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Journal of Applied Physics : Spatio-temporal Talbot phenomenon usi...

By: J. S. Gómez-Díaz, A. Alvarez-Melcon, S. Gupta, and C. Caloz

Description: A spatial-temporal Talbot phenomenon, based on metamaterial composite right/left-handed (CRLH) leaky-wave antennas (LWAs), is presented. This phenomenon, reported in the microwave domain, is based on the combination of the conventional spatial monochromatic Talbot effect and the transient (polychromatic) character of the pulse radiation phenomenon in the LWA structure. When the elements of a periodic CRLH LWA array are fed simultaneously by an input pulse, t...

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Journal of Applied Physics : Growth and characterization of Er-dop...

By: Andrea Arcangeli, Daniela Parisi, Alessandra Toncelli, Mauro Tonelli, Marco Bazzan et al

Description: Single crystal lithium niobate fibers with diameters ranging from 1 to 3 mm have successfully been grown by the micro-pulling-down technique. The fibers are doped with various Er doping levels from 0 to 0.7 mol % and appear to be transparent and crack-free. The study includes x-ray structural investigation and complete spectroscopic characterization. The analysis shows a good homogeneity of composition, and the comparison with bulk crystals demonstrates the ...

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Biblioteca Hispanica : Notions of Natural History, to Reach Children

By: Jose Maria Solano and Eulate
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Applied Physics Letters : Multilayered solid-state organic laser f...

By: K. Yamashita, A. Arimatsu, N. Takeuchi, M. Takayama, K. Oe et al

Description: This paper describes an organic dye-doped polymeric laser with a multilayered structure of active waveguides. Using the technique of photonanoimprint lithography, organic active-waveguide layers with distributed-feedback cavities and a polymeric intermediate cladding layer were stacked on a silica substrate. Under optical pumping, lasing oscillations at 427 and 636 nm, which correspond to the Bragg reflection wavelengths in the respective active waveguides, ...

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Review of Scientific Instruments : Correction of spherical aberrat...

By: Alexander Pikin and Ahovi Kponou

Description: Two methods to correct spherical aberration in electrostatic gridded lenses have been studied using ray-tracing simulations. Both methods are based on modifying the electrostatic field on the radial periphery of the lens. In the simplest case, the modification is done by extending the grid support axially. In the second method, the electric field on a radial periphery of the lens is modified by applying optimum voltage on an isolated correcting electrode. It...

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Applied Physics Letters : Multilevel sensitization of Er3+ in low-...

By: Oleksandr Savchyn, Ravi M. Todi, Kevin R. Coffey, and Pieter G. Kik

Description: The dynamics of Er3+ excitation in low-temperature-annealed Si-rich SiO2 are studied. It is demonstrated that Si-excess-related indirect excitation is fast (transfer time τtr<27 ns) and occurs into higher lying Er3+ levels as well as directly into the first excited state (4I13/2). By monitoring the time-dependent Er3+ emission at 1535 nm, the multilevel nature of the Er3+ sensitization is shown to result in two types of excitation of the 4I13/2 state: a fast...

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Applied Physics Letters : Organic heterostructure device with nonv...

By: Frank Lindner, Karsten Walzer, and Karl Leo

Description: Recently, several memory devices based on organic semiconductors were reported. In most cases, single organic layers were employed, and the switching mechanisms were not fully understood. Here, we report on a novel device structure based on electrically doped organic heterostructures showing highly stable memory behavior. The organic layers are embedded between a bottom indium tin oxide and a top metal contact and form a quantum well-like structure. The devi...

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Review of Scientific Instruments : A method for removing surfactan...

By: J. Kou and J. R. Saylor

Description: The study of heat, mass, and momentum transport across an air/water interface is an aspect of fluid mechanics where the presence of surfactant monolayers can play a significant role. Experimental studies of air/water transport typically require a method for cleaning the air/water interface so that it is free from any contaminating surfactant monolayer. This may be for the sake of running an experiment under clean surface conditions, or to clean the surface p...

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Journal of Applied Physics : An atomistic-based correction of the ...

By: S. Rodríguez-Bolívar, F. M. Gómez-Campos, and J. E. Carceller

Description: In this work, we propose a correction to the effective mass approach (EMA) to be used in Si quantum dot simulations. This correction tries to connect the different ways of modeling quantum dots within tight binding (considering the actual positions of the atoms and using additional atoms to passivate the surfaces) with those within the EMA, adapting the size of the simulated quantum dots to take the difference into account. With this aim, we implemented a 6×...

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Journal of Applied Physics : Comparison of sensitivities of carbon...

By: Masuhiro Abe, Katsuyuki Murata, Tatsuaki Ataka, and Kazuhiko Matsumoto

Description: The sensitivities of biosensors using top-gate-type carbon nanotube field-effect transistors (CNT-FETs) with and without a top metal gate were compared. The CNT-FET biosensor without the top metal gate (sensor I) showed about three times higher transconductance than the one with the top metal gate (sensor II) when they were modulated by a reference gate electrode placed in a solution. Further, the sensitivity of sensor I was three times higher than sensor II...

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Review of Scientific Instruments : Microbeam-integrated multiphoto...

