Aqueous photolysis of tetracycline and toxicity of photolytic products to luminescent bacteria

The extensive utilization of antibiotics in the pharmaceutical therapies and agricultural husbandry has led to the worldwide pollution in environments. In this study the photolysis behaviors of tetracycline (TC) and toxicity of its degradation products were investigated. The results showed that TC photolysis followed first-order kinetics. The photolysis rate was found to be dependent on the initial TC concentration and increasing TC concentration from 10 to 40mgl(-1) led to the decrease of the photolysis rate constant from 0.0045min(-1) to 0.0014min(-1). TC photolysis was highly pH-dependent and strongly enhanced at high pH value. Markedly elevated TC photolysis was also observed in the presence of nitrate and dissolved organic matter. Upon irradiation for 300min, only 15% reduction of total organic carbon (TOC) occurred in spite of quick conversion of 73% of TC, suggesting that a majority of TC transformed into intermediate products without complete mineralization. The intermediate products from TC photolysis were analyzed using high-performance liquid chromatography-electrospray ionisation-mass spectrometry (HPLC-ESI-MS) and the main photolysis products of TC were proposed. The toxicity of the photolysis compounds was evaluated using luminescent bacterium, and the results revealed that the toxicity increased with irradiation, indicative of a higher adversity risk of the degradation products of TC on bacteria upon photolysis.     

铝合金空间结构抗火性能研究进展

铝合金材料在高温下的力学性能较差,考虑到铝合金结构常用于重要大型空间结构,其抗火性能与人员生命财产安全密切相关,对国内外近年来关于铝合金空间结构抗火性能的研究进行了系统综述与分析。首先,总结了有关铝合金结构高温性能的研究,包括材料的高温性能、构件和节点的高温性能和空间结构的整体抗火性能等。随后,指出了大空间火灾与一般室内火灾的不同,并对比了各种大空间火灾温度场确定方法的优缺点;总结了有关钢结构构件在火灾下温升的确定方法,并强调了火焰辐射在大空间火灾下的重要影响;阐述了有关大空间结构整体抗火性能的研究;介绍了性能化抗火设计思想及其优越性。最后,总结了有待解决的关键问题和需进一步开展的工作。     

改进的物元可拓模型在台风灾害预评估中的应用

以数值天气预报产品为信息源,选择降水量、降水强度、最大风速、经济易损性作为评价因子,建立了可拓模型,并进行了台风灾前的灾害预测性评估。针对物元可拓法在台风灾害预评估应用中的不足之处(当待评估的数据超出某一指标评价指标范围,其关联度函数就会出现无法计算的情况),对原有模型中经典域的量值作规格化处理和改变关联度计算,以海南岛的台风历史灾害数据为基础,建立了新的评估模型,并将GIS与评估模型结合开展实例应用,结果表明:该方法是可行性。     

Numerical simulation of DPF thermal regeneration process based on an improved dynamic model

ABSTRACT

In this paper, an improved kinetics model of soot oxidation based on the traditional B-K model is employed to characterize the thermal regeneration process of diesel particulate filters (DPF). Considering the influence of specific surface area and inhibition factor on soot oxidation, the regeneration process is simulated and analyzed using the commercial FLUENT software combined with UDF method. The results show that soot particles react from the middle of the filter to both ends, and the temporal profile of soot mass in the thermal regeneration process could be divided into three sections: smooth reaction, rapid reaction, and late reaction. The regeneration time decreases with the increasing of the incoming oxygen volume fraction. When the thickness of the deposited soot layer is less than 0.1 mm, the regeneration time is prolonged as the thickness of the deposited layer decreases. When the thickness is more than 0.1 mm, the regeneration time shows the opposite trend with the thickness of the deposited layer. Meanwhile, the curve of maximum wall temperature changing with time is divided into heating, rapid-burning, and slow-burning regimes. The maximum wall temperature increases as the volume fraction of oxygen flow increases, and as the deposited layer thickness increases.     

苏门答腊海域海啸地震及地壳深部结构

近10年来苏门答腊俯冲带大震频发,并引发灾难性海啸,使之成为全球关注的焦点。特别是2004年和2012年的两次大震所带来的科学问题在许多方面超出现有认识。国际上对苏门答腊地区已开展了大量的地质学、地球物理学等多方面的调查研究,应用了许多新方法并取得了许多新认识。解读苏门答腊的构造背景和地质演化史对于认识俯冲型大地震的产生机理是必要的,对此类地震的发生过程和规律的研究,对于理解海啸产生的条件和防灾减灾有十分重要的现实意义。本文对苏门答腊地区的地震活动和深部构造进行了详细分析,对近年关于该地区的世界性研究成果进行了总结,梳理出若干亟待研究的科学问题,进而提出开展苏门答腊俯冲带地震3D层析成像的具体实施路线。     

