有害藻华治理过程中改性粘土对仿刺参(Apostichopus japonicas Selenka)稚参的影响   总被引：1，自引：1，他引：0  

王志富  俞志明  宋秀贤  曹西华  刘楷 《海洋与湖沼》2014,45(2):233-238

本文以仿刺参(Apostichopus japonicas Selenka)稚参为实验对象,研究了改性黏土治理有害藻华技术对仿刺参稚参的影响。96h急性毒性试验结果表明,改性黏土对仿刺参稚参的半致死浓度(LC50)为6.01g/L;安全浓度为0.601g/L,高于在现场时的使用浓度0.1g/L;慢性毒性试验显示改性黏土对仿刺参稚参成活率和体重增长率无明显影响;不同浓度的改性黏土添加组中,发现仿刺参稚参的体壁组分(水分、灰分、总糖、总脂和粗蛋白)含量变化不大,改性黏土的加入对减少仿刺参稚参的种内竞争有一定积极作用。另外,针对仿刺参稚参食用包括改性黏土在内的底层颗粒物的现象,考察了不同实验组仿刺参稚参体壁中铝的含量,分析结果显示各实验组与对照组没有显著差异。在此基础上,考察了改性黏土有效去除有害藻华的体系中仿刺参稚参的生长情况,发现与对照组相比,改性黏土有效地去除了有害藻华,还明显降低了仿刺参稚参的死亡率。因此,改性黏土是一种有效治理仿刺参养殖水体有害藻华、对养殖生物无负面影响的藻华治理技术。  相似文献   

悬浮液中硫酸根对改性粘土去除藻华生物效率的影响     

刘扬  俞志明  曹西华  宋秀贤  张雅琪  林勇新 《海洋与湖沼》2014,45(4):734-740

本文研究了改性粘土悬浮液中硫酸根对其去除藻华生物效率的影响,通过Zeta电位、沉降速率和粒径分布等分析了改性粘土对藻华生物的去除效率,探讨了硫酸根与改性粘土的作用机制。结果显示:改性粘土对抑食金球藻(Aureococcus anophagefferens)的去除效率随悬浮液中硫酸根浓度的增加呈现先降低后升高的趋势,改性湖北土和改性江苏土对抑食金球藻去除率较低时(40%)的硫酸根浓度分别为6.46×10–3—2.42×10–1mol/L和6.46×10–3—2.42×10–2mol/L;改性粘土颗粒的Zeta电位随着硫酸根浓度的增加而降低,然后保持相对稳定;悬浮液中改性粘土颗粒的沉降速率和中值粒径D50呈现先增加后降低的趋势,对于改性江苏土,在硫酸根浓度为2.42×10–2mol/L时颗粒的沉降速率最大。综上所述,悬浮液中硫酸根主要通过降低粘土颗粒表面电荷密度、桥联改性粘土组分和影响粘土颗粒分散性等作用影响改性粘土对藻华生物的去除效率。  相似文献   

氟——我国矿产资源开发利用的新矿种     

马建明  冉启洋 《国土资源情报》2014,(4):13-16

氟是一种非金属化学元素,中国氟化工行业绝大多数产品是以萤石作为传统原材料。当前我国矿产资源管理中与氟有关的矿种只有萤石一种。磷矿中伴生氟是最具利用价值的氟资源之一,我国磷矿资源中蕴藏着巨大的（伴生）氟资源,从资源远景看,磷矿石中伴生的氟资源远多于萤石。磷矿中的伴生氟以碳氟磷灰石的形式存在,目前伴生氟资源已经在贵州等地得到开发利用。管理好、利用好（伴生）氟资源既具有资源意义,又具有经济意义和环境意义,建议把（伴生）氟资源作为一种新的矿种进行管理,促进（伴生）氟资源的开发利用,为社会造福。  相似文献   

Onshore-offshore gradient in reductive early diagenesis in coastal marine sediments of the Ria de Vigo, Northwest Iberian Peninsula     

K.J. Mohamed  D. ReyB. Rubio  M.J. DekkersA.P. Roberts  F. Vilas 《Continental Shelf Research》2011,31(5):433-447

Early diagenetic modification of magnetic properties is an important process in marine sediments, but temporal and spatial variability of diagenetic processes have rarely been reported for recent coastal sediments. The magnetic properties of sediments from the Ria de Vigo (NW Spain) define a marked three-part zonation with depth. The uppermost zone is magnetically dominated by (titano-)magnetite. In the intermediate zone, rapid down-core dissolution of (titano-)magnetite increases the relative influence of high-coercivity magnetic minerals, which react more slowly during reductive dissolution than (titano-)magnetite. This zone is characterized by the ubiquitous occurrence of framboidal iron sulphides. Pyrite is the dominant iron sulphide, but framboidal ferrimagnetic greigite is also frequently observed in association with pyrite. The lowermost zone is characterized by an almost complete depletion of magnetic minerals associated with progressive reduction of detrital iron oxides with depth. This zonation is controlled by organic matter diagenesis, which varies with water depth and wave-induced sediment resuspension and organic matter reoxidation in the water column. This leads to a shallowing and thinning of each zone with more intense reductive diagenesis toward the interior of the ria. Such a zonation seems to be a common feature in shallow water marine environments. If preserved, the described zonation and its spatial variability provide a potential tool for detecting estuarine-like environments in the geological record. Magnetic detection of current or past reductive conditions also has important implications for assessing paleoenvironmental proxies that are sensitive to diagenetic redox state.  相似文献   

