区域REE系统的构建及其综合评价

从区域可持续发展的角度出发,提出了区域资源环境经济(REE)系统的概念,初步对区域REE系统的研究对象、系统结构进行了探讨,建立了区域REE系统可持续运行的评价指标体系,并通过实例研究论证了它对区域可持续发展的基础性和指导作用,以及评价指标体系的可用性.     

Rapid amino acid cycling in arctic and antarctic soils

Amino acids constitute one of the largest inputs of organic nitrogen (N) to most polar soils and have been hypothesized to be important in regulating vegetational succession and productivity in Arctic ecosystems. Our understanding of amino acid cycling in these soils, however, is poor. The aim of this study was to investigate the size and rate of turnover of the amino acid pool in a range of Arctic and Antarctic soils. Our results indicate that in polar soils with either high or low ornithogenic inputs the amino acid pool is small in comparison to the inorganic N pool (NO^–₃ and NH⁺₄). The free amino acid pool constituted only a small proportion of the total dissolved organic nitrogen (DON) pool in these soils. Here we show that these low concentrations may be due to rapid use by the soil microbial community in both Arctic and Antarctic soils. The turnover of the amino acid pool in soil was extremely rapid, with a half-life ranging from 2 to 24 h, indicating that this N pool can be turned over many hundred times each summer when polar soils are frequently unfrozen. The implications of amino acids in N cycling and plant and microbial nutrition are discussed.     

Impact of Land Use on Soluble Organic Nitrogen in Soil

Although it has been hypothesized that soluble organic nitrogen (SON) plays a central role in regulating productivity in some terrestrial ecosystems, the factors controlling the size of the SON pool in soil remain poorly understood. Therefore our principal aim in this work was to assess the impact of seven different land use systems (rough and managed grassland, deciduous and coniferous woodland, heathland, wetland and tilled land) on the size of the SON and inorganic N (NO ₃ ^– , NH ₄ ⁺ ) pools in the surface soil layer (0–15 cm). After extraction with deionised water, we found that in most cases the size of the water extractable organic N (WEON) pool was similar in size to the inorganic N pool. In contrast, the KCl extractable organic N (KClEON) pool constituted the dominant form of soluble N in soils under all land uses, perhaps indicating that significant amounts were held on the soil exchange phase. In contrast to inorganic N, which varied significantly with land use, the size of the KClEON and WEON pool was similar for all land uses with the exception of KClEON in tilled land, where significantly lower amounts were observed. We conclude that SON constitutes an important soil N pool in a broad range of land uses, and that its role in microbial N assimilation, plant nutrition and ecosystem responses to atmospheric N deposition warrants further attention. SAFRD, University of Newcastle, Newcastle-upon-Tyne, NE1 7RU, U.K.     

Polymeric Complexes from Casein and Starch Phosphate: Characteristics and Enzyme Susceptibility

Novel biodegradable materials were prepared from potato starch enriched in phosphato moieties (DS 0.018 and 0.033) and casein in defatted milk. The components were blended in proportions providing starch: casein ratios of 2:1, 1:1, and 1:2 and were then precipitated with hydrochloric acid. Aqueous solubility, water-binding capacity, infrared spectra, and thermal analysis (thermogravimetry[7] and differential thermogravimetry of the precipitates revealed that they were not simple physical mixtures of the components. The components interacted with one another electrostatically with involvement of the phosphate groups of starch and the peptide bond of casein, as documented by infrared spectra. Because of insolubility in 7 M aqueous urea solution, they might also be considered as complexes in which the components were chemically bound.     

Mechanical and Barrier Properties of Biodegradable Films Made from Chitosan and Poly (Lactic Acid) Blends

Biodegradable film blends of chitosan with poly(lactic acid) (PLA) were prepared by solution mixing and film casting. The main goal of these blends is to improve the water vapor barrier of chitosan by blending it with a hydrophobic biodegradable polymer from renewable resources. Mechanical properties of obtained films were assessed by tensile test. Thermal properties, water barrier properties, and water sensitivity were studied by differential scanning calorimeter analysis, water vapor permeability measurements, and surface-angle contact tests, respectively. The incorporation of PLA to chitosan improved the water barrier properties and decreased the water sensitivity of chitosan film. However, the tensile strength and elastic modulus of chitosan decreased with the addition of PLA. Mechanical and thermal properties revealed that chitosan and PLA blends are incompatible, consistent with the results of Fourier transform infrared (FTIR) analysis that showed the absence of specific interaction between chitosan and PLA.     

