Physical Sciences and Mathematics Commons^™

Optical Control Of Thermocapillary Effects In Complex Nanofluids, Yuval Lamhot, Assaf Barak, Carmel Rotschild, Mordechai Segev, Meirav Saraf, Efrat Lifshitz, Abraham Marmur, Ramy El-Ganainy, Demetrios N. Christodoulides

Ramy El-Ganainy

We study the strong coupling of light and nanoparticle suspensions and their surface tension effect in capillaries. We show experimentally and theoretically that increasing the intensity of a narrow laser beam passing through a capillary far away from the surface results in a significant decrease in the fluid level. The underlying mechanism relies on light-induced redistribution of nanoparticles in the bulk and the surface of the fluid, facilitating continuous optical control over the surface position. The experiments manifest optical control from afar over properties of fluid surfaces.

Nonlinear Optical Dynamics In Nonideal Gases Of Interacting Colloidal Nanoparticles, Ramy El-Ganainy, Demetrios N. Christodoulides, E. M. Wright, W. M. Lee, K. Dholakia

Ramy El-Ganainy

We show that many-body effects in stabilized nanocolloidal suspensions can have a profound effect on their optical nonlinearity. By considering the screened Coulomb repulsions between nanoparticles, we find that the nonlinear optical behavior of these colloids can range from polynomial to exponential depending on their composition and chemistry. The dynamics and stability properties of optical beams propagating in such nonideal gas environments of interacting colloidal particles are investigated. Our analysis provides a theoretical foundation for understanding the recently observed super-Kerr nonlinear optical response of such systems.

Absolute Nitrogen Atom Density Measurements By Two-Photon Laser-Induced Fluorescence Spectroscopy In Atmospheric Pressure Dielectric Barrier Discharges Of Pure Nitrogen, Et-Touhami Es-Sebbar, Christian Sarra-Bournet, Nicolas Naudé, Françoise Massines, Nicolas Gherardi

Dr. Et-touhami Es-sebbar

In this paper, two-photon absorption laser induced fluorescence spectroscopy is used to follow the nitrogen atom density in flowing dielectric barrier discharges fed with pure nitrogen and operating at atmospheric pressure. Two different dielectric barrier discharge regimes are investigated: the Townsend regime, which is homogeneous although operating at atmospheric pressure, and the more common filamentary regime. In both regimes, densities as high as 3x1014 /cm3 are detected. However, the N atoms kinetic formation depends on the discharge regime. The saturation level is reached more rapidly with a filamentary discharge. For a given discharge regime, the N atom density depends strongly …

Contributions To The Development Of The S.E.T.U.P. (Experimental And Theoretical Simulations Useful For Planetology) Project, E. Arzoumanian, C. Romanzin, M-C. Gazeau, Et. Es-Sebbar, A. Jolly, S. Perrier, Y. Benilan

Dr. Et-touhami Es-sebbar

No abstract provided.

Multiwavelength Studies For Titan's Atmospheric Composition Analysis, Y. Benilan, Et. Es-Sebbar, N. Fray, M-C. Gazeau, A. Jolly, M. Schwell, J. Guillemin

Dr. Et-touhami Es-sebbar

Titan's atmosphere mainly made of nitrogen and methane is rich in organic molecules. Hydrocarbons are formed from the photolytic dissociation of CH4 and nitriles are created by dissociation of N2 followed by reactions with hydrocarbons. In order to understand the physicochemical mechanisms responsible for the evolution of Titan's atmosphere, photochemical models are built. The latter need constrains for vertical profiles of organic compounds from the high thermosphere down to the low stratosphere as well as photodissociation rates. Those profiles over the entire atmosphere can be retrieved from Cassini observations, in particular by limb sounding, coupling infrared and ultraviolet spectroscopy. However, …

Electron Self-Injection And Trapping Into An Evolving Plasma Bubble, Serguei Y. Kalmykov, Sunghwan A. Yi, Vladimir N. Khudik, Gennady Shvets

Serge Youri Kalmykov

The blowout (or bubble) regime of laser wakefield acceleration is promising for generating monochromatic high-energy electron beams out of low-density plasmas. It is shown analytically and by particle-in-cell simulations that self-injection of the background plasma electrons into the quasistatic plasma bubble can be caused by slow temporal expansion of the bubble. Sufficient criteria for the electron trapping and bubble’s expansion rate are derived using a semianalytic nonstationary Hamiltonian theory. It is further shown that the combination of bubble’s expansion and contraction results in monoenergetic electron beams.

