好氧颗粒污泥等温吸附甾体雌激素

为了研究好氧颗粒污泥对甾体雌激素E1、E2、EE2的吸附作用,通过摇瓶试验考察了吸附平衡时间及在不同温度下的等温吸附过程,对该过程进行了Freundlich方程和Langmuir方程拟合分析,并采用SEM观察好氧颗粒污泥结构.实验结果表明,吸附40min后基本达到平衡;吸附量随着温度的升高而减少,在20℃时,E1、E2、EE2最大吸附量分别为60.98、58.82、82.64μg/g;吸附过程符合Freundlich方程和Langmuir方程,其相关系数R2分别为0.93~0.99和0.92~0.99;吸附后好氧颗粒污泥表面及内部均发生了变化.     

板材成形无网格法模拟中的接触搜索处理

为提高板材冲压成形无网格法数值计算的效率,实现接触搜索并加快搜索速度,提出采用矩阵法处理接触搜索,并构造稀疏"矩阵"记录各节点信息,接触搜索时利用该信息可快速找到从节点影响域内的节点,并利用这些节点构造规模减小的矩阵,可加快矩阵行列式的计算,达到快速且精确地处理接触搜索的目的.数值算例表明,采用矩阵法处理接触搜索是合适的.     

功能梯度材料的点插值无网格法

建立了一种新的求解功能梯度材料问题的点插值无网格法,这种无网格方法将径向基函数和多项式基函数耦合构造具有插值特性的近似函数,并将其应用于弹性力学问题Galerkin形式的无网格方法。在计算过程中,取高斯点的材料参数模拟功能梯度材料特性的变化,由于形函数及其导数的构造相对简单,并且满足Delta函数性质,所以该方法具有计算量小、精度高、可以像有限元法一样直接施加边界条件的优点。最后通过数值算例证明了该方法的有效性。     

Development of a novel modified EGSB reactor for municipal sewage treatment at ambient temperatures

A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a conventional EGSB(EGSBc) reactor.Performances of these two reactors were compared in treating municipal sewage at ambient temperatures ranging from 8 to 26 ℃.At an upflow liquid velocity(Vup) of 10.3 m/h,the mean concentrations of filtrated COD(CODfilt) and COD of the EGSBm effluent were determined to be 59.4 and 95.9 mg/L,respectively,which were significantly lower than those of the EGSBc effluent operated under identical experimental conditions.When the organic loading rate was suddenly increased from 1.2 to 7.2 kg COD/(m3·d),the EGSBm regained the removal efficiency of previous operation phase in 10 d.Hydrodynamic characteristics of the reactors were compared using the residence time distribution(RTD) model.It was found that the treatment efficiency of EGSBm kept increasing as the Vup increased.The polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE) technique was used to analyze the microbial diversity in EGSBm.Fingerprinting pattern indicated that some species in the inoculating sludge were still reserved in the granular sludge of EGSBm,moreover,several new species occurred.     

Shut-cut nitrification characteristics of aerobic granule in a sequencing batch airlift reactor at low temperature

To investigate the shut-cut nitrification characteristics of aerobic granule,an aerobic granular sequencing batch airlift reactor(AG-SBAR) was carried out with mixed carbon sources of sodium acetate and glucose at 10±1 ℃.Results indicated that ammonia oxidizing bacteria was accumulated inside the aerobic granules and the reactor performed stably with shut-cut nitrification for a long term at low temperature.During the stable operation period,the effluent ammonia nitrogen concentration was maintained at 13.6 mg/L without nitrate and nitrite when the COD/N ratio was 20:1.However,the effluent concentration of ammonia nitrogen was below 0.5 mg/L with effluent nitrosation ratio of 96.7% on average when the COD/N ratio was reduced to 15:1 and 10:1.And the effluent phosphorus concentration was less than 0.4 mg/L during the stable period with the sludge retention time of 30 d.The phosphorus removal efficiency was not strongly influenced by the adjustment of COD/N ratio in this experiment.The removal efficiencies for COD,NH4+-N and PO43--P were 91.3%-94.6%,97.9%-99.7% and 97.1%-99.5%,respectively.     

离心渗透等离子刻蚀法制备无基底阵列式碳纳米管复合膜

介绍了一种将聚乙烯醇渗透于碳纳米管中的方法,然后采用等离子刻蚀碳纳米管薄膜制备出了无基底阵列式碳纳米管复合膜。实验发现,聚乙烯醇可以起到固定碳纳米管的作用,而且找到最佳聚乙烯醇溶液粘度,并且研究了刻蚀时间对刻蚀效果的影响。此外还研究了膜表面处理对聚乙烯醇渗入碳纳米管膜性能的影响,结果表明,膜表面处理能有效改善聚乙烯醇对碳纳米管膜的渗入性。     

一种好氧颗粒污泥的内部构造分析

采用城市污水处理厂的活性污泥为接种污泥,以人工配制污水为原水,在序批式反应器(SBR)中培养出好氧颗粒污泥,对其冷冻切片后进行显微观测.同时,根据颗粒污泥内部基质(COD,N,DO)在各个阶段的变化,分析颗粒污泥内部构造的形成过程.研究发现,好氧颗粒污泥的内部构造可以描述为:第一层,即好氧颗粒污泥表面层,主要由异养型生物组成,厚度约为220～340 μm;中间层,主要由自养型生物组成,厚度约为380～550 μm;第三层位于颗粒污泥中心,微生物量较少,主要由无机成分组成,存在明显的空腔,其厚度由好氧颗粒污泥粒径决定.     

双体对转驱动电机的转矩平衡仿真研究

水下双体对转驱动电机分为前后两台同轴无刷直流电机,分别驱动两个对转螺旋桨.这一特殊结构使得正反转电机的驱动问题尤其是输出转矩平衡问题显得尤为突出.依据单体无刷直流电机的数学模型,运用工程设计方法进行电流调节器和转速调节器的设计和软件仿真分析,得出理论上的最佳双闭环控制参数,并在单电机的分析基础上,建立双电机的控制数学模型来研究输出转矩平衡问题,通过模拟仿真,得出理论上可以到达双电机输出转矩平衡的控制算法,为后续的实验研究提供了理论依据.     

2008年第3季度上海市无糖食品质量专项监督抽查结果

无糖食品是指不含蔗糖（甘蔗糖和甜菜糖）和淀粉糖（葡萄糖、麦芽糖、果糖）,用麦芽糖醇、山梨醇、木糖醇等来替代食糖的食品。目前市场上的无糖食品种类很多,包括了无糖的糖果、巧克力、麦片、奶粉、藕粉、豆奶（粉）、饼干、糕点、面条、烧烤食品、饮料、冷饮、罐头食品等等。     

对称叠层板稳定计算的一种新方法

无单元法是一种新的数值算法,它信息处理简单,其基本思想是在计算域上用一些离散的点由最小二乘法来拟合场函数,从而摆脱了单元的限制,因为它应用了滑动最小二乘法,所以与有限元不同,它的近似场函数不一定精确通过计算点。这会使计算略为复杂,但与这种方法带来的方便性相比,这点缺陷是微不足道的,因此这种方法愈来愈引起人们的关注．笔者将无单元法用于对称叠层板的屈曲问题,通过计算不同边界条件下各向同性板和对称叠层板的屈曲荷载参数,验证了该法的有效性,且精度较高,有着广泛的工程应用前景．