6,413 research outputs found
Wearable, small, and robust: the circular quarter-mode textile antenna
A miniaturized wearable antenna, entirely implemented in textile materials, is proposed that relies on a quarter-mode substrate integrated waveguide topology. The design combines compact dimensions with high body-antenna isolation, making it excellently suited for off-body communication in wearable electronics/smart textile applications. The fabricated antenna achieves stable on-body performance. A measured on-body impedance matching bandwidth of 5.1% is obtained, versus 4.8% in free space. The antenna gain equals 3.8 dBi in the on-body and 4.2 dBi for the free-space scenario. High radiation efficiency, measured to be 81% in free space, is combined with a low calculated specific absorption rate of 0.45 mW/g, averaged over 1 g of tissue, with 500 mW input power
Resonating Valence Bond Quantum Monte Carlo: Application to the ozone molecule
We study the potential energy surface of the ozone molecule by means of
Quantum Monte Carlo simulations based on the resonating valence bond concept.
The trial wave function consists of an antisymmetrized geminal power arranged
in a single-determinant that is multiplied by a Jastrow correlation factor.
Whereas the determinantal part incorporates static correlation effects, the
augmented real-space correlation factor accounts for the dynamics electron
correlation. The accuracy of this approach is demonstrated by computing the
potential energy surface for the ozone molecule in three vibrational states:
symmetric, asymmetric and scissoring. We find that the employed wave function
provides a detailed description of rather strongly-correlated multi-reference
systems, which is in quantitative agreement with experiment.Comment: 5 page, 3 figure
Root system chip-firing II: Central-firing
Jim Propp recently proposed a labeled version of chip-firing on a line and
conjectured that this process is confluent from some initial configurations.
This was proved by Hopkins-McConville-Propp. We reinterpret Propp's labeled
chip-firing moves in terms of root systems: a "central-firing" move consists of
replacing a weight by for any positive root
that is orthogonal to . We show that central-firing is always
confluent from any initial weight after modding out by the Weyl group, giving a
generalization of unlabeled chip-firing on a line to other types. For
simply-laced root systems we describe this unlabeled chip-firing as a number
game on the Dynkin diagram. We also offer a conjectural classification of when
central-firing is confluent from the origin or a fundamental weight.Comment: 30 pages, 6 figures, 1 table; v2, v3: minor revision
Root system chip-firing I: Interval-firing
Jim Propp recently introduced a variant of chip-firing on a line where the
chips are given distinct integer labels. Hopkins, McConville, and Propp showed
that this process is confluent from some (but not all) initial configurations
of chips. We recast their set-up in terms of root systems: labeled chip-firing
can be seen as a root-firing process which allows the moves for whenever
, where is the set of
positive roots of a root system of Type A and is a weight of this
root system. We are thus motivated to study the exact same root-firing process
for an arbitrary root system. Actually, this central root-firing process is the
subject of a sequel to this paper. In the present paper, we instead study the
interval root-firing processes determined by for
whenever or , for any . We prove that these interval-firing processes are always confluent,
from any initial weight. We also show that there is a natural way to
consistently label the stable points of these interval-firing processes across
all values of so that the number of weights with given stabilization is a
polynomial in . We conjecture that these Ehrhart-like polynomials have
nonnegative integer coefficients.Comment: 54 pages, 12 figures, 2 tables; v2: major revisions to improve
exposition; v3: to appear in Mathematische Zeitschrift (Math. Z.
Attention, Work and Well-Being. What Happens When We Pay Attention to the Work We Are Doing?
SJU alum Dr. Sam Thomas shared his thoughts on Attention, Work and Well-Being. What happens when we pay attention to the work we are doing? He explored some of the connections between work, craft and spirituality and their importance for both personal fulfillment and community life
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