Photodegradation of Oryzalin in aqueous isopropanol and acetonitrile

The phototransformation of Oryzalin was studied under UV light (λ_max ≥ 290 nm) and sunlight (λ_max ≥ 250 nm) in aqueous isopropanol and acetonitrile solution in absence and presence of TiO₂ as sensitizer. The rate of photodegradation of Oryzalin in different solvent system followed first-order kinetics, and calculated half-lives were found to be in the range of 23.52-53.75 h for UV light and 41.23-61.43 h for sunlight. From this study, total 12 photoproducts were identified and characterized on the basis of column chromatography and Q-Tof micromass spectral data. The plausible mechanism of phototransformation involved was hydrolysis, breaking of sulfonic bond, and loss of amino and sulfonic acid group.     

光照条件对跑道池光生物反应器内蛋白核小球藻生长特性的影响

本文采用多孔曝气管的曝气方式,以蠕动泵为藻液循环的动力,研究了气体流量、光照强度、光照周期等因素对跑道池光生物反应器内蛋白核小球藻生长与代谢特性的影响,并利用傅里叶红外光谱半定量法对不同光照条件下藻细胞内蛋白质、油脂以及多糖含量变化进行了分析。研究结果表明,适当的气体流量、光照强度和光照周期有利于跑道池内蛋白核小球藻细胞的生长和代谢。在本实验条件下,在最佳气体流量2 000 m L/min条件下,光照强度为3 500μW/cm2,光照周期为16∶8时最有利于蛋白核小球藻的生长;光照强度为2 000μW/cm2和光照周期为16∶8的条件均有利于藻细胞内油脂的积累。     

臭氧法对酸性嫩黄G溶液的脱色效率和残留物的分析

实验考察了臭氧对酸性嫩黄G色度脱除和其溶液pH值的变化情况,并对降解溶液中的残留物进行定量分析。结果发现,20min时,脱色率达到97.5%;有酸性物质生成并使得溶液的pH值随反应时间的推移下降,pH与脱色率总体变化趋势一致。经反应,分子中的—SO3Na基团大部分生成了SO42-;N并没有氧化成NO2-、NO3-,而是生成其它含N化合物。     

模拟可见光下土壤表面石油的光化学降解研究

在模拟可见光照射下,分析了土壤中的初始含油量、土壤类型和土壤pH值对石油在土壤表面光降解过程的影响,并利用紫外-可见分光光度法(UV-Vis)、气相色谱-氢火焰离子化检测器(GC-FID)和傅立叶红外光谱(FTIR)等方法对石油在光降解过程中的演变规律进行研究.结果表明,石油在土壤表面上的光化学降解行为符合准一级反应动力学,实验测得石油的光解速率常数为0.002 6～0.017 2 h^-1,半衰期为40～267 h.GC-FID分析结果表明,在光降解50 h后,石油的饱和烃组分中高碳数的烷烃相对含量降低,低碳数的烷烃相对含量提高;芳香烃组分的大部分色谱峰有明显地降低或消失.红外光谱分析发现,光照60 h后土壤萃取液中可能产生了羰基类化合物,说明石油在光降解过程中逐渐发生氧化.     

用环己烷氧化副产物制备浮选剂

在固体酸催化剂作用下,用环己烷氧化制备环己酮的副产物——酸性油和轻质油进行酯化反应,制备了羧酸混合酯,酯化反应的最佳工艺条件：n（C4-C5醇）：n（有机羧酸）=1．2：1,催化剂质量分数为1．5％,反应温度为110-160℃,反应时间为5h。经应用评价结果表明,该羧酸混合酯是一种性能优异的选煤浮选剂。     

