湖北省2008年初低温雨雪冰冻过程气候特征分析

2008年初,湖北省出现了严重的低温雨雪冰冻灾害,直接经济损失高达110亿元以上,有必要对灾害期间的气候特征进行系统、科学的分析和总结。对湖北省76个气象站2008年1月12日～2月3日气温、降水（雪）、日照以及低温持续日数等要素进行时空间差异分析及历史与同期比较,并选取10个代表站历史上所有低温雨雪天气过程,对其过程持续低温日数、最长连续雨雪日数、过程极端低温进行比较分析。结果表明：（1）此次过程的平均气温异常偏低,该省大部为-1～-2℃,比常年同期偏低4～6℃,为各站历史同期最低,其中主要是最高气温异常偏低所致,但极端低温并不低;（2）降雪过程频繁,雨雪量异常偏多;（3）低温冰冻持续时间长,该省大部在16～22 d,位于历史第一;（4）日照异常偏少。持续而稳定的大气环流异常形势是湖北省大范围低温雨雪天气的直接原因。     

中小型燃用烟煤层燃炉NO_x排放特征分析

以86台中小型燃烟煤层燃炉(≤65 MW)的燃料特性分析数据和NOx排放实测数据为基础,通过统计分析方法,研究了锅炉出力、过量空气系数、燃煤挥发分、燃煤氮含量对NOx排放浓度的影响,分析了我国中小型燃烟煤层燃炉NOx的排放与管理控制现状。结果表明,中小型燃用烟煤层燃炉NOx平均排放浓度为324.6 mg/m3;锅炉出力对NOx排放浓度不具有显著影响;燃煤挥发分增高,NOx排放浓度降低;过量空气系数和燃煤氮含量增大,NOx排放浓度增高;并建议在国家层面上尽快制订燃煤锅炉NOx排放标准限值。     

空气中PM_(10)浓度的BP神经网络预报研究

建立了某市PM10浓度预报的分段BP神经网络模型,经验证,所建立的BP预报模型,预测精度比较高,PM10日平均浓度误差大多在-0．010～0．010mg／m^3范围内,相对误差在-20％～20％,表明BP神经网络对PM10的浓度预报是一种有效的工具。     

Multi-effects of gravity and geometric flow channel on the performance of continuous microbial fuel cells

Nowadays microbial fuel cells (MFCs) are a rapidly evolving field and studied extensively because of their simultaneous dual functions of decomposing organic waste matter and eco-power generation. Now, facing their low power density, multiple effects including various gravity conditions ranging from 0 G to 2 G and three kinds of geometric flow channel (serpentine channel, serpentine tapered channel and bio-mixer channel) in MFCs were studied because of their ability to significantly impact the performance of MFCs.Numerical simulation technology, with its significant lessening of time needed and saving experimental costs required was used in this study. Results show that a better power performance was found at a condition of 0.125 G and Reynolds number Re = 41.3 regardless of flow channel in MFCs. In addition, the bio-mixer channel of the flow channels in MFCs will have a better performance than the other two channels because of its lower pressure drop and higher power generation. These findings will provide useful information on enhancing the performance of MFCs, especially with the application of low gravity conditions in the future.     

Applications and implications of direct groundwater velocity measurement at the centimetre scale

Three projects involving point velocity probes (PVPs) illustrate the advantages of direct groundwater velocity measurements. In the first, a glacial till and outwash aquifer was characterized using conventional methods and multilevel PVPs for designing a bioremediation program. The PVPs revealed a highly conductive zone that dominated the transport of injected substances. These findings were later confirmed with a natural gradient tracer test. In the second, PVPs were used to map a groundwater velocity field around a dipole recirculation well. The PVPs showed higher than expected velocities near the well, assuming homogeneity in the aquifer, leading to improved representations of the aquifer heterogeneity in a 3D flow model, and an improved match between the modelled and experimental tracer breakthrough curves. In the third study, PVPs detected subtle changes in aquifer permeability downgradient of a biostimulation experiment. The changes were apparently reversible once the oxygen source was depleted, but in locations where the oxygen source lingered, velocities remained low. PVPs can be a useful addition to the hydrogeologist's toolbox, because they can be constructed inexpensively, they provide data in support of models, and they can provide information on flow in unprecedented detail.     

