Roles of interaction between components in CZZA/HZSM-5 catalyst for dimethyl ether synthesis via CO2 hydrogenation

The roles of interaction between two catalyst components in CuO–ZnO–ZrO₂–Al₂O₃ (CZZA)/HZSM-5 bifunctional catalyst for dimethyl ether (DME) synthesis via carbon dioxide hydrogenation were investigated. It was found that CZZA catalyst showed excellent stability during methanol (MeOH) synthesis for 100 h, while there was a severe loss of catalytic activity in the bifunctional catalyst for DME synthesis. Hence, the effects of different degrees of intimacy of two catalyst components were studied for DME synthesis, including mixed and separated modes. For the mixed mode, the particle size of catalysts and the amount of reaction intermediates were proven to influence the catalyst deactivation. For the separated mode, the catalysts showed rapid deactivation within a short time. Various characterizations indicated that the remarkable deactivation of separated mode was mainly caused by the decrease of copper active centers (e.g., sintering and oxidation) and blockage of acid sites via increased coke deposition on HZSM-5.     

工程设计演示文档动态性表述的探讨

在工程投标、方案论证、学术交流中 ,可利用多媒体演示软件制作各类文档。为了充分表达制作人员的思想 ,达到预期目的 ,可采用丰富多彩的动态性表现手法 ,使演示产生很好的效果 ,令听众和观众欣然接受。为此 ,对工程设计演示文档的动态性表述进行了探讨 ,以便能更充分地发挥多媒体演示软件的作用     

基于三维场景出图的拼接制作2.5维地图算法

针对目前2.5维电子地图的制作与其三维虚拟场景相对独立,且不易更新维护的问题,提出了对三维场景进行图片输出并拼接实现2.5维地图制作的算法。首先设定摄像机长宽值作为最小出图单位,在指定范围内,使用最小出图单位以任意水平角度和俯仰角度输出三维虚拟场景效果图,并记录相关空间信息。然后根据图片左上角点坐标值对所输出图片进行无缝拼接。实验结果表明,该方法在保证地图空间实体表现能力的同时,能够快速替换图中更新区域,提高2.5维地图制作效率。     

多级半色调技术在电纸书显示优化中的应用

针对电纸书显示屏灰度等级不足的问题,提出了利用半色调图像处理技术的改进算法实现电纸书显示优化的方法.在阐述半色调技术与电子纸特点的基础上,介绍了抖动算法和误差扩散算法,通过对这两种算法进行改进提高电纸书显示的灰度级数及视觉效果.其中重点对误差扩散算法中的阈值、滤波器及扫描方式的设定进行设计,并提出一种基于误差动态检测的新的改进算法,能有效提高图像灰度级数,改善电纸书的图像显示质量.最后在电纸书系统平台上实现仿真,通过质量评价参数客观地评测了各种算法.     

A Comprehensive Website Meets the Serials Librarian's Back Issue Needs

Abstract

The author describes USBE's Website, which meets virtually every back issue need of the serials librarian. An online catalog of over 17,000 scholarly journal title holdings, order page, membership application, and a fee-free out-of-print book search service are some of the features of the USBE site. The USBE Web pages also include instructions on how to donate surplus periodicals to the nonprofit organization, as well as special offers and other news pertinent to serials librarians. Includes interview comments by USBE President, John Zubal and USBE Operations Manager, Jean Marie Zubal.     

鄱阳湖水利枢纽工程关键技术研究

本文针对鄱阳湖水利枢纽工程修建后将发挥的作用和可能产生的影响,采用现场调研、实测资料分析和数学模型计算等研究手段,从鄱阳湖流域水资源演变趋势及开发利用状况,三峡水库运用对长江中下游河道冲淤变化及江湖关系的影响,枢纽工程对水资源、防洪、湖区水环境和鱼类的影响,枢纽工程合适的下闸蓄水时期和蓄水位,工程闸门型式及鱼道建设等方面进行了研究,试图为鄱阳湖水利枢纽工程项目立项和规划设计提供科技支撑。     

制造网格任务分解规则、方法及应用研究

为了实现制造网格的资源共享与协同工作,制造网格任务需要拆分成若干设计、制造、装配等多种类型的子任务（活动）的形式,以便于多个服务节点、多方面人员进行协作完成。分析了制造网格任务分解的基本特点,提出了一种基于QoS的制造网格任务分解规则,在此基础上,提出了制造网格任务分解的基本方法和步骤,最后,通过应用实例说明了该规则和方法的有效性和可行性。     

整合Blackboard的资源管理平台的开发研究

目前普通高等教育和基础教育都建有比较完善的数字化教学资源和相应的资源管理平台,但可与Blackboard在线教学系统整合的资源平台还很少见。为此,在立足本校实际情况,依照LOM元数据规范,设计数字化教学资源管理平台的系统框架与功能。该平台不仅具有资源管理功能,并能与Blackboard在线教学系统和图书资源目录实现整合。     

敏感图片自动检测系统的研究

设计并实现了一个敏感图片自动识别系统。该系统首先利用肤色模型从敏感图片中检测出肤色区域,再从图片肤色区域中,提取大量经验特征表示图像内容,然后采用Haar特征算法设计一个检测敏感部位对象的分类器,最后通过敏感部位的几何特征逐级识别正常图片与敏感图片。该检测系统具有良好的系统性能。     

The educational electronic book as a tool for supporting children’s emergent literacy in low versus middle SES groups

The effects of an educational electronic book (e-book) on 149 five- to six-year-old kindergarteners’ emergent literacy levels were researched in two SES groups: low (LSES) (79 children) vs. middle (MSES) (70 children). In each SES group, children were randomly assigned to four groups. Three groups were assigned to work individually in one of three e-book activity modes: “Read story only”, “Read with dictionary”, or “Read and play” during three similar activity sessions and the fourth group served as a control which received the regular program of the kindergarten. Pre- and post-intervention emergent literacy measures included word meaning, word recognition, and phonological awareness. Results show that word meaning of children from both middle and low SES improved following the educational e-book activity, regardless of mode. Second, LSES children’s emergent literacy levels showed relatively greater improvement rates than did those of the MSES children. Third, children in the “Read with dictionary” and “Read and play” activity modes showed more improvement in their emergent literacy levels than did those in the “Read story only” mode. Implications for future research and for education are discussed.