北京城市生态系统的能值动态分析

采用能值理论与分析方法,对北京市1990~2001年间的能值结构动态进行了分析,并采用人均能值、能值密度、生态功能潜力、人口基本承载力、能值自给率、能值货币比率、环境负载率、输入能值比等重要能值指标对该时期北京市城市生态系统的能值状况作了详细分析。研究表明,北京城市生态系统正处于较高发展水平,已基本跨入发达国家水平的行列;但高强度、快速发展给本市带来了巨大的生态环境压力,未来北京的可持续能力建设已势在必行。文章也提出了北京城市生态系统可持续发展能力建设的基本方向。     

无机阴离子对TiO2/SiO2光催化降解酸性红B活性的影响

以酸性红B为模型化合物，分别考察了6种常见的无机阴离子对TiO2/SiO2复合光催化剂活性的影响，并考察了导致催化剂失活的无机阴离子的最低浓度。结果表明，除了HCO3^-能引起催化剂部分不可逆中毒外，其余5种离子并没有在催化剂形成占位。失活的催化剂通过简的HCl冲洗即可再生。另外，对催化剂的失活机制作了初步探讨。     

The Relationship Between Exposure to Arsenic Concentrations in Drinking Water and the Development of Skin Lesions in Farmers from Inner Mongolia, China

Associations between the concentration of arsenic naturally occurring in drinking water and the development of skin lesions in people have been documented for some years at various locations around the world. Data on the exposure-response relationship between concentrations of arsenic in drinking water and prevalence of skin lesions in farmers from five locations in Inner Mongolia, China have been collected from the original publications and re-analysed together as a meta-study. The calculated data show a positive linear exposure-response relationship without a threshold. The reasons for this linear correlation are discussed and compared with the data from Xinjiang, another arsenism area located in a different geographical area of China. Here a different relationship was recorded that involved a threshold concentration before skin lesions developed. The significance of these two different exposure-response scenarios is discussed.     

广州城市生态环境变化

对广州城市生态环境因子的大气，水，固体废弃物和噪声污染状况近十年数据结合广州城市发展，分析其环境污染变化特征，结果表明，广州市大气环境污染已由煤烟型向石油型转变;环境中有机污染严重，主要表现为氨氮，BOD5，砷化物和汞化物污染，固体垃圾产出量逐年增加，声环境在逐步好转。     

白眉蝮蛇毒精氨酸酯酶的急性、亚急性毒性实验

用小鼠和大鼠分别研究了白眉蝮蛇(Agkistrodon halys ussuriensis )蛇毒中精氨酸酯酶的急性毒性和亚急性毒性.腹腔和静脉给药小鼠急性毒性分别为半数致死量LD50,ip =5.73～6.68 U/kg, LD50,iv=4.12～4.76 U/kg ;最大致死量LD100,ip=8.60 U/kg, LD100,iv=6.40 U/kg;最小致死量LDmin,ip =4.20 U/kg, LDmin,iv=3.10 U/kg .大鼠急性毒性结果分别为LD50,ip= 5.09～5.98 U/kg, LD50,iv=3.30～3.86 U/kg ; LD100,ip=7.80 U/kg, LD100,iv=5.50 U/kg; LDmin,ip=3.60 U/kg, LDmin,iv=2.70 U/kg.大鼠亚急性毒性实验结果为活动能力、生长率、进食量、死亡率等一般综合指标药物处理组和CK没有明显差别;血检、尿检等临床指标除谷丙转氨酶(GPT)高剂量药物处理组与CK有明显差异外(P<0.05),其它生化指标无显著差异(P>0.05);病理解剖和脏器系数指标,高剂量药物处理组肝脏明显肿大、空泡化,脏器系数也明显高于CK(P<0.05),其它脏器未见病变,脏器系数未见显著差异(P>0.05).从急性毒性和亚急性毒性方面考虑,纯精氨酸酯酶比现在临床应用的"蝮蛇清栓酶"(主要成分为精氨酸酯酶)毒性低. 表3 参11     

