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A combination of suspension polymerization and postcrosslinking was used to prepare hypercrosslinked polystyrene (H‐PS) microspheres with controllably bimodal pore size distribution in the presence of toluene and polypropylene (PP) as a coporogen. The proportion of PP in the coporogen was changed to investigate the influence of the coporogen composition on the pore structure of the H‐PS microspheres. The addition of a small amount of PP achieved the aim of a clearly bimodal pore size distribution and the control of the macroporosity of the H‐PS microspheres, which have potential application in the preparation of catalyst supports. The specific surface area of the H‐PS microspheres could be adjusted in the range 380–790 m2/g by changes in the concentration of PP in the coporogen. Moreover, the H‐PS microspheres displayed all the characteristics of Davankov‐type resins by their ability to be swollen in both thermodynamically poor solvents such as water and good solvents such as toluene. Finally, the possible mechanism of porosity formation during polymerization and postcrosslinking was also examined by a combination of pore structure data and the appearance of the microspheres before and after postcrosslinking. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
994.
J. J. Huo Y. S. Du G. Cheng X. F. Wu L. Li Z. C. Xia G. H. Rao 《Journal of Phase Equilibria and Diffusion》2018,39(2):152-165
Isothermal section of Fe-Gd-Pd ternary system at 873 K has been established by means of x-ray diffraction (XRD), differential scanning calorimetry (DSC), and scanning electron microscope (SEM) with energy disperse x-ray spectroscopy (EDS) in backscattered electron imaging modes. The isothermal section consists of 14 single-phase regions, 25 two-phase regions, and 12 three-phase regions. At 873 K, no ternary compound was found and the binary inermetallic compounds Gd3Pd and Fe23Gd6 are not stable, whereas the compound Fe23Gd6 decomposes into compounds Fe17Gd2 and Fe3Gd. The XRD and the SEM/EDS analysis show that there is almost no solubility of Gd in the FePd and FePd3 phases, and the solubilities of Pd in Fe17Gd2, Fe3Gd and Fe2Gd and Fe in GdPd2, α-Gd3Pd4 and Gd3Pd2 are all less than 1 at.%. Meanwhile, the solubilities of Fe in GdPd3, α-GdPd and Gd7Pd3 are determined to be as high as 1.37, 5.31, and 4.18 at.% Fe, respectively. 相似文献
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Nanhang Dong Ruiqiang Huo Ming Liu Lisheng Deng Zhengbing Deng Guozhang Chang Zhen Huang Hongyu Huang 《中国化学工程学报》2021,29(1):335-343
Chemical looping gasification (CLG) provides a novel approach to dispose the sewage sludge. In order to improve the reactivity of the calcined copper slag, NiO modification is considered as one of the good solutions. The copper slag calcined at 1100 ℃ doped with 20 wt% NiO (Ni20-CS) was used as an oxygen carrier (OC) in sludge CLG in the work. The modification of NiO can evidently enhance the reactivity of copper slag to promote the sludge conversion, especially for sludge char conversion. The carbon conversion and valid gas yield (Vg) increase from 67.02% and 0.23 m3·kg-1 using the original OC to 78.34% and 0.29 m3·kg-1 using the Ni20-CS OC, respectively. The increase of equivalent coefficient (Ω) facilitates the sludge conversion and a suitable Ω value is determined at 0.47 to obtain the highest valid gas yield (0.29 m3·kg-1). A suitable steam content is assigned at 27.22% to obtain the maximum carbon conversion of 87.09%, where an acceptable LHV of 12.63 MJ·m-3 and Vg of 0.39 m3·kg-1 are obtained. Although the reactivity of Ni20-CS OC gradually decreases with the increase in cycle numbers because of the generation of NiFe2O4-δ species, the deposition of sludge ash containing many metallic elements is beneficial to the sludge conversion. As a result, the carbon conversion shows a slight uptrend with the increase of cycle numbers in sludge CLG. It indicates that the Ni20-CS sample is a good OC for sludge CLG. 相似文献
998.
通过阻温测试、介温测试及XRD等测试分析手段,研究了CuO的加入对BaTiO3基PTC材料性能的影响,结果表明:加入0.1mol%的CuO可以明显改善材料的PTC效应,升阻比提高到106;CuO的加入可明显降低烧结温度,当CuO的加入量为4mol%时,烧结温度降低65℃,最低烧结温度为1210℃;加入2.0mol%的CuO,材料的居里温度提高了近40℃,同时CuO的加入能提高材料的介电常数,并有压峰作用,对高介电常数材料的研究有一定的意义。 相似文献
999.
Ba1.5Sr1.5Co2-xZnxFe22O41(x = 0,0.4,0.8,1.2,1.6,2.0) hexaferrites substituted by Zn were prepared via conventional solid-state reaction. The influences of Zn substitution content on phase formation, microstructure, and magnetic properties, especially high-frequency magnetic properties, were systematically investigated. Results indicate that, when sintering temperature is 1200 °C, pure ferrite phase of Co2Z is formed, and Zn2+ is successfully incorporated into the lattice. Appropriate amount of Zn substitution can improve the densification and saturation magnetization () of Z-type ferrite, thereby effectively promoting permeability. However, due to limitations of Snoek's law, cut-off frequency is found to be reduced with Zn substitution. For x = 0.4, the sample exhibits both high permeability (up to 22.49) and high cut-off frequency (~900 MHz), with Snoek constant reaching 19.337 GHz. Furthermore, magnetic loss for the sample with x = 0.4 is found to be low. It is anticipated that this material will have extensive application prospects for miniaturization and high frequency antenna applications. 相似文献
1000.
利用热膨胀相变仪研究了不含Cr和含0.3%(质量分数)Cr的叉车门架用20MnSiV钢的连续冷却转变行为,通过光学显微镜观察试验钢在不同冷速下的显微组织,并检测其维氏硬度,得到了试验钢的动态连续冷却转变(CCT)曲线.结果表明,0.1~10℃/s的冷速范围内,试验钢在添加0.3%Cr后,贝氏体转变的临界冷速降低,综合力... 相似文献