澜沧江中下游泥沙微表面电荷特性与磷吸附关系研究

河流泥沙是水生态系统生源要素的重要附着载体,其微形貌及电荷特性直接关系着泥沙对溶解态营养盐或污染物的吸附能力。本研究选取澜沧江中下游干流及主要支流为考察对象,采集28个河流水库断面的悬移质泥沙,采用原子力显微镜测定泥沙微表面电荷量,探究澜沧江泥沙的微表面电荷性质,研究纳米尺度下泥沙的微表面特性。研究结果表明:(1)微观界面,形貌对表面电荷分布影响明显,在纳米尺度下电势图与相位差图均展现出明显非均匀分布特征;(2)在流域分布上,不同区域表面电荷存在较大差异,流域沿程变化对泥沙表面电荷产生重要影响,总体变化呈现先减小后增大的趋势,表面电势值变化范围为-201.47～35.34 mV,表面电荷密度范围为0.07～3.65 mC/m²,不同区域电荷特性差别明显;(3)在梯级水电筑坝影响下,坝上坝下泥沙颗粒电势差与水库库容存在较好的线性相关关系,相关系数为0.8214,且坝下电势普遍高于坝上区域;(4)泥沙表面电势与磷吸附之间具有较强相关性,其相关系数为0.6657,同时表现出较好的线性拟合关系。研究结论对深入理解水电大坝建设对流域内污染物的迁移转化及解释泥沙的表面电性特征...     

元谋地区超基性岩浆型铂钯矿成矿作用探讨

川滇新裂谷作用伴有强烈的岩浆活动,除大量玄武质岩浆喷溢外,在元谋朱布、黑泥坡等地见超基性岩体侵入,赋存有铂钯矿床.文章通过分析黑泥坡、朱布超基性岩体的土壤地球化学特征和岩石地球化学特征,结合元谋地区地质特征,提出了元谋地区超基性岩体铂钯矿床的成矿模式.     

Morphological and sedimentary features of sandy-muddy transitional beaches in estuaries and bays along mesotidal to macrotidal coasts

Sandy-muddy transitional beaches (SMT-Beaches), representing the transition from sandy beaches to tidal mudflats, should theoretically develop very different morphological and sedimentological characteristics in river estuaries and in semi-enclosed bays due to their contrasting dynamic sedimentary environments. Evidence, however, is rare in the scientific literature. To reveal these morphological and sedimentary differences, the sand–mud transition (SMT) boundary distribution, beach profiles, and surface and downcore sediment grain-size compositions of 27 SMT-Beaches located along mesotidal to macrotidal coasts of the western Taiwan Strait, southeastern China, were investigated. The results show that typical estuarine SMT-Beaches are mainly characterized by an ambiguous SMT, a long distance between the SMT and the coastline (31–302 m), lower SMT and inflection point altitudes (average –0.76 m and –0.04 m), and lower upper beach gradients (~0.068) with fine sand. Estuarine SMT-Beach sediments display clear interbedded mud and sand layers, implying potential SMT migrations over various timescales. By contrast, typical bay SMT-Beaches are characterized by distinct SMT, a short distance between the SMT and the coastline (11–52 m), higher SMT and inflection point altitudes (~0.24 m and ~0.35 m), and narrower upper beaches with higher gradients (~0.095) and coarse sand. Bay SMT-Beaches present relatively stable sedimentary sequences and a narrow gravel belt surrounding the inflection point and/or SMT. These morphological and sedimentary differences between the two SMT-Beach types are initially constrained by sediment supply and transport and are further affected by tide conditions and wave climate. Sediment supply and transport predominately control the sediment structures, while the tidal range strongly influences spatial variations in SMT distances. Wave climate normally drives SMT altitude variations. This study highlights the morphological and sedimentary differences in SMT-Beaches in estuaries and bays, providing important knowledge for further revealing their morphodynamic processes and potential future nourishment. © 2020 John Wiley & Sons, Ltd.     

基于表层岩土渗透对三峡井网井水位降雨影响的精准分析

为研究三峡井网表层岩土渗透对井水位降雨的影响,采取井区表层岩土垂向渗透性测试方法试验,测得表层岩土垂向渗透性,并建立数学模型,用于降雨渗入补给分析。在此模型基础上,通过三峡井网8口井水位、气象三要素的对比观测资料对井水位日动态、月动态、年动态的影响进行精准分析与验证。结果表明:这种影响的特征是相当复杂的,同一个降雨过程在不同井上产生的影响特征不同,这一方面可能与各井的水文地质条件不同有关,另一方面可能还与各井点的降雨过程的差异也有关。     

