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991.
以十二烷基苯磺酸钠(SDBS)作为发泡剂,凝胶注模结合发泡法制备多孔氧化铝陶瓷.研究了发泡剂SDBS的添加量对多孔氧化铝陶瓷的气孔率、孔径尺寸及气孔分布和抗弯强度的影响.研究结果表明,在一定范围内随发泡剂SDBS添加量的增加,总气孔率和闭气孔率会有明显的上升趋势,孔径尺寸差异逐渐变小,气孔分布的均匀性逐渐变好.当SDBS的添加量超过1.0wt% 后,气孔率虽然无明显变化,但是样品孔径尺寸及气孔分布的均匀性均变差,样品的抗弯强度随着SDBS用量的增加有明显降低的趋势.当SDBS的添加量为1.0wt% 时,可以制备出闭气孔率为49%,抗弯强度为35 MPa,孔径尺寸及气孔分布均匀的多孔氧化铝陶瓷. 相似文献
992.
本文研究了不同的热焖压力和时间对钢渣活性的影响和钢渣的不同掺量对水泥性能的影响.热焖工艺主要改善的是钢渣的膨胀性,熟料的7 d膨胀率为0.034%,未热焖的钢渣掺入15%和35%时膨胀率分别增加155.9%和311.8%,而1 MPa 1 h热焖后,相比于未热焖的情况,钢渣掺入15%和35%时分别降低77.0%、89.3%,钢渣掺量25%时,其3 d、7 d、28 d 抗压强度分别增加8. 0 MPa、3.6 MPa、2.7 Mpa,分别提高21.1% 、11. 3% 、6. 1%. 相似文献
993.
Maria Portarapillo Giuseppina Luciani Roberto Sanchirico Almerinda Di Benedetto 《American Institute of Chemical Engineers》2020,66(8):e16256
Understanding flame propagation mechanism and thermal behavior of flammable dusts is of crucial importance, since they strongly affect the flammability and explosion parameters. In a previous work, we found that the volatile point of anthraquinone/nicotinic acid mixtures can be lower than the one of the pure dusts, suggesting a synergistic effect. In this work, thermogravimetric and differential scanning calorimetry analyses of anthraquinone/niacin mixtures were carried out both in open and closed cup, to explain the observed synergistic behavior. FTIR analysis on solid residue and evolved gaseous species showed that the mixtures change compositions during the thermal treatment, without undergoing any chemical transformation. The thermal behavior of dust mixtures reveals the presence of a eutectic point, resulting in a volatiles production at lower temperature and accelerating the flame propagation. 相似文献
994.
Di Suo Zhen Fang Yang-Yang Yu Yang-Chun Yong 《American Institute of Chemical Engineers》2020,66(4):e16897
Microbial electrocatalysis systems (MES) provide a cutting-edge solution to global problems associated with the environment and energy, but practical applications are hindered by the expensive electrode materials. Although stainless steel (SS) has been proposed as a promising inexpensive candidate, poor cell/SS interaction results in a low performance for MES. Here, a new synthetic biology approach was established for reinforcing the cell/SS interaction. Hybridized curli nanofibers fused with a metal-binding domain were heterogeneously expressed onto the cell surface, which realized efficient cell binding with the SS electrode. Consequently, it enabled a ~420-fold improvement of the anodic power output and a substantial enhancement of the cathodic Coulombic efficiency (from 0.6 to 4% to over 80%) with an SS electrode. This work demonstrates low-cost MES with an SS electrode and introduces a new avenue to engineer the cell/electrode interaction, which is promising for future practical applications of MES. 相似文献
995.
Zhanhui Peng Di Wu Pengfei Liang Xiaobin Zhou Jitong Wang Jie Zhu Xiaolian Chao Zupei Yang 《Journal of the American Ceramic Society》2020,103(2):1230-1240
Dielectric materials with ultrahigh permittivity are attracting attention due to the increasing demand for these types of materials for microelectronics and energy storage applications. In this work, we successfully synthesized Zn-doped CdCu3Ti4O12 (CdCTO) ceramics with low dielectric loss and large permittivity via an ordinary mixed-oxide technique. Remarkably, at a Zn doping level of 0.10, a CdCu2.9Zn0.1Ti4O12 ceramic exhibited both decreased dielectric loss tangent of ~0.058 and large dielectric permittivity > 4.0 × 104, as well as a good frequency stability over a wide frequency range from 40 Hz to 106 Hz. The high dielectric performance was attributed to the enhanced grain boundary resistance and internal barrier layer capacitor (IBLC) effect due to the fine and uniform grains that formed upon Zn doping. The findings reported in this work provide valuable insights into how to simultaneously realize a low dielectric loss and high permittivity in CdCTO and other related dielectric ceramics. 相似文献
996.
Linan He Caina Luan Di Wang Yong Le Xianjin Feng Jin Ma 《Journal of the American Ceramic Society》2020,103(4):2555-2561
Zinc stannate (Zn2SnO4) films were deposited on MgO (100) substrates by pulsed laser deposition, and Zn2SnO4 monocrystalline films were obtained by postannealing process. The structures, surface morphologies, and optical properties of the Zn2SnO4 films annealed at different temperatures were investigated in detail. Crystal structure analyses showed that the film annealed at 800°C was single crystal Zn2SnO4 with an inverse-spinel structure. The heteroepitaxial mechanism was further clarified by a schematic diagram, and the epitaxial relationships between the film and substrate were Zn2SnO4 (400) || MgO (200) with Zn2SnO4 [001] || MgO [001]. The obtained Zn2SnO4 films exhibited excellent transparency. The optical band gap of the 800°C-annealed Zn2SnO4 film was about 3.97 eV. The extinction coefficients and refractive indexes of the Zn2SnO4 films annealed at different temperatures as a function of wavelength were analyzed in detail. 相似文献
997.
