A high‐order element based adaptive mesh refinement strategy for three‐dimensional unstructured grid

Adaptive mesh refinement (AMR) shows attractive properties in automatically refining the flow region of interest, and with AMR, better prediction can be obtained with much less labor work and cost compared to manually remeshing or the global mesh refinement. Cartesian AMR is well established; however, AMR on hybrid unstructured mesh, which is heavily used in the high‐Reynolds number flow simulation, is less matured and existing methods may result in degraded mesh quality, which mostly happens in the boundary layer or near the sharp geometric features. User intervention or additional constraints, such as freezing all boundary layer elements or refining the whole boundary layer, are required to assist the refinement process. In this work, a novel AMR strategy is developed to handle existing difficulties. In the new method, high‐order unstructured elements are first generated based on the baseline mesh; then the refinement is conducted in the parametric space; at last, the mesh suitable for the solver is output. Generating refined elements in the parametric space with high‐order elements is the key of this method and this helps to guarantee both the accuracy and robustness. With the current method, 3‐dimensional hybrid unstructured mesh of huge size and complex geometry can be automatically refined, without user intervention nor additional constraints. With test cases including the 2‐dimensional airfoil and 3‐dimensional full aircraft, the current AMR method proves to be accurate, simple, and robust.     

KMnO4-mediated direct selective radical cross-coupling: An effective strategy for C2 arylation of quinoline N-oxide with arylboronic acids

Direct C—H functionalization of quinoline N-oxides with arylboronic acids is achieved using KMnO_4 as the sole and efficient oxidative system.This method provides an efficient protocol to construct regioselectively 2-arylquinoline N-oxides via radical cross-coupling reaction in moderated to good yields under mild conditions.     

A finite volume scheme preserving extremum principle for convection–diffusion equations on polygonal meshes

We propose a nonlinear finite volume scheme for convection–diffusion equation on polygonal meshes and prove that the discrete solution of the scheme satisfies the discrete extremum principle. The approximation of diffusive flux is based on an adaptive approach of choosing stencil in the construction of discrete normal flux, and the approximation of convection flux is based on the second‐order upwind method with proper slope limiter. Our scheme is locally conservative and has only cell‐centered unknowns. Numerical results show that our scheme can preserve discrete extremum principle and has almost second‐order accuracy. Copyright © 2017 John Wiley & Sons, Ltd.     

The Structural Fate of Individual Multicomponent Metal‐Oxide Nanoparticles in Polymer Nanoreactors

Multicomponent nanoparticles can be synthesized with either homogeneous or phase‐segregated architectures depending on the synthesis conditions and elements incorporated. To understand the parameters that determine their structural fate, multicomponent metal‐oxide nanoparticles consisting of combinations of Co, Ni, and Cu were synthesized by using scanning probe block copolymer lithography and characterized using correlated electron microscopy. These studies revealed that the miscibility, ratio of the metallic components, and the synthesis temperature determine the crystal structure and architecture of the nanoparticles. A Co‐Ni‐O system forms a rock salt structure largely owing to the miscibility of CoO and NiO, while Cu‐Ni‐O, which has large miscibility gaps, forms either homogeneous oxides, heterojunctions, or alloys depending on the annealing temperature and composition. Moreover, a higher‐ordered structure, Co‐Ni‐Cu‐O, was found to follow the behavior of lower ordered systems.     

Cu(OAc)2-catalyzed direct radical C2 arylation of quinoline N-oxide with arylamines

A Cu(OAc)₂-catalyzed synthesis of 2-arylquinoline N-oxides with easily available arylamines is described. The main features of this reaction are mild reaction conditions, high functional-group tolerance, excellent regioselectivity, and good to excellent yields. This procedure is mild, operationally simple, and constitutes a greener approach to the arylation of quinoline N-oxides.     

基于ASP.NET的网络课程资源库系统设计与实现

分析了网络课程资源库系统功能需求、设计流程和界面,及系统实现的关键技术,包括注册登录、站内搜索等模块的实现技术和系统安全性保障技术。测试结果表明,该系统实现了网络课程资源库系统的基本功能。     

曲靖旅游产业升级策略研究

旅游业作为第三产业的支柱产业之一，低污染、低能耗的特点使其备受各级政府的重视。曲靖市旅游业拥有宜人的气候、丰富的资源、发达的经济等优势，但是也存在着观光旅游的景点知名度相对较低、基础性公共服务部门的服务意识薄弱、旅游配套设施不足等问题。为此，应通过科学规划，大力发展休闲游、自驾游等方式，以促进整个旅游业的产业升级。