965 research outputs found
K Means Segmentation of Alzheimers Disease in PET scan datasets: An implementation
The Positron Emission Tomography (PET) scan image requires expertise in the
segmentation where clustering algorithm plays an important role in the
automation process. The algorithm optimization is concluded based on the
performance, quality and number of clusters extracted. This paper is proposed
to study the commonly used K Means clustering algorithm and to discuss a brief
list of toolboxes for reproducing and extending works presented in medical
image analysis. This work is compiled using AForge .NET framework in windows
environment and MATrix LABoratory (MATLAB 7.0.1)Comment: International Joint Conference on Advances in Signal Processing and
Information Technology, SPIT201
Observations of temporal group delays in slow-light multiple coupled photonic crystal cavities
We demonstrate temporal group delays in coherently-coupled high-Q multi-cavity photonic crystals, in an all-optical analogue to electromagnetically induced transparency. We report deterministic control of the group delay up to 4× the single cavity lifetime in our CMOS-fabricated room-temperature chip. Supported by three-dimensional numerical simulations and theoretical analyses, our multi-pump beam approach enables control of the multi-cavity resonances and inter-cavity phase, in both single and double transparency peaks. The standing-wave wavelength-scale photon localization allows direct scalability for chip-scale optical pulse trapping and coupled-cavity QED
Efficient Red Organic Light Emitting Diodes of Nona Coordinate Europium Tris(β-diketonato) Complexes Bearing 4'-Phenyl-2,2':6',2''- terpyridine
Two novel nona-coordinated Eu(III) complexes [Eu(btfa) 3(Ph-TerPyr)] (Eu-1) and [Eu(NTA) 3(Ph-TerPyr)] (Eu-2) have been synthesized and characterized. The structure of the complexes was elucidated by density functional theory (DFT) methods. The experimental photophysical properties of the complexes were investigated and complemented with theoretical calculations. Effective energy transfer (ET) pathways for the sensitized red luminescence is discussed. The complexes were tested as emitting layers (EML) in organic light emitting diodes (OLEDs). At the optimum doping concentration of 4 wt.%, the double-EML OLEDs of Eu-1 exhibited red electroluminescence (EL) with an EQE of 4.0 % and maximum brightness (B)=1179 cd/m 2, maximum current efficiency (η c)=5.64 cd/A, and maximum power efficiency (η p)=4.78 lm/W at the current density (J) of 10 mA/cm 2. Interestingly, the double-EML OLEDs of Eu-2 at the optimum concentration of 3 wt.%, displayed an outstanding EL performance with EQE of 7.32 % and B=838 cd/m 2, η c=10.19 cd/A and η p=10.33 lm/W at J=10 mA/cm 2. The EL performance of this device is among the best reported for devices incorporating a europium complex as a red emitter.</p
Efficient Red Organic Light Emitting Diodes of Nona Coordinate Europium Tris(β-diketonato) Complexes Bearing 4'-Phenyl-2,2':6',2''- terpyridine
Two novel nona-coordinated Eu(III) complexes [Eu(btfa) 3(Ph-TerPyr)] (Eu-1) and [Eu(NTA) 3(Ph-TerPyr)] (Eu-2) have been synthesized and characterized. The structure of the complexes was elucidated by density functional theory (DFT) methods. The experimental photophysical properties of the complexes were investigated and complemented with theoretical calculations. Effective energy transfer (ET) pathways for the sensitized red luminescence is discussed. The complexes were tested as emitting layers (EML) in organic light emitting diodes (OLEDs). At the optimum doping concentration of 4 wt.%, the double-EML OLEDs of Eu-1 exhibited red electroluminescence (EL) with an EQE of 4.0 % and maximum brightness (B)=1179 cd/m 2, maximum current efficiency (η c)=5.64 cd/A, and maximum power efficiency (η p)=4.78 lm/W at the current density (J) of 10 mA/cm 2. Interestingly, the double-EML OLEDs of Eu-2 at the optimum concentration of 3 wt.%, displayed an outstanding EL performance with EQE of 7.32 % and B=838 cd/m 2, η c=10.19 cd/A and η p=10.33 lm/W at J=10 mA/cm 2. The EL performance of this device is among the best reported for devices incorporating a europium complex as a red emitter.</p
