The 1997 hard-state outburst of the X-ray transient GS 1354−64/BW Cir     

C. Brocksopp  P. G. Jonker  R. P. Fender  P. J. Groot  M. van der Klis  S. J. Tingay 《Monthly notices of the Royal Astronomical Society》2001,323(2):517-528

We present observations of the 1997 outburst of the X-ray transient GS 1354−64 (BW Cir) at X-ray, optical and, for the first time, radio wavelengths; our results include upper limits to the linear and circular polarization for the radio data. The X-ray outburst was unusual in that the source remained in the low/hard X-ray state throughout; the X-ray peak was also preceded by at least one optical outburst, suggesting that it was an 'outside-in' outburst – similar to those observed in dwarf novae systems, although possibly taking place on a viscous time-scale in this case. It therefore indicates that the optical emission was not dominated by the reprocessing of X-rays, but that instead we see the instability directly. While the radio source was too faint to detect any extended structure, spectral analysis of the radio data and a comparison with other similar systems suggest that mass ejections, probably in the form of a jet, took place and that the emitted synchrotron spectrum may have extended as far as infrared wavelengths. Finally, we compare this 1997 outburst of GS 1354−64 with possible previous outbursts and also with other hard-state objects, both transient and persistent. It appears that a set of characteristics – such as a weak, flat-spectrum radio jet, a mHz QPO increasing in frequency, a surprisingly high optical/X-ray luminosity ratio, and the observed optical peak preceding the X-ray peak – may be common to all hard-state X-ray transients.  相似文献   

南北半球高低层环流切变与长江流域夏季降水异常的关系   总被引：2，自引：2，他引：2       下载免费PDF全文

艾 《应用气象学报》2005,16(Z1):48-55

利用奇异值分解 (SVD)方法分析和讨论了夏季 85 0hPa和 2 0 0hPa高低层纬向风距平差与我国夏季降水异常的关系 ,发现澳大利亚东北部高低层纬向风切变与长江中下游地区降水有较好的反相关 ,并定义了澳大利亚季风指数。 9个澳大利亚冬季风 (南半球 )指数低值年与 7个高值年我国夏季降水的平均差值图表明 ,显著的降水差异出现在长江中下游 ,低值年有利于长江中下游地区降水偏多 ;澳大利亚冬季风指数与夏季北半球 5 0 0hPa高度场的相关图在东亚至西太平洋的相关分布呈现出“ - -”结构 ,在我国长江以南的中低纬和贝加尔湖的高纬地区是负相关区 ,正相关在我国北方至日本的中纬地区。  相似文献   

Trimble随机软件基线格式转换方法与实现     

廖超明  谭庆林  钟承志 《测绘信息与工程》2006,31(5):24-25

分析了Trimble随机软件新、旧基线数据格式,讨论了GPS基线格式转换的实现方法,编写了专用接口程序,实现了新、旧GPS基线格式的自动转换。  相似文献   

南阳凹陷致密储层钻井液损害评价及酸化改造对策研究     

向阳  向丹 《矿物岩石》2001,21(4):71-74

本文通过矿物使用的钻井液和酸化解堵液对储层岩石所作的损害评价试验证实，该区储层产能低的原因之一是钻井液和酸化解堵液使储层渗透率损害达35％－75％造成。针对该区储层实际，采用作者研制的酸液解堵模拟试验证实，可使储层渗透率恢复到原始值的89％－185％，平均恢复至原始值的110％，适用于该区储层的酸化解堵。  相似文献   

东北夏季气温的大尺度环流影响因子分析     

李宗昊  房一禾  徐方姝  席晓彤  王修莹  周晓宇  徐红  蔡冰  马凡舒 《气象科技》2016,44(6):965-971

利用1961—2010年东北地区3省53站月平均气温资料及分辨率为2.5°×2.5°的NCEP/NCAR再分析资料,采用统计分析方法,分析了东北夏季气温的大尺度环流影响因子。利用200hPa风场要素定义了一个适于描述东北夏季气温的200hPa纬向风切变指数,并给出了该指数的预测方法,以期为东北夏季气温的预测提供一个诊断工具。结果表明:鄂霍次克海和北太平洋中部海平面气压场偶极子,与东北夏季气温关系密切;同期东北地区上空500hPa位势高度场与东北夏季气温呈正相关关系;同期850hPa、200hPa矢量风场和整层水汽通量场在东北及其以西地区上空呈气旋式环流,对应东北夏季气温偏低,反之则偏高,同时来自孟加拉湾的水汽也是造成东北夏季气温异常的因素之一;200hPa纬向风切变指数与东北全区气温呈显著正相关,该指数偏大对应东北夏季气温偏高,反之东北夏季气温偏低。4月和5月热带印度洋和太平洋海温与夏季200hPa纬向风切变指数关系密切。  相似文献   

