煤中铅的地球化学特征

铅属于重金属元素,也是煤中的有害元素之一,煤中的铅通过风化、燃烧等各种途径转移到大气、水以及土壤中,对环境造成严重危害。本文应用地球化学、矿物学、物理化学和环境化学等方法,对煤中铅的地球化学特征、赋存状态、迁移规律与富集机制进行了详细论述,为环保和脱铅工艺提供了科学依据。      

Global sensitivity analysis of DRAINMOD‐FOREST,an integrated forest ecosystem model

Global sensitivity analysis is a useful tool to understand process‐based ecosystem models by identifying key parameters and processes controlling model predictions. This study reported a comprehensive global sensitivity analysis for DRAINMOD‐FOREST, an integrated model for simulating water, carbon (C), and nitrogen (N) cycles and plant growth in lowland forests. The analysis was carried out for multiple long‐term model predictions of hydrology, biogeochemistry, and plant growth. Results showed that long‐term mean hydrological predictions were highly sensitive to several key plant physiological parameters. Long‐term mean annual soil organic C content and mineralization rate were mainly controlled by temperature‐related parameters for soil organic matter decomposition. Mean annual forest productivity and N uptake were found to be mainly dependent upon plant production‐related parameters, including canopy quantum use efficiency and carbon use efficiency. Mean annual nitrate loss was highly sensitive to parameters controlling both hydrology and plant production, while mean annual dissolved organic nitrogen loss was controlled by parameters associated with its production and physical sorption. Parameters controlling forest production, C allocation, and specific leaf area highly affected long‐term mean annual leaf area. Results of this study could help minimize the efforts needed for calibrating DRAINMOD‐FOREST. Meanwhile, this study demonstrates the critical role of plants in regulating water, C, and N cycles in forest ecosystems and highlights the necessity of incorporating a dynamic plant growth model for comprehensively simulating hydrological and biogeochemical processes. Copyright © 2013 John Wiley & Sons, Ltd.     

Holocene vegetation and climate dynamics of the boreal alpine ecotone of northwestern Fennoscandia

Climate change with respect to summer temperature throughout the Holocene is inferred from oscillations in the local Pinus sylvestris, Alnus incana and Betula pubescens forest‐lines, as recorded by fossil pollen and plant macrofossils in lake sediments at four altitudinal levels. Mt Skrubben (848 m a.s.l.), in Dividalen, was deglaciated down to below 280 m a.s.l. during 10 800–10 300 cal. yr BP. Betula pubescens established 10100 cal. yr BP at 280 m a.s.l. and expanded up to near the summit during the next 700 years. Birch woodland prevailed on the mountain plateau until 3300 cal. yr BP. Local Pinus sylvestris stands are recorded up to 400 m a.s.l. at 8450 cal. yr BP and >548 m a.s.l. about 8160 cal. yr BP. Alnus incana expanded from 400 to nearly 790 m a.s.l. during the period 7900–7600 cal. yr BP. The maximum forest distribution lasted until ca. 6000 cal. yr BP. Marked climatic deteriorations caused lowering of the forest‐lines around 4600 and 3000 cal. yr BP. Reconstruction of the summer temperature indicated mean July temperatures at 400 m a.s.l. of 1.5–3°C above the present during the period of maximum forest expansion, whereas >3°C above the present temperature at 548 m a.s.l. This is in accordance with other regional temperature reconstructions from northern Europe. Copyright © 2008 John Wiley & Sons, Ltd.     

城市生活垃圾填埋场污染风险评价

本文是在系统调查和收集各类资料的基础上,根据垃圾场地固有的防污性能和垃圾场与地下水水源保护区间的关系进行综合评价,垃圾场地内在风险采用灰色聚类法进行评价。垃圾场地下水污染风险评价可以为地下水污染防治和修复提供技术支持。     

土壤修复过程中重金属形态的研究综述

重金属污染土壤的修复是现阶段污染土壤治理中的难点之一,在土壤修复过程中对重金属的形态研究已在多个领域中开展,并且在重金属形态及其与生物有效性和毒性等研究领域取得了一定的成果。本文综述了现阶段在污染土壤修复过程中对重金属形态研究的主要领域,分析研究重金属形态的必要性,总结出土壤修复过程中重金属形态方面应当从重金属在土壤与植物中的存在形态入手,研究重金属元素在不同界面间的迁移转化规律,通过阻断重金属元素在污染源、土壤、生物之间的传递链条,以阻止重金属对生物体造成危害,从而为土壤重金属污染的治理修复提供理论基础。     

