Ring Expansion to 6-, 7-, and 8-Membered Benzosilacycles through Strain-Release Silicon-Based Cross-Coupling

The synthesis of silacycles is highly appealing due to their important applications in organic synthesis, medicinal chemistry, and materials chemistry. However, sila-tetralins and sila-benzosuberanes are surprisingly under-represented due to a lack of general methods to access these compounds. We successfully developed a Pd-catalyzed strain-release silicon-based cross-coupling as an unprecedented ring-expansion method, which constitutes a general route for preparing diverse sila-tetralins and sila-benzosuberanes.     

Reaction of Vinyl Aziridines with Arynes: Synthesis of Benzazepines and Branched Allyl Fluorides

We report the cycloaddition between vinyl aziridines and arynes. Depending on the reaction conditions and the choice of the aryne precursor, the aziridinium intermediate can be trapped through two distinct mechanistic pathways. The first one proceeds through a formal [5+2] cycloaddition to furnish valuable multi-substituted benzazepines. In the second pathway, the aziridinium is intercepted by a fluoride ion to afford allylic fluorides in good yields. Both reactions proceed stereospecifically and furnish enantiopure benzazepines and allylic fluorides.     

Geometrically nonlinear large deformation analysis of triangular CNT-reinforced composite plates

A first known investigation on the geometrically nonlinear large deformation behavior of triangular carbon nanotube (CNT) reinforced functionally graded composite plates under transversely distributed loads is investigated. The analysis is carried out using the element-free IMLS-Ritz method. In this study, the first-order shear deformation theory (FSDT) and von Kármán assumption are employed to account for transverse shear strains, rotary inertia and moderate rotations. A convergence study is conducted by varying the supporting size and number of nodes. The effects of transverse shear deformation, CNT distribution and CNT volume fraction on the nonlinear bending characteristics under different boundary conditions are examined.     

A Hybrid Domain Decomposition and Multigrid Method for the Acceleration of Compressible Viscous Flow Calculations on Unstructured Triangular Meshes

This paper is concerned with the formulation and the evaluation of a hybrid solution method that makes use of domain decomposition and multigrid principles for the calculation of two-dimensional compressible viscous flows on unstructured triangular meshes. More precisely, a non-overlapping additive domain decomposition method is used to coordinate concurrent subdomain solutions with a multigrid method. This hybrid method is developed in the context of a flow solver for the Navier-Stokes equations which is based on a combined finite element/finite volume formulation on unstructured triangular meshes. Time integration of the resulting semi-discrete equations is performed using a linearized backward Euler implicit scheme. As a result, each pseudo time step requires the solution of a sparse linear system. In this study, a non-overlapping domain decomposition algorithm is used for advancing the solution at each implicit time step. Algebraically, the Schwarz algorithm is equivalent to a Jacobi iteration on a linear system whose matrix has a block structure. A substructuring technique can be applied to this matrix in order to obtain a fully implicit scheme in terms of interface unknowns. In the present approach, the interface unknowns are numerical fluxes. The interface system is solved by means of a full GMRES method. Here, the local system solves that are induced by matrix-vector products with the interface operator, are performed using a multigrid by volume agglomeration method. The resulting hybrid domain decomposition and multigrid solver is applied to the computation of several steady flows around a geometry of NACA0012 airfoil.     

三角模糊数判断矩阵理论及排序方法研究

由于三角模糊数运算的复杂性和特殊性,许多经典判断矩阵的理论并非完全适用于三角模糊数判断矩阵.首先指出目前文献中三角模糊数判断矩阵排序向量研究中存在的问题,并对经典判断矩阵的理论和性质在三角模糊数中是否完全适用进行了证明,然后基于已经证明在三角模糊数判断矩阵所适用的性质,分别建立了最小二乘法的三角模糊数互反互补判断矩阵目标优化模型,通过求解其模型可得到矩阵的权重向量,最后利用已有的三角模糊数排序公式求得决策结果.算例分析验证了该方法的正确性和有效性.     

基于一致性逼近的三角模糊数互补判断矩阵的排序方法

研究了元素为三角模糊数形式的互补判断矩阵的一致性和排序问题.分析了三角模糊数互补判断矩阵和三角模糊数互反判断矩阵之间的相互转换关系,提出了这两类判断矩阵完全一致性的概念并得到了三角模糊数互补判断矩阵的元素和排序权值之间的关系,在此基础上建立了一个多目标优化模型,通过求解该模型得到三角模糊数互补判断矩阵的排序向量,利用已有的模糊数比较大小公式得到方案的排序,最后给出了一个算例.