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针对现有进口还书机成本高、结构复杂的问题,根据目前我国图书馆普遍人工办理还书工作的现状,利用平面曲柄摇杆机构原理设计的图书馆用智能还书机,克服了还书机高价位、普及难、通用性差的不足,实现了还书的自助性和自主性及随机性。现场试验及试运行证实该设计方案可靠,对图书馆实现智能管理、延伸服务空间时间具有实用性,对智能还书机的研发具有借鉴和推广价值。 相似文献
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将常规萃取精馏、差压热耦合萃取精馏以及隔壁塔萃取精馏技术应用于以糠醛为萃取剂的苯和环己烷共沸物分离过程。在稳态模型的基础上,利用Aspen Dynamics软件进行控制研究,对三工艺流程提出了若干控制策略。结果表明,对于常规萃取精馏过程,再沸器热负荷与进料量比值控制结构在降低控制过程超调量方面表现出明显优势;对于差压热耦合萃取精馏过程,带有压力-补偿控温策略的方案控制效果更佳;而对于隔壁塔,则选择了无隔板下方气液分离比控制的结构来作为较优的控制策略。 相似文献
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Y2O3: Eu nanocrystals were synthesized by EDTA complexing sol-gel process at a relatively low temperature, in which ethylen-diamine-tetraacetic acid (EDTA) and polyethylene glycol (PEG) were used as the chelating agent and polymerization agent respectively. Formation process of Y2O3:Eu and structure characterization were carried out by TG-DTA, XRD, SEM/EDX. The results show that pure cubic phase Y203: Eu nanocrystalsere is produced after the precursor calcinated at 600℃ for 2 h, and the crystallinity increases with increasing calcination temperature. The nanoparticles of the Y2O3: Eu are basically spherical in shape. The mean particle size increases from about 30 to 70 nm when the calcination temperature increases from 600 to 1000℃. The luminescent properties of phosphor were analyzed by measuring the excitation and emission spectra. The main emission peak of the sample is around 612 nm, resulting in a red emission. The emission intensity increases with the calcination temperature. Compared with microsized Y2O3: Eu phosphors prepared by a conventional method, nanosized Y2O3: Eu synthesized by the present work, gives and a clear red shift in the emission spectrum. Moreover, the quenching concentration of Eu is raised. 相似文献
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固相微萃取技术是一种新型的样品前处理技术,它将取样、萃取、浓缩等过程合并在一个操作步骤中完成,不需要有机萃取剂,是一种简便快捷的样品前处理技术。文章在系统地介绍SPME的发展、原理、装置、影响因素的基础上,阐述了近年来固相微萃取技术在环境分析中的应用,并预测了今后的发展趋势。 相似文献