催化剂对甲醛废水湿式氧化的增效作用

在设定的湿式氧化条件下 ,从若干种金属盐中筛选了Cu(NO3) 2 作为氧化甲醛废水的催化剂 ,考察了Cu(NO3) 2 用量、废水的初始浓度及温度对有机物去除率的影响 ,结果表明 :Cu(NO3) 2 以 5mg·l- 1 Cu2 计量投加为宜 ,甲醛初始浓度在 480mg·l- 1 — 1 5 0 0mg·l- 1 范围内一直保持较高的去除率 ,反应的适宜温度为 1 40℃以上 ;根据反应过程数据建立了该催化氧化反应的分段一级动力学模型 ,求得甲醛氧化动力学模型快、慢步骤的表观活化能分别为7 2 9kJ·mol- 1 和 1 4 45kJ·mol- 1 ;而COD降解动力学模型快、慢步骤的表观活化能则分别为2 0 47kJ·mol- 1 和 2 9 5 2kJ·mol- 1 .     

A distributed-delay model to predict ageing and survival rates of adults of Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae) in granaries filled with wheat

A time-varying distributed-delay model simulating effects of multifactors was developed. Prediction of the ageing rate and survival distribution of adults of the rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae) in various environments found in wheat-filled granaries was conducted as an example to illustrate the application of this developed model. Published adult mortalities, determined at different temperatures, relative humidities, and food sources, were directly used to find the average ageing rate and family of cumulative function of adult mortality. The developed model could predict the adult survival rate at constant or transient temperatures with different relative humidities. This model could also simulate the effect of adult acclimation to their environment when they experience temperature and moisture fluctuations inside granaries. To validate the developed model, the simulation results were compared with available experimental data from the literature. There was no difference between predicted and measured mortalities in two granaries in which the mortalities were determined in a 4-month experiment.     

苗期玉米根叶对干旱胁迫的生理响应

采用人工控制水分的方法,研究了干旱胁迫下苗期玉米(ZeamaysL.)根系和叶片的生理指标,用以明确苗期玉米根系和叶片对干旱的生理响应。研究结果表明,苗期中度干旱胁迫处理条件下,玉米根系和叶片均表现出对干旱胁迫的生理响应,并各具特点。与对照相比,干旱胁迫使玉米根系和地上部的生物量降低,叶片中的叶绿素含量显著降低、叶片光合面积减小,根冠比增大。干旱胁迫使玉米根系比表面积增大,根系氧化活力和还原活力增强。干旱胁迫导致玉米叶片的光合功能降低,初始荧光升高,初始光系统Ⅱ(PSⅡ)的原初光能转换效率、PSⅡ潜在活性、潜在光合作用活力均受到抑制。干旱胁迫下玉米叶片和根系脂质过氧化作用增强,根系和叶片中的游离脯氨酸含量升高。     

介孔纳米TiO2的超声化学法合成及其表征

采用超声化学法制备介孔TiO2，并采用XRD，TEM，FT-IR等方法对样品进行了表征．结果表明，在超声波作用下，液相体系中能够一步合成锐钛矿相TiO2；添加有机模板剂并控制实验条件，则能直接合成具有介孔结构的锐钛矿相TiO2．超声化学法能更好地控制粒子的形貌和尺寸，所制备的TiO2晶型完整，孔径均匀，分散性好．     

耗散结构理论在土壤科学上应用途径的探索

本文根据耗散结构的基本理论，结合生产实践经验，提出了表征土壤肥力的非线性微分方程：＝（Ｋ－ｂ）ｘ－βｘ２Ｘ─土壤生物活性，ｔ─时间，Ｋ─生物繁殖系数，ｂ─生物死亡系数，β─生物饱和系数．解这个并不复杂的非线性微分方程，便可知道土壤是处于热力学分枝，还是耗散结构分枝．这对研究土壤肥力的动态变化、土壤肥力的分类、土壤的管理、土壤退化的防止等方面有着无法预测的应用前景．