二氧化氯预氧化除铁过程中亚氯酸根作用的实验研究

将ClO_2-ClO_2~-作为整个控制体系,通过模拟试验,研究二氧化氯预氧化除铁过程中亚氯酸根浓度变化及其发挥氧化性能除铁的影响因素。结果表明:pH值是二氧化氯投加量和亚氯酸根发挥氧化效能的重要影响因素,pH值越低亚氯酸根的氧化效能越低,生成亚氯酸根越多。当pH值较高时,二氧化氯只需按照理论投加量(即[ClO_2]/[Fe~(2 )]= 0.242),亚氯酸根便能充分发挥其氧化效能,亚氯酸根不会形成累积。实验表明:铁的初始浓度为2～9mg/L,5.8≤pH≤6.6时,0.242≤[ClO_2]/[Fe~(2 )]≤0.387时,能有效地将水中的铁离子降到0.3mg/L以下。     

基于群体动力学的协同过滤算法及应用

针对传统协同过滤算法稀疏矩阵和推荐精度不高的问题,根据一种社会心理学模型提出了基于群体动力学的协同过滤算法.该算法综合考虑了个体因素和环境因素对用户评分行为的影响,以此来调整传统的评分预测方法,然后为用户进行推荐.实验结果表明,该算法可以明显地提高推荐的精确度,有效地缓解稀疏矩阵问题;同时该算法还可以有效减少积累误差.最后将该算法成功运用在西安景点的推荐服务上.     

低温流动改进剂在柴油蜡晶生长阶段对蜡晶形貌的控制作用

采用实验和分子动力学模拟相结合的方法,考察了多种乙烯-醋酸乙烯酯(EVA)和聚甲基丙烯酸酯(PMA)类低温流动改进剂(CFI),对蜡晶晶体形貌的影响。结果表明,蜡晶的各个晶面在附着了CFI后,其吸引烃分子的能力均有不同程度的增强,各晶面的相对生长速度也将随之改变。蜡晶(001)面相对生长速度增加的越显著,越有利于蜡晶晶体形貌由片状转变为近似四棱柱状甚至双锥状,从而使蜡晶粒径减小,并减弱晶粒间的相互作用,提高蜡晶分散度,更显著的改善柴油低温流动性能。     

Guerbet十四醇的合成与表征

以正庚醇为原料 ,通过Guerbet反应合成Guerbet十四醇 (2 戊基壬醇 ,C14 GA)。用IR、NMR和元素分析测定了C14 GA的结构 ,并研究了反应温度和用料比对其产率的影响。实验结果如下 :(1)在较优化的反应条件下 (正庚醇的总加入量为 1mol,在实验过程中 ,先加入 1/ 3mol庚醇和 1/ 4mol的KOH ,在 16 0℃下反应 2h ,然后再加入剩下的 2 / 3mol庚醇和 4g 5 %Pd -C催化剂 ,在 15 5℃下反应 6h)合成产物 ,其产率可达到 5 4 2 0 % ;(2 )所合成的产物与试图要得到的Guerbet十四醇 (2 戊基壬醇 ,C14 GA)含有相同的基团 (2×—CH3、10×—CH2 —、1×CH、1×—CH2 —O—和 1×—OH) ,而且 ,所合成的产物中 ,w (C) =79 0 6 % ,w (H ) =13 6 2 % ,与从Guerbet十四醇分子式计算的理论值w(C) =78 5 0 % ,w (H) =14 0 1%基本一致。可见所合成的产物正是Guerbet十四醇 (C14 GA)     

超声波与其他技术联用降解有机物的研究进展

介绍了国内外超声波与其他技术联用在降解水中有机污染物方面的研究进展。多项研究表明,超声波与Fenton型试剂、紫外光、铁、生物催化剂、电解、臭氧等手段联用可大大提高有机物降解率,应用前景广阔。     

Vitamin A microencapsulation within poly(methyl methacrylate)‐g‐polyethylenimine microspheres: Localized proton buffering effect on vitamin A stability

