黄土塬区苹果种植对深剖面土壤水分和地下水补给的影响

通过对长武黄土塬区不同林龄苹果林地下0~20 m深剖面土壤湿度及土壤水氯离子浓度测定,定量分析了黄土塬区苹果种植对厚深黄土剖面土壤水分及地下水补给的影响。结果表明：随着林龄增加,苹果林地深剖面土壤水分由浅及深逐年降低,深层土壤储水量呈倒“S”曲线趋势下降,27龄之后进入稳定期。丰水年份形成的活塞流是黄土塬区深层渗漏以及地下水补给的主导方式,农田下地下水年均潜在补给量为30.2 mm,占年均降水量的5.2%。农田转换为苹果林地后形成的深厚土壤干层将阻断降水对地下水的补给,减弱地下水补给过程中活塞流的主导作用。需通过政策引导协调农果面积比例,保证地下水资源持续补给,达到可持续利用的目的。     

三元体系RECl_3（RE＝La，Pr，Sm）－HOAc－H_2O（30℃）的

本文测定了三元系ＲＥＣｌ３（ＲＥ＝Ｌａ，Ｐｒ，Ｓｍ）－ＨＯＡｃ－Ｈ２Ｏ（３０℃）的平衡态的溶度数据并绘制了相应的溶度图．在三个体系中分别形成ＬａＣｌ３·７Ｈ２Ｏ，ＰｒＣｌ３·６Ｈ２Ｏ，ＳｍＣｌ３·６Ｈ２Ｏ三种物质．ＨＯＡｃ对ＬｓＣｌ３·７Ｈ２Ｏ，ＰｒＣｌ３·６Ｈ２Ｏ，ＳｍＣｌ３·６Ｈ２Ｏ盐析作用程度的不同，表明了轻稀土元素的“一分组效应”，同时依据ＨＯＡｃ对ＬａＣｌ３·７Ｈ２Ｏ，ＰｒＣｌ３·６Ｈ２Ｏ，ＳｍＣｌ３·６Ｈ２Ｏ有盐折作用这一结论，提出了一种制备ＬａＣｌ３·７Ｈ２Ｏ，ＰｒＣｌ３·６Ｈ２Ｏ，ＳｍＣｌ３·６Ｈ２Ｏ的新方法．     

甘肃平凉钙基膨润土的有机改性与表征

针对甘肃平凉产钙基天然膨润土进行不同钠化试剂、反应时间,反应介质、温度等条件的钠化工艺研究,得出最佳钠化合成工艺,并制得十六烷基氯化吡啶(CPC)改性膨润土.研究该有机改性膨润土红外光谱、X射线衍射、热重分析及分散性结果表明,插层剂CPC已进入膨润土的片层同.使有机改性膨润土的层间距由1.04 nm增加到2.11nm,热失重率达17%,新型有机改性膨润土在有机介质中表现出很好的分散性.     

全国土壤污染状况详查重金属元素可提取态提取试剂的选择

土壤重金属元素可提取态是衡量其生物有效性的重要指标,但其含量随着土壤酸碱性等环境条件的变化而改变,在提取土壤重金属元素可提取态时,不可避免地面临着提取剂与提取方法的选择。中国有关土壤重金属元素可提取态的标准分析方法或技术规范涉及的提取剂多达7种(pH=5.8盐酸溶液、0.1mol/L盐酸溶液、0.43±0.02mol/L硝酸溶液、0.11mol/L乙酸溶液、1mol/L硝酸铵溶液、0.005mol/L DTPA浸提剂、0.01mol/L氯化钙溶液),不同学者对不同提取剂有不同的研究结论,对于通用提取剂的系统研究未见报道。本文选择代表性农耕土壤样品,采用以上7种提取剂提取其中8种重金属元素(镉镍铜锌铬铅砷汞),电感耦合等离子体质谱法(ICP-MS)测定镉铬铜铅锌镍含量,原子荧光光谱法(AFS)测定砷和汞含量,对比了7种提取剂对各重金属元素的提取率,并研究了土壤酸碱性质对重金属元素提取率的影响。结果表明：(1)稀酸溶液对土壤重金属元素的提取率较高,且与土壤的酸碱性无关;(2) 1mol/L硝酸铵溶液虽然对镉的提取能力表征了镉在酸性土壤中的活性远大于碱性土壤的特点,但其对碱性土壤中铅的提取率...     

白云石镁水泥材料的初步研究

以活性较高的苛性白云石粉和氯化镁溶液制备白云石镁水泥材料。研究氧化镁、氯化镁和水不同配比条件下对白云石镁水泥材料的抗压强度、相组成以及形貌的影响。在所研究的配比条件下,以氧化镁、氯化镁和水摩尔比为3.38∶1.00∶16.86和3.24∶1.00∶16.26配比的镁水泥样块强度较高,结构致密,水化物胶凝相稳定;氯化镁加入量较低,水的加入量较高会使镁水泥试块强度不高;氯化镁加入量较高,水的加入量较低会使镁水泥试块吸潮返卤现象严重,导致强度逐渐下降。     

