营口港辽宁腹地的关联效应分析

在对国内外港口腹地相互关联研究文献综述的基础上,采用灰色关联分析的定量方法对营口港与辽宁腹地2001--2009年的关联效应进行了分析。实证分析表明：港口港城动态关联效应总趋势逐渐增强,但具有明显的阶段性特征;营口港港口区域一体化进程在关联程度较强的基础上不断强化;营口港辽宁腹地关联发展效应演化具有明显的波动性;自然条件与区位、区域设施与交通、经济水平与社会条件是影响营口港辽宁腹地关联度演化的主要因素。为了促进营口港辽宁腹地经济的快速发展,分别从辽宁腹地、营口城市角度提出相关发展建议：进一步加强政府的政策支持;充分利用自主发展和区域合作推进区域发展;集中发展现代服务业,拓展集装箱业务。     

我国副省级城市第三产业发展研究——以哈尔滨为例

第三产业发展水平是衡量一个国家经济实力的重要标准,综合评价第三产业,有助于正确认识我国各地区第三产业的发展水平。以我国15个副省级城市为研究对象,构建第三产业综合发展水平指标体系,运用主成分分析法,通过比较分析得出哈尔滨市第三产业发展中存在的问题,并提出相关对策建议。     

基于排队论的城市垃圾箱最佳间距研究

针对城市垃圾箱最佳间距的研究不够精细的现状,本文通过建立排队论模型得到了可供不同城市参考的城市垃圾箱最佳间距参数表。通过对部分城市街道的垃圾箱摆放间距情况进行实地调查,运用层次分析法将影响垃圾箱间距分布的多重因素转化为单因素;建立了基于指数分布的数学模型,利用排队论分析单因素状态下的垃圾箱间距分布,得到了求解城市垃圾箱最佳间距的一般方法。     

中国与美国对外直接投资区位选择的比较研究

基于邓宁的国际生产折衷理论,对比了中美两国投资规模、空间分布和发展阶段,利用灰色关联分析法比较了影响两国投资区位的因子.结果表明,影响美国对外投资的主要因子是人均GNP、CH和CO2的排放量,影响中国的主要因子是直接投资净流入量、航空运输量和CPI;美国对外直接投资属于市场导向型,而中国尚处于转型期,为对外投资第三阶段.     

高含硫天然气勘探开发潜在危害分析与防范

川东北地区大型天然气矿藏中硫化氢含量较高,且带有高剧毒性和高腐蚀性,勘探开发难度较大。同时气田所处区域的岩土条件十分脆弱,洪涝、大风、冰雹等气候灾害经常发生,易引发泥石流、滑坡,形成地质灾害。另外气田所在地人口密度大,给勘探开发设施布局和居民安全带来很大困难。文章通过对川东北地区天然气勘探、开发过程中存在的潜在危害进行详细分析,提出风险防范技术与对策,以供参考。     

Is Urban Stream Restoration Worth It?1

Kenney, Melissa A., Peter R. Wilcock, Benjamin F. Hobbs, Nicholas E. Flores, and Daniela C. Martínez, 2012. Is Urban Stream Restoration Worth It? Journal of the American Water Resources Association (JAWRA) 48(3): 603-615. DOI: 10.1111/j.1752-1688.2011.00635.x Abstract: Public investment in urban stream restoration is growing, yet little has been done to quantify whether its benefits outweigh its cost. The most common drivers of urban stream projects are water quality improvement and infrastructure protection, although recreational and aesthetic benefits are often important community goals. We use standard economic methods to show that these contributions of restoration can be quantified and compared to costs. The approach is demonstrated with a case study in Baltimore, Maryland, a city with a legal mandate to reduce its pollutant load. Typical urban stream restoration costs of US$500-1,200 per foot are larger than the cost of the least expensive alternatives for management of nitrogen loads from stormwater (here, detention ponds, equivalent to $30-120 per foot of restored stream) and for protecting infrastructure (rip-rap armoring of streambanks, at $0-120 per foot). However, the higher costs of stream restoration can in some cases be justified by its aesthetic and recreational benefits, valued using a contingent valuation survey at $560-1,100 per foot. We do not intend to provide a definitive answer regarding the worth of stream restoration, but demonstrate that questions of worth can be asked and answered. Broader application of economic analysis would provide a defensible basis for understanding restoration benefits and for making restoration decisions.     

