我国城市污泥农用的潜力浅析

由于城市污泥中富含了植物生长所需要的营养物质,城市污泥的农用已经成为了处理污泥的一种重要方法。在废物利用的同时,污泥的农用也有相应的缺点和局限性。文章简述了我国城市污泥的来源和数量以及污泥农用的几种方法,指出了污泥的农用的缺点和局限性,并对我国污泥农用的研究进行了展望,为我国污泥农用的研究和发展提供了部分参考依据。     

混凝工艺预处理中纤板废水的研究

通过筛选,确定了聚合氯化铝(PAC)为混凝剂对中纤板废水进行混凝预处理.由于中纤板废水本身的浓度和脱稳性能随pH变化很大,使得混凝效果最佳的废水pH为5.当PAC投加量为2g/L时,混凝工艺对废水中SS、COD和SCOD的去除率分别接近100％、50％和30％.通过分析PAC的混凝机理,认为PAC的最佳投加量主要与废水中SS有关而与COD关系不大.沉淀时间和助凝剂聚丙烯酰胺(PAM)的投加对混凝效果几乎没有影响,但可以有效加速絮体的沉降和减小污泥体积.研究结果为中纤板废水的混凝预处理提供了详细、可靠的理论依据.     

Heat treatment temperature effect on the microstructure and optical properties of Dy2(WO4)3 powders

Dy₂(WO₄)₃ powders were synthesized through liquid-phase reaction. The structure transformation of Dy₂(WO₄)₃ powders were analyzed by differential scanning calorimetry (DSC), X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). The optical absorption and photoluminescence properties were characterized by UV-vis-infra diffuse reflectance spectra and fluorescence spectra. The Dy₂(WO₄)₃ host could absorb deep UV light and transfer the energy of UV light to Dy³⁺ ions, which convert the high-energy UV light to blue light (482 nm, ⁴ F _9/2→⁶ H _15/2) and yellow light (547 nm, ⁴ F _9/2→⁶ H _13/2). The Dy₂(WO₄)₃ powders could also absorb near UV light and exhibit blue and yellow emissions near 482 and 547 nm, respectively. Heat treating promoted the crystallization and regulated the micro-structure of Dy₂(WO₄)₃ hosts. The bands of W-O_d anti-symmetric stretching vibration exhibited red shift with the increasing of sintering temperature. The W-O_b-W groups tended to combine with each other to form W-O_c-W groups after heat treating. These regulation of micro-structure had influence on the luminescent color of Dy₂(WO₄)₃. The samples could emit yellow-green, white-yellow and white light under the excitation of 350 nm after being treated at 600, 800 and 1 000 °C, respectively. The prepared Dy₂(WO₄)₃ powders have potential to act as UV absorber for solar cell to improve the conversion efficiency and also exhibit potential for white light LED.     

水泥与砂子种类对水泥基材料高温力学性能的影响

研究了600℃下水泥与砂子种类对水泥基材料高温力学性能的影响。结果表明,相比硫铝酸盐水泥和高铝+普硅水泥,普硅水泥具有较好的抗高温性,但矿渣水泥相比其他水泥抗高温性更好。其原因可能是矿渣消解了CH并生成了热稳定性高的Si和Al新化合物。在600℃下,相比河砂、花岗岩机制砂、大理石机制砂、石英石机制砂,石灰石机制砂配制的水泥砂浆抗高温性能最好,原因是在573℃左右硅质骨料中,石英将由α型转为β型,体积膨胀0.85%,导致内部界面出现裂缝,对于钙质骨料则没有明显的变化;温度达到800℃时,石灰石骨料中碳酸盐才发生脱碳作用和骨料将变得疏松,砂浆强度才大幅度下降。     

Hydrothermal synthesis,structure study and luminescent properties of YbPO₄:Tb³⁺ nanoparticles

YbPO4:Tb3+ were synthesized by mild hydrothermal method.The luminescent properties,morphologies and structure of the obtained powders were characterized by photoluminescence(PL) spectra,FESEM,X-ray diffractometer(XRD) and FTIR.The results showed that the prepared YbPO4:Tb3+ nanoparticles were pure tetragonal phase and the average grain size varied with increasing of Tb3+ concentration.Hydrothermal temperature was revealed to be the key factor to enhance the emission intensity of YbPO4:Tb3+ phosphors.The spherical nanoparticles could be effectively excited by near UV(369 nm) light and exhibited green performance at 543 nm(5D4→7F5),489 nm(5D4→7F6) and 586 nm(5D4→7F4).The CIE chromaticity was calculated to be x=0.298,y=0.560.The YbPO4:Tb3+ nanoparticles exhibited potential to act as UV absorber for solar cells to enhance the conversion efficiency.     

中纤板废水处理技术初探

分析了中纤板生产过程中废水的来源、水质、水量及特点，并就目前工艺中存在的主要问题做了初步分析和探讨。在此基础上，提出了处理废水的思路，推荐了更为优化的工艺流程。     

活性污泥-化学混凝与化学混凝工艺比较

在传统混凝烧杯实验的基础上,将实验室培养的活性污泥与化学混凝剂先后加入中纤板废水,并联合曝气和机械搅拌的方式,以期通过活性污泥的吸附絮凝作用,提高混凝效果.将新工艺与传统化学混凝工艺进行比较.结果表明:两种工艺对于悬浮固体(SS)的去除效率均能达到98%以上,但新工艺对于化学需氧量(COD)和溶解性化学需氧量(SCOD)的去除率分别比传统化学混凝工艺高20%和10%;当废水含量突然下降时,新工艺抗负荷冲击能力比传统化学混凝法高,能确保出水水质不大幅下降;新工艺出水Zeta电位的绝对值比传统化学混凝的高,但仍在实现最佳混凝效果的范围内;新工艺对中纤板废水中小粒径颗粒物的去除效果比传统化学混凝工艺好;在新工艺产生的絮体中,污泥将氢氧化铝晶粒和捕获的颗粒物之间的孔隙填充,并将其包裹起来,使得絮体更加致密.     

中纤板废水处理技术初探

分析了中纤板生产过程中废水的来源、水质、水量及特点,并就目前工艺中存在的主要问题做了初步分析和探讨。在此基础上,提出了处理废水的思路,推荐了更为优化的工艺流程。     

Generalized L systems

This paper proposes the concept of generalized L systems, GL systems for short, which can describe asynchronized concurrent phenomena. We have proved that the GL systems are proper extensions of the traditional L systems. We have also defined a classification of GL systems and proved a sufficient and necessary condition for the equivalence of two subclasses of GL systems: two GPDOL (a class of deterministic GL systems) systems L[ m1, m2, ??? mj] and L[ n1, n2, ??? nk] are e-quivalent, iff k = j and there exists a common divisor g of all mi and a common divisor h of all nj such that (?) i: mi/g = nj/h.     

曝气生物滤池在上海周家渡水厂的应用

介绍了上海周家渡水厂采用曝气生物滤池（BAF）预处理黄浦江原水的生产性试验结果，包括BAF的设计参数、运行情况等。试验数据表明，采用BAF预处理工艺对原水浊度、铁、锰、氨氮、亚硝酸盐、CODMn和可同化有机碳（AOC）的去除率分别为40．9％、53．1％、36．6％、39．9％、40．1％、15．4％和54％，提高了出水水质和生物稳定性。