9,736 research outputs found
Magnetic Properties of the Novel Low-Dimensional Cuprate Na5RbCu4(AsO4)4Cl2
The magnetic properties of a new compound, Na5RbCu4(AsO4)4Cl2 are reported.
The material has a layered structure comprised of square Cu4O4 tetramers. The
Cu ions are divalent and the system behaves as a low-dimensional S=1/2
antiferromagnet. Spin exchange in Na5RbCu4(AsO4)4Cl2 appears to be
quasi-two-dimensional and non-frustrated. Measurements of the bulk magnetic
susceptibility and heat capacity are consistent with low-dimensional magnetism.
The compound has an interesting, low-entropy, magnetic transition at T = 17 K.Comment: 4 pages, 5 figure
U.S.-CANADA BORDER DISPUTES IN GRAINS: DYNAMIC INTERFACE BETWEEN THE FREE TRADE AGREEMENT AND TRADE REMEDY LAWS
Agricultural trade between the United States and Canada has been contentious since the inception of the CUSTA agreement in 1989. Even though Canadian exports of wheat and barley are not found to have violated U.S. trade remedy laws, friction seems likely to continue as long as the surge in Canadian exports remains unabated. Gradual harmonization of trade policies, farm subsidy programs, and marketing institutions may reduce trade disputes between the two countries in the future. To diffuse the threat of future trade disputes, a Canada - U.S. joint research team should be formed to deal with the matter through better understanding for causes of the disputes.bilateral trade, free trade agreement, trade disputes, trade remedy laws, farm income, farm price, harmonization, International Relations/Trade,
Resonant x-ray scattering study on multiferroic BiMnO3
Resonant x-ray scattering is performed near the Mn K-absorption edge for an
epitaxial thin film of BiMnO3. The azimuthal angle dependence of the resonant
(003) peak (in monoclinic indices) is measured with different photon
polarizations; for the channel a 3-fold symmetric oscillation
is observed in the intensity variation, while the scattering
intensity remains constant. These features are accounted for in terms of the
peculiar ordering of the manganese 3d orbitals in BiMnO3. It is demonstrated
that the resonant peak persists up to 770 K with an anomaly around 440 K; these
high and low temperatures coincide with the structural transition temperatures,
seen in bulk, with and without a symmetry change, respectively. A possible
relationship of the orbital order with the ferroelectricity of the system is
discussed.Comment: 14 pages, 4 figure
Fano resonance in electron transport through parallel double quantum dots in the Kondo regime
Electron transport through parallel double quantum dot system with interdot
tunneling and strong on-site Coulomb interaction is studied in the Kondo regime
by using the finite- slave boson technique. For a system of quantum dots
with degenerate energy levels, the linear conductance reaches the unitary limit
() due to the Kondo effect at low temperature when the interdot
tunneling is absent. As the interdot tunneling amplitude increases, the
conductance decreases in the singly occupied regime and a conductance plateau
structure appears. In the crossover to the doubly occupied regime, the
conductance increases to reach the maximum value of . For parallel
double dots with different energy levels, we show that the interference effect
plays an important role in the electron transport. The linear conductance is
shown to have an asymmetric line shape of the Fano resonance as a function of
gate voltage.Comment: 15 pages, 5 figure
Detection Algorithms for Molecular MIMO
In this paper, we propose a novel design for molecular communication in which
both the transmitter and the receiver have, in a 3-dimensional environment,
multiple bulges (in RF communication this corresponds to antenna). The proposed
system consists of a fluid medium, information molecules, a transmitter, and a
receiver. We simulate the system with a one-shot signal to obtain the channel's
finite impulse response. We then incorporate this result within our
mathematical analysis to determine interference. Molecular communication has a
great need for low complexity, hence, the receiver may have incomplete
information regarding the system and the channel state. Thus, for the cases of
limited information set at the receiver, we propose three detection algorithms,
namely adaptive thresholding, practical zero forcing, and Genie-aided zero
forcing.Comment: 6 pages, 6 figures, 2015 IEEE ICC accepte
Quantitative study of molecular N_2 trapped in disordered GaN:O films
The structure of disordered GaN:O films grown by ion-assisted deposition is
investigated using x-ray absorption near-edge spectroscopy and Raman
spectroscopy. It is found that between 4 and 21 % of the nitrogen in the films
is in the form of molecular N_2 that interacts only weakly with the surrounding
matrix. The anion to cation ratio in the GaN:O host remains close to unity, and
there is a close correlation between the N_2 fraction, the level of oxygen
impurities, and the absence of short-range order in the GaN:O matrix.Comment: 5 pages, 3 figure
Optical Morphology Evolution of Infrared Luminous Galaxies in GOODS-N
We combine optical morphologies and photometry from HST, redshifts from Keck,
and mid-infrared luminosities from Spitzer for an optically selected sample
of~800 galaxies in GOODS-N to track morphology evolution of infrared luminous
galaxies (LIRGs) since redshift z=1. We find a 50% decline in the number of
LIRGs from z~1 to lower redshift, in agreement with previous studies. In
addition, there is evidence for a morphological evolution of the populations of
LIRGs. Above z=0.5, roughly half of all LIRGs are spiral, the
peculiar/irregular to spiral ratio is ~0.7, and both classes span a similar
range of L_{IR} and M_B. At low-z, spirals account for one-third of LIRGs, the
peculiar to spiral fraction rises to 1.3, and for a given M_B spirals tend to
have lower IR luminosity than peculiars. Only a few percent of LIRGs at any
redshift are red early-type galaxies. For blue galaxies (U-B < 0.2), M_B is
well correlated with log(L_{IR}) with an RMS scatter (about a bivariate linear
fit) of ~0.25 dex in IR luminosity. Among blue galaxies that are brighter than
M_B = -21, 75% are LIRGs, regardless of redshift. These results can be
explained by a scenario in which at high-z, most large spirals experience an
elevated star formation rate as LIRGs. Gas consumption results in a decline of
LIRGs, especially in spirals, to lower redshifts.Comment: 6 pages, 2 figures, accepted ApJ
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