Vuv Photostability Of Prebiotic Species, M. Schwell, Y. Bénilan, M.-C. Gazeau, N. Fray, A. Jolly, Et. Es-Sebbar, N. Champion, S. Leach, H. W Jochims, H. Baumgärtel, E. Rühl

Dr. Et-touhami Es-sebbar

No abstract provided.

S.E.T.U.P. Experimental And Theoretical Simulations Useful For Planetology- Related Studies In The Frame Of A Program Of Titan’S Atmosphere Laboratory Simulations, M.-C. Gazeau, Et. Es-Sebbar, E. Arzoumanian, C. Romanzin, A. Jolly, S. Perrier, Y. Bénilan

Dr. Et-touhami Es-sebbar

No abstract provided.

Flexoelectricity Of A Calamitic Liquid Crystal Elastomer Swollen With A Bent-Core Liquid Crystal, M. Chambers, R. Verduzco, J. T. Gleeson, S. Sprunt, Antal Jakli

Antal Jakli

We have measured the electric current induced by mechanical distortion of a calamitic liquid crystal elastomer (LCE) swollen with a low molecular weight bent-core nematic (BCN) liquid crystal, and have determined, for the first time, the bend flexoelectric coefficient e(3) of such a BCN-LCE composite. In one method, we utilise air-pressure to induce a mechanical bend deformation and flexoelectric polarization in a BCN-LCE film, and then measure the polarization current as a function of time. An alternative technique uses a rotary-motor driven scotch yoke to periodically flex the BCN-LCE; in this case, the magnitude and phase of the induced current …

Light-Driven Molecular Switches With Tetrahedral And Axial Chirality, Lisa Green, Yannian Li, Timothy White, Augustine Urbas, Timothy Bunning, Quan Li

Quan Li

Two light-driven molecular switches with tetrahedral and axial chirality were synthesized, which can induce a helical superstructure in an achiral liquid crystal host and dynamically phototune it to achieve reversible reflection color.

Rheological Properties Of Bent-Core Liquid Crystals, C. Bailey, K. Fodor-Csorba, J. T. Gleeson, Samuel N. Sprunt, Antal Jákli

Antal Jakli

We show that bent-core liquid crystalline materials exhibit non-Newtonian flow in their optically isotropic liquid phase. We conjecture that this behavior is due to the existence of nanostructured, fluctuating clusters composed of a few smectic-like layers. Shear alignment of these clusters explains the shear thinning observed in bent-core liquid crystals having either a nematic phase or non-modulated smectic phase. By contrast, smectogens having a modulated smectic phase do not shear thin at low shear rates, but even show a slight shear thickening which may be due to entanglements of wormlike and/or helical clusters.

Charge Transfer Assisted By Collective H-Bonding Network Dynamics, Omar F. Mohammed, Christina M. Othon, Oh-Hoon Kwon, Ahmed H. Zewail

Christina M Othon

Although there have been numerous studies of solvation, the role of solvent specific and collective interactions, especially for charge-transfer processes, remains difficult to unravel. Here, we report, using femtosecond fluorescence up-conversion and steady-state spectroscopic measurements, studies of well-designed single-sited formylperylene (FPe) in binary solvents. One of the solvents (methanol, MOH) can selectively hydrogen (H) bond to the carbonyl (C=O) site, while the other (acetonitrile, ACN) cannot, but both have similar polarity ( for MOH and for ACN). The results reveal that ultrafast charge transfer from the perylene unit to the carbonyl group of FPe is facilitated by site-specific H-bonding interactions …

