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目的:建立测定维生素B12滴眼液有关物质的HPLC法。方法:用十八烷基硅烷键合硅胶为填充剂;0.05mol/L磷酸二氢钾-乙腈(86:14),用磷酸调pH值至3.0为流动相;检测波长为361nm。结果:空白辅料对有关物质检查无干扰,主成分峰与杂质峰的分离度符合规定。结论:本方法专属性强、结果准确可靠,可用于维生素B12滴眼液有关物质的测定。 相似文献
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Extending previous investigations by Loeb of mobilities in gaseous mixtures using his procedure except that the auxiliary field in these measurements was made equal to the advancing field thus giving absolute values of the mobilities, measurements of mobilities were made in mixtures of CH3NO2H2 and CH3CNH2. The mobilities in H2 were 7.12 for the positive ions and 10.46 for the negative ions in cm./sec. per volt/cm. Those in CH3NO2 were 0.221 cm./sec. per volt/cm. for both ions and in CH3CN they were 0.234 cm./sec. per volt/cm. for both ions. Both ion mobilities deviated from Blanc's law in CH3NO2 indicating the formation of complexes with the CH3NO2 ions somewhat greater in size than the normal ions in H2. The molecules attached to negative ions somewhat less readily than to the positive ions but both final ions were of the same size. In CH3CN mixtures both positive and negative ions deviated from Blanc's law, the positive ion showing more ready attachment of CH3CN. The negative ion had consistently a higher mobility than the positive ion, a circumstance indicating a smaller ion and suggesting that the attaching molecule might not be CH3CN but some impurity. Both ion addition products in CH3CN are larger than the normal ion in H2 but smaller than those in CH3NO2 as was to be expected. 相似文献
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本文介绍了采用高能球磨法制备出纳米CeO2/Zn、纳米CeO2/A1复合粉末,用粉末冶金真空热压烧结制备出纳米CeO2/Zn、纳米CeO2/Ai复合材料块体的方法. 相似文献
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<正>In recent years, theoretical proposals for exotic states in quantum magnets are developing very rapidly, but many of these intriguing quantum phases and transitions have been difficult to realize experimentally. One class of such states is the valence bond solid, in which spins entangle locally and form symmetry-breaking singlet patterns. 相似文献
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正交LiMnO2以其独有的特性,作为正极材料有着优良的表现,本文针对其缺点进行掺杂改性研究,使用凝胶溶胶法制备正极材料,研究了不同比例掺杂镍元素对其作为正极材料性能的影响,采用XRD,SEM,充放电测试等手段对该材料的结构和电化学性能进行了表征. 相似文献
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本文以商业生态系统理论、开放式创新理论以及价值来源模型为基础,以腾讯科技有限公司为案例代表,阐释开放战略演化过程中,商业生态系统的商业模式产生了怎样的变化。研究发现:(1)企业在较为封闭的状态下,虽然通过垄断机制与并购机制形成市场份额上的优势,但却极大得阻碍了产业创新、破坏了产业生态链(2)在众创空间介入开放战略前,企业已经开始了以线上为主的孵化机制探索,线上的主体多为二元且相互关系多为单向性,再加之物理位置的缺失、单一的合作关系,导致了商业模式中的效率的单方面增强,互补性、锁定性与新颖性都较低;(3)众创空间介入后,企业开放度得到扩展,核心企业通过提供线下物理空间的拓展实现资源开放与信息透明化、创造了高效的信息交流渠道、促进多样化合作伙伴关系等,使得整个生态系统呈现多元主体、环绕式、合作关系多样化的稳定结构,使得商业模式中的四个维度都得到了提高。 相似文献
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借助CiteSpace V软件,以Web of Science数据库2007—2016年间2 424篇创新创业代表文献为对象,采用文献共被引网络、关键词共现网络及突现词分析等方法对创新创业国际研究进行计量分析。研究得出:当前创新创业国际研究热点主要聚焦于开放式创新、创新公司、发展中国家、深度访谈方法和创新活动等领域;形成由区域创新系统到企业所有权、服务行业、社会创业、企业绩效和知识溢出理论,再到商业模式的7个阶段组成要素分析与演化路径;研究发展趋势主要将在知识溢出理论、企业绩效、商业模式与社会创业4个方面展开。在此基础上提出相关对策建议,以期为未来创新创业研究与实践提供借鉴与范式。 相似文献
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