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991.
The extraction of aluminum from coal mining waste (CMW) is an important industrial process. The two major problems in applications are low aluminum dissolution efficiency and high iron content in the raw material, which affect the quantity and quality of products. To improve the aluminum recovery process, the leaching kinet-ics of CMW with hydrochloric acid was studied. A shrinking core model was used to investigate aluminum and iron dissolution kinetics. Based on the kinetic characteristics, a process for recovering aluminum was proposed and tested experimental y. It is found that the aluminum leaching reaction is controlled by surface reaction at low temperatures (40–80 °C) and by diffusion process at higher temperatures (90–106 °C). The iron dissolution process is dominated by surface reaction at 40–100 °C. The results show that iron could be dissolved or separated by concentrated hydrochloric acid. Fine grinding wil improve aluminum dissolution significantly. 相似文献
992.
双功能受阻胺光稳定剂GW-540与紫外线吸收剂并用效应的研究 总被引:4,自引:0,他引:4
本文用IR、UV、SEM等方法,研究了双功能基受阻胺光稳定剂——三(1,2,2,6,6-五甲基-4-哌啶基)亚磷酸酯(GW-540),与紫外线吸收剂UV-531、UV-327并用时对聚丙烯的防光作用,结果表明:GW-540-UV-531并用体系有良好的防光作用,呈强的协同效应;GW-540-UV-327并用体系呈弱的对抗作用。结果还表明:GW-540对531和327的光分解均有保护作用.电镜研究表明,加入GW-540后,使UV-327在聚丙烯中分散更不均匀,从而影响其效率的发挥。文中提出了两个体系的协同和对抗作用机理。 相似文献
993.
Shu-lin Xiao Xu Du Li Qin Cui-hong He Guang-hua Cui 《Journal of Inorganic and Organometallic Polymers and Materials》2012,22(6):1384-1390
Two one-dimensional Cd(II) coordination polymers constructed by ribbon-like molecules, {[Cd(L1)2(NO3)]·NO3} n (1) (L1 = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)benzene) and [Cd(L2)2(NO3)2] n (2) (L2 = 1,3-bis(benzimidazol-1-yl)benzene) have been obtained through assembly of the two structurally similar flexible bis(benzimidazole)-based ligands and cadmium nitrate tetrahydrate. The cadmium(II) centers display different coordination environments with trigonal-bipyramidal geometry in 1, and a octahedral geometry in 2. Weak C–H···O interactions in 1 result in a two-dimensional supramolecular layer; two π–π interactions are present in 2 forming a three-dimensional supramolecular network structure. The solid state fluorescence properties of 1 and 2 were investigated. 相似文献
994.
Qi Zhang Ruilin Zheng Jianyong Ding Peng Cui Zhongyue Wang Peng Lv Wei Wei 《Journal of the American Ceramic Society》2021,104(7):3260-3268
Thermally robust and highly efficient green-emitting luminescent ceramics are gradually attracting great attention as promising phosphors using in high-brightness laser phosphor display to reduce serious speckle noise as well as high cost. However, lumen density is still seriously restricting their potential applications especially under high-power density laser due to insufficient absorption of blue laser and significant thermal quenching. Here, we report an Al2O3-LuAG: Ce composite ceramic phosphor (CCP) for high-brightness laser phosphor display. Owing to good optical properties and high thermal conductivity of Al2O3, the Al2O3-LuAG: Ce CCP shows high photoluminescence quantum yield (79.6%), low thermal quenching (only 3.2% loss in luminescence at 200°C), and high thermal conductivity (18.9 W·m−1·K−1). Moreover, the Al2O3, as scattering centers, enhances the Rayleigh–Mie scattering of the blue laser, and hence the absorption of the Al2O3-LuAG: Ce CCP exhibits a remarkable improvement (~2.3 times) at 450 nm. Finally, with optimized thickness (0.3 mm) of Al2O3-LuAG: Ce CCP, an excellent luminous efficiency (216 lm·W−1) and outstanding lumen density (6129 lm·mm−2) of the green-emitting light source was obtained by driving under a high-power density (28.33 W·mm−2) blue laser. All of those validate the suitability of the Al2O3-LuAG: Ce CCP for high-brightness display. 相似文献
995.
