关联字母矩阵基模算法在水污染中的应用

系统反馈基模分析是系统动力学中把握系统结构,揭示系统产生涌现性原因的一种重要工具。目前针对系统反馈基模分析的方法有流率基本入树法和向量生成法等等。为了更好地从系统反馈基模分析得到有效的管理对策并更快地从极小基模生成复杂系统问题,提出一个确定复杂系统的基模生成集并对新管理措施进行反馈绩效分析的关联字母矩阵算法。该算法是将系统动力学的因果关系图转化为关联字母矩阵,以此计算反馈环将更为简单、直观。最后,用一个管理案例阐明了该算法的实际价值:运用此方法对我国现今亟需解决的水污染环境问题进行深度剖析,并根据所得到的系统基模提出了一些管理建议和对策。 更多还原     

Three‐dimensional visible‐light capsule enclosing perfect supersized darkness via antiresolution

Supersized darkness in three dimensions surrounded by all light in free space is demonstrated theoretically and experimentally in the visible regime. The object staying in the darkness is similar to staying in an empty light capsule because light just bypasses it by resorting to destructive interference. A binary‐optical system is designed and fabricated based on achieving antiresolution (AR), by which electromagnetic energy flux avoids and bends smoothly around a nearly perfect darkness region. AR remains an unexplored topic hitherto, in contrast to the super‐resolution for realizing high spatial resolution. This novel scheme replies on smearing out the point spread function and thus poses less stringent limitations upon the object's size and position since the created dark (zero‐field) area reach 8 orders of magnitude larger than λ² in cross‐sectional size. It functions very well with arbitrarily polarized beams in three dimensions, which is also frequency scalable in the whole electromagnetic spectrum.     

Optimization‐free superoscillatory lens using phase and amplitude masks

A superoscillatory focusing lens has been experimentally demonstrated by optimizing Fresnel zone plates (FZP), with limited physical insight as to how the lens feature contributes to the focal formation. It is therefore imperative to establish a generalized viable account for both FZP (amplitude mask) and binary optics (phase mask). Arbitrary superoscillatory spots can now be customized and realized by a realistic optical device, without using optimization. It is counterintuitively found that high spatial frequency with small amplitude and destructive interference are favorable in superfocusing of a superoscillation pattern. The inevitably high sidelobe is pushed 15λ away from the central subwavelength spot, resulting in significantly enlarged field of view for viable imaging applications. This work therefore not only reveals the explicit physical role of any given metallic/dielectric rings but also provides an alternative design roadmap of superresolution imaging. The robust method is readily applicable in superthin longitudinally polarized needle light, quantum physics and information theory.     

Automated eigensystem realisation algorithm for operational modal analysis

The eigensystem realisation algorithm (ERA) is one of the most popular methods in civil engineering applications for estimating modal parameters. Three issues have been addressed in the paper: spurious mode elimination, estimating the energy relationship between different modes, and automatic analysis of the stabilisation diagram. On spurious mode elimination, a new criterion, modal similarity index (MSI) is proposed to measure the reliability of the modes obtained by ERA. On estimating the energy relationship between different modes, the mode energy level (MEL) was introduced to measure the energy contribution of each mode, which can be used to indicate the dominant mode. On automatic analysis of the stabilisation diagram, an automation of the mode selection process based on a hierarchical clustering algorithm was developed. An experimental example of the parameter estimation for the Chaotianmen bridge model in Chongqing, China, is presented to demonstrate the efficacy of the proposed method.     

Enhancement of GaAs/InGaAs quantum well emission by disordered gold nanoparticle arrays

Coupling effect of surface plasmon (SP) with InGaAs/GaAs QW emission is demonstrated experimentally. The SP resonance is generated by disordered arrays of Au nanodisks on the InGaAs/GaAs QW surface. More than twofold enhancement in QW PL is observed. Theoretical simulations also indicated that the disordered arrays of Au structures enlarged the cone angle for which light can be radiated out. The larger angle enhances the PL intensity.     

Provably secure three-party key agreement protocol using Chebyshev chaotic maps in the standard model

Recently, several key agreement protocols based on Chebyshev chaotic maps have been proposed in the literature. However, they can normally achieve “heuristic” security, that is, once drawbacks are found in these protocols, they are either modified to resist the new attacks, or are discarded. Under these circumstances, it is necessary and significant to define standard security models that can precisely characterize the capabilities of the participants and a potent adversary. Hence, we propose to use public key encryption based on enhanced Chebyshev chaotic maps and pseudo-random function ensembles to construct an efficient three-party key agreement protocol under the standard model, in which the adversary is able to make a wider range of queries and have more freedom than the other proposed schemes. In the design of our protocol, we follow the ideas in the recent key agreement protocol of Yang and Cao’s. The proposed protocol is shown to be provably secure if decisional Diffie–Hellman problem, which is based on Chebyshev chaotic maps, is computationally infeasible. To the best of our knowledge, our protocol is the first provably secure 3PAKE protocol using Chebyshev chaotic maps under the standard model.     

