绿色阻垢剂聚天冬氨酸的液相优化制备

在分析国外多种合成聚天冬氨酸(PASP)的方法的基础上,采用马来酸酐与氨水进行溶液聚合的方法制备聚天冬氨酸,并对产物的阻垢率、黏均相对分子质量、生物降解性等性能指标进行了评价.采用静态阻垢法评价产物的阻垢率;采用极限黏度法测定聚琥珀酰亚氨的聚合度,然后计算PASP的黏均相对分子质量;采用摇床法通过对比降解前后的COD检测PASP的生物降解性能.同时,根据性能指标的变化分别对原料的物质的量配比、聚合温度和聚合时间进行了单一条件的筛选.经实验确定的合成PASP的最佳条件是:原料物质的量配比1∶1.1,聚合温度160℃,聚合时间1 h.在此条件下合成的PASP阻垢率超过95%,生物降解性能达到70%.     

基于熵权的改进密切值法在地面水水质评价中的应用

为了简化传统密切值法运算,更能全面客观地反映出各样本的优劣情况,尝试采用目标差值率法进行初始矩阵的规范化处理,引入熵权法确定各评价指标的权重,对传统密切值法进行了改进.通过将两种不同密切值法对某区域水体水质的评价结果进行对比表明: 两种密切值法评价水质得出了一致的水质优劣排序,但改进后的密切值法可以有效地消除各评价指标在量纲、数量级及指标优劣等方面的差异,计算更简便; 改进后的密切值法利用熵权法确定各评价指标的权重,更客观; 改进后的密切值法评价结果中各样本的差异性放大了,对比更为明显.     

长三角典型区土壤重金属有效态的协同区域化分析、空间相关分析与空间主成分分析

以昆山市为典型区,采集了126个表层土壤样品,通过多元统计学、地统计学与GIS技术相结合,采用基于协同区域化理论的因子克立格法探讨了长三角多个土壤重金属有效态的区域分异,并在剖析不同空间尺度有效态重金属的空间结构特征基础上,应用空间相关分析和空间主成分分析来揭示引起这种分布格局的成因和污染来源,结果表明,昆山土壤有效态重金属服从正态或对数正态分布,变异系数较大,有效态Cd污染最重.重金属有效态在空间上可划分为块金尺度、小空间尺度（15 km左右）和大空间尺度（40 km左右）,它可用3个尺度的实验（交叉）变异函数的协同区域化模型线性拟合.空间相关分析中,Cd和Zn在3个尺度中的相关性均极显著,且元素在小尺度和大尺度的相关性比块金尺度更强,大尺度的负相关特征较其它尺度明显.空间主成分分析表明,不同尺度的空间污染来源不同.重金属有效态第一、二主成分的空间分布格局结果表明重金属有效态含量与工业活动、污水灌溉和土壤性质密切相关.     

Assessing field vulnerability to phosphorus loss in Beijing agricultural area using Revised Field Phosphorus Ranking Scheme

Guanting Reservoir,one of the drinking water supply sources of Beijing,suffers from water eutrophication.It is mainly supplied by Guishui River.Thus,to investigate the reasons of phosphorus(P)loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region.In this study,a Revised Field P Ranking Scheme(PRS)was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS.In this new scheme,six factors are included, and each one was assigned a relative weight and a determination method.The affecting factors were classified into transport factors and source factors,and,the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme.By the new scheme,thirty-four fields in the Guishui River were categorized as"low","medium"or"high"potential for P loss into the runoff.The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields.The source factors were the main factors to affect P loss from the study area.In the study area,controlling P input and improving P usage efficiency are critical to decrease P loss.Based on the results,it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of E Compared with P surplus by field measurements,the Revised Field PRS was more suitable for reflecting the characteristics of fields,and had higher potential capacity to identify critical source areas of P loss than PRS.     

Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain, Northeast China

Overwhelming evidence reveals that concentrations of dissolved organic carbon （DOC） have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0-10 cm and 10-20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland （R^2 = 0.3122 and R^2 = 0.443）. The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions. The concentrations of total organic carbon （TOC）, total carbon （TC） and Fe（II）, DOC mobility and continuous vertical and lateral flow affectext the distribution variations of DOC in soil-water solutions. The correlation coefficients between DOC concentrations and TOC, TC and Fe（II） were 0.974, 0.813 and 0.753 respectively. These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the Sanjiang Plain.     