电絮凝-气浮-砂滤组合工艺除氟

为了有效去除水中的氟离子,对电絮凝-气浮-砂滤组合工艺除氟(F-)离子进行了研究。详细考察了电压、电絮凝停留时间和初始F-离子浓度等参数对除F-离子效率的影响。结果表明:当初始F-离子浓度为1.50 mg/L,停留时间为10 min,电压为15 V条件下,出水F-离子浓度为0.92 mg/L;当初始F-离子浓度为2.5 mg/L,停留时间为15 min,电压15 V条件下,出水F-离子浓度为0.98 mg/L。用Al-Ferron逐时络合比色法表征了电絮凝和气浮单元出水中铝形态随时间的变化。结果显示:电絮凝出水Ala含量随时间增加迅速降低到5%以下,电絮凝和气浮单元出水Alb含量均占到50%以上,Alc含量均随时间增加而增加。     

Dynamics of Plains Cottonwood (<Emphasis Type="Italic">Populus deltoides</Emphasis>) Forests and Historical Landscape Change along Unchannelized Segments of the Missouri River,USA

Construction of six large dams and reservoirs on the Missouri River over the last 50–75 years has resulted in major landscape changes and alterations in flow patterns, with implications for riparian forests dominated by plains cottonwood (Populus deltoides). We quantified changes in land cover from 1892–1950s and the 1950s–2006 and the current extent and age structure of cottonwood forests on seven segments (two reservoir and five remnant floodplain) comprising 1127 km (53 %) of the unchannelized upper two-thirds of the Missouri River. Riparian forest area declined by 49 %; grassland 61 %; shrubland 52 %; and sandbar habitat 96 %; while agricultural cropland increased six-fold and river/reservoir surface area doubled from 1892 to 2006. Net rates of erosion and accretion declined between the 1892–1950s and 1950s–2006 periods. Accretion exceeded erosion on remnant floodplain segments, resulting in declines in active channel width, particularly in 1950s–2006. Across all study segments in 2006, most cottonwood stands (67 %) were >50 years old, 22 % were 25–50 years old, and only 10 % were <25 years old. Among stands <50 years old, the higher proportion of 25–50 year old stands represents recruitment that accompanied initial post-dam channel narrowing; while declines in sandbar and shrubland area and the low proportion of stands <25 years old suggest declines in geomorphic dynamism and limited recruitment under recent river management. Future conservation and restoration efforts should focus both on limiting further loss of remnant cottonwood stands and developing approaches to restore river dynamics and cottonwood recruitment processes.     

烧结烟气氨-Fe(Ⅱ)NTA法同时脱硫脱硝

研究了烧结烟气氨-络合法同时脱硫脱硝。实验结果表明,氨-络合法可以实现烧结烟气同时脱硫脱硝,脱硫脱硝效率最高可达99%和40%。最佳运行条件为:Fe(NTA)浓度为0.075 mol/L,p H为5~6,停留时间为1.24 s(350 L/h的烟气流量)及55℃运行温度。     

鄱阳湖主要入湖口重金属的分布及潜在风险评价

于2011年5月在鄱阳湖的主要入湖口采集了水样和表层沉积物,测定并分析了其中Cu、Zn、Pb、Cd 4种重金属元素的含量和分布。同时采用地积累指数法、潜在生态危害指数法和生态毒性效应等评价方法对沉积物中重金属的污染状况进行了分析评价。结果显示：鄱阳湖主要入湖口水体重金属Cu、Zn、Pb、Cd含量均符合国家渔业水质标准要求,除修河的Pb和信江、饶河入湖口的Cd含量属于国家地表水Ⅱ类水质外,其它所有样地的4种重金属含量均低于国家地表水I类标准限值。沉积物中4种重金属含量均超过鄱阳湖相应背景值且呈积累富集的趋势,其中信江入湖口、饶河入湖口以及三江口已受到重金属的严重污染,潜在生态危害均为中等,而污染最轻的区域为南主湖区。揭示重金属污染程度顺序为Cu＞Zn＞Pb＞Cd;单个重金属潜在生态风险顺序为Cd＞Cu＞Pb＞Zn。进一步的生态毒性效应评价结果表明,虽然鄱阳湖主要入湖口沉积物已经受到重金属污染,但对多数底栖生物未产生明显毒害     

红阳猕猴桃和葛根配方的解酒保肝与抗氧化作用研究

研究红阳猕猴桃、葛根及其配方组合物的解酒保肝与抗氧化作用。采用乙醇所致小鼠自主活动减少和小鼠共济失调实验评价解酒作用;采用小鼠酒精性肝损伤模型评价保肝作用,采用ELISA测定大鼠尿液中8-羟基脱氧鸟苷酸（8-hydroxy-2-deoxyguanosine,8-OHdG）和乙酰—赖氨酸加合物（hexanoyl-lysine adduct,HEL）,以了解配方组合物对DNA过氧化和脂质过氧化的影响。结果表明,红阳猕猴桃—葛根配方可减轻酒精所致小鼠行为抑制和共济失调,提示具有解酒作用;对酒精所致小鼠肝脏MDA、TG水平升高和GSH水平降低有明显改善,提示具有保护化学性肝损伤作用;降低正常和酒精损伤大鼠尿液中过氧化生物标志物水平,提示具有较好的抗氧化作用。红阳猕猴桃—葛根配方具有快速解酒作用,且可持续2—4h;对酒精性肝损伤有一定的保护作用,其机制与抗氧化有关。