587 research outputs found
Direct Realization of Digital Differentiators in Discrete Domain for Active Damping of LCL-Type Grid-Connected Inverter
Plasmonic Bubbles in n-Alkanes
In this paper we study the formation of microbubbles upon the irradiation of
an array of plasmonic Au nanoparticles with a laser in n-alkanes
(, with n = 5-10). Two different phases in the evolution of the
bubbles can be distinguished. In the first phase, which occurs after a delay
time {\tau}d of about 100 {\mu}s, an explosive microbubble, reaching a diameter
in the range from 10 {\mu}m to 100 {\mu}m, is formed. The exact size of this
explosive microbubble barely depends on the carbon chain length of the alkane,
but only on the laser power . With increasing laser power, the delay time
prior to bubble nucleation as well as the size of the microbubble both
decrease. In the second phase, which sets in right after the collapse of the
explosive microbubble, a new bubble forms and starts growing due to the
vaporization of the surrounding liquid, which is highly gas rich. The final
bubble size in this second phase strongly depends on the alkane chain length,
namely it increases with decreasing number of carbon atoms. Our results have
important implications for using plasmonic heating to control chemical
reactions in organic solvents
cis-Diaquabis(2,2′,2′′-tripyridylamine)zinc(II) bis(perchlorate)
In the title compound, [Zn(2,2′,2′′-tpa)2(H2O)2](ClO4)2 (2,2′,2′′-tpa is 2,2′,2′′-tripyridylamine, C15H12N4), the Zn center lies on a twofold axis and is coordinated octahedrally by two water molecules and two bidentate 2,2′,2′′-tpa ligands. The perchlorate anions are linked to the coordinated water molecules in the complex cations via O—H⋯O hydrogen bonds
Test-Sheet Composition Using Analytic Hierarchy Process and Hybrid Metaheuristic Algorithm TS/BBO
Due to the shortcomings in the traditional methods which dissatisfy the examination requirements in composing test sheet, a new method based on tabu search (TS) and biogeography-based optimization (BBO) is proposed. Firstly, according to the requirements of the test-sheet composition such as the total score, test time, chapter score, knowledge point score, question type score, cognitive level score, difficulty degree, and discrimination degree, a multi constrained multiobjective model of test-sheet composition is constructed. Secondly, analytic hierarchy process (AHP) is used to work out the weights of all the test objectives, and then the multiobjective model is turned into the single objective model by the linear weighted sum. Finally, an improved biogeography-based optimization—TS/BBO is proposed to solve test-sheet composition problem. To prove the performance of TS/BBO, TS/BBO is compared with BBO and other population-based optimization methods such as ACO, DE, ES, GA, PBIL, PSO, and SGA. The experiment illustrates that the proposed approach can effectively improve composition speed and success rate
Solvent Exchange in a Hele-Shaw Cell Universality of Surface Nanodroplet Nucleation
Solvent exchange (also called solvent shifting or Ouzo effect) is a generally
used bottom-up process to mass-produce nanoscale droplets. In this process, a
good solvent for some oil is displaced by a poor one, leading to oil
nanodroplet nucleation and subsequent growth. Here we perform this process on a
hydrophobic substrate so that sessile droplets so-called surface
nanodroplets-develop, following the work of Zhang et al. [Zhang, X.; Lu, Z.;
Tan, H.; Bao, L.; He, Y.; Sun, C.; Lohse, D. Proc. Natl. Acad. Sci. U.S.A.
2015, 122, 9253-9257]. In contrast to what was done in that paper, we chose a
very well-controlled Hele-Shaw geometry with negligible gravitational effects,
injecting the poor solvent in the center of the Hele-Shaw cell, and
characterize the emerging nanodroplets as a function of radial distance and
flow rates. We find that the mean droplet volume per area _area strongly
depends on the local Peclet number Pe and follows a universal scaling law
_area~Pe^(3/4). Moreover, the probability distribution function of the
droplet volume strongly depends on the local Pe as well, regardless of the flow
rates and radial distance, giving strong support to the theoretical model of
the solvent exchange process developed in Zhang et al.'s work.Comment: 6 pages, 5 figure
A Highly Robust Single-Loop Current Control Scheme for Grid-Connected Inverter with an Improved LCCL Filter Configuration
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