Comet C/2004 Q2 (Machholz): Parent Volatiles, A Search For Deuterated Methane, And Constraint On The Ch4 Spin Temperature, Boncho P. Bonev, Michael J. Mumma, Erika L. Gibb, Michael A. Disanti, Geronimo L. Villanueva, Karen Magee-Sauer, Richard S. Ellis

Erika Gibb

Acoustically Driven Oscillations Of Freely Suspended Liquid Crystal Filaments, J. Petzold, A. Nemes, A. Eremin, C. Bailey, N. Diorio, Antal Jakli, R. Stannarius

Antal Jakli

Some liquid crystalline phases of bent-core mesogens are known to form stable freely-suspended filaments with length to diameter ratios of 1000 and larger. These structures can behave like thin liquid chords. We study filament oscillations excited with harmonic sound waves. From amplitudes of the filament motion and phase shifts respective to the harmonic excitation signal we develop a model for the filament dynamics. Like in solid chords, the resonance frequency f(0) is inversely proportional to their length. The dependence of f(0) upon the filament radius allows one to draw conclusions on the nature of the filament tension. For thin filaments, …

Characterization Of An N2 Flowing Microwave Post-Discharge By Oes Spectroscopy And Determination Of Absolute Ground-State Nitrogen Atom Densities By Talif, Et. Es-Sebbar, Y. Benilan, A. Jolly, M-C. Gazeau

Dr. Et-touhami Es-sebbar

A flowing microwave post-discharge source sustained at 2.45 GHz in pure nitrogen has been investigated by optical emission spectroscopy (OES) and two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. Variations of the optical emission along the post-discharge (near, pink and late afterglow) have been studied and the gas temperature has been determined. TALIF spectroscopy has been used in the late afterglow to determine the absolute ground-state nitrogen atomic densities using krypton as a reference gas. Measurements show that the microwave flowing post-discharge is an efficient source of N (4S) atoms in late afterglow. In our experimental conditions, the maximum N (4S) density …

Solvation In Protein (Un)Folding: Effect Of Local And Bulk Dynamics In The Melittin Tetramer-Monomer Transition, Christina M. Othon, Oh-Hoon Kwon, Milo M. Lin, Ahmed H. Zewail

Christina M Othon

Protein structural integrity and flexibility are intimately tied to solvation. Here we examine the effect that changes in bulk and local solvent properties have on protein structure and stability. We observe the change in solvation of an unfolding of the protein model, melittin, in the presence of a denaturant, trifluoroethanol. The peptide system displays a well defined transition in that the tetramer unfolds without disrupting the secondary or tertiary structure. In the absence of local structural perturbation, we are able to reveal exclusively the role of solvation dynamics in protein structure stabilization and the (un)folding pathway. A sudden retardation in …

Analytical Solution For Stokes Flow Inside An Evaporating Sessile Drop: Spherical And Cylindrical Cap Shapes, Hassan Masoud, James D. Felske

Hassan Masoud

Organo-Soluble Photoresponsive Azo Thiol Monolayer-Protected Gold Nanorods, Jouliana M. El Khoury, Xiaoli Zhou, Liangti Qu, Liming Dai, Augustine Urbas, Quan Li

Quan Li

Organo-soluble photoresponsive azo thiol monolayer-protected gold nanorods were synthesized; the resulting gold nanorods encapsulated by thiols on their entire surface with strong covalent Au-S linkages were very stable in both organic solvents and in the solid state without aggregation or decomposition.

Ir-Dielectric Functions Of Znbete Alloys Determined By Spectroscopic Ellipsometry, Frank Peiris, Et Al.

