蒙脱石降氟作用的实验研究

实验表明蒙脱石吸附氟的能力与溶液的PH值呈显著的负相关关系：在较低PH值条件下，蒙脱石的吸氟量较大，具有显著的降氟作用；而对中性—碱性溶液来说，蒙脱石对氟的吸附能力则大大降低，基本不具吸氟能力。蒙脱石的吸氟量还与其用量及含氟溶液的浓度有关。吸附原因一方面是由于体系PH值降低，导致其表面带正电荷而吸附F^-；另一方面，随着NaF浓度升高，蒙脱石的双电层变薄，体系ξ电势减少，发生絮凝作用，并携带F^-沉淀下来。另外，F^-与OH^-的离子交换作用也是酸性条件下蒙脱石吸氟的一个重要原因。     

Driving environmental certification: its impact on the furniture and timber products value chain in South Africa

In this new globalised era there is an increasing demand in the developed world for environmental certification (Forestry Stewardship Council) of furniture and timber products. The imposition of this requirement has major implications for producers in developing countries. This paper examines this issue from a value chain perspective, exploring how certification requirements are driven through the links of the global furniture value chain. It does so by focusing on the dynamic underlying the spread of FSC certification through the furniture and timber industry in South Africa, and investigates the role of the various organisational ‘drivers’ of the system. In doing so it explores how developing country firms relate to these opportunities and pressures, drawing out the logistical implications, the costs and benefits, as well as the future for FSC certification. It concludes with a discussion of the role of buyers, agents, certification agencies and manufacturers in driving FSC certification through the wood products value chain in South Africa.     

元素提取器周围土壤的pH值变化

电提取过程依赖直流电场的作用,直流电场持续作用导致土壤介质pH值的变化,当这种变化达到一定程度,又将对电提取过程产生不利影响。因此,它们之间相互关系的研究是电提取方法应该面对的课题。本文通过实际试验数据,揭示和反映了电提取过程中元素提取器周围土壤pH值变化的强度和范围,为上述问题研究提供了初步资料依据。     

HYDROGEN ION CONCENTRATION IN RAIN WATER

Continuous measurements of pH precipitation falling from cumulus clouds in semi-arid region(Colorado,USA),and in wet temperate zone(Bologna,Italy)were made.In Colorado the pHwas constant at 7.3 for a period of time,and later changed to 7.0 and remained constant at thisvalue during the remainder of the storm.In Italy the pH fluctuated continuously between theapproximate values of 5.7 and 6.4 during the storm.The changes in hydrogen ion concentrationreflect the chemical composition of cloud condensation nuclei and of scavenged aerosol particles andgases presented in the region.     

Fractionation of dissolved organic matter affected by polyvalent metal cations

The purpose of the study was to evaluate the influence of polyvalent cations known to form complexes with natural organic substances on the operational fractionation of dissolved organic matter (DOM) using XAD-8 adsorber resin. Dissolved organic matter solutions from a forest floor were treated with increasing concentrations of polyvalent metal cations (Ca²⁺, Al³⁺, Fe³⁺) at different pH levels. Then the concentrations of total dissolved organic carbon (DOC) and the distribution between hydrophilic and hydrophobic DOC were determined. The concentrations of total DOC decreased slightly when the C/metal ratio was less than 10, especially for Al and Fe. Hydrophilic DOC increased and hydrophobic DOC decreased with increasing concentrations of metal cations. Effects increased in the order Ca<Al<Fe and were more pronounced at low DOC concentrations and high pH values. The reason for the reduction of the DOC concentrations seemed to be the formation of insoluble metal–DOM complexes, while soluble metal–DOM complexes may induce an alteration of the distribution between hydrophilic and hydrophobic DOC. Thus, the polyvalent cations and their concentration need to be considered when DOM fraction distributions, determined with XAD-8 resin, of different waters are compared, especially at low DOC contents and high pH.     

水岩体系Eh-pH法及其在砂岩型铀矿体定位研究中的应用——以新疆伊犁盆地512铀矿床为例

512铀矿床不同氧化还原环境水岩体系Eh和pH值的研究结果表明：同一氧化还原环境的水岩体系Eh平均值极为接近；不同氧化还原环境的水岩体系Eh值差异明显，即从氧化带到还原带，水岩体系Eh值明显下降；不同氧化还原环境，其水岩体系pH值也有所不同，氧化带和还原带处于弱碱性介质环境，过渡带（矿化地段）处于中性介质环境；水岩体系Eh和pH值可以作为划分含矿层氧化还原环境分带及圈定铀矿体位置的依据。     

云南省MS≥6.0地震序列的基本特征

选取了云南省 196 5— 2 0 0 0年的 19个 MS≥ 6 .0地震序列 ,利用震后 30天的余震资料 ,分析了各地震序列的震级结构。运用古登堡—里克特关系式及大森—宇津公式分别计算了各余震序列的 b值和 p值。结果表明 ,云南省每一次 7级或 6级地震发生后 ,均有大量余震发生 ,但余震活动的强度和频度在各序列之间存在较大差异 ,其原因可能与震源区的介质、构造差异有关。计算得到的 b值为0 .38— 0 .70 ,b值的大小体现出了一定的区域特征 ;p值大多接近或大于 1.0 ,但看不出区域特征。在主震—余震型和双主震—余震型地震序列之间 ,b值、p值看不出显著差异     

陕西柞水银硐子银铅矿床成矿物理化学条件研究

在地质-地球化学研究的基础上,本文运用热力学原理研究成矿作用的物理化学条件。通过矿物包裹位测温、测盐度研究,应用闪锌矿压力计,运用热力学计算,获得两个成矿阶段的成矿温度、成矿压力、成矿的pH、Eh,以及硫逸度和氧逸度,成矿溶液的盐度。认为导致成矿金属元素沉淀富集成矿的因素是含矿流体加入了还原硫及pH的升高,成矿过程总体是在比较还原的条件下进行的。     

2017年南京酸雨特征及连续发生的成因分析

利用南京市1992—2017年逐日酸雨监测数据、2017年大气污染物浓度和探空资料,研究了2017年连续酸雨出现特征及成因。结果表明:2017年南京酸雨发生频率38%,为近5 a来最低;年降水pH值为4.92,大于2014年,小于2015年和2016年;秋季酸雨发生频率最高、酸度最强,春季次之,夏季酸雨污染最轻;全年共出现了4次连续酸雨过程,高空多短波槽活动和低空切变的长时间维持为连续酸雨的产生提供了有利的环境背景,局地污染源、受低层风引导的外来污染物以及“假日效应”的叠加影响共同造成南京强酸雨的出现;此外,由于大气中水汽和能量的季节差异,也造成每次过程在降水强度、降水pH值上有所不同。     

吉林省大黑山条垒南段构造演化与成矿作用

作者将本区的构造演化划分成三个阶段，即海西－印支期、燕山期和四川期。海西－印支期应力作用以近ＳＮ向挤压为主，成矿作用为Ｐｂ－Ｚｎ－Ｃｕ多金属硫化物矿床；燕山期应力作用以ＮＷ－ＳＥ向挤压为主，成矿作用为Ｐｂ－Ｚｎ－Ａｇ为主，平均差应力值１２０．５ＭＰａ；四川期应力作用呈ＮＮＥ－ＳＳＷ向，成矿作用以Ａｇ－Ａｕ为主，平均差应力值１０１．４ＭＰａ。