The Influences of Mg~(2+), Ca~(2+) and Mg ~(2+)/Ca ~ (2+) Ratio in Mixed Seawater on the Emergence Rate of Penaeus japonicus Postlarva     

臧维玲  戴习林  江敏  姚庆祯  蔡云龙  罗春芳  徐桂荣  丁福江 《中国海洋湖沼学报》2003,21(1)

ＩＮＴＲＯＤＵＣＴＩＯＮＰｅｎａｅｕｓｊａｐｏｎｉｃｕｓｉｓａｎｅｕｒｏｘｙｂｉｏｔｉｃｐｅｎａｅｉｄｐｒａｗｎ ,ｗｈｏｓｅｐｒｏｐｅｒｓａｌｉｎｉｔｙｒａｎｇｅｆｏｒｇｒｏｗｔｈｉｓ2 0 -30ａｎｄｏｐｔｉｍａｌｓａｌｉｎｉｔｙｒａｎｇｅｉｓ 2 5-30 (ＷａｎｇａｎｄＬｉｕ ,1 991 ;ＷａｎｇａｎｄＹｕ ,1 999) .Ｉｔｈａｓｇｒｅａｔｏｓｍｏｒｅｇｕｌａｔｉｏｒｙｃａｐａｃｉｔｙ (ＭａｎｔｅｌａｎｄＦａｍｅｒ,1 983) .Ｂｕｔｉｔｓｂｅｓｔｅｎｖｉｒｏｎｍｅｎｔｆｏｒｒｅｐｒｏｄｕｃｔｉｏｎａｎｄｄｅｖｅｌ…  相似文献   

基于Hapke和Shkuratov模型的斑岩铜矿蚀变带混合波谱研究     

代晶晶 《地质与勘探》2013,49(3):505-510

矿物光谱混合模型研究对于蚀变带蚀变矿物的信息提取具有重要意义。本文基于目前两种主流的非线性光谱混合模型Hapke和Shkuratov模型,通过对两者特性的对比分析,提出了一种综合利用这两种模型进行矿物或岩石光谱混合模拟的思路,并针对斑岩型铜矿典型蚀变分带现象,进行钾化带、绢英岩化带、泥化带、青磐岩化带等典型蚀变带矿物组合光谱的模拟实验。本研究提取结果可以为斑岩铜矿蚀变带研究提供理论依据。  相似文献   

桂林市混合土层CFG桩地基加固处理设计与施工技术研究     

张伟  苏阳  刘之葵  方宗正  白显嵩  蒋文德  李玉子免 《矿产与地质》2013,(5):424-428

本文根据桂林市混合土的工程特性,主要阐述了桂林市混合土层CFG桩地基加固机理、设计计算、施工以及处理技术的应用设计,并介绍了在施工方面的工艺流程及应该注意的问题。对桂林市岩溶区混合土层的地基加固处理,CFG桩是一种较为理想的地基处理技术。  相似文献   

Mitigation of levee failures using deep mixed columns and geosynthetics     

《Geomechanics and Geoengineering》2013,8(1):49-55

Stability of levees is critical to the safety of human and structures, especially at high water levels. Levees may fail due to the existence of soft soil foundations or seepage of water through the levees or rapid drawdown. Deep mixing technology has been considered one of the good alternatives to solve foundation and seepage problems while geosynthetics can be used to stabilize slopes during rapid drawdown. Studies have shown that deep mixed columns and geosynthetics can increase the stability of highway embankments over soft soils. In those studies, however, no ponding water exists on either side of the embankment, which is not the case for levees. Experimental studies have shown that deep mixed columns under a combination of vertical and horizontal force could fail due to shear or tension/bending or rotation. A finite difference method, incorporated in the FLAC (Fast Lagrangian Analysis of Continua) Slope software, and a limit equilibrium method (specifically Bishop's method), incorporated in the ReSSA software, were adopted in this study to investigate the stability of the levee with ponding water or under rapid drawdown. In this study, deep mixed columns were installed in continuous wall patterns, which were modeled as 2D deep mixed walls. Geosynthetic layers were modeled using cable elements with grout properties between geosynthetic and soil in the numerical analysis. Mohr-Coulomb failure criteria were used for the levee, the soft soil, and the deep mixed walls. The stability of a levee at different stages (end of construction, average service condition, high water surge, and rapid drawdown from the service condition and the highest water level condition) was examined. The study clearly demonstrated that the deep mixed walls can enhance the stability of the levee by providing shear/moment resistance and hindering seepage through the levee and geosynthetics can enhance the riverside slope stability of the levee by providing tensile resistance to the soil.  相似文献   

柴北缘上古生界混合沉积特征及控制因素     

陈世悦  毕明威  孙娇鹏  张跃  庄毓凯  刘金  汪峰  马帅 《地质通报》2016,35(203):282-292

柴北缘晚古生代发育多种成因机理各异的混积岩与混积层系。混积岩分为蚀源型砂砾岩,碳酸盐岩-粗陆源碎屑混积岩,泥灰岩(灰泥岩)与含化石泥岩三大类。混积层系在不同环境中均有出现,混积相可划分为混积砂砾质碎屑海岸相、混积低能海岸相、混积台地、混积陆棚4类。在此基础上对各类混积岩、混积层系进行了沉积环境、形成机制解释,归纳出3种不同时期的混积相组合并建立沉积模式。构造运动、海平面升降、气候及古坡角的共同作用导致该区混合沉积普遍发育。其中,加里东构造带的存在及近物源沉积是粗碎屑与生屑颗粒混合的先决条件,海平面频繁变化与极缓的古坡角是该区混积岩、混积层系高频发育的直接原因。  相似文献   

