A novel and convenient strategy for the synthesis of phthalazines from an aryne precursor

A novel three-step entry toward phthalazine derivatives has been elaborated. A strategy based on a sequential acyl-alkylation/diazo transfer reaction/Diaza-Wittig reaction led to the desired analogues in moderate to good yields from an aryne precursor. Various aryl groups were introduced on the annulated pyridazine, moreover the presence of an ester group allows further modifications.     

Synthesis of α-Alkylidene-β-Ethoxycarbonyl Cyclopentanones and -γ-Butyrolactones

Synthesis of (E,Z)-α-Alkylidene-β-ethoxycarbonyl cyclopentanones 5 and (E,Z)-α-alkylidene-γ-butyrolactones 7 by condensing phosphonates 3 or 6 with a variety of aldehydes in the presence of aqueous potassium carbonate (6-10M) as base is reported.     

Symbiotic signaling in actinorhizal symbioses

Actinorhizal symbioses are mutualistic associations between plants belonging to eight angiosperm families and soil bacteria of the genus Frankia. These interactions lead to the formation of new root organs, actinorhizal nodules, where the bacteria are hosted and fix atmospheric nitrogen thus providing the plant with an almost unlimited source of nitrogen for its nutrition. It involves an elaborate signaling between both partners of the symbiosis. In recent years, our knowledge of this signaling pathway has increased tremendously thanks to a series of technical breakthroughs including the sequencing of three Frankia genomes [1] and the implementation of RNA silencing technology for two actinorhizal species. In this review, we describe all these recent advances, current researches on symbiotic signaling in actinorhizal symbioses and give some potential future research directions.     

应用4变量精确平板理论分析FG复合板的自由振动

应用4变量的精确平板理论,对矩形功能梯度材料(FGM)复合板进行自由振动分析.与其它的理论不同,该理论的未知函数数量只有4个,而别的剪变形理论的未知函数为5个.提出的4变量精确平板理论,协调条件有了改变,与经典的薄板理论相比,许多方面有着惊人的相似,无需引入剪切修正因数——当横向剪应力越过板厚后,为了满足剪应力自由表面条件,出现抛物线状的改变,导致横向剪应力的变化.考虑了两种常见类型的FGM复合板,即,FGM表面层和各向同性夹芯层的复合板,以及各向同性表面层和FGM夹芯层的复合板.通过Hamilton原理,得到了FGM复合板的运动方程.得到闭式的Navier解,然后求解特征值问题,得到自由振动的基本频率.将该理论得到的结果,与经典理论,一阶的及其它更高阶的理论所得到的结果进行比较,检验了该理论的有效性.研究发现,该理论在求解FGM复合板自由振动性能方面,既精确又简单.     

Integral Domains Which Admit at Most Two Star Operations

In this article, we characterize domains which admit at most two star operations in the integrally closed and Noetherian cases. We also precisely count the number of star operations on an h-local Prüfer domain.     

Trivial Ring Extensions Defined by Arithmetical-Like Properties

In this article we investigate the transfer of the notions of elementary divisor ring, Hermite ring, Bezout ring, and arithmetical ring to trivial ring extensions of commutative rings by modules. Namely, we prove that the trivial ring extension R: = A ? B defined by extension of integral domains is an elementary divisor ring if and only if A is an elementary divisor ring and B = qf(A); and R is an Hermite ring if and only if R is a Bezout ring if and only if A is a Bezout domain and qf(A) = B. We provide necessary and sufficient conditions for R = A ? E to be an arithmetical ring when E is a nontorsion or a finitely generated A ? module. As an immediate consequences, we show that A ? A is an arithmetical ring if and only if A is a von Neumann regular ring, and A ? Q(A) is an arithmetical ring if and only if A is a semihereditary ring.     

Coupled coincidence point results on generalized distance in ordered cone metric spaces

In this paper, we establish some coupled coincidence point results in the setting of partially ordered cone metric spaces via $c$ -distance. We also proved some related coupled common fixed point theorems for such mappings. Our results generalize, extend, and unify several well-known comparable results in the literature regarding this topic. We present some examples to illustrate the concepts and results.     

Correction to: A comprehensive review on radioactive waste cycle from generation to disposal

Journal of Radioanalytical and Nuclear Chemistry - A correction to this paper has been published: https://doi.org/10.1007/s10967-021-07815-8     

Dynamic response of slacked single-walled carbon nanotube resonators

This paper presents an investigation of the dynamics of electrically actuated single-walled carbon nanotube (CNT) resonators including the effect of their initial curvature due to fabrication (slack). A nonlinear shallow arch model is utilized. A perturbation method, the method of multiple scales, is used to obtain analytically the forced vibration response due to DC and small AC loads for various slacked CNTs of higher and lower aspect ratio. Results of the perturbation method are verified with those obtained by numerically integrating the equations of a multi-mode reduced-order model based on the Galerkin procedure. The effective nonlinearity of the CNT is calculated as a function of the slack level and the DC load. To handle computational problems associated with CNTs of small radiuses, results based on a nonlinear cable model are also demonstrated. The results have indicated that the quadratic nonlinearity due to slack has dominant effect on the dynamic behavior of the CNT.