4,046 research outputs found
Spin Correlations in top quark pair production near threshold at the Linear Collider
We investigate the spin correlations in top quark pair production near
threshold at the linear collider. Comparing with the results above
the threshold region, we find that near the threshold region the off-diagonal
basis, the optimized decomposition of the top quark spins above the threshold
region, does not exist, and the beamline basis is the optimal basis, in which
there are the dominant spin components: the up-down (UD) component for scattering and the down-up (DU) component for scattering can
make up more than 50% of the total cross section, respectively.Comment: 12 pages, 3 figures, minor modification
Can pro-environmental behavior increase farmersâ income?âEvidence from arable land quality protection practices in China
In China, agricultural non-point source pollution is one of the key
factors limiting farmersâ income growth, and pro-environmental
behavior can address agricultural surface pollution. Based on field
survey data from 591 farmers in Xinjiang, China, this study empirically
estimates the impact of pro-environmental behavior on
farmersâ income growth. The results show that pro-environmental
behavior plays a significant positive role in increasing farmersâ
income, and the positive effect continues in the long run.
Specifically, pro-environmental behavior can optimize the allocation
of agricultural production factors, thus resulting in farmersâ
income growth. The mechanism analysis shows that pro-environmental
behavior affects farmersâ income growth by promoting
the increase in the size of arable land and farmersâ willingness to
transfer their land in the future. These findings indicate that a
sound rewardâpunishment system for pro-environmental behavior
should be established; training on pro-environmental behavior
should be strengthened, and a mechanism for linking the benefits
of pro-environmental behavior among stakeholders should be
constructed
Monte Carlo Hamiltonian: the Linear Potentials
We further study the validity of the Monte Carlo Hamiltonian method. The
advantage of the method, in comparison with the standard Monte Carlo Lagrangian
approach, is its capability to study the excited states. We consider two
quantum mechanical models: a symmetric one ; and an asymmetric
one , for and , for . The results for the
spectrum, wave functions and thermodynamical observables are in agreement with
the analytical or Runge-Kutta calculations.Comment: Latex file, 8 figure
Ultrafast fluorescent decay induced by metal-mediated dipole-dipole interaction in two-dimensional molecular aggregates
Two-dimensional molecular aggregate (2DMA), a thin sheet of strongly
interacting dipole molecules self-assembled at close distance on an ordered
lattice, is a fascinating fluorescent material. It is distinctively different
from the single or colloidal dye molecules or quantum dots in most previous
research. In this paper, we verify for the first time that when a 2DMA is
placed at a nanometric distance from a metallic substrate, the strong and
coherent interaction between the dipoles inside the 2DMA dominates its
fluorescent decay at picosecond timescale. Our streak-camera lifetime
measurement and interacting lattice-dipole calculation reveal that the
metal-mediated dipole-dipole interaction shortens the fluorescent lifetime to
about one half and increases the energy dissipation rate by ten times than
expected from the noninteracting single-dipole picture. Our finding can enrich
our understanding of nanoscale energy transfer in molecular excitonic systems
and may designate a new direction for developing fast and efficient
optoelectronic devices.Comment: 9 pages, 6 figure
THE RESEARCH INTO RELATIVE HEIGHT OF TOTAL BODY CENTER OF GRAVITY OF MALES AND FEMALES AGED 17 -20 YEARS
By measuring the body center of gravity of 939 males and females aged 17-20 years in urban and rural areas when they stand at attention and hold up arms lathered, we found out the height and positions of the total center of gravity of them who were in different heights. It has great practical values to research the effect of body forms to the sports ability and also has great values to the selection of the sportsmen and technical analysis
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