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141.
A series of Pd/Co3O4 catalysts were prepared by Self-Propagating High-Temperature Synthesis (SHS) method in this study, and electric field was applied for catalytic combustion of lean methane over Pd/Co3O4 catalysts at low temperature. When electric field was applied, the catalytic combustion performance of Pd/Co3O4 catalysts was greatly improved, and the application of electric field could reduce the load of active element Pd to some extent while maintaining the same efficiency. Based on experimental tests and the analysis results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature-programmed reduction (H2-TPR) and in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS), the mechanism of catalytic oxidation of CH4 over Pd/Co3O4 catalysts in electric field was proposed. The catalytic combustion of CH4 occurs only when the temperature is higher than 250 °C normally, but when electric field was applied, the whole process of CH4 oxidation was promoted significantly and the reaction temperature was reduced. Electric field could promote the reduction of the support Co3O4 to release the lattice oxygen, resulting in the increase of PdOx and the surface chemisorbed oxygen, which could provide more active sites for the low-temperature oxidation of CH4. Furthermore, electric field could accelerate the dehydroxylation of CoOOH to further enhance the activity of the catalysts. 相似文献
142.
Polarization pattern provides additional information besides spectral signatures. It can be used in many applications, such as navigation, defect detection and object identification. A novel polarization camera composed of four synchronized cameras is proposed, and it can realize real-time polarization measurement. This study particularly concentrates on the geometric calibration of the system. The projection model is analyzed and the multi-camera calibration algorithm is proposed. Firstly, each camera is calibrated separately using planar patterns, and then the geometric calibration algorithms are performed. Due to the geometrical constraint, a global optimization method results in smaller estimation uncertainties. A mean rotation error of 0.025° and a mean translation error of 0.26mm are achieved after geometric calibration. The images are rectified to establish a correspondence among cameras and are combined to acquire the polarization measurement. The polarization pattern of the skylight is measured by the system and the results are consistent with the previous studies. 相似文献
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Cheng Xiaoling He Ling 《河北交通科技》2007,(4)
针对目前农村客运站建设与管理中存在的客运站点建设跟不上发展、客运市场经营主体混乱等问题,提出合理安排农村客运站点布局的原则以及"站所合一"、"三定四统一"等管理模式,以扭转农村客运市场的混乱局面。 相似文献
146.
Objective To study the expression of Nestin and glial fibrillary acidic protein (GFAP) in different period after spinal injury in adult rats. Methods Animal moels were created by artery clamp. Expression of Nestin and GFAP in different period ( 1,3,5days; 1-8 weeks) and different area( injury locus and its surrounding tissue ) after spinal injury were observed pathologicaly using immunofluorescence and LeicaQ5001W imaging processing system.Results There was expression of Nestin and GFAP in injured area 1 day after injury. The expression increased not only in in injured area but its sourrounding 3--7 days later and gradually got to peak value. As the time went on, expression of Nestin and GFAP dereased. Conclusion Spinal injury can induce the expression of Nestin. Nerve stem cell has response to spinal injury. There is positive correlation between expression of Nestin and hyperplasia of reactivity astrocyte. Nerve stem cell maybe invovled in the repair of central nervous system (CNS). 相似文献
147.
银杏叶提取物防治肝纤维化的实验研究 总被引:4,自引:2,他引:4
目的 探讨银杏叶提取物 (EGb)对慢性肝炎的防治作用及其机制。方法 SD大鼠随机分为正常组、模型组、EGb防治组和秋水仙碱组。用四氯化碳皮下注射法建立慢性肝损伤模型 ,分别用生理盐水或药物灌胃治疗。对比观察EGb对慢性肝损伤大鼠肝纤维化和脂质过氧化指标的影响 ,结合肝病理组织学及肝组织内Ⅰ、Ⅲ型胶原表达的变化加以探讨。结果 EGb防治组大鼠肝组织中PCⅢ、透明质酸、层黏连蛋白和CⅣ型胶原含量明显降低 ,血中过氧化物歧化酶、谷胱甘肽过氧化物酶活性明显升高 ,丙二醛含量明显降低 ,与模型组比较差异均有显著性意义 (P <0 .0 5或P <0 .0 1) ;形态学观察 ,EGb防治组大鼠肝组织损伤明显轻于模型对照组和秋水仙碱对照组 :HE染色显示肝组织炎症损伤减轻 ,VG染色显示肝组织纤维化程度明显减低 ,免疫组化染色显示肝组织中Ⅰ、Ⅲ型胶原表达明显减少。结论 EGb具有抑制脂质过氧化损伤 ,防治大鼠实验性肝纤维化的作用。 相似文献
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In this paper, we investigate the outage performance of a dual-hop amplify-and-forward(AF) multipleinput multiple-output(MIMO) relay network, considering beamforming transmission with outdated channel state information(CSI) and an arbitrary number of co-channel interferers at both the relay and the destination. The exact closed-form expression for the outage probability is derived, and the asymptotic behavior of the outage probability is also presented to provide further insights into the system performance. Our results show that the system suffers a diversity gain loss caused by the outdated CSI, and the interference only degrade the coding gain of the system. Moreover, increasing antennas can achieve more performance gains, however, the gains decrease as the delay of the CSI increases. 相似文献