基于蚁群算法的网络层析故障链路诊断

为了解决网络层析成像中链路故障诊断的NP难问题,提出一种基于蚁群算法的故障链路诊断方法。首先将问题建模成一个组合优化问题,利用蚁群算法在解决组合优化问题中独特的优势进行求解。不同于传统的蚁群算法,求解故障链路时蚁群在初始放置点和可行路径上都受约束。为了加快算法的收敛速度,对蚁群算法的初始信息素浓度进行优化。仿真结果表明,所提出的算法在故障链路检测中具有较好的精度和召回率。     

Syntheses and Crystal Structures of Silver(I) Complexes by Depolymerizing [Ag(C≡CPh)]_n with a NP_3 Ligand

1 INTRODUCTION Great attention has currently been paid to com-pounds formed by the reaction between phosphineand metal alkynyl building blocks[1]. The ligand NP3contains one tertiary nitrogen atom as well as threephosphorous atoms and bonds to the metal ions as atetradentate ligand, affording tetrahedral[2] or triangle-bipyrimidal geometry[3, . In other coordination ca- 4]ses, one[5, , two[7], three P donors[8, 6] …     

Role of self‐assembly conditions and amphiphilic balance on nanoparticle formation of PEG‐PDLLA copolymers in aqueous environments

The production of well‐defined and reproducible polymeric nanoparticles (NPs), in terms of size and stability in biological environments, is undoubtedly a fundamental challenge in the formulation of novel and more effective nanomedicines. The adoption of PEGylated lactide (LA) block copolymers as biodegradable and biocompatible nanocarriers at different clinical stages has rendered these materials an attractive polymeric platform to be exploited and their formulation is further understood. In the present work, we synthesized a library of linear polyethylene glycol‐poly(D,L‐lactide) block copolymers with different lengths of LA (15, 25, 50, and 100 LA units) via simple and metal‐free ring‐opening polymerization, in order to alter the amphiphilic balance of the different macromolecules. The produced polymers were formulated into NPs while varying a series of key parameters in the solvent displacement process, including solvent:nonsolvent ratios and the nature of the two media, and the effect on size and stability was assessed. In addition, stability to protein–NPs interaction and aggregation was studied, highlighting the different NP final properties according to the nature of the amphiphilic balance and nanoformulation conditions. Therefore, we have illustrated a systematic and methodological process to optimize a series of NPs parameters balancing particle size, size distribution, surface charge, and stability to guide future works in the nanoformulation field. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 1801–1810     

Chiral recognition by enantioselective liquid chromatography: Mechanisms and modern chiral stationary phases

An overview of the state-of-the-art in LC enantiomer separation is presented. This tutorial review is mainly focused on mechanisms of chiral recognition and enantiomer distinction of popular chiral selectors and corresponding chiral stationary phases including discussions of thermodynamics, additivity principle of binding increments, site-selective thermodynamics, extrathermodynamic approaches, methods employed for the investigation of dominating intermolecular interactions and complex structures such as spectroscopic methods (IR, NMR), X-ray diffraction and computational methods. Modern chiral stationary phases are discussed with particular focus on those that are commercially available and broadly used. It is attempted to provide the reader with vivid images of molecular recognition mechanisms of selected chiral selector–selectand pairs on basis of solid-state X-ray crystal structures and simulated computer models, respectively. Such snapshot images illustrated in this communication unfortunately cannot account for the molecular dynamics of the real world, but are supposed to be helpful for the understanding. The exploding number of papers about applications of various chiral stationary phases in numerous fields of enantiomer separations is not covered systematically.     

Understanding chicken walks on n × n grid: Hamiltonian paths,discrete dynamics,and rectifiable paths

Understanding animal movements and modeling the routes they travel can be essential in studies of pathogen transmission dynamics. Pathogen biology is also of crucial importance, defining the manner in which infectious agents are transmitted. In this article, we investigate animal movement with relevance to pathogen transmission by physical rather than airborne contact, using the domestic chicken and its protozoan parasite Eimeria as an example. We have obtained a configuration for the maximum possible distance that a chicken can walk through straight and nonoverlapping paths (defined in this paper) on square grid graphs. We have obtained preliminary results for such walks which can be practically adopted and tested as a foundation to improve understanding of nonairborne pathogen transmission. Linking individual nonoverlapping walks within a grid‐delineated area can be used to support modeling of the frequently repetitive, overlapping walks characteristic of the domestic chicken, providing a framework to model fecal deposition and subsequent parasite dissemination by fecal/host contact. We also pose an open problem on multiple walks on finite grid graphs. These results grew from biological insights and have potential applications. © 2014 The Authors. Mathematical Methods in the Applied Sciences published by John Wiley & Sons Ltd.     

Preparation and the optical nonlinearity of surface chemistry improved titania nanoparticles in poly(methyl methacrylate)-titania hybrid thin films

With 800-nm, 120-fs laser pulses, optical nonlinearity has been studied in a series of thin films containing poly(methyl methacrylate) (PMMA), filled with surfactant acetylacetone (Acac) capped TiO₂ nanoparticles, which were synthesized by a simple in situ sol-gel/polymerization process, assisted by spin coating and multi-step baking. The resulting nanohybrid thin films have highly optical transparency and demonstrate a unique nonlinear optical (NLO) response. The highest nonlinear refractive index (n₂) is observed up to 6.55 × 10⁻² cm² GW⁻¹ in the nanohybrid thin film of 60 wt% Ti(OBu)₄ in PMMA, with a negligible two-photon absorption (TPA), as confirmed by the Z-scan technique. The titanium precursor loading combined with the nature of the capping molecules are used to influence the ability of nanoparticles to nonlinear optical response. Indeed, the ligands at the nanoparticles’ surface can not only control the extent of the interaction between the organic molecules and the embedded nanoparticles but also influence the optical nonlinearities of nanoparticles.     

DNA编码技术探讨

文中研究了DNA编码的一般约束条件-编码距离的各种情况,找出了其中的某些等价计算,对任意两个编码序列的编码距离提出了最简化的计算方法,降低了基于汉明距离约束的计算复杂度。同时,文中还分析了Adleman哈密尔顿路径实验中采用的编码性能,提出了全新的性能更好的编码,并设计了生物验证实验进行验证。     

Minimizing the Size of Vertexlights in Simple Polygons

We show that given a simple Polygon P it is NP‐hard to determine the smallest α ∈ [0, π] such that P can be illuminated by α‐vertexlights, if we place exactly one α‐vertexlight in each vertex of P.