Lightweight Concrete Containing an Alkaline Resistant Starch-Based Aquagel

Starch aquagel-based lightweight concrete has properties similar to those of other lightweight concrete products. However, starch aquagels are unstable in the strongly alkaline conditions typical of Portland Cement-based concrete and may interfere with the setting process. The effect of alkali treatments on the physical, mechanical, and functional properties of starch aquagels and aquagels from starch/polymer blends was investigated. Starch was blended at 100–115°C in a twin-screw extruder with five different polymers to determine whether the blends improved alkaline resistance. Polymer blends containing 5%, 15%, and 30% of the polymer hydrated and formed aquagels when equilibrated in water for 24 h. However, equilibrium moisture content was lower for the blends compared to the starch control. Aquagels equilibrated in 0.15 N NaOH swelled, lost compressive strength and had greater than 90% moisture. The blend of starch and 30% PVOH absorbed less moisture and was more resistant to alkaline dissolution in 1 N NaOH than the other blends tested making it a more suitable material for aquagel-based concrete. The moisture content of starch-based aquagels and mixing time were critical factors in determining setting times. The size of aquagel blends had a minor effect on density and compressive strength.     

除湿机的冷凝水化学成分与空气环境质量的关系

本文采用家用除湿机作为空气水溶性物质采样器方法，并验证了该方法作为空气水溶性物质采样嚣的可行性。本文通过空气冷凝水化学成分与空气总悬浮微粒(TSP)可溶性化学成分的对比，得到水汽中大部分阴阳离子的含量只比TSP低1个数量级，而水汽中的微量元素含量与各种碳的浓度不都比TSP低，TSP中一般检测不出亚硝酸根，而水汽中则检出大量亚硝酸根。     

南充市空气中可吸入颗粒物污染水平分析

本文在连续1年又5个月同步采样的基础上，测得南充市市辖三城区5个采样监测点环境空气中PM10的浓度及其时空变化进行了分析。结果表明，PM10的日平均浓度范围为0．020～1．030mg／m^3，超标率达38．0％；周日均浓度在0.040～0．520mg／m^3之间，超标率达到了37．8％。空气污染最重为嘉陵城区，其次为高坪城区，再次为石油学院、炼油厂和市府二院。浓度季节变化特征表现为冬季最高，其次为秋季，再次为春季，最轻为夏季。     

层次分析法在工业园区生态影响评价中的应用--攀枝花市高耗能工业园区生态环境影响探讨

目前生态影响评价研究中的评价对象、内容和方法缺乏统一的模式，本文以攀枝花高耗能园区的开发为例，尝试建立一套系统的工业园区开发生态影响评价方法，该方法以层次分析法为基础，将生态系统分解为经济发展、社会进步、环境保护、景观生态保护四个目标子系统，并在此基础上细化评价因子，通过专家打分和矩阵运算确定其权重，再根据适当的评价标准，运用指数法得出评价结果。结果表明该工业园区在建成前后，其生态综合指数由0．552提高到0．794．其级别由三级提高到二级，说明该园区生态系统总的状态得到改善，该工业园区项目开发可行。     

改进型石灰混凝法去除城市污水二级出水中有机物的研究

将石灰混凝处理后的沉淀泥渣进行回流，对石灰混凝法进行改进，研究改进后的石灰混凝法对城市污水二级出水中有机物的去除效果。结果表明，活性泥渣回流有利于提高石灰混凝法对城市污水二级出水中有机物的去除。回流位置在石灰投加前、复合絮凝剂投加后，最佳回流量为新泥渣产生量的100％～200％，活性泥渣回流的最佳pH为11．0～11．5；活性泥渣中CaCO3、Mg(OH)2、Fe(OH)3等沉淀物以及有机高分子絮体均有助于提高其对有机物的去除效果，其中Mg(OH)2沉淀物起主导作用；含循环泥渣的活性污泥回流，对有机物的去除效果无明显影响。