屏障效应对生物地球化学异常形成的影响及找矿有效指示植物的选择

采用光谱仪及透射电子显微镜对广西几个金属矿床的生物地球化学异常和植物细胞微观特征进行了研究,结果发现:生物地球化学异常对土壤地球化学异常有明显的物质性继承关系;生物地球化学异常的物质以金属聚集体(电子致高密度体物质)的形式沉淀在植物液胞中或细胞壁及膜边缘,其对植物的伤害可能只达到细胞或组织的水平.生物地球化学异常的形成...     

河南祁雨沟金矿及外围高植被区遥感找矿预测

应用ENVI4.8软件,对河南嵩县祁雨沟金矿及外围ETM+遥感数据通过主成分分析、彩色合成、直方图拉伸、监督分类等方法,成功地提取了高植被覆盖区遥感影像上金的植物地球化学异常信息。利用卷积滤波和形态学分析方法进行线性构造解译,利用计盒维数法求得研究区的线性构造分维值,得出本区线性构造具有良好的统计自相似性和分形特征。比较线性构造分维等值线图和植物地球化学异常图可知,线性构造集中区与植被异常区基本吻合,区内已知85%以上的矿点分布于植被异常和线性构造集中区。综合分析地层岩性、岩浆岩、矿点、线性构造分维等值线特征和遥感植被异常特征等信息,圈出了三级9个找矿靶区。     

节能型深部找矿长寿命金刚石钻头野外生产试验效果

为提高钻头寿命研究出新的胎体配方及烧结工艺,设计了新的钻头水路,使钻头胎体高度达到12～15mm,新钻头较普通钻头寿命有明显提高,达到试验研究目的。     

Extended survival of several organisms and amino acids under simulated martian surface conditions

Recent orbital and landed missions have provided substantial evidence for ancient liquid water on the martian surface as well as evidence of more recent sedimentary deposits formed by water and/or ice. These observations raise serious questions regarding an independent origin and evolution of life on Mars. Future missions seek to identify signs of extinct martian biota in the form of biomarkers or morphological characteristics, but the inherent danger of spacecraft-borne terrestrial life makes the possibility of forward contamination a serious threat not only to the life detection experiments, but also to any extant martian ecosystem. A variety of cold and desiccation-tolerant organisms were exposed to 40 days of simulated martian surface conditions while embedded within several centimeters of regolith simulant in order to ascertain the plausibility of such organisms’ survival as a function of environmental parameters and burial depth. Relevant amino acid biomarkers associated with terrestrial life were also analyzed in order to understand the feasibility of detecting chemical evidence for previous biological activity. Results indicate that stresses due to desiccation and oxidation were the primary deterrent to organism survival, and that the effects of UV-associated damage, diurnal temperature variations, and reactive atmospheric species were minimal. Organisms with resistance to desiccation and radiation environments showed increased levels of survival after the experiment compared to organisms characterized as psychrotolerant. Amino acid analysis indicated the presence of an oxidation mechanism that migrated downward through the samples during the course of the experiment and likely represents the formation of various oxidizing species at mineral surfaces as water vapor diffused through the regolith. Current sterilization protocols may specifically select for organisms best adapted to survival at the martian surface, namely species that show tolerance to radical-induced oxidative damage and low water activity environments. Additionally, any hypothetical martian ecosystems may have evolved similar physiological traits that allow sporadic metabolism during periods of increased water activity.     

基于CLM4.5的高寒草地辐射收支和水热交换的数值模拟研究

利用那曲高寒气候环境观测研究站本部BJ观测点2014年6-8月的近地层观测资料,结合CLM4.5陆面模型,探究空气动力学粗糙长度、叶面积指数、植被覆盖度和热力学粗糙长度参数化方案的改变对陆面能水平衡的模拟结果产生的影响,并且探讨了粗糙度及植被状态指数影响陆面能水平衡模拟性能的机制.结果表明:(1)CLM4.5默认的热力...