加油站油气回收应用问题研究

通过对已进行油气回收改造加油站的现场测试,发现在使用过程中存在的问题,利用软件模拟了卸油及加油油气回收的管道阻力,找出了卸油速度慢及加油油气回收能耗偏高的原因,同时分析了卸油、加油及油气排放处理环节的经济指标,给出了提高加油站油气回收系统效果的建议措施.     

Effect of periphyton community structure on heavy metal accumulation in mystery snail (Cipangopaludina chinensis):A case study of the Bai River, China

The ratio of metal:P stoichiometry was used to identify the accumulation pathways of heavy metals (V, Cr, Co, Ni, Cu, Cd, and Pb) from periphyton to snails Cipangopaludina chinensis Gray (C. chinensis) in the Bai River watershed. The results showed that periphyton communities were mainly composed of two types of algae, filamentous green algae and unicellular diatoms. The proportion of unicellular diatoms in the periphyton community is a key factor that influences metal accumulation in C. chinensis. The V, Cr, Co, Ni, and Cd content of C. chinensis increased steadily as the corresponding metal content of periphyton increased, but Cu and Pb in the snail did not increase in the periphyton. Mechanisms of V, Cr, and Ni accumulation were found to be related to the proportion of diatoms, while Cd and Pb accumulation were dependent on the physiological characteristics of C. chinensis. The accumulation of Cu in C. chinensis was closely related to their grazing behavior. The metal:P stoichiometry revealed that Cr, Ni, and Cd can reduce the potential ecological risks associated with increased P inputs to the ecosystem. V and Co were considered to be relatively safe, regardless of the periphyton P content. Finally, Pb may not be prone to transfer to higher trophic levels, and may pose the lowest ecological risks of the studied heavy metals, but Cu can cause potential ecological risks when eutrophication has occurred.     

如何建立公路声屏障产品质量控制体系

笔者通过对国内公路声屏障产品质量的关注,深入剖析产生产品质量问题的内在原因及外部环境。提出建立公路声屏障产品质量控制体系的思路与实施方法,供大家一起探讨和完善。     

Preparation of FexCe1-xOy solid solution and its application in Pd-only three-way catalysts

FeO_x-CeO₂ mixed oxides with increasing Fe/(Ce+Fe) atomic ratio (1-20 mol%) were prepared by sol-gel method and characterized by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET) and Hydrogen temperature-programmed reduction (H₂-TPR) techniques. The dynamic oxygen storage capacity (DOSC) was investigated by mass spectrometry with CO/O₂ transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO₂ was 5 mol% based on Fe/(Ce+Fe). The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO₂. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO₂ and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment.     

小波奇异性在地震信号去噪中的应用

论文介绍了地震信号的去噪过程中,利用小波良好的时频局部化能力和多分辨率分析能力,对信号进行变换,利用变换后的幅值极大点检测出信号的奇异点(突变点,包含了震相和噪声),继而利用在不同的变换尺度下,震相信号和噪声模极大值的变化特征的不同来去除噪声.利用我台的地震信号进行验证,该方法去噪后震相更清晰,震相的标注信度更高.     

天津滨海盐碱湿地土壤种子库特征研究

对天津滨海新区典型盐碱湿地土壤种子库进行了研究。通过选取三个标准样地进行野外调查,采用种子萌发实验确定土壤种子库的活性、种类及数量;对土壤种子库的物种组成和数量、物种多样性指数、相似性指数及时空分布等特征进行分析,结果表明,滨海新区盐碱湿地土壤种子库共有26植物,种子库的密度在6809～30644粒/m2之间;种子库的生态优势度在0.51～0.81之间,多样性指数相对较低,其中Shannon-Wiener指数最高为1.78;土壤种子库与地面植被之间的相似性指数较低,最低为0.21;种子库的垂直分布特征较为明显,其中0～5cm层种子数量最多,种子数量层间差异显著或极显著;此外,还研究了土壤种子库萌发随时间变化的规律,得出其萌发数量随时间变化的曲线,为今后土壤种子库应用于植被恢复提供了参考。     

环境工程学研究的新思考

本文在环境工程特征分析的基础上,运用现代系统科学原理,以环境理念和工程视角,阐述了环境工程学新领域、新思维和新方法的研究进展,进一步明确了环境工程学在经济社会发展中的重要作用。     

北京市加油站油气回收治理的减排贡献及发展趋势

分析对成品油VOC排放各排放源贡献比率,对北京市显著影响的机动车排放源和加油站排放源贡献比例进行了对比。对油气回收发展趋势进行了简要分析,建议逐步推广ORVR系统,并对加油站油气回收系统的管理提出了建议。     

农业院校环境科学专业学科群建设及课程体系设置

文章以环境科学学科群的带头学科及其内涵、外延分析为基础,对环境科学专业学科群进行了系统分析;并以青岛农业大学环境科学专业课程组织为例,对农业院校环境科学专业学科群建设进行了探讨,为高等学校环境科学专业建设提供一种新范式。     

以高架桥、隧道为枢纽的交通结构震害初探——以立体交通城市重庆为例

以重庆市的地震构造为背景,结合重庆市地震台测震数据阐述了重庆市地震活动情况,介绍了重庆市以高架桥、隧道为枢纽的立体交通方式,分析了各种交通制式在大震下的破坏方式以及破坏程度,针对在建或加固的交通工程提出了建设性意见。