基于特征重聚焦网络的多尺度近岸舰船检测

针对监控视频中的多尺度近岸舰船检测问题,提出了一种基于特征重聚焦网络的舰船目标检测算法,设计了由多维特征聚合模块(MFAM)与注意力特征重构模块(AFRM)组成的特征重聚焦策略.其中,MFAM基于输入的特征金字塔构建特征聚合块,进一步融合多尺度舰船不同层次特征的语义信息.AFRM基于多分支空洞卷积以及通道与空间注意力机制提升网络对目标非局部信息的表征和对背景干扰的抑制,并构建了用于目标检测的特征重聚焦金字塔.在Seaships7000舰船公开数据集上的实验结果表明,相比其他算法,本算法对监控视频中多尺度近岸舰船的检测效果更好.     

Paper-based electrochemiluminescent 3D immunodevice for lab-on-paper, specific, and sensitive point-of-care testing

Recent research on microfluidic paper-based analytical devices (μPADs) has shown that paper has great potential for the fabrication of low-cost diagnostic devices for healthcare and environmental monitoring applications. Herein, electrochemiluminescence (ECL) was introduced for the first time into μPADs that were based on screen-printed paper-electrodes. To further perform high-specificity, high-performance, and high-sensitivity ECL on μPADs for point-of-care testing (POCT), ECL immunoassay capabilities were introduced into a wax-patterned 3D paper-based ECL device, which was characterized by SEM, contact-angle measurement, and electrochemical impedance spectroscopy. With the aid of a home-made device-holder, the ECL reaction was triggered at room temperature. By using a typical tris(bipyridine)ruthenium-tri-n-propylamine ECL system, this paper-based ECL 3D immunodevice was applied to the diagnosis of carcinoembryonic antigens in real clinical serum samples. This contribution further expands the number of sensitive and specific detection modes of μPADs.     

A novel high selectivity chemiluminescence sensor for fenvalerate based on double-sided hollow molecularly imprinted materials

Novel fenvalerate double-sided hollow molecularly imprinted microspheres (fenvalerate-DHMIMs) were fabricated by in situ polymerization with the help of mesoporous silica microspheres (MSMs) in this paper for the very first time. Scanning electron microscope was employed to characterize the surface morphology of the fenvalerate-DHMIMs. Taking advantage of the quenching effect of fenvalerate on the luminol-H(2)O(2)-NaOH chemiluminescence system, a new model was established to determine fenvalerate by a highly selective flow injection chemiluminescence method. The traditional flow-through cell was replaced by a novel Y-shaped column. The chemiluminescence intensity was linear with fenvalerate concentration over the range of 5.0 × 10(-8) to 2.0 × 10(-5) g mL(-1) and the detection limit was 2.2 × 10(-8) g mL(-1). The relative standard deviation (RSD) for the determination of 2.0 × 10(-6) g mL(-1) fenvalerate was 1.4% (n = 11). The proposed method was applied to the determination of fenvalerate in real samples with satisfactory results.     

The impact of human activity patterns on asymptomatic infectious processes in complex networks

The study of the impact of human activity patterns on network dynamics has attracted a lot of attention in recent years. However, individuals’ knowledge of their own physical states has rarely been incorporated into modeling processes. In real life, for certain infectious processes, infected agents may not have any visible or physical signs and symptoms; therefore, they may believe that they are uninfected even when they have been infected asymptomatically. This infection awareness factor is covered neither in the classical epidemic models such as SIS nor in network propagation studies. In this article, we propose a novel infectious process model that differentiates between the infection awareness states and the physical states of individuals and extend the SIS model to deal with both asymptomatic infection characteristics and human activity patterns. With regards to the latter, we focus particularly on individuals’ testing action, which is to determine whether an individual is infected by an epidemic. The simulation results show that less effort is required in controlling the disease when the transmission probability is either very small or large enough and that Poisson activity patterns are more effective than heavy-tailed patterns in controlling and eliminating asymptomatic infectious diseases due to the long-tail characteristic.