利用δ18O信息分析冬小麦对浅埋深地下水的利用

黄河下游引黄灌区地下水埋深通常较浅,冬小麦生长季存在对地下水的利用,论文应用稳定同位素方法研究冬小麦对地下水的利用特征。在中国科学院禹城综合试验站开展实验,通过分析不同灌溉处理条件下土壤水和植物茎水δ¹⁸O值之间的关系,应用同位素线性混合模型估算了冬小麦不同生育期对地下水的利用比例。研究结果表明,水的¹⁸O信息能很好地揭示冬小麦对不同层次土壤水的利用特征,雨养处理,40%田间持水量处理和现行灌溉制度处理下冬小麦在返青后对地下水的利用分别占其总耗水量的28%,22%和4%左右。研究结果显示适度的灌溉有利于促进作物对不同层次土壤水分的稳定利用,而现行的大田灌溉方式则抑制了作物对地下水资源的利用。     

九黄环线旅游可持续发展现状研究

通过对九黄环线旅游业在可持续发展道路上面临的积极因素及不利因素的分析，探讨了九黄环线旅游业可持续发展现状。以可持续发展理念为指导，提出了九黄环线旅游可持续发展目标，以及进一步做好环线线路规划建设、加大可持续发展宣传力度、加强旅游管理、增强族游可持续环境保护等具体措施，进一步明确了九黄环线旅游业可持续发展的建设方向。     

Pyrolysis of low-density polyethylene using synthetic catalysts produced from fly ash

Catalytic pyrolysis of low-density polyethylene (LDPE) was investigated using various fly ash-derived silica–alumina catalysts (FSAs). FSAs were prepared by a simple activation method that basically includes NaOH treatment of fly ash by a fusion method, followed by an aging process. A series of LDPE pyrolysis experiments was conducted and the catalytic performance of FSAs was assessed in terms of the degradation temperature and the simulated boiling point distribution of the liquid products. The effects of synthesis conditions such as NaOH/fly ash weight ratio and aging time were examined by X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET) surface area analyzer, and scanning electron microscope to clarify the controlling factors affecting the catalytic activity. To obtain catalyst with high activity, it is necessary to produce sufficient silica and alumina species that can be easily co-precipitated into solid acid catalyst by destruction of the fly ash structure and to optimize the activation time for catalyst synthesis to prevent the transformation into inactive phases. The catalytic performance of FSA obtained from optimal conditions was equivalent to that of commercial catalysts, demonstrating the effectiveness of the catalyst.     

河滩人工湿地对河流洪水位影响的数值模拟

运用计算水力学的基本理论，采用二维水流数学模型进行河流泄洪能力的数值模拟，借助于SMS地表水软件，分别模拟了河流在不同湿地面积、湿地宽度及不同植物糙率条件下，河流洪水位的抬升情况。结果表明，不同湿地宽度对泄洪水位的影响，最终归结为主槽宽度的变化对泄洪水位的影响。主槽宽度相对于湿地面积及植物糙率，对洪水位的抬升影响较大，且主槽宽度越小，水位涨幅越大。对于在河流中如何布置和种植人工湿地及湿地植物的选取具有一定的指导作用。     

影响土壤电动力学修复技术的主要因素

综述了影响土壤电动修复的几个主要因素，如土壤的pH值、Zeta电位、极化问题、化学性质以及含水率等等，并提出了一些可行性解决措施。如能解决好这几个问题，必将加速土壤电动修复的研究进展。     

Adsorption of soluble oil from water to graphene

The toxicity of soluble oil to the aquatic environment has started to attract wide attention in recent years. In the present work, we prepare graphene according to oxidation and thermal reduction methods for the removal of soluble oil from the solution. Characterization of the as-prepared graphene are performed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectra, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, and contact angle analysis. The adsorption behavior of soluble oil on graphene is examined, and the obtained adsorption data are modeled using conventional theoretical models. Adsorption experiments reveal that the adsorption rate of soluble oil on graphene is notably fast, especially for the soluble diesel oil, which could reach equilibrium within 30 min, and the kinetics of adsorption is perfectly consistent with a pseudo-second-order model. Furthermore, it is determined that the adsorption isotherm of soluble diesel oil with graphene fit the Freundlich model best, and graphene has a very strong adsorption capacity for soluble diesel oil in the solution. These results demonstrate that graphene is the material that provided both good adsorptive capacity and good kinetics, implying that it could be used as a promising sorbent for soluble oil removal from wastewater.     

