Assessing the ‘two water worlds’ hypothesis and water sources for native and exotic evergreen species in south‐central Chile          下载免费PDF全文

P. Hervé‐Fernández  C. Oyarzún  C. Brumbt  D. Huygens  S. Bodé  N. E. C. Verhoest  P. Boeckx 《水文研究》2016,30(23):4227-4241

Recent studies using water‐stable isotopes (δ¹⁸O and δ²H) have suggested an ecohydrological separation of water flowing to streams or recharging groundwater and water used by trees, known as the ‘two water worlds’ (TWW) hypothesis. In this study, we measured water isotopic composition in precipitation [open field and throughfall, i.e. local meteoric water line (LMWL)] and the mobile water compartment (i.e. stream and soil solution), bulk soil water and xylem water over a period of 1.5 years in two headwater catchments: NF, covered with old growth native evergreen forest (Aetoxicon punctatum, Laureliopsis philippiana and Eucriphya cordifolia), and EP, covered with 4 and 16‐year‐old Eucalyptus nitens stands. Our results show that precipitation, stream and soil solution plot approximately along the LMWL, while xylem waters from all studied tree species plot below the LMWL, supporting the TWW hypothesis. However, we also found evidence of ecohydrological connectivity during the wet season, likely controlled by the amount of antecedent precipitation. These observations hold for all investigated tree species. On both sites, a different precipitation source for stream and xylem water was observed. However, in EP, bulk soil showed a similar precipitation source as xylem water from both E. nitens stands. This suggests that E. nitens may use water that is recharging the bulk soil compartment. We conclude that under a rainy temperate climate, the TWW hypothesis is temporal and does not apply during wet seasons. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

An Investigation of the Factors Affecting Saline Ice Melting Processes and Desalination          下载免费PDF全文

Yue Zhang  Jingsong Yang  Rongjiang Yao 《洁净——土壤、空气、水》2018,46(8)

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精河6.6级地震前精河水管仪、伸缩仪异常特征分析     

张智慧  李娜  邢喜民 《震灾防御技术》2018,13(3):671-678

2017年8月9日精河发生6.6级地震。本文首先利用相关、回归分析研究了气温对水管仪、伸缩仪的影响，并进行了干扰的定量剔除；其次，通过回归残差分析研究地震前水管仪、伸缩仪的异常特征，认为精河6.6级地震前存在3项异常:①2016年5月22日起，水管仪NS分量S倾幅度0.53"；②2017年3月24日起，EW分量E倾幅度0.28"；③2016年9月10日起，伸缩仪NS分量出现压缩现象。  相似文献   

Investigating Correlations and Variations of Air Pollutant Concentrations under Conditions of Rapid Industrialization – Kocaeli (1987–2009)     

Şenay Çetin Doğruparmak  Bilge Özbay 《洁净——土壤、空气、水》2011,39(7):597-604

In this study, it was aimed to characterize temporal variations of air pollutants for determining contribution to pollution episodes and to obtain correlations between these pollutants. With this aim we used data analysis for measured sulfur dioxide (SO₂), particulate matter (PM, black fume and PM10), nitrogen oxides (NO_x), ozone (O₃), carbon monoxide (CO), methane (CH₄), and non‐methane hydrocarbons (NMHC) recorded in Kocaeli, one of the most industrilizated cities of Turkey. Pollutant concentrations were the results of continuous and semi‐automatic measurements. Semi‐automatic measurements of SO₂ and PM (black fume) were enclosing period from 1987 to 2008 whereas continuous monitoring of all pollutants included years of 2007–2009. In the first stage of the study daily, monthly, annual, and seasonal variations of pollution were researched. Annual average concentrations were compared with limits set by Air Quality Protection Regulation (AQPR), Air Quality Evaluation and Management Regulation (AQEMR), World Health Organization (WHO), European Union (EU), and National Ambient Air Quality Standards (USEPA). In the following stage relationships between pollutants such as NO₂–O₃, NO_x–CO, NO_x–NMHC, and NO_x–SO₂ were investigated and correlation coefficients were determined as 0.87, 0.56, 0.51, and 0.69, respectively. R² values of regression models developed from these correlations were 0.78, 0.56, 0.34, and 0.72, respectively. Vehicle density of the traffic was evaluated with NO_x–O₃ emissions and decrease was seen in NO_x emissions due to decreasing vehicle density at weekends whereas O₃ concentrations increased. These correlations enable prediction of the parameters that cannot be measured which is important for providing improvement in early warning systems.  相似文献   

