Comparison of the defluoridation efficiency of calcium phosphate and chitin in the exoskeleton of Antarctic krill     

WANG Zhangmin  YIN Xuebin 《极地研究(英文版)》2012,(3):149-154

Calcium （Ca）, phosphorus （P）, and chitin are the main components of the exoskeleton of krill. Defluoridation of a solution of sodium fluoride （NaF） using calcium phosphate （Ca3（PO4）2） and chitin as defluoridation agents was studied. Orthogonal experiments were designed to find the optimum reaction conditions for defluoridation, to obtain the maximum defluoridation efficiency and fluoride removal capacity of calcium phosphate and chitin. At the same time, a comparison of the capacity of the two defluoridation agents was made. The results suggest that calcium phosphate has a far greater capability than chitin for the removal of fluoride （F） from water under similar reaction conditions. It is also suggested that Antarctic krill is likely to adsorb fluoride via compounds such as calcium phosphate, hydroxyapatite, and other compounds of Ca and P with the general form （Ca, X）x（PO4, HPO4, Y）y（OH, Z）z, in addition to chitin.  相似文献   

内蒙古二连浩特市切实加强古生物化石管理保护工作     

《华北国土资源》2012,(4):24

近年来,二连浩特市采取多项措施着力强化古生物化石保护,使古生物化石管理保护工作从无序到有序,逐步走上规范化道路。他们及时反应,注重发掘现场保护。同时,注重干部群众教育,使古生物化石  相似文献   

汶川地震地震动的扭转分量反应谱     

李琳  罗奇峰 《国际地震动态》2012,(6):154-154

计算地震动转动分量反应谱的方法主要有反应谱定义法,功率谱反应谱转换法以及Rutenberg和Heidebrecht (1985)提出的一种由平动反应谱间接得到转动反应谱的方法.反应谱定义法就是首先合成地震动转动分量的时程,然后计算各个自振周期的结构在转动时程作用下的最大反应,不同周期结构的最大反应连接起来便可得到与这条时程相应的反应谱,这是获得反应谱的一种常用方法.  相似文献   

北京平原区地震工程地质条件及地震效应     

彭艳菊  吕悦军  施春花  张力方 《国际地震动态》2012,(6):145-145

1 资料与方法 收集了研究区近10年来998个场地钻探数据和500组土动力学实验数据,进行工程地质分区;然后统计得到研究区常见土类剪切波速随深度的变化规律,以及动剪切模量和阻尼比与剪应变的关系,建立场地力学分析模型,采用一维等效线性化方法进行地震反应分析计算,确定不同地震强度下基于场地条件的地震影响分布图.  相似文献   

多维激励下曲线梁桥地震反应分析     

付莉  罗奇峰 《国际地震动态》2012,(6):147-147

大量震害表明,地震动除有3个方向的平动分量外,还有绕3个轴的转动分量.以往对曲线梁桥这种不规则结构的抗震分析主要集中在平动分量上,随着地震动转动分量理论的进步,有必要在大跨曲线梁桥的抗震分析中引入转动分量的影响问题.  相似文献   

岭澳核电站地震监测系统     

陈志高  吴雄伟  姚立民 《大地测量与地球动力学》2012,32(Z1):170-172

介绍岭澳核电站地震监测系统,该系统可实时监测地震加速度随时间的变化过程,自动进行地震检测、事件的识别、数据采集与存储.当检测到地震事件后,立即向主控室发送报警信号,计算加速度响应谱等.  相似文献   

渗透性反应墙（PRB）对地下水石油污染修复技术研究     

于立娜  刘仁平 《黑龙江国土资源》2012,(3):60-60

PRB技术作为一种新兴的地下水污染原位修复技术,与其他地下水污染的修复技术相比,主要优点是对污染物具有良好的去除效果,且不需要对地下水进行抽泵和回灌;PRB系统中的反应介质消耗很慢,有几年甚至几十年的处理能力,且除了须长期监测外几乎不需要运行费用。  相似文献   

