超细颗粒物凝聚中试试验均匀给料方案研究

给料的均匀性对PM2.5团聚试验至关重要,运用数值方法,采用LES模型计算湍流流场,采用DPM模型计算颗粒运动轨迹,分析PM2.5团聚中试试验台烟道内加设钝体后颗粒的均匀分布,得到了水平烟道各截面处颗粒浓度分布及数值的均方差曲线,发现在试验台圆方管处加设钝体,能有效改善烟道内煤灰颗粒的均匀分布。     

The effects of sinusoidal leading edge of turbine blades on the power coefficient of horizontal-axis wind turbine (HAWT)

In order to improve the aerodynamic performance of horizontal-axis wind turbine (HAWT), a sinusoidal shape is applied to turbine blade. In this study, four types of modified blades were chosen based on variations in amplitude and wavelength of protuberance along the leading edge. Compared with the baseline model, the power coefficients (C_p) of HAWT with modified blades were improved, especially at low tip speed ratios. At low wind speed (V = 6 m/s), blades with short wavelength obtain significant improvement in C_p compared with the baseline model. As wind speed increases, this improvement decreases. In addition, turbine blade with large amplitude and long wavelength obtains better C_p values at higher wind speeds than lower ones, which have a great potential to be more superior at relatively higher wind speeds.     

微生物絮凝剂的研制及其对水体叶绿素a的去除

从土壤中分离到一株能产高效絮凝剂的细菌,定名为SKDX-1。对该菌株产生絮凝剂的最佳生长条件进行了研究,结果表明,该菌株在28℃,摇床(150 r/min)培养条件下,产絮凝剂的最适pH范围为7～8,最佳利用的碳源为蔗糖,氮源为酵母膏。利用蛋白质类和糖类化合物的特征反应对本研究中制备的微生物絮凝剂的成分进行分析,结果表明,该絮凝剂主要成分为蛋白质和糖类物质。分别以城市景观水体和高岭土悬浊液为材料,分析该絮凝剂的去除效率,结果表明,该絮凝剂对水体中叶绿素a的去除率高达87.14%,对高岭土悬浊液的去除率为96%。细菌理化实验表明,该菌株为革兰氏阴性,菌落乳白色、边缘光滑。     

Transport infrastructures,environment impacts and tourists' welfare: a choice experiment to elicit tourist preferences in Siena–Italy

Transport infrastructures have been investigated as drivers of tourist demand. Specific attention has been devoted to air transport infrastructure and services. However, the literature on this issue is scanty. Moreover, few studies focus on ex-ante valuation of tourists' preferences for mobility systems. This study contributes to this literature by presenting a case study on the re-organization of the mobility system to access the city of Siena, Italy. A choice experiment is carried out to elicit tourists' preferences for distance, time, cost, travel mode, along with the environmental impact of infrastructure. The latter factor turns out to be particularly relevant in explaining tourists' choices and welfare. Furthermore, the results appear to be robust and not significantly dependent on design settings (specifically the number of alternatives). While these results only refer to a single case study, they seem to suggest that new transportation facilities do not necessarily cause an increase in tourism flows.     

异相Fenton试剂催化氧化-混凝沉淀深度处理焦化废水

针对焦化废水二级生化处理出水COD、色度和浊度无法达标的问题,实验研究了异相Fenton试剂催化氧化法和混凝沉淀法以及二者联合深度处理焦化废水的效果,分别探讨了H2O2、FeOOH投加量、初始pH,混凝剂投加量及种类对COD去除的影响,确定了最佳运行条件,采用GC-MS分析了联合工艺对废水中有机物的去除规律。异相Fenton试剂催化氧化静态实验研究表明,当H2O2(10%)投加量为2 mL/300 mL,FeOOH投加量为3 g/L,初始pH为4~6之间,处理效果最佳;混凝沉淀实验中最佳的混凝剂为聚丙烯酰胺阳离子,最佳投加量为8 mg/L。异相Fenton试剂催化氧化-混凝沉淀联合工艺深度处理焦化废水,出水COD基本在90 mg/L左右,浊度为0.8NTU左右,色度为40度以下,满足国家污水综合排放二级标准(GB8978-1996)。GC-MS分析显示,联合工艺能有效减少废水中有机物的种类和浓度,并将废水中长链大分子化合物和杂环化合物分解为短链的小分子化合物,构成联合工艺出水COD的主要是小分子有机物,尤其是卤代烷烃含量较高。     