9012号热带气旋登陆后维持不消的动力机制     

梁力  吴志伟  严光华 《热带气象学报》1995,11(1):26-34

分析了影响南海的几类台风路径所对的２００ｈＰａ辐散风场和速度热场的特征,发现２００ｈＰａ辐散风场对台风路径有一定的制约作用。主要体现在：（１）２００ｈＰａ辐散风场表征的季风环流结构的差异决定着台风路径扣期趋势;（２）西太平洋副高所对应的辐散风次级辐台线的走向和西伸程度指示着信风特征,影响台风未来的路径;（３）台风一般向辐散中心以外的次级辐散线西侧２个经距的位置移动,用辐散风环流的物理意义和台风受环  相似文献   

天宝GNSS原始观测数据批量转换RINEX格式的方法研究     

赵忠海  袁宜 《测绘与空间地理信息》2017,40(5)

简要介绍了天宝GNSS原始观测数据和RINEX格式数据的特点,对目前可用的天宝GNSS原始数据转换为RINEX格式的软件进行了详细的说明,并利用Python语言实现了批量转换,满足了测绘、国土等行业对于大量天宝观测数据转换的需求。  相似文献   

Climate and environment during the Younger Dryas (GS‐1) as reflected by composite stable isotope records of lacustrine carbonates at Torreberga,southern Sweden     

Dan Hammarlund  Thomas W. D. Edwards  Svante Bjrck  Bjrn Buchardt  Barbara Wohlfarth 《第四纪科学杂志》1999,14(1):17-28

Climatic and environmental changes during the Younger Dryas stadial (GS‐1) and preceding and following transitions are inferred from stable carbon and oxygen isotope records obtained from the sediments of ancient Lake Torreberga, southern Sweden. Event GS‐1 is represented in the sediment sequence by 3.5 m of clay containing lacustrine carbonates of various origins. Comparison of isotopic records obtained on mollusc shells, ostracod valves, and Chara encrustations precipitated during specific seasons of the year supports estimates of relative changes in both lake water and mean annual air temperatures. Variations in soil erosion rates can also be estimated from a simple isotope–mass‐balance model to separate allochthonous and autochthonous carbonate contributions to the bulk carbonate content of the sediments. The well‐known, rapid climatic shifts characterising the Last Termination in the North Atlantic region are clearly reflected in the isotopic data, as well as longer‐term changes within GS‐1. Following maximum cooling shortly after the Allerød–Younger Dryas (GI‐1–GS‐1) transition, a progressive warming and a slight increase in aquatic productivity is indicated. At the Younger Dryas–Preboreal (GS‐1–PB) transition mean annual air temperature rapidly increased by more than 5°C and summer lake‐water temperature increased by ca. 12°C. The subsequent Preboreal oscillation is characterised by an increase in soil erosion and a slight decrease in mean annual air temperature. These results are in harmony with recent findings about large‐scale climate dynamics during the Last Termination. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

飞马F200无人机在大型水利工程及BIM建设中的应用   总被引：1，自引：0，他引：1  

贾智乐 《测绘通报》2019,(9):159-162

随着无人机技术的飞速发展,传统测量的单一化成果已经不能满足水利工程设计规划的需求。本文基于飞马F200无人机航测系统在大型拟建水库——信阳袁湾水库中的应用,探索并验证了一种高精度航测成图的方法。并在此基础上,融合基于BIM技术的单体化模型,实现了大型水利工程项目在可研阶段基于三维场景的应用和分析研究,为智慧水利的构建提供了数据支撑。  相似文献   

基于Trimble GNSS系统的电力工程测绘内外业一体化作业     

李斌  马超  常增亮  高兴国  曲萌 《测绘通报》2020,(12):164-166

由于电力工程测绘的特殊性,传统电力工程测绘生产模式内外业分离,导致重复劳动且工作效率低下。针对此问题,本文基于Trimble GNSS系统提出了一种新的解决方案,开发出一套内外业一体化作业系统,解决了不同设备端数据通信、地物属性编码统一、底图加载与草图绘制等技术难题,能够实现外业轻松采集测量数据和地物属性,并自动生成CASS、道亨野外操作码文件及生成相关报表。经实地工程测试,该系统不仅节约大量的时间和人力物力,而且直观易用,不易出错。  相似文献