重度富营养化水培条件下烟草的生长特性及其净化效果的研究

研究了烟草在重度富营养化水培条件下的生长特性、根的解剖结构,对其净化效果进行了观测,并对烟草在重度富营养化水中的生长特性变化原因、适应机理进行了探讨。     

广州市不同环境屋顶自然生长的植物多样性分析

通过对广州市不同环境屋顶自然生长的植物进行广泛调查，共记录到维管植物49科109属128种，其中，在污染严重、中等和轻微的环境分别记录到21种、73种和111种。结果表明，植物种类的数量与环境受污染程度成反比，而与周围植物的多少成正比。对植物形态学及生态生物学特征的分析结果表明，屋顶自然生长的植物与地上自然生长的植物相比，植株较矮小，叶片较小，根系较发达，根冠比较大，这是屋顶植物长期适应屋顶特殊环境的结果。通过调查及分析，推荐12种有较好屋顶绿化潜力的植物。     

三维植被网喷播植草技术在高速公路边坡上的应用

三维网喷播植草是一种能在纯石质边坡上进行绿化的新工艺。文章介绍了该技术的施工工艺和质量检验标准，并在广惠高速公路边坡进行应用试验。试验结果表明，该技术绿化防护效果较好，适应当地气候条件。     

花椒农林复合生态系统的简化对某些相关因子的影响

对单一种植和复合种植两种模式的花椒林地(即有草模式和无草模式)进行了相关生态因子的对比调查,以评价现存花椒林单一模式的合理性．结果表明,在单一种植模式下,花椒林的高度、地径和冠幅虽显著优于复合模式,但是病虫害严重;两种模式中土壤含水率均是随土层厚度的增加而增大,但是变幅有较大差异：复合模式的变幅较稳定,为7．59%～23．79％;而单一模式的变化较剧烈,为4．73％～49．72％,复合模式的土壤含水率显著高于单一模式．复合模式的昆虫种类、多样性、丰富度和均匀度也明显高于单一模式,其中单一模式中的肉食性和寄生性昆虫种类低于复合模式,而植食性蚜虫数量则高于复合模式,暗示单一模式中天敌的栖境和资源以及特定的食草昆虫与有益菌缺少．讨论认为,杂草在花椒林生态系统中起着重要的生态作用,现存的单一种植模式虽然对花椒的生长和产量有利,但却是以牺牲农林系统的可持续发展以及生物多样性为代价的．表3参9。     

Entrapment and dissolution of DNAPLs in heterogeneous porous media

Two-dimensional multiphase flow and transport simulators were refined and used to numerically investigate the entrapment and dissolution behavior of tetrachloroethylene (PCE) in heterogeneous porous media containing spatial variations in wettability. Measured hydraulic properties, residual saturations, and dissolution parameters were employed in these simulations. Entrapment was quantified using experimentally verified hydraulic property and residual saturation models that account for hysteresis and wettability variations. The nonequilibrium dissolution of PCE was modeled using independent estimates of the film mass transfer coefficient and interfacial area for entrapped and continuous (PCE pools or films) saturations. Flow simulations demonstrate that the spatial distribution of PCE is highly dependent on subsurface wettability characteristics that create differences in PCE retention mechanisms and the presence of subsurface capillary barriers. For a given soil texture, the maximum and minimum PCE infiltration depth was obtained when the sand had intermediate (an organic-wet mass fraction of 25%) and strong (water- or organic-wet) wettability conditions, respectively. In heterogeneous systems, subsurface wettability variations were also found to enhance or diminish the performance of soil texture-induced capillary barriers. The dissolution behavior of PCE was found to depend on the soil wettability and the spatial PCE distribution. Shorter dissolution times tended to occur when PCE was distributed over large regions due to an increased access of flowing water to the PCE. In heterogeneous systems, capillary barriers that produced high PCE saturations tended to exhibit longer dissolution times.     

The role of interfacial films in the mass transfer of naphthalene from creosotes to water

Viscous, semi-rigid interfacial films that are formed at the interface of certain multi-component non-aqueous phase liquid (NAPLs) and water can significantly reduce the rates of mass transfer of solutes. Creosote-water systems were investigated for their ability to form interfacial films. The effects of these films on the creosote-water partition and on mass transfer of a representative solute, naphthalene, were investigated in a series of experiments. The area-independent mass transfer coefficient of naphthalene contained in creosote decreased by 30% over a 1-week period in systems containing creosote and water. Further aging for up to 21 days did not result in significant additional decreases in the mass transfer coefficient. The creosote-water partition coefficient, however, did not change with extended contact. The presence of viscous interfacial films in creosote-water systems was demonstrated in pendant drop tests. These interfacial films most likely caused the reduction in solute mass transfer coefficients by providing significant resistance to the diffusion of solutes through the interfacial film. Results from mass transfer experiments conducted under different system conditions suggested that hindered diffusion of naphthalene through the bulk creosote phase, changes in composition of creosote as a result of extended dissolution, or changes in creosote-water interfacial area did not contribute to the decrease in naphthalene mass transfer coefficient.     

