改性蒙脱石吸附Pb^2＋、Hg^2＋的实验研究   总被引：8，自引：0，他引：8  

王毅  王艺  王恩德 《岩石矿物学杂志》2001,20(4):565-567

对蒙脱石进行化学改性后生成的硫代蒙脱石热稳定性好，并且对金属离子Pb^2 、Hg^2 有很好的吸附性能，是一种处理污水中有害金属离子有效的矿物材料。  相似文献   

Ground Stabilization for foundation and excavation construction in Florida karst topography     

L. J. Almaleh  J. D. Grob  R. H. Gorny 《Environmental Geology》1993,22(4):308-313

The construction of additional facilities at the Florida Power Corporation's Crystal River Energy Complex required an extensive stabilization program to construct foundations for approximately one half mile of cooling towers. This paper presents an overview of the techniques and methods used in the construction of additional facilities at the Crystal River Generating Station. Excavations for intake and discharge structures were to be more than 20 ft below the water table. Cooling tower foundations were constructed on extensively solutioned Florida limerock located on the central Gulf Coast of Florida. Hybrid ground modification techniques were used to stabilize soft or loose soils and solution features in the underlying limerock, allowing mat and spread footing foundations to be used for most of the facility. The ground modification techniques were used to detect, collapse, densify, and fill solution features below the structure foundations. The bearing capacity after ground modification was verified by field load tests. Subsurface investigations indicated that sheet pile excavations with grouted seals were the optimal technique for cofferdam excavations in the limerock formation. Existing collapsed caverns were encountered during construction of the cofferdam for the intake structure and the adjacent discharge structure, requiring a fast-track design change, considerable field coordination, and daily modifications to accommodate the varied conditions encountered. Tied-back soldier pile cofferdam construction was combined with grouting, underwater excavation, and a massive, unreinforced, concrete tremie slab with grouted anchors, and installed off a barge to provide a dewatered excavation. This project involved the use of hybrid soil-rock anchors to anchor one of the largest continuous placement tremie seals installed in Florida. Other excavations used sheeting and grouting of the underlying limerock formation to provide a dewatered excavation. Ground modification techniques were used to treat a filled cavern discovered in the corner of one discharge structure. The entire construction of this facility was confined to a narrow work area by existing wetlands and the generating station discharge canal. Strict environmental restrictions required by the regulatory agencies to prevent impacts to the surrounding area were imposed on this project.  相似文献   

四阶矩准正态分布和三阶矩剪切近似的验证   总被引：1，自引：0，他引：1  

张强  胡隐樵 《大气科学》1994,18(4):396-404

本文利用近地面层大气湍流量的观测资料对四阶矩的准正态分布假定和三阶矩的剪切近似进行了实验验证。结果表明，四阶矩能够较好地符合准正态分布假定；三阶矩不仅完全满足剪切近似，甚至还可以对剪切程度进一步加强，并且得到了一系列剪切近似的加强修正系数。  相似文献   

Oxidation Modification of Polyacrylonitrile-Based Carbon Fiber and Its Electro-Chemical Performance as Marine Electrode for Electric Field Test     

Xuerong Zai  Ang Liu  Yuhua Tian  Fanggang Chai  Yubin Fu 《中国海洋大学学报(英文版)》2020,19(2):361-368

A novel sensor for ocean electric field testing has been fabricated by polyacrylonitrile-based on carbon fibers with electro-chemical oxidation.The surface profile characteristics of the carbon fibers were characterized by scanning electron microscope,Fourier transform infrared spectra and contact angle.Cyclic voltammetry and Tafel curves have been used to study its electro-chemical performances.Two identical electrodes in sea water as the electric field sensor will swiftly respond to applied electric field which causes positive and negative ions to move in opposite direction,resulting in a electric potential difference(ΔE).Test result indicates that the offset potential is typically below 1 m V with a drift of 60-170μVd^-1.Typical self noise level is 1.07 nV√Hz^1/2@1 Hz.The electric field response indicates that the modified electrode pair shows better response to AC sine signal of amplitude and frequency(5 mV and 1 mHz)respectively than its blank.The electric field response model of the modified electrodes is creatively presented according to its electric double layer capacitance and Faraday pseudo-capacitance.Many advantages of the carbon fiber electric field electrode will make it have potential application prospect.  相似文献   

FPSO结构低周疲劳寿命计算方法研究          下载免费PDF全文

胡奇  解德 《海洋工程》2014,32(6):24-30

FPSO在海洋环境中频繁地进行装载与卸载操作,使FPSO船体结构产生较大的应力幅值,尤其是承受货油压力的内底纵骨。由于局部的应力集中,应力幅值超过材料的屈服强度,其装卸载次数小于104时,结构将产生低周疲劳。研究一种新的计算方法,根据Neuber假设进行塑性修正,通过应变范围得到伪热点应力范围,并确定热点应力与伪热点应力之间的关系。推导出一种新的S-N曲线作为低周疲劳的设计曲线,以伪热点应力作为计算量来预测低周疲劳寿命,降低了船体结构低周疲劳寿命计算的难度。  相似文献   

