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41.
甲醇生产技术新进展与市场分析及预测   总被引:1,自引:0,他引:1  
概述了国内外甲醇主要生产技术新进展,对国内外甲醇市场供需情况进行了分析预测,针对影响国内甲醇业未来的因素提出了发展建议。  相似文献   
42.
Dieser Beitrag geht auf die Planung und die Bauausführung des Bürohochhauses des “Palais Quartier” in der Innenstadt von Frankfurt am Main ein. Beschrieben werden die Konstruktion und der Bauablauf des 5‐geschossigen Kellerkastens und der Abfangung eines 12 m × 15 m großen Gebäudeteils sowie die Planung, im Speziellen die Verformungsuntersuchung für die Stahlbetonstützen. Office Tower in the Palais Quartier — a special construction project in the city of Frankfurt/Main. This article covers the design and the construction of the office tower of the ”Palais Quartier“ in the city center of Frankfurt am Main. In the following, the structural design and the construction work of the 5 basement levels and the overhanging part of the building with dimensions 12 m × 15 m and 28 levels will be described. Finally, an analysis of the deformation of the columns will be presented.  相似文献   
43.
从不同来源角度对具有纳米银合成能力的微生物进行对比分析.主要针对4大类微生物来源,即矿物来源、海洋来源、植物与土壤来源以及其他来源,归纳总结各来源微生物还原制备纳米银的研究进展以及不同来源的优缺点.进一步对不同微生物的还原机理进行总结分析,还原机理包括胞内酶还原和其他胞内物质,例如多糖、多肽、吡啶等还原.最后,对合成纳...  相似文献   
44.
有机高分子絮凝剂的研究现状   总被引:3,自引:0,他引:3  
有机高分子絮凝剂由于具有用量少、生成的污染量小,且带有多种带电基团等优点而得到广泛应用.本文综述了国内外近几年来有机高分子絮凝剂在水处理等方面的应用情况,探讨了该絮凝剂在发展中存在的问题,并展望了未来絮凝剂的研究方向和发展趋势.  相似文献   
45.
Direct methanol fuel cells (DMFC), among the most suited and prospective alternatives for portable electronics, have lately been treated with nanotechnology. DMFCs may be able to remedy the energy security issue by having low operating temperatures, high conversion efficiencies, and minimal emission levels. Though, slow reaction kinetics are a significant restriction of DMFC, lowering efficiency and energy output. Nowadays, research is more focused on fundamental studies that are studying the factors that can improve the capacity and activity of catalysts. In DMFC, among the most widely explored catalysts are platinum and ruthenium which are enhanced in nature by the presence of supporting materials such as nanocarbons and metal oxides. As a result, this research sheds light on nanocatalyst development for DMFCs based on Platinum noble metal. To summarize, this research focuses on the structure of nanocatalysts, as well as support materials for nanocatalysts that can be 3D, 2D, 1D, or 0D. The support material described is made up of CNT, CNF, and CNW, which are the most extensively used because they improve the performance of catalysts in DMFCs. In addition, cost estimations for fuel cell technology are emphasized to show the technology's status and requirements. Finally, challenges to nanocatalyst development have been recognized, as well as future prospects, as recommendations for more innovative future research.  相似文献   
46.
