N-甲基咪唑配体络合金属Cu(Ⅰ)催化剂对水中2,4-二甲氧基溴苯还原脱溴

合成了以N-甲基咪唑为配体,Cu为活性中心的络合金属多相催化剂Cu(Ⅰ)-NHC-SBA-15.通过1H-NMR、13C-NMR、有机元素分析和FTIR对各步合成反应产物结构经行了鉴定;用SEM、N2吸附脱附等方法对催化剂进行了表征;用ICP测定了催化剂Cu含量.对催化剂催化2,4-二甲氧基溴苯还原脱溴活性进行了测试.在反应时间为24 h,通过正交实验和单因素实验,考察了催化剂用量、反应温度、还原剂用量等因素对脱溴率的影响,并确定了最佳反应条件:催化剂用量为0.05 g、水合肼用量为2 mL、反应温度为80℃,脱溴效果较好,脱溴率达到98.5％.对催化剂重复使用进行了初步研究.对催化反应动力学进行了初步研究,结果表明,该多相催化反应是由表面反应速度控制,并符合一级动力学反应.对反应机理进行了初步探讨.     

Application of Wavelet Coherence Method to Investigate Karst Spring Discharge Response to Climate Teleconnection Patterns

The impact of climate teleconnections on the regional hydrometeorology has been well studied, but very little effort has been made to relate climate teleconnections with groundwater flow variation. In this study, we used a wavelet coherence method to analyze monthly climate indices, precipitation, and spring discharge data, and investigated the relation between major teleconnection patterns (the Arctic Oscillation, North Atlantic Oscillation, Pacific Decadal Oscillation, El Niño‐Southern Oscillation, and Indian Ocean Dipole) and karst hydrological process in Niangziguan Springs Basin, China. The results indicate precipitation and spring discharges correlate well with climate indices at intra‐ and inter‐annual time scales. Further, the climate indices are mainly correlated with precipitation at shorter periodicities, but correlated with spring discharge at longer scales. The difference reflects the modulation of karst aquifers on precipitation‐spring discharge during the processes of precipitation infiltration into the ground, and subsequent transformation into spring discharge. When teleconnection signals are transmitted into spring discharge via precipitation infiltration and groundwater propagation, some high‐frequency climatic signals are likely to be filtered, attenuated, and delayed, thus only low‐frequency climatic signals are preserved in spring discharge.     

Endogenous <Emphasis Type="Italic">trans</Emphasis>-zeatin content in plants with different metal-accumulating ability: a field survey

A field survey was conducted to evaluate soil metal pollution and endogenous trans-zeatin content in the leaves of plants growing at six sites in a metal-polluted area located in Gejiu, Yunnan, China. Five plant species were collected, and the physicochemical properties and concentrations of five metals in the soil were analyzed. The trans-zeatin content in plant leaves was measured by high-performance liquid chromatography. Based on the Nemerow pollution index, the six sites were classified into four levels of pollution (i.e., low, medium, high, and severely high). The degree of soil metal pollution was cadmium (Cd) > arsenic (As) > lead (Pb) > zinc (Zn) > copper (Cu). The leaf trans-zeatin content in Pteris vittata (an arsenic hyperaccumulator) increased significantly by 98.6 % in soil with a severely high level of pollution compared with soil at a low level of pollution. However, in non-hyperaccumulators Bidens pilosa var. radiata and Ageratina adenophora, a significant decrease in leaf trans-zeatin content of 35.6 and 87.6 %, respectively, was observed. The leaf trans-zeatin content in Artemisia argyi also decreased significantly by 73.6 % in high metal-polluted soil compared with that in medium metal-polluted soil. Furthermore, significant correlations were observed between leaf trans-zeatin content in Pteris vittata and As, Pb, and Cd concentrations in the soil; however, either no correlation or a negative one was observed in the other plant species. Therefore, a high content of trans-zeatin in the leaves of Pteris vittata may play an important role in its normal growth and tolerance to metals.     

