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Chen Tang Tiehu Li Yuhang Bai Junjie Gao Wenbo Yang Shasha Jiao Tingkai Zhao 《Ceramics International》2018,44(10):11812-11819
Recently, ceramic matrix composites reinforced by short carbon fibers (CFs) attracted increasing attentions. To further improve mechanical properties and oxidation resistances, CFs were subjected to oxidation and acidification followed by sol-gel dip-coating to deposit ZrO2 on their surfaces. ZrO2-Cf/SiC composites were fabricated by joint hot compression molding and sintering, compared to Cf/SiC and SiC prepared by the same method. Microstructural analyses indicated that ZrO2 coatings were successfully deposited on CF surfaces, formed strong bonding and interfaces between CF and the matrix. Meanwhile, CFs were found uniformly distributed in SiC matrix with random orientations. Flexural curves of ZrO2-Cf/SiC and Cf/SiC revealed the presence of “false plasticity” regions after sharp drops, which were quite different from brittle flexural behavior of SiC ceramic. Compression strength of the three samples showed step-up growth. ZrO2-Cf/SiC exhibited the highest value, indicating the introduction of CFs and ZrO2 coatings do have great influence on mechanical performances. After heat treatment, ZrO2-Cf/SiC exhibited better oxidation resistance than Cf/SiC, with weight loss ratios estimated to ??3.76% and ??6.43%, respectively. These improved properties indicated that ZrO2-Cf/SiC would be excellent alternatives to other existence materials under ultra-high temperature environments. 相似文献
3.
阴,阳离子聚合物地层内凝胶化改善水驱效果的研究 总被引:9,自引:1,他引:8
研究了一杆阴离子聚合物(Ac530)和一种阳离子聚合物(Mb581)在水溶液中形成凝胶的条件和过程、凝胶化学结构、形态、稳定性和力学性能。在模拟地层的二维微观模型内观测了两种聚合物驱替渗流、相逼、形成凝胶、凝胶封堵大孔道的机理。在亲水填砂模型内测定了阴、阳离子聚合物凝胶体系降低渗透率的能力。 相似文献
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利用辐照的手段,来制备功能化的聚丙烯材料,在获得新功能的同时,不改变聚丙烯原有的优点,并综述了辐照技术在聚丙烯材料制备和改性中的研究及应用情况 相似文献
6.
Yueling Dai Peng Yang Lianzang Chen Kejian Liao 《Petroleum Science and Technology》2002,20(5):621-632
The boron heteroatom zeolite catalyst has been modified with silicon compound by Chemical Surface Deposition of Liquid-phase (CLD) technique and the catalytic property of the modified catalyst is studied. Meanwhile, the acidity of the modified zeolite catalysts is characterized through TPD and IR technique, and the fluid adsorption method is used to determine its pore structure. The relationship between the catalytic property of the zeolite catalyst and its pore structure, its acidity has been found. The results of toluene-ethylene alkylation reaction indicate that the selectivity of p-ethyltoluene on the modified zeolite catalyst is higher than that on the zeolite catalyst before silanizated, reaching 94.14%. 相似文献
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Kwang-Hee Lim 《Korean Journal of Chemical Engineering》2005,22(2):228-233
An experiment for five stages of a biofilter-run was performed to investigate the effect of hydrophilic ethanol and hydrophobic
toluene on the biodegradation of hydrophobic toluene and hydrophilic ethanol, respectively, when waste-air containing toluene
and ethanol was treated by a biofilter. Removal efficiencies of toluene and ethanol began to decrease when inlet load surpassed
90 g/m3/h and 100 g/m3/h consistent with maximum elimination capacities of toluene and ethanol, respectively. At the end of the biofilter-run, removal
efficiencies for toluene and ethanol were decreased and maintained at 65% and 40%, respectively. The concentration of toluene
at 1st sampling port was raised by factor of two in the 3rd stage of the biofilter run when the inlet load of ethanol co-feed
was increased by 1.5 times, while the process conditions of toluene were maintained the same as those of the 2nd stage of
biofilter-run. According to the result of Mohseni and Allen, it may be interpreted that removal efficiency of hydrophobic
toluene was affected by the presence of hydrophilic ethanol when high load of hydrophobic toluene was applied like that of
the 1st sampling port of the biofilter. However it was not the case when a low load of hydrophobic toluene was applied like
those of the 2nd, 3rd and 4th sampling ports since hydrophobicity of toluene is much less that of α-pinene. Thus, it may be
suggested that biodegradation of hydrophobic VOC was interfered by hydrophilic VOC dissolved in the biolayer and the degree
of interference was proportional to the inlet load of hydrophobic VOC as well as that of hydrophilic VOC and was inversely
proportional to the solubility of hydrophobic VOC. However, it was inferred that the existence of hydrophobic toluene from
waste-air can hardly inversely hinder the removal of hydrophilic ethanol in the biofilter when timeevolutions of hydrophilic
ethanol concentrations of this experiment were compared with those of the previous experiment of biofilter to treat waste-air
containing ethanol only. 相似文献
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