耐候钢中微量元素的测定

本文分别用化学法和电感耦合等离子体发射光谱法(ICP-AES)测定了Corten-B和Sten3两种耐候钢中Cr、Cu、Mn、Sb、Si、V、P、Ti等8种微量元素的含量,并与传统的化学法进行了对比.试验证明ICP-AES光谱法不但技术简便、快速、易于推广应用,而且ICP-AES光谱法和微波消解技术联用在微量元素测量上有更准确、安全等方面的优点.另外,ICP-AES仅通过对少量样屑的一次溶样即可得到全部元素的分析结果,节省了钢样,这对于难以取样的情况尤为有利.     

Transformations of particles, metal elements and natural organic matter in different water treatment processes

Characterizing natural organic matter （NOM）, particles and elements in different water treatment processes can give a useful information to optimize water treatment operations. In this article, transformations of particles, metal elements and NOM in a pilot-scale water treatment plant were investigated by laser light granularity system, particle counter, glass-fiber membrane filtration, inductively coupled plasma-optical emission spectroscopy, ultra filtration and resin absorbents fractionation. The results showed that particles, NOM and trihalomethane formation precursors were removed synergistically by sequential treatment of different processes. Preozonation markedly changed the polarity and molecular weight of NOM, and it could be conducive to the following coagulation process through destabilizing particles and colloids; mid-ozonation enhanced the subsequent granular activated carbon （GAC） filtration process by decreasing molecular weight of organic matters. Coagulation-flotation and GAC were more efficient in removing fixed suspended solids and larger particles; while sand-filtration was more efficient in removing volatile suspended solids and smaller particles. Flotation performed better than sedimentation in terms of particle and NOM removal. The type of coagulant could greatly affect the performance of coagulation-flotation. Pre-hydrolyzed composite coagulant （HPAC） was superior to FeCl3 concerning the removals of hydrophobic dissolved organic carbon and volatile suspended solids. The leakages of flocs from sand-filtration and microorganisms from GAC should be mitigated to ensure the reliability of the whole treatment system.     

人工园林大面积种植区土地利用/覆被变化对生态系统服务价值影响

近10a来由于经济利益的驱动,橡胶、茶园、咖啡和桉树等人工园林在云南省西南部西盟县大规模种植,使土地利用结构和布局发生了较大变化,影响了种植区的生态系统服务价值。以西盟县为研究对象,基于2000年、2005年和2010年的遥感影像解译的土地利用/覆被数据,参照"中国生态系统单位面积生态服务价值当量",修订了西盟县生态系统单位面积服务价值,结合敏感度分析,探讨了土地利用/覆被变化及其对生态系统服务价值的影响。结果表明:(1)2000~2010年西盟县的耕地、园地、水域和乡镇用地面积增加,林地和草地面积减少,西南部的土地利用/覆盖类型相互转化主要表现在林地和耕地转化为园地,而东北部表现在林地转化为耕地;(2)从时间上看,生态系统服务价值呈减少趋势,10 a间净减少106.29×106元,林地的生态系统服务价值始终最高;(3)研究期内,只有食物生产服务有价值量的增加,其余生态系统服务的价值量均为不同程度的减少;(4)从空间上看,西盟县生态系统服务价值东北部和东南部高,西部、中部和东部低。力所乡生态系统服务价值有小幅度增加,其余乡镇均呈减少趋势。西盟县以经济利益为目的的发展模式给生态系统服务和可持续发展带来巨大压力,在一定程度上使区域整体生态效应下降。因此,西盟县的发展应该在保证生态系统稳定的前提下,适当发展园地,同时优化土地利用结构,在生态效益和经济利益之间,找到双赢的平衡点。     

基于景观尺度的流域土地覆被变化及其水文响应

水资源短缺已成为限制华北地区社会经济发展的主要因子之一,其中山区来水减少问题已成为该区域水资源研究亟待解决的关键问题。采用景观格局分析法及统计学方法对华北土石山区典型流域--红门川流域土地/覆被变化及其水文动态响应进行分析。结果表明：(1)1990～2005年流域景观呈破碎化趋势,其中,优势景观林地在研究时段内面积变化不大;耕地、建设用地面积增加趋势显著,增幅分别为431%和444%;水域减少趋势最为明显,减幅达208%。(2)土地利用/覆被变化对流域径流有显著调节作用：随着土地结构不断优化,森林、耕地面积的增加,1998～2005年流域平均年径流系数较1990～1998年下降77%;丰、平和枯水年径流系数则分别减少64%、31%和85%;当剔除降水因素后,土地利用景观结构优化使得月径流系数减少16%～100%。(3)土地利用/覆被变化对流域径流的调节作用呈现季节性,植物生长季径流调节尤为显著     

