Using stable isotopes to determine the water sources in alpine ecosystems on the east Qinghai‐Tibet plateau,China     

Wenguang Zhang  Bin Cheng  Zhibin Hu  Shuqing An  Zhen Xu  Yongjun Zhao  Jun Cui  Qing Xu 《水文研究》2010,24(22):3270-3280

To investigate the water circulation of eastern Qinghai‐Tibet plateau during rainy season, water samples of precipitation, throughfall, fog, soil, litter and xylem were collected for stable isotope analysis. The results showed that precipitation mainly originated as a result of the East Asian Monsoon, and the secondarily evaporated water from subalpine ecosystem was an important part in local atmospheric water cycle. The deuterium excess of rainfall in the alpine meadow was evidently higher than the precipitation in the Dengsheng stations. This suggests that a large part of precipitation in alpine meadow was derived from secondarily evaporated water and the mean contribution was 39·57%, about 3·65 mm produced shortly after rain events. Through the contrast of delta (d)‐excess value in different water samples, it could be concluded that the water in subalpine shrubland and transpiration of subalpine dark coniferous forest were the main source of secondarily evaporated water that transferred to alpine meadow. Hence, the precipitation on the east Qinghai‐Tibet plateau was doubly controlled by monsoon and local water circulation in alpine ecosystems. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

太阳活动对GPS卫星广播星历的影响     

宿勇军 《测绘信息与工程》2009,34(6):3-4

采用了切比雪夫拟合多项式内插IGS精密星历,计算了GPS卫星广播星历轨道误差,比较了其在太阳活动谷值和峰值时的误差,讨论了其与太阳活动状况的关系。  相似文献   

Experimental research on fatigue property of steel rubber vibration isolator for offshore jacket platform in cold environment     

Yongjun Xu  Yubiao Liu  Changzhen Kan  Zhonghan Shen  Zhongmin Shi 《Ocean Engineering》2009,36(8):588-594

Jacket platform is the most widely used offshore platform. Steel rubber vibration isolator and damping isolation system are often used to reduce or isolate the ice-induced and seismic-induced vibrations. The previous experimental and theoretical studies concern mostly with dynamic properties, vibration isolation schemes and vibration-reduction effectiveness analysis. In this paper, the experiments on steel rubber vibration isolator were carried out to investigate the compressive properties and fatigue properties in different low temperature conditions. The results may provide some guidelines for design of steel rubber vibration isolator for offshore platform in a cold environment, and for maintenance and replacement of steel rubber vibration isolator, and also for fatigue life assessment of the steel rubber vibration isolator.  相似文献   

AVO理论公式表达形式的差异性和统一性     

潘海滨  何拥军  张勇 《海洋地质与第四纪地质》2009,(3)

Knott(诺特)方程是AVO理论公式的位移位表达形式。同一个弹性界面的边值定解问题在数学上的不同表述方式将导致Knott方程出现多种表达形式。研究表明,XOZ平面内,P和SV平面简谐波入射到弹性界面时遵循的Knott方程共有8种独立表达形式,其中纵波和横波各有4种;对于相同类型的平面简谐波入射和相同的入射介质,不同形式的Knott方程可以完全统一于相同表达形式的能量平衡方程。  相似文献   

LA-ICP-MS Zircon U-Pb Age of Newly Discovered Hatu Tectonic Mélange in the West Junggar, Xinjiang, NW China     

DUAN Fenghao  LI Yongjun  ZHI Qian  YANG Gaoxue  LUO Xin  LI Yuhang 《《地质学报》英文版》2020,94(4):1317-1318

正Objective The West Junggar, situated in the southwestern segment of the Central Asian Orogenic Belt, is considered to be an important area for Phanerozoic crustal growth owing to the excellent exposures of diverse rock types and multiple generations of structures and magmatic rocks. Recently, a new tectonic mélange has been identified in the southern West Junggar during geological mapping at a scale of 50000. This work presents new geochronological data for  相似文献   

