臭氧与TiO2/UV协同降解对氯苯酚

利用O3／UV、TiO2／UV和O3／TiO2／UV降解对氯苯酚表明，臭氧与TiO2／UV具有明显的协同作用，如在本实验条件下降解5min后，上述3者对对氯苯酚的去除率分别为55％、10％和77%。O3／TiO2／UV协同作用的本质是由于臭氧能带走二氧化钛光致电子空穴对中的电子，从而产生了更多的羟基自由基，加速了有机物的降解。     

Induced alkoxyresorufin-O-dealkylases in tilapias (Oreochromis niloticus) from Guandu river, Rio de Janeiro, Brazil

The activity of fish monooxygenases has been extensively used as a monitoring tool to detect contamination of water bodies by cytochrome P450-inducing agents. In this study we evaluated the activities of ethoxy- (EROD), methoxy- (MROD) and pentoxy- (PROD) resorufin-O-dealkylases in the liver of Nile tilapias (Oreochromis niloticus) collected at the Guandu river, at a reference clean site (Lake 1) and at two other sampling sites (Lakes 2 and 3) in Rio de Janeiro state, Brazil. Alkoxyresorufin-O-dealkylases were measured fluorimetrically in the hepatic S9 fraction. EROD (17.7-fold), MROD (14.2-fold) as well as PROD activities were considerably higher in tilapias from Guandu river. A moderate increase of EROD (5.0-fold) and MROD (5.4-fold) was also found in tilapias from Lake 3. These findings suggest that Guandu river watershed, the main source of urban drinking water supply in Rio de Janeiro, is polluted with CYP1A-inducing xenobiotics. Furthermore, we also found a good linear relationship between EROD and MROD, a finding that agrees with the hypothesis that the two reactions are catalysed by the same CYP1A isoform in O. niloticus.     

Degradation of Benzo[a]Pyrene in Soil with Arbuscular Mycorrhizal Alfalfa

Mycorrhizal and non-mycorrhizal alfalfa (Medicago sativa) was grown in pots containing soil artificially contaminated with various levels of benzo[a]pyrene (B[a]P)(0, 1, 10 and 100 mg kg^–1). Soil and plants were sampled after 30, 40, 50, 60 and 90 days and compared with unlanted pots. The percentage of mycorrhizal root length colonized by Glomus caledoniun was not significantly affected by the addition of B[a]P up to 10 mg kg^–1 but was significantly lower at 100 mg kg^–1B[a]P compared with low concentrations (p < 0.05). There was no difference in soil polyphenol oxidase and dehydrogenase activity among the controls and applications of 1 and 10 mg kg^–1 of B[a]P. However, enzyme activities were significantly higher at 100 mg kg^–1B[a]P compared with the other three treatments, and there was no mycorrhizal effect. Over a period of 90 days the concentration of B[a]P in soil in which alfalfa was grown was significantly lower than in unplanted soil (p < 0.05). Degradation rates of B[a]P added at 1, 10 and 100 mg kg^–1 without G. caledonium were 76, 78 and 53%, and with mycorrhizal inoculation were 86, 87 and 57%. The degradation rate in unplanted soil was significantly lower than in planted soil, and was significantly higher in medium- and low-B[a]P treatments than in the high B[a]P concentration tested. There is a possibility of enhancement phytoremediation of PAHs in rhizosphere soil with arbuscular mycorrhizal fungi.     

光(温)敏核不育水稻生态及生理生化研究概述

本文介绍了光、温敏核不育水稻在生态及生理生化方面取得的主要成就.着重概述了光、温敏核不育水稻雄性育性转换的光温生态条件,育性转换过程中蛋白质、氨基酸、酶活性、ATP及内源植物激素持续变化.另外,对光、温敏不育水稻研究存在的问题进行了分析.     

富营养化水体中藻类生长限制因素的确定及其应用

在富化营养化的巢湖，围隔实验结果表明磷和其它营养元素不是水体藻类的生长限制因素、藻类生长的正磷酸盐阈值浓度为０．０１９ｍｇ／ｌ，它低于巢湖实际浓度。湖水的矿物性浊度很高，净生产力在一米水深以下呈现负值，数据表明学强在大数时间是藻类生长的限制因素。在巢湖治理过程中，需大幅降低流域内的磷负荷，使湖水平均溶解态总磷浓度从目前的０．０４９ｍｌ／ｌ降到０．０１９ｍｇ／ｌ以下。因此巢湖在治理和恢复是一个缓慢的     

用~(32)P后标记法检测贝类鳃中的DNA加合物

建立了用~（３２）Ｐ后标记技术检测ＤＮＡ加合物的方法，研究了不同水质海湾的贝类鳃中ＤＮＡ加合物水平同时测定了除鳃外贝的其他软组织中多环芳烃（ＰＡＨｓ）的含量．结果表明，软组织中ＰＡＨｓ含量低的贝其鳃中加合物水平比ＰＡＨｓ含量高的贝的加合物水平低，即ＤＮＡ加合物水平与贝组织中ＰＡＨｓ含量有关．     

