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Applied Physics Letters : Restoration of high spatial frequency at...

By: Du Hyun Beak, Jin Woo Yoon, Jae Sung Shin, and Hong Jin Kong

Description: We have found experimentally that it is possible to restore the high spatial frequency of optical images by using stimulated Brillouin scattering (SBS) with a prepulse. The Stokes wave usually has to lose the high spatial frequency because of the necessary energy to generate the acoustic grating. However, this problem has been resolved by using a prepulse method. We have achieved an amplitude increase of ~41% compared to the normal SBS scheme at a spatial ...

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Biblioteca Hispanica : Elementary Notions of Natural History

By: Alejandro Jose Martinez De La Raga
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Journal of Mathematical Physics : Analytic integrability of a Chua...

By: Jaume Llibre and Clàudia Valls

Description: We consider the system = a(z−a1x3−a2x2−bx), = −z, = −b1x+y+b2z, where a and b are parameters and b1 = 7/10, b2 = 6/25, a1 = 44/3, and a2 = 41/2. We analyze the existence of local and global analytic first integrals.

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Physics of Plasmas : Ion-acoustic solitary waves and their interac...

By: Jiu-ning Han, Sheng-lin Du, and Wen-shan Duan

Description: This paper discusses the existence of ion-acoustic solitary waves and their interaction in a weakly relativistic two-dimensional thermal plasma. Two Korteweg–de Vries equations for small but finite amplitude solitary waves in both ξ and η directions are derived. The phase shifts and trajectories of two solitary waves after the collision with an arbitrary angle α are also obtained. The effects of parameters of the normalized ion temperature σ, the ratio of he...

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The Journal of Chemical Physics : Optimized effective potentials f...

By: Tim Heaton-Burgess and Weitao Yang

Description: We investigate the use of a regularized optimized effective potential (OEP) energy functional and L-curve procedure [ T. Heaton-Burgess, F. A. Bulat, and W. Yang, Phys. Rev. Lett. 98, 256401 (2007) ] for determining physically meaningful OEPs from arbitrary combinations of finite orbital and potential basis sets. The important issue of the manner in which the optimal regularization parameter is determined from the L-curve perspective is reconsidered with the...

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Journal of Applied Physics : Optical properties of Yb3+ doped Lu3A...

By: Alessandra Toncelli, Mohamed Alshourbagy, and Mauro Tonelli

Description: Yb doped Lu3Al5O12 single crystal fibers has been grown with various Yb3+ ion concentrations: 2%, 5%, 10%, 15%, and 50% Yb doping levels. The diameter of the fibers is around 3 mm and their length is up to 110 mm. The fibers have been annealed in air at 1400 °C for 24 h to remove Yb2+ produced during the growth in the fibers. Structural characterization by x-ray diffraction method has been performed to confirm the monocrystalline phase and the orientation of...

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Biblioteca Hispanica : Compendium Natural History Applied to Veter...

By: Santos Rock and Neighbor
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Physics of Fluids : Evolution of neutral and charged droplets in a...

By: M. A. Fontelos, U. Kindelán, and O. Vantzos

Description: We study the evolution of drops of a very viscous and conducting fluid under the influence of an external electric field. The drops may be neutral or may be charged with some amount of electric charge. If both the external electric field and total drop charge are sufficiently small, then prolate spherical shapes develop according to Taylor’s observations. For sufficiently large charge and/or external field a self-similar conelike singularity develops in a me...

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Review of Scientific Instruments : Radio-frequency reflectometry o...

By: L. J. Taskinen, R. P. Starrett, T. P. Martin, A. P. Micolich, A. R. Hamilton et al

Description: We have embedded an AlGaAs/GaAs based, gated two-dimensional (2D) hole system (2DHS) into an impedance transformer LC circuit and show that by using radio-frequency reflectometry it is possible to perform sensitive, large bandwidth, electrical resistance measurements of 2D systems at millikelvin temperatures. We construct a simple lumped element model where the gated 2DHS is described as a resistive transmission line. The model gives a qualitative understand...

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Journal of Applied Physics : Influence of annealing on the Er lumi...

By: A. Kanjilal, L. Rebohle, M. Voelskow, W. Skorupa, and M. Helm

Description: The impact of rapid thermal annealing (RTA) in producing samples by sequential implantation of Si and Er ions into a 200 nm SiO2 layer combined with different annealing cycles as well as the corresponding room-temperature visible and infrared photoluminescence (PL) have been studied. The Er-related PL intensity at 1533 nm for the samples prepared by implanting Si with subsequent annealing, followed by Er implantation, and final annealing (type I) was found t...

