^226Ra and ^228Ra in the Seawater of the Western Yellow Sea     

MEN Wu )  WEI Hao )  and LIU Guangshan )  * ) College of Oceanography  Environmental Science  Xiamen University  State Key Laboratory of Marine Environmental Science 《中国海洋大学学报(英文版)》2006,5(3):228-234

1Introduction Therearefourradiumisotopesinnature,ofwhich224Ra,226Raand228Rahavebeenwidelyinvestigated inmarineresearch,butthespecificactivityof223Rais toolowtobemeasured,therefore,itsapplicationsarelimited(Moore,1969;Broeckeretal.,1976;KuandLin,1976;Nozak…  相似文献   

一种新型测向传感器——磁通门罗盘     

胡平  孟宪萍  江钩仁 《海洋与湖沼》1992,23(3):318-324

本文对磁通门罗盘的基本工作原理、实验线路以及主要技术指标和一些测量数据作简要介绍,最后对仪器的误差进行简单分析并提出一些减小误差的改进措施。  相似文献   

南海中部和冲绳海槽沉积物中的氨基酸物质   总被引：2，自引：0，他引：2  

郑士龙  唐运千 《海洋学研究》1993,11(2):34-42

本文通过对南海中部和冲绳海槽三个深海沉积物柱状样腐植物质水解氨基酸的研究,试图阐述南海和冲绳海槽沉积物的演化与沉积环境。  相似文献   

黄海多毛类裂虫科小型种的初步研究     

孟凡  丁志虎  赵晶  吴宝铃 《海洋科学进展》1993,(1)

1987～1991年在黄海进行小型多毛类调查时,采到的裂虫科小型种标本,经鉴定有18种,其中9种在我国是首次记录。  相似文献   

几种地质图件的数据存贮与处理          下载免费PDF全文

门桂珍  萨贤春  雷宝林 《沉积与特提斯地质》1995,(2):40-45

本文主要叙述了在开发煤矿地质信息系统(CMGIS)中的几种主要地质图件的数据存贮与处理技术。地质图件作为一种专业图件,有它特有的属性,如岩性花纹符号的大量出现,各种构造、地物等特殊线条的出现,地质曲线与文字标注的大量出现等。实践表明,采用商品化通用软件包(Auto CAD)已满足不了用户的要求,因为它缺乏地质上所需要的特殊性线型。用它编辑后的图形数据难以二次利用,图素的地质含义不再表现在图形数据库中,况且,如果图形编辑量过大,还必须考虑是否要对原始数据进行调整或增加辅助数据,为此,用户必须在不同的软件环境下运行不同的软件和数据,造成用户学习掌握和使用上的困难。  相似文献   

辽南复州湾太原组的燕海扇类     

门凤岐  李亚美  尹秀英 《吉林大学学报(地球科学版)》1990,(4)

本文记述了发现于辽南复州湾上石炭统太原组的燕海扇类,计5属17种。讨论了Annuliconcha与Paradoxipecten的属征及有关问题。上述发现在东北地区尚属首次。  相似文献   

吉林台爆破料应力应变关系的三轴试验研究     

侯新强  张远芳  高盟  慈军  刘红  张之科 《新疆地质》2005,23(2):194-198

通过室内大型三轴实验，研究了吉林台水库爆破料在不同级配下的应力应变关系，得到了在一定击实功下爆破料的最大干密度随细料含量变化的规律，分析了爆破料在不同级配和不同围压下应力与应变的变化规律、轴向应变与体积应变的关系及抗剪强度变化特性．从微观的角度说明了变化规律产生的原因，得出爆破料的抗剪强度随级配的变化而变化的规律．  相似文献   

Mean flow-transient perturbation interaction in the Southern Hemisphere: a simulation using a variable-resolution GCM     