By: Alan W. Bigelow, Charles R. Geard, Gerhard Randers-Pehrson, and David J. Brenner

Description: Multiphoton microscopy has been added to the array of imaging techniques at the endstation for the Microbeam II cell irradiator at Columbia University’s Radiological Research Accelerator Facility (RARAF). This three-dimensional (3D), laser-scanning microscope functions through multiphoton excitation, providing an enhanced imaging routine during radiation experiments with tissuelike samples, such as small living animals and organisms. Studies at RARAF focus o...

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Physics of Plasmas : Effect of a periodic electrostatic potential ...

By: C. A. Ordonez

Description: A classical trajectory Monte Carlo study is reported regarding the motion of a charged particle that is caused to drift across a magnetic field toward an artificially structured boundary, which produces a spatially periodic electrostatic potential. It is found that, for the system studied, the drift toward the boundary is inhibited if the particle’s speed associated with motion parallel to the magnetic field is much larger than the particle’s speed associate...

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The Journal of Chemical Physics : Kinetic and theoretical study of...

By: Andrés Garzón, José Albaladejo, Alberto Notario, Tomás Peña-Ruiz, and Manuel Fernández-Gómez

Description: The reactions of Cl with a series of linear thiols: 1-propanethiol (k1), 1-butanethiol (k2), and 1-pentanethiol (k3) were investigated as a function of temperature (in the range of 268–379 K) and pressure (in the range of 50–200 Torr) by laser photolysis-resonance fluorescence. Only 1-propanethiol has previously been studied, but at 1 Torr of total pressure. The derived Arrhenius expressions obtained using our kinetic data were as follows: k1 = (3.97±0.44)×1...

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Chaos : Cryptanalysis of a chaotic communication scheme using adap...

By: Ying Liu and Wallace K. S. Tang

Description: This paper addresses the cryptanalysis of a secure communication scheme recently proposed by Wu [Chaos 16, 043118 (2006) ], where the information signal is modulated into a system parameter of a unified chaotic system. With the Kerckhoff principle, assuming that the structure of the cryptosystem is known, an adaptive observer can be designed to synchronize the targeted system, so that the transmitted information and the user-specific parameters are obtained....

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Journal of Applied Physics : Microwave dielectric and Raman scatte...

By: K. Sudheendran, K. C. James Raju, Manoj K. Singh, and Ram S. Katiyar

Description: Bismuth zinc niobate (Bi1.5Zn1.0Nb1.5O7) thin films were deposited on fused silica substrates by pulsed laser deposition. Its phase composition and microstructure were characterized by x-ray diffraction and atomic force microscopy. The as deposited films were amorphous and all of them were crystallized after a postdeposition annealing at 600 °C for 30 min in air. The crystallite size of the films was found to be varying between 31 and 60 nm with respect to t...

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Journal of Applied Physics : Relaxations in Ba2BiSbO6 double compl...

By: Manoel Carvalho Castro, Carlos William de Araujo Paschoal, Frank C. Snyder, and Michael W. Lufaso

Description: The electric properties of the complex double perovskite Ba2BiSbO6 have been investigated using impedance spectroscopy in the frequency range from 1 Hz up to 1 MHz and in the temperature range from room temperature up to 560 K. There are two contributions to the electrical properties due to the grain and grain boundary. The oxygen vacancies play an important role in the conductivity and strongly increase the dielectric constant at high temperatures. The anal...

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Applied Physics Letters : Enhanced field emission from ZnO nanotet...

By: Chi Li, Kai Hou, Xiaxi Yang, Ke Qu, Wei Lei et al

Description: Field emission properties of screen-printed ZnO nanotetrapods on a carbon nanofiber buffered Ag electrode were studied. The turn-on electric field (at a current of 0.1 μA/cm2) and maximum emission current are 0.6 V/μm and 2.8 mA/cm2 (at a field of 2.2 V/μm), which were significantly improved compared to the control device made of ZnO nanotetrapods on Ag directly without a carbon nanofiber buffer. The improved field emission is due to the better contact (both...

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Applied Physics Letters : Spin precession induced by an effective ...

By: Genhua Liu, Yonghai Chen, Caihong Jia, and Zhanguo Wang

Description: We theoretically study the spatial behaviors of the spin precession in a two-dimensional electron system with spin-orbit interaction. Through analysis of interaction between the spin and the effective magnetic field in the system, we obtain the general conditions to generate a persistent spin helix and predict a persistent spin helix pattern in [001] -grown quantum wells. Particularly, we demonstrate that the phase of spin can be locked to propagate in a qu...

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Applied Physics Letters : Crystalline silicon carbide nanocones an...

By: Zhenyu Liu, Lijie Ci, V. Srot, N. Y. Jin-Phillipp, Peter A. van Aken et al

Description: We present the formations of crystalline silicon carbide (SiC) nanocones and heterostructures catalyzed by iron nanoparticles, originally encapsulated in graphite-like carbon shells, via the vapor-liquid-solid process. We propose that the nanocone shape is due to the release of iron nanoparticles from their carbon shells followed by agglomeration, where the increasing size of the iron nanoparticle during SiC growth creates the nanocone shape. The release and...

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Biblioteca Hispanica : Testing an Introduction to the Study of Nat...

By: Augusto G. Linares
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