Dynamics of the eco-environmental quality in response to land use changes in rapidly urbanizing areas: A case study of Wuhan,China from 2000 to 2018

Journal of Geographical Sciences - The dramatic land use changes that occur in rapidly urbanized areas are important inducement to changes in the eco-environmental quality. Investigating urban land...     

Ab initio prediction of 29Si-NMR chemical shifts

The ability of several ab initio models to predict experimental ²⁹Si-NMR chemical shift is examined. The shielding values of trimethylsilyl chloride (A), t-butyldimethylsilyl chloride (B) and allytrimethylsilane (C) are calculated by GIAO, CSGT and IGAIM methods, using HF/6–31G^*, B3LYP/6-31G^*, HF/6–311+G^**, B3LYP/6–311+G^** and MPW1PW91/6–311+G^** models respectively. The ²⁹Si chemical shifts calculated by GIAO method using HF/6–311+G^** model are highly in agreement with those obtained experimentally. All of the models above reproduce the trends of chemical shifts in all cases studied, suggesting that the models are of practical value.     

灵台-阿木去乎剖面地壳速度结构

在Ⅰ测线观测资料的基础上,本文结合测区特点给出了高程校正及沉积层校正方法,利用反射波与莫霍面折射波运动学特性进行一维、二维地壳结构的正、反演计算,获得了自甘肃夏河至灵台460公里范围内的分层地壳结构,认为西部地壳厚度约51公里,东部仅为44公里,已属鄂尔多斯地台区结构,与地槽区的分界线大致对应地表陇县固关镇。武山与张家川之间在15-20公里深处存在低速层。结合地震波的动力学特性,可判定本测线通过的超壳断层有鄂尔多斯西缘-六盘山断裂、西秦岭北缘断裂和武山南北向断裂。     

模拟CO_2埋藏的煤储层元素迁移实验研究

采用高压超临界CO2地球化学反应器对CO2在煤储层中的地质埋藏进行模拟,利用电感耦合等离子体发射光谱仪(ICP-OES)以及电感耦合等离子体质谱(ICP-MS)分别对淋滤液和煤样中的10种微量元素进行测试,对煤中微量元素在CO2的地质埋藏过程中的迁移进行了实验研究。结果表明:在CO2的地质埋藏过程中对煤的有机组成和无机矿物等均具有改造作用,从而影响到煤中微量元素的赋存和迁移特征,Cr、Zn、Cu等元素迁移能力相对较强,而Co、Ba、V等元素相对较弱;元素迁移能力大小顺序为:CrZnCuNiCdMnCoBaV。     

Investigation on strength and stability of jointed rock mass using three‐dimensional numerical manifold method

This paper proposes a numerical model for jointed rock masses within the 3‐D numerical manifold method (NMM) framework equipped with a customized contact algorithm. The strength of rock sample containing a few sets of discontinuities is first investigated. The results of models with simple geometries are compared with the available analytical solutions to verify the developed computer code, whereas models with complex geometries are simulated to better understand the fundamental behavior and failure mechanism of jointed rock mass. Furthermore, the stability of jointed rock mass in an underground excavation is studied, where rock failure process is determined by the 3‐D NMM simulation. The simulation results provide valuable guidance on excavation process design and stabilization design in rock engineering practice. Copyright © 2012 John Wiley & Sons, Ltd.     

使用DOS批处理文件备份自动气象站数据

从备份自动站数据文件的实际需要出发,通过实例由浅及深地介绍了用DOS批处理文件多目的地、多方式备份自动站数据的方法,包括本机备份、备份到局域网、备份到网络服务器以及自动备份等。     

青藏高原晚始新世干旱化事件：改则盆地康托组碳酸盐岩碳氧同位素的记录

改则盆地位于青藏高原腹地,盆地内沉积物记录了高原古环境变化的重要信息。本文对改则盆地康托组碳酸盐岩碳氧同位素进行研究,结果显示改则盆地中-晚始新世的演化分为两个阶段:1中始新世湿润气候下开放湖盆阶段:虽然碳酸盐岩δ~(18)O值在43层处向正值偏移,但整体~(18)O和~(13)C强烈亏损,并且该时期碳酸盐岩δ~(18)O值和δ~(13)C变化相关系数为R~2=0.082。表明该阶段的研究区虽然经历过短期蒸发作用增强或补给水减少,但整体是气候湿润条件下补给水丰富的开放型湖盆。2晚始新世干旱气候下封闭湖盆阶段:经过中新世晚期(63层)气候和湖泊水文状态的过渡,晚始新世~(18)O和~(13)C同位素富集,δ~(18)O值和δ~(13)C值变化相关系数为R~2=0.7762。表明该阶段气候干旱,蒸发作用强烈,湖盆萎缩成为封闭湖盆。综合前人研究,认为青藏高原腹地及北缘、东北缘在晚始新世存在明显的区域性干旱化事件。对比分析青藏高原隆升、全球气候记录、全球海水Sr和大气CO_2记录,认为青藏高原腹地和北部的干旱化事件主要受青藏高原隆升的影响。     

地下水弥散系数的测定

以大红染料为示踪剂,采用单井脉冲注入示踪剂的方法测定了主井和观测井中示踪剂的浓度变化,并用解析公式法计算了西小洞垃圾场地下水的纵向弥散系数。     

青黄公路交通调查及交通量预测

通过对1998年2月青黄公路的交通调查,分析了青黄公路的交通现状,根据青岛市的国民经济增长速度、交通运输发展及城市出入口资料,利用弹性系数法预测了2000年和2010年青黄公路的城市交通量。