地电化学提取法的理论与实验研究   总被引：6，自引：0，他引：6  

李金铭  卢军 《地学前缘》1998,5(2):208-216

根据离子溶液电化学的基本性质和稳定电流场的基本理论,通过理论计算和物理模拟实验,指出：离子在外电场作用下,由所在地点迁移至接收电极所需时间与多种因素有关,当外界条件一定时,加大供电电流强度可减少接收时间;离子淌度值很小,由实测时量曲线计算出的ｕｉ值,一般不超过几个ｃｍ２·ｈ－１·Ｖ－１单位,因此欲提取深部离子,即使在最有利条件下也是非常困难的;由不同供电电流强度测出的时量曲线,计算得到的淌度值是相等的,因此改变供电电流强度并不能改变离子淌度值,但当围岩介质的颗粒度较大时,可使离子淌度值变大;离子的迁移质量与供电电量Ｑ＝Ｉ·ｔ成正比,因此在供电电流强度不变的条件下,采用间断供电方式可取得与连续供电相同的结果;通过浅部已存在的离子晕,用电提取法可以发现深部隐伏矿体。  相似文献   

Relationship between Droplet pH and Aerosol Dissolution Kinetics: Effect of Incorporated Aerosol Particles on Droplet pH during Cloud Processing     

K. V. Desboeufs  R. Losno  J.L. Colin 《Journal of Atmospheric Chemistry》2003,46(2):159-172

The effect of incorporated aerosols on droplet pH was investigated by dissolution experiments on various particle types. These experiments conducted in an open-flow system show that the pH changes induced by aerosol solubilisation last up to 30 min, in the range of a typical droplet lifetime. These pH changes depend upon the initial pH of the experiment, i.e., the pH at cloud condensation. In the pH range between 3 and 5, the pH varies the most when it is high, since the base agents leached from the particles are neutralised by the protons present in the aqueous phase. A relationship between the neutralising capacity of the aerosol (NCA), i.e., the amount of uncompensated base species, and the pH after neutralisation has been found. Other experiments show that the NCA is related to the aerosol composition: silicates present more or less pronounced NCA, whereas C graphite presents a negative NCA, i.e., an acidifying capacity. The aerosol composition can be modified during cloud evapocondensation, notably by the addition of sulphate or sulphuric acid to the aerosol surface. NCA modification with cloud processing is observed when the amount of dissolved acid is larger than the neutralising capacity of the aerosol, i.e., when the droplet pH is less than a compensation pH characteristic of the aerosol type.  相似文献   

电提取离子法工作中的质量检查问题     

王文龙  肖力  杨秀华  马德锡  陈瑞林 《黄金地质》2003,9(1):52-55

电提取离子法在提取离子时是一个动态过程，提取量不但与提取时间有关，而且与指示电极的位置有关。检查工作量应布置在有电提取离子法异常的地段上，把质量检查和异常检查合并。第一、二次提取的异常明显存在，相对误差在20％以内，是矿致异常；第二次撮以量大于第一次几倍或更多，显示有隐伏金矿体存在；第二次提取量比第一次稍大，相对误差大于60％，提取量的数值小于或稍高于背景值，是背景区。2次测定结果的相对误差δ≤45％为合格，一个级。对四级质量的成果应扩大到20％的检查量，若质量仍达不到要求，应在检查量所代表的范围内返工。  相似文献   

VARIABILITY OF MELTWATER AND SOLUTE FLUXES FROM HOMOGENEOUS MELTING SNOW AT THE LABORATORY SCALE     

ROBERT F. HARRINGTON  ROGER C. BALES  PATRICK WAGNON 《水文研究》1996,10(7):945-953

Four experiments were performed to examine the relationship between the meltwater flow field and ion release from melting snow. A 0.4 m³ volume of snow was placed in a Plexiglass box and melted from above using a heating plate. The meltwater and solute fluxes issuing from the bottom of the snow were monitored. In experiments with NaCl tracer added to the snow, the solute concentrations were generally lower in the flow fingers than in the background wetting front. Dye tracer experiments revealed contemporaneous areas of concentrated dye and dilute meltwater in flow fingers. This suggests that the meltwater in flow fingers is diluted by low concentration water from the top of the snowpack. Flow fingers contribute more meltwater flux primarily because the flow is maintained for a longer period of time than in the non-finger areas; however, the relative contribution of flow fingers to solute flux was apparently not as great as that of the background wetting front because of dilution of solute in the flow finger areas.  相似文献   

