青藏高原东北边缘桦木林木本植物种间联结

青藏高原东北边缘地区位于我国东部季风区、西北干旱区与青藏高原高寒区的交汇地带,该区既兼具3大自然区的特点,又具有边缘地带气候波动不稳定性和自然生态环境的脆弱性,是全球变化重点监测的地区之一。研究青藏高原东北边缘亚高山桦木林的种间联结,不仅有助于更深刻地认识该地区桦木群落的结构、功能和演替,对于维持该地区群落稳定性以及生态恢复具有重要意义。本文选取青藏高原东北边缘桦木林中20个优势种,采用方差比率法(VR)检验多物种间的联结性,2×2列联表分析共同出现百分率(JI)、点相关系数(Ф)、Dice指数(DI)来表示种间联结程度,用重要值的Pearson相关和Spearman秩相关来检验相伴出现的机率等方法分析其种间关联性。结果表明:群落总体联结VR值为1.094,说明20个种群间表现出净正关联,其统计量W值为10.94说明20个种群之间在总体上的正关联不显著;大多数种对的JI值、DI值在0.4以下,说明种对之间联结程度不显著,Φ值大部分处于[-0.2, 0.2]值域内,说明种对之间的正或负的联结性较弱;而Spearman秩相关所测得的正负关联比要大于Pearson相关所测得的,且Spearman秩相关要优于Pearson相关。从以上结果可以看出,青藏高原东北边缘三种桦树天然次生林处于不稳定的状态,即演替的中期阶段,其逐渐会被地带性植被所取代。     

灾害地貌链及其临界过程初探

在灾害链定义的基础上提出了灾害地貌链的定义 (即由地貌灾害所构成的灾害链 ) ,基于不同的标准将其划分为不同的种类 ,运用苏姆的地貌临界理论对地貌灾害中的两种临界进行浅析 ,最后运用耗散结构理论来探讨灾害地貌链中的临界过程。     

Migration of manganese and iron during the adsorption-regeneration cycles for arsenic removal

Fe-Mn binary oxide incorporated into porous diatomite (FMBO-diatomite) was prepared in situ and regenerated in a fixed-bed column for arsenite [As(III)] and arsenate [As(V)] removal. Four consecutive adsorption cycles were operated under the following conditions: Initial arsenic concentration of 0.1 mg·L^-1, empty bed contact time of 5 min, and pH 7.0. About 3000, 3300, 3800, and 4500 bed volumes of eligible effluent (arsenic concentration≤0.01 mg·L^-1) were obtained in four As(III) adsorption cycles; while about 2000, 2300, 2500, and 3100 bed volumes of eligible effluent were obtained in four As(V) adsorption cycles. The dissection results of FMBO-diatomite fixed-bed exhibited that small amounts of manganese and iron were transferred from the top of the fixed-bed to the bottom of the fixed-bed during As(III) removal process. Compared to the extremely low concentration of iron (<0.01 mg·L^-1), the fluctuation concentration of Mn²⁺ in effluent of the As(III) removal column was in a range of 0.01–0.08 mg·L^-1. The release of manganese suggested that manganese oxides played an important role in As(III) oxidation. Determined with the US EPA toxicity characteristic leaching procedure (TCLP), the leaching risk of As(III) on exhausted FMBO-diatomite was lower than that of As(V).     

低温等离子体法处理甲醛气体

报道用低温等离子体的方法去除甲醛气体,主要考察了电场强度、进口浓度及填料对于甲醛气体去除效率的影响。实验研究结果表明,随着电场强度的增加,进口浓度的降低和在反应器中加有填料都会提高甲醛气体的去除效率。低温等离子体方法去除甲醛气体的机理可分为2部分:电子与污染物分子的直接碰撞和电场产生的活性粒子与污染物分子之间发生的一系列化学反应。     

常温下HAR处理低浓度生活污水中试启动

对有效容积为315L的复合式厌氧反应器(hybridanaerobicreactor,HAR)处理低浓度生活污水的启动情况做了研究,结果表明,HAR在常温下是可以启动的,复合式厌氧工艺在启动初期有利于厌氧污泥和有机物的积累。HAR的启动期可分为3个阶段,水温>15℃时,HAR运行34d后,反应器完成启动。水力停留时间(HRT)为6h,COD和SS去除率可达60%以上。容积负荷从0.775kgCOD/m3·d增加到2.227kgCOD/m3·d,去除效率不受影响。下部污泥床层和上部填料层的污泥特性不同,在启动期末,污泥床层有少量颗粒污泥出现。     

