5,031 research outputs found
A 12-fold ths interpenetrated network utilizing a glycine-based pseudopeptidic ligand
We report the synthesis and characterization of a 3D Cu(II) coordination polymer, [Cu3(L1)2(H2O)8]·8H2O (1), with the use of a glycine-based tripodal pseudopeptidic ligand (H3L1 = N,N’,N’’-tris(carboxymethyl)-1,3,5-benzenetricarboxamide or trimesoyl-tris-glycine). This compound presents the first example of a 12-fold interpenetrated ths net. We attempt to justify the unique topology of 1 through a systematic comparison of the synthetic parameters in all reported structures with H3L1 and similar tripodal pseudopeptidic ligands. We additionally explore the catalytic potential of 1 in the A3 coupling reaction for the synthesis of propargylamines. The compound acts as a very good heterogeneous catalyst with yields up to 99% and loadings as low as 3 mol%
Scalar-tensor black holes coupled to Born-Infeld nonlinear electrodynamics
The non-existence of asymptotically flat, neutral black holes and
asymptotically flat, charged black holes in the Maxwell electrodynamics, with
non-trivial scalar field has been proved for a large class of scalar-tensor
theories. The no-scalar-hair theorems, however, do not apply in the case of
non-linear electrodynamics. In the present work numerical solutions describing
charged black holes coupled to Born-Infeld type non-linear electrodynamics in
scalar-tensor theories of gravity with massless scalar field are found. The
causal structure and properties of the solutions are studied, and a comparison
between these solutions and the corresponding solutions in the General
Relativity is made. The presence of the scalar field leads to a much more
simple causal structure. The present class of black holes has a single,
non-degenerate horizon, i.e., its causal structure resembles that of the
Schwarzschild black hole.Comment: 12 pages, 4 figures, PR
A mesoscopic model for microscale hydrodynamics and interfacial phenomena: Slip, films, and contact angle hysteresis
We present a model based on the lattice Boltzmann equation that is suitable
for the simulation of dynamic wetting. The model is capable of exhibiting
fundamental interfacial phenomena such as weak adsorption of fluid on the solid
substrate and the presence of a thin surface film within which a disjoining
pressure acts. Dynamics in this surface film, tightly coupled with
hydrodynamics in the fluid bulk, determine macroscopic properties of primary
interest: the hydrodynamic slip; the equilibrium contact angle; and the static
and dynamic hysteresis of the contact angles. The pseudo- potentials employed
for fluid-solid interactions are composed of a repulsive core and an attractive
tail that can be independently adjusted. This enables effective modification of
the functional form of the disjoining pressure so that one can vary the static
and dynamic hysteresis on surfaces that exhibit the same equilibrium contact
angle. The modeled solid-fluid interface is diffuse, represented by a wall
probability function which ultimately controls the momentum exchange between
solid and fluid phases. This approach allows us to effectively vary the slip
length for a given wettability (i.e. the static contact angle) of the solid
substrate
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