Fe^3＋掺杂TiO2/凹凸棒复合材料的光催化性能

采用酸催化的溶胶-凝胶法制备了一系列Fe^3＋掺杂TiO2/凹凸棒（Fe^3＋-TiO2/ATP）复合光催化剂材料。在可见光条件下,以亚甲基蓝（MB）溶液的光催化降解反应,评价了样品的光催化性能,研究了TiO2负载量、Fe^3＋掺杂量和焙烧温度对复合材料光催化性能的影响。在单因素实验的基础上,采用正交实验设计（L25（53））优化了催化剂的制备条件。光催化实验结果表明,MB在复合材料上的光催化降解反应遵循Langmuir-Hinshelwood（L-H）动力学模型。正交实验结果表明,当TiO2负载量为15%、Fe^3＋掺杂量为0.5%和焙烧温度为550℃时,得到的复合材料对MB的光催化降解效率最佳,测得表观反应速率常数kapp为6.09×10^-3min^-1,反应4 h后MB的降解率（Dt）可达75.88%,相同实验条件下与P25（1.51×10^-3min^-1）相比较,反应速率提高了4.03倍,降解率提高了45.05%。另外,复合材料的沉降性能优于P25,易于分离,是一类有应用前景的复合光催化剂。敏世雄王芳魏立强王永生冯雷佟永纯韩玉琦     

Combining a finite mixture distribution model with indicator kriging to delineate and map the spatial patterns of soil heavy metal pollution in Chunghua County, central Taiwan

This study identifies the natural background, anthropogenic background and distribution of contamination caused by heavy metal pollutants in soil in Chunghua County of central Taiwan by using a finite mixture distribution model (FMDM). The probabilities of contaminated area distribution are mapped using single-variable indicator kriging and multiple-variable indicator kriging (MVIK) with the FMDM cut-off values and regulation thresholds for heavy metals. FMDM results indicate that Cr, Cu, Ni and Zn can be individually fitted by a mixture model representing the background and contamination distributions of the four metals in soil. The FMDM cut-off values for contamination caused by the metals are close to the regulation thresholds, except for the cut-off value of Zn. The receiver operating characteristic (ROC) curve validates that indicator kriging and MVIK with FMDM cut-off values can reliably delineate heavy metals contamination, particularly for areas lacking background information and high heavy metal concentrations in soil.     

环境规制对区域技术创新影响的门槛效应

实现环境规制和经济增长之间"双赢"的关键在于环境规制能否促进企业技术创新。本文在环境规制强度和企业技术创新之间构建了数理模型,并基于区域异质性假定检验了我国环境规制与技术创新的非线性关系并确定了环境规制的最优规制水平。研究表明:环境规制强度与技术创新是非线性的。在强度维度上,环境规制强度和企业技术创新之间符合"U"型关系,即随着环境规制强度的由弱变强,对企业技术创新产生先降低后提高的影响。环境规制的创新效应还取决于经济发展水平的变量。经济发展水平则存在双门槛,经济发展水平跨越的门槛值越高,环境规制对技术创新的促进作用越显著。本文政策涵义明显:政府切忌走入盲目提高环境规制强度的误区,应根据各区域现实特点,有针对性地制定差异化的环境规制强度和标准,并注重滚动修订,及时调整至最优水平。     

Cascade-based attack vulnerability on the US power grid

The vulnerability of real-life networks subject to intentional attacks has been one of the outstanding challenges in the study of the network safety. Applying the real data of the US power grid, we compare the effects of two different attacks for the network robustness against cascading failures, i.e., removal by either the descending or ascending orders of the loads. Adopting the initial load of a node j to be L_j=[k_j(Σ_mΓjk_m)]^α with k_j and Γ_j being the degree of the node j and the set of its neighboring nodes, respectively, where α is a tunable parameter and governs the strength of the initial load of a node, we investigate the response of the US power grid under two attacks during the cascading propagation. In the case of α<0.7, our investigation by the numerical simulations leads to a counterintuitive finding on the US power grid that the attack on the nodes with the lowest loads is more harmful than the attack on the ones with the highest loads. In addition, the almost same effect of two attacks in the case of α=0.7 may be useful in furthering studies on the control and defense of cascading failures in the US power grid.