九连山自然保护区常绿阔叶林冰雪灾害研究

以九连山国家级自然保护区典型常绿阔叶林为对象,研究树木属性、地形因子与冰雪灾害受损程度的关系.结果表明:九连山常绿阔叶林(DBH≥10 cm)以栲属物种占据主要优势.断梢率、腰折率、翻蔸率和平均受损指数(MDI)最高的树种分别为马尾松、米槠、丝栗栲和米槠,最低的树种分别为红楠、丝栗栲、枫香和罗浮柿.断梢率与胸径(DBH)、树高(H)显著正相关(P<0.01),与H/DBH显著负相关(P<0.01);腰折率与DBH显著负相关(P<0.01);翻蔸率与DBH显著负相关(P<0.01).林分受损程度分析显示,在22≤DBH<24 cm、15≤H<17 m或100≤H/DBH<110时,MDI值最高,在40≤DBH<42 cm、5≤H<7 m或H/DBH≥120时,MDI值最低.坡向对腰折率和MDI值影响显著(P<0.01),N-NE生境中MDI值最高;坡度对树木不同受损指标影响不显著(P>0.05),坡度30°～40°生境中MDI值最高.     

强化浅基质层干植草沟对道路径流的脱氮效果

搭建6个不同结构和介质组成的浅基质层干植草沟模拟柱,在基质层添加较多发酵木屑,利用进水期的脱氮作用,并设置饱水层提高设施落干期脱氮能力,从而强化设施全周期脱氮效果.以半人工道路径流作为进水,考察各模拟柱运行效果,并结合分层取样水质检测结果和模拟柱内体积含水率、ORP的变化过程,分析氮素在不同模拟柱内的去除机制.结果表明:在运行参数相对实际应用环境更为不利的条件下,设置饱水层的模拟柱的TN去除率在67%～78%; TN去除过程主要发生在进水期,且在含较多发酵木屑的基质层即被大量去除;设置饱水层不仅可提高落干期设施脱氮能力,还可保证较浅的基质层在进水期快速达到适宜反硝化的缺氧条件,从而保证进水期设施的脱氮效果;设置持水性过渡层并在其中放置有机质可以有效平衡饱水层碳源补给并控制有机质淋失的问题.     

除尘器入口烟道流场流动力学数值模拟技术

结合燃煤电厂电袋复合除尘器的入口烟道气流分布的工程案例,采用计算流体动力学（简称CFD）数值模拟技术,对烟道内的速度场进行三维数值模拟;根据分析结果进行烟道的导流板的设置,改善烟道的流场,并使入口烟道的各分支烟道流量分配均匀。对比现场烟道流量分配的测试结果,验证了CFD模拟计算的准确性。     

GRAZED STUBBLE HEIGHT AS A CRITERION FOR CONTROLLING SEDIMENT PRODUCTION FROM GRAZING LANDS1

ABSTRACT: Efforts by state and federal agencies to develop standards and guidelines for protecting and enhancing water quality on grazing lands have led to suggestions that grazed stubble height criteria could be used to determine when cattle should be removed from a specific pasture or grazing area. Until recently only indirect scientific evidence from agronomy and laboratory studies gave support to the stubble height concept. Consequently, a grazing study was initiated on a Montana ranch in 1997 to determine the reduction in overland sediment achieved by grazing a pasture to a predetermined stubble height. Treatments consisted of 7 cm (3 in) grazed, 7 cm (3 in) clipped or mowed, 15 cm (6 in) grazed; 15 cm (6 in) clipped and untreated or natural forage plant height. The five treatments were used in a two‐year trial spanning 1997 to 1999. At the conclusion of this study the magnitude of sediment production was related to the number of intense rain events during the March through June period rather than total precipitation. There was a significant year effect in terms of sediment accumulation (P < 0.01) but no year by treatment effect (P = 0.11). Even though a significant difference in sediment accumulation was detected between the shorter and taller stubble heights (P = 0.04) in both 1998 and 1999, the difference could not be explained by grazed stubble height alone. Close grazing (7 cm stubble) consistently ranked lowest in sediment production (P < 0.01) among all treatments, including the ungrazed control. These results suggest that changes in plant community structure and microtopographic caused by grazing influence sediment entrapment (retention) on hillslopes more than those caused by plant height.     

