367 research outputs found

    新疆欧夜鹰繁殖生态初报

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    欧夜鹰(Caprimulgus europaeus)属夜行性鸟类。广泛分布于新疆荒漠地区,如乌鲁木齐、阿勒泰、克拉玛依、昌吉州、吐鲁番、哈密、阿克苏、库尔勒、喀什等地区(Ma,2001)。因其繁殖行为

    The efficiency of WUA management in the Lower Seyhan Irrigation Project

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    Policy Uncertainty and the Long-term Investment of Companies

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    在全球经济面临下行的大背景下,各国政府机构以及监管机构都在全球经济金融中扮演着积极的角色,接踵而来的便是各国频繁地出台各类政策法规,尤其是在被媒体形容为“黑天鹅齐飞”的2016年,各国政府的下一步行动变得更加难以预测。而公司在这种环境中运行,自然面临着不小的政策不确定风险。本文的研究对象和研究变量均来源于此。国内学者陈国进等人利用芝加哥大学和斯坦福大学联合发布的经济政策不确定指数(EPUIndex),探讨了经济政策不确定性对企业行为的影响以及作用机制。本文在系统性地介绍了这些不确定性尤其是政策不确定性文献的基础上,补充并扩展了前人的研究,增大了构建指数的样本,运用更科学的编程技术,构建了属于中...In the background of the global economy facing downward, all national government agencies and regulators play an active role in global economy, and frequently introduce various policies and regulations, especially in the so-called ‘Black Swan Event’ year of 2016. The next steps took by governments have become more difficult to predict. Operating in such environment, it’s undoubt that the companies...学位:保险硕士院系专业:经济学院_保险硕士学号:1562014115209

    海水富营养化评价方法的研究进展与应用现状

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    简要概述了海水富营养化的概念及对生态系统的影响。介绍了几类常用的海水富营养化评价方法,包括单因子法、富营养化指数法、水质指数法和营养状态质量法等国内常用的评价方法,以及近年来国际上发展起来的以富营养化症状为考虑因素的第二代海水富营养评价方法,包括综合评价法、河口富营养化评价法和波罗的海行动计划等,第二代方法的评价标准更为细化,对富营养化带来的环境效应也提供一定的判断标准。阐述了现阶段我国海水富营养化评价方法的应用现状,尤其是在近海河口区域针对富营养化程度进行的区域等级划分,旨在提出各种海水富营养化评价方法应用现状和特点,为不同海域在选用富营养化评价方法提供参考。最后,对海水富营养化评价的应用方向提出未来展望,给出水质监测管理以及海洋生态环境灾害预测防御的指导性建议。国家重点研发计划海洋环境安全保障专项“中国近海与太平洋高分辨率生态环境数值预报系统”(编号:2016YFC1401605);;国家自然科学基金青年科学基金项目“南海低营养级生态模型营养盐循环过程的数值模拟研究”(编号:41206023)资助~

    Optimization of Microwave-Assisted Extraction Technology for Pingtang Capsules B by Orthogonal Test

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    目的:优选平糖胶囊b方的微波辅助提取工艺。方法:采用微波辅助提取平糖胶囊b方,以栀子苷提取量为检测指标,选择微波功率、料液比、提取时间、提取次数为考察指标,通过正交试验优选微波辅助提取工艺。采用HPlC测定栀子苷含量,色谱条件为dIAMOnSIlTMrP C18色谱柱(4.6 MMx250 MM,5μM),流动相乙腈-水(11∶89),流速1.0 Ml·MIn-1,检测波长238 nM,柱温室温,进样量20μl。结果:最佳工艺条件为微波功率15 kW,料液比1∶5,提取时间20 MIn,提取数2次,栀子苷平均提取量9.08 Mg·g-1。结论:优选的微波辅助提取工艺具有高效、节能、省时等优点,具有极大的工业化推广价值。Objective: To optimize microwave-assisted extraction technology of Pingtang capsules B.Method: Pingtang capsules B was extracted by microwave assisted technology,with yield of geniposide as index,choosing microwave power, material-liquid ratio, extraction time, extraction times as investigating factors,orthogonal test was adopted to optimize microwave assisted extraction technology.The content of geniposide was determined by HPLC,chromatographic conditions were as follows: DiamonsilTMRP C18column(4.6 mm × 250mm,5 μm),mobile phase of acetonitrile-water(11∶ 89),flow rate 1.0 mL·min- 1,detection wavelength 238nm,column temperature at room temperature,injection volume 20 μL.Result: Optimum extraction technology conditions were as follows: microwave power 15 kW,solid-liquid rate 1∶ 5,extraction time 20 min,extraction 2times; Under these conditions,average yield of geniposide was 9.08 mg·g- 1.Conclusion: Optimized microwave assisted extraction technology had advantages of high efficiency, energy saving and time saving with great application value for industrial production of Pingtang capsules B.厦门市科技局科研项目(3502Z20044013
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