低温等离子体法去除苯和甲苯废气性能研究

对低温等离子体法去除苯和甲苯废气的性能进行了探讨,在理论分析的基础上进行实验研究。低温等离子体法去除苯和甲苯的机理是放电反应产生的高能电子与苯和甲苯分子发生非弹性碰撞并将能量全部或部分传递给目标分子,使其裂解、激化。被裂解、激化的分子与臭氧、活性基团发生一系列物理、化学反应后生成二氧化碳、一氧化碳和水。实验结果表明,苯和甲苯的去除率随着电场强度的增强而增大,随着气体流速的增大而减小。在较高电场强度下,有钛酸钡填料的反应器比无填料的反应器对苯和甲苯的去除率高得多,苯最高去除率可达92 6%,甲苯可达到96 8%。相同条件下甲苯比苯更容易去除。     

大气细颗粒物与糖尿病

随着我国社会经济和城市化的快速发展,大气颗粒物是影响我国城市空气质量的首要污染物,大气细颗粒物污染已严重威胁我国居民健康。本文简要综述了PM2.5诱导的氧化应激和炎症反应在糖尿病的发生和发展中的分子作用机制。     

猫儿山自然保护区森林群落垂直格局与主导因素分析

陆地生态系统中海拔高度的变化会导致植物群落的垂直性分布,这是形成植物多样性的一个重要性原因。了解和分析不同区域植物群落的垂直性分布规律和生物多样性形成机制对保护森林生物多样性具有重要意义。本文通过对猫儿山自然保护区不同海拔高度森林植物群落和环境因子的调查,运用双向指示种分析（Two-way Indicator-Species Analysis）和典范对应分析（Canonical Correspondence Analysis）,对不同海拔高度的群落进行划分,对决定植物群落分布的主导环境因子进行分析,结果表明：（1）猫儿自然保护区森林群落可以分为7个群落类型,其代表树种分别是罗浮栲Castanopsis fabri、栲树Castanopsis fargeisii、银木荷Schima argentea、铁椎栲Castanopsis lamontii、南方铁杉Tsuga chinensis、长苞铁杉Tsuga longibracterata、马尾松Pinus massoniana;（2）在中亚热带,海拔对山地植物群落形成起决定性作用;（3）土壤是仅次于海拔的重要环境因子,其中土类和土层厚度对森林群落的影响较大。在中亚热带森林生态保护和恢复过程中,按照不同海拔高度的植物群落特征选择种植合适树种,按照当地土壤条件选择适当的生态保护和恢复措施能加快生态恢复的进程,提高生态保护的效益。     

Decision Support System for emergency scheduling of raw water supply systems with multiple sources

A hydraulic model-based emergency scheduling Decision Support System (DSS) is designed to eliminate the impact of sudden contamination incidents occurring upstream in raw water supply systems with multiple sources. The DSS consists of four functional modules, including water quality prediction, system safety assessment, emergency strategy inference and scheduling optimization. The work flow of the DSS is as follows. First, the water quality variations on specific cross-sections are calculated given the pollution information. Next, a comprehensive evaluation on the safety of the current system is conducted using the outputs in the first module. This will assist in the assessment of whether the system is in danger of failure, taking both the impact of pollution and system capacity into account. If there is a severe impact of contamination on the reliability of the system, a fuzzy logic based inference module is employed to generate reasonable strategies including technical measures. Otherwise, a Genetic Algorithm (GA)-based optimization model will be used to find the least-cost scheduling plan. The proposed DSS has been applied to a coastal city in South China during a saline tide period as validation. Through scenario analysis, it is demonstrated that this DSS tool is instrumental in emergency scheduling for the water company to quickly and effectively respond to sudden contamination incidents.     

油田企业清洁生产审核实例

油田企业在为国家提供丰富石油资源的同时也成为环境污染的大户。自推行清洁生产以来,我国油田企业在清洁生产审核过程、节能降耗、环境保护等方面取得了较好成绩。以某油田企业为例,根据清洁生产＂节能、降耗、减污、增效＂的思路,以企业能源、资源利用情况的分析为基础,提出和实施了多项清洁生产方案。通过注气闸门填料改进、洗车用水回收再利用、化验室增加回收罐回收污油等方案的实施,同比可节电：20.74×104kW.h/a、节气：52×104m3/a、节水：2.80×104m3/a、减少污油排放：1.50 t/a左右,实现了经济效益和环境效益的双赢。