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951.
《分离科学与技术》2012,47(2):305-319
Abstract Although gel permeation chromatography is firmly established as a technique for investigating heterogeneity in synthetic polymers, the character of the chromatographic process-whether it is dominated by diffusion, by flow effects, or by an equilibrium partitioning of polymer between the mobile phase and the micropores in the column packing-is still disputed. General chromatographic theory supports the idea that under ordinary experimental conditions the equilibrium distribution of a solute determines the position of its elution peak in the chromatogram. Statistical mechanical calculations of distribution coefficients for linear and branched polymer chains and idealized pores of simple geometry lead to predictions in good accord with some experimental findings. 相似文献
952.
《分离科学与技术》2012,47(14):3217-3228
Abstract Polyaluminum Silicate Chloride (PASiC) is a new water treatment coagulant. It contains silica that can be hydrolyzed to produce SiO2 as coagulant aid. Hence, this coagulant consumes little alkalinity and is effective at low dosages. It is, therefore, especially suitable for treating water of low alkalinity and low turbidity. When manufacturing PASiC, the alkalinity solution involved in the polymeric reaction must be added slowly to the aluminum salt solution to avoid local over‐saturation which enhances the production of high‐valence medium polymer species (Alb) (e.g. Al12AlO4(OH)24 7+, Al13). In this research, the use of an ultrasonic vibrating system to assist the alkalinity dosing during the formation of PASiC was studied. The ultrasonic vibrating system breaks up the NaOH solution into fine mists so that the latter can be more evenly dispersed into the aluminum silica solution to avoid local over‐saturation. This ultrasonic‐assisted NaOH dosing method leads to a more stable polymerization of aluminum changing ratios of Ala, Alb, and Alc in the final product and raising the Alb portion in the coagulant. Long‐term observations also show that PASiC prepared with the ultrasonic‐aided NaOH dosing at 0.25 mL/min is more effective in removing turbidity. 相似文献
953.
Toshiaki Arai Narihiro Morosawa Kazuhiko Tokunaga Yasuhiro Terai Eri Fukumoto Takashige Fujimori Tatsuya Sasaoka 《Journal of the Society for Information Display》2011,19(2):205-211
Abstract— The stability and reliability of oxide‐semiconductor TFTs were investigated. The contact material to the oxide semiconductor affected the thermal stability of the TFT, and a molybdenum‐contact source/drain showed good stability. And the passivating film and TFT structure affected the stability against bias stress and humidity stress, and dc‐sputtered Al2O3 passivation and fully covered channel structure with an etching stopper or source/drain showed good reliability. Moreover, high photo‐stability was confirmed by the bias‐enhanced photo‐irradiation stress test. An 11.7‐in.‐diagonal qHD AMOLED display was demonstrated to provide an applicable solution for a large‐sized OLED and an ultra‐high‐definition LCD‐TV mass production. 相似文献
954.
Fe3Al金属间化合物堆焊材料的应用 总被引:6,自引:0,他引:6
采用东南大学研制的Fe3Al基合金的成分配方研制的堆焊材料成功堆焊18-8系不锈钢,形成了完整的焊接工艺和工艺参数,为Fe3Al的应用开辟了一条新的途径,取得了明显的经济效益。 相似文献
955.
X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and electron spin resonance (ESR) have been used to characterize a series of Cu/Al2O3 catalysts. The information obtained from surface and bulk characterization has been correlated with CO and CH4 oxidation activity of the catalysts. For catalysts with Cu/Al atomic ratios 0.051, XPS data indicated that most of the Cu was present as a dispersed surface phase. ESR results showed that the ratio of isolated/interacting copper surface phase decreased with increasing Cu content. For catalysts with Cu/Al atomic ratio 0.077, large CuO crystallites were detected by XRD. XPS results indicated that Cu dispersion decreased with increasing Cu content. The turn over frequency (TOF) for CO oxidation increased with increasing Cu content. This has been attributed to an increase in the amount of crystalline CuO present in the catalysts. The TOF for CH4 oxidation decreased with increasing Cu content up to Cu/Al = 0.051. This was paralleled by a significant decrease in the relative Cu ESR signal measured for the catalysts. We propose that the isolated Cu surface phase is more active for CH4 oxidation than the interacting copper surface phase or crystalline CuO. CH4 oxidation activities were similar for the catalysts with Cu/Al atomic ratio 0.077. 相似文献
956.
An analytical expression analogous to the D2 law was introduced, based on a mass transfer consideration, to describe the evaporation of pure droplets in the convective regime based on the Ranz-Marshall-type correlation for the Sh number. Comparison was made to single droplet drying experiments of pure water. It was found that the effect of mass transfer coefficient depression is significant under the high mass flux condition from the droplet. An expression was obtained to approximate the total time required for complete evaporation of a pure droplet. This expression can be used as a quick computation tool for more fundamental studies on droplet evaporation under controlled ambient conditions. 相似文献
957.
介绍组合压力模在铝包钢丝拉拔中的使用 ,讨论压力套管与压力模的结合方式 ,结果显示通过改进压力套管可提高生产效率、成材率、产品质量 ,降低辅料消耗 相似文献
958.
稀土合金具有变质、晶粒细化和净化铝合金的综合功能,而且对周围环境不产生任何污染。充分发挥稀土合金的特殊功能,形成一种绿色的复合变质细化和净化为一体的铸造铝合金熔体处理工艺,从源头上解决铸造铝合金熔体处理过程中的环保问题,为铸造铝合金绿色清洁集约化生产提供了一条可行之路。 相似文献
959.
Production of high strength Al-Zn-Mg-Cu alloys by spray forming process 总被引:15,自引:2,他引:13
1 INTRODUCTIONAl Zn ( 7×××series)alloyshavebeenwidelyusedbecauseofhighstrength ,corrosion resistanceandothergoodproperties[1 ,2 ] .Butapracticalcontentlimitof7%Zn (alloys 70 75,71 75and 7475etc)isimposedforconventionalcastmaterialsbecauseofso lutemacro segregationandcoar… 相似文献
960.
研究了热处理对Ni-P -Al2 O3 复合化学镀层性能的影响。结果表明 ,Ni-P -Al2 O3 复合化学镀层的硬度和耐磨性随加热温度的升高而升高 ,并在 40 0℃时达到最大值。镀层的耐蚀能力随加热温度的升高而降低 ,但当加热温度超过 45 0℃后 ,耐蚀能力又会明显提高 相似文献