Subtropical urban turfs: Carbon and nitrogen pools and the role of enzyme activity

Urban grasslands not only provide a recreational venue for urban residents, but also sequester organic carbon in vegetation and soils through photosynthesis, and release carbon dioxide through respiration, which largely contribute to carbon storage and fluxes at regional and global scales. We investigated organic carbon and nitrogen pools in subtropical turfs and found that dissolved organic carbon(DOC) and dissolved organic nitrogen(DON)were regulated by several factors including microbial activity which is indicated by soil enzymatic activity. We observed a vertical variation and different temporal patterns in both soil DOC, DON and enzyme activities, which decreased significantly with increasing soil depths. We further found that concentration of soil DON was linked with turf age. There were correlations between grass biomass and soil properties, and soil enzyme activities. In particular, soil bulk density was significantly correlated with soil moisture and soil organic carbon(SOC). In addition, DOC correlated significantly with DON. Significant negative correlations were also observed between soil total dissolved nitrogen(TDN) and grass biomass of Axonopus compressus and Zoysia matrella. Specifically, grass biomass was significantly correlated with the soil activity of urease and β-glucosidase. Soil NO3-N concentration also showed negative correlations with the activity of both β-glucosidase and protease but there were no significant correlations between cellulase and soil properties or grass biomass. Our study demonstrated a relationship between soil C and N dynamics and soil enzymes that could be modulated to enhance SOC pools through management and maintenance practices.     

邻硝基苯基荧光酮与铝显色反应的研究及其应用

研究了在溴化十六烷基吡啶存在下，邻硝基苯基荧光酮与铝显色反应的条件，结果表明，在ｐＨ５．０的乙酸－乙酸钠缓冲溶液中，Ａ１（Ⅲ）与邻硝基苯基荧光酮生成一种玫瑰红色给合物，其最大吸收波长在５５９ｎｍ，摩尔吸光系数为７．８２×１０４，比耳定律范围０～１０μｇ／２５ｍｌ，拟定了测定饮茶、饮水中微量铝的方法，结果令人满意。     

实用型深度光氧化设备对几种染料和多菌灵农药废水的处理

利用HFS 1型深度光氧化废水处理设备对活性艳蓝K3R、酸性红 3B、活性黑KNB、酸性红A、直接耐酸大红4BS等 5种染料的水溶液和多菌灵农药废水进行了深度光氧化处理。结果表明 :(1)染料在处理 5min后 ,脱色率都在 90 %以上 ;处理 15min后 ,CODCr的去除率除活性艳蓝K3R较低外 ,其余的都在 80 %以上 ;BOD5/CODCr的值都有所增大。 (2 )多菌灵农药废水 (经稀释 )处理 4 0min后CODCr的去除率为 5 7.0 % ,BOD5/CODCr的值由 0 .2 0增加到 0 .4 4。 (3)采用深度光氧化 -絮凝的工艺处理多菌灵农药废水 ,CODCr的去除率为 5 7.5 %。     

中国古代生态安全与可持续发展

中国自然生态优越但脆弱。农业历史悠久,但盲目扩大农耕造成生态破坏,威胁生态安全与可持续发展。由于中国古代农牧业分区发展,农耕灌溉施肥,精耕细作,保护了土地资源。农业中心由黄河流域逐步迁移到长江流域,维持了可持续发展,但经验教训十分深刻。     

中荷水处理示范研究培训中心的工作领域与思路

中荷水处理示范研究培训中心是中荷合作的产物,今后将对中国各城市污水处理技术人员、高校师生等进行培训,为建设和管理污水处理厂提供技术咨询,开展污水处理新技术的开发与推广,并开展对内对外的合作与交流。     

高岭土制备聚合氯化铝新工艺

介绍了以高岭土为原料，经盐酸预处理后，加水聚合、调整反应液pH，制备液体聚合氯化铝净水剂的新工艺。对所得产品的净水性能和技术指标进行了测定，结果表明，采用该工艺制得的聚合氯化铝产品技术指标符合GB1592－95标准。     

基于顶板离层监测的锚固巷道稳定性控制

在提出顶板离层概念的基础上 ,对顶板离层与锚固系统的变形协调条件以及离层临界值、失稳临界值及工程估计值的确定进行了分析 ;通过实例 ,说明了离层监测与反馈的应用 ;工程实践表明 ,采用顶板离层监测是锚固巷道稳定性控制的简易技术手段 ,其技术经济效果明显 ,是一种值得推广的实用方法     

Are chaos and catastrophe theories relevant to environmental sciences?

Data acquired in the area of Environmental Sciences are by their very nature often discontinuous and abrupt. As such, the mathematical theories of catastrophe and chaos may be of use in analyzing such scientific data and in formulating mathematical models.     

可持续环境与发展规划的途径及其有效性

当人们对一些经典概念和模式，如经济最优化模式、生态最适模式、最低安全标准、承载力概念等提出疑问之后，环境与发展规划的方法论也随之面临着严峻的挑战。本文指出：①以经济最优化和生态最适模式指导规划都是非常局限和困难的，规划决不是一个环境和经济决定论的过程，而是一个可辩护的过程；②环境可能会对发展产生所谓的“顶极的”“绝对的”制约，对此，规划必须服从。但是，这种“顶极的”和“绝对的”界线是很难确切定义的，也往往是难以操作的，因而其在环境与发展规划中的意义是相当有限的。必须寻找一些新的有效的战略使规划过程具有可辩护性和可操作性。如何寻求和设计这种辩护战略是可持续发展规划方法论的一个重要领域。生态安全格局途径正是在这一方向上所做的努力。     

以TiCl4—改性硅胶为催化剂的单糖或糖甲基苷的异丙叉化反应

以原甲酸三乙酯为试剂，丙酮为溶剂，在以化学改性硅胶为载体的四氯化钛的催化下，甘露糖及甘露，葡萄，半乳－糖的β甲基苷能方便地、高产率地异丙叉化。