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Applied Physics Letters : Composition dependence of magnetocaloric...

By: A. Rebello and R. Mahendiran

Description: We investigated magnetic and magnetocaloric properties in Sm1−xSrxMnO3(x = 0.3–0.5). We report a magnetic field-driven first-order metamagnetic transition in the paramagnetic state in x = 0.4 and 0.5 and a second-order transition in x = 0.3. The highest magnetic entropy (−ΔSm = 1.41 J/mol K for ΔH = 5 T at T = 125 K) that occurs in x = 0.4 is associated with the metamagnetic transition resulting from the field-induced growth and coalescence of ferromagnetic ...

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Physics of Fluids : History force on an asymmetrically rotating bo...

By: Sukalyan Bhattacharya

Description: Experimental evidence shows that suspended particles preferentially migrate away from confining boundaries due to the effect of a shear flow. In this paper, we consider an asymmetric particle in Poiseuille flow and determine an inertial lift force which can contribute to the particle migration. Under the influence of Poiseuille flow in a slit pore, an arbitrary particle undergoes periodic rotation which is described by Jeffery’s orbit [ G. Jeffery, Proc. R. ...

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Journal of Mathematical Physics : On the divine clockwork: The spe...

By: Richard Durran, Andrew Neate, Aubrey Truman, and Feng-Yu Wang

Description: The correspondence limit of the atomic elliptic state in three dimensions is discussed in terms of Nelson’s stochastic mechanics. In previous work we have shown that this approach leads to a limiting Nelson diffusion, and here we discuss in detail the invariant measure for this process and show that it is concentrated on the Kepler ellipse in the plane z = 0. We then show that the limiting Nelson diffusion generator has a spectral gap; thereby proving that i...

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Journal of Applied Physics : Photobleaching-free infrared near-fie...

By: J. Generosi, G. Margaritondo, M. Kropf, H. Hirling, S. Catsicas et al

Description: High-resolution detection of specific molecules in cells is a major challenge in biology. We show that infrared scanning near-field microscopy can detect the spatial distribution of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid–type glutamate receptor clusters on hippocampal neurons. The GluR2 subunits were labeled with the die Alexa 488 and high-resolution infrared micrographs were taken at 6.25 μm. The absence of photobleaching makes this approach ...

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Physics of Fluids : Coherent flow states in a square duct

By: Håkan Wedin, Damien Biau, Alessandro Bottaro, and Masato Nagata

Description: The flow in a square duct is considered. Finite amplitude approximate traveling wave solutions, obtained using the self-sustaining-process approach introduced by Waleffe [Phys. Fluids 9, 883 (1997) ], are obtained at low to moderate Reynolds numbers and used as initial conditions in direct numerical simulations. The ensuing dynamics is analyzed in a suitably defined phase space. Only one among the traveling wave solutions found is capable of surviving for a ...

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Physics of Plasmas : On the nature of transport in near-critical d...

By: J. A. Mier, R. Sánchez, L. García, D. E. Newman, and B. A. Carreras

Description: The change in nature of radial transport in numerical simulations of near-critical dissipative-trapped-electron-mode turbulence is characterized as the relative strength of an additional diffusive transport channel (subdominant to turbulence) is increased from zero. In its absence, radial transport exhibits the lack of spatial and temporal scales characteristic of self-organized-critical systems. This dynamical regime survives up to diffusivity values which,...

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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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The Journal of Chemical Physics : Monte Carlo simulations of amphi...

By: Jonathan R. Davis and Athanassios Z. Panagiotopoulos

Description: Grand canonical Monte Carlo simulations on a cubic lattice are used to examine aggregation and phase separation of model amphiphiles with bulky head groups. The amphiphiles studied consist of a rigid, roughly spherical nanoparticle attached to one or more flexible chains. Overlapping distributions of energy and density are combined via histogram reweighting to obtain the free energy and osmotic pressure as a function of temperature and concentration. Finite ...

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Journal of Applied Physics : Selective transmittance of linearly p...

By: Viktor Leontyev, Nicholas G. Wakefield, Kyrylo Tabunshchyk, Jeremy C. Sit, Michael J. Brett et al

Description: Columnar thin films exhibiting linear polarization selectivity have been theoretically investigated and fabricated using the glancing angle deposition (GLAD) technique. The film structure employed an s-shaped columnar morphology that may be either smoothly bent or composed of discrete segments. Finite-difference time-domain and frequency-domain methods have been used to model these thin film structures numerically. Simulation results have yielded optimal geo...

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Physics of Fluids : Experimental investigation of turbulent diffus...

