Analytical solutions for organic contaminant diffusion in triple-layer composite liner system considering the effect of degradation

Acta Geotechnica - This paper presents analytical solutions for predicting one-dimensional diffusion of an organic contaminant through a triple-layer composite liner system comprising a geomembrane...     

A re-assessment of nickel-doping method in iron isotope analysis on rock samples using multi-collector inductively coupled plasma mass spectrometry

Element doping has been proved to be a useful method to correct for the mass bias fractionation when analyzing iron isotope compositions. We present a systematic re-assessment on how the doped nickel may affect the iron isotope analysis in this study by carrying out several experiments. We find three important factors that can affect the analytical results, including the Ni:Fe ratio in the analyte solutions, the match of the Ni:Fe ratio between the unknown sample and standard solutions, and the match of the Fe concentration between the sample and standard solutions. Thus, caution is required when adding Ni to the analyte Fe solutions before analysis. Using our method, the δ⁵⁶Fe and δ⁵⁷Fe values of the USGS standards W-2a, BHVO-2, BCR-2, AGV-2 and GSP-2 are consistent with the recommended literature values, and the long-term (one year) external reproducibility is better than 0.03 and 0.05‰ (2SD) for δ⁵⁶Fe and δ⁵⁷Fe, respectively. Therefore, the analytical method established in our laboratory is a method of choice for high quantity Fe isotope data in geological materials.

     

基于OMI数据的贵州省对流层NO2浓度时空变化分析

利用OMI卫星遥感数据提供的NO2浓度产品及气象站点数据,分析了2005-2017年贵州省对流层NO2柱浓度时空分布特征及其影响因素。结果表明:①贵州省NO2柱浓度年均值较小,说明贵州省空气质量整体比较好,年变化为NO2柱浓度先升高再降低的趋势,冬季最高、夏季最低,而月变化呈内凹型分布,一年中最大值大多出现在1月,7月出现最低值的次数最多;②空间分布呈西高东低、北高南低的特点;③在9个地市州中,六盘水市的NO2柱浓度年均值最大,贵阳市位于第二,浓度最低的是黔东南州。④降水和温度对NO2柱浓度都具有一定的负影响。     

Unusual hydrocarbon waxes detected in <Emphasis Type="Italic">Salix oritrepha</Emphasis> leaf from Nianbaoyeze Mountains,eastern Qinghai-Tibetan Plateau

Plant biomarkers, such as hydrocarbon waxes, are frequently found in various sediments and could be adopted as paleovegetation and paleoclimate indicators. Nevertheless, scarce researches have focused on leaf waxes in higher plants of alpine region. Herein, hydrocarbon leaf wax components of Salix oritrepha, which flourish in Nianbaoyeze Mountains in eastern Tibetan Plateau were fully discussed. The n-alkane distribution in leaves ranges from n-C₂₁ to n-C₂₉ with maxima at n-C₂₅, which were entirely different with Salix taxa displayed in previous surveys in non-alpine regions. The unusual even carbon nalkenes from n-C_22:1 to n-C_30:1, which were thought to appear only in aquatic organisms, were firstly reported in an alpine plant. Additionally, iso-(2-methyl) alkanes, ranging from i-C₂₃ to i-C₂₉ with maxima at i-C₂₅, which have been commonly reported in microorganisms, were also identified in an alpine plant for the first time. Unusual hydrocarbon distribution detected in Salix oritrepha leaf from Nianbaoyeze Mountains is most likely due to the extreme environment in such alpine region.     

半潜平台总体强度评估的谱分析法和设计波法对比

采用谱分析方法对半潜平台进行总体强度评估,验证了谱分析方法的可操作性。利用谱分析法计算平台关键连接部位处的应力水平,并与采用设计波法得到的应力结果进行比较,讨论两种方法之间的相关性。计算表明,谱分析法与设计波法存在一定的相关性,谱分析法的计算结果相对准确可靠,设计波法的计算精度依赖于选取的特征载荷工况,且目前规范推荐的载荷工况不够全面。本研究成果可为类似平台的总体强度分析提供参考。     

Enhancement of scale-free network attack tolerance

Despite the large size of most communication and transportation systems, there are short paths between nodes in these networks which guarantee the efficient information, data and passenger delivery; furthermore these networks have a surprising tolerance under random errors thanks to their inherent scale-free topology. However, their scale-free topology also makes them fragile under intentional attacks, leaving us a challenge on how to improve the network robustness against intentional attacks without losing their strong tolerance under random errors and high message and passenger delivering capacity. Here we propose two methods (SL method and SH method) to enhance scale-free network's tolerance under attack in different conditions.     

几种固沙植物的水分关系

本文研究对象是甘肃省河西走廊中部地区几种固沙植物和地带性旱生植物。在测定其水势、束缚水含量、自由水含量、蒸腾强度和持水力等生态生理指标的基础上分析讨论了各个植物种水分关系的特点和适应干旱环境的方式。     

胶东棉花洲金矿地质特征及找矿方向

棉花洲矿区位于胶东隆起带,昆嵛山复背斜与ＮＥ,ＮＮＥ向断裂构造的复合部位。ＮＮＥ向左行压扭性断裂是主要控矿构造,已发现金矿脉８条。赋矿围岩为鹊山中粗黑云母花岗岩,金与黄铁绢英岩蚀变关系密切,为中低温热液多金属硫化物石英脉型金矿床,成矿温度为１６０￣３７０℃,可划分为４个成矿阶段;黄铁矿－石英;金－黄铁矿－石英;金－多金属硫化物－石英;石英－碳酸盐。根据找矿标志确定有利的成矿部位是已知矿脉（体）的深     

我国煤矿采区高分辨率地震勘探的成果

针对以往新建矿井因地质构造不清所造成的巨大经济损失的现实情况,1 991年以来,国家发展银行及国家能源投资公司投入资金开展了大规模矿井采区地震勘探工作,取得了很大成就。本文介绍了几年来采区地震勘探所取得的成果、所产生的经济效益,对所能解决的地质问题也作了重点介绍,并对所存在的问题及发展方向提出了看法。      

纤维水镁石在无机铵盐中的溶解行为研究

纤维水镁石在水中可放出自由基,其在酸性环境中呈现化学活性,在体液环境中有细胞毒性。在水体环境中,它与一切释放出铵离子的物质反应并使自身发生溶解,其机理是可溶性铵盐在溶液中可离解出铵离子并放出质子,而水镁石在水中可电离出羟基。二价铁的存在使氧化还原反应常常伴生,最终形成三价铁铵盐复盐。因此,人体内的可溶性铵盐和体液中存在的铵离子可与水镁石粉尘作用并使之部分溶解。粒度增大和温度升高有利于镁元素在平衡体