4,193 research outputs found
The Strawberry Growth Underneath the Nettle: the emergence of entrepreneurs in China
Chinese entrepreneurs innovatively manage organisations in the absence of strong economic institutions, under conditions of high environmental and technological uncertainty. This paper presents the findings of an empirical study designed to investigate how Chinese entrepreneurs can be successful in such an environment. We found that Chinese entrepreneurial activity relies on social institutions rather than on economic institutions. We offer a sociological theory which explains why the reliance on social institutions leads to such an unprecedented success. We conclude that the strong rule-enforcement mechanisms generate reliable behavioral patterns, and that these in turn efficiently reduce uncertainty to tolerable levels.networks;social capital;evolutionary economics;Comparative business systems;private sector in China
Drift causes anomalous exponents in growth processes
The effect of a drift term in the presence of fixed boundaries is studied for
the one-dimensional Edwards-Wilkinson equation, to reveal a general mechanism
that causes a change of exponents for a very broad class of growth processes.
This mechanism represents a relevant perturbation and therefore is important
for the interpretation of experimental and numerical results. In effect, the
mechanism leads to the roughness exponent assuming the same value as the growth
exponent. In the case of the Edwards-Wilkinson equation this implies exponents
deviating from those expected by dimensional analysis.Comment: 4 pages, 1 figure, REVTeX; accepted for publication in PRL; added
note and reference
Damping of Oscillations in Layer-by-Layer Growth
We present a theory for the damping of layer-by-layer growth oscillations in
molecular beam epitaxy. The surface becomes rough on distances larger than a
layer coherence length which is substantially larger than the diffusion length.
The damping time can be calculated by a comparison of the competing roughening
and smoothening mechanisms. The dependence on the growth conditions,
temperature and deposition rate, is characterized by a power law. The
theoretical results are confirmed by computer simulations.Comment: 19 pages, RevTex, 5 Postscript figures, needs psfig.st
Morphological stability of electromigration-driven vacancy islands
The electromigration-induced shape evolution of two-dimensional vacancy
islands on a crystal surface is studied using a continuum approach. We consider
the regime where mass transport is restricted to terrace diffusion in the
interior of the island. In the limit of fast attachment/detachment kinetics a
circle translating at constant velocity is a stationary solution of the
problem. In contrast to earlier work [O. Pierre-Louis and T.L. Einstein, Phys.
Rev. B 62, 13697 (2000)] we show that the circular solution remains linearly
stable for arbitrarily large driving forces. The numerical solution of the full
nonlinear problem nevertheless reveals a fingering instability at the trailing
end of the island, which develops from finite amplitude perturbations and
eventually leads to pinch-off. Relaxing the condition of instantaneous
attachment/detachment kinetics, we obtain non-circular elongated stationary
shapes in an analytic approximation which compares favorably to the full
numerical solution.Comment: 12 page
Interfaces with a single growth inhomogeneity and anchored boundaries
The dynamics of a one dimensional growth model involving attachment and
detachment of particles is studied in the presence of a localized growth
inhomogeneity along with anchored boundary conditions. At large times, the
latter enforce an equilibrium stationary regime which allows for an exact
calculation of roughening exponents. The stochastic evolution is related to a
spin Hamiltonian whose spectrum gap embodies the dynamic scaling exponent of
late stages. For vanishing gaps the interface can exhibit a slow morphological
transition followed by a change of scaling regimes which are studied
numerically. Instead, a faceting dynamics arises for gapful situations.Comment: REVTeX, 11 pages, 9 Postscript figure
An Exactly Solved Model of Three Dimensional Surface Growth in the Anisotropic KPZ Regime
We generalize the surface growth model of Gates and Westcott to arbitrary
inclination. The exact steady growth velocity is of saddle type with principal
curvatures of opposite sign. According to Wolf this implies logarithmic height
correlations, which we prove by mapping the steady state of the surface to
world lines of free fermions with chiral boundary conditions.Comment: 9 pages, REVTEX, epsf, 3 postscript figures, submitted to J. Stat.
Phys, a wrong character is corrected in eqs. (31) and (32
Magnetic coupling in highly-ordered NiO/Fe3O4(110): Ultrasharp magnetic interfaces vs. long-range magnetoelastic interactions
We present a laterally resolved X-ray magnetic dichroism study of the
magnetic proximity effect in a highly ordered oxide system, i.e. NiO films on
Fe3O4(110). We found that the magnetic interface shows an ultrasharp
electronic, magnetic and structural transition from the ferrimagnet to the
antiferromagnet. The monolayer which forms the interface reconstructs to
NiFe2O4 and exhibits an enhanced Fe and Ni orbital moment, possibly caused by
bonding anisotropy or electronic interaction between Fe and Ni cations. The
absence of spin-flop coupling for this crystallographic orientation can be
explained by a structurally uncompensated interface and additional
magnetoelastic effects
Phenomenology of ageing in the Kardar-Parisi-Zhang equation
We study ageing during surface growth processes described by the
one-dimensional Kardar-Parisi-Zhang equation. Starting from a flat initial
state, the systems undergo simple ageing in both correlators and linear
responses and its dynamical scaling is characterised by the ageing exponents
a=-1/3, b=-2/3, lambda_C=lambda_R=1 and z=3/2. The form of the autoresponse
scaling function is well described by the recently constructed logarithmic
extension of local scale-invariance.Comment: Latex2e, 5 pages, with 4 figures, final for
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