强震变形的地震大地测量监测与研究

地震大地测量是将大地测量（特别是空间大地测量）与地震学及构造地质学进行融合的新兴交叉学科,其可用于监测地震孕育的地球物理背景场及动态变化过程,对相关形变实现了10²a～10^-2s的宽频带监测,基本弥补了地震学与构造地质学间的频率空白。以多频带的地震大地测量技术（GNSS、InSAR、高频GNSS）为支撑的陆态网络工程,不仅获得了中国大陆长期的地壳运动图像,而且在强震形变监测中发挥了重要作用。汶川、芦山、尼泊尔廓尔喀及九寨沟等地震的研究成果表明,高频/静态GNSS、InSAR、精密水准相融合的多频大地测量,极大地拓展了地震形变监测的时空频域,促进了大陆型地震的相关研究,为地震预测预警研究奠定了基础。然而,目前使用的地震大地测量资料有限,同时,我国地震大地测量监测网络也有待不断加密和优化。     

Investigating the vibration properties of integrated ceiling systems considering interactions with surrounding equipment

Studies on recent earthquakes highlighted that buildings with minimal structural damage still suffer from extensive damage and failure of nonstructural components. The dropping and damage of suspended ceiling systems, which typically consist of acceleration-sensitive nonstructural elements, resulted in lengthy functional disruptions and extended recovery time. This article experimentally and analytically examined the vibration properties of an integrated ceiling system considering the interactions with surrounding electrical equipment. The theoretical stiffness and corresponding frequency of electrical equipment were initially derived and then verified by subsequent vibration tests and numerical analyses. The seismic performance of the air conditioner (AC) was evaluated with different installment configurations based on design spectra and floor response spectra. Vibration tests of the suspended integrated ceiling system considering the interactions with surrounding equipment showed that the inclusion of peripheral constraints increased the first horizontal vibration frequency of the ceiling system by a factor of approximately 6. The natural frequencies of all components in the integrated ceiling system were almost identical, which was attributed to the coupled behavior between the ceiling panels and surrounding equipment, emphasizing the effect of interactions between adjacent components during dynamic analysis. Based on the above experimental investigation, an associated numerical model of the integrated ceiling system was created. Finally, corresponding parametric studies that included the interactions with surrounding equipment, reinforcing braces of ACs and strengthening members at the rise-up location between two elevations were performed.     

2020年1月25日西藏丁青5.1级地震总结

2020年1月25日,藏东昌都丁青地区发生5.1级地震,尽管此次地震发生在监测能力较低地区,但震前仍监测到小震调制比高值、低b值等地震活动中短期异常。文中系统总结了地震构造背景、震源物理参数、序列特征以及震前出现的地震活动和地球物理观测等异常,结果发现：震源机制解显示为拉张型破裂,最近断裂为巴青—类乌齐断裂;序列活动特征、序列h值和b值计算结果显示,此次地震为主余型地震序列。目前,藏东地区仍存在一些地震活动和地球物理观测异常,表明该地区存在发生6级以上地震的强震背景,丁青5.1级地震的发生未能缓解该地区强震危险性。     

定常风对鄱阳湖水动力的影响

鄱阳湖属大风区,风场作为仅次于流域"五河"倾泻和长江顶托作用的另一重要驱动力,或在某些时刻影响局部区域的水流结构,进而影响局部水体中泥沙、污染物、营养盐等物质的输移和扩散.基于鄱阳湖二维水动力数学模型,模拟定常风场条件下的鄱阳湖流场分布及环流形式,并与无风条件下的水流时空结构进行对比.结果表明:3.03 m/s的NE向和SSW向定常风对湖泊水位影响微弱;对流速的影响主要集中在7月中旬至9月底的"湖相"期;其影响区域主要分布在湖区中部大湖面偏西岸及东部湖湾,约占湖泊最大水面积的16%;上述区域出现明显环流,环流结构具有时空异质性特点,环流区流速普遍增至无风时的两倍以上;NE向和SSW向风场产生的环流位置相近,方向相反.相比于以往鄱阳湖水动力研究中对风场的忽略,本次研究揭示了定常风场对鄱阳湖的重点影响区域、影响程度及影响形式,可为泥沙及污染物输移模拟中对风场条件的处理及可能带来的误差与误差的空间分布提供重要依据.     

富营养化高原浅水湖泊持续多年生态修复工程效果分析——以滇池大泊口为例

大泊口位于滇池草海南部,水域面积0.52 km²,平均水深约2 m,作为滇池草海重富营养化水域生态修复示范区,大泊口分别于2015和2019年开展了两期生态修复工程,经过近年来的系统治理,大泊口水生态治理效果初步显现。为分析探究成功修复湖区水质改善、生态系统企稳向好的原因,本研究选择2015年2月—2021年12月共7年的连续监测数据,根据工程开展情况以及水生态状况将大泊口水域划分为4个部分(A1～A4水域),首先分析4个区域内主要的水质指标(悬浮物(SS)、化学需氧量(COD_Cr)、总磷(TP)、总氮(TN)和叶绿素a(Chl.a))的变化趋势和相关性,其次探究不同类型生态工程的修复效果,最后与草海和外海水域进行对比,分析大泊口的治理效果。结果表明,治理后大泊口A1～A4水域的COD_Cr、TP和Chl.a稳定下降,COD_Cr分别降低18.65、27.96、25.26、40.92 mg/L,TP分别降低0.11、0.10、0.11、0.14mg/L,Chl.a分别降低0.037、0.068、0.06...