A. Carril  C. Menéndez  M. Nuñez  H. Le Treut 《Climate Dynamics》2002,18(8):661-673

The ability of an atmospheric general circulation model to reproduce fundamental features of the wintertime extratropical Southern Hemisphere (SH) circulation is evaluated with emphasis on the daily variability of the SH mean flow and the mean flow-transient perturbations interaction. Two 10-year simulations using a new version of the LMDZ GCM with a stretched grid scheme centered at 45 °S and forced by climatological SST are performed: a high (144Ꮡ) and low (64Ꭹ) horizontal resolution runs. The performance of both simulations was determined by comparing several simulated fields (zonal wind, temperature, kinetic energy, transient eddy momentum and heat fluxes, Eliassen-Palm fluxes, Eady growth rate and baroclinic conversion term) against the European Centre for Medium Range Weather Forecast reanalyses (ERA). High and low-resolution simulations are similar in many respects; in particular, both experiments reproduce the main patterns of the southern extratropical large-scale circulation satisfactorily. Increasing resolution does not improve universally some spurious aspects of the low resolution simulation (e.g. the cold bias in the high polar troposphere, the debilitated subtropical jet, the low baroclinic conversion rate). Those aspects present little sensitivity to the model resolution. The interaction between transient eddies and zonal mean flow are examined. The low-resolution experiment is able to qualitatively represent the acceleration/deceleration of the mean flow by transient perturbations, south/north of 30 °S with an accuracy similar to that of the high-resolution experiment. Although both experiments represent the baroclinic structure of the mean flow satisfactorily, the model underestimates some transient properties due to the underestimation of the baroclinic conversion term in middle latitudes. Such misrepresentation does not improve with increasing resolution and is related to the relatively weak meridional temperature gradient and the inadequate geographical distribution of the eddy heat fluxes. In particular, the eddy kinetic energy is always underestimated. Eddy kinetic energy does not improve convincingly with increasing resolution, suggesting that the adequate representation of the storm tracks is highly influenced by the physical parametrizations.  相似文献   

Predictive GIS-Based Model of Rockfall Activity in Mountain Cliffs   总被引：6，自引：1，他引：6  

Marquínez  J.  Menéndez Duarte  R.  Farias  P.  JiméNez Sánchez  M. 《Natural Hazards》2003,30(3):341-360

Rockfall susceptibility has been analysed in mountain cliffs of the Cantabrian Range, North Spain. The main aim of this analysis has been to build a predictive model of rockfall activity from a low number of environmental and geological variables. The rockfall activity has been quantified in a GIS. The cartographic information used shows the spatial distribution of all the recent talus screes as well as their associated source areas in the rock-slopes. The area relation At/Ar (recent talus scree polygon/source basins) in the rock slopes has been used as the rockfall activity indicator. This relation has been validated in 50 pilot rock-slopes and compared with the relation number of recent rock fragments/source basin, obtained from field work. The environmental factors causing rockfall depend on the rock slope situation, and these are: altitude and sun radiation on the rock cliff. The geological factors considered are: lithology, relative position of the main discontinuities with respect to the topographic surface and two morphologic parameters: the roughness and slope gradient. A logistic regression analysis has been applied to a population of 442 limestone and quartzite rock cliffs. The dependent variable is the rockfall activity indicator, which allows the definition of two classes of rock cliff units: low and high activity. The independent variables are altitude, sun radiation (equinox radiation, summer solstice radiation, winter solstice radiation), slope roughness, slope gradient,anisotropy and lithology. Results suggest that it is possible tobuild a valid cartographic predictive model for rockfall activity in mountain rock cliffs from a limited number of easily obtainable variables. The method is especially applicable in massive rock slopes or in regions with uniform rock mass characteristics.  相似文献   

Changes in potential evapotranspiration and surface runoff in 1981–2010 and the driving factors in Upper Heihe River Basin in Northwest China          下载免费PDF全文

Kaisheng Luo  Fulu Tao  Xiangzheng Deng  Juana P. Moiwo 《水文研究》2017,31(1):90-103

Changes in potential evapotranspiration and surface runoff can have profound implications for hydrological processes in arid and semiarid regions. In this study, we investigated the response of hydrological processes to climate change in Upper Heihe River Basin in Northwest China for the period from 1981 to 2010. We used agronomic, climatic and hydrological data to drive the Soil and Water Assessment Tool model for changes in potential evapotranspiration (ET₀) and surface runoff and the driving factors in the study area. The results showed that increasing autumn temperature increased snow melt, resulting in increased surface runoff, especially in September and October. The spatial distribution of annual runoff was different from that of seasonal runoff, with the highest runoff in Yeniugou River, followed by Babaohe River and then the tributaries in the northern of the basin. There was no evaporation paradox at annual and seasonal time scales, and annual ET₀ was driven mainly by wind speed. ET₀ was driven by relative humidity in spring, sunshine hour duration in autumn and both sunshine hour duration and relative humility in summer. Surface runoff was controlled by temperature in spring and winter and by precipitation in summer (flood season). Although surface runoff increased in autumn with increasing temperature, it depended on rainfall in September and on temperature in October and November. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献