A review on the dewaterability of bio-sludge and ultrasound pretreatment

Bio-sludge, which contains large quantities of water, biomass and extracellular polymeric substances (EPS), is difficult to be dewatered as a "super-compactable" sludge [Water Res. 35 (5) (2001) 1358]. Reported water content in bio-sludge was commonly about 80-90% wt after dewatering process. The EPS and the form of water in sludge influences the structure of sludge. Adding cationic fluctuations can change the form of water in sludge and increase the velocity of dewatering process, but has little influence on the final water content. According to Bien's work [Water Sci. Technol. 36 (4) (1997) 287], a combination of ultrasound or other method could agglomerate the sludge, improve the activities of biomass [Ultrasonics 38 (2000) 711; Ultrasonics 40 (2002) 25], enhance anaerobic process [Water Sci. Technol. 36 (11) (1997) 155; Water Sci. Technol. 36 (11) (1997) 121; Water Res. 35 (8) (2001) 2003; Water Sci. Technol. 36 (12) (1997) 117] and decrease over 10% final water content of sludge. The mechanisms of ultrasonic influence on sludge are not very clear, but the application of ultrasound to industrial process is relatively easy and possible.     

新型稀土镁合金螺钉体内促骨修复及体外生物相容性研究

为测试新型稀土镁合金的生物相容性及降解产物致敏性; 评价新型稀土镁合金螺钉对骨伤模型的治疗效果, 基于NZ30K镁合金添加Mn元素制成新型稀土镁合金, 并通过后期加工制成不同规格的螺钉. 将稀土镁合金螺钉浸入磷酸盐缓冲液中制作浸提液, 于大鼠后肢背部皮下注射, 观察浸提液皮下致敏性. 将螺钉打磨制成圆片植入到大鼠皮下, 观察皮下降解产气情况, 以可吸收骨蜡作为对照同位置皮下植入. 建立兔骨损伤模型, 将稀土镁合金植入, 定期拍摄X光检查螺钉降解情况, 按照时间顺序分别于8周、12周、16周处死实验兔制作肝肾切片、骨切片, 评价肝肾毒性及体内降解情况; 同期以ZA75镁合金为基础添加0.3% Mn元素制成新镁合金, 作为对照组对比稀土镁合金对大鼠骨髓间充质干细胞成骨分化效果. 将浸提液过滤稀释后添加至细胞培养板中, 加入成骨诱导液培养, Westernblot蛋白电泳实验测定骨保护蛋白(OPG)表达情况. 新型稀土镁合金浸提液未表现出致敏性, 皮下降解结果显示植入初中期有气腔产生, 中后期气腔消失, 镁合金完全降解; 组织切片显示, 兔股骨螺钉植入在前中期有一定肝肾毒性, 植入中期促骨生长效果相较于前期更为明显, 植入后期未见明显肝肾毒性, 螺钉降解完全, 植入部位骨质增强; 兔股骨植入降解结果显示植入前期未观察到明显的促进骨生长效果, 螺钉与骨质嵌合紧密, 植入中期促骨生长修复效果呈现, 局部骨组织出现膨隆包裹住螺钉降解产物, 植入后期螺钉完全降解, 植入位置有一小孔未闭合, 股骨近端明显膨隆; 蛋白电泳实验显示, 新型稀土镁合金浸提液可增加OPG表达, 具有良好的生物相容性. 基于NZ30K开发的新型稀土镁合金在动物实验及细胞实验阶段表现出良好的生物相容性, 可为临床应用提供一定参考.     

Structural change from homogenous structure to staging in benzoic acid intercalated LDH: experimental and molecular dynamics simulation insights

The intercalation the of 4,4'-oxybis(benzoic acid) anion (OBA(2-)) into MgAl-layered double hydroxide (LDH) was carried out in formamide, and the structural change of the nanocomposites from homogenous to staging was investigated through in situ XRD, FT-IR, TG-DSC, SEM and molecular dynamics (MD) simulations. In both formamide and water, the nanocomposites had a homogenous structure with a basal spacing of ～1.7 nm, showing the configuration of OBA(2-) was vertical to the LDH layers; however, with a decrease in water content after drying, the structure changed to a staging with a basal spacing of 2.62 nm. This resulted from the 1.72 nm phase and another one of 0.85 nm, which was produced by the configuration of OBA(2-) horizontal to the LDH layers. MD simulations revealed that the LDH layers distorted surrounding OBA(2-), and the deformation became more severe with decreasing water content in the interlayer, leading to the staging formation. The simulated XRD pattern confirmed that the staging observed in the experimental pattern was of the Daumas-Hérold type.     

