自然状态下树木排放N2O的研究

大气中主要温室气体之一N₂O的部分来源尚不清楚,以前认为只有土壤微生物过程是N₂O的生物源,本文则旨在证明自然状态下植物也是N₂O的排放源.采用同步空气样品采集装置和气相色谱仪观测了长白山阔叶红松林内空气N2O的垂直分布特征,发现林冠或其附近处出现高N₂O浓度,高N₂O浓度比同一时刻其他高度处的正常N₂O浓度高3.03%～64.9%,差异显著或极显著.在林冠高度处的高N₂O浓度和树干高度处的正常N₂O浓度同时存在的现象证明了植物向外排放N₂O,即植物自身在自然状态下是N2O的一个排放源.     

湿地植被叶面积指数对光化学指数和光能利用率关系的影响————基于实测数据和PROSPECT-SAIL模型

光化学指数PRI(Photochemical Reflectance Index)是估算光能利用率LUE(Light Use Efficiency)的一种快速监测的有效指标,分析各种因素对二者的影响是提高估算精度的前提.论文针对三种杭州湾典型湿地植物 [旱柳(Salix matsudana),柽柳(Tamarix chinensis)和芦苇(Phragm itescommunis)],实地观测了其光合作用及日变化,叶面积指数以及同步植被光谱.同时采用PROSPECT-SAIL模型模拟叶面积指数LAI(Leaf Area Index)从小到大变化时植被冠层反射率,分析LAI的变化对冠层PRI的影响.结果表明:1)三种植被在日变化上,芦苇,旱柳和柽柳的PRI和LUE的相关性较好,R²分别为0.581 6,0.524 6和0.514 6;而对同一种植被在不考虑时间变化的条件下,PRI和LUE的相关性会有所减弱,对于LAI较小的冠层,PRI不能精确反映LUE;2)当LAI < 5时,冠层下土壤背景对冠层PRI影响较大,在不同土壤背景下,土壤亮度低的对冠层PRI影响较小;3)当LAI > 5时,土壤背景对冠层PRI影响较小,冠层自身的LAI才是影响PRI和LUE相关性的决定因素.因此,PRI和LUE关系模型还需要进一步探索和完善,引入更精确的模型和参数,不断提高LUE估算的准确度.     

紫外线辐射对小麦和燕麦竞争性平衡的影响--小麦和燕麦生物量结构与冠层结构

在模拟１５％臭氧层减薄条件下讨论了紫外线辐射增强对大田中小麦和燕麦在单独种植与混合种植时的生物量结构和冠层结构的影响。紫外辐射使两物种的生物量减少，使节间缩短，叶片着生高度下降，但使根冠比和单株有效穗数增加。两物种在单种和混种时对紫外辐射的反应有所不同，种间竞争有时加强紫外辐射的影响，但有时则又能抵消其作用。紫外辐射使竞争性平衡向有利于小麦的方向发展，这一改变可以部分地由两物种的生物量及冠层结构对     

鲁西南粮棉产区生态控制农田害虫技术研究

根据生态类型区的农业生态现状，以种植结构调整为基础，发挥生态因素控制害虫作用为重点，充分利用害虫天敌，生物制剂的控害作用，必要时辅以化学防治调节，达到生态控制农作物害虫的目的。     

新型多胺螯合纤维的合成及纤维过滤器的研究

用棉纤维和三乙烯四胺为原料,以对二苯甲酰氯为交联剂,合成了新型多胺螯合纤维(CC-TC-TETA),并用红外(FT-IR)对其表征。用此合成纤维为滤料,探讨纤维过滤器运行参数:过滤速度,反冲洗模式与反冲洗强度,实验证明:进水口压力为0.60MPa,进水流速为25m·h-1时,采用0.1%HNO3为冲洗液,冲洗空气压力为0.05MPa,冲洗液流速为20m·h-1,混合冲洗时间为40min时出水水质最佳。该项研究将在水深度处理方面具有良好的应用前景。     

生化—物化组合工艺处理棉浆粕生产综合废水

棉浆粕生产综合废水的生化—物化处理试验表明，采用驯化活性污泥法可有效地去除废水中易生物降解的有机物。当浆粕废水进水ＣＯＤｃｒ浓度１２００～１８００ｍｇ／Ｌ范围内，ＣＯＤｃｒ负荷１．８～２．８ｋｇ／ｍ３·ｄ时，ＣＯＤｃｒ去除率可达５８％～６４％，ＢＯＤ５去除率可达８５％～８９％。生化出水经投加化学混凝剂进行物化处理后，ＣＯＤｃｒ可进一步去除６５％～７５％左右，可满足排放标准的要求     

