摄影全站系统及其精度评定     

靳志光  卫建东  汤廷松  余春平  蒲亭汀 《海洋测绘》2008,28(4):76-78

摄影全站系统是成熟的数字摄影测量技术与高精度工程测量仪器（全站仪）的集成，可以实现无接触和无控制测量，对摄影测量的发展具有重要的作用。以GFF-7000I摄影全站系统为研究对象，分别对其简单测量模式和标准测量模式进行了不同距离上的精度测试，对摄影全站系统的应用具有一定的指导意义。  相似文献   

Range-wide population structure and history of the northern quahog (Merceneria merceneria) inferred from mitochondrial DNA sequence data     

Baker  Patrick; Austin  James D.; Bowen  Brian W.; Baker  Shirley M. 《ICES Journal of Marine Science》2008,65(2):155-163

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中国癌症与土壤环境中碘元素的关系     

曾昭华  曾雪萍 《南方国土资源》2000,13(1):41-44

利用土壤环境中碘元素资料769个数据,癌症死亡调查资料787 080例,研究了胃癌、食管癌、肝癌、宫颈癌、肺癌、大肠癌、白血病、鼻咽癌、乳腺癌死亡率与人群生存区土壤环境中碘元素的关系.结果表明,胃癌、食管癌、肝癌、宫颈癌、鼻咽癌死亡率与碘元素有相关性.  相似文献   

Phylogeography of Ophryotrocha labronica (Polychaeta,Dorvilleidae) along the Italian coasts          下载免费PDF全文

Piero Cossu  Ferruccio Maltagliati  Federica G. Pannacciulli  Roberto Simonini  Gloria Massamba‐N'Siala  Marco Casu  Claudio Lardicci  Daniela Prevedelli  Alberto Castelli 《Marine Ecology》2015,36(4):1088-1097

Species of the genus Ophryotrocha are a well‐studied group of organisms but, despite the relatively large body of biological studies, little is known about their intra‐specific patterns of genetic diversity. In the present study, we analysed the patterns of genetic variation in samples of Ophryotrocha labronica (Polychaeta, Dorvilleidae) collected along the Italian coasts within three regions with different thermal regimes: the Northern Adriatic Sea (NAS), the Ligurian Sea (LS), and the South/Southeast Sicilian Sea (SS). A partial sequence of the cytochrome c oxidase subunit I (COI) gene was used as a genetic marker. An analysis of molecular variance (AMOVA) showed significant genetic differentiation between the NAS and the other regions. Conversely, little or no genetic structuring was found between the LS and the SS or amongst locations within a given region. A Bayesian phylogenetic tree and a median‐joining network provided evidence for the occurrence of two highly divergent genetic lineages characterized by a high average sequence divergence (17.2%, Kimura two‐parameter distance). The spatial patterns of genetic variation found in O. labronica may reflect the signature of past expansion events of the two genetic lineages. Although the high sequence divergence suggested that cryptic speciation within O. labronica may have occurred, other traits such as the absence of reproductive isolation, pattern of phenotypic variation and habitat specificity prompted us to regard the two groups as distinct COI lineages of O. labronica.  相似文献   

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