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561.
Torben Jasper-Tönnies Dr. Manuel Gruber Dr. Sandra Ulrich Prof. Dr. Rainer Herges Prof. Dr. Richard Berndt 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(18):7074-7083
The competition between honeycomb and hexagonal tiling of molecular units can lead to large honeycomb superstructures on surfaces. Such superstructures exhibit pores that may be used as 2D templates for functional guest molecules. Honeycomb superstructures of molecules that comprise a C3 symmetric platform on Au(111) and Ag(111) surfaces are presented. The superstructures cover nearly mesoscopic areas with unit cells containing up to 3000 molecules, more than an order of magnitude larger than previously reported. The unit cell size may be controlled by the coverage. A fairly general model was developed to describe the energetics of honeycomb superstructures built from C3 symmetric units. Based on three parameters that characterize two competing bonding arrangements, the model is consistent with the present experimental data and also reproduces various published results. The model identifies the relevant driving force, mostly related to geometric aspects, of the pattern formation. 相似文献
562.
Markus Berndt Jérôme Breil Stéphane Galera Milan Kucharik Pierre-Henri Maire Mikhail Shashkov 《Journal of computational physics》2011,230(17):6664-6687
We present a new hybrid conservative remapping algorithm for multimaterial Arbitrary Lagrangian–Eulerian (ALE) methods. The hybrid remapping is performed in two steps. In the first step, only nodes of the grid that lie inside subdomains occupied by single materials are moved. At this stage, computationally cheap swept-region remapping is used. In the second step, nodes that are vertices of mixed cells (cells containing several materials) and vertices of some cells in a buffer zone around mixed cells are moved. At this stage, intersection-based remapping is used. The hybrid algorithm results in computational expense that lies between swept-region and intersection-based remapping We demonstrate the performance of our new method for both structured and unstructured polygonal grids in two dimensions, as well as for cell-centered and staggered discretizations. 相似文献
563.
This is a brief review of the theory and phenomenology of parton energy loss in strongly coupled field theories with a gravity dual and its comparison with parton energy loss in QCD at weak coupling. 相似文献
564.
Lead phthalocyanine (PbPc) deposited on lead islands on Ag(111) forms two-dimensional crystals of densely packed molecules. For particular orientations, the molecular arrays exhibit an electronic superstructure with an extraordinarily large unit cell. The molecules induce a shift of quantum well states, which are confined to the Pb islands. Patterns formed by PbPc on Ag(111) are drastically different. 相似文献
565.
Sabrina Berndt Falko Wesarg Cornelia Wiegand Dana Kralisch Frank A. Müller 《Cellulose (London, England)》2013,20(2):771-783
The increasing resistance of pathogens and bacteria is a serious problem in the medical treatment of wounds and injuries. Therefore, new therapeutic agents are not solely based on antibiotics, but also on the use of antimicrobial metal nanoparticles. In this paper we present an innovative method to prepare porous hybrids consisting of bacterial nanocellulose (BNC) and silver nanoparticles (AgNPs). The stepwise modification is based on fairly simple chemical reactions already described for two-dimensional cellulose films. We transferred this method to the three-dimensional, porous network of BNC leading to an antimicrobial activation of its surface. Compared to former approaches, the ultrafine network structure of BNC is less damaged by using mild chemicals. The amount and distribution of the AgNPs on the modified BNC was investigated using scanning electron microscopy. The AgNPs are firmly immobilized on the top and bottom surface of the BNC by chemical interactions. Their size and quantity increase with an increasing concentration of AgNO3 and extended reaction time in the AgNO3 solution. A strong antimicrobial activity of the BNC-AgNP hybrids against Escherichia coli was detected. Furthermore, agar diffusion tests confirmed that this activity is restricted to the modified dressing itself, avoiding a release of NPs into the wound. Therefore, the produced hybrids could be potentially suited as novel antimicrobial wound dressings. 相似文献
566.
Variations of the spectra of plasmonic light emitted from the junction of a scanning tunneling microscope have been observed for different lateral positions of the scanning tunneling microscope tip on a Au(111) surface. Subnanometer spatial variations of the light emission intensity over a triangular island and in the vicinity of surface step edges have been recorded at different photon energies. They reveal surface standing wave patterns characteristic for two-dimensional confined electrons. 相似文献
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