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Chaos : Dynamical parameter identification from a scalar time series

By: Dongchuan Yu and Fang Liu

Description: If a drive system with unknown parameters represents “reality” and the response system a “computational model,” the unidirectional coupling can be used to change model parameters, as well as the model state, such that both systems synchronize with each other and model parameters coincide with their true values of “reality.” Such a parameter identification method is called adaptive synchronization (also autosynchronization) method and is widely used in the li...

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Applied Physics Letters : Bandgap engineering by tuning particle s...

By: M. B. Sahana, C. Sudakar, G. Setzler, A. Dixit, J. S. Thakur et al

Description: We report the structural and optical properties of xSnO2–yFe2O3 nanocrystalline composite thin films. SnO2 and Fe2O3 exhibit strong phase separation instability and their particle size and crystallinity are tunable by changing their composition and annealing temperature. The bandgap for these composites continuously increases from 2.3 to 3.89 eV. We discuss the increasing bandgap values in terms of the quantum confinement effect manifested by the decreasing ...

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Journal of Applied Physics : Study of laser excited vibration of s...

By: Yaqin Song, Bernard Cretin, D. M. Todorovic, and Pascal Vairac

Description: In this paper an interferometric setup called “thermoelastic microscopy” has been used to measure the vibration response of the semiconductor cantilevers under modulated laser thermal source. The small vibration amplitude has been detected well below 10 pm magnitude in accurate adjustment conditions. The results showed that experimental responses have a good agreement with the theoretical ones. Also from the analysis we could conclude that the signal amplitu...

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Review of Scientific Instruments : Low-frequency mechanical spectr...

By: Xuebang Wu, Qiaoling Xu, Jiapeng Shui, and Zhengang Zhu

Description: A low-frequency mechanical spectroscopy approach for liquids was proposed for studying conformational transition of polymer chains in concentrated solutions. The technique is applied to aqueous solutions of a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer in order to determine if chain conformation is altered in response to temperature. Two transitions are revealed by mechanical spectra and verified by differ...

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Physics of Plasmas : The structure of the electron outflow jet in ...

By: Michael Hesse, Seiji Zenitani, and Alex Klimas

Description: Particle-in-cell simulations and analytic theory are applied to the study of the electron outflow jet in collisionless magnetic reconnection. In these jets, which have also been identified in spacecraft observations, electron flow speeds in thin layers exceed the E×B drift, suggesting that electrons are unmagnetized. In this study, we find the surprising result that the electron flow jets can be explained by a combination of E×B drifts and of diamagnetic eff...

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Journal of Applied Physics : Equivalent magnetic charge in helicoi...

By: Roberto Muscia

Description: In this paper we show that magnetostatic models of permanent magnets, based on distributions of magnetic charge and shaped by a helicoidal geometry of cylindrical type, have the volume charge density ρM equal to zero. This result is valid when (i) the modulus of the vector physical magnetization density M has a constant value in all the points of the helicoidal magnet and (ii) M has the same direction of an oriented straight line having a constant angle with...

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Biblioteca Hispanica : Inaugural Prayer Read at the University of ...

By: Antonio Casares and Rodrigo
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Physics of Fluids : A better nondimensionalization scheme for slen...

By: M. M. Weislogel, Y. Chen, and D. Bolleddula

Description: A scaling of the two-dimensional Laplacian operator is demonstrated for certain solutions (at least) to Poisson’s equation. It succeeds by treating the operator as a single geometric scale entity. The belated and rather subtle method provides an efficient assessment of the geometrical dependence of the problem and is preferred when practicable to the hydraulic diameter or term-by-term scaling for slender fully developed laminar flows. The improved accuracy f...

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Journal of Applied Physics : Green light emission from InGaN multi...

By: W. Feng, V. V. Kuryatkov, A. Chandolu, D. Y. Song, M. Pandikunta et al

Description: Selective area epitaxy has been used to grow pyramidal GaN stripes, followed by InGaN multiple quantum well (MQW) structures, in order to produce long-wavelength green light emission. Stripes oriented along 〈110〉 produce smooth {101} sidewall facets. The room-temperature optical properties are investigated by cathodoluminescence spectroscopy using a scanning electron microscope. MQWs grown in unmasked reference regions exhibit emission at 450 nm. The stripe ...

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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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