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71.
Microbially influenced corrosion (MIC) on internal pipeline surfaces has become a severe problem during the water injection process in secondary oil recovery. The formation of a biofilm, normally dominated by sulfate‐reducing bacteria (SRB), is believed to be the critical step of the MIC process. A continuously fed biofilm simulating the water injection process was operated to investigate the influence of biofilm development on MIC behavior in the early phase of corrosion development. The development of the corrosion product film and biofilm was monitored for 5 months with electrochemical impedance spectroscopy, linear polarization resistance, scanning electron microscopy, 3D optical profiling, and direct weight measurement. MIC development was found to comprise three phases: initialization, transition, and stabilization. The initialization phase involved the formation of the corrosion product layer and the initial attachment of the sessile microbes on metal surface. In the transition phase, the MIC process gradually shifted from charge‐transfer‐controlled reaction to diffusion‐controlled reaction. The stabilization phase featured mature and compact biofilm on the metal surface, and the general corrosion rate (CR) decreased due to the diffusional effect, while the pitting CR was enhanced at a lower carbon source level, which supported the mechanism of direct electron uptake from the metal surface by SRB. 相似文献
72.
Multimedia Tools and Applications - Copy-move forgery detection can generally be divided into two categories: block-based or keypoint-based methods. However, the existing block-based methods are... 相似文献
73.
Peng Shen Fengqing Zhang Lingxu Wang Xiaodong Guo Xuefeng Zhao Huiying Liu Qingbo Tian Suhua Fan 《International Journal of Applied Ceramic Technology》2020,17(3):1392-1399
BiFe1−xZnxO3 (x = 0, 0.5, 1, 1.5, 2 mol%) (BFZO) films were prepared on ITO/glass substrates by a sol-gel method. The effects of different Zn contents on the structures and electrical properties of the BFZO films were investigated. From X-ray diffraction (XRD), microstructure and X-ray spectroscopy (XPS) results, the BFZO films with a Zn content of 1 mol% showed a better crystal structure and grain development, and the Fe2+ and oxygen vacancy concentrations in this sample were the lowest among all the evaluated BFZO films. The P-E hysteresis loop indicated that the BFZO films with 1 mol% Zn had the highest remanent polarization (2Pr), which was 82.4 μC/cm2, along with a coercive field (2Ec) of 887 kV/cm at the tested electric field of 857 kV/cm. The BFZO film with 1 mol% Zn had the lowest leakage current density, which was 3.54 × 10−7 A/cm2 at the tested electric field of 200 kV/cm. Both at high and low electric fields, the space charge-limited current (SCLC) conduction mechanism was the main leakage mechanism. When the test frequency was 105 Hz, the dielectric constant was 133, and the dissipation factor was 0.015. 相似文献
74.
为了提高基于镧锶锰氧化物(LaxSr1-xMnO3,LSM)阴极的中温固体氧化物燃料电池(Solid Oxide Fuel Cell,SOFC)的电化学性能,文章利用CuO清扫Ce0.85Sm0.15O2-δ(SDC)晶界的SiO2杂质以提高SDC的离子电导率,制备了复合电解质材料SDC-CuO,并将SDC-CuO和LSM结合成复合阴极材料,随后分别制备了以LSM和LSM/SDC-CuO作为阴极的SOFC,并研究了这两种SOFC的电化学性能。研究结果表明:在开路电压和工作温度为800℃的条件下,LSM/SDC-CuO基阴极的SOFC的极化电阻为0.14Ω·cm2,明显低于LSM基阴极SOFC的极化电阻(0.36Ω·cm2);LSM/SDC-CuO基阴极的SOFC的最大输出功率密度为237 mW/cm2,显著高于LSM基阴极的SOFC的最大输出功率密度(132 mW/cm2)。 相似文献
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78.
采用基于计算流体力学方法的全尺度数值模拟计算,建立了适用于潮流能水轮机模拟的剪切来流环境,通过数值计算结果,对潮流能水轮机随时间变化的宏观力和流场特征进行了系统分析,探索水轮机在复杂工况下的水动力特性规律。结果表明,水轮机整个叶轮的总体平均受力在剪切流工况中未受到明显影响; 单个叶片的瞬态轴向力系数和瞬态轴向扭矩系数在旋转周期内出现了明显的周期性变化,且周期性变化幅值随转速增大而增大; 非定常的瞬时轴向扭矩和力的周期性振荡容易引起单个叶片的结构性振动,可能对水轮机的机械结构造成影响。 相似文献
79.
Jialong Tian M. Babar Shahzad Wei Wang Lichang Yin Zhouhua Jiang Ke Yang 《材料科学技术学报》2018,34(9):1671-1675
The effect of Co addition on the formation of Ni-Ti clusters in maraging stainless steel was studied by three dimensional atom probe (3DAP) and first-principles calculation. The cluster analysis based on the maximum separation approach showed an increase in size but a decrease in density of Ni-Ti clusters with increasing the Co content. The first-principles calculation indicated weaker Co-Ni (Co-Ti) interactions than Co-Ti (Fe-Ti) interactions, which should be the essential reason for the change of distribution characteristics of Ni-Ti clusters in bcc Fe caused by Co addition. 相似文献
80.
Tian Li 《China City Planning Review》2018,(3)
As a SPURS fellow, my one-year study at MIT had a great impact on my career in urban planning and education. I gained knowledge regarding planning systems in the USA, and my view on planning was changed and expanded. This paper reviews my experience as a SPURS fellow at MIT, and concludes with an analysis of planning education in China from the perspective of a SPURS fellow. 相似文献