氯化锌活化法制备软锰矿——核桃壳活性炭的研究

文章对氯化锌活法制备软锰矿-核桃壳活性炭进行了研究,考察了软锰矿投加量、氯化锌浓度、活化温度、活化时间等因素对软锰矿-核桃壳活性炭碘吸附值以及比表面积的影响。结果表明:软锰矿的投加量占核桃壳质量的8%、氯化锌浓度为3mol/L、活化温度为550℃左右、活化时间为120min是最佳的制备软锰矿-核桃壳的条件;在此条件下制得的活性炭碘吸附值为1,158.05mg/g,比表面积为787.540m2/g,较未添加软锰矿的核桃壳活性炭,碘吸附值和比表面积分别提高了11.5%和22.0%。     

Deep drainage sensitivity to climate,edaphic factors,and woody encroachment,Oklahoma, USA

Because groundwater is Earth's largest pool of freshwater, understanding the sensitivity of deep drainage to climate, soils, and land cover is critical in managing water resources. To better understand controls on this critical flux in the context of woody encroachment, we determined the sensitivity of deep drainage to climate, soil texture, soil compaction, rooting depth, growing season duration, and plant–water stress response using Hydrus‐1D to simulate deep drainage. To evaluate the simulation results, we compared these results with ground measurements at two anchor sites. At both anchor sites, Hydrus‐1D predictions of deep drainage matched measured values within the errors inherent in ground measurements. Sensitivity analysis suggested greatest sensitivity of deep drainage to climate (24 mm yr^?1) and rooting depth (12 mm yr^?1), moderate sensitivity to growing season duration (5 mm yr^?1) and soil texture (4 mm yr^?1), and lowest sensitivity to topsoil compaction and plant–water stress response (3 mm yr^?1). The sensitivity analysis indicated the relative importance of the plant‐related factors considered, which, in decreasing order, were rooting depth, growing season duration, and plant–water stress response – factors that change concomitantly as a result of forestation or woody encroachment. Further ground‐truth measurements of woody encroachment effects on deep drainage are needed to confirm or refine the results of this simulation modelling study. Copyright © 2015 John Wiley & Sons, Ltd.     

A tracer‐based simulation approach to quantify seasonal dynamics of surface‐groundwater interactions in the Pantanal wetland

The Pantanal wetland is one of the least explored regions of South America. It is characterized by an outstanding flora and fauna adapted to a seasonal flood pulse controlled by a dry and a wet season within each year. The resulting inundation covers in average an area of approximately 150 000 km² and is seen as the most important driver for ecological integrity. Evaporation from the large floodplain is supposed to influence the climate of the whole continent. The regional groundwater is connected to the surface water and plays an important role for the characteristic flooding regime by regulating the wetland's water table. The water balance assessment of the wetland and the internal water exchange between surface and groundwater is therefore of high relevance for the conservation of the Pantanal biodiversity. Despite of its importance, water balance studies including groundwater–surface water interactions based on field data are rarely undertaken. This is mainly due to the remoteness and difficulty in accessing this area, which results in lack of data. In our study, we developed a new tracer‐based model to simulate the spatio–temporal surface and subsurface fluxes for a range of water bodies. The model was able to simulate these fluxes considering a dynamic simulation of inflow and outflow using a newly collected 2‐year dataset of water levels, stable water isotopes and chloride collected from several water bodies in the northern Pantanal region. Quantitative differences between water bodies according to their location in the floodplain were determined by the flooding regime and connectivity as well as site‐specific characteristics, such as hydraulic conductivity and water depth. Our model simulated water balance fluxes with a Nash–Sutcliffe efficiency of 0.61, whereas it simulated stable water isotopic compositions better than chloride. We present the first study based on field data for the Pantanal, which is able to quantify water balances fluxes. Because their representation in global climate and land cover products is insufficient, our simulation results are valuable for validating large‐scale models. Copyright © 2016 John Wiley & Sons, Ltd.     

X-ray Diffraction of Dust Particles in Spring Beijing

X-ray diffractometry was utilized to study the mineralogical characteristics of the inhalable particles (PM10) sampled during two dust storms in Beijing city on March 18th and May 21st, 2008. We confirm, for the first time, that there stably exists ammonium chloride in the atmosphere when temperature is low. The total sulfates particles were affected by relative humidity. Both species and concentration of sulfates decreased first and then grew back by the end of each dust storm. Koninckite, a phosphate mineral never reported as particulate aerosol before, was identified. Meanwhile, our result shows that a chemical modification on dust minerals occurs during long range transportation. PM10 samples collected during the period of dust storms were dominated by crustal minerals such as quartz, illite/ smectite, illite, chlorite, feldspar and calcite, and were notably higher in concentration than that in normal periods of time. The amounts of total sulfates, calcite and feldspar altered in each dust storm. It is derived from 24-hour isentropic backward trajectories that two dust events in spring 2008 originated in different sources.     

黑云母与氯化物热水溶液相互作用的实验研究

本文在500℃和1×108Pa条件下，利用冷封口高温高压水热系统和焊封金管技术实验研究了黑云母和Na－Ca－氯化物溶液的相互作用，着重考察反应不同时间的黑云母表面和溶液化学的变化。黑云母中的K、Fe和Si不同程度地进入溶液相，而溶液中原有的Na和Ca含量降低；SEM／EDAX和EMAX研究表明，反应后的黑云母边缘部分明显失去K和Fe，应得到相当数量的H2O和一些Ca。黑云母中Fe活化的控制反应可能是H+交代作用。