潜水蒸发系数综合分析

利用河北省冉庄水资源实验站、安徽省五道沟水文水资源实验站、山西省太谷均衡实验站实测的潜水蒸发资料,对潜水蒸发及潜水蒸发系数的变化规律进行了综合分析。提出了不同岩性、不同潜水埋深在有无作物生长条件下的潜水蒸发系数。为华北地区水资源平衡计算潜水蒸发系数的选定提供了参考数据。     

大民屯凹陷烃源岩有机质丰度的恢复

烃源岩有机质丰度的恢复具有重要的现实和理论意义。笔者在对比多种方法的基础上,对大民屯凹陷的烃源岩的有机质丰度进行了恢复。     

数字海洋地图无缝拼接的研究

从目前数字海洋地图的现状出发,针对数字海洋地图由分幅存储方式带来的叠幅（图幅间存在重叠区域）和缝隙两个问题,提出了一种无缝拼接的算法。算法可去除图幅之间的重叠区域,并且可以有效去除由分幅导致的缝隙,将多个图幅的图层要素拼接为物理无缝的数据。     

Uncertainty as the overlap of alternate conditional distributions

An important task in modern geostatistics is the assessment and quantification of resource and reserve uncertainty. This uncertainty is valuable support information for many management decisions. Uncertainty at specific locations and uncertainty in the global resource is of interest. There are many different methods to build models of uncertainty, including Kriging, Cokriging, and Inverse Distance. Each method leads to different results. A method is proposed to combine local uncertainties predicted by different models to obtain a combined measure of uncertainty that combines good features of each alternative. The new estimator is the overlap of alternate conditional distributions.     

Changes in hydrogeological properties of the River Choushui alluvial fan aquifer due to the 1999 Chi-Chi earthquake, Taiwan

Changes in hydrogeological properties of the River Choushui alluvial fan aquifer before and after the 1999 Chi-Chi earthquake, Taiwan, have been identified using pumping tests. Three wells, SH2, YL2 and SC2, located in a compressional zone with high coseismic groundwater levels, were tested. The threshold of the aquifer deformation with respect to transmissivity (T) is greater than that with respect to storage coefficient (S). Decreases in the post-earthquake S are approximately 60% at SH2 and SC2, indicating aquifer compression after the Chi-Chi earthquake. Changes in the post-earthquake T range from 61% increase to 0.8% decrease. Moreover, results from anisotropy analysis of T at SC2 further illustrate that normal stresses induced by the Chi-Chi earthquake have consolidated soil particles. Soil particles dilated laterally after the earthquake, resulting in an increase of the equivalent T. The changes in hydrogeological properties have a considerable influence on spatiotemporal fluid pressure and horizontal groundwater movement, resulting in different amounts of drawdown during post-earthquake pumping.     

鱼耳石中锶和钡富集的影响因素及其环境响应

鱼耳石中元素锶和钡主要来源于鱼类生存的水体,这两种元素通过腮或肠进入内耳淋巴液,继而以类质同象的方式沉淀在耳石晶格内部空位和晶格间隙中。耳石结晶沉淀的整个过程不仅受生物的调控作用,而且还受到外界环境,如水体元素浓度、盐度、温度等因素的影响,因此耳石中某种元素的浓度与其在水体中的浓度之比(元素富集系数)与鱼类所生存的环境之间具有一定的响应关系。在以上各种因素中,水体元素浓度对耳石元素富集系数的影响最为显著。一般来说,耳石中某种元素的含量与水体中相应的元素浓度呈正相关关系,而水体中元素之间就耳石中的富集过程也存在一定的相互促进或抑制作用,如Sr对Ba为协同作用,Ca对Sr、Zn为拮抗作用。另外,水体盐度或温度与元素富集系数之间不存在简单的线性相关关系,而是因鱼种、水体综合环境及元素种类不同而有所差异。研究结果表明:鱼种一定的情况下,耳石中元素富集系数与水体盐度和温度存在良好相关关系。基于以上相关性分析,可以认为耳石中元素富集系数与环境因子(水体元素浓度、盐度、温度)之间存在响应关系。因此,可以选用那些受环境影响大但对自身调控影响小的元素(如:Sr、Zn、Pb、Mn、Ba、Fe、Li、Ni、Cd)来建立耳石与水体环境之间元素富集系数的定量化模型,并利用这种响应关系及定量化模型进行生态环境监测和渔业管理。     

The mass accommodation coefficient of ammonia on water

The mass accommodation coefficient of ammonia gas on water has been determined by measuring the absorption rate of 50–200 ppm NH₃ in one atm of air or helium into a liquid jet of 97 µm diameter as function of the exposed jet length, and comparing the results with numerical simulations which treat as the only free parameter. The model considers in detail transport of NH₃ by molecular diffusion, penetration of the gas/water interface, hydrolysis in the acidified water, and transport of the solutes from the surface into the jet. A correction is applied for the time evolution of the jet surface speed, using literature data on the fluid mechanics of liquid jets. The result of nine sets of independent measurements is

Trace gas exchange at the air/water interface: Measurements of mass accommodation coefficients

A liquid jet of 90 m diameter and variable length has been utilized to determine absorption rates and, hence, mass accommodation coefficients , of atmospheric trace gases. The compounds investigated are HCl (0.01), HNO₃ (0.01), N₂O₅ (0.005), peroxyacetyl nitrate (>0.001), and HONO (0.005). It is concluded that the absorption of these trace gases by liquid atmospheric water is not significantly retarded by interfacial mass transport. The strengths and limitations of the liquid jet technique for measuring mass accommodation coefficients are explored.     

Retailing local food in the Scottish-English borders: A supply chain perspective

Local food is championed as one alternative response to industrial systems of food production and supply. While advocacy for local food is high, there is a lack of empirical evidence about the actual shape and scale of such food supply chains, especially from a retail perspective. Using supply chain diagrams, this paper presents a summary of ‘new’ agro-food geographies for five different retail types—farm shops, butchers, caterers, specialist shops, supermarkets/department stores—that all source local food from suppliers in the Scottish-English borders. Presented as five separate ‘shopping trips’, the paper examines where, how and why retailers source local food. Results reveal the complex nature of local food systems, especially in terms of intra-sector competitive dynamics (with a notable tension between direct forms of retail and established (independent) retailers), links and overlaps with ‘normal’ food retail systems and elastic notions of the ‘local’. The paper also draws a key distinction between locally produced and locally supplied food products.     

Food Deserts in the Prairies? Supermarket Accessibility and Neighborhood Need in Edmonton,Canada*

The U.S. and U.K. literatures have discussed “food deserts,” reflecting populated, typically urban, low‐income areas with limited access to full‐service supermarkets. Less is known about supermarket accessibility within Canadian cities. This article uses the minimum distance and coverage methods to determine supermarket accessibility within the city of Edmonton, Canada, with a focus on high‐need and inner‐city neighborhoods. The results show that for 1999 both of these areas generally had higher accessibility than the remainder of the city, but six high‐need neighborhoods had poor supermarket accessibility. We conclude by examining potential reasons for differences in supermarket accessibility between Canadian, U.S., and U.K. cities.