4-硝基苯并-15-冠醚-5液液萃取分离锂同位素   总被引：1，自引：0，他引：1       下载免费PDF全文

王苏  贾永忠  王兴权  肖江  姚颖  张全友  景燕 《盐湖研究》2019,27(3):62-67

以4-硝基苯并-15-冠醚-5(4-NO_2-B15C5)做萃取剂,苯甲醚和1-丁基-3-甲基咪唑双(三氟甲烷磺酰)亚胺盐([C_4mim][NTf_2])作稀释剂和协萃剂,以1 mol/L LiCl溶液作萃取溶剂,构建高效的冠醚—离子液体/锂盐溶液的溶剂萃取体系。重点考察了有机相组成、冠醚浓度和锂盐阴离子等对锂同位素分离的影响。结果表明,4-硝基苯并-15-冠醚-5具有良好的锂同位素分离效果,在萃取CF_3COOLi时最大单级分离系数(α)可达1.043±0.01。  相似文献   

香港巨牡蛎对3种微藻的选择性摄食研究     

蓝文陆  付家想  杨斌  李天深  范航清  李琼珍  黄凌风 《海洋学报》2018,40(8):79-88

从微藻粒径大小、饵料密度以及营养价值角度,选取牟氏角毛藻（Chaetoceros muelleri）、亚心形扁藻（Platymonas subcordiformis）、球等鞭金藻（Isochrysis galbana）分别作为硅藻、绿藻和金藻的代表,开展了不同规格的香港巨牡蛎对3种微藻在同等密度、同等生物量混合条件下的摄食选择性研究。结果显示,香港巨牡蛎在两种不同混合藻条件下对3种不同微藻摄食选择性有显著性差异（P<0.01）。3种藻相同密度混合条件下,大、中、小3种规格香港巨牡蛎更倾向摄食粒径较大的亚心形扁藻,且贝类规格越大选择倾向性越低,摄食选择效率分别为0.32、0.35、0.48,对球等鞭金藻无明显选择性。3种藻等生物量混合条件下,香港巨牡蛎对亚心形扁藻和球等鞭金藻的摄食有选择性,且规格大小对选择效率影响显著（P<0.01）,个体越小选择性越强,小规格香港巨牡蛎倾向滤食亚心形扁藻（P<0.01）,大、中规格更倾向摄食粒径较小的球等鞭金藻。两种混合条件下,香港巨牡蛎都对牟氏角毛藻都有负的选择效率,而且牟氏角毛藻密度越高负值绝对值越大。微藻的细胞大小、形状、营养价值以及香港巨牡蛎的个体大小都对摄食选择性有着明显的影响,香港巨牡蛎的摄食选择性在现场海区中还明显受到生境及食物条件的限制。  相似文献   

Environmental Effects of Micro- and Ultra-microchannel Structures of Natural Minerals     

LU Anhuai HUANG Shanshan LIU Rui ZHAO Dongjun QIN Shan 《《地质学报》英文版》2006,80(2):161-169

The micro-channels usually refers to structural channels of minerals with aperture in the range of 0.3 nm to 2.0 nm. Such microchannels include, Mn-O octahedron channel filled by K in cryptomelane, and channel constructed by Si-O and AI-O tetragonal molecular sieve filled by Na and Ca in zeolite, and effectively have the function of molecular sieve. Here we point out that ultramicrochannels of natural minerals have apertures below 0.3 nm with the features of ionic sieves. The ultra-microchannels of mineral feldspar, accounting for half mass of the Earth＇s crust, have been largely ignored because the aperture is too small. In this work, we present that feldspar displays a certain degree of ion exchange and owns a feature of channel structure under both high and low temperatures. At high temperature, Na^＋ can enter the channels of feldspars. The content of Na2O in feldspar increases up to 15.9%. At middle temperature, Pb^2＋ can also enter the channels of feldspar as the result of ion exchange, leading thus to the formation of Pb-feldspar. At room temperature, about 97.94% Cd^2＋ can be removed and Cd-feldspar can be obtained. These phenomena indicate typical effects of ultra-microchannels of feldspar, which may be suggested as a potential for the treatment of heavy metal pollution and nuclear waste. The ultra-microchannels of natural minerals have played special role in migration and exchange of geomaterials. The molecular sieves of microchannels of a few natural minerals have the property of purifying molecular gas pollution. And the ionic sieves of ultramicrochannels of most natural minerals can purify ionic water contaminates.  相似文献   

