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81.
Derivation of baroclinic Ertel–Rossby invariant-based thermally-coupled vorticity equation in moist flow 下载免费PDF全文
For the potential vorticity (PV) invariant, there is a PV-based complete-form vorticity equation, which we use heuris- tically in the present paper to answer the following question: for the Ertel-Rossby invariant (ERI), is there a corresponding vorticity tendency equation? Such an ERI-based thermally-coupled vorticity equation is derived and discussed in detail in this study. From the obtained new vorticity equation, the vertical vorticity change is constrained by the vertical velocity term, the term associated with the slope of the generalized momentum surface, the term related to the horizontal vorticity change, and the baroclinic or solenoid term. It explicitly includes both the dynamical and thermodynamic factors' influence on the vorticity change. For the ERI itself, besides the traditional PV term, the ERI also includes the moisture factor, which is excluded in dry ERI, and the term related to the gradients of pressure, kinetic energy, and potential energy that reflects the fast-manifold property. Therefore, it is more complete to describe the fast motions off the slow manifold for severe weather than the PV term. These advantages are naturally handed on and inherited by the ERI-based thermally-coupled vorticity equation. Then the ERI-based thermally-coupled vorticity equation is further transformed and compared with the traditional vorticity equation. The main difference between the two equations is the term which describes the contribution of the solenoid term to the vertical vorticity development. In a barotropic flow, the solenoid term disappears, then the ERI-based thermally-coupled vorticity equation can regress to the traditional vorticity equation. 相似文献
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为深入了解人参皂苷的分子药理学特性,阐明人参皂苷与细胞膜的作用机制,利用拉曼光谱从分子水平研究了不同浓度人参皂苷Rb1与DPPC(二棕榈酰磷脂酸胆碱)双层膜的作用.结果表明,人参皂苷Rb1没有改变DPPC的极性头部O-C-C-N+的稳定构象,极性头仍然平行于膜表面.并且,拉曼峰值比I1096/I1126/1096/I1062和I2848/I288/0随着药物浓度的增加而相应的变大,说明Rbl增加了烃链的无序度,增强了双层膜的流动性.由此推测该药物与DPPC的作用可能由于皂苷分子内及分子间的氢键与磷脂双层膜的极性头部相作用而停留在膜的表面. 相似文献
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TiO2 nanotubes (TiO2NTs) are beneficial for photogenerated electron separation in photocatalysis. In order to improve the utilization rate of TiO2NTs in the visible light region, an effective method is to use Aun cluster deposition-modified TiO2NTs. It is of great significance to investigate the mechanism of Aun clusters supported on TiO2NTs to strengthen its visible-light response. In this work, the structures, electronic properties, Mulliken atomic charge, density of states, band structure, and deformation density of Aun (n = 1, 8, 13) clusters supported on TiO2NTs were investigated by DMOL3. Based on published research results, the most stable adsorption configurations of Aun (n = 1, 8, 13) clusters supported with TiO2NTs were obtained. The adsorption energy increased as the number of Au adatoms increased linearly. The Aun clusters supported on TiO2NTs carry a negative charge. The band gaps of the three most stable structures of each adsorption system decreased compared to TiO2NTs; the valence top and the conduction bottom of the Fermi level come mainly from the contribution of 5d and 6s-Au. The electronic properties of the 5d and 6s impurity orbitals cause valence widening and band gap narrowing. 相似文献
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Benefiting from the environmental friendliness of organic electrodes and the high security of aqueous electrolyte,an all-organic aqueous potassium dual-ion full... 相似文献
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金属卤化物钙钛矿半导体既在光伏器件研究中获得巨大进展,又在发光应用中体现出明显优势。金属卤化物钙钛矿半导体的荧光转化效率高、发光峰形窄、发射光谱可调控并可覆盖整个可见光范围,从而使得该类材料所制备的发光二极管有望满足下一代显示技术应用的性能要求。文章在简要叙述发光二极管基本原理的基础上,分别介绍了钙钛矿材料的结构和荧光特性、钙钛矿发光二极管的电致发光特性,以及钙钛矿发光二极管进入实际应用所必须解决的器件寿命、离子迁移和光谱不稳定性等主要技术问题,最后讨论了钙钛矿发光技术所面临的机遇和挑战。 相似文献
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