改进的BP算法在黄河下游枯季径流预测中的应用

本在黄河下游地区应用多层前向人工神经网络理论,通过改进BP算法,建立下游枯季径流预测的BP神经网络模型,使用花园口-利津水站26年的完整序列测流资料训练和检验网络并用于预测,结果表明,通过本次研究建立的BP网络模型是合理的,可靠的,它较好地反映了黄河下游的枯季径流规律,可为今后黄河流域水资源的统一调度,管理,尤其是预防黄河下游再次出现断流提供科学依据。     

水生植物对面源污水净化效率研究

于自然条件下研究了慈茹、菱白等7种水生植物对面源污水的净化率。结果表明,7种试验植物对水体中N、P均有很高的净化率,其中以慈茹和菱白的综合净化率为最高。由于不同植物对N、P的净化率不同,所以多种植物配置可提高植物对面源污水的综合净化率。     

电厂脱硫产物的处置和综合利用

本文通过对电厂脱硫产物成份的分析,并类比国外技术论述其贮存处置方法,脱硫产物综合利用的用途及合理性.     

径向浓淡旋流煤粉燃烧器直流二次风对流场及NO_x排放的影响

针对径向浓淡旋流煤粉燃烧器直流二交风对出口冷态流动特性的影响进行了试验研究，并在一台２２０ｔ／ｈ锅炉和一台６７０ｔ／ｈ锅炉上进行了工业性试验。冷模试验表明，直流二次风对旋流燃烧器出口气流的流动和混合特性有重要影响。     

Sorption and desorption kinetics of diuron,fluometuron, prometryn and pyrithiobac sodium in soils

Abstract

The sorption and desorption characteristics of four herbicides (diuron, fluometuron, prometryn and pyrithiobac‐sodium) in three different cotton growing soils of Australia was investigated. Kinetics and equilibrium sorption and desorption isotherms were determined using the batch equilibrium technique. Sorption was rapid (> 80% in 2 h) and sorption equilibrium was achieved within a short period of time (ca 4 h) for all herbicides. Sorption isotherms of the four herbicides were described by Freundlich equation with an r² value > 0.98. The herbicide sorption as measured by the distribution coefficient (K_d) values ranged from 3.24 to 5.71 L/kg for diuron, 0.44 to 1.13 L/kg for fluometuron, 1.78 to 6.04 L/kg for prometryn and 0.22 to 0.59 L/kg for pyrithiobac‐sodium. Sorption of herbicides was higher in the Moree soil than in Narrabri and Wee Waa soils. When the K_d values were normalised to organic carbon content of the soils (K_oC), it suggested that the affinity of the herbicides to the organic carbon increased in the order: pyrithiobac‐sodium < fluometuron < prometryn < diuron. The desorption isotherms were also adequately described by the Freundlich equation. For desorption, all herbicides exhibited hysteresis and the hysteresis was stronger for highly sorbed herbicides (diuron and prometryn) than the weakly sorbed herbicides (fluometuron and pyrithiobac‐sodium). Hysteresis was also quantified as the percentage of sorbed herbicides which is not released during the desorption step ω = [n_ad / n_de ‐1] x 100). Soil type and initial concentration had significant effect on ω. The effect of sorption and desorption properties of these four herbicides on the off‐site transport to contaminate surface and groundwater are also discussed in this paper.     

丹东市湿式脱硫除尘器的现状评价

湿式脱硫除尘器取代干式除尘器后除尘效率有较大提高，但它用水量大，腐蚀严重，SO2污染加重，运转费用和操作难度大。对改进湿式脱硫除尘器的脱硫、除尘、消烟、设备维护等提出了保证措施。     

荠菜叶挥发性成分分析

采用水蒸气蒸馏法对荠菜叶挥发油进行了提取。通过毛细管气相色谱—质谱联用法分离并鉴定了其化学成分,用气相色谱面积归一化法测定了各成分的相对百分含量,共分离确定了其中12种化合物,所鉴定化合物的含量占全油的65.62%,主要化学成分为：L-胍基琥珀酰亚胺（21.28%）、植醇（18%）、植酮（9.6%）、油酸（4.71%）、棕榈酸（3.97%）等。     

Sediment Availability and Erosion Rates on Off‐Highway Vehicle Trails in the Ouachita Mountains,USA

Factors influencing sediment availability are assessed and erosion rates are quantified for an off‐highway vehicle (OHV) trail system in the Ouachita Mountains of Arkansas. As of May 2012, the Wolf Pen Gap trail system included 77.0 km of "trails" which consist of county roads; open and closed Forest Service roads; and open and closed OHV trails. For a given trail length, the sediment volume available to be eroded is determined by bare trail width and sediment depth. Four condition types are defined that group trail sections based on statistically different trail widths or depths. Trail construction method appears to influence sediment availability differences more than erosion potential (as indexed by trail slope gradient and length). The range for annual trail erosion rates is estimated as 75 and 210 tonne/ha/yr. The high and low rates are obtained using two independent methods. The 210 tonne/ha/yr rate is computed from mean sediment capture at 30 sediment traps installed for 0.5–1.0 year. The 75 tonne/ha/yr rate is computed assuming all available trail sediment measured in a one‐time sampling is eroded over the next year. We argue in support of this assumption and suggest both rate values may be conservative. Trail erosion rates and sediment trap observations indicate frequent trap cleanout will be needed to continue sediment capture from All Terrain Vehicle trails.     

东海特定海区沉积物-水界面附近P释放的实验研究

以采自长江口外东海表层沉积物为对象，对不同类型的沉积物在模拟海水环境中进行了释P实验。研究表明，在静态条件下，沉积物释P量的高点出现在摇晃后10min左右，大约3h后基本趋于平衡。释P动力学可用Elovich公式与双常数速率公式进行拟合。最大释P量与沉积物的组成密切相关，以粉砂、粘土为主的沉积物释P量高，而砂质为主者释P量低。在释P实验中，铁磷(Fe-P)最为活跃，释放比例最高，其次是吸附态磷(Ad-P)和有机态磷(OP)。它们均属于生物可获得P的范畴。实验结果表明，在合适的水动力条件下，沉积物中的P可以迅速释放到水体．并影响水体的营养状杰和初级生产力。     

民用小锅炉湿式除尘器脱硫性能的评估

目前普遍使用的民用锅炉湿式除尘器多是不加碱性脱硫剂，而以清水作脱硫液，其SO2排放更集中，出口SO2浓度有时比人口还高，并排放大量酸性水蒸汽。用碱作脱硫荆运转费用大，管理部门很难监控企业加碱性脱硫剂。