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In order to study the dehydrogenation of ethylbenzene to styrene, epitaxial iron oxide model catalyst films with Fe3O4(111), -Fe2O3(0001) and KFe
x
O
y
(111) stoichiometry were prepared in single crystal quality on Pt(111). They were investigated using surface science techniques before and after atmospheric pressure reaction experiments in a newly designed single crystal flow reactor. As expected from low-pressure measurements, Fe3O4(111) is catalytically inactive. The catalytic activity of -Fe2O3(0001) starts after an activation period of about 45 min. After that, the surface is essentially clean but shows a high concentration of defects. On the potassium-promoted films, however, the activation period is much longer, the activity then is higher and the surface gets covered completely with carbon and oxygen during reaction. This indicates a different reaction pathway on the promoted films with a carbon–oxygen species as catalytically active species. 相似文献
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阐述了顶驱电机的类型与特点,分析了顶驱钻井系统的钻进工况,并结合开关磁阻电机技术对顶驱电机方案进行了研究。 相似文献
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为了解决学生管理系统的安全性和效率问题,分析了已有系统的不足,提出了一个安全高效的学生综合管理系统的解决方案。该方案利用C/S结构安全中间件,进行SQL Server 2000安全设置弥补TDS(TabularData Stream)协议漏洞、与已有数据库系统数据共享等方法,保证了管理系统的可用性和有效性,克服了已有系统存在的安全性不高、效率低下的不足。基于PowerBuilder的前端和SQL SERVER 2000的后台的系统运行结果表明,该方案可行有效。 相似文献
5.
Yusuke Fukui Yosuke Honda Yasuhiro Yamauchi Michiko Okafuji Masahiro Sakai Mikihiko Nishitani Yusuke Takata 《Journal of the Society for Information Display》2010,18(12):1090-1094
Abstract— MgO thin film is currently used as a surface protective layer for dielectric materials because MgO has a high resistance during ion sputtering and exhibits effective secondary electron emission. The secondary‐electron‐emission coefficient γ of MgO is high for Ne ions; however, it is low for Xe ions. The Xe content of the discharge gas of PDPs needs to be raised in order to increase the luminous efficiency. Thus, the development of high‐γ materials replacing MgO is required. The discharge properties and chemical surface stability of SrO containing Zr (SrZrO) as the candidate high‐γ protective layer for noble PDPs have been characterized. SrZrO films have superior chemical stability, especially the resistance to carbonation because of the existence of a few adsorption sites due to their amorphous structure. The firing voltage is 60 V lower than that of MgO films for a discharge gas of Ne/Xe = 85/15 at 60 kPa. 相似文献
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Measurement of liking with consumers is often performed on a single sip or mouthful of the product and results in a single liking score that does not necessarily reflect the liking over consumption of a whole product. A dynamic approach could provide this type of information. Thus, obtaining reasons why the liking score is changing over consumption could help to gain insights for product improvement. Recently, Thomas, Visalli, Cordelle, and Schlich (2015) suggested collecting with the same consumers liking scores dynamically and Temporal Dominance of Sensations (TDS) during mono-intakes of flavored cheeses, in two independent sessions. This new type of sensory data has been analysed at individual level to identify “temporal drivers of liking” for each product.The present paper further develops this method consisting of collecting TDS and dynamic liking data in the same session and during the consumption of the full portion of a product. The products used to experiment this new method were two commercial oral nutritional supplements (ONS) assessed by 65 consumers over two lab sessions separated by one week.The protocol consisted of a TDS evaluation of 5 flavor, 2 texture and 3 taste sensations during each sip, immediately followed by a liking scale. This protocol was repeated over sips. This method, named “Alternated Temporal Drivers of Liking” (A-TDL), required that consumers record liking changes and do TDS over sips during food consumption. Results showed that one of the two ONS was more liked than the other and consumed in a larger volume resulting in a higher energy intake. In contrast, the other product resulted in a stronger thirst and presented more negative temporal drivers of liking (dry, metallic, filming) over the consecutive sips. 相似文献
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有机-无机联合矿井突水水源判别方法 总被引:7,自引:0,他引:7
溶解性有机质(Dissolved Organic Matter,DOM)在随地下水运移过程中,不同含水层水中DOM含量、类别、荧光强度等均存在较明显差异,因此结合无机水化学,开展了有机-无机联合的矿井突水水源判别方法研究,结果表明:地下水中无机组分浓度分布具有垂向分带性,利用pH、矿化度(TDS),HCO3,SO4等无机指标,可以判别浅部含水层和深部含水层水化学特征差异; DOM进入含水层后发生氧化还原反应强烈,其浓度(TOC含量和UV254)变化快、差异大,可以识别地表水与第四系水的水化学特征;第四系与白垩系含水层,以及覆岩破坏范围内的细分含水层,水中无机组分和有机组分含量非常接近,而荧光指纹技术灵敏度高,可以根据3DEEM光谱图分析DOM类型和荧光峰强度等差异,区分相邻含水层的水化学特征差异。陷落柱等地质异常体作为特殊的地质环境体,其内部水体中DOM相对丰富,其DOM含量和荧光指纹特征与奥灰水差异显著。将有机-无机联合开展不同含水层水化学特征分析,能够很好地区分不同水源,为矿井突水事故发生时快速判别水源提供科学依据。 相似文献
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本文通过对TDS3000B系列数字示波器几类常见故障现象的总结归纳,在系统研究仪器自身结构特点和电路组成的基础上,结合日常维修工作实践分析了各类故障具体成因,综合运用比对测量、电路功能性分割、在线追踪等故障测量分析方法,分析测量数据,逆向绘制出仪器局部电路原理图,研究并形成了具有针对性的故障诊断定位方法以及维修关键技术。 相似文献
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