水土化学体系中钙镁对土体结构强度贡献的试验研究

城市区域的土体环境一般是处在常态即常温、常压、缓变异的水化学环境中,在这种环境中,影响土体稳定的要素-土体中的化学组份扮演着重要的角色,而其对诸如地面沉降、土洞的产生都有重要影响。土体稳定受其结构强度控制,钙镁是土体结构构成中重要组成部分,理论与实践分析表明,在常态水环境下,其对结构往往起着控制作用,在常态水环境中,土结构的破裂面并不是通过颗粒本身,而是通过颗粒、颗粒集合体与集合体之间粒间连结。设计的常态水环境下的化学组份变异与CO2分压增高水环境下的室内模拟试验,揭示了化学组份钙镁对土体结构的贡献与对宏观强度的作用。     

二次颗粒物源成分谱的建立在尘源解析中的作用

通过CMB模型计算各类尘源对TSP、PM10的影响时发现,二次颗粒物对尘源解析起到了不容忽视的作用,因此就二次颗粒物源成分谱进行了专门解析研究,并把二次颗粒物解析也纳入到模型中来,从而完善了源解析结果。     

作物产量决定因子分析

应用主成分分析,将影响水稻产量的一系列因子概括为四个主要因子:(1)土壤肥力因子,(2)栽插措施因子,(3)田间管理因子;(4)产量性状因子。将上述因子作为自变量,水稻产量作为因变量,进行逐步回归分析,得到一个产量预测模型(R=0.962)。根据各变量的回归系数大小,可以得到产量决定因子对产量影响的大小顺序为,田间管理因子>土壤肥力因子。栽插措施因子和产量性状因子对水稻产量的影响未达显著水平。 文中所述的分析方法适用于在不同的土壤条件下预测作物产量的潜在变化。     

野化培训大熊猫在特定时期采食半枯竹的原因分析

对首次发现的一只野化培训大熊猫“祥祥”采食半枯竹的现象及原因进行研究.作者用4只圈养大熊猫为对照进行试验,从行为观察、营养成分及适口因子、环境气候条件等方面进行了研究.研究发现,圈养大熊猫中也存在采食半枯竹的现象,而且在采食的时间段上和祥祥一致;相对于新鲜竹子,半枯竹中葡萄糖含量有所增加,单宁含量明显降低,并且具有特殊的香甜味,使在一定时期内的半枯竹营养增加,适口性得到改善,这是大熊猫在特定时期更愿意采食半枯竹而不采食新鲜竹子的重要原因;7~9月是全年温湿度最高月份,对引起半枯竹成分中适口因子的改变可能有诱发作用.图3表4参9     

Natural pollution caused by the extremely acidic crater lake Kawah Ijen, East Java, Indonesia

Background. Aims and Scope Lakes developing in volcano craters can become highly acidic through the influx of volcanic gases, yielding one of the chemically most extreme natural environments on earth. The Kawah Ijen crater lake in East Java (Indonesia) has a pH 〈 0.3. It is the source of the extremely acid and metal-polluted river Banyupahit (45 km). The lake has a significant impact on the river ecosystem as well as on a densely populated area downstream, where agricultural fields are irrigated with water with a pH between 2.5 and 3.5. The chemistry of the river water seemed to have changed over the past decade and the negative effect in the irrigation area increased. A multidisciplinary approach was used to investigate the altered situation and to get insight in the water chemistry and the hydrological processes influencing these alterations. Moreover, a first investigation of the effects of the low pH on ecosystem health and human health was performed. Methods Water samples were taken at different sites along the river and in the irrigation area. Sampling for macroinvertebrates was performed at the same sites. Samples of soil and crop were taken in the irrigation area. All samples were analysed for metals (using ICP-AES) and other elements, and concentrations were compared to local and international standards. Results and Discussion The river carries a very high load of SO4, NH4, PO4, Cl, F, Fe, Cu, Pb, Zn, Al and other potentially toxic elements. Precipitation and discharge data over the period of 1980 – 2000 clearly show that the precipitation on the Ijen plateau influences water chemistry of the downstream river. Metal concentrations in the river water exceed the concentrations mentioned in Indonesian and international quality guidelines, even in the downstream river and the irrigation area. Some metal concentrations are extremely high, especially iron (up to 1600 mg/l) and aluminium (up to 3000 mg/l). The food-webs in the acidic parts of the river are highly underdeveloped. No invertebrates were present in the extremely acid water and, at pH 2.3, only chironomids were found. This also holds true for the river water with pH 3.3 in the downstream area. Agricultural soils in the irrigation area have a pH of 3.9 compared to a pH of 7.0 for soils irrigated with neutral water. Decreased yields of cultivated crops are probably caused by the use of Al containing acid irrigation water. Increased levels of metals (especially Cd, Co, Ni and Mn) are found in different foodstuffs, but still remain within acceptable ranges. Considering local residents” diets, Cd levels may lead to an increased risk for the human health. Fluoride exposure is of highest concern, with levels in drinking water exceeding guideline values and a lot of local residents suffering from dental fluorosis. Conclusions, Recommendations and Outlook In short, our data indicate that the Ijen crater lake presents a serious threat to the environment as well as human health and agricultural production.     

