An efficient method for evaluating the ground surface settlement of Hangzhou metro deep basement considering the excavation process

Acta Geotechnica - Based on the 16 collected well-documented excavation cases of the Hangzhou metro basement, the standard parameters of the basement, the standard excavation process, and the...     

Stable chlorine isotopic signatures and fractionation mechanism of groundwater in Anyang,China

The present work provides an online Bench II-IRMS technique for the measurement of stable chlorine isotope ratio, which is used to measure the δ³⁷Cl of 38 groundwater samples from the Karst and Quaternary aquifers in Anyang area. The regional distribution and signature of δ³⁷Cl value are characterized on the base of isotopic data. The results suggest that the δ³⁷Cl value of Quaternary groundwater decreases with increasing Cl^? concentration, and has no correlation with δ¹⁸O and δD values, but closely correlates with the depth to water table. The fractionation mechanism of the chlorine isotope is expounded according to the type of groundwater. The δ³⁷Cl value of karst water is generally positive, which is relevant to the dissolution of evaporite (gypsum mine), and may be caused by the mixing of groundwater and precipitation. The groundwater of Quaternary unconfined aquifer is mainly recharged by precipitation, and the δ³⁷Cl value of groundwater is generally negative. The δ³⁷Cl value of groundwater in Quaternary confined aquifer is more negative with increasing the depth to water level and elevated Cl^? concentration, which is possible to result from the isotope fractionation of ion filtration. The groundwater with inorganic pollutants in Quaternary unconfined aquifer has generally a positive δ³⁷Cl value.     

Spatial and temporal evolution characteristics and causes of drought and flood in the Henan section of the Yellow River

Natural Hazards - Under the background of global warming, it is very important to explore the spatial–temporal evolution and causes of regional drought/flood for the realization of drought...     

2013-2016年惠州市大气颗粒物质量浓度变化特征和典型污染过程分析

利用2013-2016年惠州市5个环保国控站的PM质量浓度和国家基本气象观测站的气象要素观测数据及NCEP/NCAR日平均再分析资料,统计分析了惠州市大气颗粒物质量浓度变化特征及其与气象条件的关系。结果表明：2013-2016年惠州市大气颗粒物质量浓度、污染日数和超标日数均呈明显下降趋势,2016年PM10年平均质量浓度已接近年平均质量浓度限值一级标准,PM2.5年平均质量浓度达到年平均质量浓度限值二级标准。大气颗粒物质量浓度冬季的最高、秋季的次之,非汛期的（10月次年3月）显著高于汛期的（4-9月）。PM2.5污染日均出现在非汛期,尤其是冬季的1和12月,大多出现在晴朗干燥的东北风天气下。分析惠州市20132016年间两次长时间大气颗粒物污染过程发现,这两次大气颗粒物污染过程出现在冷空气减弱、冷高压东移出海后或下一波冷空气来临前,但随着南下冷空气的到来,北风加大或带来明显降水,空气质量明显好转。     

一种动态绘制无交叉法线坡面线的新算法

研究一种动态绘制任何形状的无交叉法线坡面线的新算法,用以克服传统手工绘制复杂坡面线及原有自动化技术的不足。并证明基于＂实交点定理＂及其＂补充定理＂的算法是生成无交叉坡面线的充分条件。进一步说明使用该算法可以动态绘制地形图所需要的任何形状的法线自然（加固）斜坡、崩崖、陡崖、陡石山、堤岸等图式符号。最后,通过三组试验验证算法的有效性,分析算法的特点及影响因素。     

自动站数据维护和异常处理之浅析

介绍了自动气象站地面数据的维护及自动站运行过程中较常出现的数据异常等应注意的问题和相应的处理方法。     

Organochlorine pesticides in sediments of Laizhou Bay and its adjacent rivers, North China

Organochlorine pesticides (HCHs, DDTs and HCB) have been investigated in sediments of Laizhou Bay and its adjacent rivers. The average concentrations of HCHs, DDTs and HCBs are 0.09 ng/g dw, 0.59 and 0.05 for marine sediments and 0.55, 8.6 and 1.1 for riverine sediments, respectively. Laizhou Bay is less contaminated by HCHs and DDTs in comparison with other coastal regions around the world, including the other two biggest bays in Bohai Sea. Fresh input of lindane and dicofol-type DDT were found in several riverine sites. Relatively strong TOC-dependence of HCB distribution in the entire studied area suggested no point source existed and/or water-sediment equilibrium achieved. No significant difference of α/γ-HCH ratios have been observed between marine and riverine sediments. However, o,p′-DDT/p,p′-DDT ratios varied largely between the two regions.     

总部经济视角下港口城市转型发展的规律与启示

世界港口城市发展演变规律表明,在不同历史时期,港口城市发展与演变均体现了总部经济实质:港口城市以先天区位优势成为吸引代表先进生产力发展水平的高级要素聚集高地,形成了以集聚性、扩延性、示范性、辐射性和吸引性为特点的先进经济形态,并最终演变成现代总部经济形态。世界先进港口城市的转型与发展给我们以下启示:现代总部经济发展必须以发达的交通集疏网络为前提;以高水平的信息化建设为重点;以高素质的人力资源为依托;以优越的法制环境为保障;以完善的专业化服务体系为支撑。     

华南准静止锋暖区内降水的物理化学特征

介绍了一次华南准静止暖区内降水的物理化学特征的综合观测分析结果。主要有：①暖区内积云降水雨滴浓度不高，但滴径较大，谱型以多峰谱为主；②雨水ｐＨ值较低，平均４．４３，离子成分中ＮＯ３，Ｃｌ，ＳＯ４，ＮＨ＾＋４，Ｎａ＾＋的浓度较高；③本次降水清除了气溶胶总质量的４５％，对Ｃｌ，Ｆ，ＮＯ３的清除率较高；④由于气溶胶中阴离子被雨水清除的效率较高（主要是ＮＯ３）而阳离子的清除率低，致使雨水ｐＨ值下降，这可能