Adsorption of Photographic Sulphur Sensitizers to Silver Bromide and Silver Sulphide

Heats of adsorption of thiosulphate, thiosulphatoargentate and p-toluenethiosulphonate to silver bromide, silver bromo"dide, silver chloride and silver sulphide were measured using a slow microcalorimeter. The results did not confirm previous evidence for the cluster mechanism for silver sulphide formation during sulphur sensitization. The possibility of this model was discussed. Heats of adsorption of silver and sulphide ions were also measured.     

基于农户视角的农村居民点整理政策效果研究

在新农村建设和农村居民点拆并整理的大背景下,从农户微观视角出发,选取位于江汉平原中部的仙桃市陈场镇陶村五组为典型案例,分别模拟其在自然状态下和空心村整理政策实施下的人口和用地演变,通过两种情况下的对比揭示出整理政策实施后的效果。结果表明渐进归并政策实施后能够加快自然村的消亡和用地整理速度,且可以用较小的代价整理出更多的耕地。但在近期和中期仍然只有少量农村住宅能够得到整理。     

Interactive effects of abiotic,hydrological and anthropogenic factors on fish abundance and distribution in natural run‐of‐the‐river shallow lakes

Ecological processes in lowland rivers are mostly dominated by hydrology and its interactions with other environmental factors. Fish–habitat relationships in rivers are also influenced by human impacts. In this study, we describe patterns of abundance and distribution of fish species in a group of natural lowland river lakes along spatial anthropogenic and abiotic gradients when four hydrologically different summers are compared. We also describe the proportion of the total variances in fish species abundances that can be accounted for by selected abiotic (water conductivity), hydrological (water residence time) and human activity‐derived (total phosphorus (TP) concentration and NO₃:NH₄) variables. Consequently, our main purpose is to explore how abiotic and anthropogenic factors interact to affect fish abundance and distribution together with consistent results across different hydrological conditions. We conclude with a briefly discussion of some management implications. The anthropogenic impacts on water quality, the extreme hydrological variability and the fluctuating abiotic environment affected fish abundance and distribution. Pampa inland silverside Odontesthes bonariensis was benefited from a less human disturbed environment with higher water residence time and total salinity, whereas species as Cyphocharax voga, Parapimelodus valenciennis and Cyprinus carpio found these conditions largely disadvantageous. On the other hand, while most species showed stronger—either negative or positive—response to anthropogenic, hydrological or abiotic factors Oligosarcus jenynsii was only slightly affected. This paper identified the ecological function of a lowland river under its natural flow regime. There are not many opportunities to study unmodified rivers worldwide. Therefore, our findings may help in assessment programmes of fish communities in flow altered and human disturbed aquatic ecosystems. Copyright © 2008 John Wiley & Sons, Ltd.     

基于RS和GIS的松辽平原黑土流失研究

基于RS和GIS技术,利用1986年TM数据和2001年ETM数据,对松辽平原黑土分布现状与动态变化进行监测研究,分析了黑土流失特点及其时空分布规律,并引入冲沟线密度概念量化黑土流失趋势。结果表明:松辽平原典型黑土面积54989.92km²,沿京哈铁路线呈弧形条带状展布;1986～2001年间,黑土区水土流失面积达3765.21km²,减少速度为251.01km²/a,集中在河流两岸、较大建筑用地附近和与盐碱土接壤的地区;仅考虑冲沟的有效作用域,预计到2016年黑土面积平均会有1411.0km²/a转变为冲沟,黑土流失状况不容乐观。     

新型纺纱锭子下轴承系统的研究

传统的锥点形下轴承锭子不适应锭速的进一步提高,为此,新一代高速锭子改进了下轴承结构,新型轴承由径向轴承和轴向轴承两部分组成。指出了锥菜锭子下轴承所存在的缺陷,分析了新型油膜滑动下轴承的特点,并进行了对比试验,分析结果表明,新型下轴承具有很好的动态性能,是高速锭子的一个发展方向。     

美国沿海平原河流渠道化和洪水控制

介绍了美国沿海平原渠道化洪水控制的经验和教训。     

平原圩区大型立式泵机组结构分析与选用

针对目前平原圩区大型泵站在机组结构功能选用上存在的问题,分析了各结构功能的特点,提出了综合考虑泵站特点、运行调节要求和安装检修方便,合理选用机组结构功能的建议。     

Decalcification of activated paper sludge – Fly ash-Portland cement blended pastes in pure water

Decalcification in pure water of ternary Portland cement (TPC) pastes, containing thermally activated paper sludge and fly ash, has been evaluated from the leaching of Ca²⁺ in pure water at the temperature of 20 °C during 90 days. Monitoring of calcium loss showed that the leaching kinetics are controlled by diffusion. The degradation of the material over time is estimated from the calcium effective diffusivity. A similar study of plain ordinary Portland cement (OPC) pastes was carried out for comparison. The results showed lower effective diffusion coefficients of calcium in the case of the TPC pastes. This behaviour is related to its microstructure, which is denser than that of OPC as a result of the pozzolanic activity of both additions.     

基于多源数据集成的松嫩平原

以数字地球科学和数据仓理论为指导,以3S技术、环境模拟技术和计算机编程技术为手段,根据空间信息与非空间信息在地理单元和空间上的存储特征,建立了基于域和对象的公共数据模型,继而构建了不同专属性的空间数据库。以此为基础,通过应用空间数据引擎和空间数据操作对象,首次对面向应用的松嫩平原土地资源空间数据仓进行了分析与设计。     

圩-垛田景观格局下的“水-田-村”布局模式

江苏省兴化地区位于里下河平原腹部的低洼地带,为万水交汇之地,其极具浓郁地域色彩的圩–垛田景观近年来受到众多学者的广泛关注。在区域尺度下,从水文环境变迁和人居环境建设两方面,归纳兴化地区圩–垛田景观发展的演变动力;在市域尺度下,分析兴化地区水利系统、农业开垦及聚落布局的地带特征。从形态学角度,研究兴化地区由东至西,自然地势不断降低、水网逐渐稠密、土地肌理愈发破碎,农田形态发育与聚落形态发展之间的内在关系,以及圩–垛田景观格局下,兴化地区独有的“水–田–村”布局模式。圩–垛田景观的形成是千百年来水与土地不断分解与整合后的结果,圩–垛田景观格局的发展和演变展示了兴化地区传统人居环境营建与自然系统之间相互选择、相互适应的过程,显示了劳动人民治水、农耕和营居的古老智慧。