南方冰冻雨雪灾害年的环流及气象要素异常的统计分析

利用NCEP/NCAR的2.5°×2.5°格点的逐日再分析资料,通过分析我国南方19个冰冻雨雪灾害年的36个冰冻雨雪天气个例的环流形势,总结了发生冰冻雨雪天气的4种天气类型:北脊南槽型、乌山脊型、横槽南支型和高纬低涡型,后两种天气类型持续时间长、影响范围广,极易造成南方严重的持续冰冻雨雪灾害;进一步分析南方持续冰雪天气的物理量场和要素场特征,结果表明,对流层低层850~700 hPa辐合中心较垂直上升速度中心提前1~2 d出现,预示低温雨雪增强;冻雨严重年份在700 hPa维持大于0℃的融化层,南支槽前的西南急流为雨雪天气提供了水汽和热量输送,这种配置利于冻雨天气的发展和维持。天气类型的建立及气象要素的统计有利于为南方冰雪灾害天气预测预警服务。     

Responding to a policy mandate to collaborate: structuring collaboration in the collaborative forest landscape restoration program

The Collaborative Forest Landscape Restoration Program (CFLRP) aims to expand the pace and scale of forest restoration on national forests in the United States. The program requires candidate projects to develop landscape-scale forest restoration proposals through a collaborative process and continue to collaborate throughout planning, implementation, and monitoring. Our comparative case analysis of the initial selected projects examines how existing collaborative groups draw on past experience of collaboration and the requirements of a new mandate to shape collaborative structures as they undertake CFLRP work. While mandating collaboration appears contrary to what is often defined as an informal and emergent process, mandates can encourage stakeholder engagement and renew commitment to overcome past conflict. Our findings also suggest that a collaborative mandate can lead to increased attention and scrutiny, prompting adjustments to collaborative process and structure. As such, mandating collaboration creates dynamic tensions between past experience and new requirements for collaborative practice.     

Removal of trace elements in three horizontal sub-surface flow constructed wetlands in the Czech Republic

Between March 2006 and June 2008 removal of 34 trace elements was measured on a monthly basis at three horizontal-flow constructed wetlands in the Czech Republic designed to treat municipal wastewater. In general, the results indicated a very wide range of removal efficiencies among studied elements. The highest degree of removal (average of 90%) was found for aluminum. High average removal was also recorded for zinc (78%). Elements removed in the range of 50-75% were uranium, antimony, copper, lead, molybdenum, chromium, barium, iron and gallium. Removal of cadmium, tin, mercury, silver, selenium and nickel varied between 25 and 50%. Low retention (0-25%) was observed for vanadium, lithium, boron, cobalt and strontium. There were two elements (manganese and arsenic) for which average outflow concentrations were higher compared to inflow concentrations. Reduced manganese compounds are very soluble and therefore they are washed out under anaerobic conditions.     

On causes of gigantism in herbaceous plants

Landscape-geochemical features providing for manifestation of gigantism in herbaceous plants have been revealed in natural habitats in the south of Sakhalin and Kunashir islands. Tall herb assemblages have proved to be associated with geochemical landscapes characterized by reducing (gley or hydrogen sulfide) conditions and increased contents of petroleum hydrocarbons and some trace elements (total and movable forms). A hypothesis is put forward that gigantism in herbaceous plants is manifested in zones of active faults, which serve as a kind of conduits supplying endogenous heat, matter, and water to the root systems.     

变电站建设中的电磁防护及环境和谐发展问题

随着我国经济水平的发展所带来的用电负荷的激增,变电站落户市区已是经济发展的必然结果。随即对变电站建设中的电磁防护提出了更高的要求;并全面考虑周边人类的生存环境。本文总结了变电站在规划建设中的电磁防护及如何与环境和谐发展的问题,并针对具体问题一一列举了所需采取的措施,包括抵御变电站电磁和噪声环境的防护措施,变电站二次系统抵御电磁骚扰源的措施以及变电站规划与景观的协调、最终将实现变电站建设与环境的和谐发展。     

城市滨水景观评价研究初探——以南京市莫愁湖滨水区为例

城市滨水区一直被认为是一个城市最具活力和生态价值的区域,但伴随着城市职能的转型以及水运地位的下降,世界上大部分的滨水区都经历了从繁荣到衰败的过程。然而目前,随着城市人群的生态需求与审美需求的进一步提高,城市滨水区又面临着复兴之势,这也对城市滨水号观设计以及作为其基础而存在的滨水景观评价提出了新的要求。因此。本文将以成分代用模式评价方法为指导,以南京市莫愁湖滨水区为案例对其进行景观评价,并基于此获取影响滨水区景观质量的重要因素,以期对以后的滨水区规划设计起到一定的指导作用。