Iodine-Promoted Domino Oxidative Cyclization for the One-Pot Synthesis of Novel Fused Four-Ring Quinoxaline Fluorophores by sp3 C−H Functionalization

A method for the synthesis of novel fused four-ring quinoxaline skeleton has been described by an I₂ promoted sp³ C−H functionalization between 1,2,3,3-tetramethyl-3H-indolium iodides and 1,2-diamines. This transformation proceeds smoothly under metal- and peroxide-free conditions through a sequential iodination, oxidation, annulation and rearrangement. Moreover, 8,9-dichloro-5,12,12-trimethyl-2-(trifluoromethyl)-5,12-dihydroquinolino[2,3-b]quinoxaline showed good photophysical properties and was used in live cell imaging, indicating the potential value of this skeleton as a fluorophore in probes.     

氧化铝包覆层对甲烷燃烧反应钯催化剂活性结构的稳定作用

<正>甲烷具有高的温室效应,因此天然气应用过程尾气中甲烷的消除是一个迫切和亟待解决的环境问题~1。Pd基催化剂广泛应用于催化甲烷燃烧反应,并且表现出显著的结构敏感性~2。实验和理论计算研究结果均表明Pd-Pd Ox界面表现出最高的催化甲烷燃烧活性~(3,4)。但是,在强放热甲烷燃烧反     

Mittag–Leffler stability of nabla discrete fractional-order dynamic systems

Nonlinear Dynamics - In the present study, the definition of discrete Mittag–Leffler stability is derived to characterize convergence rule of the pseudostates for nabla discrete...     

Direct knitting privileged molecular catalysts into recyclable single-site catalysts with enhanced activity

正An ideal strategy for catalyst immobilization is taking advantage of the widely well studied homogeneous molecular catalysts and transforming them directly into highly efficient and recyclable heterogeneous catalysts. However, the obtained heterogeneous catalysts often have inferior activity due to altered chemical environment around active centers and decreased mass/heat transfer [1,2]. Porous materials     

Improved 3D reconstruction method based on the Scheimpflug principle

Optical Review - This paper proposes a 3D reconstruction scheme for monocular cameras based on an improved line structure cursor positioning method and the Scheimpflug principle to overcome the...     

N-substituted-3(10H)-acridones as visible-light photosensitizers for organic photoredox catalysis

N-Substituted-3(10H)-acridones have been established as visible-light organic photocatalyst. These photosensitizers are efficient for oxidative coupling reaction of N-aryl tetrahydroisoquinolines with various nucleophiles. Notably, N-methyl-3(10H)-acridone (Ia) is stable and can be effectively prepared. It is a water-soluble and atom-economic catalyst, and thus holds promise for green chemical applications. Mechanistic studies confirm a single electron transfer (SET)-induced radical process and a rate-limiting step. Analysis of the photocatalytic reactivity?structure relationship reveals that the acridones are robust and tunable photosensitizers for photoredox catalysis.     

两种非晶碳化硅薄膜发光二极管

利用硅烷与甲烷的混合气在射频电场下的等离子体反应,淀积不同导电类型的非晶碳化硅薄膜,制成了p-i-n结注入型和均匀材料的碰撞电离型两种大面积发光二极管。本文报导这两种非晶发光器件的结构设计及光谱特性,并对器件的发光机现进行了讨论。     

~1H-NMR对部分酯化聚醚端羟基分析及分子量测定

通过测量部分酯化聚醚和全酯化聚醚的酯氢~1H-NMR吸收峰面积的积分比率计算端羟基比例,且用酯氢测定聚醚分子量。     

基于传输线等效法的双腔体屏蔽系数快速算法

传输线等效法（TLM）是一种常用的开孔腔屏蔽系数快速计算方法,在孔缝耦合系数的计算中考虑了孔缝处的场模式,提高了TLM算法在高频段计算屏蔽系数（SE）的准确性。继而将TLM算法推广到开孔双金属腔屏蔽系数的计算,通过将外腔体中任意位置的电压等效为内孔缝处的辐射电压源,计算得到内腔体中任意位置上的屏蔽系数,解决了已有文献中方法的不足。该算法计算结果与CST仿真结果吻合较好。     

Explicit exact solutions for a new generalized Hamiltonian amplitude equation with nonlinear terms of any order

Making use of a proper transformation and a generalized ansatz, we consider a new generalized Hamiltonian amplitude equation with nonlinear terms of any order, iu_x + u_tt + (|u|^p + |u|^2p)u + u_xt = 0. As a result, many explicit exact solutions, which include kink-shaped soliton solutions, bell-shaped soliton solutions, periodic wave solutions, the combined formal solitary wave solutions and rational solutions, are obtained.Received: April 4, 2002