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91.
研究目的:探究工业SO2排放与煤炭生产、消费存在必然的联系。研究方法:相关分析方法和改进的物理学重心模型。研究结果表明:(1)时序特征显示:西部煤炭生产、煤炭消费量和工业SO2排放量整体都呈现上升趋势,三者增长率均呈现多波峰“M”状波动。2)重心轨迹显示:工业SO2排放轨迹呈现为“倒L”型,煤炭生产和消费轨迹呈现为“J”型。(3)综合对比发现:煤炭生产从源头上影响工业SO2排放,煤炭消费从空间上影响工业SO2排放,为消减工业SO2排放改善生态环境,必须在优先减少煤炭消费增加清洁能源比重的同时,更应该关注对煤炭生产过程的管控。 相似文献
92.
John S. Mangum Lauren M. Garten David S. Ginley Brian P. Gorman 《Journal of the American Ceramic Society》2020,103(4):2899-2907
Selective synthesis of metastable polymorphs requires a fundamental understanding of the complex energy landscapes in which these phases form. Recently, the development of in situ high temperature and controlled atmosphere transmission electron microscopy has enabled the direct observation of nucleation, growth, and phase transformations with near atomic resolution. In this work, we directly observe the crystallization behavior of amorphous TiO2 thin films grown under different pulsed laser deposition conditions and quantify the mechanisms behind metastable crystalline polymorph stabilization. Films deposited at 10 mTorr chamber oxygen pressure crystallize into nanocrystalline Anatase at 325°C, whereas films deposited at 2 mTorr crystallize into significantly larger needle-like grains of Brookite and Anatase at 270°C. Increasing film deposition rate by a factor of 4 results in a 10× increase in the crystalline growth front velocity as well as a decrease in crystallization temperature from 270°C to 225°C. Engineering the amorphous precursor state through deposition conditions therefore provides routes to microstructure control and the accessibility of higher energy metastable phases. 相似文献
93.
Ruizi Li Jianfeng Huang Jiayin Li Liyun Cao Xiaoyi Li Guoxing Lu Aimin Yu 《国际能源研究杂志》2020,44(5):4026-4037
Sulfur doping has been regarded an energetic route to optimize the lithium storage properties of carbon-based electrode materials. In this work, sulfur-doped shaddock peel–derived hard carbon is successfully prepared by a KOH- and C2H5NS-assisted pyrolysis procedure. It is demonstrated that sulfur doping has strong effect on surface activation and graphitization enhancement, which results in the significant enhancement of the surface adsorption capacity and reaction kinetics of the hard carbon materials. When employed as a lithium ion batteries (LIBs) anode, the as-obtained hard carbon demonstrates excellent cycling and rate properties, presenting a great specific capacity of 738 mAhg−1 at 50 mAg−1 after 200 cycles, as well as 491 mAhg−1 at 200 mAg−1 after 300 cycles. Even at 1000 and 2000 mAg−1, the hard carbon provides a large rate capacity of 283 and 179 mAhg−1, respectively. Besides, it is revealed that the Li+ storage process is determined by the surface-induced pseudocapacitive process, whose capacitive proportion reach 60% at 0.5 mVs−1. This work suggests that the low cost and eco-friendly sulfur-doped shaddock peel–derived hard carbon is a very prospective LIB anode material. 相似文献
94.
Near- and short-wave IR emission spectra of printed cotton/nylon blend fabrics coated with inorganic compounds in order to tune their diffuse reflectance behavior to the ones with woodland and desert backgrounds are investigated. In this regard, cotton/nylon blend fabrics printed with a four-color digital pattern were used as the substrate, and different concentrations of zirconium and cerium dioxide (ZrO2 and CeO2) with and without citric acid as a cross-linker were loaded on these fabrics using the pad-dry-cure method. The diffuse reflectance of the coated fabrics with various concentrations of nanoparticles and a cross-linker was first measured by near-infrared (NIR) diffuse reflectance spectroscopy (DRS). Then, fabrics with an optimum concentration of nanoparticles and appropriate reflectivity profiles similar to woodland and desert were investigated by field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), washing, and rubbing fastness properties. In general, NIR and short-wave infrared (SWIR) reflectance of fabrics coated with ZrO2 and CeO2 nanoparticles in range of 1% to 1.5% (w/v [%]) was suitable for matching with different environments. According to the findings obtained from the durability test, it was concluded that the washing fastness of the treated fabrics with CeO2 nanoparticles was excellent in both environments. FE-SEM images of the treated fabrics containing ZrO2 and CeO2 indicated that the presence of nanoparticles on the surface of fabrics in woodland patterns was greater than the desert ones. However, the coated fabrics with CeO2 and citric acid in the woodland pattern have shown better dispersion with a mean particle size of 30 to 60 nm. 相似文献
95.
《International Journal of Hydrogen Energy》2019,44(16):8233-8242
To investigate the effect of support materials on catalytic performance in carbon dioxide reforming of coke oven gas, Ni-based catalysts supported on various metal oxides with various properties are prepared and evaluated. The support material affects the important properties related to the catalytic performance such as surface area, Ni dispersion, basicity, oxygen storage capacity, and interaction between Ni and support. Among the various catalysts on different metal oxides, Ni/MgOAl2O3 catalyst exhibits the highest CH4 conversion due to its high Ni dispersion, large surface area, and strong basicity. Hence, the Ni loading in the Ni/MgOAl2O3 catalyst is optimized. Ni loading performs the important roles to determine the Ni dispersion, the amount of Ni active sites, and basicity. 15 wt% Ni/MgOAl2O3 catalyst shows the highest catalytic activity even at a high gas hourly space velocity (GHSV) of 1,500,000 h−1, owing to the large amount of Ni active sites which related to Ni loading, Ni dispersion, and reduction degree. To confirm the stability of the 15 wt% Ni/MgOAl2O3 catalyst, catalytic reaction has been carried out for 50 h and noticeable catalytic deactivation is not observed for 50 h. 相似文献
96.