Frank Peiris

All-Optical Control Of Nonlinear Focusing Of Laser Beams In Plasma Beat Wave Accelerator, Serguei Y. Kalmykov, Sunghwan A. Yi, Gennady Shvets

Serge Youri Kalmykov

Nonlinear focusing of a bi-color laser in plasma can be controlled by varying the difference frequency \Omega. The driven electron density perturbation forms a co-moving periodic focusing (de-focusing) channel if \Omega is below (above) the electron Langmuir frequency \omega_p. Hence, the beam focusing is enhanced for \Omega < \omega_p and is suppressed otherwise. In particular, a catastrophic relativistic self-focusing of a high-power laser beam can be prevented all-optically by a second, much weaker, co-propagating beam shifted in frequency by \Omega > \omega_p. A bi-envelope equation describing the early stage of the mutual de-focusing is derived and analyzed. Later stages, characterized by a well-developed electromagnetic cascade, are investigated numerically. Stable propagation of the over-critical laser pulse over several Rayleigh lengths is predicted. The non-resonant plasma beat wave (\Omega \not= \omega_p) can accelerate pre-injected electrons above …

First Measurement Of The Neutron Beta Asymmetry With Ultracold Neutrons, Robert W. Pattie, J. Anaya, Henning O. Back, J. G. Boissevain, Thomas J. Bowles, Leah J. Broussard, Richard Carr, D. J. Clark, Scott Currie, S. Du, Bradley W. Filippone, Peter Geltenbort, A. García, Ayman I. Hawari, Kevin P. Hickerson, R. Hill, M. Hino, S. A. Hoedl, Gary E. Hogan, Anthony T. Holley, Takeyasu M. Ito, T. Kawai, K. Kirch, S. Kitagaki, Steve K. Lamoreaux, Chenyu Liu, Jingyang Liu, Mark Makela, Russell R. Mammei, J. W. Martin, Daniel Melconian, N. Meier, Michael P. Mendenhall, Charles L. Morris, R. Mortensen, A. Pichlmaier, Margaret L. Pitt, Blakely Plaster, John C. Ramsey, Roger Rios, Konstantin Sabourov, A. L. Sallaska, Alexander Saunders, R. Schmid, Susan J. Seestrom, C. Servicky, Sky K. L. Sjue, D. Smith, Walter E. Sondheim, E. Tatar, W. Teasdale, Christopher R. Terai, B. Tipton, M. Utsuro, R. Bruce Vogelaar, Bernard Wehring, Y. P. Xu, Andrew R. Young, J. Yuan

Robert W. Pattie Jr.

Elliptical Orbit Node Passage Time, Eric Addison

Eric Addison

The node passage time is calculated in order to gain an understanding of the kind of velocities and time scales will be involved in BEMRI simulations during close encounters with the SMBH. The result is generalized to produce a function of time with respect to theta, t(θ).

Living Anionic Polymerization Using A Microfluidic Reactor, Kazunori Iida, Thomas Q. Chastek, Kathryn L. Beers, Kevin Cavicchi, Jaehun Chun, Fasolka J. Michael

Kevin Cavicchi

Living anionic polymerizations were conducted within aluminum-polyimide microfluidic devices. Polymerizations of styrene in cyclohexane were carried out at various conditions, including elevated temperature (60 degrees C) and high monomer concentration (42%, by volume). The reactions were safely maintained at a controlled temperature at all points in the reactor. Conducting these reactions in a batch reactor results in uncontrolled heat generation with potentially dangerous rises in pressure. Moreover, the microfluidic nature of these devices allows for flexible 2D designing of the flow channel. Four flow designs were examined (straight, periodically pinched, obtuse zigzag, and acute zigzag channels). The ability to use …

Alamethicin In Lipid Bilayers: Combined Use Of X-Ray Scattering And Md Simulations, Jianjun Pan, D. Peter Tieleman, John F. Nagle, Norbert Kučerka, Prof. Stephanie Tristram-Nagle Ph.D.

Prof. Stephanie Tristram-Nagle Ph.D.

