。对该新属、新种进行了描述并据铰合构造、尾突、放射毛细管及壳壁构造等特征判断其为海相介形类。与之共生的介形类的组合特征、壳壁的元素组成特征及围岩的碳、氧同位素特征反映了微咸－半咸水的沉积环境，并由古湖泊的扩张和古气候分析认为东营组二段沉积期在惠民凹陷发生了一次短暂海泛。  相似文献   

AT88SC 1608IC卡与读写器     

饶运涛  朱兆优  邹继军 《华东地质学院学报》2001,24(3):228-232

介绍了AT88SC1608IC卡的特征和利用AT2051单片机设计的IC卡读写器的基本原理及编程。该卡片的存储和保密功能强，读写器的成本低，应用广泛。  相似文献