Search results for "Planar"
showing 10 items of 412 documents
Tractional Motion Machines: Tangent-Managing Planar Mechanisms as Analog Computers and Educational Artifacts
2012
Concrete and virtual machines play a central role in the both Unconventional Computing (machines as computers) and in Math Education (influence of artifacts on reaching/producing abstract thought). Here we will examine some fallouts in these fields for the Tractional Motion Machines, planar mechanisms based on some devices used to plot the solutions of differential equations by the management of the tangent since the late 17th century.
Graphene nanoribbons subject to gentle bends
2012
Since graphene nanoribbons are thin and flimsy, they need support. Support gives firm ground for applications, and adhesion holds ribbons flat, although not necessarily straight: ribbons with high aspect ratio are prone to bend. The effects of bending on ribbons' electronic properties, however, are unknown. Therefore, this article examines the electromechanics of planar and gently bent graphene nanoribbons. Simulations with density-functional tight-binding and revised periodic boundary conditions show that gentle bends in armchair ribbons can cause significant widening or narrowing of energy gaps. Moreover, in zigzag ribbons sizeable energy gaps can be opened due to axial symmetry breaking,…
Molecular-dynamics computer simulation of crystal growth and melting in Al 50 Ni 50
2008
The melting and crystallization of Al50Ni50} are studied by means of molecular dynamics computer simulations, using a potential of the embedded atom type to model the interactions between the particles. Systems in a slab geometry are simulated where the B2 phase of AlNi in the middle of an elongated simulation box is separated by two planar interfaces from the liquid phase, thereby considering the (100) crystal orientation. By determining the temperature dependence of the interface velocity, an accurate estimate of the melting temperature is provided. The value k=0.0025 m/s/K for the kinetic growth coefficient is found. This value is about two orders of magnitude smaller than that found in …
Influence of the excitation conditions on the emission behavior of carbon nanodot-based planar microcavities
2020
The authors investigate the influence of the pulse length as well as the repetition rate of the optical excitation on the emission behavior of carbon-nanodot-based planar microcavities.
Wide-range thermometer based on the temperature-dependent conductance of planar tunnel junctions
2000
The effect of the Fermi–Dirac distribution on the current through standard planar tunnel junctions is a suitable basis for thermometry in a wide temperature range. In particular, it extends the range spanned by Coulomb-blockade thermometers up to room temperature.
Theoretical modeling of Langmuir monolayers
1999
Abstract We study coarse-grained continuum models for Langmuir monolayers by self-consistent field theory and by Monte Carlo simulations. Amphiphilic molecules are represented by stiff chains of monomers with one end grafted to a planar surface. In particular, we discuss the origin of successive fluid–fluid transitions, the possible origin of tilt order and the factors which determine the direction of tilt.
Monte Carlo Simulation of Langmuir Monolayer Models
1998
We study a coarse grained, continuum model for Langmuir monolayers, i.e., monolayers of amphiphilic molecules on a polar substrate. The amphiphiles are represented by stiff chains of beads with one end grafted to a planar surface. Monte Carlo Simulations at constant pressure have been performed, using simulation boxes of variable size and variable shape. A number of techniques have been explored in order to obtain an efficient simulation algorithm. We discuss the resulting phase diagram, characterize the different phases, and analyze the conditions, under which they can be found.
A New Colloid Model for Dissipative-Particle-Dynamics Simulations
2016
We propose a new model to simulate spherical colloids. This is a mesoscopic method based on the dissipative particle dynamics. The colloid is represented by a large spherical bead, and its surface interacts with the solvent beads through a pair of dissipative and stochastic forces. This new model extends the tunable-slip boundary condition [Eur. Phys. J. E 26, 115 (2008)] from planar surfaces to curved geometry, thus allows one to study colloids with slippery surfaces. Simulation results show good agreement with the prediction of hydrodynamic theories, indicating the hydrodynamic interactions are properly accounted in our new model.
A stable oxoverdazyl free radical: Structural and magnetic characterization
2006
Abstract The structure and magnetic properties (susceptibility and ESR) of the stable oxoverdazyl free radical 6-(4-acetamidophenyl)-1,4,5,6-tetrahydro-2,4-dimethyl-1,2,4,5-tetrazin-3(2H)-one are presented. The crystal structure consists of chains of parallel planar molecules running along the b-axis. These chains are formed by dimers with a ring-over-bond overlap and a significant offset between dimers, although with similar inter- and intradimer distances. The susceptibility measurements show that this compound is an S = 1/2 paramagnet with weak antiferromagnetic interactions. The magnetic susceptibility can be very well reproduced with an antiferromagnetic regular chain model with g = 2.…
Influence of device geometry on sensor characteristics of planar organic electrochemical transistors.
2009
The response of PEDOT:PSS planar electrochemical transistors to H2O2 can be tuned by varying the ratio between the areas of the channel and the gate electrode. Devices with small gates show lower background signal and higher sensitivity. The detection range, on the other hand, is found to be rather independent of the gate/channel area ratio.