钢桁架-钢筋混凝土管柱结构风参数试验研究

结构下部空旷,上部挡风墙承担的风荷载对结构下部产生较大作用。我国规范没有对该类结构及其顶部透气性A型架的风参数作具体规定。为解决工程设计中风参数取值问题,进行了刚性模型风洞试验研究,得到了不同工况下挡风墙、A型架、管柱的体型系数及挡风墙的阵风系数,分析了风机、周围建筑物、风向角对相关风参数的影响,给出了相关参数的建议值。并将试验结果与数值模拟计算结果进行了对比分析,结果表明,二者吻合较好,研究结果为工程设计提供了基础资料,可供同类工程参考。     

Sorption of tylosin on clay minerals

The equilibrium sorption of tylosin (TYL) on kaolinite and montmorillonite was measured at different solution pH using batch reactor systems. The results showed that all the sorption isotherms were nonlinear and that the nonlinearity decreased as the solution pH increased for a given clay. At a specific aqueous concentration, the single-point sorption distribution coefficient (K_D) of TYL decreased rapidly as the solution pH increased. A speciation-dependent sorption model that accounted for the contributions of the cationic and neutral forms of TYL fit the data well, suggesting that the sorption may be dominated by both ion exchange and hydrophobic interactions. The isotherm data also fit well to a dual mode model that quantifies the contributions of a site-limiting Langmuir component (ion exchange) and a non-specific linear partitioning component (hydrophobic interactions). X-ray diffraction analyses revealed that the interlayers of montmorillonite were expanded due to the uptake of TYL. TYL molecules likely form a monolayer surface coverage.     

阻尼技术在客车车内噪声控制中的应用

本文以成都客车厂生产的CDK6964型团体客车为对象,通过对车内声、振动特性的测试和分析,针对该车结构声严重,发动机罩壳隔声能力差等缺陷,主要采取了自由阻尼和约束阻尼改进结构,使该车车内平均噪声级在60km/h匀速下由原来的86.4dB(A)降至改进后的73.2dB(A),取得显著成效。     

反硝化除磷的影响特性试验

采用SBR反应器(厌氧/缺氧/好氧工艺),分别研究了乙酸盐及硝酸盐浓度变化对反硝化除磷的影响特性。试验结果表明,当进水COD浓度>230mg/L时,乙酸盐浓度的变化对释磷、除磷速率等影响并不显著。在硝酸盐浓度<30mg/L时,硝酸盐浓度越高,缺氧段除磷速率也就越高。在C/P>23,C/N>5条件下,SBR系统对磷、氮去除率在90%以上。     

基于BN的锅炉超压爆炸事故原因推理与故障诊断

分析了锅炉爆炸的原因,讨论了事故树与贝叶斯网络的特点,编制了以"锅炉超压爆炸事故"为顶事件的事故树,将其转化为锅炉超压爆炸事故贝叶斯网络拓扑结构,利用贝叶斯网络的技术优势,针对锅炉超压爆炸事故贝叶斯网络拓扑结构分别进行了原因推理与诊断推理。实例应用表明,在原因推理中,根节点V_1(压力上升)发生时锅炉超压爆炸事故发生的可能性最高;在诊断推理中,当锅炉超压爆炸事故发生时,根节点V_1(压力上升)一定发生,其次为V_4(定压不准),V_(11)(未装疏水管)发生的可能性最小,为企业进行锅炉超压爆炸事故预测与故障诊断提供了理论依据。     

Sorption of tylosin and sulfamethazine on solid humic acid

Tylosin(TYL) and sulfamethazine(SMT) are ionizable and polar antimicrobial compounds,which have seeped into the environment in substantial amounts via fertilizing land with manure or sewage. Sorption of TYL and SMT onto humic acid(HA) may affect their environmental fate. In this study, the sorption of TYL and SMT on HA at different conditions(pH, ionic strength) was investigated. All sorption isotherms fitted well to the Henry and Freundlich models and they were highly nonlinear with values of n between 0.5 and 0.8, which suggested that the HA had high heterogeneity. The sorption of TYL and SMT on HA decreased with increasing p H(2.0–7.5), implying that the primary sorption mechanism could be due to cation exchange interactions between TYL~+/SMT~+ species and the functional groups of HA.Increasing ionic strength resulted in a considerable reduction in the K_d values of TYL and SMT,hinting that interactions between H bonds and π–π EDA might be an important factor in the sorption of TYL and SMT on HA. Results of Fourier transform infrared(FT-IR) and ~13C-nuclear magnetic resonance(NMR) analysis further demonstrated that carboxyl groups and O-alkyl structures in the HA could interact with TYL and SMT via ionic interactions and H bonds,respectively. Overall, this work gives new insights into the mechanisms of sorption of TYL and SMT on HA and hence aids us in assessing the environmental risk of TYL and SMT under diverse conditions.     

基于DEA-Malmquist指数的山东省生态效率评价研究

以2004牟-2012年面板数据为样本,运用DAE和Malmquist指数模型对山东省17地市生态效率及其变化特征进行测评.结果显示:山东省生态效率呈现波动变化,各地市之间差异明显,有6市达到了效率最优,烟尘、工业固废、工业粉尘和SO2是影响非前沿面城市生态效率提升的重要因素;各地市资源效率与环境效率存在差异,环境效率发展较好的城市数量多于资源效率;技术进步对生态效率的提高起着明显的促进作用;驱动技术创新、优化产业布局,发展循环经济是山东省提升生态效率的有效途径.     

The status and distribution of PCBs along the coast of Vietnam

Environmental Geochemistry and Health - Polychlorinated biphenyls (PCBs), well-known as an important scientific achievement, are now considered as one of the most persistent organic pollutants...     

On-site rainwater harvesting and treatment for drinking water supply: assessment of cost and technical issues

Environmental Science and Pollution Research - This study assessed the performance of rainwater-harvesting systems installed for selected public utilities in the northern provinces of Vietnam where...     

储罐工艺变更管理中的HAZOP应用

采用危险与可操作性(HAZOP)方法分析了石脑油储罐废气排放系统工艺变更的危害因素,特别对废气排放系统的控制参数,给出了逆流、超温、超压、低压/真空等偏差的HAZOP分析结果,并针对高风险的偏差提出了相应的建议措施.