The Simulation and Improvement of Particle Swarm Optimization Based on Cellular Automata

AbstractWe observed that PSO algorithm was easily falling into local extreme point by using cellular automata simulation, and developed several improvement strategies which drew inspiration from simulation, such as adding additional particle into updated formula, introducing crossover operator and mutation disturbance when the premature convergence occurs. The experiments validated new algorithm on 10 benchmark functions, and results showed that the improved PSO algorithm has better stability and higher accuracy

Chemical characterisation and source apportionment of atmospheric quasi-ultra-fine particulate matter (PM0.36): seasonality and spatio-temporal variability

This thesis investigated the sources contributing to the organic carbon fraction of quasi-UFP (here PM0.36), itsseasonal variation and temporal-spatial variability. An in-situ derivatization thermal desorption gas chromatography time-of-flight mass spectrometry method was applied to PM0.36 for simultaneous quantification of primary andorganic markers. 5 sources including both primary and secondary sources were resolved by positive matrixfactorization (PMF) modeling based on measured organic species.Die vorgelegte Dissertation hat die quellenabhängige Zusammensetzung der organischen Kohlenstofffraktion der quasi-ultrafeinen Partikel (hier: PM0.36), deren jahreszeitbedingte Variation und deren zeitliche und räumliche Variabilität untersucht. Quantifizierung von primären und sekundären organischen Markerverbindungen wurde die In-situ-Derivatisierung-Thermodesorptions-Gaschromatographie, gekoppelt mit Flugzeitmassenspektrometrie, eingesetzt. Fünf Quellen konnten mit der positiven Matrixfaktorisierung (PMF) aufgelöst werden, basierend auf den gemessenenorganischen Verbindungen

Guided ion beam and theoretical study of the reactions of Au+ with H2, D2, and HD

Journal ArticleReactions of the late third-row transition metal cation Au+ with H2, D2, and HD are examined using guided ion beam tandem mass spectrometry. A flow tube ion source produces Au+ in its 1S (5d10) electronic ground state level. Corresponding state-specific reaction cross sections for forming AuH+ and AuD+ as a function of kinetic energy are obtained and analyzed to give a 0 K bond dissociation energy of D0(Au+?H) = 2.13 ? 0.11 eV. Quantum chemical calculations at the B3LYP/HW+/6- 311+G(3p) and B3LYP/Def2TZVPP levels performed here show good agreement with the experimental bond energy. Theory also provides the electronic structures of these species and the reactive potential energy surfaces. We also compare this third-row transition metal system with previous results for analogous reactions of the first-row and second-row congeners, Cu+ and Ag+. We find that Au+ has a stronger M+?H bond, which can be explained by the lanthanide contraction and relativistic effects that alter the relative size of the valence s and d orbitals. Results from reactions with HD provide insight into the reaction mechanism and indicate that ground state Au+ reacts largely via a direct mechanism, in concordance with the behavior of the lighter group 11 metal ions, but includes more statistical behavior than these metals as well

Electrochemical deposition of Mg(OH)2/GO composite films for corrosion protection of magnesium alloys

AbstractMg(OH)2/graphene oxide (GO) composite film was electrochemical deposited on AZ91D magnesium alloys at constant potential. The characteristics of the Mg(OH)2/GO composite film were investigated by scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffractometer (XRD) and Raman spectroscopy. It was shown that the flaky GO randomly distributed in the composite film. Compared with the Mg(OH)2 film, the Mg(OH)2/GO composite film exhibited more uniform and compact structure. Potentiodynamic polarization tests revealed that the Mg(OH)2/GO composite film could significantly improve the corrosion resistance of Mg(OH)2 film with an obvious positive shift of corrosion potential by 0.19 V and a dramatic reduction of corrosion current density by more than one order of magnitude

Pareto Optimality of Centralized Procurement Based on Genetic Algorithm

In the process of purchasing materials, small enterprises are often unable to meet the minimum availability of suppliers in the process of purchasing due to the lack of economic strength and storage capacity of goods. Therefore, they will encounter difficulties in the process of purchasing.To solve this problem, the group-led centralized procurement strategy for small enterprises has become a new craze. In this paper, we transform the problem of centralized procurement lot into a multi-objective optimization problem by establishing a multi-objective optimization model with cost, quality and logistics as sub-objectives, and use genetic algorithms to solve the multi-objective optimization problem in order to achieve Pareto optimality among each purchaser and supplier. Finally, an example of procurement by the China Energy Investment Corporation is used to verify that the multi-objective optimization model for the collection of lots constructed in this paper can effectively promote the cooperation between purchasers and suppliers, and stimulate the competitive vitality of enterprises in the market

A New Double Color Image Watermarking Algorithm Based on the SVD and Arnold Scrambling

We propose a new image watermarking scheme based on the real SVD and Arnold scrambling to embed a color watermarking image into a color host image. Before embedding watermark, the color watermark image W with size of M×M is scrambled by Arnold transformation to obtain a meaningless image W~. Then, the color host image A with size of N×N is divided into nonoverlapping N/M×N/M pixel blocks. In each (i,j) pixel block Ai,j, we form a real matrix Ci,j with the red, green, and blue components of Ai,j and perform the SVD of Ci,j. We then replace the three smallest singular values of Ci,j by the red, green, and blue values of W~ij with scaling factor, to form a new watermarked host image A~ij. With the reserve procedure, we can extract the watermark from the watermarked host image. In the process of the algorithm, we only need to perform real number algebra operations, which have very low computational complexity and are more effective than the one using the quaternion SVD of color image

Giant second-harmonic generation in photonic crystal slabs possessing double-resonance bound states in the continuum

The ability to confine and guide light makes photonic crystals (PhCs) a promising platform for large local field enhancement, which enables efficient nonlinear processes at the nanoscale. Here, we utilize optical bound states in the continuum (BICs) to engineer sharp resonances with high quality factors. By investigating the angleresolved reflection spectra, we demonstrate that two PhC slabs with different configuration but the same lattice constant support a pair of at-Γ and a pair of off-Γ resonances, respectively. In both cases, BIC-type resonances are observed at the fundamental frequency while BIC-like resonances are found at the second harmonic. This double-resonance phenomenon is subsequently used to significantly enhance the second-harmonic generation from PhC slabs. The maximum values of the SHG are several orders of magnitude larger than those corresponding to the reference slabs. We consider that our approach based on double-resonance BICs provides a novel way to realize enhanced harmonic generation in photonic nanodevices