437 research outputs found
Odd Fibbinary Numbers and the Golden Ratio
The fibbinary numbers are positive integers whose binary representation contains no consecutive ones. We prove the following result: If the jth odd fibbinary is the nth odd fibbinary number, then j={nɸ2]-1
Controlled formation of Schottky diodes on n-doped ZnO layers by deposition of p-conductive polymer layers with oxidative chemical vapor deposition
We report the controlled formation of organic/inorganic Schottky diodes by depositing poly(3,4-
ethylenedioxythiophene) (PEDOT) on n-doped ZnO layers using oxidative chemical vapor deposition
(oCVD). Current-voltage measurements reveal the formation of Schottky diodes that show good
thermal and temporal stability with rectification ratios of 10 7 and ideality factors of ∼1.2. In the frame
of a Schottky model, we identify a mean barrier height at the hybrid inorganic-organic interface of
1.28 eV, which is consistent with the difference between the work function of PEDOT and the electron
affinity of ZnO. The findings highlight the strength of oCVD to design high-quality hybrid PEDOT/
ZnO heterojunctions with possible applications in electronic and optoelectronic devices
A Side-Channel Attack on a Hardware Implementation of CRYSTALS-Kyber
CRYSTALS-Kyber has been recently selected by the NIST as a new public-key encryption and key-establishment algorithm to be standardized. This makes it important to assess how well CRYSTALS-Kyber implementations withstand side-channel attacks. Software implementations of CRYSTALS-Kyber have been already analyzed and the discovered vulnerabilities were patched in the subsequently released versions. In this paper, we present a profiling side-channel attack on a hardware implementation of CRYSTALS-Kyber with the security parameter , Kyber768. Since hardware implementations carry out computation in parallel, they are typically more difficult to break than their software counterparts. We demonstrate a successful message (session key) recovery by deep learning-based power analysis. Our results indicate that currently available hardware implementations of CRYSTALS-Kyber need better protection against side-channel attacks
Incommensurate charge-stripe correlations in the kagome superconductor CsVSbSn
We track the evolution of charge correlations in the kagome superconductor
CsVSb as its parent, long-ranged charge density order is destabilized.
Upon hole-doping doping, interlayer charge correlations rapidly become
short-ranged and their periodicity is reduced by half along the interlayer
direction. Beyond the peak of the first superconducting dome, the parent charge
density wave state vanishes and incommensurate, quasi-1D charge correlations
are stabilized in its place. These competing, unidirectional charge
correlations demonstrate an inherent electronic rotational symmetry breaking in
CsVSb, independent of the parent charge density wave state and reveal a
complex landscape of charge correlations across the electronic phase diagram of
this class of kagome superconductors. Our data suggest an inherent 2
charge instability and the phenomenology of competing charge instabilities is
reminiscent of what has been noted across several classes of unconventional
superconductors.Comment: 6 pages, 4 figure
Resonant excitation of plasma waves in a plasma channel
We demonstrate resonant excitation of a plasma wave by a train of short laser pulses guided in a preformed plasma channel, for parameters relevant to a plasma-modulated plasma accelerator (P-MoPA). We show experimentally that a train of N≈10 short pulses, of total energy ∼1J, can be guided through 110mm long plasma channels with on-axis densities in the range 1017-1018cm-3. The spectrum of the transmitted train is found to be strongly red shifted when the plasma period is tuned to the intratrain pulse spacing. Numerical simulations are found to be in excellent agreement with the measurements and indicate that the resonantly excited plasma waves have an amplitude in the range 3-10GVm-1, corresponding to an accelerator stage energy gain of order 1GeV
Topology by Design in Magnetic nano-Materials: Artificial Spin Ice
Artificial Spin Ices are two dimensional arrays of magnetic, interacting
nano-structures whose geometry can be chosen at will, and whose elementary
degrees of freedom can be characterized directly. They were introduced at first
to study frustration in a controllable setting, to mimic the behavior of spin
ice rare earth pyrochlores, but at more useful temperature and field ranges and
with direct characterization, and to provide practical implementation to
celebrated, exactly solvable models of statistical mechanics previously devised