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998.
A series of ethylene-vinyl acetate copolymers, EVA, containing 0-40% VA and three organoclays, M2(HT)2, M3(HT)1 and (HE)2M1T1, were melt processed to explore the relationship between the polarity of the polymer matrix and the organoclay structure on the extent of exfoliation and properties of the resulting nanocomposites. The degree of exfoliation of the nanocomposites was evaluated by TEM, WAXS, and mechanical testing. Quantitative particle analyses of TEM images were made to give various averages of the clay dimensions and aspect ratio. The results from different techniques were generally consistent with each other. These EVA copolymer nanocomposites show dramatically improved exfoliation of the organoclay as the VA content is increased. Nanocomposites based on the organoclay with two alkyl tails always gave better exfoliation than those based on the organoclays with a single tail at all VA levels; however, the relative advantage of the two tails versus one tail seems to diminish with increased VA level. The predictions of tensile modulus using a simple composite model based on Halpin-Tsai equations show rather good agreement with the experimental data. 相似文献
999.
Effects of surface modification of carbon nanofibers on the mechanical properties of polyamide 1212 composites
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In this study, the effects of carbon nanofiber (CNF) surface modification on mechanical properties of polyamide 1212 (PA1212)/CNFs composites were investigated. CNFs grafted with ethylenediamine (CNF‐g‐EDA), and CNFs grafted with polyethyleneimine (CNF‐g‐PEI) were prepared and characterized. The mechanical properties of the PA1212/CNFs composites were reinforced efficiently with addition of 0.3 wt % modified CNFs after drawing. The reinforcing effect of the drawn composites was investigated in terms of interfacial interaction, crystal orientation, crystallization properties and so on. After the surface modification of CNFs, the interfacial adhesion and dispersion of CNFs in PA1212 matrix were improved, especially for CNF‐g‐PEI. The improved interfacial adhesion and dispersion of CNFs in PA1212 matrix was beneficial to reinforcement of the composites. Compared with pure PA1212, improved degree of crystal orientation in the PA1212/CNF‐g‐PEI (CNF‐g‐EDA) composites was responsible for reinforcement of mechanical properties after drawing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41424. 相似文献
1000.
Synthesis and Solution Properties of a Double‐Tailed Quaternary Ammonium Surfactant with a Protrudent Head Group
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Binglei Song Zonghui Xu Xiaona Yu Shuyi Chen Shunan Li Rongzhen Shi Zhenggang Cui 《Journal of surfactants and detergents》2015,18(6):1081-1088
Modification of the molecular structure of surfactants is an effective method for exploring their self‐assembly. A double‐tailed quaternary ammonium surfactant with a protrudent head group, namely 2‐octyldecyltrimethylammonium bromide (2‐ODTAB) was synthesized, and the solution properties were investigated by surface tension, dynamic light scattering, and cryogenic TEM. A comparative study was also performed on the traditional double‐tailed homologue surfactants dioctyldimethylammonium bromide (8–8), didecyldimethylammonium bromide (10–10), and didodecyldimethylammonium bromide (12–12). The results showed that 2‐ODTAB was more effective at lowering surface tension and in forming stable vesicles than traditional double‐tailed surfactants with similar alkyl chain length. The reason is attributed to the improved structure of 2‐ODTAB, in which the two alkyl tails are connected to the ionic head group by one carbon atom. This structure imparts more freedom to the head group and thus favors formation of more stable aggregates at low concentration. In addition, the lower limit of the alkyl chain length of the double‐tailed surfactants for forming stable vesicles was illustrated. 相似文献