To stabilize vitamin A in a cosmetic/dermatological formulation, we present here a new encapsulation method based on polymer microspheres having a localized “proton‐buffering” capacity. Poly(methyl methacrylate)‐g‐polyethylenimine (PMMA‐g‐PEI) was prepared by direct condensation grafting of PEI onto poly(methyl methacrylate‐co‐methyl acrylic acid). The reaction was confirmed by FT‐IR analysis showing the amide vibration at 1,550 cm^?1. Elemental analysis indicated that the weight content of the grafted PEI was 1.6% (w/w). Vitamin A was encapsulated into PMMA‐g‐PEI microspheres by using an oil‐in‐water (O/W) single emulsion method. The presence of PEI moiety dramatically improved the chemical stability of vitamin A in microspheres. Vitamin A encapsulated within PMMA‐g‐PEI microspheres maintained 91% of its initial activity after 30‐day incubation at 40°C, while only maintaining 60% within plain PMMA microspheres. This study demonstrates that proton‐buffering within hydrophobic polymer matrix is a useful strategy for stabilizing “acid‐labile” active ingredients. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 517–522, 2004     

Surface morphology control of immiscible polymer-blend thin films

The effects of the molecular weights (molecular weight of polystyrene, M_w,PS, varying from 2.9 to 129 k) on the surface morphologies of spin-coated and annealed polystyrene/poly (methyl methacrylate) (PS/PMMA=50/50, w/w) blend films were investigated by atomic force microscopy and X-ray photoelectron spectroscopy. For the spin-coated films, when the M_w,PS varied from 2.9 to 129 k, three different kinds of surface morphologies (a nanophase-separated morphology, a PMMA cellular or network-like morphology whose meshes filled with PS, a sea-island like morphology) were observed and their formation mechanisms are discussed, respectively. Upon annealing, two different morphology-evolution processes were observed. It is found that a upper PS-rich phase layer is formed when M_w,PS<4 k, and this behavior is mainly attributed to the low interfacial tension between PS and PMMA component. When M_w,PS>4 k, the PS-rich phase forms droplets on top of the PMMA-rich phase layer which wets the SiO_x substrate. These results indicate that the surface morphology of the polymer blend films can be controlled by the polymer molecular weight and annealing conditions.     

Industrial TiO2 based nacreous pigments as functional building materials: Photocatalytic removal of NO

In this paper, the photocatalytic activity of industrial titanium dioxide (TiO₂) based nacreous pigments was researched as functional building materials for photocatalytic NO remove. Three industrial TiO₂ based nacreous pigments were selected to estimate the photocatalytic activity for NO remove. This study is a good proof that pearlescent pigments can eliminate NO, and its performance is positively correlated with its titanium dioxide content. And this research will widen the application of nacreous pigments in functional building materials, and provide a new way to eliminate in door nitric oxide pollution.     

Quantitative Analysis of Zinc Vaporization from Manganese Zinc Ferrites

Zinc vaporization of Mn-Zn ferrites was quantitatively characterized in terms of oxygen partial pressure P _O2, temperature, grain size and sample geometry. The amount of zinc loss was measured as a function of time at various temperatures by a thermogravimetric method. The weight loss due to irreversible zinc vaporization showed a linear behavior with time and increased exponentially with temperature. The observed weight loss due to zinc evaporation at 1100°C was small, whereas a significant weight change was detected at 1200°C. The weight loss was even greater in a reducing atmosphere ( P _O2= 5 × 10⁻⁵). Below 1300°C, the diffusion of elemental zinc was sufficiently fast to compensate the zinc loss at the interface region, resulting in a linear dependence on time. At temperatures ≥1400°C, the weight change no longer followed the linear dependence and showed a rather parabolic behavior with a concave upward slope. The core shape and the gas flow around ferrite cores were important factors that affected the rate of zinc vaporization, but not the grain size.     

液体消毒洗涤剂的研制

研制了具有消毒杀菌、洗涤去污双重功效的液体消毒洗涤剂 ,测定了其对金黄色葡萄球菌的杀灭效果。结果表明 ,消毒洗涤剂的杀菌效果随其浓度的增加 ,作用时间的延长而提高 ;戊二醛浓度为 2 0 0× 10 -6时 ,与金黄色葡萄球菌作用 5min ,杀灭率可达 99.99%。将消毒洗涤剂在室温下放置半年 ,戊二醛分解率为 17.3 1%