Search results for "layer"
showing 10 items of 2667 documents
Phospholipid and phospholipid-protein monolayers at the air/water interface.
1990
Influence of chirality on the structure of phospholipid monolayers.
1993
Modelling of Orientational Ordering in Lipid Monolayers
1993
Lipid monolayers at high densities are modelled as rigid rods grafted to an interface at the sites of a regular lattice. The transition between the state where the rods are uniformly tilted to a disordered state with no (average) tilt is studied by computer simulation methods. For the one-dimensional model, the molecular dynamics approach is found much less suitable to equilibrate the system rather than Monte Carlo methods. Both in d=2 discretized versions of Monte Carlo codes are much more efficient than continuum Monte Carlo methods, in spite of huge storage requirements. While in d=l the transition occurs at temperature T=0 via the spontaneous creation of solitons, at d=2 a finite temper…
ChemInform Abstract: Hybrid Materials Based on Magnetic Layered Double Hydroxides: A Molecular Perspective
2015
ConspectusDesign of functional hybrids lies at the very core of synthetic chemistry as it has enabled the development of an unlimited number of solids displaying unprecedented or even improved properties built upon the association at the molecular level of quite disparate components by chemical design. Multifunctional hybrids are a particularly appealing case among hybrid organic/inorganic materials. Here, chemical knowledge is used to deploy molecular components bearing different functionalities within a single solid so that these properties can coexist or event interact leading to unprecedented phenomena. From a molecular perspective, this can be done either by controlled assembly of orga…
Cooperative Effects Enhance Electric-Field-Induced Conductance Switching in Molecular Monolayers
2011
The anchoring of molecules with functional groups at surfaces permits information processing based on two stable molecular states that can be tuned externally by light irradiation and external fields. By using a molecular model that incorporates the essential characteristics of the problem, we show that the local interactions between adjacent molecules in a densely packed monolayer can stabilize domains with the same molecular state because of cooperative processes, enhancing significantly the switching properties between the molecular states. The case of electric-field-induced conductance switching is exploited in two possible applications: the design of a logic gates system and the operat…
Electroburning of few-layer graphene flakes, epitaxial graphene, and turbostratic graphene discs in air and under vacuum
2015
Graphene-based electrodes are very promising for molecular electronics and spintronics. Here we report a systematic characterization of the electroburning (EB) process, leading to the formation of nanometer-spaced gaps, on different types of few-layer graphene (namely mechanically exfoliated graphene on SiO2, graphene epitaxially grown on the C-face of SiC and turbostratic graphene discs deposited on SiO2) under air and vacuum conditions. The EB process is found to depend on both the graphene type and on the ambient conditions. For the mechanically exfoliated graphene, performing EB under vacuum leads to a higher yield of nanometer-gap formation than working in air. Conversely, for graphene…
Molybdenum thin film growth on a TiO2 (1 1 0) substrate.
2009
International audience; We report a first principles study on the structure and energetics of thin films of molybdenum on a (1 1 0) surface of rutile TiO2. Mo films with 1 × 1 epitaxy in the coverage range between 0.5 and 2 monolayer are investigated. The most stable structures are those which maximize the number of Mo–Mo bonds. This leads to two-dimensional structures with zigzag Mo–Mo coordination for 1 monolayer coverage and three-dimensional structures with approximately body-centered cubic coordination for higher coverage. For a coverage up to 1.5 monolayers, the interface Mo atoms preferentially occupy the so-called upper hollow adsorption site with three Mo–O bonds
Morphology Study of the Porosity of the GaP Surface Layer Formed on the Surface of a Single Crystal by Electrochemical Etching
2021
The article analyzes the morphological characteristics of a porous GaP surface layer formed on the surface of monocrystalline gallium phosphide by electrochemical etching. The correlations between the etching time and the appropriate size, shape and density of pores have been established and studied in detail.
New Alkaloids of the Sarpagine Group from Rauvolfia serpentina Hairy Root Culture
2002
Three new monoterpenoid indole alkaloids, 19(S),20(R)-dihydroperaksine (1), 19(S),20(R)-dihydroperaksine-17-al (2), and 10-hydroxy-19(S),20(R)-dihydroperaksine (3), along with 16 known alkaloids 4-19 were isolated from hairy root culture of Rauvolfia serpentina, and their structures were elucidated by 1D and 2D NMR analyses. Taking into account the stereochemistry of the new alkaloids and results of preliminary enzymatical studies, the putative biosynthetical relationships between the novel alkaloids are discussed.