考虑疏散安全的公共场所人员容量控制研究

利用已建立的大型公共场所人员疏散行为模型,首先针对案例超市Ⅰ,在考虑疏散安全的前提下,研究了公共场所中被疏散人员的个体差异、障碍物的数量和布局差异以及疏散出口的宽度等因素对人员容量的影响,得出了不能简单地通过计算建筑面积或营业面积与给定的人员密度的乘积来设置公共场所人员容量的结论。进一步针对案例超市Ⅱ,在假设其被疏散人员构成与案例超市Ⅰ一致的条件下,通过模拟对比两个案例超市的人员容量,验证了应用均一化的人员密度来控制不同公共场所人员容量的规定不具有普适性,公共场所人员容量的确定必须要根据具体场所的实际情况来具体分析。     

千岛湖水体悬浮颗粒物吸收特性及其典型季节差异

利用千岛湖2012年12月~2013年2月冬季及2013年6~8月夏季的采样数据,分析了千岛湖水体的营养水平和悬浮颗粒物的吸收特性季节变化及空间分布规律.结果表明千岛湖营养水平夏高冬低,整体处于中营养水平.冬季和夏季总悬浮颗粒物吸收系数在440 nm的均值分别为:(0.20±0.07)m-1和(0.24±0.17)m-1;675 nm的均值为(0.07±0.02)m-1和(0.10±0.07)m-1;夏季显著高于冬季(t-test,P<0.05).冬季总悬浮颗粒物的吸收光谱可分为两种情况:西北湖区与浮游植物吸收类似,其它站点与非藻类颗粒物的吸收相似;而夏季,在可见光范围,50%以上总悬浮颗粒物的吸收是由藻类颗粒物贡献,因此,总悬浮颗粒物的吸收光谱曲线与浮游植物光谱曲线类似.冬夏季浮游植物吸收系数差异显著(P<0.05),440 nm均值分别为(0.10±0.03)m-1和(0.17±0.14)m-1;相应地675 nm的均值为(0.05±0.02)m-1和(0.08±0.07)m-1.冬季和夏季440 nm浮游植物比吸收系数(以Chla计)的均值分别为:(0.045±0.010)m2·mg-1和(0.039±0.013)m2·mg-1;675 nm处为:(0.022±0.004)m2·mg-1和(0.019±0.005)m2·mg-1.440 nm和675 nm浮游植物吸收系数随Chla浓度及综合营养状态指数的增加线性增大;比吸收系数和Chla浓度呈幂函数关系,随Chla浓度增大而减小.冬季非藻类颗粒物吸收与无机颗粒物的相关性最好;夏季440 nm非藻类颗粒物吸收与总悬浮颗粒物和有机颗粒物呈线性关系,随着总悬浮颗粒物和有机颗粒物含量增加非藻类颗粒物吸收增加.     

Effect of traffic restriction on atmospheric particle concentrations and their size distributions in urban Lanzhou, Northwestern China

During the 2012 Lanzhou International Marathon, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To evaluate the direct effect of these measures on urban air quality, especially particle concentrations and their size distributions, atmospheric particle size distributions(0.5–20 μm) obtained using an aerodynamic particle sizer(model 3321, TSI, USA) in June 2012 were analyzed. It was found that the particle number, surface area and volume concentrations for size range 0.5–10 μm were(15.0±2.1) cm-3,(11.8±2.6) μm2/cm3and(1.9±0.6) μm2/cm3, respectively, on the traffic-restricted day(Sunday), which is 63.2%, 53.0% and 47.2% lower than those on a normal Sunday. For number and surface area concentrations, the most affected size range was 0.5–0.7 and 0.5–0.8 μm, respectively, while for volume concentration, the most affected size ranges were 0.5–0.8, 1.7–2.0 and 5.0–5.4 μm. Number and volume concentrations of particles in size range 0.5–1.0 μm correlated well with the number of non-CNG(Compressed Natural Gas) powered vehicles, while their correlation with the number of CNG-powered vehicles was very low, suggesting that reasonable urban traffic controls along with vehicle technology improvements could play an important role in improving urban air quality.     

Seasonal dynamics of water bloom-forming Microcystis morphospecies and the associated extracellular microcystin concentrations in large, shallow, eutrophic Dianchi Lake