Zhangyi Huang Mao Zhou Zhangkai Cao Zhe Tang Yutong Zhang Junjing Duan Jianqi Qi Xiaofeng Guo Tiecheng Lu Di Wu 《Journal of the American Ceramic Society》2020,103(5):3425-3435
Gd2Zr2O7 ceramics with different grain sizes ranging from nanoscale to submicron scale (91, 204, and 634 nm) were irradiated at room temperature using 190 keV He ions with doses ranging from 5 × 1016 to 5 × 1017 ions/cm2. We fully characterized the pre- and post-irradiation samples using grazing-incidence X-ray diffraction (GIXRD), scanning electron microscope (SEM), and atomic force microscope (AFM) as the grain size and degree of irradiation vary. The results suggested that all three Gd2Zr2O7 samples demonstrate outstanding radiation tolerance to displacement damage by retaining their crystallinity after irradiation at 5 × 1017 ions/cm2. which is equal to 16 displacement per atom (dpa) at peak positions. Although lattice expansion was observed at a He irradiation at 5 × 1016 ions/cm2 and beyond, the lattice remained stable for the nanograin ceramic, while the degree of distortion for the sample with the largest grain size (634 nm) continuously increased. Moreover, a delayed He bubble evolution process was seen for the nanograin ceramic, which did not appear for the submicron-grained sample. Interestingly, the grain size-dependent surface blistering was also found to be a function of ion fluence. After He irradiation at 5 × 1017 ions/cm2 the AFM root-mean-square(RMS) roughness variation for Gd2Zr2O7 ceramics of 91, 204, and 634 nm were 4.8, 7.0, and 11.1 nm, respectively. 相似文献
998.
Camilla Costa Renzo Di Felice Paolo Moretti Maddalena Oliva Rouzbeh Ramezani 《加拿大化工杂志》2020,98(12):2516-2529
This work is a companion to a previous article, Part I, published in The Canadian Journal of Chemical Engineering, dealing with CO2 absorption in aqueous solutions containing a single aminic reagent (specifically methyldiethanolamine (MDEA) or piperazine (PZ)). In this second part, different PZ/MDEA mixtures are experimentally studied and their performances are compared with that of the single reagents. It is indeed well known that small quantities of PZ added to MDEA aqueous solutions are sufficient to obtain a significant improvement in the kinetics of the process. PZ is considered an activator or promoter for MDEA, but the mechanism of this synergy has still not been clearly demonstrated. The aim of this study is an attempt to understand how PZ and MDEA can interact by experimentally analyzing this beneficial mutual effect and by explaining it with the help of a suitable yet not complex model. We believe that the involved chemistry is not more complex than that reported in Part I for the single reagents. According to our findings, it is MDEA that enhances the action of PZ, as opposed to what many authors claim. Moreover, our results seem to rule out the existence of any PZ shuttle effect. 相似文献
999.
Zhanbin Wang Jiahao Liu Houchao Shan Guozhen Li Ze Wang Zhihao Si Di Cai Peiyong Qin 《应用聚合物科学杂志》2020,137(42):49308
In this study, Schiff base network (SNW)-1 nanoparticles with high hydrophilicity and large specific surface area were used to prepare polyvinyl alcohol (PVA)-based mixed matrix membranes (MMMs), which were evaluated for ethanol dehydration. Because of the low difference of density between SNW-1 and PVA, the as-prepared nanoparticles can be uniformly distributed into the PVA active layer. The effects of SNW-1 loading, feed temperature, and water concentration on pervaporation (PV) performance were further studied. The results showed the MMM with 10 wt% of SNW-1 loading exhibited a separation factor of 1,501 and a permeation flux of 187 g m−2 h−1 for feeding 95 wt% ethanol/water binary solution at 75°C. Overall, the SNW-1/PVA MMMs showed great prospect in ethanol dehydration via PV. 相似文献
1000.
分别采用硫酸、盐酸和硝酸对尿素热解得到的体相块状石墨相氮化碳(g-C_3N_4)进行质子化改性,超声剥离得到氮化碳纳米片,考察3种质子化氮化碳纳米片对亚甲基蓝染料的光催化降解性能,利用XRD、FT-IR、SEM、BET、UV-DRS、UV-VIS等对其结构、形貌、比表面积、禁带宽度进行分析。结果表明,硫酸改性后的g-C_3N_4比表面积最大(60. 9 m~2·g~(-1)),亚甲基蓝降解效果最好,降解率为46. 7%,相比于体相块状g-C_3N_4的29. 2%提高了17. 5个百分点。以硫酸质子化改性的g-C_3N_4为前驱体,采用搅拌法制备得到质子化g-C_3N_4/石墨烯复合材料,其光催化降解亚甲基蓝的降解率为81. 7%,较硫酸质子化g-C_3N_4提高了35. 0个百分点。 相似文献