A Fine-Scale <Emphasis Type="Italic">k</Emphasis>−ε Model for Atmospheric Flow over Heterogeneous Landscapes

A multi-purpose model for small-scale atmospheric flows over heterogeneous landscapes is being developed. The aim of this research is to build a tool able to predict the dynamical (wind, turbulence) and diffusive (gases, particles) fields over landscapes characterised by heterogeneous plant cover. In its present stage of development the model is based on the numerical integration of neutral atmospheric flow equations, using an energy-dissipation closure scheme and over a domain that may include vegetation layers. Three validation cases of the model are presented: (i) response of the airflow to a change in surface roughness; (ii) airflow within and above a horizontally homogeneous plant canopy; (iii) airflow over two complex forest-to-clearing and clearing-to-forest transitions. All simulations provide results in good agreement with the experimental data, except for turbulent kinetic energy just after a clearing-to-forest transition. This result is not surprising for a statistical k– model in a flow region characterised by strong distorsion and intermittent turbulence. However the overall good performance of the model is promising for environmental research at fine scales over heterogeneous landscapes.     

天然蛋白杂化硅溶胶阻燃棉织物的制备及燃烧性能分析

采用溶胶-凝胶法,以正硅酸乙酯(TEOS)为前驱体、乙醇(C_2H_5OH)为溶剂、盐酸(HCl)为催化剂,1-γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)为偶联剂制备SiO_2单一、复合和明胶(C_(102)H_(151)O_(39)N_(31))杂化溶胶,利用激光粒度仪对溶胶粒径进行测定。采用浸渍-烘焙过程将溶胶后整理棉织物。利用热重分析(TG)、极限氧指数(LOI)、扫描电镜(SEM)、X射线光电子能谱(XPS)、傅里叶变换红外光谱分析(FTIR)对整理前后棉织物热解特性、阻燃性能、表面微观形貌、表面元素组成和官能团分布进行测试和表征,探讨明胶杂化溶胶阻燃效应和机理。结果发现:溶胶粒径分布表明纳米SiO_2-KH570-明胶之间发生了化学键紧密结合,缩合生成Si-O-Si和氢键;SEM、FTIR和XPS分析表明具有明胶杂化组分的硅基溶胶在织物表面形成紧密涂层,呈现一定化学结合状态;TG分析表明,该结合状态对热稳定性影响显著,杂化溶胶后整理织物热解残炭率较原始棉织物提高872%,SiO_2-KH570和SiO_2-明胶复合溶胶体系间存在协效性;LOI分析表明,SiO_2-KH570-明胶杂化溶胶阻燃效应最佳,LOI最高为25.2,对应ΔLOI/Δm最高为4.80 g~(-1),SiO_2单一溶胶和明胶及SiO_2-KH570复合溶胶和明胶间体现明显协同效应;明胶可单方面提升SiO_2单一溶胶及SiO_2-KH570复合溶胶的凝胶化效应,促进三维微观骨架涂层结构形成,提升燃烧过程中棉织物脱水成炭作用。     

The Structure of the Shear Layer in Flows over Rigid and Flexible Canopies

Flume experiments were conducted with rigid and flexible model vegetation to study the structure of coherent vortices (a manifestation of the Kelvin–Helmholtz instability) and vertical transport in shallow vegetated shear flows. The vortex street in a vegetated shear layer creates a pronounced oscillation in the velocity profile, with the velocity near the top of a model canopy varying by a factor of three during vortex passage. In turn, this velocity oscillation drives the coherent waving of flexible canopies. Relative to flows over rigid vegetation, the oscillation in canopy geometry has the effect of decreasing the amount of turbulent vertical momentum transport in the shear layer. Using a waving plant to determine phase in the vortex cycle, each vortex is shown to consist of a strong sweep at its front (during which the canopy is most deflected), followed by a weak ejection at its rear (when the canopy height is at a maximum). Whereas in unobstructed mixing layers the vortices span the entire layer, they encompass only 70% of the flexibly obstructed shear layer studied here.