黏弹性地基中PCC桩扭转振动响应解析方法研究

考虑土体材料的黏性阻尼和桩-土扭转耦合振动,把桩看作一维杆,将土体视作三维轴对称黏弹性介质,对黏弹性地基中现浇混凝土大直径管桩（简称PCC桩）扭转振动频域特性进行了理论研究,采用Laplace变换和分离变量的方法求得了桩顶扭转频域响应解析解。将所得解完全退化到实心桩的解,并与经典平面应变解进行对比,验证了解析解的合理性。分析了桩长以及土体黏性阻尼系数对桩顶速度导纳和复动刚度的影响,得到了各参数对桩扭转振动特性影响的规律。分析表明：桩周土黏性阻尼系数增大可以显著提高桩顶扭转复动刚度和减小速度导纳振荡幅值,而桩芯土黏性阻尼系数的影响不明显;桩长越长,桩顶复动刚度越大,速度导纳振荡幅值越小,但当桩长增大到一定程度时,再继续增加桩长,桩顶复动刚度基本没有改变。     

超道相干体技术在复杂断块断裂解释中的应用

针对复杂断块的断裂地震特征,笔者利用超道构建技术,并与基于小波变换的相干技术集成,再进行相干计算。超道构建技术具有不改变地层的原有信息而保留了地层的倾角特征、降低属性分析的平均效应的优势,试算结果证明,该方法不仅计算速度快,而且抑制噪声能力强。通过与传统相干算法实际应用对比,该算法有效地突出了地层的高连续性特征,提高了识别断层的分辨率,地质特征信息丰富,有利于断层解释,尤其适用于低信噪比地震资料地区。     

石墨炉原子吸收光谱法测定地质样品中微量银

样品经盐酸-硝酸分解处理,以硫酸铵为基体改进剂,石墨炉原子吸收光谱法测定地质样品中微量的银.结果表明该方法简便、快速、准确,相对标准偏差（RSD,n=6）为1.89％～6.70％,加标回收率为94％～106％.     

全球原油贸易网络视角下的亚洲溢价与中日印韩原油潜在竞争关系

随着全球原油贸易关系的复杂化和亚洲原油需求的上升,全球能源市场的“亚洲溢价”现象成为需要关注的议题。本文基于全球石油贸易网络复杂性视角,选取1993—2018年国际原油贸易数据进行样本数据考察,通过构建复杂网络模型和潜在竞争指数,对全球原油贸易网络中的亚洲溢价现象和中日印韩四国潜在竞争力进行分析。结果表明：全球原油贸易集团分化交融,中日印韩呈现出贸易集团化的趋势。从全球原油贸易网络指标来看,中日印韩四国在全球原油贸易网络地位和影响力不断提升,有力推动了全球原油消费中心向亚太地区转移。潜在竞争指数表明,中国与日本、印度、韩国的潜在原油竞争关系呈现出不同特征,中日表现出“先强后弱”的特点,而中印、中韩表现为整体持续增强的特征。     

南极乔治王岛晚白垩世地幔源火山岩Nd、Sr同位素和微量元素证据

对乔治王岛上白垩统半三角组火山岩样品进行了 Rb- Sr同位素等时线年龄测定 ,所获结果为 71 .3 3± 0 .3 Ma。通过 εND(T) - 14 7Sm/14 4Nd,14 3 Nd/14 4Nd- 87Sr/86 Sr,87Sr/86 Sr- Sr和 87Sr/86 Sr- K2 O/(K2 O+Na2 O)的相关性研究表明 ,该火山岩物质主要来自亏损地幔 (DMM)源区 ,基本上未受到地壳物质混染。其中 6个样品的平均 Sm- Nd模式年龄 (TNd DM)为 443 .3± 2 0 .6 Ma,可能反映了在研究地区的岩浆源区化学分异事件的时代。微量元素的特点表明 ,半三角组样品属典型的钙碱性火山岩系列 ,与长城站地区第三系火山岩相类似 ,同属于岛弧火山活动的产物。     

Complex multiple cosmogenic nuclide concentration and histories in the arid Rio Lluta catchment,northern Chile

Terrestrial cosmogenic nuclide (TCN) concentrations measured in river sediments can be used to estimate catchment‐wide denudation rates. By investigating multiple TCN the steadiness of sediment generation, transport and depositional processes can be tested. Measurements of ¹⁰Be, ²¹Ne and ²⁶Al from the hyper‐ to semi‐arid Rio Lluta catchment, northern Chile, yield average single denudation rates ranging from 12 to 75 m Myr^–1 throughout the catchment. Paired nuclide analysis reveals complex exposure histories for most of the samples and thus the single nuclide estimates do not exclusively represent catchment‐wide denudation rates. The lower range of single nuclide denudation rates (12–17 m Myr^–1), established with the noble gas ²¹Ne, is in accordance with palaeodenudation rates derived from ²¹Ne/¹⁰Be and ²⁶Al/¹⁰Be ratio analysis. Since this denudation rate range is measured throughout the system, it is suggested that a headwater signal is transported downstream but modulated by a complex admixture of sediment that has been stored and buried at proximal hillslope or terrace deposits, which are released during high discharge events. That is best evidenced by the stable nuclide ²¹Ne, which preserves the nuclide concentration even during storage intervals. The catchment‐wide single ²¹Ne denudation rates and the palaeodenuation rates contrast with previous TCN‐derived erosion rates from bedrock exposures at hillslope interfluves by being at least one order of magnitude higher, especially in the lower river course. These results support earlier studies that identified a coupling of erosional processes in the Western Cordillera contrasting with decoupled processes in the Western Escarpment and in the Coastal Cordillera. Copyright © 2008 John Wiley & Sons, Ltd.     

石墨炉原子吸收法测定地球化学样品中痕量银

本文采用石墨炉原子吸收光谱法测定地球化学样品中痕量银。选择硝酸镁和硫脲混合溶液为基体改进剂,银的灰化温度为800℃,研究了最佳的分析测定条件。该方法检出限为0．01μg／g。用该方法对国家地球化学标准样品的测定结果与标准值相符。     

Major and trace element geochemistry of neutral and acidic thermal springs at El Chichón volcano,Mexico: Implications for monitoring of the volcanic activity

Four groups of thermal springs with temperatures from 50 to 80 °C are located on the S–SW–W slopes of El Chichón volcano, a composite dome-tephra edifice, which exploded in 1982 with a 1 km wide, 160 m deep crater left. Very dynamic thermal activity inside the crater (variations in chemistry and migration of pools and fumaroles, drastic changes in the crater lake volume and chemistry) contrasts with the stable behavior of the flank hot springs during the time of observations (1974–2005). All known groups of hot springs are located on the contact of the basement and volcanic edifice, and only on the W–SW–S slopes of the volcano at almost same elevations 600–650 m asl and less than 3 km of direct distance from the crater. Three groups of near-neutral (pH ≈ 6) springs at SW–S slopes have the total thermal water outflow rate higher than 300 l/s and are similar in composition. The fourth and farthest group on the western slope discharges acidic (pH ≈ 2) saline (10 g/kg of Cl) water with a much lower outflow rate (< 10 l/s).