高阶脉冲时滞微分方程解的振动准则(英文)

本文研究了一类n阶线性脉冲时滞微分方程解的振动性。通过比较原理,得到了其振动的充分条件,所得到的结果推广了一些已有的结果。     

Identification of the hydrogen utilization pathway for the electrocatalytic hydrogenation of phenol

Electrochemical hydrogenation(ECH) of biomass-derived platform molecules is a burgeoning route for the sustainable utilization of hydrogen. However, the noble-metal-catalyzed ECH of phenolic compounds suffers from intense competition with hydrogen evolution reaction. We prepared Pt Rh bimetallic nanoparticles dispersed on highly ordered mesoporous carbon nanospheres, which improves the utilization efficiency of adsorbed hydrogen(Had) to ECH in H–UPD region(0 V vs. RHE).Further analysis reveals(i) the strong overlapping between the d-orbitals of Pt and Rh enhances specific adsorption of phenol;(ii)incorporation of Rh devotes an electronic effect on weakening the alloy–Hadinteraction to increase the FE of ECH. DFT calculations confirm the selectivity difference and the ECH parallel pathways: cyclohexanol and cyclohexanone are formed via hydrogenation/dehydrogenation of the intermediate *C6 H10 OH. These findings deepen our fundamental understanding of the ECH process, and cast new light on exploration of highly efficient electrocatalysts for biomass upgrading.     

1-甲基-3,4-二苯基喹啉-2(1H)-酮的合成和结构表征

以N-甲基苯胺和苯丙炔酸为原料,经过缩合、亲电环化、偶联反应合成了1-甲基-3,4-二苯基喹啉-2(1H)-酮;利用核磁共振谱和气相色谱-质谱表征了产物的结构.结果表明,所用合成方法具有产率高、反应条件温和、操作简单等优点,目标产物的总产率达62.7%.     

完全二部图K3,3与星Sn的积图的交叉数

确定图的交叉数是NP-完全问题．目前有关完全二部图与星图的积图的交叉数结果并不多．引入了一些新的收缩技巧,建立了积图K3,3□Sn与完全三部图K3,3□Sn之间的交叉数关系．从而,为进一步完全确定积图K3,3□Sn的交叉数提供了一条新途径．     

A space-dependent atomic superfluid current in Bose–Einstein condensates

A space-dependent atomic superfluid current with an explicit analytical expression and its role in Bose–Einstein condensates are studied. The factors determining the intensity and oscillating amplitude of the space-dependent atomic superfluid current are explored in detail. Research findings reveal that the intensity of the current can be regulated by setting an appropriate configuration of the trap and its oscillating amplitude can be adjusted via Feshbach resonance. It is numerically demonstrated that the space-dependent atomic superfluid current can exert great influence on the spatial distribution of condensed atoms, and even force condensed atoms into very complex distributional states with spatial chaos.     

Global Phase Portraits of Symmetrical Cubic Hamiltonian Systems with a Nilpotent Singular Point

Han et al. [Han et al., Polynomial Hamiltonian systems with a nilpotent critical point, J. Adv. Space Res. 2010, 46, 521–525] successfully studied local behavior of an isolated nilpotent critical point for polynomial Hamiltonian systems. In this paper, we extend the previous result by analyzing the global phase portraits of polynomial Hamiltonian systems. We provide 12 non-topological equivalent classes of global phase portraits in the Poincar´ e disk of cubic polynomial Hamiltonian systems with a nilpotent center or saddle at origin under some conditions of symmetry.     

Existence and stability of almost periodic solutions for shunting inhibitory cellular neural networks with time-varying delays

In this paper, the shunting inhibitory cellular neural networks (SICNNs) with time-varying delays are considered. Sufficient conditions for the existence and local exponential stability of the almost periodic solutions are established by using fixed point theorem, Lyapunov functional method and differential inequality techniques. The results of this paper are new and they complement previously known results.     

耗散Jaynes-Cummings模型中微观与唯象学主方程方法的比较

在有耗散的Jaynes-Cummings模型中,对原子与腔复合系统初始处于贝尔态或是原子激发态而腔场为真空态时分别运用微观与唯象学主方程进行求解,并分析这两类主方程在不同耦合区域的区别．结果显示,在强耦合和大失谐情况下,微观主方程求解得到的原子基态的布居数呈线性增长,但唯象学主方程获得的结果却呈非线性增加．在弱耦合区域,这两类主方程求解得到的原子基态布居数都出现快速增加,但是用唯象学主方程要比用微观主方程得到的布居数增加得更快．通过分析与讨论,该结果可能对耗散的腔QED中更好的实现逻辑门提供理论参考．     

Periodicity and multi-periodicity generated by impulses in delayed differential inclusions: application to discontinuous Nicholson’s blowflies model

Nonlinear Dynamics - Based on Krasnoselskii’s fixed point theorem of set-valued maps type, this paper studies the existence and multiplicity of periodic positive solutions for delayed...