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101.
Zhaogang Teng Yandong Han Jun Li Feng Yan Wensheng Yang 《Microporous and mesoporous materials》2010,127(1-2):67-72
Hollow mesoporous silica spheres were synthesized by a sol–gel/emulsion (oil-in-water/ethanol) approach, in which cetyltrimethylammonium bromide (CTAB) surfactant was employed to stabilize and direct the hydrolysis of oil droplets of tetraethoxysilane (TEOS). The diameters of the hollow spheres can be tuned in the range from 210 to 720 nm by varying the ratio of ethanol-to-water and their shell thickness can be mediated by changing the concentration of CTAB used in the system. BET surface areas of the hollow silica spheres are determined to be in the range of 924–1766 m2 g?1 and their pore sizes are around 3.10 nm as determined by BJH method. 相似文献
102.
《能源学会志》2020,93(5):1809-1818
A novel tungsten-doped magnetic iron oxide catalyst was fabricated for selective catalytic reduction of NOx with NH3 (NH3-SCR), which was supported by carbon-included magnetic materials of Fe2O3–-H synthesized by the solution combustion followed by the oxidization of hydrogen peroxide. As a consequence, the thermal stability of γ-Fe2O3 crystallites located in the magnetic support is significantly enhanced. Meanwhile, the irreversible transformation of Fe2O3 crystallites from γ-phase to α-phase during the annealing process at high temperatures (i.e. 400 °C) is restrained to a large extent. In addition, the magnetic W/Fe2O3 catalyst presents a superb porous structure with higher BET surface area and pore volume due to the anti-sintering effect of tungsten doping on the magnetic Fe2O3. In this regard, the surface acidity as well as the molar ratio of the surface-adsorbed oxygen is substantially augmented, leading to a remarkable improvement of the redox ability of the active bulk species in the catalyst. It is worth mentioning that the promotions in thermal stability and redox ability is affected by the doping amount of tungsten in the catalyst, the molar ratio of glucose/urea/iron, and the ignition temperature for synthesizing the magnetic iron oxide support. The experiments revealed that with a doping amount of 7.5 wt%, a molar ratio of glucose/urea/iron of 5:20:8, and an ignition temperature of 400 °C, the NH3-SCR activity of the novel catalyst could be optimized. 相似文献
103.
《能源学会志》2020,93(5):1951-1959
The flow behavior of high-temperature ash (HTA) and low-temperature ash (LTA) of high calcium coal in the heating process was investigated systematically. By means of the heating stage microscope, the behavioral changes of samples were studied visually. The composition and mineral matters transformations of HTA and LTA samples were analyzed by X-ray fluorescence and X-ray diffraction. The results show that the original composition of HTA sample is different from that of LTA sample. In addition, the HTA and LTA samples experience the shrinkage, fusion and spreading processes in succession. However, the volume change of HTA sample is different from that of LTA sample. The volume of LTA sample shows a slow change at the temperature lower than 800 °C, while the volume of HTA sample is unchanged. In the temperature range of 800°C–1100 °C, the remarkable shrinkage of HTA and LTA samples are demonstrated. The formation of srebrodolskite and gehlenite attributes to this volume change. Moreover, the sharp shrinkage of HTA and LTA samples is indicated at 1100°C–1300 °C. This is caused by the formation of eutectics. Because of the diverse content and species of mineral matters in LTA sample, the volume change of LTA sample is more remarkable than that of HTA sample. The maximal shrinkages of LTA and HTA sample are 57% and 53%, respectively. 相似文献
104.
Zhang Zhiguo Zhang Mengxi Zhao Qihua Fang Lei Ma Shaokun Lv Xilin 《Bulletin of Engineering Geology and the Environment》2021,80(6):4651-4672
Bulletin of Engineering Geology and the Environment - Current scholars have made more efforts to investigate the deformation of landslide caused by tunnel excavation, but there are few studies on... 相似文献
105.
《Zeolites》1990,10(8):794-797
The catalytic activity of erionite and Y zeolites in the H form for amination of ethylene and their pattern of deactivation as the result of coke formation was evaluated at 365°C. H-Y undergoes linear deactivation (0.17% conversion loss per day) with extensive coking. Thermal regeneration is accomplished only at 600°C with partial loss of activity. In contrast, after an initial deactivation period (ca. 37% relative loss with 20 d), conversion and selectivity with H-erionite are almost stable. Catalyst activity is recovered without loss of crystallinity by thermal regeneration at 400°C. 相似文献
106.
107.
《International Journal of Hydrogen Energy》2020,45(8):5535-5542
This paper describes the reversible operation of a highly efficient microtubular solid oxide cell (SOC) with a nickelate-based oxygen electrode. The fuel cell was composed of a microtubular support of nickel and yttria stabilized zirconia (Ni-YSZ), an YSZ dense electrolyte, and a double oxygen electrode formed by a first composite layer of praseodymium nickelate (PNO) and gadolinium-doped ceria (CGO) and a second one of PNO. A good performance of the cell was obtained at temperatures up to 800 °C for both fuel cell (SOFC) and electrolysis (SOEC) operation modes, specially promising in electrolysis mode. The current density in SOEC mode at 800 °C is about −980 mA cm−2 at 1.2V with 50% steam. Current density versus voltage curves (j-V) present a linear behavior in the electrolysis mode, with a specific cell area resistance (ASR) of 0.32 Ω cm−2. Durability experiments were carried out switching the voltage from 0.7V to 1.2V. No apparent degradation was observed in fuel cell mode and SOEC mode up to a period of about 100 h. However, after this period especially in electrolysis mode there is an accumulated degradation associated to nickel coarsening, as confirmed by SEM and EIS experiments. Those results confirm that nickelate based oxygen electrodes are excellent candidates for reversible SOCs. 相似文献
108.
Inhibition of copper corrosion in 3.5 wt.% NaCl solution by domperidone was investigated by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The experimental results revealed that domperidone was an anodic inhibitor with a maximum achievable inhibition efficiency of 94.2%. The results of SEM and AFM studies further confirmed the inhibition action of domperidone. Quantum chemical calculation and the molecular dynamics (MD) simulation showed that the domperidone molecule could be adsorbed on copper surface through the imidazolidinone ring, benzene ring and N atom of hexaheterocyclic. Adsorption of domperidone was found to follow the Langmuir adsorption isotherm. 相似文献
109.
110.
本文介绍了国外部分天然气田井天然气中氡的浓度,四川主要天然气田天然气中氡含量监测结果,以及成都,重庆,自贡和泸州四城市居民用气室内氡污染状况。根据调查结果,提出了减轻氡危害的措施。 相似文献