松嫩平原哈尔滨地区地下水环境背景值分析          下载免费PDF全文

李天宇  董宏志  孔庆轩  卞建民 《水文》2016,36(3):24-28

受自然条件及人类活动的影响,地下水环境发生了较大的变化,地下水污染问题日益引起广泛的关注。正确确定背景值对地下水污染评价十分重要。以收集的松嫩平原哈尔滨地区150余组地下水水化学样品分析数据为依据,在分析区域流场、补给径流条件的基础上,选用数理统计法和经验法求取了研究区潜水和承压水地下水环境背景值,并对地下水环境背景值进行比较。结果表明:数理统计法以自然地理环境和人类长期活动的综合作用为基础,克服了经验法的不足,可较真实地反映研究区地下水背景状况;研究区内潜水中指标NO3-、Fe、Mn和承压水中指标Fe、Mn均为高背景值指标;区内地下水环境背景值与人类活动、地下水的补、径、排和沉积环境条件具有密切的关系。  相似文献   

汕尾市区砂土液化分析     

王维亮 《华南地震》2004,24(2):62-68

采用标准贯人试验法对抽取的汕尾市区34个野外钻孔资料进行液化分析,计算液化指数,判断液化等级,进而划分液化小区。结果表明,汕尾市区滨海堆积平原普遍存在砂土液化地震地质灾害,液化等级轻微、中等至严重均有分布,以中等液化为主。根据建筑物类别和工程建设场地的实际情况提出抗液化措施的建议。  相似文献   

Distribution of sediment chloroplastic pigments in the Southern Yellow Sea,China   总被引：3，自引：0，他引：3  

LIU Xiaoshou  ZHANG Zhinan  WU Yiping  HUANG Yong  and ZHANG Yan College of Marine Life Sciences  Ocean University of China  Qingdao  P.R.China Agricultural College  Liaocheng University  Liaocheng  Shandong  P.R.China 《中国海洋大学学报(英文版)》2005,4(2):163-172

The distribution of sediment chloroplastic pigments (Chl-a, i.e. chlorophyll a and Pha-a, i.e. phaeophorbide a) in the Southern Yellow Sea of China was studied. Samples were collected from four cruises in January and June 2003, and January and June 2004. The results show that the vertical distribution of Chl-a and Pha-a in the sediment layers 0-2cm, 2-5cm and 5-8cm, follows a stable ratio, 5:3:2. The average ratio of Pha-a to Chl-a in sediment is 2.83. Spearman 2-tailed rank correlation analysis shows that Chl-a and Pha-a contents in each sediment layer have a highly significant correlation. The average contents of Chl-a and Pha-a in the sediment of the 0-8cm layer in the investigated area are 0.31 -0.47μgg-1 and 1.28-1.40 μgg-1 sediment (dry weight), respectively. The average Chl-a and Pha-a contents in sediment are higher in summer than in winter. ANOVA analysis shows that there is a highly significant variation among the Chl-a contents (P = 0.002 <0.01) of the four cruies, but this is not true for the case of Pha-a content (P = 0.766>0.05). The average Chl-a and Pha-a contents in the 2 sediment layers (0-2cm and 2-5cm) have significant or highly significant correlations with organic matter (OM), median diameter (Mdφ), silt plus clay percentage in the January 2003 cruise. In the June 2003 cruise, the average Chl-a content in the 3 sediment layers (0-2cm, 2-5cm, and 5-8cm) has a significant correlation with meiofauna biomass, and Pha-a content has highly significant correlations with water depth, bottom water temperature, OM and Mdφ The contents of Chl-a and Pha-a are lower than those in estuaries and intertidal areas, but close to those in the same area studied previously.  相似文献   

基于决策树考虑地形特征的场地参数估计方法   总被引：1，自引：0，他引：1  

张雨婷  任叶飞  温瑞智  王大任  冀昆 《地球物理学报》2022,65(2):698-710

发展基于地形特征的场地参数VS30估计方法因其具有重要应用需求而成为研究热点.以我国新疆维吾尔自治区和河北省的DEM数据和工程钻孔资料验证了基于决策树理论考虑地形特征的VS30估计方法在我国的适用性,检验方法的准确性和对DEM数据精度的敏感性.得到如下结论:(1)基于决策树理论考虑地形坡度、表面纹理和局部凸度划分了两个...  相似文献   

Shifts in the Processes of Oxygen and Nutrient Balances in the River Elbe since the Transformation of the Economic Structure     

H. Guhr  B. Karrasch  D. Spott 《洁净——土壤、空气、水》2000,28(3):155-161

The reduction of pollution in the river Elbe since 1990 has resulted in changes in the processes taking place in the river. The heterotrophic degradation which dominated until 1990 was accompanied by a lack of oxygen, floating masses of sewage fungi, and sludge formation in the areas of still water. Since the early 1990s, autotrophic processes have come to dominate, with an increase in pH fluctuations and the oxygen production potential, but evidently not the chlorophyll level during the growing season. The degradable organic pollution of the Elbe is determined by algae production. The high levels of ammonium previously encountered in the Elbe were attributable to not only dischargers but also in particular the lack of oxygen in the water. Via heterotrophic nitrate assimilation, nitrate served as an oxygen reserve, resulting in high levels of nitrite. At present, when the oxygen contents are sufficient, the concentration reductions of nitrate and nitrite along the reach of the Elbe are approximately parallel, which in view of the lack of ammonium indicates the denitrification of microzones low in oxygen. The relative proportion of structurally bound substance turnover will become increasingly important for the Elbeπs material budget.  相似文献   

