Utilization and degradation of imazaquin by a naturally occurring isolate of Arthrobacter crystallopoietes

A species of bacteria that is capable of utilizing imazaquin as the sole carbon source was isolated from soil with repeated imazaquin applications, and was identified as Arthrobacter crystallopoietes (designated as strain “WWX-1”). This isolate degrades imazaquin as high as 200 μg ml⁻¹, and the estimated dissipation half-lives increased from 1.51 d for the treatment at 50 μg ml⁻¹ to 4.75 d for 200 μg ml⁻¹. Optimal growth of WWX-1 in mineral salt medium with 50 μg ml⁻¹ imazaquin was obtained at 35 °C and a pH of 5.0. Growth of WWX-1 was also observed in mineral salt medium with the addition of other imidazolinone herbicides such as imazethapyr and imazapyr, but not with different classes of herbicides such as metsulfuron-methyl. Two imazaquin metabolites were detected, and spectral analysis with HPLC–MS, ¹H NMR, and IR revealed one metabolite with a molecular weight (MW) of 199 as quinoline-2,3-dicarboxylic anhydride. We propose that A. crystallopoietes (WWX-1) could serve as an efficient biodegradation system for remediation of water and soils that are heavily contaminated with imazaquin or other structurally similar chemicals.     

超临界CO2回收线路板工艺研究

采用正交试验设计进行了超临界CO₂回收废弃印刷线路板的实验。以温度、压强、时间和夹带剂为实验因素，通过对实验前后样本在重量、厚度、弯曲强度和断裂强度四方面变化的分析考察了各实验因素对实验效果的影响。实验结果表明，影响超临界CO₂法回收印刷线路板的最主要因素为温度、时间和夹带剂，超临界CO₂法回收废弃印刷线路板的最佳工艺条件：温度270℃，压强大于7.38 MPa，时间3 h，夹带剂(水)160 mL。实验进一步验证了压强对实验结果的非显著性影响。     

官地水电站竹子坝料场高边坡的稳定性分析及其影响因数研究

竹子坝料场是官地水电站混凝土浇筑骨料的重要来源之一。结合竹子坝料场的地形地质情况,以及料场开挖后形成的东、南、西三段人工边坡,运用刚体极限平衡的方法进行稳定性分析及其影响因数的研究。     

TiO2-xNx光催化氧化苯甲酸的研究

采用悬浮态光催化反应体系，以氙灯为光源，自制纳米TiO2-xNx为催化剂，考察了苯甲酸光催化氧化过程中TiO2-xNx质量浓度、反应体系初始pH和苯甲酸初始质量浓度对苯甲酸溶液中TOC去除率的影响。实验结果表明：最佳催化剂质量浓度为0．30g／L；TiO2-xNx的等电点为pH=5．3，在酸性条件下（pH=2．0）更有利于苯甲酸在催化剂表面的吸附，以及光生电子与O2反应生成·OH的进行；随苯甲酸初始质量浓度增加，TOC去除率降低，反应速率也相应地降低。TiO2-xNx比P25型TiO2表现出更强的浓度适应能力。     

用灰关联分析和神经网络方法预测煤与瓦斯突出

本文应用灰色系统理论的灰色关联分析,对煤与瓦斯突出影响因素进行灰关联分析,得出了各影响因素对煤与瓦斯突出影响程度的大小排序,选择灰关联分析的五个优势因子:瓦斯放散初速度、坚固性系数、瓦斯压力、煤体破坏类型和开采深度,作为输入参数,用计算机对神经网络编写程序,建立了煤与瓦斯突出预测的神经网络模型.用我国典型突出矿井的煤与瓦斯突出实例作为学习样本,对网络进行训练学习,并以云南恩洪煤矿的煤与瓦斯突出实例作为预测样本进行验证.     

反硝化除磷菌驯化富集方式的探讨

以SBR反应器分别采用一段式和二段式培养方法对反硝化除磷菌进行了驯化富集.结果表明,一段式和二段式培养方法驯化完成后的活性污泥沉降性能均较好,污泥体积指数(SVI)分别约为60、50 mL/g,反硝化除磷菌占聚磷菌的比例达到了77%和71%.两种培养方法下反硝化除磷菌PO3-4-P去除率和脱氮率分别达到了97%和95%以上,缺氧结束时水中PO3-4-P质量浓度小于1 mg/L.驯化完成后污泥的含磷率最高达到了3.7%(质量分数).因此,采用一段式或二段式驯化方法均能实现反硝化除磷菌的有效富集.     

A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test.     

微生物絮凝剂PF-2的成分分析及絮凝机制研究

筛选得到的荧光假单胞菌(Pseudomonas fluorescens)产生的絮凝剂——PF-2在处理高岭土悬浊液时,具有用量少、絮凝效果好等优点,对高岭土悬浊液的絮凝率可达96.5%.呈色反应和紫外扫描的测定结果表明,PF-2大部分为胞外分泌的多糖,含有少量的核酸,提取后每升发酵液可制得絮凝剂粗品2.3 g;ζ电位测定及氢键和离子键检验结果表明,PF-2与高岭土颗粒之间的作用力为离子键;红外光谱扫描分析PF-2中含有O-H、C-H、C＝C和C-O-C等多糖的特征吸收峰;利用扫描电镜观察絮体形态表明,絮体结构密实,其絮凝机制为PF-2和高岭土以离子键的形式结合,之后通过架桥作用絮凝沉淀.     

最优环境税:庇古法则与税制协调

从经济学的角度对国外关于最优环境税的经典理论——庇古法则及近十年来研究的前沿内容——一般均衡模型等作出阐释，并在外部性理论的基础上通过一个一般均衡模型考察环境税的效率特性和在次优情形下最优环境税的决定因素。随后是对我国开征环境税的几点思考：环境税的课征范围应暂定为排放各种废水、废气（烟尘）和固体废弃物的行为。环境税税率的确定可以采用“反复迭代”的方法，即“环境效益优先，兼顾税收协调和收入分配等效应。”其他相关问题的处理，如环境税和其它政策手段的配合使用，环境税税收的使用等。     

自催化法合成聚天冬氨酸

以马来酸酐和乙酸铵为原料，在微波条件下用自催化法合成了聚天冬氨酸（PASP）。通过正交实验确定了最佳合成条件：n（乙酸铵）：n（马来酸酐）=1．2，微波功率为1200W，反应时间为10min。在最佳合成条件下，PASP的收率为91．6％，PASP的黏均相对分子质量约为1．5×10^4。经红外光谱表征和核磁共振氢谱测试结果表明，PASP的各种主要官能团表现明显。当Ca^2＋质量浓度为250mg／L、PASP加入量为3mg／L时，PASP的阻垢率达到95％，表明PASP具有较好的阻垢性能。