Fenton氧化法深度处理甲醛废水

采用Fenton氧化法深度处理经生化降解后的甲醛废水,结果表明,Fenton氧化法深度处理甲醛废水是可行的,在合适的反应条件下,降解初始COD为150 mg/L左右的甲醛废水,COD去除率达30%以上;Fe2+与H2O2的投加比例、投加量及投加方式、反应温度、pH、反应时间对处理效果都有不同程度的影响。     

Evaluating Phosphorus Loss for Watershed Management: Integrating a Weighting Scheme of Watershed Heterogeneity into Export Coefficient Model

The identification of critical source areas (CSAs) and critical source periods (CSPs) are essential prerequisites for cost-effective practices of non-point source (NPS) pollution control. A simple empirical tool combining Export Coefficient Model (ECM) and a Geographic Information Systems (GIS)-based weighting scheme of watershed heterogeneity was proposed to estimate annual and monthly phosphorus loss, to identify critical source areas and periods, and to assess pollution control practices. The GIS-based weighting scheme was developed to represent the transport potential of runoff to move phosphorus from the land surfaces to waters, as a supplement to the source-based ECM. The empirical tool was applied to the Dianchi Lake watershed of China. The results showed that the total phosphorus loss from NPS in 2008 was 352.3 tons. The agricultural land was recognized as the largest and the most spatially various source type. The lakeside plain and the terraces of the watershed were identified as CSAs, which generated more than 90 % of non-point phosphorus. The early part of wet season (from May to August) was the CSPs, when about 70 % of non-point phosphorus was lost. The reduction of phosphorus fertilizers and the vegetated buffer strips (VBS) were effective in controlling phosphorus loss from NPS in the watershed. A reduction of 20 % in phosphorus fertilizer application combined with the set-up of VBS in both riparian area of the main watercourses and the lakeside areas would decrease 25 % of phosphorus loss.     

常规与深度处理工艺对长江下游浅库型原水的处理效果比较研究

基于长江下游浅库型原水,对比常规与深度处理工艺运行效果,探索溶解性有机物(DOM)分子量分布的变化及其与消毒副产物生成的联系,明确常规与深度处理工艺的工艺适应性。研究结果表明,长江下游浅库型原水经以臭氧-生物活性炭(O3-BAC)为核心的深度处理后,出水高锰酸盐指数(IMn)、溶解性有机碳(DOC)、254nm单位吸光度(UV254)、UV254与DOC比值(SUVA254)、三卤甲烷生成潜能(THMFP)和卤乙酸生成潜能(HAAFP)分别降低了33%～79%、41%～67%、60%～81%、24%～58%、37%～70%和35%～64%,且出水小分子DOM(分子量≤1ku)占比降至50%(质量分数)以下。常规处理工艺中,混凝、沉淀及砂滤是DOM的主要去除单元;而深度处理工艺中,DOM则主要靠O3-BAC去除。针对长江下游浅库型原水,以O3-BAC为核心的深度处理工艺具有更高的工艺适应性,并能实现对DOM的有效去除。     

低温环境下桥梁用结构钢疲劳寿命估算方法

在现有研究成果的基础上,基于断裂力学理论提出了适用于桥梁结构钢的低温疲劳寿命估算方法。利用室温环境下的疲劳性能参数和低温环境的基本力学性能参数对低温环境下的疲劳极限、疲劳裂纹扩展门槛值等进行预测,建立疲劳裂纹扩展速率模型,应用等效初始裂纹法估算低温环境下桥梁钢的疲劳寿命,并通过塑性区裂纹尺寸修正进行低周疲劳寿命预测。通过算例表明,该方法能够较为准确的预测Q345qD钢试件的拉伸疲劳寿命,从而避免了成本高昂的低温疲劳试验,为钢结构桥梁的低温疲劳分析提供简便而实用的依据。     

冬季沈阳市典型源排放PM_(10)浓度分布模拟分析

选取沈阳市7个典型的大气污染源2006年12月~2007年2月的PM10排放浓度资料,利用CALPUFF对PM10浓度月平均分布做模拟分析。模拟结果分析表明:冬季月平均PM10浓度分布的范围与风场、地形有直接的关系。地势平坦、风速大时,污染物扩散范围大,污染物浓度小;地势不平、风速小时,污染物扩散范围小,污染物浓度大。1月份是沈阳市冬季月平均大气污染最严重的月份,污染物分布主要集中在市区的北部、东部和南部地区,东部地区大气污染最为严重。     

辽宁省区域性空气污染的天气分型

应用2003-2004年主要污染物浓度和气象资料,对辽宁省全年的PM10产生的区域性3级空气污染进行环流分型,按污染源划分为冬季煤烟型、春季沙尘型和夏秋大雾型.其中冬季煤烟型又分为长白山高压地形槽型、高压内部均压场型、东北高压脊,西部倒槽型、蒙古高压前均压场、蒙古低压前均压场、高压内部小范围均压场型6个型;春季沙尘型分为东北低压型、南大风型和干冷锋北大风型;夏秋大雾型分为低压槽型和低压前均压场.上述类型几乎概括了近两年PM10 3级污染的所有个例,为大气环境质量预报、总量控制等提供依据.