Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： The Qinghai-Tibet Plateau is the source of major Asian rivers such as the Yangtze River, the Yellow River, and the Yarlung Zangbo River, which is known as Asia’s water tower. Analysis on the evolution rule and variation trend of surface water and groundwater resources in the Qinghai-Tibet Plateau is of great strategic and scientific importance to the water resources, water ecological protection, and future regional development of the Qinghai-Tibet Plateau. Based on the analysis of the observed runoff series of hydrological stations in the main rivers within source areas, it is found that the surface runoffs in most areas of the Qinghai-Tibet Plateau show an increasing trend impacted by climate change in terms of more precipitation and rising temperature, and indicates significant changes in seasonal processes. The runoffs increase more significantly in the source areas of the Yangtze, Nujiang, and Yarlung Zangbo rivers. The results demonstrate that the dominant factor is increased glacier and snow melting flow to more groundwater and growth of plateau lakes, due to temperature rising. With the depletion of glacier and snowpack, the melting water will be reduced in future. Therefore, the break point of increase to decrease will arise in some river runoffs. Thus, the water security of this region will face new problems and challenges. High attention should be paid to the global change impact to water resources evolution in the Qinghai-Tibet Plateau, and positive responsive measures should be taken.
Subjects: Chemistry >> Applied Chemistry submitted time 2020-03-05
Abstract： [Objective] Synthesis of potential neroprotective agent catalpol perpropionylated derivative (CP-6), and determination of the optimal microwav-assisted synthesis conditions. [Methods] CP-6 was synthesized by microwave-assisted synthesis (MCAS) using catalpol and propionyl anhydride as raw materials and pyridine as solvent and acid-binding agent. It was characterized by FT-IR, HRMS, NMR and assayed for neuroprotective activity by MTT method. [Results] When the molar ratio of propionic anhydride to catalpol is 18, the concentration of catalol in pyridine is 25 g/L, the reaction temperature of microwave reactor is 80 ℃, and the reaction time is 6 h, the yield of CP-6 can reach 98.51%. CP-6 has potential neroprotective activity."
Peer Review Status:
Awaiting Review
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-15 Cooperative journals: 《金属学报》
Abstract：对2219-T8铝合金搅拌摩擦焊 (FSW) 接头在拉伸过程中, 热机械影响区 (TMAZ) 的变形行为、断裂途径和190 MPa下微区电化学性能进行了研究. 研究表明, 焊接热循环和搅拌作用加权强化效果最弱的区域是强度最差的位置；拉伸时接头变形主要发生在TMAZ, 但由于受到焊核区的拘束程度不同, TMAZ下层应变更大, 导致裂纹起源于下层；在相同的应力水平下, TMAZ表面的钝化膜更易破裂, 甚至会有微裂纹出现, 这使得当接头处于应力腐蚀环境中时, TMAZ更易发生局部腐蚀, 导致接头的抗应力腐蚀能力下降.
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