An understanding of the similar and divergent metrics and methodologies underlying open government data benchmarks can reduce the risks of the potential misinterpretation and misuse of benchmarking outcomes by policymakers, politicians, and researchers. Hence, this study aims to compare the metrics and methodologies used to measure, benchmark, and rank governments' progress in open government data initiatives. Using a critical meta-analysis approach, we compare nine benchmarks with reference to meta-data, meta-methods, and meta-theories. This study finds that both existing open government data benchmarks and academic open data progress models use a great variety of metrics and methodologies, although open data impact is not usually measured. While several benchmarks’ methods have changed over time, and variables measured have been adjusted, we did not identify a similar pattern for academic open data progress models. This study contributes to open data research in three ways: 1) it reveals the strengths and weaknesses of existing open government data benchmarks and academic open data progress models; 2) it reveals that the selected open data benchmarks employ relatively similar measures as the theoretical open data progress models; and 3) it provides an updated overview of the different approaches used to measure open government data initiatives’ progress. Finally, this study offers two practical contributions: 1) it provides the basis for combining the strengths of benchmarks to create more comprehensive approaches for measuring governments’ progress in open data initiatives; and 2) it explains why particular countries are ranked in a certain way. This information is essential for governments and researchers to identify and propose effective measures to improve their open data initiatives.  相似文献   
47.
近些年随着人们生活水平的提高,中国人在美容方面的需求不断加大,使得医学美容行业的发展极具活力,与之相应的美容医疗设备及技术的未来市场容量将非常可观。  相似文献   
48.
聚甲醛的阻燃研究新进展   总被引:1,自引:0,他引:1  
聚甲醛是一类综合性能优异的工程塑料,但其热稳定性差,且极易燃烧。由于其结构的特点,聚甲醛的阻燃改性相对于其他塑料要困难得多,目前还是一个世界性的难题。综述了国内外近些年来在聚甲醛阻燃研究方面的新进展,并对其未来的发展方向进行了展望。  相似文献   
49.
河口泥沙通量研究综述   总被引:3,自引:3,他引:3  
河口泥沙通量的研究既是与全球变化研究有关的理论课题,也是与河口工程、经济生活关系密切的现实课题,本文系统地介绍了国内外关于河口泥沙通量研究的进展。泥沙通量研究多采用水文统计、机制分解、数学模型的方法进行,水文统计和机制分解无法达到预报的高度,相比之下,数学模型的优点很多,但由于河口海岸地区的泥沙运动规律复杂,其物理机制尚不完全清楚,阻碍了河口泥沙数学模型的发展。在深入分析基础上,文章就今后的河口泥沙通量研究工作提出了建议。  相似文献   
50.
Accurate and rapid assessment of the as-built status on any construction site provides the opportunity to understand the current performance of a project easily and quickly. Rapid project assessment further identifies discrepancies between the as-built and as-planned progress, and facilitates decision making on the necessary remedial actions. Currently, manual visual observations and surveying are the most dominant data capturing techniques but they are time-consuming, error-prone, and infrequent, making quick and reliable decision-making difficult. Therefore, research on new approaches that allow automatic recognition of as-built performance and visualization of construction progress is essential. This paper presents and compares two methods for obtaining point cloud models for detection and visualization of as-built status for construction projects: (1) A new method of automated image-based reconstruction and modeling of the as-built project status using unordered daily construction photo collections through analysis of Structure from Motion (SfM); (2) 3D laser scanning and analysis of the as-built dense point cloud models. These approaches provide robust means for recognition of progress, productivity, and quality on a construction site. In this paper, an overview of the newly developed automated image-based reconstruction approach and exclusive features which distinct it from other image-based or conventional photogrammetric techniques is presented. Subsequently the terrestrial laser scanning approach carried out for reconstruction and comparison of as-built scenes is presented. Finally the accuracy and usability of both of these techniques for metric reconstruction, automated production of point cloud models, 3D CAD shape modeling, and as-built visualizations is evaluated and compared on eight different case studies. It is shown that for precise defect detection or alignment tasks, image-based point cloud models may not be as accurate and dense as laser scanners' point cloud models. Nonetheless image-based point cloud models provide an opportunity to extract as-built semantic information (i.e., progress, productivity, quality and safety) through the content of the images, are easy to use, and do not need add burden on the project management teams by requiring expertise for data collection or analysis. Finally image-based reconstruction automatically provides photo alignment with point cloud models and enables image-based renderings which can remarkably impact automated performance monitoring and as-built visualizations.  相似文献   
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