中华哲水蚤对自然饵料的摄食选择性实验研究   总被引：3，自引：1，他引：2  

李超伦  孙松  王荣 《海洋与湖沼》2007,38(6):529-535

提要为了解自然环境中中华哲水蚤的摄食选择性及其生态策略,利用库尔特颗粒计数器测定了夏季黄海中华哲水蚤对自然水体中混合饵料的选择性摄食状况。调查期间,黄海海域季节性温跃层开始出现,水体中叶绿素a浓度为0.23—1.44mg/m3,最大值均出现在温跃层底部。水平分布上,水体中颗粒浓度近岸浅水区(A站:0.5—5.2×106μm3/ml)高于深水区(B站:0.3—0.7×106μm3/ml,C站:0.9—2.4×106μm3/ml);垂直分布上A、B站近底层颗粒浓度最高,C站颗粒浓度最高值出现在叶绿素a最大值区。中华哲水蚤对水体中粒径为1—100μm的食物颗粒均有摄食,但是颗粒大小和颗粒浓度对其摄食选择性均有一定的影响,主要摄食粒径为5—50μm的饵料颗粒。不同海域中华哲水蚤的个体摄食率分别为近岸A站23.82×106μm3/d、北部B站51.16×106μm3/d和南部C站36.32×106μm3/d,其日摄食量分别占体碳含量的2.1%(A站)、4.6%(B站)和3.2%(C站)。近岸海域(A站)中华哲水蚤摄食的饵料颗粒中各粒级组所占比例变化不大,但是深水区(B、C站)中华哲水蚤对于10—25μm范围内的饵料颗粒摄食选择性明显高于其它粒级组。中华哲水蚤的摄食选择性主要与水体中饵料的体积浓度相关,当饵料浓度降低时,中华哲水蚤可以通过扩大摄食饵料颗粒的粒径范围,增加对大颗粒的摄食以获得更多的营养。  相似文献   

拖网选择性对鱼类表型性状的选择作用研究     

梁振林  孙鹏  唐衍力  黄六一  鲁泉  刘长东  刘群 《海洋与湖沼》2008,39(5):488-493

参照渔业生物学、渔业资源解析学、数量遗传学等有关理论模型,并应用数值模拟方法,对长期选择性捕捞（重点为渔具选择性）是否参与造成了渔业资源的生物学变化（体长、性成熟等）进行某些基础性探索。设计了一个具有一定体长遗传特征的模拟鱼类种群,并利用一种具有固定选择性参数的拖网对其进行长期捕捞。结果表明,多年的持续的捕捞压力使得模拟种群中鱼类体长逐渐减小,减小的幅度随开发率的增大而增大,而终止捕捞后种群的体长并没有发生恢复的迹象,说明这种变化很可能伴随种群遗传的变化,具有自然不可逆性。  相似文献   

刺参对人工礁体设计关键指标的选择性   总被引：1，自引：0，他引：1  

林承刚  汝少国  杨红生  张立斌  刘石林  许强 《海洋科学》2012,36(3):13-21

采用平均聚集率(Mean Attractive Rate,MAR)作为统计分析指标,研究了仿刺参(Apostichopusjaponicas Selenka)对人工礁体结构设计关键指标(孔径、间隙、颜色、夹角)的选择性及其行为特性。结果表明:(1)随着实验时间延长,仿刺参在礁体模型上的聚集数量呈上升趋势;(2)礁体模型在自然光照条件下的聚参效果优于黑暗条件下的聚参效果(P<0.05);(3)孔径组各水平间聚参效果比较:2 cm>4 cm、16 cm>8 cm(P<0.05),4 cm与16 cm间差异不显著;间隙组各水平间聚参效果比较:2 cm>4 cm>6 cm>8 cm(P<0.05);颜色组各水平间聚参效果比较:黑色、蓝色、红色>绿色>白色>透明(P<0.05),黑色、蓝色、红色间差异不显著;夹角组各水平间聚参效果比较:15°>30°>45°、60°>90°、120°(P<0.05),45°与60°差异不显著,90°与120°差异不显著。说明仿刺参适应礁体模型需要一定时间,呈负趋光性。10 g至30 g的仿刺参,对设计指标为2 cm孔径、2 cm间距、深色、15°夹角的人工礁体,具有较好地选择性。  相似文献