南海西北部夏季叶绿素a浓度的分布特征及其对海洋环境的响应   总被引：8，自引：0，他引：8  

赵辉  唐丹玲  王素芬 《热带海洋学报》2005,24(6):31-37,T0001

南海生态动力学过程复杂,尤其是夏季,在东南季风的影响下,南海西部的上升流、西北部东北向的离岸流对该海区乃至整个南海生态动力学过程都有重要的影响。根据1999—2003年的SeaW-iFS卫星遥感叶绿素a浓度数据,结合2004年在南海北部海洋观测航次实测的叶绿素a浓度数据,分析了南海西北部夏季叶绿素a的分布特征;同时根据海表温度、风场、海面高度等卫星遥感历史资料,探讨了叶绿素a浓度的分布及其对环境因子的响应。结果表明,南海西北部夏季(6—8月)叶绿素a浓度的分布有显著的空间变化:在西部半径达500km低温、强风的半圆形海域范围叶绿素a浓度较高(>0.15mg.m-3),其中位于越南金兰湾东北部有一叶绿素a浓度更高的激流形带(>0.2mg.m-3);而在南海东北部夏季(6—8月)叶绿素a浓度明显偏低(<0.12mg.m-3)。叶绿素a的这种空间分布特征同季风等海洋环境因素之间有密切的关系。对比实测叶绿素a浓度显示,遥感叶绿素a浓度同实测叶绿素a浓度有很好的一致性。  相似文献   

数字航摄仪(DMC)与RC30航摄仪效率分析     

王青山 《测绘与空间地理信息》2010,33(2):220-222

随着我国经济的发展,传统航摄仪已不能满足航空摄影技术快速发展的要求,以DMC为代表的数字航摄仪在影像质量及效率等多方面有很大优势。本文首先简要介绍了DMC与RC30航摄仪,然后分别从航摄飞行、数据后处理、外业像控测量及内业测图几方面,对两种航摄仪的效率进行了分析。  相似文献   

Optical, near-infrared and hard X-ray observations of SAX J1353.9+1820: a red quasar     

C. Vignali  M. Mignoli  A. Comastri  R. Maiolino  F. Fiore 《Monthly notices of the Royal Astronomical Society》2000,314(1):L11-L15

It has recently been suggested that Compton down-scattering may give rise to the broad iron K α line seen in the X-ray spectrum of the Seyfert 1 galaxy MCG–6-30-15. This model suggests that the Comptonizing optically thick plasma surrounding the central X-ray source has a temperature of 0.5 keV and a large radius of 10¹⁴ cm. This offers an alternative to the standard model whereby the broadening of the iron line is solely the result of strong general relativistic effects. We revise the Comptonization model and show that statistically the disc-line model gives a much better fit to the time average of the data analysed by Iwasawa et al. in 1996 and 1999. We also demonstrate that the Comptonization model has problems with simultaneous fitting of the redshifted tail and the core of the line. We show that, in the case of the 1996 data, the best-fitting Thomson depth τ ∼1.6 is consistent with the lack of continuum break, which is constrained to be at photon energies E ≳100 keV. However, the total amount of power in the UV component required to cool the Comptonizing cloud exceeds the Eddington limit. For large black hole masses relativistic effects are important and for small masses the Eddington limit is exceeded by a larger factor. In the case of the 1999 data, the best-fitting Thomson depth is τ ∼5.7; this would imply the existence of a break in the continuum at E ∼16 keV, which is not observed. (However, we point out that the down-scattering break may be diluted if a fraction of the continuum is observed directly.) This rules out Comptonization as the principal mechanism to explain the shape of the Fe K α line in MCG–6-30-15.  相似文献   

火成岩气藏储层预测及勘探技术——以松辽盆地长岭断陷为例   总被引：7，自引：3，他引：4       下载免费PDF全文

匡朝阳  贺日政  高锐  史海英 《地球物理学进展》2009,24(2):602-608

本文以松辽盆地长岭断陷达尔罕断凸带火成岩气藏预测为例,从已钻遇火成岩的钻井资料出发,结合钻井地质信息与地震资料,利用地震特殊处理技术识别火成岩.通过分析结果,研究该区的火成岩分布特征及油气成藏规律,建立判断火成岩的地球物理模式.结合本区域地质资料,预测了本区的火成岩分布,总结出适合本区火成岩构造特征的火成岩气藏识别技术,包括火成岩测井识别技术、火成岩地震剖面反射特征识别技术、火成岩地震相识别技术和地震反演技术等来预测火成岩的空间展布规律,了解火成岩与构造的关系.进而识别火成岩圈闭,总结断陷层系油气成藏组合,为在本区寻找火成岩气藏提供系统分析方法.  相似文献   

桩基检测和加固处理措施   总被引：1，自引：0，他引：1  

韩永昌  石永泉  方煜华 《四川地震》2009,(1)

简要介绍了桩基复合检测、灌浆加固的原理和施工工艺,并阐述了钻孔抽芯过程中常见的孔斜防治问题,结合实例对桩基进行了检测加固说明,分析了事故产生的原因并且提出了应注意的问题。  相似文献