Temporal-spatial dynamics of vegetation variation on non-point source nutrient pollution

The temporal-spatial interaction of land cover and non-point source (NPS) nutrient pollution were analyzed with the Soil and Water Assessment Tool (SWAT) to simulate the temporal-spatial features of NPS nutrient loading in the upper stream of the Yellow River catchment. The corresponding land cover data variance was expressed by the normalized difference vegetation index (NDVI) that was calculated from MODIS images. It was noted that the temporal variation of land cover NDVI was significantly correlated with NPS nutrient loading. The regression analysis indicated that vegetation not only detained NPS nutrient pollution transportation, but also contributed to sustainable loading. The temporal analysis also confirmed that regional NDVI was an effective index for monthly assessment of NPS nitrogen and phosphorus loading. The spatial variations of NPS nutrient loading can be classified with land cover status. The high loadings of NPS nitrogen in high NDVI subbasins indicated that forestry and farmland are the main critical loss areas. Farmland contributed sustainable soluble N, but the loading of soluble and organic N from grassland subbasins was much lower. Most P loading came from the areas covered with dense grassland and forestry, which cannot directly discharge to local water bodies. However, some NPS phosphorus from suburban farmland can directly discharge into adjacent water bodies. The interactions among nutrient loading, NDVI, and slope were also analyzed. This study confirmed that the integration of NPS modeling, geographic information systems, and remote sensing is needed to understand the interactive dynamics of NPS nutrient loading. Understanding the temporal-spatial variation of NPS nutrients and their correlations with land cover will help NPS pollution prevention and water quality management efforts. Therefore, the proposed method for evaluating NPS nutrient loading by land cover NDVI can be an effective tool for pollution evaluation and watersheds planning.     

汨罗市再生资源产业现状及发展战略研究

汨罗市作为我国循环经济重要领域——再生资源回收利用体系建设试点基地,再生资源产业历史悠久,已初步建立社会化的再生资源回收系统、加工利用系统和废弃物资无害化处置系统,取得显著的经济、社会和环境效益。在面向“十一五”的新时期,汨罗市必须针对再生资源产业存在的“两散一低”问题,立足科技创新,完善技术开发体系、创新网络体系、政策支持体系、管理服务体系,依托汨罗市再生资源产业园以产业集群的理念谋划再生资源产业未来发展战略。     

The Nutrient Status of Some Graminaceous Species in Britain. 1. Molinia Caerulea (L.) Moench

Above-ground biomass biomass of Molinia caerulea from 36 sites throughout Britain was analysed for concentrations of elements (N, P, K, Ca, Mg, Fe, Mn, Cu, Zn and Na), with matching analyses of soil nutrients, together with pH and LOI. Between-year and seasonal variation in the nutrients was also studied at one of the sites. the grass was found on acid sites ranging between pH 3.1 and 5.8. the soil humus content varied widely, and there were significant correlations between that and elements (N, P, K, Ca, Mg and Na) in the soil. Concentrations of calcium, magnesium, zinc and manganese in the plant material were significantly correlated with extractable levels in the soils. Between year variation in the plant nutrient concentrations at one site was of a similar order to variation between the sites. Generally there was less variation in nitrogen, phosphorus and potassium tissue levels than in calcium, magnesium, zinc and copper. Iron and sodium were the most variable. Tissue concentrations of nitrogen, phosphorus, potassium and copper declined throughout the growing season, whereas magnesium, calcium and iron built up until August/September after which a decline set in as the leaves senesced. the results are discussed in relation to the importance of standardizing the time of sampling, in comparison with concentrations of tissue levels in other plants and the growth strategy of this deciduous grass.     

