Electrochemical characteristics of porous TiO2 encapsulated silicon anode

TiO₂ coated silicon, which was prepared by the modified sol–gel method, was employed as the anode material for lithium secondary batteries and the relationship between the diffusivity and electrochemical characteristics was investigated. The results showed that the physical properties of the samples, such as their diffusivity and pore size distribution, enhanced the cycling efficiency of the TiO₂ coated silicon, probably due to the reduction of the side reactions, which may be closely related to the pore size distribution of the TiO₂ coating layer. The pore size of the coating layer plays an important role in retarding the lithium ion diffusion. In the experimental range studied herein, higher capacity retention was exhibited for the TiO₂ coated silicon prepared at pH 10.7.     

Heat transfer in three-phase (G/L/S) circulating fluidized beds with low surface tension media

Characteristics of heat transfer were investigated in a three-phase circulating fluidized bed whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of gas and liquid velocities, particle size (0.5–3.0 mm), solid circulation rate (2.0–6.5 kg/m² s), and surface tension (47.53–72.75×10⁻³ N/m) of liquid phase on the heat transfer coefficient were examined. It was found that the heat transfer coefficient (h) between the immersed vertical heater and the riser proper of the three-phase circulating fluidized bed increased with increase in gas and liquid velocities, but did not change considerably with a further increase in liquid velocity, even in the higher range. The value of heat transfer coefficient increased gradually with increase in the size of fluidized solid particles without exhibiting the local minimum, which represented that there was no bed contraction in three-phase circulating fluidized beds due to the higher liquid velocity. The heat transfer system could attain a stabilized condition more easily with increase in particle size. The value of heat transfer coefficient increased with increase in solid circulation rate in all the cases studied due to the increase of solid holdup in the riser. The value of heat transfer coefficient decreased with increase in surface tension of liquid phase, due to the decrease of bubbling phenomena and bubble holdup. The decrease in liquid surface tension could lead to an increase in elapsed time from which the temperature difference between the heater surface and the riser became an almost constant value. The experimentally obtained values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.     

玻璃窑炉烟气脱硝脱硫除尘一体化技术

针对玻璃窑炉烟气特性和排放情况以及脱硝脱硫除尘一体化技术进行了介绍,并通过实际案例分析,对玻璃窑炉的烟气处理提出了针对性的一体化解决方案。     

层次分析法(AHP)在军团菌杀灭方法评判中的应用

该文利用层次分析法(AHP)对军团菌杀灭方法进行综合评判。以中央空调循环冷却水系统为例,建立评价指标系统,对军团菌控制效果以及化学杀生剂进行综合评价,由此得到化学法是最适于中央空调循环冷却水系统的杀菌方法。其中军团菌特效杀菌剂的杀菌性能最佳,可作为应急处理药剂,二氧化氯、2,5-二溴海因、二氯异氰尿酸可作为日常处理药剂。在条件允许的情况下,可使用臭氧作为处理药剂。     

中空玻璃微珠/纳米TiO_2/PE复合材料的隔热性能与结构的关系

采用中空玻璃微珠(GB)、纳米TiO2单独或复合填充聚乙烯(PE),研究了GB、纳米TiO2含量对复合材料光反射性能和隔热性能的影响。结果表明:GB、纳米TiO2的加入明显提高了PE的反射性能和隔热性能;当GB/PE、TiO2/PE复合材料的比例分别为2/7、1/7时,两种复合材料综合隔热性能达到最佳值,与纯PE相比,辐照5 min后阻隔密室的升温幅度分别下降了16.8℃和16℃,GB与纳米TiO2具有协同隔热作用,GB/PE、TiO2/PE、TiO2/GB/PE 3种复合材料中,GB/TiO2/PE(2/1/7)体系的隔热性能最好,辐照5 min后阻隔密室的升温幅度只有6.8℃比,纯PE下降了22.4℃。     

复合絮凝剂的研究进展及应用

复合絮凝剂根据成分的不同可分为无机高分子复合絮凝剂、有机复合絮凝剂以及无机-有机复合絮凝剂3类.综述了复合絮凝剂的国内外研究进展,并对各种复合絮凝剂的优缺点及应用领域进行了对比分析,指出无机-有机复合絮凝剂将是今后的研究重点,而工业废物资源化制备复合絮凝剂将是未来的重要生产途径.     

基于模糊评判的倾斜中厚矿体采矿方法优化选择

开磷集团马路坪矿段倾斜中厚矿体的开采为世界性采矿难题,国内外目前尚无高效开采此类矿体的方法.针对矿体开采技术条件,提出了5种可行的开采方案,并采用模糊综合评判方法对各开采方案进行优化选择,将各开采方案的评价指标进行量化分析,确定出适合马路坪矿区开采的最佳方案为脉外与脉内联合采准嗣后充填采矿法.     

Hydrogenation of CO2 to formic acid on supported ruthenium catalysts

We report on the preparation and application of novel heterogeneous supported ruthenium catalysts. The catalysts are active in the synthesis of formic acid from the hydrogenation of carbon dioxide and are characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction analysis and transmission electron microscopy. Abundant hydroxyl groups, which interact with the ruthenium components, play an important role in the catalytic reactions. Highly dispersed ruthenium hydroxide species enhance the hydrogenation of CO₂, while crystalline RuO₂ species, which are formed from the relatively high ruthenium content or the pH of the solution during preparation of the catalyst, restrict the production of formic acid. Optimal activity of ruthenium hydroxide as a catalyst for the hydrogenation of CO₂ to formic acid is achieved over a γ-Al₂O₃ supported 2.0 wt% ruthenium catalyst, which is prepared in a solution of pH 12.8 with NH₃·H₂O as a titration solvent. A possible hydrogenation mechanism for the hydroxide ruthenium catalyst is proposed.     

Effect of repetitive processing on the mechanical properties and fracture toughness of dynamically vulcanized iPP/EPDM blends

The effect of repetitive processing on the mechanical properties and fracture toughness of dynamically vulcanized isotactic polypropylene/ethylene‐propylene‐diene rubber blends (TPVs) with and without addition of β‐nucleating agent (β‐NA) was studied. The results showed that the repetitive processing did not cause much loss in the mechanical properties of TPVs, especially for TPVs with β‐NA, and TPVs with β‐NA showed better performance stability than TPVs without β‐NA. Essential work of fracture (EWF) approach was used to study the fracture behavior, and the results showed that the value of w_e (the specific essential work of fracture) of TPVs without β‐NA showed a significant decrease while that of TPVs with β‐NA almost kept constant after repetitive processing. Differential scanning calorimetry and wide‐angle X‐ray diffraction were used to study the variation of crystalline structures, and the results indicated that the repetitive processing showed no significant influence on the crystalline structures of TPVs, and the β‐NA maintained high‐nucleating efficiency after repetitive processing. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010