An incremental bundle method for portfolio selection problem under second-order stochastic dominance

Numerical Algorithms - We propose a preconditioner to accelerate the convergence of the GMRES iterative method for solving the system of linear equations obtained from discretize-then-optimize...     

链式多智能体遗传算法在分布式电源全时序上优化配置

分布式电源的选址与定容是微电网研究所面临的重要问题,本文主要考虑规划地区的24-h负荷时序特性和气候特点的24-h负荷变换的情况下的DG优化配置。针对以上问题,通过链式多智能体遗传算法对其进行优化处理。首先通过算法对IEEE33节点系统进行测试,验证算法在分布式电源优化配置中的优越性,并对PG E69节点配电网进行24-h时序的全过程模拟仿真优化,结果验证了多智能体遗传算法能在分布式电源配置上的有效性,同时提高微电网接入的预测精度,加快收敛速度,改进陷入局部最优的可能性等问题,对微电网在规划选址与定容选择上提供工程参考的实用性。     

Effects of locally resonant modes on underwater sound absorption in viscoelastic materials

Recently, by introducing locally resonant scatterers with spherical shape proposed in phononic crystals into design of underwater sound absorption materials, the low-frequency underwater sound absorption phenomenon induced by the localized resonances is observed. To reveal this absorption mechanism, the effect of the locally resonant mode on underwater sound absorption should be studied. In this paper, the finite element method, which is testified efficiently by comparing the calculation results with those of the layer multiple scattering method, is introduced to investigate the dynamic modes and the corresponding sound absorption of localized resonance. The relationship between the resonance modes described with the displacement contours of one unit cell and the corresponding absorption spectra is discussed in detail, which shows that the localized resonance leads to the absorption peak, and the mode conversion from longitudinal to transverse waves at the second absorption peak is more efficient than that at the first one. Finally, to show the modeling capability of FEM and investigate shape effects of locally resonant scatterers on underwater sound absorption, the absorption properties of viscoelastic materials containing locally resonant scatterers with ellipsoidal shape are discussed.     

单向耦合映象格子的时空混沌同步

以耦合映象格子为对象,研究了时空混沌系统的同步问题. 基于Lyapunov稳定性定理,通过恰当地选择驱动函数,实现了两个单向耦合映象格子的完全同步. 仿真模拟验证了这种同步方法的有效性. 讨论了控制参量对同步速率的影响. 仿真模拟还表明,在存在系统偏差并受到噪声影响的情况下,仍然可以实现两系统的同步,这种同步方法具有一定的抗干扰能力. 关键词： 时空混沌 同步 耦合映象格子     

Monodisperse Six-Armed Starbursts based on Truxene-Cored Multibranched Oligofluorenes: Design,Synthesis, and Stabilized Lasing Characteristics

A series of monodisperse six-armed conjugated starbursts ( Tr1F , Tr2F , and Tr3F ) containing a truxene core and multibranched oligofluorene bridges capped with diphenylamine (DPA) units has been designed, synthesized, and investigated as robust gain media for organic semiconductor lasers (OSLs). The influence of electron-rich DPA end groups on their optoelectronic characteristics has been discussed at length. DPA cappers effectively raise HOMO levels of the starbursts, thus enhancing the hole injection and transport ability. Solution-processed electroluminescence devices based on the resulting six-armed starbursts exhibited efficient deep-blue electroluminescence with clear reduced turn-on voltages (3.2–3.5 V). Moreover, the resulting six-armed molecules showed stabilized electroluminescence and amplified spontaneous emission with low thresholds (27.4–63.9 nJ pulse⁻¹), high net gain coefficients (80.1–101.3 cm⁻¹), and small optical loss (2.6–4.4 cm⁻¹). Distributed feedback OSLs made from Tr3F exhibited a low lasing threshold of 0.31 kW cm⁻² (at 465 nm). The results suggest that the construction of truxene-centered six-armed conjugated starbursts with the incorporation of DPA units can effectively enhance EL properties by precisely regulating the HOMO energy levels, and further optimizing their optical gain properties.     

Regulating PdC3/PtC3···thiophene interaction by small molecule doping (AgOTf,CuBr, CuI,CuBr2, PdCl2)

Structural Chemistry - The influences of small molecule doping on PdC3/PtC3···thiophene interaction have been investigated by atoms in molecules (AIM) theory, electron location...     

Synthesis of γ-(Arylamino)butyric Acid Derivatives via Ring-Opening Addition of Arylamines to Cyclopropane-1,1-Dicarboxylates

Russian Journal of Organic Chemistry - A rapid and efficient catalytic approach has been proposed for the synthesis of dimethyl 2-[2-(aryl-amino)but-3-en-1-yl]- and...     

Enhanced targeted energy transfer for adaptive vibration suppression of pipes conveying fluid

Nonlinear Dynamics - In this paper, a nonlinear energy sink and a negative stiffness element are integrated for achieving enhanced, passive, and adaptive vibration suppression for a pipe conveying...