We study fully hydrated bilayers of two di-monounsaturated phospholipids diC18:1PC (DOPC) and diC22:1PC with varying amounts of alamethicin (Alm). We combine the use of X-ray diffuse scattering and molecular dynamics simulations to determine the orientation of alamethicin in model lipids. Comparison of the experimental and simulated form factors shows that Alm helices are inserted transmembrane at high humidity and high concentrations, in agreement with earlier results. The X-ray scattering data and the MD simulations agree that membrane thickness changes very little up to 1/10 Alm/ DOPC. In contrast, the X-ray data indicate that the thicker diC22:1PC membrane thins with added …

Patent Citation Networks Revisited: Signs Of A Twenty-First Century Change, Katherine J. Strandburg, Gabor Csardi, Laszlo Zalanyi, Jan Tobochnik, Peter Erdi

Katherine J. Strandburg

This Article reports an empirical study of the network composed of patent “nodes” and citation “links” between them. It builds on an earlier study, in which we argued that trends in the growth of the patent citation network provide evidence that the explosive growth in patenting in the late twentieth century was due at least in part to the issuance of increasingly trivial patents. We defined a measure of patent stratification based on comparative probability of citation; an increase in this measure suggests that the USPTO is issuing patents of comparatively less technological significance. Provocatively, we found that stratification increased …

Appearance Of A Fractional Stokes-Einstein Relation In Water And A Structural Interpretation Of Its Onset, L. Xu, F. Mallamace, Z. Yan, Francis W. Starr, S. V. Buldyrev, H. E. Stanley

Francis Starr

The Stokes–Einstein relation has long been regarded as one of the hallmarks of transport in liquids. It predicts that the self-diffusion constant D is proportional to (τ/T)−1, where τ is the structural relaxation time and T is the temperature. Here, we present experimental data on water confirming that, below a crossover temperature T× ≈ 290 K, the Stokes– Einstein relation is replaced by a ‘fractional’ Stokes–Einstein relation D ∼ (τ/T)−ζ with ζ ≈ 3/5 (refs 1–6). We interpret the microscopic origin of this crossover by analysing the OH- stretch region of the Fourier transform infrared spectrum over a temperature range …

Review Of Biocd Physics And Technology, David D. Nolte

David D Nolte

Spinning biodisks have advantages that make them attractive for specialized biochip applications. The two main classes of spinning biodisks are microfluidic disks and bio-optical compact disks BioCD. Microfluidic biodisks take advantage of noninertial pumping for lab-on-a-chip devices using noninertial valves and switches under centrifugal and Coriolis forces to distribute fluids about the disks. BioCDs use spinning-disk interferometry, under the condition of common-path phase quadrature, to perform interferometric label-free detection of molecular recognition and binding. The optical detection of bound molecules on a disk is facilitated by rapid spinning that enables high-speed repetitive sampling to eliminate 1/ f noise through common-mode …

Problems Of Local Fractional Definite Integral Of The One-Variable Non-Differentiable Function, Yang Xiao-Jun

Xiao-Jun Yang

It is proposed that local fractional calculas introduced by Kolwankar and Gangal is extended by the concept of Jumarie’s fractional calculus and local fractional definite integral is redefined. The properties and the theorems of local fractional calculus are discussed in this paper.

Multilayered Structures In The Ionosphere F2 Region And Impulse-Like Increase Of The Nightglow Red 630 Nm Line Intensity As A Result Of Influence Of Shear Excited Atmospheric Vortical Perturbations, G. G. Didebulidze, Levan Lomidze, N. B. Gudadze, M. Todua

Levan Lomidze

It is shown that the formation of multilayered structures in the midlatitude ionosphere F 2 layer can be caused by atmospheric vortical perturbation (shear wave) evolving in the meridional wind with linear zonal shear and can be accompanied by an impulse-like increase (with duration about 1–3 h) in the red 630 nm line total nightglow intensity. The shear wave can produce an enhancement of the northward wind (or decrease in the southward one), which can cause a downward motion of the F 2 layer peak height resulting in the impulse-like increase in the red line intensity. An important increase in …