吸附法分离盐湖卤水中锂的研究进展

锂及其化合物是重要的化工原料,因其优越和独特的性能,需求量逐年增加。锂矿床类型主要有锂辉石、锂云母、透锂长石等固体型和盐湖型等液体矿。固体锂矿经过多年开发,采富弃贫,品质已临近经济下限,开发利用盐湖卤水和油田卤水中的锂资源日益受到重视。中国盐湖资源丰富,主要分布在青藏高原地区。盐湖中蕴藏着大量的锂资源,广泛应用于能源、化工、高科技等工业生产及居民生活领域,为保障资源供给和能源安全,分离盐湖中的锂资源十分迫切和必要。锂分离技术有吸附法、膜法、化学沉淀法、萃取法、结晶法、浮选法等,这些方法各有优势和不足,而吸附法适用于低品位、高浓盐、高镁锂比盐湖卤水中锂的分离。为此,总结了有关吸附法(电吸附)分离盐湖卤水中锂的原理、进展和优缺点,并总结和提出其发展方向。     

An uncertainty and sensitivity analysis approach for GIS-based multicriteria landslide susceptibility mapping

GIS-based multicriteria decision analysis (MCDA) methods are increasingly being used in landslide susceptibility mapping. However, the uncertainties that are associated with MCDA techniques may significantly impact the results. This may sometimes lead to inaccurate outcomes and undesirable consequences. This article introduces a new GIS-based MCDA approach. We illustrate the consequences of applying different MCDA methods within a decision-making process through uncertainty analysis. Three GIS-MCDA methods in conjunction with Monte Carlo simulation (MCS) and Dempster–Shafer theory are analyzed for landslide susceptibility mapping (LSM) in the Urmia lake basin in Iran, which is highly susceptible to landslide hazards. The methodology comprises three stages. First, the LSM criteria are ranked and a sensitivity analysis is implemented to simulate error propagation based on the MCS. The resulting weights are expressed through probability density functions. Accordingly, within the second stage, three MCDA methods, namely analytical hierarchy process (AHP), weighted linear combination (WLC) and ordered weighted average (OWA), are used to produce the landslide susceptibility maps. In the third stage, accuracy assessments are carried out and the uncertainties of the different results are measured. We compare the accuracies of the three MCDA methods based on (1) the Dempster–Shafer theory and (2) a validation of the results using an inventory of known landslides and their respective coverage based on object-based image analysis of IRS-ID satellite images. The results of this study reveal that through the integration of GIS and MCDA models, it is possible to identify strategies for choosing an appropriate method for LSM. Furthermore, our findings indicate that the integration of MCDA and MCS can significantly improve the accuracy of the results. In LSM, the AHP method performed best, while the OWA reveals better performance in the reliability assessment. The WLC operation yielded poor results.     

Advances in thermokarst lake research in permafrost regions

A thermokarst lake is defined as a lake occupying a closed depression formed by ground settlement following thawing of ice-rich permafrost or the melting of massive ice. As it is the most visible morphologic landscape developed during the process of permafrost degradation, we reviewed recent literature on thermokarst studies, and summarized the main study topics as： development and temporal evolution, carbon release, and ecological and engineering influence of thermokarst lakes. The climate warming, forest fires, surface water pooling, geotectonic fault and anthropogenic activity are the main influencing factors that cause an increase of ground temperatures and melting of ice-rich permafrost, resulting in thermokarst lake formation. Normally a thermokarst lake develops in 3–5 stages from initiation to permafrost recovery. Geo-rectified aerial photographs and remote sensing images show that thermokarst lakes have been mainly experiencing the process of shrinkage or disappearance in most regions of the Arctic, while both lake numbers and areas on the Qinghai-Tibet Plateau have increased. Field studies and modeling indicates that carbon release from thermokarst lakes can feedback significantly to global warming, thus enhancing our understanding of the influences of thermokarst lakes on the ecological environment, and on regional groundwater through drainage. Based on field monitoring and numerical simulations, infrastructure stability can be affected by thermal erosion of nearby thermokarst lakes. This review was undertaken to enhance our understanding of thermokarst lakes, and providing references for future comprehensive studies on thermokarst lakes.     

Estimation of higher chlorophylla concentrations using field spectral measurement and HJ-1A hyperspectral satellite data in Dianshan Lake,China

Based on in situ water sampling and field spectral measurements in Dianshan Lake, a semi-analytical three-band algorithm was used to estimate Chlorophylla (Chla) content in case II waters. The three bands selected to estimate Chla for high concentrations included 653, 691 and 748 nm. An equation, based on the difference in reciprocal reflectance between 653 and 691 nm, multiplied by reflectance at 748 nm as [R_rs⁻¹(653) − R_rs⁻¹ (691)] R_rs(748), explained 85.57% of variance in Chla concentration with a root mean square error (RMSE) of <6.56 mg/m³. In order to test the utility of this model with satellite data, HJ-1A Hyperspectral Imager (HSI) data were analyzed using comparable wavelengths selected from the in situ data [B₆₇⁻¹(656) − B₈₀⁻¹(716)] B₈₇(753). This model accounted for 84.3% of Chla variation, estimating Chla concentrations with an RMSE of <4.23 mg/m³. The results illustrate that, based on the determined wavelengths, the spectrum-based model can achieve a high estimation accuracy and can be applied to hyperspectral satellite imagery especially for higher Chla concentration waters.     

