The impacts of cattle access points on deposited sediment levels in headwater streams in Ireland

Cattle access to streams has been linked globally with degradation of stream water quality, driven largely by bank erosion and resultant instream, fine sediment deposition. The majority of evidence on such effects is however based in arid and semiarid regions of the United States and Australia, with few studies relating to cool temperate climates such as Northwest Europe. In this study, “Quorer” resuspendable sediment samples were taken from riffle geomorphic units upstream (control) and at two points downstream (pressure and recovery) of cattle access points in headwater streams in agricultural catchments in Ireland to assess levels of deposited stream sediment. Samples were taken in April/May (2016) prior to the grazing season and in October (2016) at the end of the grazing season. Sites in good‐high ecological status catchments and less than good ecological status catchments were included in the study. Higher levels of sediment were found downstream of cattle access points in both good‐high status and less than good status catchments; however, the impacts of access points were spatially confined to, in most cases, the area immediately downstream of the point of access. There was a strong correlation between deposited sediment mass and organic matter (OM) mass, with levels of OM increasing linearly with deposited sediment mass. Levels of measured sediment were negatively correlated with riparian habitat health (measured using a qualitative habitat assessment). The results of this study highlight the need for measures to prevent cattle access to headwater streams where access points can be many in order to manage local habitat quality and downstream water quality issues.     

换热器设计中适宜流体用量的确定

利用换热器的操作线来分析讨论流体用量对传热过程的操作费用和设备费用的影响，找出了换热器设计和选型中适宜流体用量的优化确定方法，简便，快捷，具有一定的适用性。     

像增强型夜视系统的图像信息传递

在分析了像增强夜视系统信息传递的基础上，指出像增强器输出端荧光屏至人眼的图像传递过程，构成了像增强夜视系统信息传递量的限制．提出了采用系统信息传递量作为夜视系统设计与评价的方法，利用这种方法可以发现在像增强器增益足以补偿光谱选道衰减的条件下，采用彩色像增强可以大幅度增加夜视系统传输的信息量．     

ATMOSPHERIC DEPOSITION OF CHEMICAL SPECIES TO POLAR SNOW

Particles and gases can deposit from the atmosphere to polar snow by several mechanisms. Dry deposition can be considered to consist of three steps: aerodynamic transport from the free atmosphere to the viscous sublayer near the surface, boundary layer transport across the sublayer, and interactions with the surface. The particle dry deposition mass flux is dominated by the largest particles present in a size distribution. Wet deposition includes in-cloud and below-cloud scavenging, where the former refers to uptake of particles during nucleation of cloudwater as well as scavenging of particles and gases by existing droplets and ice crystals. Of all the wet deposition mechanisms, nucleation scavenging is often the most important mechanism for particles in the polar regions. Finally, incorporation of particles and gases into fog droplets and subsequent settling of the fog to the snow surface can be an important removal process in regions of frequent fog. For Summit, Greenland, the total deposition of MSA, SO₄^2-, Na⁺, K⁺, and Ca²⁺ during May 24-July 13, 1993 was dominated by wet deposition: this mechanism accounted for an average of 62% of the total deposition for these species. Fog and dry deposition accounted for 21% and 17% of the total, respectively. These results suggest that all three mechanisms may need to be considered when estimating total deposition of certain chemical species to polar snow.     

南水北调西线工程可调水量分析

在受水区缺水形势严峻的情况下，引水工程可调水量的确定主要与三个因素有关：一是引水河流及引水坝址径流量；二是坝址上下游用水要求；三是引水水库工程规模。在考虑各种因素影响后，提出各引水坝址可调水量占坝比径流量的比例在70％左右比较合适，按现阶段推荐的两种方案，可调水量可达160亿－170亿m^3.     

2010-2020年深圳市机动车发展和油气需求量预测

介绍了深圳市机动车发展现状,分别用趋势外推法、城市比较分析法和分类法预测了2010-2020年深圳市的机动车保有量,最后预测了机动车的油气需求量。     

分析再热器超温爆漏与水冷壁结焦控制量的关系

文章介绍了宝钢自备电厂在改善锅炉燃烧工况，控制锅炉水冷壁结焦所采取的技术措施，分析了锅炉水冷壁结焦量与锅炉二次再热器烟气出口平均温度的关系，为解决锅炉水冷壁结焦所引发的二次再热器超温爆漏问题提供了依据。     

垄作冷渍型稻田氮、磷、钾化肥适宜施量及施用方法研究

通过垄畦栽冷渍型稻田早、中稻化肥不同施量及施用方法的田间试验,建立氮、磷、钾化肥施用量与产量的回归方程,推导出早、中稻氮、磷、钾化肥最佳施用量;在施肥量相等情况下,深施比表施肥效好,钾肥不足情况下,以稻草代钾肥同样取得较好增产效果。     

热分配表蒸发量的影响因素及修正

热分配表的蒸发量会因系统流量、散热器种类、片数、安装方式、房间位置的不同而使得相同的蒸发量代表着不同的散热量。确定修正系数不仅必要，而且需要经过大量的试验验证。     

辽宁省节水工作存在问题及对策

辽宁省是水资源严重短缺的省份之一，水资源不足已成为制约全省经济社会可持续发展的瓶颈。通过对全省大型取用水户的调查分析，找出了辽宁省节水工作中存在的问题，提出了节约用水工作的对策和建议。