河北峪耳崖金矿矿床成因及成矿模式   总被引：1，自引：0，他引：1       下载免费PDF全文

赵海玲  杨秋立 《地球科学》1997,22(3):275-278

峪耳崖金矿是冀东地区一个典型的热液型矿床、硫、铅同位素组成表明太古宙变质岩是本区金矿的主要矿源层，是壳幔相互作用的结果，氧同位素表明水的来源以大气降不为主，在大气降水深循环过程中，金从围岩中多次萃取，频敏的岩交活动使成矿元素进一步富集，成矿流体的组成、盐度、ＰＨ，Ｅｈ，ｆ（Ｏ２）表明金是以「Ａｕ（ＨＳ）２」络离子形式迁移，由于物理化学条件的改变，导致了金的沉淀，在ＮＥ和ＮＮＥ向构造裂隙发育部位形成  相似文献   

冀中早第三纪湖盆演化、油气评价与找油方向   总被引：38，自引：6，他引：38       下载免费PDF全文

张文朝  崔周旗  韩春元  郭永军  王洪生  李莉  王海潮  李新坡 《古地理学报》2001,3(1):45-54

根据冀中坳陷大量钻井岩性剖面、地震测线和实验室分析等资料，运用沉积学、层序地层学和石油地质学等多学科理论为指导，深入研究冀中坳陷下第三系区域地质特征、层序地层特征、沉积环境变迁、沉积相带展布和油气分布状况。把冀中坳陷下第三系划分为断陷分割充填期、断陷扩张深陷期、断陷萎缩期、断坳扩展期和断坳抬升消亡期五个演化阶段。最终把区内12个凹陷划分为继承型、早盛型、过渡型、偏移型和沉降型五种类型湖盆，并对它们进行了含油气评价；指出廊固和坝县凹陷具有良好的油气勘探前景，是今后油气勘探的主攻方向；饶阳凹陷东部、晋县和束鹿凹陷，要立足小断块，不断发现小油藏，保证冀中油气长期稳产。  相似文献   

Accumulation and Cycle of Heavy Metals in Sonneratia apetala and S. caseolaris Mangrove Community at Futian of Shenzhen, China     

王伯荪  昝启杰  张炜银  王勇军 《海洋通报(英文版)》2003,5(1)

Wetland ecosystem in the Shenzhen Bay is one of the internationally important ecosystems in South China Region. Its core, with the Mai Po Mangrove Nature Reserve in Hong Kong on the one side and the Futian Mangrove Nature Reserve in Shenzhen on the other side, provides habitats for many rare and endangered wild birds, especially for migratory birds[1, 2]. With the economic development in Hong Kong and Shenzhen, a large mount of silt and untreated waste water are poured into the Shenzhe…  相似文献   

我国近海油气资源基本状况及勘探方向探讨     

何拥军 《中国海洋大学学报(自然科学版)》2003,33(6):930-936

本文通过对我国近海油气资源的分布特征进行分析 ,指出渤海湾盆地是我国近海石油的主力产区。天然气的主力产区为莺歌海盆地和东海陆架盆地 ,目前勘探的重点应放在渤海湾盆地 ,其次是东海陆架盆地 ,珠江口盆地第三。在加强对新生代盆地勘探的同时 ,应重视对中生代地层的勘探 ;在深化浅水区勘探的同时 ,不失时机地开展深水勘探 ;在加强构造圈闭勘探的同时 ,密切注视非构造圈闭的油气资源的勘探  相似文献   

STABILITY ANALYSIS OF RIVERBANK SUBJECT TO SEEPAGE     

Yan LU Yongjun LU Xingnong ZHANG 《国际泥沙研究》2007,22(4):282-291

The stability of riverbanks subject to seepage is studied experimentally and theoretically in this paper. By including seepage in a 3-dimensional theoretical analysis, the study first shows how the critical slope or angle of repose of a cohesionless material is related to the ratio of the hydraulic gradient of seepage to its critical value under the fluidization condition. The critical stable slope is shown to be related to not only the hydraulic gradient but also the seepage direction. Measured laboratory data reasonably fit well with the theoretical relationship for the case of injection and suction. The data reveal that the slope is reduced with injection and increased with suction, respectively. Additionally, the study identifies the seepage direction which results in a minimum critical stable slope for a certain hydraulic gradient of seepage.  相似文献