Enhanced resistance of yeast mutants deficient in low-affinity iron and zinc transporters to stannous-induced toxicity

Tin or stannous (Sn²⁺) compounds are used as catalysts, stabilizers in plastic industries, wood preservatives, agricultural biocides and nuclear medicine. In order to verify the Sn²⁺ up-take and toxicity in yeast cells we utilized a multi-elemental analysis known as particle-induced X-ray emission (PIXE) along with cell survival assays and quantitative real-time PCR. The detection of Sn²⁺ by PIXE was possible only in yeast cells in stationary phase of growth (STAT cells) that survive at 25 mM Sn²⁺ concentration. Yeast cells in exponential phase of growth (LOG cells) tolerate only micro-molar Sn²⁺ concentrations that result in intracellular concentration below of the method detection limit. Our PIXE analysis showed that STAT XV185-14c yeast cells demonstrate a significant loss of intracellular elements such as Mg, Zn, S, Fe and an increase in P levels after 1 h exposure to SnCl₂. The survival assay showed enhanced tolerance of LOG yeast cells lacking the low-affinity iron and zinc transporters to stannous treatment, suggesting the possible involvement in Sn²⁺ uptake. Moreover, our qRT-PCR data showed that Sn²⁺ treatment could generate reactive oxygen species as it induces activation of many stress-response genes, including SOD1, YAP1, and APN1.     

Degradation of paracetamol by advance oxidation processes using modified reticulated vitreous carbon electrodes with TiO2 and CuO/TiO2/Al2O3

The degradation of paracetamol in aqueous solutions in the presence of hydrogen peroxide was carried out by photochemistry, electrolysis and photoelectrolysis using modified 100 pores per inch reticulated vitreous carbon electrodes. The electrodes were coated with catalysts such as TiO₂ and CuO/TiO₂/Al₂O₃ by electrophoresis followed by heat treatment. The results of the electrolysis with bare reticulated vitreous carbon electrodes show that 90% paracetamol degradation occurs in 4 h at 1.3 V vs. SCE, forming intermediates such as benzoquinone and carboxylic acids followed by their complete mineralisation. When the electrolysis was carried out with the modified electrodes such as TiO₂/RVC, 90% degradation was achieved in 2 h while with CuO/TiO₂/Al₂O₃/RVC, 98% degradation took only 1 h. The degradation was also carried out in the presence of UV reaching 95% degradation with TiO₂/RVC/UV and 99% with CuO/TiO₂/Al₂O₃/RVC/UV in 1 h. The reactions were followed by spectroscopy UV-Vis, HPLC and total organic carbon analysis. These studies show that the degradation of paracetamol follows a pseudo-first order reaction kinetics.     

活性艳橙K-7R分子印迹聚合物微球的制备及结合特性研究

以微米级聚苯乙烯微球为种球,活性艳橙K-7R为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用单步溶胀聚合法在水相中制得了分子印迹聚合物微球(MIPs),并用平衡吸附实验研究了其吸附性能。通过Scatchard分析,结果表明,MIPs在识别K-7R过程中存在两类结合位点,高亲和力结合位点的平衡离解常数Kd1=14.855μmol/L,最大结合量Qmax1=1.282μmol/g;低亲和力结合位点的平衡离解常数Kd2=70.939μmol/L,最大结合量Qmax2=3.930μmol/g。该MIPs对K-7R有较高的亲和性和选择性。