微波超视距雷达大气波导环境

针对岸基/舰载微波超视距雷达远距离海上低空或海面目标探测的实际需求,首先对大气波导的直接测量和遥感反演等探测方法进行了分析比较,基于对大气波导形成机制和中尺度数值预报模式的分析,指出了有效预报大气波导需要解决的3个基本问题,最后对微波超视距雷达电波传播模型和评估方法进行了讨论。     

浸渍-微波法载铁活性炭对双酚A的吸附

通过浸渍-微波法制得载铁粉末活性炭,并用XRD、Boehm滴定法、碘吸附值和亚甲基蓝吸附值对其进行了物化表征,研究了其对双酚A的吸附性能。结果表明:经改性后,铁在活性炭上的负载形态主要为α-Fe和Fe3O4;活性炭的石墨化程度降低,碳的表面裸露点有所减少;载铁活性炭表面碱性含氧基团含量显著增加,表面酸性含氧基团含量减少;碘吸附值和亚甲基兰吸附值分别增加了28.25%和29.63%,即微孔率及中孔率均有所提高。载铁活性炭对双酚A的吸附等温线可以用Freundlich方程拟合,相关系数R2>0.900,原活性炭和载铁活性炭的吸附常数Kf分别为1.940 mg.L1/n/(g.mg1/n)和2.250 mg.L1/n/(g.mg1/n);载铁活性炭对双酚A的吸附动力学过程可以用Lagergren准二级动力方程拟合,相关系数R2>0.990,原活性炭和载铁活性炭的吸附速率常数Kad分别为0.014 min-1和0.021 min-1。     

Dynamic floodplain vegetation model development for the Kootenai River, USA

The Kootenai River floodplain in Idaho, USA, is nearly disconnected from its main channel due to levee construction and the operation of Libby Dam since 1972. The decreases in flood frequency and magnitude combined with the river modification have changed the physical processes and the dynamics of floodplain vegetation. This research describes the concept, methodologies and simulated results of the rule-based dynamic floodplain vegetation model "CASiMiR-vegetation" that is used to simulate the effect of hydrological alteration on vegetation dynamics. The vegetation dynamics are simulated based on existing theory but adapted to observed field data on the Kootenai River. The model simulates the changing vegetation patterns on an annual basis from an initial condition based on spatially distributed physical parameters such as shear stress, flood duration and height-over-base flow level. The model was calibrated and the robustness of the model was analyzed. The hydrodynamic (HD) models were used to simulate relevant physical processes representing historic, pre-dam, and post-dam conditions from different representative hydrographs. The general concept of the vegetation model is that a vegetation community will be recycled if the magnitude of a relevant physical parameter is greater than the threshold value for specific vegetation; otherwise, succession will take place toward maturation stage. The overall accuracy and agreement Kappa between simulated and field observed maps were low considering individual vegetation types in both calibration and validation areas. Overall accuracy (42% and 58%) and agreement between maps (0.18 and 0.27) increased notably when individual vegetation types were merged into vegetation phases in both calibration and validation areas, respectively. The area balance approach was used to analyze the proportion of area occupied by different vegetation phases in the simulated and observed map. The result showed the impact of the river modification and hydrological alteration on the floodplain vegetation. The spatially distributed vegetation model developed in this study is a step forward in modeling riparian vegetation succession and can be used for operational loss assessment, and river and floodplain restoration projects.     

赤泥对土地处理系统中植物除磷效果的影响研究

将赤泥按0％、2.5％、5％、7.5％、10％的重量比例与土壤混合,考察赤泥掺混对土地处理系统中植物除磷效果的影响.结果表明,赤泥从生物量以及磷吸收两方面影响植物除磷.适量的赤泥掺混可提高植物生物量,掺混比为5％时生物量最大.另一方面,赤泥掺混越多,对植物磷吸收的抑制也越大.总体效果上,掺混比例为5％时,黑麦草和高羊茅...     

A revised calculation of the econometric factors α- and β for the Extended Exergy Accounting method

Extended Exergy Accounting (“EEA”) is a method to compute the space- and time integral of the primary exergy required to produce a good or a service: the extended exergy of a commodity measures its “embodied exergy”, including externalities (Labour, Capital and Environmental Costa). A crucial point of the method is the calculation of two econometric coefficients, commonly referred to as “α” and “β”,used to calculate the extended exergy equivalents of Labour and Capital respectively. In previous applications of the EEA method, these coefficients have been assigned approximate values estimated on the basis of global system considerations. In this paper, a novel procedure is described that leads to the calculation of “exact” values of both econometric coefficients, based on detailed exergy- and monetary balances of the Society to which the EEA is applied. It is shown that both α and β depend in a non-trivial way from the consumption patterns, the technological level and the life- and socio-economic standards of each Country. It is also shown that the values are substantially different for developed (OECD) and underdeveloped Countries, and representative samples of values are calculated and critically analysed. On the basis of these new model coefficients, the specific exergy equivalents of Labour (ee_L) and of Capital (ee_K) are calculated, and shown to differ from the values used in previous EEA calculations.     