DETERMINING RAINS OF HYDROLOGIC CONSEQUENCE IN CHICAGO FOR FORECASTING APPLICATIONS1

ABSTRACT: Accurate forecasting of heavy rainstorms that affect the Chicago Metropolitan area and lead to the undesirable release of storm runoff into Lake Michigan is a major objective. These releases (overflows) were found to be produced by storm events yielding 2 inches or more in a few hours, although only 24 percent of such ≥ 2-inch storms in the area during 1948-1981 produced overflows. Failure to forecast properly or to be able to react to these 2-inch overflow producing events has occurred most often in the spring and fall, although relatively often in June and July in recent years. These overflows have exhibited an inexplicable trebling during 1972-1981 without an increase in ≥ 2-inch storm events. This type of troublesome storm can be reliably predicted, using a recently developed radar man forecast system for the Chicago area.     

DISCHARGE AND SUSPENDED SEDIMENT PATTERNS OF AN INTERMITTENT COLD DESERT STREAM1

Sage Creek in south‐central Wyoming is listed as impaired by the U.S. Environmental Protection Agency (USEPA) due to its sediment contribution to the North Platte River. Despite the magnitude of sediment impacts on streams, little research has been conducted to characterize patterns of sediment transport or to model suspended sediment concentration in many arid western U.S. streams. This study examined the relationship between stream discharge and suspended sediment concentration near the Sage Creek and North Platte River confluence from 1998 through 2003. The objectives were to determine patterns of stream discharge and suspended sediment concentration, produce a sediment prediction model, and compare sediment concentrations for the six‐year period. Stream discharge and suspended sediment transport responded rapidly to convective storms and spring runoff events. During the study period, events exceeding 0.23 m³/s accounted for 92 percent of the sediment load, which is believed to originate from erodible headwater uplands. Further analysis of these data indicates that time series modeling is superior to simple linear regression in predicting sediment concentration. Significant increases in suspended sediment concentration occurred in all years except 2003. This analysis suggests that a six‐year monitoring record was insufficient to factor out impacts from climate, geology, and historical sediment storage.     

SIMPLE MEASUREMENTS OF SOIL SURFACE MICRORELIEF CHARACTERISTICS1

ABSTRACT: Soil surface roughness and the topographic orientation of microrelief influence runoff and water storage. Distances measured following the surface of the microrelief and horizontally across the area with the microrelief can be used with the number of microridges or microhills to estimate the average cross-sectional areas of the depression, the microslope angles, and crest heights. Microridge sideslope angles which effect the rate of runoff were estimated reasonably well in field plots by the method.     

人工快速渗滤系统治理暴雨径流污染研究

土地处理技术是一项简单高效的污水处理技术,试验利用人工快速渗滤系统对武汉动物园暴雨径流进行了治理研究。试验结果表明,除总悬浮颗粒外各水质指标都达到了《污水综合排放标准》(GB8978-1996)一级排放标准,具有良好的污水深度处理能力。系统对水量的削减较显著,在22.1cm/d的高水力负荷下,削减率达59.5%。     

Abundance and community of snow bacteria from three glaciers in the Tibetan Plateau

Bacterial abundance and diversity in snow of East Rongbuk,Laohugou and Hailuogou glaciers on the Tibetan Plateau were investigated through epifluorescence microscope and denaturing gradient gel electrophoresis.Cell abundance ranged from 4.0 × 10 3 to 290.2 × 10 3 cells/mL.The phylogenetic trees placed the 16S rRNA sequences in four major groups:Proteobacteria,Firmicutes,Actinobacteria and Bacteroidetes.Brevundimonas,Flavobacterium,Hymenobacter,Bacillus,Polaromonas,Rhodoferax and Streptomyces were widely distributed bacteria in glaciers from different cold regions.The remaining five genera of Hylemonella,Delftia,Zoogloea,Blastococcus and Rhodococcus were endemism,only recovered from our investigated glaciers.It is proposed that the three glaciers on the Tibetan Plateau provide a specific ecological niche for prolonging survival of diverse microbial lineages.     

城市小区雨水径流水质监测及特性分析

通过对上海理工大学校园区的不同下垫面产生的径流水质的监测,及其对污染主要影响因素与污染程度的分析表明,下垫面材料、降雨历时、降雨强度及降雨量等是小区雨水径流水质的重要影响因素。小区径流水质的主要污染为有机污染及悬浮固体污染,且有机污染指标COD、悬浮固体污染指标SS、浊度随径流历时的变化满足指数方程。