By: Balaji Gopalan, Edwin Malkiel, and Joseph Katz

Description: High-speed inline digital holographic cinematography is used for studying turbulent diffusion of slightly buoyant 0.5–1.2 mm diameter diesel droplets and 50 μm diameter neutral density particles. Experiments are performed in a 50×50×70 mm3 sample volume in a controlled, nearly isotropic turbulence facility, which is characterized by two dimensional particle image velocimetry. An automated tracking program has been used for measuring velocity time history of ...

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Applied Physics Letters : A flexible organic pentacene nonvolatile...

By: Ming-Feng Chang, Po-Tsung Lee, S. P. McAlister, and Albert Chin

Description: We report a pentacene thin film transistor nonvolatile memory fabricated on a flexible polyimide substrate. This device shows a low program/erase voltage of 12 V, a speed of 1/100 ms, an initial memory window of 2.4 V, and a 0.78 V memory window after 48 h. This has been achieved by using a high-κ dielectric as charge trapping, blocking, and tunneling gate insulator layers.

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Biblioteca Hispanica : Primer Natural History

By: Odo Good
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Journal of Applied Physics : Temperature dependence of voltage-con...

By: T. W. Hickmott

Description: Voltage-controlled negative resistance (VCNR) and unipolar resistive switching that can be used for memory applications can develop in the current-voltage (I-V) curves of metal-insulator-metal diodes. Electroluminescence is intimately connected with the occurrence of VCNR in I-V curves. The temperature dependence of VCNR and electroluminescence of Al–Al2O3–Au diodes with anodic Al2O3 thicknesses between 12 and 54 nm has been studied between 300 and 180 K. Th...

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Physics of Fluids : Favorable pressure gradient turbulent flow ove...

By: Mark F. Tachie and Mohammad K. Shah

Description: This paper reports on experimental study of turbulent flows over straight and inclined transverse ribs of square and triangular cross sections attached to the bottom and top walls of an asymmetric converging channel. The pitch-to-height ratio of the ribs was 10. A particle image velocimetry technique was used to conduct extensive velocity measurements at channel midspan and in planes close to the leading and trailing edges of the inclined ribs. From these me...

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Physics of Fluids : Topology and breakdown of Görtler vortices on ...

By: M. Canals and G. Pawlak

Description:

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Chaos : On the bifurcation of species

By: M.A.Bees,P.H.Coullet, and E.A.Spiegel

Description: We propose and analyze a model of evolution of species based upon a general description of phenotypes in terms of a single quantifiable characteristic. In the model, species spontaneously arise as solitary waves whose members almost never mate with those in other species, according to the rules laid down. The solitary waves in the model bifurcate and we interpret such events as speciation. Our aim in this work is to determine whether a generic mathematical m...

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Applied Physics Letters : Growth behaviors of ultrathin ZnSe nanow...

By: Y. Cai, T. L. Wong, S. K. Chan, I. K. Sou, D. S. Su et al

Description: Ultrathin ZnSe nanowires grown by Au-catalyzed molecular-beam epitaxy show an interesting growth behavior of diameter dependence of growth rates. The smaller the nanowire diameter, the faster is its growth rate. This growth behavior is totally different from that of the nanowires with diameters greater than 60 nm and cannot be interpreted by the classical theories of the vapor-liquid-solid mechanism. For the Au-catalyzed nanowire growth at low temperatures, ...

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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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Journal of Applied Physics : Synthesis of soft/hard magnetic FePt-...

By: Akihiro Makino, Akihiro Kazahari, Wei Zhang, Kunio Yubuta, Takeshi Kubota et al

Description: Since the glassy alloys have structural homogeneity on a nanoscopic scale and wide supercooled liquid region, ΔTx (temperature interval between glass transition and crystallization), these materials are recognized as promising micro/nano-materials for nanomachines or micro electro-mechanical systems (MEMS). As one of the micro/nano components, the hard magnetic one is immensely desired. We systematically investigated the effect of metalloids composition in F...

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Review of Scientific Instruments : Single-sided radio-frequency fi...

By: Laouès Guendouz, Sébastien Leclerc, Alain Retournard, Ahcène Hedjiedj, and Daniel Canet

Description: Magnetic field gradients are nowadays indispensable to most nuclear magnetic resonance experiments and are at the basis of magnetic resonance imaging (MRI). Most of the time, gradients of the static magnetic field are employed. Gradients of the radio-frequency (rf) field may constitute an interesting alternative. Until now, they were produced by a single loop. We demonstrate in this paper how two unsymmetrical series loops can be optimized to produce rf grad...

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