不同碳源条件下草菇内切型纤维素酶基因(egl)转录表达的分析

利用Northern blot方法分析了不同碳源条件下草菇內切型纤维素酶基因(eg1)的表达.结果发现,在含有纤维素的液体培养基中生长10 d,eg1在草菇菌丝中有高效表达;纤维二糖、α-乳糖、β-乳糖,也能诱导eg1的表达,但和纤维素相比,eg1的表达量相对较低,并且它们的诱导效应在加入这类糖12 h后迅速减弱;槐糖和龙胆二糖的诱导作用非常弱.在天然稻草为基质的固体栽培料生长时,草菇eg1的表达和草菇菌丝生长与出菇相对应,在菌丝生长期(d 8)可见eg1的表达,d 12时菌丝已长满,表达减弱,在出菇及菇体的分化及增大期,eg1的表达量逐渐增强,在成熟期达到最高水平;表明在草菇菇体发育中需要更多碳源及能源的补充,eg1在这方面起着非常重要的作用. 图4 参14     

我国水资源开发利用中亟待解决的几个认识问题

本文在分析８０年代在以来我国用水变化趋势基础上，探讨了北方地区的缺水程度，并对南水北调工程和可调水量提出了下些看法；文章还从水资源管理模式、法制和法规建设等方面阐述了对当前我国水资源管理政策方面的认识，从水的有效利用与水源保护、水的定价与成本回收、与水有关的社会与环境问题等方面论述了我国２１世纪将面临的有关水问题。     

Towards Sustainable Urban Environmental Management in Jiangyin city, East China

Dramatic economic and social changes have taken place in Jiangyin city due to rapid and uneven urbanization and industrialization. The environmental degradation has followed driven by these changes since the 1980's. With the pressures and effects of environmental deterioration, the city has implemented environmental management to hold back the trends of negative environmental changes. From the viewpoint of systems, DPSER is a good model for urban environmental changes to understand the causes, pressure, state, effect, existing responses and future action strategies. We took Jiangyin city, a developed city in South Jiangsu province, East China, as an example, and analyzed the characteristics of environmental changes and urban responses using DPSER model. Some operational strategies have been put forward to direct the city environmental management towards a sustainable road step by step.     

危险废物焚烧飞灰玻璃化产物危险特性

《国家危险废物名录》中HW18焚烧处置残渣明确规定,"危险废物等离子体、高温熔融等处置过程产生的非玻璃态物质和飞灰"判定为危险废物.为降低危险废物焚烧飞灰的生态环境危害,并期望对其进行更好的资源化利用,采用国际前沿的玻璃化技术对危险废物焚烧飞灰进行处置,制备得到玻璃态物质,即玻璃体.结果表明:①焚烧飞灰掺杂不同比例的高岭土、SiO₂、CaO后,可形成符合玻璃体烧制条件的CaO-Al₂O₃-SiO₂系统,经过2 h 1 400℃高温熔融,几种不同配料比的玻璃体均可形成无定型的、微观表面平滑的结构.②玻璃体对Zn、Cr、Pb、Cd和As等重金属均有不同程度的固化作用,采用HJ/T 300-2007《固体废物浸出毒性浸出方法醋酸缓冲溶液法》测得的重金属浸出浓度均低于焚烧飞灰.③采用Hakanson公式中潜在生态危害模型对焚烧飞灰及玻璃体进行风险评价显示,几种玻璃体的RI（潜在生态危害风险指数）均在50~100范围内,呈中等风险,低于焚烧飞灰（299.34）.④效果最优的玻璃体的碱度（CaO/SiO₂,质量分数）为0.3,呈现浅绿色且质地透明的外观形貌,它对Zn、Cr的浸出浓度分别为0.12、0.05 mg/L,但均未检出Pb、Cd、As,远低于焚烧飞灰浸出浓度及GB 16889-2008《生活垃圾填埋场控制标准》中生活垃圾焚烧飞灰和医疗废物焚烧残渣浸出限值（Zn、Cr、Pb、Cd、As浸出浓度限值依次为100、4.5、0.25、0.15、0.3 mg/L）,该玻璃体的RI为60.05,远低于焚烧飞灰的299.34.研究显示,采用玻璃化技术对焚烧飞灰进行处置后,焚烧飞灰可形成无定型的玻璃态结构,碱度为0.3时,玻璃体的重金属浸出浓度最低,且潜在生态风险最低,为最适用于焚烧飞灰玻璃化技术的调控比例.      

用酚渣油制备酚渣油树脂

用酚渣油为原料，模拟酚醛树脂合成方法，对酚渣油的催化交联、松香改性等化学过程进行了研究，合成出性能良好、可用于制备涂料与胶粘剂的酚渣油树脂。试验结果表明，依照该工艺生产的酚渣油树脂，其主要技术指标达到制备涂料用酚醛树脂的标准，用酚渣油制备的涂料和胶粘剂的性能优于酚醛树脂。