CORRELATION OF SELECTED WELL WATER QUALITY PARAMETERS WITH SOIL AND AQUIFER HYDROLOGIC PROPERTIES1

ABSTRACT: The geographical distribution of well water specific electrical conductivity and nitrate levels in a 932 km² ground water quality study area in the Fresno-Clovis, California, indicated that frequently areas of lower ground water salinity were also areas of relatively greater soil and aquifer permeability. From these observations and certain assumptions we hypothesized that the quality of the well water should be better in areas with permeable soils and geological formations. Correlation and multiple linear regression analysis supported this hypothesis for well water salinity. However, well water nitrate levels were significantly negatively correlated with only the estimated equivalent specific yield of the aquifer system. The multiple R² values of the most significant multiple linear regression models showed that only a fourth to a third of the variability in well water specific electric conductivity and nitrate levels could be ascribed to the effects of the hydrogeological parameters considered with more than 90 percent confidence. This indicates that three-fourths to two-thirds of the variability in ground water salinity and nitrate levels may be related to land use. Thus, there is considerable room for land use management techniques to improve ground water quality and reduce its variability.     

汶川8.0级地震灾后响应研究——以灾后学生响应为例

基于网络信息,以学生群体对汶川8.0级地震响应为研究对象,通过对搜集到的复杂网络信息的分类和分级,刻画出非灾区学生群体的灾害响应能力,探讨了学生灾后响应主要类型、强度的空间分异及灾后响应的驱动力。结果表明：①学生灾后响应的主要类型是学生自发捐款、中小学异地复课等;②造成学生灾后响应空间差异的主要因素不是交通条件,而是空间距离导致心理疏离;③学生灾后响应的驱动力随时间的变化特征不同,其中满足自我强化需要的响应速度快但持续性较低,而满足灾源地的需要的响应速度慢但持续性高。     

Heterogeneity of soil surface ammonium concentration and other characteristics, related to plant specific variability in a Mediterranean-type ecosystem

Heterogeneity and dynamics of eight soil surface characteristics essential for plants—ammonium and nitrate concentrations, water content, temperature, pH, organic matter, nitrification and ammonification rates—were studied in a Mediterranean-type ecosystem on four occasions over a year. Soil properties varied seasonally and were influenced by plant species. Nitrate and ammonium were present in the soil at similar concentrations throughout the year. The positive correlation between them at the time of greatest plant development indicates that ammonium is a readily available nitrogen source in Mediterranean-type ecosystems. The results presented here suggest that plant cover significantly affects soil surface characteristics.     

SQL CLR聚合函数在环境质量业务数据计算中的应用

结合声环境质量业务数据处理的实践,阐述了开发部署SQL CLR聚合函数的意义和关键步骤,并通过实际场景应用展现了SQL CLR聚合函数在复杂数据计算中具备的高效性、高可复用性,展望了该项技术在其他环境业务数据处理中的应用前景。     

主体功能区建设与区域协调发展:促进亦或冒进

当前我国的区域发展不平衡问题日益凸显,国家“十一五”规划中出台的主体功能区战略试图根据一些理想的条件和标准对我国区域空间进行合理的重新划分和建构,从而达到促进我国区域协调发展的目的.决策层对区域协调发展的关注从早期狭义上更多地单纯强调经济发展的人民生活水平差距的逐渐缩小,后来逐渐扩展到广义上的区际实际收入水平和公共服务的均等化过程.根据中国2001-2009年的数据,我们发现无论是狭义上还是广义上,我国区际发展不协调程度都呈现扩大趋势,并且广义的区域不协调程度远超过狭义的区域不协调程度.主体功能区战略是逻辑意义上的以地为本,同时也是对区域过去发展水平的一个事后承认或被动承认,中国区域经济的发展水平与主体功能区的开发顺序和开发重点形成了相互促进的同向递增关系.主体功能区的划分标准有着较大随意性和不严谨性,加上相关配套政策和措施的不完善,主体功能区建设短时期内不会缩小反而可能会加大我国本已不小的区际发展差距.     