RETRACTED ARTICLE: Removal of lead and cadmium ions from aqueous solutions using the macroalga Caulerpa racemosa

Sediment bulk parameters and fatty acid biomarkers were used to investigate the relative contribution of major sources of particulate organic matter during upwelling and non-upwelling conditions, at organic enriched sites on the south-eastern Brazilian coast. The degradation state of the organic material and its implications for benthic food webs were also evaluated. Temperature and salinity values indicate the intrusion of the South Atlantic Central Water in spring with a strong influence at station 4S. C:N ratios and fatty acid biomarkers suggest that sedimentary particulate organic matter is mainly autochthonous and originated from phytoplankton, zooplankton and bacteria, with a minor terrestrial contribution. Short-chain saturated fatty acids predominated, indicating the prevalence of partially degraded detritus. An exception was station 4S, where polyunsaturated fatty acids dominated, indicating the input of labile organic matter linked to upwelling of the South Atlantic Central Water. Fatty acid concentrations and the organic carbon content of the sediments suggest that food quantity is not a limiting factor for benthic fauna. Despite the high organic background of the sediments, the sporadic inputs of labile organic matter associated with South Atlantic Central Water intrusions may produce an important impact on benthic fauna and on the biogeochemistry of the sediments.     

警用热防护材料的应用研究和发展概况

热防护装备是警察面对火灾和高温时保存生存力和提高战斗力的必备装备,因此研究热防护材料的性能和防护机理显得尤为重要。本文分析了在警用领域热防护材料的研究现状,讨论了热防护材料的性能与表征方法,最后对新型热防护材料气凝胶的发展现状进行了介绍。     

瓦斯爆炸实验研究进展及展望

瓦斯爆炸事故是煤矿的主要灾害之一,为了预防和控制煤矿井下瓦斯爆炸事故的发生,国内外研究者采用理论、实验室实验和数值模拟实验等手段对瓦斯爆炸机理、瓦斯爆炸传播规律等进行了深入研究,本文从瓦斯爆炸实验室实验和瓦斯爆炸数值模拟实验两方面入手,对瓦斯爆炸的研究进展情况进行了分析总结.对于瓦斯爆炸实验室研究,分析总结了现有瓦斯爆炸实验手段以及瓦斯爆炸传播特性研究情况;对于数值实验研究,分析总结了瓦斯爆炸数值模拟模型、现有瓦斯爆炸数值模拟商业软件以及软件应用情况.最后对瓦斯爆炸未来需要深入研究的问题提出了展望.     

刍议建筑施工现场安全管理

建筑工程施工是一项多工种、多专业的复杂的系统工程,具有流动性强、周期长、受环境影响大的特点,施工现场管理的目的是有效地完成施工项目的合同目标,使企业取得一定的经济效益。安全管理是施工现场管理的基础,施工现场安全管理是一个系统工程,它所涉及的系统是一个人、机、料、法、环、测的系统,所研究的问题,也是人、机、料、法、环、测系统工程学的问题。安全管理的根本任务在于贯彻"安全第一,预防为主、综合治理"的安全方针,降低安全风险,防止事故发生,保障人民生命和财产安全。本文介绍了建筑施工现场安全管理的现状,分析了造成建筑施工安全事故的主要原因,并就如何贯彻"安全第一、预防为主、综合治理"的安全方针,有针对的提出了加强建筑施工现场安全管理的对策,可供同行借鉴和参考。     

地铁运营安全及对策研究

从城市轨道交通发展及 2 0 0 8年奥运会在北京召开的现状来看 ,如何最大限度地保证运营安全是我国地铁交通急需解决的关键技术难题之一。在对国际和国内地铁运营安全形势分析的基础上 ,笔者提出了地铁运营安全防范的人、物、制度和社会环境四要素 ,以利于下一步地铁运营安全工作的开展。人的要素是指乘客要有较强的安全防法范意识 ,地铁工作人员具有高素质的工作水平。物的要素是指地铁装备防灾抗灾能力强。制度的要素是指安全管理制度规范和完备。社会环境的要素是指全社会共同努力 ,综合整治预防灾难。     

试论我国生态型城镇的创建

介绍了我国生态型城镇创建的现状及存在问题，从生态经济系统、生态社会系统、生态环境系统、生态基础设施系统方面介绍了生态型城镇创建的重点领域，并从机构保障、法律保障、资金保障、人才保障方面提出了生态城镇创建的保障措施。