某型飞机尾翼前缘不同构型抗鸟撞计算与试验分析

目的通过不同构型的抗鸟撞研究,找到满足25.631[1]条吸能最好的尾翼前缘构型。方法结合某型民机尾翼前缘结构设计,规划了3种构型6种方案进行优选,分析中,鸟体采用SPH光滑粒子,金属材料则考虑了不同应变率下的动态力学性能,对其进行了结构动力学鸟撞冲击仿真分析,并同选型研发试验的结果进行了对比。结果仿真与试验结果一致,吻合度较高,结合吸能情况,选择最佳的前缘布置方案。结论验证了仿真分析手段的合理可靠性,并且在构型优化过程中得到最佳设计方案。     

改性膨润土对杭州西湖沉积物各形态磷的吸附性能

通过盐酸、碳酸钠、高温焙烧及复合改性等多种改性方法对膨润土进行改性,并借助扫描电子显微镜、傅里叶红外光谱仪及X射线衍射仪等仪器对其进行表征,探讨最佳的改性方法.结果表明,10%碳酸钠+450℃高温焙烧复合改性膨润土(Modified bentonite,MB)为最佳改性用土.对比改性前后膨润土颗粒对沉积物各形态磷吸附性能,发现MB颗粒对沉积物磷吸附性能优于膨润土原土(raw bentonite,RB)颗粒.在最佳动态吸附条件下,RB对沉积物TP、OP、IP、Fe/Al-P和Ca-P的吸附率分别为32.5%、25.4%、52.6%、34.6%和12.4%;MB对沉积物TP、OP、IP、Fe/Al-P和Ca-P的吸附率分别为35.5%、29.1%、54.5%、44.6%和10.7%.静态吸附实验结果表明:RB颗粒和MB颗粒在静态吸附时间为28 d时,对沉积物TP的吸附量分别为828.2 mg·kg~(-1)和977.2 mg·kg~(-1),相应的吸附率分别为58.2%和68.6%.MB对沉积物磷的吸附性能较好,可进一步用于富营养化湖泊沉积物磷控制.     

TiO2表面沉积Ag粒子及其可见光下降解含盐废水中的苯酚

为了制备可见光激发下能高效降解含盐废水中有机物的光催化剂,首次以商用TiO_2光催化剂(P25)为载体,利用吸附相反应技术一步获得了Ag沉积的可见光响应复合光催化剂.同时,通过XPS、TEM、HRTEM及紫外可见漫反射光谱图,结合多种高含盐水体系中苯酚的光催化降解过程,研究了不同Ag沉积对催化剂可见光活性的影响.结果发现,吸附平衡后P25表面富含水的吸附层可作为反应和粒子的生成场所,生成量子尺寸的Ag粒子.另外,在吸附层中生成的Ag粒子均匀分布于P25表面并与之紧密结合,并在TiO_2晶格结构中引入晶格交错结构.Ag与TiO_2的表面等离子体共振效应和晶格交错结构共同提升了催化剂的可见光响应和电荷的分离效率,增强了催化剂对苯酚的可见光催化性能.在含盐废水体系中,盐离子数量越多,催化剂在可见光下降解苯酚过程受到的干扰越大.     

Relationship between metabolic enzyme activities and bioaccumulation kinetics of PAHs in zebrafish (Danio rerio)

Many studies have investigated bioaccumulation and metabolism of polycyclic aromatic hydrocarbons (PAHs) in aquatic organisms. However, lack of studies investigated both processes simultaneously, and the interaction between these two processes is less understood so far. This study investigated the bioaccumulation kinetics of PAHs and metabolic enzyme activities, including total cytochrome P450 (CYPs) and total superoxide dismutase (T-SOD), in zebrafish. Mature zebrafish was exposed to the mixture of phenanthrene and anthracene under constant concentration maintained by passive dosing systems for 16 days. The results showed that PAH concentrations in zebrafish experienced a peak value after exposure for 1.5 days, and then decreased gradually. The bioaccumulation equilibrium was achieved after exposure for 12 days. Both of the uptake rate constants (k_u) and the elimination rate constants (k_e) decreased after the peak value. The variation of PAH concentrations and metabolic enzyme activities in zebrafish had an interactive relationship. CYPs and T-SOD activities increased initially with the increase of PAH concentrations, but decreased to the lowest state when PAH concentrations reached the peak value. When the bioaccumulation equilibrium of PAHs was achieved, CYPs and T-SOD activities also reached the steady state. In general, CYPs and T-SOD activities were activated after exposure to PAHs. The decrease of PAH concentrations in zebrafish after the peak value may be attributed to the great drop of k_u and the variation of CYPs activities. This study suggests that an interactive relationship exists between bioaccumulation kinetics of PAHs and metabolic enzyme activities in aquatic organisms.