to gain an understanding of degenerate ensembles with residual entropy. With
the evolution of nano--fabrication and of experimental protocols it is now
possible to characterize the material in real-time, real-space, and to realize
virtually any geometry, for direct control over the collective dynamics. This
has recently opened a path toward the deliberate design of novel, exotic
states, not found in natural materials, and often characterized by topological
properties. Without any pretense of exhaustiveness, we will provide an
introduction to the material, the early works, and then, by reporting on more
recent results, we will proceed to describe the new direction, which includes
the design of desired topological states and their implications to kinetics.Comment: 29 pages, 13 figures, 116 references, Book Chapte
Animal-related factors associated with moderate-to-severe diarrhea in children younger than five years in western Kenya: A matched case-control study
Background Diarrheal disease remains among the leading causes of global mortality in children younger than 5 years. Exposure to domestic animals may be a risk factor for diarrheal disease. The objectives of this study were to identify animal-related exposures associated with cases of moderate-to-severe diarrhea (MSD) in children in rural western Kenya, and to identify the major zoonotic enteric pathogens present in domestic animals residing in the homesteads of case and control children. Methodology/Principal findings We characterized animal-related exposures in a subset of case and control children (n = 73 pairs matched on age, sex and location) with reported animal presence at home enrolled in the Global Enteric Multicenter Study in western Kenya, and analysed these for an association with MSD. We identified potentially zoonotic enteric pathogens in pooled fecal specimens collected from domestic animals resident at children’s homesteads. Variables that were associated with decreased risk of MSD were washing hands after animal contact (matched odds ratio [MOR] = 0.2; 95% CI 0.08–0.7), and presence of adult sheep that were not confined in a pen overnight (MOR = 0.1; 0.02–0.5). Variables that were associated with increased risk of MSD were increasing number of sheep owned (MOR = 1.2; 1.0–1.5), frequent observation of fresh rodent excreta (feces/urine) outside the house (MOR = 7.5; 1.5–37.2), and participation of the child in providing water to chickens (MOR = 3.8; 1.2–12.2). Of 691 pooled specimens collected from 2,174 domestic animals, 159 pools (23%) tested positive for one or more potentially zoonotic enteric pathogens (Campylobacter jejuni, C. coli, non-typhoidal Salmonella, diarrheagenic E. coli, Giardia, Cryptosporidium, or rotavirus). We did not find any association between the presence of particular pathogens in household animals, and MSD in children. Conclusions and significance Public health agencies should continue to promote frequent hand washing, including after animal contact, to reduce the risk of MSD. Future studies should address specific causal relations of MSD with sheep and chicken husbandry practices, and with the presence of rodents
Acoustics and oceanographic observations collected during the QPE Experiment by Research Vessels OR1, OR2 and OR3 in the East China Sea in the Summer of 2009
This document describes data, sensors, and other useful information pertaining to the ONR sponsored
QPE field program to quantify, predict and exploit uncertainty in observations and prediction of sound
propagation. This experiment was a joint operation between Taiwanese and U.S. researchers to
measure and assess uncertainty of predictions of acoustic transmission loss and ambient noise, and to
observe the physical oceanography and geology that are necessary to improve their predictability. This
work was performed over the continental shelf and slope northeast of Taiwan at two sites: one that was
a relatively flat, homogeneous shelf region and a more complex geological site just shoreward of the
shelfbreak that was influenced by the proximity of the Kuroshio Current. Environmental moorings
and ADCP moorings were deployed and a shipboard SeaSoar vehicle was used to measure
environmental spatial structure. In addition, multiple bottom moored receivers and a horizontal
hydrophone array were deployed to sample transmission loss from a mobile source and ambient noise.
The acoustic sensors, environmental sensors, shipboard resources, and experiment design, and their
data, are presented and described in this technical report.Funding was provided by the Office of Naval Research under Contract No. N00014-08-1-076
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