反应温度对渣油加氢反应过程的影响

以塔河常压渣油和沙轻减压渣油为原料,在高压釜反应器中研究了其它反应条件相同时,反应温度对渣油加氢反应过程的影响。结果表明,在实验所研究的反应温度内,两种渣油的转化率、汽柴油收率、硫和氮的脱除率都随反应温度的升高而增加,且在380～400℃均会出现一个拐点,证明高温有利于渣油的加氢转化和硫、氮的脱除,但由于焦炭产率随反应温度的升高而显著增加,引起催化剂失活速度加快,故渣油加氢反应温度不宜过高。硫含量较高的沙轻减渣的转化率、汽柴油收率、硫和氮脱除率均高于塔河常渣,说明大分子含硫化合物易于分解生成小分子物质,小分子再进入催化剂微孔中进一步发生加氢反应。

脉冲熔融热导法测定铀铌合金氮含量的研究

采用脉冲熔融热导法并结合LECO TC—436氧氮分析仪测定铀铌合金中的氮,讨论了分析功率、助熔剂种类及称样量对测定结果的影响,确定了最佳分析条件。结果表明,本实验测定铀铌合金氮含量的相对标准偏差小于15%,氮的加标回收率为84%～93%,方法的检出下限为20μg/g,与经典凯氏蒸馏法测定的结果基本一致。

阻燃剂三嗪三苯基次膦酸甲酯的合成及应用研究

以三聚氯氰和苯基次膦酸二甲酯为原料,合成氮、磷元素协同阻燃化合物2,4,6-三（O-甲基-苯基次膦酰基）-1,3,5-三嗪。探讨反应时间、反应温度、苯基次膦酸二甲酯滴加速度、原料配比对产率的影响,最佳工艺条件为苯基次膦酸二甲酯和三聚氯氰物质的量比为3.2,15~40℃分三批滴入苯基次膦酸二甲酯,80℃持续反应4h,产率为95.4%。通过FT IR,1 H NMR,差热分析及极限氧指数等技术表征产物的结构及性能。实验结果表明,该阻燃化合物分解温度为236℃,与材料相容性好,阻燃效果佳,且合成工艺简单,有很好的开发应用前景。

Nitrogen and Phosphorus Removal from Agricultural Wastewater Using Constructed Rhizofiltration in Durban, South Africa

Constructed rhizofiltration is a relatively new technology and has potential in agricultural wastewater treatment. It has been reported to reduce heavy metals in wastewater but no substantive work has been reported about its ability to remove nitrogen and phosphorus, particularly in agricultural wastewater. If this technology＇s worth in nutrient removal from wastewater can be proved, it can save time as well as reducing wastewater treatment cost. Influent and effluent nitrogen and phosphate concentrations in the constructed rhizofiltration were measured and it was found that there was a significant difference between the two water samples （P = 0.01）. It was also found that more nitrogen and phosphate were retained by planted region （P = 0.01） compared to unplanted （P = 0.02）, demonstrating high removal efficiency in the planted region than in the unplanted region. Eighty six percent （86%） removal efficiency of phosphorus was achieved at some points in the planted region while 71% was achieved for nitrogen. These results indicate that constructed rhizofiltration systems, if properly constructed and planted with macrophytes and maintained, can be used for nitrogen and phosphorus removal in wastewater and thus could be used as an alternative technology for agricultural wastewater treatment.

中华盒形藻三类大小细胞的生化组成

用ｆ／２培养液培养的中华盒形藻的三类不同大小细胞进行生化组成分析，结果表明，蛋白质、氨基酸、核酸、糖类和叶绿素等在细胞中的含量随细胞的缩小而减少，其中，糖类减少的比例最小，在小型细胞中糖类相应于蛋白质增加１３．５％，三类细胞中的Ｃ／Ｎ比值分别为３．８，４．３和４．７，反映该藻细胞在缩小期间碳水化合物比含氮化合物有更多的积累．这显示，硅藻细胞从营养生长期过渡到生殖生长期过程，除了细胞大小参数外，细胞中的Ｃ／Ｎ比值的增加可能是重要的内部因素之一．

Development of optical nanoprobes for molecular imaging of reactive oxygen and nitrogen species

Reactive oxygen and nitrogen species （RONS） play important roles in cell signal transduction. However, overproduction of RONS is associated with a series of pathological processes and may disrupt cellular homeostasis, causing oxidative and nitrosative stress. Accurate methods to selectively and specifically monitor RONS in living systems are required to further elucidate the biological functions of these species. Optical imaging possesses high sensitivity, high spatiotemporal resolution, and real-time imaging capability. These qualities are advantageous for the detection of RONS in living systems. This review summarizes the development of optical nanoprobes with near-infrared （NIR） fluorescent, upconversion luminescent, chemiluminescent, or photoacoustic signals for molecular imaging of RONS in living systems. In this review, we discuss the design principles and advantages of RONS-responsive activatable nanoprobes, as well as applications of these optical imaging modalities in different disease models.

我即我食 vs．我非我食——稳定同位素示踪人体代谢异常初探

稳定同位素分析揭示古代（现代）人群的食物结构，其原理为＂我即我食＂，即人体组织的稳定同位素比值，与其消化吸收转化而来的食物组分，存在着一一对应关系。然而，当人体代谢发生异常时，这种对应关系将被打破，产生＂我非我食＂现象。目前，探究＂我非我食＂与古代（现代）人体的健康之联系，已成为生物医学和生物考古界的研究热点。颇为遗憾的是，迄今为止，我国尚无学者对此有所关注。为此，本文以中国北方地区2名代谢性异常患者（直肠癌为例）头发样本为研究对象，通过对人发系列的C、N稳定同位素分析，追踪癌症患者头发同位素值的变化趋势，探讨其生理病理因素与稳定同位素之间的内在关系。研究结果显示：人发C、N同位素比值的变化，与其健康状况密切相关。在直肠癌发病初期，患者的δ13C与δ15N值均呈现出上升趋势，这可能是癌细胞代谢活跃、更多地利用机体中的14N和12C所致，或者与癌细胞具有未知的、独特的代谢途径相关。最后，详细阐述了＂我即我食＂和＂我非我食＂的区别和联系，并对如何在我国开展此领域的研究进行了展望。

A^2/O与MBR工艺在同规模城镇污水厂中的设计与应用

近年来MBR工艺在污水处理厂的应用越来越广泛,与常规A^2/O工艺相比,该工艺具有占地面积小、出水水质好、工程直接投资较高等特点。某城市近年来建设的两座20×10~4m^3/d规模的污水处理厂分别采用常规A^2/O工艺和MBR工艺,目前都已投入运行。介绍了这两座污水处理厂的工艺流程、设计参数、实际进出水水质,并对两工艺的运行效果及运行经济指标等进行了比较分析。研究结果表明,MBR工艺占地小,布置紧凑、处理效果优,适合对尾水有回用要求的中小规模污水厂;A^2/O工艺运行稳定,处理成本低,适于各种规模的污水厂,若出水回用需增加或调整深度处理工艺。其结论可为同类工程设计的工艺选择和运行提供参考。