过氧乙酸破解和化学重絮凝改善活性污泥过滤脱水性能

活性污泥中的胞外聚合物(EPS)高度亲水,破坏EPS结构是促使结合水释放的必要过程.为此,研究利用过氧乙酸(PAA)预氧化破解污泥和化学絮凝过程以同步实现污泥减量和脱水性改善,深入解析组合调理过程中污泥絮体形态特征及EPS分布和组成的变化特征.结果表明:PAA处理污泥对其过滤特性影响不大,但有效降低滤后泥饼的含水率;PAA能够有效破解污泥,破坏EPS中蛋白质类有机物,促使结合水释放;随着p H的降低,PAA对污泥脱水性的改善效果更佳,这主要是因为酸性环境有效提高了PAA对污泥EPS的氧化效率;高剂量PAA处理污泥后未见到有完整结构的絮体.投加聚合氯化铝(PAC)和氯化铁后,污泥絮体重新形成,同时污泥更容易过滤且脱水性随之提高.由于具有更强的吸附架桥能力,PAC在改善脱水性方面的效果优于氯化铁.     

计算集群中一种基于任务运行时间的组合预测方案

针对现有单一预测策略不适用于所有异构任务的问题,提出一种基于本地任务与远程任务运行时间的组合预测方案(CPS)和预测精度保证(PAA)的概念。使用GridSim工具集来实现CPS,将PAA作为定量评价由某一特定预测策略提供的预测运行时间精度的标准。仿真实验表明:与本地任务预测策略如Last和滑动窗口中值(SM)相比,CPS的平均相对残差下降了1.58%、1.62%;与远程任务预测策略如平均运行时间(RM)和加权移动平均值(ES)相比,CPS的平均相对残差下降了1.02%、2.9%。因此,PAA能从综合策略所提供的结果中选择接近最优值的预测,CPS增强了计算环境中本地任务和远程任务运行时间的PAA。     

PVA-PAAIPN水凝胶的制备及其溶胀性质研究

利用化学交联和循环冰冻-解冻相结合的顺序逼近法,制备了由和聚乙烯醇（PVA）和聚丙烯酸（PAA）复合的具有互穿聚合物网络（IPN）结构的高分子水凝胶。研究了交联剂含量,PAA含量和温度对水凝胶溶胀性质的影响,实验结果表明,30℃时,交联剂含量为1.0mol%的凝胶溶胀度最大,凝胶中PAA含量越大,凝胶的溶胀度越大;具有IPN结构的凝胶具有温度敏感性质;调节凝胶中PAA和交联剂的含量,可以控制凝胶突变体系的大小。     

基于投影光瞳分布的星地激光通信波前探测

为了解决星地自由空间光学通信系统中的提前角问题,采用了一种基于光强传输的新型波前探测技术——投影光瞳面分布（Projected Pupil Plane Pattern,PPPP）,并通过实验室实验验证了该技术的可行性。PPPP基于TIE光强传输公式,根据不同传输距离下光强分布的变化反解出大气湍流引起的波前畸变。由于PPPP采用的是上行通信激光本身的后向瑞利散射,其测量的大气湍流方向与通信卫星方向一致,因此可以有效解决星地激光通信中的提前角问题。实验模拟了1 m口径的地基望远镜作为上行激光发射装置和后向散射光斑成像设备,通过等效高度分别为10 km和17 km的上行激光后向散射光斑图像来实现对10 km以下大气湍流的波前探测。实验采用的波前畸变模拟装置包括空间光调制器和透明塑料片,实验结果表明,对不同的波前畸变PPPP和通用的夏克-哈特曼波前探测器可以实现相似的波前重构,两者重构相位的残差约为初始相位的30%。     

PAA与Fenton试剂对污泥的减容效果

解决污泥问题的最好办法就是污泥减量.研究了两种强氧化剂过氧乙酸(PAA)和Fenton试剂对污泥的溶解特性.研究表明PAA与Fenton试剂对污泥都有一定的减容效果,相比而言,Fenton试剂对污泥的减容效果更为显著.PAA溶解污泥的极值时间为2 h,Fenton试剂溶解污泥的极值时间为0.5 h.在加入1 mol/L的NaOH,至污泥液pH=10的前提下,PAA和Fenton试剂对SS(suspend solid)的减少率分别高达65.4%,87.8%.     

Measurement of surface crystallinity of PAA and PAANa coatings and its effect on hydrophilicity of coatings

1　INTRODUCTIONAsanimportantwater solublemacromoleculecompound,poly (acrylicacid) (PAA)anditssaltshavebeenwidelyused[1] .Utilizingitsfinefilm form ingcapacityandhydrophilicity ,Okoroaforetal[2 ] ,andPanetal[3] developedanewhydrophilicpaintforaluminiumfin[2 ,3] .Hydrophilic paintforheat ex changerofairconditioningdemandslittlesurfacecon tactangle ,sothatcontinuoushomogeneouswaterfilmcanformeasily ,andcandrainoffcondensedwa teronthesurfaceoffintimely[4 6 ] .Hydrophilicityofcoatingsisaffec…     

Regularity control of porous anodic alumina and photodegradation activity of highly ordered titania nanostructures

A two-step anodizing process was used to prepare wide-range highly ordered porous anodic alumina membrane （PAA） in the electrolyte of oxalic acid. The effects of anodic voltage, anodizing time, size of aluminium foil and additives on the regularity of PAA membrane were also studied in the process of two-step anodization. The template method was combined with the sol-electrophoresis deposition and sol-gel method respectively to prepare highly ordered titania nanostructures. The diameter and length of the obtained nanostructures were determined by the pore size and depth of the PAA template. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were, used to characterize the morphology and phase structure of the PAA template and the titania nanostructures. The results show that the anodizing time and the additive of ethanol have a great effect on the regularity of PAA template. This can be explained from the self-organized process and the current density theory. A theoretical model based on the self-organized process was established to discuss the formation mechanism of PAA template from the chemical perspective. The titania nanostructures prepared with this method has a high specific surface area. Furthermore, the photocatalytic activity of titania nanostructures on methyl orange were studied. Compared with ordinary titania membranes, the titania nanostructures synthesized with this method have higher photodegradation activity.