The formation mechanism of space charges in polyimide (PI) which was exposed to dielectric barrier discharge (DBD) in SF6 medium and the effects of the space charges on interfacial and electrical properties of PI were investigated. The variation of normalized surface charge density on PI sample was calculated and illustrated for different DBD exposure times. The surface potential was measured to determine the effect of the space charges on the sample. Then, the contact angle values were measured to obtain the relation between the surface energy and the surface charge density. The expressions for the total charge and the concentration of trapped electrons were derived by using Poisson and continuity equations at stationary state. The space charges were determined experimentally by using thermally stimulated depolarization current (TSDC) method. Also, SEM image and FTIR spectrum of virgin and treated samples were presented to observe the structural variations. It was seen that the approach for the formation mechanism of the space charges agreed with the experimental data. However, it was concluded particularly for the short-time DBD treatments that the space charges accumulated in the sample should be considered besides the effects of surface functionalization in the determination of the surface energy.
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http://dx.doi.org/10.1155/2013/890454 | DOI Listing |
Acc Chem Res
January 2025
Department of Chemistry, University of California, Berkeley, California 94720, United States.
ConspectusThe electronic properties of atomically thin van der Waals (vdW) materials can be precisely manipulated by vertically stacking them with a controlled offset (for example, a rotational offset─i.e., twist─between the layers, or a small difference in lattice constant) to generate moiré superlattices.
View Article and Find Full Text PDFOptical misalignment between transmitter and receiver leads to power loss and mode crosstalk in a mode division multiplexing (MDM) free-space optical (FSO) link. We report both numerical simulations and experimental results on the propagation performance of two typical vector beams, C-point polarization full Poincaré beams (FPB), and V-point polarization cylindrical vector beams (CVB), compared to homogeneous polarization scalar vortex beams (SVB) under optical misalignment. The FSO communication performance under misalignment using different transmit beams is evaluated in terms of power loss, mode crosstalk, power penalty, etc.
View Article and Find Full Text PDFJ Biotechnol
January 2025
Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; The Research Center of Chiral Drugs, Shanghai Frontiers Science Center for TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. Electronic address:
Chiral azacyclic amine derivatives occupy a vital role of nitrogen-containing compounds, due to serve as foundational motifs in numerous pharmaceuticals and bioactive substances. Novel complementary enantioselective reductive aminases IRED9 and IRED11 were unveiled through comprehensive gene mining from Streptomyces viridochromogenes and Micromonospora echinaurantiaca, respectively, which both demonstrated enantiomeric excess (ee) values and conversion ratio up to 99% towards N-Boc-3-pyridinone (NBPO) and cyclopropylamine. IRED9 exhibited the highest activity at pH 8.
View Article and Find Full Text PDFLangmuir
January 2025
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe, Mizuho, Nagoya 467-8603, Aichi, Japan.
In this study, we demonstrate a novel and efficient fabrication methodology for nonclose-packed, two-dimensional (2D) colloidal crystals exhibiting square lattice structures. In our recent work, we detailed the formation of 2D colloidal crystals via the electrostatic adsorption of three-dimensional (3D) charged colloidal crystals onto oppositely charged substrates. These 3D colloidal crystals possessed a face-centered cubic (FCC) lattice structure with their (111) planes aligned parallel to the substrate, facilitating the formation of 2D crystals with triangular lattice arrangements upon adsorption.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Instituto de Física, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, MG, Brazil.
Charge layering in the close vicinity of charged interfaces is a well-known effect, extensively reported in both experiments and simulations of Room Temperature Ionic Liquids (RTILs) and concentrated electrolytes. The traditional Poisson-Fermi (PF) theory is able to successfully describe overcrowding effects but fails to reproduce charge ordering even in strong coupling regimes. Simple models, yet capable of investigating the interplay between these important interfacial phenomena, are still lacking.
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