热磁技术方法条件实验及相关问题   总被引：1，自引：0，他引：1  

胡树起  马生明  刘崇民  李冰  席明杰 《物探与化探》2011,35(2):212-217

热磁技术方法条件实验主要包括焙烧粒度、温度、时间及热磁组分分离等实验内容,对各技术环节进行了设计、试验,确立了一套合理的样品焙烧、热磁组分分选的技术流程,并就实验中遇到的一些问题进行了分析探讨,为热磁地球化学方法的引入、推广提供了基础技术支持。  相似文献   

Determination of Trace Silver in Polymetallic Ore Samples by Flame Atomic Absorption Spectrometry after Solid‐Phase Extraction Using a Microcolumn Comprising Eggshell Membrane     

Xianzhong Cheng  Kun Shao  Shangyue Shen  Shenghong Hu  Haiou Qiu 《Geostandards and Geoanalytical Research》2011,35(4):461-469

A rapid and inexpensive method was developed for the determination of trace silver in polymetallic ore samples by use of eggshell membrane (ESM), a natural biomaterial, as the solid‐phase extraction (SPE) adsorbent coupled with flame atomic absorption spectrometry (FAAS). The ESM was used for the separation/pre‐concentration of silver, and the parameters affecting sensitivity, such as pH, sample flow rate, eluent volume and eluent flow rate, were carefully investigated. ESM was found to be an effective solid phase extractant for the adsorption of trace silver over a wide range of acidity from 0.02 to 0.50 mol l^?1 HNO₃. The sample solution in 0.4 mol l^?1 HNO₃ was pumped through an ESM microcolumn at the rate of 1.0 ml min^?1. Silver was absorbed, and then eluted with a solution of 1.0% m/v thiourea–0.5% v/v HCl. Under these optimal conditions, ESM exhibited a good enrichment efficiency for silver with a dynamic adsorption capacity of 1.7 mg g^?1. The proposed method was applied to the FAAS determination of trace silver in polymetallic ores and geological reference materials, GSO‐2, 3 and 5, and GSD‐11, GSD‐12, and the determined values were in good agreement with certified values.  相似文献   

海洋废弃钻井液处理技术研究     

徐良伟  马超  陈书明  雷宇 《海洋地质译丛》2011,(4):84-86,92

针对滨海-6井废弃钻井液的特点,提出了破胶-固液分离-固化的思想。通过实验优化破胶剂、絮凝剂、固化剂配方。实验结果表明：100mL废弃钻井液破胶剂加量为2g,絮凝剂为2gAS＋2．5％HPAM溶液（质量分数0．1％）,固液分层现象明显、出水水质透明。固化剂的加量为1．5％CJ-1、27．7％水泥、7．7％CJ-2,6．2％CJ-3。固化强度和浸出液试验表明：固化体在养护15天后平均强度3．0MPa,浸出液指标达到GB8978-1996《污水综合排放标准》二级标准。  相似文献   

含粗粒金矿样品采集加工与分析研究进展     

熊英  陈文科  田萍  吴邦朝 《岩矿测试》2015,34(1):12-18

含粗粒金矿,由于粗粒金的存在使其样品的采集、加工和分析极具挑战性,如何获得具有代表性和均匀性的化学分析样品,并提供准确的分析结果,长期以来一直是该类金矿资源勘查评价急待解决的技术难题。本文对近年来国内外含粗粒金矿样品的采集、加工和分析方法等3方面开展的研究工作及主要成果进行归纳分析,认为:1含粗粒金矿样品的采集是确保样品代表性的首要环节,含粗粒金矿样品分析结果的潜在误差有80%来源于样品采集,因此研究经济、有效的样品采集方法至关重要。2含粗粒金矿样品的加工主要从提高自然金的粉碎度,改进加工流程,选择样品加工设备等方面进行,但查明金的粒度分布及伴生矿物是拟定样品加工流程的关键。3含粗粒金矿样品的分析方法有常规的化学分析方法、批量浸金法和人工重砂加权平均法,相对于复杂的加工流程研究,后者有望成为此类样品经济有效的分析方法。本文指出,含粗粒金矿资源评价质量的误差来源于地质、采样、加工、分析等诸多方面,总体而言应最小化所有阶段误差,应特别重视样品采集方法的研究,确保采集样品的代表性是提高该类金矿资源评价质量的前提。  相似文献   

