关于剩余幺半群的锥与序

利用剩余和锥给出了剩余幺半群的偏序关系的一种刻划,得到了剩余幺半群的商是偏序群的一个充要条件     

一类多时滞中立型种群对数模型的正周期解

通过更精确的先验估计,利用重合度理论中的连续定理,研究了一类时滞种群模型的周期解,获得了这类模型存在正周期解的充分条件,所得结果推广了李永民的有关结论,并使条件有所减弱.     

基于本体的知识结构拓扑图的智能图书馆模型研究

本体、智能语义检索、可视化检索、推荐系统算法都是图书馆的智能化关键技术,这四者都与图书的知识结构有着密切的关联。基于本体的知识结构拓扑图是通过关联规则算法挖掘出来的,由领域专家确定,然后由图书本体来承载的图书知识间内在的修后集成的复杂关系图,将这种图书本体应用到智能图书馆中,将进一步提高智能系统的效率和可视化效果。     

Graph-based discovery and analysis of atomic-scale one-dimensional materials

Recent decades have witnessed an exponential growth in the discovery of low-dimensional materials (LDMs), benefiting from our unprecedented capabilities in characterizing their structure and chemistry with the aid of advanced computational techniques. Recently, the success of two-dimensional compounds has encouraged extensive research into one-dimensional (1D) atomic chains. Here, we present a methodology for topological classification of structural blocks in bulk crystals based on graph theory, leading to the identification of exfoliable 1D atomic chains and their categorization into a variety of chemical families. A subtle interplay is revealed between the prototypical 1D structural motifs and their chemical space. Leveraging the structure graphs, we elucidate the self-passivation mechanism of 1D compounds imparted by lone electron pairs, and reveal the dependence of the electronic band gap on the cationic percolation network formed by connections between structure units. This graph-theory-based formalism could serve as a source of stimuli for the future design of LDMs.     

Critical couplings in topological-insulator waveguide-resonator systems observed in elastic waves

Waveguides and resonators are core components in the large-scale integration of electronics, photonics and phononics, both in existing and future scenarios. In certain situations, there is critical coupling of the two components; i.e. no energy passes through the waveguide after the incoming wave couples into the resonator. The transmission spectral characteristics resulting from this phenomenon are highly advantageous for signal filtering, switching, multiplexing and sensing. In the present study, adopting an elastic-wave platform, we introduce topological insulator (TI), a remarkable achievement in condensed matter physics over the past decade, into a classical waveguide-ring-resonator configuration. Along with basic similarities with classical systems, a TI system has important differences and advantages, mostly owing to the spin-momentum locked transmission states at the TI boundaries. As an example, a two-port TI waveguide resonator can fundamentally eliminate upstream reflections while completely retaining useful transmission spectral characteristics, and maximize the energy in the resonator, with possible applications being novel signal processing, gyro/sensing, lasering, energy harvesting and intense wave–matter interactions, using phonons, photons or even electrons. The present work further enhances confidence in using topological protection for practical device performance and functionalities, especially considering the crucial advantage of introducing (pseudo)spins to existing conventional configurations. More in-depth research on advancing phononics/photonics, especially on-chip, is foreseen.