Oxidatively Induced Selective Carbon-Carbon Bond Formation From Isolated Rhodium(III) Complexes

This work focuses on oxidatively induced regioselective intramolecular C−C bond formations based on the Rh^III complexes synthesized from dirhodium(II) trifluoroacetate with 2-arylpyridines. With the selection of electron-donating groups on the arene rings of 2-arylpyridines, the unusual meta-ortho C−C bond-forming was favored, which led to the formation of meta-substituted 2-arylpyridine homocoupling dimers. On the contrary, the electron-withdrawing groups have tendency to occur conventional ortho-ortho bond-forming, resulting in the formation of new Rh^III complexes possessing the intriguing Rh^III(TFA)₃ fragment. Preliminary mechanistic experiments suggest that the sequential oxidation of Rh^III occurred in the reaction.     

纳米增强预浸料缠绕立管参数敏感性分析

复合材料立管结构参数与立管力学性能存在紧密的关联性,掌握设计参数对缠绕立管力学性能的影响规律非常必要．考虑缠绕工艺引起的孔隙缺陷,基于复合材料弹性理论及孔隙微观理论模型,构建了纳米增强预浸料缠绕立管形变模型;其次,采用局部敏感度分析法,分别讨论了缠绕立管应力与位移对孔隙含量、孔隙形状、纳米颗粒含量、纤维体积含量、缠绕层数、缠绕角度及内压的局部敏感性;最终,数值结果表明：孔隙含量对轴向应力的影响局部敏感性较强,在孔隙含量为2.8 %~3.2 %之间时,轴向应力的局部敏感性数值快速从负数增长到正值;而孔隙的引入,使得其它设计参数对立管应力与位移的局部敏感性数值的变化趋势无明显影响,但大大影响了敏感性的数值大小;此外,径向位移对孔隙、纳米颗粒含量等所有参数明显不敏感．     

Pricing and strategy selection in a closed-loop supply chain under demand and return rate uncertainty

Closed-loop supply chain (CLSC) decision-making involves many uncertainties, which makes the decision-making process more complex and diversified. This study considered a two-stage CLSC consisting of an original manufacturer and a third-party recycler. Without any government policy support, considering the effects of market demand, product return rate, and consumer perceived value, a CLSC decision model based on market demand with a [0,1] distribution was established. The model analyzes three situations—a manufacturer monopoly, the Cournot duopoly game, and the Stackelberg competition game—and solves them. The optimal values of decision variables such as optimal pricing, market demand, and all parties’ profits in the CLSC are obtained, and a strict mathematical proof is given. Through the model-solving process, the effects of product return rate and consumer perceived value on decision variables are analyzed; then, the profit allocation between the original manufacturer and the third-party recycler under different cooperation modes is analyzed. In addition, the four combinations of competition and cooperation are analyzed based on game theory. The Nash equilibrium solution and Pareto optimal solution of the four modes are analyzed by drawing a bimatrix Nash equilibrium table. The results indicate that the cooperation–cooperation mode is difficult to produce automatically, and government policy guidance and support are often needed to achieve Pareto optimality. Finally, a numerical example is given to validate the proposed model. In this way, the proposed model provides reliable theoretical support for the decision-making of both sides in a CLSC.