1957-2007年新疆天山山区气候变化对径流的影响

利用天山山区1957-2007年的气温、降水量及径流数据,借助非参数检验、小波变换等方法分析了天山山区气温、降水量及年径流量的变化趋势及多时间尺度相关。结果表明:玛纳斯河与塔里木河源流区年径流量、气温与降水量均呈显著增加趋势;在年代际上,塔里木河源流区气温存在11、18和22 a的主周期,降水量存在10、20与22 a的主周期;玛纳斯河气温在10与22 a处存在明显周期,降水量在20与22 a处周期性明显;同时,两源流区气温和降水量皆存在3~6 a的年际周期变化;塔里木河年径流量、气温和降水量的突变点分别发生在1993、1993和1992年,而玛纳斯河分别在1995、1988与1996年发生显著性突变;两流域源流区年径流量与气候因子存在显著的多时间尺度相关关系。     

国内外土地利用区划研究的回顾与展望

土地利用区划是从区域角度观察和研究地域综合体,探讨土地利用的发展历史、现状特点、变化过程及趋势,从最大限度发挥土地生产潜力及改善土地生态系统的结构与功能出发,对土地的合理利用方向,包括确定国民经济各部门用地的合理分配、结构和布局形式等,在地域上进行分区。通过简要回顾国内外土地利用区划研究的发展历程,总结了土地利用区划研究的理论方法特点及存在的问题,并在此基础上探讨今后土地利用区划研究的重点及发展方向：从自然要素向自然与人文要素有机结合方向转变;从大空间尺度向多空间尺度方向转变;从传统的区划方法向综合集成的新技术手段转变;从静态的区划研究向多要素、多过程耦合的动态区划研究方向转变。     

SIMULATION OF HERBICIDE CONCENTRATIONS IN STORMFLOW FROM FORESTED WATERSHEDS1

The breakpoint rainfall hydrology and pesticide options of the field scale model CREAMS (Chemicals, Runoff, and Erosion from Agricultural Management Systems) were used to predict average concentrations of hexazinone [3 cyclohexyl-6-(dimethyl-amino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] in stormflow from four forested watersheds in the upper Piedmont region of Georgia. Predicted concentrations were compared with measured concentrations recorded over a 13-month period. CREAMS accurately predicted hexazinone concetrations in the initial stormflow events which also contained the highest concentrations. The model underestimated the hexazinone concentrations in stormflow two months and greater following pesticide application. In a companion study, the daily rainfall option of the CREAMS model was used to evaluate the reltive risk associated with the maximum expected concentration of hexazinone, bromacil (5-bromo-3 sec-butyl-6 methyuracil), picloram (4-amino-3,5,6 trichloropicolinic acid), dicamba (3,6-dichloro-0-anisic acid), and triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} in stormflow from small forested watersheds. The model predicted the following order of potential residue appearance in stormflow: bromacil>triclopyr>hexazinone>picloram>dicamba. Subsurface movement of residues via interflow and deep leaching losses are not simulated by the version of CREAMS used in these studies.     

Results from Three Field Tracer Experiments on the Neighbourhood Scale in the City of Birmingham UK

The physical processes governing flow and pollutantdispersion at the neighbourhood scale, a spatial scaleintermediate between the street scale and the city scale, is notwell understood. Furthermore, it is not clear whether a traditional approach using averaged characteristics such as theaerodynamic roughness length is sufficient to predict the concentration field at this scale. To investigate pollutant dispersion in a real urban area, three field experiments were designed within the UK-URGENT programme sponsored by NERC. Theexperiments were performed in the City of Birmingham using a finite duration release of inert, non-toxic and non-depositingtracers, vis. perfluoromethylcyclohexane (PMCH) and perfluoromethylcyclopentane (PMCP). Measurements were taken using air bag samplers placedin an arc at 3.5 km (first experiment) and 1 km (second andthird experiments) from the source; some trap samplers wereplaced outside the main arc in the outskirts of the city. Measurements were analysed in the laboratory using anovel gas-chromatography technique. Data so obtained werecompared with predictions from a simple steady-state modeland a time-dependent model. The concentration-time serieswere very asymmetrical with a sharp rise, a plateau followedby a relatively slow decrease and finally a long-livedplateau above (or possibly very slow decrease to) thebackground level.     

可持续发展中合理人口规模的研究：以苏南地区集镇为例

本文在分析农业人口转移数量、经济效益、社会商品销售额、集镇容纳能力的基础上,研究了集镇合理人口规模的界线。