考虑轨道约束的连续梁拱桥地震反应及减震控制研究          下载免费PDF全文

石岩  赵翔宇  焦应乾  刘云帅  张胶玲 《世界地震工程》2022,38(1):148-157

以一座大跨度单线铁路连续梁拱桥为背景,建立了考虑轨道约束和相邻构件碰撞效应的动力分析模型;通过输入40组水平双向地震动记录进行非线性时程分析,探究轨道约束和拱肋对桥梁地震响应的影响,采用"减震榫-拉索限位器"与"自恢复耗能支撑(SCEDB)-屈曲约束支撑(BRB)"控制水平向地震反应,并对比两种组合减震控制系统的减震效...  相似文献   

一种简单的岩体地下洞室地震安全评价方法   总被引：5，自引：2，他引：3  

李海波  刘博  吕涛  许文锋  杨建宏  夏祥  周青春 《岩土力学》2009,30(7):1873-1882

提出了动应力集中因子代表值的概念,以合理反映地震荷载作用下地下洞室围岩的动应力集中程度,并将动应力集中因子代表值,作为洞室地震响应的关键特征来衡量洞室地震响应的大小。应用显示有限差分法,讨论了地震动加速度幅值、洞室埋深、围岩岩体级别、衬砌混凝土厚度、衬砌混凝土强度等级与动应力集中因子代表值的相关关系。研究表明,动应力集中因子代表值与这5个因素均近似呈线性关系。在此基础上给出了有（无）衬砌支护结构两种情况的地震安全评价公式,提出了岩体地下洞室的地震安全评价方法。应用提出的评价方法,分别对唐山余震地震作用下溪洛渡水电站超大型地下洞室群的地震安全性进行了评价,所得结果与Dowding-Rozen及Sharma-Judd的评价方法结果一致。分析还表明,文中提出的岩体地下工程的地震安全评价方法的评价结果是偏于安全的。  相似文献   

Sedimentation and morphological changes at Yuantuojiao Point,estuary of the North Branch,Changjiang River   总被引：3，自引：1，他引：2  

XIE Li  ZHANG Zhenke  ZHANG Yunfeng  WANG Yaping  HUANG Xianjin 《海洋学报(英文版)》2013,32(2):24-34

The North Branch, separated by the Chongming Island, was once the main channel in the estuary of the Changjiang River. Reclamation and a decrease in runoff to the North Branch had led to the narrowing and shallowing of the channel. The Yuantuojiao Point is located at the intersecting point connecting the North Branch of the Changjiang River and the Jiangsu coastline. Erosion cliffs are developed between the typical silty-muddy tidal flat and the salt marsh occupied by Spartina alterniflorea, and this has changed rapidly over the past few years. The sediment grain size analysis results of the surficial and two core samples indicate that the Yuantuojiao Point tidal flat experienced continuous accretional processes. Based upon 137 Cs analysis results of the YT and YY Cores sampled from the tidal flat at the Yuantuojiao Point, the average sedimentation rate of the YT Core was 2.30 cm/a from 1963 to 2007, and 2.38 cm/a from 1954 to 2007 for the YY Core. The sedimentation rates of both core locations have declined since the 1960s corresponding to the seaward reclamation at the Yuantuojiao Point. The average sedimentation rates at the Yuantuojiao Point were similar to that of the silty-muddy tidal flat at the northern Jiangsu coast, but lower than that of the south of the Changjiang River Estuary. According to field morphological investigations from 2006 to 2008 on the salt marsh at the Yuantuojiao Point, cliffs retreated markedly by storm surges and disappeared gradually because of the rapid sedimentation on the silty-muddy tidal flat. The maximum annual retreat reached 10 m. The recent sedimentation and morphological changes of the Yuantuojiao Point tidal flat not only displayed the retreat of the salt marsh and the disappearance of cliffs, but also was accompanied by rapid sedimentation of the silty-muddy tidal flat and the salt marsh, indicating the responses to the tidal currents, storm surges, Spartina alterniflorea trapping sediments and large-scale reclamation. The sediment grain size and their trends, southward coastal flow, and sandspits of the longshore bars suggest that the main sediment source at the Yuantuoijao Point, estuary of the North Branch was possibly from the Changjiang River before 1958, since then, it has been from the south of the submarine radial sand ridges of the southern Huanghai Sea (Yellow Sea).  相似文献