排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
2.
Novel Co‐Mn‐O nanosheet catalyst for CO preferential oxidation toward hydrogen purification 下载免费PDF全文
Zhongkui Zhao Jinhan Lin Guiru Wang Turghun Muhammad 《American Institute of Chemical Engineers》2015,61(1):239-252
Co‐Mn‐O composite oxide nanosheet catalyst was successfully prepared using a facile urea‐assisted one‐step hydrothermal method in the absence of organic or organic templating reagent. Co‐Mn‐O nanosheet catalyst was optimized by varying hydrothermal process parameters such as molar ratio of Co‐Mn to urea, hydrothermal temperature, and hydrothermal time. Various characterization techniques including scanning electron microscopy, X‐ray diffraction, nitrogen adsorption, X‐ray photoelectron spectroscopy, Raman spectroscopy, and H2 temperature‐programmed reduction were used to reveal the relationship between catalyst nature and catalytic performance in CO preferential oxidation (CO PROX) in excess H2. The developed Co‐Mn‐O nanosheet catalyst have demonstrated much superior catalytic performance to Co‐Mn‐O nanoparticle, particularly in the low temperature range, and 100% CO conversion over the developed Co‐Mn‐O nanosheet can be achieved in temperature range of 50 to 150°C at 10,000 mL g?1 h?1 of gas hourly space velocity in the standard feed. Furthermore, the almost complete CO removal over Co‐Mn‐O nanosheet at 125°C of low temperature with 94.9% selectivity can be achieved even in the simulated reformed gas. The excellent catalytic performance is ascribed to nanosheet morphology, more surface Co3+, smaller average crystallite size, higher reducibility, and strong Co‐Mn interaction. Catalytic stability investigation indicates the developed nanostructured catalyst exhibits high catalytic stability for CO PROX reaction in simulated gas. The developed Co‐Mn‐O nanosheet catalyst can be a potential candidate for catalytic elimination of trace CO from H2‐rich gas for Proton exchange membrane fuel cell applications. © 2014 American Institute of Chemical Engineers AIChE J, 61: 239–252, 2015 相似文献
3.
4.
由于维吾尔文自身的特点,大多数已发表过的算法不能直接应用到视频中的这类文字。首先对视频帧的笔画滤波响应做全局阈值处理,然后利用维吾尔文在基线上横笔画居多的特征,通过水平投影找到基线位置,在基线上下方确定上下文本线。最后用垂直投影和启发式规则确定文本框。实验结果表明该算法对这类文字比较有效。 相似文献
5.
6.
7.
8.
维吾尔语动词体范畴的有限状态自动机的构建 总被引:1,自引:0,他引:1
维吾尔语动词的体范畴是维吾尔语动词语法范畴中极为复杂的范畴,也是维吾尔语信息处理中的难点问题之一,计算机对维吾尔语动词体范畴的处理是在对人称、时、否定等语法范畴处理之后才进行处理。但是难点就是体范畴重叠问题的解决。维吾尔语动词的体范畴词尾按照一定的规则连接在词干,这使得维吾尔语动词体范畴的重叠形式可用有限状态自动机形式化描述。因此它根据重叠规则构造从右向左的非确定自动机,之后把从右向左方向的自动机转换成从左向右的非确定自动机,最后把非确定自动机转换成确定自动机来实现维吾尔语动词体范畴的形式化描述。 相似文献
9.
以离子液体1-丁基-3-甲基咪唑氯盐([Bmim]Cl)为溶剂溶解纤维素(棉浆粕),在纤维素/[Bmim]Cl均相溶液中,以(NH4)2S2O8为引发剂、甲基丙烯酸丁酯(BMA)为单体、N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,采用自由基聚合法制备了纤维素/BMA接枝共聚物;采用FTIR,SEM,XRD,TG等手段对产物的结构和性能进行了表征;考察了聚合温度、时间以及(NH4)2S2O8、BMA、MBA的用量对接枝效果的影响。表征结果显示,纤维素/BMA接枝共聚物形态呈非晶态的粒状,结晶度明显降低、热稳定性相对提高。实验结果表明,纤维素/BMA接枝共聚物的最佳合成条件为:m(纤维素)∶m((NH4)2 S2 O8)∶m(BMA)∶m(MBA)=1.0∶0.1∶4.0∶0.1,65℃,2 h。在此条件下,接枝率可达94.5%,制备的纤维素/BMA接枝共聚物对水中二氯甲烷的吸收率达到了24.6 g/g。 相似文献
10.
笔者结合多年化工分离课程教学经验和分子印迹技术研究工作经历,提出以分子印迹分离过程为例讲授化工分离课程中的吸附过程。这样不仅可以有利于讲授吸附剂的选择性、吸附平衡等理论知识,还可以引入一种新型吸附分离方法尤其,还能用常用的实验室仪器设备为学生开设吸附分离实验课程,如测定吸附剂的性能及绘制透过曲线等,以达到提高教学效果为目的,值得尝试。 相似文献