169 research outputs found
A modeling approach to understanding OLED performance improvements arising from spatial variations in guest:host blend ratio
Phosphorescent organic light emitting diodes (OLEDs) suffer from efficiency roll off, where device efficiency rapidly decays at higher luminance. One strategy to minimize this loss of efficiency at higher luminance is the use of non-uniform or graded guest:host blend ratios within the emissive layer. This work applies a multi-scale modeling framework to elucidate the mechanisms by which a non-uniform blend ratio can change the performance of an OLED. Mobility and exciton data are extracted from a kinetic Monte–Carlo model, which is then coupled to a drift diffusion model for fast sampling of the parameter space. The model is applied to OLEDs with uniform, linear, and stepwise graduations in the blend ratio in the emissive layer. The distribution of the guests in the film was found to affect the mobility of the charge carriers, and it was determined that having a graduated guest profile broadened the recombination zone, leading to a reduction in second order annihilation rates. That is, there was a reduction in triplet–triplet and triplet-polaron annihilation. Reducing triplet–triplet and triplet-polaron annihilation would lead to an improvement in device efficiency
Synchronization and Coarsening (without SOC) in a Forest-Fire Model
We study the long-time dynamics of a forest-fire model with deterministic
tree growth and instantaneous burning of entire forests by stochastic lightning
strikes. Asymptotically the system organizes into a coarsening self-similar
mosaic of synchronized patches within which trees regrow and burn
simultaneously. We show that the average patch length grows linearly with
time as t-->oo. The number density of patches of length L, N(L,t), scales as
^{-2}M(L/), and within a mean-field rate equation description we find
that this scaling function decays as e^{-1/x} for x-->0, and as e^{-x} for
x-->oo. In one dimension, we develop an event-driven cluster algorithm to study
the asymptotic behavior of large systems. Our numerical results are consistent
with mean-field predictions for patch coarsening.Comment: 5 pages, 4 figures, 2-column revtex format. To be submitted to PR
Generalized Relativistic Meson Wave Function
We study the most general, relativistic, constituent meson
wave function within a new covariant framework. We find that by including a
tensor wave function component, a pure valence quark model is now capable of
reproducing not only all static pion data (, )
but also the distribution amplitude, form factor , and structure
functions. Further, our generalized spin wave function provides a much better
detailed description of meson properties than models using a simple
relativistic extension of the nonrelativistic wave function.Comment: 17 pages, REXTeX 3.0 file, (uuencoded postscript files of 8 figures
appended
Abel's Functional Equation and Eigenvalues of Composition Operators on Spaces of Real Analytic Functions
We obtain full description of eigenvalues and eigenvectors
of composition operators Cϕ : A (R) → A (R) for a real analytic self
map ϕ : R → R as well as an isomorphic description of corresponding
eigenspaces. We completely characterize those ϕ for which Abel’s equation
f â—¦ Ï• = f + 1 has a real analytic solution on the real line. We find
cases when the operator CÏ• has roots using a constructed embedding of
Ï• into the so-called real analytic iteration semigroups.(1) The research of the authors was partially supported by MEC and FEDER Project MTM2010-15200 and MTM2013-43540-P and the work of Bonet also by GV Project Prometeo II/2013/013. The research of Domanski was supported by National Center of Science, Poland, Grant No. NN201 605340. (2) The authors are very indebted to K. Pawalowski (Poznan) for providing us with references [26,27,47] and also explaining some topological arguments of [10]. The authors are also thankful to M. Langenbruch (Oldenburg) for providing a copy of [29].Bonet Solves, JA.; Domanski, P. (2015). Abel's Functional Equation and Eigenvalues of Composition Operators on Spaces of Real Analytic Functions. Integral Equations and Operator Theory. 81(4):455-482. https://doi.org/10.1007/s00020-014-2175-4S455482814Abel, N.H.: Determination d’une function au moyen d’une equation qui ne contient qu’une seule variable. In: Oeuvres Complètes, vol. II, pp. 246-248. 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Boron neutron capture therapy of ocular melanoma and intracranial glioma using p-boronophenylalanine
