一种新型环保铝合金无铬钝化处理液

用氟钛酸、氟锆酸盐、改性有机硅树脂等为主要成份,配成一种新型铝材无铬钝化处理液,代替传统六价铬产品,所处理的铝合金产品品质,达到传统含铬钝化处理后的品质,实验达到无污染、节水节电的环保要求。     

Acceleration of the redox kinetics of VO2+/VO2 + and V3+/V2+ couples on carbon paper

The redox kinetics of VO²⁺/VO₂ ⁺ and V³⁺/V²⁺ couples on a carbon paper (CP, HCP030 N, Shanghai Hesen, Ltd., China) electrode were investigated in terms of their standard rate constant (k ₀) and reaction mechanism. The values determined for k ₀ for VO²⁺ ?? VO₂ ⁺ and V³⁺ ?? V²⁺ using the CP electrode are 1.0 × 10^?3 and 1.1 × 10^?3 cm s^?1, respectively. The value of k ₀ increases by one or two order(s) of magnitude compared with values obtained using electrodes composed of pyrolytic graphite and glassy carbon. The acceleration of the redox kinetics of vanadium ions is a result of the large surface area of the CP electrode. An inner-sphere mechanism for the reaction on the surface of the electrode is proposed. The kinetic features of vanadium redox reactions on the CP electrode reveal that CP is suitable for use as the electrodes in vanadium redox-flow batteries.     

PBA/OMMT制备及其对PA6力学性能的影响

用十二烷基磺酸钠(SDS)将Na基蒙脱土(MMT)改性成有机蒙脱土(OMMT),采用原位聚合法制备了聚丙烯酸丁酯(PBA)/OMMT,并将其按适当比例添加到尼龙6(PA6)中。通过红外光谱仪、差示扫描量热仪等表征了OMMT、PBA/OMMT的结构,并检测了PA6/PBA/OMMT复合材料的力学性能。结果表明:添加5%的PBA/OMMT后,PA6/PBA/OMMT复合材料的拉伸强度提高了23.1%,缺口冲击强度的降低幅度有所减缓。     

食品安全呼唤物联网技术的运用和普及

《食品安全法》实施以来,食品安全事件依旧层出不穷,建立食品追溯系统需要物联网技术的运用和普及,以期实现对食品生产、加工、运输、包装、储存等方面质量问题的监管,理论上实现对食品从农田到餐桌的全面监控。     

北方地区表流人工湿地冬季污水脱氮效果及微生物分布分析

对北方地区表流人工湿地冬季脱氮效果及微生物分布情况进行了分析,以西安皂河试验人工湿地为例。结果表明,表流人工湿地在北方地区冬季取得较好的脱氮效果,总氮与氨氮的平均去除率分别为47.76%、58.49%,并且氨化细菌沿程呈现递减的变化趋势,而亚硝化细菌呈现递增的趋势,但反硝化菌呈现先降后升的趋势。氨氮质量浓度与氨化细菌数及亚硝化细菌数之间存在显著相关,而硝氮质量浓度与反硝化细菌之间的相关性不显著。这结果说明除了硝化-反硝化的脱氮机制外还存在其他的脱氮机制。     

Guaranteed cost distributed fuzzy observer‐based control for a class of nonlinear spatially distributed processes

The guaranteed cost distributed fuzzy (GCDF) observer‐based control design is proposed for a class of nonlinear spatially distributed processes described by first‐order hyperbolic partial differential equations (PDEs). Initially, a T–S fuzzy hyperbolic PDE model is proposed to accurately represent the nonlinear PDE system. Then, based on the fuzzy PDE model, the GCDF observer‐based control design is developed in terms of a set of space‐dependent linear matrix inequalities. In the proposed control scheme, a distributed fuzzy observer is used to estimate the state of the PDE system. The designed fuzzy controller can not only ensure the exponential stability of the closed‐loop PDE system but also provide an upper bound of quadratic cost function. Moreover, a suboptimal fuzzy control design is addressed in the sense of minimizing an upper bound of the cost function. The finite difference method in space and the existing linear matrix inequality optimization techniques are used to approximately solve the suboptimal control design problem. Finally, the proposed design method is applied to the control of a nonisothermal plug‐flow reactor. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2366–2378, 2013     

表面流人工湿地对高含量有机污染河水的去除效果研究

利用不同植物(芦苇、香蒲)表流人工湿地处理高含量有机污染河水的研究。结果表明,当水力负荷为0.041m3/(d.m2),进水COD和BOD5分别为178.9～480.2 mg/L和40.75～225.6 mg/L,最大去除效果分别可达到93.64%和99.25%。出水COD低于90 mg/L,BOD5低于22 mg/L,均达到GB 18918-2002排放二级标准。高含量有机污水进入表面流人工湿地之后,有机物有效去除长度为32 m,其中发挥主要作用的场所是距进水点21 m以内的区域。表面流人工湿地中,芦苇床和香蒲床对高含量有机污染物去除效果无明显差异,它们根际和根区细菌总数差别不大。     

关于校企联合培养工科专业学生创新能力的思考——以吉首大学为例

以吉首大学环境工程专业为例,对传统实践教学的现状和存在的问题进行了剖析,对校企联合培养工科学生创新能力的意义进行了分析。针对地方高校工科专业毕业生普遍实际动手能力不足、创新能力欠缺的现状,提出了校企联合培养工科专业学生创新能力的几种形式。     

吹膜挤出机的电磁感应加热系统建模与有限元模拟研究

为实现吹膜挤出机在电磁感应加热条件下能效的定量分析,对吹膜挤出机电磁感应加热的三维有限元模型进行了研究,导出了对应于指定机筒和螺杆材料的电流透入深度与电磁感应加热器的各设计参数之间的关系;分析了挤出机的机筒与螺杆等关键部件在电磁感应三段式分区加热条件下的磁场分布、电流密度场分布及焦耳热能分布的相对趋势。结果表明,感应磁场主要分布在机筒内表面,而相应的感应电流主要分布在机筒外层,且当机筒上缠绕的3组匝数相同的电磁感应加热线圈中加载有大小相等、方向相同的交变电流时,电流密度和产生的焦耳热能集中在机筒和螺杆的中部,而适当增加进料段与计量段加热区所对应的两组线圈匝数可获得较为均匀的电磁感应加热效果。相对于电阻式加热,电磁感应加热的能量损耗较小,是一种环保节能的吹膜挤出机加热方式。     

Thermal properties and crystallization behavior of bamboo fiber/high‐density polyethylene composites: Nano‐TiO2 effects

In this study, bamboo fiber/high‐density polyethylene (HDPE) composites were prepared, and the effects of nano‐TiO₂ on their thermal properties and crystallization behavior were investigated via thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results show that the addition of nano‐TiO₂ improved the thermal stability and had a dual function in the crystallization behavior of the composites. On one hand, it functioned as a nucleating agent. The addition of 2 wt % nano‐TiO₂ promoted the crystallization, which caused the increase of the crystallization rate and crystallinity degree, as well as the micronization of the crystalline grain. On the other hand, intermolecular hydrogen bonds and covalent bonds were formed between nano‐TiO₂ and the polymer matrix, which hindered the crystallization of the composites. When the content of nano‐TiO₂ was continually increased, the inhibitory effect of the crystallization was gradually enhanced, which resulted in a decrease in the crystallization rate and crystallinity degree of the composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39846.