浅壳与上地幔地震竖向加速度谱阻尼修正系数模型          下载免费PDF全文

张洪博  刘名吉  康莉莉 《世界地震工程》2021,(3):155-169

本文基于日本KiK-Net,K-Net台网及汶川地震中6 000余条浅壳与上地幔地震竖向加速度记录,分场地类型建立了包含阻尼比和谱周期两个参数的阻尼修正系数模型,用以调整无震级和震源距信息的设计谱。基于固定效应模型对阻尼修正系数对数值及阻尼比对数值的三次多项式进行线性回归得到模型表达式,基于随机效应模型对阻尼修正系数模型的残差及残差的标准差进行分离,分析震源、路径以及场地效应对模型误差的影响。研究结果表明:高阻尼长周期震源效应引起的残差大于其他效应引起的残差;场地效应引起的残差小于其他效应引起的残差。对模型残差的标准差及阻尼比对数值进行线性回归,回归方程易于计算模型残差的标准差。  相似文献   

Raman spectroscopic detection of key biomarkers of cyanobacteria and lichen symbiosis in extreme Antarctic habitats: Evaluation for Mars Lander missions     

Howell G.M. Edwards  Caroline D. Moody  David D. Wynn-Williams 《Icarus》2005,174(2):560-571

With proposals that micro-miniaturised Raman spectrometers could soon be part of a suite of analytical instrumentation on the surface of Mars, it is critically important to examine the spectral information that could be forthcoming from attempts to determine key molecular biosignatures under the hostile conditions of extra-terrestrial planetary exploration. Current approaches include the analysis of genuine martian geological material in the form of the SNC class meteorites, the formulation of simulated martian regoliths and the examination of putative martian terrestrial analogues; the latter provide the basis of this paper in the form of Antarctic extremophile habitats. In particular, specimens of epilithic, chasmolithic and endolithic lichen and cyanobacterial colonies sampled along a progressively worsening transect towards a “limits of life” situation, beyond which survival of organisms becomes impossible, provide what is arguably the best terrestrial proving-ground for prototype Raman spectrometers for martian exploration. Here, we report the results of experiments on these extant Antarctic extremophile colonies using a range of Raman excitation wavelengths and experimental conditions and also include a compilation of molecular spectral biosignatures, which may be considered as a suitable database for recognition of bioorganic modification of geological strata.  相似文献   

基于时空信息的应急案例库系统关键技术研究     

李欣 《测绘与空间地理信息》2016,(8):12-16

首先对应急决策的流程进行了分析,总结出案例对于应急决策的支撑作用主要体现在可以增强决策的科学性,缩短决策的时间。然后,总结分析了应急案例库系统的总体结构,以及实现的关键技术,包括应急案例的时空表达,基于时空关系的应急案例选取,基于时空相似性的应急处置方案修正,应急案例的评价,应急案例的系统学习,并在实践中进行了应用,取得了较好的应用效果。  相似文献   

改性桑树叶吸附材料对废水中Cd(Ⅱ)的吸附性能研究   总被引：2，自引：1，他引：1  

许芳  张利平  程先忠  魏孝 《岩矿测试》2016,35(1):62-68

桑树叶富含植物多酚和黄酮类化合物,表面存在着大量羟基、羧基功能基团,在一定条件下通过络合作用或静电作用能与重金属离子发生吸附作用。但由于生物质中普遍存在着可溶性单宁,直接使用生物质吸附废水中的镉,去除效果不够理想。本文以生物质桑树叶为原料,经沸水蒸煮去除小分子和稀磷酸酸化改性,提高桑树叶的吸附容量,制备成活性吸附材料去除废水中的Cd(Ⅱ)。吸附条件实验表明:在p H=4.0时改性桑树叶对Cd(Ⅱ)的吸附效果最佳,当Cd(Ⅱ)初始浓度为150 mg/L,改性桑树叶的添加量为6 g/L时吸附率可达96.58%。化学改性桑树叶对Cd(Ⅱ)的吸附过程符合准二阶动力学方程,Langmuir等温吸附模型能更好地描述改性桑树叶的吸附行为,Cd(Ⅱ)最大吸附量为30.58 mg/g,与前人报道的吸附量显著提高。本项研究的改性桑树叶吸附材料价廉易得,为废水中镉的处理提供了一个新的方法。  相似文献   

基于引力模型的中心镇空间联系测度研究——以浙江省金华市25个中心镇为例   总被引：6，自引：5，他引：1  

李陈  靳相木 《地理科学》2016,36(5):724-732

根据中心镇之间经济社会要素空间流动特征,对引力模型和断裂点公式进行改进与整合,形成基于引力模型的中心镇空间联系测度方法体系,并将其应用于金华市25个中心镇空间联系强度和空间引力范围的定量测度。结果显示：① 金华市中心镇空间联系强度呈现出明显的组团化空间格局,中心镇发展可进行“两轴线、四组团”的空间整合;② 市域中心镇空间联系强度具有显著的空间分异规律,需采取差别化的措施促进中心镇协同发展;③ 金华市中心镇空间引力范围差异较大,中部中心镇组团空间引力范围最大,东南部、西部组团次之,北部组团最小;④ 中心镇与断裂点之间的距离关系,可作为判断中心镇组团内核心中心镇及关键节点中心镇的重要依据。  相似文献