During conventional radiotherapy, the dose that can be delivered to the tumor is limited by the tolerance of the surrounding normal tissue within the treatment volume. Boron Neutron Capture Therapy (BNCT) represents a promising modality for selective tumor irradiation. The key to effective BNCT is selective localization of {sup 10}B in the tumor. We have shown that the synthetic amino acid p-boronophenylalanine (BPA) will selectively deliver boron to melanomas and other tumors such as gliosarcomas and mammary carcinomas. Systemically delivered BPA may have general utility as a boron delivery agent for BNCT. In this paper, BNCT with BPA is used in treatment of experimentally induced gliosarcoma in rats and nonpigmented melanoma in rabbits. The tissue distribution of boron is described, as is response to the BNCT. 6 refs., 4 figs., 1 tab
Proposed diagnostic criteria for classical CMML, CMML variants and pre-CMML conditions
Chronic myelomonocytic leukemia (CMML) is a myeloid neoplasm characterized by dysplasia, abnormal production and accumulation of monocytic cells and an elevated risk to transform into acute leukemia. Over the past two decades, our knowledge about the pathogenesis and molecular mechanisms in CMML has increased substantially. In parallel, better diagnostic criteria and therapeutic strategies have been developed. However, many questions remain regarding prognostication and optimal therapy. In addition, there is a need to define potential pre-phases of CMML and special CMML variants, and to separate these entities from each other and from conditions mimicking CMML. To address these unmet needs, an international consensus group met in a Working Conference in August 2018 and discussed open questions and issues around CMML, its variants, and pre-CMML conditions. The outcomes of this meeting are summarized herein and include diagnostic criteria and a proposed classification of pre-CMML conditions as well as refined minimal diagnostic criteria for classical CMML and special CMML variants, including oligomonocytic CMML and CMML associated with systemic mastocytosis. Moreover, we propose diagnostic standards and tools to delineate between normal, pre-CMML and CMML entities. These criteria and standards should facilitate diagnostic and prognostic evaluations in daily practice and clinical studies in applied hematology
the WAF method for non-homogeneous SWE with pollutant
This paper deals with the extension of the WAF method to discretize Shallow Water Equations with pollutants. We consider two different versions of the WAF method, by approximating the intermediate waves using the flux of HLL or the direct approach of HLLC solver. It is seen that both versions can be written under the same form with different definitions for the approximation of the velocity waves. We also propose an extension of the method to non-homogeneous systems. In the case of homogeneous systems it is seen that we can rewrite the third component of the numerical flux in terms of an intermediate wave speed approximation. We conclude that – in order to have the same relation for non-homogeneous systems – the approximation of the intermediate wave speed must be modified. The proposed extension of the WAF method preserves all stationary solutions, up to second order accuracy, and water at rest in an exact way, even with arbitrary pollutant concentration. Finally, we perform several numerical tests, by comparing it with HLLC solver, reference solutions and analytical solutions
Prox2 and Runx3 vagal sensory neurons regulate esophageal motility
Vagal sensory neurons monitor mechanical and chemical stimuli in the gastrointestinal tract. Major efforts are underway to assign physiological functions to the many distinct subtypes of vagal sensory neurons. Here, we use genetically guided anatomical tracing, optogenetics, and electrophysiology to identify and characterize vagal sensory neuron subtypes expressing Prox2 and Runx3 in mice. We show that three of these neuronal subtypes innervate the esophagus and stomach in regionalized patterns, where they form intraganglionic laminar endings. Electrophysiological analysis revealed that they are low-threshold mechanoreceptors but possess different adaptation properties. Lastly, genetic ablation of Prox2 and Runx3 neurons demonstrated their essential roles for esophageal peristalsis in freely behaving mice. Our work defines the identity and function of the vagal neurons that provide mechanosensory feedback from the esophagus to the brain and could lead to better understanding and treatment of esophageal motility disorders
Gendering the careers of young professionals: some early findings from a longitudinal study. in Organizing/theorizing: developments in organization theory and practice
Wonders whether companies actually have employees best interests at heart across physical, mental and spiritual spheres. Posits that most organizations ignore their workforce – not even, in many cases, describing workers as assets! Describes many studies to back up this claim in theis work based on the 2002 Employment Research Unit Annual Conference, in Cardiff, Wales
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