低氨氮、低碱度废水的亚硝化研究

通过实验室血清瓶培养试验，研究了pH、碱度、FA、FN、HRT等因素对低氨氮、低碱度废水亚硝化过程的影响。研究结果表明：出水的pH值可以通过控制反应器内部的碱度来进行调节。控制进水碱度在113．1～269．7mg／L，HRT为48h，其亚硝酸累积率可达到67．15％。在氨氮亚硝化过程的同时，有部分有机氮也在向亚硝酸盐进行转化。通过污泥亚硝化驯化过程，游离氨对亚硝化单胞菌抑制浓度的临界值可以达到0．96mg／L。     

水溶液中腐殖酸和苯酚在ZH-02树脂上的双组分吸附

通过苯甲酰基修饰的苯乙烯-二乙烯苯吸附树脂ZH-02对水中腐殖酸和苯酚进行了单组分和双组分的静态吸附.结果表明,在腐殖酸为主要吸附质的二元组分溶液中,对苯酚的吸附量的影响可以利用IAST模型进行预测;而在不存在主要吸附质的二元溶液中,可以用单组分体系的平衡吸附量近似预算双组分竞争体系时各组分的平衡吸附量.     

一种新型复合球填料在低浓度污再生回用中的应用研究

新型复合球填料为沸石与悬浮球填料的有机组合体，密度约为0．92～0．97g／cm^3，比表面积为711～1185m^2/m^2，表面粗糙，物化性能稳定。在曝气量为20：1，停留时间为6h时，装有新型复合球填料的反应柱挂膜容易，成膜时间短，膜不易脱落，且生物相丰富。膜成熟时对生活污水中的氨氮和COD都有很好的去除效果，出水氨氮浓度≤2mg／L，去除率≥93％；出水COD浓度≤22mg／L，去除率≥80％。新型复合球反应柱在稳定状态处理低浓度的二级出水时，出水氨氮浓度≤2mg／L，去除率89％，出水COD浓度为10～36mg／L，去除率为48％～81％。出水水质符合GB50335-2002标准。     

Photolytic degradation of fluoroquinolone carboxylic acids in aqueous solution

Subsequent to irradiation with a xenon lamp simulating sunlight, fluoroquinolone carboxylic acids in aqueous solution form polar pyridone dicarboxylic and tricarboxylic acids. After liquid/liquid partition with chloroform/water these substances can be isolated by ion exchange chromatography of the aqueous phase. They can be regarded as intermediate compounds on the route to a complete photomineralization. The structural elucidation is performed by such mass spectroscopic methods as MS, GC/MS and HPLC/MS, whereby HPLC/MS shows the highest reliability. Additionally¹H- and¹³C-NMR measurements confirm the structure of the main polar degradation product.     

外来入侵杂草空心莲子草对植物生物多样性的影响

利用样方法调查了南京市空心莲子草(Alternantheraphiloxeroides)生长生境中杂草的种类和分布。结果表明,南京市秋季空心莲子草分布样点有杂草30科101种,其中以禾本科、菊科、蓼科居多。主成分分析表明,影响杂草分布的主要因素是土壤水分条件和人为干扰强度。经Q型分析, 24个样点可划分为3个聚类群:聚类群Ⅰ包括的样点均分布在路边和田边开阔地以及小河、小沟和湖的岸边,以马唐、狗尾草和牛筋草为优势种;聚类群Ⅱ的样点都是农田隔离带如田埂以及农田中的沟壑,以波斯婆婆纳、碎米莎草、野塘蒿和铁苋菜为优势种;聚类群Ⅲ的样点以菜地和果园为主,以马唐、香附子、马齿苋和黄鹌菜为优势种。分析了空心莲子草重要值与物种丰富度之间的关系,当空心莲子草重要值大于1. 5时,样方物种丰富度随重要值的增加而减小。2者之间具有显著相关性,表明空心莲子草的入侵对生物多样性有不利影响。