Biodegradation of pendimethalin by Bacillus subtilis Y3

A bacterium strain Y3,capable of efficiently degrading pendimethalin,was isolated from activated sludge and identified as Bacillus subtilis according to its phenotypic features and 16 S rRNA phylogenetic analysis.This strain could grow on pendimethalin as a sole carbon source and degrade 99.5%of 100 mg/L pendimethalin within 2.5 days in batch liquid culture,demonstrating a greater efficiency than any other reported strains.Three metabolic products,6-aminopendimethalin,5-amino-2-methyl-3-nitroso-4-(pentan-3-ylamino) benzoic acid,and 8-amino-2-ethyl-5-(hydroxymethyl)-1,2-dihydroquinoxaline-6-carboxylic acid,were identified by HPLC-MS/MS,and a new microbial degradation pathway was proposed.A nitroreductase catalyzing nitroreduction of pendimethalin to 6-aminopendimethalin was detected in the cell lysate of strain Y3.The cofactor was nicotinamide adenine dinucleotide phosphate(NADPH) or more preferably nicotinamide adenine dinucleotide(NADH).The optimal temperature and pH for the nitroreductase were 30℃ and 7.5,respectively.Hg~(2+),Ni~(2+),Pb~(2+),Co~(2+),Mn~(2+) Cu~(2+),Ag~+,and EDTA severely inhibited the nitroreductase activity,whereas Fe~(2+),Mg~(2+),and Ca~(2+) enhanced it.This study provides an efficient pendimethalin-degrading microorganism and broadens the knowledge of the microbial degradation pathway of pendimethalin.     

The effects of perceived organizational support,perceived supervisor support and perceived co-worker support on safety and health compliance

Although knowledge is cumulating, very little is known about the effects of various sources of support on safety and health compliance. This study goes beyond previous research by investigating the relationships among perceived support from organizations, supervisors and co-workers, and employees’ safety and health compliance behaviour at chemical and petroleum process plants. The results of this study show that the support from organizations, supervisors and co-workers was significantly related to employees’ safety and health compliance. Also, the findings reveal that perceived supervisor support has the strongest influence in ensuring employees’ safety and health compliance behaviour.     

胶州湾大沽河河口表层沉积物中多环芳烃分布特征、来源及生态风险评价

对胶州湾大沽河河口18个站点处表层沉积物中多环芳烃的含量及其分布特征进行研究,并对其来源进行解析以及潜在风险展开评价。研究表明,大沽河河口表层沉积物中所测得的16种优先控制的多环芳烃总量为21.93×10-9~634.64×10-9,平均含量为239.41×10-9,根据沉积物中PAHs污染等级划分,大沽河河口PAHs污染状况属于中度污染,且7月份PAHs含量高于10月份。所有站点中16种PAHs平均含量最高的前三位分别为芴（58.10×10-9）、荧蒽（28.71×10-9）、芘（23.69×10-9）,含量最低的为苊（0.65×10-9）。同时与国内外多个海湾河口表层沉积物中多环芳烃污染状况比较,大沽河河口表层沉积物中多环芳烃污染状况处于中等水平,应引起注意。运用特征比值法及主成分分析法对研究区多环芳烃来源进行解析,显示大沽河河口表层沉积物中多环芳烃来源主要为机动车尾气排放及化石燃料等燃烧而产生的石油燃烧源及原油等直接泄漏导致的石油源。采用效应区间低、中值法（ERL/ERM）对大沽河河口表层沉积物中的多环芳烃进行生态风险评价,仅个别站点芴含量超出效应区间低值（ERL）,其余站点PAHs含量均在ERL值以下,对生态环境潜在负面效应很小。根据苯并（a）芘的等效致癌毒性（BEQ）评价发现大沽河河口表层沉积物中PAHs对人体健康不存在威胁。     

饮用水源地浮游藻类群落特征及富营养化风险评价

为了解新立城水库藻类分布及富营养化特征,于枯水期和丰水期进行调查与分析,结果表明,新立城水库共鉴定出藻类29种,隶属于绿藻门、蓝藻门、硅藻门、隐藻门、金藻门、裸藻门和甲藻门共7门19科,其中绿藻门最多,通过生物多样性指数分析得到,枯水期水质优于丰水期;分析近10年水库水体理化性质得到水库总体上呈轻度富营养化状态,氮磷浓度较高,农业面源污染是导致水体中氮磷浓度偏高的主要原因。