(<Emphasis Type="Italic">Z</Emphasis>)-9-Pentacosene − contact sex pheromone of the locust borer, <Emphasis Type="Italic">Megacyllene robiniae</Emphasis>

Summary. Male locust borers, Megacyllene robiniae (Förster), responded to females only after contacting them with their antennae, indicating that mate recognition was mediated by a contact sex pheromone. GC-MS analyses of whole-body extracts of males and females determined that the profiles of compounds in the extracts were qualitatively similar, but differed considerably in the ratios of compounds between sexes. Biological activities of reconstructed blends of the most abundant straight-chain (nC₂₃, nC₂₄, nC₂₅, nC₂₆), methyl-branched (3me-C₂₃, 3me-C₂₅), and unsaturated (Z9:C₂₃, Z9:C₂₅, Z9:C₂₇ compounds in extracts from females were assessed in arena bioassays, assessing four distinct steps in the mating behavior sequence of males (orientation, arrestment, body alignment, mounting and attempting to couple the genitalia). Males were unresponsive to freeze-killed, solventwashed females treated with blends of straight-chain and methyl-branched alkanes, but responded strongly to females treated with the blend of alkenes. Further trials determined that the complete sequence of mating behaviors, up to and including coupling the genitalia, was elicited by Z9:C₂₅ alone. Z9:C₂₅ comprised 16.4 ± 1.3% of the total hydrocarbons in whole-body hexane extracts of females and was co-dominant with two other hydrocarbons that were not active. In contrast, in solid phase microextraction (SPME) wipe samples from several areas of the cuticle, Z9:C₂₅ appeared as the single dominant peak, comprising 34.6 – 37.8% of the sampled hydrocarbons. Our data indicate that Z9:C₂₅ is a contact sex pheromone of M. robiniae, being the most abundant hydrocarbon on the surface of the cuticular wax layer of females where it is readily accessible to the antennae of males.     

工业废水和城市污水中邻苯二甲酸酯残留分析

建立了以HLB固相萃取柱和反相液相色谱法测定水体中8种邻苯二甲酸酯的方法,并对方法的回收率、灵敏度进行了评价,同时分析了北京市七类典型污染点源50个采样点位邻苯二甲酸酯的浓度,检出的邻苯二甲酸酯包括DBP、DEHP、BBP、DEP和DCHP,它们的检出率分别为66%、62%、36%、10%和6%,工业废水和城市污水中主要邻苯二甲酸酯残留为DBP和DEHP。检出邻苯二甲酸酯的浓度范围为0.20~848.14μg/L。方法对邻苯二甲酸酯的回收率达到75.1%~115.5%,最低检出限0.10~0.62μg/L。     

川中丘陵区荒坡利用方式对水土流失影响的研究

川中丘陵区荒坡面积占据一定比重,防治水土流失,合理利用荒坡水土资源,对发展本区经济起着重要作用。本文通过网点观测来探求合理利用方式,为荒坡开发利用提供决策依据。     

三氯乙烯在TiO2上光降解反应动力学

设计了新型气固相间歇循环式光催化反应器，选取三氯乙烯为污染物的工作系统进行气固相光催化反应研究．结果表明，在反应器内循环气流量大于３１０ｍＬ／ｍｉｎ时，消除了扩散的影响．当催化剂表面紫外光辐射强度小于０．５ｍＷ／ｃｍ~２和三氯乙烯浓度大于６７μｍｏｌ／Ｌ时．反应处于光子传递控制，光催化反应动力学方程为：ｒ_（ｏｖｅｒａｌｌ）＝１．０８　Ｉ_０．当催化剂表面紫外光辐射强度在０．５－２．０ｍＷ／ｃｍ~２和三氯乙烯初始浓度小于２５．００μｍｏｌ／Ｌ时，反应动力学完全符合Ｌａｎｇｍｕｉｒ－Ｈｉｎｓｈｅｌｗｏｏｄ动力学方程；在紫外光辐射强度大于５ｍＷ／ｃｍ~２和三氯乙烯浓度小于５．２０μｍｏｌ／Ｌ时，光催化反应速率与光强无关，与反应物浓度成正比．光催化反应处于表面作用控制．