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Nanoimaging of Organic Charge Retention Effects: Implications for Nonvolatile Memory, Neuromorphic Computing, and High Dielectric Breakdown Devices
While a large variety of organic and molecular materials have been found to exhibit charge memory effects, the underlying mechanism is not well-understood, which hinders rational device design. Here, we study the charge retention mechanism of a nanoscale memory system, an organic monolayer on a silicon substrate, with Au nanoparticles on top serving as the electrical contact. Combining scanning probe imaging/manipulation and density functional simulations, we observe stable charge retention effects in the system and attributed it to polaron effects at the amine functional groups. Our findings can pave the way for applications in nonvolatile memory, neuromorphic computing, and high dielectric breakdown devices
A Dynamic Programming Solution to Bounded Dejittering Problems
We propose a dynamic programming solution to image dejittering problems with
bounded displacements and obtain efficient algorithms for the removal of line
jitter, line pixel jitter, and pixel jitter.Comment: The final publication is available at link.springer.co
Properties of Central Caustics in Planetary Microlensing
To maximize the number of planet detections, current microlensing follow-up
observations are focusing on high-magnification events which have a higher
chance of being perturbed by central caustics. In this paper, we investigate
the properties of central caustics and the perturbations induced by them. We
derive analytic expressions of the location, size, and shape of the central
caustic as a function of the star-planet separation, , and the planet/star
mass ratio, , under the planetary perturbative approximation and compare the
results with those based on numerical computations. While it has been known
that the size of the planetary caustic is \propto \sqrt{q}, we find from this
work that the dependence of the size of the central caustic on is linear,
i.e., \propto q, implying that the central caustic shrinks much more rapidly
with the decrease of compared to the planetary caustic. The central-caustic
size depends also on the star-planet separation. If the size of the caustic is
defined as the separation between the two cusps on the star-planet axis
(horizontal width), we find that the dependence of the central-caustic size on
the separation is \propto (s+1/s). While the size of the central caustic
depends both on and q, its shape defined as the vertical/horizontal width
ratio, R_c, is solely dependent on the planetary separation and we derive an
analytic relation between R_c and s. Due to the smaller size of the central
caustic combined with much more rapid decrease of its size with the decrease of
q, the effect of finite source size on the perturbation induced by the central
caustic is much more severe than the effect on the perturbation induced by the
planetary caustic. Abridged.Comment: 5 pages, 4 figures, ApJ accepte
Mixing of Ground States in Vertex Models
We consider the analogue of the 6-vertex model constructed from alternating
spin n/2 and spin m/2 lines, where . We identify the transfer matrix
and the space on which it acts in terms of the representation theory of
. We diagonalise the transfer matrix and compute the S-matrix. We
give a trace formula for local correlation functions. When n=1, the 1-point
function of a spin m/2 local variable for the alternating lattice with a
particular ground state is given as a linear combination of the 1-point
functions of the pure spin m/2 model with different ground states. The mixing
ratios are calculated exactly and are expressed in terms of irreducible
characters of and the deformed Virasoro algebra.Comment: 12 pages, LaTeX, typos correcte
Imaging features of rare mesenychmal liver tumours: beyond haemangiomas.
Tumours arising from mesenchymal tissue components such as vascular, fibrous and adipose tissue can manifest in the liver. Although histopathology is often necessary for definitive diagnosis, many of these lesions exhibit characteristic imaging features. The radiologist plays an important role in suggesting the diagnosis, which can direct appropriate immunohistochemical staining at histology. The aim of this review is to present clinical and imaging findings of a spectrum of mesenchymal liver tumours such as haemangioma, epithelioid haemangioendothelioma, lipoma, PEComa, angiosarcoma, inflammatory myofibroblastic tumour, solitary fibrous tumour, leiomyoma, leiomyosarcoma, Kaposi sarcoma, mesenchymal hamartoma, undifferentiated embryonal sarcoma, rhabdomyosarcoma and hepatic metastases. Knowledge of the characteristic features of these tumours will aid in guiding the radiologic diagnosis and appropriate patient management
Density functional theory of the phase diagram of maximum density droplets in two-dimensional quantum dots in a magnetic field
We present a density-functional theory (DFT) approach to the study of the
phase diagram of the maximum density droplet (MDD) in two-dimensional quantum
dots in a magnetic field. Within the lowest Landau level (LLL) approximation,
analytical expressions are derived for the values of the parameters (number
of electrons) and (magnetic field) at which the transition from the MDD to
a ``reconstructed'' phase takes place. The results are then compared with those
of full Kohn-Sham calculations, giving thus information about both correlation
and Landau level mixing effects. Our results are also contrasted with those of
Hartree-Fock (HF) calculations, showing that DFT predicts a more compact
reconstructed edge, which is closer to the result of exact diagonalizations in
the LLL.Comment: ReVTeX 3.
Fusion of the -Vertex Operators and its Application to Solvable Vertex Models
We diagonalize the transfer matrix of the inhomogeneous vertex models of the
6-vertex type in the anti-ferroelectric regime intoducing new types of q-vertex
operators. The special cases of those models were used to diagonalize the s-d
exchange model\cite{W,A,FW1}. New vertex operators are constructed from the
level one vertex operators by the fusion procedure and have the description by
bosons. In order to clarify the particle structure we estabish new isomorphisms
of crystals. The results are very simple and figure out representation
theoretically the ground state degenerations.Comment: 35 page
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