利用卫星测高监测贝加尔湖湖面高变化

以贝加尔湖为例,利用Jason-2测高卫星4年(2008~2012)GDR数据,经过误差改正与数据编辑,通过分析贝加尔湖月水位异常时间序列,得到了贝加尔湖湖面高变化的季节性规律;通过分析贝加尔湖半年水位异常时间序列,得出了贝加尔湖湖面高变化的周期为1年;计算结果表明,利用卫星测高技术对内陆湖泊湖面高变化进行监测具有一定的可行性。     

柴达木盆地盐湖资源管理信息系统的设计与实现

建立基于GIS技术的柴达木盆地盐湖资源管理信息系统,可以为盐湖资源开发管理与高效利用提供信息化的决策咨询平台。文章在分析盐湖资源循环利用管理需求的基础上,讨论了柴达木盐湖资源管理软件系统的构架和功能目标,分析了系统设计流程和实现技术。通过运用C#语言和ArcGIS Engine组件技术,基于.NET框架的Microsoft Visual Studio 2008集成开发环境,实现了柴达木盆地盐湖资源分布的三维场景浏览、盐湖企业及其生产经营状况的查询分析和盐湖资源开发的动态管理,为循环经济区盐湖资源的可持续利用提供了技术支持。     

洱海盆地水面与地面气象要素变化特征的比较

依据大理国家气候观象台在洱海湖中建立的自动观测系统以及大理国家基本气象站观测资料,对2008至2009年的风、温、湿、压、降水要素的日变化和季节变化特征进行了对比分析。结果表明：受局地复杂地形和洱海的影响,洱海盆地近地层常年存在湖陆风、山谷风、峡谷风三者叠加效应引起的局地环流。水面盛行风向白天以东南风为主,夜间以东南风和西西南风为主,而地面白天以东东南风为主,夜间以静风和西西北风为主。年平均风速小,水面为2.9m/s,地面为2.4m/s。水面年平均气温为16.8℃,而地面为16.0℃。两观测点气温、相对湿度、气压均表现出明显的日变化特征,水面气温、相对湿度出现极大值和极小值的时间均比地面晚。全年降水多集中在5—10月。     

基于MODIS影像的西藏典型内陆湖泊变化研究及成因分析

根据2002-2009年的MODIS卫星遥感数据和2000-2009年的气温、地表温度、降水量、相对湿度等气象资料分析得出,2002-2009年西藏典型湖泊面积变化显著：位于西藏藏北地区的色林错、当热雍错、扎日南木错湖泊面积呈扩大趋势,在8 a内分别增长了241.97 km2、12.8 km2、11.69 km2;位于...     

Zooplankton community structure and ecology of the tropical-highland Lake Hayq, Ethiopia

Lake Hayq, a highland lake in Ethiopia, was stocked with Tilapia fish (Oreochromis niloticus) in late 1970s, offering an opportunity to study the effect of fish predation in a natural lake. Since 1930s, some limnological surveys have been done sporadically documenting a change in zooplankton composition including the disappearance of cladocerans, hypothesizing the stocked planktivorous fish could be a cause. Nevertheless, no detailed research was conducted to identify potential effects of fish stocking predominantly due to its remote location. The article presents data about zooplankton composition, abundance and biomass done between October 2007 and January 2009 on short-time intervals including the underlying limnological variables. The zooplankton community was depauperate comprising two copepods, three cladocerans, and six rotifers taxa, as typical for tropical lakes. Total mean standing biomass of all crustacean zooplankton was 237 mg dry mass m⁻³, which gave Lake Hayq an intermediate position when compared with other tropical lakes. Of copepods, Thermocyclops ethiopiensis was almost an exclusive species, and its temporal variation was influenced by food supply and water temperature. We refute the hypothesis that Tilapia was the cause for the seasonal disappearance of cladocerans, and attribute it to the adverse effect of episodic mixing. Nevertheless, the planktivorous fish probably plays a key role in structuring the cladocerans in particular the large-sized Daphnia magna. In January 2008, we observed a massive planktivorous fish mortality that triggered high algal biomass, which was later grazed by large-sized D. magna demonstrating the trophic cascade hypothesis in a natural ecosystem.     

Evaluation of meteorological controls of reconstructed rockfall activity in the Czech Flysch Carpathians

Rockfall is an important process in the final sculpturing of escarpments and scree slopes that originate in bedrock landslides in the Flysch Carpathians. The spatio‐temporal characteristics of rockfall activity were studied at four localities representative of old landslides in the highest part of the Czech Flysch Carpathians (Moravskoslezské Beskydy Mountains). Historical activity, chronology, and spatial context of rockfall activity were reconstructed using dendrogeomorphic techniques and rockfall rate index (RR). A total of 1132 increment cores from 283 trees growing in the rockfall transport and accumulation zones enabled the dating of 989 rockfall events. Reconstruction of a 78‐year‐long RR chronology suggests similar rockfall histories and trends at all study sites, indicating the existence of major common factors driving rockfall dynamics in the region. Temporal analysis and correlation of the RR series obtained with monthly mean temperatures, numbers of days with temperature transitions through 0 °C and monthly precipitation totals show that meteorological characteristics have evident but variable influence on rockfall activity. The most important factor is the effect of freeze–thaw cycles throughout the year, supplemented by low temperatures, especially during autumn. The influence of precipitation totals is of lesser importance. Copyright © 2011 John Wiley & Sons, Ltd.