The increasing occurrence of Microcystis blooms is of great concern to public health and ecosystem due to the potential hepatotoxic microcystins （MCs） produced by these colonial cyanobacteria. In order to interpret the relationships between variations of Microcyst/s morphospedes and extracellular MC concentrations, the seasonal dynamics of phytoplankton community composition, MC concentrations, and environmental parameters were monitored monthly from August, 2009 to July, 2010. The results indicated that Microcystis dominated total phytoplankton abundance from May to December （96%--99% of total biovolume）, with toxic Microcystis viridis and non-toxic Microcystis wesenbergii dominating after July （constituting 65%- 95% of the Microcystis population）, followed by M. viridis as the sole dominant species from November to January （49%--93%）. Correlation analysis revealed that water temperature and nutrient were the most important variables accounting for the occurrence ofM. wesenbergii, while the dominance ofM. viridis was related with nitrite and nitrate. The relatively low content of MCs was explained by the association with a large proportion of M. viriclis and M. wesenbergii, small colony size of Microcystis populations, and low water temperature, pH and dissolved oxygen. The extracellular MC （mean of 0.5 ± 0.2 μg/L） of water samples analyzed by enzyme-linked immunosorbent assay （ELISA） demonstrated the low concentrations of MC in Dianchi Lake which implied the low potential risk for human health in the basin. The survey provides the first whole lake study of the occurrence and seasonal variability of Microcyst/s population and     

富营养水体水生植物-根际微生物净化能力研究

以酶活性分析作为基本研究手段,选择水生维管束植物空心菜作为试验对象,在不同程度的富营养水体中,利用细菌碱性磷酸酶、脱氢酶、脲酶指示植物根际微生物分解营养物质的能力,确定其在水体碳、氮、磷循环中的作用,确定不同程度富营养水体中,水生维管束植物根际微生物分解营养物质的能力和净化水体的作用大小,同时也为确定富营养水体生态修复用水生植物选取提供参考标准。     

基于 Visio 绘图仿真的装甲车辆限制路尺寸设置

目的科学设置装甲车辆驾驶考核限制路尺寸。方法采用Visio绘图工具,对装甲车辆车体、运动状态、道路进行模拟仿真,根据装甲车辆行驶性能参数,测算不同限制路尺寸的理论值。结果通过仿真测算,某新型装甲车辆通过的五杆弯道限制路理论最小总长为42 m,理论最小入口宽为4 m,实际尺寸初始值设置为总长50 m,入口宽为4.5 m。结论采用Visio绘图仿真的方法能够科学准确地进行装甲车辆限制路尺寸设置,为新型装甲车辆限制路尺寸设置提供有效的数据支撑。     

贫营养条件下生物除铁除锰滤池生态稳定性研究

采用将反冲洗排水回流至生物除铁除锰滤池的方式补给滤层细菌数量、回流可利用营养物质.试验从滤池整体除铁除锰效果、微生态特性及优势细菌数量分布3方面考察滤池的生态稳定性.结果表明,在高滤速(10～13.9 m/h)、高锰浓度(3.5～4.5 mg/L)条件下生物滤池对铁锰的去除率达98.9%以上,滤池具有较强的抗负荷冲击能力.铁、锰氧化细菌为滤层的优势菌群,数量达106数量级,它们既附着在滤料表面上(4.3×106个/mL)形成致密的生物膜,又存在于滤料间(6.5×106个/mL)形成以细菌为主体的悬浮絮体,此絮体对铁锰的彻底去除至关重要.经过近5年的连续运行,在不投加营养盐的前提下生物滤池实现了稳定运行,保持了高除铁除锰效率.     

污水处理厂反硝化工艺中的碳源问题

<正>为了满足非常严格的氮排放限制(例如3～5mg/L的总氮排放标准),污水处理厂反硝化过程中使用外加碳源已成为必要条件.研究人员选取了3种碳源——MicroCTM(产品来自马萨诸赛州某环境资源公司)、甲醇和乙酸,评价并     

Effects of As on As uptake,speciation, and nutrient uptake by winter wheat （Triticum aestivum L.） under hydroponic conditions

A hydroponic experiment was conducted to investigate the effects of arsenic （As） stress on growth, nutrition and As uptake, and speciation in shoots and roots of winter wheat （Triticum aestivum L.）. Winter wheat has high tolerance to As. Most As is accumulated in the roots, and an As concentration of 4,421 mg/kg was observed at a solution concentration of 20 mg/L As. Arsenic concentrations in roots were approximately 40-100 times greater than those in shoots. Arsenic in winter wheat roots and shoots occurred as both As^3＋ and As^5＋ species, although As^3＋ was the main species in winter wheat tissues. Arsenic significantly decreased the biomass of winter wheat shoots and roots and affected absorption and transport of micro- and macro-elements in winter wheat tissue. Arsenic treatment significantly increased the concentrations of total Magnesium （Mg） and calcium （Ca） in shoots and enhanced the transport of Mg and Ca from roots to shoots but decreased potassium （K）, nitrogen （N）, and phosphorus （P） concentrations in both shoots and roots, particularly the concentration of P. Concentrations of iron, copper, and zinc in winter wheat shoots were negatively related to As rates, with correlation coefficients （R^2） of 0.93, 0.94, and 0.97, respectively.     

政策发布

修订后的《水污染防治法》以硬指标确保硬约束;我国今年将建上市企业环境信息通报制度;《可再生能源发展“十一五”规划》发布;国家发改委制定印染行业准入条件;“绿色贸易”政策限制“双高”产业。