森林旅游地功能分区规划初探

功能分区是协调森林旅游地自然保护和旅游利用之间关系的有效手段和管理工具 ,本文在分析了我国可以开展森林旅游的地区的资源环境、社会经济特征之后 ,探讨了森林旅游地功能分区规划的基本目标、原则及方法。     

Variations in surface functional groups, carbon chemical state and graphitization degree during thermal deactivation of diesel soot particles

The thermal deactivation of diesel soot particles exerts a significant influence on the control strategy for the regeneration of diesel particulate filters (DPFs). This work focused on the changes in the surface functional groups, carbon chemical state, and graphitization degree during thermal treatment in an inert gas environment at intermediate temperatures of 600°C, 800°C, and 1000°C and explore the chemical species that were desorbed from the diesel soot surface during thermal treatment using a thermogravimetric analyser coupled with a gas-chromatograph mass spectrometer (TGA-GC/MS). The surface functional groups and carbon chemical state were characterized using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The graphitization degree was evaluated by means of Raman spectroscopy (RS). The concentrations of aliphatic C–H, C–OH, C=O, and O–C=O groups are reduced for diesel soot and carbon black when increasing the thermal treatment temperature, while the sp²/sp³ hybridized ratio and graphitization degree enhance. These results provide comprehensive evidence of the decreased reactivity of soot samples. Among oxygenated functional groups, the percentage reduction during thermal treatment is the largest for the O–C=O groups owing to its worst thermodynamic stability. TGA-GC/MS results show that the aliphatic and aromatic chains and oxygenated species would be desorbed from the soot surface during 1000°C thermal treatment of diesel soot.     

云南省主体功能区水资源开发利用初步研究

云南省河湖众多，降水丰富，水资源总量居全国第三位，然而在社会经济发展中，云南省水资源分布与利用之间的矛盾日渐突出。从云南省各主体功能区的自然、经济、社会、科技等因素入手，分析了各主体功能区水资源开发利用和管理的现状及其影响因素，提出了云南省各主体功能区水资源可持续利用的建议。     

Influence of a Large Herbivore Reintroduction on Plant Invasions and Community Composition in a California Grassland

Abstract:  Despite many successful reintroductions of large mammalian herbivores throughout the world, remarkably little attention has focused on how these actions affect native and exotic vegetation at reintroduction sites. One such herbivore is tule elk ( Cervus elaphus nannodes ), which was on the brink of extinction in the mid 1800s, but now has numerous stable populations due to intensive reintroduction efforts. Here, we summarize results from a 5-year exclosure experiment that explored the effects of tule elk on a coastal grassland in northern California. Elk significantly altered the species composition of this community; the response of annual species (dominated heavily by exotic taxa) was dramatically different from perennial species. Elk herbivory increased the abundance and aboveground biomass of native and exotic annuals, whereas it either had no effect on or caused significant decreases in perennials. Elk also decreased the cover of native shrubs, suggesting that these herbivores play an important role in maintaining open grasslands. In addition, elk significantly reduced the abundance and biomass of a highly invasive exotic grass , Holcus lanatus, which is a major problem in mesic perennial grasslands. Our results demonstrate that the successful reintroduction of a charismatic and long-extirpated mammal had extremely complex effects on the plant community, giving rise to both desirable and undesirable outcomes from a management perspective. We suspect that these kinds of opposing effects are not unique to tule elk and that land managers will frequently encounter them when dealing with reintroduced mammals.     

Formaldehyde oxidation on Pd/USY catalysts at room temperature: The effect of acid pretreatment on supports

The complete catalytic oxidation of formaldehyde (HCHO) to CO₂ and H₂O at room temperature is a green route for indoor HCHO removal. Zeolite is an excellent carrier material for HCHO oxidation due to its large surface area, intricate pores and high adsorption capacity. However, the zeolite-supported noble metal catalysts have currently shown relatively low activity especially at room temperature. In this work, we present a facile acid treatment strategy for zeolite catalysts to improve the hydroxyl concentration and further enhance their catalytic activity for HCHO oxidation. Activity tests illustrated that HCHO could be completely oxidized to CO₂ and H₂O at a nearly 100% conversion rate with a weight hourly space velocity (WHSV) of 150,000 mL/(g∙hr) at 25°C, when the support of Pd/USY catalysts was pretreated by hydrochloric acid with a concentration of 0.20 mol/L. The characterization results revealed that the active hydroxyl groups originated from the dealumination in the acid treatment play a key role in the HCHO oxidation reaction. The deduced reaction mechanism suggests that bridging hydroxyl groups may oxidize HCHO to dioxymethylene (DOM) species and terminal hydroxyl groups are responsible for the transformation of DOM groups to formate (HCOO) species.