Coherence properties of the scattered electromagnetic field generated by anisotropic quasi-homogeneous media

The coherence properties of the scattered field generated by linearly polarized and uniformly unpolarized electromagnetic plane waves incident on anisotropic quasi-homogeneous media are studied. The analytical expressions for the spectral density and the spectral degree of coherence of the three dimensional scattered field are derived. The results of the numerical simulations indicate that not only the properties of the anisotropic media have a great effect on the coherence properties of the scattered field, but also the polarization of the incident wave. And most important, the effect of the polarization of the incident wave on the coherence properties of the scattered field nearly concerns the properties of the anisotropic media. There are also close and interesting relations between the coherence properties of the scattered field that generated by the anisotropic media and by the corresponding isotropic media.     

Propagation of confluent hypergeometric beam through uniaxial crystals orthogonal to the optical axis

Based on the theory of paraxial electromagnetic beams in anisotropic medium, propagation properties of a linearly polarized confluent hypergeometric (HyG) beam through uniaxial crystals orthogonal to the optical axis are investigated. Analytical expressions are derived for the resultant optical field components. Effects of separate beam parameters together with the ratio of refractive indices of crystals on transversal intensity distributions are revealed by numerical calculations, respectively. It is shown that the beam profile finally converts into an elliptical shape due to influences of anisotropic crystals. Moreover, it is also indicated that through suitable selection of parameters, types of the optical vortices of resultant field would change from a central dark spot to a slight dark ring or an axial shadow during the propagation. These numerical results may provide alternative advantages to the trapping of tiny particles by utilizing HyG beams in practical experiments.     

基于二氧化锰和金属有机框架化合物协同作用构建的立体复合阵列超级电容器电极

以硝酸锌、硝酸锰和2-甲基咪唑为原料,采用多步计时电位法和静置法,制备了氧化锌-二氧化锰-金属框架有机化合物（ZnO-MnO2-MOF）复合材料阵列电极。 通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X光电子能谱(XPS)和X射线衍射(XRD)等技术手段对比分析了该复合材料的结构和形貌,并采用循环伏安法、恒电流充放电、电化学阻抗和循环充放电法研究了电极的电化学性能。 结果表明,与氧化锌-二氧化锰（ZnO-MnO2）复合材料阵列电极（Csp=121 F/g,j=2.5 A/g）相比,由于二氧化锰和金属有机框架化合物（MOF）的协同作用,修饰MOF后的ZnO-MnO2-MOF复合材料阵列电极具有较小的内阻,电容器比电容（Csp=146 F/g,j=2.5 A/g）性能提升了20%,具有更好的可逆法拉第反应和稳定性。     

(*)-Serial coalgebras

In this paper, we introduce the notion of (*)-serial coalgebras which is a generalization of serial coalgebras. We investigate the properties of (*)-serial coalgebras and their comodules, and obtain sufficient and necessary conditions for a basic coalgebra to be (*)-serial.     

新一代运载火箭一体化供电测控系统设计

新一代运载火箭测量系统承担获取射前和飞行过程中遥外测数据和实施火箭飞行安控的重要任务,在执行发射任务时,测量系统不仅要对火箭关键参数进行长时间的不间断监测,还要对测量系统地面测控设备进行状态监测,实现加注阶段前端“无人值守”。对地面测控系统人员保障及人员对设备的操控提出了很高要求。为此,本文提出了一体化供电测控系统,介绍了系统组成及技术革新,一体化测控系统经过了新一代运载火箭首飞考核,得到了充分的试验验证。     

一款小角X射线散射原位测量专用简易样品加热装置

原位加热实验是同步辐射小角X射线散射领域的新热点。本文针对同步辐射小角X射线散射中需要加热并原位实时检测的实验而设计的一款样品简易原位加热专用装置,该装置主要由温控器、样品池、固定架组成,它具有结构简单、操作容易的特点。本文介绍该装置的基本结构、特点并采用该装置进行原位加热干燥褐煤实验,通过分析实验结果验证装置的可行性。     

石墨烯衍生物的合成及应用

石墨烯是继富勒烯、碳纳米管之后碳纳米材料研究领域涌现出来的又一颗崭亮新星。表面功能化处理是石墨烯强化其优异的本征性能和赋予其他新颖功能的主要技术途径。近年来,研究者相继开发了一系列石墨烯改性与功能化的技术方法,制备得到了多种结构特异、组成丰富和性能独特的石墨烯衍生物。本文基于该领域研究的最新进展,从石墨烯化学的角度出发,综述了石墨烯主要衍生物的制备方法以及应用途径,其中主要包括石墨烯的加氢与氟化、有机功能化、聚合物对石墨烯的共价与非共价修饰、石墨烯衍生物在生物医药研究领域的应用等,并对目前相关研究领域的发展趋势进行了总结和展望。