Taxonomic reexamination of the genus Chirolophis in China waters     

Liu Jing  Tian Mingcheng  You Feng 《中国海洋湖沼学报》2005,23(2):199-203

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Direct comparison of UK temperatures and Greenland snow accumulation rates, 15000—12000 yr ago     

J. J. Lowe  G. R. Coope  C. Sheldrick  D. D. Harkness  M. J. C. Walker 《第四纪科学杂志》1995,10(2):175-180

A palaeotemperature record based on fossil coleopteran evidence and dated by accelerator mass spectroscopy (AMS) ¹⁴C determinations on plant macrofossils has been obtained for the last glacial-interglacial transition from the site of Gransmoor in eastern England. Calibration of the radiocarbon measurements enabled a direct comparison to be made between this palaeotemperature curve and the snow accumulation record from the GISP-2 Greenland ice-core. The similarity between the two data sets suggests a degree of correspondence in the pattern and timing of climatic change in Greenland and the British Isles at the end of the last cold stage.  相似文献   

西安灞河左库滑坡发育的阶段性及形成主因的历史转化     

赵法锁  毛彦龙 《地球科学与环境学报》1995,(3)

根据西安灞河左岸滑坡的基本特点、空间展布规律以及与后期沉积物之间的接触关系，本文分析论证了该区滑坡发育的阶段性特征及各阶段滑坡形成的主要原因与营力因素的历史转化性问题。  相似文献   

The impact of the October–November 2000 floods on contaminant metal dispersal in the River Swale catchment,North Yorkshire,UK     

Ian A. Dennis  Mark G. Macklin  Tom J. Coulthard  Paul A. Brewer 《水文研究》2003,17(8):1641-1657

During the autumn of 2000, large areas of England and Wales were affected by severe flooding, which caused widespread disruption and significant damage to property. This study attempts to determine the impact of these flood events on contaminated sediment dispersal and deposition in the River Swale catchment, Yorkshire, UK, where lead and zinc were extracted and processed in large quantities during the nineteenth century. Seventy samples of overbank and channel‐edge sediments were collected at 35 sites along the River Swale. Inductively coupled plasma‐mass spectrometry was used to measure contaminant metal concentrations in the 2000–63 µm (sand) and <63 µm (silt and clay) size fractions. In both the channel‐edge and overbank sediments collected from the upper and middle reaches of the River Swale, concentrations of lead, zinc and cadmium were found to exceed MAFF guidelines. Highest concentrations correspond to the input of contaminated material from intensively mined tributaries, and elevated levels can be observed 5–10 km downstream of these inputs. This indicates that the remobilization of contaminated material during major flood events is potentially a serious problem for activities such as agriculture that utilize the Swale floodplain. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

天再旦日食的根据与计算——对Keenan质疑的注释     

刘次沅 《时间频率学报》2002,25(1):70-73,80

作者由“天再旦”日食说证实西周懿王元年为公元前 899年。夏商周断代工程以此为支点之一 ,得到西周年代表。针对读者的质疑 ,在历史文献的可靠性、天光视亮度的表达和计算方法、地球自转长期参数等方面做了进一步的阐述。  相似文献   

基于C#语言的国(境)外地震背景信息交互式产出系统     

马秀丹  陈姝荞  龙海云  张晋辉 《地震地磁观测与研究》2021,42(1):162-168

针对国(境)外地震专报产出过程中遇到的信息搜索困难、内容不规范、难以满足时效性等问题,基于C#编程语言,设计开发了国(境)外地震专报背景信息交互式产出系统。该系统只需值班人员少许的参与,自动获取人口信息、海啸信息、震中附近一定范围内的历史地震目录,生成地震的人口伤亡信息,最终产出word格式的地震专报。  相似文献   

2021年5月22日玛多M_S 7.4地震地震动特征     

万秀红  吴哲  李智敏  屠泓为  李鑫 《地震地磁观测与研究》2021,42(5):42-50

为了研究2021年5月22日玛多M_S 7.4地震地震动特征,收集16个强震台的峰值加速度和其中9个台的强震波形数据,利用峰值加速度衰减及反应谱等分析玛多M_S 7.4地震强震动特征。结果表明,多数台站的PGA值都随震中距的增大而平稳下降,PGA的衰减特征与青藏区衰减关系间有较好的一致性;土层台与基岩台的加速度反应谱明显不同,震中距越小,短周期高频成分越多,衰减越快,震中距越大,长周期高频成分越少,衰减越慢;加速度反应谱的水平向与竖向比值曲线在4 s内呈现两峰一谷的现象,初步认为,距发震断层较近的野马滩1号大桥所受到的破坏及水泥路面的明显错断受水平向地震动作用的影响更大。  相似文献   

地震长期效应对黄土力学性质的影响          下载免费PDF全文

刘伟  谌文武  杨芳 《地震工程学报》2021,43(4):965-976

黄土高原地区,具有大孔隙、弱胶结特征的黄土遭遇地震荷载影响后,其内部结构受到扰动,微结构的变化会在后期物理力学性质中集中反映出来。通过动三轴试验对原状黄土试样进行模拟历史地震预处理,对处理试样依次进行饱和、固结、不排水剪切试验。结果表明:黄土试样的初始含水率为10%时,经历历史地震扰动的黄土较未扰动黄土相比,其偏应力明显增加,孔隙水压力降低,抗剪强度指标值增大3.42 kPa和2.67°;当初始含水率增加至15%时,历史地震产生的长期效应将引起后期黄土强度持续增大,增幅远远超过10%的黄土试样,黏聚力和内摩擦角达到3.98 kPa和3.02°。通过扫描电镜试验和压汞试验,从微观角度分析地震长期效应对黄土力学性质影响的内在机制,结果发现历史地震引起黄土内部颗粒移动、孔隙结构变化是黄土强度增加的重要因素。  相似文献   

Holocene-historical volcanism and active faults as natural risk factors for Armenia and adjacent countries     

A. Karakhanian  R. Djrbashian  V. Trifonov  H. Philip  S. Arakelian  A. Avagian 《Journal of Volcanology and Geothermal Research》2002,113(1-2)

Examples of Holocene-historical volcanism in the territory of Armenia and adjacent areas of Eastern Anatolia and Western Iran are discussed. Holocene-historical activity is proved for the volcanoes of Tskhouk–Karckar, Porak, Vaiyots-Sar, Smbatassar and Ararat. Based on the analysis of remote sensing data, field work, and historical and archeological information, it is demonstrated that there was a considerable number of cases of volcanic activity in Armenia and adjacent regions of Turkey, Syria and Iran during the historical period. The Holocene volcanic centers are situated within pull-apart basin structures and controlled by active faults. Situated in an area prone to many types of natural hazards, Armenia and adjacent countries face high natural risk. The evidence presented shows that volcanic hazard also contributes to the natural risk for these countries.  相似文献   

地理空间系统史料库构建的几个问题     

牛岸英 《测绘科学》2011,36(4):100-102

本文结合甘肃等地的区域地理信息数据库构架研究,分析了史料库建设的薄弱环节和主要问题提出以同步建库的技术路线,保持当期历史数据体的完整性;以差别化构建的原则组织历史数据,确保完整入库,防止史料散失.  相似文献