昆明黏性土动力特性试验研究   总被引：2，自引：0，他引：2  

毛尚礼  余湘娟  张富有 《地震工程与工程振动》2011,31(2):170-174

对昆明地区黏性土进行室内的共振柱试验和动三轴试验,初步研究了该地区黏性土的动力特性,得出了不同初始固结比下黏性土的动强度曲线,比较了黏土与粉质黏土的动强度受固结应力比的差异,并对黏性土的动强度与破坏时其振动周数之间的关系曲线进行了拟合,给出了其数学表达式根据试验所得动强度包线的特征和动强度参数,分析了黏性土强度参数的变...  相似文献   

柴达木盆地大浪滩地区表层芒硝的形成时代及环境意义     

马妮娜  郑绵平  马志邦 《地质学报》2011,85(3):433-444

通过对柴达木盆地大浪滩地区的两次实地勘查,发现小梁山多处可见芒硝—碳酸盐粘土互层的露头,选取了完整沉积的D26剖面进行研究。比较盐湖学的研究表明,芒硝是典型的冷相盐类矿物;而碳酸盐粘土和石膏则反映了相对温暖潮湿和温暖的环境。本文通过对芒硝—碳酸盐粘土互层的矿物鉴定,石膏的铀系不平衡法定年,以及结合碳酸盐粘土的碳氧同位素分析,首次揭示出大浪滩地区在倒数第二次冰期（MIS 6阶段）前后经历了偏暖潮湿期（＞195.1 ka BP）→寒冷干旱期（195.1 ~ 169.9 ka BP）→偏暖湿期（169.9 ka BP ka BP）→冷暖交替时期（169.9 ka BP ~ 118 ka BP）→偏暖湿期（118 ka BP）的气候演变序列。经与黄土剖面,深海氧同位素和区域研究资料的对比表明,自中晚更新世以来,大浪滩地区不仅受到区域地质活动的影响,也与全球的气候变化同步响应。  相似文献   

鄂尔多斯盆地东南部二叠系物源分析   总被引：9，自引：1，他引：8  

屈红军  马强  高胜利  梅志超  苗建宇 《地质学报》2011,85(6):979-986

近几年鄂尔多斯盆地东南部上古生界陆续发现新的天然气区带,显示出巨大的勘探潜力,因此对盆地东南部二叠系物源的研究对于确定储集砂体展布规律具有重要价值。以钻测井、岩心及周边露头资料为基础,通过露头剖面古流向测定、重矿物分析、边缘相分析、相带分析的方法,确定了研究区二叠系的物源方向;研究认为鄂尔多斯盆地东南部二叠系山西组与石盒子组物源可分为北北东、北北西及南部三个方向,以延安为中心区域属于汇水区;山2段南部物源影响范围较大,影响到延安以北区域;盒8段北部物源范围较大,越过了延安,相应的南部物源范围后撤。  相似文献   

Multi-dimensional chemo-osmotic consolidation of clays     

Yu-Chao Li  P.J. Cleall  H.R. Thomas 《Computers and Geotechnics》2011

A model of chemo-osmotic consolidation of clays in multi-dimensional domains is presented, with volumetric strains induced by both changes in the chemistry and osmotically driven pore water flow considered. Three fully coupled governing equations considering force equilibrium, pore water transport and chemical transport are presented and solved using the transient finite element method. The proposed approach is verified via consideration of chemo-osmotic consolidation of a compacted clay landfill liner and then applied to investigation of a hypothetical case with a local leachate leak in the compacted clay liner. An assessment of the impact of the two-dimensional nature of the system is made. The consolidation process is found to be dominated by osmotic consolidation in the early stages and subsequently by chemical consolidation. It is found that the surface settlement and the leachate concentration in the compacted clay liner may be highly overestimated by a one-dimensional analysis. Moreover, the peak negative excess pore pressure predicted by the two-dimensional solution remains in a shallow region under the leak while in the one-dimensional solution it moves progressively downwards.  相似文献   

Simulation of yielding and stress–stain behavior of shanghai soft clay     

Maosong Huang  Yanhua Liu  Daichao Sheng 《Computers and Geotechnics》2011

In this paper, a simple bounding surface plasticity model is used to reproduce the yielding and stress–strain behavior of the structured soft clay found at Shanghai of China. A series of undrained triaxial tests and drained stress probe tests under isotropic and anisotropic consolidation modes were performed on undisturbed samples of Shanghai soft clay to study the yielding characteristics. The degradation of the clay structure is modeled with an internal variable that allows the size of the bounding surface to decay with accumulated plastic strain. An anisotropic tensor and rotational hardening law are introduced to reflect the initial anisotropy and the evolution of anisotropy. Combined with the isotropic hardening rule, the rotational hardening rule and the degradation law are incorporated into the bounding surface formulation with an associated flow rule. Validity of the model is verified by the undrained isotropic and anisotropic triaxial test and drained stress probe test results for Shanghai soft clay. The effects of stress anisotropy and loss of structure are well captured by the model.  相似文献   

Numerical analysis of an embankment built on soft soil reinforced with deep mixing columns: Parametric study     

Paulo J. Venda Oliveira  João L.P. Pinheiro  António A.S. Correia 《Computers and Geotechnics》2011

The behaviour of an embankment built on normally consolidated soft soil reinforced with deep mixing columns is studied using a coupled soil–water formulation. The numerical predictions are analysed in terms of settlements, increments in vertical effective stresses and excess pore pressures. Firstly, the effectiveness of the use of deep mixing columns is studied. Afterwards, a parametric analysis is performed to study the influence on the soil-columns system of the replacement ratio (columns’ spacing), the deformability of the embankment and columns, and the coefficient of vertical permeability of the columns.  相似文献