Shandong Normal University

About: Shandong Normal University is a education organization based out in Jinan, Shandong, China. It is known for research contribution in the topics: Laser & Catalysis. The organization has 12378 authors who have published 12576 publications receiving 174572 citations.

Cloudde: A Heterogeneous Differential Evolution Algorithm and Its Distributed Cloud Version

Abstract: Existing differential evolution (DE) algorithms often face two challenges. The first is that the optimization performance is significantly affected by the ad hoc configurations of operators and parameters for different problems. The second is the long runtime for real-world problems whose fitness evaluations are often expensive. Aiming at solving these two problems, this paper develops a novel double-layered heterogeneous DE algorithm and realizes it in cloud computing distributed environment. In the first layer, different populations with various parameters and/or operators run concurrently and adaptively migrate to deliver robust solutions by making the best use of performance differences among multiple populations. In the second layer, a set of cloud virtual machines run in parallel to evaluate fitness of corresponding populations, reducing computational costs as offered by cloud. Experimental results on a set of benchmark problems with different search requirements and a case study with expensive design evaluations have shown that the proposed algorithm offers generally improved performance and reduced computational time, compared with not only conventional and a number of state-of-the-art DE variants, but also a number of other distributed DE and high-performing evolutionary algorithms. The speedup is significant especially on expensive problems, offering high potential in a broad range of real-world applications.

Characterizing topological charge of optical vortices by using an annular aperture.

Abstract: We explore the spatial frequency property of the far-field diffraction intensity pattern of an optical vortex after passing through an annular aperture in detail. The result reveals that the spatial spectrum consists of alternate bright and dark rings and, in particular, the number of the bright rings is nicely identical to the absolute value of the topological charge. Based on this property, we present and demonstrate a simple technique to characterize the topological charge of an optical vortex through its diffraction intensity pattern after an annular aperture.

3D silver nanoparticles with multilayer graphene oxide as a spacer for surface enhanced Raman spectroscopy analysis.

Abstract: We report a three-dimensional (3D) SERS substrate with different numbers of silver nanoparticle (Ag NP) layers using multilayer graphene oxide (GO) as a spacer. The SERS performance of the 3D nanostructure was investigated and it was found that the SERS effect increased as the number of Ag NP layers increased, and showed almost no change for more than four layers. We found that the SERS performance of the 3D nanostructures can be mainly attributed to the topmost hot spots which are closely related to the Ag NP layers in the 3D nanostructure. Furthermore, we explored 3D nanostructures with different Ag NP layers using the finite difference time domain method (FDTD). The 3D SERS substrates also exhibit excellent detection capability. The limit of detection (LOD) was calculated down to 10−15 M for R6G and 10−12 M for CV. In addition, the reproducibility of the 3D SERS substrate was attributed obviously to the increasing number of Ag NP layers. Based on these promising results, the highly sensitive detection of molecules such as malachite green was demonstrated for food safety inspection.

Electrochemical Synthesis, Voltammetric Behavior, and Electrocatalytic Activity of Pd Nanoparticles

Abstract: Size-controlled Pd nanoparticles were electrochemically synthesized in large quantities at room temperature through the direct electroreduction of bulk PdCl42- ions in the presence of poly(N-vinylpyrrolidone) (PVP), a water-soluble polymer. The technological key to electrochemical synthesis of Pd particles is that PVP greatly promoted the formation process of Pd particles and inhibited the electrodeposition process of Pd onto the Pt cathode at the same time besides effectively stabilizing the formed Pd nanoparticles. The as-synthesized Pd nanoparticles display the voltammetric behavior significantly different from the bulk Pd and also present a high catalytic activity toward the electrooxidation of methanol.