湘西花垣排碧寒武系花桥组上段—车夫组沉积环境的探讨   总被引：1，自引：0，他引：1  

梁薇  牟传龙  周恳恳  葛祥英 《地质论评》2012,58(2):259-267

湘西排碧位于中上扬子陆块的东南缘,前人认为在寒武纪第三世时期该地区位于以各种类型的"碳酸盐重力流沉积"发育为显著特征的"台缘斜坡相带"内,其主要岩石类型为泥质条带灰岩及砾屑灰岩。本文通过对花桥组上段—车夫组典型沉积物的岩石组分及沉积构造进行详细研究,发现条带灰岩并非泥质条带灰岩,而是由灰岩条带——颗粒灰岩、泥晶灰岩与粉砂质条带——粉砂质灰岩、纹层状含炭质粉砂质灰岩互层组成,表现出内源碳酸盐沉积物与陆源碎屑沉积物混积以及陆棚环境沉积物的典型特征。砾屑灰岩及伴生岩石组合发育丘状(洼状)交错层理等众多风暴成因的沉积构造,为具有不同风暴沉积序列的风暴沉积物。此外,花桥组上段—车夫组沉积物中含各种藻类等浅水生物及大量三叶虫骨刺。因此,认为花桥组上段—车夫组的沉积环境应为正常浪基面以下、风暴浪基面以上,受周期性强风浪作用影响的混积陆棚环境。  相似文献   

基于混合像元分解的海坛岛植被覆盖度因子研究     

白霎 《福建地理》2013,(4):81-86

在USLE／RUSLE中,降雨侵蚀力与地表植被覆盖度因子具有季节变化特征．本研究考虑到两者的时空耦合性,采用基于混合像元分解的计算-y法,得到了海坛岛不同月份的地表植被覆盖度因子C。值（第i月的地表植被覆盖度因子值）和不同地类的年植被覆盖度因子C值,为岛内土壤侵蚀预报和水保工作提供参考．对第i月的地表ND啊值与年C／Ci值进行分析,发现它们呈现较好的线性关系,用SPSS软件进行回归分析得到两组线性回归参数．年C值与11月份的地表NDVI拟合程度最好,NDVIi与C1值的拟合程度好于年C值与NDVLi最后得到海坛岛通用的Ci值估算模型G=1．007—1．119-ND％,该模型的决定系数达到0．8,可用于计算岛内各月份的Ci值．  相似文献   

The potential of spectral mixture analysis to improve the estimation accuracy of tropical forest biomass     

Tyas Mutiara Basuki  Andrew K. Skidmore  Patrick E. van Laake  Iris van Duren  Yousif A. Hussin 《国际地球制图》2013,28(4):329-345

A main limitation of pixel-based vegetation indices or reflectance values for estimating above-ground biomass is that they do not consider the mixed spectral components on the earth's surface covered by a pixel. In this research, we decomposed mixed reflectance in each pixel before developing models to achieve higher accuracy in above-ground biomass estimation. Spectral mixture analysis was applied to decompose the mixed spectral components of Landsat-7 ETM+ imagery into fractional images. Afterwards, regression models were developed by integrating training data and fraction images. The results showed that the spectral mixture analysis improved the accuracy of biomass estimation of Dipterocarp forests. When applied to the independent validation data set, the model based on the vegetation fraction reduced 5–16% the root mean square error compared to the models using a single band 4 or 5, multiple bands 4, 5, 7 and all non-thermal bands of Landsat ETM+.  相似文献   

THE NEED FOR PHYSICAL GEOGRAPHY     

《The Professional geographer》2013,65(2):141-148

As a viable intellectual and professional pursuit with well defined goals, physical geography is alive and kicking but demands greater commitment from the geography profession generally. In particular, physical geographers are exhorted to be thoroughly trained in the subject matter and methodology of their own and related disciplines, to be integrative in the acquisition, analysis and interpretation of data, to be predictive in their work, and to be proud of the role that they can play in serving society's environmental needs.  相似文献   

On the well‐posedness of some mechanical variational problems     

P. Royis 《国际地质力学数值与分析法杂志》2006,30(3):255-269

The paper aims to establish the existence and uniqueness of the solution of some variational problems constituting the basis of finite element modellings encountered in mechanics and civil engineering. And indeed, by expanding to the approximate problems coming from the space discretization, such theoretical results contribute to strengthen the robustness of the modelling softwares and the quality of their numerical results. More particularly, three kinds of mixed variational problems involving rheological non‐linearities are considered here: the evolution problems of incompressible continua (solids or fluids) subjected to quasistatic small transformations, the problems of hydromechanical coupling and those coming from quasistatic large transformations of continua. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献