Feifei Xiao Xue Guo Jiao Li Haibin Sun Hua Zhang Weiwei Wang 《Ceramics International》2019,45(9):11856-11860
TiO2@carbon flexible fiber was prepared by combining electrostatic spinning technology and hydrothermal synthesis method. The XRD, SEM, TEM and Zeta potential techniques were used to characterize the phase, microstructure and surface charge properties of the samples. The growth mechanism of TiO2 nanoarray on carbon flexible fiber with different morphologies was studied, and the dye adsorption capacity of the samples was evaluated by methylene blue (MB) degradation effect. The results showed that proper doping amounts of TiO2 particles improved the flexibility and the hydrophilic property of carbon fiber significantly, which was conducive to the deposition and growth of TiO2 on the carbon fiber. With the increase of hydrothermal time, the TiO2 nanoarray grew denser gradually along the [110] crystal surface. The negative charge on the surface of carbon fiber increased, which was benefited to the removal of MB. The dye adsorption capacity of TiO2@carbon fiber was resulted from the synergistic effect of physical adsorption (carbon fiber) and photocatalysis (TiO2) process. 相似文献
97.
《International Journal of Hydrogen Energy》2022,47(44):19217-19236
In our previous work, phosphorylated chitosan was modified through polymer blending with poly(vinyl alcohol) (PVA) polymer to produce N-methylene phosphonic chitosan/poly(vinyl alcohol) (NMPC/PVA) composite membranes. The aim of this work is to further investigate the effects of a propylammonium nitrate (PAN) ionic liquid and/or silicon dioxide (SiO2) filler on the morphology and physical properties of NMPC/PVA composite membranes. The temperature-dependent ionic conductivity of the composite membranes with various ionic liquid and filler compositions was studied by varying the loading of PAN ionic liquid and SiO2-PAN filler in the range of 5–20 wt%. As the loading of PAN ionic liquid increased in the NMPC/PVA membrane matrix, the ionic conductivity value also increased with the highest value of 0.53 × 10?3 S cm?1 at 25 °C and increased to 1.54 × 10?3 S cm?1 at 100 °C with 20 wt% PAN. The NMPC/PVA-PAN (20 wt%) composite membrane also exhibited the highest water uptake and ion exchange capacity, with values of 60.5% and 0.60 mequiv g?1, respectively. In addition, in the single-cell performance test, the NMPC/PVA-PAN (20 wt%) composite membrane displayed a maximum power density, which was increased by approximately 14% compared to the NMPC/PVA composite membrane with 5 wt% SiO2-PAN. This work demonstrated that modified NMPC/PVA composite membranes with ionic liquid PAN and/or SiO2 filler showed enhanced performance compared with unmodified NMPC/PVA composite membranes for proton exchange membrane fuel cells. 相似文献
98.
以超临界二氧化碳(S-CO_2)干气密封为研究对象,建立变黏度变密度雷诺方程,通过构建物性数据库的方式对黏度及密度进行处理,并采用有限差分法对控制方程进行求解,得到端面压力分布,并计算开启力、泄漏量、摩擦扭矩和气膜刚度等稳态性能参数。结果表明:随着压力、转速的增大,开启力、泄漏量、摩擦扭矩、气膜刚度等参数均增大;随着槽坝比和槽深的增加,开启力、泄漏量和气膜刚度均增大,摩擦扭矩减小;随着槽数的增加,各稳态性能参数均减小;将槽坝比控制在0.5~1的范围内,有助于提高密封稳定性。 相似文献
99.
Titanium dioxide‐coated biochar composites as adsorptive and photocatalytic degradation materials for the removal of aqueous organic pollutants 下载免费PDF全文
100.
CO2 methanation over Ni and Rh based catalysts: Process optimization at moderate temperature 下载免费PDF全文
Muhammad Younas Sumathi Sethupathi Leong Loong Kong Abdul Rahman Mohamed 《国际能源研究杂志》2018,42(10):3289-3302
H2 was produced from aluminum/water reaction and reacted with CO2 over Ni and Rh based catalysts to optimize the process conditions for CO2 methanation at moderate temperature. Monometallic catalysts were prepared by incorporating Ni and Rh using nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and rhodium(III) chloride trihydrate (RhCl3·3H2O)as a precursor chemical. The preliminary study of the catalysts revealed higher activity and CH4 selectivity for Rh based catalyst compared to that of Ni based catalyst. Further, Rh based catalyst was investigated using response surface methodology (RSM) involving central composite design. The quadratic model was employed to correlate the effects of variable parameters including methanation temperature, %humidity, and catalyst weight with the %CO2 conversion, %CH4 selectivity, and CH4 production capacity. Analysis of variance revealed that methanation temperature and humidity play an important role in CO2 methanation. Higher response values of CO2 conversion (54.4%), CH4 selectivity (73.5%) and CH4 production capacity (8.4 μmol g?1 min?1) were noted at optimum conditions of 206.7°C of methanation temperature, 12.5% humidity and 100 mg of the catalyst. The results demonstrated the ability of Rh catalyst supported on palm shell activated carbon (PSAC) for CO2 methanation at low temperature and atmospheric pressure. 相似文献