新型磁选装置的研制及其应用于分离超贫磁铁矿中的磁性铁   总被引：1，自引：1，他引：0  

黄瑞成  肖洁  魏灵巧  罗磊  付胜波 《岩矿测试》2015,34(2):213-217

磁性铁是超贫磁铁矿勘查中的基本分析项目之一,为准确测定磁性铁的含量,首先需要实现磁性铁的定量分离。目前常用的手工内磁选法由于所用磁铁的有效磁场强度难以保证,而且受人为操作的影响较大,导致分析结果的重现性差。本文应用50 m L滴定管、电磁铁和三相异步电动机,研制了一种新型磁选装置——电磁式磁性铁分选装置,实现了超贫磁铁矿中磁性铁与非磁性铁的定量分离,结合重铬酸钾容量法建立了超贫磁铁矿中磁性铁的分析方法。在选定的磁选条件下(电流2.5 A,磁选管运动频率40 r/min,磁选时间5 min)分析铁矿石标准物质,磁性铁的测定值与标准值的相对误差小于1.0%;分析采自实际矿区的超贫磁铁矿样品,磁性铁的测定结果与手工内磁选法一致,且相对标准偏差(RSD,n=5)小于1.0%,优于手工内磁选法的精密度。本方法采用的电磁式磁性铁分选装置有效地控制了磁场强度的强弱,避免永磁铁出现磁损失,同时可以量化磁性铁分离的参数,提高了磁性铁的分析精度。  相似文献   

http://www.sciencedirect.com/science/article/pii/S167498711300162X     

Fumiko Tajima  Masaki Yoshida  Eiji Ohtani 《地学前缘(英文版)》2015,6(1):79-93

Seismic observations have shown structural variation near the base of the mantle transition zone(MTZ)where subducted cold slabs,as visualized with high seismic speed anomalies(HSSAs),flatten to form stagnant slabs or sink further into the lower mantle.The different slab behaviors were also accompanied by variation of the "660 km" discontinuity depths and low viscosity layers(LVLs) beneath the MTZ that are suggested by geoid inversion studies.We address that deep water transport by subducted slabs and dehydration from hydrous slabs could affect the physical properties of mantle minerals and govern slab dynamics.A systematic series of three-dimensional numerical simulation has been conducted to examine the effects of viscosity reduction or contrast between slab materials on slab behaviors near the base of the MTZ.We found that the viscosity reduction of subducted crustal material leads to a separation of crustal material from the slab main body and its transient stagnation in the MTZ.The once trapped crustal materials in the MTZ eventually sink into the lower mantle within 20-30 My from the start of the plate subduction.The results suggest crustal material recycle in the whole mantle that is consistent with evidence from mantle geochemistry as opposed to a two-layer mantle convection model.Because of the smaller capacity of water content in lower mantle minerals than in MTZ minerals,dehydration should occur at the phase transformation depth,~660 km.The variation of the discontinuity depths and highly localized low seismic speed anomaly(LSSA) zones observed from seismic P waveforms in a relatively high frequency band(~1 Hz) support the hypothesis of dehydration from hydrous slabs at the phase boundary.The LSSAs which correspond to dehydration induced fluids are likely to be very local,given very small hydrogen(H~+) diffusivity associated with subducted slabs.The image of such local LSSA zones embedded in HSSAs may not be necessarily captured in tomography studies.The high electrical conductivity in the MTZ beneath the northwestern Pacific subduction zone does not necessarily require a broad range of high water content homogeneously.  相似文献