Hydrogenation of commercial polystyrene over Pd/BaSO4 catalysts: Effect of carrier structure

A variety of barium sulfate （BaSO4） carriers with or without mesopore structure were synthesized via precipitation reaction in aqueous solution of barium hydroxide and sulfuric acid with ethylene glycol as a modifying agent, and then calcined at various temperatures. The obtained BaSO4 was used as catalyst carriers for polystyrene （PS） hydrogenation, and BaSO4 supported palladium （Pd） catalysts with Pd content of 5wt% were prepared by using impregnation method. N2 physisorption, transmission electron microscopy, X-ray diffraction and kinetics studies were used to investigate the effect of carrier structure on the dispersion and geometric location of active metal and their catalytic activities in PS hydrogenation. It was found that the pore structure of carrier played an important role in the dispersion and location of Pd grains. The activation energy values for all the Pd/BaSO4 catalysts were around 49.1 kJ/mol, while the pre-exponential factor for Pd/BSC-6H was much higher than others. The Pd/BSC-6H without mesopores had Pd grains deposited on the external surface of the carrier, and exhibited better activity than the mesoporous catalysts. It is indicated that the utilization of Pd/BSC-6H can reduce the pore diffusion of PS coils and enabled more active sites to participate in the PS hydrogenation.     

酒店实训对旅游管理毕业生择业观的影响研究——基于扎根理论的探索

在旅游业界,旅游管理毕业生"有业不就"的现象十分突出。文章通过对福建师范大学福清分校2011届、2012届、2013届毕业生的调查访谈,借助扎根理论的研究方法,分析归纳了酒店实训对旅游管理毕业生择业观的影响,并构建了产生此影响的关系结构模型。探究结果表明,酒店实训对旅游管理毕业生择业观的影响有两方面,其一是学生感知酒店管理模式的落差,其二是学生自身价值观的变化。     

高职院校人才培养与企业需求衔接的策略研究

高职院校人才培养与企业需求衔接策略研究是一项"系统工程",在实施"系统工程"时,必须以全面的观点考虑各个环节寻求两者无缝衔接的关键要素其策略,真正实现高职院校人才培养与企业需求无缝衔接。     

有效利用载体,推进高校“中国梦”主题教育

"中国梦"视阈下的大学生思想政治教育是一项系统工程。有效利用各种载体,推进"中国梦"主题教育,也是高校思想政治教育的题中之义。本文重点探讨了管理、文化、活动和传媒等几种类型载体在高校"中国梦"主题教育中的运用。     

地面数字电视单载波单频网关键技术

依据我国制定的地面数字电视标准组建某市的单载波单频网,介绍单载波单频网的规划设计方案,阐述了在单载波单频网建设中根据实际情况,科学合理地选择设备配置及解决方案,并对单载波单频网的关键技术进行深入的探讨。     

LTE-Advanced系统中下行物理层方面的载波聚合技术的研究

为了支持LTE-A达到100MHz的系统带宽的要求,3GPP提出了载波聚合技术。所谓载波聚合,就是LTE-A为了支持下行传输带宽超过20MHz聚合两个或者更多的成分载波(component carrier)。接收能力超过20MHz的LTE-A终端(User Equipment,UE)可以同时接收多个成员载波,而对LTE Rel.8的终端,也可以正常接收其中一个成员载波。文章重点研究了LTE-Advanced系统中下行物理层方面的载波聚合技术。     

图书载体材料与阅读方式的变迁

图书载体材料由天然材料、人工合成植物纤维材料演变至今,随着信息技术、数字技术和计算机技术的不断发展,在文献信息储存领域出现了许多新型的文字载体,跨媒体出版已成为不可阻挡的趋势.     

A study of spectrin and lipid peroxidation of red blood cell membrane in thalassaemia carrier

The aim of the present work is to understand the lipid peroxidation of RBC membrane and the spectrin protein content of RBC membrane cytoskeleton of thalassaemic carrier state (trait) of β and hemoglobin E variant (HbE). We have measured the hemoglobin (Hb), malondialdehyde (MDA) and spectrin content of RBC membrane of thalassaemic carrier. The spectrin content (α and β band) of both β and HbE carrier was not changed than normal individuals. However, lipid peroxidation of RBC membrane was significantly increased in both β and HbE trait, and Hb level was also decreased in thalassaemic carrier. It may be assumed that oxidative damage by excess lipid peroxidation may have no role on irreversible membrane damage in β thalassaemia and HbE thalassaemia carrier.     

"砧"与中国古代捣衣诗及思妇诗

"砧"是中国古代一种简单的捣衣工具,由捣衣活动而兴起的捣衣诗基本上都是思妇诗,二者表现为二位一体的关系,形成"捣衣-思妇"诗."砧"是这种"捣衣--思妇"诗中的主体意象,从文本接受角度看,这一意象既有文化价值又有文学艺术价值.     

地方课程--少数民族地区实施多元文化教育的载体

多元文化教育是地方课程特征之一，在我国少数民族地区基础教育阶段，可以把地方课程作为对少数民族学生实施多元文化教育的载体。将多元文化教育理论与地方课程理论相结合不失为地方课程理论研究的新视角。