堆石料强度和变形性质的大型三轴试验及模型对比研究

在饱和试样大型三轴试验成果基础上,对两种堆石料(垫层料、次堆石)的变形与强度特性变化规律进行了总结。认为围压是影响堆石料强度和变形特性的最重要因素;堆石料的非线性应力应变关系用邓肯张模型和指数模型来拟合都基本令人满意,但指数模型会高估初始剪切模量;堆石料的径向应变与轴向应变关系可以分成两段,并能够依次用双曲线和直线来模拟;随着围压的升高,堆石料的剪胀性会急速降低,颗粒破碎可能性会增加,因此相应的最大主应力比和内摩擦角会随之发生明显的减小,并且可以用幂函数关系很好的拟合它们与围压的关系。     

不同吊顶材料对燃烧室内和狭长走廊中烟气危害性的影响

选取建筑用材中几种常用的吊顶材料,研究火源以及火势迁移等因素对狭长走廊中烟气危害性的影响.试验在小尺寸实验台上进行,研究了采用不同吊顶材料时燃烧室和走廊中烟气的体积分数峰值、峰宽时间及到达峰值的时间,揭示了烟气的危害程度.试验表明,不同吊顶材料对火灾中烟气的危害性有明显影响.复合板吊顶材料能够显著增加烟气体积分数峰值并缩短到达峰值的时间,其烟气体积分数峰值约为单纯钢板吊顶情况下的两倍.PVC吊顶材料在同样火灾载荷下的塌落倾向最明显.     

Effect of application of phosphate and organic manure-based fertilizers on arsenic transformation in soil columns

The mobility of arsenic in Cambisol under the influence of added barnyard manure and application of a phosphate solution to the soil was described on the basis of column experiments. A soil sample containing 126 mg/kg total As and 3.72 mg/kg specifically-sorbed As was extracted using demineralized water (DIW) or a 28 μmol/l phosphate solution in a column containing untreated soil and in a column with added barnyard fertilizer. The pH, Eh, alkalinity, main components, including DOC, and selected trace elements (Al, Mn, Pb, Cu, Zn, Cd, Cr, Co, Ni, Ba and As) were determined in the extracts. Hydrodynamic tests of the flow and transport of the substances in the columns were carried out. The addition of barnyard manure was manifested in elevated concentrations of the main inorganic components, DOC and Al and a decrease in the Eh value and Mn concentration. Application of a phosphate solution was manifested in a decrease in the NO₃ and SO₄ concentrations, probably as a result of the effect of increased biological fixation. The As concentration in extracts varied from 8.8 to 15.5 μg/l and was not dependent on the composition of the extracting solution or the addition of barnyard fertilizer.     

改性尿素的肥效及淋溶特性研究初探

在普遍尿素的生产工艺中分别加入一定比例的无机矿物改性剂,研制出３种改性尿素。盆栽结果显示,在等质量及等Ｎ施肥条件下,３种改性尿素均有较大幅度的增产。淋溶实验表明,改性尿素与德国缓释尿素的淋溶曲线相似。     

基于高压电容器振动试验夹具材料的选用与设计

介绍了一种基于高压电容器性能检测及振动试验所需的夹具,从夹具材料的选取、结构设计和刚度要求进行了设计,分析了该夹具在制造过程中存在的关键问题及解决方法,并在振动试验中加以验证。