A Tris β-Diketonate Europium(III) Complex Based OLED Fabricated by Thermal Evaporation Method Displaying Efficient Bright Red Emission
202209 bcwwNot applicableRGCOthersHis Majesty’s Trust Fund for Strategic Research; Brazilian funding agencies: CAPES, CNPq,FACEPE and FAPITEC/SE; Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials; Hong Kong Polytechnic University; Endowed Professorship in Energy from Ms Clarea Au; NSFC; outh Innovation Promotion Association of Chinese Academy of Sciences; Engineering and Physical Sciences Research Council (EPSRC)Published24 month
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Strongly coupled slow-light polaritons in one-dimensional disordered localized states
Cavity quantum electrodynamics advances the coherent control of a single quantum emitter with a quantized radiation field mode, typically piecewise engineered for the highest finesse and confinement in the cavity field. This enables the possibility of strong coupling for chip-scale quantum processing, but till now is limited to few research groups that can achieve the precision and deterministic requirements for these polariton states. Here we observe for the first time coherent polariton states of strong coupled single quantum dot excitons in inherently disordered one-dimensional localized modes in slow-light photonic crystals. Large vacuum Rabi splittings up to 311.μeV are observed, one of the largest avoided crossings in the solid-state. Our tight-binding models with quantum impurities detail these strong localized polaritons, spanning different disorder strengths, complementary to model-extracted pure dephasing and incoherent pumping rates. Such disorder-induced slow-light polaritons provide a platform towards coherent control, collective interactions, and quantum information processing
The Muonium Atom as a Probe of Physics beyond the Standard Model
The observed interactions between particles are not fully explained in the
successful theoretical description of the standard model to date. Due to the
close confinement of the bound state muonium () can be used as
an ideal probe of quantum electrodynamics and weak interaction and also for a
search for additional interactions between leptons. Of special interest is the
lepton number violating process of sponteanous conversion of muonium to
antimuonium.Comment: 15 pages,6 figure
Synthesis and Photophysical Properties of Ternary β-Diketonate Europium(III) Complexes Incorporating Bipyridine and its Derivatives
Two new octa-coordinated ternary europium(III) complexes of the type [Eu(btfa)3(Br2-bpy)] (Eu-1) and [Eu(btfa)3(PhE2-bpy)] (Eu-2) (where btfa = 4,4,4-trifluoro-1-phenyl-1,3-butanedione, Br2-bpy = 5,5'-dibromo-2,2'-bipyridine, PhE2-bpy 5,5'-bis(phenylethynyl)-2,2'-bipyridine) together with a previously reported complex [Eu(btfa)3(bpy)] (Eu-3) have been synthesized. The complexes have been characterized by analytical and spectroscopic methods. The photophysical properties of the complexes have also been analyzed both experimentally and theoretically. The contribution of each ligand to the sensitized Eu(III) photoluminescence (PL) has been analyzed and is discussed. An energy transfer (ET) mechanism is proposed and discussed for the sensitized Eu(III) emission using experimental and theoretical data. The Eu(III) complex incorporating the parent bpy showed impressive performance as a double-emitting layer (EML) red organic light emitting diodes (R-OLEDs)
Entanglement, Mixedness, and Spin-Flip Symmetry in Multiple-Qubit Systems
A relationship between a recently introduced multipartite entanglement
measure, state mixedness, and spin-flip symmetry is established for any finite
number of qubits. It is also shown that, within those classes of states
invariant under the spin-flip transformation, there is a complementarity
relation between multipartite entanglement and mixedness. A number of example
classes of multiple-qubit systems are studied in light of this relationship.Comment: To appear in Physical Review A; submitted 14 May 200
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