Understanding heterogeneous catalysis on an atomic scale: a combined surface science and reactivity investigation for the dehydrogenation of ethylbenzene over iron oxide catalysts

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.     

顶驱电机方案研究

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。     

钢中氢分布检测技术进展

主要介绍了几种目前应用比较广泛的氢分布检测技术的原理及其在氢渗透和氢脆研究中的应用,包括三维原子探针(Atom Probe Tomography, APT)、扫描开尔文探针力显微镜(Scanning Kelvin Probe Force Microscopy, SKPFM)、二次离子质谱法(Secondary Ion Mass Spectroscopy, SIMS)和氢微印技术(Hydrogen microprintingtechnique,HMT),以及可用来检测氢浓度的热脱附质谱技术(Thermaldesorptionspectrometry,TDS)等。总结了几种检测技术的原理和特点,并简要介绍了它们在与H有关领域里的典型应用。其中,APT和SIMS是利用质谱法直接检测H,以获得H在材料中的分布;SKPFM是通过H引起的电位变化,来获得H的分布;HMT是通过置换反应,即H原子将Ag+置换为Ag原子,Ag原子沉积在试样表面的分布来表征H的分布;热脱附法则是通过恒定的升温速率下H脱附速率对不同陷阱的敏感性差异,来获得不同陷阱中的H浓度以及H与陷阱的相互作用。这几种检测技术的空间分辨率可达亚纳米、纳米、微米至数微米直至毫米级。另外,SKPFM还具有时间分辨的功能。这些技术在H检测方面的应用,使得研究者对H在材料中的微观分布与聚集状态有了直观地认识,进而对由氢引起的失效破坏(即氢致延迟断裂的微观机理)有了更深刻的理解。最后还介绍了目前比较常用的检测H浓度的方法。     

一个安全高效的学生综合管理系统

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。     

Discharge properties and chemical stability of SrZrO films

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.     

太赫兹技术及其应用研究的进展

过去十年来,太赫兹技术理论研究的蓬勃发展带动了太赫兹波应用领域的迅速扩大。本文概述了太赫兹波的产生、探测技术等基础研究的现状,重点介绍了近年来太赫兹波在物体成像、环境监测、军事和通信、医学和生物及其它几个应用领域的研究进展和最新研究成果。     

总溶解固体(TDS)对白泥脱硫浆液氧化影响实验

为改善白泥湿法烟气脱硫工!艺,研究白泥中总溶解固体(TDS)对白泥脱硫浆液氧化的影响,采用电感耦合等离子体质谱(ICP-MS)对浆液进行成分测定,研究浆液主要成分对浆液中亚硫酸钙氧化的影响,阐述了TDS对浆液氧化的影响机理,通过扫描电子显微镜(SEM)对实验产物和现场石膏样品进行分析.结果表明,高TDS对白泥脱硫浆液中亚硫酸钙氧化有明显的抑制作用,SEM结果表明,产物中生成簇状晶体,造成脱水困难.白泥脱硫石膏浆液中的可溶性盐,粒径在50~100μm,结晶效果较好,TDS抑制了白泥脱硫浆液的氧化,但是会提高溶液的过饱和度,使石膏晶体结晶良好.高TDS下Mn~(2+)的催化作用已不再明显.白泥脱硫副产品石膏脱水困难的原因之一是浆液中CaSO_3浓度过高,白泥应用于湿法烟气脱硫时应控制TDS,可保证白泥脱硫系统的正常运行,而不是只关注Cl~-.     

Alternating temporal dominance of sensations and liking scales during the intake of a full portion of an oral nutritional supplement

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.