半干旱黄土区退耕还林十年植被恢复变化分析——以陕西吴起县为例

黄土高原退耕还林（草）政策实施已逾10 a,了解植被恢复变化状况及存在的问题,对于制定和完善生态环境治理方略具有重要意义。以吴起县为例,基于实地调查及遥感等数据,对退耕还林（草）以来植被覆盖度、主要植被类型变化及不同立地条件下植被恢复变化的差异进行了定量分析。结果表明：2000年至2009年,植被覆盖度大于30%的面积在全县总面积中的比例由不足1%上升至91.96%;其中缓坡立地类型上的乔灌林地类型面积增长最为显著,而阳向陡坡等恶劣生境下的植被恢复缓慢;有林地、灌木林地及疏林地均呈现规模增大趋势,属扩张状态;中覆盖度草地、低覆盖度草地、坡耕地及耕地呈现规模减少趋势,属缩减状态。     

内蒙古地区近25年植被对气温和降水变化的影响

利用1982—2006年内蒙古地区GIMMS-NDVI和降水量、气温数据,分析了不同植被类型对气温和降水变化趋势的影响。结果表明：近25年来内蒙古地区气温整体上呈上升趋势,降水量呈微弱降低趋势,西部荒漠区呈暖湿化趋势,中东部草原、森林等植被类型区呈暖干化趋势;从不同植被类型NDVI与平均气温和降水量的变化趋势率相关分析表明,NDVI值越低,升温趋势越明显,其中春季和秋季各植被类型间NDVI与季均气温升高趋势率呈显著和较显著的相关,夏、冬季关系不明显;植被NDVI越高,降水量减少趋势越明显。基于栅格的NDVI与气温升高幅度、降水变化趋势相关分析表明,年均气温升高幅度基本随NDVI的增加而降低,其中春、夏和秋季的季均气温升高幅度均随NDVI的增加而显著降低,冬季趋势不明显;而年降水量减小趋势率随植被NDVI的增加而显著增加,其中春季和冬季NDVI变化对降水的变化几乎没有影响;夏季和秋季均表现为随NDVI的增加,降水减小趋势率呈增加趋势。     

Treatment of Heavy Oil Contaminated Sand by Microwave Energy

Abstract Microwave (MW) was applied to enhance the removal of heavy oil (diesel and marine fuels) from contaminated sandy soil using granular activated carbon (GAC) as the dielectric medium. Adding GAC to the surface layer of the sand containing diesel fuel or marine fuel and subjecting the soil to 700 W MW irradiation for 30?s led to better removal efficiencies than without GAC addition by 9.5% (92.5% vs. 83%) for diesel fuel, and 11.5% (89.5% vs. 78%) for marine fuel. Additionally, GAC is an excellent MW absorbing material for converting MW energy into thermal energy. When GAC is added as the dielectric medium to convert the MW energy, the soil temperature rose from 52°C to 64°C, because the heat was transferred from GAC to the soil through GAC–soil interface. Meanwhile, volatile gas contained in the soil passes through the soil-GAC interface to reach the high-temperature GAC where the heavy oil is thermally cracked.     

安太堡露天矿复垦地不同人工植被恢复下的土壤酶活性和肥力比较

人工重建植被是露天矿复垦地植被恢复,提高土壤质量的主要途径之一.选择适宜的人工植被对快速恢复土壤质量具有重要意义.本文主要研究了安太堡露天矿复垦地油松-刺槐-柠条混交林、沙棘-刺槐-柠条-沙枣混交林和苜蓿地的土壤养分含量及酶活性,综合评价了这3种不同植被类型对土壤肥力恢复效果.结果表明,随着植被恢复的进行,土壤养分含量均有增加,油松-刺槐-柠条混交林的土壤养分含量显著高于其它样地.从以养分含量和酶活性权重计算的土壤综合肥力指标值(IFI)可知,油松-刺槐-柠条混交林IFI值最高.综合来看,对土壤重建效果最好的为油松-刺槐-柠条混交林,其次是沙棘-刺槐-柠条-沙枣混交林,再次为苜蓿.     

Cr(VI) removal from aqueous solution with bamboo charcoal chemically modified by iron and cobalt with the assistance of microwave

Bamboo charcoal (BC) was used as starting material to prepare Co-Fe binary oxideloaded adsorbent (Co-Fe-MBC) through its impregnation in Co(NO3)2 , FeCl3 and HNO3 solutions simultaneously, followed by microwave heating. The low-cost composite was characterized and used as an adsorbent for Cr(VI) removal from water. The results showed that a cobalt and iron binary oxide (CoFe2O4 ) was uniformly formed on the BC through redox reactions. The composite exhibited higher surface area (331 m2/g) than that of BC or BC loaded with Fe alone (Fe-MBC). The adsorption of Cr(VI) strongly depended on solution pH, temperature and ionic strength. The adsorption isotherms followed the Langmuir isotherm model well, and the maximum adsorption capacities for Cr(VI) at 288 K and pH 5.0 were 35.7 and 51.7 mg/g for Fe-MBC and Co-Fe-MBC, respectively. The adsorption processes were well fitted by the pseudo second-order kinetic model. Thermodynamic parameters showed that the adsorption of Cr(VI) onto both adsorbents was feasible, spontaneous, and exothermic under the studied conditions. The spent Co-Fe-MBC could be readily regenerated for reuse.